JP2009225599A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converter used in a power storage system, capable of burdening a harmonic component and an imbalance content of a load current without separately installing detection means for a load current or the like. <P>SOLUTION: The power conversion apparatus is provided with a power conversion unit 3 which can convert DC power of a secondary battery 1 into AC power, convert AC power input through an output line into DC power and store the DC power in the secondary battery 1. A control unit 12 is previously installed with a virtual power generator instead of the power conversion unit 3 and the secondary battery 1. The control unit 12 includes: a virtual power generator model unit 13 which calculates a current value to be output based on the voltage of the output line of the power conversion unit 3 and sets the current value as a current command value; and a control signal generation unit 20 for outputting current corresponding to the current command value to the output line. Further, in the virtual power generator model unit 13, an engine model 60 calculates the angular velocity ωe and phase angle θm of a generator using the amount F of fuel supply calculated in a governor model 80 to be converted into the mechanical torque of an engine without consideration of the response characteristics of the engine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power conversion device used for a microgrid (small power distribution network) or the like.

  In recent years, there has been an increasing interest in power supply systems that use distributed power sources such as gas engine generators and fuel cells. For example, in a specific area, a system called a microgrid has been proposed that uses the above-described power generation device called a distributed power source and supplies power from the power generation device to a plurality of loads. In such a microgrid, in addition to the above-described power generation device, a power storage device including a secondary battery is connected to the internal power system in order to compensate for fluctuations in generated power and load fluctuations of the power generation device. Are often configured. Moreover, about the microgrid, the form operate | moved independently with a commercial power system and the form operate | moved in connection with a commercial power system are considered. In a system using such a distributed power source, it is important to realize a stable power supply.

  For example, Patent Documents 1, 2, and 3 disclose a configuration that includes a power generation device and a power storage device that are linked to a commercial power system.

  Furthermore, Patent Document 2 discloses a technique for suppressing power oscillation and power fluctuation of an internal power system at the time of transition to independent operation by detecting effective power of a load and controlling charge / discharge of a power storage device. Has been.

  Patent Document 3 discloses a technique for detecting a generator output, load power, and the like in a private power generation facility, and controlling the generator output and the output from the secondary battery according to the power demand of the load. Yes.

  Patent Document 4 discloses a reactive power compensator that compensates reactive power generated by a load connected to an electric power system with a voltage-type self-excited inverter, and detects the load current, thereby converting it into a three-phase unbalanced component of the load current. A technique for suppressing the voltage fluctuation of the electric power system generated due to this is disclosed.

  Further, Patent Document 5 describes an active filter having a configuration in which a plurality of filters are combined and selectively functioned by a switch to detect a load current, a harmonic current of the load current, a three-phase unbalanced component, and the like. A technique for compensating for the above is disclosed.

  By the way, the power storage device used for the microgrid includes a power storage unit such as a secondary battery, and a power conversion device using a current type inverter that charges and discharges the power of the power storage unit to and from the power system. However, in general power converters, current-type inverters are controlled to output a certain command value regardless of the state of the power system. There is a problem that the load on the power generation device is increased without burdening the balance.

  Patent Document 1 does not disclose a technique for solving the above problems.

  Although it is considered that the above-described problems can be solved to some extent by using the techniques of Patent Documents 2 and 3, it is necessary to detect the effective power of the load and the like, and a detection means for that purpose is required.

  Further, it is considered that the above-described problems can be solved to some extent by using the techniques of Patent Documents 4 and 5. However, Patent Documents 4 and 5 disclose a dedicated device for solving a specific problem. It is necessary to install the device separately. Also in the apparatus, means for detecting the load current is necessary.

Then, in order to solve such a subject, the power converter device described in patent document 6 is proposed. According to this power conversion device, it is possible to bear a harmonic component and an unbalanced portion of the load current without separately providing a detection means such as a load current.
JP 2004-064810 A JP 2004-147445 A JP 2001-112176 A JP-A-7-67255 JP-A-8-65892 JP2007-244068

  However, the power conversion device has a problem that the characteristics (primary delay) of the prime mover complicate the behavior of the virtual power generation device model unit, and the response speed of the virtual power generation device model unit is not necessarily high.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a power conversion device in which the response speed of the virtual power generation device model unit is high.

  In order to solve the above-described problems, a power converter according to the present invention converts DC power of a secondary battery into AC power, outputs the AC power to an output line connected to the AC circuit, and outputs the output line from the AC circuit. A power conversion unit capable of converting AC power input via DC to DC power and storing it in the secondary battery, and a control unit for controlling the power conversion unit, the control unit, When it is assumed that a virtual power generation device that is an imaginary power generation device is provided in advance instead of the power conversion unit and the secondary battery, and an output line of the power conversion unit is an output line of the virtual power generation device And calculating a current value to be output by the virtual power generation device based on the voltage of the output line of the power conversion unit, and setting the calculated current value as a current command value to the current command value. Output the corresponding current to the output line. A power conversion control unit that controls the power conversion unit by current feedback control so that the virtual power generation device model unit includes the virtual power generation device, the generator, and the field voltage of the generator. The generator, the AVR, the prime mover, and the governor are assumed to include an AVR that controls the generator, a prime mover that drives the generator, and a governor that controls the amount of fuel supplied to the prime mover. There are a generator model, an AVR model, a prime mover model, and a governor model that define each input / output relationship. The AVR model includes a voltage of an output line of the power converter, a reactive power command value given from the outside, and the The field voltage of the generator is calculated based on the voltage command value of the output line, and the governor model is calculated by the prime mover model. The fuel supply amount to the prime mover is calculated based on the angular velocity of the electric machine, the active power command value given from the outside, and the active power command value of at least the angular velocity command value of the generator, The prime mover model calculates the angular velocity and phase angle of the generator based on the fuel supply amount calculated by the governor model and the electric torque of the generator calculated by the generator model. The generator model is configured such that the voltage of the output line of the power converter, the field voltage of the generator calculated by the AVR model, and the angular velocity of the generator calculated by the prime mover model And the electric torque of the generator, which is a mechanical load of the prime mover, and the direct axis current value and the horizontal axis current value output from the generator, based on the phase angle and the calculated direct axis current value and And the horizontal axis current value is determined to be the current command value, and the prime mover model is configured so that the fuel supply amount calculated by the governor model is determined without considering the response characteristics of the prime mover. It is configured to calculate the angular velocity and phase angle of the generator by using it converted into mechanical torque.

  Here, when the current value (current command value) to be output by the virtual power generation device calculated by the virtual power generation device model unit is a negative current value, the virtual power generation device is in the operation area as an electric motor and is input. The secondary battery is charged with the electric power.

  According to this configuration, the current value to be output by the virtual power generator is calculated based on the voltage of the output line connected to the AC circuit, in other words, based on the voltage of the AC circuit, and the current command value is supported. Since the power conversion unit is controlled so as to output the current to be output, the current output from the power conversion unit is controlled in the same manner as the current output from the normal power generator. Therefore, even if a load and a power generation device are connected to the AC circuit, and the load current contains a harmonic component or an unbalanced state occurs, the power conversion device, as a result, has the same harmonics as the power generation device. Since the wave current and the unbalanced current are output, the harmonic component and the unbalanced component can be borne together with the power generator, and the burden on the power generator can be reduced. Further, in this case, a means for detecting the voltage and current of the output line of the power conversion unit is necessary, but such a detection means is provided as an internal component of the power converter and is connected to a load connected to the AC circuit. It is not necessary to separately provide the current and power detection means. Furthermore, the output of the power conversion device can be controlled in the same manner as the output of the power generation device having the generator and the prime mover and the AVR and governor that controls them. Furthermore, when the AC circuit to which the output line of the power conversion unit of the power conversion device of the present invention is connected is connected to the circuit of the large-scale power system through the circuit breaker, the circuit breaker is closed, Even when the AC circuit is connected to the power circuit of the large-scale power system (connected state), the circuit breaker is opened and the AC circuit is disconnected from the circuit of the large-scale power system (connected) In the power conversion device of the present invention, the current output from the power conversion unit is controlled in the same way as the current output from the normal power generation device even in the system shutdown state). Therefore, it is possible to stabilize the power quality of the own system (AC circuit). Further, even when transitioning from the connected state to the disconnected state, it is possible to stabilize the power quality of the own system in a transient manner in cooperation with a normal power generator. Further, the prime mover model converts the fuel supply amount calculated by the governor model into the mechanical torque of the prime mover without considering the response characteristic of the prime mover, and calculates the angular velocity and phase angle of the generator. Since it is configured, the response speed of the virtual power generation device model section is increased, and the model order is decreased to facilitate adjustment.

  The virtual power generation device model section has a reactance that cancels a reactance component of the load in parallel with the load on the AC circuit in the generator model when the power factor of the load on the AC circuit is lower than a predetermined value. It may be configured to behave as if a load is connected. According to this configuration, it is possible to prevent the occurrence of problems due to the armature reaction in the generator model.

  The virtual power generation device model unit is configured to have a startup operation and a normal operation after the startup operation is completed, and the AVR model is configured such that the voltage of the output line and the output in the startup operation of the power converter A field voltage of the generator is calculated using a predetermined voltage instead of at least one of the voltage command values of the line, and the voltage of the output line of the power conversion unit and the output in normal operation of the power conversion unit The field voltage of the generator may be calculated based on the voltage command value of the line. According to this configuration, by appropriately selecting a predetermined voltage, it is possible to prevent an excessive current from being output from the power conversion unit during the startup operation of the virtual power generation device model unit.

  The predetermined voltage may be a terminal voltage of the generator calculated based on a voltage of an output line of the power conversion unit. According to this configuration, even if the voltage of the system fluctuates during the startup operation of the virtual power generation device model unit, it is possible to prevent an excessive current from being output from the power conversion unit.

  The virtual power generator includes phase angle limiting means for limiting the phase angle of the generator so that the absolute value of the difference angle between the phase angle of the voltage of the output line and the phase angle of the generator is a predetermined angle or less. You may be comprised so that it may have. According to this configuration, step-out can be prevented.

  The virtual power generator model unit calculates a direct axis current value and a horizontal axis current value as current values to be output by the virtual power generator, and determines the calculated direct axis current value and horizontal axis current value as the current command value. May be.

  The present invention has the above-described configuration, and in the power conversion device used in the power storage device, the load current harmonic component and the unbalanced component are borne without separately providing a load current detection means. There is an effect that can be. In addition, it can be handled without switching control methods, etc., even when connected to a large-scale power system, in the case of a connection disconnection state, or when shifting from the connection connection state to the connection disconnection state. There is an effect. Further, for example, by setting each command value input to the AVR model and the governor model and the internal setting values of the AVR model, the governor model and the prime mover model to be adjustable, they are adjusted based on the knowledge of the power generator. There is an effect that it becomes possible. Further, the response speed of the virtual power generation apparatus model section is increased and the model order is decreased, which facilitates adjustment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a circuit diagram showing a configuration example of a microgrid (small-scale power distribution network) using the power conversion device according to the embodiment of the present invention.

  In general, a microgrid is configured by connecting a power generation device including a distributed power source such as a gas engine generator or a fuel cell, a load, and a power storage device to a distribution line of the microgrid. Further, the load fluctuates due to expansion or replacement. In FIG. 1, a gas engine generator 10, a load 11, and a power storage device PS are connected to a distribution grid (AC circuit) 9 of a microgrid. In addition, the microgrid is provided with a microgrid control device 14 that manages and manages the microgrid in the area of the microgrid based on the setting of the operator operating the microgrid. Each of the power storage device PS, the gas engine generator 10 and the load 11 connected to the distribution line 9 of the microgrid is provided with a monitoring unit (measuring device for power etc .: not shown) for monitoring each situation. These monitoring units and the microgrid control device 14 can transmit and receive via a signal line (not shown), for example. The microgrid control device 14 receives the monitoring status (measured value) from each monitoring unit, and commands the output power target value and the like to the power storage device PS and the gas engine generator 10 according to the monitoring status. Send value. These command values are set (programmed) by the operator so as to be determined according to the monitoring status of each monitoring unit.

  In addition, the microgrid is operated independently of the commercial power system (large-scale power system) without being connected to the commercial power system (hereinafter referred to as “independent form”) and connected to the commercial power system. There is a form (hereinafter referred to as “interconnected form”). In the case of the interconnected form, the microgrid distribution line 9 is connected via a circuit breaker 15 to a distribution line 16 that is an electric path of a commercial power system. Even in the case of this interconnected form, when an abnormality or the like occurs in the commercial power system, the circuit breaker 15 is opened and the state is the same as in the independent form. The opening / closing of the circuit breaker 15 is controlled by, for example, a commercial power system control system (not shown). In the following, it is assumed that the system is operated in an independent form unless it is referred to as an interconnected form.

  The power storage device PS is connected to a distribution line 9 of a microgrid via a transformer 8. The power conversion device PC of the present embodiment constitutes a power storage device PS together with the secondary battery 1 such as a nickel metal hydride battery. Here, the power conversion device PC is output from the voltage sensor (voltage measurement PT) 2 that detects the voltage Vs of the secondary battery 1, the power conversion unit 3 that converts direct current into alternating current, and the power conversion unit 3. A current sensor (PT for current measurement) 4 that detects output currents ia, ib, ic of each of the three phases (a phase, b phase, c phase), an output reactor 5, and each phase (a phase, b phase) , C-phase) output voltage va, vb, vc, voltage sensor (voltage measurement PT) 6, filter capacitor 7, and control unit 12.

  The power conversion unit 3 includes six switching elements 3a to 3f each including a diode connected in antiparallel. The power conversion unit 3 is formed of a semiconductor element, and IGBTs are used for the switching elements 3a to 3f, for example. The control unit 12 outputs a control signal group Sc composed of control signals input to the control terminals (for example, the gate terminals of the IGBTs) of the respective switching elements 3a to 3f to the power conversion unit 3, and each switching element 3a to 3f is output. By performing the on / off operation, the power conversion unit 3 functions as an inverter, the DC power of the secondary battery 1 is converted into AC power and output, and the power conversion unit 3 functions as a rectifier. AC power input from 9 through the transformer 8 or the like is converted to DC power and stored in the secondary battery 1.

  The control unit 12 includes a virtual power generation device model unit 13 and a control signal generation unit (power conversion control unit) 20 that controls the power conversion unit 3 by current feedback control. The virtual power generation device model unit 13 assumes that a power generation device (virtual power generation device) is connected to the microgrid distribution line 9 in advance instead of the power storage device PS, and the assumed virtual power generation device should output. The current value is calculated, and the current value is given to the control signal generation unit 20 as the d-axis current command value Id-ref and the q-axis current command value Iq-ref. In the control signal generation unit 20, the switching elements 3 a to 3 of the power conversion unit 3 are output so that a current corresponding to the d-axis current command value Id-ref and the q-axis current command value Iq-ref is output from the power conversion unit 3. A control signal group Sc for controlling 3f is generated and output. That is, the control unit 12 controls the power conversion unit 3 so that the output current of the power conversion unit 3 is the same as the output current (calculated value) of the virtual power generator.

  The virtual power generator model unit 13 controls the generator, the AVR that controls the field voltage of the generator, the engine that drives the generator (the prime mover), and the fuel flow rate that is supplied to the engine. A generator model 30, an AVR model 70, and an engine model that define input / output relationships of the assumed generator, AVR (automatic voltage regulator), engine, and governor. (Motor model) 60 and governor model 80 are included. That is, the generator model 30 is a calculation unit that calculates an output with respect to the input of the generator, the AVR model 70 is a calculation unit that calculates an output with respect to the input of the AVR, and the engine model 60 is an output with respect to the input of the engine. The governor model 80 is a computing unit that computes the output for the governor input.

  The control unit 12 is configured by a calculation device such as a microcomputer, and the virtual power generation device model unit 13 and the control signal generation unit 20 are functions realized by executing software built in the calculation device. It is.

  As shown in FIG. 1, when only the power storage device PS, the gas engine generator 10 and the load 11 are connected to the microgrid distribution line 9, the effective power generated by the gas engine generator 10 is the load 11. When the effective power consumed in the battery is exceeded, the amount exceeding the effective power is charged in the secondary battery 1 of the power storage device PS. In this case, the power conversion unit 3 functions as a rectifier.

  Next, the configuration of the control unit 12 will be described in detail with reference to FIG. FIG. 2 is a block diagram illustrating a detailed configuration of the control unit 12. Hereinafter, an adder, a subtracter, and an adder / subtractor are referred to as an adder / subtracter without distinction.

  In addition to the generator model 30, the engine model 60, the AVR model 70, and the governor model 80, the control unit 12 includes a power calculation unit, an effective voltage calculation unit, and an angular velocity ratio calculation unit, which are not shown. The power calculation unit inputs the output currents ia, ib, ic detected by the current sensor 4 and the output voltages va, vb, vc detected by the voltage sensor 6, and calculates the active power Pg and the reactive power Qg from them. Then, the calculated active power Pg is output to the governor model 80, and the reactive power Qg is output to the AVR model 70. Here, the power calculation unit is configured to input the d-axis current command value Id-ref and the q-axis current command value Iq-ref output from the generator model 30 instead of the output currents ia, ib, ic. May be. In this case, the power calculation unit d-q reversely converts the d-axis current command value Id-ref and the q-axis current command value Iq-ref to obtain a three-phase current signal (ia-v, ib-v, ic-v). The active power Pg and the reactive power Qg are calculated from the three-phase current signals ia-v, ib-v, ic-v and the output voltages va, vb, vc. The effective voltage calculation unit receives the output voltages va, vb, vc detected by the voltage sensor 6, calculates the effective voltage Vg from them, and outputs it to the AVR model 70. The angular velocity ratio calculation unit inputs the generator angular velocity ωe, which is the output of the engine model 60, calculates the angular velocity ratio ωe / 2πf, and outputs it to the governor model 80. Here, f is a reference (rated: for example, 50 Hz) frequency, and 2πf is a reference (rated) angular velocity (fixed value). This angular velocity ratio calculation unit may be included in the governor model 80.

  In the governor model 80, the active power command value Pref and the angular velocity command value ωref are input from the external microgrid control device 14, the effective power Pg calculated by the power calculating unit is input, and the angular velocity ratio calculating unit calculates The angular velocity ratio ωe / 2πf thus input is input. The adder / subtractor 81 outputs a value obtained by subtracting the active power Pg from the active power command value Pref to the droop block 82. In the droop block 82, a value obtained by performing a predetermined operation on the output of the adder / subtractor 81 according to the droop set value is output to the adder / subtractor 85. The angular velocity ratio ωe / 2πf is input to the adder / subtractor 85 and the first-order lag calculation block 83. One of the angular velocity command value ωref and the output of the first-order lag calculation block 83 is selected by the switching circuit 84 and input to the adder / subtractor 85. The adder / subtractor 85 adds the output of the droop block 82 and the output of the switching circuit 84, and outputs a value obtained by subtracting the angular velocity ratio ωe / 2πf from the added value to the PI control block 86. In the PI control block 86, the fuel flow rate F is calculated from the output of the adder / subtractor 85 and output to the engine model 60.

  In the engine model 60, the fuel flow rate F is input from the governor model 80 and the electric torque Te is input from the generator model 30. The fuel flow rate F is directly input to the adder / subtractor 62 as the engine torque Tm. Here, “inputting the fuel flow rate F as it is as the engine torque Tm is input” means that in the virtual power generation device model 13, the input and output with respect to the configuration models 30, 60, 70, 80 are normalized, The value of the fuel flow rate F thus standardized is used as the standardized engine torque Tm. Here, “standardization” refers to a value obtained by dividing the above-mentioned physical quantity values that are the input and output by the reference value (usually the rated value). Thus, "inputting the fuel flow rate F as it is as the engine torque Tm ..." makes the engine model 60 ideal in terms of conversion from the fuel flow rate F to the engine torque Tm (the fuel flow rate F is slightly accompanied by a delay). It is linearly converted into engine torque Tm). On the other hand, when the engine model 60 is configured to faithfully simulate an actual engine, an engine characteristic block is provided, and a fuel flow rate F is input to the engine characteristic block. It is necessary to calculate the engine torque Tm in consideration of the characteristics (transfer function) and output it to the adder / subtractor 62. However, when the present inventors convert the fuel flow rate F into the engine torque Tm in consideration of the response characteristics of the engine in this way, the behavior of the virtual power generator model 13 becomes complicated, the response speed becomes slow, and the model It was confirmed by simulation that the order increased and adjustment became difficult.

  FIG. 9 is a graph showing a simulation result of the virtual power generation device model in which the engine model includes the response characteristic of the engine. FIG. 9 shows changes over time in the engine torque and the active power output from the virtual power generation device model. As shown in FIG. 9, in such a virtual power generation device model, the active power output from the virtual power generation device model vibrates with the vibration of the engine torque, and the response speed becomes slow.

  Therefore, in the present embodiment, the engine model 60 is idealized in terms of conversion from the fuel flow rate F to the engine torque Tm, and the fuel flow rate F is directly input to the adder / subtractor 62 as the engine torque Tm. As a result, the response speed is increased, and the model order is decreased to facilitate adjustment.

The adder / subtractor 62 outputs to the unit inertia constant block 63 a value obtained by subtracting the electric torque Te input from the generator model 30 and the output value of the damping block 65 from the engine torque Tm composed of the fuel flow rate F. The unit inertia constant block 63 calculates a generator angular velocity ωe by performing a predetermined calculation process using the unit inertia constant M ₀ , outputs it to the integrator 64 and the damping block 65, and generates the generator model 30 and the angular velocity ratio. Output to the calculator. In the damping block 65, a predetermined calculation process is performed using the damper coefficient D ₀ , and the output is input to the adder / subtractor 62. The integrator 64 calculates the generator internal phase angle θm from the input generator angular velocity ωe, and outputs it to the generator model 30 and the control signal generator 20 via the limiter circuit 93. The limiter circuit 93 will be described in detail later.

  In the AVR model 70, the reactive power command value Qref and the voltage command value Vref are input from the external microgrid control device 14, the reactive power Qg calculated by the power calculation unit is input, and the effective voltage calculation unit calculates it. The effective voltage Vg is input. Further, the generator terminal voltage effective value Vg-VG is inputted. The generator terminal voltage effective value Vg-VG will be described in detail later. The adder / subtractor 71 outputs a value obtained by subtracting the reactive power Qg from the reactive power command value Qref to the droop block 72. In the droop block 72, a value obtained by performing a predetermined operation on the output of the adder / subtractor 71 according to the droop set value is output to the adder / subtractor 73.

  On the other hand, the voltage command value Vref, the effective voltage Vg, and the generator terminal voltage effective value Vg-VG are input to the adder / subtractor 73 via the switching circuit 94. The switching circuit 94 will be described in detail later. During the normal operation of the virtual power generator model unit 13 (also during the normal operation of the power storage device PS), the voltage command value Vref and the effective voltage Vg are input to the adder / subtractor 73. And the voltage command value Vref are added, and a value obtained by subtracting the effective voltage Vg from the added value is output to the PI control block 73. In the PI control block 73, the field voltage Vf is calculated from the output of the adder / subtractor 73 and output to the generator model 30.

  In the generator model 30, the output voltage va, vb, vc detected by the voltage sensor 6, the field voltage Vf that is the output of the AVR model 70, the generator internal phase angle θm and the angular velocity that are the outputs of the engine model 60. ωe is input, and the electric torque Te is output to the engine model 60, and the d-axis current command value Id-ref and the q-axis current command value Iq-ref are output to the control signal generation unit 20. The generator internal phase angle θm is input to the dq conversion block 31, and the angular velocity ωe is input to the matrix calculation blocks 32, 33, 40, and 43.

  The dq conversion block 31 obtains the d-axis voltage Vd and the q-axis voltage Vq by performing dq conversion on the output voltages va, vb, and vc, and the d-axis voltage Vd is obtained from the matrix operation blocks 32 and 33 and the adder / subtractor 46. The q-axis voltage Vq is output to the matrix calculation blocks 32 and 33 and the adder / subtractor 45. In the matrix calculation block 32, the d-axis voltage Vd and the q-axis voltage Vq are input, and the outputs are output to the adder / subtractors 41 and 42. In the matrix calculation block 33, the field voltage Vf, the d-axis voltage Vd, and the q-axis voltage Vq are input, and the outputs are input to the adders / subtractors 34, 35, and 36. The adders / subtracters 34, 35, and 36 add the outputs of the matrix calculation block 33 and the outputs of the matrix calculation block 43, respectively, and output the added values to the integrators 37, 38, and 39. The outputs of the integrators 37, 38, and 39 are input to the matrix operation blocks 40, 43, and 44, respectively. The output of the matrix operation block 40 is input to adders / subtractors 41 and 42. The outputs of the adders / subtracters 41 and 42 are input to the control signal generator 20 as a d-axis current command value Id-ref and a q-axis current command value Iq-ref, respectively. The output of the adder / subtractor 42 is input to the multiplier 49, and the output of the adder / subtractor 41 is input to the multiplier 48 with its upper limit and lower limit being limited by the limiter circuit 91. Further, the amount (excess) limited by the limiter circuit 91 of the output of the adder / subtractor 41 becomes the current value ΔId-ref corresponding to the virtual load. The limiter circuit 91 will be described in detail later. The output of the matrix operation block 44 is input to adders / subtracters 45 and 46. The adder / subtracter 45 outputs a value obtained by subtracting one output of the matrix calculation block 44 from the q-axis voltage Vq to the matrix calculation block 47, and the adder / subtractor 46 outputs the other output of the matrix calculation block 44 from the d-axis voltage Vd. The subtracted value is output to the matrix calculation block 47. The two output values of the matrix operation block 47 are input to multipliers 48 and 49, respectively, and multiplied by the outputs of the adder / subtractors 41 and 42, respectively. The outputs of the multipliers 48 and 49 are input to the adder / subtracter 50, respectively. The adder / subtracter 50 subtracts the output of the multiplier 48 from the output of the multiplier 49 and outputs the value to the engine model 60 as the electric torque Te.

  The configuration of the generator model 30 is well known as described in, for example, the document “PAUL C. KRAUSE, et al: ANALYSIS OF ELECTRIC MACHINERY, IEEE Press (1995)”. Omitted.

  In the control signal generator 20, the battery voltage Vs detected by the voltage sensor 2, the output current ia, ib, ic detected by the current sensor 4, and the d-axis current command value Id− that is the output of the generator model 30. The ref and q-axis current command Iq-ref and the generator internal phase angle θm that is the output of the engine model 60 are input, and the control signal group Sc is output to the power conversion unit 3. The generator internal phase angle θm is input to the dq conversion block 21 and the dq inverse conversion block 28.

  The dq conversion block 21 obtains a d-axis current Id and a q-axis current Iq by performing dq conversion on the output currents ia, ib, and ic, and outputs them to the adders / subtracters 22 and 23, respectively. The adder / subtractor 22 subtracts the d-axis current Id from the d-axis current command value Id-ref from the generator model 30 and outputs the value to the PI control block 24. The output of the PI control block 24 is multiplied by the battery voltage Vs by the multiplier 26 and input to the dq inverse conversion block 28. The adder / subtractor 23 subtracts the q-axis current Iq from the q-axis current command value Iq-ref from the generator model 30 and outputs the value to the PI control block 25. The output of the PI control block 25 is multiplied by the battery voltage Vs by the multiplier 26 and output to the dq inverse conversion block 28. In the dq inverse conversion block 28, the outputs of the multipliers 26 and 27 are dq inversely converted and output to the PWM signal generation block 29. The PWM signal generation block 29 generates and outputs a control signal group Sc for controlling the switching elements 3 a to 3 f of the power conversion unit 3 by performing PWM processing on the output of the dq inverse conversion block 28.

  Next, the limiter circuit 91 will be described in detail. FIG. 3 is a block diagram showing the configuration of the limiter circuit 91.

  In a generator model that simply models an actual synchronous generator, as in the case of an actual synchronous generator, if the load power factor decreases, problems due to armature reaction (increase or decrease in induced electromotive force, loss of synchronization force, etc.) ) Occurs. Therefore, in the present invention, when the power factor of the load 11 is lower than a predetermined value, the virtual power generator model unit 13 has a reactance that cancels the reactance component of the load 11 in parallel with the load 11 in the generator model 30. It is configured to behave as if a virtual load is connected. Although such a configuration can be variously considered, in the present embodiment, a limiter circuit 91 that limits the d-axis current command value Id-ref used for calculation of the electric torque Te to a predetermined limit is provided. Yes.

  As shown in FIG. 3, here, the limiter circuit 91 uses the upper limit value (Id-lim) and the lower limit value-(Id-lim) as the output Id-ref of the adder / subtractor 41 used for calculating the electric torque Te. It is composed of a limiter 95 that restricts the distance between them. The output of the limiter 95 is input to the multiplier 48, and the electric torque Te is calculated using this. The upper limit value (Id-lim) and the lower limit value-(Id-lim) are acceptable when the actual load 11 and the virtual load are connected in parallel to the generator model 30 and the armature reaction caused thereby is allowed. It is determined as the d-axis current command value Id-ref corresponding to the load power factor that is the limit to be applied.

  According to this configuration, the d-axis current command value Id-ref corresponding to the reactive component (reactive current) of the shared current to be supplied to the actual load 11 is output from the generator model 30 to the control signal generator 20. Thereby, a current having an ineffective component corresponding to the d-axis current command value Id-ref is output from the power converter 3. In other words, the actual load 11 is supplied with a current that is unrelated to the presence or absence of the virtual load. On the other hand, the current value ΔId-ref corresponding to the amount limited by the limiter circuit 91 (excess) corresponds to the reactive current to be supplied to the virtual load having reactance that cancels the reactance component of the load 11. The output (Id-ref−ΔId-ref) of the limiter 95 corresponds to a reactive current (current command value) that the generator model 30 should supply to the actual load 11 and the virtual load. The electric torque Te is calculated using the output of the limiter 95, and the generator angular velocity ωe calculated by the engine model 60 using the electric torque Te is input to the generator model 30. In the AVR model 70, the field voltage Vf is calculated using the reactive power Qg corresponding to the load 11, and this field voltage Vf is input to the generator model 30. In the generator model 30, the d-axis current command value Id-ref and the q-axis current command value Iq-ref are calculated using the field voltage Vf, the electric torque Te, and the generator angular velocity ωe. That is, the virtual power generator model unit 13 behaves as if a virtual load having a reactance that cancels the reactance component of the load 11 is connected to the generator model 30 in parallel with the load 11. Therefore, even if the power factor of the load 11 decreases, the load power factor viewed from the generator model 30 does not exceed a predetermined allowable range. Increase / decrease, loss of synchronization power, etc.) can be prevented.

  Next, the limiter circuit 93 will be described in detail. FIG. 4 is a block diagram showing the configuration of the limiter circuit 94.

  In a generator model in which an actual synchronous generator is simply modeled, the difference (load angle δ) between the phase (phase angle) in the generator model and the phase (phase angle) in the generator model is the same as in the actual synchronous generator. ) Exceeds π / 2, it will step out. Examples of the case where the load angle δ increases as described above include a case where an unexpectedly large load is applied and a case where a trouble such as a ground fault or a power failure occurs.

  Therefore, in the present invention, the virtual power generator model unit 13 includes phase angle limiting means for limiting the generator internal phase angle ωe so that the absolute value of the load angle δ in the generator model 30 is equal to or smaller than a predetermined angle. . Various means for limiting the phase angle are conceivable. In the present embodiment, the limiter circuit 93 is configured as follows.

  As shown in FIG. 4, the limiter circuit 93 includes an interphase voltage calculation circuit 98, a PLL 99, and a limiter 97. The output voltage va, vb, vc detected by the voltage sensor 6 is input to the interphase voltage calculation circuit 98. Since the output line provided with the voltage sensor 6 is connected to the distribution line 9 of the microgrid via the transformer 8, the output voltage va, vb, vc corresponds to the system voltage. The interphase voltage calculation circuit 98 calculates the interphase voltage from the output voltages va, vb, and vc. The PLL 99 estimates the phase (phase angle) θs of the system voltage (output voltage) from the phase voltage calculated by the phase voltage calculation circuit 98. The limiter 97 limits the generator internal phase angle θm input from the integrator 64 to a range between the upper limit value θs + δmax and the lower limit value θs−δmax. That is, the limiter 97 limits the value of the generator internal phase angle θm with respect to the phase θs of the system voltage at that time so that the generator internal phase angle θm at that time falls within the range of ± δmax. Here, δmax is preset in the limiter 97 as the maximum value of the load angle δ so that the generator model 30 does not step out. The absolute value of the maximum load angle δmax is normally set to π / 2. Theoretically, the step-out occurs when the absolute value of the load angle δ exceeds π / 2. However, the absolute value of the maximum load angle δmax may be set to a predetermined angle smaller than π / 2. For example, it may be determined according to the rated output of the generator model 30. Since the output of the generator model 30 is proportional to the sine of the load angle δ (sin δ), the phase angle limiting means limits the active power within a predetermined limit and functions as a safety device. To do. Further, the limiter 97 may be configured to automatically set the maximum load angle δmax according to the rated output of the generator model by software.

  According to such a configuration, the absolute value of the load angle δ that is the difference angle between the phase θs of the system voltage and the generator internal phase angle θm is less than the absolute value of δmax that is the maximum value of the allowable load angle δ. Therefore, step-out can be prevented. As a result, it is possible to reduce the necessity of tripping the power converter PC to prevent step-out. Since the generator internal phase angle θm is merely a calculation, an arbitrary value can be given. Therefore, even if the generator internal phase angle θm is limited in this way, the function of the virtual power generator model unit 13 is not impaired.

  Next, the switching circuit 94 will be described in detail. FIG. 5 is a block diagram showing the configuration of the switching circuit 94.

  A generator model obtained by simply modeling an actual generator is usually designed to operate stably on the assumption that it is in a steady state (normal operation state). However, in such a generator model, when the internal initial state is 0 or a specific value at the time of startup, an initial current flows according to the system voltage at the time of startup (from the power converter to the initial value). Current is output).

  Therefore, in the present invention, the virtual power generation device model unit 13 performs a predetermined start operation (start sequence) (also a start operation of the power conversion device PC), and when the start operation is completed, normal operation (power generation operation or motor operation) is completed. Configured to migrate to. Although various activation operations can be considered, the present embodiment is configured as follows.

  As shown in FIG. 5, the switching circuit 94 selectively inputs the input voltage command Vref and the input effective voltage Vg to the addition / subtraction circuit 73, and the input effective voltage Vg. And a switch 202 that selectively outputs the generator terminal voltage effective value Vg-VG to the adder / subtractor circuit 73. The generator terminal voltage effective value Vg-VG is calculated based on the output voltages (system voltages) va, vb, vc and the synchronous impedance assumed for the generator model 30 in a predetermined arithmetic circuit (not shown), and is input to the switch 202. Is done. The switching circuit 94 switches the switch 201 so as to output the effective voltage Vg to the adder / subtractor circuit 73 and outputs the generator terminal voltage effective value Vg-VG to the adder / subtracter circuit 73 in the starting operation of the virtual power generator model unit 13. 202 is switched. As a result, the difference between the power generation terminal voltage effective value Vg−VG and the effective voltage Vg is input to the adder / subtractor 73 as a value to be added to the output of the droop 72. In the generator model 30, current command values Id-ref and Iq-ref corresponding to the difference are output to the control signal generation unit 20, and finally a current corresponding to the difference is output from the power conversion unit 3. . Here, the difference between the power generation terminal voltage effective value Vg-VG and the effective voltage Vg is an appropriate value determined by the droop of the reactive power command Qref and the reactive power Qg by the PI control of the AVR. The current output from the power conversion unit 3 according to the difference is not large. Therefore, an excessive initial current is prevented from being output from the power conversion unit 3 at the time of startup. In the present embodiment, since the power generation terminal voltage effective value Vg-VG is used to reduce the value to be added to the output of the droop 72 in the adder / subtractor 73, the difference from the effective voltage Vg is small. A correct voltage value may be input instead of the power generation terminal voltage effective value Vg-VG. Also by this, the current output from the power converter 3 can be suppressed. Moreover, if a value is selected such that the current output from the power conversion unit 3 becomes 0 as the appropriate voltage value, the current (initial current) output from the power conversion unit 3 can be set to 0. However, if the power generation terminal voltage effective value Vg-VG is used, the power generation terminal voltage effective value Vg-VG also varies with the fluctuation of the system voltage during the start-up operation. The current output from the converter 3 can be suppressed.

  Next, a modification of the present embodiment will be described.

[Modification 1]
In this modification, the virtual load is changed corresponding to the actual change of the load 11. Specifically, the current value ΔId-ref (the amount limited by the limiter 95 of the d-axis current command value Id-ref) is changed corresponding to the actual change of the load 11. The change of the load 11 is obtained by detecting the current flowing through the wiring 9 of the microgrid and using the detected current and the output voltage (system voltage) va, vb, vc.

  If comprised in this way, the total load of the generator model 30 can be operated. For example, the charging operation can be performed without causing the generator model 30 to act as an electric motor, and the power generator model unit 13 can be operated and operated intuitively.

[Modification 2]
In this modification, the virtual load is always connected to the generator model 30. Specifically, in place of the limiter circuit 91 of FIGS. 2 and 3, a subtraction circuit that subtracts the current value ΔId-ref corresponding to the virtual load from the d-axis current command value Id-ref used for the calculation of the electric torque Te. Is provided.

  With this configuration, a virtual load is always connected to the generator model 30 in addition to the actual load 11, so even if a voltage drop occurs due to a load drop or the like, Since the load does not drop, it is possible to suppress a voltage increase that is originally determined only by the short-circuit ratio.

[simulation]
Next, a simulation performed to verify the effect in this embodiment will be described.

  In the simulation, a 200 kVA generator having the following Park constant was assumed as a generator represented by the generator model 30.

(Park constant of generator model)
d-axis synchronous reactance: Xd = 2.05
q-axis synchronous reactance: Xq = 1.94
d-axis transient reactance: Xd ′ = 0.22
d-axis next-order transient reactance: Xd "= 0.17
q-axis order transient reactance: Xq "= 0.17
Reverse phase reactance: X2 = 0.17
Zero-phase reactance: X0 = 0.09
Opening time constant: Td0 ′ = 6.3
d-axis transient time constant: Td ′ = 0.7
d-axis transient time constant: Td "= 0.03
Armature time constant: Ta = 0.25
The Park constant is for designating the characteristics of the generator, and the above-mentioned Park constant is described in, for example, the document “Shinji Moriyasu: Practical Electrical Equipment, Morikita Publishing (2000)”.

  In the simulation, the grid (microgrid distribution line 9) includes a power storage device PS, a 350 kW gas engine generator 10 (hereinafter abbreviated as “generator 10”), a load, as shown in FIG. 11 is connected, and the microgrid is operated in an independent form. In the governor model 80, the input of the switching circuit 84 can be switched by the user. In the following, it is assumed that the input of the switching circuit 84 is connected to the first-order lag calculation block 83. A configuration in which the angular velocity command value ωref is not input, the switching circuit 84 is not provided, and the output of the first-order lag calculation block 83 is directly input to the adder / subtractor 85 is also possible.

  First, a simulation result when a step load is applied to the system is shown in FIG. FIG. 6A shows a response waveform of active power with respect to a step load, and FIG. 6B shows a response waveform of system frequency with respect to the step load.

  In FIG. 6 (a), the active power consumed by the load when the step load is applied to the system (microgrid distribution line 9) from 1 second to 7 seconds on the basis of a certain time, The active power to be output and the change with time of the active power output from the power converter PC are shown. First, from the steady state in which the generator 10 supplies all of the active power 100 kW consumed by the load 11, a step load is applied at 1 second, and when the active power of the load increases, the increase is shared. Thus, the active power output from the power converter PC increases as the active power of the generator 10 increases. Thereafter, the active power of the generator 10 gradually increases and the active power of the power conversion device PC gradually decreases. When the step load disappears at 7 seconds and the active power of the load returns to 100 kW, the active power of the generator 10 and Both the effective power of the power converter PC decreases. Thereafter, the active power of the generator 10 gradually decreases so as to converge to 100 kW, and the effective power of the power converter PC gradually increases so as to converge from a negative value to 0 kW. Here, the negative value of the active power of the power conversion device PC means that the virtual power generation device assumed in the virtual power generation device model unit 13 is in the operation area as an electric motor. In this case, the power conversion unit 3 operates as a rectifier, and the secondary battery 1 is charged with electric power.

  Next, in FIG. 6B, when the droop of the governor model 80 (the droop set value of the droop block 82) is set to 3%, when it is set to 5%, and there is no power storage device PS. Each case is simulated, and the change over time in the system frequency (frequency of the distribution line 9 of the microgrid) when a step load is applied between 1 second and 7 seconds with respect to a certain time is shown. From FIG. 6B, when there is no power storage device PS, the fluctuation of the system frequency is large, but when the power storage device PS is present (droop is 3%, 5%), the fluctuation of the system frequency is suppressed. You can see that it is made. Furthermore, it can be seen that fluctuations in the system frequency can be suppressed more when the set value of the droop of the governor model 80 is 3% than when the droop setting value is 5%. Since the fluctuation of the system frequency is preferably within ± 0.2 Hz with respect to the reference frequency (50 Hz), in this embodiment, the droop of the governor model 80 may be set to 3%. In the simulation here, the droop of the AVR model 70 (the droop setting value of the droop block 72) is a constant value of 5%, for example.

  Next, FIG. 4 shows a simulation result when a harmonic load is present. FIG. 4 shows waveforms of the output current, the load current, and the output current of the power generator 10 when a harmonic load is present, and all show the a-phase current waveform. Note that the b-phase and c-phase current waveforms are the same except that the phases are different, and are not shown. As shown in FIG. 7, harmonic components are included in the output of the power converter PC, and the harmonic components of the load current can be shared between the output of the generator 10 and the output of the power converter PC. I understand.

  Next, a simulation result when an unbalanced load exists is shown in FIG. Fig.8 (a) shows the waveform of the load current when an unbalanced load exists, and FIG.8 (b) shows the waveform of the output current of power converter device PC in the same case. 8A and 8B, an unbalanced current can be output from the power conversion apparatus PC to the unbalanced load. Therefore, it can be seen that the unbalanced portion of the load current can be shared by the output of the generator 10 and the output of the power conversion device PC.

  From the above simulation results, when the microgrid is operated in an independent form, even if the load current includes a harmonic component or a three-phase unbalanced state occurs, the power conversion device PC is connected to the gas engine generator 10 or the like. Since harmonic currents and unbalanced currents are output in the same way as ordinary power generators, harmonic components and unbalanced components can be borne with normal power generators, and the burden on the power generators can be reduced. . In this way, it is possible to stabilize the power quality of the own system in cooperation with a normal power generator. In the present embodiment, detection means for the voltage sensor 2, the current sensor 4, and the voltage sensor 6 are necessary, but such detection means is provided as an internal component of the power conversion device PC. There is no need to provide a separate load current or power detection means connected to the distribution line 9.

  In addition to the case where the microgrid is operated in an independent form as described above, there is a case where the microgrid is operated in an interconnected form connected to a commercial power system. In the case of this interconnection form, the microgrid distribution line 9 is connected to the distribution line 16 of the commercial power system via the circuit breaker 15. Here, the normal state in which the circuit breaker 15 is closed (hereinafter referred to as “connected state”), an abnormality or the like occurs in the commercial power system, and the circuit breaker 15 is opened and disconnected from the commercial power system. There is a state (hereinafter referred to as “interconnection interruption state”). In the power conversion device PC of the present embodiment, since the control unit 12 includes the virtual power generation device model unit 13, it is possible to perform frequency control and voltage control similar to those of an actual power generation device, and in an interconnected connection state. In both cases, the operation of the power conversion device PC is the same as in the case where the power conversion device PC is operated in an independent form, and it is possible to stabilize the power quality of the own system in cooperation with a normal power generation device. It becomes possible. Further, even when shifting from the connected state to the disconnected state, it is possible to stabilize the power quality of the own system in a transient manner in cooperation with a normal power generator.

  As described above, in the power conversion device PC according to the present embodiment, when the microgrid is operated in the interconnected form, the same control method is used in the interconnected connection state and in the interconnected disconnection state. There is no need to switch the control method as in the power converter used in the storage device. Further, it is not necessary to detect the state of the system in order to switch the control method.

  In addition, when the microgrid is operated in an independent form, or when the connection is cut off in the operation in the connected form, the operation of the normal power generator in the microgrid is stopped, and the power storage device PS is used alone. Even in the case of operating with the power storage device PS, it is possible to operate alone without switching the control method.

  In addition, the control device 14 that manages and manages the microgrid can handle the power storage device PS in the same manner as a normal power generation device, and the control by the microgrid control device 14 becomes easy. In addition, for the user, the power storage device PS can be handled in the same manner as a normal power generation device, and its behavior can be predicted and adjustment is easy. In this case, for example, the droop setting value of the AVR model 70, the droop setting value of the governor model 80, the unit inertia constant of the engine model 60, and the like can be adjusted by the user. Further, the voltage command value Vref of the AVR model 70 and the angular velocity command value ωref of the governor model 80 are input from the microgrid control device 14, but the voltage command value Vref and the angular velocity command value ωref are adjusted by the user. It is good also as a possible structure. Here, for the adjustment of the angular velocity command value ωref by the user, the input of the switching circuit 84 may be switched to the angular velocity command value ωref, and a desired value may be input as the angular velocity command value ωref. For example, when the microgrid is operated in an independent form, the voltage command value Vref and the angular velocity command value ωref can be set to desired values, and the output voltage and the frequency can be kept constant.

  Further, since the power generation device assumed in the virtual power generation device model unit 13 of the power conversion device PC is a virtual power generation device, the controllable range with respect to frequency and voltage can be made wider than the actual power generation device.

  Further, since the power generation device assumed in the virtual power generation device model unit 13 of the power conversion device PC is a virtual power generation device, it is possible to control to output negative power, that is, to operate as an electric motor. Since the input electric power is charged in the secondary battery 1, there is no loss.

Further, the generator parameters (Park constant) simulated by the generator model 30 of the virtual generator model unit 13 can be arbitrarily changed. At this time, even a value that cannot be set due to problems such as physical constraints and efficiency in an actual generator can be set in the generator model 30 and a generator that does not actually exist can be simulated. .


Furthermore, the response speed of the virtual power generation device model unit 13 is increased, and the model order is decreased, which facilitates adjustment.

  In addition, it is possible to prevent the occurrence of problems due to the armature reaction in the generator model.

  Moreover, it is possible to prevent an excessive current from being output from the power conversion unit during the startup operation of the virtual power generation device model unit.

  Further, step-out can be prevented.

  The power conversion device according to the present invention is useful as a power conversion device used in a power storage device of a power supply system using a distributed power source such as a microgrid.

It is a circuit diagram which shows the structural example of the microgrid using the power converter device of embodiment of this invention. It is a block diagram which shows the detailed structure of the control part of the power converter device of embodiment of this invention. It is a block diagram which shows the structure of the limiter circuit which restrict | limits a generator internal phase angle so that a load angle may be in a predetermined | prescribed limit. It is a block diagram which shows the structure of the switching circuit which switches and outputs the input voltage command, the effective voltage, and the generator terminal voltage effective value. It is a block diagram which shows the detailed structure of the control part of the power converter device of embodiment of this invention. (A) is the response waveform figure of the active power with respect to the step load by simulation, (b) is the response waveform figure of the system frequency with respect to the same step load by simulation. It is a wave form diagram of the output current of a power converter device, load current, and the output current of a gas engine generator in case the harmonic load by simulation exists. (A) is a waveform diagram of a load current when an unbalanced load is present by simulation, and (b) is a waveform diagram of an output current of the power conversion device when an unbalanced load is present by the simulation. . It is a graph which shows the simulation result of the virtual electric power generating apparatus model in which an engine model contains the response characteristic of an engine.

Explanation of symbols

PS power storage device PC power conversion device 1 secondary battery 2 voltage sensor 3 power conversion unit 4 current sensor 5 output reactor 6 voltage sensor 7 filter capacitor 8 transformer 9 microgrid distribution line 10 gas engine generator 11 load 12 control unit 13 Virtual generator model part 14 Micro grid controller 15 Breaker 16 Distribution line 20 of commercial power system Control signal generator 30 Generator model 60 Engine model 70 AVR model 80 Governor model 91 Limiter circuits 92, 96 Addition / subtraction circuit 93 Limiter circuit 94 switching circuit 95, 97 limiter 98 phase voltage calculation circuit 99 PLL
201, 202 switch

Claims (6)

Converting the DC power of the secondary battery into AC power, outputting to an output line connected to the AC circuit, and converting AC power input from the AC circuit through the output line into DC power, A power converter that can be stored in a secondary battery;
A control unit for controlling the power conversion unit,
The controller is
When it is assumed that a virtual power generation device that is an imaginary power generation device is provided in advance instead of the power conversion unit and the secondary battery, and an output line of the power conversion unit is an output line of the virtual power generation device And calculating a current value to be output by the virtual power generation device based on the voltage of the output line of the power conversion unit, and setting the calculated current value as a current command value to the current command value. A power conversion control unit that controls the power conversion unit by current feedback control so as to output a corresponding current to the output line;
The virtual power generator model unit controls the generator, the AVR that controls the field voltage of the generator, the prime mover that drives the generator, and the fuel supply amount to the prime mover. In the case where it is assumed that it is configured to include a governor, the generator, the AVR, the prime mover, and the governor have a generator model, AVR model, prime mover model, and governor model that define input / output relationships of the governor,
The AVR model is configured to calculate the field voltage of the generator based on the voltage of the output line of the power converter, the reactive power command value given from the outside, and the voltage command value of the output line. ,
The governor model is based on an angular velocity of the generator calculated in the prime mover model, an active power command value given from the outside, and at least the active power command value of the angular velocity command value of the generator. Configured to calculate the fuel supply to the prime mover,
The prime mover model calculates an angular velocity and a phase angle of the generator based on the fuel supply amount calculated by the governor model and an electric torque of the generator calculated by the generator model. Composed of
The generator model includes the voltage of the output line of the power converter, the field voltage of the generator calculated by the AVR model, and the angular velocity and phase angle of the generator calculated by the prime mover model. Based on the above, the electric torque of the generator, which is a mechanical load of the prime mover, and the straight axis current value and the horizontal axis current value output by the generator are calculated, and the calculated straight axis current value and horizontal axis current are calculated. A value is set to the current command value,
The prime mover model converts the fuel supply amount calculated by the governor model into a mechanical torque of the prime mover without considering the response characteristic of the prime mover, and uses the angular velocity and phase angle of the generator. A power conversion device configured to calculate   The virtual power generation device model section has a reactance that cancels a reactance component of the load in parallel with the load on the AC circuit in the generator model when the power factor of the load on the AC circuit is lower than a predetermined value. The power conversion device according to claim 1, wherein the power conversion device is configured to behave as if a load is connected.   The virtual power generation device model unit is configured to have a startup operation and a normal operation after the startup operation is completed, and the AVR model is configured such that the voltage of the output line and the output in the startup operation of the power converter A field voltage of the generator is calculated using a predetermined voltage instead of at least one of the voltage command values of the line, and the voltage of the output line of the power conversion unit and the output in normal operation of the power conversion unit The power conversion device according to claim 1, configured to calculate a field voltage of the generator based on a voltage command value of a line.   The power converter according to claim 3, wherein the predetermined voltage is a terminal voltage of the generator calculated based on a voltage of an output line of the power converter.   The virtual power generator includes phase angle limiting means for limiting the phase angle of the generator so that the absolute value of the difference angle between the phase angle of the voltage of the output line and the phase angle of the generator is a predetermined angle or less. The power conversion device according to claim 1, wherein the power conversion device is configured to have the power conversion device.   The virtual power generator model unit calculates a direct axis current value and a horizontal axis current value as current values to be output by the virtual power generator, and determines the calculated direct axis current value and horizontal axis current value as the current command value. The power conversion device according to claim 1.

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