US20060290317A1 - Maximum power point motor control - Google Patents
Maximum power point motor control Download PDFInfo
- Publication number
- US20060290317A1 US20060290317A1 US11/158,876 US15887605A US2006290317A1 US 20060290317 A1 US20060290317 A1 US 20060290317A1 US 15887605 A US15887605 A US 15887605A US 2006290317 A1 US2006290317 A1 US 2006290317A1
- Authority
- US
- United States
- Prior art keywords
- inverter
- source
- motor
- frequency
- power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 claims abstract description 14
- 230000008859 change Effects 0.000 claims description 25
- 238000005070 sampling Methods 0.000 claims description 16
- 230000004044 response Effects 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 230000003247 decreasing effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000008570 general process Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/0077—Characterised by the use of a particular software algorithm
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/02016—Circuit arrangements of general character for the devices
- H01L31/02019—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02021—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier for solar cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S323/00—Electricity: power supply or regulation systems
- Y10S323/906—Solar cell systems
Definitions
- the present invention relates generally to the operation of AC motors or similar loads with AC motor drives that convert power from a DC source to AC, and more particularly to operation of the motor at maximum power as the power from the-DC source varies.
- a particular application is to solar powered systems and to water pumps.
- An AC load can be powered from a DC source by using a converter to change DC to AC.
- a photovoltaic solar cell array is a DC source.
- the current-voltage (I-V) curve shifts under varying conditions, e.g. amount of sun.
- the available power will vary.
- One application of solar power is to operate water pumps, which typically include three phase AC motors.
- the load curve of the AC pump motor can also shift with varying conditions, e.g. water depth. Thus it can be difficult to efficiently operate an AC pump from a solar array.
- a solar powered water pumping system typically has three primary components: the solar array, made of photovoltaic (PV) modules; a converter (inverter or motor drive) which converts the DC from the PV array to AC; and an AC motor (pump).
- the motor typically runs at a particular frequency (speed), e.g. 60 Hz.
- the converter will usually be set to provide AC power at that particular frequency.
- the motor will run at a speed equal to the AC frequency.
- the motor demands power.
- the motor pumps the most water when it is at the maximum power point.
- the solar array output changes, e.g. decreases from a maximum to a lower voltage
- the I-V power curve changes, but there is always a maximum power point.
- the motor continues to run at the same speed, e.g. 60 Hz, then as the voltage drops, the current must increase to meet the power requirements, until the increased current can damage the motor.
- Power tracking generally requires detecting two parameters, current (I) and voltage (V), and measuring changes in the product (IV).
- the motor operates at a reduced frequency, then it requires less power. While this is not as good as operating at full power, the motor can be kept operating at the maximum operating frequency for the existing conditions, without damaging the motor. Therefore, it is desirable to provide a method and apparatus to operate an AC motor from a motor drive by changing the AC frequency and thus the motor speed to correspond to the available power.
- U.S. Pat. No. 6,275,403 is directed to a bias control circuit connected to a DC to AC converter to control motor frequency of a connected motor by applying a bias voltage to the converter to control the frequency of the AC output of the converter.
- the bias control circuit is responsive to the DC voltage from a DC source, e.g. solar array, connected to the converter.
- the system is designed to operate an AC motor or other load from a DC source under varying source and/or load conditions.
- the bias control circuit has a multistage configuration and provides bias voltages at a plurality of discrete DC source voltages.
- the system while providing significant improvement in motor operation, requires an additional hardware circuit, and operates at a number of discrete levels limited by the number of stages in the circuit.
- the invention is method and apparatus implemented in software to control motor speed as a function of available power in a DC source - inverter - AC motor system, i.e. to perform maximum power tracking of motor speed.
- An inverter or motor drive is used to convert DC power from a DC source, such as a solar panel, to AC power, which powers the motor.
- the inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power.
- the software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage, which is input into the inverter or drive.
- the software-controlled inverter of the invention samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.
- An aspect of the invention is an apparatus for converting DC power from a DC source to AC power to drive an AC motor, formed of a software-controlled inverter which produces an AC output from a DC input, wherein the software-controlled inverter carries out an algorithm for varying the AC output frequency in response to changes in the DC voltage from the DC source so that the speed of an AC motor driven by the inverter tracks the maximum power available from the DC source.
- Another aspect of the invention is a system including a DC source; a software-controlled inverter connected to the DC source to produce an AC output from a DC input; and an AC motor connected to the AC output from the inverter; wherein the software-controlled inverter carries out an algorithm for varying the AC output frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source.
- a further aspect of the invention is a method for powering an AC motor from a DC source by obtaining DC power from a DC source; converting the DC power to AC power; powering the AC motor with the AC power; and varying the AC frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source.
- FIG. 1A is a block diagram of a DC source—software controlled inverter—AC motor system of the invention, with a separate controller.
- FIG. 1B is a block diagram of an alternate embodiment of the software controlled inverter, with an internal controller.
- FIG. 2 is a series of current (I) vs. voltage (V) curves for a PV solar array with the maximum power point (MPP) and associated power (P) vs. voltage (V) curves also shown.
- FIG. 3A is a graph of measured I-V for changes in motor frequency.
- FIG. 3B is a graph of power consumption vs. frequency.
- FIG. 4 is a flow chart of a maximum power point algorithm used by the invention.
- FIG. 5 is a flow chart of some specific steps in an algorithm for maximum power tracking.
- FIG. 6 is a maximum power tracking timing diagram for the specific steps of the algorithm of FIG. 5 .
- a DC source—software controlled inverter—AC motor system 10 comprises a DC source 12 , an inverter 14 connected to the DC source 12 , a programmed controller 16 connected to the inverter 14 , and an AC motor 18 connected to the inverter 14 .
- DC source 12 is preferably a solar array made up of conventional silicon solar cells or panels, but may be another type of DC source.
- the DC source will generally be a source whose output voltage and power vary.
- the AC motor is typically a three phase motor, and may drive a water pump 20 (or other device), which may be combined with motor 18 into a single integral unit 19 .
- the invention may also be applied to other loads that have load characteristics similar to motor 18 .
- Inverter 14 is a conventional DC to AC converter, also commonly known as a motor drive or variable speed drive (VFD). Controller 16 is programmed to carry out an algorithm which produces maximum power point tracking by varying the AC output frequency from the inverter 14 as a function of the DC source voltage.
- inverter 14 and controller 16 are replaced by inverter 15 with an internal controller 17 , as shown in FIG. 1B , i.e. the inverter is itself programmable and does not need an external controller.
- Controller 17 is programmed to carry out an algorithm which produces maximum power point tracking by varying the AC output frequency from the inverter 15 as a function of the DC source voltage.
- the DC to AC converter is software-controlled and carries out an algorithm to vary the AC frequency so that the motor is operated at the maximum power that is at that moment available from the DC source.
- the motor speed changes as the available power from the DC source changes.
- the invention includes the software-controlled inverter and the DC source—software controlled inverter—AC motor system.
- FIG. 2 shows several current (I) vs. voltage (V) curves for a PV solar array, ranging between high sun and low sun conditions.
- the maximum power points (MPPs) and some associated power (P) vs. voltage (V) curves are also shown.
- the motor being powered from the PV array can do the most work when it is at the MPP.
- the invention provides a way for the motor to track the MPP. This is accomplished by. measuring the DC voltage, and changing the AC frequency (and thus motor speed) in response thereto.
- FIG. 3A shows a solar I-V curve for changes in motor frequency. Tests were run at different frequencies and the power requirements, i.e. maximum IV, were logged at each frequency. The curve ranges from zero frequency, where the solar voltage is the open circuit voltage Voc and the solar current is zero, to the maximum frequency. At the other limit the solar voltage is zero and the solar current is the short circuit current Isc (but a motor would stall before reaching that point). The graph shows that the motor can be controlled for maximum power available from a solar source (or other variable DC source).
- the motor is allowed to operate at a frequency compatible with source power, but this is done without actually sampling the source power. Instead, only the source voltage is sampled, and on the basis of changes in the source voltage the motor speed is decreased or increased to track lower or higher power availability.
- FIG. 3B shows a power consumption curve as a function of frequency.
- Motors in the U.S. are designed to operate at 60 Hz AC frequency at rated power. If the motor power available is less than the power required at 60 Hz, the motor will try to maintain constant power by increased current consumption to compensate for the reduction in source voltage. This will add to excessive power losses and eventual motor damage. To correct this problem, motor speed must be reduced. As shown in FIG. 3B , at full power the motor can operate at full speed (60 Hz) but at 80% power the motor speed must be reduced to about 55 Hz and at 60% power the motor speed must be reduced to about 50 Hz.
- the invention provides a simple method and apparatus for adjusting motor speed to track available source power.
- FIG. 4 presents a flow chart of an algorithm which is implemented by the software controlled inverter of the invention to carry out maximum power point tracking.
- a sampling interval ( ⁇ t) is set.
- the sampling interval should be relatively short so that the motor speed closely follows the available power but cannot be so short that the motor operation becomes unstable because of very rapid fluctuations in power or that the motor cannot respond because of motor inertia.
- a suitable At is in the range of about 1 to 5 sec. The sampling interval can be reset as desired.
- step 30 the array voltage (AV) is sampled. Sampling is done at the sampling interval set in step 30 .
- step 36 a decision as to whether a change in frequency is required is made, based on the comparison made in step 34 .
- a comparison is made as to whether the measured ⁇ AV is greater than or equal to a preset threshold value ⁇ AV(threshold).
- ⁇ AV(threshold) represents the minimum change in voltage (and power) for which the motor speed should be changed. It should be relatively low so that the motor speed closely follows the available power but cannot be so small that the system tries to respond to insignificant changes in voltage (power).
- a suitable value is in the range of about 10 to 25 volts.
- step 32 If the measured ⁇ AV is less than ⁇ AV(threshold), then no change in AC frequency or motor speed is required, and the algorithm returns to step 32 , takes the next voltage sample, and continues on through step 34 to step 36 again. If the measured ⁇ AV is greater than or equal to ⁇ AV(threshold), then a change in AC frequency and motor speed is required.
- a control signal is produced in step 38 .
- the control signal may be generated internal to the inverter, as in FIG. 1B , or may be generated in a separate controller, as in FIG. 1A .
- the inverter changes the AC frequency of its output, in step 40 .
- the change in AC frequency changes the motor speed, step 42 , so that the motor speed tracks the maximum power available from the source.
- the algorithm returns to step 32 and goes through another cycle.
- the general process of the algorithm shown in FIG. 4 can be carried out in many different specific software implementations.
- the invention includes a method for powering an AC motor from a DC source, e.g. solar panel, by obtaining DC power from the DC source; converting the DC power to AC power; powering the AC motor with the AC power; and varying the AC frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source.
- a DC source e.g. solar panel
- the method may be carried out with an algorithm made up of a series of instructions for sequentially sampling the DC source voltage at a preset sampling interval, comparing the present sampled value of the DC voltage to the prior sampled value, determining whether a change of AC frequency is required based on the comparison of the present to the prior sampled DC voltages, producing a control signal if a change in AC frequency is required, changing the AC frequency in response to the control signal, and continuously repeating the series of instructions.
- FIG. 5 A specific sequence of steps illustrating a portion of a particular algorithm for maximum power point tracking is shown in FIG. 5 , and an illustrative associated wave form and timing diagram is shown in FIG. 6 .
- This sequence starts with an initial array voltage V 0 (the maximum voltage), step 50 , at t 0 .
- a first voltage sample V 1 is taken at time t 1 , step 51 .
- step 51 Also return to step 51 and start a new cycle. If No, then V 2 >V 1 , the voltage has increased since the last voltage sample (but not to V 0 ) so the speed should be increased, using signal B. Again return to step 51 and start a new cycle.
- FIG. 6 shows illustrative Voltage (V), Speed (S) and Power (P) wave forms for the process illustrated in FIG. 5 .
- V is at its maximum value V 0 so S and P are at their maximums S 0 and P 0 .
- the voltage sampling and speed adjustment is done at a sequence of times t 1 , t 2 , t 3 . . . t(n ⁇ 1), t(n) defined by a sampling interval.
- V has decreased to V 1 and P to P 1 so the speed must be reduced to S 1 .
- the V and P have decreased further to V 2 and P 2 so the speed must be further reduced to S 2 .
- V, S, and P then remain constant up to sample time t(n ⁇ 1). But at sample time t(n), V and P have increased back to their maximum values V 0 , P 0 so S must be increased back to S 0 .
- the method of FIG. 5 will allow S to track P using V.
Abstract
Description
- 1. Field of the Invention
- The present invention relates generally to the operation of AC motors or similar loads with AC motor drives that convert power from a DC source to AC, and more particularly to operation of the motor at maximum power as the power from the-DC source varies. A particular application is to solar powered systems and to water pumps.
- 2. Description of Related Art
- An AC load can be powered from a DC source by using a converter to change DC to AC. However, because of changes in both the source and the load, it can be difficult to meet the power requirements of the load. For example, a photovoltaic solar cell array is a DC source. However, the current-voltage (I-V) curve shifts under varying conditions, e.g. amount of sun. Thus the available power will vary. One application of solar power is to operate water pumps, which typically include three phase AC motors. However, the load curve of the AC pump motor can also shift with varying conditions, e.g. water depth. Thus it can be difficult to efficiently operate an AC pump from a solar array.
- A solar powered water pumping system typically has three primary components: the solar array, made of photovoltaic (PV) modules; a converter (inverter or motor drive) which converts the DC from the PV array to AC; and an AC motor (pump). The motor typically runs at a particular frequency (speed), e.g. 60 Hz. The converter will usually be set to provide AC power at that particular frequency. The motor will run at a speed equal to the AC frequency.
- In operation, the motor demands power. The motor pumps the most water when it is at the maximum power point. As the solar array output changes, e.g. decreases from a maximum to a lower voltage, the I-V power curve changes, but there is always a maximum power point. However, if the motor continues to run at the same speed, e.g. 60 Hz, then as the voltage drops, the current must increase to meet the power requirements, until the increased current can damage the motor.
- Thus, controlling motors at fixed frequency is very difficult. If the power is to remain constant at a given frequency, then a change in DC voltage must be accompanied by a change in DC current. If the voltage decreases, the current must increase, which results in a further voltage decrease and current increase until a point is reached where a shutdown must occur to prevent motor damage or increased heat or other related damage.
- In general, it is desirable to operate at the maximum power point (MPP) on a power curve. However, it is difficult to track power. Power tracking generally requires detecting two parameters, current (I) and voltage (V), and measuring changes in the product (IV).
- If the motor operates at a reduced frequency, then it requires less power. While this is not as good as operating at full power, the motor can be kept operating at the maximum operating frequency for the existing conditions, without damaging the motor. Therefore, it is desirable to provide a method and apparatus to operate an AC motor from a motor drive by changing the AC frequency and thus the motor speed to correspond to the available power.
- U.S. Pat. No. 6,275,403 is directed to a bias control circuit connected to a DC to AC converter to control motor frequency of a connected motor by applying a bias voltage to the converter to control the frequency of the AC output of the converter. The bias control circuit is responsive to the DC voltage from a DC source, e.g. solar array, connected to the converter. The system is designed to operate an AC motor or other load from a DC source under varying source and/or load conditions. In a preferred embodiment, the bias control circuit has a multistage configuration and provides bias voltages at a plurality of discrete DC source voltages. Thus the system, while providing significant improvement in motor operation, requires an additional hardware circuit, and operates at a number of discrete levels limited by the number of stages in the circuit.
- Accordingly it is desirable to provide a simple system for controlling the motor speed to better match the maximum power point without having to measure power. It would also be desirable to provide a system which is implemented in software and eliminates the need for additional hardware circuits.
- The invention is method and apparatus implemented in software to control motor speed as a function of available power in a DC source - inverter - AC motor system, i.e. to perform maximum power tracking of motor speed. An inverter or motor drive is used to convert DC power from a DC source, such as a solar panel, to AC power, which powers the motor. The inverter or motor drive is controlled by software, implemented either by programmable features built directly into the inverter or drive or by a separate programmable device connected to the inverter or drive, to track motor power as a function of source power. The software-controlled inverter or drive sets motor speed as a function of source power by sensing only a single parameter, the DC source voltage, which is input into the inverter or drive. The software-controlled inverter of the invention samples the source voltage at preset intervals, and changes the frequency of the AC output of the inverter or drive to match or track the available power so that the motor operates at or near its optimum for any source voltage.
- An aspect of the invention is an apparatus for converting DC power from a DC source to AC power to drive an AC motor, formed of a software-controlled inverter which produces an AC output from a DC input, wherein the software-controlled inverter carries out an algorithm for varying the AC output frequency in response to changes in the DC voltage from the DC source so that the speed of an AC motor driven by the inverter tracks the maximum power available from the DC source.
- Another aspect of the invention is a system including a DC source; a software-controlled inverter connected to the DC source to produce an AC output from a DC input; and an AC motor connected to the AC output from the inverter; wherein the software-controlled inverter carries out an algorithm for varying the AC output frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source.
- A further aspect of the invention is a method for powering an AC motor from a DC source by obtaining DC power from a DC source; converting the DC power to AC power; powering the AC motor with the AC power; and varying the AC frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source.
- In the accompanying drawings:
-
FIG. 1A is a block diagram of a DC source—software controlled inverter—AC motor system of the invention, with a separate controller. -
FIG. 1B is a block diagram of an alternate embodiment of the software controlled inverter, with an internal controller. -
FIG. 2 is a series of current (I) vs. voltage (V) curves for a PV solar array with the maximum power point (MPP) and associated power (P) vs. voltage (V) curves also shown. -
FIG. 3A is a graph of measured I-V for changes in motor frequency. -
FIG. 3B is a graph of power consumption vs. frequency. -
FIG. 4 is a flow chart of a maximum power point algorithm used by the invention. -
FIG. 5 is a flow chart of some specific steps in an algorithm for maximum power tracking. -
FIG. 6 is a maximum power tracking timing diagram for the specific steps of the algorithm ofFIG. 5 . - As shown in
FIG. 1A , a DC source—software controlled inverter—AC motor system 10 according to the invention comprises aDC source 12, aninverter 14 connected to theDC source 12, a programmedcontroller 16 connected to theinverter 14, and anAC motor 18 connected to theinverter 14.DC source 12 is preferably a solar array made up of conventional silicon solar cells or panels, but may be another type of DC source. The DC source will generally be a source whose output voltage and power vary. The AC motor is typically a three phase motor, and may drive a water pump 20 (or other device), which may be combined withmotor 18 into a singleintegral unit 19. The invention may also be applied to other loads that have load characteristics similar tomotor 18. -
Inverter 14 is a conventional DC to AC converter, also commonly known as a motor drive or variable speed drive (VFD).Controller 16 is programmed to carry out an algorithm which produces maximum power point tracking by varying the AC output frequency from theinverter 14 as a function of the DC source voltage. In an alternate embodiment of the invention,inverter 14 andcontroller 16 are replaced byinverter 15 with aninternal controller 17, as shown inFIG. 1B , i.e. the inverter is itself programmable and does not need an external controller.Controller 17 is programmed to carry out an algorithm which produces maximum power point tracking by varying the AC output frequency from theinverter 15 as a function of the DC source voltage. In either embodiment, the DC to AC converter is software-controlled and carries out an algorithm to vary the AC frequency so that the motor is operated at the maximum power that is at that moment available from the DC source. The motor speed changes as the available power from the DC source changes. The invention includes the software-controlled inverter and the DC source—software controlled inverter—AC motor system. -
FIG. 2 shows several current (I) vs. voltage (V) curves for a PV solar array, ranging between high sun and low sun conditions. The maximum power points (MPPs) and some associated power (P) vs. voltage (V) curves are also shown. The MPP is the point on a particular I-V curve where P (=I×V) is a maximum. The motor being powered from the PV array can do the most work when it is at the MPP. - As the solar array output changes, and the associated I-V curve changes, the MPP changes. To optimize motor performance, it is necessary to adjust to the change in MPP. The invention provides a way for the motor to track the MPP. This is accomplished by. measuring the DC voltage, and changing the AC frequency (and thus motor speed) in response thereto.
-
FIG. 3A shows a solar I-V curve for changes in motor frequency. Tests were run at different frequencies and the power requirements, i.e. maximum IV, were logged at each frequency. The curve ranges from zero frequency, where the solar voltage is the open circuit voltage Voc and the solar current is zero, to the maximum frequency. At the other limit the solar voltage is zero and the solar current is the short circuit current Isc (but a motor would stall before reaching that point). The graph shows that the motor can be controlled for maximum power available from a solar source (or other variable DC source). - In accordance with the invention, the motor is allowed to operate at a frequency compatible with source power, but this is done without actually sampling the source power. Instead, only the source voltage is sampled, and on the basis of changes in the source voltage the motor speed is decreased or increased to track lower or higher power availability.
-
FIG. 3B shows a power consumption curve as a function of frequency. Motors in the U.S. are designed to operate at 60 Hz AC frequency at rated power. If the motor power available is less than the power required at 60 Hz, the motor will try to maintain constant power by increased current consumption to compensate for the reduction in source voltage. This will add to excessive power losses and eventual motor damage. To correct this problem, motor speed must be reduced. As shown inFIG. 3B , at full power the motor can operate at full speed (60 Hz) but at 80% power the motor speed must be reduced to about 55 Hz and at 60% power the motor speed must be reduced to about 50 Hz. The invention provides a simple method and apparatus for adjusting motor speed to track available source power. -
FIG. 4 presents a flow chart of an algorithm which is implemented by the software controlled inverter of the invention to carry out maximum power point tracking. As apreliminary step 30, a sampling interval (Δt) is set. The sampling interval should be relatively short so that the motor speed closely follows the available power but cannot be so short that the motor operation becomes unstable because of very rapid fluctuations in power or that the motor cannot respond because of motor inertia. A suitable At is in the range of about 1 to 5 sec. The sampling interval can be reset as desired. - In
step 30, the array voltage (AV) is sampled. Sampling is done at the sampling interval set instep 30. Instep 34, the present value of the array voltage is compared to the previously sampled value, i.e. the difference ΔAV=AV(n)−AV(n−1) is computed. (On the initial AV sample when the system is first turned on, there is no previous value of AV to compare so the difference is zero.) - In
step 36, a decision as to whether a change in frequency is required is made, based on the comparison made instep 34. A comparison is made as to whether the measured ΔAV is greater than or equal to a preset threshold value ΔAV(threshold). The value ΔAV(threshold) represents the minimum change in voltage (and power) for which the motor speed should be changed. It should be relatively low so that the motor speed closely follows the available power but cannot be so small that the system tries to respond to insignificant changes in voltage (power). A suitable value is in the range of about 10 to 25 volts. - If the measured ΔAV is less than ΔAV(threshold), then no change in AC frequency or motor speed is required, and the algorithm returns to step 32, takes the next voltage sample, and continues on through
step 34 to step 36 again. If the measured ΔAV is greater than or equal to ΔAV(threshold), then a change in AC frequency and motor speed is required. - In response to a Yes decision in
step 36, a control signal is produced instep 38. The control signal may be generated internal to the inverter, as inFIG. 1B , or may be generated in a separate controller, as inFIG. 1A . In response to the control signal, the inverter changes the AC frequency of its output, instep 40. The change in AC frequency changes the motor speed,step 42, so that the motor speed tracks the maximum power available from the source. After the AC frequency is changed instep 40, the algorithm returns to step 32 and goes through another cycle. The general process of the algorithm shown inFIG. 4 can be carried out in many different specific software implementations. - The invention includes a method for powering an AC motor from a DC source, e.g. solar panel, by obtaining DC power from the DC source; converting the DC power to AC power; powering the AC motor with the AC power; and varying the AC frequency in response to changes in the DC voltage from the DC source so that the speed of the AC motor tracks the maximum power available from the DC source. The method may be carried out with an algorithm made up of a series of instructions for sequentially sampling the DC source voltage at a preset sampling interval, comparing the present sampled value of the DC voltage to the prior sampled value, determining whether a change of AC frequency is required based on the comparison of the present to the prior sampled DC voltages, producing a control signal if a change in AC frequency is required, changing the AC frequency in response to the control signal, and continuously repeating the series of instructions.
- A specific sequence of steps illustrating a portion of a particular algorithm for maximum power point tracking is shown in
FIG. 5 , and an illustrative associated wave form and timing diagram is shown inFIG. 6 . This sequence starts with an initial array voltage V0 (the maximum voltage),step 50, at t0. A first voltage sample V1 is taken at time t1,step 51. A first comparison is made, “is V1=V0”,step 52. If the answer to step 52 is Yes (V1=V0), then the voltage is still at its initial value, so return to step 51, and take sample V1 again. If the answer to step 52 is No, then perform a second comparison, “is V1<V0”,step 53. If the answer is Yes, then the voltage has decreased from the initial (rated) value and the available power is less, so the motor speed should decrease. Signal A to driveinput 58 will change the AC frequency of the drive. Also return to step 51 and start a new cycle. If the answer is No, then a second voltage sample V2 is taken,step 54, at t2. (The test “is V1>V0” is not necessary since V0 is the maximum voltage. The comparisons may actually involve some thresholds as discussed withFIG. 4 , but for simplicity to illustrate the basic logic of the process, they are not included.) - The second voltage sample now goes through a sequence of comparisons.
Step 55, “is V2=V0”. If Yes, then the voltage has returned to the initial maximum voltage V0 so the speed must be increased back to its initial speed. Signal B to driveinput 58 will increase the AC frequency, back to the initial frequency. Also return to step 51 and start a new cycle. If No, then “is V2=V”,step 56. If Yes, then the voltage has not changed from the prior value, so return to step 51 and begin a new cycle. If No, then “is V2<V1”,step 57. If Yes, then the array voltage has decreased again, and the available power is even less, so the motor speed should be decreased further. Signal A to driveinput 58 results in a further decrease in motor speed. Also return to step 51 and start a new cycle. If No, then V2>V1, the voltage has increased since the last voltage sample (but not to V0) so the speed should be increased, using signal B. Again return to step 51 and start a new cycle. -
FIG. 6 shows illustrative Voltage (V), Speed (S) and Power (P) wave forms for the process illustrated inFIG. 5 . At the initial time t0, V is at its maximum value V0 so S and P are at their maximums S0 and P0. The voltage sampling and speed adjustment is done at a sequence of times t1, t2, t3 . . . t(n−1), t(n) defined by a sampling interval. At sample time t1, V has decreased to V1 and P to P1 so the speed must be reduced to S1. At sample time t2, the V and P have decreased further to V2 and P2 so the speed must be further reduced to S2. V, S, and P then remain constant up to sample time t(n−1). But at sample time t(n), V and P have increased back to their maximum values V0, P0 so S must be increased back to S0. The method ofFIG. 5 will allow S to track P using V. - Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention which is intended to be limited only by the scope of the appended claims.
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/158,876 US7148650B1 (en) | 2005-06-22 | 2005-06-22 | Maximum power point motor control |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/158,876 US7148650B1 (en) | 2005-06-22 | 2005-06-22 | Maximum power point motor control |
Publications (2)
Publication Number | Publication Date |
---|---|
US7148650B1 US7148650B1 (en) | 2006-12-12 |
US20060290317A1 true US20060290317A1 (en) | 2006-12-28 |
Family
ID=37497269
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/158,876 Expired - Fee Related US7148650B1 (en) | 2005-06-22 | 2005-06-22 | Maximum power point motor control |
Country Status (1)
Country | Link |
---|---|
US (1) | US7148650B1 (en) |
Cited By (57)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009035995A1 (en) * | 2007-09-11 | 2009-03-19 | Efficient Solar Power Systems, Inc. | Distributed maximum power point tracking converter |
US20120181862A1 (en) * | 2009-06-01 | 2012-07-19 | Lars Gertmar | Internal Electrification Scheme For Power Generation Plants |
US9088178B2 (en) | 2006-12-06 | 2015-07-21 | Solaredge Technologies Ltd | Distributed power harvesting systems using DC power sources |
US9112379B2 (en) | 2006-12-06 | 2015-08-18 | Solaredge Technologies Ltd. | Pairing of components in a direct current distributed power generation system |
US9130401B2 (en) | 2006-12-06 | 2015-09-08 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9235228B2 (en) | 2012-03-05 | 2016-01-12 | Solaredge Technologies Ltd. | Direct current link circuit |
US9257896B1 (en) * | 2014-11-28 | 2016-02-09 | Industrial Technology Research Institute | Control circuit of power converter and method for maximum power point tracking |
US9293619B2 (en) | 2011-11-20 | 2016-03-22 | Solexel, Inc. | Smart photovoltaic cells and modules |
US9291696B2 (en) | 2007-12-05 | 2016-03-22 | Solaredge Technologies Ltd. | Photovoltaic system power tracking method |
US9318974B2 (en) | 2014-03-26 | 2016-04-19 | Solaredge Technologies Ltd. | Multi-level inverter with flying capacitor topology |
US9362743B2 (en) | 2008-05-05 | 2016-06-07 | Solaredge Technologies Ltd. | Direct current power combiner |
US9368964B2 (en) | 2006-12-06 | 2016-06-14 | Solaredge Technologies Ltd. | Distributed power system using direct current power sources |
US9401599B2 (en) | 2010-12-09 | 2016-07-26 | Solaredge Technologies Ltd. | Disconnection of a string carrying direct current power |
US9407161B2 (en) | 2007-12-05 | 2016-08-02 | Solaredge Technologies Ltd. | Parallel connected inverters |
US9537445B2 (en) | 2008-12-04 | 2017-01-03 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US9543889B2 (en) | 2006-12-06 | 2017-01-10 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9548619B2 (en) | 2013-03-14 | 2017-01-17 | Solaredge Technologies Ltd. | Method and apparatus for storing and depleting energy |
US9590526B2 (en) | 2006-12-06 | 2017-03-07 | Solaredge Technologies Ltd. | Safety mechanisms, wake up and shutdown methods in distributed power installations |
WO2017066307A1 (en) * | 2015-10-13 | 2017-04-20 | Suntech Drive, Llc | Variable speed maximum power point tracking, solar electric motor controller for induction and permanent magnet ac motors |
US9644993B2 (en) | 2006-12-06 | 2017-05-09 | Solaredge Technologies Ltd. | Monitoring of distributed power harvesting systems using DC power sources |
US9647442B2 (en) | 2010-11-09 | 2017-05-09 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US9673711B2 (en) | 2007-08-06 | 2017-06-06 | Solaredge Technologies Ltd. | Digital average input current control in power converter |
US9680304B2 (en) | 2006-12-06 | 2017-06-13 | Solaredge Technologies Ltd. | Method for distributed power harvesting using DC power sources |
US9685789B2 (en) | 2013-03-14 | 2017-06-20 | The Board Of Trustees Of The Leland Stanford Junior University | Current diversion for power-providing systems |
US9812984B2 (en) | 2012-01-30 | 2017-11-07 | Solaredge Technologies Ltd. | Maximizing power in a photovoltaic distributed power system |
US9819178B2 (en) | 2013-03-15 | 2017-11-14 | Solaredge Technologies Ltd. | Bypass mechanism |
US9831824B2 (en) | 2007-12-05 | 2017-11-28 | SolareEdge Technologies Ltd. | Current sensing on a MOSFET |
WO2017203879A1 (en) * | 2016-05-26 | 2017-11-30 | 日本電産テクノモータ株式会社 | Motor control device and control method, and pump system |
US9853565B2 (en) | 2012-01-30 | 2017-12-26 | Solaredge Technologies Ltd. | Maximized power in a photovoltaic distributed power system |
US9853538B2 (en) | 2007-12-04 | 2017-12-26 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9866098B2 (en) | 2011-01-12 | 2018-01-09 | Solaredge Technologies Ltd. | Serially connected inverters |
US9869701B2 (en) | 2009-05-26 | 2018-01-16 | Solaredge Technologies Ltd. | Theft detection and prevention in a power generation system |
US9876430B2 (en) | 2008-03-24 | 2018-01-23 | Solaredge Technologies Ltd. | Zero voltage switching |
US9923516B2 (en) | 2012-01-30 | 2018-03-20 | Solaredge Technologies Ltd. | Photovoltaic panel circuitry |
US9941813B2 (en) | 2013-03-14 | 2018-04-10 | Solaredge Technologies Ltd. | High frequency multi-level inverter |
US9960667B2 (en) | 2006-12-06 | 2018-05-01 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
US9966766B2 (en) | 2006-12-06 | 2018-05-08 | Solaredge Technologies Ltd. | Battery power delivery module |
US10115841B2 (en) | 2012-06-04 | 2018-10-30 | Solaredge Technologies Ltd. | Integrated photovoltaic panel circuitry |
US10181541B2 (en) | 2011-11-20 | 2019-01-15 | Tesla, Inc. | Smart photovoltaic cells and modules |
US10230310B2 (en) | 2016-04-05 | 2019-03-12 | Solaredge Technologies Ltd | Safety switch for photovoltaic systems |
US10396662B2 (en) | 2011-09-12 | 2019-08-27 | Solaredge Technologies Ltd | Direct current link circuit |
US10673229B2 (en) | 2010-11-09 | 2020-06-02 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US10673222B2 (en) | 2010-11-09 | 2020-06-02 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US10784815B2 (en) | 2013-04-13 | 2020-09-22 | Sigmagen, Inc. | Solar photovoltaic module remote access module switch and real-time temperature monitoring |
US10931119B2 (en) | 2012-01-11 | 2021-02-23 | Solaredge Technologies Ltd. | Photovoltaic module |
US11018623B2 (en) | 2016-04-05 | 2021-05-25 | Solaredge Technologies Ltd. | Safety switch for photovoltaic systems |
US11177663B2 (en) | 2016-04-05 | 2021-11-16 | Solaredge Technologies Ltd. | Chain of power devices |
US11264947B2 (en) | 2007-12-05 | 2022-03-01 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11296650B2 (en) | 2006-12-06 | 2022-04-05 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
US11309832B2 (en) | 2006-12-06 | 2022-04-19 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11569659B2 (en) | 2006-12-06 | 2023-01-31 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11687112B2 (en) | 2006-12-06 | 2023-06-27 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11728768B2 (en) | 2006-12-06 | 2023-08-15 | Solaredge Technologies Ltd. | Pairing of components in a direct current distributed power generation system |
US11735910B2 (en) | 2006-12-06 | 2023-08-22 | Solaredge Technologies Ltd. | Distributed power system using direct current power sources |
US11855231B2 (en) | 2006-12-06 | 2023-12-26 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11881814B2 (en) | 2005-12-05 | 2024-01-23 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11888387B2 (en) | 2006-12-06 | 2024-01-30 | Solaredge Technologies Ltd. | Safety mechanisms, wake up and shutdown methods in distributed power installations |
Families Citing this family (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006137948A2 (en) * | 2004-12-29 | 2006-12-28 | Isg Technologies Llc | Efficiency booster circuit and technique for maximizing power point tracking |
US7309850B2 (en) * | 2005-08-05 | 2007-12-18 | Sinton Consulting, Inc. | Measurement of current-voltage characteristic curves of solar cells and solar modules |
DE102006049779A1 (en) * | 2006-10-21 | 2008-05-21 | Deere & Company, Moline | Überladewagen |
US8625315B2 (en) * | 2008-05-09 | 2014-01-07 | Etm Electromatic Inc | Inverter modulator with variable switching frequency |
US8901411B2 (en) * | 2008-08-27 | 2014-12-02 | General Electric Company | System and method for controlling ramp rate of solar photovoltaic system |
US10282285B2 (en) * | 2008-09-30 | 2019-05-07 | Rockwell Automation Technologies, Inc. | Human interface module for motor drive |
EP2537223A2 (en) * | 2010-02-16 | 2012-12-26 | Danfoss Solar Inverters A/s | A method of operating a maximum power point tracker |
US8338987B2 (en) * | 2010-02-26 | 2012-12-25 | General Electric Company | Power generation frequency control |
US9502904B2 (en) | 2010-03-23 | 2016-11-22 | Eaton Corporation | Power conversion system and method providing maximum efficiency of power conversion for a photovoltaic system, and photovoltaic system employing a photovoltaic array and an energy storage device |
US8716999B2 (en) | 2011-02-10 | 2014-05-06 | Draker, Inc. | Dynamic frequency and pulse-width modulation of dual-mode switching power controllers in photovoltaic arrays |
CN102904474A (en) * | 2011-07-29 | 2013-01-30 | 上海亿福新能源技术有限公司 | Self-regulation tracking method for tracking maximum power point of photovoltaic inverter |
EP2748916B1 (en) | 2011-08-22 | 2016-04-13 | Franklin Electric Company Inc. | Power conversion system |
ITMI20130822A1 (en) * | 2013-05-21 | 2014-11-22 | Gefran Spa | WATER PUMPING SYSTEM USED BY SOLAR ENERGY |
IN2013CH04397A (en) * | 2013-09-27 | 2015-04-03 | Abb Oy | |
IN2013CH04400A (en) * | 2013-09-27 | 2015-04-03 | Abb Oy | |
US9436201B1 (en) | 2015-06-12 | 2016-09-06 | KarmSolar | System and method for maintaining a photovoltaic power source at a maximum power point |
CN108698711A (en) | 2015-10-02 | 2018-10-23 | 富兰克林燃油系统公司 | Solar energy fuelling station |
US11456697B2 (en) * | 2017-11-24 | 2022-09-27 | Delta Electronics India Private Limited | Solar pumping system and a method for operating solar pumping system |
US11303127B2 (en) * | 2019-03-29 | 2022-04-12 | University Of South Carolina | Method for intelligent load management in off-grid AC systems |
CN113623166B (en) * | 2021-07-21 | 2022-07-05 | 深圳天源新能源股份有限公司 | Control method of multi-pump parallel photovoltaic pumping system, inverter and photovoltaic pumping system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4494180A (en) * | 1983-12-02 | 1985-01-15 | Franklin Electric Co., Inc. | Electrical power matching system |
US4538100A (en) * | 1980-03-10 | 1985-08-27 | Creative Technology, Inc. | DC to AC inverter and motor control system |
US4999560A (en) * | 1985-06-11 | 1991-03-12 | Kabushiki Kaisha Toshiba | Electric motor running system employing photovoltaic array |
US5235266A (en) * | 1990-06-02 | 1993-08-10 | Schottel-Werft Josef Becker Gmbh & Co. Kg | Energy-generating plant, particularly propeller-type ship's propulsion plant, including a solar generator |
US5747967A (en) * | 1996-02-22 | 1998-05-05 | Midwest Research Institute | Apparatus and method for maximizing power delivered by a photovoltaic array |
US6232742B1 (en) * | 1994-08-02 | 2001-05-15 | Aerovironment Inc. | Dc/ac inverter apparatus for three-phase and single-phase motors |
US6275403B1 (en) * | 1998-12-31 | 2001-08-14 | Worldwater Corporation | Bias controlled DC to AC converter and systems |
US20050067999A1 (en) * | 2002-01-16 | 2005-03-31 | Masaki Okamura | Voltage converter control apparatus, voltage conversion method, storage medium, program, drive system, and vehicle having the drive system |
US6950323B2 (en) * | 2001-03-09 | 2005-09-27 | Fronius International Gmbh | Method for regulating an inverter system |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3091400B2 (en) * | 1995-09-04 | 2000-09-25 | 大崎電気工業株式会社 | Solar power generation control device |
-
2005
- 2005-06-22 US US11/158,876 patent/US7148650B1/en not_active Expired - Fee Related
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4538100A (en) * | 1980-03-10 | 1985-08-27 | Creative Technology, Inc. | DC to AC inverter and motor control system |
US4494180A (en) * | 1983-12-02 | 1985-01-15 | Franklin Electric Co., Inc. | Electrical power matching system |
US4999560A (en) * | 1985-06-11 | 1991-03-12 | Kabushiki Kaisha Toshiba | Electric motor running system employing photovoltaic array |
US5235266A (en) * | 1990-06-02 | 1993-08-10 | Schottel-Werft Josef Becker Gmbh & Co. Kg | Energy-generating plant, particularly propeller-type ship's propulsion plant, including a solar generator |
US6232742B1 (en) * | 1994-08-02 | 2001-05-15 | Aerovironment Inc. | Dc/ac inverter apparatus for three-phase and single-phase motors |
US5747967A (en) * | 1996-02-22 | 1998-05-05 | Midwest Research Institute | Apparatus and method for maximizing power delivered by a photovoltaic array |
US6275403B1 (en) * | 1998-12-31 | 2001-08-14 | Worldwater Corporation | Bias controlled DC to AC converter and systems |
US6950323B2 (en) * | 2001-03-09 | 2005-09-27 | Fronius International Gmbh | Method for regulating an inverter system |
US20050067999A1 (en) * | 2002-01-16 | 2005-03-31 | Masaki Okamura | Voltage converter control apparatus, voltage conversion method, storage medium, program, drive system, and vehicle having the drive system |
Cited By (134)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11881814B2 (en) | 2005-12-05 | 2024-01-23 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11309832B2 (en) | 2006-12-06 | 2022-04-19 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11063440B2 (en) | 2006-12-06 | 2021-07-13 | Solaredge Technologies Ltd. | Method for distributed power harvesting using DC power sources |
US9112379B2 (en) | 2006-12-06 | 2015-08-18 | Solaredge Technologies Ltd. | Pairing of components in a direct current distributed power generation system |
US9130401B2 (en) | 2006-12-06 | 2015-09-08 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11962243B2 (en) | 2006-12-06 | 2024-04-16 | Solaredge Technologies Ltd. | Method for distributed power harvesting using DC power sources |
US11594882B2 (en) | 2006-12-06 | 2023-02-28 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11002774B2 (en) | 2006-12-06 | 2021-05-11 | Solaredge Technologies Ltd. | Monitoring of distributed power harvesting systems using DC power sources |
US11031861B2 (en) | 2006-12-06 | 2021-06-08 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
US11043820B2 (en) | 2006-12-06 | 2021-06-22 | Solaredge Technologies Ltd. | Battery power delivery module |
US11888387B2 (en) | 2006-12-06 | 2024-01-30 | Solaredge Technologies Ltd. | Safety mechanisms, wake up and shutdown methods in distributed power installations |
US11594881B2 (en) | 2006-12-06 | 2023-02-28 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9368964B2 (en) | 2006-12-06 | 2016-06-14 | Solaredge Technologies Ltd. | Distributed power system using direct current power sources |
US11073543B2 (en) | 2006-12-06 | 2021-07-27 | Solaredge Technologies Ltd. | Monitoring of distributed power harvesting systems using DC power sources |
US10673253B2 (en) | 2006-12-06 | 2020-06-02 | Solaredge Technologies Ltd. | Battery power delivery module |
US11183922B2 (en) | 2006-12-06 | 2021-11-23 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9543889B2 (en) | 2006-12-06 | 2017-01-10 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US10637393B2 (en) | 2006-12-06 | 2020-04-28 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9590526B2 (en) | 2006-12-06 | 2017-03-07 | Solaredge Technologies Ltd. | Safety mechanisms, wake up and shutdown methods in distributed power installations |
US11855231B2 (en) | 2006-12-06 | 2023-12-26 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11735910B2 (en) | 2006-12-06 | 2023-08-22 | Solaredge Technologies Ltd. | Distributed power system using direct current power sources |
US9644993B2 (en) | 2006-12-06 | 2017-05-09 | Solaredge Technologies Ltd. | Monitoring of distributed power harvesting systems using DC power sources |
US11728768B2 (en) | 2006-12-06 | 2023-08-15 | Solaredge Technologies Ltd. | Pairing of components in a direct current distributed power generation system |
US10447150B2 (en) | 2006-12-06 | 2019-10-15 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9680304B2 (en) | 2006-12-06 | 2017-06-13 | Solaredge Technologies Ltd. | Method for distributed power harvesting using DC power sources |
US11296650B2 (en) | 2006-12-06 | 2022-04-05 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
US11687112B2 (en) | 2006-12-06 | 2023-06-27 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11682918B2 (en) | 2006-12-06 | 2023-06-20 | Solaredge Technologies Ltd. | Battery power delivery module |
US10230245B2 (en) | 2006-12-06 | 2019-03-12 | Solaredge Technologies Ltd | Battery power delivery module |
US11658482B2 (en) | 2006-12-06 | 2023-05-23 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11598652B2 (en) | 2006-12-06 | 2023-03-07 | Solaredge Technologies Ltd. | Monitoring of distributed power harvesting systems using DC power sources |
US11476799B2 (en) | 2006-12-06 | 2022-10-18 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9853490B2 (en) | 2006-12-06 | 2017-12-26 | Solaredge Technologies Ltd. | Distributed power system using direct current power sources |
US11594880B2 (en) | 2006-12-06 | 2023-02-28 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11569660B2 (en) | 2006-12-06 | 2023-01-31 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US10097007B2 (en) | 2006-12-06 | 2018-10-09 | Solaredge Technologies Ltd. | Method for distributed power harvesting using DC power sources |
US11569659B2 (en) | 2006-12-06 | 2023-01-31 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11961922B2 (en) | 2006-12-06 | 2024-04-16 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US9088178B2 (en) | 2006-12-06 | 2015-07-21 | Solaredge Technologies Ltd | Distributed power harvesting systems using DC power sources |
US9966766B2 (en) | 2006-12-06 | 2018-05-08 | Solaredge Technologies Ltd. | Battery power delivery module |
US9960731B2 (en) | 2006-12-06 | 2018-05-01 | Solaredge Technologies Ltd. | Pairing of components in a direct current distributed power generation system |
US9960667B2 (en) | 2006-12-06 | 2018-05-01 | Solaredge Technologies Ltd. | System and method for protection during inverter shutdown in distributed power installations |
US9948233B2 (en) | 2006-12-06 | 2018-04-17 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11575261B2 (en) | 2006-12-06 | 2023-02-07 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11579235B2 (en) | 2006-12-06 | 2023-02-14 | Solaredge Technologies Ltd. | Safety mechanisms, wake up and shutdown methods in distributed power installations |
US11575260B2 (en) | 2006-12-06 | 2023-02-07 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11594968B2 (en) | 2007-08-06 | 2023-02-28 | Solaredge Technologies Ltd. | Digital average input current control in power converter |
US10516336B2 (en) | 2007-08-06 | 2019-12-24 | Solaredge Technologies Ltd. | Digital average input current control in power converter |
US9673711B2 (en) | 2007-08-06 | 2017-06-06 | Solaredge Technologies Ltd. | Digital average input current control in power converter |
US10116217B2 (en) | 2007-08-06 | 2018-10-30 | Solaredge Technologies Ltd. | Digital average input current control in power converter |
WO2009035995A1 (en) * | 2007-09-11 | 2009-03-19 | Efficient Solar Power Systems, Inc. | Distributed maximum power point tracking converter |
US9853538B2 (en) | 2007-12-04 | 2017-12-26 | Solaredge Technologies Ltd. | Distributed power harvesting systems using DC power sources |
US11183923B2 (en) | 2007-12-05 | 2021-11-23 | Solaredge Technologies Ltd. | Parallel connected inverters |
US10693415B2 (en) | 2007-12-05 | 2020-06-23 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11894806B2 (en) | 2007-12-05 | 2024-02-06 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11693080B2 (en) | 2007-12-05 | 2023-07-04 | Solaredge Technologies Ltd. | Parallel connected inverters |
US9291696B2 (en) | 2007-12-05 | 2016-03-22 | Solaredge Technologies Ltd. | Photovoltaic system power tracking method |
US9831824B2 (en) | 2007-12-05 | 2017-11-28 | SolareEdge Technologies Ltd. | Current sensing on a MOSFET |
US9979280B2 (en) | 2007-12-05 | 2018-05-22 | Solaredge Technologies Ltd. | Parallel connected inverters |
US9407161B2 (en) | 2007-12-05 | 2016-08-02 | Solaredge Technologies Ltd. | Parallel connected inverters |
US11183969B2 (en) | 2007-12-05 | 2021-11-23 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US11264947B2 (en) | 2007-12-05 | 2022-03-01 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US10644589B2 (en) | 2007-12-05 | 2020-05-05 | Solaredge Technologies Ltd. | Parallel connected inverters |
US9876430B2 (en) | 2008-03-24 | 2018-01-23 | Solaredge Technologies Ltd. | Zero voltage switching |
US11424616B2 (en) | 2008-05-05 | 2022-08-23 | Solaredge Technologies Ltd. | Direct current power combiner |
US10468878B2 (en) | 2008-05-05 | 2019-11-05 | Solaredge Technologies Ltd. | Direct current power combiner |
US9362743B2 (en) | 2008-05-05 | 2016-06-07 | Solaredge Technologies Ltd. | Direct current power combiner |
US9537445B2 (en) | 2008-12-04 | 2017-01-03 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US10461687B2 (en) | 2008-12-04 | 2019-10-29 | Solaredge Technologies Ltd. | Testing of a photovoltaic panel |
US9869701B2 (en) | 2009-05-26 | 2018-01-16 | Solaredge Technologies Ltd. | Theft detection and prevention in a power generation system |
US11867729B2 (en) | 2009-05-26 | 2024-01-09 | Solaredge Technologies Ltd. | Theft detection and prevention in a power generation system |
US10969412B2 (en) | 2009-05-26 | 2021-04-06 | Solaredge Technologies Ltd. | Theft detection and prevention in a power generation system |
US20120181862A1 (en) * | 2009-06-01 | 2012-07-19 | Lars Gertmar | Internal Electrification Scheme For Power Generation Plants |
US9300131B2 (en) * | 2009-06-01 | 2016-03-29 | Abb Research Ltd. | Internal electrification scheme for power generation plants |
US10673229B2 (en) | 2010-11-09 | 2020-06-02 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US10673222B2 (en) | 2010-11-09 | 2020-06-02 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US10931228B2 (en) | 2010-11-09 | 2021-02-23 | Solaredge Technologies Ftd. | Arc detection and prevention in a power generation system |
US11489330B2 (en) | 2010-11-09 | 2022-11-01 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US9647442B2 (en) | 2010-11-09 | 2017-05-09 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US11070051B2 (en) | 2010-11-09 | 2021-07-20 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US11349432B2 (en) | 2010-11-09 | 2022-05-31 | Solaredge Technologies Ltd. | Arc detection and prevention in a power generation system |
US9401599B2 (en) | 2010-12-09 | 2016-07-26 | Solaredge Technologies Ltd. | Disconnection of a string carrying direct current power |
US9935458B2 (en) | 2010-12-09 | 2018-04-03 | Solaredge Technologies Ltd. | Disconnection of a string carrying direct current power |
US11271394B2 (en) | 2010-12-09 | 2022-03-08 | Solaredge Technologies Ltd. | Disconnection of a string carrying direct current power |
US9866098B2 (en) | 2011-01-12 | 2018-01-09 | Solaredge Technologies Ltd. | Serially connected inverters |
US10666125B2 (en) | 2011-01-12 | 2020-05-26 | Solaredge Technologies Ltd. | Serially connected inverters |
US11205946B2 (en) | 2011-01-12 | 2021-12-21 | Solaredge Technologies Ltd. | Serially connected inverters |
US10396662B2 (en) | 2011-09-12 | 2019-08-27 | Solaredge Technologies Ltd | Direct current link circuit |
US9293619B2 (en) | 2011-11-20 | 2016-03-22 | Solexel, Inc. | Smart photovoltaic cells and modules |
US10181541B2 (en) | 2011-11-20 | 2019-01-15 | Tesla, Inc. | Smart photovoltaic cells and modules |
US10931119B2 (en) | 2012-01-11 | 2021-02-23 | Solaredge Technologies Ltd. | Photovoltaic module |
US9923516B2 (en) | 2012-01-30 | 2018-03-20 | Solaredge Technologies Ltd. | Photovoltaic panel circuitry |
US9853565B2 (en) | 2012-01-30 | 2017-12-26 | Solaredge Technologies Ltd. | Maximized power in a photovoltaic distributed power system |
US10608553B2 (en) | 2012-01-30 | 2020-03-31 | Solaredge Technologies Ltd. | Maximizing power in a photovoltaic distributed power system |
US11183968B2 (en) | 2012-01-30 | 2021-11-23 | Solaredge Technologies Ltd. | Photovoltaic panel circuitry |
US11620885B2 (en) | 2012-01-30 | 2023-04-04 | Solaredge Technologies Ltd. | Photovoltaic panel circuitry |
US9812984B2 (en) | 2012-01-30 | 2017-11-07 | Solaredge Technologies Ltd. | Maximizing power in a photovoltaic distributed power system |
US10381977B2 (en) | 2012-01-30 | 2019-08-13 | Solaredge Technologies Ltd | Photovoltaic panel circuitry |
US11929620B2 (en) | 2012-01-30 | 2024-03-12 | Solaredge Technologies Ltd. | Maximizing power in a photovoltaic distributed power system |
US10992238B2 (en) | 2012-01-30 | 2021-04-27 | Solaredge Technologies Ltd. | Maximizing power in a photovoltaic distributed power system |
US9639106B2 (en) | 2012-03-05 | 2017-05-02 | Solaredge Technologies Ltd. | Direct current link circuit |
US10007288B2 (en) | 2012-03-05 | 2018-06-26 | Solaredge Technologies Ltd. | Direct current link circuit |
US9235228B2 (en) | 2012-03-05 | 2016-01-12 | Solaredge Technologies Ltd. | Direct current link circuit |
US10115841B2 (en) | 2012-06-04 | 2018-10-30 | Solaredge Technologies Ltd. | Integrated photovoltaic panel circuitry |
US11177768B2 (en) | 2012-06-04 | 2021-11-16 | Solaredge Technologies Ltd. | Integrated photovoltaic panel circuitry |
US9548619B2 (en) | 2013-03-14 | 2017-01-17 | Solaredge Technologies Ltd. | Method and apparatus for storing and depleting energy |
US11742777B2 (en) | 2013-03-14 | 2023-08-29 | Solaredge Technologies Ltd. | High frequency multi-level inverter |
US9941813B2 (en) | 2013-03-14 | 2018-04-10 | Solaredge Technologies Ltd. | High frequency multi-level inverter |
US10778025B2 (en) | 2013-03-14 | 2020-09-15 | Solaredge Technologies Ltd. | Method and apparatus for storing and depleting energy |
US9685789B2 (en) | 2013-03-14 | 2017-06-20 | The Board Of Trustees Of The Leland Stanford Junior University | Current diversion for power-providing systems |
US11545912B2 (en) | 2013-03-14 | 2023-01-03 | Solaredge Technologies Ltd. | High frequency multi-level inverter |
US9819178B2 (en) | 2013-03-15 | 2017-11-14 | Solaredge Technologies Ltd. | Bypass mechanism |
US11424617B2 (en) | 2013-03-15 | 2022-08-23 | Solaredge Technologies Ltd. | Bypass mechanism |
US10651647B2 (en) | 2013-03-15 | 2020-05-12 | Solaredge Technologies Ltd. | Bypass mechanism |
US11888441B2 (en) | 2013-04-13 | 2024-01-30 | Sigmagen, Inc. | Solar photovoltaic module remote access module switch and real-time temperature monitoring |
US10784815B2 (en) | 2013-04-13 | 2020-09-22 | Sigmagen, Inc. | Solar photovoltaic module remote access module switch and real-time temperature monitoring |
US10886831B2 (en) | 2014-03-26 | 2021-01-05 | Solaredge Technologies Ltd. | Multi-level inverter |
US9318974B2 (en) | 2014-03-26 | 2016-04-19 | Solaredge Technologies Ltd. | Multi-level inverter with flying capacitor topology |
US11632058B2 (en) | 2014-03-26 | 2023-04-18 | Solaredge Technologies Ltd. | Multi-level inverter |
US11296590B2 (en) | 2014-03-26 | 2022-04-05 | Solaredge Technologies Ltd. | Multi-level inverter |
US11855552B2 (en) | 2014-03-26 | 2023-12-26 | Solaredge Technologies Ltd. | Multi-level inverter |
US10886832B2 (en) | 2014-03-26 | 2021-01-05 | Solaredge Technologies Ltd. | Multi-level inverter |
US9257896B1 (en) * | 2014-11-28 | 2016-02-09 | Industrial Technology Research Institute | Control circuit of power converter and method for maximum power point tracking |
US10931220B2 (en) * | 2015-10-13 | 2021-02-23 | Premier Energy Holdings, Inc. | Variable speed maximum power point tracking, solar electric motor controller for induction and permanent magnet AC motors |
IL258401A (en) * | 2015-10-13 | 2018-05-31 | Suntech Drive Llc | Variable speed maximum power point tracking, solar electric motor controller for induction and permanent magnet ac motors |
WO2017066307A1 (en) * | 2015-10-13 | 2017-04-20 | Suntech Drive, Llc | Variable speed maximum power point tracking, solar electric motor controller for induction and permanent magnet ac motors |
CN108431719A (en) * | 2015-10-13 | 2018-08-21 | 尚德驱动器有限责任公司 | For incuding, the speed change MPPT maximum power point tracking of permanent magnetism AC motor, solar energy electric machine controller |
US20180278193A1 (en) * | 2015-10-13 | 2018-09-27 | Suntech Drive, Llc | Variable speed maximum power point tracking, solar electric motor controller for induction and permanent magnet ac motors |
US11177663B2 (en) | 2016-04-05 | 2021-11-16 | Solaredge Technologies Ltd. | Chain of power devices |
US11870250B2 (en) | 2016-04-05 | 2024-01-09 | Solaredge Technologies Ltd. | Chain of power devices |
US11018623B2 (en) | 2016-04-05 | 2021-05-25 | Solaredge Technologies Ltd. | Safety switch for photovoltaic systems |
US11201476B2 (en) | 2016-04-05 | 2021-12-14 | Solaredge Technologies Ltd. | Photovoltaic power device and wiring |
US10230310B2 (en) | 2016-04-05 | 2019-03-12 | Solaredge Technologies Ltd | Safety switch for photovoltaic systems |
WO2017203879A1 (en) * | 2016-05-26 | 2017-11-30 | 日本電産テクノモータ株式会社 | Motor control device and control method, and pump system |
Also Published As
Publication number | Publication date |
---|---|
US7148650B1 (en) | 2006-12-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7148650B1 (en) | Maximum power point motor control | |
US20070290651A1 (en) | Solar power control using irradiance | |
JP2810630B2 (en) | Solar cell power control device, power control system, power control method, and voltage / current output characteristic measurement method | |
US7126294B2 (en) | Method and device for controlling photovoltaic inverter, and feed water device | |
Talbi et al. | A high-performance control scheme for photovoltaic pumping system under sudden irradiance and load changes | |
US5838148A (en) | Power control method and apparatus for battery power supply and battery power supply system | |
US9143082B2 (en) | Solar power generation system, control device used for solar power generation system, and control method and program for same | |
RU2528621C2 (en) | System and method for dynamic control of active power at load | |
Muljadi | PV water pumping with a peak-power tracker using a simple six-step square-wave inverter | |
US8450883B2 (en) | Maximum power point tracking control apparatus for solar battery | |
US20110309875A1 (en) | Converter lifetime improvement method for doubly fed induction generator | |
TW201211724A (en) | Ar power system and control system | |
CN105191045B (en) | For DC input powers to be converted into the method and apparatus of AC output powers | |
US20130099495A1 (en) | Power control method and system for wind generating set | |
JP6280976B2 (en) | Inverter | |
US20180226803A1 (en) | Control device for power converter, control program and power conversion device | |
US6275403B1 (en) | Bias controlled DC to AC converter and systems | |
KR20120077865A (en) | Maximum power point tracking method based on scanning of pv array and system thereof | |
CN106200752B (en) | A kind of photovoltaic array under local shadow maximal power tracing System with Sliding Mode Controller | |
JP3949350B2 (en) | Interconnection device | |
JPH0833211A (en) | Inverter | |
JP2002108466A (en) | Device and method for controlling power and power generator | |
JP3359206B2 (en) | Battery power control device | |
JPH09258838A (en) | Maximum electric power control method for photovolatic power generation system | |
JP2014230453A (en) | Inverter controller |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: WORLDWATER & POWER CORP., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MCNULTY, THOMAS CHARLES;HORTA, JUAN CARLOS;PLAISIME, JOACINE;REEL/FRAME:016719/0153 Effective date: 20050622 |
|
AS | Assignment |
Owner name: WORLDWATER & POWER CORP., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MCNULTY, THOMAS CHARLES;HORTA, JUAN CARLOS;PLAISIME, JOACINE;REEL/FRAME:021170/0211;SIGNING DATES FROM 20050602 TO 20050622 |
|
AS | Assignment |
Owner name: ENTECH SOLAR, INC., NEW JERSEY Free format text: CHANGE OF NAME;ASSIGNOR:WORLWATER & SOLAR TECHNOLOGIES CORP.;REEL/FRAME:022117/0904 Effective date: 20081113 Owner name: WORLDWATER & SOLAR TECHNOLOGIES CORP., NEW JERSEY Free format text: MERGER;ASSIGNOR:WORLDWATER AND POWER CORP.;REEL/FRAME:022117/0800 Effective date: 20070828 |
|
AS | Assignment |
Owner name: ENTECH SOLAR, INC., NEW JERSEY Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE ASSIGNOR PREVIOUSLY RECORDED ON REEL 022117 FRAME 0904;ASSIGNOR:WORLDWATER & SOLAR TECHNOLOGIES CORP.;REEL/FRAME:022137/0941 Effective date: 20081113 |
|
REMI | Maintenance fee reminder mailed | ||
AS | Assignment |
Owner name: KELLY, QUENTIN T., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ENTECH SOLAR, INC.;REEL/FRAME:024741/0406 Effective date: 20100712 |
|
AS | Assignment |
Owner name: WORLDWATER & SOLAR TECHNOLOGIES, INC., NEW JERSEY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KELLY, QUENTIN T.;REEL/FRAME:025039/0801 Effective date: 20100823 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
SULP | Surcharge for late payment | ||
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20141212 |