Power converter and power control device

Abstract

This allows the output and / or input of the equipment to be varied in response to transient frequency fluctuations in the grid, thereby suppressing grid frequency fluctuations. [Solution] A power control device according to one embodiment is a power control device that controls a power converter connected to an AC electrical circuit and also connected to an energy storage means, comprising: an energy storage amount acquisition means for measuring or calculating the amount of energy stored in the energy storage means; a phase calculation means for calculating the phase of various electrical quantities of the electrical circuit; an inertia simulation control signal generation means for generating an inertia simulation control signal for the power converter according to the measured phase; and a command means for switching a plurality of functions stored in the inertia simulation control signal generation means or changing the coefficients of the functions, at least according to the amount of energy stored.

Description

Technical Field

[0001] Embodiments of the present invention relate to a power conversion device and a power control device.

Background Art

[0002] Currently, frequency regulation of the power system is mainly performed by controlling the output of thermal power plants and hydroelectric power plants.

[0003] Transient frequency fluctuations before the output control of thermal power plants and hydroelectric power plants takes effect are suppressed by the inertial response of rotating machines such as synchronous generators. Facilities that utilize renewable energy such as solar power generation and wind power generation have variable outputs due to changes in the natural environment. In order to suppress frequency fluctuations, frequency regulation by charge-discharge control of a battery system is being put into practical use.

[0004] A power conversion device (including a control device) applied to a battery system for frequency regulation measures the frequency of an electric circuit, obtains command values for input and output according to the frequency, and controls the input and output of the power conversion device according to the command values. Further, the power conversion device measures the voltage phase of the electric circuit, obtains a control phase, and controls the input and output according to the command values. When the voltage phase changes due to a change in the frequency of the electric circuit or the like, the reference phase for control follows the voltage phase of the electric circuit, and the control device controls the input and output according to the followed control phase. Therefore, the power conversion device can stably control the input and output according to the command values even when the frequency and voltage phase of the electric circuit change.

[0005] Power converters (including control devices) used in electric vehicle charging systems and the like control devices control the input and output of the power converter according to the amount of stored energy. They do not control the input and output of the power converter according to the frequency of the electrical circuit. The power converter measures the voltage phase of the electrical circuit, determines the control phase, and controls the input and output according to the command value. If the voltage phase changes due to changes in the frequency of the electrical circuit, the control reference phase follows the voltage phase of the electrical circuit to control the output. Therefore, the power converter can stably control the input and output according to the command value even if the frequency or voltage phase of the electrical circuit changes. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6422682 [Patent Document 2] Patent No. 6440974 [Patent Document 3] Patent No. 4680102 [Patent Document 4] Patent No. 6831565 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Power generation equipment using synchronous generators, such as thermal and hydroelectric power plants, and charging / discharging equipment such as batteries, control the output of the prime mover through a governor-free function when the frequency of the power grid changes, thereby suppressing frequency fluctuations. For transient frequency fluctuations and voltage phase fluctuations before the prime mover output changes, the output of the synchronous generator changes due to the inertia of the synchronous generator, suppressing transient frequency fluctuations. In other words, power generation equipment using synchronous generators and charging / discharging equipment such as batteries have a function to suppress frequency fluctuations through inertial response.

[0008] On the other hand, wind power and solar power generation cause fluctuations in output due to variations in wind speed and solar radiation, which in turn causes fluctuations in the output command value and thus the output itself, leading to frequency fluctuations in the power grid. Furthermore, power converters used in wind power, solar power, fuel cell systems, and battery storage systems are static devices and do not possess the inertia that synchronous generators have. In addition, because these power converters control the output and / or input according to the command value, they cannot suppress transient frequency fluctuations.

[0009] As the number of charging and discharging facilities connected to the power grid via power conversion devices such as wind and solar power generation increases, and the proportion of power generation facilities using synchronous generators such as thermal and hydroelectric power plants, and charging and discharging facilities such as batteries (charging and discharging facilities with inertia) decreases, there are concerns that the inertia of the entire power grid will decrease, leading to larger frequency fluctuations in the power grid. Therefore, there is a need for power conversion devices that can suppress transient frequency fluctuations to the same extent as power generation facilities using synchronous generators and charging and discharging facilities such as batteries.

[0010] One proposed method for realizing such a power conversion device is virtual synchronous generator control. This control system incorporates a calculation unit in the power conversion device's control device that simulates the characteristics of a synchronous generator, and controls the output of the power conversion device based on the calculation results to simulate the output of a synchronous generator.

[0011] Virtual synchronous generator control requires complex calculations, which presents the challenge of calculation time delays. Furthermore, since the output of power converters behaves differently depending on the functions and constants used in the calculations, if multiple power converters are connected to the same system, the control of each power converter may interfere with each other, potentially adversely affecting the power system.

[0012] The problem that the present invention aims to solve is to provide a power converter and a power control device that can change the output and / or input of the equipment in response to transient frequency fluctuations and voltage phase fluctuations of the grid, thereby suppressing frequency fluctuations of the grid. [Means for solving the problem]

[0013] A power control device in one embodiment controls a power converter connected to an AC electrical circuit and also connected to an energy storage means, and comprises: an energy storage amount acquisition means for measuring or calculating the amount of energy stored in the energy storage means; a phase calculation means for calculating the phase of various electrical quantities of the electrical circuit; an inertia simulation control signal generation means for generating an inertia simulation control signal for the power converter according to the measured phase; and a command means for switching between a plurality of functions stored in the inertia simulation control signal generation means or changing the coefficients of the functions, at least according to the amount of energy stored. [Effects of the Invention]

[0014] According to the present invention, it becomes possible to change the output and / or input of the equipment in response to transient frequency fluctuations in the power system, thereby suppressing frequency fluctuations in the power system. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a conceptual diagram showing an example of the configuration of a charging facility having a power converter according to the first embodiment (when the grid frequency is stable). [Figure 2] Figure 2 is a conceptual diagram showing an example of the configuration of a charging facility having a power converter according to the first embodiment (situation when the grid frequency decreases). [Figure 3] Figure 3 is a conceptual diagram showing an example of the configuration of a charging facility having a power converter according to the first embodiment (situation when the grid frequency increases). [Figure 4] Figure 4 is a simplified conceptual diagram showing an example of the configuration of a charging facility with a conventional power conversion device (when the grid frequency is stable). [Figure 5] Figure 5 is a simplified conceptual diagram showing an example of the configuration of a charging facility with a conventional power conversion device (situation when the grid frequency decreases). [Figure 6] Figure 6 is a simplified conceptual diagram showing an example of the configuration of a charging facility with a conventional power conversion device (situation when the grid frequency increases). [Figure 7] FIG. 7 is a diagram showing an example of the functional configuration of the active power command unit 202. [Figure 8A] FIG. 8A is a graph (part 1) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when the regulation rate is linear (straight line)). [Figure 8B] FIG. 8B is a graph (part 2) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when the regulation rate is linear (straight line)). [Figure 8C] FIG. 8C is a graph (part 3) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when the regulation rate is linear (straight line)). [Figure 9A] FIG. 9A is a graph (part 1) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when the regulation rate is non-linear). [Figure 9B] FIG. 8B is a graph (part 2) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when the regulation rate is non-linear). [Figure 10A] FIG. 10A is a graph (part 1) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when applied to a power conversion device capable of bidirectional operation of charging and discharging). [Figure 10B] FIG. 10B is a graph (part 2) showing an example of a function applied to the function calculation unit in FIG. 7 (an example when applied to a power conversion device capable of bidirectional operation of charging and discharging). [Figure 11] FIG. 11 is a diagram showing an example of the functional configuration of the phase adjustment unit 11. [Figure 12] FIG. 12 is a diagram showing another example of the functional configuration of the phase adjustment unit 11. [Figure 13A] FIG. 13A is a table (part 1) for explaining that the operating state of the power conversion device 3 differs (the regulation rate and the degree of inertia simulation differ) depending on the magnitude of the charging power when charging the storage battery B, by citing three cases. [Figure 13B] FIG. 13B is a table (part 2) for explaining that the operating state of the power conversion device 3 differs (the regulation rate and the degree of inertia simulation differ) depending on the magnitude of the charging power when charging the storage battery B, by citing three cases. [Figure 14] Figure 14 is a flowchart showing an example of the operation of the power control device 2 according to the first embodiment. [Figure 15] Figure 15 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the second embodiment. [Figure 16] Figure 16 is a flowchart showing an example of the operation of the power control device 2 according to the second embodiment. [Figure 17] Figure 17 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the third embodiment. [Figure 18] Figure 18 is a flowchart showing an example of the operation of the power control device 2 according to the third embodiment. [Figure 19] Figure 19 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the fourth embodiment. [Figure 20] Figure 20 is a flowchart showing an example of the operation of the power control device 2 according to the fourth embodiment. [Modes for carrying out the invention]

[0016] The embodiments will be described below with reference to the drawings.

[0017] [First Embodiment] First, the first embodiment will be described.

[0018] Figures 1 to 3 are conceptual diagrams showing examples of the configuration of a charging facility having a power converter according to the first embodiment. Figure 1 shows the situation when the grid frequency is stable in the first embodiment, Figure 2 shows the situation when the grid frequency decreases in the same embodiment, and Figure 3 shows the situation when the grid frequency increases in the same embodiment. In Figures 1 to 3, vectors A0, A1, A2, A3, and A10, which indicate the phase angles of the signals in each part, are schematically shown on a rotating coordinate system. The phase angle when the vector on the rotating coordinate system is pointing to the right is 0°. When the vector rotates clockwise, the phase angle becomes a negative value, and when the vector rotates counterclockwise, the phase angle becomes a positive value.

[0019] The charging equipment shown in Figures 1 to 3 is, for example, a charging facility for electric vehicles.

[0020] In this embodiment, an example of "electric vehicle charging equipment" is shown, but it can also be implemented with other types of equipment, such as battery charging and discharging equipment for batteries installed alongside wind power generation, solar power generation, grid batteries, and emergency batteries, as well as charging and discharging equipment for energy storage means such as capacitors and flywheels. The fact that it is not limited to electric vehicle charging equipment will also hold true in other embodiments described later. In this embodiment, an example is shown where the electric vehicle charging equipment is connected to a "power grid," but it may be connected to another AC electrical circuit (e.g., a distribution system, a power supply circuit, etc.) instead of a power grid. In this embodiment, an example is shown where the charging equipment is equipped with a circuit breaker and a transformer and is connected to a power grid via the circuit breaker and transformer, but the circuit breaker and transformer do not have to be provided, or they may be provided outside the charging equipment (power grid, AC electrical circuit, etc.). In addition, a switchgear other than a circuit breaker (such as a switch) may be provided instead of a circuit breaker, and a reactor may be provided instead of a transformer. Furthermore, while this embodiment shows an example of adjusting the "voltage" of a power converter, it is not limited to voltage; other electrical quantities (e.g., power, current, etc.) may also be adjusted. Also, the measured value used for adjustment is not limited to the voltage value of the power system; other electrical quantities (e.g., power, current, etc.) may also be used. The value used in the adjustment calculation may be a value obtained from the measured value through calculations or functions (e.g., PLL calculation, first-order lag calculation, trigonometric functions) or the change in the measured value (Δmeasured value).

[0021] The electric vehicle charging equipment shown in Figures 1 to 3 comprises, as basic components, a transformer M, a circuit breaker CB, a power converter 1 and a power control device 2, which constitute a static power conversion device 3.

[0022] The power converter 1 is connected to the power system S via a circuit breaker CB and a transformer M. Of the electrical circuits connecting the power converter 1 and the power system S, an instrument transformer VT is installed in the electrical circuit connecting the power system S and the transformer M, and a current transformer CT1 is installed in the electrical circuit connecting the output side of the power converter 1 and the circuit breaker CB. The instrument transformer VT outputs a voltage signal corresponding to the voltage of the power system S (system voltage). The current transformer CT1 outputs a current signal corresponding to the output current of the power converter 1.

[0023] The power converter 1 functions as a charging means for charging a storage battery (energy storage means) B, for example, mounted on an electric vehicle (means of transport) 300. The power control device 2 and the electric vehicle 300 are connected by a communication circuit for transmitting information on various quantities of the storage battery B (voltage, amount of stored energy, etc.) and various quantities of the power converter 1 (output voltage, output current, etc.) from the electric vehicle 300 to the power control device. In this embodiment, an example is shown where the storage battery B is installed in the electric vehicle 300, but it is not limited to the electric vehicle 300; it may be installed in something else. In this case, it is not limited to means of transport. In this embodiment, an example is shown where information on various quantities of the storage battery B and the power converter 1 is transmitted from the electric vehicle to the power control device, but information on the storage battery B and / or the power converter 1 may also be transmitted from the power converter 1 to the power control device. Communication may also be done wirelessly without a communication circuit. Furthermore, in this embodiment, the operation and function during charging of the storage battery B from the power system S via the power converter 1 are described, but a device capable of both discharging and charging may be used. If the system is capable of both charging the battery B from the power grid S and discharging the battery B back to the power grid S, the power converter 1 is configured to operate in both the charging and discharging directions.

[0024] The power converter 1 charges the battery B from the power system S according to the signals provided from the power control device 2 via the U-phase signal generation unit 5A, V-phase signal generation unit 5B, and W-phase signal generation unit 5C, which will be described later.

[0025] The power control device 2 receives various signals, which will be described later, generates a command value for the power converter 1, and generates a signal corresponding to the command value and outputs it to the power converter 1.

[0026] This electric vehicle charging equipment is equipped with an active power and reactive power calculation unit 201, an active power command unit 202, and a reactive power command unit 203.

[0027] The active power and reactive power calculation unit 201 receives a voltage signal transmitted from an instrument transformer VT that outputs a voltage signal corresponding to the voltage of the power system S (system voltage), and a current signal transmitted from a current transformer CT that outputs a current signal corresponding to the output current of the power converter 1, and calculates and outputs the measured active power and reactive power values.

[0028] The active power command unit 202 receives signals from the charging power calculation unit (charging power calculation means) 22, the adjustment rate command unit (command means) 23, and the frequency measurement unit (frequency measurement means) 2h, which will be described later, and generates and outputs an active power command value from these signals. For example, the output of the charging power calculation unit 22 (charging power command value) is added to a value (compensation value) calculated from the adjustment rate and frequency, and the active power command value is output.

[0029] The reactive power command unit 203 outputs a reactive power command value. If there is no need to output reactive power, the setting value and output of the reactive power command unit 203 are 0.

[0030] The individual signals output from the active power and reactive power calculation unit 201, the active power command unit 202, and the reactive power command unit 203 are transmitted to various calculation units within the power control device 2. In this embodiment, the active power and reactive power calculation unit 201, the active power command unit 202, and the reactive power command unit 203 are shown as being provided in the power control device 2, but both or one of the active power and reactive power calculation unit 201 and the reactive power command unit 203 may be installed outside the power control device 2.

[0031] The power control device 2 includes a grid voltage measuring unit 2a, a phase calculation unit (phase calculation means) 2b, a voltage command value calculation unit 2c, a two-phase to three-phase conversion unit 2d, and a phase adjustment unit (phase adjustment means) 11. Furthermore, the power control device 2 includes a calculation unit 3a, a d-axis current command value calculation unit 3b, a calculation unit 3c, a calculation unit 3d, a q-axis current command value calculation unit 3e, and a calculation unit 3f to generate d and q-axis command values ​​to be given to the voltage command value calculation unit 2c, as well as a power converter current measuring unit 2f and a power converter current dq conversion unit 2g. Furthermore, the power control device 2 includes a frequency measuring unit (frequency measuring means) 2h and an inertia simulation control signal generation unit (inertia simulation control signal generation means) 2i.

[0032] The power converter current measurement unit 2f receives the current signal output from the current transformer CT1, measures the AC waveform of the inverter current of the power converter 1, and outputs the measured value (converter current measurement value).

[0033] The power converter current dq conversion unit 2g receives the converter current measurement value (3 phase) output from the power converter current measurement unit 2f, performs dq conversion (2 phase conversion), and obtains and outputs the measured values ​​of the d-axis current and q-axis current (d-axis current measurement value and q-axis current measurement value).

[0034] The calculation unit 3a receives the active power command value output from the active power command unit 202, as well as the active power measurement value output from the active power and reactive power calculation unit 201, and outputs the difference between the two (active power deviation).

[0035] The d-axis current command value calculation unit 3b receives the signal output from the calculation unit 3a, calculates the d-axis current command value from the signal, and outputs it.

[0036] The calculation unit 3c receives the d-axis current command value output from the d-axis current command value calculation unit 3b, as well as the d-axis current measurement value output from the power converter current dq conversion unit 2g, and outputs the difference between the two (d-axis current deviation).

[0037] The calculation unit 3d receives the reactive power command value output from the reactive power command unit 203, as well as the active power and the reactive power output from the reactive power calculation unit 201, and outputs the difference between the two (reactive power).

[0038] The q-axis current command value calculation unit 3e receives the difference signal output from the calculation unit 3d, calculates the q-axis current command value from the difference signal, and outputs it.

[0039] The calculation unit 3f receives the q-axis current command value output from the q-axis current command value calculation unit 3e, as well as the q-axis current measurement value output from the power converter current dq conversion unit 2g, and outputs the difference between the two (q-axis current deviation).

[0040] The system voltage measurement unit 2a receives a voltage signal supplied from the instrument transformer VT and measures the AC waveform of the system voltage from this signal. For example, this system voltage measurement unit 2a calculates and outputs the numerical value of the three-phase voltage waveform (sine wave) from the voltage signal supplied from the instrument transformer VT.

[0041] The frequency measurement unit 2h determines the frequency from the output of the system voltage measurement unit 2a and outputs it to the active power command unit 202.

[0042] The phase calculation unit 2b determines the phase of the AC waveform of the voltage measured by the system voltage measurement unit 2a. This phase calculation unit 2b, for example, performs a three-phase voltage waveform conversion (e.g., αβ conversion) on the voltage, calculates the voltage phase value, and outputs it. In this example, the phase is determined by a three-phase to two-phase conversion, but the phase may be determined by a method other than three-phase to two-phase conversion. For example, the phase may be determined by a PLL (phase-locked loop) operation.

[0043] The phase adjustment unit 11 adjusts the phase of the voltage obtained by the phase calculation unit 2b as needed. For example, the phase adjustment unit 11 applies a first-order lag calculation of angular velocity to the phase adjustment and outputs a value obtained by calculating the angular velocity value (ω) and the first-order lag value of angular velocity (ωlag) from the output (θ) of the phase calculation unit 2b, and multiplying the difference between these values ​​(ωdif = ωlag - ω) by a coefficient (K) and time (Δt) to obtain the adjusted phase value (θlag). For example, the phase adjustment unit 11 performs the following calculation to obtain the adjusted phase value (θlag).

[0044] ω = θ / Δt (Δt: sampling period) ωlag = ω / (1 + T·s) (T: first-order lag time constant, s: Laplace operator) ωdif=ωlag-ω θlag = K·ωdif·Δt Note that multiplication by the coefficient and / or Δt is not always necessary. When calculating the phase value adjusted using a phase change (e.g., Δθ) instead of angular velocity, multiplication by Δt is unnecessary. Also, when using dimensionless numbers such as pu values ​​for various numerical values, when the value of Δt is constant, or when the coefficient includes the value of Δt and is multiplied accordingly, multiplication by the coefficient and / or Δt can be omitted.

[0045] The inertia simulation control signal generation unit (inertia simulation control signal generation means) 2i generates an inertia simulation control signal to simulate the active power due to the inertia of the synchronous machine and adds it to the output (active power command value) of the active power command unit 202. The inertia simulation control signal generation unit 2i, for example, calculates the value of the trigonometric function of the difference between the output (θlag) of the phase adjustment unit 11 and the output (θ) of the phase calculation unit 2b (e.g., sin(θlag-θ)), and outputs a value obtained by multiplying the calculated value by a coefficient (e.g., K·sin(θlag-θ)) as needed.

[0046] The voltage command value calculation unit 2c calculates voltage command values ​​(e.g., d-axis voltage command value, q-axis voltage command value) for the power converter 1 based on the voltage phase determined by the phase calculation unit 2b. This voltage command value calculation unit 2c calculates and outputs voltage command values ​​from, for example, the voltage phase determined by the phase calculation unit 2b and the d-axis current deviation and q-axis current deviation calculated by the calculation units 3c and 3f.

[0047] The two-phase to three-phase conversion unit 2d generates an AC waveform of the voltage command value obtained by the voltage command value calculation unit 2c by converting the voltage command value between two phases and three phases. For example, the two-phase to three-phase conversion unit 2d converts the voltage command value obtained by the voltage command value calculation unit 2c into a command value for a three-phase voltage waveform and outputs it (for example, it calculates and outputs the values ​​obtained by converting the α-axis voltage command value and β-axis voltage command value into three-phase AC). The command values ​​for the three-phase voltage waveform generated by the two-phase to three-phase conversion unit 2d are sent to the U-phase signal generation unit 5A, the V-phase signal generation unit 5B, and the W-phase signal generation unit 5C, respectively, for the U-phase, V-phase, and W-phase.

[0048] The U-phase signal generation unit 5A, the V-phase signal generation unit 5B, and the W-phase signal generation unit 5C each generate control signals for the U-phase, V-phase, and W-phase of the power converter 1 from the command values ​​of the three-phase AC voltage waveform generated by the two-phase to three-phase conversion unit 2d, and supply the generated signals to the power converter 1 to control the voltage of the power converter 1.

[0049] In the examples shown in Figures 1 to 3, the output signal (inertia simulation control signal) of the inertia simulation control signal generation unit 2i is added in a calculation unit 3a located in the path connecting the active power command unit 202 and the d-axis current command value calculation unit 3b. However, the location where the output signal of the inertia simulation control signal generation unit 2i is added is not limited to this example. For example, it may be added in a calculation unit 3c located in the path connecting the d-axis current command value calculation unit 3b and the voltage command value calculation unit 2c, or a calculation unit may be placed at any location in the path connecting the active power command unit 202 and the voltage command value calculation unit 2c for addition, or it may be added in the active power command unit 202 or the d-axis current command value calculation unit 3b.

[0050] Specifically, the technology described in Japanese Patent Application No. 2022-132657 (hereinafter referred to as "Document A") (for example, the technology shown in Figures 28 to 31 and related descriptions of Document A) may be used. That is, the summation location of the output signal of the inertia simulation control signal generation unit 2i may be added at the summation location of the output signal of the inertia simulation control signal generation unit 15 described in Document A.

[0051] Furthermore, specific examples of calculations in the main part of the power control device 2 may also be based on the techniques described in Document A (for example, the techniques shown in Figures 33 to 45B and related descriptions in Document A).

[0052] In this embodiment, the various functions described above are used to adjust the frequency of the power grid and / or simulate inertia. For example, depending on the difference between the rated output of the power converter 1 and the power used to charge the storage battery B (hereinafter sometimes referred to as "margin power"), the degree of adjustment ratio used in the active power command unit 202 is changed, the degree of phase adjustment generated in the phase adjustment unit 11 is changed, and the degree of inertia simulation control signal generated in the inertia simulation control signal generation unit 2i is changed. To realize such control, the power control device 2 further includes a charging completion time setting unit (charging completion time setting means) 20A, a storage amount measurement unit (storage amount acquisition means) 21, a charging power calculation unit (charging power calculation means) 22, an adjustment ratio command unit (command means) 23, a phase adjustment command unit (command means) 24, and an inertia adjustment command unit (command means) 25. Some or all of these elements may be provided outside the power control device 2.

[0053] Note that the adjustment rate command unit 23, the phase adjustment command unit 24, and the inertia simulation command unit 25 are not necessarily required, and the installation of any (one or more) of these command units may be omitted. Also, the charging end time setting unit 20A is not necessarily required, and instead, a charging time setting unit (charging time setting means) 20B, which will be described later, may be installed.

[0054] The charging completion time setting unit 20A sets the charging completion time for the storage battery B. The charging completion time can be set, for example, by transmitting data to the charging completion time setting unit 20A via communication from outside the power control device 2, or by directly operating the charging completion time setting unit 20A (for example, by inputting time data).

[0055] The energy storage amount measurement unit 21 receives a signal from the electric vehicle 300 indicating the amount of energy stored in the battery B before charging begins.

[0056] The charging power calculation unit 22 calculates the required charging power for charging the battery B using at least the amount of stored energy measured or calculated by the stored energy measurement unit 21.

[0057] Specifically, the charging power calculation unit 22 calculates the charging time of the battery B from the charging end time (and charging start time) set by the charging end time setting unit 20A. The charging power calculation unit 22 also calculates the required charging power (for example, the average charging power required to fully charge the battery B within the calculated charging time) from the calculated charging time and the difference between the amount of charge stored in the battery B at the end of charging (for example, the storage capacity when fully charged) and the amount of charge measured or calculated by the storage amount measurement unit 21 (required charge amount). The charging power calculation unit 22 also calculates the adjustment range of power from the required charging power to the minimum charging power and / or maximum charging power. It should be noted that the various information used by the charging power calculation unit 22 for calculations, excluding various information input from outside the charging power calculation unit 22, is stored in a predetermined storage area.

[0058] The adjustment rate command unit 23, the phase adjustment command unit 24, and / or the inertia adjustment command unit 25 implement a function to selectively switch the calculations of the active power command unit 202, the phase adjustment unit 11, and / or the inertia simulation control signal generation unit 2i according to the charging power calculated by the charging power calculation unit 22 (for example, a function to switch the function and / or coefficient values ​​used in the calculations). In this embodiment, in addition to the stored energy measurement unit 21, a charging end time setting unit 20A and a charging power calculation unit 22 are provided, thereby enabling the selective switching of the function and / or coefficients used in various calculations according to the charging power obtained from the charging power calculation unit 22.

[0059] The adjustment rate command unit 23 has the function of changing the rate at which at least one of the charging power and discharging power of the power converter 1 changes in response to frequency changes in the power system S. Specifically, the adjustment rate command unit 23 instructs the switching of the adjustment rate according to the difference between the maximum charging power of the power converter 1 and the required charging power calculated by the charging power calculation unit 22. In this example, it instructs the active power command unit 202 to switch the adjustment rate used to generate the active power command value. For example, the active power command unit 202 stores a plurality of functions (e.g., governor-free control functions) in a predetermined memory area, each containing a different adjustment rate as a coefficient. The adjustment rate command unit 23 specifies the function to be used to generate the active power command value from among these plurality of functions and gives the active power command unit 202 an adjustment rate switching command (a command instructing to switch the adjustment rate) so that the function is used to generate the active power command value.

[0060] The phase adjustment command unit 24 has the function of switching the amount by which the output (adjusted phase) of the phase adjustment unit 11 changes in response to a phase change in the power system S, that is, the function of changing the amount of inertial response simulation of the power converter 1. Specifically, the phase adjustment command unit 24 instructs the switching of the phase adjustment function, time constant, coefficient, etc., according to the difference between the maximum charging power of the power converter 1 and the required charging power calculated by the charging power calculation unit 22. In this example, it instructs the phase adjustment unit 11 to switch the function, time constant, and coefficient for adjusting the voltage phase. For example, the phase adjustment unit 11 has a plurality of functions (e.g., first-order lag functions) each containing a different time constant (e.g., first-order lag time constant), and the phase adjustment command unit 24 specifies the function to be used for phase adjustment from among these plurality of functions and gives the phase adjustment unit 11 a function switching command (a command instructing to switch functions) so that the function to be used for phase adjustment is used. Alternatively, the phase adjustment unit 11 has a function (e.g., a first-order lag function, proportional gain) that includes a time constant (e.g., a first-order lag time constant) and a coefficient, and the phase adjustment command unit 24 specifies the values ​​of the time constant and / or coefficient to be applied to this function, and gives the phase adjustment unit 11 a command to change the time constant and / or coefficient (a command instructing it to change the values ​​of the time constant and / or coefficient) so that these values ​​of the time constant and / or coefficient are applied to the function.

[0061] The inertia adjustment command unit 25 has the function of switching the degree of the output (inertia simulation control signal) of the inertia simulation control signal generation unit 2i in response to the phase change of the power system S. Specifically, the inertia adjustment command unit 25 instructs the switching of the function, coefficients, etc. that generate the inertia simulation control signal according to the difference between the maximum charging power of the power converter 1 and the required charging power calculated by the charging power calculation unit 22. In this example, it instructs the inertia simulation control signal generation unit 2i to switch the function and coefficients used to calculate the inertia simulation control signal. For example, the inertia simulation control signal generation unit 2i stores different functions (e.g., K1·sin(θlag), K2·sin(θlag), etc.) in a predetermined memory area, and the inertia adjustment command unit 25 specifies which of these functions should be used for inertia simulation control and gives the inertia simulation control signal generation unit 2i a function switching command (a command instructing it to switch functions) so that the function should be used for inertia simulation control. Alternatively, the inertia simulation control signal generation unit 2i has a function including a coefficient (for example, K·sin(θlag)), and the inertia adjustment command unit 25 specifies the value of the coefficient (K) to be applied to this function and gives the inertia simulation control signal generation unit 2i a coefficient change command (a command instructing it to change the value of the coefficient) so that the value of this coefficient is applied to the function.

[0062] The individual functions constituting such a power control device 2 may be implemented as hardware, or some or all of them may be implemented as software (a program to be implemented by a computer).

[0063] Furthermore, the individual functions constituting the power control device 2 may be combined into one or more elements. For example, the charging power calculation unit 22 may include the functions of a charging end time setting unit (charging end time setting means) 20A, a stored energy amount measuring unit (stored energy amount acquisition means) 21, a regulating rate command unit (command means) 23, a phase adjustment command unit (command means) 24, and an inertia adjustment command unit (command means) 25.

[0064] Furthermore, if frequency adjustment is not performed, the functions related to frequency adjustment (for example, the frequency measurement unit 22 and the adjustment rate command unit 23) may be omitted. If inertia simulation control is not performed, the functions related to inertia simulation control (for example, the inertia simulation control signal generation unit 2i, the phase adjustment unit 11, the phase adjustment command unit 24, and the inertia adjustment command unit 25) may be omitted.

[0065] Furthermore, if the degree of frequency adjustment is constant, the adjustment rate command unit 23 may be omitted. If the degree of inertia simulation control is constant, either or both of the phase adjustment command unit 24 and the inertia adjustment command unit 25 may be omitted.

[0066] Next, we will explain the differences between the power converter 3 of this embodiment and the conventional power converter 3.

[0067] Figures 4 to 6 are simplified conceptual diagrams showing examples of the configuration of a charging and discharging facility with a power conversion device according to the prior art. Figure 4 shows the situation when the grid frequency is stable in the prior art, Figure 5 shows the situation when the grid frequency decreases in the prior art, and Figure 6 shows the situation when the grid frequency increases in the prior art. In Figures 4 to 6, vectors A0 and A1, which indicate the phase angles of the signals at each part, are schematically shown on a rotating coordinate system. When the vector on the rotating coordinate system is pointing to the right, the phase angle is 0°. When the vector rotates clockwise, the phase angle becomes a negative value, and when the vector rotates counterclockwise, the phase angle becomes a positive value. Note that in Figures 4 to 6, the same symbols are used for elements common to Figures 1 to 3.

[0068] In this embodiment, as shown in Figures 1 to 3, a phase adjustment unit 11, a frequency measurement unit 2h, an inertia simulation control signal generation unit 2i, a charging completion time setting unit 20A, a stored energy amount measurement unit 21, a charging power calculation unit 22, a regulating rate command unit 23, a phase adjustment unit 24, and an inertia adjustment command unit 25 are installed. In contrast, in the conventional technology, as shown in Figures 4 to 6, the phase adjustment unit 11, frequency measurement unit 2h, inertia simulation control signal generation unit 2i, a charging completion time setting unit 20A, a stored energy amount measurement unit 21, a charging power calculation unit 22, a regulating rate command unit 23, a phase adjustment unit 24, and an inertia adjustment command unit 25 are not installed. Furthermore, a charging power command unit 302 (which does not have the function of controlling charging power according to frequency) is installed instead of an active power command unit 202. Therefore, the operation of this embodiment and the conventional technology differs as described below. Note that the active power and reactive power calculation unit 201, active power command unit 202, reactive power command unit 203, power converter current measurement unit 2f, power converter current dq conversion unit 2g, d-axis current command value calculation unit 3b, q-axis current command value calculation unit 3e, and calculation units 3a, 3c, 3d, and 3f shown in Figures 1 to 3 are not necessarily required functions in the prior art and are not shown in Figures 4 to 6.

[0069] The operation of the power converter 3 while charging the battery B will be explained with reference to Figures 1 to 3 and Figures 4 to 6, comparing this embodiment with the prior art. For convenience, in the following explanation, the value of active power while the battery B is charging will be described as positive, and the value of active power while the battery B is discharging will be described as negative. For example, when a positive compensation value is added to a positive charging power command value (charging command value), the active power command value increases, and the charging power increases. When a negative compensation value is added to a positive charging power command value (charging command value), the active power command value decreases, and the charging power decreases. When a negative compensation value is added to a negative charging power command value (discharging command value), the active power command value decreases (the absolute value increases), and the discharge power increases. When a positive compensation value is added to a negative charging power command value (discharging command value), the active power command value increases (the absolute value decreases), and the discharge power decreases.

[0070] • When the system frequency is stable First, in this embodiment, the operation of the adjustment ratio inside the active power command unit 202 when the grid frequency is stable at the reference frequency will be explained. When the grid frequency is stable at the reference frequency, the compensation value calculated by the adjustment ratio and added to the charging power command value is 0pu. That is, the active power command value output from the active power command unit 202 is the same value as the charging power command value output from the charging power calculation unit 22. This is because the difference between the grid frequency and the reference frequency is 0Hz, so the compensation value calculated by the adjustment ratio and added to the charging power command value is 0pu.

[0071] Next, the operation of the phase adjustment unit 11 and the inertia simulation control signal generation unit 2i when the system frequency is stable will be described in this embodiment. When the system frequency is stable, as shown in Figure 1, the phase angle of the voltage signal of the power system S is, for example, 0° as shown by vector A0. At this time, the phase angle of the input signal of the phase adjustment unit 11 (output signal of the phase calculation unit 2b) is 0° as shown by vector A1, and the phase angle of the output signal of the phase adjustment unit 11 (phase angle of phase) is also 0° as shown by vector A2.

[0072] This is because the output signal of the phase adjustment unit 11 is not affected by the calculations of the phase adjustment unit 11 (for example, the first-order lag calculation of the angular velocity of the input signal), so the input signal and output signal of the phase adjustment unit 11 have the same phase angle. At this time, the inertia simulation control command value (for example, K·sin(0°)) output from the inertia simulation control signal generation unit 2i is 0pu. Accordingly, the value of the output of the inertia simulation control signal generation unit 2i (inertia simulation control signal) that is added to the output of the active power command unit 202 (active power command value) in the calculation unit 3a is also 0pu. Therefore, the charging power of the power converter 1 (the power used to charge the battery B) is controlled according to the active power command value, that is, according to the charging power command value.

[0073] When the grid frequency drops while battery B is being charged In this embodiment, the operation of the adjustment ratio inside the active power command unit 202 when the grid frequency drops while the storage battery B is charging will be explained. When the grid frequency is lower than the reference frequency, the compensation value calculated by the adjustment ratio becomes a negative value, and the active power command value output from the active power command unit 202 becomes a smaller value than the charging power command value output from the charging power calculation unit 22. For example, if the reference frequency is 50 Hz, the adjustment ratio is 10%, and the grid frequency drops to 49.5 Hz, the compensation value calculated by the adjustment ratio is calculated, for example, by the following formula, and the active power command value becomes a value that is -0.1 pu (-10%) smaller than the charging power command value.

[0074] (49.5Hz-50Hz) / 50Hz×(100% / 10%)=-0.1pu In other words, when the frequency of battery B decreases during charging, it reduces the charging power and acts to suppress the frequency decrease.

[0075] Next, the operation of the phase adjustment unit 11 and the inertia simulation control signal generation unit 2i when the grid frequency decreases while the storage battery B is charging will be explained in this embodiment. If the voltage phase of the grid lags behind the phase before the grid frequency decrease due to the decrease in grid frequency, then, as shown in Figure 2, the phase angle of the voltage signal of the power system S becomes, for example, -30° as shown by vector A0.

[0076] At this time, the phase angle of the input signal to the phase adjustment unit 11 (the output signal of the phase calculation unit 2b) also becomes -30° as shown by vector A1. However, the phase angle of the output signal of the phase adjustment unit 11 does not become the same as vector A1, but rather becomes, for example, -15° as shown by vector A2 (the amount of change in the phase angle is smaller for vector A2 than for vector A1).

[0077] This is because the amount of change in the output signal of the phase adjustment unit 11 is an adjusted response to the amount of change in the input signal of the phase adjustment unit 11 (for example, a response delayed by a function using a first-order lag of the angular velocity of the input signal (however, a function specified by the phase adjustment command unit 24)). If the amount of change in the input signal of the phase adjustment unit 11 (for example, angular velocity) continues to decrease, the amount of change in the output signal of the phase adjustment unit 11 will be smaller than the amount of change in the input signal. Therefore, the phase angle output from the phase adjustment unit 11 will be a value with an absolute value smaller than the phase angle input to the phase adjustment unit 11 (for example, -30°), as shown in vector A2 (for example, -15°).

[0078] At this time, the value of the inertia simulation control command output from the inertia simulation control signal generation unit 2i is a function of the difference between the phase angle of vector A1 (e.g., -30°) and the phase angle of vector A2 (e.g., -15°) (e.g., -15° (=-30°-(-15°)) (e.g., K·sin(-15°)). Consequently, a negative value is added to the active power command value in the calculation unit 3a, so the value input to the d-axis current command value calculation unit 3b becomes smaller than when the frequency is stable. Therefore, the output of the power converter 1 (charging power to charge the storage battery B) becomes smaller than when the frequency is stable.

[0079] Due to the adjustment rate within the active power command unit 202 and the action of the inertia simulation control signal generation unit 2i, the input to the power converter 1 (charging power of the storage battery B) becomes smaller when the grid frequency decreases than when the grid frequency is stable. In other words, when the frequency and / or phase of the grid voltage changes due to a decrease in the grid frequency, the power converter 1 reduces the power it inputs (charges) to suppress the decrease in grid frequency.

[0080] Furthermore, when the system frequency is stable at a lower level than the reference frequency (for example, when it is stable at 49.5 Hz), the charging power decreases due to the action of the adjustment ratio, but the inertia simulation control does not work. This is because when the frequency is stable, the value of the change in phase angle (for example, angular velocity) becomes constant, so the input signal and output signal values ​​of the phase adjustment unit 11 become the same, and the output of the inertia simulation control signal generation unit 2i becomes 0pu.

[0081] When the grid frequency increases while battery B is being charged In this embodiment, the operation of the adjustment rate inside the active power command unit 202 when the grid frequency rises while the storage battery B is being charged will be explained. When the grid frequency is higher than the reference frequency, the compensation value calculated by the adjustment rate will be a positive value, and the output of the active power command unit 202 will be a value greater than the charging power command value output from the charging power calculation unit 22. For example, if the reference frequency is 50 Hz, the adjustment rate is 10%, and the grid frequency rises to 50.5 Hz, the compensation value calculated by the adjustment rate will be calculated by, for example, the following formula, and the active power command value will be a value that is +0.1 pu (+10%) greater than the charging power command value.

[0082] (50.5Hz-50Hz) / 50Hz×(100% / 10%)=+0.1pu In other words, when the frequency increases, it increases the charging power and acts to suppress the frequency increase.

[0083] Next, the operation of the phase adjustment unit 11 and the inertia simulation control signal generation unit 2i when the system frequency increases in this embodiment will be explained. When the voltage phase of the system advances compared to the phase before the system frequency increase due to the increase in system frequency, suppose the phase angle of the voltage signal of the power system S becomes, for example, 30° as shown by vector A0, as shown in Figure 3.

[0084] At this time, the phase angle of the input signal of the phase adjustment unit 11 (the output signal of the phase calculation unit 2b) also becomes 30° as shown by vector A1. However, the phase angle of the output signal of the phase adjustment unit 11 does not become the same as vector A1, but rather becomes, for example, 15° as shown by vector A2 (the amount of change in the phase angle is smaller for vector A2 than for vector A1).

[0085] This is because the amount of change in the output signal of the phase adjustment unit 11 is an adjusted response (for example, a response delayed by a function using a first-order lag of the angular velocity of the input signal (however, a function specified by the phase adjustment command unit 24)) to the amount of change in the input signal of the phase adjustment unit 11. If the amount of change in the input signal of the phase adjustment unit 11 (for example, angular velocity) continues to increase, the amount of change in the output signal of the phase adjustment unit 11 will be smaller than the amount of change in the input signal. Therefore, the phase angle output from the phase adjustment unit 11 will be a value (for example, 15°) with an absolute value smaller than the phase angle input to the phase adjustment unit 11 (for example, 30°), as shown by vector A2.

[0086] At this time, the value of the inertia simulation control command output from the inertia simulation control signal generation unit 2i is the difference between the phase angle of vector A1 (e.g., 30°) and the phase angle of vector A2 (e.g., 15°) (e.g., 15° (=30°-15°)). Consequently, a positive value is added to the active power command value in the calculation unit 3a, so the value input to the d-axis current command value calculation unit 3b becomes larger than the value when the frequency is stable. Therefore, the input to the power converter 1 (charging power of battery B) becomes larger than when the frequency is stable.

[0087] Due to the adjustment rate within the active power command unit 202 and the action of the inertia simulation control signal generation unit 2i, the input to the power converter 1 (charging power of the storage battery B) becomes larger when the grid frequency rises than when the grid frequency is stable. In other words, when the frequency and / or phase of the grid voltage changes as the grid frequency rises, the power converter 1 increases the input (charging) power to suppress the rise in grid frequency.

[0088] Furthermore, when the system frequency is stable at a higher frequency than the reference frequency (for example, when it is stable at 50.5 Hz), the charging power increases due to the action of the adjustment ratio, but the inertia simulation control does not work. This is because when the frequency is stable, the value of the change in phase angle (for example, angular velocity) becomes constant, so the input signal and output signal values ​​of the phase adjustment unit 11 become the same, and the output of the inertia simulation control signal generation unit 2i becomes 0pu.

[0089] Furthermore, in this embodiment, the charging completion time setting unit 20A, the stored energy measurement unit 21, the charging power calculation unit 22, the adjustment rate command unit 23, the phase adjustment command unit 24, and the inertia adjustment command unit 25 work together to appropriately control the degree of the adjustment rate used in the active power command unit 202 and / or the degree of phase adjustment used in the phase adjustment unit 11, according to the available power when charging the storage battery B. As a result, the range of change in the input (charging) of the power converter 1 is appropriately adjusted.

[0090] On the other hand, in the conventional technology, when the grid frequency is stable, the phase angles shown by vectors A0 and A1 are the same as when the grid frequency is stable in the embodiment described in Figure 1, as shown in Figure 4. However, in the conventional technology, when the grid frequency decreases, as shown in Figure 5, the phase adjustment unit 11, frequency measurement unit 2h, inertia simulation control signal generation unit 2i, charging end time setting unit 20A, stored energy measurement unit 21, charging power calculation unit 22, adjustment rate command unit 23, phase adjustment unit 24, and inertia adjustment command unit 25 are absent, and a charging power command unit 302 is provided instead of an active power command unit 202. As a result, the control operation of the power control device 11 differs from that of the embodiment described in Figure 2.

[0091] In other words, in the conventional technology, there is no frequency measurement unit 2h and no control function based on a regulating ratio, so even if the grid frequency decreases, the charging power control is not performed in accordance with the frequency decrease. Also, since there is no phase adjustment unit 11, inertia simulation control signal generation unit 2i, etc., even if the phase of the grid voltage changes, the charging power control (inertia simulation control) is not performed in accordance with the phase change. Therefore, the input to the power converter 1 and the charging power of the storage battery B remain unchanged from when the grid frequency and phase are stable, and this does not suppress the decrease in grid frequency.

[0092] Next, we will explain the operation of battery B while it is discharging, comparing this embodiment with the prior art. Illustrations are omitted here.

[0093] When the grid frequency drops while battery B is discharging In this embodiment, the operation of the adjustment ratio inside the active power command unit 202 when the grid frequency drops while the storage battery B is discharging will be explained. When the grid frequency is lower than the reference frequency, the compensation value calculated by the adjustment ratio becomes a negative value, and the output of the active power command unit 202 becomes a value with an absolute value greater than the charging power command value (a negative value during discharge) output from the charging power calculation unit 22. For example, if the reference frequency is 50 Hz, the adjustment ratio is 10%, and the grid frequency drops to 49.5 Hz, the compensation value calculated by the adjustment ratio is calculated by, for example, the following formula, and the active power command value becomes a value that is -0.1 pu (-10%) smaller (a value with an absolute value that is 0.1 pu larger) than the charging power command value (a negative value during discharge).

[0094] (49.5Hz-50Hz) / 50Hz×(100% / 10%)=-0.1pu In other words, if the frequency of battery B decreases during discharge, it increases the discharge power to suppress the frequency decrease. During discharge, the charge power command value is a negative value, so the larger the absolute value, the greater the discharge power.

[0095] Next, the operation of the phase adjustment unit 11 and the inertia simulation control signal generation unit 2i when the grid frequency decreases while the storage battery B is discharging will be explained in this embodiment. If the voltage phase of the grid lags behind the phase before the grid frequency decrease due to the decrease in grid frequency, then, as shown in Figure 2, the phase angle of the voltage signal of the power system S may become, for example, -30° as shown by vector A0.

[0096] At this time, the phase angle of the input signal to the phase adjustment unit 11 (the output signal of the phase calculation unit 2b) also becomes -30° as shown by vector A1. However, the phase angle of the output signal of the phase adjustment unit 11 does not become the same as vector A1, but rather becomes, for example, -15° as shown by vector A2 (the amount of change in the phase angle is smaller for vector A2 than for vector A1).

[0097] This is because the amount of change in the output signal of the phase adjustment unit 11 is an adjusted response to the amount of change in the input signal of the phase adjustment unit 11 (for example, a response delayed by a function using a first-order lag of the angular velocity of the input signal (however, a function specified by the phase adjustment command unit 24)). If the amount of change in the input signal of the phase adjustment unit 11 (for example, angular velocity) continues to decrease, the amount of change in the output signal of the phase adjustment unit 11 will be smaller than the amount of change in the input signal. Therefore, the phase angle output from the phase adjustment unit 11 will be a value with an absolute value smaller than the phase angle input to the phase adjustment unit 11 (for example, -30°), as shown in vector A2 (for example, -15°).

[0098] At this time, the value of the inertia simulation control command output from the inertia simulation control signal generation unit 2i is a function of the difference between the phase angle of vector A1 (e.g., -30°) and the phase angle of vector A2 (e.g., -15°) (e.g., -15° (=-30°-(-15°)) (e.g., K·sin(-15°)). Consequently, a negative value is added to the active power command value (a negative value during discharge) in the calculation unit 3a, so the value input to the d-axis current command value calculation unit 3b becomes a value with a larger absolute value than when the frequency is stable. Therefore, the output of the power converter 1 (discharge power of battery B) becomes larger than when the frequency is stable.

[0099] Due to the adjustment rate within the active power command unit 202 and the action of the inertia simulation control signal generation unit 2i, the output of the power converter 1 (discharge power of the storage battery B) becomes greater when the grid frequency decreases than when the grid frequency is stable. In other words, when the frequency and / or phase of the grid voltage changes due to a decrease in the grid frequency, the power converter 1 increases the power it outputs (discharges) to suppress the decrease in grid frequency.

[0100] Furthermore, when the system frequency is stable at a lower level than the reference frequency (for example, when it is stable at 49.5 Hz), the discharge power increases due to the effect of the adjustment ratio, but the inertia simulation control does not work. This is because when the frequency is stable, the value of the change in phase angle (for example, angular velocity) becomes constant, so the input signal and output signal values ​​of the phase adjustment unit 11 become the same, and the output of the inertia simulation control signal generation unit 2i becomes 0pu.

[0101] When the grid frequency increases while battery B is discharging In this embodiment, the operation of the adjustment ratio inside the active power command unit 202 when the grid frequency rises while the storage battery B is discharging will be explained. When the grid frequency is higher than the reference frequency, the compensation value calculated by the adjustment ratio becomes a positive value, and the output of the active power command unit 202 becomes a value greater than the charge power command value (a negative value during discharge) output from the charge power calculation unit 22. For example, if the reference frequency is 50 Hz, the adjustment ratio is 10%, and the grid frequency rises to 50.5 Hz, the compensation value calculated by the adjustment ratio is calculated by, for example, the following formula, and the active power command value becomes a value that is +0.1 pu (+10%) greater (a value that is 0.1 pu smaller in absolute value) than the charge power command value (a negative value during discharge).

[0102] (50.5Hz-50Hz) / 50Hz×(100% / 10%)=+0.1pu In other words, if the frequency of battery B increases during discharge, it will reduce the discharge power and act to suppress the frequency increase. During discharge, the charge power command value is a negative value, so the smaller the absolute value, the smaller the discharge power.

[0103] Next, in this embodiment, the operation of the phase adjustment unit 11 and the inertia simulation control signal generation unit 2i when the grid frequency rises while the storage battery B is discharging will be explained. When the grid voltage phase advances compared to the phase before the grid frequency rise due to the increase in grid frequency, suppose the phase angle of the voltage signal of the power system S becomes, for example, 30° as shown by vector A0, as shown in Figure 3.

[0104] At this time, the phase angle of the input signal of the phase adjustment unit 11 (the output signal of the phase calculation unit 2b) also becomes 30° as shown by vector A1. However, the phase angle of the output signal of the phase adjustment unit 11 does not become the same as vector A1, but rather becomes, for example, 15° as shown by vector A2 (the amount of change in the phase angle is smaller for vector A2 than for vector A1).

[0105] This is because the amount of change in the output signal of the phase adjustment unit 11 is an adjusted response (for example, a response delayed by a function using a first-order lag of the angular velocity of the input signal (however, a function specified by the phase adjustment command unit 24)) to the amount of change in the input signal of the phase adjustment unit 11. If the amount of change in the input signal of the phase adjustment unit 11 (for example, angular velocity) continues to increase, the amount of change in the output signal of the phase adjustment unit 11 will be smaller than the amount of change in the input signal. Therefore, the phase angle output from the phase adjustment unit 11 will be a value (for example, 15°) with an absolute value smaller than the phase angle input to the phase adjustment unit 11 (for example, 30°), as shown in vector A2.

[0106] At this time, the value of the inertia simulation control command output from the inertia simulation control signal generation unit 2i is a function of the difference between the phase angle of vector A1 (e.g., 30°) and the phase angle of vector A2 (e.g., 15°) (e.g., 15° (=30°-15°)) (e.g., K·sin(15°)). Consequently, a positive value is added to the active power command value (a negative value during discharge) in the calculation unit 3a, so the value input to the d-axis current command value calculation unit 3b becomes smaller in absolute value than when the frequency is stable. Therefore, the output of the power converter 1 (discharge power of battery B) becomes smaller than when the frequency is stable.

[0107] Due to the adjustment rate within the active power command unit 202 and the action of the inertia simulation control signal generation unit 2i, the output of the power converter 1 (discharge power of the storage battery B) becomes smaller when the grid frequency increases than when the grid frequency is stable. In other words, when the frequency and / or phase of the grid voltage changes as the grid frequency increases, the power converter 1 reduces the power it outputs (discharges) to suppress the increase in grid frequency.

[0108] Furthermore, when the system frequency is stable at a higher frequency than the reference frequency (for example, when it is stable at 50.5 Hz), the charging power increases due to the action of the adjustment ratio, but the inertia simulation control does not work. This is because when the frequency is stable, the value of the change in phase angle (for example, angular velocity) becomes constant, so the input signal and output signal values ​​of the phase adjustment unit 11 become the same, and the output of the inertia simulation control signal generation unit 2i becomes 0pu.

[0109] Furthermore, in this embodiment, the charging completion time setting unit 20A, the stored energy measurement unit 21, the charging power calculation unit 22, the adjustment rate command unit 23, the phase adjustment command unit 24, and the inertia adjustment command unit 25 work together to appropriately control the degree of the adjustment rate used in the active power command unit 202 and / or the degree of phase adjustment used in the phase adjustment unit 11, according to the available power when discharging the storage battery B. As a result, the range of change in the output (discharge) of the power converter 1 is appropriately adjusted.

[0110] On the other hand, in the conventional technology, as shown in Figure 5, there is no phase adjustment unit 11, frequency measurement unit 2h, inertia simulation control signal generation unit 2i, charging end time setting unit 20A, stored energy measurement unit 21, charging power calculation unit 22, adjustment rate command unit 23, phase adjustment unit 24, and inertia adjustment command unit 25, and a charging power command unit 302 is provided instead of an active power command unit 202. Therefore, even if the grid frequency drops and the phase of the grid voltage changes while the storage battery B is discharging, the power output (discharged) from the power converter 1 does not change, and thus the decrease in grid frequency is not suppressed.

[0111] In the conventional technology, as shown in Figure 5, the phase adjustment unit 11, frequency measurement unit 2h, inertia simulation control signal generation unit 2i, charging end time setting unit 20A, stored energy measurement unit 21, charging power calculation unit 22, adjustment rate command unit 23, phase adjustment unit 24, and inertia adjustment command unit 25 are absent, and a charging power command unit 302 is provided instead of an active power command unit 202. Therefore, even if the grid frequency rises and the phase of the grid voltage changes while the storage battery B is discharging, the power output (discharged) from the power converter 1 does not change, and thus the rise in grid frequency is not suppressed.

[0112] In the above example, we showed a case where the voltage waveform (sine wave) is converted from three to two phases to obtain the voltage phase, and a first-order lag calculation of the angular velocity of the phase is used for phase adjustment. However, the phase of an electrical quantity other than voltage (power, current, etc.) may also be used. Furthermore, although the above example showed how to obtain the phase by three-phase to two-phase conversion, the phase may also be obtained by methods other than three-phase to two-phase conversion. For example, the phase may be obtained by PLL (phase-locked loop) calculation. In addition, calculations (functions) other than the first-order lag calculation may be used for phase adjustment. For example, a PLL (phase-locked loop) calculation with adjusted tracking speed or a second-order lag calculation may be used, or a function that fixes the phase value for a certain period of time and then tracks the phase of the system after that period of time may be used to obtain the same effect as the first-order lag. Instead of the phase, the value or change (Δθ) of the trigonometric function of the phase (e.g., cosθ, sinθ) may be obtained and used in various calculations.

[0113] Next, we will explain how to switch the degree of frequency fluctuation suppression by switching the adjustment rate. Figure 7 shows an example of the functional configuration of the active power command unit 202.

[0114] As shown in Figure 7, the active power command unit 202 has multiple function calculation units R1, R2, R3 and switching units SW1, SW2, SW3. By providing these various elements, it becomes possible to selectively switch between multiple operating states, which will be described later.

[0115] The function calculation unit R1 has a first function (governor-free control function) that includes, for example, a tuning ratio of 5%, and uses this first function to calculate and output the corresponding active power command value from the input frequency. The tuning ratio included in this first function is smaller than the tuning ratio included in the second function, which will be described later.

[0116] The function calculation unit R2 has a second function (governor-free control function) which includes, for example, an 8% adjustment factor, and uses this second function to calculate and output the corresponding active power command value from the input frequency. The adjustment factor included in this second function is greater than the adjustment factor included in the first function and less than the adjustment factor included in the third function, which will be described later.

[0117] The function calculation unit R3 has a third function (governor-free control function) that includes, for example, a 20% adjustment factor, and uses this third function to calculate and output the corresponding active power command value from the input frequency. The adjustment factor included in this third function is greater than the adjustment factor included in the second function.

[0118] The switching units SW1, SW2, and SW3 are located in the paths connecting the function calculation unit R1 to the output side, the function calculation unit R2 to the output side, and the function calculation unit R3 to the output side, respectively, and can be in an open or closed state. One of the switching units SW1, SW2, or SW3 is selectively closed according to a setting rate command provided by the setting rate command unit 23, allowing the signal to pass through.

[0119] For example, if switch SW1 is closed and switch SW2 and SW3 are open, the first function with a larger adjustment factor will be used. When using the first function, the effect of frequency adjustment is smaller than when using the second function.

[0120] Furthermore, when switch SW2 is closed and switch SW1 and SW3 are open, a second function with a medium-sized adjustment ratio is used. When using the second function, the frequency adjustment effect is greater than when using the first function, but less than when using the third function.

[0121] Furthermore, by closing switch SW3 and opening switch SW1 and SW2, a third function with a smaller adjustment ratio will be used. When using the third function, the frequency adjustment effect is greater than when using the second function.

[0122] Figures 8A, 8B, 8C, 9A, 9B, 10A, and 10B are graphs showing examples of functions applied to the function calculation units R1, R2, and R3 in Figure 7, respectively. All examples are for cases where the maximum charging power is 10kW and the minimum power is 0kW. Figures 8A, 8B, and 8C are examples where the adjustment ratio is linear (straight line). Figures 9A and 9B are examples where the adjustment ratio is nonlinear. Figures 10A and 10B are examples of applications to a power converter capable of bidirectional charging and discharging.

[0123] The graphs in Figures 8A, 8B, and 8C show examples of functions (first, second, and third functions) that change the adjustment rate according to the charging power command value, where the adjustment rate is linear (straight line). In all three figures, Figures 8A, 8B, and 8C show examples where the adjustment rate is set so that the charging power becomes 0kW when the frequency drops to 48Hz. The adjustment rate in Figure 8A is 20%, in Figure 8B it is 8%, and in Figure 8C it is 5%.

[0124] The graph in Figure 8A represents a function with a 20% adjustment ratio (the first function). For example, when the charging power command value when charging battery B is relatively small (e.g., 2kW), the power adjustment range Rb (in the direction of decreasing charging power) that can be used to suppress frequency drop becomes narrow (e.g., Rb = 2kW). In such cases, the first function shown in the graph of Figure 8A is applied. For example, when the frequency drops from 50Hz to 49Hz, the charging power decreases from 2kW to 1kW, suppressing the frequency drop. For example, when the frequency rises from 50Hz to 51Hz, the charging power increases from 2kW to 3kW, suppressing the frequency rise.

[0125] The graph in Figure 8B represents a function (second function) with a regulating factor of 8%. For example, when the magnitude of the charging power command value when charging battery B is moderate (e.g., 5kW), the power adjustment range Ra (increasing charging power) that can be used to suppress frequency rise is moderate (e.g., Ra=5kW), and the power adjustment range Rb (decreasing charging power) that can be used to suppress frequency fall is also moderate (e.g., Rb=5kW). In such cases, the second function shown in the graph of Figure 8B is applied. For example, when the frequency decreases from 50Hz to 49Hz, the charging power decreases from 5kW to 2.5kW, suppressing the frequency fall. For example, when the frequency increases from 50Hz to 51Hz, the charging power increases from 5kW to 7.5kW, suppressing the frequency rise.

[0126] The graph in Figure 8C represents a function (third function) with a 5% adjustment ratio. For example, when the charging power when charging battery B is relatively large (e.g., 8kW), the adjustment range Rb (in the direction of decreasing charging power) that can be used to suppress frequency drop becomes wider (e.g., Rb = 8kW). In such cases, the third function shown in the graph of Figure 8C is applied. For example, when the frequency drops from 50Hz to 49Hz, the charging power decreases from 8kW to 4kW, suppressing the frequency drop. For example, when the frequency rises from 50Hz to 51Hz, the charging power increases from 8kW to 10kW, suppressing the frequency rise.

[0127] While switching the adjustment rate according to the charging power command value is not mandatory, it is preferable to switch the adjustment rate according to the charging power command value in order to effectively suppress frequency fluctuations while maintaining the charging power above a predetermined value. For example, if the adjustment rate is constant at 5% and the charging power command value is 2kW, when the frequency drops below 49.5Hz, the charging power becomes 0kW and charging cannot be continued. Also, for example, if the adjustment rate is constant at 20% and the charging power command value is 8kW, the change in charging power when the frequency drops to 49Hz is 1kW, and the adjustment range Rb(8kW) cannot be fully utilized. Therefore, it is desirable to switch the adjustment rate according to the charging power command value and the expected frequency fluctuation range.

[0128] In the examples above, we described cases where the charging power command value was 8kW, 5kW, and 2kW, but the charging power command value may be a value other than 8kW, 5kW, or 2kW. Also, in the examples above, we described an example where the adjustment rate was set based on the relationship between the frequency value (e.g., 48Hz) and the charging power value (e.g., 0kW) when the frequency is decreasing, but the adjustment rate may also be set based on the relationship between the frequency value and the charging power value when the frequency is increasing. Furthermore, in the examples above, we described cases where the adjustment rate was 20%, 8%, and 5%, but the adjustment rate may be a value other than 20%, 8%, or 5%.

[0129] The graphs in Figures 9A and 9B show examples of functions where the adjustment rate is represented as a line graph, and the adjustment rate differs for the frequency decrease side and the frequency increase side. Both Figures 9A and 9B show examples where the adjustment rate is set so that the charging power becomes 0kW when the frequency decreases to 48Hz.

[0130] For example, when the charging power command value for battery B is relatively small (e.g., 2kW), the power adjustment range Ra (increasing charging power) that can be used to suppress frequency rise is wide (e.g., Ra = 8kW), and the power adjustment range Rb (decreasing charging power) that can be used to suppress frequency fall is narrow (e.g., Rb = 2kW). In such cases, the function shown in the graph of Figure 9A is applied. For example, when the frequency drops from 50Hz to 49Hz, the charging power decreases from 2kW to 1kW, suppressing the frequency fall. For example, when the frequency rises from 50Hz to 51Hz, the charging power increases from 2kW to 6kW, suppressing the frequency rise.

[0131] For example, when the charging power command value for battery B is relatively large (e.g., 8kW), the adjustment range Ra (increasing charging power) that can be used to suppress frequency rise is narrow (e.g., Ra=2kW), and the adjustment range Rb (decreasing charging power) that can be used to suppress frequency fall is wide (e.g., Rb=8kW). In such cases, the function shown in the graph of Figure 9B is applied. For example, when the frequency drops from 50Hz to 49Hz, the charging power decreases from 8kW to 4kW, suppressing the frequency fall. For example, when the frequency rises from 50Hz to 51Hz, the charging power increases from 8kW to 9kW, suppressing the frequency rise.

[0132] While using a piecewise linear adjustment ratio is not mandatory, it is preferable to use one in order to effectively suppress frequency fluctuations while keeping the charging power within a predetermined range. For example, if the charging power command value is 2kW and the adjustment ratio is constant at 5%, when the frequency drops below 49.5Hz, the charging power becomes 0kW (the change in charging power is 2kW), making it impossible to continue charging. However, with a nonlinear adjustment ratio, when the frequency drops to 49.5Hz, the charging power is 1.5kW (the change in charging power is 5kW), and charging can be continued. Also, for example, if the charging power command value is 8kW and the adjustment ratio is constant at 20%, when the frequency drops to 49.5Hz, the charging power is 1.5kW (change = 0.5kW), and the adjustment range Rb (8kW) cannot be fully utilized. However, with a nonlinear adjustment ratio (for example, 5% below the charging power command value), when the frequency drops to 49.5Hz, the charging power is 6kW (change = 2kW), and a frequency fluctuation suppression effect four times greater than when the adjustment ratio is constant at 20% can be obtained.

[0133] The above examples described cases where the charging power command value was 2kW and 8kW, but the charging power command value can be any value other than 2kW and 8kW. Also, the above examples described an example where the adjustment rate was set so that the charging power becomes 0kW when the frequency drops to 48Hz, but the charging power when the frequency drops to 48Hz can be any value other than 0kW. Also, the above examples described cases where the adjustment rate was 5% and 20%, but the adjustment rate can be any value other than 5% and 20%.

[0134] The graphs in Figures 10A and 10B show examples of functions applicable to a power converter capable of bidirectional charging and discharging. Figure 10A represents an example of a function with a regulating ratio of 5%, and Figure 10B represents an example of a function with a regulating ratio of 2.5%. The range of Rc (0 to 10 kW) is the range in which the power converter charges the battery, and the range of Rd (-10 to 0 kW) is the range in which the battery discharges (the range in which the power converter supplies power to the power grid). For example, if the regulating ratio is 5% and the charging power command value is 6 kW, when the frequency drops to 49 Hz, the charging power decreases to 2 kW, suppressing the frequency drop. For example, if the regulating ratio is 2.5% and the charging power command value is 6 kW, when the frequency drops to 49 Hz, the discharge power becomes 2 kW (charging power is -2 kW), suppressing the frequency drop.

[0135] In the example above, we described an example where the charging power command value is 6kW, but the charging power command value can be a value other than 6kW, or a negative value (discharge side value). Also, in the example above, we described examples where the adjustment rate is 5% and 2.5%, but the adjustment rate value can be a value other than 5% and 2.5%. Furthermore, in the example above, we described an example where the adjustment rate is linear (straight line), but a piecewise linear adjustment rate can also be used.

[0136] In the examples shown in Figures 8A, 8B, 8C, 9A, 9B, 10A, and 10B above, we described examples of functions where the tuning rate is linear (straight line) or where there is a single inflection point in a polyline. However, there can be multiple inflection points or the function can be a curve. Furthermore, the tuning rate may have a dead zone (for example, an infinite tuning rate in the range of 49.9Hz to 50.1Hz (a horizontal straight line)). Also, for convenience, the function was shown graphically in the above explanation, but the function can also be a formula, table, algorithm, or program that calculates the charging power (or charge / discharge power) from the frequency.

[0137] Next, we will explain how to switch the degree of inertial response simulation control by switching the phase adjustment amount. Figure 11 shows an example of the functional configuration of the phase adjustment unit 11.

[0138] As shown in Figure 11, the phase adjustment unit 11 has multiple function calculation units F1, F2, a limit value calculation unit L1, a limit value priority calculation unit P1, and switching units SWa, SWb, SWc, SWd. By providing these various elements, it becomes possible to selectively switch between multiple functions, which will be described later. Specifically, the function calculation units F1 and F2 may use the techniques described in reference A (for example, the techniques shown in Figures 35A to 44B and related descriptions in reference A).

[0139] The function calculation unit F1 outputs the result of delaying the phase of the input signal using a first function. This first function includes, for example, angular velocity calculation and first-order angular velocity lag calculation. The value of the time constant T1 of this first-order lag calculation is smaller than the value of the time constant T2 of the first-order lag calculation described later (the phase delay of the output relative to the input phase is small).

[0140] The function calculation unit F2 outputs the result of delaying the phase of the input signal using a second function. This second function includes, for example, angular velocity calculation and first-order lag calculation. The value of the time constant T2 of this first-order lag calculation is larger than the value of the time constant T1 of the first-order lag calculation mentioned above (the phase delay of the output relative to the input phase is large).

[0141] The limit value calculation unit L1 outputs the result of limiting the phase value of the input signal by an upper limit and / or lower limit.

[0142] The limit value priority calculation unit P1 receives the output signal from either the function calculation unit F1 or the function calculation unit F2, as well as the output signal from the limit value calculation unit L1, and prioritizes outputting the signal whose value falls within the limit (for example, the signal with the smaller absolute value).

[0143] Switching units SWa, SWb, and SWc are provided in the paths connecting the first function calculation unit F1 and the limit value priority calculation unit P1, the second function calculation unit F2 and the limit value priority calculation unit P1, and the limit value calculation unit L1 and the limit value priority calculation unit P1, respectively, and can be in an open or closed state.

[0144] One of the switching units SWa, SWb, and SWd is selectively closed by a function switching command provided by the phase adjustment command unit 24. Switching unit SWc is open or closed by a switching command provided by the phase adjustment command unit 24. When switching unit SWc is open, if the input phase change range is large, the difference between the input phase and the output phase may become excessive. However, by closing SWc, the difference between the input phase and the output phase can be limited to within a limit value.

[0145] The switch SWd is located in a bypass circuit that outputs the signal without adjusting the input phase, and can be either open or closed. If phase adjustment is not required, closing switch SWd and opening switch SWa, SWb, and SWc will output the same signal as the input signal.

[0146] The limit value priority calculation unit P1 receives the output signal of the corresponding function calculation unit F1 or F2 when the switching unit SWa or SWb is in the closed state, and the output signal of the limit value calculation unit L1. If the value of the output signal of the function calculation unit F1 or F2 is outside the limit range, it prioritizes outputting the signal of the limit value calculation unit L1. For example, if the output of the limit value calculation unit L1 is ±0.1pu of the input value and the input value is 1pu, then if the value of the output signal of the function calculation unit F1 or F2 exceeds 1.1pu, it outputs 1pu. For example, if the output of the limit value calculation unit L1 is ±0.1pu of the input value and the input value is -1pu, then if the value of the output signal of the function calculation unit F1 or F2 is less than -1.1pu, it outputs -1pu.

[0147] For example, if the switching unit SWa is closed and the switching units SWb and SWd are open, the first function with a small first-order lag time constant will be used. When the first function is used, the effect of simulating the inertial response (suppressing transient frequency changes) is smaller than when the second function is used.

[0148] Furthermore, by closing the switching unit SWb and opening the switching units SWa and SWd, a second function with a larger first-order lag time constant will be used. When using the second function, the effect of simulating the inertial response (suppressing transient frequency changes) is greater than when using the first function. When simulating the inertial response of a synchronous machine, it is desirable that the adjustment ranges for increasing and decreasing the charging power due to the inertial response simulation be equal. For convenience, the following will describe an example in which the adjustment ranges for increasing and decreasing the charging power are equal.

[0149] For example, when the charging power used to charge battery B is relatively large (e.g., 8kW), the range of power adjustment available for simulating the inertial response is narrow (e.g., ±2kW). In such cases, the function of the first function calculation unit F1 (the first function) is applied.

[0150] Furthermore, when the charging power for battery B is moderate (for example, 5kW), the range of power adjustment that can be used for inertial response simulation is wider (for example, ±5kW) than when the charging power is relatively large (for example, ±2kW). In such cases, the function of the second function calculation unit F2 (the second function) is applied.

[0151] Furthermore, when the charging power for battery B is relatively small (for example, 2kW), the power adjustment range that can be used for frequency adjustment is narrow (for example, ±2kW). In such cases, the function of the first function calculation unit F1 (the first function) is applied.

[0152] In the example above, for convenience, we described an example where the adjustment ranges for increasing and decreasing charging power are set to be equal (e.g., ±2kW or ±5kW). However, the adjustment ranges for increasing and decreasing charging power may be unequal. For example, when the charging power is 8kW, a function with a large first-order lag time constant may be applied. In this case, for example, the adjustment range for increasing charging power (e.g., +2kW) and the adjustment range for decreasing charging power (e.g., -5kW) will be unequal. Although it is not possible to simulate the inertial response of a synchronous machine, the effect of suppressing frequency drop will be greater than when the adjustment ranges are uniform (e.g., ±2Hz).

[0153] Figure 12 shows another example of the functional configuration of the phase adjustment unit 11.

[0154] As shown in Figure 12, the phase adjustment unit 11 includes a function calculation unit F, a limit value calculation unit L1, and a limit value priority calculation unit P1.

[0155] The function calculation unit F outputs the result of delaying the phase of the input signal using a function. This function includes, for example, a first-order lag calculation. The first-order lag time constant T of the first-order lag calculation can be changed as a coefficient of the function.

[0156] The limit value calculation unit L1 outputs the result of limiting the phase value of the input signal by an upper limit and / or lower limit.

[0157] The limit value priority calculation unit P1 receives the output signal of the function calculation unit F as well as the output signal of the limit value calculation unit L1, and prioritizes outputting the signal whose value is within the limit (for example, the signal with the smaller absolute value).

[0158] The value of the coefficient (first-order lag time constant T) included in the function of the function calculation unit F is changed by a coefficient change command given by the phase adjustment command unit 24.

[0159] For example, setting the coefficient (first-order lag time constant T) to a large value increases the effect of inertial response simulation (suppression of transient frequency changes). On the other hand, setting the coefficient (first-order lag time constant T) to a small value decreases the effect of inertial response simulation. When the coefficient (first-order lag time constant T) is set to 0, the output waveform of the phase adjustment unit 11 becomes the same as the input waveform of the phase adjustment unit 11, so inertial response simulation is not performed, and control is performed in the same way as the conventional power converter 3.

[0160] Furthermore, the specific calculations in the aforementioned inertia simulation control signal generation unit 2i may utilize the technology of the inertia simulation control signal generation unit 15 described in reference A (for example, the technology shown in Figures 45A, 45B, and related descriptions in reference A).

[0161] The inertia simulation control signal generation unit 2i receives a signal (inertia simulation control signal θdif) indicating the difference between the phase (θ) obtained by the phase calculation unit 2b and the phase (θlag) after adjustment by the phase adjustment unit 11, and generates values ​​by applying a function (e.g., sinθ) to transform the value, multiplying by a coefficient, or converting to a pu value as needed. The inertia simulation control signal generation unit 2i generates an inertia simulation control signal (Pvic) by performing the following calculations, for example.

[0162] θdif = θlag - θ Pvic = sin(θdif) (Example of using a function for θdif to convert it into an inertia-simulating control signal) Pvic = K·θdif (Example of multiplying θdif by a coefficient to convert it into an inertia-simulating control signal) Pvic = K·θdif / (2·π) (An example of converting θdif to a pu value and then multiplying it by a coefficient to obtain a simulated inertia control signal) Pvic = K·sin(θdif) For convenience, the following example will describe a case where the adjustment ranges for increasing and decreasing charging power are equal. For example, when the charging power when charging battery B is relatively large (e.g., 8kW), the power adjustment range that can be used for simulating the inertial response is narrow (e.g., ±2kW). In such cases, a small coefficient (first-order lag time constant T) is applied.

[0163] Furthermore, when the charging power for battery B is moderate (for example, 5kW), the range of power adjustment that can be used for simulating the inertial response is wider (for example, ±5kW) than when the charging power is relatively large (for example, ±2kW). In such cases, a larger coefficient (first-order lag time constant T) is applied.

[0164] Furthermore, when the charging power for battery B is relatively small (for example, 2kW), the range of power adjustment available for simulating the inertial response is narrow (for example, ±2kW). In such cases, a small coefficient (first-order lag time constant T) is applied.

[0165] Next, referring to Figures 13A and 13B, we will explain, using three cases, how the operating state of the power converter 3 differs (the regulating rate and the degree of inertia simulation differ) depending on the magnitude of the charging power when charging the storage battery B.

[0166] As an example for Case No. 1, let's assume that the charging start time is 0:00, the charging end time is 5:00, the battery capacity when fully charged is 50kWh, the amount of charge at the start of charging is 10kWh, and the maximum charging power of the power converter 3 is 10kW. The charging end time (5:00) is set by the charging end time setting unit 20A. The required charge amount (40kWh) is transmitted, for example, from the electric vehicle (means of transport) 300 to the charge amount measurement unit 21. The average charging power is calculated by the charging power calculation unit 22 based on the required charge amount and charging time. The required charge amount may also be measured or calculated by the charge amount measurement unit 21 using data transmitted from the electric vehicle (means of transport) 300.

[0167] In this case, the charging power calculation unit 22 calculates the charging time (5 hours) from the difference between the charging end time (5 o'clock) and the charging start time (0 o'clock), calculates the average charging power (40 kWh / 5 hours = 8 kW) from the charging time (5 hours), the battery capacity when fully charged (50 kWh), and the amount of stored energy at the start of charging (10 kWh), and further calculates the adjustment range (8 kW) of the charging power from this average charging power (8 kW) to the minimum charging power (0 kW).

[0168] Based on these calculation results, the adjustment rate command unit 23 instructs the active power command unit 202 to switch the adjustment rate or set a value for the adjustment rate so that a function and / or adjustment rate is applied such that the charging power for a predetermined frequency drop (for example, a drop from 50Hz to 2Hz) is a predetermined value (for example, so that control is performed using a small adjustment rate of 5% (Figure 13A, Case No. 1)). The phase adjustment command unit 24 also instructs the phase adjustment unit 11 to switch the function or set a value for the coefficient (first-order lag time constant T) so that a function and / or time constant is applied such that the fluctuation range of the fluctuating power is ±2kW or less in the inertial response simulation (for example, so that phase adjustment is performed using a first function having a small first-order lag time constant T (Figure 13B, Case No. 1)).

[0169] As an example for Case No. 2, let's assume that the charging start time is 0:00, the charging end time is 5:00, the battery capacity when fully charged is 50kWh, the amount of charge at the start of charging is 25kWh, and the maximum charging power of the power converter 3 is 10kW. The charging end time (5:00) is set by the charging end time setting unit 20A. The required charge amount (25kWh) is transmitted, for example, from the electric vehicle (means of transport) 300 to the charge amount measurement unit 21. The average charging power is calculated by the charging power calculation unit 22 based on the required charge amount and charging time. The required charge amount may also be measured or calculated by the charge amount measurement unit 21 using data transmitted from the electric vehicle (means of transport) 300.

[0170] In this case, the charging power calculation unit 22 calculates the charging time (5 hours) from the difference between the charging end time (5 o'clock) and the charging start time (0 o'clock), calculates the average charging power (25 kWh / 5 hours = 5 kW) from the charging time (5 hours), the battery capacity when fully charged (50 kWh), and the amount of stored energy at the start of charging (25 kWh), and further calculates the adjustment range (5 kW) of the charging power from this average charging power (5 kW) to the minimum charging power (0 kW).

[0171] Based on these calculation results, the adjustment rate command unit 23 instructs the active power command unit 202 to switch the adjustment rate or set a value for the adjustment rate so that a function and / or adjustment rate is applied such that the charging power for a predetermined frequency drop (e.g., a drop from 50Hz to 2Hz) is a predetermined value (e.g., 0kW) (for example, so that control is performed using a moderate adjustment rate of 8% (Figure 13A, Case No. 2)). The phase adjustment command unit 24 also instructs the phase adjustment unit 11 to switch the function or set a value for the coefficient (first-order time constant T) so that a function and / or time constant is applied such that the fluctuation range of the fluctuating power is ±5kW or less in the inertial response simulation (for example, so that phase adjustment is performed using a second function having a large first-order lag time constant T (Figure 13B, Case No. 2)).

[0172] As an example for Case No. 3, let's assume that the charging start time is 0:00, the charging end time is 10:00, the battery capacity when fully charged is 50kWh, the amount of charge at the start of charging is 30kWh, and the maximum charging power of the power converter 3 is 10kW. The charging end time (10:00) is set by the charging end time setting unit 20A. The required charge amount (20kWh) is transmitted, for example, from the electric vehicle (means of transport) 300 to the charge amount measurement unit 21. The average charging power is calculated by the charging power calculation unit 22 based on the required charge amount and charging time. The required charge amount may also be measured or calculated by the charge amount measurement unit 21 using data transmitted from the electric vehicle (means of transport) 300.

[0173] In this case, the charging power calculation unit 22 calculates the charging time (10 hours) from the difference between the charging end time (10:00) and the charging start time (0:00), calculates the average charging power (20kWh / 10 hours = 2kW) from the charging time (10 hours), the battery capacity when fully charged (50kWh), and the amount of stored energy at the start of charging (30kWh), and further calculates the adjustment range (2kW) of the charging power from this average charging power (2kW) to the minimum charging power (0kW).

[0174] Based on these calculation results, the adjustment rate command unit 23 instructs the active power command unit 202 to switch the adjustment rate or set a value for the adjustment rate so that a function and / or adjustment rate is applied such that the charging power for a predetermined frequency drop (for example, a drop from 50 Hz to 48 Hz) is a predetermined value (for example, so that control is performed using a large adjustment rate of 20% (Figure 13A, Case No. 3)). The phase adjustment command unit 24 also instructs the phase adjustment unit 11 to switch the phase so that a function and / or time constant is applied such that the fluctuation range of the fluctuating power is ±2 kW or less in the inertial response simulation (for example, so that phase delay control is performed using a third first-order lag function having a small first-order lag time constant (Figure 13B, Case No. 3)).

[0175] Next, an example of the operation of the power control device 2 according to the first embodiment will be described with reference to the flowchart in Figure 14.

[0176] In the power control device 2, various processes (described later) performed by the charging end time setting unit 20A, the stored energy measurement unit 21, the charging power calculation unit 22, the adjustment rate command unit 23, the phase adjustment command unit 24, and the inertia adjustment command unit 25 determine the function, adjustment rate, time constant, and / or coefficient to be applied in the active power command unit 202 and the phase adjustment unit 11 and / or the inertia simulation control signal generation unit 2i.

[0177] The energy storage amount measurement unit 21 measures or calculates the amount of energy stored in battery B before charging begins, based on a signal transmitted from the battery side (for example, the electric vehicle 300) (step S21). Meanwhile, the charging end time setting unit 20A sets the charging end time for battery B (step S31).

[0178] Next, the charging power calculation unit 22 calculates the charging time from the charging end time (and charging start time) set by the charging end time setting unit 20A (step S32). The charging power calculation unit 22 also calculates the difference (required charge amount) between the amount of charge stored in the battery B at the end of charging (e.g., the battery capacity when fully charged) and the amount of charge stored before charging starts (e.g., the amount of charge measured or calculated by the charge amount measurement unit 21) (step S22). Next, the charging power calculation unit 22 calculates the required charging power (e.g., the average charging power required to fully charge the battery B within the calculated charging time) from the calculated charging time and required charge amount (step S23). Next, it calculates the difference (charging power adjustment range) between the required charging power and the minimum charging power (e.g., 0kW) and / or the maximum charging power (e.g., the rated output of the power converter) (step S24).

[0179] Next, the adjustment rate command unit 23 determines the function and / or adjustment rate to be applied to the active power command unit 202 according to the required charging power and / or charging power adjustment range (step S25). The phase adjustment command unit 24 determines the function, time constant and / or coefficient to be applied to the phase adjustment unit 11 according to the required charging power and / or charging power adjustment range (step S11). The inertia adjustment command unit 25 determines the function and / or coefficient to be applied to the inertia simulation control signal generation unit 2i according to the required charging power and / or charging power adjustment range (step S12).

[0180] For example, if the power adjustment range is narrow, the adjustment rate command unit 23 commands the active power command unit 202 to apply a function and / or adjustment rate with a small power change range (for example, control is performed using a governor-free control function with a large adjustment rate). On the other hand, if the power adjustment range is wide, the adjustment rate command unit 23 commands the active power command unit 202 to apply a function and / or adjustment rate with a large power change range (for example, control is performed using a governor-free control function with a small adjustment rate).

[0181] The active power command unit 202 calculates and outputs an active power command value by performing governor-free control according to the charging power command value (e.g., average charging power) input from the charging power calculation unit 22, the function input from the adjustment rate command unit 23, and / or the adjustment rate and frequency input from the frequency measurement unit 2h. This active power command value output from the active power command unit 202 is reflected in the signal input to the voltage command value calculation unit 2c via the calculation unit 3a, the d-axis current command value calculation unit 3b, and the calculation unit 3c, and affects the processing in the voltage command value calculation unit 2c performed in step S6 described later.

[0182] For example, if the power adjustment range is narrow, the phase adjustment command unit 24 gives a time constant change command to the phase adjustment unit 11 so that a function and / or time constant with a small power change range is applied (for example, so that a first-order lag function with a small time constant is applied to the phase adjustment). On the other hand, if the power adjustment range is wide, the phase adjustment command unit 24 gives a function switching command or a time constant change command to the phase adjustment unit 11 so that a function and / or time constant with a large power change range is applied (for example, so that phase delay control is performed using a first-order lag function with a large time constant). The function and / or time constant affect the processing performed by the phase adjustment unit 11 in step S3, which will be described later.

[0183] Furthermore, for example, if the power adjustment range is narrow, the inertia adjustment command unit 25 provides the inertia simulation control signal generation unit 2i with a coefficient that reduces the range of power change. On the other hand, if the power adjustment range is wide, the inertia adjustment command unit 25 provides the inertia simulation control signal generation unit 2i with a coefficient that increases the range of power change. This coefficient affects the processing performed by the inertia simulation control signal generation unit 2i in step S4, which will be described later.

[0184] Furthermore, in the power control device 2, the grid voltage measurement unit 2a receives a voltage signal supplied from the instrument transformer VT and measures the AC waveform of the grid voltage from this signal (step S1). This grid voltage measurement unit 2a, for example, obtains and outputs a numerical value of the three-phase voltage waveform (sine wave) from the voltage signal supplied from the instrument transformer VT.

[0185] Next, the phase calculation unit 2b determines the phase of the AC waveform of the voltage measured by the grid voltage measurement unit 2a (step S2). This phase calculation unit 2b, for example, converts the three-phase voltage waveform of the voltage from three-phase to two-phase, determines the phase value, and outputs it. Meanwhile, the frequency measurement unit 2h determines the frequency from the output of the grid voltage measurement unit 2a (step S33) and outputs it to the active power command unit 202. Furthermore, the active power command unit 202 receives signals from the charging power calculation unit 22, the adjustment rate switching command unit 23, and the frequency measurement unit (frequency measurement means) 2h, determines the active power command value from these signals (step S26), and outputs it to the calculation unit 3a.

[0186] Next, the phase adjustment unit 11 adjusts the phase of the voltage obtained by the phase calculation unit 2b (step S3). The phase adjustment unit 11, for example, obtains and outputs a value obtained by applying a first-order lag calculation of angular velocity to the phase adjustment (for example, a phase adjusted using a value obtained by multiplying the difference between the angular velocity value of the output of the phase calculation unit 2b and the first-order lag value of angular velocity by a coefficient as needed).

[0187] Next, the inertia simulation control signal generation unit 2i generates an inertia simulation control signal using the phase adjusted by the phase adjustment unit 11, the output of the phase calculation unit 2b (phase before adjustment), and the output of the inertia adjustment control unit 25 (step S4). An example of an inertia simulation control signal is shown below.

[0188] θ: Output of phase calculation unit 2b θlag: Output of phase adjustment unit 11 K: Output of inertia adjustment unit 25 Inertia simulation control signal = K·sin(θ-θlag) In the example above, the larger the value of θ-θlag (but less than or equal to 90°) and the larger the value of K, the greater the degree of inertia simulation. In other words, if the power adjustment range is narrow and the degree of inertia simulation is small, the time constant and / or K of the phase adjustment unit 11 should be set small. If the power adjustment range is wide and the degree of inertia simulation is large, the time constant and / or K of the phase adjustment unit 11 should be set large.

[0189] Next, the output of the active power command unit 202 and the inertia simulation control signal are added together, for example, in the calculation unit 3a (step S5), and input to the d-axis current command value calculation unit 3b.

[0190] Next, the voltage command value calculation unit 2c calculates and outputs a voltage command value from the d-axis current deviation and q-axis current deviation calculated by the calculation units 3c and 3f (step S6).

[0191] The d-axis current deviation and q-axis current deviation used by the voltage command value calculation unit 2c are generated by performing calculations and other processing in the power converter current measurement unit 2f, power converter current dq conversion unit 2g, calculation unit 3a, d-axis current command value calculation unit 3b, calculation unit 3c, calculation unit 3d, q-axis current command value calculation unit 3e, and calculation unit 3f, based on the active power measurement value and reactive power sent from the active power and reactive power calculation unit 201, the active power command value sent from the active power command unit 202, the reactive power command value sent from the reactive power command unit 203, and the current signal sent from the current transformer CT1.

[0192] Next, the two-phase to three-phase conversion unit 2d generates an AC waveform of the voltage command value obtained by the voltage command value calculation unit 2c by converting the voltage command value between two phases and three phases (step S7). This two-phase to three-phase conversion unit 2d, for example, converts the voltage command value obtained by the voltage command value calculation unit 2c into a command value for a three-phase voltage waveform and outputs it (for example, it calculates and outputs values ​​obtained by converting the α-axis voltage command value and the β-axis voltage command value into three-phase AC).

[0193] The command values ​​of the three-phase AC generated by the two-phase to three-phase conversion unit 2d are sent to the U-phase signal generation unit 5A, the V-phase signal generation unit 5B, and the W-phase signal generation unit 5C, respectively, to generate signals for the U-phase, V-phase, and W-phase. These signals are then supplied to the power converter 1, and the input and output of the power converter 1 are controlled.

[0194] As a result, for example, when the power converter 3 is charging, if the grid frequency decreases, the power converter 1 will reduce the charging power to suppress the decrease in grid frequency. On the other hand, if the grid frequency increases, the power converter 1 will increase the charging power to suppress the increase in grid frequency.

[0195] Furthermore, if the power converter 3 is capable of bidirectional operation of charging and discharging, when discharging occurs, if the grid frequency decreases, the power converter 1 will increase the discharge power to suppress the decrease in grid frequency. Conversely, if the grid frequency increases, the power converter 1 will decrease the discharge power to suppress the increase in grid frequency.

[0196] Although Figure 14 shows an example where both active power control by a regulated rate and active power control by inertia simulation are performed, it is also possible to perform only one of either active power control by inertia simulation or active power control by a regulated rate.

[0197] According to the first embodiment, since equipment that does not contribute to frequency adjustment during normal operation can be used for frequency adjustment, it becomes possible to suppress frequency fluctuations in AC electrical circuits such as power systems S. Furthermore, since equipment that does not contribute to frequency stabilization during normal operation can be used for inertia simulation control, it becomes possible to suppress transient frequency fluctuations in AC electrical circuits such as power systems S and contribute to frequency stabilization. In addition, since the effect of frequency adjustment of the electrical circuit and / or the effect of inertia simulation can be adjusted according to the charging power of the battery B, it is possible to contribute to suppressing frequency fluctuations in the electrical circuit without hindering the charging of the battery B.

[0198] [Second Embodiment] Next, a second embodiment will be described. In the following, the explanation of parts common to the first embodiment will be omitted, and the focus will be on the differences.

[0199] Figure 15 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the second embodiment.

[0200] In the first embodiment described above, an example was shown in which a charging completion time setting unit 20A is provided within the power control device 2. In this second embodiment, an example is shown in which a charging time setting unit 20B is provided instead.

[0201] The charging time setting unit 20B sets the charging time for the storage battery B. The charging time can be set by transmitting data to the charging time setting unit 20B via communication from outside the power control device 2 (for example, from an electric vehicle 300), or by directly inputting data to the charging time setting unit 20B.

[0202] The charging power calculation unit 22 calculates the required charging power (for example, the average charging power required to fully charge battery B within the set charging time) from the charging time of battery B set by the charging time setting unit 20B, the amount of charge stored at the end of charging of battery B (for example, the storage capacity when fully charged), and the amount of charge measured or calculated by the storage amount measurement unit 21 (required charge amount), and then calculates the adjustment range of power from the required charging power to the minimum charging power and / or maximum charging power.

[0203] The functions of the other various components are as described in the first embodiment.

[0204] Next, an example of the operation of the power control device 2 according to the second embodiment will be described with reference to the flowchart in Figure 16. In the following, the explanation of parts common to the first embodiment will be omitted, and the explanation will focus on the differences.

[0205] The energy storage amount measurement unit 21 measures or calculates the amount of energy stored in battery B before charging begins, based on a signal transmitted from the battery side (for example, the electric vehicle 300) (step S21). Meanwhile, the charging time setting unit 20B sets the charging time for battery B (step S31-1).

[0206] Next, the charging power calculation unit 22 determines the difference (required charge amount) between the amount of charge stored in the battery B at the end of charging (e.g., the storage capacity when fully charged) and the amount of charge stored before charging begins (e.g., the amount of charge measured or calculated by the storage amount measurement unit 21) (step S22). Next, the charging power calculation unit 22 determines the required charging power (e.g., the average charging power required to fully charge the battery B within the set charging time) from the charging time set by the charging time setting unit 20B and the determined required charge amount (step S23-1). Next, the charging power calculation unit 22 determines the difference (charging power adjustment range) between the required charging power and the minimum charging power (e.g., 0kW) and / or the maximum charging power (e.g., the rated output of the power converter) (step S24).

[0207] Examples of specific processes in steps other than steps S31-1 and S23-1 are as described in the first embodiment.

[0208] According to the second embodiment, by providing a charging time setting unit 20B in the power control device 2 instead of a charging end time setting unit 20A, the need to calculate the charging time is eliminated.

[0209] [Third Embodiment] Next, a third embodiment will be described. In the following, the explanation of parts common to the first embodiment will be omitted, and the focus will be on the differences.

[0210] Figure 17 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the third embodiment.

[0211] In this third embodiment, an example is shown in which the power control device 2 is further equipped with a planned driving distance setting unit (planned driving distance setting means) 31 and a storage target value setting unit (storage target value setting means) 32. Note that the planned driving distance setting unit 31 is not necessarily required and may be omitted.

[0212] In the first and second embodiments described above, examples were shown in which the "storage capacity when fully charged" of the storage battery B is used in the calculation of the charging power calculation unit 22. In this third embodiment, an example is shown in which the "target storage amount value at the end of charging" of the storage battery B is used.

[0213] The planned driving distance setting unit 31 sets the planned driving distance of the electric vehicle (means of transportation) 300 equipped with a storage battery B. The planned driving distance may be set by transmitting data to the planned driving distance setting unit 31 via communication from outside the power control device 2 (for example, the electric vehicle 300), or by directly inputting data to the planned driving distance setting unit 31.

[0214] The energy storage target value setting unit 32 calculates the target energy storage amount at the end of charging from the planned driving distance set by the planned driving distance setting unit 31 and outputs the said energy storage amount target value to the charging power calculation unit 22.

[0215] If the planned driving distance setting unit 31 is not installed, the setting of the energy storage target value may be achieved, for example, by transmitting data to the energy storage target value setting unit 32 via communication from outside the power control device 2 (for example, an electric vehicle 300), or by directly inputting data to the energy storage target value setting unit 32.

[0216] The charging power calculation unit 22 calculates the charging time of the battery B from the charging end time (and charging start time) set by the charging end time setting unit 20A. From the calculated charging time and the difference between the target amount of stored energy (amount of stored energy at the end of charging) calculated by the energy storage target value setting unit 32 and the amount of stored energy measured or calculated by the energy storage amount measurement unit 21 (required charge amount), it calculates the required charging power (for example, the average charging power required to charge the required amount of energy to the battery B within the calculated charging time). It then calculates the adjustment range of power from the required charging power to the minimum charging power and / or maximum charging power. Alternatively, the energy storage target value setting unit 32 may set the required charge amount instead of the target amount of stored energy (amount of stored energy at the end of charging), and the calculation of the required charge amount may be omitted.

[0217] The functions of the other various components are as described in the first and second embodiments.

[0218] Next, an example of the operation of the power control device 2 according to the third embodiment will be described with reference to the flowchart in Figure 18. In the following, the explanation of parts common to the first embodiment will be omitted, and the explanation will focus on the differences.

[0219] The charge level measurement unit 21 measures or calculates the amount of charge stored in battery B before charging begins, based on a signal transmitted from the battery side (for example, the electric vehicle 300) (step S21). Meanwhile, the charging end time setting unit 20A sets the charging end time for battery B (step S31). In addition, the planned driving distance setting unit 31 sets the planned driving distance for the electric vehicle (means of transport) 300 equipped with battery B (step S41).

[0220] Next, the energy storage target value setting unit 32 calculates the energy storage target value from the planned driving distance set by the planned driving distance setting unit 31 and outputs the energy storage target value to the charging power calculation unit 22 (step S42).

[0221] Note that the process in step S41 described above is optional. In that case, the energy storage target value setting unit 32 does not determine the energy storage target value using the planned driving distance, but instead outputs the transmitted or inputted energy storage target value.

[0222] Next, the charging power calculation unit 22 determines the charging time from the charging end time (and charging start time) set by the charging end time setting unit 20A (step S32). The charging power calculation unit 22 also determines the difference (required charge amount) between the target charge amount determined by the charge target value setting unit 32 and the charge amount measured or calculated by the charge amount measurement unit 21 (step S43). Next, the charging power calculation unit 22 determines the required charging power (for example, the average charging power required to fully charge battery B within the calculated charging time) from the determined charging time and required charge amount (step S23). Next, it determines the difference (charging power adjustment range) between the required charging power and the minimum charging power and / or maximum charging power (step S24).

[0223] Examples of specific processes in steps other than steps S41, S42, and S43 are as described in the first embodiment.

[0224] According to the third embodiment, by further providing a power storage target value setting unit 32 within the power control device 2, it becomes possible to determine the required charging power (for example, the average charging power required to charge the required amount of charge to the battery B within the determined charging time) using the power storage target value. Furthermore, by further providing a driving distance setting unit 31, it becomes possible to determine the power storage target value from the driving distance.

[0225] [Fourth Embodiment] Next, a fourth embodiment will be described. In the following, the explanation of parts common to the second embodiment will be omitted, and the focus will be on the differences.

[0226] Figure 19 is a conceptual diagram showing an example of the configuration of a charging equipment having a power converter according to the fourth embodiment.

[0227] In this fourth embodiment, an example is shown in which a planned driving distance setting unit 31 and a storage target value setting unit 32 are further provided within the power control device 2. Note that the planned driving distance setting unit 31 is not necessarily required and may be omitted.

[0228] The planned driving distance setting unit 31 sets the planned driving distance of the electric vehicle (means of transportation) 300 equipped with a storage battery B. The planned driving distance may be set by transmitting data to the planned driving distance setting unit 31 via communication from outside the power control device 2 (for example, the electric vehicle 300), or by directly inputting data to the planned driving distance setting unit 31.

[0229] The energy storage target value setting unit 32 calculates the energy storage amount target value from the planned driving distance set by the planned driving distance setting unit 31 and sets the energy storage amount target value.

[0230] If the planned driving distance setting unit 31 is not installed, the energy storage target value setting unit 32 sets the energy storage target value without using the planned driving distance. The setting of the energy storage target value may be achieved, for example, by transmitting data to the energy storage target value setting unit 32 via communication from outside the power control device 2 (for example, an electric vehicle 300), or by directly inputting data to the energy storage target value setting unit 32.

[0231] The charging power calculation unit 22 calculates the required charging power (for example, the average charging power required to charge the required amount of charge to battery B within the calculated charging time) from the charging time set by the charging time setting unit 20B, the difference between the target amount of charge calculated by the energy storage target value setting unit 32 (amount of charge at the end of charging), and the amount of charge measured or calculated by the energy storage amount measurement unit 21 (required charge amount), and then calculates the adjustment range of power from the required charging power to the minimum charging power and / or maximum charging power. Alternatively, the energy storage target value setting unit 32 may set the required charge amount instead of the target amount of charge (amount of charge at the end of charging), and the calculation of the required charge amount may be omitted.

[0232] The functions of the other various components are as described in the first to third embodiments.

[0233] Next, an example of the operation of the power control device 2 according to the fourth embodiment will be described with reference to the flowchart in Figure 20.

[0234] The charge level measurement unit 21 measures or calculates the amount of charge stored in battery B before charging begins, based on a signal transmitted from the battery side (for example, the electric vehicle 300) (step S21). Meanwhile, the charging time setting unit 20B sets the charging time for battery B (step S31-1). The planned driving distance setting unit 31 sets the planned driving distance for the electric vehicle (means of transport) 300 equipped with battery B (step S41).

[0235] Next, the energy storage target value setting unit 32 calculates the energy storage target value from the planned driving distance set by the planned driving distance setting unit 31 and outputs the energy storage target value to the charging power calculation unit 22 (step S42).

[0236] Note that the process in step S41 described above is optional. In that case, the energy storage target value setting unit 32 does not determine the energy storage target value using the planned driving distance, but instead outputs the transmitted or inputted energy storage target value.

[0237] Next, the charging power calculation unit 22 determines the difference (required charge amount) between the target charge amount value obtained by the charge target value setting unit 32 and the charge amount measured or calculated by the charge amount measurement unit 21 (step S43). Next, the charging power calculation unit 22 determines the required charging power (for example, the average charging power required to fully charge battery B within the set charging time) from the charging time set by the charging time setting unit 20B and the determined required charge amount (step 23-1). Next, the difference (charging power adjustment range) between the required charging power and the minimum charging power and / or maximum charging power is determined (step S24).

[0238] Examples of specific processes in steps other than steps S41, S42, S43, and S23-1 are as described in the second embodiment.

[0239] According to the fourth embodiment, by further providing a power storage target value setting unit 32 within the power control device 2, it becomes possible to determine the required charging power (for example, the average charging power required to charge the required amount of charge to the battery B within the determined charging time) using the power storage target value. Furthermore, by further providing a driving distance setting unit 31, it becomes possible to determine the power storage target value from the driving distance.

[0240] As detailed above, each embodiment makes it possible to change the output and / or input of the equipment in response to transient frequency fluctuations in the system, thereby suppressing frequency fluctuations in the system. [Explanation of Symbols]

[0241] 1...Power converter (charging means), 2...Power control device, 3...Power conversion device, 2a...System voltage measurement unit, 2b...Phase calculation unit (phase calculation means), 2c...Voltage command value calculation unit, 2d...Two-phase three-phase conversion unit, 2f...Power converter current measurement unit, 2g...Power converter current dq conversion unit, 2h...Frequency measurement unit (frequency measurement means), 2i...Inertia simulation control signal generation unit (inertia simulation control signal generation means), 3a...Calculation unit, 3b ...d-axis current command value calculation unit, 3c...calculation unit, 3d...calculation unit, 3e...q-axis current command value calculation unit, 3f...calculation unit, 3g...voltage command value calculation unit, 5A...U-phase signal generation unit, 5B...V-phase signal generation unit, 5C...W-phase signal generation unit, 11...phase adjustment unit (phase adjustment means), 20A...charging end time setting unit (charging end time setting means), 20B...charging time setting unit (charging time setting means), 21...energy storage amount measurement unit (energy storage amount 22...Acquisition means), 23...Charging power calculation unit (charging power calculation means), 24...Adjustment rate command unit (command means), 25...Inertia adjustment command unit (command means), 31...Driving distance setting unit (driving distance setting means), 32...Energy storage target value setting unit (energy storage target value setting means), 201...Active power, reactive power calculation unit, 202...Active power command unit (active power command means), 203...Reactive Power command unit, 300... Electric vehicle (means of transportation), 302... Charging power command unit, B... Storage battery (means of energy storage), CB... Parallel circuit breaker, CT, CT1... Current transformer, R1, R2, R3, F1, F2, F... Function calculation unit, L1... Limit value calculation unit, P1... Limit value priority calculation unit, M... Main transformer, S... Power system, SW1, SW2, SW3, SWa, SWb, SWc, SWd... Switching unit, VT... Instrument transformer.

Claims

1. A power control device that controls a power converter connected to an AC electrical circuit and also connected to a power storage means, A means for obtaining the amount of energy stored in the energy storage means, A phase calculation means for calculating the phase of various electrical quantities in the aforementioned electrical circuit, An inertia simulation control signal generation means that generates an inertia simulation control signal for the power converter according to the measured phase, A command means that, at least according to the amount of stored energy, switches between a plurality of functions stored in the inertia simulation control signal generation means or changes the coefficients of the functions, A power control device equipped with the following.

2. The system further comprises a charging power calculation means that calculates at least one of the required charging power and power adjustment range necessary for charging the energy storage means, using the energy storage capacity of the energy storage means when fully charged and the amount of energy stored. The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

3. A power storage target value setting means for setting a target value for the amount of power stored in the power storage means, A charging power calculation means that uses the aforementioned target value of stored energy and the amount of stored energy to calculate at least one of the required charging power and power adjustment range of the energy storage means. It further comprises, The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

4. A charging completion time setting means for setting the charging completion time of the power storage means, A charging power calculation means that uses the charging completion time and the amount of stored energy to calculate at least one of the required charging power and power adjustment range of the energy storage means. It further comprises, The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

5. A charging time setting means for setting the charging time of the aforementioned power storage means, A charging power calculation means that uses the charging time and the amount of stored energy to calculate at least one of the required charging power and power adjustment range of the energy storage means. It further comprises, The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

6. A charging completion time setting means for setting the charging completion time of the power storage means, A power storage target value setting means for setting a target value for the amount of power stored in the power storage means, A charging power calculation means that uses the charging completion time, the target value of the stored energy, and the stored energy to calculate at least one of the required charging power and power adjustment range of the energy storage means. It further comprises, The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

7. A charging time setting means for setting the charging time of the aforementioned power storage means, A power storage target value setting means for setting a target value for the amount of power stored in the power storage means, A charging power calculation means that uses the charging time, the target value of the stored energy, and the stored energy to calculate at least one of the required charging power and the power adjustment range of the energy storage means. It further comprises, The command means switches between the plurality of functions or changes the coefficients of the functions according to at least one of the required charging power and the power adjustment range. The power control device according to claim 1.

8. The means of transport equipped with the aforementioned power storage means is further provided with a means for setting the planned distance to travel, The energy storage target value setting means calculates the energy storage amount target value from the planned driving distance. The power control device according to claim 3.

9. Each of the aforementioned functions has a different effect on at least one of the frequency adjustment and inertial response simulation of the electrical circuit. The power control device according to claim 1.

10. The command means is The means includes a means for changing the rate at which at least one of the charging power and discharging power of the power converter changes in response to a change in the frequency of the electrical circuit, The power control device according to claim 1.

11. The command means is The means includes a means for changing the amount of simulation of the inertial response of the power converter in response to the phase change of the electrical circuit, The power control device according to claim 1.

12. A power conversion device comprising the power control device and the power converter described in claim 1.

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