JP2019080476A - Ac-dc converter control device - Google Patents

Abstract

To provide an AC-DC converter control device capable of simplifying the control circuit of an AC-DC converter, while restraining frequency change equally to synchronous generator.SOLUTION: A generator characteristic arithmetic section 19 for calculating the generator characteristics of a virtual synchronous generator has a rotor angular speed arithmetic part 21 for obtaining the rotor angular speed of the virtual synchronous generator on the basis of the torque command value and the output torque of the virtual synchronous generator and the inertia constant and the brake factor of the virtual synchronous generator, and a voltage command value arithmetic part 20 for calculating the voltage command value of an AC-DC converter so that the output power from an AC-DC converter 17 becomes the output command value of the virtual synchronous generator, on the basis of the internal induction voltage of the virtual synchronous generator calculated on the basis of the rotor angular speed and the internal impedance of the virtual synchronous generator, and an output current suppression part 32 changes the internal impedance of the virtual synchronous generator, so that the output current from the AC-DC converter does not exceed a current limit value when short circuit incident occurs in a power system.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an AC-DC converter control device that controls an AC-DC converter that charges and discharges the power of a storage battery to an electric power system in which a synchronous generator and a storage battery are linked.

  The power system was previously constituted by a power generation system by a synchronous generator, but in recent years, instead of the power generation system by a synchronous generator, renewable energy power sources such as solar power generation facilities are increasing. For example, since the photovoltaic power generation equipment, which is a renewable energy power supply, is operated to supply generated power to the power system regardless of the demand of the power system, a storage battery is connected to the power system, and surplus power system The battery is operated to charge the storage battery from the power system when power is available, and to discharge the storage battery to the power system when the demand of the power system is large. When the number of solar power generation facilities in the power system increases, the number of synchronous generators connected to the power system relatively decreases.

  In such an electric power system, when the frequency of the electric power system fluctuates due to the increase and decrease of the load of the electric power system, the synchronous generator connected to the same system bears the increase and decrease of the load. The synchronous generator potentially has the function of suppressing the frequency fluctuation of the electric power system, and since the governor is equipped, the amount of power generation can be reduced so as to suppress the frequency fluctuation. The adjustment contributes to the stabilization of the frequency. On the other hand, since the solar power generation facility outputs constant electric power regardless of the load fluctuation of the electric power system when the amount of solar radiation is constant, if the synchronous generator of the electric power system is small, the inertia force that the synchronous electric generator had at the time of sudden load change Is lost and the change in frequency at the time of sudden load change becomes large.

  Therefore, the control of the storage battery is simulated to have a synchronization force or an inertial force so that the output characteristics of the storage battery have the same characteristics as those of a synchronous generator linked to the electric power system, and the frequency of the same as that of the synchronous generator. There is a device (hereinafter, referred to as a virtual synchronous generator) in which the fluctuation is suppressed (see, for example, Patent Document 1).

JP, 2013-162623, A

  However, according to Patent Document 1, the power conversion control unit of the power conversion device that controls the storage battery is a virtual synchronous power generation that includes the frequency fluctuation suppression power generation output from the generator characteristic calculation unit that models the synchronous generator. Since the storage battery is controlled so that the output current value IGref of the generator is supplied and the output current supplied from the storage battery to the power system becomes the output current value IGref of the virtual synchronous generator, the storage battery power converter is equivalent to In order to exhibit the behavior as a current source, for example, when a capacitor is connected to an AC circuit to suppress overvoltage even when the system impedance increases, it is necessary to perform current control at high speed to approximate a voltage waveform to a sine wave. .

  The object of the present invention is to make it possible to achieve isolated operation by artificially having inertia force and synchronization force as control characteristics like a synchronous generator, and easily performing parallel and parallel connection with the power system, and An AC / DC converter having an AC / DC converter control device capable of continuing operation without protection and stop due to an overcurrent even if a short circuit accident occurs in the system.

  An AC / DC converter control device according to the invention of claim 1 controls an AC / DC converter for charging and discharging electric power of the storage battery in an electric power system in which a synchronous generator and a storage battery are connected. A generator characteristic calculation unit for calculating the synchronous generator characteristic such that the electric power output from the unit has the same characteristic as the characteristic of the synchronous generator, and a short circuit accident in the electric power system; And an output current suppression unit that changes the internal impedance of the virtual synchronous generator so that the output current does not exceed the current limit value, and the generator characteristic calculation unit calculates a torque command value and an output torque of the virtual synchronous generator. A rotor angular velocity calculation unit for calculating a rotor angular velocity of the virtual synchronous generator based on an inertia constant and a braking coefficient of the virtual synchronous generator; and a rotor angle obtained by the rotor angular velocity calculation unit Calculate the internal induced voltage of the virtual synchronous generator based on the degree, and the output power of the AC / DC converter becomes the output command value of the virtual synchronous generator based on the internal induced voltage and the internal impedance of the virtual synchronous generator And a voltage command value calculating unit for calculating a voltage command value of the AC / DC converter.

  The AC / DC converter control device according to the invention of claim 2 is characterized in that, in the invention of claim 1, the current limit value is equal to or less than an allowable current value of the virtual synchronous generator.

  The AC / DC converter control device according to the invention of claim 3 is characterized in that, in the invention of claim 1, the current limit value is a current value capable of eliminating an arc at a short circuit accident occurrence point of the power system.

  In the AC / DC converter control device according to the invention of claim 4, according to the invention of any one of claims 1 to 3, according to the number of synchronous generators interconnected to the electric power system, It is characterized in that the inertia constant and the braking coefficient are changed.

  The AC / DC converter control device according to the invention of claim 5 is the invention according to any one of claims 1 to 4, wherein a phase of the internal induced voltage of the virtual synchronous generator is a phase of a system voltage of the power system. A synchronization verification unit is provided to synchronize.

  According to the invention of claim 1, the synchronous generator characteristic of the virtual synchronous generator is calculated so that the power output from the storage battery has a characteristic equivalent to the characteristic of the synchronous generator, and the output power of the AC / DC converter of the storage battery Has a circuit configuration that outputs the voltage command value of the AC / DC converter of the storage battery so as to have characteristics as a voltage source as the output command value of the virtual synchronous generator, and the output current of the AC / DC converter does not exceed the current limit value. Vary the internal impedance of the virtual synchronous generator. Therefore, even if a short circuit accident occurs in the power system, it can be prevented that the current output from the storage battery to the power system becomes equal to or more than the current limit value. Further, since the internal impedance of the virtual synchronous generator is changed, the control circuit of the AC / DC converter that controls the storage battery can be simplified even if the generator characteristic calculation unit modeled the synchronous generator is used, When the load of the electric power system changes suddenly, the AC / DC converter of the storage battery can be controlled to suppress the frequency change equivalent to that of the synchronous generator.

  According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the current limit value is equal to or less than the allowable current value of the virtual synchronous generator, the short circuit current is assumed even if a short circuit accident occurs in the power system. It can be suppressed below the allowable current value of the synchronous generator.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1, the current limit value is a current value capable of extinguishing the arc at the short circuit accident occurrence point of the power system. It is possible to extinguish an arc and eliminate a short circuit accident.

  According to the invention of claim 4, in addition to the effect of the invention according to any one of claims 1 to 3, according to the number of synchronous generators interconnected to the electric power system, inertia constant and braking coefficient of the rotor angular velocity calculation unit Because the inertia force of the virtual synchronous generator can be secured even if the number of synchronous generators connected to the power system decreases with the increase of renewable energy power sources, the frequency change at the time of a sudden change in load can be obtained. It can be suppressed.

  According to the invention of claim 5, in addition to the effect of the invention according to any one of claims 1 to 4, a synchronization test unit which synchronizes the phase of the internal induced voltage of the virtual synchronous generator with the phase of the grid voltage of the power system. In the case of connecting the virtual synchronous generator to the electric power system, the synchronous detector becomes unnecessary, and the phase locked circuit PLL (phase locked loop) also becomes unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the AC / DC converter control apparatus which concerns on 1st Embodiment of this invention. Operation explanatory drawing which shows an example of operation | movement of the output current suppression part in 1st Embodiment of this invention The wave form diagram which shows an example of the output current of an AC / DC converter when a two-phase short circuit accident generate | occur | produces in electric power system. The wave form diagram which shows an example of the output current of an AC / DC converter when a 3-phase short circuit accident generate | occur | produces in an electric power grid | system. The block diagram of the AC / DC converter control apparatus which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a block diagram of an AC / DC converter control device 11 according to a first embodiment of the present invention. FIG. 1 shows that the AC / DC converter storage battery system 14 is connected to the power system 12 via the circuit breaker 13, and the AC / DC converter storage battery system 14 charges and discharges the power of the storage battery 15 via the reactor 16. And an AC / DC converter 17. In addition, illustration of renewable energy power supplies, such as a solar power generation facility, is abbreviate | omitted.

  The AC / DC converter 17 of the AC / DC converter battery system 14 is controlled by the AC / DC converter controller 11 according to the first embodiment of the present invention. The AC / DC converter control device 11 is composed of a control computing unit 18 and a generator characteristic computing unit 19, and the generator characteristic computing unit 19 is composed of a voltage command value computing unit 20 and a rotor angular velocity computing unit 21. .

  The control operation unit 18 performs PWM control of the voltage command value Vm (= va, vb, vc) calculated by the voltage command value calculation unit 20 of the generator characteristic calculation unit 19 by the PWM control unit 22 and controls the gate pulse generation unit 23. The output power from the storage battery 15 is controlled so that the power output from the storage battery 15 becomes the output power of the virtual synchronous generator calculated by the generator characteristic calculation unit 19 via the output to the AC / DC converter 17. The generator characteristic calculation unit 19 calculates the generator characteristic of the virtual synchronous generator so that the power output from the storage battery 15 has the same characteristic as the characteristic of the synchronous generator. By controlling the converter 17, the storage battery 15 can output the output power having the same characteristic as that of the synchronous generator, so that the frequency maintenance effect by the inertia force of the synchronous generator can be enhanced against the frequency fluctuation of the power system. There is.

  The rotor angular velocity calculation unit 21 of the generator characteristic calculation unit 19 obtains the rotor angular velocity ω of the virtual synchronous generator. The output command value (output target value) Pm of the virtual synchronous generator is input to the proportional unit 24a, multiplied by 1 / ω to calculate a torque command value (torque target value) Tm, and input to the adder 25a. The output torque Te of the virtual synchronous generator, the braking torque Td, and the governor torque Tg are also input to the adder 25a, and a torque deviation ΔT (= Tm-Te-Td-Tg) is calculated. The torque deviation ΔT is input to the proportional unit 24b, multiplied by 1 / M to calculate the angular acceleration deviation ΔT / M, and input to the integrator 26a. M is the inertia constant of the rotor of the virtual synchronous generator. The angular acceleration deviation ΔT / M is integrated by the integrator 26 a to obtain the angular velocity deviation Δω.

  The angular velocity deviation .DELTA..omega. Is multiplied by the braking coefficient D by the proportional unit 24c to become the braking torque Td and negatively fed back to the adder 25a. Similarly, the angular velocity deviation .DELTA..omega. Is multiplied by the control coefficient K by the proportional unit 24d to become the control torque Tg and negatively fed back to the adder 25a. Further, the angular velocity deviation Δω is input to the adder 25 b and added to the angular velocity reference value ω 0 to become the rotor angular velocity ω of the virtual synchronous generator. Here, the output torque Te is obtained by dividing the output power Pe of the virtual synchronous generator by the rotor angular velocity ω by the divider 27 of the voltage command value calculation unit 19, and is negatively fed back to the adder 25a.

  As described above, the rotor angular velocity calculation unit 21 calculates the output torque Te corresponding to the output power Pe of the virtual synchronous generator, the torque command value Tm corresponding to the output command value Pm, and the inertia constant M of the virtual synchronous generator and braking. The rotor angular velocity ω of the virtual synchronous generator is determined based on the coefficient D.

  The voltage command value calculator 20 of the generator characteristic calculator 19 calculates the voltage command value Vm to the AC / DC converter 17. Since voltage command value Vm is three phases, it is expressed as Vm (= va, vb, vc). As described above, voltage command values Vm (= va, vb, vc) are output to AC / DC converter 17 through PWM control unit 22 and gate pulse generation unit 23 of control operation unit 18.

  The rotor angular velocity ω obtained by the rotor angular velocity calculation unit 21 is input to the integrator 26 b of the voltage command value calculation unit 20 and integrated by the integrator 26 b to obtain the rotor phase θ. The rotor phase θ is input to the sine wave generator 28, and the sine wave generator 28 calculates a three-phase sine wave {sin θ, sin (θ-2π / 3), sin (θ + 2π / 3)} and the multiplier 29a Is input to

  On the other hand, the system voltage V1 detected by the voltage detector 30 is input to the adder 25c of the generator characteristic calculation unit 19, and the adder 25c calculates the difference between the voltage reference value Vr and the system voltage V1 to calculate the voltage regulator 31. Is input to Voltage regulator 31 calculates peak value Ei of 3-phase sine wave {sin θ, sin (θ−2π / 3), sin (θ + 2π / 3)} so that system voltage V1 becomes voltage reference value Vr, and multiplication Output to the output unit 29a.

  The multiplier 29a multiplies the peak value Ei by the three-phase sine wave {sin θ, sin (θ-2π / 3), sin (θ + 2π / 3)} to calculate the internal induced voltage ei of the virtual synchronous generator. . The internal induced voltage ei is expressed as ei = {Ei · sin θ, Ei · sin (θ−2π / 3), Ei · sin (θ + 2π / 3)} as a three-phase sine wave. The internal induced voltage ei of the virtual synchronous generator is input to the multiplier 29b and the adder 25d.

  The output current I1 of the AC / DC converter 17 of the AC / DC converter battery system 14 detected by the current detector 31 is also input to the multiplier 29b, and the multiplier 29b receives the internal induced voltage ei of the virtual synchronous generator and the AC / DC converter 17. Output current I1 of the virtual synchronous generator output from the AC / DC converter battery system 14 to the electric power system 12 is calculated. As described above, the output power Pe of the virtual synchronous generator is divided by the rotor angular velocity ω by the divider 27 to obtain the output torque Te (= Pe / ω), and to the adder 25 a of the rotor angular velocity calculation unit 21 Negative feedback.

  On the other hand, in addition to the internal induced voltage ei of the virtual synchronous generator, the voltage VR of the resistance R of the internal impedance Z of the virtual synchronous generator is input to the adder 25d from the proportional unit 24e and the virtual from the proportional unit 24f. The voltage VL of the reactance L of the internal impedance Z of the synchronous generator is input. Thus, voltage command values Vm (= va, vb, vc) of the AC-DC converter 17 maintaining the grid voltage V1 and the output command value Pm of the virtual synchronous generator are calculated.

  Thus, in the AC / DC converter control device 11 according to the first embodiment of the present invention, the output current I1 of the AC / DC converter 17 is detected, and the voltage command value Vm (= va, vb, vc) of the AC / DC converter 17 is detected. The AC / DC converter 17 is operated as a voltage source. In this case, when a short circuit accident occurs in the power system 12, an overcurrent is supplied from the AC / DC converter 17 to the power system 12. Therefore, in the AC / DC converter control device 11 according to the first embodiment of the present invention, an output current suppression unit 32 is provided in order to have a current limiting function with respect to an overcurrent at the time of a short circuit accident of the power system 12. When the output current I1 of the AC-DC converter 17 detected by the current detector 31 exceeds the current threshold, the output current suppression unit 32 prevents the output current I1 of the AC-DC converter 17 from exceeding the current limit value IL. The internal impedance Z of the virtual synchronous generator is changed to increase.

  FIG. 2 is an operation explanatory view showing an example of the operation of the output current suppression unit 32, and FIG. 2 (a) is a diagram showing the relationship between the output current I1 of the AC / DC converter 17 and the internal impedance Z, and FIG. It is a wave form diagram when output current I1 of converter 17 exceeds a current threshold. In FIG. 2A, the current threshold of the output current I1 of the AC / DC converter 17 has the first threshold | I1a | and the second threshold | I1b |, and the first threshold | I1a | and the second threshold | I1b | The relationship with is | I1a |> | I1b |. Now, when the output current I1 of the AC / DC converter 17 is in the range of the first threshold value | I1a | (−I1a <I1 <I1a), the internal impedance Z remains unchanged at Z1.

  On the other hand, when the output current I1 of the AC / DC converter 17 deviates from the range of the first threshold value | I1a | (−I1a <I1 <I1a), the internal impedance Z is changed from Z1 to Z2 to increase the internal impedance Z . Further, the internal impedance Z is restored by changing the internal impedance Z from Z2 to Z1 when the output current I1 of the AC / DC converter 17 returns to the range of the second threshold | I1b | (−I1b <I1 <I1b) Back to.

  In FIG. 2B, since the output current I1 of the AC / DC converter 17 deviates in the minus region of the range of the first threshold value | I1a | (−I1a <I1 <I1a) at time t1, the internal impedance Z is Z2 Then, at time t2, the internal impedance Z returns to Z1 because it returns in the minus region of the range of the second threshold | I1b | (−I1b <I1 <I1b). Then, at time t3, the output current I1 of the AC / DC converter 17 deviates in the plus region of the range of the first threshold value | I1a | (−I1a <I1 <I1a), so the internal impedance Z becomes Z2, and the second impedance at time t4. The internal impedance Z returns to Z1 because it returns in the plus region of the range of the threshold value | I1b | (−I1b <I1 <I1b). Likewise, the internal impedance Z becomes Z2 at time t5, the internal impedance Z returns to Z1 at time t6, the internal impedance Z becomes Z2 at time t7, and the internal impedance Z returns to Z1 at time t8. This operation is repeated as long as the output current I1 of the unit 17 exceeds the first threshold | I1a |.

  In the range in which the internal impedance Z is Z2, the output current I1 of the AC / DC converter 17 is suppressed. Thus, the output current I1 of the AC / DC converter 17 is prevented from exceeding the current limit value IL. FIG. 3 is a waveform diagram showing an example of the output current I1 of the AC-DC converter 17 when a two-phase short circuit accident occurs in the power system 12, and FIG. 3 (a) is a case where the output current suppression unit 32 is not operated. FIG. 3B is a waveform diagram showing an example of the output current I1 of the AC / DC converter 17 when the output current suppression unit 32 is operated. As shown in FIG. 3A, the output current I1 of the AC-DC converter 17 when the output current suppression unit 32 is not operated is two-phase shorted when the two-phase short circuit occurs in the power system 12 A large current flows in the output current I1, but the output current I1 of the AC-DC converter 17 when the output current suppression unit 32 is operated is suppressed to the current limit value IL or less as shown in FIG. 3 (b).

  FIG. 4 is a waveform diagram showing an example of the output current I1 of the AC-DC converter 17 when a three-phase short circuit accident occurs in the power system 12. FIG. 4A shows the case where the output current suppression unit 32 is not operated. 4 (b) is a waveform diagram showing an example of the output current I1 of the AC / DC converter 17 when the output current suppression unit 32 is operated. As shown in FIG. 4A, the output current I1 of the AC-DC converter 17 when the output current suppression unit 32 is not operated is a large current for all three phases when a three-phase short circuit occurs in the power system 12 Although flowing, the output current I1 of the AC / DC converter 17 when the output current suppression unit 32 is operated is suppressed to the current limit value IL or less as shown in FIG. 4 (b).

  Here, the current limit value IL is, for example, an allowable current value of the virtual synchronous generator. Thereby, even if a short circuit accident occurs in the power system 12, the short circuit current can be suppressed to the allowable current value or less of the virtual synchronous generator. Z2 in which the internal impedance Z is increased is determined so that the output current I1 of the AC / DC converter 17 does not exceed the allowable current value of the virtual synchronous generator, which is the current limit value IL. Also, the current limit value IL is, for example, a current value that can extinguish the arc at the short circuit accident occurrence point of the power system 12. As a result, in the case of a short circuit accident that occurs temporarily due to lightning or the like, the arc can be extinguished and the short circuit accident can be eliminated.

  Next, in the AC / DC converter control device 11 according to the first embodiment of the present invention, the inertial force of the virtual synchronous generator is secured in order to be able to suppress the change in frequency when the load of the power system 12 changes suddenly. There is. In order to secure the inertia force of the virtual synchronous generator, the inertia constant M of the proportional unit 24 b of the rotor angular velocity calculation unit 21 and the braking coefficient D of the proportional unit 24 c can be varied, and are interconnected with the power system 12 In accordance with the number of synchronous generators, the inertia constant M of the proportional unit 24b of the rotor angular velocity calculation unit 21 and the braking coefficient D of the proportional unit 24c are set to appropriate values. Specifically, according to the power generation capacity of the AC / DC converter storage battery system introduced instead of the power generation system by the synchronous generator, the virtual synchronous generator can secure the inertial force, The inertia constant M of the proportional unit 24b and the damping coefficient D of the proportional unit 24c are set to appropriate values. As a result, even when the number of synchronous generators interconnected to the power system 12 is small, the inertial force of the entire power system including the virtual synchronous generator can be secured, and the change in frequency at the time of a sudden load change can be suppressed.

  Next, a second embodiment of the present invention will be described. FIG. 5 is a block diagram of an AC / DC converter control device 11 according to a second embodiment of the present invention. This second embodiment is provided with a synchronization test unit 33 that synchronizes the phase θ of the internal induced voltage ei of the virtual synchronous generator with the phase of the grid voltage V1 of the electric power system 12 with respect to the first embodiment shown in FIG. It is The same elements as those in FIG.

  In FIG. 5, in the second embodiment, a synchronization test unit 33 is additionally provided. The synchronization verification unit 33 synchronizes the phase θ of the output voltage of the virtual synchronous generator with the phase of the grid voltage V1 of the power system 12 when the virtual synchronous generator is linked to the power system 12. In order to link the virtual synchronous generator to the power system 12, it is necessary that the magnitude, frequency and phase of the output voltage of the virtual synchronous generator match the size, frequency and phase of the grid voltage .

  The magnitude of the output voltage of the virtual synchronous generator is the voltage command value Vm of the AC / DC converter 17 output from the adder 25d of the voltage command value computing unit 20, and the magnitude of the voltage command value Vm is the same as the grid voltage V1. It is a voltage value of magnitude. The frequency of the output voltage of the virtual synchronous generator is the rotor angular velocity ω (= 2πf: f is a frequency) output from the adder 25 b of the rotor angular velocity calculation unit 21, and the angular velocity reference value ω 0 (= 2πf 0: f 0 is This is a value obtained by adding the angular velocity deviation to the frequency reference value). Since the angular velocity deviation Δω is very small, the frequency of the output voltage of the virtual synchronous generator is approximately equal to the frequency of the grid voltage V1. On the other hand, although the phase θ of the output voltage of the virtual synchronous generator is obtained by integrating the rotor angular velocity ω, it is not known whether it is the same as the phase of the grid voltage V1.

  Therefore, in the first embodiment, the virtual synchronous generator is synchronized with the power system 12 by matching the phase θ of the output voltage of the virtual synchronous generator with the phase of the grid voltage V1 by the synchronization checker or the phase synchronization circuit PLL. You will be forced to enter.

  On the other hand, in the second embodiment, the synchronization test unit 33 synchronizes the virtual synchronous generator with the power system 12 by matching the phase θ of the output voltage of the virtual synchronous generator with the phase of the system voltage V1. The phase difference detection unit 34 of the synchronization test unit 33 calculates the phase deviation Δθ between the phase of the grid voltage V1 and the phase θ of the output voltage of the virtual synchronous generator, and inputs the phase deviation Δθ to the proportional integrator 36 via the switch 35. The proportional integrator 36 outputs an angular velocity deviation Δω1 corresponding to the phase deviation Δθ to the adder 25e. The adder 25e adds the angular velocity deviation Δω1 to the rotor angular velocity ω output from the adder 25b, and inputs the result to the integrator 26b. Thus, the phase deviation Δθ is adjusted to 0, and the phase θ of the output voltage of the virtual synchronous generator becomes substantially the same as the phase of the system voltage V1.

  The switch 35 is turned on when the circuit breaker 13 is open, and turned off when the circuit breaker 13 is turned on. That is, it turns on when the AC / DC converter 17 of the AC / DC converter storage battery system 14 is not connected to the power system 12, and when the virtual synchronous generator is interconnected with the power system 12 (the AC / DC converter 17 is (When connected to) is off. By providing the synchronization verification unit 33, when the virtual synchronous generator is linked to the power system 12, the synchronization verification device is not necessary, and the AC / DC converter control device 11 becomes unnecessary the phase synchronization circuit PLL.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

11 AC-DC Converter Controller 12 Electric Power System 13 Circuit Breaker 14 AC-DC Converter Storage Battery System 15 Storage Battery 16 Reactor 17 AC-DC Converter 18 Control Operation Unit 19 Generator Characteristic Operation Unit 20 Voltage Command Value Calculation unit 21 ... Rotor angular velocity calculation unit 22 ... PWM control unit 23 ... Gate pulse generation unit 24 ... Proportioner 25 ... Adder 26 ... Integrator 27 ... Divider 28 ... Sine wave generator 29 ... Multiplier 30 ... Voltage detection Unit 31 Current detector 32 Output current suppression unit 33 Synchronization test unit 34 Phase difference detection unit 35 Switch 36 Proportional integrator

Claims (5)

An AC / DC converter control device for controlling an AC / DC converter for charging and discharging electric power of the storage battery in an electric power system in which a synchronous generator and a storage battery are connected,
A generator characteristic calculation unit that calculates the synchronous generator characteristics such that the power output from the storage battery has characteristics equivalent to the characteristics of the synchronous generator, and the AC / DC conversion when a short circuit accident occurs in the power system And an output current suppression unit that changes the internal impedance of the virtual synchronous generator so that the output current of the generator does not exceed the current limit value,
The generator characteristic calculation unit calculates a rotor angular velocity of the virtual synchronous generator based on a torque command value and an output torque of the virtual synchronous generator, and an inertia constant and a braking coefficient of the virtual synchronous generator. Internal induction voltage of the virtual synchronous generator based on the rotor angular velocity obtained by the rotor angular velocity calculation unit, and the AC / DC converter of the AC / DC converter based on the internal induction voltage and the internal impedance of the virtual synchronous generator An AC / DC converter control device comprising: a voltage command value calculation unit that calculates a voltage command value of the AC / DC converter so that an output power becomes an output command value of the virtual synchronous generator.   The AC / DC converter control device according to claim 1, wherein the current limit value is an allowable current value of the virtual synchronous generator.   The AC / DC converter control device according to claim 1, wherein the current limit value is a current value that can extinguish an arc at a short circuit occurrence point of the power system.   The AC / DC conversion according to any one of claims 1 to 3, wherein the inertia constant and the braking coefficient of the rotor angular velocity calculation unit are changed according to the number of generators interconnected to the power system. Controller.   The AC / DC conversion according to any one of claims 1 to 4, further comprising a synchronization test unit that synchronizes the phase of the internal induced voltage of the virtual synchronous generator with the phase of a grid voltage of the power system. Controller.

Images