JP5497941B2 - Inverter for distributed power supply and control method for inverter for distributed power supply - Google Patents

Description

  The present invention relates to an inverter for a distributed power source including a single-phase voltage type AC / DC converter applicable to a grid interconnection device or an uninterruptible power supply device serving as a power source for a power system, and a control method thereof.

  In the synchronous generator which is the main power source of the current power system, each output deviation can be automatically corrected because each generator has a synchronizing power. For this reason, it can drive | operate autonomously, without performing cross current suppression control. Further, in an inverter (AC / DC converter) that performs power conversion using a semiconductor, a technique of autonomous parallel operation (APRun) is proposed for a three-phase machine (see, for example, Patent Document 1). The three-phase voltage type AC / DC converter of Patent Document 1 UM-converts the three-phase output voltage on the dq rotation coordinates, and each axis component is independent so that the amplitude and frequency of the power system approach the command value by the upper command vector. I try to control it. In addition, by synchronizing the generated value generated from the component related to the frequency difference of the three-phase output voltage with the rotation angle of the conversion matrix in the UM conversion circuit, the rotation angle of the three-phase output voltage is made to follow the frequency of the power system. Can do. In the present specification, the voltage used for alternating current such as “output voltage”, “voltage corresponding to phase difference”, “internal electromotive voltage” means a function having time as a variable.

JP 2007-236083 A Japanese Patent Application No. 2008-039132

  However, UM conversion as described in Patent Document 1 cannot be performed in single-phase alternating current, and autonomous parallel operation is difficult for a single-phase inverter. Further, in a distributed power source that is connected to an electric power system and operated, it is desirable that active power and reactive power can be controlled independently. Therefore, in the present invention, even when a plurality of units are connected in parallel with single-phase alternating current and operated in parallel, autonomous parallel operation in which individual devices autonomously control output deviation is possible, and active power and reactive power. It is an object of the present invention to provide a distributed power source inverter including a single-phase voltage type AC / DC converter capable of independently controlling the power supply and a control method thereof.

  In order to achieve the above object, the present invention generates a single-phase alternating current having a predetermined phase difference from the phase of the single-phase alternating current voltage of the alternating current terminal, and generates the generated single-phase alternating current and the single-phase alternating current voltage of the alternating current terminal. It was decided to use the PWM control of the inverter. That is, the single-phase AC voltage of the AC terminal is the first axis corresponding to the α-axis component when the three-phase AC is converted to M. A single-phase alternating current having a predetermined phase difference is set as a second axis corresponding to a β-axis component when the three-phase alternating current is M-converted. The inverter for distributed power supply of the present invention is a single-phase voltage type AC / DC converter that controls a first axis and a second axis independently, and uses a specific electrical angle generated by a frequency control circuit to generate a single-phase AC voltage. The single-phase voltage type AC / DC converter circuit is controlled so as to obtain desired active power and reactive power by measuring the active power and reactive power of the AC terminal by following the frequency of the power system.

  Specifically, the inverter for distributed power supply according to the present invention has an internal electromotive voltage and an internal equivalent impedance when viewed from the AC terminal, and a DC voltage source according to the pulse width of the gate signal generated based on the PWM command. A single-phase voltage type AC / DC converter circuit that converts the voltage from the AC terminal into a single-phase AC voltage and outputs the same from the AC terminal, and an invalid value for the active power command value and reactive power value for the active power value of the single-phase output power of the AC terminal A power command vector comprising a power command value is input, and based on the power command vector, the active power value of the single-phase output power of the AC terminal, and the reactive power value of the single-phase output power of the AC terminal, A power control signal generated so that the active power value and the reactive power value of the single-phase output power approach the command value by the power command vector is applied to the amplitude of the single-phase AC voltage of the AC terminal. A power control circuit that outputs a high-order command vector composed of a voltage amplitude command value and a frequency command value for a frequency, and a phase-delayed single-phase AC that delays the phase of the single-phase AC voltage at the AC terminal and generates a delayed single-phase AC A phase difference generator that generates a voltage corresponding to a phase difference between a single-phase AC voltage of the AC terminal and the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit based on the delayed single-phase AC The amplitude of the single-phase AC voltage at the AC terminal based on the circuit, the upper command vector from the power control circuit, the voltage corresponding to the phase difference from the phase difference generation circuit, and the single-phase AC voltage at the AC terminal And an upper voltage control circuit that outputs a voltage command signal and a frequency command signal generated so that the frequency approaches a command value by the upper command vector, and a single-phase AC voltage of the AC terminal An electrical angle of the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit based on a reference frequency defining a wave number, a frequency command signal from the higher voltage control circuit, and a voltage corresponding to a phase difference from the phase difference generation circuit A reference voltage that is a reference for the amplitude of the single-phase AC voltage at the AC terminal, and a value obtained by multiplying the reference voltage by a signal based on the electrical angle from the frequency control circuit. A lower voltage control circuit that adds a voltage command signal from the higher voltage control circuit to the internal electromotive voltage and outputs a difference between the internal electromotive voltage and the single-phase AC voltage as the PWM command. A voltage source having a phase voltage type AC / DC converter and outputting a DC voltage generated and rectified by a fuel cell or power storage system that outputs a DC voltage or a power generation method of solar power generation or wind power generation Is the DC voltage source.

  In the present invention, a single-phase voltage type AC / DC converter circuit having an internal equivalent impedance is used so that it can be operated by being connected to a power system even if it operates as a voltage source. The phase difference generation circuit generates a voltage corresponding to the voltage phase difference across the internal equivalent impedance, and the frequency control circuit generates the reference frequency, the frequency command signal from the higher voltage control circuit, and the voltage generated from the voltage corresponding to the phase difference. Synchronize the internal electromotive force to the corner. Thereby, a single phase alternating voltage can be made to follow the frequency of an electric power grid | system.

  In the upper voltage control circuit, the voltage command signal is generated so that the amplitude and frequency of the single-phase output voltage approach the command value by the upper command vector from the power control circuit. Thereby, even if the amplitude and frequency of the power system change, it is possible to detect respective deviations of the amplitude and frequency of the single-phase output voltage of the single-phase voltage type AC / DC converter with respect to the amplitude and frequency. Therefore, it is possible to compensate for the deviation by controlling the amplitude and phase of the single-phase voltage type AC / DC converter so as to match the amplitude and phase of the power system in the lower voltage control circuit.

  As described above, the single-phase voltage type AC / DC converter included in the distributed power source inverter according to the present invention can be operated by connecting to the power system as a voltage source, and autonomously compensates for voltage deviation with respect to the power system. Autonomous parallel operation is possible. As a result, the reliability of the apparatus is increased and distributed arrangement is possible. Further, when a plurality of units are operated in parallel, the units can be operated without any limitation.

  On the other hand, in the power control circuit, based on the input power command vector and the output power vector composed of active power and reactive power measured at the AC terminal, the active power and reactive power of the AC terminal are commanded by the power command vector. An upper command vector is generated and output so as to approach the value. In other words, since the power control circuit converts the power command vector into the upper command vector based on the output power vector, the single-phase voltage type AC / DC converter provided in the distributed power source inverter according to the present invention has the active power of the single-phase output power. The reactive power target value can be given as a command value, and the active power and reactive power of the single-phase output power can be accurately controlled without interference during autonomous parallel operation. In addition, since the target values of the active power and reactive power of single-phase output power are given as command values, the power factor can be controlled to be non-interfering, and if the active power command value of the power command vector is zero, the reactive power command value When the reactive power command value of the power command vector is set to zero, the operation can be performed with the power factor set to 1 without interference with the active power command value.

  Therefore, the present invention is capable of autonomous parallel operation in which individual devices autonomously control output deviation even when a plurality of units are connected in parallel with single-phase AC, and active power and reactive power. It is possible to provide an inverter for a distributed power source including a single-phase voltage type AC / DC converter that can control each of them independently.

  Each configuration of the single-phase voltage type AC / DC converter will be described more specifically. In the single-phase voltage type AC / DC converter, the upper voltage control circuit includes a first multiplier that multiplies the signal based on the electrical angle generated by the frequency control circuit and the upper command vector, and the first multiplier A first subtracter that subtracts the AC voltage of the AC terminal from the signal output from the signal, and a signal from the first subtractor so that the single-phase AC voltage of the AC terminal approaches the command value by the upper command vector. A first upper control amplifier that amplifies and outputs the voltage command signal; a second subtracter that subtracts a voltage corresponding to a phase difference from the phase difference generation circuit from the upper command vector; and a single phase of the AC terminal A second upper control amplifier that amplifies the signal from the second subtractor and outputs it as the frequency command signal so that an AC voltage approaches the command value by the upper command vector, The low-order voltage control circuit multiplies a reference voltage setter for setting and outputting the reference voltage, a signal based on the electrical angle generated by the frequency control circuit, and a reference voltage from the reference voltage setter. A second multiplier, a first adder that adds the voltage command signal from the higher voltage control circuit and a signal output from the second multiplier to output the internal electromotive voltage, and the first adder outputs A third subtracter that subtracts the single-phase AC voltage of the AC terminal from the signal to be transmitted, and the single-phase AC voltage of the AC terminal so as to approach a combined value of the signal based on the reference voltage, the voltage command signal, and the electrical angle. A voltage controller that controls a signal output from the third subtractor and outputs a PWM command, and the frequency control circuit includes the frequency command signal from the higher voltage control circuit and the phase difference generation circuit. Phase difference from A second adder for adding corresponding voltages; a loop filter for adding a low-pass filter element to the frequency component of the signal output from the second adder; and a reference frequency setting unit for setting the reference frequency A third adder that adds the output value of the reference frequency setter to the output value of the loop filter, and a time integrator that time-integrates a signal output from the third adder and outputs the signal as the electrical angle. It is desirable to have

  In the present invention, the subtracter of the upper voltage control circuit subtracts the voltage corresponding to the phase difference from the phase difference generation circuit and the upper command vector and outputs the frequency command signal. The frequency control circuit adds the frequency command signal and the voltage corresponding to the phase difference from the phase difference generation circuit, adds a low-pass filter element in the loop filter of the frequency control circuit, and outputs the result. In addition, the signal from the loop filter is added to the reference frequency output from the reference frequency setter, and the electric angle is generated by time integration with the time integrator, and the electric angle of the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit. Synchronize. Thereby, the rotation angle of a single phase alternating voltage can be made to follow the frequency of an electric power grid | system.

  On the other hand, the subtracter of the upper voltage control circuit subtracts the single-phase AC voltage and the upper command vector to output a voltage command signal. As a result, even if the amplitude and frequency of the power system change, the respective error components of the amplitude and frequency of the single-phase output voltage of the single-phase voltage type AC / DC converter for the amplitude and frequency are detected, and the lower voltage control circuit The error can be compensated.

  Specifically, the voltage command signal from the higher voltage control circuit is added to the reference voltage from the reference voltage setter in the lower voltage control circuit. Furthermore, the single-phase AC voltage of the AC terminal is subtracted from the signal obtained by adding the reference voltage and the voltage command signal, and the difference between the amplitude and phase of the power system is converted into the combined value of the reference voltage and the voltage command vector by the voltage controller. It converts so that it may approach, and outputs it as a PWM command. An auxiliary signal described later may be added to the PWM command. Thereby, it is possible to control the amplitude and phase of the single-phase AC voltage of the single-phase voltage type AC / DC converter so as to match the amplitude and phase of the power system.

  As described above, the single-phase voltage type AC / DC converter can be operated by being connected to a power system as a voltage source, and can be operated autonomously in parallel with the power system or another AC power source. As a result, the reliability of the apparatus is increased and distributed arrangement is possible. Further, when a plurality of units are operated in parallel, the units can be operated without any limitation. Therefore, the present invention is capable of autonomous parallel operation in which individual devices autonomously control output deviation even when a plurality of units are connected in parallel with single-phase AC, and active power and reactive power. It is possible to provide an inverter for a distributed power source including a single-phase voltage type AC / DC converter that can control each of them independently.

  Next, a single-phase voltage type AC / DC converter that adds an auxiliary signal to a PWM signal will be described. The single-phase voltage type AC / DC converter further includes an output current detection circuit for detecting a single-phase AC current at the AC terminal, and the lower-level voltage control circuit is a single-phase AC filter included in the single-phase voltage type AC / DC converter circuit. A filter current compensator that outputs a current compensation value defined to compensate for a current loss in the circuit, and a current deviation of a single-phase AC current from the single-phase voltage type AC / DC converter circuit. A PWM current deviation compensator that outputs a current deviation compensation value and a single-phase AC current value detected by the output current detection circuit are input, and a predetermined feedforward gain is applied so as to compensate the current to the load of the AC terminal. A feedforward amplifier that amplifies and outputs, a current compensation value of the filter current compensator, a current deviation compensation value from the PWM current deviation compensator, and the filter A fourth adder for adding an output value from the feedforward amplifier to the PWM command value from the voltage controller, it is desirable to have.

  In the present invention, the current deviation in the single-phase voltage type AC / DC converter circuit when the PWM command is set to zero command is set in advance in the PWM current deviation compensator, and the current deviation is added to the PWM command from the voltage controller. Minutes can be compensated. In addition, the current loss in the single-phase AC filter circuit of the single-phase voltage type AC / DC converter circuit is set in advance in the filter current compensator and added to the PWM command from the voltage controller to compensate for the current loss. it can. Furthermore, a stable output voltage can be generated even if the output current changes by amplifying the value of the single-phase AC current at the AC terminal with a feedforward amplifier and adding it to the PWM command from the voltage controller. That is, in the present invention, signals from the PWM current deviation compensator, the filter current compensator and the feedforward amplifier are added as auxiliary signals to the PWM command from the voltage controller.

  In the single-phase voltage type AC / DC converter provided in the distributed power source inverter according to the present invention, the single-phase voltage type AC / DC converter circuit has the internal electromotive voltage and the internal equivalent impedance when viewed from the AC terminal, and the gate signal. A single-phase voltage type AC / DC converter that converts the voltage from the DC voltage source into a single-phase AC voltage according to the pulse width of the output, and detects the single-phase AC current of the single-phase voltage type AC / DC converter, and A current detection circuit that outputs a signal generated according to the magnitude of a single-phase alternating current, and the gate signal is generated and output so that the difference between the PWM command and the output from the current detection circuit approaches zero. A gate signal generator and a single-phase AC filter circuit that removes a high-frequency component caused by the gate signal in the single-phase voltage type AC / DC converter from the single-phase AC voltage of the single-phase voltage type AC / DC converter and outputs the signal It is desirable to have a.

  In the present invention, since the single-phase AC filter circuit is provided, a high-frequency component caused by the gate signal in the single-phase voltage type AC / DC converter can be removed from the output from the single-phase voltage type AC / DC converter. In addition, the current detection circuit detects the current from the single-phase voltage type AC / DC converter, and the gate signal generator generates a gate signal so that the difference between the PWM command and the output from the current detection circuit approaches zero. Control can be performed so that the current error falls within an allowable range.

  Further, in the single-phase voltage type AC / DC converter provided in the distributed power source inverter according to the present invention, the single-phase voltage type AC / DC converter circuit has the internal electromotive voltage and the internal equivalent impedance when viewed from the AC terminal. A single-phase voltage type AC / DC converter that converts the voltage from the DC voltage source into a single-phase AC voltage according to the pulse width of the gate signal and outputs the single-phase AC voltage of the single-phase voltage type AC / DC converter A voltage detection circuit that outputs a signal generated according to the magnitude of the single-phase AC voltage, and the gate signal is generated so that a difference between the PWM command and the output from the voltage detection circuit approaches zero. A single-phase AC filter that outputs a high-frequency component due to the gate signal in the single-phase voltage type AC / DC converter from the single-phase AC voltage of the single-phase voltage type AC / DC converter, and outputs the gate signal generator It is desirable to have a circuit.

  In the present invention, since the single-phase AC filter circuit is provided, a high-frequency component caused by the gate signal in the single-phase voltage type AC / DC converter can be removed from the output from the single-phase voltage type AC / DC converter. In addition, the voltage detection circuit detects the voltage from the single-phase voltage type AC / DC converter, and the gate signal generator generates a gate signal so that the difference between the PWM command and the output from the voltage detection circuit approaches zero. The output voltage can be made to follow the PWM command.

  The power control circuit of the single-phase voltage type AC / DC converter generates the power control signal by integrating a difference between the power command vector and a single-phase output power measurement value of the AC terminal and low-pass filtering. Is desirable. This is because there are few transient fluctuations and the steady-state error can be made zero.

  The single-phase voltage type AC / DC converter may further include a limiter that determines an upper limit and a lower limit of the upper command vector, and the upper command vector is preferably input to the upper voltage control circuit via the limiter.

  An excessively high order command vector can be prevented from being input, and an abnormal single-phase AC output current can be prevented from being output to the power system.

  In the single-phase voltage type AC / DC converter, either the active power command value or the reactive power command value of the power command vector can be set to zero. In the single-phase voltage type AC / DC converter, since the target values of the active power and reactive power of the single-phase output power are given as command values, if the active power command value of the power command vector is set to zero, the reactive power command value and The operation can be performed with the power factor set to zero for non-interference. On the other hand, when the reactive power command value of the power command vector is set to zero, the operation can be performed with the power factor set to 1 for non-interference with the active power command value.

  In the present invention, even when a plurality of units are connected in parallel with single-phase alternating current and operated in parallel, autonomous parallel operation in which individual devices autonomously control output deviation is possible, and active power and reactive power are It is possible to provide a distributed power source inverter including a single-phase voltage type AC / DC converter that can be independently controlled.

It is a schematic block diagram of the single phase voltage type | mold AC / DC converter with which the inverter for distributed power sources which concerns on this invention is provided. It is a schematic block diagram of the single phase voltage type | mold AC / DC converter with which the inverter for distributed power sources which concerns on this invention is provided. It is a schematic block diagram of the single phase voltage type | mold AC / DC converter with which the inverter for distributed power sources which concerns on this invention is provided. It is a schematic block diagram of the single phase voltage type | mold AC / DC conversion circuit with which a single phase voltage type | mold AC / DC converter is provided. It is a schematic block diagram of the single phase voltage type | mold AC / DC conversion circuit with which a single phase voltage type | mold AC / DC converter is provided. It is a schematic block diagram of the alternating current power measuring device with which a single phase voltage type | mold AC / DC converter is provided. It is a schematic block diagram of the alternating current power measuring device with which a single phase voltage type | mold AC / DC converter is provided. It is the result of having simulated the operation | movement of PQ control in case the single phase voltage type | mold AC / DC converter (100V, 50Hz, 1kVA) is connected with the power system of 100V and 50Hz. It is the figure which showed the connection relationship of the control block in the single phase voltage type | mold AC / DC converter with which the inverter for distributed power sources which concerns on this invention is provided. It is a schematic block diagram of the phase difference generation circuit with which a single phase voltage type | mold AC / DC converter is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to embodiment shown below. In the present specification and drawings, the same reference numerals denote the same components.

  FIG. 9 is a diagram illustrating a connection relationship of control blocks in the single-phase voltage type AC / DC converter included in the distributed power source inverter. As in the case of the three-phase voltage type AC / DC converter, a higher order command vector B1, an uppermost control block B2, an ac-AVR block B3, an ETM-PWM block B4, and a main switch B5 are included. For the ac-AVR block B3, by applying the single-phase ac-AVR mainly composed of the internal equivalent impedance described in Patent Document 2, there is a risk of demagnetization in the transformer connected to the output circuit of the inverter. Disappear. Furthermore, since the internal equivalent impedance can be a parallel circuit of a resistance component and an inductance component, the degree of freedom in design increases.

  1 and 2 are schematic configuration diagrams of a single-phase voltage type AC / DC converter included in the distributed power source inverter according to the present embodiment, and each block shown in FIG. 9 will be described in more detail.

  The single-phase voltage type AC / DC converter 11 shown in FIG. 1 has an internal electromotive voltage and an internal equivalent impedance when viewed from the AC terminal 22, and a DC voltage source according to the pulse width of the gate signal generated based on the PWM command. A single-phase voltage type AC / DC conversion circuit 40 that receives a voltage from (not shown) at the DC terminal 21, converts it to a single-phase AC voltage and outputs it from the AC terminal 22, and an active power value of the single-phase AC voltage at the AC terminal 22. A power command vector 130 composed of a reactive power command value and a reactive power value for the reactive power value is input, and the power command vector 130, the active power value of the single-phase output power of the AC terminal 22 and the single-phase output power of the AC terminal 22 The power control signal generated based on the reactive power value of the AC terminal 22 so that the active power value and reactive power value of the single-phase output power of the AC terminal 22 approach the command value by the power command vector 130 The power control circuit 150 that outputs a voltage command value for the amplitude of the single-phase AC voltage at the AC terminal 22 and the frequency command value for the frequency as the upper command vector 120, and the phase with respect to the single-phase AC voltage at the AC terminal 22 A phase-delayed single-phase alternating current generator for generating a delayed single-phase alternating current, and based on the delayed single-phase alternating current, the single-phase alternating current voltage at the alternating-current terminal 22 and the internal generation of the single-phase voltage type AC / DC converter circuit 40 A phase difference generation circuit 30 for generating a voltage corresponding to the phase difference from the voltage, a higher order command vector 120 from the power control circuit 150, a voltage corresponding to the phase difference from the phase difference generation circuit 30, and a single phase of the AC terminal 22 Based on the AC output, the voltage command signal and the frequency generated so that the amplitude and frequency of the single-phase AC voltage of the AC terminal 22 approach the command value by the upper command vector 120. Corresponds to the upper voltage control circuit 70 that outputs the command signal, the reference frequency that defines the frequency of the single-phase AC voltage at the AC terminal 22, the frequency command signal from the upper voltage control circuit 70, and the phase difference from the phase difference generation circuit 30. A frequency control circuit 50 that generates an electrical angle of the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit 40 based on the voltage to be applied, and a reference voltage that is a reference for the amplitude of the single-phase AC voltage at the AC terminal 22 is set. The voltage command signal from the higher voltage control circuit 70 is added to the value obtained by multiplying the signal based on the electrical angle from the frequency control circuit 50 and the reference voltage to obtain the internal electromotive voltage. A lower voltage control circuit 60 that outputs a difference from the phase AC voltage as the PWM command.

  The upper command vector 120 corresponds to the upper command vector B1 in FIG. The upper voltage control circuit 70 corresponds to the uppermost control block B2 in FIG. The lower voltage control circuit 60 and the frequency control circuit 50 correspond to the ac-AVR block B3 in FIG. The gate signal generator 41 corresponds to the ETM-PWM block B4 in FIG. The single-phase voltage type AC / DC converter included in the single-phase voltage type AC / DC converter circuit 40 corresponds to the main switch B5 of FIG.

  The single-phase voltage type AC / DC converter circuit 40 converts a voltage from a DC voltage source (not shown) into a single-phase AC voltage according to the pulse width of the gate signal generated by the gate signal generator 41 based on the PWM command. A DC voltage source is a voltage source that outputs a DC voltage by itself, such as a battery, a voltage source that generates and rectifies by a power generation method such as wind power generation, or outputs a DC voltage, or controls a DC capacitor voltage to generate a DC voltage. A voltage source to be output can be exemplified. In this case, a blocking inductor may be further provided between the connection point of the output voltage detection circuit 31 and the AC terminal 22, and each single-phase AC voltage may be output from the AC terminal 22 via the blocking inductor. The outflow of the PWM component to the AC terminal 22 in the single-phase voltage type AC / DC converting circuit 40 can be prevented.

  4 and 5 show schematic configuration diagrams of the single-phase voltage type AC / DC converter circuit.

  A single-phase voltage type AC / DC converting circuit 40-1 shown in FIG. 4 has an internal electromotive voltage and an internal equivalent impedance when viewed from the AC terminal 22, and supplies a voltage from a DC voltage source according to the pulse width of the gate signal. The single-phase voltage type AC / DC converting unit 42 that receives the signal and converts it into a single-phase AC voltage and outputs the single-phase AC type output current, and detects the single-phase AC output current of the single-phase voltage type AC / DC converting unit 42 according to the magnitude of the single-phase AC output current. A current detection circuit 43 that outputs the generated signal, a gate signal generator 41 that generates and outputs a gate signal so that the difference between the PWM command and the output from the current detection circuit 43 approaches zero, and a single-phase voltage A single-phase AC filter circuit 45 that removes a high-frequency component caused by the gate signal in the single-phase voltage type AC / DC converter 42 from the single-phase AC voltage of the type AC / DC converter 42 and outputs the result.

  Further, the single-phase voltage type AC / DC converting circuit 40-2 shown in FIG. 5 detects the single-phase AC voltage of the single-phase voltage type AC / DC converting unit 42 instead of the current detection circuit 43 of FIG. A voltage detection circuit 44 that outputs a signal generated according to the magnitude is provided. In this case, the gate signal generator 41 generates and outputs a gate signal so that the difference between the PWM command and the output from the voltage detection circuit 44 approaches zero.

  The internal equivalent impedance of the single-phase voltage type AC / DC converter 42 shown in FIGS. 4 and 5 can be given by the control variable in the single-phase voltage type AC / DC converter 11 of FIG. The outputs of the single-phase voltage type AC / DC converting circuits 40-1 and 40-2 may be connected to a resistor, a reactor, a single-phase transformer, or a combination thereof. For example, a resistor or a reactor may be connected in series to the single-phase output of each of the single-phase voltage type AC / DC converter circuits 40-1 and 40-2. You may connect in series. Moreover, you may connect a single phase transformer to the single phase output of the single phase voltage type | mold AC / DC conversion circuit 40-1, 40-2. Moreover, when a reactor is connected to the single-phase output of each of the single-phase voltage type AC / DC conversion circuits 40-1 and 40-2, a single-phase transformer may be connected to the subsequent stage of the reactor. Furthermore, when a resistor is connected to the single-phase output of each of the single-phase voltage type AC / DC converter circuits 40-1 and 40-2, and a reactor is connected in series to the subsequent stage of the resistor, a single-phase transformer is connected to the subsequent stage of the reactor. A vessel may be connected. As described above, since the single-phase voltage type AC / DC converter circuit 40 has an internal equivalent impedance, the single-phase voltage type AC / DC converter 11 of FIG. 1 can be operated as a voltage source connected to the power system. .

  The single-phase voltage type AC / DC converter circuit 11 shown in FIG. 1 has the configuration shown in FIG. 4 or 5, so that the single-phase voltage type AC / DC converter 11 includes a single-phase AC filter circuit 45 (FIGS. 4 and 5). Therefore, it is possible to remove a high-frequency component caused by the gate signal in the single-phase voltage type AC / DC converter 42 from the output from the single-phase voltage type AC / DC converter 42. The current detection circuit 43 or the voltage detection circuit 44 detects the current or voltage from the single-phase voltage type AC / DC converter 42, and the gate signal generator 41 outputs the PWM command and the output from the current detection circuit 43 or the voltage detection circuit 44. By generating a gate signal so that the difference between and the current value approaches zero, the current error can be controlled to be within an allowable range, or the output voltage can be made to follow the PWM command.

  The output voltage detection circuit 31 in FIG. 1 detects the single-phase AC voltage at the AC terminal 22 and outputs it to the phase difference generation circuit 30, the lower voltage control circuit 60, and the upper voltage control circuit 70, respectively. Further, a low-pass filter may be provided in front of the output voltage detection circuit 31, and the single-phase AC voltage to the output voltage detection circuit 31 may be detected via the low-pass filter. It is possible to stabilize the control of the single-phase voltage type AC / DC converter 11 by removing the PWM component from the single-phase AC voltage. Further, a low-pass filter may be provided after the output voltage detection circuit 31, and the output voltage from the output voltage detection circuit 31 may be output via the low-pass filter. The PWM component can be removed from the output voltage from the output voltage detection circuit 31 to stabilize the control of the single-phase voltage type AC / DC converter 11.

  The output current detection circuit 34 of FIG. 1 detects the single-phase AC output current of the AC terminal 22 via the current transformer 38 and outputs it to the AC power measuring device 140.

1 generates a voltage corresponding to the phase difference between the single-phase AC voltage V _FIL (t) at the AC terminal 22 and the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit 40. FIG. 10 is an example of a schematic configuration diagram of the phase difference generation circuit 30. The phase difference generation circuit 30 is input from the terminal 33-1 and a phase-delayed single-phase AC generator 35 that generates a delayed single-phase AC delayed from a single-phase AC voltage input from the terminal 33-1 by a predetermined phase. A phase difference voltage generator 36 for generating a voltage corresponding to a phase difference from a single-phase AC voltage, a delayed single-phase AC voltage from the phase-lag single-phase AC generator 35, and a value input from the terminal 33-3; A terminal 33-2 for outputting a voltage corresponding to the phase difference is provided. In FIG. 10, the phase-delayed single-phase AC generator 35 delays the phase of the delayed single-phase AC by approximately 90 °. However, the phase to be delayed may be any angle as long as it is not 0 ° and 180 °.

ここで、ω_ｓ：角周波数［ｒａｄ／ｓ］、θ_ｓ：位相角［ｒａｄ］、Ｅ_ｓ：実効値［Ｖ］である。なお、位相角の基準を内部起電圧におく。 A single-phase AC voltage V _FIL (t) detected by the output voltage detection circuit 31 is input to the terminal 33-1. An electrical angle 57 generated by a frequency control circuit 50 described later is input to the terminal 33-3. The single-phase AC voltage V _FIL (t) at the AC terminal 22 can be expressed by Equation 1.

Here, ω _s : angular frequency [rad / s], θ _s : phase angle [rad], and E _s : effective value [V]. The reference for the phase angle is set to the internal electromotive voltage.

When the angular frequency ω _s of the single-phase AC voltage at the AC terminal 22 and the reference angular frequency ω _{co of the} single-phase voltage type AC / DC converter circuit 40 are equal, the single-phase AC voltage V _FIL (t) and the phase-lag single-phase AC voltage The phase difference from V ″ _FIL (t) is 90 °, and the phase-lag single-phase AC voltage V ″ _FIL (t) generated by the phase-lag single-phase AC generator 35 can be expressed by Equation 2.

θ_ｉの角速度がω_ｓに等しくなれば、数式３は定数となる。θ_ｓは内部等価インピーダンス両端電圧の位相差であるので一般的に小さい。そこで、Ｖ_ｑ（ｔ）は数式４のように近似できる。

The phase difference voltage generator 36 generates a voltage V _q (corresponding to the phase difference from the single-phase AC voltage V _FIL (t), the phase-lag single-phase AC voltage V ″ _FIL (t) and the generated value generated by the frequency control circuit 50. The voltage V _q (t) corresponding to the phase difference is expressed by Equation 3.

If the angular velocity of θ _i is equal to ω _s , Equation 3 becomes a constant. Since θ _s is the phase difference of the voltage across the internal equivalent impedance, it is generally small. Therefore, V _q (t) can be approximated as Equation 4.

The phase difference generation circuit 30 outputs a voltage corresponding to the generated phase difference to the frequency control circuit 50 and the upper voltage control circuit 70, respectively. Although only the case where ω _s is equal to ω _co is shown here, a similar approximate solution can be obtained even when ω _s is not equal, and there is no practical problem.

  The frequency control circuit 50 is based on a reference frequency that defines the frequency of the single-phase AC voltage at the AC terminal 22, a frequency command signal from the upper voltage control circuit 70, and an output signal from the phase difference generation circuit 30. The electrical angle of the internal electromotive voltage of the conversion circuit 40 is determined. Specifically, as shown in FIG. 2, the second adder 56 adds the frequency command signal from the higher voltage control circuit 70 and the voltage corresponding to the phase difference from the phase difference generation circuit 30. The loop filter 53 filters the low frequency component, which is a component related to the frequency difference of the single-phase AC voltage, from the frequency component of the signal output from the second adder 56. The low-pass filtering element added in the loop filter 53 is a delay element such as a first-order delay element, for example. Thereby, the feedback loop can be stabilized.

The third adder 58 adds the reference frequency output from the reference frequency setting unit 51 and the output value of the loop filter 53. The time integrator 55 integrates the output from the third adder 58 with time. The time integrator 55 time-integrates the output from the third adder 58 to obtain the electrical angle 57 that becomes the natural angle θ _i .

  The electrical angle 57 becomes the electrical angle of the internal electromotive voltage of the single-phase voltage type AC / DC converting circuit 40 by the second multiplier 65 of the lower voltage control circuit 60. Thereby, the said rotation angle can be made to follow the frequency of an electric power grid | system.

  Here, the phase difference generation circuit 30 outputs a voltage corresponding to the phase difference between the single-phase AC voltage of the AC terminal 22 and the internal electromotive voltage of the single-phase voltage type AC / DC conversion circuit 40 as described above. For this reason, the signal processing in the phase difference generation circuit 30 is considered to correspond to phase comparison processing for comparing the phases of the single-phase AC voltage and the electrical angle 57 from the frequency control circuit 50. In addition, the signal processing for adding and integrating the reference frequency from the reference frequency setting unit 51 and the output value from the loop filter 53 is a VCO (VCO) that varies the value of the electrical angle 57 in accordance with the output voltage from the loop filter 53. (Voltage Controlled Oscillator) signal processing. Therefore, it is considered that the phase difference generation circuit 30 and the frequency control circuit 50 operate as a PLL whose electric angle 57 is synchronized with the frequency of the single-phase AC voltage at the AC terminal 22 as a whole.

  An upper command vector 120 from a power control circuit 150 described later is input to the upper voltage control circuit 70 in FIG. 1, and a voltage corresponding to the electrical angle 57 from the frequency control circuit 50 and the phase difference from the phase difference generation circuit 30. In addition, the single-phase AC voltage of the AC terminal 22 is input. Based on these inputs, the upper voltage control circuit 70 outputs a voltage command signal and a frequency command signal generated so that the amplitude and frequency of the single-phase AC voltage at the AC terminal 22 approach the command value by the upper command vector 120. . The upper voltage control circuit 70 may not be directly input with the upper command vector 120 but may be input through a limiter 121 that determines an upper limit and a lower limit of the upper command vector 120. Specifically, as shown in FIG. 2, the first multiplier 73 multiplies the value obtained by multiplying the sine value of the electrical angle 57 from the frequency control circuit 50 by √2 and the voltage amplitude command value of the upper command vector 120. To do. The first subtractor 71 a subtracts the AC output voltage of the AC terminal 22 from the signal from the first multiplier 73. The first upper control amplifier 72a amplifies the signal from the first subtractor 71a and outputs it as a voltage command signal so that the single-phase AC voltage at the AC terminal 22 approaches the command value by the upper command vector 120. The second subtractor 71b subtracts a voltage corresponding to the phase difference from the phase difference generation circuit 30 from a value obtained by multiplying the frequency command value of the higher order command vector 120 by √2. The second upper control amplifier 72b amplifies the signal from the second subtractor 71b and outputs it as a frequency command signal so that the frequency of the single-phase AC voltage at the AC terminal 22 approaches the command value by the upper command vector 120.

  Thereby, even if the amplitude and frequency of an electric power system change, each error of the amplitude and frequency of the single phase AC voltage of the single phase voltage type | mold AC / DC converter 11 with respect to the said amplitude and frequency can be detected. Here, in the first high-order control amplifier 72a and the second high-order control amplifier 72b, a low-pass filter element may be added to the outputs from the first subtractor 71a and the second subtractor 71b. Thereby, the feedback loop can be stabilized. Further, a limiter may be further provided after the first upper control amplifier 72a and the second upper control amplifier 72b, and outputs from the first upper control amplifier 72a and the second upper control amplifier 72b may be output via the limiter. . Over-output can be prevented and control can be stabilized.

  1 is based on the single-phase AC voltage at the AC terminal 22, the electrical angle command signal including the electrical angle 57 of the frequency control circuit 50, and the voltage command signal from the upper voltage control circuit 70. As a PWM command, a signal generated so that the amplitude, frequency, and phase of the phase AC voltage approach a reference voltage that defines the amplitude of the single-phase AC voltage at the AC terminal 22, the combined value of the voltage command signal and the electrical angle command signal. Output. The reference voltage is set in advance by the reference voltage setting unit 61. This reference voltage is a reference for the amplitude of the single-phase AC voltage at the AC terminal 22.

  Specifically, as shown in FIG. 2, a reference voltage setting unit 61 sets and outputs a reference voltage. The second multiplier 65 multiplies the value obtained by multiplying the sine value of the electrical angle 57 from the frequency control circuit 50 by √2 and the reference voltage from the reference voltage setting unit 61. The first adder 62 adds and outputs the voltage command signal from the higher voltage control circuit 70 and the signal output from the second multiplier 65 (corresponding to an internal electromotive voltage). The third subtracter 63 subtracts the signal from the output voltage detection circuit 31 from the signal output from the first adder 62. A voltage controller 64 controls a signal output by the third subtractor 63 so that a single-phase AC voltage at the AC terminal 22 approaches the combined value of the reference voltage, the voltage command signal, and the electrical angle command signal; Output as PWM command.

  This compensates for the deviation detected by the high-order voltage control circuit 70 and also makes the single-phase voltage so that the amplitude and phase of the single-phase AC voltage of the single-phase voltage type AC / DC converter 11 coincide with the amplitude and phase of the power system. The amplitude and phase of the mold AC / DC converter 11 can be controlled. For example, an amplifier can be applied to the voltage controller 64. Here, a low-pass filter may be further provided between the third subtractor 63 and the voltage controller 64, and an output from the third subtractor 63 may be output via the low-pass filter. Control by the voltage controller 64 can be stabilized. Further, a voltage limiter is further provided between the third subtracter 63 and the voltage controller 64 (between the low-pass filter and the voltage controller 64 when a low-pass filter is provided at this position), and the third subtractor 63 is provided. It is good also as outputting the output from via a voltage limiter. Transient fluctuations in the output voltage when the single-phase voltage type AC / DC converter 11 is started up can be suppressed.

  1 receives the value of the single-phase AC voltage of the AC terminal 22 detected by the output voltage detection circuit 31 and the value of the single-phase AC output current of the AC terminal 22 detected by the output current detection circuit 34. Then, the active power value and reactive power value of the single-phase output power at the AC terminal 22 are calculated.

  Specifically, as shown in FIG. 6, the AC power measuring device 140 multiplies the voltage and current at the power measurement points measured by the voltage detection circuit 31 and the current detection circuit 34 by a multiplier 147-1. The product is passed through the low-pass filter 149-1 and the active power value measuring circuit 145 measures the active power value. Further, a function in which the current phase at the power measurement point is shifted by 90 degrees by the current phase delay circuit 143 is generated, and a product obtained by multiplying the function and the voltage at the power measurement point by the multiplier 147-2 is given to the low-pass filter 149-2. Then, the reactive power value measuring circuit 146 measures the reactive power value.

  Further, the AC power measuring device 140 may be configured as shown in FIG. The AC power measuring device 140 generates a reference frequency circuit 141 that generates a reference frequency, and delays the phase of the measurement AC voltage that is an AC voltage at the power measurement point based on the reference frequency from the reference frequency circuit 141 to generate a delayed AC voltage. A voltage phase delay circuit 142 to be generated; a current phase delay circuit 143 that generates a delayed AC current by delaying the phase of the measurement AC current that is an AC current at the power measurement point based on the reference frequency from the reference frequency circuit 141; A power calculation circuit 144. In the power calculation circuit 144, the multiplication value obtained by multiplying the measurement AC voltage and the measurement AC current by the multiplier 147-1 is multiplied by the delay AC voltage from the voltage phase delay circuit 142 and the delay AC current from the current phase delay circuit 143. An addition value obtained by adding the multiplication value multiplied by the adder 148-1 by the adder 148-1 is passed through the low-pass filter 149-1 and measured by the active power value measuring circuit 145 as an effective power value. Further, the multiplier 147-3 multiplies the measured AC voltage and the delayed AC current from the current phase delay circuit 143 by the multiplication value obtained by multiplying the measured AC current and the delayed AC voltage from the voltage phase delay circuit 142 by the multiplier 147-4. The subtracted value obtained by subtracting the multiplied value obtained by the subtractor 148-2 is passed through the low-pass filter 149-2 and measured as the reactive power value by the reactive power value measuring circuit 146. By adding the multiplied value of the delayed AC voltage and the delayed AC current to the multiplied value of the measured AC voltage and the measured AC current, the double frequency component included in the active power value can be reduced. Further, the double frequency component included in the reactive power value can be reduced by subtracting the multiplication value of the measurement AC voltage and the delay AC current from the multiplication value of the measurement AC current and the delay AC voltage. For this reason, the measurement accuracy of the active power value and the reactive power value can be improved, and the active power value and the reactive power value can be accurately controlled.

  The power control circuit 150 of FIG. 1 includes a power command vector 130 composed of an active power command value for the active power value of the single-phase output power of the AC terminal 22 and a reactive power command value for the reactive power value, and an AC power measuring device 140. The calculated active power value and reactive power value of the single-phase output power of the AC terminal 22 are input. The power control circuit 150 generates a power control signal generated so that the active power value and the reactive power value of the single-phase output power of the AC terminal 22 approach the command value by the power command vector 130, as the single-phase output voltage of the AC terminal 22. It is output as a high-order command vector 120 comprising a voltage amplitude command value for amplitude and a frequency command value for frequency. For example, if the active power command value of the power command vector 130 is set to zero, the single-phase voltage type AC / DC converter 11 can be operated with a power factor of zero in non-interference with the reactive power command value. If the reactive power command value of the vector 130 is set to zero, the single-phase voltage type AC / DC converter 11 can operate with a power factor of 1 without interference with the active power command value.

  Specifically, the power control circuit 150 generates a power control signal by integrating the difference between the power command vector 130 and the active power value and reactive power value of the single-phase output power of the AC terminal 22 and low-pass filtering. .

  In FIG. 3, the schematic block diagram of the single phase voltage type | mold AC / DC converter which concerns on another form is shown.

  3 further includes a filter current compensator 66, a PWM current deviation compensator 67, and a feed forward in addition to the output from the voltage controller 64 of the single phase voltage type AC / DC converter 11 shown in FIG. The output from the amplifier 68 is added in the fourth adder 69. In this case, any of the single-phase voltage type AC / DC conversion circuits 40-1 and 40-2 described in FIG. 4 or FIG. Therefore, in FIG. 3, it is assumed that the single-phase voltage type AC / DC converting circuits 40-1 and 40-2 in FIG. 4 or 5 are applied.

  The filter current compensator 66 outputs a current compensation value defined so as to compensate for a current loss in the single-phase AC filter circuit 45 (FIG. 4 or FIG. 5) in the single-phase voltage type AC / DC converter circuit 40. Thereby, in the single-phase voltage type AC / DC converter 11, the current loss in the single-phase AC filter circuit 45 of FIG. 4 or 5 is set in advance in the filter current compensator 66 and added to the output vector from the voltage controller 64. By doing so, the current loss can be compensated. The PWM current deviation compensator 67 outputs a current deviation compensation value defined so as to compensate for the current deviation of the single-phase AC output current from the single-phase voltage type AC / DC converter circuit 40. Thus, in the single-phase voltage type AC / DC converter 11, the current deviation in the single-phase voltage type AC / DC converter circuit 40 when the PWM command is set to zero is set in advance in the PWM current deviation compensator 67, and the voltage controller 64. Can be compensated for by adding to the output vector from. The feedforward amplifier 68 receives the value of the single-phase AC output current detected by the output current detection circuit 34, amplifies it with a predetermined feedforward gain so as to compensate the current for the load at the AC terminal 22, and outputs the amplified signal. . As a result, in the single-phase voltage type AC / DC converter 11, the output current detection circuit 34 detects the single-phase AC output current of the AC terminal 22, and the value passes through the feedforward amplifier 68 and is output from the voltage controller 64. By adding to, a stable output voltage can be generated even if the load current changes.

  The limiter 121 sets an upper limit and a lower limit of the upper command vector 120 and prevents an excessive upper command vector 120 from being input to the upper voltage control circuit 70.

  As described above, the single-phase voltage type AC / DC converter 11 of FIGS. 1 to 3 has an internal equivalent impedance, so that it can be operated as a voltage source connected to the power system, and the frequency control circuit 50 Since the upper voltage control circuit 70 and the lower voltage control circuit 60 are provided, autonomous parallel operation that autonomously compensates for voltage deviation with respect to the power system is possible. As a result, the reliability of the apparatus is increased and distributed arrangement is possible. Further, when a plurality of units are operated in parallel, the units can be operated without any limitation.

(simulation result)
Hereinafter, controlling the active power and the reactive power independently is referred to as PQ control. FIG. 8 shows the result of simulating the operation of PQ control when the single-phase voltage type AC / DC converter 11 (100 V, 50 Hz, 1 kVA) of FIG. 3 is connected to a power system of 100 V, 50 Hz. PQ control was started at time 60 ms, and at time 80 ms, the active power command value of the power command vector was 900 W, and the reactive power command value was 436 var. The single-phase AC voltage at the AC terminal of the single-phase voltage type AC / DC converter was almost the same as the power command vector 100 ms after PQ control was started. The output current waveform was a sine wave with little distortion.

  The above single-phase voltage type AC / DC converter includes an inverter for photovoltaic power generation, an inverter for fuel cell, an inverter for power storage system, an inverter for wind power generation with DC link, a rectifier, and an SVC (reactive power compensation device). ) Etc.

11: Single-phase voltage type AC / DC converter 21: DC terminal 22: AC terminal 30: Phase difference generation circuit 31: Output voltage detection circuit 33-1 to 33-3: Terminal 34: Output current detection circuit 35: Phase delay single phase AC generator 36: phase difference voltage generator 38: current transformer 40: single phase voltage type AC / DC converter circuit 40-1, 40-2: single phase voltage type AC / DC converter circuit 41: gate signal generator 42: single phase voltage Type AC / DC converter 43: current detection circuit 44: voltage detection circuit 45: single-phase AC filter circuit 50: frequency control circuit 51: reference frequency setting unit 53: loop filter 55: time integrator 56: second adder 57: electricity Angle 58: Third adder 60: Lower voltage control circuit 61: Reference voltage setter 62: First adder 63: Third subtractor 64: Voltage controller 65: Second multiplier 66: Filter current compensator 67: PWM current deviation compensator 6 8: Feed forward amplifier 69: Fourth adder 70: Upper voltage control circuit 71a: First subtractor 71b: Second subtractor 72a: First upper control amplifier 72b: Second upper control amplifier 73: First multiplier 120 : Upper command vector 121: Limiter 130: Power command vector 140: AC power measuring device 141: Reference frequency circuit 142: Voltage phase delay circuit 143: Current phase delay circuit 144: Power calculation circuit 145: Active power value measurement circuit 146: Invalid Power value measuring circuit 147-1, 147-2, 147-3, 147-4: multiplier 148-1: adder 148-2: subtractor 149-1, 149-2: low pass filter 150: power control circuit B1 : Upper command vector B2: Most significant control block B3: ac-AVR block B4: ETM-PWM block B5: Main switch

Claims (2)

The AC terminal has an internal electromotive voltage and an internal equivalent impedance as viewed from the AC terminal, and converts the voltage from the DC voltage source into a single-phase AC voltage according to the pulse width of the gate signal generated based on the PWM command. Single-phase voltage type AC / DC converter circuit that outputs from
A power command vector comprising an active power command value for the active power value of the single-phase output power of the AC terminal and a reactive power command value for the reactive power value is input, and the power command vector, the effective power of the single-phase output power of the AC terminal Based on the power value and the reactive power value of the single-phase output power of the AC terminal, the power generated so that the active power value and reactive power value of the single-phase output power of the AC terminal approaches the command value by the power command vector A power control circuit that outputs a control signal as an upper command vector comprising a voltage amplitude command value for the amplitude of the single-phase AC voltage at the AC terminal and a frequency command value for the frequency;
A phase-delayed single-phase AC generator that delays the phase of the single-phase AC voltage of the AC terminal and generates a delayed single-phase AC, and based on the delayed single-phase AC, the single-phase AC voltage of the AC terminal and the A phase difference generation circuit for generating a voltage corresponding to the phase difference from the internal electromotive voltage of a single-phase voltage type AC / DC conversion circuit;
Based on the upper command vector from the power control circuit, the voltage corresponding to the phase difference from the phase difference generation circuit, and the single-phase AC voltage at the AC terminal, the amplitude and frequency of the single-phase AC voltage at the AC terminal are An upper voltage control circuit that outputs a voltage command signal and a frequency command signal generated so as to approach the command value by the upper command vector;
The single-phase voltage type AC / DC conversion based on a reference frequency defining the frequency of the single-phase AC voltage of the AC terminal, a frequency command signal from the higher voltage control circuit, and a voltage corresponding to the phase difference from the phase difference generation circuit A frequency control circuit for generating an electrical angle of the internal electromotive voltage of the circuit;
A reference voltage serving as a reference for the amplitude of the single-phase AC voltage of the AC terminal is set, and a value obtained by multiplying the reference voltage by a signal based on the electrical angle from the frequency control circuit and the reference voltage is set. A single-phase voltage type AC / DC converter having a lower voltage control circuit that adds a voltage command signal as the internal electromotive voltage and outputs a difference between the internal electromotive voltage and the single-phase AC voltage as the PWM command. ,
A distributed power source inverter using a DC voltage source as a fuel cell or a power storage system that outputs a DC voltage, or a voltage source that outputs a DC voltage generated and rectified by a power generation method of solar power generation or wind power generation. The AC terminal has an internal electromotive voltage and an internal equivalent impedance as viewed from the AC terminal, and converts the voltage from the DC voltage source into a single-phase AC voltage according to the pulse width of the gate signal generated based on the PWM command. Single-phase voltage type AC / DC conversion process output from
A power command vector comprising an active power command value for the active power value of the single-phase output power of the AC terminal and a reactive power command value for the reactive power value is input, and the power command vector, the effective power of the single-phase output power of the AC terminal Based on the power value and the reactive power value of the single-phase output power of the AC terminal, the power generated so that the active power value and reactive power value of the single-phase output power of the AC terminal approaches the command value by the power command vector A power control step of outputting a control signal as an upper command vector comprising a voltage amplitude command value for the amplitude of the single-phase AC voltage at the AC terminal and a frequency command value for the frequency;
The phase of the single-phase AC voltage of the AC terminal is delayed, a delayed single-phase AC is generated, and the single-phase AC voltage of the AC terminal and the internal of the single-phase voltage type AC / DC converter circuit based on the delayed single-phase AC A phase difference generation step for generating a voltage corresponding to the phase difference from the electromotive voltage;
Based on the upper command vector generated in the power control step, the voltage corresponding to the phase difference generated in the phase difference generation step, and the single-phase AC voltage of the AC terminal, the single-phase AC voltage of the AC terminal An upper voltage control step for outputting a voltage command signal and a frequency command signal generated so that an amplitude and a frequency approach a command value by the upper command vector;
The single-phase voltage type based on a reference frequency that defines the frequency of the single-phase AC voltage of the AC terminal, a frequency command signal output in the higher voltage control step, and a voltage corresponding to the phase difference generated in the phase difference generation step A frequency control step of generating an electrical angle of the internal electromotive voltage of the AC / DC converter circuit;
A reference voltage serving as a reference for the amplitude of the single-phase AC voltage of the AC terminal is set, and the higher voltage control step is a value obtained by multiplying the reference voltage by the signal based on the electrical angle generated in the frequency control step. A lower voltage control step of adding the voltage command signal output in step S3 to obtain the internal electromotive voltage, and outputting the difference between the internal electromotive voltage and the single-phase AC voltage as the PWM command;
With
A control method for an inverter for a distributed power source, wherein a DC voltage source is a voltage source that outputs a DC voltage generated and rectified by a fuel cell or a power storage system that outputs a DC voltage, or a power generation method of solar power generation or wind power generation.

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