WO2023067810A1

WO2023067810A1 - Power conversion device, motor drive device, and refrigeration-cycle application apparatus

Info

Publication number: WO2023067810A1
Application number: PCT/JP2021/039142
Authority: WO
Inventors: 翔英堤; 慎也豊留; 和徳畠山
Original assignee: 三菱電機株式会社
Priority date: 2021-10-22
Filing date: 2021-10-22
Publication date: 2023-04-27
Also published as: JPWO2023067810A1; CN118104123A

Abstract

A power conversion device (200) comprises: a rectifier unit (3) for rectifying a first AC power supplied from a commercial power supply (1); a smoothing capacitor (5) connected to the output end of the rectifier unit (3); an inverter (30) connected to both ends of the smoothing capacitor (5) and generating a second AC power to output the second AC power to a motor (7) included in a load; and a control device (100) for controlling the operation of the inverter (30). The control device (100) performs vibration suppression control and load current control, said vibration suppression control reducing the vibration of the motor (7), said load current control performing control so that load current that is the output current of the smoothing capacitor (5) approaches a desired value.

Description

Power conversion device, motor drive device and refrigeration cycle application equipment

The present disclosure relates to a power conversion device, a motor drive device, and a refrigeration cycle application device that convert AC power into desired power.

Conventionally, a device such as a motor control device that controls the operation of a motor reduces noise by appropriately compensating for the torque pulsation component according to the state of the motor that drives a single rotary compressor, twin rotary compressor, etc. It suppresses the occurrence of vibration that is the cause. Such a technique is disclosed in Patent Document 1.

WO2021/059350

However, according to the above-described conventional technology, the torque ripple component is compensated for the purpose of reducing noise and vibration. There is a problem that the charge/discharge current becomes unbalanced between the positive side and the negative side of the power supply current, and the even-order harmonic component may increase.

The present disclosure has been made in view of the above, and an object thereof is to obtain a power conversion device capable of suppressing generation of harmonic components while suppressing generation of vibration in a connected load.

In order to solve the above-described problems and achieve the object, a power conversion device according to the present disclosure includes a rectification unit that rectifies first AC power supplied from a commercial power supply, and a rectification unit that is connected to an output end of the rectification unit. A capacitor, an inverter connected to both ends of the capacitor for generating second AC power and outputting it to a motor included in a load, and a control device for controlling the operation of the inverter. The control device performs vibration suppression control to reduce vibration of the motor and load current control to bring the load current, which is the output current of the capacitor, closer to a desired value.

The power converter according to the present disclosure has the effect of being able to suppress the generation of harmonic components while suppressing the generation of vibrations in the connected load.

1 is a diagram showing a configuration example of a power converter according to Embodiment 1; FIG. FIG. 2 is a diagram showing a configuration example of an inverter included in the power converter according to Embodiment 1; FIG. 2 is a block diagram showing a configuration example of a control device included in the power conversion device according to Embodiment 1; FIG. 3 is a block diagram showing a configuration example of a voltage command value calculation unit included in the control device according to Embodiment 1; 4 is a block diagram showing a configuration example of a load current control section included in the voltage command value calculation section according to the first embodiment; FIG. 4 is a block diagram showing a configuration example of a vibration suppression control compensation value calculation section included in the voltage command value calculation section according to the first embodiment; FIG. FIG. 2 is a block diagram showing a configuration example of a vibration suppression limit control section included in the voltage command value calculation section according to Embodiment 1; FIG. 2 is a block diagram showing a configuration example of a power supply harmonic standard value calculation unit included in the vibration suppression limit control unit according to the first embodiment; FIG. 4 is a block diagram showing a configuration example of an order component calculation section included in the vibration suppression and limitation control section according to Embodiment 1; 4 is a block diagram showing a configuration example of a speed control unit and a vibration suppression control unit included in the voltage command value calculation unit according to the first embodiment; FIG. FIG. 4 shows examples of waveforms of motor torque, load torque, and load current when vibration suppression control is performed to suppress vibration in the power converter according to Embodiment 1; FIG. 4 shows examples of waveforms of motor torque, load torque, and load current when load current control for suppressing power supply harmonics is performed in the power converter according to Embodiment 1; 4 is a flowchart showing the operation of the control device included in the power conversion device according to Embodiment 1; FIG. 2 is a diagram showing an example of a hardware configuration that implements a control device included in the power conversion device according to Embodiment 1; FIG. A diagram showing a configuration example of a refrigeration cycle application device according to Embodiment 2

A power conversion device, a motor drive device, and a refrigeration cycle application device according to an embodiment of the present disclosure will be described below in detail based on the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a power converter 200 according to Embodiment 1. As shown in FIG. FIG. 2 is a diagram showing a configuration example of the inverter 30 included in the power conversion device 200 according to Embodiment 1. As shown in FIG. Power converter 200 is connected to commercial power source 1 and compressor 8 . The power conversion device 200 converts the first AC power of the power supply voltage _Vs supplied from the commercial power supply 1 into the second AC power having desired amplitude and phase, and supplies the second AC power to the compressor 8 . Power converter 200 includes reactor 2 , rectifier 3 , smoothing capacitor 5 , inverter 30 , bus voltage detector 10 , load current detector 40 , and controller 100 . A motor drive device 400 is configured by the power conversion device 200 and the motor 7 included in the compressor 8 .

The commercial power supply 1 is assumed to have a frequency of 50 Hz or 60 Hz, but is not limited to these. Moreover, the commercial power source 1 may be a distributed power source as long as it can output AC power. Reactor 2 is connected between commercial power source 1 and rectifying section 3 . The reactor 2 has a shape such as an EI shape, an EE shape, or the like, in which electromagnetic steel plates or the like are laminated, uses an iron core such as ferrite or amorphous, and has a winding made of copper, aluminum, or the like. The rectifying section 3 has a bridge circuit composed of rectifying elements 131 to 134, rectifies the first AC power of the power supply voltage _Vs supplied from the commercial power supply 1, and outputs it. The rectifier 3 performs full-wave rectification. The rectifying elements 131 to 134 are, for example, diodes, but may be power semiconductors such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

The smoothing capacitor 5 is a smoothing element that is connected to the output terminal of the rectifier 3 and smoothes the power rectified by the rectifier 3 . The smoothing capacitor 5 is, for example, a capacitor such as an electrolytic capacitor or a film capacitor. The smoothing capacitor 5 has a capacity for smoothing the power rectified by the rectifier 3, and the voltage generated in the smoothing capacitor 5 by the smoothing has a DC component rather than a full-wave rectified waveform of the commercial power supply 1. It has a waveform shape in which a voltage ripple corresponding to the frequency of the commercial power supply 1 is superimposed, and does not pulsate greatly. The frequency of this voltage ripple is a two-fold component of the frequency of the power supply voltage _Vs when the commercial power supply 1 is single-phase, and a six-fold component is the main component when the commercial power supply 1 is three-phase. If the power input from commercial power supply 1 and the power output from inverter 30 do not change, the amplitude of this voltage ripple is determined by the capacity of smoothing capacitor 5 . For example, it pulsates in such a range that the maximum value of the voltage ripple generated in the smoothing capacitor 5 is less than twice the minimum value.

The bus voltage detection unit 10 is a detection unit that detects the voltage across the smoothing capacitor 5 , that is, the voltage across the

DC buses

12 a and 12 b as a bus voltage _Vdc , and outputs the detected voltage value to the control device 100 . Load current detection unit 40 is a detection unit that detects load current _Idc , which is a direct current flowing into inverter 30 from smoothing capacitor 5 , and outputs the detected current value to control device 100 .

The inverter 30 is connected across the smoothing capacitor 5 and converts the power output from the rectifier 3 and the smoothing capacitor 5 into second AC power having a desired amplitude and phase, that is, generates the second AC power. and output to the motor 7. Specifically, inverter 30 receives bus voltage _Vdc , generates a three-phase AC voltage with variable frequency and voltage value, and supplies it to motor 7 via output lines 331-333. The inverter 30 includes an inverter main circuit 310 and a drive circuit 350, as shown in FIG. Input terminals of the inverter main circuit 310 are connected to the

DC buses

12a and 12b. The inverter main circuit 310 includes switching elements 311-316. Freewheeling rectifying elements 321 to 326 are connected in anti-parallel to the switching elements 311 to 316, respectively.

The drive circuit 350 generates drive signals Sr1-Sr6 based on PWM (Pulse Width Modulation) signals Sm1-Sm6 output from the control device 100. FIG. The drive circuit 350 controls on/off of the switching elements 311-316 by the drive signals Sr1-Sr6. As a result, the inverter 30 can supply the three-phase AC voltage with variable frequency and variable voltage to the motor 7 via the output lines 331-333.

The PWM signals Sm1 to Sm6 are signals having a logic circuit signal level, that is, a magnitude of 0V to 5V. The PWM signals Sm1 to Sm6 are signals having the ground potential of the control device 100 as a reference potential. On the other hand, the driving signals Sr1 to Sr6 are signals having voltage levels necessary to control the switching elements 311 to 316, eg, -15V to +15V. The drive signals Sr1 to Sr6 are signals having the potential of the negative terminal, that is, the emitter terminal of the corresponding switching elements 311 to 316 as a reference potential.

The compressor 8 is a load having a motor 7 for driving compression. The motor 7 rotates according to the amplitude and phase of the second AC power supplied from the inverter 30 and performs compression operation. For example, when the compressor 8 is a hermetic compressor used in an air conditioner or the like, the load torque of the compressor 8 can often be regarded as a constant torque load. As for the motor 7, FIG. 1 shows a case where the motor windings are Y-connected, but this is an example and is not limited to this. The motor windings of the motor 7 may be delta-connection, or may be switchable between Y-connection and delta-connection. In this embodiment, the compressor 8 is assumed to be a single rotary compressor, a scroll compressor, or the like, but is not limited to these.

In addition, in the power conversion device 200, the arrangement of each configuration shown in FIG. 1 is an example, and the arrangement of each configuration is not limited to the example shown in FIG. For example, the reactor 2 may be arranged after the rectifying section 3 . Further, the power conversion device 200 may include a booster section, or the rectifier section 3 may have the function of the booster section. In the following description, the bus voltage detection section 10 and the load current detection section 40 may be collectively referred to as a detection section. Also, the voltage value detected by the bus voltage detection unit 10 and the current value detected by the load current detection unit 40 may be referred to as detection values.

Control device 100 acquires bus voltage _Vdc from bus voltage detector 10 and load current _Idc from load current detector 40 . Control device 100 controls the operation of inverter main circuit 310, specifically, the on/off of switching elements 311 to 316 included in inverter main circuit 310, using the detection values detected by the respective detection units. In the present embodiment, control device 100 controls the operation of inverter 30 so as to suppress the generation of power source harmonics generated in power conversion device 200 . It should be noted that the control device 100 does not have to use all the detection values acquired from each detection unit, and may perform control using some of the detection values.

The configuration of the control device 100 will be explained. FIG. 3 is a block diagram showing a configuration example of the control device 100 included in the power conversion device 200 according to Embodiment 1. As shown in FIG. The control device 100 includes an operation control section 102 and an inverter control section 110 .

The operation control unit 102 receives command information Q _e from the outside and generates a frequency command value ω _e ^* based on the command information Q _e . The frequency command value ω _e ^* is obtained by multiplying the rotational angular velocity command value ω _m ^* , which is the command value for the rotational speed of the motor 7, by the number of pole pairs P _m of the motor 7, as shown in the following equation (1). be able to.

When controlling an air conditioner as a refrigeration cycle application device, the control device 100 controls the operation of each part of the air conditioner based on the command information _Qe . The command information _Qe includes, for example, a temperature detected by a temperature sensor (not shown), information indicating a set temperature instructed by a remote controller (not shown), operation mode selection information, operation start and operation end instruction information, and the like. is. The operation modes are, for example, heating, cooling, and dehumidification. Note that the operation control unit 102 may be outside the control device 100 . That is, control device 100 may be configured to acquire frequency command value ω _e ^* from the outside.

The inverter control unit 110 includes a current restoration unit 111, a three-phase to two-phase conversion unit 112, an excitation current command value generation unit 113, a voltage command value calculation unit 115, an electric phase calculation unit 116, and a two-to-three phase conversion unit. A section 117 and a PWM signal generation section 118 are provided.

A current restoration unit 111 restores the phase currents i _u , _iv , and i _w flowing through the motor 7 based on the load current I _dc detected by the load current detection unit 40 . Current restoration unit 111 samples load current _Idc detected by load current detection unit 40 at timing determined based on PWM signals Sm1 to Sm6 generated by PWM signal generation unit 118, thereby obtaining phase current i _u , i _v , i _w can be recovered.

The three-phase to two-phase conversion unit 112 converts the phase currents i _u , _iv , and i _w restored by the current restoration unit 111 to the γ-axis using the electric phase θ _e generated by the electric phase calculation unit 116 described later. An excitation current i _γ that is a current and a torque current i _δ that is a δ-axis current, that is, are converted into current values of the γδ-axis.

The excitation current command value generator 113 generates the excitation current command value i _γ ^* in the above-described rotating coordinate system. Specifically, the excitation current command value generation unit 113 obtains the optimum excitation current command value i _γ ^* for driving the motor 7 with the highest efficiency based on the torque current i _δ . Based on the torque current _iδ , the excitation current command value generator 113 generates a current phase at which the output torque _Tm of the motor 7 becomes a specified value or more or a maximum value, that is, the current value becomes a specified value or less or a minimum value. An exciting current command value i _γ ^* that becomes β _m is output. Here, the excitation current command value generator 113 obtains the excitation current command value i _γ ^* based on the torque current i _δ , but this is an example and the present invention is not limited to this. Even _if the excitation current command value generator 113 obtains the excitation current command value i _{γ * based on the excitation current i γ,} ^the frequency command value ω _e ^* , etc., the same effect can be obtained. Further, the excitation current command value generator 113 may determine the excitation current command value i _γ ^* by flux weakening control or the like. In the following description, the exciting current command value may be referred to as the γ-axis current command value.

The voltage command value calculation unit 115 calculates the load current I _dc obtained from the load current detection unit 40, the frequency command value ω _e ^* obtained from the operation control unit 102, and the excitation current i _γ -axis voltage command value V _{γ *} and δ-axis voltage command value _{V δ} ^* are generated based on ^γ and torque current i _δ and excitation current command value i _γ ^* obtained from excitation current command value generation unit 113 . Furthermore, the voltage command value calculation unit 115 calculates the frequency estimated value ω _est based on the γ-axis voltage command value V _γ ^* , the δ-axis voltage command value V _δ ^* , the excitation current i _γ , and the torque current i _δ . to estimate

The electric phase calculation unit 116 calculates the electric phase θ _e by integrating the frequency estimation value ω _est acquired from the voltage command value calculation unit 115 .

Two-to-three phase converter 117 converts γ-axis voltage command value V _γ ^* and δ-axis voltage command value V _δ ^* obtained from voltage command value calculator 115, that is, voltage command values in a two-phase coordinate system, to electrical phase calculation. Using the electric phase θ _e acquired from the unit 116, the three-phase voltage command values V _u ^* , V _v ^* , V _w ^* , which are the output voltage command values in the three-phase coordinate system, are converted.

PWM signal generation unit 118 converts three-phase voltage command values V _u ^* , V _v ^* , V _w ^* obtained from two-to-three phase conversion unit 117 and bus voltage V _dc detected by bus voltage detection unit 10. The comparison generates PWM signals Sm1-Sm6. The PWM signal generator 118 can also stop the motor 7 by not outputting the PWM signals Sm1 to Sm6.

In the present embodiment, control device 100 performs control in a rotating coordinate system having γ and δ axes. In the following description, γ-axis current, δ-axis current, etc. may be referred to as excitation current, torque current, and the like.

The configuration of the voltage command value calculation unit 115 will be described. FIG. 4 is a block diagram showing a configuration example of voltage command value calculation section 115 included in control device 100 according to the first embodiment. Voltage command value calculator 115 includes frequency estimator 501 , speed controller 502 , vibration suppression control compensation value calculator 503 , vibration suppression limit controller 504 , vibration suppression controller 505 , and integral controller 506 . , a mechanical angle phase calculator 507 , a load current controller 508 , an adder 509 ,

subtractors

510 and 511 , a γ-axis current controller 512 , and a δ-axis current controller 513 .

The frequency estimator 501 calculates the frequency of the voltage supplied to the motor 7 based on the excitation current i _γ , the torque current i _δ , the γ-axis voltage command value V _γ ^* , and the δ-axis voltage command value V _δ ^*. is estimated and output as the frequency estimate ω _est .

When the power conversion device 200 outputs the second AC power to the motor 7 of the compressor 8, the speed control unit 502 controls the operation of the inverter 30 so that the rotation speed of the motor 7 reaches a desired rotation speed. constant current load control. Specifically, the speed controller 502 calculates the difference (ω _e ^* −ω _est ) between the frequency command value ω _e ^* and the frequency estimated value ω _est estimated by the frequency estimator 501 . The speed control unit 502 has a proportional term obtained by performing proportional control on the difference (ω _e ^* −ω _est ), and a proportional term obtained by performing integral control on the difference (ω _e ^* −ω _est ). An integral term is added to produce a first torque current command value i _δ ^* that brings the difference (ω _e ^* −ω _est ) closer to zero. By generating the first torque current command value i _δ ^* in this manner, the speed control unit 502 performs control for matching the frequency estimated value ω _est with the frequency command value ω _e ^* .

A vibration suppression control compensation value calculation unit 503 generates a torque current compensation value i _δtrq ^* , which is a vibration suppression control compensation value, so that the output torque _Tm of the motor 7 follows the periodic variation of the load torque _Tl . Specifically, vibration suppression control compensation value calculation section 503 generates torque current compensation value i _δtrq ^* based on frequency estimation value ω _est acquired from frequency estimation section 501 . The torque current compensation value i _δtrq ^* is for suppressing the pulsation component of the estimated frequency value ω _est , especially the pulsation component with the frequency ω _mn . Here, the “pulsation component of the estimated frequency value ω _est , especially the pulsation component with a frequency of ω _mn ” is the pulsation component of the DC quantity, which is a value representing the estimated frequency value ω _est , especially the pulsation frequency of ω _mn . means the pulsating component. Note that m is a parameter related to the amount of direct current, and n is a parameter indicating the load that the motor 7 drives. For example, n is 1 when the load driven by the motor 7 is a single rotary compressor, and 2 when it is a twin rotary compressor. Also, n may be 3 or more.

The vibration suppression limit control unit 504 obtains the load current I _dc obtained from the load current detection unit 40, the excitation current i _γ and the torque current i _δ obtained from the three-phase two-phase conversion unit 112, and the torque current i δ obtained from the γ-axis current control unit 512. Based on the γ-axis voltage command value V _γ ^* and the δ-axis voltage command value V _δ ^* acquired from the δ-axis current control unit 513, the vibration suppression limit torque current command value Δi _δtrqlim ^* is generated.

In order to suppress the vibration generated in the compressor 8, the vibration suppression control unit 505 compensates the output torque _Tm so as to match the load torque of the compressor 8 in the power conversion device 200, thereby suppressing the vibration. I do. Specifically, the vibration suppression control unit 505 controls the first torque current command value i _δ ^* acquired from the speed control unit 502, the torque current compensation value i _δtrq ^* acquired from the vibration suppression control compensation value calculation unit 503, and A second torque current command value i _δ ^*** is generated based on the vibration suppression limit torque current command value Δi _δtrqlim ^* acquired from the vibration suppression limit control section 504 . Vibration suppression control unit 505 can suppress speed pulsation caused by load torque pulsation by compensating first torque current command value i _δ ^* using torque current compensation value i _δtrq ^* .

Integral control section 506 performs integral control on frequency estimation value ω _est acquired from frequency estimating section 501 .

The mechanical angle phase calculation unit 507 multiplies the value obtained by the integral control unit 506 by 1/ _Pm , that is, divides the value obtained by the integral control unit 506 by the pole log number _Pm of the motor 7, Calculate the mechanical angle phase _θm .

The load current control unit 508 performs motor control to reduce pulsation of the load current _Idc , that is, load current control. Specifically, the load current control unit 508 calculates the torque current compensation value i _δlcc based on the load current I _dc obtained from the load current detection unit 40 and the mechanical angle phase θ _m obtained from the mechanical angle phase calculation unit 507. ^* is generated. The load current control unit 508 is configured by, for example, a notch filter.

The addition unit 509 adds the second torque current command value i _δ ^*** generated by the vibration suppression control unit 505 and the torque current compensation value i _δlcc ^* generated by the load current control unit 508, Generate a third torque current command value i _δ ^**** .

Subtraction unit 510 calculates the difference (i _γ ^* −i _γ ) of excitation current i _γ with respect to excitation current command value i _γ ^* .

The subtraction unit 511 calculates the difference (i _δ _**** ⁻ i _δ ) of the torque current i _δ with respect to the third torque current command value i δ ^**** .

The γ-axis current control unit 512 performs a proportional integral operation on the difference (i _γ ^* −i _γ ) calculated by the subtraction unit 510 to bring the difference (i _γ ^* −i _γ ) close to zero. A command value V _γ ^* is generated. The γ-axis current control unit 512 generates the γ-axis voltage command value V _γ ^* in this manner, thereby performing control to match the excitation current i _γ with the excitation current command value i _γ ^* .

A δ-axis current control unit 513 performs a proportional integral operation on the difference (i _δ ^**** -i _δ ) calculated by the subtraction unit 511 to obtain the difference (i _δ ^**** -i _δ ). A δ-axis voltage command value V _δ ^* that approaches zero is generated. By generating the δ-axis voltage command value V _δ ^* in this manner, the δ-axis current control unit 513 controls the torque current i _δ to match the third torque current command value i _δ ^**** . I do.

A configuration of the load current control unit 508 will be described. FIG. 5 is a block diagram showing a configuration example of load current control section 508 included in voltage command value calculation section 115 according to the first embodiment. Load current control section 508 includes multiplication section 521, sine calculation section 522, cosine calculation section 523, low-

pass filters

524 and 525,

subtraction sections

526 and 527,

integration control sections

528 and 529, and sine calculation section 530. , a cosine calculator 531 , and an adder 532 .

The multiplier 521 multiplies the mechanical angle phase _θm by n to calculate the frequency component n× _θm to be controlled.

The sine calculator 522 multiplies the load current I _dc by the sine sin(n×θ _m ) of the frequency component n×θ _m to be controlled. The low-pass filter 524 performs low-pass filtering with a time constant _Tfs , removes the AC component from the calculated value obtained by the sine calculator 522, and extracts the DC component. where s is the Laplacian operator. The subtraction unit 526 calculates the difference between the DC component and 0 so that the DC component obtained by the low-pass filter 524 becomes 0. The integral control unit 528 performs integral control on the difference obtained by the subtraction unit 526 to calculate the sine component of the current command value that brings the difference closer to zero. Sine calculator 530 multiplies the sine component of the current command value calculated by integral controller 528 by sine sin (n×θ _m ) to calculate an AC component in the imaginary axis direction on the complex plane.

The cosine calculator 523 multiplies the load current I _dc by the cosine cos (n×θ _m ) of the frequency component n×θ _m to be controlled. The low-pass filter 525 performs low-pass filtering with a time constant _Tfs , removes AC components from the calculated values obtained by the cosine calculator 523, and extracts DC components. The subtraction unit 527 calculates the difference between the DC component and 0 so that the DC component obtained by the low-pass filter 525 becomes 0. The integral control unit 529 performs integral control on the difference obtained by the subtraction unit 527 to calculate the cosine component of the current command value that brings the difference closer to zero. Cosine calculator 531 multiplies the cosine component of the current command value calculated by integral controller 529 by cosine cos (n×θ _m ) to calculate the AC component in the real axis direction on the complex plane.

The addition unit 532 adds the AC component in the imaginary axis direction on the complex plane calculated by the sine calculation unit 530 and the AC component in the real axis direction on the complex plane calculated by the cosine calculation unit 531, and obtains the mechanical angle A torque current compensation value i _δlcc ^* , which is an alternating quantity due to the n-fold component of the frequency, is generated.

Note that n represents the number of times the load fluctuation occurs in the machine 1f cycle, and for example, n=1 in the case of a single rotary compressor. In particular, when the load connected to the power conversion device 200 is the compressor 8 including the motor 7, at the motor operating frequencies of 0.6 and 1.4 times the power frequency of the commercial power source 1, It is easy to be NG. Therefore, the control device 100 controls the power conversion device 200 so that the 1f component of the mechanical frequency of the current supplied to the motor 7 becomes significant at motor operating frequencies that are 0.6 times and 1.4 times the power frequency of the commercial power source 1. By controlling the operation of , operation that satisfies the power supply harmonic standard is possible. Control device 100 may grasp the power supply frequency of commercial power supply 1 from the value of load current _Idc obtained from load current detection unit 40 and the content of control for inverter 30, or may determine the power supply frequency of commercial power supply 1 to which commercial power supply 1 is connected. In this case, information on the power supply frequency of the commercial power supply 1 may be held in advance. Further, the control device 100 can grasp the mechanical frequency, which is the operating frequency of the motor 7 , from the details of control over the inverter 30 .

The configuration of the vibration suppression control compensation value calculation unit 503 will be described. FIG. 6 is a block diagram showing a configuration example of vibration suppression control compensation value calculation section 503 included in voltage command value calculation section 115 according to the first embodiment. The vibration suppression control compensation value calculation unit 503 includes a calculation unit 550, a cosine calculation unit 551, a sine calculation unit 552,

multiplication units

553 and 554, low-

pass filters

555 and 556,

subtraction units

557 and 558, and a frequency control unit. It includes

sections

559 and 560 ,

multiplication sections

561 and 562 , and an addition section 563 .

The calculation unit 550 integrates the estimated frequency value ω _est and divides it by the pole logarithm to calculate the mechanical angle phase θ _mn indicating the rotational position of the motor 7 . A cosine calculator 551 calculates a cosine cos θ _mn based on the mechanical angle phase θ _mn . A sine calculator 552 calculates a sine sin θ _mn based on the mechanical angle phase θ _mn .

The multiplier 553 multiplies the estimated frequency value ω _est by the cosine cos θ _mn to calculate the cosine component ω _est ·cos θ _mn of the estimated frequency value ω _est . The multiplier 554 multiplies the frequency estimation value ω _est by the sine sin θ _mn to calculate the sine component ω _est ·sin θ _mn of the frequency estimation value ω _est . The cosine component ω _est ·cos θ _mn and the sine component ω _est ·sin θ _mn calculated by the

multipliers

553 and 554 include a pulsation component with a frequency of ω _mn and a pulsation component with a frequency higher than ω _mn . Contains harmonic components.

The low-

pass filters

555 and 556 are first-order lag filters whose transfer function is represented by 1/(1+s·T _f ). T _f is a time constant and is determined to remove pulsation components with frequencies higher than the frequency ω _mn . Note that "removal" includes the case where part of the pulsation component is attenuated, that is, reduced. The time constant _Tf is set by the operation control unit 102 based on the speed command value, and may be notified to the low-

pass filters

555 and 556 by the operation control unit 102, or may be held by the low-

pass filters

555 and 556. good. As for the low-

pass filters

555 and 556, a first-order lag filter is an example, and a moving average filter or the like may be used, and the type of filter is not limited as long as the pulsation component on the high frequency side can be removed.

A low-pass filter 555 performs low-pass filtering on the cosine component ω _est ·cos θ _mn to remove pulsation components with a frequency higher than ω _mn and outputs a low frequency component ω _estcos . The low-frequency component ω _estcos is a DC quantity representing a cosine component with a frequency ω _mn among the pulsating components of the frequency estimate ω _est .

A low-pass filter 556 performs low-pass filtering on the sine component ω _est ·sin θ _mn to remove pulsation components with a frequency higher than the frequency ω _mn and outputs a low frequency component ω _estsin . The low-frequency component ω _estsin is a DC quantity representing a sinusoidal component with a frequency ω _mn among the pulsating components of the frequency estimation value ω _est .

The subtraction unit 557 calculates the difference (ω _estcos −0) between the low frequency component ω _estcos output from the low-

pass filter

555 and 0. The subtraction unit 558 calculates the difference (ω _estsin −0) between the low frequency component ω _estsin output from the low-

pass filter

556 and 0.

A frequency control unit 559 performs a proportional integral operation on the difference (ω _estcos −0) calculated by the subtraction unit 557 to generate a cosine component i _δtrqcos of the current command value that makes the difference (ω _estcos −0) close to zero. calculate. By generating the cosine component i _δtrqcos in this manner, the frequency control unit 559 performs control to match the low frequency component ω _estcos to zero.

The frequency control unit 560 performs a proportional integral operation on the difference (ω _estsin −0) calculated by the subtraction unit 558 to generate a sine component i _δtrqsin of the current command value that makes the difference (ω _estsin −0) close to zero. calculate. The frequency control unit 560 generates the sine component i _δtrqsin in this way, thereby performing control to match the low frequency component ω _estsin to zero.

The multiplier 561 multiplies the cosine component i _δtrqcos output from the frequency control unit 559 by the cosine cos θ _mn to generate i _δtrqcos ·cos θ _mn . i _δtrqcos ·cos θ _mn is the AC component with frequency n·ω _est .

The multiplier 562 multiplies the sine component i _δtrqsin output from the frequency control unit 560 by the sine sin θ _mn to generate i _δtrqsin ·sin θ _mn . i _δtrqsin ·sin θ _mn is the AC component with frequency n·ω _est .

The addition unit 563 obtains the sum of i _δtrqcos ·cos θ _mn output from the multiplication unit 561 and i _δtrqsin ·sin θ _mn output from the multiplication unit 562 . The vibration suppression control compensation value calculator 503 outputs the value obtained by the adder 563 as the torque current compensation value i _δtrq ^* .

The vibration suppression control unit 505 adds the torque current compensation value i _δtrq ^* obtained as described above in the vibration suppression control compensation value calculation unit 503 to the torque current command value during calculation, and converts the addition result to the corrected torque current command value. By using it as the second torque current command value i _δ ^*** , the ripple component can be suppressed.

The configuration of the vibration suppression limit control unit 504 will be described. FIG. 7 is a block diagram showing a configuration example of vibration suppression limit control section 504 included in voltage command value calculation section 115 according to the first embodiment. Vibration suppression limit control section 504 includes power harmonic standard value calculation section 601 , order component calculation section 602 , subtraction section 603 , integration control section 604 , and setting section 605 .

The power harmonic standard value calculation unit 601 calculates the power harmonic standard value for each order of the power harmonic. FIG. 8 is a block diagram showing a configuration example of power supply harmonic standard value calculation section 601 included in vibration suppression limit control section 504 according to the first embodiment. The power harmonic standard value calculator 601 includes a power calculator 611 , a power multiplier 612 , a limit value converter 613 , and a coefficient multiplier 614 .

Power calculation unit 611 uses γ-axis voltage command value V _γ ^* , δ-axis voltage command value V _δ ^* , excitation current i _γ , and torque current i _δ to calculate γ-axis voltage command value V _γ ^* × excitation current i The electric power W is calculated by the formula of _γ + δ-axis voltage command value V _δ ^* × torque current i _δ .

The power multiplier 612 calculates the power exceeding the specified 600 watts from the power W as (W-600), and multiplies the calculated value by the second term of the maximum allowable harmonic current specified for each order. . 600 watts is a value specified in JIS (Japanese Industrial Standards) C 61000-3-2. In the example of FIG. 8, "1.08+0.00033" is the maximum allowable harmonic current when the order of power supply harmonics is 2, so the power multiplier 612 outputs "1.08+0.00033 (W-600)". Calculate as The power multiplier 612 performs similar calculations for other orders of power supply harmonics.

The limit value conversion unit 613 multiplies the value of each order obtained by the power multiplication unit 612 by (230/power supply voltage) to calculate the limit value for each order. Note that 230 is the value when the power supply is single-phase, as specified in the aforementioned JIS C 61000-3-2. The power supply voltage is 100V or 200V in a general usage environment.

A coefficient multiplier 614 multiplies a coefficient K of 0<K≤1 to set a margin for the limit value for each order obtained by the limit value conversion unit 613, and obtains a power supply harmonic for each order in power supply harmonics. Obtain harmonic specifications. For example, when k=0.5, a margin of 50% is given to the standard value of power harmonics, and when k=1, no margin is given to the standard value of power harmonics. be.

Returning to the description of FIG. The order component calculation unit 602 calculates each order component of the power supply harmonic using the load current _Idc . FIG. 9 is a block diagram showing a configuration example of the order component calculation section 602 included in the vibration suppression/limitation control section 504 according to the first embodiment. The order component calculation unit 602 includes

multiplication units

621 and 622, low-

pass filters

623 and 624, a peak value calculation unit 625, an effective value calculation unit 626, a squaring unit 627,

division units

628 and 629, and an addition unit. 630 and a 1/2 power part 631 . Here, for each order of the power source harmonics, the order component calculation unit 602 does not target only the integer values, but targets the entire range by cooperating with the orders before and after. The order component calculation unit 602, for example, targets the 1.5th to 2.5th orders when targeting the second order, and targets the 2.5th to 3.5th orders when targeting the third order. . Specifically, when the power supply frequency of the commercial power supply 1 is 50 Hz, the order component calculation unit 602 performs calculation in units of 5 Hz in the range from 75 Hz to 125 Hz when the order is second order. Therefore, order component calculation section 602 performs

multiplication sections

621 and 622, low-

pass filters

623 and 624, peak value calculation section 625, and effective value calculation section 626 as follows: Be prepared for a few minutes.

The multiplier 621 multiplies the load current _Idc by the cosine cos _θx of the frequency component _θx to be calculated. The multiplier 622 multiplies the load current I _dc by the sine sin θ _x of the frequency component θ _x to be calculated. A low-pass filter 623 removes the AC component from the calculated value obtained by the multiplier 621 and extracts the DC component. A low-pass filter 624 removes the AC component from the calculated value obtained by the multiplier 622 and extracts the DC component. The peak value calculator 625 uses _Idccosx obtained from the lowpass filter 623 and _Idcsinx obtained from the lowpass filter 624 to calculate the peak value of the frequency component _θx to be calculated. The effective value calculator 626 divides the peak value of the frequency component _θx to be calculated obtained by the peak value calculator 625 by √(2) to obtain the effective value of the frequency component _θx to be calculated. Calculate. √(2) represents the square root of two.

The squaring unit 627 squares the effective value calculated at each frequency of the order to be calculated. In FIG. 9, the minimum frequency among the frequency components is (n-1). The maximum frequency is n. It is described as fifth order. For example, when the order is 2, the minimum frequency is 1.5 and the maximum frequency is 2.5. Here, among the frequency components to be calculated for each order, the minimum frequency is the same as the maximum frequency of the next lower order, and the maximum frequency is the same as the minimum frequency of the one higher order. A division unit 628 halves the square value of the effective value of the minimum frequency obtained by the squaring unit 627 in order to eliminate the influence of overlapping portions. A division unit 629 halves the square value of the effective value of the maximum frequency obtained by the squaring unit 627 in order to eliminate the influence of overlapping portions. Adder 630 obtains a total value by adding the values obtained by squaring the effective values calculated at each frequency of the order to be calculated, or the values obtained by halving the squared values. A 1/2 power unit 631 takes the square root of the total value obtained by the addition unit 630 to obtain the magnitude of the order component to be calculated. The order component calculation unit 602 performs similar calculations for each order.

Return to the description of Fig. 7. The subtraction unit 603 calculates the power harmonic standard value tolerance. Specifically, the subtraction unit 603 subtracts the power harmonic standard value calculated by the power harmonic standard value calculation unit 601 and the power harmonic order component calculated by the order component calculation unit 602 for each order. Compute the difference. The subtraction unit 603 outputs the calculated difference to the integration control unit 604 as the power supply harmonic standard value tolerance.

The integral control unit 604 performs integral control on the power supply harmonic standard value tolerance calculated by the subtraction unit 603 to bring the difference closer to 0. That is, the order component of the power supply harmonic calculated by the order component calculation unit 602 to the power harmonic standard value calculated by the power harmonic standard value calculation unit 601, the current value _idck is calculated.

The setting unit 605 sets the vibration suppression limit torque current command value Δi _δtrqlim ^* depending on whether the current value i _dck calculated by the integral control unit 604 is 0 or more or less than 0. Specifically, the setting unit 605 sets the vibration suppression limit torque current command value Δi _δtrqlim ^* as shown in Equation (2).

The configurations of the speed control unit 502 and the vibration suppression control unit 505 will be described. FIG. 10 is a block diagram showing a configuration example of speed control unit 502 and vibration suppression control unit 505 included in voltage command value calculation unit 115 according to the first embodiment. The speed control section 502 includes a subtraction section 711 , a proportional control section 712 , an integral control section 713 and an addition section 714 . The vibration suppression control section 505 includes an adder section 721 , a limiter section 722 , a subtractor section 726 , an adder section 727 , a limiter 728 and an adder section 729 . The limiting section 722 includes a storage section 723 , a selecting section 724 and a limiter 725 .

In speed control section 502, subtraction section 711 calculates the difference (ω _e ^* - ω _est ) between frequency command value ω _e ^* and frequency estimated value ω _est estimated by frequency estimating section 501 . Proportional control section 712 performs proportional control on the difference (ω _e ^* - ω _est ) between frequency command value ω _e ^* and frequency estimated value ω _est obtained from subtraction section 711, and converts proportional term i _δp ^* to Output. Integral control section 713 performs integral control on the difference (ω _e ^* - ω _est ) between frequency command value ω _e ^* and frequency estimated value ω _est obtained from subtraction section 711, and converts integral term i _δi ^* to Output. The addition unit 714 adds the proportional term i _δp ^* obtained from the proportional control unit 712 and the integral term i _δi ^* obtained from the integral control unit 713 to generate the first torque current command value i _δ ^* . .

In the vibration suppression control unit 505, an addition unit 721 adds the first torque current command value i _δ ^* generated by the speed control unit 502 and the torque current compensation value i _δtrq ^* obtained from the vibration suppression control compensation value calculation unit 503. are added to generate the intermediate torque current command value i _δ ^** .

A limiter 722 sets a limit value for the intermediate torque current command value i _δ ^** . Generally, in the power converter 200 that controls the refrigerating cycle equipment, a limit value is set for the intermediate torque current command value i _δ ^** for the purpose of vibration suppression control and the like. In the present embodiment, vibration suppression control section 505 uses δ-axis current limit values i _δlim1 , i _δlim2 , and i _δtrqlim as limit values for intermediate torque current command value i _δ ^** . The δ-axis current limit value i _δlim1 can be expressed by Equation (3), the δ-axis current limit value i _δlim2 can be expressed by Equation (4), and the δ-axis current limit value i _δtrqlim can be expressed by Equation (5). be able to.

The δ-axis current limit value i _δlim2 is based on the assumption that the limit is applied based on the voltage value of the motor 7 when the rotation speed of the motor 7 is in the medium-to-high speed range. In equation (4), L _γ is the γ-axis inductance and L _δ is the δ-axis inductance. In general, the maximum AC voltage that the inverter ₃₀ can output to the motor ₇ is _limited . , is expressed as in equation (6). Note that the limit value V _om may be a value obtained by subtracting, for example, the winding resistance of the motor 7, the voltage drop of the switching elements 311 to 316 of the inverter 30, and the like. Strictly speaking, the output limit range of the inverter 30 has a hexagonal shape, but is approximated by a circle here. In the present embodiment, the discussion is based on the premise that the approximation is by a circle, but it is needless to say that the discussion may be made strictly considering a hexagon.

Solving equation (6) for the torque current i _δ yields equation (4). The δ-axis current command value in equation (4) can take into consideration the voltage limit and the effectiveness of the flux-weakening control. The δ-axis current limit value i _δlim2 is a voltage limit value that is a limit value V _om based on the voltage that the inverter 30 can output to the motor 7, an electrical angular velocity ω _e that is the rotation speed of the motor 7, and a γδ-axis magnetic flux chain of the motor 7. It is determined from the alternating number Φ _a , the γ-axis inductance L _γ , and the δ-axis inductance L _δ .

In FIG. 10, the storage unit 723 of the limiting unit 722 stores δ-axis current limit values i _δlim1 and i _δlim2 . That is, the limiter 722 has δ-axis current limit values i _δlim1 and i _δlim2 . The selection unit 724 selects one of the δ-axis current limit values i _δlim1 and i _δlim2 stored in the storage unit 723 and outputs it as the δ-axis current limit value i _δlim . The δ-axis current limit value i _δlim is a current limit value for the intermediate torque current command value i _δ ^** . A limiter 725 limits the intermediate torque current command value i _δ ^** with the δ-axis current limit value i _δlim and outputs it as a limit torque current command value i _δlim ^* . Note that the limiting unit 722 may store the δ-axis current limit values i _δlim1 and i _δlim2 calculated by itself in the storage unit 723, or may acquire them from the outside, for example, the operation control unit 102. may be stored in the storage unit 723.

The subtractor 726 calculates the difference between the δ-axis current limit value i _δlim obtained from the limiter 722 and the limit torque current command value i _δlim ^* . When the limiter 725 limits within the range of the δ-axis current limit value i _δlim , i _δ ^** ≧i _δlim ≧i _δlim ^* . Since there are cases where the limiter 725 does not use up the δ-axis current limit value i _δlim , the unused portion is calculated as the difference between the δ-axis current limit value i _δlim and the limit torque current command value i _δlim ^* . The adder 727 adds the difference calculated by the subtractor 726 and the vibration suppression limit torque current command value Δi _δtrqlim ^* calculated by the vibration suppression limit control unit 504, and calculates the δ axis for the torque current compensation value i _δtrq ^* . A current limit value i _δtrqlim is calculated. A limiter 728 limits the torque current compensation value i _δtrq ^* with the δ axis current limit value i _δtrqlim and outputs it as the post-limiting torque current compensation value i _δtrqlim ^* . The adder 729 adds the limited torque current command value i _δlim ^* and the post-limiter torque current compensation value i _δtrqlim ^* to generate the second torque current command value I _δ ^*** .

Based on the configuration and control details that have been described in detail up to this point, the effects obtained in this embodiment will be described. In the power conversion device 200 shown in FIG. 1, the load connected to both ends of the smoothing capacitor 5 includes, for example, a load composed of the inverter 30 and the motor 7, etc. Here, pulsation occurs periodically. Assume the connection of such loads. In a device in which a large pulsation occurs once in one cycle of the mechanical angle of the motor 7, it is necessary to prevent vibration of the device and noise caused by the vibration. Constraint control, or machine 1f compensation, is widely used. Vibration suppression control is control that suppresses speed unevenness that causes vibration by causing the output torque _Tm to follow the pulsating load torque. The machine 1f represents the one-fold component of the machine frequency, which is the operating frequency of the motor 7. FIG.

FIG. 11 is a diagram showing examples of waveforms of the motor torque, the load torque, and the load current _Idc when vibration suppression control for suppressing vibration is performed in the power conversion device 200 according to the first embodiment. . In FIG. 11, the upper part shows the waveforms of the motor torque and the load torque, and the lower part shows the waveform of the load current _Idc . Note that each horizontal axis indicates time. In the example of FIG. 11, it can be seen that the motor torque follows the load torque. As a feature at this time, as shown in the lower part of FIG. 11, a phenomenon occurs in which the load current _Idc generated on the power supply side is unbalanced between positive and negative. In other words, by performing vibration suppression control by the control device 100, while the effect of suppressing vibration can be obtained, the pulsation of the mechanical 1f component of the load current _Idc on the power supply side becomes large, and it conforms to the power supply harmonic standard. It means that there is a possibility that it will not. Since the use of equipment that does not conform to the standards is not permitted, power supply harmonics must also be suppressed. Here, in the control device 100, it is conceivable to suppress the harmonics by turning off the vibration suppression control. It is desirable to select a method that gradually switches control without

FIG. 12 is a diagram showing examples of waveforms of motor torque, load torque, and load current _Idc when load current control for suppressing power source harmonics is performed in power converter 200 according to Embodiment 1. is. In FIG. 12, the upper part shows the waveforms of the motor torque and the load torque, and the lower part shows the waveform of the load current _Idc . Note that each horizontal axis indicates time. The principle behind the increase _in power supply harmonics is that the load current _Idc is positively and negatively unbalanced. Therefore, as shown in the lower waveform of FIG. If there is, it can be said that the power supply harmonics can be suppressed. At this time, when looking at the waveforms of the motor torque and the load torque in the upper part of FIG. 12, it can be seen that the motor torque has a lagging phase with a small amplitude with respect to the load torque, compared to FIG. Therefore, the load current control is to add a compensation amount to the torque current that generates the motor torque so that the amplitude of the motor torque is small and the phase is delayed. not. The present embodiment includes a vibration suppression control compensation value calculator 503 that generates a torque current compensation value i _δtrq ^* that gradually shifts the amplitude and phase of the motor torque.

Here, if the inertia of the motor 7 is sufficiently large, reducing the torque amplitude also reduces the instantaneous power amplitude of the power consumed by the motor 7. Therefore, the control device 100 controls this instantaneous power. You may make it As a method for gradually shifting the amplitude and phase of the motor torque, the control device 100 is provided with an arithmetic unit for calculating the difference between the above-mentioned power supply harmonic standard value and the order component, and the order component is the power supply harmonic standard value. can be achieved by using the vibration suppression limit control unit 504 that operates the load current control in a range exceeding . By performing control as in this embodiment, there is no need to change the circuit constants of the converter circuit, the switching method, etc., to solve the problem of conforming to harmonic standards. It is possible to obtain a power conversion device 200 with a small load, low cost, and high reliability.

In this manner, the control device 100 performs vibration suppression control for reducing vibration of the motor 7 and load current control for controlling the load current _Idc , which is the output current of the smoothing capacitor 5, to approach a desired value. As load current control, the control device 100 controls the voltage output from the inverter 30 so that the absolute value of the difference between the positive and negative peak values of the instantaneous power consumed by the motor 7 becomes small. Such control is the same as the control device 100 controlling the voltage output from the inverter 30 so that the peak-to-peak value of the positive and negative peaks of the instantaneous power consumed by the motor 7 becomes small. As load current control, the control device 100 controls the load torque generated by the load so that the absolute value of the difference between the positive and negative peak values of the motor torque generated by the motor 7 is small and the phase of the positive peak is the delayed phase. It can also be said that the voltage output from the inverter 30 is controlled so that

The operation of the control device 100 will be explained using a flowchart. FIG. 13 is a flowchart showing the operation of the control device 100 included in the power conversion device 200 according to Embodiment 1. FIG. In the control device 100, the speed control unit 502 generates a first torque current command value i _δ ^* for constant current load control (step S1). The vibration suppression control compensation value calculation unit 503 generates a torque current compensation value i _δtrq ^* , which is a vibration suppression control compensation value, so that the output torque _Tm of the motor 7 follows the periodic fluctuation of the load torque _Tl (step S2). The vibration suppression limit control unit 504 generates a vibration suppression limit torque current command value Δi _δtrqlim ^* (step S3). Vibration suppression control unit 505 generates second torque current command value i δ based on first torque current command value i _δ ^* , torque current compensation value i _δtrq ^* , and vibration suppression limit torque current command value _Δi _δtrqlim ^*. ^*** is generated (step S4). The load current control unit 508 generates the torque current compensation value i _δlcc ^* based on the load current I _dc and the mechanical angle phase θ _m (step S5). The adder 509 adds the second torque current command value i _δ ^*** and the torque current compensation value i _δlcc ^* to generate the third torque current command value i _δ ^**** (step S6). .

Next, the hardware configuration of the control device 100 included in the power conversion device 200 will be described. FIG. 14 is a diagram showing an example of a hardware configuration that implements the control device 100 included in the power conversion device 200 according to Embodiment 1. As shown in FIG. Control device 100 is implemented by processor 91 and memory 92 .

The processor 91 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, DSP (Digital Signal Processor)), or a system LSI (Large Scale Integration). The memory 92 is a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory) or a volatile non-volatile Read Only memory. A semiconductor memory can be exemplified. Moreover, the memory 92 is not limited to these, and may be a magnetic disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

As described above, according to the present embodiment, in power conversion device 200, control device 100 performs vibration suppression control to reduce vibration of motor 7 and load current _Idc , which is the output current of smoothing capacitor 5, to A load current is controlled so as to approach a desired value. Control device 100 adjusts each control content of vibration suppression control and load current control according to the operating state of inverter 30 that outputs the second AC power to motor 7 , that is, the control content for inverter 30 . As a result, the power conversion device 200 can suppress the generation of harmonic components while suppressing the generation of vibrations in the load such as the motor 7 connected thereto.

In the power conversion device 200, the control device 100 uses the γ-axis current, which is a reactive current, instead of the δ-axis current, which is an active current, and utilizes the change in active power due to the winding resistance of the motor 7 to convert the inverter By controlling the load current _Idc , which is the direct current flowing into the circuit 30, to approach a specified value, that is, a constant value, the same effects as in the present embodiment can be obtained. The same applies to subsequent embodiments.

Embodiment 2.
FIG. 15 is a diagram showing a configuration example of a refrigeration cycle device 900 according to Embodiment 2. As shown in FIG. A refrigerating cycle applied equipment 900 according to the second embodiment includes the power converter 200 described in the first embodiment. The refrigerating cycle applied equipment 900 according to Embodiment 2 can be applied to products equipped with a refrigerating cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. In FIG. 15, constituent elements having functions similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment.

Refrigerating cycle applied equipment 900 includes compressor 8 incorporating motor 7 in Embodiment 1, four-way valve 902, indoor heat exchanger 906, expansion valve 908, and outdoor heat exchanger 910 with refrigerant pipe 912. attached through

A compression mechanism 904 for compressing refrigerant and a motor 7 for operating the compression mechanism 904 are provided inside the compressor 8 .

The refrigeration cycle applied equipment 900 can perform heating operation or cooling operation by switching operation of the four-way valve 902 . Compression mechanism 904 is driven by motor 7 whose speed is controlled.

During heating operation, as indicated by solid line arrows, the refrigerant is pressurized by the compression mechanism 904 and sent out through the four-way valve 902, the indoor heat exchanger 906, the expansion valve 908, the outdoor heat exchanger 910, and the four-way valve 902. Return to compression mechanism 904 .

During cooling operation, as indicated by dashed arrows, the refrigerant is pressurized by the compression mechanism 904 and sent through the four-way valve 902, the outdoor heat exchanger 910, the expansion valve 908, the indoor heat exchanger 906, and the four-way valve 902. Return to compression mechanism 904 .

During heating operation, the indoor heat exchanger 906 acts as a condenser to release heat, and the outdoor heat exchanger 910 acts as an evaporator to absorb heat. During cooling operation, the outdoor heat exchanger 910 acts as a condenser to release heat, and the indoor heat exchanger 906 acts as an evaporator to absorb heat. The expansion valve 908 reduces the pressure of the refrigerant to expand it.

The configurations shown in the above embodiments are only examples, and can be combined with other known techniques, or can be combined with other embodiments, without departing from the scope of the invention. It is also possible to omit or change part of the configuration.

1 commercial power supply, 2 reactor, 3 rectifier, 5 smoothing capacitor, 7 motor, 8 compressor, 10 bus voltage detector, 12a, 12b DC bus, 30 inverter, 40 load current detector, 100 controller, 102 operation control section, 110 inverter control section, 111 current restoration section, 112 three-phase to two-phase conversion section, 113 excitation current command value generation section, 115 voltage command value calculation section, 116 electrical phase calculation section, 117 two-phase to three-phase conversion section, 118 PWM signal generator, 131 to 134, 321 to 326 rectifying element, 200 power converter, 310 inverter main circuit, 311 to 316 switching element, 331 to 333 output line, 350 drive circuit, 400 motor drive, 501 frequency estimator , 502 speed control section, 503 vibration suppression control compensation value calculation section, 504 vibration suppression limit control section, 505 vibration suppression control section, 506, 528, 529, 604, 713 integral control section, 507 mechanical angle phase calculation section, 508 load Current control unit, 509, 532, 563, 630, 714, 721, 727, 729 Addition unit, 510, 511, 526, 527, 557, 558, 603, 711, 726 Subtraction unit, 512 γ-axis current control unit, 513 δ-axis current control unit, 521, 553, 554, 561, 562, 621, 622; multiplication unit; 522, 530, 552; sine calculation unit; 523, 531, 551; 624 low-pass filter, 550 calculation unit, 559, 560 frequency control unit, 601 power harmonic standard value calculation unit, 602 order component calculation unit, 605 setting unit, 611 power calculation unit, 612 power multiplication unit, 613 limit value conversion unit, 614 coefficient multiplication unit, 625 peak value calculation unit, 626 effective value calculation unit, 627 squaring unit, 628, 629 division unit, 631 1/2 power unit, 712 proportional control unit, 722 limiting unit, 723 storage unit, 724 selection Parts, 725, 728 Limiters, 900 Refrigeration cycle application equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 Expansion valve, 910 Outdoor heat exchanger, 912 Refrigerant piping.

Claims

a rectifier that rectifies first AC power supplied from a commercial power supply;
a capacitor connected to the output terminal of the rectifying unit;
an inverter connected to both ends of the capacitor for generating second AC power and outputting it to a motor included in the load;
a control device that controls the operation of the inverter;
with
The control device performs vibration suppression control for reducing vibration of the motor and load current control for controlling the load current, which is the output current of the capacitor, to approach a desired value.
Power converter.
As the load current control, the control device controls the voltage output from the inverter so that the absolute value of the difference between the positive and negative peak values of the instantaneous power consumed by the motor becomes small.
The power converter according to claim 1.
As the load current control, the control device is configured such that the absolute value of the difference between the positive and negative peak values of the motor torque generated by the motor is small and the phase of the positive peak is delayed with respect to the load torque generated by the load. controlling the voltage output by the inverter so as to be in phase;
The power converter according to claim 1 or 2.
A motor drive device comprising the power conversion device according to any one of claims 1 to 3.
A refrigerating cycle application device comprising the power conversion device according to any one of claims 1 to 3.