JP7213196B2 - MOTOR DRIVE DEVICE, OUTDOOR UNIT OF AIR CONDITIONER USING THE SAME, MOTOR DRIVE CONTROL METHOD - Google Patents

Description

The present invention relates to a motor drive device for driving a motor (electric motor) and its control, and more particularly to a technique effectively applied to drive control of a motor (electric motor) used in applications requiring quietness.

The induced voltage of a permanent magnet synchronous motor ideally contains only the fundamental wave component, but in reality there are spatial harmonic components such as fifth and seventh order components on the three-phase stationary coordinates. The distortion component of the induced voltage contributes to pulsation of the motor torque, and this fluctuating torque becomes a source of excitation of mechanical resonance, causing noise and vibration.

Noise and vibration caused by mechanical resonance can be reduced, for example, by providing anti-vibration rubber at the location where the motor is fixed and at the rotary bearing. However, this method has the problem of complicating the structure as the number of parts increases and further increasing the cost.

For this reason, the development of a technique (hereinafter referred to as torque pulsation suppression control) to suppress torque pulsation, which is the source of excitation of mechanical resonance, by controlling a permanent magnet synchronous motor without using a member such as anti-vibration rubber. is underway.

When suppressing torque pulsation by control, it is necessary to grasp how much the distortion component of the induced voltage is included in generating the control command. As one means, it is conceivable to measure the motor characteristics including the induced voltage waveform in advance, but it is not easy to perform individual measurements for unspecified motors. In addition, it may be difficult to measure the motor characteristics of existing products.

As a background art of this technical field, there is a technique such as Patent Document 1, for example. In Patent Document 1, "The stator current is captured as a vector signal on an orthogonal two-axis dq synchronous coordinate system in which the rotor north pole phase is the d-axis phase, and current control is performed to follow the final current command value. means, compensation signal generating means for generating a compensation signal for compensating the initial torque command value or the initial current command value, compensating the initial torque command value or the initial current command value using the generated compensation signal, and final final current command value generating means for generating a current command value, the drive control device for a synchronous motor comprising real-time extraction of part or all of harmonic components contained in the induced voltage, and real-time extracted induced electromotive force A drive control device for a synchronous motor, characterized in that the compensation signal generating means is configured to generate a compensation signal by using at least a voltage harmonic component, a stator current equivalent value, and a rotor speed equivalent value. disclosed.

By estimating desired parameters online based on control commands and sensor information in the motor drive device as in Patent Document 1, high general-purpose applications such as fans and pumps equipped with unspecified motors can be achieved. It is possible to realize sexuality.

Further, Patent Document 2 describes "When a switching element is turned on and off by a switching command based on a dead time length command that determines the length of a dead time that is a protection period in which a switching element is turned off. A power converter that uses a current value supplied from a power converter to a load or a voltage command value for generating a switching command to find a compensation amount for compensating a voltage command value.

In addition, Patent Document 3 describes "a power conversion circuit that drives a permanent magnet motor and a control section that controls the power conversion circuit, and the control section includes a voltage command generation section and a torque ripple compensation section. , the torque ripple compensation unit includes an amplitude generation unit, a correction voltage generation unit, and an addition unit, the voltage command generation unit outputs a voltage command, the amplitude generation unit outputs a correction voltage amplitude, and the The corrected voltage generator outputs a corrected voltage command from the corrected voltage amplitude and the rotor position, the adder outputs a corrected voltage command from the voltage command and the corrected voltage command, and outputs the corrected voltage command to the corrected voltage command. A motor drive device for operating the power conversion circuit based on the above is disclosed.

JP 2012-100510 A JP 2018-182901 A JP 2017-229126 A

By the way, the distortion component of the induced voltage in the permanent magnet synchronous motor contains 5th order and 7th order components on the three-phase stationary coordinates as described above. These order components appear as sixth order components on the two-axis rectangular coordinates (hereinafter referred to as dq coordinates) synchronized with the electrical rotation of the motor. From this, by constructing an observer as disclosed in the above-mentioned Patent Document 1 on the dq coordinates, based on the sixth-order component included in the control command and sensor information, the distortion component of the induced voltage corresponding to the disturbance can be estimated.

However, when the sixth-order component is contained in the control command or sensor information due to multiple factors, the method disclosed in Patent Document 1 cannot isolate the influence of each factor, so the distortion component of the induced voltage can be accurately detected. There was a problem that it became impossible to estimate.

Another factor that causes the sixth-order component in the control command or sensor information is the output voltage error caused by the inverter. The inverter supplies power to the motor by operating switching elements, and sets a period (hereinafter also referred to as dead time) during which the switching elements are simultaneously turned off in order to prevent a short circuit between the upper and lower arms. Accompanying this, the output voltage of the inverter deviates from the command voltage, and a sixth-order disturbance voltage is generated on the dq coordinates.

From the above, when realizing torque ripple suppression control in the presence of induced voltage distortion caused by the motor and output voltage distortion caused by the inverter at the same time, these effects can be separated from the control command and sensor information and individually A means of estimating and compensating for relevant parameters is needed.

The above-mentioned Patent Document 2 discloses effective means for separating the above two effects from the detected current. In this method, the length of the dead time, which is normally set constant, is changed in cycles other than the sixth order, thereby avoiding interference with the distortion component of the induced voltage that changes in the sixth order cycle.

Although Patent Document 2 compensates for output voltage distortion caused by an inverter, it is considered that more effective torque ripple suppression control can be realized by combining existing means for compensating for induced voltage distortion caused by a motor. However, when changing the length of the dead time, it is necessary to ensure that the lower end value of the setting with a width does not fall below the OFF period required to prevent short-circuiting between the upper and lower arms, which complicates the control design. put away.

In addition, in fan and pump applications, an inexpensive driving device is used, and it is sometimes difficult to periodically change the dead time as in Patent Document 2.

Accordingly, an object of the present invention is to provide a motor drive device capable of effectively suppressing torque pulsation due to induced voltage distortion caused by a motor and output voltage distortion caused by an inverter, an outdoor unit of an air conditioner using the same, and a motor drive control method. is to provide

In order to solve the above-described problems, the present invention provides a power conversion circuit that supplies power to a motor, a control unit that controls the power conversion circuit, a current sensor that detects a three-phase current supplied to the motor, The control unit includes a command voltage calculation unit that calculates a command voltage that contributes to driving the motor, and a three-phase detection current detected by the current sensor based on each component separated into mutually orthogonal components. A pulsating current detector that generates a first component and a second component by extracting the pulsating component of each component, and outputs a first compensation command voltage that compensates for torque pulsation caused by the structure of the motor based on the first component. and a dead time compensator outputting a second compensation command voltage for compensating output voltage distortion caused by the dead time of the power conversion circuit based on the second component, wherein the second The torque ripple and the output voltage distortion are reduced by correcting the command voltage with the first compensation command voltage and the second compensation command voltage.

The present invention also provides a permanent magnet synchronous motor, a motor driving device for driving the permanent magnet synchronous motor, a fan connected to the permanent magnet synchronous motor, a frame for mounting the permanent magnet synchronous motor, and a compressor device. system, wherein the motor driving device is a motor driving device having the above characteristics.

In addition, the present invention detects a three-phase current supplied to a motor, separates the detected three-phase current into mutually orthogonal components, and extracts the pulsation component of each component to obtain a first component and a second component. generating, based on the first component, a first compensating command voltage that compensates for torque ripple caused by the structure of the motor; and based on the second component, output voltage distortion caused by dead time of a power conversion circuit. and correcting the command voltage contributing to the driving of the motor with the first compensation command voltage and the second compensation command voltage, thereby reducing the torque ripple and the output voltage distortion It is characterized by reducing

According to the present invention, there is provided a motor drive device capable of effectively suppressing torque pulsation due to induced voltage distortion caused by a motor and output voltage distortion caused by an inverter, an outdoor unit of an air conditioner using the same, and a motor drive control method. can do.

As a result, motor noise and vibration can be reduced without the need for preliminary adjustments such as preliminary tests, and a highly versatile motor drive device compatible with a variety of motors, and an air conditioner outdoor unit using the same, A motor drive control method can be realized.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a figure which shows the structure of the motor drive device which concerns on Example 1 of this invention. 2 is a diagram expressing a part of the configuration of FIG. 1 on dq coordinates; FIG. It is a figure which shows an example of the voltage distortion waveform for every factor. FIG. 5 is a diagram showing loci of current vectors and voltage distortion components when only a q-axis current is applied; 2 is a diagram showing the configuration of a pulsating current detection unit 116 in FIG. 1; FIG. FIG. 2 is a diagram showing the configuration of a torque ripple compensator 109 in FIG. 1; FIG. FIG. 2 is a diagram showing the configuration of a dead time compensator 112 in FIG. 1; FIG. It is a figure which shows an example of the operation|movement waveform of the motor drive device which concerns on Example 1 of this invention. It is a figure which shows the structure of the motor drive device which concerns on Example 2 of this invention. FIG. 10 is a diagram showing the configuration of a torque ripple compensator 109' in FIG. 9; It is a figure which shows an example of the operation|movement waveform of the motor drive device which concerns on Example 2 of this invention. FIG. 4 is a diagram showing loci of current vectors and voltage distortion components when d-axis and q-axis currents are applied; It is a figure which shows the structure of the motor drive device which concerns on Example 3 of this invention. 14 is a diagram showing the configuration of a pulsating current detection unit 116' in FIG. 13; FIG. FIG. 4 is a diagram showing an outdoor unit of an air conditioner according to Embodiment 4 of the present invention;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same configurations are denoted by the same reference numerals, and detailed descriptions of overlapping portions are omitted.

A motor driving device and a control method thereof according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 8. FIG.

FIG. 1 is a configuration diagram of the motor drive device of this embodiment. As shown in FIG. 1, the motor drive device 100 of the present embodiment includes a command speed generation unit 102, a control unit 103, and a power source for supplying power to a permanent magnet synchronous motor 101 (hereinafter simply referred to as "motor"). A conversion circuit 104 (hereinafter also referred to as an “inverter”) and a current sensor 105 are provided. In this embodiment, the motor driving device 100 includes the command speed generating section 102 , but it may be provided inside the control section 103 or outside the motor driving device 100 .

Control unit 103 generates three-phase command voltages Vu*, Vv*, Vw based on command speed ωr* given from command speed generation unit 102 and three-phase detection currents Iu, Iv, Iw detected by current sensor 105. * is output, and the rotation speed of the motor 101 is controlled. In this embodiment, the current of all three phases is detected by the current sensor 105, but even if the current sensor 105 detects any two phases and the remaining one phase is calculated by the control unit 103 good.

The power conversion circuit 104 performs PWM (Pulse Width Modulation) control based on the three-phase command voltages Vu*, Vv*, and Vw* output from the control unit 103, and generates a pulse-shaped output voltage, thereby controlling the motor 101. to drive.

The control unit 103 has vector control as a basic configuration. The command speed ωr* input from the command speed generation unit 102 to the control unit 103 is multiplied by the gain “number of motor poles P/2” in the gain multiplication unit 106 to calculate the electrical angular velocity (P/2)·ωr*. be.

A command voltage calculation unit 107 calculates a q-axis command current Iq* calculated from a preset d-axis command current Id* and a q-axis detection current Iqc through a low pass filter (LPF) 108, an electrical angular velocity (P /2) d-axis and q-axis command voltages Vdc* and Vqc* are calculated based on ωr* and set values of motor constants. The d-axis and q-axis command voltages Vdc* and Vqc* are direct-current command voltages that contribute to the rotation of the motor 101 .

A torque ripple compensator 109 calculates d-axis and q-axis compensation command voltages ΔVd* and ΔVq* for compensating for the influence of induced voltage distortion caused by the motor. The d-axis and q-axis compensation command voltages ΔVd* and ΔVq* are added to the d-axis and q-axis command voltages Vdc* and Vqc* in an adder 110 to obtain post-compensation d-axis and q-axis command voltages Vdc** and Vqc** is generated. The adder 110 is composed of adders 110a and 110b.

A dq/three-phase converter 111 converts the compensated d-axis and q-axis command voltages Vdc** and Vqc** into three-phase command voltages Vu*, Vv* and Vw* based on the rotor position θdc.

Dead time compensator 112 generates three-phase compensation command voltages ΔVu*, ΔVv*, ΔVw* for compensating for the influence of output voltage distortion caused by the inverter. Three-phase compensation command voltages ΔVu*, ΔVv*, ΔVw* are added to three-phase command voltages Vu*, Vv*, Vw* in adder 113 to obtain three-phase command voltages Vu**, Vv** after compensation. , Vw** are generated and input to the power conversion circuit 104 . The adder 113 is composed of adders 113a, 113b, and 113c.

Rotor position detector 114 sets d-axis and q-axis command voltages Vdc* and Vqc*, d-axis and q-axis detection currents Idc and Iqc, electrical angular velocity (P/2)·ωr*, and motor constants. Based on the values, an axis error Δθc, which is a phase deviation between the control axis (dc axis) and the motor magnetic flux axis (d axis), is calculated. Then, the electrical angular velocity is controlled by a PLL (Phase Locked Loop) so that Δθc becomes zero, and the obtained value is integrated to calculate the rotor position θdc. That is, this embodiment constitutes sensorless vector control that does not require a position sensor.

A three-phase/dq converter 115 converts the three-phase detection currents Iu, Iv, Iw into d-axis and q-axis detection currents Idc, Iqc based on the rotor position θdc.

In the pulsating current detection unit 116, based on the rotor position θdc and the d-axis and q-axis detection currents Idc and Iqc, a first component Ih1 and a second component which are pulsation components of the d-axis and q-axis detection currents Idc and Iqc are detected. Extract Ih2. The first component Ih1 is input to the torque ripple compensator 109, and the second component Ih2 is input to the dead time compensator 112, where they are used for parameter estimation calculations related to compensation control.

That is, in this embodiment, the influence of induced voltage distortion caused by the motor and the influence of the output voltage distortion caused by the inverter appear as pulsating components of the d-axis and q-axis detection currents Idc and Iqc. Control is performed by appropriately extracting in the unit 116 .

The above is the basic configuration of this embodiment.

In the command voltage calculator 107, based on the d-axis command current Id*, the q-axis command current Iq*, the electrical angular velocity (P/2)·ωr*, and the set values of the motor constants, according to the following equation (1): d-axis and q-axis command voltages Vdc* and Vqc* are calculated.

In equation (1), R is the winding resistance, Ld is the d-axis inductance, Lq is the q-axis inductance, Ke is the induced voltage coefficient, and the superscript * means the set value of each motor constant.

The command voltage calculator 107 uses a constant value set in advance as the d-axis command current Id*, and uses a value obtained by low-pass filtering the q-axis detection current Iqc by the LPF 108 as the q-axis command current Iq* to obtain the formula ( 1) is calculated.

Therefore, in a steady state in which the motor 101 is driven at a constant speed, the d-axis command current Id* and the q-axis command current Iq* are constant, and the d-axis and q-axis command voltages Vdc* and Vqc* are also becomes constant.

In rotor position detection unit 114, d-axis and q-axis command voltages Vdc* and Vqc*, d-axis and q-axis detection currents Idc and Iqc, electrical angular velocity ω1c, and motor constant The axis error Δθc is calculated based on the set value.

In equation (2), the electrical angular velocity ω1c is a signal obtained by adjusting the electrical angular velocity so that the axis error Δθc becomes zero by the PLL. The rotor position detector 114 calculates the rotor position θdc by integrating the electrical angular velocity ω1c.

When the motor 101 is driven with the above configuration, the effects of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter appear as the pulsating components of the d-axis and q-axis detection currents Idc and Iqc, as described above. . This principle will be described below with reference to FIG.

FIG. 2 shows elements necessary for explanation in the configuration shown in FIG. Also, the permanent magnet synchronous motor 200 is shown as an equivalent model on dq coordinates. In the subtraction units 201a and 201b, the distortion components Kehd and Kehq of the induced voltage coefficients on the d-axis and the q-axis are multiplied by the electrical angular velocity (P/2)·ωr to obtain (P/2)·ωr·Kehd, (P/2 )·ωr·Kehq is subtracted.

That is, the subtraction units 201a and 201b equivalently express the influence of the induced voltage distortion caused by the motor on the dq coordinates.

Subtraction units 202a and 202b subtract output voltage distortions Vtdd and Vtdq due to dead time on the d-axis and q-axis.

That is, the subtraction units 202a and 202b equivalently express the influence of the output voltage distortion caused by the inverter on the dq coordinates.

In FIG. 2, the solid-line arrow indicates "DC amount + AC amount", and the dotted-line arrow indicates "only DC amount".

As shown in FIG. 2, when there is induced voltage distortion caused by the motor and output voltage distortion caused by the inverter, the d-axis and q-axis command voltages Vdc* and Vqc* generated by the command voltage calculation unit 107 are respectively supplied with AC voltages. The quantities "(P/2)·ωr·Kehd+Vtdd" and "(P/2)·ωr·Kehq+Vtdq" are subtracted.

As a result, the permanent magnet synchronous motor 200 is energized with the pulsation components Idh and Iqh in addition to the DC components Id and Iq on the d-axis and the q-axis, respectively. Of these currents, the q-axis current “Iq − +Iqh” is converted to the q-axis command current Iq* via the LPF 108 and fed back to the command voltage calculation unit 107 . At this time, it is assumed that the cutoff frequency of the LPF 108 is made sufficiently smaller than the variation frequency of the pulsating component Iqh of the q-axis current so that Iq*=Iq.sup.-.

As a result, the d-axis and q-axis command voltages Vdc* and Vqc* generated by the command voltage calculator 107 are DC amounts, and only the DC components Id and Iq of the d-axis and q-axis currents are controlled.

On the other hand, since the pulsating components Idh and Iqh remain as they are regardless of the command voltage calculation unit 107, by detecting these current pulsating components, the induced voltage distortion "(P/2)·ωr·Kehd, ( P/2)·ωr·Kehq” and the output voltage distortion “Vtdd, Vtdq” caused by the inverter can be observed.

Here, it is assumed that the distortion components of the induced voltage coefficients on the d-axis and the q-axis are equal (Kehd=Kehq). Also, the output voltage distortion due to dead time is represented by the following equation (3) on static coordinates.

In equation (3), Td is the length of the dead time, fc is the carrier frequency, VDC is the DC voltage applied to the inverter, and sign(i) means the polarity of the detection current of each phase.

FIG. 3 shows the induced voltage distortion "(P/2)·ωr·Kehd, (P/2)·ωr· Kehq" and inverter-induced output voltage distortions "Vtdd, Vtdq".

As shown in FIG. 3, the induced voltage distortion "(P/2)·ωr·Kehd, (P/2)·ωr·Kehq" caused by the motor has the same amplitude on the d-axis and the q-axis. The pulsating voltages are out of phase with each other by 90°. On the other hand, the output voltage distortion “Vtdd, Vtdq” due to the inverter has a sawtooth waveform on the d-axis and a half-wave waveform on the q-axis.

From the viewpoint of pulsation amplitude, Vtdd on the d-axis side is larger than Vtdq on the q-axis side, so the output voltage distortion due to the inverter appears prominently on the d-axis side, that is, on the non-energized axis side. I understand.

If this characteristic is illustrated on the dq coordinates, it can be expressed as shown in FIG. In FIG. 4, I is a current vector (only the q-axis current is applied), X is the trajectory of the induced voltage distortion caused by the motor, and Y is the trajectory of the output voltage distortion caused by the inverter. X has a circular trajectory, while Y has a half-moon trajectory.

In addition, when expressed as a mathematical expression focusing only on the sixth-order component, the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter are expressed by the following equations (4) and (5), respectively.

where Keh is the amplitude of Kehd and Kehq in equation (4). Also, in equation (5), Vtdd and Vtdq are the amplitudes of Vtdd and Vtdq.

In this embodiment, the pulsating current detector 116 for extracting the pulsating components of the d-axis and q-axis detection currents Idc and Iqc is configured as shown in FIG.

As described above, the output voltage distortion caused by the inverter appears mainly on the d-axis side, which is the non-energized axis. ing.

More specifically, assuming that the fluctuation frequency of Vtdd is sufficiently fast (that is, the motor speed is sufficiently fast), the current phase lags the voltage phase by 90°, and from equation (5), the main Since the component Vtdd is a function of sin θd, the multiplier 501 multiplies the d-axis detection current Idc by cos 6 θdc to detect the effect of output voltage distortion caused by the inverter. The LPF 502 extracts the DC amount of Idc·cos6θdc, which is the calculation result of the multiplication section 501, and outputs the second component Ih2.

On the other hand, from the q-axis detection current Iqc, the first component Ih1 used in the torque ripple compensator 109 is extracted as the influence of the induced voltage distortion caused by the motor.

More specifically, since (P/2)·ωr·Kehq is a function of cos6θd from equation (4), multiplier 504 multiplies q-axis detection current Iqc by sin6θdc. The LPF 505 extracts the direct current amount of Iqc·sin6θdc, which is the calculation result of the multiplication section 504, and outputs the first component Ih1.

In this embodiment, the pulsating current detector 116 includes the LPF 502 and the LPF 505, but the configuration may be such that these LPFs are omitted. This is because the torque ripple compensator 109 and the dead time compensator 112 are provided with integral control based on the first component Ih1 and the second component Ih2, and as a result, the alternating current amounts of Idc·cos6θdc and Iqc·sin6θdc are canceled. This is because Details will be described later.

FIG. 6 is a configuration diagram of the torque ripple compensator 109. As shown in FIG. A torque ripple compensator 109 compensates for torque ripple generated by induced voltage distortion caused by the motor based on the first component Ih1 extracted by the ripple current detector 116 and the electrical angular velocity (P/2)·ωr*. d-axis and q-axis compensation command voltages ΔVd* and ΔVq* for

First, in the integral control section 600, an adjustment signal ΔKeh is generated according to the first component Ih1 of the current pulsation. The adjustment signal ΔKeh is added to the initial value Keh0 set by the initial value setting unit 602 in the addition unit 601 to generate the set value Keh*.

Thereafter, Keh* is multiplied by sin6θdc generated by sin6θdc signal generator 603 and electrical angular velocity (P/2)·ωr* in multipliers 604 and 607, respectively, to generate d-axis compensation command voltage ΔVd*. Similarly, the cos6θdc generated by the cos6θdc signal generator 605 and the electrical angular velocity (P/2)·ωr* are multiplied by Keh* in multipliers 606 and 608, respectively, to generate the q-axis compensation command voltage ΔVq*. .

In this embodiment, the value set by the initial value setting unit 602 is the initial value Keh0, but any value can be set for control, and zero may be set.

As shown in FIG. 1, the d-axis and q-axis compensation command voltages ΔVd* and ΔVq* are added to the d-axis and q-axis command voltages Vdc* and Vqc* in an adder 110 to Command voltages Vdc** and Vqc** are generated.

In FIG. 2, if the compensated d-axis and q-axis command voltages Vdc** and Vqc** are applied instead of the d-axis and q-axis command voltages Vdc* and Vqc*, the adder 201a in the permanent magnet synchronous motor 200 and (P/2)·ωr·Kehd and (P/2)·ωr·Kehq added in 201b are respectively the d-axis compensation command voltage ΔVd* in the d-axis command voltage Vdc** after compensation and q after compensation. It is canceled by the q-axis compensation command voltage ΔVq* in the axis command voltage Vqc**, and the influence of the induced voltage distortion caused by the motor is compensated.

FIG. 7 is a configuration diagram of the dead time compensator 112. As shown in FIG. Based on the second component Ih2 extracted by the pulsating current detector 116 and the three-phase detected currents Iu, Iv, and Iw, the dead time compensator 112 compensates for the influence of output voltage distortion caused by the inverter. Compensation command voltages ΔVu*, ΔVv*, ΔVw* are generated.

First, in the integral control section 700, an adjustment signal ΔVtd is generated according to the second component Ih2 of the current ripple. The adjustment signal ΔVtd is added by the adder 702 to the initial value Vtd0 set by the initial value setting unit 701 to generate the set value Vtd*.

After that, Vtd* is multiplied by a signal of 1 or -1 corresponding to the polarity of the U-phase detection current Iu generated by the sign function section 703 in the multiplication section 704 to generate the U-phase compensation command voltage ΔVu*. Similarly, Vtd* is multiplied by the signal generated by the sign function unit 705 in the multiplication unit 706 to generate the V-phase compensation command voltage ΔVv*. Further, Vtd* is multiplied by the signal generated by the sign function unit 707 in the multiplication unit 708 to generate the W-phase compensation command voltage ΔVw*.

In this embodiment, the value set by the initial value setting unit 701 is the initial value Vtd0, but any value can be set for control, and zero may be set.

As shown in FIG. 1, the three-phase compensation command voltages ΔVu*, ΔVv*, and ΔVw* are added to the three-phase command voltages Vu*, Vv*, and Vw* in the adder 113, and the three-phase compensation command voltages after compensation are obtained. Vu**, Vv** and Vw** are generated.

Here, ΔVd** and ΔVq** are obtained by converting the three-phase compensation command voltages ΔVu*, ΔVv* and ΔVw* into dq-axis components, and these command voltages are the d-axis and q-axis command voltages Vdc* and Vqc. The values added to * are Vd*** and Vq***.

In FIG. 2, if Vdc*** and Vqc*** are applied instead of Vdc* and Vqc*, Vtdd and Vtdq added by the adders 202a and 202b will be ΔVd** and Vqc* in Vdc***, respectively. It is canceled by ΔVq** in ** to compensate for the effect of inverter-induced output voltage distortion.

FIG. 8 shows the operating waveforms of this embodiment. However, the d-axis command current Id* is set to zero, and the initial value Keh0 of the torque ripple compensator 109 and the initial value Vtd0 of the dead time compensator 112 are set to zero. In FIG. 8, time T1 is the time when torque ripple compensator 109 starts operating (integral controller 600 starts operating), and time T2 is the time when dead time compensator 112 starts operating (integral controller 700 starts operating). to start).

At time T1<t<T2, when the torque pulsation compensator 109 operates, the pulsation component of the q-axis detection current Iqc decreases and the set ratio of the set value Keh* to the actual value Keh increases. I understand. This is because the set value Keh* is adjusted by the integral control unit 600 based on the first component Ih1 of the current pulsation, that is, the pulsation of the q-axis detection current Iqc.

However, the ratio Keh*/Keh is less than 1, and "set value Keh*=actual value Keh" does not hold. This is because the output voltage distortion Vtdq due to the inverter exists on the q-axis side as shown in FIG.

When the dead time compensator 112 operates at time T2<t, the pulsation component of the d-axis detection current Idc decreases and the set ratio of the set value Vtd* to the actual value Vtd increases. I understand. This is because the set value Vtd* is adjusted by the integral control unit 700 based on the second component Ih2 of the current ripple, that is, the ripple of the d-axis detected current.

At the same time, the setting ratio of the set value Keh* to the actual value Keh also changes. This is because the dead time compensator 112 compensates for the effect of the output voltage distortion Vtdq caused by the inverter in the torque ripple compensator 109, and the error contained in the adjustment signal ΔKeh produced by the integral controller 600 is removed. .

As a result, both the ratio Vtd*/Vtd and the ratio Keh*/Keh converge to around 1, and "set value Vtd*=actual value Vtd" and "set value Keh*=actual value Keh" ” is controlled.

In this way, the present invention separates the effects of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter from the detected current and separately estimates the related parameters to compensate ( correction).

In FIG. 8, the operation start times of torque ripple compensator 109 and dead time compensator 112 are staggered (T1≠T2), but these compensators may start operating at the same time (T1=T2).

A motor driving device and a control method thereof according to a second embodiment of the present invention will be described with reference to FIGS. 9 to 11. FIG.

In the first embodiment, the torque ripple compensator 109 and the dead time compensator 112 operate to compensate for the effects of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter in FIG. (the terms added by the adders 202a and 202b are canceled), and constant d-axis and q-axis currents Id and Iq that do not include the pulsating components Idh and Iqh are applied. That is, the torque ripple reduction effect is obtained by bringing the current waveform distorted by various factors closer to an ideal sinusoidal waveform.

However, even if constant d-axis and q-axis currents Id and Iq are applied in FIG. is limited. (See torque waveform in Fig. 8)
Therefore, in order to compensate for the torque pulsation, the method disclosed in Patent Document 3 may be used, for example. That is, the q-axis current may be intentionally controlled to pulsate so that the torque pulsation is canceled out.

FIG. 9 is a configuration diagram of the motor drive device of this embodiment. This configuration is obtained by replacing the torque ripple compensator 109 in the configuration of the first embodiment (FIG. 1) with a torque ripple compensator 109'.

FIG. 10 shows the configuration of the torque ripple compensator 109'. The difference from the torque ripple compensator 109 of the first embodiment (FIG. 1) is that the q-axis detection current Iqc is input, the compensation voltage calculator 1000, the LPF (low pass filter) 1002, and the multipliers 1003 and 1004. , 1006, 1007 and adders 1005, 1008 are added.

A low-pass filter (LPF) 1002 extracts the DC quantity of the q-axis detection current Iqc to generate Iqc.

The set value Keh* of the distortion component of the induced voltage coefficient, Iqc by the LPF 1002, and the electrical angular velocity (P/2) ωr* are input to the compensation voltage calculation unit 1000, and based on the following equation (6): to generate a first d-axis compensation command voltage ΔVd1*, a second d-axis compensation command voltage ΔVd2*, a first q-axis compensation command voltage ΔVq1*, and a second q-axis compensation command voltage ΔVq2*.

ΔVd1* and ΔVd2*, which are the calculation results of compensation voltage calculation unit 1000, are multiplied by sin6θdc and cos6θdc in multipliers 1003 and 1004, respectively, to generate ΔVd1*sin6θdc and ΔVd2*cos6θdc. be. After that, these calculation results are added together in the addition section 1005 to generate the d-axis compensation command voltage ΔVd*.

Similarly, ΔVq1* and ΔVq2* are multiplied by sin6θdc and cos6θdc in multipliers 1006 and 1007, respectively, to generate ΔVq1*sin6θdc and ΔVq2*cos6θdc. After that, these calculation results are added in addition section 1008 to generate q-axis compensation command voltage ΔVq*.

When the d-axis and q-axis compensation command voltages ΔVd* and ΔVq* generated in the configuration of this embodiment are applied, the q-axis current given by equation (7) is supplied in the steady state.

By energizing the q-axis current including the pulsating component shown in the equation (7), the torque pulsation can be reduced by the ratio "ΔKeh /Ke" compared to the configuration of the first embodiment.

FIG. 11 shows the operating waveforms of this embodiment. The operating conditions are the same as those of the first embodiment shown in FIG. 8, and the only difference is that the torque ripple compensator 109 is replaced with a torque ripple compensator 109'. When compared with FIG. 8, which shows the operating waveforms of Example 1, the torque and current waveforms are different. In the present embodiment, the q-axis current Iq intentionally containing pulsation is applied at time T1<t, and it can be seen that a higher torque pulsation reduction effect is obtained.

Thus, in this embodiment, even under the condition that the output voltage distortion due to the inverter exists, the distortion component Keh of the induced voltage coefficient can be estimated from the detected current, and based on the obtained Keh By intentionally energizing the pulsating current, the torque pulsation can be canceled more effectively.

A motor driving device and a control method thereof according to a third embodiment of the present invention will be described with reference to FIGS. 12 to 14. FIG.

As described above, the output voltage distortion due to the inverter appears prominently on the non-energized shaft side. Therefore, if the direction of the current vector can be observed and the directions of the energized axis and the non-energized axis can be grasped, the same control operation as in the first and second embodiments can be realized even under other energizing conditions.

Here, the angle formed by the d-axis current Id and the q-axis current Iq is defined as the current phase β (=tan-1(-Id/Iq)). FIG. 12 shows the current vector I', the locus X' of the induced voltage distortion caused by the motor, and the locus Y' of the output voltage distortion caused by the inverter when the current phase β is set to 45°.

When compared to the case of FIG. 4 in which only the q-axis current is energized, the trajectories X and X' are similar, and it can be seen that the influence of the induced voltage distortion caused by the motor does not depend on the current. On the other hand, the trajectories Y and Y' are different from each other, and the influence of the output voltage distortion caused by the inverter changes along with the direction of the current vector. If the direction of the current vector, that is, the conducting direction is the δ-axis, and the non-conducting direction with a 90° phase shift clockwise is the γ-axis, the effect of output voltage distortion caused by the inverter appears prominently on the γ-axis.

FIG. 13 is a configuration diagram of the motor drive device of this embodiment. In this configuration, considering the relationship between the direction of the current vector and the influence of the output voltage distortion caused by the inverter, the pulsating current detector 116 in the configuration of the first embodiment (FIG. 1) is replaced with the pulsating current detector 116'. be. In this embodiment (FIG. 13), the configuration includes the torque pulsation compensator 109, but it may be replaced with the torque pulsation compensator 109' shown in the second embodiment.

FIG. 14 shows the configuration of the pulsating current detector 116'. The difference from the pulsating current detector 116 of Example 1 (FIG. 5) is that a current phase calculator 1400, a dq/γδ converter 1401, and an adder 1402 are added.

A current phase calculator 1400 calculates a current phase β "tan-1 (-Idc/Iqc)" based on the d-axis and q-axis detected currents Idc and Iqc. The dq/γδ converter 1401 calculates the following equation (8) based on the current phase β.

By the calculation of the equation (8), the current vector is separated into a γ-axis component in the non-energization direction and a δ-axis component in the conduction direction. The γ-axis detection current Iγc is multiplied by cos6θdc′ in the multiplier 1405 to generate the second component Ih2 of the current ripple through the LPF 502 . Similarly, the .delta.-axis detection current I.delta.c is multiplied by sin6.theta.dc' in the multiplication section 1406, and the first component Ih1 of the current pulsation is generated via the LPF 505.

The operation after the pulsating current detector 116' generates the first component Ih1 and the second component Ih2 of the current pulsation is the same as in the first and second embodiments.

An outdoor unit of an air conditioner according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 15 shows an example in which the motor drive device according to any one of the first through third embodiments is applied to a fan motor system mounted on an outdoor unit of an air conditioner.

The outdoor unit 1500 includes a fan motor drive device 1501 , a compressor motor drive device 1502 , a fan motor 1503 , a fan 1504 , a frame 1505 and a compressor device 1506 . The fan motor driving device 1501 is a motor driving device according to any one of the first to third embodiments described above.

The operation of the fan motor system in the outdoor unit 1500 will be described. AC power supply 1507 is connected to compressor motor drive 1502 . Compressor motor drive device 1502 rectifies supplied AC voltage VAC to DC voltage VDC to drive compressor device 1506 . At the same time, the compressor motor driving device 1502 also supplies the DC voltage VDC to the fan motor driving device 1501, and further outputs a motor speed command ωr*.

The fan motor driving device 1501 operates based on the input motor speed command ωr* and supplies a three-phase voltage to the fan motor 1503 . This drives the fan motor 1503 and rotates the connected fan 1504 . The above is the operation of the fan motor system.

In an outdoor unit of an air conditioner, it is common to mount an inexpensive computing device on the fan motor driving device 1501 in order to reduce costs. Further, in many cases, the fan motor 1503 is not provided with a position sensor. Even in such applications, torque pulsation suppression control can be realized by using the motor drive device according to the present invention as a fan motor drive device. As a result, vibration to the frame 1505 caused by the fan motor 1503 is reduced, and noise emitted from the outdoor unit 1500 can be reduced.

The motor driving device according to the present invention is very easy to apply because it does not require preliminary tests, adjustment work, and the like. Further, since the torque pulsation suppression control is autonomous, the present invention can be applied to existing equipment in which it is difficult to measure motor characteristics.

It should be noted that the motor drive device according to the embodiments of Examples 1 to 3 can also be used as a compressor motor drive device. In short, the present invention can be applied to any motor drive device having vector control as a basic configuration.

In addition, in the embodiments of the first to third embodiments, the position sensorless type motor driving device has been described as an example, but the present invention can also be applied to a motor driving device equipped with position sensors such as encoders, resolvers, and magnetic pole position sensors. can do. For example, the present invention can be applied to a configuration in which a position sensor is added to the motor 101 shown in FIGS.

1, 9 and 13, the deviation between the d-axis command current Id* and the d-axis detection current Idc and the deviation between the q-axis command current Iq* and the q-axis detection current Iqc The present invention can also be applied as a configuration including current feedback control based on.

In this case, the response band of the constructed current feedback control is designed to be sufficiently lower than the variation frequency of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter. As a result, the information contained in the d-axis and q-axis detection currents Idc and Iqc is the same as in the first to third embodiments, and appropriate operation according to the present invention is possible.

In Embodiments 1 to 3, the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter have been described as fluctuating in the 6th order cycle. Even in such a case, the present invention can be similarly applied.

Further, according to each embodiment of the present invention, the effects of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter are detected and compensated based on the d-axis and q-axis detection currents, which are one of the detection signals. It is a control that performs By using the detection signal instead of the command signal, the above control can be performed with high accuracy by minimizing the effects of modeling errors, calculation errors, and the like.

When a detection signal is used, there is concern about an increase in cost due to the addition of a sensor or the like, but most motor driving devices are equipped with a current sensor. That is, the present invention realizes torque pulsation suppression control that operates autonomously only with the existing sensor.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above embodiments have been described in detail to facilitate understanding of the present invention, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

DESCRIPTION OF SYMBOLS 100... Motor drive device 101... Permanent magnet synchronous motor (motor) 102... Command speed generation part 103... Control part 104... Power conversion circuit 105... Current sensor 106... Gain multiplication part 107... Command voltage calculation Part 108...LPF (low-pass filter) 109, 109'...torque ripple compensator 110, 110a, 110b...adder 111...dq/3-phase converter 112...dead time compensator 113, 113a, 113b , 113c... adder 114... rotor position detector 115... three-phase/dq converter 116, 116'... pulsating current detector 200... permanent magnet synchronous motor (dq coordinate model) 201a, 201b... adder Part 202a, 202b Adder 203, 204 Multiplyer 500 cos6θdc signal generator 503 sin6θdc signal generator 501, 504 Multiplyer 502, 505 LPF (low pass filter) 600 Integration Control unit 601 Addition unit 602 Initial value setting unit 603 sin6θdc signal generation unit 604, 606, 607, 608 Multiplication unit 605 cos6θdc signal generation unit 700 Integration control unit 701 Initial value Setting section 702 Addition section 703,705,707 Sign function section 704,706,708 Multiplication section 1000 Compensation voltage calculation section 1002 LPF (low pass filter) 1003, 1004, 1006, 1007 Multiplication section 1005, 1008 Addition section 1400 Current phase calculation section 1401 dq/γδ conversion section 1402 Addition section 1403 cos6θdc' signal generation section 1404 sin6θdc' signal generation section 1405, 1406 Multiplication unit 1500 Outdoor unit (unit) 1501 Fan motor drive device 1502 Compressor motor drive device 1503 Fan motor 1504 Fan 1505 Frame 1506 Compressor device 1507 Alternating current power supply, ωr motor speed, ωr* command speed (motor speed command), ω1c electrical angular velocity obtained by PLL, Vu*, Vv*, Vw* three-phase command voltage, Vdc*, Vqc* d-axis and q-axis command voltage, ΔVd*, ΔVq* ... d-axis and q-axis compensation command voltage, Vdc**, Vqc** ... d-axis and q-axis command voltage after compensation, ΔVu*, ΔVv*, ΔVw* ... three-phase Compensation command voltage, Vu**, Vv**, Vw**... three-phase compensation command voltage after compensation, Iu, Iv, Iw... three-phase detection current, Id, Iq... d-axis and q-axis voltages current, Idc, Iqc... d-axis and q-axis detection currents, Ih1 and Ih2... first and second components of current pulsation, θd... rotor position, θdc... estimated value of rotor position, Δθc... axis error , τm... motor torque, P... number of motor poles, R... winding resistance, Ld, Lq... d-axis and q-axis inductance, Ke... induced voltage coefficient, Kehd, Kehq... induced voltage coefficient on d-axis and q-axis Pulsation component (distortion component), Keh ... amplitude value of Kehd and Kehq, Keh* ... setting value of amplitude value Keh, ΔKeh ... adjustment value in the calculation of Keh*, Keh0 ... in the calculation of Keh* Initial value, Vtd... three-phase stationary coordinate component of output voltage distortion caused by inverter, Vtdd, Vtdq... d-axis and q-axis components of output voltage distortion caused by inverter, Vtd... amplitude value of Vtd, Vtd*... amplitude value Set value of Vtd, ΔVtd…Adjusted value in calculation of amplitude value Vtd*, Vtd0…Initial value in calculation of amplitude value Vtd*, ΔVd1*, ΔVd2*…First amplitude of d-axis compensation voltage and second amplitude (first d-axis compensation command voltage, second d-axis compensation command voltage), ΔVq1*, ΔVq2* … first amplitude and second amplitude of q-axis compensation voltage (first q-axis compensation command voltage , second q-axis compensation command voltage), Iγc, Iδc . . . γ-axis and .delta.-axis detection currents, β .

Claims (10)

a power conversion circuit that supplies power to the motor;
a control unit that controls the power conversion circuit;
a current sensor that detects a three-phase current supplied to the motor,
The control unit includes a command voltage calculation unit that calculates a command voltage that contributes to driving the motor;
a pulsating current detection unit that generates a first component and a second component by extracting the pulsating component of each component based on each component obtained by separating the three-phase detection current detected by the current sensor into mutually orthogonal components;
a torque ripple compensator that outputs a first compensation command voltage that compensates for torque ripple caused by the structure of the motor based on the first component;
a dead time compensation unit that outputs a second compensation command voltage that compensates for output voltage distortion caused by dead time of the power conversion circuit based on the second component,
A motor driving device, wherein the torque pulsation and the output voltage distortion are reduced by correcting the command voltage with the first compensating command voltage and the second compensating command voltage. The motor drive device according to claim 1,
The control unit has a three-phase/dq conversion unit that converts the three-phase detection current into a d-axis current and a q-axis current,
The mutually orthogonal components are a d-axis component and a q-axis component,
the first component is a pulsation component of one of the d-axis component and the q-axis component;
The motor drive device, wherein the second component is the pulsation component of the other of the d-axis component and the q-axis component. In the motor drive device according to claim 2,
The control unit has a rotor position detection unit that detects a rotor position of the motor,
The pulsating current detector multiplies the q-axis current by a sine wave signal or a cosine wave signal that fluctuates in order of 6n (where n is an integer equal to or greater than 1) according to the rotor position of the motor, thereby obtaining the first component. generates a signal containing information about
A motor drive comprising: generating a signal containing information of the second component by multiplying the d-axis current by a sine wave signal or a cosine wave signal that varies in 6n order according to the rotor position of the motor. Device. The motor drive device according to claim 1,
The control unit includes a three-phase/dq conversion unit that converts the three-phase detection current into a d-axis current and a q-axis current;
a rotor position detection unit that detects the rotor position of the motor;
the pulsating current detection unit, based on the d-axis current and the q-axis current, a current phase calculation unit that calculates a current phase corresponding to an angle between a current vector formed by these currents and the q-axis;
an addition unit that adds the rotor position of the motor and the current phase to generate a corrected rotor position;
dq for converting the d-axis current and the q-axis current into a δ-axis component facing the direction of the current vector and a γ-axis component having a 90° phase shift with respect to the δ-axis based on the current phase; /γδ conversion unit,
A signal containing information of the first component obtained by multiplying the current on the δ-axis by a sine wave signal or cosine wave signal that fluctuates in 6n order (n is an integer of 1 or more) according to the corrected rotor position to generate
A signal containing information on the second component is generated by multiplying the current on the γ-axis by a sine wave signal or a cosine wave signal that fluctuates in the order of 6n according to the corrected rotor position. motor drive. In the motor drive device according to claim 4,
The torque ripple compensator calculates a first parameter related to induced voltage distortion caused by the structure of the motor by integral control based on the first component,
A d-axis compensation command voltage and a q-axis compensation command voltage are calculated based on a sine wave signal or a cosine wave signal varying in 6nth order according to the first parameter, the electrical angular velocity of the motor, and the rotor position or the corrected rotor position. A motor drive device that generates a compensation command voltage. In the motor drive device according to claim 4,
The torque ripple compensator calculates a first parameter related to induced voltage distortion caused by the structure of the motor by integral control based on the first component,
Based on the first parameter, the q-axis current, the electrical angular velocity of the motor, and the rotor position or the corrected rotor position, d A motor driving device that generates an axis compensation command voltage and a q-axis compensation command voltage. The motor drive device according to claim 1,
The dead time compensation unit calculates a second parameter related to output voltage distortion caused by the dead time of the power conversion circuit by integral control based on the second component,
A motor driving device, wherein a three-phase compensation command voltage is generated based on the second parameter and information on the three-phase detected current. a permanent magnet synchronous motor;
a motor driving device for driving the permanent magnet synchronous motor;
a fan connected to the permanent magnet synchronous motor;
a frame for mounting the permanent magnet synchronous motor;
In an outdoor unit of an air conditioner comprising a compressor device system,
An outdoor unit for an air conditioner, wherein the motor driving device is the motor driving device according to any one of claims 1 to 7. detecting a three-phase current supplied to the motor, separating the detected three-phase detection current into mutually orthogonal components, and extracting the pulsation component of each component to generate a first component and a second component;
generating a first compensating command voltage that compensates for torque ripple caused by the structure of the motor based on the first component;
generating a second compensation command voltage that compensates for output voltage distortion caused by dead time of the power conversion circuit based on the second component;
A motor drive control method, wherein the torque pulsation and the output voltage distortion are reduced by correcting a command voltage that contributes to driving the motor with the first compensation command voltage and the second compensation command voltage. In the motor drive control method according to claim 9,
The mutually orthogonal components are a d-axis component and a q-axis component,
the first component is a pulsation component of one of the d-axis component and the q-axis component;
The motor drive control method, wherein the second component is the pulsation component of the other of the d-axis component and the q-axis component.

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