Power conversion device and air conditioning device

Abstract

To suppress oscillation in the control of harmonic current components when a power conversion device outputs a fundamental current component during load shutdown.SOLUTION: An air conditioning device includes a load connected to a power supply, and a power conversion device connected in parallel with the load to the power supply. The power conversion device includes a current source that outputs a fundamental wave current component and harmonic current components to the power supply to which the load is connected, and a controller that controls the current output by the current source. The controller includes an element having gain for frequency components that are integer multiples of a predetermined frequency within the harmonic current components, and disables the element having gain when the drive state of the load corresponds to a predetermined drive state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device and an air conditioning device. [Background technology]

[0002] Patent Document 1 discloses an active filter device connected to a harmonic generating device, which includes a current source that passes a compensation current (Ic) for improving the power factor to a power system to which the harmonic generating device is connected, and a power factor controller that determines the magnitude of the compensation current by adding a set value corresponding to a reactive current in devices other than the harmonic generating device to the load current of the current flowing from the power system to the harmonic generating device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-191375 Summary of the Invention [Problem to be solved by the invention]

[0004] When a power conversion device connected in parallel to a load connected to a power source outputs a fundamental current component in addition to harmonic current components to adjust the voltage of a power distribution system, the fundamental current component may be output even when the load is stopped. If the power conversion device outputs the fundamental current component when the load is stopped, oscillation may occur in the control of the harmonic current component depending on, for example, the line impedance of the power source or the constant of a noise filter inserted in the front stage of the load. The present disclosure aims to suppress oscillation in the control of harmonic current components when a power conversion device outputs fundamental current components during load stoppage. [Means for solving the problem]

[0005] A power conversion device according to the present disclosure includes a load connected to a power source, a current source connected to the power source and in parallel with the load, the current source outputting a fundamental current component and a harmonic current component to the power source connected to the load, and a controller controlling the current output by the current source, the controller including an element having a gain for frequency components of the harmonic current components that are integer multiples of a predetermined frequency, and disabling the element having the gain when the load is in the predetermined driving state. In this case, when the power conversion device outputs the fundamental current component when the load is stopped, oscillation in the control of the harmonic current component can be suppressed. From another perspective, a power conversion device according to the present disclosure includes a load connected to a power source, a current source connected to the power source and in parallel with the load, the current source outputting a fundamental current component and a harmonic current component to the power source connected to the load, and a controller controlling the current output by the current source, wherein the controller disables control of the harmonic current component when the load is in a predetermined drive state. In this case, when the power conversion device outputs the fundamental current component when the load is stopped, oscillation in the control of the harmonic current component can be suppressed. Here, the predetermined drive state is a state in which any one of the power of the load, the current flowing through the load, the DC voltage ripple occurring in the load, or the rotation speed of the load is equal to or less than a predetermined value, and in this case, it is possible to suppress oscillation in the control of harmonic current components according to the drive state of the load. The predetermined drive state is a state in which a stop signal for the load is received from an external device, and in this case, oscillation can be suppressed in the control of harmonic current components in response to the external signal. The controller calculates the fundamental current component and the harmonic current component from the current flowing through the power conversion device, acquires information about the power source, sets a first target value for the fundamental current component based on the acquired information about the power source, sets a second target value for the harmonic current component based on the current flowing through the load, and controls the fundamental current component and the harmonic current component based on the first target value and the second target value. In this case, the voltage of the power distribution system can be adjusted by the power conversion device. Furthermore, the controller includes a repetitive control in an element having a gain for a frequency component that is an integer multiple of the predetermined frequency, and disables the repetitive control when a state value related to driving the load is equal to or less than a predetermined value. In this case, when the power conversion device outputs a fundamental wave current component when the load is stopped, oscillation in the repetitive control can be suppressed. Furthermore, the controller controls the fundamental current component and the harmonic current component separately, and in this case, control responses can be set separately to obtain control performance according to frequency. Furthermore, the load is incorporated into an air conditioner. In this case, harmonic current components generated by the air conditioner can be compensated for by the power conversion device. The air conditioner of the present disclosure incorporates the power conversion device according to claim 1 or 2. In this case, when the power conversion device outputs a fundamental current component when the load in the air conditioner is stopped, oscillation in the control of harmonic current components can be suppressed. The air conditioner of the present disclosure includes a plurality of power conversion devices according to claim 1 or 2, and the plurality of power conversion devices share the responsibility of outputting the fundamental wave current component and the harmonic current component. In this case, the output amount per power conversion device can be reduced. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a diagram illustrating a configuration example of an active filter device according to an embodiment of the present invention. [Figure 2]1A and 1B are diagrams illustrating a repetitive controller, in which FIG. 1A shows a basic configuration example of a harmonic current controller, and FIG. 1B shows a specific configuration example of a harmonic current controller. [Figure 3] 1A and 1B are diagrams showing examples of frequency characteristics of a repetitive controller, where FIG. 1A shows frequency-amplitude characteristics and FIG. 1B shows frequency-phase characteristics. [Figure 4] FIG. 10 is a diagram illustrating an example of the configuration of a harmonic current controller in the case where a repetitive controller is provided before a PI current controller. [Figure 5] 1A and 1B are diagrams illustrating invalidation of control, in which (a) shows an example of invalidating control in a harmonic current controller, and (b) shows an example of invalidating repetitive control in a repetitive controller. [Figure 6] 1A and 1B are diagrams showing current waveforms when an active filter device outputs a compensation current when a load is stopped, where (a) shows the current waveform when repetitive control in a repetitive controller is activated, and (b) shows the current waveform when repetitive control in a repetitive controller is deactivated. [Figure 7] 1A and 1B are diagrams showing examples of the configuration of a current controller that performs harmonic current control and fundamental current control of the q-axis component, where (a) shows an example of the configuration of a current controller when a repetitive controller is provided after a multiplier, and (b) shows an example of the configuration of a current controller when a repetitive controller is provided before a multiplier. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. <Configuration of active filter device> Fig. 1 is a diagram showing an example of the configuration of an active filter device 100 according to this embodiment. Fig. 1 shows a case in which the active filter device 100 is incorporated into an air conditioning device 36. The active filter device 100 is an example of a power conversion device. In the illustrated example, the active filter device 100 is incorporated into the air conditioner 36, but the present invention is not limited to this. The active filter device 100 may be installed in a location different from the air conditioner 36. In addition, in the illustrated example, a configuration is shown in which the air conditioning device 36 is the load, but this is not limiting. The load may be a device having a power converter 60. Examples of devices having a power converter 60 include water heaters and inverters for factory lines.

[0008] If the load includes an inverter circuit, the inverter circuit performs switching at a frequency higher than the fundamental frequency of the power supply 20, causing harmonic currents to be added to the current in the power distribution system and affecting the power supply. Therefore, the active filter device 100 suppresses the harmonic currents by passing a compensating current through the power distribution system. The fundamental wave is a sine wave consisting of frequency components of the power supply 20. For example, if the frequency of the power supply is 50 Hz, the frequency of the fundamental wave will be 50 Hz. Harmonics are frequency components that are integer multiples of the fundamental wave. An integer multiple is two or more. Therefore, the fundamental wave is not included in harmonics. In this disclosure, the fundamental wave component of a current is referred to as a fundamental wave current, and the harmonic component of a current is referred to as a harmonic current. Furthermore, the harmonic current discussed in this disclosure is a current that includes harmonic components of the second to fortieth orders.

[0009] Furthermore, the active filter device 100 described in this embodiment has a function of adjusting the voltage of a power distribution system, and is configured to output a compensating current for a fundamental current in addition to a harmonic current. If the active filter device 100 outputs only harmonic currents, harmonic currents are not generated when the load is stopped, so the active filter device 100 may be stopped. However, if the active filter device 100 outputs a fundamental current in addition to harmonic currents, the active filter device 100 may continue to output the fundamental current without being stopped. The active filter device 100 outputs fundamental components in addition to harmonic currents, and outputs the fundamental current without being stopped, even when the load is stopped.

[0010] The air conditioning device 36 is installed in a building such as a building, a factory, an apartment building, a hospital, or a detached house. Power is supplied to the building or the like from a power source 20 via a power distribution line 21. Here, the power source 20 and the power distribution line 21 are collectively referred to as a power distribution system. The power distribution line 21 has a power distribution line impedance 22. The power source 20 is, for example, a three-phase AC power source (commercial power source). The air conditioner 36 includes a refrigerant circuit (not shown) in which a refrigerant circulates to perform a refrigeration cycle operation, and performs indoor cooling and heating in a building, etc. The refrigerant circuit of the air conditioner includes a compressor that compresses the refrigerant. The air conditioner 36 includes a power converter 60 .

[0011] As shown in FIG. 1 , the power converter 60 of the air conditioner 36 includes a converter circuit 61, a reactor 62, a capacitor 63, an inverter circuit 64, a motor 65, and a noise filter 66. The converter circuit 61 is a circuit that converts AC to DC. The converter circuit 61 is, for example, a diode bridge circuit. The capacitor 63 smoothes the output of the converter circuit 61. The inverter circuit 64 converts the DC smoothed by the capacitor 63 into AC of a predetermined frequency and a predetermined voltage. The inverter circuit 64 includes, for example, multiple (six in this case) bridge-connected switching elements, and converts the input DC into AC by switching the DC. The configuration of the power converter 60 is not limited to the example shown in the figure. The converter circuit 61 may include a switching element, or the DC section may include a buffer circuit including a switching element.

[0012] The motor 65 of the power converter 60 of the air conditioner 36 is, for example, an interior permanent magnet motor (IPM motor). The motor 65 drives a compressor provided in the refrigerant circuit. The motor 65 is an example of a load. If no special measures are taken, the operation of the motor 65 will result in a large current in the power distribution system (hereinafter referred to as the system current (I S In other words, the power converter 60 is an example of a device that generates harmonic currents.

[0013] 1 includes a current source 110, a control unit 120, and a PWM controller 141. The active filter device 100 is connected to a power source 20 in parallel with a power converter 60. The active filter device 100 generates a compensation current (I C ) to the power distribution system, the fundamental power factor is improved and the harmonic current of the power converter 60 in the air conditioner 36 is suppressed. C ) is positive when it flows from the current source 110 to the power distribution system. S ) and compensation current (I C ) is the load current (I L )

[0014] The current source 110 includes an inverter circuit 111 and a capacitor 113. The capacitor 113 is, for example, an electrolytic capacitor. The inverter circuit 111 generates a compensation current (I C ) is input and output to charge and discharge the capacitor 113. In this example, the inverter circuit 111 is connected to the power distribution system via a three-phase reactor 146. Similar to the inverter circuit 64, the inverter circuit 111 is configured with a plurality of (six in this case) bridge-connected switching elements 112. The inverter circuit 111 changes the switching states (on / off states) of the plurality of switching elements 112 in synchronization with a drive signal G of a predetermined frequency output by the PWM controller 141, and generates a compensation current (I C ) is input and output. In Figure 1, the compensation current (I C ) is provided between the reactor 146 and the connection point between the power distribution system and the power converter 60. The low pass filter 145 is a so-called LC filter.

[0015] The control unit 120 includes a power supply phase detector 121, a phase calculation unit 122, two current sensors 123 and 124, two dq converters 125 and 126, three high-pass filters (HPF) 127, 133 and 135, two adders 128 and 137, three subtractors 129, 134 and 138, a voltage controller 130, two current controllers 132 and 140, a harmonic current controller 136, and a low-pass filter (LPF) 139. Specifically, the main parts of the control unit 120 can be configured using a microcomputer, a memory device in which software for operating the microcomputer is stored, and the like.

[0016] The power supply phase detector 121 is connected to predetermined lines (any two of the r-phase, s-phase, and t-phase) of the power distribution system, detects the phase of the line voltage, and outputs it to the phase calculation unit 122. The phase calculation unit 122 uses the signal (called the zero-cross signal (S1)) output by the power supply phase detector 121 to determine the phase (ωt) of the power distribution system. The phase calculation unit 122 outputs the determined phase (ωt) to the dq converter 125 and the dq converter 126. The current sensor 123 detects the load current (I L The current sensor 123 detects the three-phase load current (I L ), the load current for two phases (i rL , i tL ) to detect.

[0017] The current sensor 124 detects the compensation current (I C The current sensor 124 detects the three-phase compensation current (I C ) of the load current of two phases. L ), and compensation current (I C ) can easily calculate the current value of the remaining phase by detecting the current values ​​of two of the three phases, so each of the current sensors 123, 124 may be configured to detect currents for two phases. Current sensors of various configurations can be used for the current sensors 123, 124. One example of the current sensors 123, 124 is a current transformer.

[0018] The dq converter 125 converts the load current (IL ) (three phases), a three-phase / two-phase transformation (dq axis transformation) is performed. Here, the d axis and q axis are a rotating coordinate system that rotates in synchronization with the phase (ωt) calculated by the phase calculation unit 122.

[0019] The d-axis component obtained as a result of the conversion by the dq converter 125 is the active current in the power converter 60 of the air conditioner 36. The dq converter 125 converts the d-axis component (hereinafter referred to as the d-axis component (i dL )) to the high-pass filter 127. The q-axis component obtained as a result of the conversion by the dq converter 125 is a reactive current in the power converter 60 of the air conditioner 36. The dq converter 125 converts the q-axis component (hereinafter referred to as the q-axis component (i qL )) is output to the high-pass filter 133.

[0020] The dq converter 126 converts the compensation current (I C ) is converted from three-phase to two-phase, and the d-axis component, which is the active current (hereinafter referred to as the d-axis current (i d ) and the q-axis component, which is the reactive current (hereafter referred to as the q-axis current (i q ) is calculated. d ) is output to the subtractor 131. Also, the q-axis current (i q ) is output to high-pass filter 135 and low-pass filter 139.

[0021] The high-pass filter 127 is a filter that filters the load current (I L ) d-axis component (i dL ) and outputs it to the adder 128. The output of the dq converter 125 is the load current (I L If there are no harmonic components in the load current (I L ) that is synchronized with the phase of the power supply 20 appears as a direct current. L ) is output to the adder 128.

[0022] Compensation current (I C) are the d-axis and q-axis components of the load current (I L ) to match the harmonic components of the compensation current (I C ) flows, the load current (I L ) can be cancelled out. Hereinafter, flowing a current so as to cancel out a predetermined component in this way is referred to as compensation. That is, the output of the high-pass filter 127 is a compensation current (I C ) d-axis component (d-axis current (i d )) command value (d-axis current command value (i * d ) can be used to generate

[0023] In this example, the d-axis current command value (i * d ) is not used as it is, but the voltage between the terminals of the capacitor 113 (hereinafter referred to as DC voltage (V dc Specifically, the control unit 120 first calculates the DC voltage (V dc ) and its command value (V * dc ) is calculated. The voltage controller 130 performs proportional-integral control (PI control) based on the deviation calculated by the subtractor 129 to calculate a correction value. This correction value is added to the output of the high-pass filter 127 in the adder 128, and the result of the addition is calculated as the d-axis current command value (i * d ) is output as a DC voltage (V dc The subtractor 131 reduces the influence of fluctuations in the d-axis current (i d ) to the d-axis current command value (i * d ) minus the deviation (Δi d ) and calculate the deviation (Δi d ) to the current controller 132.

[0024] The current controller 132 calculates the deviation (Δi d) based on the feedback control (for example, so-called PID control) algorithm, the d-axis voltage command value (v * d ) is output.

[0025] The high-pass filter 133 is a filter that filters the load current (I L ) q-axis component (i qL ) to remove the DC component and obtain the q-axis current command value (i * qh ) is output to the subtractor 134. The q-axis current (i q ) is output to the high-pass filter 135 and the low-pass filter 139. The q-axis current (i qh ) is output to the subtractor 134. The subtractor 134 outputs the q-axis current command value (i * qh ) to the q-axis current (i qh ) (hereinafter referred to as the deviation (Δi qh ) is calculated, and the deviation (Δi qh ) is output to a harmonic current controller 136, which controls the harmonic components. The harmonic current controller 136 receives the q-axis current (i qh ) is input. When the high-pass filter 135 passes only harmonic components of, for example, 100 Hz or higher, the deviation (Δi qh ) is the compensation current (I C The harmonic current controller 136 is used to suppress and control the harmonic current in the qh ) and performs control using an algorithm such as feedback control (for example, so-called PID control).

[0026] The q-axis current (i ql ) is input to the subtractor 138. The q-axis current (i ql ) is the fundamental current of the power supply frequency of 50 Hz or 60 Hz. The subtractor 138 receives a current command value (i * ql) is input to the subtractor 138. The subtractor 138 calculates the current command value (i * ql ) to the q-axis current (i ql ) minus the deviation (Δi ql ) is input to the current controller 140, which controls the fundamental wave component. The current controller 140 calculates the deviation (Δi ql ) and performs control using an algorithm such as feedback control (for example, so-called PID control).

[0027] The current command value (i * ql ) is set based on information about the power source 20. The control unit 120 acquires information about the power, voltage, current, and power factor output by the power source 20 as information about the power source 20. The control unit 120 may receive the information about the power source 20 from a device storing information about the power source 20, such as a server of a management company, via a communication unit (not shown), or may calculate the information about the power source 20 from the current detected by the current sensors 123 and 124. Then, the control unit 120 sets the current value previously associated with the acquired information of the power source 20 as the current command value (i * ql ) is set as the current command value (i * ql The method for setting the current command value (i * ql ) may be set.

[0028] The harmonic current controller 136 controls harmonic current components of 100 Hz or higher, while the current controller 140 controls fundamental current components of 60 Hz or 50 Hz. The current control response of the harmonic current components by the harmonic current controller 136 and the current control response of the fundamental current component by the current controller 140 can be set separately. Note that, since the higher the frequency, the more delay in control occurs, it is necessary to set the control response of the harmonic current controller 136 higher than that of the current controller 140 based on the frequency component to be controlled. In this way, having separate current controllers corresponding to the frequency components to be controlled has the effect of allowing separate control responses to be set and achieving control performance according to the frequency.

[0029] The adder 137 outputs the harmonic current controller 136 (v * qh ) and the output of the current controller 140 (v * ql ) to obtain the q-axis voltage command value (v * q ) and outputs it to the PWM controller 141.

[0030] The PWM controller 141 controls the d-axis voltage command value (v * d ) and q-axis voltage command value (v * q ) to generate a drive signal (G) for driving the current source 110. The PWM controller 141 performs so-called PWM (pulse width modulation) control to supply a compensation current (I C The PWM controller 141 can be configured using a microcomputer and a memory device that stores software for operating the microcomputer.

[0031] <Operation of the active filter device 100> The active filter device 100 is incorporated in the air conditioner 36, and the active filter device 100 operates when the air conditioner 36 is energized. In the control unit 120, a dq converter 125 converts the load current (I L ) d-axis component (i dL ) and q-axis component (i qL ) is required.

[0032] q-axis component (i qL ) is filtered by a high-pass filter 133 to remove the DC component, and the q-axis current command value (i * qh ) is output. d-axis component (i dL ) has its DC component removed by a high-pass filter 127 and is output to an adder 128. The adder 128 outputs the DC voltage (V dc ) and its command value (V * dc) and the d-axis component (i dL ) to obtain the d-axis current command value (i * d ) is output.

[0033] In addition, the dq converter 126 generates a compensation current (I C ) d-axis current (i d ) and q-axis current (i q ) is obtained by the subtractor 131. * d ) from the d-axis current (i d ) is subtracted to obtain the deviation (Δi d ) is calculated. q-axis current (i q ) passes through a high-pass filter 135 or a low-pass filter 139, and is subtracted by a subtractor 134 or 138 to obtain a q-axis current command value (i * qh ), current command value (i * ql ) deviation Δi qh , Δi ql is calculated.

[0034] Deviation (Δi d ) is determined, the current controller 132 outputs the d-axis voltage command value (v * d ) is output to the PWM controller 141. Also, the deviation (Δi qh ) is determined, the harmonic current controller 136 outputs v * qh is output, and the deviation (Δi ql ) is determined, the current controller 140 outputs v * ql These outputs are added together by an adder 137 to obtain the q-axis voltage command value (v * q ) is output to the PWM controller 141. Then, the d-axis voltage command value (v * d ) and q-axis voltage command value (v * q ) is output from the PWM controller 141 to the inverter circuit 111.

[0035] <Repetition control> In this embodiment, the harmonic current controller 136 for the harmonic current components includes a repetitive controller 150 (see FIG. 2). The repetitive controller 150 performs repetitive control by storing one cycle of the input signal and outputting it with a delay of one cycle. When outputting, the harmonic current controller 136 adds the value output by the repetitive controller 150 from one cycle before to the output. The repetitive control makes it possible to perform control that compensates for the phase delay caused by the delay in harmonic current control, thereby improving the performance of compensating for harmonic currents.

[0036] 2 is a diagram for explaining the repetitive controller 150, in which (a) shows an example of the basic configuration of the harmonic current controller 136, and (b) shows an example of a specific configuration of the harmonic current controller 136. Note that (a) also shows the high-pass filter 135, the low-pass filter 139, and the current controller 140.

[0037] As shown in FIG. 2( a ), the harmonic current controller 136 includes a repetitive controller 150 , a PI current controller 151 , and an adder 152 . The harmonic current controller 136 subtracts the deviation (Δi qh ) is input. The PI current controller 151 calculates the input deviation (Δi qh ) is calculated by proportional-integral control (v * qhpi ) is output.

[0038] The repetitive controller 150 receives the input (v * qhpi ) is stored as a voltage value for one period, delayed by one period, and multiplied by the gain (v * qhrpt ) is output. The adder 152 receives the output of the repetition controller 150 (v * qhrpt ) and the output of the PI current controller 151 (v * qhpi ) and is added to obtain v as the output of the harmonic current controller 136.* qh Output. Then, the adder 137 calculates the output (v * qlpi ) to obtain the q-axis voltage command value (v * q ) to the PWM controller 141.

[0039] The current controller 140 is a PI current controller and receives an input (Δi ql ) is calculated by proportional-integral control (v * qlpi ) is output. Note that (v * qlpi ) is the v in Figure 1 * ql is the same as

[0040] As shown in FIG. 2( b ), the repetition controller 150 includes an adder 153 , a storage device 154 , and a multiplier 155 . The PI current controller 151 of the harmonic current controller 136 acts as a multiplier to multiply the input deviation (Δi qh ) to the gain (K pqh ) multiplied by (v * qhp ) is output. Note that (v * qhp ) is the (v * qhpi ) is the same as

[0041] The adder 153 adds the output of the PI current controller 151 and the output of the storage device 154 and inputs the result to the storage device 154 . The storage device 154 stores the q-axis current command value (i * qh ) for one period, and outputs it with a delay of one period. Multiplier 155 applies a gain (K rptqh ) and the output of the repeat controller 150 (v * qhrpt ) is obtained.

[0042] 3A and 3B are diagrams showing examples of frequency characteristics of the repetition controller 150, where (a) shows the frequency-amplitude characteristics and (b) shows the frequency-phase characteristics. In FIG. 3A, the horizontal axis shows frequency (Hz) and the vertical axis shows amplitude (dB). In FIG. 3B, the horizontal axis shows frequency (Hz) and the vertical axis shows phase (deg). Note that the signal (v * qhp ) has a frequency of 60Hz.

[0043] As shown in FIGS. 3(a) and 3(b), the amplitude and phase of the signal output from the repetition controller 150 differ depending on the frequency of the input signal. 3(a) shows that the repetition control in the repetition controller 150 has a gain for frequency components that are integer multiples of a frequency of 60 Hz. Note that the frequency components for which the repetition controller 150 has a gain are not limited to integer multiples of 60 Hz. The repetition controller 150 has a gain for detected frequency components that are integer multiples of a predetermined frequency. The predetermined frequency is determined by the frequency of the power source 20. Furthermore, as shown in FIG. 3(b), the higher the frequency of the input signal, the more phase delay occurs in the signal output by the repetitive controller 150.

[0044] The repetitive controller 150 and the PI current controller 151 are not limited to the configuration in which the repetitive controller 150 is provided after the PI current controller 151 as shown in Fig. 2. The repetitive controller 150 may be provided before the PI current controller 151. 4 is a diagram showing an example of the configuration of the harmonic current controller 136 when a repetitive controller 150 is provided before the PI current controller 151. The configuration of the repetitive controller 150 is similar to that shown in FIG. 2(b).

[0045] In the example shown in FIG. 4, the harmonic current controller 136 receives the deviation (Δi qh ) is input. The repetitive controller 150 calculates the input deviation (Δi qh ) for one period, and outputs it with a delay of one period. The adder 152 subtracts the deviation (Δi qh ) is added with the output of the repetitive controller 150 and output to the PI current controller 151. The PI current controller 151 has a gain (K pqh ) and output v as the harmonic current controller 136 output. * qh Output. Then, the output (v * qh ) and the output (v * qlpi ) are added together to obtain the q-axis voltage command value (v * q ) to the PWM controller 141 (see FIG. 1).

[0046] <Invalidation process> In this embodiment, the active filter device 100 outputs a fundamental current component even when the load is stopped. If the active filter device 100 outputs a fundamental current component when the load is stopped, oscillation may occur in the control of the harmonic current component. In order to suppress oscillation in the control of the harmonic current component, in this embodiment, the control unit 120 disables the control in the harmonic current controller 136 or disables the repetitive control in the repetitive controller 150 when the motor 65, which is an example of a load, is in a predetermined driving state.

[0047] The predetermined drive state is a state in which it can be determined that the motor 65 (see FIG. 1), which is an example of a load, is stopped, and refers to a state in which, for example, any of the power of the motor 65, the current flowing through the motor 65, the power of the power converter 60, the current flowing through the power converter 60, the DC voltage ripple generated in the power converter 60, or the rotation speed of the motor 65 is equal to or less than a predetermined value. The DC voltage ripple is an oscillation component of the DC voltage generated in the capacitor 63 (see FIG. 1), and the DC voltage ripple becomes small when the motor 65 is stopped. The predetermined value may be set differently depending on the type of the motor 65. The predetermined driving state may also be a state in which a stop signal is received from the outside.

[0048] 5A and 5B are diagrams for explaining the invalidation of control, in which (a) shows an example of invalidating the control in the harmonic current controller 136, and (b) shows an example of invalidating the repetitive control in the repetitive controller 150. In FIG. As shown in Fig. 5(a), the control unit 120 (see Fig. 1) disables the control in the harmonic current controller 136 by turning off the input of a signal to the harmonic current controller 136 or the output of a signal from the harmonic current controller 136. The control unit 120 also disables the control in the harmonic current controller 136 by stopping the harmonic current controller 136. The control unit 120 may also disable the control in the harmonic current controller 136 by lowering the control gain of the harmonic current controller 136.

[0049] 5(b), the control unit 120 disables the repetition control in the repetition controller 150 by turning off the input of a signal to the repetition controller 150 or the output of a signal from the repetition controller 150. The control unit 120 also disables the repetition control in the repetition controller 150 by stopping the repetition controller 150. The control unit 120 may also disable the repetition control in the repetition controller 150 by lowering the control gain of the repetition controller 150.

[0050] FIG. 6 shows the compensation current (I C 6(a) and 6(b) show the current waveforms when the repetitive control in the repetitive controller 150 is activated, and (b) shows the current waveforms when the repetitive control in the repetitive controller 150 is deactivated. In FIGS. 6(a) and 6(b), the horizontal axis represents time (ms) and the vertical axis represents current (A).

[0051] When a load is stopped, only the fundamental current should flow, and no harmonic current should flow. However, depending on the constants of the distribution line impedance 22 and the noise filter 66 (see Figure 1), harmonic noise may occur when the load is stopped. If harmonic current control is performed in real time, control that suppresses harmonic noise can be performed. However, when harmonic current control is performed repeatedly, the harmonic current is controlled using data from one cycle ago, and therefore the harmonic current control cannot keep up with high-frequency noise, which can result in oscillation. The cycle delay causes unnecessary compensation, resulting in oscillation. In other words, the cycle delay causes the set q-axis current command value (i * qh ) oscillates, and the harmonic current (i qh ) also oscillates.

[0052] As shown in FIG. 6(a), when the repetitive control is in operation and the load is stopped, the active filter device 100 generates a compensation current (I C ) is output, the harmonic current (i qh ) oscillates. On the other hand, as shown in FIG. 6(b), when the repetitive control is disabled and the load is stopped, the active filter device 100 generates a compensation current (I C ) is output, the harmonic current (i qh ) oscillation is suppressed.

[0053] In this way, when the motor 65, which is an example of a load, is in a predetermined driving state, the control in the harmonic current controller 136 or the repetitive control in the repetitive controller 150 can be disabled, thereby suppressing oscillation in the control of the harmonic current components.

[0054] A plurality of active filter devices 100 are incorporated in the air conditioner 36, and the compensation current (I C ) to the power distribution system. In this case, each of the active filter devices 100 has the components shown in FIG. 1 and is connected in parallel with the power converter 60 to the power source 20. A compensation current (IC ) is output.

[0055] In addition, in this embodiment, the q-axis current component control, which is a reactive current, is performed by the harmonic current controller 136 and the current controller 140, but this is not limiting. The q-axis component harmonic current control and the fundamental current control may be performed by a single controller. An example in which the q-axis component harmonic current control and the fundamental current control are performed by a single current controller 160 will be described.

[0056] 7A and 7B are diagrams showing examples of the configuration of a current controller 160 that performs harmonic current control and fundamental current control of the q-axis component, where (a) shows an example of the configuration of the current controller 160 when a repetitive controller 170 is provided after the multiplier 173, and (b) shows an example of the configuration of the current controller 160 when a repetitive controller 170 is provided before the multiplier 173. In the example shown in FIG. 7(a), the current command value (i * ql ) and the q-axis current command value (i * qh ) are added together in an adder 171. Then, in a subtractor 172, the q-axis current (i q ) deviation (Δi q ) is calculated and output to the current controller 160.

[0057] The multiplier 173 multiplies the deviation (Δi q ) to the gain (K pq ) multiplied by (v * qpi ) is output. The repetition controller 170 receives the input (v * qpi ) for one period, delay it by one period, multiply it by the gain, and output it. The adder 174 receives the output of the repetition controller 170 (v * qrpt ) and the output of multiplier 173 (v * qpi) and is added to obtain v as the output of the current controller 160. * q Output.

[0058] In the example shown in FIG. 7(b), the process is the same as in FIG. 7(a) up to the output by the subtractor 172. The repetitive controller 170 calculates the input deviation (Δi q ) for one period, delay it by one period, multiply it by the gain, and output it. The adder 174 subtracts the deviation (Δi q ) is added with the output of the repeat controller 170 and output to the multiplier 173. The multiplier 173 multiplies the input by a gain and outputs v as the output of the current controller 160. * q Output.

[0059] <Effects> The active filter device 100 of the present disclosure includes a load connected to a power source 20, a current source 110 connected to the power source 20 and in parallel with the load, the current source 110 outputting fundamental and harmonic current components to the power source 20 connected to the load, and a control unit 120 controlling the current output by the current source 110, the control unit 120 including an element having a gain for frequency components of the harmonic current components that are integer multiples of a predetermined frequency, and disabling the element having the gain when the load is in the predetermined driving state. In this case, when the active filter device 100 outputs the fundamental current component when the load is stopped, oscillation in the control of the harmonic current component can be suppressed. From another perspective, the active filter device 100 of the present disclosure includes a load connected to a power source 20, a current source 110 connected to the power source 20 and in parallel with the load, the current source 110 outputting a fundamental current component and a harmonic current component to the power source 20 connected to the load, and a control unit 120 controlling the current output by the current source 110, wherein the control unit 120 disables control of the harmonic current component when the load is in a predetermined driving state. In this case, when the active filter device 100 outputs a fundamental current component when the load is stopped, oscillation in the control of the harmonic current component can be suppressed. Here, the predetermined drive state is a state in which any one of the power of the load, the current flowing through the load, the DC voltage ripple occurring in the load, or the rotation speed of the load is equal to or less than a predetermined value, and in this case, it is possible to suppress oscillation in the control of harmonic current components according to the drive state of the load. The predetermined drive state is a state in which a stop signal for the load is received from an external device, and in this case, oscillation can be suppressed in the control of harmonic current components in response to the external signal. Furthermore, the control unit 120 calculates the fundamental current component and the harmonic current component from the current flowing through the active filter device 100, acquires information about the power source 20, sets a first target value for the fundamental current component based on the acquired information about the power source 20, sets a second target value for the harmonic current component based on the current flowing through the load, and controls the fundamental current component and the harmonic current component based on the first target value and the second target value. In this case, the active filter device 100 can adjust the voltage of the power distribution system. Furthermore, the control unit 120 includes a repetitive control in an element having a gain for frequency components that are integer multiples of the predetermined frequency, and disables the repetitive control when a state value related to driving the load is equal to or less than a predetermined value, thereby improving the performance of compensating for harmonic currents. Furthermore, the control unit 120 controls the fundamental wave current component and the harmonic current component separately, and in this case, control responses can be set separately to obtain control performance according to frequency. Moreover, the load is incorporated into the air conditioner 36. In this case, the active filter device 100 can compensate for harmonic current components generated by the air conditioner 36. The air conditioner 36 of the present disclosure incorporates the active filter device 100 described in claim 1 or 2. In this case, when the active filter device 100 outputs a fundamental current component when the load in the air conditioner 36 is stopped, oscillation in the control of harmonic current components can be suppressed. The air conditioner 36 of the present disclosure includes a plurality of active filter devices 100 according to claim 1 or 2, and the plurality of active filter devices 100 share the responsibility of outputting the fundamental wave current component and the harmonic current component. In this case, the output amount per active filter device 100 can be reduced.

[0060] Although the embodiments have been described above, the technical scope of the present disclosure is not limited to the scope of the above-described embodiments. It is clear from the claims that combinations of two or more of the above-described embodiments, and various modifications or improvements to the above-described embodiments, are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0061] 20... power supply, 60... power converter, 100... active filter device, 110... current source, 120... controller, 150, 170... repetitive controller

Claims

1. A load connected to a power supply, and a power conversion device connected to the power supply and in parallel with the load, a current source that outputs a fundamental current component and a harmonic current component to the power supply connected to the load; a controller for controlling the current output by the current source; Equipped with The controller an element having a gain for a frequency component that is an integer multiple of a predetermined frequency in the harmonic current component; When the driving state of the load is a predetermined driving state, the element having the gain is disabled. Power conversion device.

2. A load connected to a power supply, and a power conversion device connected to the power supply and in parallel with the load, a current source that outputs a fundamental current component and a harmonic current component to the power supply connected to the load; a controller for controlling the current output by the current source; Equipped with The controller When the drive state of the load is a predetermined drive state, the control of the harmonic current component is disabled. Power conversion device.

3. 3. The power conversion device according to claim 1, wherein the predetermined drive state is a state in which any one of a power of the load, a current flowing through the load, a DC voltage ripple occurring in the load, or a rotation speed of the load is equal to or less than a predetermined value.

4. 3. The power conversion device according to claim 1, wherein the predetermined drive state is a state in which a stop signal for the load is received from an external device.

5. The controller calculating the fundamental wave current component and the harmonic current component from the current flowing through the power conversion device; acquiring information about the power source; setting a first target value of the fundamental wave current component based on the acquired information of the power supply; setting a second target value of the harmonic current component based on the current flowing through the load; controlling the fundamental wave current component and the harmonic current component based on the first target value and the second target value; The power conversion device according to claim 1 or 2.

6. The controller a repetitive control is included in the element having a gain for a frequency component that is an integer multiple of the predetermined frequency, and when a state value related to driving the load is equal to or less than a predetermined value, the repetitive control is disabled; The power conversion device according to claim 1 .

7. The controller The fundamental wave current component and the harmonic current component are controlled separately. The power conversion device according to claim 1 or 2.

8. The power conversion device according to claim 1 or 2, wherein the load is incorporated into an air conditioning device.

9. An air conditioner incorporating the power conversion device according to claim 1 or 2.

10. 3. An air conditioner comprising a plurality of power conversion devices according to claim 1 or 2, wherein the plurality of power conversion devices share the responsibility of outputting the fundamental wave current component and the harmonic current component.

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