Drive device, compressor drive system, and refrigeration cycle device

Abstract

A drive device (4) that drives an alternating current motor (1) by means of an inverter (11) includes a current detection unit (12) that detects the current flowing through the alternating current motor, a rotor position calculation unit (14) that calculates rotor position information, which is information on the position of the rotor of the alternating current 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 pulsation of the current caused by periodic pulsation of the DC bus voltage by operating the voltage phase of the voltage command. The beatless control unit has a power factor information calculation unit that calculates power factor information, which is information on the power factor of the alternating current motor, and operates the voltage phase based on the power factor information and the pulsation component of the norm of the current vector.

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. In addition, a reactor is often inserted on the AC - DC converter side for the purpose of power factor improvement and boosting. For this driving device, for the purpose of cost reduction, miniaturization and downsizing of the capacitor and the reactor have been studied.

[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, a low - frequency current pulsation called beat vibration occurs. When the phase current pulsates due to beat vibration, demerits such as deterioration of 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 techniques 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 integrally controls 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 driving 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, a drive device according to 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 which is information on the position of a rotor included in the AC motor. Further, the drive device according to the present disclosure includes a voltage command determination unit that determines a voltage command based on a current vector of the current and the rotor position information, and a beatless control unit that suppresses pulsation of a current caused by periodic pulsation of a DC bus voltage by operating a voltage phase of the voltage command. The beatless control unit has a power factor information calculation unit that calculates power factor information which is information on a power factor of the AC motor, and operates the voltage phase based on the power factor information and a pulsation component of a norm of the current vector.

Advantages of the Invention

[0010] The drive device according to the present disclosure has an effect that pulsation can be reduced as intended even in a voltage saturation region of an 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 driving device according to Embodiment 1. The driving 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 driving 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 inductor 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 is described, but the driving device 4 of Embodiment 1 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 another type of AC-DC converter may be used when power factor improvement or boosting is required.

[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 a 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 both ends of the capacitor 9 as the DC bus voltage V DC and outputs it to the control unit 400. The inverter 11 converts the 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 beatless 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] The control unit 400 obtains the angular difference between the fixed two-phase coordinate and the rotating two-phase coordinate in order to perform control in the rotating two-phase coordinate system. The drive device 4 of Embodiment 1 has a dq-axis voltage command vector V * dq and a dq-axis current vector Idq From this, the estimated magnetic pole position θ^ e and the estimated angular velocity ω^ e are estimated. 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] The dq-axis current vector I dq is the current vector actually detected by the current detection unit 12 and coordinate-converted into the dq rotating coordinate system. The estimated magnetic pole position θ^ e is the information obtained by estimating the magnetic pole position of the rotor provided 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 a method 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 uvw of the AC motor 1 from the current detection unit 12. The coordinate conversion unit 17 uvw converts the phase current vector I dq into the dq-axis current vector I eis used. That is, the coordinate conversion unit 17 performs a rotational two-phase conversion based on the estimated magnetic pole position θ^ which is the rotor position information. e The coordinate conversion unit 17 outputs the dq-axis current vector I dq to the rotor position calculation unit 14, the voltage command determination unit 15, and the vectorless control unit 18.

[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 determine the dq-axis voltage command vector V dq from the dq-axis current vector I * dq For example, by vector control, the voltage command determination unit 15 decomposes the dq-axis current vector I dq into a d-axis current vector and a q-axis current vector to determine a d-axis voltage command vector and a q-axis voltage command 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 is the same as the estimated angular velocity ω^ sent from the rotor position calculation unit 14. The speed command ω * dq is a command for the angular velocity of the rotor. The voltage command determination unit 15 acquires 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 * e to the rotor position calculation unit 14, the vectorless control unit 18, and the coordinate conversion unit 16. * dq

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

[0030] In addition, when a position sensor for detecting the position of the rotor is arranged in the compressor 3, the rotor position calculation unit 14 estimates 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. Also, 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 DC 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 dis included in the dq-axis current vector I dq based on the disturbance frequency f dis input by the user, and determines the operation amount (phase change amount) θ b of the voltage phase for reducing the extracted component. At this time, the beatless control unit 18 calculates the power factor angle φ, which is the phase difference between the dq-axis voltage command vector V * dq and the dq-axis current vector I dq , and utilizes the power factor angle φ for beatless control, which is one of the features of the drive device 4 of the first embodiment. The disturbance frequency f dis is the pulsation frequency of the DC bus voltage V DC . The beatless control unit 18 outputs the operation amount θ b of the voltage phase to the adder 19. In this way, the beatless control unit 18 operates the voltage phase of the voltage command to the inverter 11 by outputting the operation amount θ b of the voltage phase, 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 adds the estimated magnetic pole position θ^ sent from the rotor position calculation unit 14 e to the operation amount θ of the voltage phase sent from the beatless control unit 18 b to determine the phase angle θ^ eb That is, the adder 19 determines the sum of the operation amount θ of the voltage phase b and the estimated magnetic pole position θ^ e as the phase angle θ^ eb The phase angle θ^ eb is the magnetic pole position of the rotor adjusted to suppress the pulsation corresponding to the disturbance frequency f dis The adder 19 sends the phase angle θ^ eb to the coordinate conversion unit 16.

[0033] The coordinate conversion unit 16 uses the phase angle θ^ eb to convert the dq-axis voltage command vector V * dq into the three-phase voltage command vector V * uvw That is, the coordinate conversion unit 16 generates the three-phase voltage command vector V eb based on the magnetic pole position (phase angle θ^ * uvw ) of the rotor adjusted to suppress the pulsation. Specifically, the coordinate conversion unit 16 operates the voltage phase of the dq-axis voltage command vector V eb using the phase angle θ^ * dq and converts the operated dq-axis voltage command vector V * dq into the 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 uses the DC bus voltage V sent from the DC bus voltage detection unit 10 DCand the three-phase voltage command vector V sent from the coordinate conversion unit 16 * uvw Based on this, a PWM signal is determined and output 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 V DC 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 V DC , becomes six times the power supply frequency. Also, in the case of a single-phase AC power supply, it is known that the disturbance frequency, which is the pulsation frequency of the DC bus voltage V DC , becomes twice the power supply frequency. Furthermore, harmonic pulsations of these integral multiple frequencies occur. Due to such pulsations of the DC bus voltage V DC , pulsations occur in the motor current.

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

[0037] This low-frequency (disturbance frequency f DC ) phase current pulsation caused by the pulsation of the DC bus voltage V dis 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 according to Embodiment 1 automatically minimizes the beat vibration in order to suppress the pulsation of the motor current. The drive device 4 minimizes the 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 the 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 the beat vibration by the 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 voltages of v d0 and v q0 , and it is assumed that currents of i d0 and i q0 flow 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 (disturbance voltage VD) of the DC bus voltage V DC . 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 the 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, the drive device 4 operates the voltage phase in order 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 studies have been conducted on such voltage phase operation type beatless control, in order to efficiently reduce the elliptical current locus Ita of the dq-axis current, it has not been studied what kind of voltage phase change (the operation amount θ of the voltage phase) b ) should be given.

[0044] The drive device 4 efficiently reduces the elliptical current locus Itb of the dq-axis current by appropriately changing the voltage phase, as shown in FIG. 3. In FIG. 3, the case is shown where the drive device 4 changes the voltage phase by the phase change amount Pc, 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] Further, 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 make the major and minor axis directions the desired angles set by the user, the configuration of the beatless control unit 18 is set to the configuration shown in FIG. 6 described later.

[0047] The point of what kind of voltage phase change should be given in order to efficiently reduce the locus of the dq-axis current ellipse will be further described in detail. FIG. 4 is a diagram for explaining the voltage phase operation performed when the current vector is in a lagging phase with respect to the voltage vector in the drive device according to Embodiment 1. FIG. 5 is a diagram for explaining the voltage phase operation performed when the current vector is in a leading phase with respect to the voltage vector in the drive device according to Embodiment 1.

[0048] The horizontal axis of the graphs shown in FIGS. 4 and 5 is the d-axis, and the vertical axis is the q-axis. FIGS. 4 and 5 show examples of the phase relationships between voltage and current due to differences in operating conditions. In FIGS. 4 and 5, the voltage limit, which is a voltage constraint, is denoted as voltage limit VL.

[0049] The operating conditions of the AC motor 1 are diverse. For example, as shown in FIG. 4, there may be cases where the current vector lags behind the voltage vector in phase, and as shown in FIG. 5, there may be cases where the current vector leads the voltage vector in phase. The direct torque control is a control that aims to reduce the locus of the dq-axis current vector i dq0 by applying a phase change to the voltage command vector corresponding to the average dq-axis voltage vector v dq0 and giving the dq-axis voltage change amount vector Δv dq to the average dq-axis voltage vector v dq . However, the angle of the dq-axis voltage change amount vector Δv dq and the angle of the current vector vary depending on the operating conditions. Therefore, in order to obtain the desired ripple reduction effect, it is necessary to change the voltage phase operation method between the case of FIG. 4 and the case of FIG. 5.

[0050] In FIGS. 4 and 5, the changes in the locus of the dq-axis current vector i dq when direct torque control is performed using the power factor angle φ are shown. In FIG. 4, the locus of the dq-axis current vector i dq before direct torque control is denoted as locus Ib1, and the locus of the dq-axis current vector i dq after direct torque control is denoted as locus Ia1. In FIG. 5, the locus of the dq-axis current vector i dq before direct torque control is denoted as locus Ib2, and the locus of the dq-axis current vector i dq after direct torque control is denoted as locus Ia2.

[0051] For example, when trying to reduce the pulsation of the absolute value of the current vector, in the example of FIG. 4, the main focus is on suppressing the current pulsation mainly in the q-axis direction, while in the example of FIG. 5, the main focus is on suppressing the current pulsation in the d-axis direction. Even when performing beatless control for the same purpose in this way, depending on the operating conditions, which direction of current pulsation to suppress changes.

[0052] Furthermore, considering also from the viewpoints of vibration and noise, it becomes even more difficult to determine which direction of current should be suppressed. For this reason, it is desirable to operate the voltage phase so that the major and minor axis directions of the elliptical current locus Ita of the dq-axis currents become a desired angle, but the point of what voltage phase change (the operation amount θ of the voltage phase b ) should be given has not been studied. In Embodiment 1, in order to make the current locus Ita have a desired shape and major and minor axis directions, the beatless control unit 18 is configured as shown in FIG. 6.

[0053] FIG. 6 is a diagram showing the configuration of the beatless control unit provided in the drive device according to Embodiment 1. The beatless control unit 18 includes a norm calculation unit 101, a weighting coefficient setting unit 102, a pulsation extraction unit 103, a pulsation suppression unit 104, and a power factor information calculation unit 107. The dq-axis current vector I dq is input to the norm calculation unit 101 and the power factor information calculation unit 107, and the disturbance frequency f dis is input to the pulsation extraction unit 103 and the pulsation suppression unit 104 by the user. Further, the dq-axis voltage command vector V * dq is input to the power factor information calculation unit 107 from the voltage command determination unit 15.

[0054] 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 weighting coefficient setting unit 102 when calculating the weighted norm of the dq-axis current vector I dq , and the dq-axis current vector I dqWhen calculating the norm (when not calculating the weighted norm), the weight coefficient setting unit 102 may not be provided. The weight coefficient setting unit 102 stores the weight coefficients w1 and w2, which will be described later and are set by the user, and sets the weight coefficients w1 and w2 in the norm calculation unit 101.

[0055] 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, and the most well-known norm is the L2 norm calculated using the following equation (1).

[0056]

Equation

[0057] However, in Equation (1), i d and i q are the dq-axis currents (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 the L1 norm, L∞ norm, etc. instead of the L2 norm.

[0058] In addition, the norm calculation unit 101 may calculate the weighted norm |I dqw | using the following Equation (2) to which the weight coefficients w1 and w2 are applied. In this case, the norm calculation unit 101 calculates |I dqw | using the weight coefficients w1 and w2 stored in the weight coefficient setting unit 102.

[0059]

Equation

[0060] The weight coefficients w1 and w2 in Equation (2) can be any values greater than or equal to zero. Note that in Equation (2), id 2 and i q 2 Instead of, 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 when w1 = w2 = 1 dqw |. FIG. 6 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.

[0061] The beatless control unit 18 of Embodiment 1 reduces the pulsation component of the norm (|I dq |2 or |I dqw |) calculated by the norm calculation unit 101. The effect obtained by the beatless control changes depending on which norm pulsation component the beatless control unit 18 suppresses.

[0062] For example, when it is desired to suppress the peak value of the phase current, the beatless control unit 18 greatly suppresses the pulsation of |I dq |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 and suppresses the pulsation of the q-axis current. Also, when the beatless control unit 18 aims for an intermediate state between these, the weighting factors w1 and w2 may be changed 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.

[0063] The operation in the norm calculation unit 101 is an operation for setting the major and minor axes directions of the elliptical current locus Itb of the dq-axis currents to an angle desired by the user, and is an operation for effectively applying the beatless control.

[0064] In the weighting coefficient setting unit 102, the weighting coefficients w1 and w2 are set according to the purpose of the beatless control (what control effect is desired by the beatless control). The weighting coefficients w1 and w2 may be arbitrarily set by the user of the drive device 4. In the following, there may be cases where an unweighted norm is described, but the norm may be a weighted norm. Note that the weighting coefficient setting unit 102 may adjust the weighting coefficients w1 and w2 based on the dq-axis current vector I dq , the rotational speed of the AC motor 1, etc.

[0065] The pulsation extraction unit 103 extracts the pulsation component (periodic pulsation) of the norm (the unweighted norm |I dqw | or the weighted norm |I dqw |) calculated by the norm calculation unit 101. The frequency components extracted by the pulsation extraction unit 103 at this time are the components of the disturbance frequency (fundamental frequency) f dis and the harmonic components that are integer multiples of the disturbance frequency f dis . The pulsation extraction unit 103 may extract the pulsation component of the norm by any extraction method.

[0066] The pulsation extraction unit 103 separates, for example, the sin component and the cos component of the pulsation of the norm using the principle of Fourier series to extract the pulsation component of the norm. Also, the pulsation extraction unit 103 may extract the pulsation component using a band-pass filter. In the following, the case where the pulsation extraction unit 103 extracts the pulsation component of the norm using the principle of Fourier series will be described.

[0067] 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 pulsation suppression unit 104.

[0068] The power factor information calculation unit 107 calculates the power factor angle φ, which is an example of power factor information, from the dq-axis voltage command vector V * dq and the dq-axis current vector I dq using the following equation (3).

[0069]

Equation

[0070] However, ∠ in Equation (3) is a symbol representing the phase angle of the vector, and arctan2 means a four-quadrant arctangent operation function. The power factor information calculation unit 107 outputs the calculated power factor angle φ to the pulsation suppression unit 104.

[0071] The pulsation suppression unit 104 calculates the operation amount θ of the voltage phase such that y sin y cos is reduced. The pulsation suppression unit 104 automatically searches for the operation amount θ of the voltage phase such that y b y sin y cos is minimized, for example, using the power factor angle φ. The specific method of this calculation will be described later. Thus, the drive device 4 of Embodiment 1 improves the performance of the beatless control using the power factor angle φ. b

[0072] Note that the drive device 4 may improve the performance of the beatless control using the power factor cosφ instead of the power factor angle φ. Also, when either the phase of the dq-axis voltage command vector V * dq or the dq-axis current vector I dq can be regarded as substantially constant, the drive device 4 may use the dq-axis voltage command vector V * dq and the dq-axis current vector I dq ​The phase may be utilized to improve the performance of the beatless control. Hereinafter, the information used by the drive device 4 for improving the performance of the beatless control is referred to as power factor information. The power factor information may include at least one of the phase of the power factor angle φ, the power factor cos φ, the dq-axis voltage command vector V * dq and the dq-axis current vector I dq as long as it includes at least one of the phases.

[0073] FIG. 7 is a diagram showing the configuration of a power factor information calculation unit included in the beatless control unit according to Embodiment 1. The power factor information calculation unit 107 includes an angle calculation unit 401A, an angle calculation unit 401B, and a subtractor 402. The dq-axis voltage command vector V * dq is input to the angle calculation unit 401A, and the dq-axis current vector I dq is input to the angle calculation unit 401B.

[0074] The angle calculation unit 401A calculates the angle ∠V * dq which is the angle of the dq-axis voltage command vector V * dq , and the angle calculation unit 401B calculates the angle ∠I dq which is the angle of the dq-axis current vector I dq . The subtractor 402 calculates the difference (angle difference) between ∠V * dq and ∠I dq , and outputs the power factor angle φ which is the calculation result.

[0075] Here, the calculation performed by the pulsation suppression unit 104 will be described in detail. FIG. 8 is a diagram showing the configuration of the pulsation suppression unit included in the beatless control unit according to Embodiment 1. The pulsation suppression unit 104 rotates 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 to calculate the operation amount θ b of the voltage phase.

[0076] The pulsation suppression unit 104 includes subtractors 201A and 201B, a rotation operation 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 rotation operation unit 202 may be arranged inside the pulsation extraction unit 103.

[0077] The target value r of the pulsation component stored in advance is input to the pulsation suppression 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. Usually, the target value r of the pulsation component * is set to zero, but the target value r of the pulsation component * may be set to a non-zero value (a value other than zero).

[0078] The subtractor 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 operation unit 202.

[0079] The subtractor 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 operation unit 202.

[0080] The rotation operation unit 202 performs a rotation operation on e cos and e sin using the following equation (4). Here, the cos component after the rotation operation is denoted as e Rcos , and the sin component after the rotation operation is denoted as e Rsin .

[0081]

Equation

[0082] θ in Equation (4) R is the rotation amount of the rotation operation. The rotation amount adjustment unit 205 determines the rotation amount θ R using the power factor angle φ. The rotation amount adjustment unit 205 outputs the rotation amount θ R to the rotation operation unit 202.

[0083] The rotation operation unit 202 receives the rotation amount θ R from the rotation amount adjustment unit 205. The rotation operation unit 202 performs a rotation operation on e R and e cos using the rotation amount θ sin received from the rotation amount adjustment unit 205.

[0084] 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 execute integral control by accumulating the error between the target value r * of the pulsation component and the actual value, and adding an amount proportional to this accumulated value to the operation amount θ b of the voltage phase.

[0085] 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 calculates the deviation e * which is the difference between the target value r cos of the pulsation component and the cos component y cossuch that e becomes zero, from e Rcos to x cos is determined. That is, the integral control unit 203A performs integral control so that y cos approaches the target value r of the pulsation component * and determines x cos .

[0086] Also, the integral control unit 203B performs integral control so that e Rsin , which is the rotated sin component, becomes zero. That is, the integral control unit 203B calculates the deviation e * between the target value r of the pulsation component sin and the sin component y of the pulsation of the norm or weighted norm sin and determines x Rsin from e sin such that e becomes zero. That is, the integral control unit 203B performs integral control so that y sin approaches the target value r of the pulsation component * and determines x sin .

[0087] Here, although the pulsation suppression unit 104 uses the integral control units 203A and 203B, the pulsation suppression unit 104 may use other control units. For example, the pulsation suppression unit 104 may use a control unit that performs P (Proportional) control, a control unit that performs PI (Proportional-Integral) control, or a control unit that performs PID (Proportional-Integral-Differential) control.

[0088] The AC restoration unit 204 converts the output of the integral control into AC and determines the operation amount θ b of the voltage phase. That is, the AC restoration unit 204 calculates the operation amount θ cos of the voltage phase based on x sin , x dis , and f b .

[0089] Here, the operation amount θ bThe calculation formula will be described. First, the conversion result obtained by converting the disturbance frequency f dis to the angular frequency is defined as the disturbance angular frequency ω dis . ω dis and f dis are related by the following equation (5).

[0090]

Equation

[0091] Here, the integration result of integrating ω dis with respect to time t is represented by the symbol θ dis .

[0092]

Equation

[0093] 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 b of the voltage phase can be expressed, for example, by the following equation (7).

[0094]

Equation

[0095] In equation (7), x cos , x sin are the cosine component and sine component of the output signal of the beatless control, respectively. The AC restoration unit 204 calculates the operation amount θ cos , x sin , and f dis of the voltage phase by applying them to equations (5) to (7). By applying f b to equations (5) to (7), sine waves and cosine waves corresponding to f dis are derived, and the operation amount θ dis corresponding to f dis is derived. b

[0096] FIG. 9 is a diagram showing the configuration of the rotation amount adjustment unit included in the beatless control unit according to Embodiment 1. The rotation amount adjustment unit 205 according to Embodiment 1 includes a low-pass filter (LPF: Low Pass Filter) 308, a gain calculation unit 307, and an adder 309.

[0097] The low-pass filter 308 performs a low-pass filter operation on the power factor angle φ, which is an example of power factor information, to remove high-frequency components, and sends the power factor angle φ with the high-frequency components removed to the gain calculation unit 307. The gain calculation unit 307 multiplies the power factor angle φ sent from the low-pass filter 308 by a coefficient and sends it to the adder 309. The adder 309 adds a default value (for example, 90 degrees) stored in advance to the power factor angle φ sent from the gain calculation unit 307 to determine the rotation amount θ R The adder 309 outputs the rotation amount θ R to the rotation calculation unit 202. Thereby, the beatless control unit 18 can reflect the power factor information in the beatless control. Note that the default value may be a value determined for any reason. The default value is, for example, an empirical value (fixed value) estimated from past beatless control.

[0098] FIG. 10 is a diagram showing the operation pattern of the deviation vector when the beatless control unit according to Embodiment 1 executes beatless control when the rotation amount is in an optimal state. FIG. 11 is a diagram showing the operation pattern of the deviation vector when the beatless control unit according to Embodiment 1 executes beatless control when the rotation amount is in a state within the range of ±90 degrees from the optimal value. FIG. 12 is a diagram showing the operation pattern of the deviation vector when the beatless control unit according to Embodiment 1 executes beatless control when the rotation amount is in a state more than ±90 degrees away from the optimal value.

[0099] The rotation amount θ R When it is in a state within the range of ±90 degrees from the optimal value, it is the case where the absolute value of the difference between the rotation amount θ R and the optimal value is less than 90 degrees. The rotation amount θR When it is in a state where it is more than ±90 degrees away from the optimum value, the rotation amount θ R is a case where the absolute value of the difference from the optimum value is greater than 90 degrees.

[0100] The horizontal axis in FIGS. 10 to 12 is the cos component (e cos ), and the vertical axis is the sin component (e sin ). In FIGS. 10 to 12, the deviation vector locus Et, which is the operation pattern of the 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 .

[0101] The first operation pattern shown in FIG. 10 is when the rotation amount θ R is in an optimal state. When the beatless control unit 18 starts beatless control in this state, the deviation vector E composed of e cos and e sin approaches the origin at the shortest distance due to the action of integral control.

[0102] The second operation pattern shown in FIG. 11 is when the rotation amount θ R is within the range of less than ±90 degrees from the optimum value. When the beatless control unit 18 starts beatless control at this time, the deviation vector E approaches the origin while drawing a spiral.

[0103] The third operation pattern shown in FIG. 12 is the rotation amount θR when it is farther than ±90 degrees from the optimum 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.

[0104] A fourth operation pattern (not shown) is when the rotation amount θ R is in the worst state (180 degrees away from the optimum 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.

[0105] As described above, if an appropriate rotation amount θ R is given, the pulsation suppression unit 104 can control the deviation e cos and the deviation e sin to zero. However, if the rotation amount θ R is inappropriate, the deviation e cos and the deviation e sin will diverge. Therefore, the beatless control unit 18 according to Embodiment 1 corrects the rotation amount θ R using the power factor information. As a result, the drive device 4 can expand the stable operation range compared to the conventional beatless control that does not use the power factor information.

[0106] Normally, since the target value r * of the pulsation component is set to zero, if the deviation e cos , e sin becomes zero, the cos component y cos and the sin component y sin of the pulsation of the norm or weighted norm of the dq-axis current also become zero.

[0107] In addition, when the integral control units 203A and 203B are not arranged in the beatless control unit 18 (for example, when the beatless control unit 18 executes P control), the beatless control unit 18 cannot make the deviation e cos , e sin zero. However, even in this case, the operation amount θ bBy changing [it], the possibility of improving the effect of beatless control can be enhanced.

[0108] In Embodiment 1, the reason for aiming to minimize the pulsation of the norm or weighted norm 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 V DC is pulsating, pulsations occur in both the d-axis and q-axis currents. However, in order to suppress both the d-axis and q-axis current pulsations simultaneously, both the amplitude and phase of the voltage must be manipulated. This is obvious from the perspective of the control degrees of 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.

[0109] In this way, the control unit 400 minimizes the pulsation of an arbitrary norm or weighted norm by appropriately operating the phase of the voltage. However, when trying to determine (search for) the operation amount θ b of the optimal voltage phase using integral control, control divergence as described in FIG. 12 may occur. Therefore, the control unit 400 of Embodiment 1 determines the operation amount θ b of the optimal voltage phase taking into account the influence of the motor power factor.

[0110] As a result, the control unit 400 can accurately suppress the pulsation of the phase current due to beat vibration under various operating conditions. Note that the effect of 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.

[0111] FIG. 13 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 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).

[0112] Thereafter, the coordinate conversion unit 17 performs coordinate conversion calculation of 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 .

[0113] The rotor position calculation unit 14 calculates the rotor position (step S40). Thereby, 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 estimates the estimated magnetic pole position θ^ * dq , which is the position information of the rotor, and the estimated angular velocity ω^ dq from the dq-axis voltage command vector V e and the dq-axis current vector I e .

[0114] 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 calculates the dq-axis voltage command vector V * e from the dq-axis current vector I e so that the speed command ω dq and the estimated angular velocity ω^ * dq match.

[0115] The beatless control unit 18 executes a beatless control operation (step S60). As a result, the beatless control unit 18 determines the operation amount θ of the voltage phase b Specifically, the beatless control unit 18 extracts the component of the disturbance frequency f dq contained in the dq-axis current vector I dis and determines the operation amount θ of the voltage phase for reducing the extracted component b .

[0116] The coordinate conversion unit 16 performs coordinate conversion on the voltage command to 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 and the estimated magnetic pole position θ^ e to convert the dq-axis voltage command vector V eb * dq into the three-phase voltage command vector V * uvw DC .

[0117] The modulation unit 13 executes a modulation operation (step S80). Specifically, the modulation unit 13 determines a PWM signal based on the DC bus voltage V DC and the three-phase voltage command vector V * uvw and gives the PWM signal to the inverter 11.

[0118] Next, the operation of the beatless control unit 18 will be described. FIG. 14 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.

[0119] In the beatless control unit 18, the weight coefficient setting unit 102 sets the weight coefficients w1 and w2 stored in advance to the norm calculation unit 101 (step S110). The norm calculation unit 101 executes a norm operation (step S120). That is, the norm calculation unit 101 calculates the norm or weighted norm of the dq-axis current vector I dq .

[0120] The pulsation extraction unit 103 performs a pulsation extraction operation on the norm or weighted norm calculated by the norm calculation unit 101 (step S130). That is, the pulsation extraction unit 103 extracts the pulsation component included in the norm or weighted norm based on the component of the disturbance frequency f dis and the harmonic component that is an integer multiple of the disturbance frequency f dis . The pulsation extraction unit 103 outputs the sin component and cos component of the pulsation of the norm to the pulsation suppression unit 104 as y sin and y cos , respectively.

[0121] The power factor information calculation unit 107 calculates power factor information (step S140). Specifically, the power factor information calculation unit 107 calculates power factor information from the dq-axis voltage command vector V * dq and the dq-axis current vector I dq . The pulsation suppression unit 104 performs a pulsation suppression operation (step S150). That is, the pulsation suppression unit 104 determines (automatically searches) the operation amount θ b of the voltage phase to reduce the pulsation component.

[0122] Next, the operation of the pulsation suppression unit 104 will be described. FIG. 15 is a flowchart showing the processing procedure of the pulsation suppression process executed by the pulsation suppression unit of the drive device according to Embodiment 1. The pulsation suppression unit 104 determines the point at which the pulsation of the norm or weighted norm is minimized in the following procedure.

[0123] 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 adjusts the rotation amount θ R based on the power factor information (step S220). The rotation amount adjustment unit 205 sets the adjusted rotation amount θ R to the rotation calculation unit 202.

[0124] The rotation calculation unit 202 performs a rotation operation of the vector using the rotation amount θ R (step S230). Specifically, the rotation calculation unit 202 uses ecos and e sin and the rotation amount θ R By applying to Equation (4), e which is the cos component after the rotation operation Rcos and e which is the sin component after the rotation operation Rsin are calculated.

[0125] The integral control units 203A and 203B execute integral control calculations (step S240). Specifically, the integral control unit 203A integrates e Rcos after the rotation operation to determine x which is the cos component of the output signal of the beatless control cos and the integral control unit 203B integrates e Rsin after the rotation operation to determine x which is the sin component of the output signal of the beatless control sin is determined.

[0126] The AC restoration unit 204 executes an AC restoration calculation (step S250). Specifically, the AC restoration unit 204 applies x cos , x sin , and f dis to Equations (5) to (7) to calculate the operation amount θ b of the voltage phase. The drive device 4 drives the AC motor 1 using the operation amount θ b of the voltage phase, so that even if the operating conditions change greatly, it is possible to effectively suppress the beat vibration of the current.

[0127] Next, the hardware configuration of the control unit 400 provided in the drive device 4 will be described. FIG. 16 is a diagram showing an example of the hardware configuration for realizing the control unit provided in the drive device according to Embodiment 1.

[0128] The control unit 400 is realized by a processor 91, a memory 92, and peripheral devices 93. Note that in not only Embodiment 1 but also other embodiments, the control unit 400 is realized by a processor 91, a memory 92, and peripheral devices 93.

[0129] 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 processes of steps S10 to S80 in FIG. 13.

[0130] The processor 91 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, also referred to as DSP (Digital Signal Processor)), or a system LSI (Large Scale Integration).

[0131] 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). Also, the memory 92 is not limited to these, and may be a magnetic disk, optical disk, compact disk, mini disk, or DVD (Digital Versatile Disc).

[0132] 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.

[0133] 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 example, for detecting the DC bus voltage V DC and the phase current of the AC motor 1, etc.

[0134] 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 example, for acquiring rotor position information.

[0135] Thus, according to Embodiment 1, the control unit 400 of the drive device 4 calculates the operation amount θ of the voltage phase so as to minimize the pulsation component based on the power factor information, so that 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 under various operating conditions. Thereby, the control unit 400 can effectively suppress the beat vibration caused by the pulsation of the DC bus voltage V b without performing complicated control adjustment. DC

[0136] In addition, since the control unit 400 can effectively suppress the beat vibration, it is possible to reduce the size and capacitance of the DC reactor 8 and the capacitor 9. Thereby, the manufacturing cost of the drive device 4 can be reduced and the energy saving performance can be improved.

[0137] In addition, the control unit 400 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, an increase in vibration and noise of the AC motor 1, etc. by suppressing the beat vibration.

[0138] In addition, the control unit 400 calculates the operation amount θ of the voltage phase so as to minimize the extracted pulsation component, and this operation amount θ b bSince the inverter 11 is controlled using this, it is possible to easily stabilize the current pulsation reduction effect regardless of the operating conditions of the drive device 4 and the installation conditions of the drive device 4. Therefore, the control unit 400 can effectively suppress the beat vibration of the current even if the operating conditions and installation conditions of the drive device 4 change significantly.

[0139] Embodiment 2. Next, Embodiment 2 will be described with reference to FIGS. 17 to 24. The rotation amount θ R The optimum value of depends not only on the power factor information but also on the rotation speed of the AC motor 1, the power supply inductance 6, etc. Therefore, in Embodiment 2, together with the power factor information, various information other than the power factor information is also used to stabilize the beatless control.

[0140] FIG. 17 is a diagram showing the configuration of the pulsation suppression unit included in the beatless control unit according to Embodiment 2. Among the components in FIG. 17, the components that achieve the same function as the pulsation suppression unit 104 of Embodiment 1 shown in FIG. 8 are given the same reference numerals, and duplicate explanations are omitted.

[0141] The beatless control unit 18 of Embodiment 2 has a pulsation suppression unit 104A instead of the pulsation suppression unit 104 compared to the beatless control unit 18 of Embodiment 1. The pulsation suppression unit 104A of Embodiment 2 has a rotation amount adjustment unit 206 instead of the rotation amount adjustment unit 205 compared to the pulsation suppression unit 104 of Embodiment 1.

[0142] The deviation e cos from the subtractor 201A and the deviation e sin from the subtractor 201B are input to the rotation amount adjustment unit 206. Different from the pulsation suppression unit 104 of Embodiment 1, the pulsation suppression unit 104A of Embodiment 2 uses the rotation amount adjustment unit 206 to correct the rotation amount θ cos using the deviation e sin of the cos component and the deviation e R of the sin component.

[0143] FIG. 18 is a diagram showing an operation pattern of a deviation vector when the beatless control unit according to Embodiment 2 executes beatless control. The horizontal axis in FIG. 18 is the cos component (e cos ), and the vertical axis is the sin component (e sin ). In FIG. 18, 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 as a deviation vector locus Et. The deviation vector locus Et has "Start" as the starting point and "Goal" as the ending point.

[0144] In the drive device 4 of Embodiment 2, when y cos which is the cos component of the pulsation of the norm or weighted norm of the dq-axis current or y sin which is the sin component increases unintentionally, this increase is detected. When the rotation amount adjustment unit 206 detects an unintentional 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 corrects the rotation amount θ R . The rotation amount adjustment unit 206 discovers a search direction for decreasing y cos and y sin by this correction operation, and finally makes the deviation vector E zero. Thereby, the drive device 4 can surely suppress beat vibration under any operating conditions.

[0145] Here, the concept of the search direction corrected by the beatless control unit 18 will be described. FIG. 19 is a first explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 2. FIG. 20 is a second explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 2. FIG. 21 is a third explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 2. FIG. 22 is a fourth explanatory diagram for explaining the search direction corrected by the beatless control unit according to Embodiment 2.

[0146] Figures 19 to 22 show the image of the search direction corrected by the beatless control unit 18. The horizontal axis in Figures 19 to 22 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 Figures 19 to 21, with respect to Figures 10 to 12, a deviation vector locus ERt which is an operation pattern (locus) of a deviation vector ER (not shown) after the rotation operation, an output signal locus xt which is an operation pattern of an output signal vector x (not shown), and a sector region representing the 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.

[0147] 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.

[0148] In Figures 19 to 22, the image of the search direction is shown as a fan-shaped figure (sector region) imitating the human visual field. Assuming that the center of the sector region is the position of the output signal vector x at a certain time, the arc portion of the sector region is the image of the forward visual field at that time.

[0149] Specifically, in Figure 19, the image of the search direction is shown as the search direction image SD1, and in Figure 20, the images of the search direction are shown as the search direction images SD2 and SD3. In Figure 21, the images of the search direction are shown as the search direction images SD4, SD5, and SD6, and in Figure 22, the images of the search direction are shown as the search direction images SD7 and SD8.

[0150] The search direction image SD1 shown in FIG. 19 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.

[0151] The search direction images SD2 and SD3 shown in FIG. 20 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.

[0152] The search direction images SD4, SD5, and SD6 shown in FIG. 21 are the search direction images when the rotation amount θ R is an inappropriate value. 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.

[0153] In FIGS. 19 to 21, the deviation vector trajectory Et is illustrated as the trajectory when the deviation vector E before the rotation operation tries 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).

[0154] Also, in FIGS. 19 to 21, the deviation vector trajectory ERt is illustrated as the trajectory when the deviation vector ER after the rotation operation tries 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).

[0155] Also, in Fig. 22, as shown in Fig. 21, the rotation amount θ R is inappropriate and the search fails. After the rotation amount θ R is adjusted, the trajectory when trying to go from the point of the initial value ERs of the deviation vector ER to the point (origin) of the ideal value Ei of the deviation vector ER is illustrated as the deviation vector trajectory ERt2.

[0156] 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 18 cannot know in advance where the ideal value of the output signal vector x is in the figure.

[0157] The beatless control unit 18 can only determine whether the search for the ideal value of the output signal vector x has been successful 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 a searchable range. 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 18 searches for the output signal vector x that minimizes the deviation vectors E and ER within the searchable range SR.

[0158] 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. 19 to 21, the initial value of the deviation vector E is indicated by the initial value Es, and the initial value of the deviation vector ER is indicated by 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.

[0159] In Fig. 19, the beatless control unit 18 according to Embodiment 2 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 R is in the optimal state.

[0160] 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 the rotation operation, have a phase difference of the rotation amount θ R When the rotation amount θ R is in an ideal state, the deviation vectors E and ER move from the initial values Es and ERs to 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 to the ideal value xi, which is the ideal point of the output signal vector x, along the shortest distance.

[0161] 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 along the shortest distance. In this case, since the parameter for adjusting the direction of the deviation vector ER is the rotation amount θ R the beatless control unit 18 can move the deviation vectors E and ER along the shortest distance toward the ideal value Ei by optimizing the rotation amount θ R

[0162] Since the output signal vector x moves along the direction of the deviation vector ER as seen from the origin, the direction of the deviation vector ER as 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.

[0163] The sector area (search direction image SD1) shown in FIG. 19 corresponds to the view 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.

[0164] The sector areas (search direction images SD2 and SD3) shown in FIG. 20 are for the rotation amount θ R ​corresponds to the visual field when it is within the range of ±90 degrees from the optimum 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 in the beatless control unit 18 (the integral control by the integral control units 203A and 203B), the beatless control unit 18 can finally reach the ideal value Ei for the deviation vectors E and ER. However, to the extent that the output signal vector x does not head towards the ideal value xi of the output signal vector x at the shortest distance, the deviation vectors E and ER will decrease in a spiral shape.

[0165] The sector regions (search direction images SD4, SD5, SD6) shown in FIG. 21 are for the rotation amount θ R corresponds to the visual field 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 beatless control unit 18 changes the output signal vector x, the search direction is not uniquely determined, and the output signal vector x is manipulated so that the deviation vectors E and ER head towards points different from the ideal value Ei. For this reason, the beatless control unit 18 increases the deviation vectors E and ER in a trajectory where the deviation vectors E and ER form a spiral, and the beatless control fails.

[0166] In FIG. 21, 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. 21, the point of the output signal vector x when it is detected that the search has failed is indicated by the arrival value xf.

[0167] In the second embodiment, in preparation for the case where the deviation vectors E and ER perform the operation as shown in FIG. 21, the beatless control unit 18 is provided with a search failure detection unit 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. 21 is that the search direction was inappropriate (in other words, the rotation amount θ Ris inappropriate). The beatless control unit 18 can succeed in searching for the optimal value of the rotation amount θ by detecting the failure of the search and correcting the search direction when the search fails. R The optimal value can be found.

[0168] In FIG. 22, an operation image is shown when the search direction is corrected and the search is executed again after the search for the optimal value of the rotation amount θ R has failed. That is, the behavior shown in FIG. 22 is the behavior when the beatless control unit 18 adjusts the rotation amount θ R and resets the rotation amount θ R to an appropriate value when it is detected that the search has failed. Note that, as in FIG. 21, in FIG. 22, 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.

[0169] In FIG. 22, the rotation amount before correction is indicated by the rotation amount Bθ R and the rotation amount after correction is indicated by the rotation amount Aθ R . Also, in FIG. 22, for the search direction image SD7 when it is detected that the search has failed, the search direction image after the beatless control unit 18 adjusts the rotation amount Bθ R is indicated by the search direction image SD8. When the beatless control unit 18 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 calculation change.

[0170] In FIG. 22, 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. 22, the locus of the deviation vector ER rotationally calculated by the adjusted rotation amount Aθ R is indicated by the deviation vector locus ERt2. Also, in FIG. 22, the locus of the deviation vector E rotationally calculated by the adjusted rotation amount Aθ R is indicated by the deviation vector locus Et2.

[0171] Suppose that by adjusting the rotation amount Bθ R the rotation amount AθR When it reaches the optimum value, since the ideal value xi of the output signal vector x lies on the extension of the search direction, the search for the optimum value is completed smoothly.

[0172] In addition, in Fig. 22, for convenience of explanation, the rotation amount θ R is adjusted by one adjustment of the rotation amount θ R has been described for the case where can be adjusted to the optimum value, but in reality, since the optimum 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.

[0173] Also, the beatless control unit 18 may continuously correct the rotation amount θ R during the operation of the beatless control by a method combining the outer product operation and PID control described later. By such a correction process of the rotation amount θ R , the deviation vector E may approach the origin through a complex deviation vector locus Et as shown in Fig. 18. Also, as shown in Fig. 22, after the correction of the rotation amount θ R , the deviation vector E may head towards the origin along a linear deviation vector locus Et2.

[0174] 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, the beat vibration will increase. Therefore, the search for the ideal value xi of the output signal vector x needs to be performed carefully. For this reason, in Embodiment 2, the beatless control unit 18 appropriately corrects the search direction of the beatless control so that the output signal vector x can surely reach the ideal value xi.

[0175] The rotation amount adjustment unit 206 may adjust the rotation amount θ R by any method. The rotation amount adjustment unit 206 may, for example, adjust the rotation amount θ RModify (adjust). Further, the rotation amount adjustment unit 206 may automatically search for the rotation amount θ using AI (Artificial Intelligence) or machine learning. R

[0176] Here, an example of the adjustment method of the rotation amount θ R will be described. FIG. 23 is a diagram showing the first behavior of the deviation vector when the beatless control unit according to Embodiment 2 executes beatless control. FIG. 24 is a diagram showing the second behavior of the deviation vector when the beatless control unit according to Embodiment 2 executes beatless control. FIG. 25 is a diagram showing the third behavior of the deviation vector when the beatless control unit according to Embodiment 2 executes beatless control.

[0177] The horizontal axis in FIGS. 23 to 25 is the cos component (e cos ), and the vertical axis is the sin component (e sin ). In FIGS. 23 to 25, the behavior of the deviation vector E composed of e cos and e sin when the pulsation suppression unit 104A executes beatless control is schematically shown.

[0178] The pulsation suppression unit 104A can determine whether the beatless control is being properly 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.

[0179] When the deviation vector E and the time differential vector (d / dt)E are in opposite phases as in the first behavior of the deviation vector E shown in FIG. 23, the pulsation suppression unit 104A determines that the beatless control is being performed well.

[0180] Also, when the direction of the time differential vector (d / dt)E is inside (the origin side) with respect to the perpendicular line of the deviation vector E as in the second behavior of the deviation vector E shown in FIG. 24, the pulsation suppression unit 104A determines that the beatless control is being performed appropriately to some extent.​

[0181] When the direction of the time derivative vector (d / dt)E is outside the perpendicular line of the deviation vector E as in the third behavior of the deviation vector E shown in FIG. 25, the pulsation suppression unit 104A determines that the beatless control is not being properly performed.

[0182] If the state of the deviation vector E shown in FIG. 25 is left unchanged, the beatless control becomes unstable and diverges. Therefore, the pulsation suppression unit 104A adjusts the rotation amount θ so that the deviation vector E reaches the state shown in FIG. 23 or FIG. 24. R to correct it.

[0183] In addition, as shown in FIG. 24, when the direction of the time derivative vector (d / dt)E is inside the perpendicular line of the deviation vector E, the pulsation suppression unit 104A may adjust the rotation amount θ so that the direction of the time derivative vector (d / dt)E further turns inward. R to correct it.

[0184] The pulsation suppression unit 104A evaluates whether the beatless control is being properly performed using a quantitative numerical value (evaluation value) in order to correct the rotation amount θ. The pulsation suppression unit 104A corrects the rotation amount θ with a correction amount corresponding to the evaluation value. R to correct it. R to correct it.

[0185] FIG. 26 is a diagram for explaining an evaluation value for evaluating whether the beatless control is being properly performed by the pulsation suppression unit according to Embodiment 2. The horizontal axis in FIG. 26 is the cos component, and the vertical axis is the sin component.

[0186] FIG. 26 shows an example of the definition of the evaluation value. The pulsation suppression unit 104A evaluates the validity of the operation of the beatless control by using, for example, the cross product of the deviation vector E and the time derivative vector (d / dt)E of the deviation vector E (the area of the parallelogram formed by the two vectors). Here, the evaluation value for evaluating whether the beatless control is being properly performed is denoted by C. d is shown. The cross product of the deviation vector E and the time derivative vector (d / dt)E of the deviation vector E is C. dIt is as follows.

[0187] The pulsation suppression 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. Thus, 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 pulsation suppression 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

[0188] FIG. 27 is a diagram showing the configuration of the rotation amount adjustment unit included in the pulsation suppression unit according to Embodiment 2. The rotation amount adjustment unit 206 of Embodiment 2 includes an outer product calculation unit 300, a dead zone 305, a PID control unit 306, a gain calculation unit 307, a low-pass filter 308, and an adder 309.

[0189] The outer product calculation unit 300 includes pseudo differentiators 302A and 302B, multipliers 303A and 303B, and a subtractor 304. The power factor angle φ is input from the power factor information calculation unit 107 to the rotation amount adjustment unit 206.

[0190] Note that the symbol s shown in FIG. 27 is a Laplace operator. For the rotation amount adjustment unit 206, a differentiator without a low-pass filter (LPF) may be used instead of the pseudo differentiators 302A and 302B, but in FIG. 27, the case where the pseudo differentiators 302A and 302B provided with low-pass filters for removing differential noise are used will be described.

[0191] The deviation e cos is input to the outer product calculation unit 300 from the subtractor 201A, and the deviation e sin is input from the subtractor 201B.

[0192] The outer product calculation unit 300 calculates C d which is an evaluation value by the above-described outer product calculation. In the outer product calculation unit 300, the deviation e​cos is input to the pseudo differentiator 302A and the multiplier 303B, and the deviation e sin is input to the pseudo differentiator 302B and the multiplier 303A.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] The dead zone 305 stops the adjustment of the rotation amount θ R after the beatless control converges to the final value. Since it is not preferable in terms of the stability of the beatless control that the adjustment of the rotation amount θ R is performed more than necessary, the rotation amount adjustment unit 206 of Embodiment 3 stops the adjustment of the rotation amount θ R by the dead zone 305 after the beatless control converges to the final value. Note that the rotation amount adjustment unit 206 using the dead zone 305 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

[0197] ​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 adder 309. 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 performs 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.

[0198] The low-pass filter 308 performs a low-pass filter operation on the power factor angle φ input to the rotation amount adjustment unit 206 to remove high-frequency components, and sends the power factor angle φ with the high-frequency components removed to the gain calculation unit 307. The gain calculation unit 307 multiplies the power factor angle φ sent from the low-pass filter 308 by a coefficient and sends it to the adder 309. The adder 309 adds the rotation amount θ R sent from the PID control unit 306, the power factor angle φ sent from the gain calculation unit 307, and a default value (for example, 90 degrees) stored in advance to correct the rotation amount θ R . The adder 309 outputs the rotation amount θ R , which is the addition result, to the rotation calculation unit 202.

[0199] In this way, the rotation amount adjustment unit 206 of the second embodiment determines the rotation amount θ R by the sum of the default value, the output from the PID control unit 306, and the power factor angle φ which is power factor information.

[0200] 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 in any case.

[0201] Next, the operation of the rotation amount adjustment unit 206 will be described. FIG. 28 is a flowchart showing the processing procedure of the rotation amount adjustment process executed by the rotation amount adjustment unit according to the second embodiment.

[0202] The outer product calculation unit 300 calculates C, which is an evaluation value for determining whether the beatless control is appropriately performed, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the evaluation value C based on the deviation e of the cosine component calculated by the subtractor 201A and the deviation e calculated by the subtractor 201B. d The outer product calculation unit 300 calculates C, which is an evaluation value for determining whether the beatless control is appropriately performed, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the evaluation value C based on the deviation e of the cosine component calculated by the subtractor 201A and the deviation e calculated by the subtractor 201B. cos The outer product calculation unit 300 calculates C, which is an evaluation value for determining whether the beatless control is appropriately performed, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the evaluation value C based on the deviation e of the cosine component calculated by the subtractor 201A and the deviation e calculated by the subtractor 201B. sin The outer product calculation unit 300 calculates C, which is an evaluation value for determining whether the beatless control is appropriately performed, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the evaluation value C based on the deviation e of the cosine component calculated by the subtractor 201A and the deviation e calculated by the subtractor 201B. d The outer product calculation unit 300 calculates C, which is an evaluation value for determining whether the beatless control is appropriately performed, by outer product calculation (step S320). That is, the outer product calculation unit 300 calculates the evaluation value C based on the deviation e of the cosine component calculated by the subtractor 201A and the deviation e calculated by the subtractor 201B.

[0203] 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 corrects the rotation amount θ so that the evaluation value C becomes zero. d 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 corrects the rotation amount θ so that the evaluation value C becomes zero. R 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 corrects the rotation amount θ so that the evaluation value C becomes zero.

[0204] The low-pass filter 308 executes a low-pass filter operation on the power factor angle φ input to the rotation amount adjustment unit 206 (step S350). Specifically, the low-pass filter 308 removes high-frequency components and sends the power factor angle φ from which the high-frequency components have been removed to the gain calculation unit 307.

[0205] The gain calculation unit 307 executes gain calculation (step S360). Specifically, the gain calculation unit 307 multiplies the power factor angle φ sent from the low-pass filter 308 by a coefficient to determine the rotation amount θ and sends it to the adder 309. R The gain calculation unit 307 executes gain calculation (step S360). Specifically, the gain calculation unit 307 multiplies the power factor angle φ sent from the low-pass filter 308 by a coefficient to determine the rotation amount θ and sends it to the adder 309.

[0206] The adder 309 executes an addition process (step S370). Specifically, the adder 309 adjusts the rotation amount θ by adding the power factor angle φ sent from the gain calculation unit 307 and a default value (for example, 90 degrees) to the rotation amount θ sent from the PID control unit 306. R The adder 309 executes an addition process (step S370). Specifically, the adder 309 adjusts the rotation amount θ by adding the power factor angle φ sent from the gain calculation unit 307 and a default value (for example, 90 degrees) to the rotation amount θ sent from the PID control unit 306. R The adder 309 executes an addition process (step S370). Specifically, the adder 309 adjusts the rotation amount θ by adding the power factor angle φ sent from the gain calculation unit 307 and a default value (for example, 90 degrees) to the rotation amount θ sent from the PID control unit 306.

[0207] Thus, according to Embodiment 2, the control unit 400 of the drive device 4 automatically detects an inappropriate state when the rotation amount θ R is in an inappropriate state, and corrects the rotation amount θ R . Therefore, it is possible to effectively suppress the beat vibration caused by the pulsation of the DC bus voltage V dc without performing complicated control adjustment.

[0208] Further, according to Embodiment 2, when the drive device 4 detects an unintended increase in y cos and y sin , it corrects the rotation amount θ R . Therefore, it is possible to surely suppress the beat vibration under various operating conditions.

[0209] Embodiment 3. Next, Embodiment 3 will be described with reference to FIG. 29. In Embodiment 3, the drive device 4 described in Embodiments 1 and 2 is applied to a refrigeration cycle device.

[0210] FIG. 29 is a diagram showing the configuration of a refrigeration cycle device according to Embodiment 3. Among the components in FIG. 29, the components that achieve the same functions as the drive device 4 and the compressor 3 of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0211] The refrigeration cycle device 900 according to Embodiment 3 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.

[0212] The refrigeration cycle device 900, which is a device to which a refrigeration cycle is applied, 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, a compressor 3, a drive device 4, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910 are connected via a refrigerant pipe 912.

[0213] Inside the compressor 3, a compression mechanism 904 for compressing the refrigerant and an alternating current motor 1 for operating the compression mechanism 904 are provided. The compression mechanism 904 corresponds to the mechanical device 2 described in the first embodiment. 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 alternating current motor 1 that is variably speed-controlled.

[0214] During the heating operation, as shown by the solid-line arrow, the refrigerant is pressurized and sent out by the compression mechanism 904, passes through the four-way valve 902, the indoor heat exchanger 906, the expansion valve 908, the outdoor heat exchanger 910, and the four-way valve 902, and returns to the compression mechanism 904.

[0215] During the cooling operation, as shown by the dashed-line arrow, the refrigerant is pressurized and sent out by the compression mechanism 904, passes through the four-way valve 902, the outdoor heat exchanger 910, the expansion valve 908, the indoor heat exchanger 906, and the four-way valve 902, and returns to the compression mechanism 904.

[0216] 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, and the indoor heat exchanger 906 acts as an evaporator to absorb heat. The expansion valve 908 decompresses and expands the refrigerant.

[0217] Thus, according to Embodiment 3, 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, an increase in vibration and noise of the AC motor 1, etc. by suppressing the beat vibration.

[0218] 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 capacitance. Thereby, the manufacturing cost of the refrigeration cycle device 900 can be reduced and the energy saving performance can be improved.

[0219] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine the embodiments with each other, or omit or change a part of the configuration without departing from the gist.

Description of Reference Numerals

[0220] 1 AC motor, 2 mechanical device, 3 compressor, 4 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 beatless control unit, 19, 309 adder, 91 processor, 92 memory, 93 peripheral device, 101 norm calculation unit, 102 weight coefficient setting unit, 103 pulsation extraction unit, 104, 104A pulsation suppression unit, 107 power factor information calculation unit, 201A, 201B, 304, 402 subtractor, 202 rotation calculation unit, 203A, 203B integral control unit, 204 AC restoration unit, 205 rotation amount adjustment unit, 206 rotation amount adjustment unit, 300 outer product calculation unit, 302A, 302B pseudo differentiator, 303A, 303B multiplier, 305 dead zone, 306 PID control unit, 307 gain calculation unit, 308 low pass filter, 400 control unit, 401A, 401B angle calculation 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 The system includes a power factor information calculation unit that calculates power factor information, which is the power factor information of the AC motor, and operates the voltage phase based on the power factor information and the pulsating component of the norm of the current vector. A drive device characterized by the following features.

2. The aforementioned beatless control unit is A norm calculation unit that calculates the aforementioned norm, A pulsation extraction unit for extracting the pulsation component of the norm, A pulsation suppression unit that determines the amount of voltage phase manipulation that reduces the pulsation component using the power factor information, It has, The beatless control unit manipulates the voltage phase using the manipulated amount. The drive device according to feature 1.

3. The pulsation extraction unit separates and extracts the pulsation component of the norm into a cosine component and a sine component. The pulsation suppression unit is, A rotation amount adjustment unit that determines the amount of rotation when performing rotation calculations on the cosine component and the sine component using the power factor information, A rotation calculation unit that performs rotation calculations on the cosine component and the sine component using the rotation amount, 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, The drive device according to feature 2.

4. The rotation amount adjustment unit is, When an increase in the cosine component and the sine component is detected, the amount of rotation is corrected. The drive device according to feature 3.

5. 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.

6. 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 2.

7. The aforementioned beatless control unit is The power factor angle, which is the phase difference between the axis voltage command vector and the axis current vector of the rotating two-phase coordinate system, is calculated as the power factor information. The drive device according to feature 6.

8. A drive device according to any one of claims 1 to 7, A compressor driven by the aforementioned AC motor, Equipped with, A compressor drive system characterized by the following features.

9. The compressor drive system is provided according to claim 8. A refrigeration cycle device characterized by the following features.

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