Power conversion device control device and power conversion device

Abstract

A power conversion device control device comprising: an effective power calculation section that acquires an electric current value and a voltage value measured on an AC side of a power conversion device, and calculates an effective power value, which is a measurement value for the effective power output by the power conversion device, on the basis of the acquired electric current value and voltage value; an integration unit that acquires the effective power value from the effective power value calculation section and, only when the acquired effective power value is in a charging direction, integrates the effective power value to calculate a charging power; a gain unit that calculates a first control value obtained by multiplying the charging power integrated by the integration unit and a prescribed gain; a DC voltage determination section that acquires the first control value calculated by the gain unit, calculates a DC voltage value from the charging power on the basis of the acquired first control value, and determines whether the calculated DC voltage value is at or above a prescribed threshold value; and an addition unit that, when it is determined by the DC voltage determination section that the DC voltage value is at or above the prescribed threshold value, adds together a prescribed effective power command value and the first control value and implements P droop control.

Description

Control device for power conversion device and power conversion device

[0001] The present invention relates to a control device for a power conversion device and a power conversion device.

[0002] Conventionally, power conversion devices perform feedforward control based on a grid voltage. However, with normal feedforward control, it is difficult to deal with a sudden and abnormal increase in output voltage that occurs in an abnormal situation, such as when the power conversion device is suddenly disconnected from the power grid. In this regard, a power conversion device that has been improved to suppress an abnormal increase in output voltage is known (see, for example, Patent Document 1).

[0003] Japanese Patent No. 6973657

[0004] In the power conversion device described above, for example, when operation is started, operation is performed under the control of a DC-AVR (Direct Current-Automatic Voltage Regulator). When operation under the control of the DC-AVR (hereinafter simply referred to as "DC-AVR") is performed, the DC voltage is controlled to be maintained at a predetermined value, and the DC voltage can be stabilized at the predetermined value.

[0005] However, in the existing control, for example, when the active power command value is a 0% command and a negative offset is applied to the detection system during DC-AVR, the power conversion device performs charging operation, which may cause unstable voltage control. In other words, in such a case, there is a problem that the control of the DC-AVR becomes unstable, which may cause DC overvoltage.

[0006] Therefore, an object of the present disclosure is to suppress instability in voltage control by introducing P droop control into a power conversion device.

[0007] A control device for a power conversion device according to one embodiment includes: an active power calculation unit that acquires a current value and a voltage value measured on the AC side of the power conversion device and calculates an active power value, which is a measurement value of the active power being output by the power conversion device, based on the acquired current value and voltage value; an integrator that acquires the active power value from the active power calculation unit and calculates charging power by integrating the active power value only when the acquired active power value is in the charging direction; a gain unit that calculates a first control value by multiplying the charging power integrated by the integrator by a predetermined gain; a DC voltage determination unit that acquires the first control value calculated by the gain unit, calculates a DC voltage value from the charging power based on the acquired first control value, and determines whether the calculated DC voltage value is equal to or greater than a predetermined threshold; and an adder that performs P droop control by adding a predetermined active power command value and the first control value when the DC voltage determination unit determines that the DC voltage value is equal to or greater than the predetermined threshold.

[0008] A power conversion device according to one aspect includes an inverter that converts DC power into AC power, and the control device described above.

[0009] According to the present disclosure, by introducing P droop control into a power conversion device, it is possible to prevent voltage control from becoming unstable when the active power command value takes a value of 0% and a negative offset is introduced into the detection system.

[0010] 2 is a diagram showing an example of the configuration of a control device for a power conversion device and a power conversion device according to an embodiment. It is a diagram showing an example of the control configuration and processing of P droop control performed in a power control unit of the control device shown in Fig. 1. It is a conceptual diagram showing an example of the hardware configuration of a processing circuit included in the control device in the embodiment shown in Figs.

[0011] Hereinafter, embodiments of a control device for a power conversion device and a power conversion device according to the present disclosure will be described with reference to the drawings.

[0012] 1 is a diagram showing an example of the configuration of a control device 30 of a power conversion device 1 according to one embodiment and the power conversion device 1. In Fig. 1, the power conversion device 1 is connected to a DC power source 4 via a DC bus 2 at one end (input side) on the left side in Fig. 1, and connected to an AC power system 5 via an AC circuit 3 at the other end (output side) on the right side in Fig. 1.

[0013] The power conversion device 1 converts, for example, DC power supplied from a DC power source 4 (DC side) into AC power and outputs the converted AC power to an AC power system 5 (AC side). The power conversion device is also called a "PCS (Power Conditioning System)" or a "power conditioner."

[0014] The power conversion device 1 in this embodiment will be described as a power conversion device for photovoltaics (PV) power generation (Photovoltaics-Power Conditioning System (PV-PCS)). However, the power conversion device 1 may also be, for example, a power conversion device for a binary power generation system.

[0015] 1 , the power conversion device 1 includes a DC switch 11, a DC capacitor 12, an inverter 13, an AC reactor 14, an AC capacitor 15, and an AC switch 16. The power conversion device 1 also includes a first current sensor 21, a first voltage sensor 22, a second current sensor 23, a second voltage sensor 24, a third current sensor 25, and a control device 30. Note that the control device 30 is electrically connected to each element of the power conversion device 1, although wiring is omitted in the figure.

[0016] The DC bus 2 connects the DC power source 4 and a DC end (input side) of the inverter 13 in the power conversion device 1. The DC bus 2 has a positive bus and a negative bus, and supplies DC power supplied from the DC power source 4 to the inverter 13. On the DC bus 2, for example, a first current sensor 21, a DC switch 11, a first voltage sensor 22, and a DC capacitor 12 are arranged in this order from the DC power source 4 toward the DC end of the inverter 13.

[0017] The AC circuit 3 connects the AC end (output side) of the inverter 13 in the power conversion device 1 to the AC power system 5. The AC circuit 3 is, for example, a three-phase, three-wire three-phase AC circuit that supplies three-phase AC power, which is a combination of three systems of single-phase AC with mutually shifted phases of current or voltage, using three electric wires, cables, and conductors. The AC circuit 3 supplies the AC power converted by the inverter 13 to the AC power system 5. The AC circuit 3 includes, for example, a second current sensor 23, an AC reactor 14, an AC capacitor 15, an AC switch 16, a second voltage sensor 24, and a third current sensor 25 arranged in this order from the AC end of the inverter 13 toward the AC power system 5.

[0018] The DC power supply 4 is connected to the DC end (input end) of the inverter 13 via the DC bus 2. In this embodiment, the DC power supply 4 is described as a solar panel (solar cell panel, PV panel), but it may also be, for example, a binary generator. The DC power supply 4 supplies DC power (generated by, for example, a solar panel) to the inverter 13 via the DC bus 2.

[0019] The AC power system (system) 5 is connected to the AC end (output end) of the inverter 13 via the AC circuit 3. The AC power system 5 is connected to a transformer (not shown) and is a system that integrates power generation, power transformation, power transmission, and power distribution in order to supply AC power transformed by the transformer (not shown) to power receiving equipment of consumers, and is connected to, for example, an unspecified load. Hereinafter, in the present specification and drawings, the AC power system 5 will also be simply referred to as the "power system 5" or "system 5." Note that the AC power system 5 may be a power system or, for example, an electric motor, a generator, or other AC load.

[0020] The DC switch (DC circuit breaker) 11 is provided in series on the DC bus 2 between the first current sensor 21 and the first voltage sensor 22. The DC switch 11 makes (connects) or opens (disconnects) the DC bus 2 between the DC power source 4 and the inverter 13 in accordance with, for example, an on command or an off command from the control device 30 or an operator (not shown). When the DC switch 11 is opened, the DC power supplied from the DC power source 4 to the inverter 13 is cut off. Hereinafter, in this specification and drawings, the DC switch 11 is also referred to as a "DC (Direct Current) switch 11."

[0021] The DC capacitor 12 is provided on the DC bus 2 between the first voltage sensor 22 and the DC end of the inverter 13. The DC capacitor 12 is a smoothing capacitor that smoothes the DC voltage output from the DC power supply 4. For example, when the DC switch 11 is closed, the DC capacitor 12 is charged with DC power from the DC power supply 4, causing the voltage to increase, and when the DC switch 11 is open, the DC capacitor 12 is discharged, for example, by a discharge circuit or discharge resistor (not shown), causing the voltage to decrease. Hereinafter, in this specification and drawings, the DC capacitor 12 will also be referred to as the "DC capacitor 12."

[0022] One end of the inverter (inverter circuit) 13, which is a DC end, is connected to the DC capacitor 12 and the DC switch 11 via the DC bus 2, and the other end, which is an AC end, is connected to the AC reactor 14 via the AC circuit 3. The inverter 13 is configured with a plurality of switching elements such as IGBTs (Insulated Gate Bipolar Transistors). The inverter 13 is controlled by, for example, a pulse width modulation (PWM) signal, which is a gate drive signal (gate signal G) for the switching elements, generated by a pulse width modulation (PWM) control unit 58 described below.

[0023] The inverter 13 acquires DC power supplied from the DC power supply 4 from one end thereof, and converts the acquired DC power into AC power under control of a pulse width modulation signal (gate signal G), and outputs the AC power from the other end thereof, which is an output end, to be supplied to the grid 5. In the following description and drawings, the inverter 13 is also referred to as the "inverter circuit 13," and the pulse width modulation signal is also referred to as the "PWM signal."

[0024] The AC reactor 14 is connected in series with the AC end of the inverter 13 in the AC circuit 3. The AC reactor 14 is a smoothing element that has, for example, the effect of reducing noise and suppressing surge voltage. The AC reactor 14, together with an AC capacitor 15 connected in an L-shape via a branch point 15a, constitutes, for example, an LC filter circuit that reduces ripples (vibrations) that occur when a switching element (not shown) of the inverter 13 switches on and off. Hereinafter, in this specification and drawings, the AC reactor 14 is also referred to as an "AC (Alternating Current) reactor 14."

[0025] The AC capacitor 15 is an electronic component that stores or releases electricity (charge), and is connected in an L-type configuration with the AC reactor 14 via a branch point 15a in the AC circuit 3. The AC capacitor 15, together with the AC reactor 14 connected in an L-type configuration, constitutes, for example, an LC filter circuit that reduces ripples generated when a switching element (not shown) of the inverter 13 switches on and off. The AC capacitor 15, together with the AC reactor 14, constitutes a filter circuit, thereby suppressing the outflow of harmonics (harmonic currents) to the grid 5. Hereinafter, in this specification and drawings, the AC capacitor 15 will also be referred to as the "AC capacitor 15."

[0026] The AC switch (AC circuit breaker) 16 is provided in series between the AC reactor and AC capacitor and the grid 5 in the AC circuit 3. The AC switch 16 turns on (connects) or opens (disconnects) the AC circuit 3 between the inverter 13 and the grid 5 in accordance with, for example, a turn-on instruction or an open instruction from the control device 30 or an operator (not shown). When the AC switch 16 is opened, the AC power supplied from the inverter 13 to the grid 5 is cut off. Hereinafter, in this specification and drawings, the AC switch 16 is also referred to as an "AC switch 16."

[0027] The first current sensor 21 is, for example, a known DC ammeter or DC current sensor, and is disposed between the DC power supply 4 on the DC side and the DC switch 11, and detects the DC current I ＤＣ The position where the first current sensor 21 is disposed is not limited to the position shown in FIG. 1 , and the value of the DC current I ＤＣ Any position where the value of DC current I can be detected is acceptable. ＤＣ The value of the DC current I ＤＣ ", or simply "DC current I ＤＣ The DC current I detected by the first current sensor 21 is also referred to as ＤＣ is acquired by the control device 30.

[0028] The first voltage sensor 22 is, for example, a known DC voltmeter or DC voltage sensor, and is disposed between the DC switch 11 and the DC capacitor 12 on the DC side, and detects the DC voltage V of the DC power supply 4. ＤＣ The position where the first voltage sensor 22 is disposed is not limited to the position shown in FIG. 1 , and the value of the DC voltage V ＤＣ Any position where the value of DC voltage V can be detected is acceptable. ＤＣ The value of "DC voltage value V ＤＣ ", or simply "DC voltage V ＤＣ The DC voltage V detected by the first voltage sensor 22 is also referred to as ＤＣ is acquired by the control device 30.

[0029] The second current sensor 23 is, for example, a known AC ammeter or AC current sensor, and is disposed between the inverter 13 on the AC side and the AC reactor 14, and detects the inverter output current I of the three-phase AC current that is the output current of the inverter 13. ＡＣ The position where the second current sensor 23 is disposed is not limited to the position shown in FIG. 1 , and the value of the inverter output current I ＡＣ Any position where the value of the inverter output current I can be detected is acceptable. ＡＣ The value of "inverter output current value I ＡＣ ", or simply "inverter output current I ＡＣ The inverter output current I detected by the second current sensor 23 is also referred to as " ＡＣ is acquired by the control device 30.

[0030] The second voltage sensor 24 is, for example, a known AC voltmeter or AC voltage sensor, and is disposed between the AC switch 16 on the AC side and the grid 5, and detects the grid voltage V Ｇｒｉｄ The position where the second voltage sensor 24 is disposed is not limited to the position shown in FIG. 1 , and the value of the system voltage V Ｇｒｉｄ Any position where the value of the system voltage V can be detected is acceptable. Ｇｒｉｄ The value of "system voltage value V Ｇｒｉｄ ", or simply "System voltage V Ｇｒｉｄ The system voltage V detected by the second voltage sensor 24 is also referred to as Ｇｒｉｄ is acquired by the control device 30.

[0031] The third current sensor 25 is, for example, a known AC ammeter or AC current sensor, and is disposed between the AC switch 16 on the AC side and the grid 5, and detects the grid current I, which is a three-phase AC current flowing in the grid 5. Ｇｒｉｄ The position where the third current sensor 25 is disposed is not limited to the position shown in FIG. 1 , and the value of the grid current I Ｇｒｉｄ Any position where the value of the grid current I can be detected is acceptable. ＧｒｉｄThe value of "grid current value I Ｇｒｉｄ ", or simply "system current I Ｇｒｉｄ The grid current I detected by the third current sensor 25 is also referred to as Ｇｒｉｄ is acquired by the control device 30.

[0032] The control device 30 is provided, for example, inside or outside the power conversion device 1, and although wiring and the like are omitted in the drawing, it is connected by wire or wirelessly to each component of the power conversion device 1, including the inverter 13. Note that the control device 30 may be realized as a function of an inverter control circuit (not shown).

[0033] The control device 30 includes a processor 91 (see FIG. 3 ), which will be described later, such as a CPU (Central Processing Unit) that operates by executing a program. The control device 30 also includes a storage unit 60 and a memory 92 (see FIG. 3 ), which will be described later, and executes a predetermined program stored in the storage unit 60 or the memory 92 to operate the processor 91, thereby controlling the operation of the power conversion device 1 in an integrated manner.

[0034] The control device 30 may operate, for example, according to instructions from a higher-level device (not shown) or instructions from an operator via an operation unit (not shown). The higher-level device (not shown) comprehensively monitors and controls a plurality of power conversion devices 1, and is connected to each power conversion device 1 by wire or wirelessly. The higher-level device (not shown) is, for example, a main site controller (MSC) or an energy management system (EMS).

[0035] 1 , the control device 30 has the following configurations or functions. That is, the control device 30 functions as a PLL (Phase Locked Loop) control unit 41, a first conversion unit 42, a second conversion unit 43, and a power control unit 44. The control device 30 also functions as an MPPT (Maximum Power Point Tracking) control unit 51, a first subtraction unit 52, and a DC voltage control unit 53. The control device 30 also functions as a first addition unit 54, a third conversion unit 55, a second subtraction unit 56, a current control unit 57, and a PWM control unit 58.

[0036] The above-described configurations or functions may be realized by a program executed by a processor 91 (see FIG. 3) described below in a processing circuit 90 (see FIG. 3) described below included in the control device 30, or by hardware 93 (see FIG. 3) described below. The control device 30 executes a predetermined program and performs the following processes using the functions of the above-described parts.

[0037] The PLL control unit 41 is connected to the second voltage sensor 24, the first conversion unit 42, and the second conversion unit 43. The PLL control unit 41 converts the system voltage V Ｇｒｉｄ The PLL control unit 41 acquires information on the system voltage V Ｇｒｉｄ PLL control is performed based on the system voltage V Ｇｒｉｄ The information on the reference phase θ synchronized with the reference phase θ is output to the first conversion unit 42 and the second conversion unit 43 .

[0038] The first conversion unit 42 is connected to the second voltage sensor 24, the PLL control unit 41, and the power control unit 44. The first conversion unit 42 converts the system voltage V Ｇｒｉｄ and information on the reference phase θ output from the PLL control unit 41. The first conversion unit 42 performs a three-phase to two-phase conversion (dq conversion) based on the acquired reference phase θ, and converts the system voltage V Ｇｒｉｄ is converted into a d-axis voltage value and a q-axis voltage value.

[0039] The second conversion unit 43 is connected to the second current sensor 23, the third current sensor 25, the PLL control unit 41, and the power control unit 44. The second conversion unit 43 converts the inverter output current I ＡＣ and the grid current I Ｇｒｉｄ and information on the reference phase θ output from the PLL control unit 41. The second conversion unit 43 performs three-phase to two-phase conversion (dq conversion) based on the acquired reference phase θ, and converts the inverter output current I ＡＣ and system current I Ｇｒｉｄ and are converted into d-axis current values ​​and q-axis current values.

[0040] The power control unit 44 is connected to the first conversion unit 42, the second conversion unit 43, the first addition unit 54, and the third conversion unit 55. The power control unit 44 obtains information on the d-axis voltage value and the q-axis voltage value from the first conversion unit 42, and obtains information on the d-axis current value and the q-axis current value from the second conversion unit 43. That is, the power control unit 44 obtains the system voltage V Ｇｒｉｄ and obtains the measured value information of the inverter output current I from the second conversion unit 43. ＡＣ and system current I Ｇｒｉｄ Obtain information on the measurement values.

[0041] The power control unit 44 calculates a d-axis current command value I based on the acquired information on the d-axis voltage value, the q-axis voltage value, the d-axis current value, and the q-axis current value. ＊ ｄ and the q-axis current command value I ＊ ｑ That is, the power control unit 44 calculates the obtained system voltage V Ｇｒｉｄ and the inverter output current I ＡＣ and system current I Ｇｒｉｄ Based on the information of the measured values, the d-axis current command value I ＊ ｄ and the q-axis current command value I ＊ ｑ The power control unit 44 calculates the calculated d-axis current command value I ＊ ｄ The information is output to the first adder 54, and the obtained q-axis current command value I ＊ ｑThe information is output to the third conversion unit 55.

[0042] In this embodiment, the power control unit 44 controls the acquired system voltage V Ｇｒｉｄ and the inverter output current I ＡＣ The information on the measured value and the active power command value P ＊ Therefore, in this embodiment, the P droop control is performed based on the d-axis current command value I ＊ ｄ The value of P is a value obtained by executing the P droop control. Details of the P droop control by the power control unit 44 will be described later (see FIG. 2, etc.).

[0043] The MPPT control unit (maximum power point tracking control unit) 51 is connected to the first current sensor 21, the first voltage sensor 22, and the first subtraction unit 52. The MPPT control unit 51 calculates the DC current I ＤＣ and the DC voltage V ＤＣ The MPPT control unit 51 acquires the information of the acquired DC current I ＤＣ Information on DC voltage V ＤＣ Based on this information, for example, MPPT control based on a known hill-climbing method is performed to obtain the DC voltage command value V ＊ ＤＣ The range of MPPT control by the MPPT control unit 51 is determined for each device, for example. The MPPT control unit 51 calculates the calculated DC voltage command value V ＊ ＤＣ The information is output to the first subtraction unit 52.

[0044] The first subtraction unit 52 is connected to the first voltage sensor 22 and the MPPT control unit 51. The first subtraction unit 52 calculates the DC voltage V ＤＣ and the DC voltage command value V output from the MPPT control unit 51. ＊ ＤＣ The first subtraction unit 52 obtains the DC voltage command value V ＊ ＤＣ to DC voltage V ＤＣThe first subtraction unit 52 calculates a value (difference) by subtracting the calculated DC voltage command value V ＊ ＤＣ to DC voltage V ＤＣ The information on the value (difference) obtained by subtracting the above is output to the DC voltage control unit 53.

[0045] The DC voltage control unit 53 is connected to the first subtraction unit 52 and the first addition unit 54. The DC voltage control unit 53 calculates the DC voltage command value V ＊ ＤＣ to DC voltage V ＤＣ The DC voltage control unit 53 controls the acquired information to calculate a d-axis current command value. The DC voltage control unit 53 outputs information on the calculated d-axis current command value to the first adder 54.

[0046] The first adder 54 is connected to the power control unit 44, the DC voltage control unit 53, and the third conversion unit 55. The first adder 54 converts the d-axis current command value I ＊ ｄ and information on the d-axis current command value output from the DC voltage control unit 53. The first adder 54 calculates the d-axis current command value I ＊ ｄ The first adder 54 calculates a value obtained by adding the calculated d-axis current command value I ＊ ｄ and the d-axis current command value are added together, and the information on this sum is output to the third conversion unit 55.

[0047] The third conversion unit 55 is connected to the power control unit 44, the first adder 54, and the second subtractor 56. The third conversion unit 55 converts the q-axis current command value I ＊ ｑ and the d-axis current command value I output from the first adder 54. ＊ ｄ The third conversion unit 55 performs a two-phase to three-phase conversion (inverse dq conversion) on the acquired information to obtain the current command value I ＊ ＡＣ The third conversion unit 55 calculates the calculated current command value I ＊ ＡＣ The information is output to the second subtraction unit 56.

[0048] The second subtraction unit 56 is connected to the second current sensor 23, the third conversion unit 55, and the current control unit 57. The second subtraction unit 56 calculates the inverter output current I ＡＣ and the current command value I output from the third conversion unit 55. ＊ ＡＣ The second subtraction unit 56 obtains the current command value I ＊ ＡＣ to inverter output current I ＡＣ The second subtraction unit 56 calculates a value (difference) by subtracting the calculated current command value I ＊ ＡＣ to inverter output current I ＡＣ The information on the value (difference) obtained by subtracting the above is output to the current control unit 57.

[0049] The current control unit 57 is connected to the second subtraction unit 56 and the PWM control unit 58. The current control unit 57 calculates the current command value I ＊ ＡＣ to inverter output current I ＡＣ The current control unit 57 controls the acquired information to calculate a voltage command value. The current control unit 57 outputs the calculated voltage command value to the PWM control unit 58.

[0050] The PWM control unit (pulse width modulation control unit) 58 is connected to the inverter 13 and the current control unit 57. The PWM control unit 58 acquires a voltage command value from the current control unit 57. The PWM control unit 58 performs PWM control based on the acquired voltage command value and generates a gate signal G, which is a pulse width modulation signal (PWM signal). The PWM control unit 58 outputs the generated gate signal G to the inverter 13 and controls a switching element (not shown) of the inverter 13 to comprehensively control the operation of the inverter 13.

[0051] The storage unit 60 is a volatile or non-volatile storage medium such as a hard disk drive (HDD), a solid state drive (SSD), a dynamic random access memory (DRAM), or other semiconductor memory. The storage unit 60 is connected to each unit of the control device 30 via, for example, a bus (system bus) (not shown) so as to enable input and output of various information. The storage unit 60 stores, for example, programs required for the operation of each unit of the control device 30, and various pieces of information are written to and read from the storage unit 60 by each unit of the control device 30.

[0052] The storage unit 60 also stores, for example, values ​​detected (measured) by each sensor, such as the first current sensor 21. The storage unit 60 also stores, for example, various calculation formulas, coefficients, thresholds, predetermined rated values, limiter values, etc. used in calculations by each unit, such as the power control unit 44 and the MPPT control unit 51. The storage unit 60 also stores, for example, calculation results by each unit, such as the power control unit 44 and the MPPT control unit 51. The storage unit 60 may also store various command values, various operation instructions, etc. acquired from a higher-level device (not shown) or an operator (not shown).

[0053] The storage unit 60 may be provided outside the control device 30 and connected to the control device 30 by wire or wirelessly, and may be an external storage medium such as a memory card or a DVD (Digital Versatile Disc), or may be online storage, etc. The storage unit 60 may also be a memory 92 (see FIG. 3 ) described later.

[0054] Fig. 2 is a diagram showing an example of the control configuration and processing of P droop control performed by the power control unit 44 of the control device 30 shown in Fig. 1. As shown in Fig. 2, the power control unit 44 functions as the following units by executing a predetermined program stored in the storage unit 60 or a memory 92 (see Fig. 3) described below, for example.

[0055] The power control unit 44 functions as an active power calculation unit 71, an integrator 72, a gain unit 73, a limiter 74, a DC voltage determination unit 75, a function activation unit 76, a logical product circuit 77, a selector 78, and an adder 79. The power control unit 44 also functions as a subtractor 81, a feedback control unit 82 (e.g., PI (Proportional-Integral)), a second limiter 83, a feedforward unit 84, and a second adder 85.

[0056] The above-described functions may be realized by a program executed by a processor 91 (see FIG. 3) in a processing circuit 90 (see FIG. 3) included in the control device 30, which will be described later, or by hardware 93 (see FIG. 3) which will be described later. Each of the above-described units executes a predetermined program to perform the following processes.

[0057] The active power calculation unit 71 obtains information on the d-axis voltage value and information on the q-axis voltage value from the first conversion unit 42 (see FIG. 1 ), and obtains information on the d-axis current value and information on the q-axis current value from the second conversion unit 43 (see FIG. 1 ). Ｇｒｉｄ and obtains the measured value information of the inverter output current I from the second conversion unit 43. ＡＣ The active power calculation unit 71 obtains information on the measured value of the system voltage V Ｇｒｉｄ and the inverter output current I ＡＣ Based on the information on the measured values ​​of the active power P and the inverter 13, the active power calculation unit 71 calculates a measured value of the active power P being output by the power conversion device 1 (inverter 13). Hereinafter, in this specification and drawings, the measured value of the active power P will also be referred to as the "active power measured value P," the "active power value P," or simply as the "active power P." The active power calculation unit 71 outputs the calculated active power measured value (active power value) P to the integrator 72 and the subtractor 81.

[0058] The integrator 72 acquires the active power measurement value P from the active power calculation unit 71 and determines whether the acquired active power measurement value P is in the charge direction. If the integrator 72 determines that the acquired active power measurement value P is in the charge direction, it integrates the active power measurement value P to calculate the charge power (amount of energy). The integrator 72 then outputs the calculated charge power to the gain unit 73. On the other hand, if the integrator 72 determines that the acquired active power measurement value P is not in the charge direction (is in the discharge direction), it terminates the process without integrating the active power value P. As a result, the integrator 72 integrates the active power value P only when the active power measurement value P is in the charge direction, and the power control unit 44 can therefore perform P droop control only when the active power measurement value P is in the charge direction.

[0059] The gain unit 73 obtains the charging power from the integrator 72 and also obtains a predetermined gain K. The predetermined gain K is obtained, for example, by executing P droop control to obtain the active power command value P ＊ The predetermined gain K may be set to a value such that the charge power is in the discharging direction rather than the charging direction. The predetermined gain K may be, for example, a value calculated for each charging power, a value stored in the storage unit 60 for each charging power, or a value acquired from a higher-level device (not shown) or an operator (not shown). The gain unit 73 multiplies the acquired charging power by the predetermined gain K to calculate a first control value for P droop control. The gain unit 73 outputs the calculated first control value to the limiter 74 and the DC voltage determination unit 75. Thus, the gain unit 73 multiplies the acquired charging power by the predetermined gain K only when the active power measurement value P is in the charging direction, and therefore the power control unit 44 can execute P droop control only when the active power measurement value P is in the charging direction.

[0060] The limiter 74 acquires the first control value from the gain unit 73 and limits the acquired first control value to a second control value that is a value within a predetermined range. For example, the limiter 74 converts the first control value acquired from the gain unit 73 into an active power command value P ＊is not in the charging direction (negative value) but in the discharging direction (positive value), and the limited value is set as the second control value. Limiter 74 outputs the second control value, which is the value obtained by limiting the first control value, to selector 78. By providing limiter 74, the first control value that performs P droop control in the charging direction (negative direction) is limited (stopped), and thus P droop control can be performed only in the discharging direction (positive direction). Note that by providing limiter 74, the d-axis current command value I ＊ ｄ It is also possible to prevent the value from fluctuating beyond the range limited by the limiter 74.

[0061] For example, the limiter 74 may be a switch that switches whether or not to output the first control value. ＊ is set to a value that causes the direction of discharge rather than the direction of charge, the function of the limiter 74 may be omitted. In this case, the first control value calculated by the gain unit 73 is output to the selector 78.

[0062] The DC voltage determination unit 75 acquires the first control value output from the gain unit 73 and calculates (back-calculates) the DC voltage from the charging power based on the acquired first control value. The DC voltage determination unit 75 then determines whether the calculated DC voltage value is equal to or greater than a predetermined threshold. If the DC voltage determination unit 75 determines that the calculated DC voltage value is equal to or greater than the predetermined threshold, it outputs a "1" (high level) to the AND circuit 77. On the other hand, if the DC voltage determination unit 75 determines that the calculated DC voltage value is not equal to or greater than the predetermined threshold, it outputs a "0" (low level) to the AND circuit 77. This prevents P droop control from being performed excessively due to slight fluctuations between the discharging and charging directions of the active power measurement value P, thereby stabilizing the operation of the inverter 13 (power conversion device 1). In other words, this allows the power control unit 44 to perform P droop control only when a certain level of charging voltage has accumulated, thereby stabilizing the operation of the inverter 13 (power conversion device 1).

[0063] Function enabling unit 76 monitors the operation mode, determines whether MPPT control or DC-AVR is being performed in control device 30, and outputs information on whether the P droop control function should be enabled based on the determination result. When function enabling unit 76 determines that DC-AVR is being performed as a result of monitoring the operation mode of control device 30, it outputs information "1" (high level) indicating that the P droop control function is enabled to logical product circuit 77. On the other hand, when function enabling unit 76 determines that MPPT control is being performed as a result of monitoring the operation mode of control device 30, it outputs information "0" (low level) indicating that the P droop control function is not enabled (disabled) to logical product circuit 77.

[0064] For example, when the power conversion device 1 is a power conversion device 1 for photovoltaic power generation, the MPPT control is performed by the MPPT control unit 51 (see FIG. 1 ) in the power conversion device 1 (control device 30) during normal operation in the daytime based on a known hill-climbing method or the like. According to MPPT control based on a known hill-climbing method or the like, the DC voltage command value V ＊ ＤＣ is constantly updated and constantly fluctuating. For this reason, if the MPPT control unit 51 performs P droop control while MPPT control is being performed, there is a risk that the P droop control will interfere with the MPPT control. On the other hand, when DC-AVR is being performed in the power conversion device 1 (control device 30), the DC voltage command value V ＊ ＤＣ Since is fixed, there is a low risk that the P droop control will interfere with the DC-AVR control.

[0065] Furthermore, for example, if the power conversion device 1 is a power conversion device 1 for photovoltaic power generation, and the power conversion device 1 (control device 30) is not performing MPPT control (e.g., other than daytime), DC-AVR is performed. Furthermore, for example, if the power conversion device 1 is a power conversion device 1 for a binary power generation system or a storage battery, DC-AVR is always performed in the power conversion device 1 (control device 30) when the power conversion device 1 is operating. Therefore, as described in paragraph

[0006] , P droop control is required to stabilize voltage control and suppress DC overvoltage.

[0066] Therefore, when the function enabling unit 76 determines that DC-AVR is being performed in the power conversion device 1 (control device 30), it sets the P droop control function to be enabled, and outputs “1” (high level) to the logical product circuit 77. On the other hand, when the function enabling unit 76 determines that MPPT control is being performed in the power conversion device 1 (control device 30), it sets the P droop control function to be disabled (invalid), and outputs “0” (low level) to the logical product circuit 77.

[0067] This prevents the risk of P droop control interfering with MPPT control due to P droop control being performed when MPPT control is not being performed by MPPT control unit 51. Furthermore, this allows power control unit 44 to perform P droop control to suppress DC overvoltage only when there is a concern as described in paragraph

[0006] while power conversion device 1 is in DC-AVR.

[0068] The logical product circuit 77 acquires information indicating whether the P droop control function is enabled from the function enabler 76. The logical product circuit 77 also acquires information indicating whether the DC voltage value is equal to or greater than a predetermined threshold value from the DC voltage determiner 75.

[0069] Then, when AND circuit 77 acquires information "1" indicating that the P droop control function is enabled and also acquires information "1" indicating that the DC voltage value is equal to or greater than a predetermined threshold, it outputs information "1" (high level) indicating that P droop control should be started to selector 78. That is, AND circuit 77 outputs information "1" (high level) indicating that P droop control should be started to selector 78 only when the information acquired from function enablement unit 76 and the information acquired from DC voltage determination unit 75 are "1" / "1".

[0070] On the other hand, when AND circuit 77 receives at least one of information "0" indicating that the P droop control function is not enabled and information "0" indicating that the DC voltage value is not equal to or greater than the predetermined threshold, it outputs information "0" (low level) indicating that P droop control will not be started to selector 78. In other words, when at least one of the information received from function enablement unit 76 and the information received from DC voltage determination unit 75 is "0", AND circuit 77 outputs information "0" (low level) indicating that P droop control will not be started to selector 78.

[0071] This makes it possible to restrict the P droop control from being performed solely due to small fluctuations between the discharge direction and charge direction of the active power measurement value P. This also makes it possible to prevent the P droop control from interfering with the MPPT control, and since the power conversion device 1 suppresses DC overvoltage while in DC-AVR, the power control unit 44 can perform the P droop control.

[0072] Selector 78 obtains the second control value from limiter 74. When the function of limiter 74 is omitted from power control unit 44, selector 78 obtains the first control value from gain unit 73. Selector 78 also obtains the value of "0.0" (control value) from, for example, storage unit 60. Furthermore, selector 78 obtains information from AND circuit 77 as to whether P droop control should be started.

[0073] When selector 78 receives from AND circuit 77 information "1" indicating that P droop control should be started, selector 78 selects the second control value received from limiter 74 (or the first control value received from gain unit 73) and outputs it to adder 79. On the other hand, when selector 78 receives from AND circuit 77 information "0" indicating that P droop control should not be started, selects the control value "0.0" received from storage unit 60, for example, and outputs it to adder 79.

[0074] As a result, when the P droop control function is disabled, for example, during MPPT control, a control value of "0.0" is selected and output to the adder 79, thereby preventing the P droop control from affecting subsequent control.

[0075] The adder 79 receives a predetermined active power command value P from a higher-level device (not shown), such as an MSC or EMS. ＊ The predetermined active power command value P ＊ may be, for example, a value calculated based on a predetermined calculation or a predetermined simulation result, a value stored in the storage unit 60, or a value received from an operator (not shown) via an operation unit (not shown). The adder 79 acquires the second control value (or the first control value) output from the selector 78, or the control value of "0.0". The adder 79 then calculates the active power command value P ＊ and the value obtained from the selector 78 (the second control value (or the first control value), or the control value of "0.0"), and executes P droop control. Then, the adder 79 outputs the P droop control value, which is the value obtained by executing the P droop control, to the subtractor 81 and the feedforward unit 84. By executing the P droop control by the adder 79, it is possible to prevent the voltage control from becoming unstable.

[0076] Here, for example, there may be a difference between the current and voltage values ​​at the output terminals of the multiple power conversion devices 1 that are monitored by a higher-level device (not shown) and output to the power grid 5, and the current and voltage values ​​at the output terminals of the power conversion devices 1 that are monitored by their own sensors. In this case, for example, a correction may be made using an offset or the like so that there is no difference between these values. For example, if an active power command value P ＊ When this is output, it may appear to the host device (not shown) that the inverter is operating at 0%. In this case, the host device (not shown) uses an offset or the like to make it appear as if the inverter is operating at 0%. ＊ is sometimes output.

[0077] At this time, for example, suppose that due to some kind of disturbance, the measured active power value P takes a value less than 0%, such as -1% or -2%, and the DC capacitor 12 (see FIG. 1) is inadvertently charged. In this case, the power conversion device 1 (control device 30) attempts to control the DC capacitor 12 to the discharge side by outputting a command value of a positive value greater than 0%, such as 1% or 2%, using a DC-AVR or the like. However, due to the above offset or the like, for example, the active power command value P ＊ In this case, the power conversion device 1 (control device 30) generally uses the active power command value P ＊ Since priority is given to the discharge, discharge is not possible, and the DC voltage may become an overvoltage.

[0078] For this reason, in this embodiment, for example, when the DC capacitor 12 (see FIG. 1) is overcharged, that is, when it is determined that the DC voltage value calculated by the DC voltage determination unit 75 is equal to or greater than a predetermined threshold, the P droop control is executed by the adder 79. As a result, for example, the active power command value P ＊ Even if the value of P is 0% or a negative value less than 0%, the active power command value P＊ A positive value is added to the DC voltage, and the control device 30 can control the DC voltage in the discharge direction using a DC-AVR or the like. This makes it possible to control the DC voltage to a constant value using a DC-AVR or the like, stabilizing voltage control and suppressing DC overvoltage.

[0079] For example, if the power conversion device 1 is a power conversion device 1 for photovoltaic power generation, once the DC voltage is stabilized to a predetermined value by the DC-AVR, the control device 30 can terminate the DC-AVR and start the MPPT control. Note that, as described above, when the MPPT control is started, the function enabling unit 76 outputs information that the P droop control function is not enabled, and therefore the P droop control is not performed.

[0080] The subtractor 81 obtains from the adder 79 a P droop control value, which is the value obtained by executing the P droop control by the adder 79. The subtractor 81 also obtains the measured active power value P from the active power calculation unit 71. The subtractor 81 then subtracts the obtained measured active power P from the obtained P droop control value (takes the difference) to calculate an active power control value. The subtractor 81 then outputs the calculated active power control value to the feedback control unit 82.

[0081] The feedback control unit 82 obtains the active power control value calculated by the subtractor 81 from the subtractor 81, and performs feedback control on the obtained active power control value to obtain a feedback control value. The feedback control unit 82 outputs the obtained feedback control value to the second limiter 83.

[0082] The second limiter 83 acquires the feedback control value determined by the feedback control unit 82 from the feedback control unit 82, and limits the acquired feedback control value to a second feedback control value that is a value within a predetermined range. The second limiter 83 outputs the second feedback control value, which is the limited value of the feedback control value, to the second adder 85. By providing the second limiter 83, the d-axis current command value I ＊ ｄ It is possible to prevent the value from fluctuating significantly beyond the range limited by the second limiter.

[0083] Feedforward unit 84 obtains from adder 79 a P droop control value, which is the value obtained by performing P droop control by adder 79, and performs feedforward control on the obtained P droop control value to obtain a feedforward control value. Feedforward unit 84 outputs the obtained feedforward control value to second adder 85. Note that the function of feedforward unit 84 may be omitted, and only feedback control by feedback control unit 82 may be performed on the P droop control value.

[0084] The second adder 85 obtains, from the second limiter 83, a second feedback control value, which is a value obtained by limiting the feedback control value by the second limiter 83. The second adder 85 obtains, from the feedforward unit, the feedforward control value calculated by the feedforward unit 84. The second adder 85 then adds the obtained second feedback control value and the obtained feedforward control value to calculate the d-axis current command value I ＊ ｄ The second adder 85 calculates the calculated d-axis current command value I ＊ ｄ The information is output to the first adder 54 (see FIG. 1). When the function of the feedforward unit 84 is omitted, the second adder 85 adds the second feedback control value obtained from the second limiter 83 and the P droop control value obtained from the adder 79 to obtain the d-axis current command value I ＊ ｄ Calculate.

[0085] <Effects of One Embodiment> As described above, according to the one embodiment shown in FIGS. 1 and 2 , by introducing P droop control into the power conversion device, it is possible to prevent voltage control from becoming unstable when the active power command value takes a value of 0% or less and a negative offset is applied.

[0086] 1 and 2 , the integrator 72 integrates the active power measurement value P to calculate the charging power (amount of energy) only when it is determined that the active power measurement value P is in the charging direction. Furthermore, the gain unit 73 multiplies the acquired charging power by a predetermined gain K only when the active power measurement value P is in the charging direction. This allows the control device 30 (power control unit 44) to execute P droop control only when the active power measurement value P is in the charging direction.

[0087] 1 and 2, limiter 74 limits the first control value so as to perform P droop control in the charging direction (negative direction), thereby allowing control device 30 (power control unit 44) to perform P droop control only in the discharging direction (positive direction).

[0088] 1 and 2 , DC voltage determination unit 75 outputs “1” (high level) to AND circuit 77 only when it determines that the calculated DC voltage value is equal to or greater than a predetermined threshold. This allows control device 30 (power control unit 44) to execute P droop control only when a certain amount of charging voltage has accumulated, preventing excessive P droop control.

[0089] 1 and 2 , AND circuit 77 outputs information indicating that P droop control should be started ("1") to selector 78 only when the information from function enabler 76 and the information from DC voltage determiner 75 are "1" and "1". This allows control device 30 (power control unit 44) to prevent P droop control from being performed too quickly and to prevent P droop control from interfering with MPPT control.

[0090] 1 and 2 , when selector 78 receives from AND circuit 77 the information "0" indicating that P droop control will not be started, selector 78 selects the control value of "0.0" and outputs it to adder 79. This allows control device 30 (power control unit 44) to prevent P droop control from affecting subsequent control when the P droop control function is disabled.

[0091] <Hardware Configuration Example> Fig. 3 is a conceptual diagram showing an example of the hardware configuration of the processing circuitry 90 included in the control device 30 in the embodiment shown in Figs. 1 and 2. The functions described above are realized by the processing circuitry 90. In one aspect, the processing circuitry 90 includes at least one processor 91 and at least one memory 92. In another aspect, the processing circuitry 90 includes at least one dedicated hardware 93.

[0092] When the processing circuit 90 includes at least one processor 91 and at least one memory 92, each function is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. At least one of the software and firmware is stored in the memory 92. The processor 91 realizes each function by reading and executing the program stored in the memory 92.

[0093] The at least one processor 91 is, for example, a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP, etc. The at least one memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, an EEPROM, etc., a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, a DVD, etc.

[0094] When the processing circuit 90 includes at least one dedicated hardware 93, the processing circuit 90 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. Each function of the control device 30 is realized by the processing circuit 90.

[0095] The functions of the control device 30 may be partially or entirely implemented by hardware, or may be implemented as a program executed by a processor. That is, the control device 30 may be implemented by a computer and a program, and the program may be stored in a storage medium or provided via a network.

[0096] 1 to 3, the power conversion device 1 for photovoltaic power generation has been described as an example of one aspect of the present disclosure, but the present disclosure is not limited to this. The present disclosure can also be applied to, for example, a power conversion device for a binary power generation system or a power conversion device for a predetermined storage battery (ESS: Energy Storage System) as long as the power conversion device 1 performs only charging, power generation, and discharge as basic operations.

[0097] 1 to 3, the power conversion device 1 for photovoltaic power generation and the control device 30 included therein have been described as an example of one aspect of the present disclosure, but the present disclosure is not limited to this. The present disclosure can also be realized as a control method in which processing steps are performed in each part of the control device 30.

[0098] The present disclosure can also be realized as a control program that causes a computer to execute the processing steps in each part of the control device 30.

[0099] The present disclosure can also be realized as a storage medium (non-transitory computer-readable storage medium) on which a control program is stored. The control program can be stored and distributed on removable media such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a USB (Universal Serial Bus) memory. The control program may be uploaded to a network via a network interface (not shown) of the control device 30, or may be downloaded from the network and stored in the storage unit 60.

[0100] The features and advantages of the embodiments will be apparent from the above detailed description. It is intended that the claims encompass the features and advantages of the above-described embodiments without departing from the spirit and scope of the claims. Furthermore, any improvements and modifications will be readily apparent to those skilled in the art. Therefore, it is not intended that the scope of the inventive embodiments be limited to the above-described embodiments, and appropriate improvements and equivalents within the scope of the disclosed embodiments may be utilized.

[0101] 1...power conversion device; 2...DC bus; 3...AC circuit; 4...DC power source; 5...AC power system (power system, system); 11...DC switch (DC switch, DC circuit breaker); 12...DC capacitor (DC capacitor); 13...inverter (inverter circuit); 14...AC reactor (AC reactor); 15...AC capacitor (AC capacitor); 15a...branch point; 16...AC switch (AC switch, AC circuit breaker); 21...first current sensor; 22...first voltage sensor; 23...second current sensor; 24...second voltage sensor; 25...third current sensor; 30...control device; 41...PLL control unit; 42...first conversion unit; 43...second conversion unit; 44...power control unit; 51...MPPT control unit (maximum power point tracking control unit); 52...first subtraction unit; 53...DC voltage control unit; 54...first addition unit; 55...third conversion unit; 56...second subtraction unit; 57...current control unit; 58...PWM control unit (pulse width modulation control unit); 60...storage unit; 71...active power calculation unit; 72...integrator; 73...gain unit; 74...limiter; 75...DC voltage determination unit; 76...function activation unit; 77...logical product circuit; 78...selector; 79...adder; 81...subtractor; 82...feedback control unit; 83...second limiter; 84...feedforward unit; 85...second adder; 90...processing circuit; 91...processor; 92...memory; 93...hardware; G...gate signal; I ＊ ｄ ...d-axis current command value; I ＊ ｑ ...q-axis current command value; I ＊ ＡＣ ...current command value; I ＡＣ ... inverter output current value (inverter output current); I ＤＣ ... DC current value (DC current); I Ｇｒｉｄ ...system current value (system current); K...gain; P...active power measurement value (active power value, active power); P ＊ ...active power command value; V ＊ ＤＣ ... DC voltage command value; V ＤＣ ... DC voltage value (DC voltage); V Ｇｒｉｄ …system voltage value (system voltage); θ…reference phase

Claims

1. An active power calculation unit that acquires a current value and a voltage value measured on the AC side of a power conversion device, and calculates an active power value that is a measured value of the active power output by the power conversion device based on the acquired current value and voltage value; An integrator that acquires the active power value from the active power calculation unit and integrates the active power value only when the acquired active power value is in the charging direction to calculate the charging power; A gain calculator that calculates a first control value by multiplying the charging power integrated by the integrator by a predetermined gain; A DC voltage determination unit that acquires the first control value calculated by the gain calculator, calculates a DC voltage value from the charging power based on the acquired first control value, and determines whether the calculated DC voltage value is equal to or greater than a predetermined threshold; When the DC voltage determination unit determines that the DC voltage value is equal to or greater than the predetermined threshold, an adder that adds a predetermined active power command value and the first control value to execute P-loop control. A control device for a power conversion device, characterized by comprising:

2. In the control device according to claim 1, A function activation unit that monitors the operation mode of the power conversion device and outputs information on whether the function of the P-loop control is effective based on the operation mode; A logical product circuit that acquires information indicating that the function of the P-loop control is effective from the function activation unit, and when acquiring information indicating that the DC voltage value has been determined to be equal to or greater than the predetermined threshold by the DC voltage determination unit, outputs information indicating that the P-loop control should be started; A selector that outputs the first control value calculated by the gain calculator when information indicating that the P-loop control should be started is output by the logical product circuit, and outputs a control value of 0.0 when information indicating that the P-loop control should be started is not output by the logical product circuit; Further comprising: The adder adds the predetermined active power command value and the value output from the selector to execute the P-loop control. A control device for a power conversion device, characterized by comprising:

3. In the control device according to claim 2, The function activation unit outputs information indicating that the function of the P-loop control is effective when the power conversion device is in DC-AVR. A control device for a power conversion device, characterized by comprising:

4. In the control device according to claim 3, a limiter that acquires the first control value calculated by the gain device and limits it to a second control value that is a value within a predetermined range, and further comprising, when the selector outputs information indicating that the P-loop control should be started by the logical AND circuit, outputs the second control value which is the value limited by the limiter for the first control value, and when the information indicating that the P-loop control should be started is not output by the logical AND circuit, outputs a control value of 0.

0. A control device for a power conversion device, characterized in that.

5. In the control device according to claim 4, a subtractor that subtracts the active power value from the P-loop control value which is the value obtained by executing the P-loop control by the adder to calculate an active power control value, a feedback control unit that executes feedback control on the active power control value calculated by the subtractor to obtain a feedback control value, and a second adder that adds the P-loop control value and the feedback control value obtained by the feedback control unit to calculate a d-axis current command value. A control device for a power conversion device, characterized in that it further comprises.

6. In the control device according to claim 5, a feedforward unit that executes feedforward control on the P-loop control value to obtain a feedforward control value, and further comprising, the second adder calculates the d-axis current command value by adding the feedforward control value obtained by the feedforward unit and the feedback control value. A control device for a power conversion device, characterized in that.

7. In the control device according to claim 6, a second limiter that acquires the feedback control value obtained by the feedback control unit and limits it to a second feedback control value that is a value within a predetermined range, and further comprising, the second adder calculates the d-axis current command value by adding the feedforward control value and the second feedback control value which is the value limited by the second limiter. A control device for a power conversion device, characterized in that.

8. A power conversion device comprising: an inverter that converts direct current power into alternating current power; and the control device according to any one of claims 1 to 7.

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