JP2014072981A - Single-phase voltage type ac-dc conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-phase voltage type AC-DC conversion device that enables such an autonomous parallel operation that an individual device autonomously controls an output deviation even in the case that a plurality of devices are connected in parallel to perform a parallel operation by a single-phase AC, and that can independently control an active power and a reactive power respectively.SOLUTION: A single-phase AC having a predetermined phase difference from a phase of a single-phase AC voltage of an AC terminal is generated, and the generated single-phase AC and the single-phase AC voltage of the AC terminal are utilized to perform PWM control of an inverter. In addition, an active power and a reactive power of the AC terminal are measured, and a single-phase voltage type AC-DC conversion circuit is controlled so as to obtain the desired active power and reactive power.

Description

  The present invention relates to a single-phase voltage type AC / DC converter that can be applied to a grid interconnection device or an uninterruptible power supply as a power source for a power system.

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 JP 2009-201224 A

  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 to provide a single-phase voltage type AC / DC converter that can be controlled independently.

  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 single-phase voltage type AC / DC converter of the present invention controls the first axis and the second axis independently, and uses the inherent electrical angle generated by the frequency control circuit to follow the single-phase AC voltage to the frequency of the power system. Further, the active power and reactive power of the AC terminal are measured, and the single-phase voltage type AC / DC converter circuit is controlled so as to obtain the desired active power and reactive power.

Specifically, the single-phase voltage type AC / DC converter according to the present invention has an internal electromotive voltage and an internal equivalent impedance when viewed from the AC terminal, and applies a single-phase voltage from a DC voltage source according to the pulse width of the gate signal. A single-phase voltage type AC / DC converter that converts and outputs an AC voltage, a current that detects a single-phase AC current of the single-phase voltage type AC / DC converter and outputs a signal generated according to the magnitude of the single-phase AC current An allowable value for a difference between the detection circuit and an input PWM command and an output from the current detection circuit is set in advance, the difference is sampled at a predetermined period, and the difference is the allowable value for each sampling. A single-phase voltage type AC / DC converter that outputs the single-phase AC voltage output from the single-phase voltage type AC / DC converter from the AC terminal. Times And,
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;
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;
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 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;
Is provided.

The single-phase voltage type AC / DC converter according to the present invention has an internal electromotive voltage and an internal equivalent impedance when 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. A single-phase voltage type AC / DC converter that converts and outputs, a voltage detection circuit that detects a single-phase AC voltage of the single-phase voltage type AC / DC converter and outputs a signal generated according to the magnitude of the single-phase AC voltage; And an allowable value for the difference between the input PWM command and the output from the voltage detection circuit is set in advance, the difference is sampled at a predetermined period, and the difference is within the allowable value every sampling. A single-phase voltage-type AC / DC conversion circuit that outputs the single-phase AC voltage output from the single-phase voltage type AC / DC converter from the AC terminal;
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;
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;
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 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;
Is provided.

  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 according to the present invention can be operated by being connected to the power system as a voltage source, and autonomous parallel operation for autonomously compensating for the voltage deviation with respect to the power system is possible. It is. 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 higher command vector based on the output power vector, the single-phase voltage type AC / DC converter according to the present invention has the target values of the active power and reactive power of the single-phase output power. 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. And a single-phase voltage type AC / DC converter that can be controlled independently.

Furthermore, the single-phase voltage type AC / DC converter according to the present invention samples the difference between the PWM command and the output from the current detection circuit or the voltage detection circuit at a predetermined period in the single-phase voltage type AC / DC converter circuit, An error tracking method is employed in which a gate signal is generated so that the output current of the single-phase voltage type AC / DC converter approaches the PWM command. For this reason, the single phase voltage type | mold AC / DC converter which concerns on this invention also has the following characteristics.
(1) An arbitrary current waveform can be used as a target function of alternating current regardless of whether it is steady or transient. This single-phase voltage type AC / DC converter can be operated autonomously in parallel by setting the AC current of the power system connected to the AC terminal as a target function.
(2) It is ensured that the tracking error of the actual AC current with respect to the target function always falls within a predetermined error range (allowable value) instantaneously and instantaneously.
(3) Since the control device is fully digitalized, all control software can be realized.
(4) Since it is a fixed period sampling method, there is no limit cycle that is pointed out in the hysteresis comparator method. The limit cycle is a phenomenon such as oscillation in which a signal value reciprocates within a limit, and is a phenomenon unique to a nonlinear circuit.

Each structure of the single phase voltage type | mold AC / DC converter which concerns on this invention is demonstrated more concretely. 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 single-phase AC voltage of the AC terminal from the signal output from the first subtractor 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 high-order control amplifier that amplifies a signal and outputs it as the voltage command signal; a second subtracter that subtracts a voltage corresponding to the phase difference from the phase difference generation circuit from the high-order command vector; and A second upper control amplifier that amplifies a signal from the second subtractor and outputs the signal as the frequency command signal so that a single-phase AC voltage approaches the command value by the upper command vector. ,
The lower voltage control circuit multiplies a reference voltage setter that sets and outputs 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.
The frequency control circuit includes a second adder for adding a frequency command signal from the higher voltage control circuit and a voltage corresponding to the phase difference from the phase difference generation circuit, and a signal output from the second adder. A loop filter for adding a low-pass filter element to the frequency component for output; a reference frequency setter for setting the reference frequency; and a third addition for adding 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.

  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 power 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 according to the present invention 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. And a single-phase voltage type AC / DC converter that can be controlled 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 according to the present invention further comprises an output current detection circuit for detecting a single-phase AC current of the AC terminal,
The lower voltage control circuit includes a filter current compensator that outputs a current compensation value defined to compensate for a current loss in a single-phase AC filter circuit included in the single-phase voltage type AC / DC converter circuit, and the single-phase voltage A PWM current deviation compensator that outputs a current deviation compensation value defined so as to compensate for the current deviation of the single-phase AC current from the AC / DC conversion circuit, and the value of the single-phase AC current detected by the output current detection circuit is A feedforward amplifier that is input and amplifies and outputs with a predetermined feedforward gain so as to compensate the current for the load on the AC terminal, a current compensation value of the filter current compensator, and a current from the PWM current deviation compensator A fourth adder for adding a deviation compensation value and an output value from the feedforward amplifier to a PWM command value from the voltage controller; Desirable.

  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 according to the present invention, the phase-lag single-phase AC generator of the phase difference generation circuit delays the phase of the delayed single-phase AC by 90 ° from the single-phase AC voltage of the AC terminal. Features.

  The power control circuit of the single-phase voltage type AC / DC converter according to the present invention integrates the difference between the power command vector and the single-phase output power measurement value of the AC terminal and low-pass filters the power control signal. It is desirable to generate. 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 according to the present invention 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 input to the upper voltage control circuit via the limiter. desirable.

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

  In the single-phase voltage type AC / DC converter according to the present invention, 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 according to the present invention, the target values of the active power and reactive power of the single-phase output power are given as the command values. Therefore, if the active power command value of the power command vector is zero, the reactive power Operation is possible with a power factor of zero for non-interference with the command value. On the other hand, if the reactive power command value of the power command vector is zero, operation is possible with a power factor of 1 for non-interference with the active power command value. is there.

  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 A single-phase voltage type AC / DC converter that can be controlled independently can be provided.

It is a schematic block diagram of the single phase voltage type | mold AC / DC converter which concerns on this invention. It is a schematic block diagram of the single phase voltage type | mold AC / DC converter which concerns on this invention. It is a schematic block diagram of the single phase voltage type | mold AC / DC converter which concerns on this invention. It is a schematic block diagram of the single phase voltage type | mold AC / DC conversion circuit with which the single phase voltage type | mold AC / DC converter 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 the single phase voltage type | mold AC / DC converter which concerns on this invention is provided. It is a schematic block diagram of the alternating current power measuring device with which the single phase voltage type | mold AC / DC converter which concerns on this invention is provided. It is a schematic block diagram of the alternating current power measuring device with which the single phase voltage type | mold AC / DC converter which concerns on this invention 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 relation of the control block in the single phase voltage type | mold AC / DC converter which concerns on this invention. It is a schematic block diagram of the phase difference production | generation circuit with which the single phase voltage type | mold AC / DC converter which concerns on this invention is provided. It is the equivalent circuit which looked at the single phase voltage type | mold AC / DC converter which concerns on this invention from the alternating current terminal. It is a schematic block diagram of the single phase voltage type | mold AC / DC conversion part with which the single phase voltage type | mold AC / DC converter which concerns on this invention is provided. It is a schematic block diagram of the single phase alternating current filter circuit with which the single phase voltage type | mold AC / DC converter which concerns on this invention 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. 11 is an equivalent circuit viewed from the AC terminal of the static reactive power compensator. In FIG. 11, Vco (t) is an internal electromotive voltage, Ri is a resistance component of internal equivalent impedance, and Li is an inductance component of internal equivalent impedance.

  FIG. 9 is a diagram illustrating a connection relationship of control blocks in the single-phase voltage type AC / DC converter. 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 the single-phase voltage type AC / DC converter 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 the voltage into a single-phase AC voltage, and outputs it from the AC terminal 22;
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 is input, and the power command vector 130 and the single-phase output power of the AC terminal 22 Based on the active power value and the reactive power value of the single-phase output power of the AC terminal 22, the active power value and the reactive power value of the single-phase output power of the AC terminal 22 are generated so as to approach the command value by the power command vector 130. A power control circuit 150 that outputs a power control signal as a high-order command vector 120 comprising a voltage amplitude command value for the amplitude of the single-phase AC voltage at the AC terminal 22 and a frequency command value for the frequency;
A phase-delayed single-phase alternating current generator for generating a delayed single-phase alternating current whose phase is delayed with respect to the single-phase alternating current voltage at the alternating current terminal 22, and a single-phase alternating current voltage at the alternating current terminal 22 based on the delayed single-phase alternating current; And a phase difference generation circuit 30 for generating a voltage corresponding to the phase difference between the internal voltage of the single-phase voltage type AC / DC conversion circuit 40, and
Based on the upper command vector 120 from the power control circuit 150, the voltage corresponding to the phase difference from the phase difference generation circuit 30, and the single-phase AC output of the AC terminal 22, the amplitude and frequency of the single-phase AC voltage at the AC terminal 22 are An upper voltage control circuit 70 for outputting a voltage command signal and a frequency command signal generated so as to approach the command value by the upper command vector 120;
An electrical angle is generated 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 higher voltage control circuit 70, and a voltage corresponding to the phase difference from the phase difference generation circuit 30. A frequency control circuit 50 for synchronizing the electrical angle of the internal electromotive voltage of the single-phase voltage type AC / DC converter circuit 40 to the corner;
Based on the single-phase AC voltage at the AC terminal 22, the generated value from the frequency control circuit 50, and the voltage command signal from the upper voltage control circuit 70, the amplitude, frequency and phase of the single-phase output voltage are single-phase AC at the AC terminal 22. A lower voltage control circuit 60 that outputs a reference voltage that defines the amplitude of the voltage, a signal generated so as to approach the combined value of the voltage command signal and the generated value 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 converter 42 that receives the signal and converts it into a single-phase AC voltage and outputs it, and detects the single-phase AC current of the single-phase voltage-type AC / DC converter 42 and outputs a signal generated in accordance with the magnitude. An allowable value for the difference between the current detection circuit 43 and the input PWM command and the output from the current detection circuit 43 is set in advance, the difference is sampled at a predetermined period, and the difference is calculated for each sampling. A gate signal generator 41 that generates and outputs a gate signal so as to be within an allowable value is provided. The gate signal generator 41 receives a timing pulse every sampling period. The allowable value and the sampling period for the difference are set according to specifications required for the single-phase voltage type AC / DC converter 11. Further, the single-phase voltage type AC / DC converter circuit 40-1 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 single-phase voltage type AC / DC converter 42 and outputs it. And a single-phase AC filter circuit 45.

  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 is preset with an allowable value for the difference between the input PWM command and the output from the voltage detection circuit 44, and samples the difference at a predetermined cycle. A gate signal is generated and output so that the difference falls within the allowable value.

  The internal equivalent impedance of the single-phase voltage type AC / DC converter 42 shown in FIG. 4 and FIG. 5 can be given by a control variable in the single-phase voltage type AC / DC converter 11 of FIG. 4 and the output of the single-phase voltage type AC / DC converting circuits 40-1 and 40-2 in FIG. 5 may be provided with 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.

  Here, in FIG. 12, the schematic block diagram of the single phase voltage type | mold AC / DC conversion part in FIG.4 and FIG.5 is shown. FIG. 13 shows a schematic configuration diagram of the single-phase AC filter circuit in FIGS. 4 and 5.

  The single-phase voltage type AC / DC converter 42 shown in FIG. 12 includes four self-extinguishing switches 46g, 46h, 46k, 46l and four diodes 46a, 46b, 46e, 46f. The self-extinguishing type switches 46g, 46h, 46k, and 46l are elements that switch on / off according to on / off of an input signal. MOSFETs (MOS type field effect transistors) and IGBTs (insulated gate bipolar transistors) are used. It can be illustrated. The single-phase voltage type AC / DC converter 42 receives a gate signal from the gate signal generator 41 shown in FIG. 4 or 5 as an input signal. The single-phase voltage type AC / DC converting unit 42 switches on / off of the four switches according to the gate signal for each of the four self-extinguishing type switches 46g, 46h, 46k, and 46l by the pulse signal, so that the DC voltage source 23 Can be converted into a single-phase AC voltage and output from the AC terminals 24 and 26. The output voltage can be changed by changing the pulse width of the pulse signal. In FIG. 12, DC terminals 21-1 and 21-2 correspond to the DC terminal 21 of FIG.

  The single-phase AC filter circuit 45 shown in FIG. 13 receives the single-phase output from the single-phase voltage type AC / DC converter 42 of FIG. 4 or 5 at the AC terminals 24 and 26 on the input side, and outputs the AC terminal 22− on the output side. Between the output from 1 and 22-3, it has the inductor 47d which controls an electric current, the resistance 47a connected between AC terminal 22-1 and AC terminal 22-3, and the capacitor | condenser 47g. The capacitances of the inductor 47d, the resistor 47a, and the capacitor 47g can be determined as appropriate according to the frequency characteristics of the output signals from the output-side AC terminals 22-1 and 22-3. The resistor 47a may be omitted and the capacitor 47g may be connected between the AC terminal 22-1 and the AC terminal 22-3. In the single-phase voltage type AC / DC conversion circuits 40-1 and 40-2 of FIGS. 4 and 5, the single-phase voltage type AC / DC conversion unit 42 is applied by applying the single-phase AC filter circuit 45 of FIG. 13 as the single-phase AC filter circuit 45. It is possible to remove high-frequency components resulting from the gate signal at. In FIG. 13, AC terminals 22-1 and 22-3 correspond to the AC terminal 22 of FIG.

  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 shown in FIG. 1 detects a single-phase AC current at 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.

  As a result, even if the amplitude and frequency of the power system change, it is possible to detect respective errors in the amplitude and frequency of the single-phase output power of the single-phase voltage type AC / DC converter 11 with respect to the amplitude and frequency. 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 the voltage command signal from the higher voltage control circuit 70 and the signal output from the second multiplier 65 and outputs the result. A signal output from the first adder 62 corresponds to the 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.

(Internal electromotive force calculation method)
First, the output voltage detection circuit 31 detects the voltage V _FIL (t) at the AC terminal 22. This detected value is input to the phase difference generation circuit 30 and a phase-lag single-phase AC voltage V ″ _FIL (t) whose phase is delayed by 90 degrees is generated by the phase-lag single-phase AC generator 35 ( _Equation 2). The phase difference voltage generator 36 generates a phase difference voltage Vq (t) using V _FIL (t), V ″ _FIL (t) and a phase (generated electrical angle) θ _i of an internal electromotive voltage described later ( Equations 3 and 4).

Subsequently, V _q (t) and the frequency command value from the second upper control amplifier 72b are added and passed through the loop filter 53, and a preset reference angular frequency ω _co is added and passed through the integration circuit 55. Thus, the phase angle (generated electrical angle 57) θ _i of the internal electromotive voltage is obtained. On the other hand, multiplying the reference voltage E _co and √2Sinshita _i that is set in advance, it calculates the internal electromotive voltage by adding the voltage command value from the first upper control amplifier 72a.

In this way, the internal electromotive force can be calculated using the voltage V _FIL (t) of the AC terminal 22, the reference angular frequency ω _co , the reference voltage E _co , the frequency command value, and the voltage command value.

(Overview of operation)
During the self-sustained operation, that is, when the internal electromotive voltage V _co (t) and the voltage V _FIL (t) of the AC terminal 22 coincide with each other, the output of the third subtracter 63 becomes zero and the PWM command becomes the zero command. At this time, the AC voltage source E operates with the internal electromotive voltage V _co (t). On the other hand, at the time of grid connection operation, that is, when the internal electromotive voltage V _co (t) and the voltage V _FIL (t) of the AC terminal 22 deviate from each other, the output of the third subtractor 63 outputs the deviation amount, and the voltage control The device 64 outputs a PWM command for converging the deviation. At this time, the AC voltage source E operates so that the internal electromotive voltage V _co (t) approaches the voltage V _FIL (t).

  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 current of the AC terminal 22 detected by the output current detection circuit 34. 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 alternating 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. Further, the feedforward amplifier 68 receives the value of the single-phase alternating 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 of the alternating current terminal 22, and outputs it. Thus, in the single-phase voltage type AC / DC converter 11, the output current detection circuit 34 detects the single-phase alternating current at the alternating-current terminal 22, and the value is converted to the output value from the voltage controller 64 through the feedforward amplifier 68. By adding, 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 output power 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 starting the PQ control. The output current waveform was a sine wave with little distortion.

  A single-phase voltage type AC / DC converter according to the present invention includes an inverter for photovoltaic power generation, an inverter for fuel cell, an inverter for storage system, an inverter for wind power generation with DC link, a rectifier, and SVC (reactive power compensation). Device).

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 (8)

A single-phase voltage type AC / DC converter that has an internal electromotive voltage and an internal equivalent impedance when 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, A current detection circuit that detects a single-phase alternating current of a phase voltage type AC / DC converter and outputs a signal generated according to the magnitude of the single-phase alternating current; and an input PWM command and an output from the current detection circuit; A gate signal generator configured to sample the difference at a predetermined period, generate the gate signal so that the difference falls within the tolerance for each sampling, and output the gate signal. A single-phase voltage type AC / DC conversion circuit that outputs the single-phase AC voltage output by the single-phase voltage type AC / DC converter from the AC terminal;
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;
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;
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 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 single-phase voltage type AC / DC converter. A single-phase voltage type AC / DC converter that has an internal electromotive voltage and an internal equivalent impedance when 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, A voltage detection circuit that detects a single-phase AC voltage of a phase voltage type AC / DC converter and outputs a signal generated according to the magnitude of the single-phase AC voltage, and an input PWM command and an output from the voltage detection circuit A gate signal generator configured to sample the difference at a predetermined period, generate the gate signal so that the difference falls within the tolerance for each sampling, and output the gate signal. A single-phase voltage type AC / DC conversion circuit that outputs the single-phase AC voltage output by the single-phase voltage type AC / DC converter from the AC terminal;
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;
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;
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 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 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 a signal output from the first multiplier that simply outputs the AC terminal. A first subtractor for subtracting a phase AC voltage, and amplifying the 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 as the voltage command signal A first upper control amplifier for outputting, a second subtracter for subtracting a voltage corresponding to the phase difference from the phase difference generation circuit from the upper command vector, and a single-phase AC voltage at the AC terminal according to the upper command vector. A second upper control amplifier that amplifies the signal from the second subtractor so as to approach the command value and outputs the signal as the frequency command signal;
The lower voltage control circuit multiplies a reference voltage setter that sets and outputs 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.
The frequency control circuit includes a second adder for adding a frequency command signal from the higher voltage control circuit and a voltage corresponding to the phase difference from the phase difference generation circuit, and a signal output from the second adder. A loop filter for adding a low-pass filter element to the frequency component for output; a reference frequency setter for setting the reference frequency; and a third addition for adding the output value of the reference frequency setter to the output value of the loop filter 3. The single-phase voltage type AC / DC converter according to claim 1, further comprising a time integrator that time-integrates a signal output from the third adder and outputs the signal as the electrical angle. . An output current detection circuit for detecting a single-phase AC current of the AC terminal;
The lower voltage control circuit includes a filter current compensator that outputs a current compensation value defined to compensate for a current loss in a single-phase AC filter circuit included in the single-phase voltage type AC / DC converter circuit, and the single-phase voltage A PWM current deviation compensator that outputs a current deviation compensation value defined so as to compensate for the current deviation of the single-phase AC current from the AC / DC conversion circuit, and the value of the single-phase AC current detected by the output current detection circuit is A feedforward amplifier that is input and amplifies and outputs with a predetermined feedforward gain so as to compensate the current for the load on the AC terminal, a current compensation value of the filter current compensator, and a current from the PWM current deviation compensator A fourth adder for adding a deviation compensation value and an output value from the feedforward amplifier to a PWM command value from the voltage controller; Single-phase voltage-type AC-DC converter according to claim 3, characterized. The phase delay single-phase AC generator of the phase difference generation circuit is:
5. The single-phase voltage type AC / DC converter according to claim 1, wherein the phase of the delayed single-phase AC is delayed by 90 ° from the single-phase AC voltage of the AC terminal.   The power control circuit 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. The single phase voltage type | mold AC / DC converter in any one of.   7. The single unit according to claim 1, further comprising a limiter that determines an upper limit and a lower limit of the upper command vector, wherein the upper command vector is input to the upper voltage control circuit via the limiter. Phase voltage AC / DC converter.   8. The single-phase voltage type AC / DC converter according to claim 1, wherein either one of the active power command value and the reactive power command value of the power command vector is zero. 9.

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