JPWO2020152830A1 - Control method of photovoltaic power generation drive system and photovoltaic power generation drive system - Google Patents

Abstract

The solar power generation drive system (1) has an inverter circuit unit (4) that converts the DC voltage output by the solar panel (2) into an AC voltage according to a pulse signal and outputs the AC voltage, and a preset AC voltage. Frequency — The frequency limit value calculation unit (13) that calculates the limit value of the output frequency, which is the frequency of the AC voltage, based on the voltage characteristics and the value of the DC voltage output by the solar panel (2), and the command value of the output frequency. It is provided with an output frequency calculation unit (15) that calculates and outputs a pulse signal based on a command value or a limit value to the inverter circuit unit (4).

Description

The present invention relates to a photovoltaic power generation drive system that drives a load by using electric energy obtained by power generation by a solar panel, and a control method for the photovoltaic power generation drive system.

The photovoltaic power generation drive system that drives the motor, which is the load, adjusts the rotation speed of the motor so that the output power of the solar panel is equal to or higher than the maximum power point of the solar panel in order to drive the motor stably and continuously. , Control the output power of the solar panel. The maximum power point changes due to environmental changes such as changes in the amount of sunlight or changes in temperature at the location where the solar panels are installed. If the solar output power falls below the maximum power point, the motor will malfunction. The solar output power is the output power of the solar panel.

In Patent Document 1, the margin up to the maximum power point of the solar output power is estimated based on the fluctuation of the output voltage of the solar panel when the rotation speed of the motor is repeatedly changed, and the output voltage of the solar panel is calculated. It is disclosed that adjustments are made to make the voltage higher than the maximum power point voltage. According to the technology of Patent Document 1, the output voltage of the solar panel is higher than the voltage of the maximum power point, and the difference between the output voltage and the voltage of the maximum power point is maintained within an allowable range. The power generation drive system can reduce the malfunction of the motor even when the solar output power continuously changes due to the environmental change.

Japanese Patent No. 6105733

According to the technology of Patent Document 1, in the photovoltaic power generation drive system, until the output voltage of the solar panel is higher than the voltage of the maximum power point and the deviation between the voltage of the maximum power point and the output voltage is within an allowable range. Adjustments are made to detect the output voltage of the solar panel by repeatedly changing the rotation speed of the motor. For this reason, the photovoltaic power generation drive system has a problem that it takes time for the output voltage of the solar panel to be maintained at an appropriate value.

Further, according to the technique of Patent Document 1, the photovoltaic power generation drive system needs to repeatedly change the rotation speed of the motor at a preset timing in order to detect the change of the maximum power point. Therefore, even if there is no change in the solar output power and adjustment for controlling the solar output power is unnecessary, the photovoltaic power generation drive system needs to be adjusted to repeatedly change the rotation speed at the relevant timing. Therefore, there is a problem that the motor cannot be driven stably.

The present invention has been made in view of the above, and is a photovoltaic power generation drive system capable of shortening the time required for adjustment for controlling the output power of a solar panel and enabling stable drive of a load. The purpose is to get.

In order to solve the above-mentioned problems and achieve the object, the photovoltaic power generation drive system according to the present invention is a photovoltaic power generation drive system that drives a load by using the electric power output from the solar panel. The solar power generation drive system according to the present invention has an inverter circuit unit that converts a DC voltage output by a solar panel into an AC voltage according to a pulse signal and outputs an AC voltage, and a preset frequency-voltage characteristic of the AC voltage. The frequency limit value calculation unit that calculates the limit value of the output frequency, which is the frequency of the AC voltage, based on the value of the DC voltage output by the solar panel, and the command value of the output frequency are calculated and based on the command value or the limit value. It includes an output frequency calculation unit that outputs a pulse signal to the inverter circuit unit.

The photovoltaic power generation drive system according to the present invention has an effect that the time required for adjustment for controlling the output power of the solar panel can be shortened and the load can be stably driven.

The figure which shows the schematic structure of the photovoltaic power generation drive system which concerns on Embodiment 1 of this invention. The figure which shows the solar panel, the drive device and the motor which make up the photovoltaic power generation drive system shown in FIG. The figure explaining the relationship between the DC voltage output by the solar panel shown in FIG. 2 and the output frequency of an inverter circuit part. FIG. 2 is a diagram showing an example of the relationship between the frequency limit value calculated by the frequency limit value calculation unit of the drive device shown in FIG. The figure which shows another example of the relationship between the frequency limit value and AC voltage calculated by the frequency limit value calculation part of the drive device shown in FIG. A flowchart showing a procedure of operation by the control unit of the drive device shown in FIG. The figure which shows the hardware composition in the case where the function of the control part which the drive device shown in FIG. 2 is realized by using the dedicated hardware. The figure which shows the hardware configuration in the case where the function of the control part which the drive | driving device has shown in FIG. 2 is realized by using a processor.

Hereinafter, the photovoltaic power generation drive system and the control method of the photovoltaic power generation drive system according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

Embodiment 1.
FIG. 1 is a diagram showing a schematic configuration of a photovoltaic power generation drive system 1 according to a first embodiment of the present invention. FIG. 2 is a diagram showing a solar panel 2, a drive device 5, and a motor 6 constituting the photovoltaic power generation drive system 1 shown in FIG. The photovoltaic power generation drive system 1 uses the electric power output from the solar panel 2 to drive the motor 6, which is a load. The motor 6 is, for example, an induction motor. The photovoltaic power generation drive system 1 includes a drive device 5 that converts the DC voltage supplied by the solar panel 2 into an AC voltage and outputs the AC voltage to the motor 6.

The drive device 5 includes a capacitor 3 that stores the DC voltage supplied by the solar panel 2, and an inverter circuit unit 4 that converts the DC voltage stored in the capacitor 3 into an AC voltage and outputs the AC voltage. Further, the drive device 5 includes a voltage detection unit 10 that detects the DC voltage stored in the capacitor 3, a current detection unit 11 that detects the current on the output side of the inverter circuit unit 4, and a control unit that controls the drive device 5. Has 20 and. Note that FIG. 2 shows the functional configuration of the control unit 20.

The inverter circuit unit 4 converts the DC voltage supplied by the solar panel 2 into an AC voltage having a frequency corresponding to the motor 6 according to the pulse signal output by the control unit 20. The inverter circuit unit 4 applies the converted AC voltage to the motor 6. Specifically, the inverter circuit unit 4 controls the frequency and voltage level of the AC voltage by VVVF (Variable Voltage Variable Frequency) control.

The current detection unit 11 detects the phase currents of the U phase, V phase, and W phase output by the inverter circuit unit 4. The general term for the phase current is referred to as an output current. The control unit 20 calculates the command value of the output frequency based on the value of the DC voltage detected by the voltage detection unit 10 and the value of the output current detected by the current detection unit 11. The output frequency is the frequency of the AC voltage output by the inverter circuit unit 4. The control unit 20 outputs a pulse signal based on the calculated command value or the frequency limit value described later to the inverter circuit unit 4. The pulse signal is a signal that has undergone pulse width modulation (PWM).

The control unit 20 feedback-controls the inverter circuit unit 4. The control unit 20 monitors the detection result of the DC voltage by the voltage detection unit 10, and if there is a DC voltage drop, the control unit 20 determines whether or not the drop is an abnormal voltage drop. Has. Further, the control unit 20 includes a frequency limit value calculation unit 13 that calculates a frequency limit value that is an output frequency limit value, and an acceleration / deceleration interruption determination unit 14 that determines interruption and restart of acceleration or deceleration of the rotation of the motor 6. And an output frequency calculation unit 15 for calculating a command value of the output frequency. Each functional unit included in the control unit 20 is realized by executing a control program, which is a program for executing the control method of the photovoltaic power generation drive system 1 of the first embodiment, by using hardware.

The abnormal voltage drop determination unit 12 detects an abnormality in the voltage drop based on the change in the value of the DC voltage detected by the voltage detection unit 10. Specifically, the abnormal voltage drop determination unit 12 has an abnormal voltage drop when the decrease in the DC voltage value within a preset time from the start of the voltage drop is a decrease equal to or greater than the threshold value. Judge. Further, the abnormal voltage drop determination unit 12 determines that the DC voltage is normal if the value of the DC voltage does not decrease by the threshold value or more within the set time.

The abnormal voltage drop determination unit 12 outputs 1-bit information indicating whether or not there is an abnormal voltage drop. The signal when it is determined that there is an abnormal voltage drop is "1", and the signal when it is determined that there is a normal voltage drop is "0". The signal output by the abnormal voltage drop determination unit 12 may be any signal that can identify whether or not there is an abnormal voltage drop, and is not limited to "0" and "1".

The frequency limit value calculation unit 13 calculates the frequency limit value based on the DC voltage value detected by the voltage detection unit 10 and the V / F characteristic which is the frequency-voltage characteristic of the AC voltage set in advance. The V / F characteristic can be said to be a characteristic in which the output voltage changes with respect to a change in the output frequency. Further, when "1" is output from the abnormal voltage drop determination unit 12 to the frequency limit value calculation unit 13, the frequency limit value calculation unit 13 performs subtraction correction of the calculated frequency limit value. When the output from the abnormal voltage drop determination unit 12 to the frequency limit value calculation unit 13 is "0", the frequency limit value calculation unit 13 does not perform subtraction correction of the calculated frequency limit value.

FIG. 3 is a diagram illustrating the relationship between the DC voltage output by the solar panel 2 shown in FIG. 2 and the output frequency of the inverter circuit unit 4. The vertical axis of the graph shown in the upper part of FIG. 3 represents the DC voltage "V _D". The vertical axis of the graph shown in the lower part of FIG. 3 represents the frequency limit value “f”. The horizontal axis of these two graphs represents time.

As described above, the frequency limit value calculation unit 13 calculates the frequency limit value based on the value of the DC voltage. If the DC voltage drop starts at time t1 and the decrease in the DC voltage value is equal to or greater than the threshold ΔV _TH at time t2 before the set time Δt elapses from time t1, the abnormal voltage drop determination unit 12 Determines that the voltage drop started at time t1 is an abnormal voltage drop, and outputs "1" indicating the determination result to the frequency limit value calculation unit 13. Since "1" is output from the abnormal voltage drop determination unit 12 to the frequency limit value calculation unit 13, the frequency limit value calculation unit 13 subtracts the frequency limit value calculated based on the DC voltage value by Δf. Make corrections. From the time t2 until the set time Δt elapses, the frequency limit value calculation unit 13 sets the frequency limit value as the value after subtraction correction.

If there is no decrease in the DC voltage value equal to or greater than the threshold value ΔV _TH before the set time Δt elapses after the time t2, the abnormal voltage drop determination unit 12 determines that the DC voltage at the time t3 is normal. , The output to the frequency limit value calculation unit 13 is set to "0". Since the output from the abnormal voltage drop determination unit 12 to the frequency limit value calculation unit 13 is set to "0", the frequency limit value calculation unit 13 subtracts and corrects the frequency limit value calculated based on the DC voltage value. Do not do. The photovoltaic power generation drive system 1 can suppress malfunction of the motor 6 due to the abnormal voltage drop by performing subtraction correction of the frequency limit value when there is an abnormal voltage drop.

Here, a specific calculation method of the frequency limit value by the frequency limit value calculation unit 13 will be described. The frequency limit value calculation unit 13 calculates the frequency limit value based on the V / F characteristic suitable for the application or load characteristic of the motor 6. The photovoltaic power generation drive system 1 limits the output frequency by a frequency limit value based on the V / F characteristics so that the output voltage of the inverter circuit unit 4 does not become a voltage higher than the DC voltage stored in the capacitor 3. As a result, the photovoltaic power generation drive system 1 can prevent the inverter output power, which is the output power of the inverter circuit unit 4, from becoming equal to or more than the solar output power, which is the output power of the solar panel 2.

Two examples of the frequency limit value calculation method will be described below. The calculation method according to the first example is a calculation method of the frequency limit value when the application of the motor 6 is a constant torque load application. The frequency limit value calculation unit 13 calculates f _L1 , which is a frequency limit value for constant torque load applications, based on the V / F characteristics represented by the following equation (1). In the formula (1) and each of the formulas described below, V _D is the DC voltage which is the detection result by the voltage detection unit 10, f0 is the base frequency of the inverter circuit unit 4, and V _f0 is the base frequency voltage of the inverter circuit unit 4, V. _S is the output start voltage of the inverter circuit unit 4, and f _S is the output start frequency of the inverter circuit unit 4. The output start voltage is the output voltage of the inverter circuit unit 4 at the start of driving the motor 6, and is the lower limit voltage at which the inverter circuit unit 4 can normally operate in driving the motor 6. The output start frequency is the frequency of the output voltage of the inverter circuit unit 4 at the start of driving the motor 6, and is the output frequency at the lower limit voltage. The frequency limit value calculation unit 13 calculates the frequency limit value by substituting each value of the DC voltage, the base frequency, the base frequency voltage, the output start voltage, and the output start frequency into the equation (1).

FIG. 4 is a diagram showing an example of the relationship between the frequency limit value calculated by the frequency limit value calculation unit 13 of the drive device 5 shown in FIG. 2 and the AC voltage. The vertical axis of the graph shown in FIG. 4 represents the frequency limit value “f _L1 ” for constant torque load applications. The horizontal axis of the graph represents the AC voltage " _VA ". In FIG. 4, the relationship between the frequency limit value and the AC voltage is represented by a linear graph. The graph shown in FIG. 4 shows the V / F characteristics when the application of the motor 6 is a constant torque load application.

The calculation method according to the second example is a calculation method of the frequency limit value when the application of the motor 6 is a reduced torque load application. The frequency limit value calculation unit 13 calculates f _L2 , which is a frequency limit value for reduced torque load applications, based on the V / F characteristics represented by the following equation (2). The frequency limit value calculation unit 13 calculates the frequency limit value by substituting each value of the DC voltage, the base frequency, the base frequency voltage, the output start voltage, and the output start frequency into the equation (2).

FIG. 5 is a diagram showing another example of the relationship between the frequency limit value calculated by the frequency limit value calculation unit 13 included in the drive device 5 shown in FIG. 2 and the AC voltage. The vertical axis of the graph shown in FIG. 5 represents the frequency limit value “f _L2 ” for reduced torque load applications. The horizontal axis of the graph represents " _VA ", which is an AC voltage. In FIG. 5, the relationship between the frequency limit value and the AC voltage is represented by a curve graph. The graph shown in FIG. 5 shows the V / F characteristics when the application of the motor 6 is a reduced torque load application. As described above, the frequency limit value calculation unit 13 can change the frequency limit value calculation method according to the application of the motor 6 or the load characteristics.

The acceleration / deceleration interruption determination unit 14 determines whether to suspend or restart the acceleration or deceleration of the rotation of the motor 6 based on the solar output power and the inverter output power. The drive device 5 suspends and restarts acceleration / deceleration according to a determination by the acceleration / deceleration interruption determination unit 14, thereby suppressing an increase in inverter output power due to the effect of a temporary load increase generated during acceleration / deceleration of the motor 6. .. By suppressing the increase in the inverter output power, the drive device 5 suppresses the occurrence of a voltage drop of the DC voltage due to the inverter output power becoming equal to or higher than the solar output power. As a result, the drive device 5 can suppress malfunction of the motor 6 during acceleration / deceleration of the motor 6.

Specifically, the acceleration / deceleration interruption determination unit 14 can obtain the solar output power by the following equation (3). The acceleration / deceleration interruption determination unit 14 can obtain the inverter output power by the following equation (4). In the formula (3), _{P S} is the solar power _{output, P S0} is a solar reference output power. The solar reference output power is the solar output voltage when the output voltage of the inverter circuit unit 4 is the base frequency voltage. In the formula (4), P _I is the inverter output power, I is the output current is a result of detection by the current detection unit 11.

The acceleration / deceleration interruption determination unit 14 determines that acceleration is interrupted when the calculated inverter output power is equal to or greater than the calculated solar output power. Further, the acceleration / deceleration interruption determination unit 14 determines that acceleration is restarted when the calculated inverter output power is less than the calculated solar output power. The acceleration / deceleration interruption determination unit 14 outputs 1-bit information indicating the determination result of interruption and restart for acceleration. The signal when it is determined that the acceleration is interrupted is "0", and the signal when it is determined that the acceleration is resumed is "1". The signal output by the acceleration / deceleration interruption determination unit 14 is not limited to "0" and "1" as long as it is a signal capable of distinguishing the determination result of interruption and restart for acceleration.

The output frequency calculation unit 15 calculates the command value of the output frequency based on the determination result by the acceleration / deceleration interruption determination unit 14 and the calculation result of the frequency limit value by the frequency limit value calculation unit 13. The output frequency calculation unit 15 outputs a pulse signal based on the command value calculated by the output frequency calculation unit 15 or the frequency limit value calculated by the frequency limit value calculation unit 13 to the inverter circuit unit 4.

Next, the specific operation of the control unit 20 will be described. FIG. 6 is a flowchart showing a procedure of operation by the control unit 20 included in the drive device 5 shown in FIG. In step S1, the abnormal voltage drop determination unit 12 monitors the abnormal voltage drop of the DC voltage. The abnormal voltage drop determination unit 12 determines that there is an abnormal voltage drop when the decrease in the DC voltage value within the set time is a decrease equal to or greater than the threshold value. The abnormal voltage drop determination unit 12 determines that the DC voltage is normal if the value of the DC voltage does not decrease by the threshold value or more within the set time.

In step S2, the acceleration / deceleration interruption determination unit 14 calculates the inverter output power and the solar output power. In step S3, the frequency limit value calculation unit 13 calculates the frequency limit value based on the value of the DC voltage which is the detection result by the voltage detection unit 10.

In step S4, the frequency limit value calculation unit 13 determines whether or not there is an abnormal voltage drop based on the output from the abnormal voltage drop determination unit 12 to the frequency limit value calculation unit 13. When there is an abnormal voltage drop (step S4, Yes), the control unit 20 proceeds to step S5. On the other hand, if there is no abnormal voltage drop (steps S4 and No), the control unit 20 proceeds to step S6.

In step S5, the frequency limit value calculation unit 13 subtracts and corrects the frequency limit value calculated in step S3. In step S6, the output frequency calculation unit 15 determines whether or not the inverter output power is less than the solar output power based on the output from the acceleration / deceleration interruption determination unit 14 to the output frequency calculation unit 15. When the inverter output power is less than the solar output power (steps S6 and Yes), the control unit 20 proceeds to step S8. On the other hand, when the inverter output power is equal to or higher than the solar output power (steps S6 and No), the control unit 20 proceeds to step S7.

In step S7, the output frequency calculation unit 15 outputs a pulse signal based on the command value related to the previous frequency command to the inverter circuit unit 4. In step S8, the output frequency calculation unit 15 determines whether or not the frequency limit value calculated in step S3 or step S5 is less than the command value of the output frequency calculated this time. When the frequency limit value is less than the command value (step S8, Yes), the control unit 20 proceeds to step S10. On the other hand, when the frequency limit value is equal to or greater than the command value (steps S8 and No), the control unit 20 proceeds to step S9.

In step S9, the output frequency calculation unit 15 outputs a pulse signal based on the command value of the output frequency calculated this time to the inverter circuit unit 4. In step S10, the output frequency calculation unit 15 outputs a pulse signal based on the frequency limit value calculated in step S3 or step S5 to the inverter circuit unit 4. As a result, the control unit 20 ends the operation according to the procedure shown in FIG.

The function of the control unit 20 of the drive device 5 is realized by using a processing circuit. The processing circuit is dedicated hardware mounted on the drive device 5. The processing circuit may be a processor that executes a program stored in the memory.

FIG. 7 is a diagram showing a hardware configuration when the function of the control unit 20 included in the drive device 5 shown in FIG. 2 is realized by using dedicated hardware. The processing circuit 41, which is dedicated hardware, is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or these. It is a combination.

FIG. 8 is a diagram showing a hardware configuration when the function of the control unit 20 included in the drive device 5 shown in FIG. 2 is realized by using the processor 42. The processor 42 and the memory 43 are connected to each other so as to be able to communicate with each other. The processor 42 executes a program stored in the memory 43.

The processor 42 is a CPU (Central Processing Unit), a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). The function of the control unit 20 is realized by the processor 42 and software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 43. The memory 43 is non-volatile or volatile such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EEPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory). Built-in memory such as semiconductor memory.

A part of the function of the control unit 20 may be realized by the dedicated hardware, and the other part of the function of the control unit 20 may be realized by software or firmware. As described above, the function of the control unit 20 can be realized by hardware, software, firmware, or a combination thereof.

According to the first embodiment, the photovoltaic power generation drive system 1 calculates the output frequency limit value based on the V / F characteristics and the value of the DC voltage output by the solar panel 2, and the inverter output power is equal to or higher than the solar output power. When the limit value is less than the command value, a pulse signal having a frequency based on the limit value is output to the inverter circuit unit 4. The photovoltaic power generation drive system 1 makes it possible to adjust the inverter output power to be less than the solar output power by limiting the output frequency by a limit value based on the V / F characteristics, and it is possible to reduce the malfunction of the motor 6. The photovoltaic power generation drive system 1 does not need to be adjusted to detect the output voltage of the solar panel 2 by repeatedly changing the rotation speed of the motor 6, so that the time required for the adjustment for controlling the solar output power is not required. Can be shortened. Since the photovoltaic power generation drive system 1 does not need to repeatedly change the rotation speed of the motor 6 at a preset timing, the motor 6 can be stably driven when there is no change in the solar output power. As a result, the photovoltaic power generation drive system 1 has the effect of shortening the time required for adjustment for controlling the output power of the solar panel 2 and enabling stable drive of the load.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 Photovoltaic drive system, 2 Solar panel, 3 Capacitor, 4 Inverter circuit, 5 Drive, 6 Motor, 10 Voltage detector, 11 Current detector, 12 Abnormal voltage drop judgment unit, 13 Frequency limit value calculation unit, 14 Acceleration / deceleration interruption judgment unit, 15 Output frequency calculation unit, 20 Control unit, 41 Processing circuit, 42 Processor, 43 Memory.

Claims (7)

It is a photovoltaic power generation drive system that drives the load using the power output from the solar panel.
An inverter circuit unit that converts the DC voltage output by the solar panel into an AC voltage according to a pulse signal and outputs the AC voltage.
A frequency limit value calculation unit that calculates the limit value of the output frequency, which is the frequency of the AC voltage, based on the preset frequency-voltage characteristics of the AC voltage and the value of the DC voltage output by the solar panel.
An output frequency calculation unit that calculates a command value of the output frequency and outputs a pulse signal based on the command value or the limit value to the inverter circuit unit.
A photovoltaic power generation drive system characterized by being equipped with. When the output power of the inverter circuit unit is equal to or higher than the output power of the solar panel and the limit value is less than the command value, the output frequency calculation unit outputs a pulse signal based on the limit value. The photovoltaic power generation drive system according to claim 1, wherein the solar power generation drive system is characterized. When the output power of the inverter circuit unit is equal to or greater than the output power of the solar panel and the limit value is equal to or greater than the command value, the output frequency calculation unit outputs a pulse signal based on the command value. The photovoltaic power generation drive system according to claim 1 or 2, wherein the solar power generation drive system is characterized. It is provided with an abnormal voltage drop determination unit that determines whether or not the DC voltage drop is an abnormal voltage drop based on the change in the DC voltage value output by the solar panel.
The sun according to any one of claims 1 to 3, wherein the frequency limit value calculation unit performs subtraction correction of the calculated limit value when it is determined that the voltage drop is abnormal. Photovoltaic drive system. The DC voltage V _D, said base frequency of the inverter circuit portion f0, said base frequency voltage of the inverter circuit portion V _f0, output start pressure V _S of the inverter circuit _unit, and the output start frequency of the inverter circuit unit The present invention according to any one of claims 1 to 4, wherein the frequency limit value calculation unit calculates the limit value f _L1 based on the following equation (1), where f _S. Solar power drive system.

The DC voltage V _D, said base frequency of the inverter circuit portion f0, said base frequency voltage of the inverter circuit portion V _f0, output start pressure V _S of the inverter circuit _unit, and the output start frequency of the inverter circuit unit The present invention according to any one of claims 1 to 4, wherein the frequency limit value calculation unit calculates the limit value f _L2 based on the following equation (2), where f _S. Solar power drive system.

A solar power generation drive system that has an inverter circuit unit that converts the DC voltage output by the solar panel into an AC voltage according to a pulse signal and outputs the AC voltage, and drives the load using the power output by the solar panel. It is a control method of
A process of calculating an output frequency limit value, which is the frequency of the AC voltage, based on a preset frequency of AC voltage-voltage characteristics and a value of the DC voltage output by the solar panel.
A process of calculating a command value of an output frequency and outputting a pulse signal based on the command value or the limit value to the inverter circuit unit.
A method of controlling a photovoltaic power generation drive system, which comprises.

Images