Drive device, compressor drive system, and refrigeration cycle device

Abstract

A drive device (4) that drives an AC motor (1) by means of an inverter (11) includes a current detection unit (12) that detects the current flowing through the AC motor, a rotor position calculation unit (14) that calculates rotor position information which is information on the position of the rotor of the AC motor, a voltage command determination unit (15) that determines a voltage command based on the current vector of the current and the rotor position information, and a beatless control unit (18) that suppresses the pulsation of the current caused by the periodic pulsation of the DC bus voltage by operating the voltage phase of the voltage command. The beatless control unit has a norm calculation unit that calculates the norm of the current vector, a pulsation extraction unit that extracts the pulsating component of the norm, and an automatic search unit that searches for the operation amount of the voltage phase at which the pulsating component is minimized. The beatless control unit operates the voltage phase using the operation amount.

Description

Technical Field

[0001] The present disclosure relates to a driving device that drives a driven object using alternating current power, a compressor drive system, and a refrigeration cycle device.

Background Art

[0002] A driving device that combines an AC (Alternating Current) - DC (Direct Current) converter and a DC - AC converter (inverter) is frequently used to drive an alternating current motor. A capacitor is used in the DC bus section of this driving device. Also, a reactor is often inserted on the AC - DC converter side for the purpose of power factor improvement and boosting. For this driving device, miniaturization and downsizing of the capacitor and the reactor have been studied for the purpose of cost reduction.

[0003] However, when a capacitor or reactor with a small capacitance is used, the periodic pulsation of the DC bus voltage increases, which has an adverse effect on the current control of the alternating current motor. In particular, when the pulsation frequency (disturbance frequency) of the DC bus voltage and the frequency of the phase current of the alternating current motor are close to each other, a low - frequency current pulsation called beat vibration occurs. When the phase current pulsates due to beat vibration, demerits such as deterioration of the motor efficiency due to an increase in the current peak value, a decrease in the maximum output of the motor due to the constraints of over - current protection, and an increase in the vibration or noise of the alternating current motor occur.

[0004] Various methods for beatless control, which is control for suppressing beat vibration, have been proposed so far. For example, a driving device that performs beatless control detects at least one of the DC bus voltage and the motor current, extracts the pulsation component included in the detected DC bus voltage or motor current by a band - pass filter or the like, and performs feedback control so that the extracted pulsation component is reduced, thereby suppressing beat vibration.

[0005] The beatless control of Patent Document 1 extracts the cosine component and sine component included in the pulsation of the q-axis current based on the principle of Fourier series, proportionally controls or integrates these components respectively, and then restores the control result to an AC signal to correct the dq-axis voltage output to the inverter.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the technology of the above Patent Document 1, in the voltage saturation region of the inverter voltage, a desired voltage operation cannot be performed, so there is a problem that the pulsation cannot be reduced as intended.

[0008] The present disclosure has been made in view of the above, and an object thereof is to obtain a drive device capable of reducing pulsation as intended even in the voltage saturation region of the inverter voltage.

Means for Solving the Problems

[0009] In order to solve the above-described problems and achieve the object, the drive device of the present disclosure is a drive device that drives an AC motor by an inverter, and includes a current detection unit that detects a current flowing through the AC motor, and a rotor position calculation unit that calculates rotor position information that is information on the position of the rotor included in the AC motor. Further, the drive device of the present disclosure includes a voltage command determination unit that determines a voltage command based on the current vector of the current and the rotor position information, and a beatless control unit that suppresses the pulsation of the current caused by the periodic pulsation of the DC bus voltage by operating the voltage phase of the voltage command. The beatless control unit includes a norm calculation unit that calculates the norm of the current vector, and the pulsation component of the norm Separated into a cosine component and a sine componentIt includes a pulsation extraction unit that extracts pulsations, and an automatic search unit that searches for an operation amount of the voltage phase in which the pulsation component is minimized. The beatless control unit operates the voltage phase using the operation amount. The automatic search unit searches for an operation amount that minimizes the cosine component and the sine component, and includes a rotation operation unit that performs a rotation operation on the cosine component and the sine component, a first integration control unit that integrates the rotated cosine component, a second integration control unit that integrates the rotated sine component, and an AC restoration unit that calculates the operation amount based on the integrated cosine component, the integrated sine component, and the disturbance frequency that is the pulsation frequency of the DC bus voltage.

Advantages of the Invention

[0010] The drive device according to the present disclosure has the effect that pulsations can be reduced as intended even in the voltage saturation region of the inverter voltage.

Brief Description of the Drawings

[0011]

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Mode for Carrying Out the Invention

[0012] Hereinafter, a drive device, a compressor drive system, and a refrigeration cycle device according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] Embodiment 1. FIG. 1 is a diagram showing the configuration of a drive device according to Embodiment 1. The drive device 4 is a device that converts AC power into desired power to drive an AC motor 1. The rotating shaft of the AC motor 1 is mechanically connected to a mechanical device 2. The mechanical device 2 is, for example, a refrigerant compression mechanism. The compressor 3 is constituted by the AC motor 1 and the mechanical device 2. A system including the drive device 4 and the compressor 3 is a compressor drive system 800 described later.

[0014] Note that the compression mechanism is merely an example of the mechanical device 2 driven by the AC motor 1, and the driving device 4 can also be applied to other types of mechanical devices. The driving device 4 converts the AC power input from the AC power supply 5 and drives the AC motor 1. There is a power supply impedance (parasitic impedance) between the driving device 4 and the AC power supply 5. The power supply inductance 6 is the inductance component of the power supply impedance.

[0015] For convenience of explanation, here, the case where the AC power supply 5 as the input power supply is a three-phase AC will be described. However, the driving device 4 of the first embodiment is also applicable when the AC power supply 5 is a single-phase AC.

[0016] The driving device 4 includes a diode rectifier 7, a DC reactor 8, a capacitor 9, a DC bus voltage detection unit 10, an inverter 11, a current detection unit 12, and a control unit 400.

[0017] In the driving device 4, an AC-DC converter is constituted by the diode rectifier 7, the DC reactor 8, the capacitor 9, etc. The driving device 4 converts the input AC voltage into a DC voltage by this AC-DC converter. The AC-DC converter shown in FIG. 1 is a very simple AC-DC converter, but when power factor improvement or boosting is required, another type of AC-DC converter may be used.

[0018] One end of the DC reactor 8 is connected to the output point on the positive electrode side of the diode rectifier 7, and the other end of the DC reactor 8 is connected to the input point on the positive electrode side of the inverter 11. Also, one end of the capacitor 9 is connected to the other end of the DC reactor 8. The other end of the capacitor 9 is connected to the output point on the negative electrode side of the diode rectifier 7 and the input point on the negative electrode side of the inverter 11. The DC reactor 8 and the capacitor 9 are provided to smooth the DC power output from the diode rectifier 7.

[0019] The DC bus voltage detection unit 10 detects the voltage across the capacitor 9 as the DC bus voltage V DCIt is detected as and output to the control unit 400. The inverter 11 converts a DC voltage into an AC voltage and drives the AC motor 1 with the AC voltage.

[0020] The current detection unit 12 detects the phase current (phase current vector I uvw ) flowing from the inverter 11 to the AC motor 1 and outputs it to the control unit 400. The control unit 400 performs a series of control operations for driving the AC motor 1. The detailed hardware configuration of the control unit 400 will be described later.

[0021] The control unit 400 includes a modulation unit 13, a rotor position calculation unit 14, a voltage command determination unit 15, a coordinate conversion unit 16, a coordinate conversion unit 17, a vectorless control unit 18, and an adder 19. The coordinate conversion unit 17 is the first coordinate conversion unit, and the coordinate conversion unit 16 is the second coordinate conversion unit.

[0022] The control unit 400 controls the AC motor 1 in the rotating two-phase coordinate system. Here, the case where the control unit 400 performs control in the dq rotating coordinate system based on the direction of the rotor magnet will be described, but the control unit 400 may perform control in a coordinate system other than the dq rotating coordinate system.

[0023] In order to perform control in the rotating two-phase coordinate system, the control unit 400 obtains the angular difference between the fixed two-phase coordinate and the rotating two-phase coordinate. The drive device 4 of the first embodiment estimates the estimated magnetic pole position θ^ * dq and the estimated angular velocity ω^ dq from the dq-axis voltage command vector V e and the dq-axis current vector I e . Hereinafter, the information indicated by " * " is command information, and the information indicated by "^" is estimated information.

[0024] The dq-axis voltage command vector V * dq corresponds to the voltage applied by the inverter 11 to the AC motor 1. The dq-axis voltage command vector V * dq is the voltage command vector in the dq rotating coordinate system.

[0025] d-q axis current vector I dq is the current vector that has been actually detected by the current detection unit 12 and coordinate-transformed into the d-q rotating coordinate system. The estimated magnetic pole position θ^ e is the information obtained by estimating the magnetic pole position of the rotor included in the AC motor 1. The estimated angular velocity ω^ e is the information obtained by estimating the angular velocity of the rotor.

[0026] As methods for estimating the magnetic pole position of the rotor from the speed electromotive force generated while the AC motor 1 is rotating, there are various methods such as an adaptive flux observer and an extended induced voltage observer. Further, the control unit 400 may directly observe the magnetic pole position of the rotor using a position sensor such as an encoder or a resolver. The control unit 400 calculates the angular velocity of the rotor based on the magnetic pole position of the rotor.

[0027] The coordinate conversion unit 17 receives the phase current vector (three-phase current vector) I of the AC motor 1 from the current detection unit 12 uvw . The coordinate conversion unit 17 uvw coordinate-converts the phase current vector I dq into the d-q axis current vector I e . That is, the coordinate conversion unit 17 converts the three-phase current vector into two vectors (d-axis current vector and q-axis current vector) that are current vectors in the rotating two-phase coordinate system. The coordinate conversion unit 17 uses the estimated magnetic pole position θ^ dq for this coordinate conversion. That is, the coordinate conversion unit 17 performs a rotating two-phase conversion based on the estimated magnetic pole position θ^e which is the rotor position information. The coordinate conversion unit 17 outputs the d-q axis current vector I

[0028] The voltage command determination unit 15 determines the voltage command to be applied to the AC motor 1. That is, the voltage command determination unit 15 executes speed control calculation and current control calculation to obtain the d-q axis voltage command vector V dq from the d-q axis current vector I * dqDetermine. The voltage command determination unit 15 determines, for example, the d-axis voltage command vector and the q-axis voltage command vector by decomposing the dq-axis current vector I dq into a d-axis current vector and a q-axis current vector. Then, the voltage command determination unit 15 determines the dq-axis voltage command vector V * dq from the d-axis voltage command vector and the q-axis voltage command vector. The voltage command determination unit 15 determines the dq-axis voltage command vector V * e so that the speed command ω e matches the estimated angular velocity ω^ * dq sent from the rotor position calculation unit 14. The speed command ω * e is a command for the angular velocity of the rotor. The voltage command determination unit 15 obtains the speed command ω * e from the upper program used by the upper device of the drive device 4. The voltage command determination unit 15 outputs the dq-axis voltage command vector V * dq to the rotor position calculation unit 14 and the coordinate conversion unit 16.

[0029] The rotor position calculation unit 14 calculates the position information of the rotor of the AC motor 1 (rotor position information). Specifically, the rotor position calculation unit 14 estimates the estimated magnetic pole position θ^ * dq and the estimated angular velocity ω^ dq from the dq-axis voltage command vector V e and the dq-axis current vector I e .

[0030] When a position sensor for detecting the position of the rotor is arranged in the compressor 3, the rotor position calculation unit 14 may estimate the estimated magnetic pole position θ^ e and the estimated angular velocity ω^ e based on the position of the rotor detected by the position sensor. The rotor position calculation unit 14 outputs the estimated magnetic pole position θ^ e to the coordinate conversion unit 17 and the adder 19. Further, the rotor position calculation unit 14 outputs the estimated angular velocity ω^ e to the voltage command determination unit 15.

[0031] The beatless control unit 18 suppresses the pulsation of the motor current (the current of the AC motor 1) caused by the periodic pulsation of the DC bus voltage V by operating the voltage phase of the voltage command to the inverter 11. The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user. DC The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. dis based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. dq The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. dis The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. b The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. dis The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. DC The beatless control unit 18 extracts the component of the disturbance frequency f included in the dq-axis current vector I based on the disturbance frequency f input by the user, and determines the operation amount (phase change amount) θ of the voltage phase for reducing the extracted component. The disturbance frequency f is the pulsation frequency of the DC bus voltage V. The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. b The beatless control unit 18 outputs the operation amount θ of the voltage phase to the adder 19. b By outputting the operation amount θ of the voltage phase in this way, the beatless control unit 18 operates the voltage phase of the voltage command to the inverter 11, thereby suppressing the pulsation of the motor current. The detailed internal configuration and effects of the beatless control unit 18 will be described later.

[0032] The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. e The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. b The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. eb The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. b The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. e The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. eb The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. eb The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. dis The adder 19 determines the phase angle θ^ by adding the operation amount θ of the voltage phase sent from the beatless control unit 18 to the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14. That is, the adder 19 determines the sum of the operation amount θ of the voltage phase and the estimated magnetic pole position θ^ as the phase angle θ^. The phase angle θ^ is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f. The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16. eb The adder 19 sends the phase angle θ^ to the coordinate conversion unit 16.

[0033] The coordinate conversion unit 16 uses the phase angle θ^ to convert the dq-axis voltage command vector V into a three-phase voltage command vector V. eb The coordinate conversion unit 16 uses the phase angle θ^ to convert the dq-axis voltage command vector V into a three-phase voltage command vector V. * dq The coordinate conversion unit 16 uses the phase angle θ^ to convert the dq-axis voltage command vector V into a three-phase voltage command vector V. *uvw is converted. That is, the coordinate conversion unit 16 is based on the rotor pole position (phase angle θ^ eb ) adjusted to suppress pulsation, and generates a three-phase voltage command vector V * uvw . Specifically, the coordinate conversion unit 16 uses the phase angle θ^ eb to operate the voltage phase of the dq-axis voltage command vector V * dq , and converts the operated dq-axis voltage command vector V * dq into a three-phase voltage command vector V * uvw . The coordinate conversion unit 16 outputs the three-phase voltage command vector V * uvw to the modulation unit 13.

[0034] The modulation unit 13 determines a PWM (Pulse Width Modulation) signal for operating the inverter 11. Specifically, the modulation unit 13 determines a PWM signal based on the DC bus voltage V DC sent from the DC bus voltage detection unit 10 and the three-phase voltage command vector V * uvw sent from the coordinate conversion unit 16, and outputs it to the inverter 11.

[0035] The inverter 11 outputs a voltage corresponding to the PWM signal to the AC motor 1. As a result, the AC motor 1 is driven by the drive device 4. Generally, when the DC reactor 8 or the capacitor 9 is reduced in capacity, the DC bus voltage tends to pulsate greatly. When the input is a three-phase AC power supply, it is known that the disturbance frequency, which is the pulsation frequency of the DC bus voltage, is six times the power supply frequency. Also, when the input is a single-phase AC power supply, it is known that the disturbance frequency, which is the pulsation frequency of the DC bus voltage, is twice the power supply frequency. Furthermore, harmonic pulsations of these integral multiple frequencies occur. Due to such pulsations of the DC bus voltage, pulsations occur in the motor current.

[0036] When viewed from the dq-axis current, the frequency of this current pulsation coincides with the disturbance frequency and the frequencies that are integer multiples of the disturbance frequency. When this current pulsation is observed on the three-phase coordinates, the frequencies of the sum and difference between the disturbance frequency f dis and the frequency f e of the phase current of the AC motor 1 result in current pulsations of |f dis ±f e |. This current pulsation is likely to become prominent when the frequency of the difference |f dis -f e | is small.

[0037] This low-frequency (disturbance frequency f dis ) phase current pulsation caused by the pulsation of the DC bus voltage is called beat vibration, and various countermeasures have been studied for a long time. When the phase current pulsates due to beat vibration, demerits such as deterioration of the motor efficiency due to an increase in the current peak value, a decrease in the maximum output of the AC motor 1 due to the constraints of overcurrent protection, and an increase in the vibration or noise of the AC motor 1 occur.

[0038] The drive device 4 of Embodiment 1 automatically minimizes beat vibration in order to suppress the pulsation of the motor current. The drive device 4 minimizes beat vibration even in the voltage saturation region of the inverter voltage where the amplitude of the voltage command cannot be operated by operating the voltage phase.

[0039] FIG. 2 is a diagram for explaining beat vibration when the drive device according to Embodiment 1 does not perform voltage phase operation. FIG. 3 is a diagram for explaining the principle of suppressing beat vibration by voltage phase operation of the drive device according to Embodiment 1.

[0040] The horizontal axis of the graphs shown in FIGS. 2 and 3 is the d-axis, and the vertical axis is the q-axis. In FIGS. 2 and 3, the voltage that the drive device 4 outputs on average is represented by (v d0 , v q0 ), and the current that the drive device 4 outputs on average is represented by (i d0 , i q0 ). That is, on average, the drive device 4 outputs v d0 and v q0is outputting a voltage, and it is assumed that currents of i d0 and i q0 are flowing through the AC motor 1.

[0041] When the inverter voltage, which is the voltage of the inverter 11, is saturated, the inverter voltage expands and contracts as shown in Fig. 2 due to the pulsation of the DC bus voltage (disturbance voltage VD). As a result, the dq-axis current draws an elliptical locus centered on the point of (i d0 , i q0 ). That is, the current locus Ita, which is the locus of the dq-axis current, becomes an elliptical locus. The larger this elliptical current locus Ita of the dq-axis current becomes, the larger the beat vibration that appears in the phase current becomes.

[0042] In Embodiment 1, since the drive device 4 cannot operate the amplitude of the voltage command in the voltage saturation region of the inverter voltage, it operates the voltage phase to reduce the beat vibration.

[0043] Generally, it is known that if an appropriate change is given to the voltage phase with respect to the dq-axis voltage command, the elliptical locus of the dq-axis current becomes smaller. Although various voltage phase operation type beatless controls have been studied, there has been no study on what kind of voltage phase change (operation amount θ b ) of the voltage phase should be given in order to efficiently reduce the locus of the elliptical current locus Ita of the dq-axis current.

[0044] The drive device 4 efficiently reduces the elliptical current locus Itb of the dq-axis current as shown in Fig. 3 by appropriately changing the voltage phase. In Fig. 3, the case is shown where the drive device 4 changes the voltage phase by the phase change amount Pc, so that the locus of the voltage of the drive device 4 becomes the voltage locus Vt and the elliptical current locus of the dq-axis current becomes the current locus Itb.

[0045] In addition, the drive device 4 drives the AC motor 1 so that the major and minor axis directions of the elliptical current locus Itb of the dq-axis current become the angles desired by the user in order to enhance the effect of the beatless control.

[0046] In Embodiment 1, in order for the drive device 4 to reduce the elliptical current locus Itb of the dq-axis current and set the major and minor axis directions to a desired angle set by the user, the configuration of the beatless control unit 18 is set to the configuration shown in FIG. 4.

[0047] FIG. 4 is a diagram showing the configuration of the beatless control unit included in the drive device according to Embodiment 1. The beatless control unit 18 includes a norm calculation unit 101, a weight coefficient setting unit 102, a pulsation extraction unit 103, and an automatic search unit 104. The dq-axis current vector I dq is input to the norm calculation unit 101, and the disturbance frequency f dis is input from the user to the pulsation extraction unit 103 and the automatic search unit 104.

[0048] The norm calculation unit 101 calculates the norm (absolute value) or the weighted norm of the dq-axis current vector I dq . The beatless control unit 18 only needs to have the weight coefficient setting unit 102 when calculating the weighted norm of the dq-axis current vector I dq , and does not need to have the weight coefficient setting unit 102 when calculating the norm of the dq-axis current vector I dq (when not calculating the weighted norm). The weight coefficient setting unit 102 stores the weight coefficients w1 and w2 described later set by the user, and sets the weight coefficients w1 and w2 to the norm calculation unit 101.

[0049] The weight coefficient w1 is the weight for the d-axis current, and the weight coefficient w2 is the weight for the q-axis current. The weights of the d-axis current and the q-axis current are adjusted according to the ratio of the weight coefficients w1 and w2. There are various types of norms, but the most well-known norm is the L2 norm calculated using the following formula (1).

[0050]

Equation

[0051] However, i in formula (1) dand i q is the dq-axis current (d-axis current and q-axis current). The norm calculation unit 101 calculates the norm |I dq |2 using Equation (1). |I dq |2 corresponds to the absolute value of the dq-axis current vector I dq . Note that the norm calculation unit 101 may use L1 norm, L∞ norm, etc. instead of the L2 norm.

[0052] Further, the norm calculation unit 101 may calculate the weighted norm |I dqw | using the following Equation (2) to which the weighting factors w1, w2 are applied. In this case, the norm calculation unit 101 calculates |I dqw | using the weighting factors w1, w2 stored in the weighting factor setting unit 102.

[0053]

Equation

[0054] The weighting factors w1, w2 in Equation (2) are any values equal to or greater than zero. Note that in Equation (2), instead of i d 2 and i q 2 , i d 3 and i q 3 may be applied, or i d 4 and i q 4 etc. may be applied. Also, |I dq |2 is equal to |I dqw | when w1 = w2 = 1. FIG. 4 shows the configuration of the beatless control unit 18 when the norm calculation unit 101 calculates |I dqw | and outputs it to the pulsation extraction unit 103.

[0055] The beatless control unit 18 according to Embodiment 1 is based on the norm (|I dq |2 or |I dqwReduce the pulsating component of |). The effect obtained by the beatless control changes depending on which norm pulsating component is suppressed by the beatless control unit 18.

[0056] For example, when it is desired to suppress the peak value of the phase current, the beatless control unit 18 makes |I dq Suppress the pulsation of |2. Also, when it is desired to suppress the vibration and noise of the AC motor 1, the beatless control unit 18 sets w1 = 0 and w2 = 1 to suppress the pulsation of the q-axis current. Further, when aiming for an intermediate state between these, the beatless control unit 18 may change the weighting factors w1 and w2 such as w1 = 0.5 and w2 = 0.5. Also, the beatless control unit 18 may change the weighting factors w1 and w2 such as w1 = 0.25 and w2 = 0.75, or may change the weighting factors w1 and w2 such as w1 = 0.75 and w2 = 0.25. Also, in the case where the d-axis current is larger than the q-axis current, the beatless control unit 18 may set w1 = 1 and w2 = 0 to suppress the pulsation of the d-axis current.

[0057] The calculation in the norm calculation unit 101 is for making the major and minor axis directions of the elliptical current locus Itb of the dq-axis currents at an angle desired by the user, and is for effectively applying the beatless control.

[0058] In the weighting factor setting unit 102, the weighting factors w1 and w2 are set according to the purpose of the beatless control (what kind of control effect is desired by the beatless control). The weighting factors w1 and w2 may be arbitrarily set by the user of the drive device 4. Note that, hereinafter, there may be cases where a norm without weighting is described, but the norm may be a weighted norm. Note that the weighting factor setting unit 102 may adjust the weighting factors w1 and w2 based on the dq-axis current vector I dq And the rotational speed of the AC motor 1, etc.

[0059] The pulsation extraction unit 103 is the norm (norm without weighting |I dqw Or weighted norm |I dqwExtract the pulsating component (periodic pulsation) of |). At this time, the frequency components extracted by the pulsation extraction unit 103 are the components of the disturbance frequency f dis and the harmonic components that are integer multiples of the disturbance frequency f dis (fundamental frequency). The pulsation extraction unit 103 may extract the pulsating component of the norm by any extraction method.

[0060] The pulsation extraction unit 103, for example, uses the principle of Fourier series to separate the sin component and the cos component of the pulsation of the norm and extract the pulsating component of the norm. Also, the pulsation extraction unit 103 may extract the pulsating component using a band-pass filter. Hereinafter, the case where the pulsation extraction unit 103 extracts the pulsating component of the norm using the principle of Fourier series will be described.

[0061] Here, the sin component and the cos component of the pulsation of the norm extracted by the pulsation extraction unit 103 are represented by the symbols y sin , y cos respectively. The pulsation extraction unit 103 outputs y sin , y cos to the automatic search unit 104.

[0062] The automatic search unit 104 automatically searches for the operation amount θ dis of the voltage phase such that y sin , y cos is minimized using the disturbance frequency f b . For example, when there is no constraint on the operation amount θ b , y sin = 0 and y cos = 0 are the minimum values of y sin and y cos . Also, when there is a constraint on the operation amount θ b , the minimum values of y sin and y cos are values corresponding to the constraint of the operation amount θ b .

[0063] The automatic search unit 104 may search for the operation amount θ b using any automatic search method. The automatic search unit 104, for example, uses integral control to search for the operation amount θ bSearch for it. Also, the automatic search unit 104 may search for the operation amount θ b using AI (Artificial Intelligence) or machine learning.

[0064] Here, the operation amount θ of the voltage phase to be optimized b will be described in terms of its calculation formula. First, the conversion result of converting the disturbance frequency f dis to the angular frequency is the disturbance angular frequency ω dis . Let ω dis and f dis . The relational expression between them is given by the following equation (3).

[0065]

Equation

[0066] Here, the integration result of integrating ω dis with respect to time t will be represented by the symbol θ dis .

[0067]

Equation

[0068] Here, since f dis can be regarded as a constant, θ dis can be expressed as a linear function of time t. At this time, the operation amount θ of the voltage phase b can be expressed, for example, by the following equation (5).

[0069]

Equation

[0070] In equation (5), x cos , x sin are the cosine component and sine component of the output signal of the beatless control, respectively. In this beatless control, the automatic search unit 104 makes x such that y sin , y cos is minimized.cos and x sin will search for combinations with. Note that using the trigonometric addition theorem, Equation (5) can also be written in the form of the following Equation (6).

[0071] [Mathematics]

[0072] In Equation (6), x is the amplitude of θ b , and δ is the phase difference from cos(θ dis ). Therefore, even if the control unit 400 is configured to search for a combination of x and δ such that y sin , y cos is minimized, the control unit 400 can obtain the same effect as when searching for a combination of x sin , y cos is minimized and a combination of x cos and x sin .

[0073] The reason for aiming to minimize the pulsation of the norm or weighted norm in Embodiment 1 is that the minimization is the best state that can be achieved in the voltage saturation region (inverter overmodulation region) of the inverter voltage. When the DC bus voltage pulsates, pulsations occur in both the d-axis and q-axis currents. However, in order to suppress both pulsations of the d-axis and q-axis currents simultaneously, both the amplitude and phase of the voltage must be manipulated. This is obvious from the perspective of control freedom. In a state where only the phase of the voltage can be controlled, such as during inverter overmodulation, there is only one parameter that the control unit 400 can control. Therefore, in such a situation, the control unit 400 aims to minimize the pulsation of the norm or weighted norm by controlling the phase of the voltage.

[0074] In this way, the control unit 400 minimizes the pulsation of an arbitrary norm or weighted norm by appropriately manipulating the phase of the voltage. However, the operation amount θ of the optimal voltage phase in the sense of minimizing the pulsation bIt varies complexly due to factors such as the complexity of the control plant where the AC motor 1 is arranged, the influence of the motor power factor of the AC motor 1, and the influence of the power supply inductance 6. Therefore, the control unit 400 of Embodiment 1 automatically searches for the operation amount θ of the voltage phase at which the pulsation of any norm or weighted norm is minimized. b

[0075] As a result, the control unit 400 can accurately suppress the pulsation of the phase current due to beat vibration with a simple configuration. Note that the effect of the beatless control varies depending on which norm pulsation is reduced. By suppressing the pulsation of the phase current, the control unit 400 can prevent, for example, deterioration of the motor efficiency due to an increase in the current peak value, a decrease in the maximum output of the AC motor 1 due to the constraints of overcurrent protection, and an increase in the vibration and noise of the AC motor 1.

[0076] FIG. 5 is a flowchart showing the processing procedure of the control process executed by the control unit of the drive device according to Embodiment 1. The control unit 400 acquires the phase current (phase current vector I uvw ) flowing through the AC motor 1 detected by the current detection unit 12 from the current detection unit 12 (step S10). Subsequently, the control unit 400 acquires the DC bus voltage (DC bus voltage V DC ), which is the voltage across the capacitor 9 detected by the DC bus voltage detection unit 10, from the DC bus voltage detection unit 10 (step S20).

[0077] Thereafter, the coordinate conversion unit 17 performs coordinate conversion on the current (step S30). That is, the coordinate conversion unit 17 converts the phase current vector I uvw received from the current detection unit 12 into a dq-axis current vector I e using the estimated magnetic pole position θ^ dq .

[0078] The rotor position calculation unit 14 calculates the rotor position (step S40). As a result, the rotor position calculation unit 14 acquires the position information and speed information of the rotor of the AC motor 1. Specifically, the rotor position calculation unit 14 calculates the dq-axis voltage command vector V * ​dq and the dq-axis current vector I dq From this, the estimated magnetic pole position θ^ which is the rotor position information e and the estimated angular velocity ω^ which is the rotor speed information e are estimated.

[0079] The voltage command determination unit 15 calculates a voltage command for rotating the AC motor 1 at a desired speed and torque (step S50). Specifically, the voltage command determination unit 15 uses the speed command ω * e and the estimated angular velocity ω^ e to calculate the dq-axis voltage command vector V dq from the dq-axis current vector I * dq such that they match.

[0080] The vectorless control unit 18 executes vectorless control calculation (step S60). As a result, the vectorless control unit 18 determines the operation amount θ of the voltage phase b Specifically, the vectorless control unit 18 extracts the component of the disturbance frequency f dq included in the dq-axis current vector I dis and determines the operation amount θ of the voltage phase for reducing the extracted component b .

[0081] The coordinate conversion unit 16 converts the voltage command into a value on the three-phase coordinates (step S70). Specifically, the coordinate conversion unit 16 uses the phase angle θ^ b which is the sum of the operation amount θ of the voltage phase b and the estimated magnetic pole position θ^ eb to convert the dq-axis voltage command vector V * dq into the three-phase voltage command vector V * uvw by coordinate conversion.

[0082] The modulation unit 13 executes modulation calculation (step S80). Specifically, the modulation unit 13 uses the DC bus voltage V DC and the three-phase voltage command vector V * uvwBased on this, a PWM signal is determined. The modulation unit 13 supplies the PWM signal to the inverter 11.

[0083] Next, the operation of the beatless control unit 18 will be described. FIG. 6 is a flowchart showing the processing procedure of the beatless control process executed by the beatless control unit of the drive device according to Embodiment 1.

[0084] In the beatless control unit 18, the weight coefficient setting unit 102 sets the pre-stored weight coefficients w1 and w2 to the norm calculation unit 101 (step S110). The norm calculation unit 101 executes a norm calculation (step S120). That is, the norm calculation unit 101 calculates the norm or weighted norm of the dq-axis current vector I dq or the weighted norm.

[0085] The pulsation extraction unit 103 executes a pulsation extraction operation of the norm or weighted norm calculated by the norm calculation unit 101 (step S130). That is, the pulsation extraction unit 103 extracts the pulsation components included in the norm or weighted norm based on the components of the disturbance frequency f dis and the harmonic components that are integer multiples of f dis . The pulsation extraction unit 103 outputs the sin component and cos component of the pulsation of the norm to the automatic search unit 104 as y sin , y cos respectively.

[0086] The automatic search unit 104 automatically searches for the operation amount θ b of the voltage phase that minimizes the extracted pulsation components (step S140). Specifically, the automatic search unit 104 uses the disturbance frequency f dis to automatically search for the operation amount θ sin of the voltage phase such that y cos is minimized. b

[0087] Subsequently, the hardware configuration of the control unit 400 included in the drive device 4 will be described. FIG. 7 is a diagram showing an example of the hardware configuration for realizing the control unit included in the drive device according to Embodiment 1.

[0088] The control unit 400 is realized by a processor 91, a memory 92, and a peripheral device 93. Note that not only in the first embodiment but also in other embodiments, the control unit 400 and the control units 400C and 400D described later are realized by a processor 91, a memory 92, and a peripheral device 93.

[0089] Each function of the control unit 400 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a control program and stored in the memory 92. In the processing circuit that realizes the control unit 400, the processor 91 reads and executes the control program stored in the memory 92 to realize each function. This control program may be provided by a computer-readable recording medium that records the control program, or may be provided by other means such as a communication medium. It can also be said that the control program is a program that causes the control unit 400 to execute the processing of steps S10 to S80 in FIG. 5.

[0090] The processor 91 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, also referred to as a DSP (Digital Signal Processor)), or a system LSI (Large Scale Integration).

[0091] The memory 92 can exemplify 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 (registered trademark) (Electrically Erasable Programmable Read Only Memory). Further, the memory 92 is not limited thereto and may be a magnetic disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

[0092] The peripheral device 93 is, for example, a PWM pulse generation circuit, an analog-digital conversion circuit, an encoder counter, etc. The PWM pulse generation circuit is arranged in the modulation unit 13. The PWM pulse generation circuit is used for driving the inverter 11 and the AC-DC converter.

[0093] The analog-digital conversion circuit is arranged in the modulation unit 13, the coordinate conversion unit 17, etc. The analog-digital conversion circuit is used for, for example, detecting the DC bus voltage and the phase current of the AC motor 1.

[0094] The encoder counter is arranged in the rotor position calculation unit 14 when the position of the rotor is detected by a position sensor arranged in the compressor 3. The encoder counter is used for, for example, acquiring rotor position information.

[0095] Thus, according to the first embodiment, since the control unit 400 of the drive device 4 calculates the operation amount θ of the voltage phase to minimize the extracted pulsation component, even in the voltage saturation region of the inverter voltage where the amplitude of the voltage command cannot be operated, the pulsation can be reduced as intended. Thereby, the control unit 400 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage without performing complicated control adjustment. b Since the control unit 400 of the drive device 4 calculates the operation amount θ of the voltage phase to minimize the extracted pulsation component, even in the voltage saturation region of the inverter voltage where the amplitude of the voltage command cannot be operated, the pulsation can be reduced as intended. Thereby, the control unit 400 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage without performing complicated control adjustment.

[0096] In addition, since the control unit 400 can effectively suppress beat vibration, the DC reactor 8 and the capacitor 9 can be reduced in size and capacitance. As a result, the manufacturing cost of the drive device 4 can be reduced, and the energy saving performance can be improved.

[0097] In addition, the control unit 400 can prevent deterioration of motor efficiency due to an increase in the current peak value, a decrease in the maximum output of the motor due to constraints on overcurrent protection, an increase in vibration and noise of the AC motor 1, etc. by suppressing beat vibration.

[0098] In addition, the control unit 400 calculates the operation amount θ of the voltage phase to minimize the extracted pulsation component b and controls the inverter 11 using this operation amount θ b Therefore, the effect of reducing current pulsation can be easily stabilized regardless of the operating conditions of the drive device 4 and the installation conditions of the drive device 4.

[0099] Embodiment 2. Next, Embodiment 2 will be described with reference to FIGS. 8 to 12. In Embodiment 2, the difference between the target value r of the pulsation component * and the cos component of the norm and the difference between the target value r of the pulsation component * and the sin component of the norm are rotated to automatically search for the operation amount θ of the voltage phase b .

[0100] FIG. 8 is a diagram showing the configuration of the automatic search unit included in the beatless control unit according to Embodiment 2. The method of automatic search executed by the automatic search unit 104 may be any method, but here, the configuration of the automatic search unit 104 when the automatic search unit 104 uses integral control will be described.

[0101] The automatic search unit 104 includes subtractors 201A and 201B, a rotation calculation unit 202, integral control units (integral controllers) 203A and 203B, an AC restoration unit 204, and a rotation amount adjustment unit 205. The integral control unit 203A is the first integral control unit, and the integral control unit 203B is the second integral control unit. The target value r of the pulsation component *When it is set to zero, the automatic search unit 104 searches for a point where the pulsation component becomes zero. Usually, the target value r of the pulsation component * is set to zero, but the target value r * may be set to a non-zero value (a value other than zero).

[0102] The target value r of the pulsation component, which is stored in advance, is input to the automatic search unit 104 * and y, which is the cos component of the pulsation of the norm or weighted norm cos , and y, which is the sin component sin , and the disturbance frequency f dis are input.

[0103] The subtracter 201A calculates the difference between the target value r of the pulsation component * and y, which is the cos component of the pulsation of the norm or weighted norm cos , and outputs the calculation result as the deviation e of the cos component cos to the rotation calculation unit 202.

[0104] The subtracter 201B calculates the difference between the target value r of the pulsation component * and y, which is the sin component of the pulsation of the norm or weighted norm sin , and outputs the calculation result as the deviation e of the sin component sin to the rotation calculation unit 202.

[0105] The rotation calculation unit 202 performs a rotation calculation on e cos and e sin using the following formula (7). Here, the cos component after the rotation calculation is denoted as e Rcos , and the sin component after the rotation calculation is denoted as e Rsin .

[0106]

Equation

[0107] θ in formula (7) R is the rotation amount of the rotation calculation. The rotation amount θ Ris set in advance by the user in the rotation amount adjustment unit 205. The rotation amount adjustment unit 205 sets the rotation amount θ R in the rotation calculation unit 202. The rotation calculation unit 202 may be arranged inside the pulsation extraction unit 103.

[0108] The integral control unit 203A integrates the deviation e cos corresponding to y Rcos (the rotated cos component), and the integral control unit 203B integrates the deviation e sin corresponding to y Rsin (the rotated sin component). That is, the integral control unit 203A determines x Rcos by performing integral control on e cos , and the integral control unit 203B determines x Rsin by performing integral control on e sin . x cos , x sin are the cos component and the sin component of the output signal of the beatless control respectively. The integral control units 203A and 203B accumulate the error between the target value r * of the pulsation component and the actual value, and perform integral control by adding an amount proportional to this accumulated value to the operation amount θ b of the voltage phase.

[0109] The integral control unit 203A performs integral control so that the rotated cos component e Rcos becomes zero. That is, the integral control unit 203A determines x * from e cos so that the deviation e cos , which is the difference between the target value r Rcos of the pulsation component and the cos component y cos of the norm or weighted norm of the pulsation, becomes zero. That is, the integral control unit 203A determines x cos by performing integral control so that y * approaches the target value r cos of the pulsation component.

[0110] Also, the integral control unit 203B calculates the difference between the target value r * of the pulsation component and the sin component ysin The deviation e, which is the difference from sin is made zero, and x is determined from e. That is, the integral control unit 203B determines x by performing integral control so that y Rsin approaches the target value r of the pulsating component. sin sin * sin

[0111] Here, the automatic search unit 104 uses the integral control units 203A and 203B. However, the automatic search unit 104 may use other control units as long as the control includes an integral element. For example, the automatic search unit 104 may use a control unit that performs PI (Proportional-Integral) control or a control unit that performs PID (Proportional-Integral-Differential) control.

[0112] The AC restoration unit 204 converts the output of the integral control into AC and determines the operation amount θ of the voltage phase. That is, the AC restoration unit 204 calculates the operation amount θ of the voltage phase based on x, x, and f. Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase. By applying f to equations (3) to (5), a sine wave and a cosine wave corresponding to f are derived, and the operation amount θ corresponding to f is derived. b cos sin dis b cos sin dis b dis dis dis b

[0113] ​​​​​​​​​​​​​​​​​FIG. 9 is a diagram showing an operation pattern of a deviation vector when the beatless control unit according to Embodiment 2 executes beatless control in a state where the rotation amount is optimal. FIG. 10 is a diagram showing an operation pattern of a deviation vector when the beatless control unit according to Embodiment 2 executes beatless control in a state where the rotation amount is within a range of less than ±90 degrees from the optimal value. FIG. 11 is a diagram showing an operation pattern of a deviation vector when the beatless control unit according to Embodiment 2 executes beatless control in a state where the rotation amount is away from the optimal value by more than ±90 degrees.

[0114] Rotation amount θ R When it is in a state within a range of less than ±90 degrees from the optimal value, the rotation amount θ R is a case where the absolute value of the difference between and the optimal value is less than 90 degrees. The rotation amount θ R When it is in a state away from the optimal value by more than ±90 degrees, the rotation amount θ R is a case where the absolute value of the difference between and the optimal value is greater than 90 degrees.

[0115] The horizontal axis in FIGS. 9 to 11 is the cos component (e cos ), and the vertical axis is the sin component (e sin ). In FIGS. 9 to 11, the deviation vector locus Et, which is an operation pattern of a deviation vector E (not shown) composed of e cos and e sin when the beatless control unit 18 executes beatless control, is shown. The deviation vector E is a vector directed from the origin to (e cos , e sin ). The beatless control unit 18 controls so that (e cos , e sin ) approaches the origin, that is, the absolute value of the deviation vector E becomes smaller. The deviation vector locus Et has "Start" as the starting point and "Goal" as the ending point. The operation pattern of the deviation vector E by beatless control (the deviation vector locus Et corresponding to the behavior of the control unit 400) can be roughly classified into four types according to the rotation amount θ R .

[0116] The first operation pattern shown in FIG. 9 is when the rotation amount θ R is in an optimal state. When the beatless control unit 18 starts beatless control in this state, e cos and e sin The deviation vector E composed of and approaches the origin at the shortest distance by the action of integral control.

[0117] The second operation pattern shown in FIG. 10 is when the rotation amount θ R is within the range of less than ±90 degrees from the optimal value. At this time, when the beatless control unit 18 starts beatless control, the deviation vector E approaches the origin while drawing a spiral.

[0118] The third operation pattern shown in FIG. 11 is when the rotation amount θ R is more than ±90 degrees away from the optimal value. At this time, when the beatless control unit 18 starts beatless control, the deviation vector E moves away from the origin while drawing a spiral.

[0119] The fourth operation pattern not shown in the figure is when the rotation amount θ R is in the worst state (the state where it is 180 degrees away from the optimal value). At this time, when the beatless control unit 18 starts beatless control, the deviation vector E moves away from the origin in a straight line.

[0120] To the rotation amount adjustment unit 205, a rotation amount θ as close to the optimal value as possible is set by the user in advance. R To the rotation amount adjustment unit 205, for example, a rotation amount θ of less than ±85 degrees from the optimal value R is set.

[0121] Since the beatless control unit 18 according to the second embodiment has the automatic search unit 104 shown in FIG. 8, if the rotation amount θ R is appropriately given by the rotation amount adjustment unit 205, the deviation e cos , e sin can be controlled to zero. Usually, since the target value r * of the pulsating component is set to zero, the deviation ecos , e sin becomes zero, y which is the cos component of the pulsation of the dq-axis current norm or the weighted norm cos , and y which is the sin component sin also becomes zero.

[0122] Note that the rotation amount θ R is not limited to being set in advance by the user, and may be adjusted while operating the AC motor 1. In this case, the dq-axis current vector I dq , the rotation amount θ R is adjusted based on the rotation speed of the AC motor 1, etc. Also, the rotation amount θ R may be determined by some additional information given from outside the drive device 4. The rotation amount adjustment unit 205 stores the determined rotation amount θ R .

[0123] Next, the operation of the automatic search unit 104 will be described. FIG. 12 is a flowchart showing the processing procedure of the automatic search process executed by the automatic search unit of the drive device according to Embodiment 2. The automatic search unit 104 automatically searches for the point where the pulsation of the norm or the weighted norm is minimized in the following procedure.

[0124] The subtractor 201A calculates the deviation e cos of the cos component, and the subtractor 201B calculates the deviation e sin of the sin component (step S210). The rotation amount adjustment unit 205 sets the rotation amount θ R to the rotation calculation unit 202 (step S220).

[0125] The rotation calculation unit 202 performs a rotation calculation of the vector using the rotation amount θ R (step S230). Specifically, the rotation calculation unit 202 applies e cos , e sin , and the rotation amount θ R to Equation (7) to calculate the rotated cos component e Rcos and the rotated sin component e Rsin .

[0126] The integral control units 203A and 203B execute integral control operations (step S240). Specifically, the integral control unit 203A integrates e after the rotation operation to determine x, which is the cosine component of the output signal of the beatless control. Rcos And the integral control unit 203B integrates e after the rotation operation to determine x, which is the sine component of the output signal of the beatless control. cos The integral control units 203A and 203B execute integral control operations (step S240). Specifically, the integral control unit 203A integrates e after the rotation operation to determine x, which is the cosine component of the output signal of the beatless control. Rsin And the integral control unit 203B integrates e after the rotation operation to determine x, which is the sine component of the output signal of the beatless control. sin And the integral control unit 203B integrates e after the rotation operation to determine x, which is the sine component of the output signal of the beatless control.

[0127] The AC restoration unit 204 executes an AC restoration operation (step S250). Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase. cos The AC restoration unit 204 executes an AC restoration operation (step S250). Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase. sin The AC restoration unit 204 executes an AC restoration operation (step S250). Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase. dis The AC restoration unit 204 executes an AC restoration operation (step S250). Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase. b The AC restoration unit 204 executes an AC restoration operation (step S250). Specifically, the AC restoration unit 204 applies x, x, and f to equations (3) to (5) to calculate the operation amount θ of the voltage phase.

[0128] As described above, according to the second embodiment, when the rotation amount θ is in an appropriate state (the rotation amount θ is within the range of less than ±90 degrees from the optimum value), the control unit 400 of the drive device 4 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage without performing complicated control adjustment. R As described above, according to the second embodiment, when the rotation amount θ is in an appropriate state (the rotation amount θ is within the range of less than ±90 degrees from the optimum value), the control unit 400 of the drive device 4 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage without performing complicated control adjustment. R As described above, according to the second embodiment, when the rotation amount θ is in an appropriate state (the rotation amount θ is within the range of less than ±90 degrees from the optimum value), the control unit 400 of the drive device 4 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage without performing complicated control adjustment.

[0129] Embodiment 3. Next, Embodiment 3 will be described with reference to FIGS. 13 to 21. In the method described in Embodiment 2, when the rotation amount θ is in an appropriate state to some extent, the beat vibration caused by the pulsation of the DC bus voltage can be effectively suppressed. In Embodiment 3, when the rotation amount θ is in an inappropriate state, it is corrected to an appropriate state. R Next, Embodiment 3 will be described with reference to FIGS. 13 to 21. In the method described in Embodiment 2, when the rotation amount θ is in an appropriate state to some extent, the beat vibration caused by the pulsation of the DC bus voltage can be effectively suppressed. In Embodiment 3, when the rotation amount θ is in an inappropriate state, it is corrected to an appropriate state. R Next, Embodiment 3 will be described with reference to FIGS. 13 to 21. In the method described in Embodiment 2, when the rotation amount θ is in an appropriate state to some extent, the beat vibration caused by the pulsation of the DC bus voltage can be effectively suppressed. In Embodiment 3, when the rotation amount θ is in an inappropriate state, it is corrected to an appropriate state.

[0130] FIG. 13 is a diagram showing the configuration of the beatless control unit included in the drive device according to Embodiment 3. Among the components in FIG. 13, the components that achieve the same functions as those of the beatless control unit 18 in Embodiment 1 shown in FIG. 4 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0131] The drive device 4 of Embodiment 3 has a beatless control unit 18A instead of the beatless control unit 18 as compared with the drive device 4 of Embodiment 1. The beatless control unit 18A has a search failure detection unit 105 in addition to the components that the beatless control unit 18 has. Further, the beatless control unit 18A has an automatic search unit 104A instead of the automatic search unit 104 as compared with the beatless control unit 18.

[0132] When the search failure detection unit 105 detects an unintended increase in y cos and y sin , it determines that the beatless control is in an abnormal state (the rotation amount θ R is in an inappropriate state), and outputs a search direction correction signal, which is a signal for correcting the search direction, to the automatic search unit 104A. The search direction correction signal is a signal for correcting the search direction (the direction of the deviation vector E) of the operation amount θ R by adjusting the rotation amount θ b . The search direction corresponds to the search process of the operation amount θ b for making the deviation vector E zero. In other words, the search direction corresponds to the search process of x cos and x sin for making the cos component (x cos ) and the sin component (x sin ) of the output signal of the beatless control approach the optimum values. When the search failure detection unit 105 detects that both y cos and y sin have increased, it outputs a search direction correction signal to the automatic search unit 104A.

[0133] When the automatic search unit 104A receives the search direction correction signal, it corrects the search direction. The beatless control unit 18A discovers a search direction for reducing y cos and y sin by this correction operation, and finally makes the deviation vector E zero.

[0134] FIG. 14 is a diagram showing an operation pattern of a deviation vector when the beatless control unit according to Embodiment 3 executes beatless control. The horizontal axis in FIG. 14 is the cos component (e cos ), and the vertical axis is the sin component (e sin ). In FIG. 14, a deviation vector locus Et, which is an operation pattern of a deviation vector E composed of e cos and e sin when the beatless control unit 18A executes beatless control, is shown. The deviation vector locus Et has "Start" as the starting point and "Goal" as the ending point.

[0135] When beatless control is being performed, if the automatic search for the operation amount θ cos of the voltage phase at which y sin , which is the cos component of the pulsation of the norm or weighted norm of the dq-axis current, and y b , which is the sin component, becomes minimum, is not properly performed, y cos and y sin increase. The beatless control unit 18A according to Embodiment 3 detects such an increase in y cos and y sin .

[0136] In the beatless control unit 18A, when the search failure detection unit 105 detects an unintended increase in y cos and y sin , it determines that the beatless control is in an abnormal state and outputs a search direction correction signal.

[0137] When the automatic search unit 104A receives the search direction correction signal, it corrects the search direction. The search failure detection unit 105 continues to output the search direction correction signal while it determines that the beatless control is in an abnormal state. Also, when the search failure detection unit 105 determines that the beatless control is in a normal state, it stops outputting the search direction correction signal. The automatic search unit 104A continues to correct the search direction until it no longer receives the search direction correction signal. By this correction operation, y cos and y sinIt decreases, and the deviation vector E becomes zero. As a result, the drive device 4 can surely suppress the beat vibration under any operating conditions.

[0138] Here, the concept of the search direction corrected by the beatless control unit 18A will be described. FIG. 15 is a first explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 3. FIG. 16 is a second explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 3. FIG. 17 is a third explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 3. FIG. 18 is a fourth explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 3.

[0139] In FIGS. 15 to 18, an image of the search direction corrected by the beatless control unit 18A is shown. The horizontal axis in FIGS. 15 to 18 is the cos component (e cos , e Rcos , x cos ), and the vertical axis is the sin component (e sin , e Rsin , x sin ). In FIGS. 15 to 17, compared with FIGS. 9 to 11, a deviation vector locus ERt which is an operation pattern (locus) of the deviation vector ER (not shown) after the rotation operation, an output signal locus xt which is an operation pattern of the output signal vector x (not shown), and a sector region representing an image of the search direction are added. The deviation vector ER after the rotation operation is a vector of the rotation result obtained by rotating the deviation vector E before the rotation operation by the rotation operation unit 202. The output signal locus xt is the locus of the output signal vector x of the beatless control.

[0140] The deviation vector ER is a vector directed from the origin to (e Rcos , e Rsin ), and the deviation vector E is, as described above, a vector directed from the origin to (e cos , e sin ). Here, the case where the ideal values of the deviation vector E before the rotation operation and the deviation vector ER after the rotation operation are zero (the origin) will be described.

[0141] In FIGS. 15 to 18, the image of the search direction is shown by a fan-shaped figure (fan-shaped area) imitating the human visual field. When the center of the fan-shaped area is the position of the output signal vector x at a certain time, the arc portion of the fan-shaped area is the image of the forward visual field at that time.

[0142] Specifically, in FIG. 15, the image of the search direction is shown by the search direction image SD1, and in FIG. 16, the images of the search direction are shown by the search direction images SD2 and SD3. Also, in FIG. 17, the images of the search direction are shown by the search direction images SD4, SD5, and SD6, and in FIG. 18, the images of the search direction are shown by the search direction images SD7 and SD8.

[0143] The search direction image SD1 shown in FIG. 15 is the search direction image when the rotation amount θ R is the optimal value. When the rotation amount θ R is optimal, the search direction image SD1 does not need to be changed from the start to the completion of the search.

[0144] The search direction images SD2 and SD3 shown in FIG. 16 are the search direction images when the rotation amount θ R is an appropriate value. The search direction image SD2 is the image of the search direction at the start of the search, and the search direction image SD3 is the image of the search direction when the search can be completed. That is, the search direction image SD3 is the search direction image after a specific time has elapsed since the start of the search using the search direction image SD2.

[0145] The search direction images SD4, SD5, and SD6 shown in FIG. 17 are the search direction images when the rotation amount θ RIt is an image of the search direction when the value is inappropriate. The search direction image SD4 is the image of the search direction at the start of the search, the search direction image SD5 is the image of the search direction during the search, and the search direction image SD6 is the image of the search direction when the search fails. That is, the search direction image SD5 is the search direction image after a specific time has elapsed since the start of the search using the search direction image SD4. The search direction image SD6 is the search direction image after a specific time has elapsed since the search using the search direction image SD5.

[0146] In FIGS. 15 to 17, the trajectory of the deviation vector E before the rotation operation as it attempts to go from the point of the initial value Es of the deviation vector E to the point of the ideal value Ei of the deviation vector E (the origin) is illustrated as the deviation vector trajectory Et.

[0147] Also, in FIGS. 15 to 17, the trajectory of the deviation vector ER after the rotation operation as it attempts to go from the point of the initial value ERs of the deviation vector ER to the point of the ideal value Ei of the deviation vector ER (the origin) is illustrated as the deviation vector trajectory ERt.

[0148] Also, in FIG. 18, as shown in FIG. 17, the rotation amount θ R is inappropriate and the search fails. After the rotation amount θ R is adjusted, the trajectory of the deviation vector ER as it attempts to go from the point of the initial value ERs of the deviation vector ER to the point of the ideal value Ei of the deviation vector ER (the origin) is illustrated as the deviation vector trajectory ERt2.

[0149] Here, it is assumed that if the ideal value of the output signal vector x can be searched, the deviation vector E before the rotation operation and the deviation vector ER after the rotation operation can be set to zero. However, the beatless control unit 18A cannot know in advance where the ideal value of the output signal vector x is in the figure.

[0150] The beatless control unit 18A can only determine whether or not it has succeeded in searching for the ideal value of the output signal vector x by observing the deviation vectors E and ER. However, the search range of the output signal vector x is limited. That is, the output signal vector x is provided with a searchable range SR which is the range where search is possible. When the ideal value of the output signal vector x is not within the searchable range SR, the deviation vectors E and ER cannot be set to zero. Therefore, the beatless control unit 18A searches for the output signal vector x that minimizes the deviation vectors E and ER within the searchable range SR.

[0151] The initial value xs of the output signal vector x is an arbitrary value and is often set to zero, but here it is set to a non-zero value for the convenience of drawing. Also, the initial values of the deviation vectors E and ER are set to arbitrary non-zero values. In FIGS. 15 to 17, the initial value of the deviation vector E is denoted as the initial value Es, and the initial value of the deviation vector ER is denoted as the initial value ERs. Note that the initial value ERs of the deviation vector ER may be the same as the initial value Es of the deviation vector E.

[0152] In FIG. 15, the beatless control unit 18A according to Embodiment 3 R represents the operation patterns of the deviation vectors E and ER and the output signal vector x when beatless control is executed when the rotation amount θ

[0153] The deviation vector locus Et which is the locus of the deviation vector E and the deviation vector locus ERt which is the locus of the deviation vector ER after rotation operation are R different in phase by the amount of rotation θ R When the rotation amount θ is in an ideal state, the deviation vectors E and ER move from the initial values Es and ERs toward the ideal value Ei (the origin), which is the ideal point of the deviation vectors E and ER, along the shortest distance. For this purpose, the output signal vector x also needs to move from the initial value xs toward the ideal value xi, which is the ideal point of the output signal vector x, along the shortest distance.

[0154] Since the output signal vector x is a vector obtained by integrating the deviation vector ER, if the direction of the deviation vector ER does not match the moving direction of the ideal output signal vector x, it is impossible for the output signal vector x to move at the shortest distance. In this case, the parameter for adjusting the direction of the deviation vector ER is the rotation amount θ R Since it is, the beatless control unit 18A can move the deviation vectors E and ER toward the ideal value Ei at the shortest distance if the rotation amount θ R is set to an optimal state.

[0155] Since the output signal vector x moves along the direction of the deviation vector ER seen from the origin, the direction of the deviation vector ER seen from the origin can be considered as the search direction of the output signal vector x. Alternatively, it can be said that the search direction of the beatless control is approximately the traveling direction of the output signal vector x.

[0156] The sector area (search direction image SD1) shown in FIG. 15 corresponds to the visual field when the rotation amount θ R is the optimal value. In this case, since the ideal value xi of the output signal vector x is on the extension line of the search direction, the search for the ideal value xi of the output signal vector x succeeds smoothly.

[0157] The sector areas (search direction images SD2 and SD3) shown in FIG. 16 correspond to the visual field when the rotation amount θ R is within the range of ±90 degrees from the optimal value. In this case, there is a slight deviation between the direction of the ideal value xi of the output signal vector x and the search direction. Since a slight deviation in the search direction is allowed by the internal integral control (integral control by the integral control units 203A and 203B) in the beatless control unit 18A, the beatless control unit 18A can finally reach the ideal value Ei for the deviation vectors E and ER. However, the deviation vectors E and ER will decrease in a spiral shape by the amount that the output signal vector x does not move toward the ideal value xi of the output signal vector x at the shortest distance.

[0158] The sector areas (search direction images SD4, SD5, and SD6) shown in FIG. 17 are for the rotation amount θR This corresponds to the field of view when it is more than ±90 degrees away from the optimum value. In this case, there is a large deviation between the direction of the ideal value xi of the output signal vector x and the search direction. In this case, since the deviation vectors E and ER do not decrease as intended even when the output signal vector x is changed, the search direction is not uniquely determined, and the output signal vector x is manipulated so that the deviation vectors E and ER go to a point different from the ideal value Ei. For this reason, the beatless control unit 18A increases the deviation vectors E and ER in a trajectory such that they draw a spiral, and the beatless control fails.

[0159] In FIG. 17, the points of the deviation vectors E and ER when it is detected that the search has failed are indicated by the deviation vectors Ef and ERf, respectively. Also, in FIG. 17, the point of the output signal vector x when it is detected that the search has failed is indicated by the arrival value xf.

[0160] In Embodiment 3, in preparation for the case where the deviation vectors E and ER perform the operation as shown in FIG. 17, the beatless control unit 18A is provided with a search failure detection unit 105 that detects that the search for the optimum value of the rotation amount θ R has failed. The reason for the failure in the search in the operation described with reference to FIG. 17 is that the search direction was inappropriate (in other words, the rotation amount θ R was inappropriate). When the search fails, the beatless control unit 18A detects the failure of the search and corrects the search direction, so that eventually the optimum value of the rotation amount θ R can be successfully searched for.

[0161] In FIG. 18, an operation image is shown when, after the search for the optimum value of the rotation amount θ R has failed, the search direction is corrected and the search is executed again. That is, the behavior shown in FIG. 18 is that when the beatless control unit 18A detects the failure of the search, it adjusts the rotation amount θ R and the rotation amount θ RThis is the behavior when reset to an appropriate value. Note that, similar to Fig. 17 in Fig. 18, the points of the deviation vectors E and ER when it is detected that the search has failed are indicated by the deviation vectors Ef and ERf, respectively.

[0162] In Fig. 18, the rotation amount before correction is denoted as the rotation amount Bθ R and the rotation amount after correction is denoted as the rotation amount Aθ R Also, in Fig. 18, for the search direction image SD7 when it is detected that the search has failed, the beatless control unit 18A indicates the search direction image after adjusting the rotation amount Bθ R by the search direction image SD8. When the beatless control unit 18A adjusts the rotation amount Bθ R , the rotation amount becomes the rotation amount Aθ R and the deviation vector ER and the search direction after the rotation operation change.

[0163] In Fig. 18, the locus of the output signal vector x after the rotation amount Bθ R is adjusted is indicated by the locus xt2. Also, in Fig. 18, the locus of the deviation vector ER rotationally calculated by the adjusted rotation amount Aθ R is indicated by the deviation vector locus ERt2. Further, in Fig. 18, the locus of the deviation vector E rotationally calculated by the adjusted rotation amount Aθ R is indicated by the deviation vector locus Et2.

[0164] If, by adjusting the rotation amount Bθ R , the rotation amount Aθ R becomes the optimal value, the ideal value xi of the output signal vector x comes on the extension line of the search direction, so the search for the optimal value is completed smoothly.

[0165] Note that, in Fig. 18, for the sake of explanation, the case where the rotation amount θ R is adjusted once and the rotation amount θ R is adjusted to the optimal value has been described. However, in reality, since the optimal value of the rotation amount θ R is unknown, the adjustment of the rotation amount θ R is performed little by little in multiple times by the integral control units 203A and 203B.

[0166] Further, the beatless control unit 18A constantly corrects the rotation amount θ during the operation of the beatless control by a method combining the outer product operation and PID control described later. R Such correction of the rotation amount θ R In the correction process of, the deviation vector E may approach the origin through a complex deviation vector locus Et as shown in FIG. 14. Further, as shown in FIG. 18, after the correction of the rotation amount θ R the deviation vector E may also head toward the origin along a linear deviation vector locus Et2.

[0167] In beatless control, it is unknown where the ideal value xi of the output signal vector x is located. If the output signal vector x is operated in an inappropriate direction, beat vibration will increase. Therefore, it is necessary to carefully search for the ideal value xi of the output signal vector x. For this reason, in Embodiment 3, the beatless control unit 18A appropriately corrects the search direction of the beatless control so that the output signal vector x can surely reach the ideal value xi.

[0168] FIG. 19 is a diagram showing the configuration of the automatic search unit included in the beatless control unit according to Embodiment 3. Among the components in FIG. 19, the components that achieve the same functions as the automatic search unit 104 of Embodiment 1 shown in FIG. 8 are denoted by the same reference numerals, and duplicate explanations are omitted.

[0169] The automatic search unit 104A of Embodiment 3 has a rotation amount adjustment unit 206 instead of the rotation amount adjustment unit 205 compared to the automatic search unit 104 of Embodiment 2. The rotation amount adjustment unit 206 receives a search direction correction signal from the search failure detection unit 105. When the rotation amount adjustment unit 206 receives the search direction correction signal, it adjusts the rotation amount θ R and outputs the adjusted rotation amount θ R to the rotation operation unit 202.

[0170] By what method does the rotation amount adjustment unit 206 adjust the rotation amount θ Rmay be adjusted. The rotation amount adjustment unit 206 adjusts the rotation amount θ, for example, by a method combining the outer product operation and PID control described later. R The rotation amount adjustment unit 206 may also automatically search for the rotation amount θ using AI or machine learning. R

[0171] The rotation operation unit 202 receives the rotation amount θ from the rotation amount adjustment unit 206. The rotation operation unit 202 performs a rotation operation on e R and e R using the rotation amount θ received from the rotation amount adjustment unit 206. cos sin

[0172] Here, an example of the adjustment method of the rotation amount θ will be described. FIGS. 20 to 22 are diagrams showing the first behavior of the deviation vector when the beatless control unit according to Embodiment 3 automatically searches for the operation amount of the voltage phase. FIG. 21 is a diagram showing the second behavior of the deviation vector when the beatless control unit according to Embodiment 3 automatically searches for the operation amount of the voltage phase. FIG. 22 is a diagram showing the third behavior of the deviation vector when the beatless control unit according to Embodiment 3 automatically searches for the operation amount of the voltage phase. R

[0173] The horizontal axes of FIGS. 20 to 22 are the cos components (e cos ), and the vertical axes are the sin components (e sin ). In FIGS. 20 to 22, the behavior of the deviation vector E composed of e b and e cos when the automatic search unit 104A automatically searches for the operation amount θ of the voltage phase is schematically shown. sin

[0174] The automatic search unit 104A can determine whether the automatic search for the operation amount θ of the voltage phase is being appropriately performed by examining the deviation vector E and the time differential vector (d / dt)E of the deviation vector E. Hereinafter, the time differential vector (d / dt)E of the deviation vector E may be referred to as the time differential vector (d / dt)E. b

[0175] ​​​​​​ When the deviation vector E and the time derivative vector (d / dt)E are out of phase as in the first behavior of the deviation vector E shown in FIG. 20, the automatic search unit 104A determines that the automatic search is being performed well. Also, when the direction of the time derivative vector (d / dt)E is inside (the origin side) with respect to the vertical line of the deviation vector E as in the second behavior of the deviation vector E shown in FIG. 21, the automatic search unit 104A determines that the automatic search is being performed appropriately to some extent.

[0176] When the direction of the time derivative vector (d / dt)E is outside with respect to the vertical line of the deviation vector E as in the third behavior of the deviation vector E shown in FIG. 22, the automatic search unit 104A determines that the automatic search is not being performed appropriately.

[0177] If the state of the deviation vector E shown in FIG. 22 is left unchanged, the beatless control becomes unstable and diverges. Therefore, the automatic search unit 104A adjusts the rotation amount θ so that the deviation vector E becomes the state shown in FIG. 20 or FIG. 21. R to correct.

[0178] Note that when the direction of the time derivative vector (d / dt)E is inside with respect to the vertical line of the deviation vector E as shown in FIG. 21, the automatic search unit 104A may correct the rotation amount θ so that the direction of the time derivative vector (d / dt)E further turns inside. R to correct.

[0179] The automatic search unit 104A evaluates whether the beatless control is being performed appropriately with a quantitative numerical value (evaluation value) in order to correct the rotation amount θ. The automatic search unit 104A corrects the rotation amount θ with a correction amount according to the evaluation value. R to correct. R to correct.

[0180] FIG. 23 is a diagram for explaining an evaluation value for the automatic search unit according to Embodiment 3 to evaluate whether the beatless control is being performed appropriately. The horizontal axis of FIG. 23 is the cos component, and the vertical axis is the sin component.

[0181] FIG. 23 shows an example of the definition of the evaluation value. The automatic search unit 104A evaluates the validity of the operation of the beatless control, for example, by using the cross product (the area of the parallelogram formed by two vectors) of the deviation vector E and the time derivative vector (d / dt)E of the deviation vector E. Here, the evaluation value for evaluating whether the beatless control is appropriately performed is C d as shown. The cross product of the deviation vector E and the time derivative vector (d / dt)E of the deviation vector E is C d as follows.

[0182] The automatic search unit 104A makes the correction amount of the rotation amount θ smaller as the area of the parallelogram formed by the deviation vector E and the time derivative vector (d / dt)E of the deviation vector E is smaller. Thereby, as the angle formed by the deviation vector E and the time derivative vector (d / dt)E approaches 180 degrees or 0 degrees, the correction amount of the rotation amount θ R becomes smaller. That is, the automatic search unit 104A makes the correction amount of the rotation amount θ R larger as the angle formed by the deviation vector E and the time derivative vector (d / dt)E approaches 90 degrees. R

[0183] FIG. 24 is a diagram showing the configuration of the rotation amount adjustment unit included in the automatic search unit according to Embodiment 3. The rotation amount adjustment unit 206 of Embodiment 3 includes an outer product calculation unit 300, a dead zone 305, and a PID control unit 306.

[0184] The outer product calculation unit 300 includes pseudo differentiators 302A and 302B, multipliers 303A and 303B, and a subtracter 304. The deviation e cos is input to the rotation amount adjustment unit 206 from the subtracter 201A, and the deviation e sin is input from the subtracter 201B.

[0185] Note that the symbol s shown in FIG. 24 is a Laplacian operator. For the rotation amount adjustment unit 206, a differentiator without a low-pass filter (LPF: Low Pass Filter) may be used instead of the pseudo-differentiators 302A and 302B. However, in FIG. 24, the case where the pseudo-differentiators 302A and 302B with a low-pass filter added to remove differential noise are used will be described.

[0186] The outer product calculation unit 300 calculates C, which is an evaluation value, by the above-described outer product calculation. In the outer product calculation unit 300, the deviation e d is input to the pseudo-differentiator 302A and the multiplier 303B, and the deviation e cos is input to the pseudo-differentiator 302B and the multiplier 303A. sin

[0187] The pseudo-differentiator 302A differentiates the deviation e cos with respect to time t and passes it through a low-pass filter to calculate (d / dt)e cos and outputs it to the multiplier 303A. The multiplier 303A multiplies e sin and (d / dt)e cos and outputs the multiplication result to the subtractor 304.

[0188] The pseudo-differentiator 302B differentiates the deviation e sin with respect to time t and passes it through a low-pass filter to calculate (d / dt)e sin and outputs it to the multiplier 303B. The multiplier 303B multiplies e cos and (d / dt)e sin and outputs the multiplication result to the subtractor 304.

[0189] The subtractor 304 calculates the evaluation value C d by subtracting the multiplication result output from the multiplier 303B from the multiplication result output from the multiplier 303A. The subtractor 304 outputs C d to the dead zone 305.

[0190] The dead zone 305 is for the rotation amount θ RStop the adjustment. Rotation amount θ R If the adjustment of R is performed more than necessary, it is not preferable in terms of the stability of the beatless control. Therefore, after the beatless control converges to the final value, the rotation amount adjustment unit 206 of Embodiment 3 stops the adjustment of the rotation amount θ R by the dead zone 305. Note that the use of the dead zone 305 by the rotation amount adjustment unit 206 is an example, and other circuits or the like other than the dead zone 305 may be used as a mechanism for stopping the adjustment of the rotation amount θ R .

[0191] The PID control unit 306 performs PID control on the signal output from the dead zone 305 and outputs the rotation amount θ R to the rotation calculation unit 202. Note that the adjustment of the rotation amount θ R may be performed using any circuit. The adjustment of the rotation amount θ R may be performed, for example, by a PI control unit that executes PI control. If better control results can be expected, the rotation amount θ R may be adjusted using another type of control unit or AI

[0192] When the rotation amount adjustment unit 206 changes the rotation amount θ R , the operation of the beatless control is optimized, and the evaluation value C d decreases. When the evaluation value C d decreases to a specific value, the change in the rotation amount θ R stops. At this time, since the rotation amount θ R is an appropriate value, the deviation vector E converges to zero

[0193] Next, the operation of the rotation amount adjustment unit 206 will be described. FIG. 25 is a flowchart showing the processing procedure of the rotation amount adjustment process executed by the rotation amount adjustment unit according to Embodiment 3

[0194] The outer product calculation unit 300 calculates C d , which is an evaluation value for determining whether the beatless control is being performed appropriately, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the deviation e of the cos component calculated by the subtracter 201Acos and the deviation e calculated by the subtractor 201B sin Based on this and... d calculate C, which is the evaluation value.

[0195] The dead zone 305 of the rotation amount adjustment unit 206 executes dead zone processing (step S330). The PID control unit 306 of the rotation amount adjustment unit 206 performs PID control calculation (step S340), and adjusts the rotation amount θ so that the evaluation value C d becomes zero. R is adjusted.

[0196] As described above, according to the third embodiment, when the rotation amount θ of the control unit 400 of the drive device 4 is in an inappropriate state, the inappropriate state is automatically detected, and the rotation amount θ R is corrected. Therefore, without performing complicated control adjustment, the beat vibration caused by the pulsation of the DC bus voltage can be effectively suppressed under any operating conditions. R is corrected. Therefore, without performing complicated control adjustment, the beat vibration caused by the pulsation of the DC bus voltage can be effectively suppressed under any operating conditions.

[0197] Embodiment 4 Next, Embodiment 4 will be described with reference to FIG. 26. In Embodiment 4, by parallelizing the beatless control, the disturbance frequency f dis (fundamental frequency) and the harmonic components of the pulsation frequency are suppressed simultaneously.

[0198] FIG. 26 is a diagram showing the configuration of the beatless control unit provided in the drive device according to Embodiment 4. Among the components in FIG. 26, the components that achieve the same functions as the beatless control unit 18 of Embodiment 1 shown in FIG. 4 are denoted by the same reference numerals, and redundant explanations are omitted.

[0199] The drive device 4 of Embodiment 4 has a beatless control unit 18B instead of the beatless control unit 18 as compared with the drive device 4 of Embodiment 1. The beatless control unit 18B includes a pulsation extraction unit 103B instead of the pulsation extraction unit 103 and an automatic search unit 104B instead of the automatic search unit 104 as compared with the beatless control unit 18.

[0200] In the beatless control unit 18B, the control system (suppression system) of the disturbance frequency f dis and the control system of the harmonic component are paralleled. That is, the beatless control unit 18B of the fourth embodiment has a pulsation extraction unit 103B and an automatic search unit 104B that parallelize the control systems of the disturbance frequency f dis and the harmonic component. Generally, since the pulsation (pulsation component) of the DC bus voltage includes a harmonic component, the dq-axis current of the AC motor 1 is affected by the harmonic component. Therefore, the drive device 4 of the fourth embodiment suppresses the disturbance frequency f dis , which is the fundamental frequency, and the harmonic component simultaneously in order to reduce the pulsation of the norm or weighted norm of the dq-axis current.

[0201] For example, when it is desired to simultaneously suppress the disturbance frequency f dis and the disturbance frequency Nf dis that is N times (N is an integer of 2 or more) of the disturbance frequency f dis , the pulsation extraction unit 103B and the automatic search unit 104B are input with the disturbance frequency f dis and the disturbance frequency Nf dis . The operation amount θ b of the voltage phase in this case is defined as in the following formula (8).

[0202]

Equation

[0203] In formula (8), x cosN and x sinN are the cosNf component and the sinNf component of the output signal of the beatless control, respectively. The pulsation extraction unit 103B extracts, for example, the pulsation components, namely, the sin1F component, the cos1F component, the sinNf component, and the cosNf component from the norm or weighted norm calculated by the norm calculation unit 101. Here, the extracted pulsation components will be represented by the symbols ysin, ycos, ysinN, and ycosN, respectively.

[0204] The pulsation extraction unit 103B extracts, as the pulsation components of the norm, the components of the fundamental frequency, ysin and ycos, and the harmonic components, ysinN and ycosN. The automatic search unit 104B searches for a combination of x cos , x sin , x cosN , x sinN such that ysin, ycos, ysinN, and ycosN are simultaneously minimized. That is, the automatic search unit 104B searches for an operation amount that simultaneously minimizes the fundamental frequency and the harmonic components. The automatic search unit 104B may search for the combination by any search method. The automatic search unit 104B searches, for example, by the search methods described in Embodiments 1 to 3.

[0205] In Embodiment 4, the case of parallelizing the control systems of the fundamental wave and the harmonic wave was described. However, when it is desired to simultaneously suppress harmonic components of a plurality of orders, parallelization may be performed on the beatless control unit 18B in the same manner as the method described with reference to FIG. 26.

[0206] For example, when it is desired to simultaneously suppress the disturbance frequency f dis , the disturbance frequency Nf dis , and the disturbance frequency M times (M is an integer different from N and M is 2 or more) of the disturbance frequency f dis , that is, Mf dis , the pulsation extraction unit 103B and the automatic search unit 104B are input with the disturbance frequency f dis , the disturbance frequency Nf dis , and the disturbance frequency Mf dis . The pulsation extraction unit 103B extracts, for example, the sin1F component, the cos1F component, the sinNf component, the cosNf component, the sinMf component, and the cosMf component, which are pulsation components, from the norm or the weighted norm calculated by the norm calculation unit 101. The automatic search unit 104B searches for a combination of the cos1f component, the sin1f component, the cosNf component, the sinNf component, the cosMf component, and the sinM component of the output signal of the beatless control such that each of the extracted pulsation components is minimized.

[0207] Thus, according to the fourth embodiment, since the control unit 400 of the drive device 4 parallelizes the beatless control, even when the pulsation of the DC bus voltage contains a large harmonic component, the beat vibration can be effectively suppressed without performing complicated control adjustment.

[0208] Embodiment 5. Next, Embodiment 5 will be described with reference to FIGS. 27 to 29. In Embodiment 5, when the DC reactor 8 and the LC (L-C) resonance frequency of the capacitor 9 approach the disturbance frequency f dis the range for searching the operation amount θ b of the voltage phase is limited.

[0209] FIG. 27 is a diagram showing the configuration of the drive device according to Embodiment 5. Among the components in FIG. 27, the components that achieve the same functions as those of the drive device 4 of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant explanations are omitted.

[0210] The drive device 4C of Embodiment 5 has a control unit 400C instead of the control unit 400 as compared with the drive device 4 of Embodiment 1. The control unit 400C has a beatless control unit 18C instead of the beatless control unit 18 as compared with the control unit 400.

[0211] In the drive device 4C, the DC bus voltage detection unit 10 is connected to the beatless control unit 18C and the modulation unit 13. The beatless control unit 18C receives the DC bus voltage V DC which is information on the DC bus voltage from the DC bus voltage detection unit 10.

[0212] There is a power supply impedance between the drive device 4C and the AC power supply 5. The power supply inductance 6 which is the inductance component of the power supply impedance is an unknown parameter that changes depending on the installation environment of the drive device 4C, the power supply environment, the operating conditions of surrounding electrical equipment (hereinafter referred to as peripheral electrical equipment), and the like. When the power supply inductance 6, the DC reactor 8, and the capacitor 9 resonate, a large pulsation may occur in the DC bus voltage.

[0213] The disturbance frequency f targeted by the beatless control dis When the LC resonance frequency of the DC reactor 8 and the capacitor 9 approaches the disturbance frequency f, if an attempt is made to minimize the pulsation of the dq-axis current norm or the weighted norm, the pulsation width of the DC bus voltage may increase significantly. In such a case, if the beatless control is over-applied, the dq-axis current waveform may be disturbed instead. Such a phenomenon is likely to be a problem when the power source impedance is larger than the impedance on the drive device 4C side.

[0214] In Embodiment 5, the drive device 4C detects that the LC resonance frequency of the DC reactor 8 and the capacitor 9 approaches the disturbance frequency f and the pulsation of the DC bus voltage increases. When the drive device 4C detects an increase in the pulsation of the DC bus voltage, it restricts the range (automatic search range) for searching the operation amount θ dis of the voltage phase to minimize the norm pulsation. In this way, the drive device 4C obtains a good current waveform by suppressing the operation of the beatless control. b Figure 28 is a diagram showing the configuration of the beatless control unit included in the drive device according to Embodiment 5. Among the components in Figure 28, the components that achieve the same functions as the beatless control unit 18 of Embodiment 1 shown in Figure 4 are given the same reference numerals, and redundant explanations are omitted.

[0215] The beatless control unit 18C of Embodiment 5 has a search range restriction unit 106 in addition to the components included in the beatless control unit 18 of Embodiment 1. Further, the beatless control unit 18C has an automatic search unit 104C instead of the automatic search unit 104 as compared with the beatless control unit 18 of Embodiment 1.

[0216] The search range restriction unit 106 receives the DC bus voltage V

[0217] which is information on the DC bus voltage, from the DC bus voltage detection unit 10. The search range restriction unit 106, based on the DC bus voltage V DC restricts the operation amount θ DC based on the DC bus voltage V bCalculate the search range and output it to the automatic search unit 104C.

[0218] When the pulsation amplitude of the DC bus voltage has increased excessively, specifically when the pulsation amplitude of the periodic pulsation of the DC bus voltage exceeds a specific threshold, the search range limitation unit 106 determines that the LC resonance and the beatless control interfere with each other and limits the search range to a specific range. The LC resonance is an inductor-capacitor resonance between the AC power supply 5 that supplies power to the inverter 11 and the inverter 11. The automatic search unit 104C automatically searches for the point where the norm or weighted norm of the dq-axis current is minimized (the operation amount θ of the voltage phase b ) within the search range indicated by the search range limitation unit 106. As a result, the beatless control unit 18C can suppress the beat vibration while avoiding the influence of the LC resonance.

[0219] FIG. 29 is a diagram showing the configuration of the automatic search unit included in the beatless control unit according to Embodiment 5. Among the components in FIG. 29, the components that achieve the same functions as the beatless control unit 18 of Embodiment 1 shown in FIG. 8 are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0220] In addition to the components included in the automatic search unit 104 of Embodiment 1, the automatic search unit 104C of Embodiment 5 has a limit value adjustment unit 207. Further, the automatic search unit 104C has integral control units 203C and 203D instead of the integral control units 203A and 203B as compared with the automatic search unit 104 of Embodiment 1.

[0221] The limit value adjustment unit 207 calculates the limit values to be set in the integral control units 203C and 203D based on the search range sent from the search range limitation unit 106. That is, the limit value adjustment unit 207 converts the search range information into the limit values of the integral control units 203C and 203D. The limit value adjustment unit 207 outputs the calculated limit values to the integral control units 203C and 203D. Thereby, the limit values applied by the integral control units 203C and 203D are adjusted.

[0222] In the case of the search method using integral control, the automatic search unit 104C can limit the search range by adjusting the limit values of integrators such as the integral control units 203C and 203D. The integral control units 203C and 203D operate according to the limit values received from the limit value adjustment unit 207. The integral control units 203C and 203D execute the same processing as the integral control units 203A and 203B within the range of the limit values.

[0223] As described above, according to the fifth embodiment, the control unit 400 of the drive device 4 restricts the operation of the beatless control so as not to over-apply the beatless control when the LC resonance frequency is close to the disturbance frequency f dis targeted by the beatless control. Thereby, the control unit 400 can prevent an excessive increase in the pulsation of the DC bus voltage or the deterioration of the dq-axis current pulsation accompanying the increase in the pulsation without performing complicated control adjustment.

[0224] Sixth Embodiment. Next, the sixth embodiment will be described with reference to FIGS. 30 and 31. In the sixth embodiment, a drive device (drive device 4D described later) improves the search speed of the automatic search using additional information.

[0225] In the drive devices 4 and 4C described in the first to fifth embodiments, when the frequency targeted by the beatless control (disturbance frequency f dis ) and the LC resonance frequency are sufficiently separated, the pulsation of an arbitrary norm or weighted norm can be minimized by appropriately operating the voltage phase. In these drive devices 4 and 4C, the operation amount θ b of the optimal voltage phase for minimizing the pulsation varies complexly due to the complexity of the control plant in which the AC motor 1 is arranged, the influence of the motor power factor of the AC motor 1, the influence of the power supply inductance 6, etc., so that the time required for the automatic search may become long depending on the operating conditions.

[0226] In Embodiment 6, using at least one piece of additional information including the characteristics of the control plant in which the AC motor 1 is arranged, the motor power factor of the AC motor 1, the estimated value of the power supply inductance 6, and the status (installation status, connection status, operating status) of the peripheral electrical equipment arranged around the AC motor 1, a direction to be preferentially searched (preferred search direction) is set.

[0227] The peripheral electrical equipment is, for example, equipment (such as other drive devices) connected in parallel with the drive device 4D to the AC power supply 5. In this case, the peripheral electrical equipment and the drive device 4D are connected in parallel to the AC power supply 5. The power supply inductance 6 is different between the case where the peripheral electrical equipment is connected to the AC power supply 5 and the case where the peripheral electrical equipment is not connected to the AC power supply 5. For this reason, in Embodiment 6, information on the status of the peripheral electrical equipment may be included in the additional information.

[0228] Note that the additional information may be other information than the above-described information as long as it is information beneficial for the beatless control. The additional information may be sent from an arithmetic device (not shown) arranged outside the drive device 4D to the drive device 4D, or may be calculated inside the drive device 4D.

[0229] FIG. 30 is a diagram showing the configuration of the drive device according to Embodiment 6. Among the components of FIG. 30, components that achieve the same functions as those of the drive device 4 of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0230] The drive device 4D of Embodiment 6 has a control unit 400D instead of the control unit 400 as compared with the drive device 4 of Embodiment 1. The control unit 400D has a beatless control unit 18D instead of the beatless control unit 18 as compared with the control unit 400.

[0231] The beatless control unit 18D receives additional information from the outside. The additional information may be sent from a computing device (not shown) arranged outside the drive device 4D to the drive device 4D, or may be calculated inside the drive device 4D. The beatless control unit 18D determines the priority search direction based on the additional information.

[0232] FIG. 31 is a diagram showing the configuration of the beatless control unit included in the drive device according to Embodiment 6. Among the components in FIG. 31, the components that achieve the same functions as the beatless control unit 18 in Embodiment 1 shown in FIG. 4 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0233] The beatless control unit 18D in Embodiment 6 has a priority search direction indicator 107 in addition to the components that the beatless control unit 18 in Embodiment 1 has. Also, the beatless control unit 18D has an automatic search unit 104D instead of the automatic search unit 104 as compared with the beatless control unit 18 in Embodiment 1.

[0234] The priority search direction indicator 107 determines the priority search direction based on the additional information, and instructs the determined priority search direction to the automatic search unit 104D. In the case of the automatic search method using integral control described in Embodiments 2 to 5, the beatless control unit 18D can change the priority search direction by changing the rotation amount θ R Thereby, the beatless control unit 18D can suppress the current pulsation in a short time by instructing the priority search direction based on the additional information.

[0235] As described above, according to Embodiment 6, since the control unit 400 of the drive device 4 instructs the priority search direction based on the additional information, it is possible to effectively suppress the beat vibration caused by the pulsation of the DC bus voltage in a short time without performing complicated control adjustment.

[0236] Embodiment 7. Next, Embodiment 7 will be described with reference to FIG. 32. In Embodiment 7, the drive devices 4, 4C, and 4D described in Embodiments 1 to 6 are applied to a refrigeration cycle device. Note that any of the drive devices 4, 4C, and 4D may be applied to the refrigeration cycle device. Hereinafter, a case where the drive device 4 is applied to the refrigeration cycle device will be described as an example.

[0237] FIG. 32 is a diagram showing the configuration of the refrigeration cycle device according to Embodiment 7. Among the components in FIG. 32, the components that achieve the same functions as the drive device 4 and the compressor 3 in Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0238] The refrigeration cycle device 900 according to Embodiment 7 includes a compressor drive system 800. The compressor drive system 800 includes a drive device 4 having a control unit 400 and a compressor 3 incorporating the AC motor 1 in Embodiment 1. The refrigeration cycle device 900 also includes a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, an outdoor heat exchanger 910, and a refrigerant pipe 912.

[0239] The refrigeration cycle device 900, which is a refrigeration cycle application device, can be applied to products equipped with a refrigeration cycle such as an air conditioner, a refrigerator, a freezer, and a heat pump water heater. In the compressor drive system 800, the compressor 3, the drive device 4, the four-way valve 902, the indoor heat exchanger 906, the expansion valve 908, and the outdoor heat exchanger 910 are connected via the refrigerant pipe 912.

[0240] Inside the compressor 3, a compression mechanism 904 for compressing the refrigerant and an AC motor 1 for operating the compression mechanism 904 are provided. The compression mechanism 904 corresponds to the mechanical device 2 described in Embodiment 1. The refrigeration cycle device 900 can perform a heating operation or a cooling operation by switching the operation of the four-way valve 902. The compression mechanism 904 is driven by an AC motor 1 that is variably speed-controlled.

[0241] During the heating operation, as shown by the solid-line arrow, the refrigerant is pressurized and sent out by the compression mechanism 904, and returns to the compression mechanism 904 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.

[0242] During the cooling operation, as shown by the dashed-line arrow, the refrigerant is pressurized and sent out by the compression mechanism 904, and returns to the compression mechanism 904 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.

[0243] During the 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 the cooling operation, the outdoor heat exchanger 910 acts as a condenser to release heat, the indoor heat exchanger 906 acts as an evaporator, and absorbs heat. The expansion valve 908 depressurizes and expands the refrigerant.

[0244] Thus, according to the seventh embodiment, even in the voltage saturation region of the inverter voltage, the pulsation can be reduced as intended. Therefore, the refrigeration cycle device 900 can prevent deterioration of the motor efficiency due to an increase in the current peak value, a decrease in the maximum output of the motor due to restrictions on overcurrent protection, vibration and noise increase of the AC motor 1, etc. by suppressing the beat vibration.

[0245] In addition, since the control unit 400 can effectively suppress the beat vibration, the DC reactor 8 and the capacitor 9 can be reduced in size and capacity. Thereby, the manufacturing cost of the refrigeration cycle device 900 can be reduced, and the energy-saving performance can be improved.

[0246] The configurations shown in the above embodiments are examples, and it is possible to combine with other known technologies, it is also possible to combine the embodiments with each other, and it is also possible to omit or change a part of the configuration without departing from the gist.

Description of Reference Numerals

[0247] 1 AC motor, 2 mechanical device, 3 compressor, 4, 4C, 4D drive device, 5 AC power supply, 6 power supply inductance, 7 diode rectifier, 8 DC reactor, 9 capacitor, 10 DC bus voltage detection unit, 11 inverter, 12 current detection unit, 13 modulation unit, 14 rotor position calculation unit, 15 voltage command determination unit, 16, 17 coordinate conversion unit, 18, 18A~18D beatless control unit, 19 adder, 91 processor, 92 memory, 93 peripheral device, 101 norm calculation unit, 102 weight coefficient setting unit, 103, 103B pulsation extraction unit, 104, 104A~104D automatic search unit, 105 search failure detection unit, 106 search range limitation unit, 107 priority search direction indication unit, 201A, 201B, 304 subtracter, 202 rotation calculation unit, 203A~203D integral control unit, 204 AC restoration unit, 205, 206 rotation amount adjustment unit, 207 limit value adjustment unit, 300 outer product calculation unit, 302A, 302B pseudo differentiator, 303A, 303B multiplier, 305 dead band, 306 PID control unit, 400, 400C, 400D control unit, 800 compressor drive system, 900 refrigeration cycle device, 902 four-way valve, 904 compression mechanism, 906 indoor heat exchanger, 908 expansion valve, 910 outdoor heat exchanger, 912 refrigerant pipe, E, ER deviation vector, Et, ERt deviation vector locus, Ita, Itb current locus, Pc phase change amount, VD disturbance voltage, Vt voltage locus.

Claims

1. A drive device that drives an AC motor using an inverter, A current detection unit for detecting the current flowing through the AC motor, A rotor position calculation unit calculates rotor position information, which is information about the position of the rotor of the AC motor, A voltage command determination unit determines a voltage command based on the current vector of the current and the rotor position information, A beatless control unit that suppresses the current pulsation caused by periodic pulsation of the DC bus voltage by manipulating the voltage phase of the voltage command, Equipped with, The aforementioned beatless control unit is A norm calculation unit that calculates the norm of the current vector, A pulsation extraction unit separates and extracts the pulsation component of the norm into a cosine component and a sine component, An automatic search unit that searches for the amount of voltage phase manipulation that minimizes the pulsating component, It has, The beatless control unit manipulates the voltage phase using the manipulated amount, The automatic search unit, The manipulated variable that minimizes the cosine component and the sine component is searched for. A rotation calculation unit that performs rotation calculations on the cosine component and the sine component, A first integral control unit that integrates the rotated cosine component, A second integral control unit that integrates the rotated sine component, An AC restoration unit calculates the manipulated variable based on the integrated cosine component, the integrated sine component, and the disturbance frequency which is the pulsation frequency of the DC bus voltage. Equipped with, A drive device characterized by the following features.

2. The aforementioned beatless control unit is The system further includes a search failure detection unit that, upon detecting an increase in the cosine component and the sine component, outputs a search direction correction signal to the automatic search unit, which is a signal that corrects the search direction of the manipulated variable by adjusting the rotation amount of the rotation calculation. The automatic search unit, The system further comprises a rotation amount adjustment unit that adjusts the amount of rotation in the rotation calculation upon receiving the aforementioned search direction correction signal. The rotation calculation unit performs the rotation calculation using the adjusted amount of rotation. The drive device according to feature 1.

3. The pulsation extraction unit is, The fundamental frequency component and harmonic components are extracted as the pulsation components of the aforementioned norm. The automatic search unit, The manipulated variable is searched for in which the fundamental frequency and the harmonic components are simultaneously minimized. The drive device according to feature 1.

4. The aforementioned beatless control unit is The system further includes a search range limiting unit that restricts the search range of the manipulated variable to a specific range when the pulsation amplitude of the periodic pulsation exceeds a threshold. The drive device according to feature 1.

5. The aforementioned beatless control unit is The system further includes a priority search direction indicator that determines a priority search direction, which is the direction in which the manipulated variable is searched preferentially, using additional information that includes at least one piece of information: the characteristics of the control plant in which the AC motor is located, the motor power factor of the AC motor, the power supply inductance which is the inductance component of the power supply impedance between the AC power supply that supplies power to the inverter, and the condition of the electrical equipment arranged around the AC motor. The drive device according to feature 1.

6. The automatic search unit searches for the manipulated quantity using artificial intelligence or machine learning. The drive device according to feature 1.

7. The norm is a weighted norm that is weighted with respect to the d-axis current and the q-axis current. The drive device according to feature 1.

8. A first coordinate transformation unit transforms the three-phase current vector of the current detected by the current detection unit into an axial current vector of a rotating two-phase coordinate system, which is the current vector, based on the rotor position information. A second coordinate transformation unit converts the voltage command, whose voltage phase has been manipulated by the aforementioned manipulated amount, into a three-phase voltage command vector. Furthermore, The voltage command determination unit generates the voltage command of the three-phase voltage command vector based on the axis current vector. The beatless control unit searches for the manipulated variable based on the axial current vector. The drive device according to feature 1.

9. A drive device according to any one of claims 1 to 8, A compressor driven by the aforementioned AC motor, Equipped with, A compressor drive system characterized by the following:

10. The compressor drive system is provided according to claim 9. A refrigeration cycle device characterized by the following features.

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