JP6489171B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device.

  For example, in a compressor used in a refrigeration cycle such as an air conditioner, it is known that a change in refrigerant gas pressure in each stroke of suction, compression, and discharge acts on a load torque. Since the shaft of the electric motor is directly connected to the compressor, the rotor pulsates due to a periodic load torque variation caused by a change in refrigerant pressure synchronized with the shaft rotation of the electric motor, and a rotational speed variation of the rotor occurs. Such periodic fluctuations in the rotational speed of the rotor synchronized with the shaft rotation of the motor may cause vibration and noise, and may cause damage to the piping of the refrigeration cycle. The operation at will be severely limited.

  Conventionally, as such a compressor damping control, an open loop type in which a fluctuation pattern of load torque is tabulated and the output torque of the motor is changed according to the rotation angle of the rotor of the motor to cancel the vibration. The control method is the mainstream. In such an open loop type vibration damping control method, it is necessary to create a load torque variation pattern corresponding to the load and the rotational speed, and development takes a lot of time. Further, when the operating conditions change, the optimum operation is not always performed with the load torque fluctuation pattern created in advance, and the optimum vibration damping effect may not be obtained depending on the state.

  Non-Patent Document 1, for example, discloses a configuration in which a pulsation torque component is estimated from an axial error and a pulsation torque suppression current command value is calculated so that the pulsation torque component becomes zero. Specifically, first, a periodic torque pulsation component is estimated from periodic fluctuations of the estimated coordinate axis, the torque pulsation component thus estimated is subjected to Fourier transform, and the torque current is obtained by performing Fourier inverse transform through an integral compensator. Create a command value. Thereby, according to the nonpatent literature 1, it is supposed that a periodic torque fluctuation can be suppressed, without producing a torque pattern in advance.

Yasuo Notohara and four others, “Examination of periodic torque disturbance suppression control”, 2004 IEEJ Industrial Application Conference, September 14, 2004, 1-57 (I-337 to I-340)

  However, since the technique described in Non-Patent Document 1 requires Fourier transform and inverse Fourier transform, the processing is complicated and requires many filters and memories.

The technology disclosed, which has been made in view of the above, without requiring a great deal of development effort, a more simple control, to suppress the rotational speed variation caused by cyclic loading pulsations, reduces vibration and noise The purpose is to do.

A motor control device according to an embodiment of the present disclosure relates to a motor that performs vector control of the electric motor by decomposing the current flowing through the electric motor into a q-axis current and a d-axis current in an electric motor that drives a load whose load torque fluctuates periodically. A control device, a speed controller that generates a current command value according to a speed difference that is a difference between an angular velocity command and an angular velocity, and a q-axis that is a difference between a q-axis current command value and a q-axis current detection value A q-axis current controller that generates a q-axis voltage command value according to the current difference, and a d-axis voltage command value according to a d-axis current difference that is a difference between the d-axis current command value and the d-axis current detection value. and d-axis current controller which generates a q-axis current correction value calculation processing unit for generating a q-axis current correction value for correcting the q-axis current command value, Ru comprising a.

According to the aspect of the disclosure, it is possible to suppress fluctuations in rotational speed due to periodic load pulsation and to reduce vibration and noise without requiring a great deal of development man-hours and with simpler control.

FIG. 1 is a diagram illustrating a configuration example of a motor control device according to the first embodiment. FIG. 2 is a diagram illustrating the definition of coordinate axes. FIG. 3 is a diagram showing the definition of variable names. FIG. 4 is a block diagram showing the output torque generation block of the IPM motor and the relationship between the difference between the output torque and the load torque and the angular velocity. FIG. 5 is a diagram illustrating a first variation example of the load torque with respect to the rotation angle of the single rotary compressor. FIG. 6 is a diagram of a configuration example of the q-axis current correction value calculation processing unit of the motor control device according to the first embodiment. FIG. 7 is a block diagram in which q-axis current correction value calculation processing units are multiplexed. FIG. 8 is a diagram illustrating a second variation example of the load torque with respect to the rotation angle of the single rotary compressor. FIG. 9 is a diagram illustrating an example of a combined waveform of the fundamental wave component and the second harmonic component of the load torque fluctuation component. FIG. 10 is a diagram of a configuration example of the motor control device according to the third embodiment. FIG. 11 is a diagram of a configuration example of the d-axis current correction value calculation processing unit of the motor control device according to the third embodiment. FIG. 12 is a block diagram in which d-axis current correction value calculation processing units are multiplexed. FIG. 13 is a diagram illustrating an example of a damping characteristic when the fundamental wave component and the second harmonic component are controlled, and q-axis current correction and d-axis current correction are performed.

  Embodiments of a motor control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
A schematic configuration of the motor control device 1 according to the first embodiment will be described with reference to FIGS. FIG. 1 is a diagram illustrating a configuration example of a motor control device according to the first embodiment. FIG. 2 is a diagram illustrating the definition of coordinate axes. FIG. 3 is a diagram showing the definition of variable names.

  In the coordinate axes used in the following description, as shown in FIG. 2, the d axis is the magnetic flux axis of the rotor (the N pole side is the + direction), the q axis is the axis orthogonal to the d axis, and θe is the electrical angle. It is assumed that the estimated position of the rotor (estimated angle with respect to the U axis) is represented, and ωe is the estimated angular velocity of the rotor expressed in electrical angle. In addition, the z axis is a virtual axis that is orthogonal to both the d axis and the q axis. Further, main variable names used in the following description are shown in FIG.

  As shown in FIG. 1, the motor control device 1 according to the first embodiment includes a drive unit 10, a current detection unit 50, a phase / angular velocity detection unit 20, and a voltage command generation unit 30.

  A winding of each phase of the U, V, and W phases is wound around the motor M, and an AC voltage is applied to the winding of each phase. The drive unit 10 drives the electric motor M by supplying an alternating voltage whose phase is shifted by 120 ° in electrical angle to the windings of each phase. The internal configuration of the drive unit 10 will be described later.

The current detection unit 50 detects (picks up) the amplitude of at least two-phase currents. Specifically, the current detection unit 50 includes a current sensor 51 and a current sensor 52. The current sensor 51 detects the amplitude of the U-phase current i _U and supplies it to the phase / angular velocity detector 20. The current sensor 52 detects the amplitude of the W-phase current i _W and supplies it to the phase / angular velocity detector 20. Each of the current sensor 51 and the current sensor 52 may AD-convert the current value and supply it to the phase / angular velocity detector 20 as a signal that can be controlled by a digital computer. The current detection unit 50 may be, for example, a CT or other current detection means such as using a shunt resistor.

  The phase / angular velocity detection unit 20 receives the detected U-phase current iu and W-phase current iw and the V-phase current iv calculated from iu and iw from the current detection unit 50, and receives a current vector (iu, iv, iw). ) To obtain the estimated position θe and the estimated angular velocity ωm.

  Specifically, the phase / angular velocity detection unit 20 includes a three-phase to two-phase converter (u, v, w / dq) 21, an axis error calculation processing unit 22, a PLL controller 23, and a converter 25. And an integrator 61.

  The three-phase to two-phase converter (u, v, w / dq) 21 receives the detected value of the amplitude of the U-phase current iu from the current sensor 51, and receives the detected value of the amplitude of the W-phase current iw as the current sensor 52. The V-phase current iv is calculated from the currents of the other phases and the estimated position θe is received from the integrator 61. For example, the current vector (iu, iv, iw) in the fixed coordinate system (UVW coordinate system) is rotated. Conversion into current vector (Id, Iq) in the system (dq coordinate system). The rotating coordinate system (dq coordinate system) has a d axis and a q axis that intersect each other.

  Since each component in the current vector (Id, Iq) is converted from the detected current vector (iu, iv, iw), it can be regarded as a detected value. Hereinafter, they are simply referred to as d-axis current Id and q-axis current Iq.

  The three-phase to two-phase converter 21 outputs the d-axis current Id and the q-axis current Iq to the voltage command generation unit 30 and the axis error calculation processing unit 22.

  The axis error calculation processing unit 22 receives the d-axis current Id and the q-axis current Iq from the three-phase / two-phase converter 21, and receives the d-axis voltage command value Vd * and the q-axis voltage command value Vq * as a voltage command generation unit 30. In response to the d-axis current Id, the q-axis current Iq, the d-axis voltage command value Vd *, and the q-axis voltage command value Vq *, an axis error Δθ that is a deviation between the actual position of the rotor and the estimated position is calculated. Obtained and output to the PLL controller 23.

  In the following, the rotational position of the rotor is exemplarily described in the case of being estimated by the sensorless method. However, for example, in the case of receiving and recognizing the detection value by the sensor (encoder), the “estimated angular velocity” is set. If it is read as “actual angular velocity”, the following explanation can be applied as it is.

  The PLL controller 23 corrects the estimated angular velocity ωe estimated immediately before according to the axis error Δθ, and outputs it to the integrator 61 and the converter 25.

  The integrator 61 calculates the estimated position θe in the fixed coordinate system (UVW coordinate system) by integrating the estimated angular velocity ωe, and outputs the estimated position θe to the drive unit 10 and the voltage command generation unit 30, respectively.

  The converter 25 divides the estimated angular velocity ωe in the fixed coordinate system (UVW coordinate system) by the number of pole pairs Pn (Pn is the number of motor pole pairs) (multiply by the reciprocal 1 / Pn of the number of pole pairs) to express the mechanical angle. The estimated angular velocity ωm of the rotor thus obtained is obtained and output to the voltage command generator 30.

  The voltage command generation unit 30 receives the d-axis current Id, the q-axis current Iq, the estimated position θe, and the estimated angular velocity ωm from the phase / angular velocity detection unit 20, and receives the d-axis current command value Id0 * and the angular velocity command ωm * from the outside ( For example, a d-axis voltage command value Vd * and a q-axis voltage command are received according to a d-axis current Id, a q-axis current Iq, an estimated position θe, an estimated angular velocity ωm, and an angular velocity command ωm *. A value Vq * is generated and output to the drive unit 10 and the phase / angular velocity detection unit 20. The details of the voltage command generator 30 will be described later.

  The drive unit 10 receives the d-axis voltage command value Vd * and the q-axis voltage command value Vq * from the voltage command generation unit 30, receives the estimated position θe from the phase / angular velocity detection unit 20, and drives the motor M. The DC voltage Vdc is received from the outside (for example, a host controller not shown), and the three-phase AC voltage is determined according to the d-axis voltage command value Vd *, the q-axis voltage command value Vq *, the estimated position θe, and the DC voltage Vdc. Is supplied to the motor M through the windings of the U-phase, V-phase, and W-phase phases, thereby driving the motor M.

  Specifically, the drive unit 10 includes a two-phase to three-phase converter (dq / u, v, w) 11, a PWM modulator 12, and an intelligent power module (IPM) 13.

  The two-phase / three-phase converter (dq / u, v, w) 11 includes a d-axis voltage command value Vd * and a q-axis voltage command Vq *, that is, a voltage command in a rotating coordinate system (dq coordinate system). The vector (Vd *, Vq *) is received from the voltage command generator 30 and the estimated position θe is received from the integrator 61. For example, the voltage command vector in the rotating coordinate system (dq coordinate system) according to the estimated position θe. (Vd *, Vq *) is converted into voltage command vectors (Vu *, Vv *, Vw *) in a fixed coordinate system (UVW coordinate system).

  The PWM modulator 12 is a voltage command vector (Vu *, Vv *, Vw *) in a fixed coordinate system (UVW coordinate system), that is, a U-phase voltage command Vu *, a V-phase voltage command Vv *, and a W-phase voltage command Vw *. Is received from the two-phase to three-phase converter 11, the U-phase voltage command Vu *, the V-phase voltage command Vv *, and the W-phase voltage command Vw * are converted into PWM signals and supplied to the intelligent power module 13. Thereby, the PWM modulator 12 converts the voltage (DC voltage Vdc) supplied from the outside via the intelligent power module 13 into a three-phase AC voltage, and drives the motor M.

  The intelligent power module 13 includes, for example, a plurality of switching elements (not shown), receives a PWM signal from the PWM modulator 12, and performs a power conversion operation by switching the plurality of switching elements at a predetermined timing according to the PWM signal. By supplying the generated three-phase AC voltage to the electric motor M, the electric motor M is driven.

  The voltage command generation unit 30 includes a subtractor 32, a speed controller 33, a q-axis current correction value calculation processing unit 100, a subtractor 35, a subtractor 45, a d-axis current controller 36, a q-axis current controller 46, a non-interference A controller 41, a subtractor 37, an adder 47, and an adder 43.

  The subtractor 32 receives the angular velocity command ωm * from the outside, receives the estimated angular velocity ωm from the calculation unit 20, subtracts the estimated angular velocity ωm from the angular velocity command ωm *, and sets the subtraction result as the angular velocity difference Δωm as the speed controller 33 and the q axis. Output to the current correction value calculation processing unit 100.

  The speed controller 33 includes, for example, an integrator and a proportional device, and generates a q-axis current command value Iq0 * using the integrator and the proportional device in accordance with the angular velocity difference Δωm.

  The q-axis current correction value calculation processing unit 100 receives the angular velocity difference Δωm from the subtractor 32, receives the estimated position θe from the phase / angular velocity detection unit 20, and calculates the k-th harmonic component ΔIqk of the q-axis correction current ΔIq from the angular velocity difference Δωm. (Q-axis current correction value) is calculated and output to the adder 43. The detailed configuration and operation of the q-axis current correction value calculation processing unit 100 will be described later.

  The adder 43 receives the q-axis current command value Iq0 * from the speed controller 33, and receives the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq from the q-axis current correction value calculation processing unit 100. The q-axis current command value Iq0 * and the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq are added, and the addition result is used as the q-axis current command correction value Iq *. Output to.

  The subtractor 35 receives the d-axis current command value Id0 * from the outside, receives the d-axis current detection value Id from the position / speed detection unit 20, and subtracts the d-axis current detection value Id from the d-axis current command value Id0 *. The subtraction result is output to the d-axis current controller 36.

  The subtractor 45 receives the q-axis current command correction value Iq * from the adder 43, receives the q-axis current detection value Iq from the position / speed detection unit 20, and converts the q-axis current command correction value Iq * to the q-axis current detection value. Iq is subtracted, and the subtraction result is output to the q-axis current controller 46.

  The d-axis current controller 36 includes, for example, an integrator and a proportional device, and generates a d-axis voltage command value Vd ** using the integrator and the proportional device in accordance with the output from the subtractor 35.

  The q-axis current controller 46 includes, for example, an integrator and a proportional device, and generates a q-axis voltage command value Vq ** using the integrator and the proportional device in accordance with the output from the subtracter 45.

  The non-interacting controller 41 decouples the q-axis voltage command value Vq ** and the d-axis voltage command value Vd **. Specifically, the non-interacting controller 41 receives the d-axis current detection value Id from the phase / angular velocity detection unit 20, receives the estimated angular velocity ωe from the phase / angular velocity detection unit 20, and responds to the d-axis current detection value Id. Thus, the non-interacting correction value Vqa for deinteracting the q-axis voltage command value Vq ** is obtained, and the non-interacting correction value Vqa is output to the adder 47. Further, the non-interacting controller 41 receives the q-axis current detection value Iq from the phase / angular velocity detection unit 20, receives the estimated angular velocity ωe from the phase / angular velocity detection unit 20, and d according to the q-axis current detection value Iq. A non-interacting correction value Vda for decoupling the shaft voltage command value Vd ** is obtained, and the non-interacting correction value Vda is output to the subtractor 37.

  The subtractor 37 receives the d-axis voltage command value Vd ** from the d-axis current controller 36, receives the non-interacting correction value Vda from the non-interacting controller 41, and decouples from the d-axis voltage command value Vd **. Correction value Vda is subtracted, and the subtraction result is output to drive unit 10 and calculation unit 20 as d-axis voltage command value Vd * after decoupling.

  The adder 47 receives the q-axis voltage command value Vq ** from the q-axis current controller 46, receives the non-interacting correction value Vqa from the non-interacting controller 41, and does not interfere with the q-axis voltage command value Vq **. Correction value Vqa is added, and the addition result is output to drive unit 10 and calculation unit 20 as q-axis voltage command value Vq * after decoupling.

  Next, vibration suppression control according to the present embodiment will be described with reference to FIGS. 4 and 5.

  The electric motor M controlled by the motor control device 1 is, for example, an IPM (Interior Permanent Magnetic) motor, and a basic voltage-current equation of the IPM motor is expressed by the following equations (1) and (2).

  In the above formulas (1) and (2), p is a differential operator.

  Further, the output torque TM generated in the IPM motor at this time is expressed by the following equation (3).

  In the above equation (3), the term Pn × φe × Iq represents the magnet torque, and the term Pn × (Ld−Lq) × Id × Iq represents the reluctance torque. As expressed in the equation (3), the magnet torque is proportional to the q-axis current Iq, and the reluctance torque is proportional to the product of the q-axis current Iq and the d-axis current Id.

  FIG. 4 is a block diagram showing the output torque generation block of the IPM motor and the relationship between the difference between the output torque and the load torque and the angular velocity. S in FIG. 4 indicates a Laplace plane. Further, in FIG. 4, the description is made from the back of the interference voltage term of the IPM motor.

  From FIG. 4, the relationship between the difference between the output torque TM of the IPM motor and the load torque TL (hereinafter referred to as “pulsation torque”) and the angular velocity ωm is expressed by the following equation (4), where the constant J is the moment of inertia. The

  FIG. 5 is a diagram illustrating a first variation example of the load torque with respect to the rotation angle of the single rotary compressor.

  In the above equations (1) and (2), in the state where the IPM motor is operating at a constant speed when the load torque is low in the rotating coordinate system, all terms are DC values, but pulsating torque is generated. In this case, fluctuations in the rotational angular velocity occur.

  In the present embodiment, a current component that cancels out the pulsating torque is calculated from the variation in the rotational angular velocity and is superimposed on the q-axis current Iq, thereby suppressing the rotational velocity variation accompanying the periodic load torque variation.

  The fluctuation component of the load torque includes a harmonic component in addition to the fundamental wave component. In the first variation example shown in FIG. 5, assuming that the amplitude of the fundamental component of the variation component of the load torque is 100%, the amplitude ratio of the harmonic component is about 25% for the second harmonic component, The amplitude of the third harmonic component is about 8%.

  Although not shown, for example, in a twin rotary compressor, it is conceivable that the second harmonic component is included more than the fundamental wave component of the load torque fluctuation component. Therefore, in the case of a twin rotary compressor, suppressing the second harmonic component is more effective than the fundamental component. As described above, the harmonic component contained in the variation component of the load torque differs depending on the device to which the IPM motor is applied.

  Therefore, it is possible to obtain a high vibration damping effect by canceling out the harmonic component that is included more in the load torque fluctuation component.

  If the difference between the output torque TM output from the electric motor M and the load torque TL is ΔT, this ΔT is the pulsation torque that causes the pulsation of the rotor. The pulsation torque ΔT is expressed by the following equation (5).

  Since the pulsation torque ΔT varies periodically according to a specific position (rotation angle) with respect to the rotation angle θm, the spatial harmonic of the speed change of the rotor in the time domain associated with the variation is expressed by the following equation (6). Define.

  In the above equation (6), k represents the order of the harmonic component. Δωmk represents the k harmonic component of the fluctuation speed, ωmk represents the amplitude of the k harmonic component, θmk represents the rotation angle of the k harmonic component, and φk represents the phase term of the k harmonic component. When k = 1, the value in the fundamental wave of the pulsating torque is shown, when k = 2, the value in the second harmonic of the pulsating torque is shown, and when k = 3, the pulsating value is shown. The value at the third harmonic of the torque is shown. Further, when k = 0, it indicates a direct current value. The same applies to the following description.

  Since s in the equation (5) represents time differentiation, the pulsation torque ΔTk at a specific k-th harmonic can be expressed by the following equation (7).

  Here, when considering that the output torque is corrected by ΔTM so as to cancel the pulsation torque ΔT, the relationship between the corrected output torque (TM + ΔTM) and the load torque TL is expressed by the following equation (8).

Assuming that a specific k-th harmonic component is separated from the above equation (8), the following equation (9) is obtained.

  If the calculation result of equation (9) becomes 0, the k-th harmonic component ΔTk of the pulsating torque ΔT is canceled by the k-th harmonic component ΔTMk of the correction torque component ΔTM of the output torque. At this time, the conversion formula of the q-axis current correction value ΔIqk that generates the k-th harmonic component of the corrected output torque ΔTM, that is, the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq is as follows. It is represented by the formula (10).

  When the phase term of the above equation (10) is 0 (Φ = 0), the following equations (11) and (12) are obtained.

  By generating the q-axis current correction value ΔIqk shown in the above equation (10) and superposing it on the q-axis current command value Iq0 *, the q-axis voltage Vq ′ shown in the equation (11) can be generated.

  In the present embodiment, as shown in FIG. 1, the phase / angular velocity detection unit 20 obtains the estimated position θm and the estimated angular velocity ωm of the rotor. Therefore, using the estimated position θe and the estimated angular velocity ωm obtained by the phase / angular velocity detector 20, the q-axis and the q-axis are orthogonal to a specific harmonic component (k harmonic) of the rotor speed fluctuation caused by the pulsation torque. A component on the axis, that is, a quadrature component is extracted, and the quadrature component is phase-converted to generate a k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq. The q-axis current output from the speed controller 33 is the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq output from the q-axis current correction value calculation processing unit 100. It is configured to be superimposed on the command value Iq0 *.

  The configuration and operation of the q-axis current correction value calculation processing unit 100 will be described with reference to FIG. 1, FIG. 2, and FIG. FIG. 6 is a diagram of a configuration example of the q-axis current correction value calculation processing unit of the motor control device according to the first embodiment.

  In the present embodiment, as shown in FIG. 2, a virtual axis (z-axis) orthogonal to the dq coordinate system is introduced, and the q-axis current correction value calculation processing unit 100 uses an angular velocity command ωm *. The k-harmonic component of the speed fluctuation included in the angular velocity difference Δωm, which is the difference between the estimated angular velocity ωm and the z-axis component ωzk and the q-axis component ωqk, is orthogonally decomposed and sequentially estimated for each basic period of the pulsating torque. By mapping (phase conversion) these estimated values (ωqk, ωzk) to the q-axis, a q-axis current that suppresses speed fluctuation on the q-axis based on the pulsation torque is calculated as a correction value ΔIqk. That is, the control by the q-axis current correction value calculation processing unit 100 does not affect the d-axis.

  As shown in FIG. 6, the q-axis current correction value calculation processing unit 100 includes a q-axis side fluctuation component calculation unit 101 and a q-axis side demodulation unit 102.

  The q-axis side fluctuation component calculation unit 101 includes a z-axis correlation processing unit 101a and a q-axis correlation processing unit 101b. The z-axis correlation processing unit 101a includes a z-axis frequency separator 103 and a z-axis repetition controller 105. The q-axis correlation processing unit 101b includes a q-axis frequency separator 104 and a q-axis repetition controller 106.

  The q-axis side demodulation unit 102 includes a phase converter 107 and a correction gain 108.

  First, the operation of the q-axis side fluctuation component calculation unit 101 will be described.

  The z-axis frequency separator 103 separates the k-th harmonic component of the z-axis component of the angular velocity difference Δωm output from the subtractor 32.

  The q-axis frequency separator 104 separates the k-th harmonic component of the q-axis component of the angular velocity difference Δωm output from the subtractor 32.

  The angular velocity difference Δωm is the difference between the angular velocity command ωm * at the mechanical angle of the rotor in the motor M and the estimated angular velocity ωm, and the rotor pulsation (periodic fluctuation according to the rotation angle of the rotor) accompanying this pulsation torque. In the vibration suppression control to be suppressed, spatial harmonics are controlled instead of temporal harmonics. For this reason, the z-axis frequency separator 103 and the q-axis frequency separator 104 are configured by correlators instead of bandpass filters, and correlation calculation processing is performed.

  The z-axis frequency separator 103 and the q-axis frequency separator 104 perform correlation calculation processing in one cycle of the fundamental wave component of the rotor speed fluctuation. The correlation calculation processing formula on the z-axis side is shown in the following formula (13), and the correlation calculation processing formula on the q-axis side is shown in the following formula (14).

  In the above formulas (13) and (14), the estimated position θm of the rotor expressed in mechanical angle can be obtained from the estimated position θe of the rotor expressed in electrical angle input from the phase / angular velocity detector 20. The same applies to the following description.

  In the above formulas (13) and (14), when k = 1, that is, when the fundamental wave component of the rotor speed fluctuation is the object of vibration suppression control, 0 to 0 in the fundamental wave period of the rotor speed fluctuation. A section up to 2π is set as a correlation processing calculation section. Further, for example, in the case of k = 3, that is, when the third harmonic component of the rotor speed fluctuation is to be controlled, the interval from 0 to 6π in the third harmonic period of the rotor speed fluctuation Is the correlation processing calculation interval. That is, in the present embodiment, one period of the fundamental wave component of the rotor speed fluctuation, that is, the mechanical angle of the rotor, for example, a single rotary compressor, a twin rotary compressor, or the like, regardless of the harmonic component to be subjected to vibration suppression control. Correlation calculation processing is performed in one rotation cycle.

  Assuming that the above equations (13) and (14) are discrete equations that are subjected to discrete calculation processing at the sampling period ts, the following equations (15) and (16) are obtained, respectively.

  In the above equations (15) and (16), n indicates a sampling point in the interval from 0 to 2 kπ, which is the base point of the correlation processing calculation.

  The square terms in the above equations (15) and (16) correspond to the square terms in the equation (10). By these formulas (15) and (16), the time harmonic is converted into a spatial harmonic and separated into a single k-th harmonic component in the spatial harmonic.

  1 and 6 and the above equations (13) to (16), the angular velocity difference Δωm, which is the difference between the angular velocity command ωm * and the estimated angular velocity ωm, is input to the q-axis current correction value calculation processing unit 100. However, instead of the angular velocity difference Δωm, the estimated angular velocity ωm may be input to the q-axis current correction value calculation processing unit 100. In this case, the above equations (13) to (16) are replaced with the following equations (17) to (20), respectively.

  When the estimated angular velocity ωm is input to the q-axis current correction value calculation processing unit 100, the angular velocity difference Δωm is changed to the q-axis because the dynamic range becomes large and it is easily affected by the speed control during acceleration / deceleration. The input of the current correction value calculation processing unit 100 is preferable.

  In the present embodiment, the equation (15) or the equation (19) is an arithmetic equation in the z-axis frequency separator 103, and the equation (16) or the equation (20) is an arithmetic equation in the q-axis frequency separator 104. And

  The z-axis repetitive controller 105 performs error correction on the output of the z-axis frequency separator 103 by adding a correction amount every time L (seconds). In the present embodiment, this time L is the fundamental wave period of the pulsating torque component. Specifically, the z-axis repetitive controller 105 uses the output value (z-axis component (ωzk)) one cycle before the fundamental wave period of the pulsating torque component as a correction error amount with respect to the output of the z-axis frequency separator 103. Are added and output.

  Similarly, the q-axis repetitive controller 106 performs error correction on the output of the q-axis frequency separator 104 by adding a correction amount for each fundamental wave period of the pulsating torque component. Specifically, the q-axis repetitive controller 106 uses the output value (q-axis component (ωqk)) one cycle before the fundamental wave period of the pulsating torque component as a correction error amount with respect to the output of the q-axis frequency separator 104. Are added and output.

  By repeating this process, a feedback loop is formed so that the calculation results of the z-axis frequency separator 103 and the q-axis frequency separator 104 become 0, and the amplitude and phase of the rotor speed fluctuation due to the pulsation torque are sequentially corrected. Is done.

  As described above, in this embodiment, the correlation processing calculation and error correction are performed in the fundamental wave period of the rotor speed fluctuation. For this reason, it is possible to save the memory required for the arithmetic processing.

Since the q-axis side fluctuation component calculation unit 101 performs calculation processing in synchronization with the rotational phase (θm) of the rotor, similarly to vector control, the time L has elapsed from the base point of the correlation processing calculation (that is, At the time of 0 to 2π in the fundamental wave period of the pulsating torque component), the orthogonal component (ωqk) of the k-th harmonic that is the z-axis component and the q-axis component at θm = 0 of the rotor speed fluctuation accompanying the pulsating torque , Ωzk) is determined. The orthogonal components (ωqk, ωzk) are the q-axis component and the z-axis component at θm = 0 of the k harmonic. Therefore, when this orthogonal component is used, the initial phase φ in the equation (6) can be expressed as φ = tan ⁻¹ (ωqk) / (ωzk). The phase of the k-th harmonic of the rotor speed fluctuation caused by the pulsation torque is an added value of the initial phase φ and the estimated position θm of the rotor.

  Next, the operation of the q-axis side demodulation unit 102 will be described.

  The damping current that cancels out the rotor speed fluctuation is handled as the current i on the dq coordinate, i.e., id, iq, and therefore needs to have a current value that varies according to the rotation of the rotor.

  The q-axis side demodulation unit 102 performs phase conversion on the quadrature components (ωqk, ωzk) output from the q-axis side fluctuation component calculation unit 101 as will be described later, and converts the k-th harmonic component ΔIqk of the q-axis correction current ΔIq. Generate.

  First, a general expression of a rotation matrix for rotating the orthogonal component (ωqk, ωzk) by θ is shown in the following expression (21).

  Here, the relationship between the rotor speed fluctuation caused by the pulsating torque and the canceling torque for canceling the pulsating torque will be described.

  In general, torque is proportional to acceleration. As can be seen from the equations (6) and (7), the phase of the angular velocity difference Δωm representing the rotor speed fluctuation component is delayed by π / 2 from the pulsating torque ΔT proportional to the acceleration. Therefore, the phase of the pulsating torque that causes the rotor speed fluctuation is advanced by π / 2 from the estimated position θm of the rotor.

  In order to cancel this pulsating torque, it is necessary to generate a canceling torque whose phase is inverted with respect to the phase of the pulsating torque. Accordingly, the canceling torque may be obtained by inverting the phase of the pulsating torque described above (that is, shifting the phase by 180 ° (± π)).

  Further, as shown in the equation (3), the torque and the current are in a proportional relationship. From the above, the phase of the canceling torque generation current (q-axis correction current ΔIq) is only π / 2-π or π / 2 + π from the estimated position θm of the rotor with respect to the initial phase of the speed fluctuation component of the rotor accompanying the pulsation torque. The phase is shifted. Therefore, the phase conversion in the phase converter 107 of the q-axis side demodulator 102 can be expressed as the following equation (22) when expressed using the rotation matrix of the above equation (21).

  In this embodiment, in order to obtain the q-axis side corrected AC component qr, the following equation (23) is used as an arithmetic expression in the phase converter 107.

  The k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq is generated by applying the correction gain 108 to the q-axis correction AC component qr obtained by the above equation (23). The

  The correction gain 108 determines a correction amount for converging a value sequentially estimated in the repetitive control, and has a function of determining a convergence value and a convergence speed.

  The calculation formula of the correction gain 108 is given by the following formula (24) from the formula (10). In addition, although it is a negative value notation in the expression (10), this negative sign indicates that the phase is inverted with respect to the q-axis current fluctuation component of the pulsation torque, and is introduced in the above expression (22). Therefore, the expression (24) is a positive value.

  In the above equation (24), Id0 is a negative current for generating the reluctance torque and is a variable. However, in the low rotation region where it is necessary to perform vibration suppression control that suppresses the pulsation of the rotor, the change in the d-axis current is For example, acceleration / deceleration when applied to a compressor of an air conditioner is small in the influence of the convergence speed of the vibration suppression control, so it is replaced with the constant value kR shown in the following equation (25). These may be treated as sequential correction processing. That is, the correction gain 108 also serves as a gain for compensating for stability in repetitive control, and can be an arbitrary value as long as it does not oscillate.

  At this time, the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq can be expressed by the following equation (26).

  The k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq generated as expressed by the above equation (26) is added to the q-axis current command value Iq0 * in the adder 43 shown in FIG. Thus, the k-th harmonic component of the speed fluctuation of the pulsating torque can be suppressed, and the rotation speed fluctuation accompanying the periodic load torque fluctuation can be suppressed.

  As described above, in the first embodiment, the specific harmonic of the rotor speed fluctuation caused by the pulsating torque is extracted using the estimated position θe (θm) and the estimated angular speed ωm obtained by the phase / angular velocity detector 20. A q-axis current correction value calculation processing unit 100 that phase-converts the specific harmonic (k-th harmonic) to generate a k-th harmonic component ΔIqk of the q-axis correction current ΔIq as a q-axis current correction value. The q-axis current correction value calculation processing unit 100 superimposes the q-axis current correction value ΔIqk on the q-axis current command value Iq0 * output from the speed controller 33, and the q-axis side fluctuation component calculation unit 101. , The angular velocity difference Δωm, which is the difference between the estimated angular velocity ωm or the angular velocity command ωm * and the estimated angular velocity ωm, is integrated over one period of the fundamental wave component of the rotor speed fluctuation caused by the pulsation torque, and correlation processing calculation and error correction are performed. The q-axis side demodulation unit 102 performs demodulation processing based on the rotor speed fluctuation accompanying the pulsating torque that is the output of the q-axis side fluctuation component calculation unit 101, and generates the q-axis current correction value ΔIqk. Therefore, it is not necessary to create a torque pattern in advance, and complicated processing such as Fourier transform and inverse Fourier transform, and many filters and memories are unnecessary. That is, without requiring a large number of development steps, fluctuations in rotational speed associated with periodic load pulsations can be suppressed with simpler control, and vibration and noise can be reduced.

  In the first embodiment, the z-axis is introduced as a virtual axis orthogonal to both the d-axis and the q-axis, and is included in the angular velocity difference Δωm that is the difference between the estimated angular velocity ωm or the angular velocity command ωm * and the estimated angular velocity ωm. Pulsation is obtained by orthogonally resolving k-harmonic velocity fluctuations into z-axis component ωzk and q-axis component ωqk and sequentially estimating each pulsating torque fundamental wave period, and mapping (phase conversion) these estimated values to q-axis. A q-axis current that suppresses speed fluctuation on the q-axis based on torque is calculated as a correction value ΔIqk. For this reason, it is possible to prevent the control in the q-axis current correction value calculation processing unit 100 from affecting the d-axis.

Embodiment 2. FIG.
In the first embodiment, a configuration has been described in which the specific harmonic component included in the fluctuation component of the load torque is canceled to suppress the rotor speed fluctuation caused by the pulsating torque. In the present embodiment, the q axis A configuration in which the current correction value calculation processing unit is multiplexed will be described.

  FIG. 7 is a block diagram in which q-axis current correction value calculation processing units are multiplexed. In the example illustrated in FIG. 7, the q-axis current correction value calculation processing unit 100-1 that controls the fundamental wave component of the speed fluctuation of the pulsating torque and the q-axis current correction value calculation process that uses the second harmonic component as the control target. An example is shown in which a unit 100-2 and a q-axis current correction value calculation processing unit 100-N with the Nth harmonic component as a control target are connected in parallel.

  FIG. 8 is a diagram illustrating a second variation example of the load torque with respect to the rotation angle of the single rotary compressor.

  Although different from the first variation example shown in FIG. 5 described in the first embodiment, in the variation example shown in FIG. 8, if the amplitude of the fundamental component of the variation component of the load torque is 100%, the second order The amplitude of the harmonic component is approximately 22%, and the amplitude of the third harmonic component is approximately 18%.

  In the second variation example shown in FIG. 8, the third harmonic component is included more than in the first variation example shown in FIG. 5, and the harmonic component included in the load torque variation component is the same even in the same single rotary compressor. It can be seen that the ratio is different.

  Further, in both the first variation example shown in FIG. 5 and the second variation example shown in FIG. 8, the apex portion of the load torque variation curve has an acute angle.

  FIG. 9 is a diagram illustrating an example of a combined waveform of the fundamental wave component and the second harmonic component of the load torque fluctuation component. The example shown in FIG. 9 shows an example in which the amplitude of the second harmonic component is 50% when the amplitude of the fundamental wave component of the load torque fluctuation component is 100%.

  In the first variation example shown in FIG. 5 and the second variation example shown in FIG. 8, the load torque variation curve is drawn such that the upper part is an acute angle and the lower part is flat. Here, assuming that the phase of the fundamental wave component and the second harmonic component of the fluctuation component of the load torque is as shown in FIG. 9, the combined waveform of the fundamental wave component and the second harmonic component is shown in FIG. The same curve as the first variation example and the second variation example shown in FIG. 8 is drawn. Therefore, the load torque fluctuation curve draws a curve in which the upper part has an acute angle and the lower part becomes flat like the first fluctuation example shown in FIG. 5 and the second fluctuation example shown in FIG. In this case, if the second harmonic component is the object of vibration suppression control in addition to the fundamental wave component of the speed fluctuation of the pulsating torque, the vibration suppression effect can be further enhanced.

  In this way, a plurality of harmonic components included in the speed fluctuation of the pulsating torque are controlled, and the q-axis current correction value calculation processing unit 100 is multiplexed as shown in FIG. Improvement can be expected.

  Further, in the present embodiment, the q-axis current correction value calculation processing units 100-1, 100-2, and 100-N shown in FIG. 7 all perform correlation processing in one cycle of the fundamental wave component of the speed fluctuation of the pulsating torque. Since calculation and error correction are performed, stable vibration suppression control can be performed without the control result of a harmonic component of a specific order affecting the control of harmonic components of other orders.

  Note that it is not a good idea in terms of control stability to control high-order harmonic components of pulsating torque speed fluctuations, and considering the processing speed, a microcomputer or the like used for vibration suppression control It is also disadvantageous in terms of the cost of the control means. Further, if the first variation example shown in FIG. 5 and the second variation example shown in FIG. 8 are taken into consideration, it is considered that the influence of the higher-order harmonic components is small. Therefore, a low-order harmonic component that has a large influence on load torque fluctuations may be controlled.

  As described above, in the second embodiment, a plurality of harmonic components included in the speed fluctuation of the pulsating torque are controlled, and the q-axis current correction value calculation processing unit 100 is multiplexed. The improvement of the vibration effect can be expected.

  In the second embodiment, the q-axis current correction value calculation processing units 100-1, 100-2, and 100-N all perform correlation processing calculation and error correction in one period of the fundamental wave component of the speed fluctuation of the pulsating torque. Therefore, stable vibration suppression control can be performed without the control result of the harmonic component of a specific order affecting the control of the harmonic component of another order.

Embodiment 3 FIG.
In the first embodiment, the configuration in which the fluctuation in the rotor speed caused by the pulsation torque is suppressed by controlling the q-axis current has been described. In this embodiment, the d-axis current is controlled in addition to the q-axis current. By doing so, the structure which improves the suppression effect of the rotational speed fluctuation accompanying the pulsation of a periodic load torque is demonstrated.

  FIG. 10 is a diagram of a configuration example of the motor control device according to the third embodiment. FIG. 11 is a diagram of a configuration example of the d-axis current correction value calculation processing unit of the motor control device according to the third embodiment. In addition, the same code | symbol is attached | subjected to the component which is the same as that of Embodiment 1, or equivalent, and the detailed description is abbreviate | omitted.

  As shown in FIG. 10, the motor control device 1a according to the third embodiment includes a d-axis current correction value calculation processing unit 200 and an adder 42 in addition to the configuration of the first embodiment shown in FIG. It is provided as a component of the unit 30.

  The d-axis current correction value calculation processing unit 200 receives the d-axis current detection value Id and the estimated position θe from the phase / angular velocity detection unit 20, and the k-th harmonic component ΔIdk of the d-axis correction current ΔId from the d-axis current detection value Id. (D-axis current correction value) is calculated and output to the adder 42.

  The adder 42 receives the d-axis current command value Id0 * from the outside, receives the k-th harmonic component ΔIdk of the d-axis correction current ΔId from the d-axis current correction value calculation processing unit 200, and receives the d-axis current command value Id0 *. The k-th harmonic component ΔIdk (d-axis current correction value) of the d-axis correction current ΔId is added, and the addition result is output to the subtractor 35a as a d-axis current command correction value Id *.

  The subtractor 35a receives the d-axis current command correction value Id * from the adder 42, receives the d-axis current detection value Id from the position / speed detection unit 20, and converts the d-axis current command correction value Id * to the d-axis current detection value. Id is subtracted, and the subtraction result is output to the d-axis current controller 36.

  As described in the first embodiment, the k-th harmonic component ΔIqk (q-axis current correction value) of the q-axis correction current ΔIq that suppresses the rotor speed fluctuation caused by the pulsating torque is superimposed on the q-axis current command value Iq0 *. Then, an induced voltage is generated accompanying rotation on the d-axis side due to interference. Due to the induced voltage generated on the d-axis side in accordance with the q-axis current correction control, pulsation of the d-axis current occurs.

  By controlling the d-axis voltage so as to cancel the third term of the equation (12) described in the first embodiment, the k-th harmonic component ΔIqk of the q-axis correction current ΔIq to the q-axis current command value Iq0 * Although it is considered that the pulsation of the d-axis current due to the superposition of the (q-axis current correction value) can be suppressed, the k-th harmonic component ΔIqk (of the q-axis correction current ΔIq obtained as in Embodiment 1 is used. Since the q-axis current correction value includes errors due to control delays of the phase / angular velocity detection unit 20 and the q-axis current correction value calculation processing unit 100, the k-th harmonic component ΔIqk (q By injecting the (axis current correction value) into the q-axis current command value Iq0 *, the influence on the d-axis current may be increased.

  Therefore, in the present embodiment, as shown in FIG. 10, using the d-axis current detection value Id output from the three-phase to two-phase converter 21 and the estimated position θe obtained by the phase / angular velocity detection unit 20, A component on an axis orthogonal to the d-axis and d-axis, that is, an orthogonal component is extracted from a specific harmonic (k harmonic) of current fluctuation on the d-axis, and the orthogonal component is phase-converted to obtain a d-axis correction current A d-axis current correction value calculation processing unit 200 that generates a k-th harmonic component ΔIdk (d-axis current correction value) of ΔId is provided, and a d-axis correction current ΔId output from the d-axis current correction value calculation processing unit 200. The k-th harmonic component ΔIdk (d-axis current correction value) is superimposed on the d-axis current command value Id0 *.

  The configuration and operation of the d-axis current correction value calculation processing unit 200 will be described with reference to FIGS. 10 and 11.

  In the present embodiment, similarly to the first embodiment, a virtual axis (z axis) orthogonal to the dq coordinate system is introduced, and the d axis current correction value calculation processing unit 200 uses the d axis current. The k-harmonic component of the d-axis current fluctuation included in the detection value Id is orthogonally decomposed into the d-axis component ωdk and the z-axis component ωzk (Idddk, Idzk) and sequentially estimated for each fundamental period of current fluctuation on the d-axis. . By mapping (phase conversion) these estimated values (ωdk, ωzk) to the d-axis, a d-axis current that suppresses current fluctuation on the d-axis is calculated as a correction value ΔIdk. In other words, the control by the d-axis current correction value calculation processing unit 200 does not affect the q-axis.

  As shown in FIG. 11, the d-axis current correction value calculation processing unit 200 includes a d-axis side fluctuation component calculation unit 201 and a d-axis side demodulation unit 202.

  The d-axis side fluctuation component calculation unit 201 includes a d-axis correlation processing unit 201a and a z-axis correlation processing unit 201b, and the d-axis correlation processing unit 201a includes a d-axis frequency separator 203 and a d-axis repetition controller 205. The z-axis correlation processing unit 201b includes a z-axis frequency separator 204 and a z-axis repetition controller 206.

  The d-axis side demodulation unit 202 includes a phase converter 207 and a correction gain 208.

  First, the operation of the d-axis side fluctuation component calculation unit 201 will be described.

  The d-axis frequency separator 203 separates the k-th harmonic component of the d-axis component of the d-axis current detection value Id output from the three-phase to two-phase converter 21.

  The z-axis frequency separator 204 separates the k-th harmonic component of the z-axis component of the d-axis current detection value Id output from the three-phase to two-phase converter 21.

  Similar to the z-axis frequency separator 103 and the q-axis frequency separator 104 described in the first embodiment, the d-axis frequency separator 203 and the z-axis frequency separator 204 are also configured by correlators instead of bandpass filters. Correlation calculation processing is performed.

  The d-axis frequency separator 203 and the z-axis frequency separator 204 perform correlation calculation processing in one cycle of the fundamental wave component of the current fluctuation on the d axis. The correlation calculation processing formula on the d-axis side is shown in the following formula (27), and the correlation calculation processing formula on the z-axis side is shown in the following formula (28).

  In the above formulas (27) and (28), when k = 1, that is, when the fundamental component of the current fluctuation on the d-axis is the object of vibration suppression control, the current fluctuation on the d-axis A section from 0 to 2π in the fundamental wave period is set as a correlation processing calculation section. Further, for example, in the case of k = 3, that is, when the third harmonic component of the current fluctuation on the d axis is set as the vibration suppression control target, in the third harmonic cycle of the current fluctuation on the d axis. A section from 0 to 6π is set as a correlation processing calculation section. That is, also in the present embodiment, as in the first embodiment, the correlation calculation process is performed in one cycle of the fundamental component of the current fluctuation on the d-axis, regardless of the harmonic component that is the object of vibration suppression control. .

  Assuming that the above equations (27) and (28) are discrete equations that are subjected to discrete calculation processing at the sampling period ts, the following equations (29) and (30) are obtained, respectively.

  In the above formulas (29) and (30), n indicates sampling points in the interval from 0 to 2 kπ, which is the base point of the correlation processing calculation. By these equations (29) and (30), the time harmonic is converted into a spatial harmonic and separated into a single k-th harmonic component in the spatial harmonic.

  In the present embodiment, the above expression (29) is an arithmetic expression in the d-axis frequency separator 203 and the above expression (30) is an arithmetic expression in the z-axis frequency separator 204.

  The d-axis repetition controller 205 performs error correction on the output of the d-axis frequency separator 203 by adding a correction amount every time L (seconds) (fundamental wave period of pulsating current component). Specifically, the d-axis repetitive controller 205 sets the output value (d-axis component (Idddk)) one cycle before the fundamental wave period of the pulsating current component with respect to the output of the d-axis frequency separator 203 as a correction error amount. Are added and output.

  Similarly, the z-axis repetitive controller 206 performs error correction on the output of the z-axis frequency separator 204 by adding a correction amount for each fundamental wave period of current fluctuation on the d-axis. Specifically, the z-axis repetition controller 206 outputs an output value (z-axis component (Idzk)) one period before the fundamental wave period of the current fluctuation on the d-axis with respect to the output of the z-axis frequency separator 204. Is added as a correction error amount and output.

  By repeating this process, a feedback loop is formed so that the calculation results of the d-axis frequency separator 203 and the z-axis frequency separator 204 become zero, and the amplitude and phase of the current fluctuation on the d-axis are sequentially corrected. The

  As described above, in the present embodiment, the correlation processing calculation and error correction are performed in one cycle of the fundamental wave component of the current fluctuation on the d-axis. For this reason, it is possible to save the memory required for the arithmetic processing.

  In the d-axis side fluctuation component calculation unit 201, the calculation process is performed in synchronization with the rotational phase θm of the rotor, similarly to the vector control, and therefore, when the time L has elapsed from the base point of the correlation process calculation (that is, d At the time when 0 to 2π in the fundamental wave period of the current fluctuation on the axis has elapsed), the d-axis component at θm = 0 of the k-th harmonic of the current fluctuation on the d-axis and the orthogonal component that is the z-axis component ( Iddk, Idzk) is determined. The orthogonal components (Idddk, Idzk) are a d-axis component and a z-axis component at km harmonic θm = 0. Therefore, when this orthogonal component is used, the initial phase φ in the equation (6) can be expressed as φ = tan−1 (Idzk) / (Idddk). The k-th harmonic phase of the current fluctuation on the d-axis is an addition value of the initial phase φ and the estimated position θm of the rotor.

  Next, the operation of the d-axis side demodulation unit 202 will be described.

  The damping current that cancels out the current fluctuation on the d-axis is handled as the current i on the dq coordinate, that is, Id, Iq, so it is necessary to set the current value to fluctuate according to the rotation of the rotor. is there.

  The d-axis side demodulation unit 202 performs phase conversion on the quadrature components (Idddk, Idzk) output from the d-axis side fluctuation component calculation unit 201 as described later, and converts the k-th harmonic component ΔIdk of the d-axis correction current ΔId to Generate.

First, a general expression of a rotation matrix for rotating the orthogonal components (Iddd, Idzk) by θ is shown in the following expression (31).

  Since the k-th harmonic component ΔIdk of the d-axis correction current is a current that cancels the third term of the equation (12) described in the first embodiment, the third term of the equation (12) is a cosine function. From this, it can be seen that the phase of current fluctuation on the d-axis is retarded by π / 2 with respect to the d-axis. Further, the damping current that cancels the current fluctuation on the d-axis, that is, the d-axis correction current ΔId has a phase-inverted relationship with respect to the current fluctuation on the d-axis.

  That is, the phase of the d-axis correction current ΔId is shifted from the initial phase of current fluctuation on the d-axis by −π / 2−π or −π / 2 + π from the estimated position θm of the rotor. Therefore, the phase conversion by the phase converter 207 of the d-axis side demodulator 202 can be expressed as the following equation (32) when expressed using the rotation matrix of the above equation (31).

  In the present embodiment, the following equation (33) is used as an arithmetic expression in the phase converter 207 in order to obtain the d-axis correction AC component dr.

  The k-th harmonic component ΔIdk (d-axis current correction value) of the d-axis correction current ΔId is generated by applying the correction gain 208 to the d-axis correction AC component dr obtained by the above equation (33). The

  Since the d-axis current correction value calculation processing unit 200 is configured to output a current with respect to the input current, the conversion coefficient is 1. Therefore, the correction gain 208 is a step gain for compensating the stability of the sequential correction in the repetitive control. Alternatively, if there is no problem in stability of repeated control, it may be handled as a constant value kR ′.

  At this time, the k-th harmonic component ΔIdk (d-axis current correction value) of the d-axis correction current ΔId can be expressed by the following equation (34).

  The k-th harmonic component ΔIdk (d-axis current correction value) of the d-axis correction current ΔId generated as described above is added to the d-axis current command value Id0 * in the adder 42 shown in FIG. The k-th harmonic component of the current fluctuation on the d-axis generated by the induced voltage generated on the d-axis side accompanying the correction control of the q-axis current described in the first embodiment can be suppressed, and the periodic load It is possible to enhance the effect of suppressing the rotational speed fluctuation accompanying the torque fluctuation.

  Furthermore, a configuration in which the d-axis current correction value calculation processing unit 200 is multiplexed is also conceivable. FIG. 12 is a block diagram in which d-axis current correction value calculation processing units are multiplexed.

  In the example shown in FIG. 12, the d-axis current correction value calculation processing unit 200-1 that controls the fundamental component of the current fluctuation on the d-axis and the d-axis current correction value that controls the second harmonic component. An example is shown in which an arithmetic processing unit 200-2 and a d-axis current correction value arithmetic processing unit 200-N whose control target is an Nth harmonic component are connected in parallel.

  In addition to the multiplexing of the q-axis current correction value calculation processing unit 100 described in the second embodiment, as shown in FIG. 12, the d-axis current correction value calculation processing unit 200 is multiplexed to reduce current fluctuation on the d-axis. By making a plurality of included harmonic components to be controlled, further improvement of the vibration damping effect can be expected.

  Further, in the present embodiment, each of the d-axis current correction value calculation processing units 200-1, 200-2, and 200-N shown in FIG. 12 is in one cycle of the fundamental wave component of current fluctuation on the d-axis. Since the correlation processing calculation and the error correction are performed, stable damping control can be performed without the control result of the harmonic component of a specific order affecting the control of the harmonic component of another order.

  FIG. 13 is a diagram illustrating an example of a damping characteristic when the fundamental wave component and the second harmonic component are controlled, and q-axis current correction and d-axis current correction are performed. In FIG. 13, the horizontal axis indicates the differential pressure of the compressor, and the vertical axis indicates the vibration amplitude with respect to the differential pressure of the compressor. In FIG. 13, a graph indicated by a solid line indicates a characteristic example when vibration suppression control is not performed, and a graph indicated by a broken line indicates a characteristic example when vibration suppression control is performed.

  As shown in FIG. 13, when vibration suppression control is performed, a very high vibration suppression effect is obtained regardless of whether the rotational speed is 22 (rps) or 35 (rps). The effect in the low rotation range of 22 (rps) is conspicuous.

  As described above, in the third embodiment, the d-axis current detection value Id output from the three-phase to two-phase converter 21 and the estimated position θe (θm) obtained by the phase / angular velocity detection unit 20 are used. A specific harmonic of current fluctuation on the axis is extracted, and the specific harmonic (kth harmonic) is phase-converted to generate the kth harmonic component ΔIdk of the d-axis corrected current ΔId as the d-axis current correction value. The d-axis current correction value calculation processing unit 200 is configured to superimpose the d-axis current correction value ΔIdk output from the d-axis current correction value calculation processing unit 200 on the d-axis current command value Id0 *. The side fluctuation component calculation unit 201 integrates the d-axis current detection value Id over one period of the fundamental wave component of the current fluctuation on the d axis to perform correlation processing calculation and error correction, and the d-axis side demodulation unit 202. On the d-axis, which is the output of the d-axis side fluctuation component calculation unit 201 The demodulating process based on the current fluctuation is performed to generate a d-axis current correction value ΔIdk. Therefore, the k-th harmonic component of the current fluctuation on the d-axis generated by the induced voltage generated on the d-axis side accompanying the correction control of the q-axis current described in the first embodiment can be suppressed, and the period It is possible to enhance the effect of suppressing rotational speed fluctuations associated with typical load torque fluctuations.

  Further, in the third embodiment, similarly to the first embodiment, the z-axis is introduced as a virtual axis orthogonal to both the d and q axes, and the k-harmonic included in the d-axis current detection value Id is on the d-axis. Current fluctuations at the time are orthogonally decomposed into a d-axis component Iddk and a z-axis component Idzk, sequentially estimated for each fundamental wave period of the current fluctuation on the d-axis, and these estimated values are mapped to the d-axis (phase conversion). Thus, the d-axis current that suppresses the current fluctuation on the d-axis is calculated as the correction value ΔIdk. For this reason, it is possible to prevent the control in the d-axis current correction value calculation processing unit 200 from affecting the q-axis.

  In the third embodiment, a plurality of harmonic components included in current fluctuations on the d-axis are controlled, and the d-axis current correction value calculation processing unit 200 is multiplexed to provide further control. The improvement of the vibration effect can be expected.

  In the third embodiment, each of the d-axis current correction value calculation processing units 200-1, 200-2, and 200-N performs correlation processing calculation in one cycle of the fundamental wave component of current fluctuation on the d-axis. Since the error correction is performed, stable vibration suppression control can be performed without the control result of the harmonic component of a specific order affecting the control of the harmonic component of another order.

  In the embodiment described above, an IPM motor used for a compressor such as a single rotary compressor or a twin rotary compressor is targeted, and the angular velocity and the rotation angle are estimated by a so-called sensorless method from the current flowing through the motor. It is also applicable to a configuration in which the rotational position of the rotor is directly detected by a sensor (encoder), and periodic vibration speed fluctuations can be suppressed by performing the vibration suppression control described in the embodiment. It is.

  The configurations described in the above embodiments are examples of the configurations of the present invention, and can be combined with other known techniques, and a part of the configurations is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

  As described above, the motor control device according to the present invention is useful for controlling the motor.

DESCRIPTION OF SYMBOLS 1,1a Motor control apparatus 10 Drive part 11 2-phase-3 phase converter 12 PWM modulator 13 Intelligent power module 20 Phase / angular velocity detection part 21 3-phase-2 phase converter 22 Axis error calculation process part 23 PLL controller 25 Converter 30 Voltage command generator 32 Subtractor 33 Speed controller 35, 35a Subtractor 36 d-axis current controller 37 Subtractor 41 Decoupling controller 45 Subtractor 46 q-axis current controller 47 Adder 50 Current detector 51, 52 Current sensor 61 Integrator 100, 100-1, 100-2, 100-N q-axis current correction value calculation processing unit 101 q-axis side fluctuation component calculation unit 101a z-axis correlation processing unit 101b q-axis correlation processing unit 102 q-axis side demodulator 103 z-axis frequency separator 104 q-axis frequency separator 105 z-axis repeat controller 106 q-axis repeat control 107 phase converter 108 correction gain 200, 200-1, 200-2, 200-N d-axis current correction value calculation processing unit 201 d-axis side fluctuation component calculation unit 201a d-axis correlation processing unit 201b z-axis correlation processing unit 202d Axis-side demodulator 203 d-axis frequency separator 204 z-axis frequency separator 205 d-axis repetition controller 206 z-axis repetition controller 207 phase converter 208 correction gain

Claims (10)

In a motor that drives a load whose load torque fluctuates periodically, a motor control device that performs vector control of the motor by decomposing a current flowing through the motor into a q-axis current and a d-axis current,
A speed controller that generates a current command value according to a speed difference that is a difference between the angular speed command and the angular speed;
a q-axis current controller that generates a q-axis voltage command value according to a q-axis current difference that is a difference between the q-axis current command value and the q-axis current detection value;
a d-axis current controller that generates a d-axis voltage command value in accordance with a d-axis current difference that is a difference between the d-axis current command value and the d-axis current detection value;
A q-axis current correction value calculation processing unit for generating a q-axis current correction value for correcting the q-axis current command value ;
The q-axis current correction value calculation processing unit
A q-axis side fluctuation component calculation unit that obtains a specific harmonic component of periodic velocity fluctuations included in the angular velocity by performing orthogonal processing on two axes orthogonal to each other and performing integration processing on a value corresponding to the angular velocity. When,
A q-axis side demodulator that generates the q-axis current correction value as a current value that suppresses periodic speed fluctuations based on the specific harmonic component and the position of the rotor of the electric motor;
Motor control device. The q-axis side fluctuation component calculation unit obtains the specific harmonic component by integrating a value corresponding to the angular velocity over one period of a fundamental wave component of a periodic fluctuation of the load torque.
The motor control device according to claim 1. The q-axis side fluctuation component computing unit performs the integration process by orthogonally decomposing a value corresponding to the angular velocity into a virtual axis and a q-axis orthogonal to the q-axis and the d-axis,
The motor control device according to claim 1 or 2. The q-axis side demodulator advances the phase of the specific harmonic component by π / 2, and inverts the advanced phase to obtain the phase of the q-axis current correction value.
The motor control apparatus as described in any one of Claim 1 to 3. The q-axis current correction value calculation processing unit is multiplexed corresponding to a plurality of harmonic components included in the angular velocity,
The motor control apparatus as described in any one of Claim 1 to 4. A d-axis current correction value calculation processing unit that generates a d-axis current correction value for correcting the d-axis current command value;
The d-axis current correction value calculation processing unit is
A d-axis side fluctuation component calculating unit for obtaining a specific harmonic component of periodic fluctuation components included in the detected d-axis current;
A d-axis side demodulator that generates the d-axis current correction value as a current value that suppresses periodic fluctuations based on the specific harmonic component and the position of the rotor of the electric motor;
The motor control apparatus as described in any one of Claim 1 to 5. The d-axis side fluctuation component calculation unit obtains the specific harmonic component by integrating the detected d-axis current over one cycle of the fundamental component of the fluctuation component.
The motor control device according to claim 6. The d-axis side fluctuation component calculation unit performs an integration process by orthogonally decomposing the detected d-axis current into a virtual axis orthogonal to the q-axis and the d-axis and the d-axis.
The motor control device according to claim 7. The d-axis side demodulation unit retards the phase of the specific harmonic component by π / 2 and inverts the advanced phase to obtain the phase of the d-axis current correction value.
The motor control apparatus as described in any one of Claim 6 to 8. The d-axis current correction value calculation processing unit is multiplexed corresponding to a plurality of harmonic components included in the detected d-axis current,
The motor control device according to any one of claims 6 to 9.

Images