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

Abstract

A power conversion device (200) comprises: a rectification unit (3) that rectifies first AC power supplied from a commercial power source (1); a smoothing capacitor (5) connected to the output end of the rectification unit (3); an inverter (30) which is connected to both ends of the smoothing capacitor (5) and which generates and outputs second AC power to a motor (7); and a control device (100) that controls the operation of the inverter (30) to control the rotation speed of the motor (7), wherein the control device (100) implements a reduction control to reduce a pulsation component generated due to the influence of the dead time of a switching element provided in the inverter (30) and the induced voltage distortion of the motor (7), said pulsation component being superimposed on the three-phase current that is outputted from the inverter (30) to the motor (7).

Description

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

[0001] The present disclosure relates to a power conversion device that converts AC power into desired power, a motor drive device, and a refrigeration cycle device.

[0002] Conventionally, in power conversion devices that control inverter switching and motor drive, harmonic components are generated due to the influence of the operation of the inverter, motor, etc. When the influence of harmonic components is included in measured values ​​such as current values ​​and voltage values, or estimated motor position, it becomes difficult for the power conversion device to perform highly accurate control. In response to this problem, Patent Document 1 discloses a technology for reducing the sixth spatial harmonics generated during motor operation.

[0003] JP 2013-255314 A

[0004] However, the above-mentioned conventional technology only targets sixth-order space harmonics that occur during motor operation. In motor control, an electrical 6f component, which is a pulsating component six times the power supply frequency, is superimposed on the d-axis current and q-axis current represented in a dq rotating coordinate system that rotates in synchronization with the motor rotor position. However, there are various factors that can cause the electrical 6f component to be superimposed on the d-axis current and q-axis current. Therefore, there is a problem that the control using the above-mentioned conventional technology alone is not sufficient.

[0005] The present disclosure has been made in view of the above, and has an object to provide a power conversion device that can reduce pulsating components caused by an inverter and a motor.

[0006] In order to solve the above-mentioned problems and achieve the object, a power conversion device according to the present disclosure includes a rectifier that rectifies first AC power supplied from a commercial power source, a capacitor connected to an output terminal of the rectifier, an inverter connected across the capacitor to generate second AC power and output the second AC power to a motor, and a control device that controls the operation of the inverter to control the rotation speed of the motor. The control device performs reduction control to reduce pulsating components that are superimposed on the three-phase current output from the inverter to the motor and are generated due to the effects of dead time of switching elements provided in the inverter and induced voltage distortion of the motor.

[0007] The power conversion device according to the present disclosure has an effect of being able to reduce pulsating components caused by the inverter and the motor.

[0008] FIG. 1 is a diagram showing a configuration example of a power conversion device according to embodiment 1. FIG. 1 is a diagram showing a configuration example of an inverter provided in the power conversion device according to embodiment 1. Block diagram showing a configuration example of a control device provided in the power conversion device according to embodiment 1. Block diagram showing a configuration example of a voltage command value calculation unit provided in the control device of the power conversion device according to embodiment 1. Block diagram showing a configuration example of a d-axis current control unit provided in the voltage command value calculation unit of the control device in the power conversion device according to embodiment 1. Block diagram showing a configuration example of a q-axis current control unit provided in the voltage command value calculation unit of the control device in the power conversion device according to embodiment 1. FIG. 2 is a diagram showing, as a comparative example, an example of an operating state of the power conversion device when the control device of the power conversion device according to embodiment 1 does not perform reduction control to reduce pulsation of the electrical 6f component included in the current. FIG. 1 shows an example of an operating state of a power conversion device when a control device of the power conversion device of embodiment 1 performs reduction control to reduce pulsation of the electrical 6f component contained in the d-axis current and the q-axis current. FIG. 2 shows an example of an operating state of a power conversion device when a control device of the power conversion device of embodiment 1 performs reduction control to reduce pulsation of the electrical 6f component contained in the d-axis current and the q-axis current. FIG. 3 shows an example of a hardware configuration for realizing the control device provided in the power conversion device of embodiment 1. FIG. 4 shows an example of a configuration of a voltage command value calculation unit provided in the control device of the power conversion device of embodiment 2. FIG. 5 shows an example of a configuration of a d-axis current control unit provided in the voltage command value calculation unit of the control device in the power conversion device of embodiment 2. FIG. 6 shows an example of a configuration of a q-axis current control unit provided in the voltage command value calculation unit of the control device in the power conversion device of embodiment 2.

[0009] Hereinafter, a power conversion device, a motor drive device, and a refrigeration cycle applied device according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] First Embodiment Fig. 1 is a diagram showing a configuration example of a power conversion device 200 according to the first embodiment. Fig. 2 is a diagram showing a configuration example of an inverter 30 included in the power conversion device 200 according to the first embodiment. The power conversion device 200 is connected to a commercial power supply 1 and a motor 7. The power conversion device 200 converts first AC power of a power supply voltage Vs supplied from the commercial power supply 1 into second AC power having a desired amplitude and phase, and supplies the second AC power to the motor 7. The power conversion device 200 includes a reactor 2, a rectifier 3, a smoothing capacitor 5, an inverter 30, a bus voltage detection unit 10, a load current detection unit 40, and a control device 100. The power conversion device 200 and the motor 7 form a motor drive device 400.

[0011] The reactor 2 is connected between the commercial power supply 1 and the rectifier 3. The rectifier 3 has a bridge circuit formed by rectifier elements 131 to 134, and rectifies and outputs the first AC power of the power supply voltage Vs supplied from the commercial power supply 1. The rectifier 3 performs full-wave rectification.

[0012] Smoothing capacitor 5 is a smoothing element connected to the output terminal of rectifier 3 and smoothing the power rectified by rectifier 3. Smoothing capacitor 5 is, for example, an electrolytic capacitor, a film capacitor, or other capacitor. Smoothing capacitor 5 has a capacity that smoothes the power rectified by rectifier 3, and the voltage generated across smoothing capacitor 5 due to smoothing is not a full-wave rectified waveform of commercial power source 1, but rather a waveform in which a DC component is superimposed with a voltage ripple corresponding to the frequency of commercial power source 1, and does not pulsate significantly. The frequency of this voltage ripple is mainly twice the frequency of the power supply voltage Vs when commercial power source 1 is single-phase, and mainly six times the frequency when commercial power source 1 is three-phase.

[0013] The bus voltage detection unit 10 is a detection unit that detects the voltage across the smoothing capacitor 5, i.e., the voltage between the DC buses 12a and 12b, as the bus voltage Vdc and outputs the detected voltage value to the control device 100. The load current detection unit 40 is a detection unit that detects the load current Idc, which is a DC current flowing from the smoothing capacitor 5 to the inverter 30, and outputs the detected current value to the control device 100.

[0014] The inverter 30 is connected to both ends of 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, i.e., generates the second AC power, and outputs it to the motor 7. Specifically, the inverter 30 receives the bus voltage Vdc and generates a three-phase AC voltage with a variable frequency and voltage value, which is supplied to the motor 7 via output lines 331 to 333. As shown in FIG. 2 , the inverter 30 includes an inverter main circuit 310 and a drive circuit 350. 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 to 316. Return rectifying elements 321 to 326 are connected in anti-parallel to the switching elements 311 to 316, respectively.

[0015] The drive circuit 350 generates drive signals Sr1 to Sr6 based on PWM (Pulse Width Modulation) signals Sm1 to Sm6 output from the control device 100. The drive circuit 350 controls the on / off of the switching elements 311 to 316 using the drive signals Sr1 to Sr6. This enables the inverter 30 to supply a three-phase AC voltage with variable frequency and voltage to the motor 7 via the output lines 331 to 333.

[0016] The PWM signals Sm1 to Sm6 are signals having a signal level of a logic circuit, i.e., a magnitude of 0 V to 5 V. The PWM signals Sm1 to Sm6 are signals with the ground potential of the control device 100 as their reference potential. On the other hand, the drive signals Sr1 to Sr6 are signals having a voltage level required to control the switching elements 311 to 316, for example, a magnitude of -15 V to +15 V. The drive signals Sr1 to Sr6 are signals with the potential of the negative terminal, i.e., the emitter terminal, of the corresponding switching elements 311 to 316 as their reference potential.

[0017] The motor 7 rotates in accordance with the amplitude and phase of the second AC power supplied from the inverter 30. The motor 7 is used, for example, for compressing a compressor or rotating a fan. While the motor 7 shown in FIG. 1 has a Y-connection as its motor windings, this is merely an example and is not limiting. The motor windings of the motor 7 may be a Δ-connection, or may be switchable between a Y-connection and a Δ-connection.

[0018] Note that the arrangement of the components in the power conversion device 200 shown in Fig. 1 is one example, and the arrangement of the components is not limited to the example shown in Fig. 1. For example, the reactor 2 may be arranged after the rectifier 3. Furthermore, the power conversion device 200 may include a booster unit, or the rectifier 3 may be given the function of a booster unit. In the following description, the bus voltage detection unit 10 and the load current detection unit 40 may be collectively referred to as the detection unit. Furthermore, 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 the detection value.

[0019] The control device 100 acquires the bus voltage Vdc from the bus voltage detection unit 10 and the load current Idc from the load current detection unit 40. The control device 100 uses the detection values ​​detected by each detection unit to control the operation of the inverter main circuit 310, specifically, the on / off of the switching elements 311 to 316 included in the inverter main circuit 310. The control device 100 controls the rotation speed of the motor 7 by controlling the on / off of the switching elements 311 to 316 included in the inverter main circuit 310. The control device 100 also calculates the load torque of the motor 7. Note that the control device 100 does not need to use all of the detection values ​​acquired from each detection unit, and may perform control using only some of the detection values. In this embodiment, the control device 100 performs control in a rotating coordinate system having a d-axis and a q-axis.

[0020] The following describes the detailed configuration and operation of the control device 100. Fig. 3 is a block diagram showing an example configuration of the control device 100 provided in the power conversion device 200 according to the first embodiment. The control device 100 includes an operation control unit 102 and an inverter control unit 110.

[0021] The operation control unit 102 acquires command information Qe from an external source. For example, when the power conversion device 200 is installed in an air conditioner that is a refrigeration cycle-applied device, the command information Qe is information based on a temperature detected by a temperature sensor (not shown), information indicating a set temperature instructed from a remote control (not shown) that is an operation unit, information on the selection of an operation mode, and information on instructions to start and stop operation. The operation mode is, for example, heating, cooling, dehumidification, etc. The operation control unit 102 acquires a frequency command value ωe for generating a voltage command value that is a command value for the voltage to be applied to the motor 7 based on the command information Qe. ＊ The operation control unit 102 generates the frequency command value ωe ＊ The rotational angular velocity command value ωm ＊ The operation control unit 102 generates a stop signal St, which is a signal for stopping the operation of the inverter 30, based on the command information Qe. ＊ to the voltage command value calculation unit 115 of the inverter control unit 110 , and outputs a stop signal St to the PWM signal generation unit 118 of the inverter control unit 110 .

[0022] The inverter control unit 110 includes a current restoration unit 111, a three-phase to two-phase conversion unit 112, a d-axis current command value generation unit 113, a voltage command value calculation unit 115, an electrical phase calculation unit 116, a two-phase to three-phase conversion unit 117, and a PWM signal generation unit 118.

[0023] The current restoration unit 111 restores the phase currents iu, iv, and iw flowing through the motor 7 based on the load current Idc detected by the load current detection unit 40. The current restoration unit 111 can restore the phase currents iu, iv, and iw by sampling the load current Idc detected by the load current detection unit 40 at timings determined based on the PWM signals Sm1 to Sm6 generated by the PWM signal generation unit 118.

[0024] The three-phase to two-phase conversion unit 112 converts the phase currents iu, iv, and iw restored by the current restoration unit 111 into a d-axis current id, which is an excitation current, and a q-axis current iq, which is a torque current, i.e., current values ​​of the d and q axes, using the electrical phase θe generated by the electrical phase calculation unit 116 described later.

[0025] The d-axis current command value generating unit 113 generates the d-axis current command value Id ＊ Specifically, the d-axis current command value generator 113 generates a q-axis current iq, a bus voltage Vdc, and a d-axis voltage command value Vd ＊ and the q-axis voltage command value Vq ＊ Based on this, the optimum d-axis current command value Id that will be most efficient for driving the motor 7 is calculated. ＊ The d-axis current command value generator 113 calculates the q-axis current iq, the bus voltage Vdc, and the d-axis voltage command value Vd ＊ , and the q-axis voltage command value Vq ＊ Based on the above, the d-axis current command value Id is set to a current phase βm at which the output torque of the motor 7 is equal to or greater than a specified value or is at its maximum, i.e., the current value is equal to or less than a specified value or is at its minimum. ＊ Here, the d-axis current command value generating unit 113 outputs the d-axis current command value Id based on the q-axis current iq, etc. ＊ However, this is just an example and is not limiting. The d-axis current command value generating unit 113 calculates the d-axis current id, the frequency command value ωe ＊ Based on the above, the d-axis current command value Id ＊ The d-axis current command value generator 113 can obtain the d-axis current command value Id ＊ may be determined.

[0026] The voltage command value calculation unit 115 calculates the frequency command value ωe obtained from the operation control unit 102. ＊ the d-axis current id and the q-axis current iq acquired from the three-phase to two-phase conversion unit 112, and the d-axis current command value Id acquired from the d-axis current command value generation unit 113. ＊ Based on this, the d-axis voltage command value Vd ＊ and the q-axis voltage command value Vq ＊ Furthermore, the voltage command value calculation unit 115 generates the d-axis voltage command value Vd＊ and the q-axis voltage command value Vq ＊ The frequency estimation value ωest is estimated based on the d-axis current id and the q-axis current iq.

[0027] The electrical phase calculation unit 116 calculates the electrical phase θe by integrating the frequency estimate value ωest acquired from the voltage command value calculation unit 115 .

[0028] The two-phase to three-phase conversion unit 117 converts the d-axis voltage command value Vd ＊ and the q-axis voltage command value Vq ＊ , that is, the voltage command value in the two-phase coordinate system is calculated by using the electrical phase θe acquired from the electrical phase calculation unit 116 to calculate the three-phase voltage command value Vu ＊ , Vv ＊ , Vw ＊ Convert to.

[0029] The PWM signal generator 118 converts the three-phase voltage command value Vu acquired from the two-phase to three-phase converter 117 into a three-phase voltage command value Vu ＊ , Vv ＊ , Vw ＊ and the stop signal St obtained from the operation control unit 102. The PWM signal generation unit 118 can also stop the motor 7 by not outputting the PWM signals Sm1 to Sm6 based on the stop signal St.

[0030] The configuration and operation of the voltage command value calculation unit 115 will be described in detail. Fig. 4 is a block diagram showing an example configuration of the voltage command value calculation unit 115 provided in the control device 100 of the power conversion device 200 according to embodiment 1. The voltage command value calculation unit 115 includes a frequency estimation unit 501, addition / subtraction units 502, 504, 505, 509, and 513, a speed control unit 503, a d-axis current control unit 506, a q-axis current control unit 507, multiplication units 508, 510, and 512, and an addition unit 511.

[0031] The frequency estimation unit 501 estimates the d-axis current id, the q-axis current iq, and the d-axis voltage command value Vd ＊ and the q-axis voltage command value Vq ＊The addition / subtraction unit 502 estimates the frequency of the voltage supplied to the motor 7 based on the frequency command value ωe and outputs it as a frequency estimate value ωest. Note that the frequency estimate value ωest output from the frequency estimator 501 to the outside of the voltage command value calculator 115 in FIG. 4 is the frequency estimate value ωest output from the voltage command value calculator 115 to the electrical phase calculator 116 in FIG. ＊ The frequency command value ωe is calculated by subtracting the frequency estimated value ωest from ＊ and the frequency estimated value ωest, and outputs the frequency deviation del_ω.

[0032] The speed control unit 503 calculates the q-axis current command value Iq based on the frequency deviation del_ω. ＊ The q-axis current command value Iq is calculated and output. ＊ is the command value of the q-axis current iq at which the frequency deviation del_ω becomes zero, that is, the frequency command value ωe ＊ is a command value of the q-axis current iq for matching the estimated frequency value ωest with the estimated frequency value ωest. The speed control unit 503 is, for example, a proportional-integral (PI) controller, but is not limited to this.

[0033] The adder / subtractor 504 calculates the d-axis current command value Id ＊ The d-axis current command value Id is obtained by subtracting the d-axis current Id from the ＊ The d-axis current control unit 506 performs PI control and, in parallel, performs reduction control to reduce pulsating components that occur due to the dead time of the switching elements 311 to 316 of the inverter 30 and the influence of induced voltage distortion of the motor 7, and outputs the d-axis current command value Id_err. ＊ The d-axis current control unit 506 operates to converge the deviation between the first d-axis voltage command value Vdfb ＊ The detailed configuration and operation of the d-axis current control unit 506 will be described later.

[0034] The adder / subtractor 505 calculates the q-axis current command value Iq ＊ The q-axis current command value Iq is calculated by subtracting the q-axis current iq from ＊The q-axis current control unit 507 performs PI control and, in parallel, performs reduction control to reduce pulsation components generated due to the dead time of the switching elements 311 to 316 of the inverter 30 and the influence of induced voltage distortion of the motor 7, thereby outputting the q-axis current command value Iq_err. ＊ The q-axis current control unit 507 operates to converge the deviation between the first q-axis voltage command value Vqfb ＊ The detailed configuration and operation of the q-axis current control unit 507 will be described later.

[0035] The multiplication unit 508 calculates the q-axis current command value Iq ＊ is multiplied by the q-axis inductance Lq of the motor 7 and the frequency estimate value ωest to obtain a first d-axis voltage command value Vdfb ＊ Compensation value Vdff ＊ The adder / subtractor 509 calculates and outputs the first d-axis voltage command value Vdfb ＊ to the compensation value Vdff ＊ to obtain the first d-axis voltage command value Vdfb ＊ and compensation value Vdff ＊ Deviation from (Vdfb ＊ -Vdff ＊ ) is converted into the d-axis voltage command value Vd ＊ Output as

[0036] The multiplication unit 510 calculates the d-axis current command value Id ＊ The adder 511 multiplies the output from the multiplier 510 by the d-axis inductance Ld of the motor 7 and outputs the result. The adder 511 adds the magnetic flux linkage vector φf of the motor 7 to the output from the multiplier 510. The multiplier 512 multiplies the output from the adder 511 by the frequency estimate value ωest to obtain a first q-axis voltage command value Vqfb ＊ Compensation value Vqff ＊ The addition / subtraction unit 513 calculates and outputs the first q-axis voltage command value Vqfb ＊ to the compensation value Vqff ＊ to obtain the first q-axis voltage command value Vqfb ＊ and compensation value Vqff ＊ Deviation from (Vqfb ＊ -Vqff ＊) is converted into the q-axis voltage command value Vq ＊ Output as

[0037] Next, the control performed by the control device 100 in the power conversion device 200 to reduce harmonic components contained in the d-axis current id and the q-axis current iq that are six times the power supply frequency of the first AC power supplied from the commercial power supply 1 will be described. In the following description, for simplicity, the harmonic components that are six times the power supply frequency of the first AC power supplied from the commercial power supply 1 will be referred to as electrical 6f components. Specifically, in the voltage command value calculation unit 115 of the control device 100, the d-axis current control unit 506 performs reduction control to reduce the electrical 6f component contained in the d-axis current id, and the q-axis current control unit 507 performs reduction control to reduce the electrical 6f component contained in the q-axis current iq. The detailed configurations and operations of the d-axis current control unit 506 and the q-axis current control unit 507 will be described below.

[0038] 5 is a block diagram showing an example configuration of the d-axis current control unit 506 included in the voltage command value calculation unit 115 of the control device 100 in the power conversion device 200 according to the first embodiment. The d-axis current control unit 506 includes a d-axis current PI control unit 601, multiplication units 602, 603, 610, and 611, low-pass filters 604 and 605, addition and subtraction units 606 and 607, PI control units 608 and 609, and addition units 612 and 613. As shown in FIG. 5 , in the d-axis current control unit 506, the d-axis current PI control unit 601 and the components from the multiplication unit 602 to the addition unit 612 perform control in parallel.

[0039] The d-axis current PI control unit 601 calculates the d-axis current command value Id output from the addition / subtraction unit 504 in a general voltage command value calculation unit 115. ＊ The d-axis current PI control unit 601 controls the current by proportional-plus-integral calculation of the deviation Id_err between the d-axis voltage command value V ＊ Output d_PI.

[0040] The multiplication unit 602 first multiplies the deviation Id_err by cos(ωe6f) to extract the cos component from the electrical 6f component included in the deviation Id_err output from the addition / subtraction unit 504. ωe6f is obtained by multiplying the electrical phase θe calculated by the electrical phase calculation unit 116 by six. The d-axis current control unit 506 may calculate ωe6f internally, or may calculate ωe6f using the electrical phase θe calculated by the electrical phase calculation unit 116. The value calculated by the multiplication unit 602 includes not only a pulsating component with a frequency of ωe6f but also pulsating components with frequencies higher than ωe6f, i.e., harmonic components.

[0041] The multiplication unit 603 first multiplies the deviation Id_err by sin(ωe6f) to extract the sin component from the electrical 6f component contained in the deviation Id_err output from the addition / subtraction unit 504. ωe6f is the same as that used in the multiplication unit 602. The value calculated by the multiplication unit 603 includes not only the pulsating component with a frequency of ωe6f but also pulsating components with frequencies higher than ωe6f, i.e., harmonic components.

[0042] The low-pass filters 604 and 605 are first-order lag filters whose transfer function is expressed as 2 / (1+Tf·s). Here, s is a Laplace operator. Tf is a time constant determined to remove pulsating components at frequencies higher than ωe6f. Note that "removal" includes the attenuation, i.e., reduction, of a portion of the pulsating components. The time constant Tf may be set by the operation control unit 102 based on the speed command and notified to the low-pass filters 604 and 605 by the operation control unit 102, or may be stored in the low-pass filters 604 and 605. The first-order lag filter is an example of the low-pass filters 604 and 605. Moving average filters and other filters may also be used. The type of filter is not limited as long as it can remove high-frequency pulsating components. Note that the amplitude of the low-pass filters 604 and 605 is halved by the filtering process, so the denominator of the transfer function is doubled by "2."

[0043] The low-pass filter 604 performs low-pass filtering on the output from the multiplication unit 602 to remove pulsating components of frequencies higher than ωe6f, and outputs a low-frequency component Ide_6f_cos. The low-frequency component Ide_6f_cos is a direct current amount representing the cosine component with a frequency of ωe6f among the pulsating components of the deviation Id_err.

[0044] The low-pass filter 605 performs low-pass filtering on the output from the multiplication unit 603 to remove pulsating components of frequencies higher than ωe6f, and outputs a low-frequency component Ide_6f_sin. The low-frequency component Ide_6f_sin is a direct current amount representing the sin component with a frequency of ωe6f among the pulsating components of the deviation Id_err.

[0045] The adding / subtracting unit 606 calculates the difference (Ide_6f_cos-0) between the low-frequency component Ide_6f_cos output from the low-pass filter 604 and the command value 0. Here, the command value is set to 0 because it is desired to reduce the low-frequency component Ide_6f_cos, that is, ideally to set it to 0. The control device 100 may set the command value to a value other than 0 as long as the control stability, noise, and the like are at a satisfactory level.

[0046] The adding / subtracting unit 607 calculates the difference (Ide_6f_sin-0) between the low-frequency component Ide_6f_sin output from the low-pass filter 605 and the command value 0. Here, the command value is set to 0 because it is desired to reduce the low-frequency component Ide_6f_sin, that is, ideally to set it to 0. The control device 100 may set the command value to a value other than 0 as long as the control stability, noise, and the like are at a satisfactory level.

[0047] The PI control unit 608 performs proportional integral calculation on the difference (Ide_6f_cos-0) calculated by the addition / subtraction unit 606, and calculates the cos component of the current command value that brings the difference (Ide_6f_cos-0) closer to 0. By generating the cos component of the current command value in this manner, the PI control unit 608 performs control to make the low-frequency component Ide_6f_cos equal to 0.

[0048] The PI control unit 609 performs proportional integral calculation on the difference (Ide_6f_sin-0) calculated by the addition / subtraction unit 607, and calculates the sine component of the current command value that brings the difference (Ide_6f_sin-0) closer to 0. By generating the sine component of the current command value in this way, the PI control unit 609 performs control to make the low frequency component Ide_6f_sin coincide with 0.

[0049] The multiplier 610 multiplies the cosine component of the current command value output from the PI control unit 608 by cos(ωe6f). As described above, the output from the low-pass filter 604 is a DC amount, and therefore the calculations of the adder / subtractor 606 and the PI control unit 608 are targeted at the DC amount. Therefore, the multiplier 610 multiplies the cosine component of the current command value output from the PI control unit 608 by cos(ωe6f) to generate a command value having an AC component of ωe6f.

[0050] Multiplication unit 611 multiplies the sine component of the current command value output from PI control unit 609 by sin(ωe6f). As described above, the output from low-pass filter 605 is a DC amount, and therefore the calculations of addition / subtraction unit 607 and PI control unit 609 are targeted at DC amounts. Therefore, multiplication unit 611 multiplies the sine component of the current command value output from PI control unit 609 by sin(ωe6f) to generate a command value having an AC component of ωe6f.

[0051] The adder 612 adds the command value having an AC component of ωe6f calculated by the multiplier 610 and the command value having an AC component of ωe6f calculated by the multiplier 611 to obtain the d-axis voltage command value V calculated by the d-axis current PI control unit 601. ＊ AC compensation value V for compensating for d_PI ＊ d_ωe_6f is generated and output.

[0052] The adder 613 calculates the d-axis voltage command value V ＊ d_PI and the compensation value V calculated by the adder 612 ＊ d_ωe_6f to obtain the first d-axis voltage command value Vdfb ＊ Generate and output.

[0053] 6 is a block diagram showing an example configuration of the q-axis current control unit 507 included in the voltage command value calculation unit 115 of the control device 100 in the power conversion device 200 according to embodiment 1. The q-axis current control unit 507 includes a q-axis current PI control unit 621, multiplication units 622, 623, 630, and 631, low-pass filters 624 and 625, addition and subtraction units 626 and 627, PI control units 628 and 629, and addition units 632 and 633. As shown in FIG. 6 , in the q-axis current control unit 507, the q-axis current PI control unit 621 and the components from the multiplication unit 622 to the addition unit 632 perform control in parallel.

[0054] The q-axis current PI control unit 621 calculates the q-axis current command value Iq output from the addition / subtraction unit 505 in a general voltage command value calculation unit 115. ＊ The q-axis current PI control unit 621 controls the current by proportional-plus-integral calculation of the deviation Iq_err between the q-axis voltage command value V ＊ Output q_PI.

[0055] The multiplication unit 622 first multiplies the deviation Iq_err by cos(ωe6f) to extract the cos component from the electrical 6f component included in the deviation Iq_err output from the addition / subtraction unit 505. ωe6f is obtained by multiplying the electrical phase θe calculated by the electrical phase calculation unit 116 by six. The q-axis current control unit 507 may calculate ωe6f internally, or may calculate ωe6f using the electrical phase θe calculated by the electrical phase calculation unit 116. The value calculated by the multiplication unit 622 includes not only a pulsating component with a frequency of ωe6f but also pulsating components with frequencies higher than ωe6f, i.e., harmonic components.

[0056] The multiplication unit 623 first multiplies the deviation Iq_err by sin(ωe6f) to extract the sin component from the electrical 6f component contained in the deviation Iq_err output from the addition / subtraction unit 505. ωe6f is the same as that used in the multiplication unit 622. The value calculated by the multiplication unit 623 includes not only the pulsating component with a frequency of ωe6f but also pulsating components with frequencies higher than ωe6f, i.e., harmonic components.

[0057] The low-pass filters 624 and 625 are first-order lag filters whose transfer function is expressed as 2 / (1+Tf·s). Here, s is a Laplace operator. Tf is a time constant determined to remove pulsating components at frequencies higher than ωe6f. Note that "removal" includes the case where a portion of the pulsating components is attenuated, i.e., reduced. The time constant Tf is set by the operation control unit 102 based on the speed command and may be notified to the low-pass filters 624 and 625 by the operation control unit 102, or may be stored by the low-pass filters 624 and 625. The first-order lag filter is just an example of the low-pass filters 624 and 625. Moving average filters and other filters may also be used, and the type of filter is not limited as long as it can remove high-frequency pulsating components. Note that the amplitude of the low-pass filters 624 and 625 is halved during filtering, so the denominator of the transfer function is doubled by "2."

[0058] The low-pass filter 624 performs low-pass filtering on the output from the multiplication unit 622 to remove pulsating components of frequencies higher than ωe6f, and outputs a low-frequency component Iqe_6f_cos. The low-frequency component Iqe_6f_cos is a direct current quantity representing the cosine component with a frequency of ωe6f among the pulsating components of the deviation Iq_err.

[0059] The low-pass filter 625 performs low-pass filtering on the output from the multiplication unit 623 to remove pulsating components of frequencies higher than ωe6f, and outputs a low-frequency component Iqe_6f_sin. The low-frequency component Iqe_6f_sin is a direct current amount representing the sin component with a frequency of ωe6f among the pulsating components of the deviation Iq_err.

[0060] The adding / subtracting unit 626 calculates the difference (Iqe_6f_cos-0) between the low-frequency component Iqe_6f_cos output from the low-pass filter 624 and the command value 0. Here, the command value is set to 0 because it is desired to reduce the low-frequency component Iqe_6f_cos, that is, ideally to set it to 0. The control device 100 may set the command value to a value other than 0 as long as the control stability, noise, and the like are at a satisfactory level.

[0061] Addition / subtraction unit 627 calculates the difference (Iqe_6f_sin-0) between the low-frequency component Iqe_6f_sin output from low-pass filter 625 and a command value of 0. Here, the command value is set to 0 because it is desired to reduce the low-frequency component Iqe_6f_sin, that is, ideally to set it to 0. Control device 100 may set the command value to a value other than 0 as long as control stability, noise, and the like are at a satisfactory level.

[0062] The PI control unit 628 performs proportional integral calculation on the difference (Iqe_6f_cos-0) calculated by the addition / subtraction unit 626, and calculates the cos component of the current command value that brings the difference (Iqe_6f_cos-0) closer to 0. By generating the cos component of the current command value in this way, the PI control unit 628 performs control to make the low frequency component Iqe_6f_cos equal to 0.

[0063] The PI control unit 629 performs proportional integral calculation on the difference (Iqe_6f_sin-0) calculated by the addition / subtraction unit 627, and calculates the sine component of the current command value that brings the difference (Iqe_6f_sin-0) closer to 0. By generating the sine component of the current command value in this way, the PI control unit 629 performs control to make the low frequency component Iqe_6f_sin coincide with 0.

[0064] The multiplier 630 multiplies the cosine component of the current command value output from the PI control unit 628 by cos(ωe6f). As described above, the output from the low-pass filter 624 is a DC amount, and therefore the calculations of the adder / subtractor 626 and the PI control unit 628 are targeted at the DC amount. Therefore, the multiplier 630 multiplies the cosine component of the current command value output from the PI control unit 628 by cos(ωe6f) to generate a command value having an AC component of ωe6f.

[0065] Multiplication unit 631 multiplies the sine component of the current command value output from PI control unit 629 by sin(ωe6f). As described above, the output from low-pass filter 625 is a DC amount, and therefore the calculations of addition / subtraction unit 627 and PI control unit 629 are targeted at DC amounts. Therefore, multiplication unit 631 multiplies the sine component of the current command value output from PI control unit 629 by sin(ωe6f) to generate a command value having an AC component of ωe6f.

[0066] The adder 632 adds the command value having an AC component of ωe6f calculated by the multiplier 630 and the command value having an AC component of ωe6f calculated by the multiplier 631 to obtain the q-axis voltage command value V calculated by the q-axis current PI control unit 621. ＊ AC compensation value V for compensating for q_PI ＊ q_ωe_6f is generated and output.

[0067] The adder 633 calculates the q-axis voltage command value V ＊ q_PI and the compensation value V calculated by the adder 632 ＊ q_ωe_6f to obtain the first q-axis voltage command value Vqfb ＊ Generate and output.

[0068] In this way, the control device 100 performs reduction control to reduce pulsating components superimposed on the three-phase current output from the inverter 30 to the motor 7, which are generated due to the dead time of the switching elements 311 to 316 provided in the inverter 30 and the influence of induced voltage distortion of the motor 7. The three-phase currents are the phase currents iu, iv, and iw restored by the current restoration unit 111. Specifically, the control device 100 converts the three-phase currents into a d-axis current id and a q-axis current iq expressed in a dq rotating coordinate system, extracts pulsating components having a frequency six times the power supply frequency of the commercial power source 1, which are included in the d-axis current id and the q-axis current iq, in parallel with the current control, performs control to reduce the extracted pulsating components, generates a voltage command value, and controls the operation of the switching elements 311 to 316 of the inverter 30. In practice, in the voltage command value calculation unit 115 of the control device 100, the d-axis current control unit 506 performs reduction control to reduce the electrical 6f component contained in the d-axis current id, and the q-axis current control unit 507 performs reduction control to reduce the electrical 6f component contained in the q-axis current iq. This enables the control device 100 to reduce the pulsating component of the electrical 6f component that occurs due to the dead time of the switching elements 311 to 316 provided in the inverter 30 and the influence of the induced voltage distortion of the motor 7.

[0069] The electrical 6f component is a pulsating component obtained when the three-phase current flowing from the inverter 30 of the power conversion device 200 to the motor 7 is converted into a d-axis current id and a q-axis current iq in a dq coordinate system having a d-axis and a q-axis. The pulsating component of the electrical 6f component superimposed on the d-axis current id and the q-axis current iq is expressed as a pulsating component of the electrical 5f component or a pulsating component of the electrical 7f component in the state of the three-phase current flowing from the inverter 30 of the power conversion device 200 to the motor 7. In FIG. 3 , the different ways of expressing the pulsating component before and after the control of the three-phase to two-phase conversion unit 112 and before and after the control of the two-phase to three-phase conversion unit 117 are indicated by "6f" and "5f, 7f." In this way, the control device 100 can be said to control the three-phase current to reduce pulsating components with frequencies five and seven times the power supply frequency of the commercial power supply 1, and can also be said to control the three-phase current to reduce pulsating components with frequencies six times the power supply frequency of the commercial power supply 1, which are generated in the d-axis current id and q-axis current iq expressed in a dq rotating coordinate system converted from the three-phase current.

[0070] The effects obtained by the reduction control of the control device 100 according to this embodiment will be described. FIG. 7 is a diagram showing, as a comparative example, an example of the operating state of the power conversion device 200 when the control device 100 of the power conversion device 200 according to the first embodiment does not perform reduction control to reduce pulsation of the electric 6f component contained in the current. FIG. 8 is a diagram showing an example of the operating state of the power conversion device 200 when the control device 100 of the power conversion device 200 according to the first embodiment performs reduction control to reduce pulsation of the electric 6f component contained in the q-axis current iq. FIG. 9 is a diagram showing an example of the operating state of the power conversion device 200 when the control device 100 of the power conversion device 200 according to the first embodiment performs reduction control to reduce pulsation of the electric 6f component contained in the d-axis current id and the q-axis current iq. In FIGS. 7 to 9 , the first graph from the top shows the actual rotation speed of the motor 7 (solid line), the estimated rotation speed of the motor 7 (dashed line), and the rotation speed command value for the motor 7 (chain line). The second graph from the top shows the load torque of the motor 7 with a solid line and the output torque of the inverter 30 with respect to the motor 7 with a dashed line. The third graph from the top shows the d-axis current id with a solid line and the d-axis current command value id with a dashed line. ＊The fourth graph from the top shows the q-axis current command value iq ＊ The dashed line represents the q-axis current iq. The fifth graph from the top represents the three-phase current. The sixth graph from the top represents the three-phase induced voltage, where distortion due to the pulsating component of the electrical 5f is greatest. In all graphs, the horizontal axis represents time.

[0071] A comparison of Figures 7 and 8 reveals that the control device 100 performs control to reduce the pulsating component of the electricity 6f by targeting the q-axis current iq, thereby significantly improving the output torque of the inverter 30 for the motor 7 and the q-axis current iq, i.e., significantly reducing the pulsating component. It also reveals that the pulsating components are reduced for the d-axis current id and the three-phase current. Because the output torque of the inverter 30 is dominated by the q-axis current iq and the q-axis voltage, the control device 100 can achieve the above-described effects even when it targets only the q-axis current iq. Furthermore, a comparison of Figures 8 and 9 reveals that the control device 100 also performs control to reduce the pulsating component of the electricity 6f by targeting the d-axis current iq, thereby significantly improving the d-axis current id and the three-phase current, i.e., significantly reducing the pulsating component. 7 to 9 do not describe the case where the control device 100 performs control to reduce the pulsation component of the electricity 6f by targeting the d-axis current id, but the control device 100 can also perform control to reduce the pulsation component of the electricity 6f by targeting only the d-axis current id, without targeting the q-axis current iq. For example, in a case where noise that does not contribute to torque is generated in the power conversion device 200 or the motor 7 due to pulsation in the d-axis current id, the control device 100 may be able to improve the noise by performing control to reduce the pulsation component of the electricity 6f by targeting only the d-axis current id.

[0072] The operation of the control device 100 of the power conversion device 200, which is a feature of the first embodiment, will be described using a flowchart. Fig. 10 is a flowchart showing the operation of the power conversion device 200 according to the first embodiment. In the power conversion device 200, the control device 100 controls the d-axis current command value Id ＊The control device 100 performs current control for the deviation Id_err between the d-axis current command value Id and the d-axis current command value Id (step S1). ＊ The control device 100 extracts the pulsating component of the electrical 6f component for the d-axis current id from the deviation Id_err between the d-axis current id and the cosine component as described above, and extracts the pulsating component of the electrical 6f component from the deviation Id_err. The control device 100 then calculates a compensation value V that reduces the extracted pulsating component of the electrical 6f component to zero. ＊ The control device 100 generates the d-axis current command value Id ＊ The d-axis voltage command value V is a value obtained by performing current control on the deviation Id_err between the d-axis current id and ＊ d_PI is the compensation value V ＊ By compensating with d_ωe_6f (step S4), the first d-axis voltage command value Vdfb ＊ Then, the control device 100 generates and outputs the first d-axis voltage command value Vdfb ＊ and the compensation value Vdff calculated using the q-axis inductance Lq of the motor 7, etc. ＊ By compensating with ＊ Generate.

[0073] Similarly, the control device 100 determines the q-axis current command value Iq ＊ and the q-axis current iq, and performs current control for the deviation Iq_err between the q-axis current command value Iq ＊ The control device 100 extracts the pulsating component of the electrical 6f component for the q-axis current iq from the deviation Iq_err between the q-axis current iq and the cosine component as described above, and extracts the pulsating component of the electrical 6f component from the deviation Iq_err (step S6). The control device 100 actually separates the deviation Iq_err into a cosine component and a sinus component as described above, and extracts the pulsating component of the electrical 6f component from the deviation Iq_err. The control device 100 then calculates a compensation value V that makes the extracted pulsating component of the electrical 6f component zero. ＊ The control device 100 generates the q-axis current command value Iq ＊ and the q-axis current iq, and the q-axis voltage command value V ＊ q_PI is the compensation value V ＊By compensating with q_ωe_6f (step S8), the first q-axis voltage command value Vqfb ＊ Then, the control device 100 generates and outputs the first q-axis voltage command value Vqfb ＊ and the compensation value Vqff calculated using the d-axis inductance Ld of the motor 7, etc. ＊ By compensating with ＊ Generate.

[0074] The control device 100 may perform the operations from step S1 to step S4 and the operations from step S5 to step S8 in parallel, or may perform the operations from step S5 to step S8 first.

[0075] Next, a description will be given of the hardware configuration of the control device 100 included in the power conversion device 200. Fig. 11 is a diagram showing an example of a hardware configuration realizing the control device 100 included in the power conversion device 200 according to the first embodiment. The control device 100 is realized by a processor 91 and a memory 92.

[0076] The processor 91 is a CPU (Central Processing Unit, also called a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)) or a system LSI (Large Scale Integration). Examples of memory 92 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Memory 92 is not limited to these, and may also be a magnetic disk, optical disk, compact disk, minidisc, or DVD (Digital Versatile Disc).

[0077] As described above, according to this embodiment, in the power conversion device 200, the control device 100 performs reduction control in the d-axis current control unit 506 to reduce the pulsating component of the electrical 6f component superimposed on the d-axis current i d , and performs reduction control in the q-axis current control unit 507 to reduce the pulsating component of the electrical 6f component superimposed on the q-axis current i q . This allows the control device 100 to reduce the pulsating component generated due to the dead time of the switching elements 311 to 316 included in the inverter 30 and the induced voltage distortion of the motor 7. Even when the inverter 30 is replaced or the motor 7 connected to the power conversion device 200 is replaced, the control device 100 can reduce the pulsating component generated due to the dead time of the switching elements 311 to 316 included in the inverter 30 and the induced voltage distortion of the motor 7 by performing the reduction control described above. As a result, the control device 100 can suppress a decrease in control stability and suppress noise generation.

[0078] Embodiment 2. In the first embodiment, a case was described in which the control device 100 of the power conversion device 200 performs reduction control to reduce pulsation of the electrical 6f component that occurs due to the dead time of the switching elements 311 to 316 of the inverter 30 and the induced voltage distortion of the motor 7. Here, if the pulsation of the electrical 6f component is very small, it is possible that control interference will occur in the control device 100 between the reduction control and the general control that controls the operation of the inverter 30 and the motor 7 when the control device 100 of the power conversion device 200 performs the reduction control described above. When control interference occurs, the control device 100 may not be able to converge at the desired control response speed or may even diverge. In the second embodiment, a case in which the occurrence of control interference in the control device 100 of the power conversion device 200 is reduced will be described.

[0079] In the second embodiment, the configuration of the power conversion device 200 is similar to the configuration of the power conversion device 200 of the first embodiment shown in Fig. 1. Furthermore, the configuration of the control device 100 is similar to the configuration of the control device 100 of the first embodiment shown in Fig. 3. In the second embodiment, the configuration of the voltage command value calculation unit 115 in the control device 100 is different from the configuration of the voltage command value calculation unit 115 of the first embodiment shown in Fig. 4.

[0080] Fig. 12 is a block diagram showing an example of the configuration of the voltage command value calculation unit 115 included in the control device 100 of the power conversion device 200 according to embodiment 2. The voltage command value calculation unit 115 according to embodiment 2 is obtained by adding a band elimination filter 521 to the voltage command value calculation unit 115 according to embodiment 1 shown in Fig. 4 .

[0081] The band elimination filter 521 receives the frequency command value ωe calculated by the addition / subtraction unit 502. ＊ The control device 100 performs a filter process to remove pulsation of the electrical 6f component from the frequency deviation del_ω between the frequency command value ωe calculated by the addition / subtraction unit 502 and the frequency estimated value ωest. ＊ Since the speed control unit 503 does not perform speed control in response to pulsation of the electrical 6f component included in the frequency deviation del_ω between the frequency estimated value ω and the frequency deviation del_ω, it is possible to reduce the occurrence of control interference between the reduction control described in the first embodiment and the speed control of the speed control unit 503. In this way, the control device 100 includes the band elimination filter 521 for reducing interference between the reduction control and the speed control when generating a voltage command value for the q axis.

[0082] Furthermore, the voltage command value calculation unit 115 may include a band elimination filter inside the d-axis current control unit 506 and the q-axis current control unit 507 .

[0083] 13 is a block diagram showing an example of the configuration of the d-axis current control unit 506 provided in the voltage command value calculation unit 115 of the control device 100 in the power conversion device 200 according to the second embodiment. The d-axis current control unit 506 of the second embodiment is obtained by adding a band elimination filter 614 to the d-axis current control unit 506 of the first embodiment shown in FIG.

[0084] The band elimination filter 614 is configured to filter the d-axis current command value Id calculated by the adder / subtractor 504. ＊ The d-axis current PI control unit 601 performs a filtering process to remove pulsation of the electrical 6f component from the deviation Id_err between the d-axis current id and the d-axis current id. ＊ Since current control processing is not performed on the pulsation of the electrical 6f component included in the deviation Id_err between the d-axis current id and the d-axis current id, the d-axis voltage command value V ＊ The d_PI does not include pulsation of the electrical 6f component. As a result, the d-axis current control unit 506 can reduce the occurrence of control interference between the reduction control and current control described in the first embodiment. In this way, the control device 100 includes a band-elimination filter 614 for reducing interference between the reduction control and current control when generating a voltage command value for the d-axis.

[0085] 14 is a block diagram showing an example of the configuration of the q-axis current control unit 507 included in the voltage command value calculation unit 115 of the control device 100 in the power conversion device 200 according to embodiment 2. The q-axis current control unit 507 of embodiment 2 is obtained by adding a band elimination filter 634 to the q-axis current control unit 507 of embodiment 1 shown in FIG.

[0086] The band elimination filter 634 receives the q-axis current command value Iq calculated by the addition / subtraction unit 505. ＊ The q-axis current PI control unit 621 performs a filtering process to remove pulsation of the electrical 6f component from the deviation Iq_err between the q-axis current iq and the q-axis current iq. ＊ Since no current control processing is performed on the pulsation of the electrical 6f component included in the deviation Iq_err between the q-axis current iq and the q-axis current iq, the q-axis voltage command value V ＊ The q_PI does not include pulsation of the electrical 6f component. As a result, the q-axis current control unit 507 can reduce the occurrence of control interference between the reduction control and current control described in the first embodiment. In this way, the control device 100 includes the band elimination filter 634 for reducing interference between the reduction control and the current control when generating a voltage command value for the q axis.

[0087] In the second embodiment, the control device 100 of the power conversion device 200 may be configured to include all three of the band elimination filter 521 described in FIG. 12, the band elimination filter 614 described in FIG. 13, and the band elimination filter 634 described in FIG. 14, or may be configured to include only one or two of them.

[0088] Furthermore, the control device 100 controls the control response of the reduction control so that the control response speed of the current control is at least a specified multiple of the control response speed of the reduction control, thereby reducing the occurrence of control interference between the reduction control and the current control described in embodiment 1. In the control device 100, the d-axis current control unit 506, for example, sets the control response speed of the d-axis current PI control unit 601 that performs current control to at least five times the control response speed from the multiplier unit 602 that performs reduction control to the adder unit 612. The d-axis current control unit 506 can reduce the occurrence of control interference by separating the control response speed of the d-axis current PI control unit 601 that performs current control from the control response speed from the multiplier unit 602 that performs reduction control to the adder unit 612. Similarly, in the control device 100, the q-axis current control unit 507, for example, sets the control response speed of the q-axis current PI control unit 621 that performs current control to at least five times the control response speed from the multiplier unit 622 that performs reduction control to the adder unit 632. The q-axis current control unit 507 can reduce the occurrence of control interference by separating the speed of the control response of the q-axis current PI control unit 621 that performs current control from the speed of the control response from the multiplication unit 622 that performs reduction control to the addition unit 632.

[0089] As described above, according to the present embodiment, in power conversion device 200, control device 100 is provided with a band-elimination filter in at least one of the input stage of speed control unit 503, the input stage of d-axis current PI control unit 601, and the input stage of q-axis current PI control unit 621, which are provided in voltage command value calculation unit 115. This enables control device 100 to reduce the occurrence of control interference between general control that controls the operation of inverter 30 and motor 7 and reduction control that reduces pulsating components that occur due to the influence of dead time of switching elements 311 to 316 provided in inverter 30 and induced voltage distortion of motor 7, as described in the first embodiment.

[0090] Third Embodiment Fig. 15 is a diagram showing a configuration example of a refrigeration cycle-applied device 900 according to a third embodiment. The refrigeration cycle-applied device 900 according to the third embodiment includes the power conversion device 200 described in the first or second embodiment. The refrigeration cycle-applied device 900 according to the third embodiment can be applied to products equipped with a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters. In Fig. 15, components having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0091] The refrigeration cycle application equipment 900 includes a compressor 8 incorporating the motor 7 in embodiment 1, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910, which are attached via refrigerant piping 912.

[0092] Inside the compressor 8, a compression mechanism 904 that compresses the refrigerant and a motor 7 that operates the compression mechanism 904 are provided.

[0093] The refrigeration cycle device 900 can perform heating or cooling operation by switching the four-way valve 902. The compression mechanism 904 is driven by a motor 7 that is variably controlled in speed.

[0094] During heating operation, as shown by the solid arrow, the refrigerant is pressurized by the compression mechanism 904 and sent out, passes 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 and returns to the compression mechanism 904.

[0095] During cooling operation, as shown by the dashed arrow, the refrigerant is pressurized by the compression mechanism 904 and sent out, passes 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 and returns to the compression mechanism 904.

[0096] 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.

[0097] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention.

[0098] 1 Commercial power supply, 2 Reactor, 3 Rectification unit, 5 Smoothing capacitor, 7 Motor, 8 Compressor, 10 Bus voltage detection unit, 12a, 12b DC bus, 30 Inverter, 40 Load current detection unit, 91 Processor, 92 Memory, 100 Control device, 102 Operation control unit, 110 Inverter control unit, 111 Current restoration unit, 112 3-phase 2-phase conversion unit, 113 d-axis current command value generation unit, 115 Voltage command value calculation unit, 116 Electrical phase calculation unit, 117 2-phase 3-phase conversion unit, 118 PWM signal generation unit, 131 to 134, 321 to 326 Rectification element, 200 Power conversion device, 310 Inverter main circuit, 311 to 316 Switching elements, 331 to 333 Output line, 350 Drive circuit, 400 Motor drive device, 501 Frequency estimation unit, 502, 504, 505, 509, 513, 606, 607, 626, 627 Addition / subtraction unit, 503 Speed ​​control unit, 506 d-axis current control unit, 507 q-axis current control unit, 508, 510, 512, 602, 603, 610, 611, 622, 623, 630, 631 Multiplication unit, 511, 612, 613, 632, 633 Addition unit, 521, 614, 634 Band elimination filter, 601 d-axis current PI control unit, 604, 605, 624, 625 Low-pass filter, 608, 609, 628, 629 PI control unit, 621 q-axis current PI control unit, 900 Refrigeration cycle applied equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 expansion valve, 910 outdoor heat exchanger, 912 refrigerant piping.

Claims

1. a rectification unit that rectifies a first AC power supplied from a commercial power source; A capacitor connected to an output terminal of the rectifier unit; an inverter connected across the capacitor to generate a second AC power and output the second AC power to a motor; a control device that controls an operation of the inverter to control a rotation speed of the motor, and that performs reduction control to reduce a pulsating component that is generated due to the influence of a dead time of a switching element of the inverter and an induced voltage distortion of the motor and that is superimposed on a three-phase current output from the inverter to the motor; Equipped with The control device includes: a conversion unit for converting the three-phase currents into a d-axis current and a q-axis current expressed in a dq rotating coordinate system; a first current control unit that performs current control for a first deviation between a d-axis current command value and the d-axis current; a first compensation value generating unit that generates a first compensation value that reduces the pulsation component included in the first deviation; a second current control unit that performs current control for a second deviation between a q-axis current command value and the q-axis current; a second compensation value generating unit that generates a second compensation value that reduces the pulsation component included in the second deviation; Equipped with compensating an output from the first current control section with the first compensation value, and compensating an output from the second current control section with the second compensation value; Power conversion equipment.

2. The control device performs control so as to reduce pulsation components generated in the three-phase current and having frequencies five and seven times an electrical angular frequency based on the rotation of the motor. The power conversion device according to claim 1 .

3. the control device controls so as to reduce a pulsation component having a frequency six times an electrical angular frequency based on the rotation of the motor, the pulsation component being generated in a d-axis current and a q-axis current expressed in a dq rotating coordinate system obtained by converting the three-phase current. The power conversion device according to claim 1 .

4. The control device extracts, in parallel with the current control, pulsation components having a frequency six times the electrical angular frequency based on the rotation of the motor, which are included in the d-axis current and the q-axis current, and performs control to reduce the extracted pulsation components to generate a voltage command value and control the operation of the switching element. The power conversion device according to claim 1 .

5. The control device includes a band elimination filter for reducing interference between the reduction control and a speed control when generating the voltage command value for the q axis. The power conversion device according to claim 4.

6. the control device includes a band elimination filter for reducing interference between the reduction control and a current control when generating the voltage command value for the d axis, and a band elimination filter for reducing interference between the reduction control and a current control when generating the voltage command value for the q axis. The power conversion device according to claim 4.

7. The control device controls a control response of the reduction control so that a control response speed of the current control is equal to or greater than a specified multiple of a control response speed of the reduction control. The power conversion device according to claim 4.

8. A motor drive device comprising the power conversion device according to any one of claims 1 to 7.

9. A refrigeration cycle device comprising the power conversion device according to any one of claims 1 to 7.