JP2017192200A - Motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device capable of driving a plurality of motors by a position sensorless system, and operating the plurality of motors by synchronizing rotation phases of the respective motors with one another.SOLUTION: A motor control device according to one embodiment comprises: a plurality of magnetic pole position estimation units that individually estimate magnetic pole positions of a plurality of motors; a vector controllers that individually performs vector control of the plurality of motors on the basis of the magnetic pole positions; and a phase synchronization controller that outputs a phase adjustment signal for correcting an input signal or an output signal of a speed controller included in the vector controllers corresponding to the other motors so that rotation phases of the other motors are synchronized with a rotation phase of one motor that becomes a reference among the plurality of motors.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a control device that synchronizes rotational phases of a plurality of motors.

  Conventionally, as a method of driving a permanent magnet synchronous motor using a plurality of inverters, for example, there is a position sensorless control device for a synchronous motor disclosed in Patent Document 1. In this prior art, a synchronous motor having multiple windings is a control target. In the multiplex winding, it is necessary to align the energization phases of the respective windings, and a plurality of connected inverters perform control with the energization phases aligned.

Japanese Patent No. 5527025

However, in the configuration of Patent Document 1, it is not possible to drive completely individual permanent magnet synchronous motors by position sensorless control and synchronously operate the rotational phases of the respective motors.
Therefore, a motor control device is provided that can drive a plurality of motors by a position sensorless method and can operate by synchronizing the rotation phases of the motors.

  According to the motor control device of the embodiment, a plurality of magnetic pole position estimation units that respectively estimate the magnetic pole positions of a plurality of motors, a vector control unit that performs vector control of each of the plurality of motors based on the magnetic pole positions, For correcting an input signal or an output signal of a speed control unit included in a vector control unit corresponding to the other motor so that the rotation phase of the other motor is synchronized with the rotation phase of one of the plurality of motors serving as a reference. A phase synchronization control unit that outputs a phase adjustment signal.

Functional block diagram showing the configuration of the motor control device according to the first embodiment Functional block diagram showing the configuration of the vector controller Functional block diagram showing the configuration of the position estimation unit Functional block diagram showing the configuration of the phase synchronization controller The figure which shows each waveform of the rotation electric angle of each motor, its difference value, and a slave side motor current at the time of performing phase synchronous control when rotating two motors at constant speed Functional block diagram showing the configuration of the phase synchronization control unit according to the second embodiment Functional block diagram showing the configuration of the phase synchronization control unit according to the third embodiment The figure explaining MTPA control

(First embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a functional block diagram showing the configuration of the motor control device. In the present embodiment, a configuration for controlling the rotational phases of two motors will be described, but the present invention can also be applied to a configuration for controlling three or more motors. In the present embodiment, when controlling the rotational phases of a plurality of motors, the motor driven with the reference rotational phase is the master side motor, and any phase difference (zero phase difference if perfect synchronization) is used as a reference. ) Is defined as the slave side motor. As described above, there can be any number of slave side motors.

The speed command value ω _Ref is commanded from a _host system that drives the motor, for example, a system such as an air conditioner, and is input to the control unit 1. The control unit 1 includes a master side vector control unit 2M and a slave side vector control unit 2S, and the speed command value speed command value ω _Ref is directly input to the master side vector control unit 2M as ω _Ref1 . On the other hand, as a result of the speed command value speed command value ω _Ref being input to the phase synchronization control unit 3 together with the synchronization angle command θ _{Ref and} controlled, the slave side vector control unit 2S generates a new speed command value ω _Ref2. Is input.

  In each of the vector control units 2M and 2S, PWM signals for the master side inverter 4M and the slave side inverter 4S are generated and output based on the speed and current detected for the corresponding motor. These inverters 4M and 4S are driven by applying an AC voltage to the master side motor 5M and the slave side motor 5S, respectively, according to the input PWM signal. The motor 5 is a permanent magnet synchronous motor.

FIG. 2 shows the configuration of the vector control unit 2. This configuration is common to the master side and the slave side. The three-phase / two-phase conversion unit 11 uses a three-phase current detected for the motor 5 via a current sensor (not shown) or a current detection resistor arranged in the inverter 4 in the dq axis coordinates used for vector control. The current is converted to Id and Iq. Speed control unit 12 generates the q-axis current command _{Iq_ Ref} from the estimated velocity omega _c output from the position estimator 13 and the input speed command ω _{Ref (1,2)} output. Field control unit 14 weakening the inverter output voltage Vd, so Vq does not exceed the DC voltage _{V DC,} generates and outputs a field weakening current d-axis current command _{id_ Ref.}

Current controller 15, d-axis input current command _{id_ Ref} q-axis, _{Iq_ Ref} and current Id, d from Iq, the q-axis voltage command Vd, and generates and outputs Vq. The two-phase / three-phase converter 16 converts the dq axis voltage commands Vq, Vd into three-phase motor voltages Vu, Vv, Vw. The modulation control unit 17 generates PWM signals U ±, V ±, W ± for six elements energized to the inverter 4 from the three-phase motor voltages Vu, Vv, Vw and the DC voltage _VDC .

The position estimation unit 13 obtains an estimated speed ω _c , an estimated rotational position θ _c and a position estimation error Δθ of the motor 5 from the d-axis and q-axis currents Id and Iq and the d-axis voltage Vd. FIG. 3 shows the configuration of the position estimation unit 13. The induced voltage calculator 18 calculates a d-axis induced voltage Ed from the currents Id and Iq and the d-axis voltage Vd, and a PI (Product-Integral) calculator 19 performs a PI calculation on the d-axis induced voltage Ed and performs a subtractor. 20 The subtractor 20 obtains the estimated speed ω _c of the motor 5 by subtracting the PI calculation result from the speed command value ω _Ref . Further, the estimated rotational position θ _c is obtained by integrating the estimated speed ω _c by the integrator 21. Further, the d-axis induced voltage Ed is divided by the product of the estimated speed ω _c and the armature flux linkage φ by the divider 22 to obtain the position estimation error Δθ.

Next, the configuration of the phase synchronization control unit 3 will be described with reference to FIG. The phase synchronization control unit 3 receives a synchronization angle command θ _Ref that is a rotation phase difference command between the two motors 5M and 5S. The subtracter 23 inputs a deviation sin θ _{dev obtained} by subtracting the phase difference θ _dev2 between the two motors 5M and 5S from the synchronization angle command θ _Ref to the controller 24. Here, the controller 24 uses a proportional device and multiplies the deviation sin θ _dev by a proportional coefficient C (s) = K _{p_APR} and outputs the result. The output signal of the controller 24 corresponds to a phase adjustment signal, and the adder 25 adds the phase adjustment signal and the master side speed command value ω _Ref1 to obtain the slave side speed command value ω _Ref2. Yes.

The respective speed command values ω _Ref1 and ω _Ref2 are input to the respective vector control units 2M and 2S to be speed controlled as described above, and the inverters 4M and 4S apply PWM signals to the motors 5M and 5S, respectively. As a result, the motors 5M and 5S rotate at the speeds ω ₁ and ω ₂ , respectively, and their rotational positions become θ ₁ and θ ₂ . In FIG. 4, the vector control unit 2 is divided into a speed control unit 12 and a vector control unit 2 ′ indicating other functional blocks.

Since the actual rotational position theta _1, theta ₂ can not be detected directly, seeking rotational phase difference theta _dev1 therebetween by subtracting the estimated rotational position theta _c2 than the estimated rotational position theta _c1 by the subtracter 26. Further, the difference between the position estimation errors Δθ ₁ and Δθ ₂ calculated by the position estimation unit 13 is calculated by the subtractor 27 and is subtracted from the rotation phase difference θ _dev1 by the subtractor 28, so that the rotational position considering the estimation error is obtained. The phase difference θ _dev2 is obtained and fed back to the subtracter 23.

Next, the operation of this embodiment will be described. Here, a case where the synchronization angle command θ _Ref is zero is illustrated. For example, when the slave-side motor 5S rotates with a delay phase with respect to the master-side motor 5M, if the difference between the estimated rotational positions θ _c1 and θ _c2 of the two motors 5M and 5S is obtained and fed back, the speed command of the motor 5S The value ω _Ref2 becomes larger than the speed command value ω _{Ref1 of the} motor 5M by the amount to which the output signal of the controller 24 is added. As a result, the speed of the motor 5S becomes faster than that of the motor 5M, and the rotation position θ ₂ and the estimated rotation position θ _c2 that are integral values thereof also advance, so that the phase error is reduced.

Even in this state, the phase synchronous drive between the two motors 5M and 5S is achieved to some extent. However, if the estimated rotational position theta _c with respect to the actual rotational position theta of the motor 5 has an error, the synchronization phase difference occurs. Therefore, as described above, the position estimation errors Δθ ₁ and Δθ ₂ of the two motors 5M and 5S are calculated by the respective position estimation units 13, and the difference between them is calculated and added to the phase difference θ _dev1 to obtain the position estimation error. High-accuracy phase synchronization control is performed by calculating the synchronous phase difference θ _dev2 in consideration.

  FIG. 5 shows the rotational electrical angles of the motors 5M and 5S, the difference value (phase error), and the slave motor 5S when the phase synchronization control is performed when the two motors 5M and 5S are rotated at the same speed. Current is shown. It can be seen that after the phase synchronization control is started, the rotation angles of the motors 5M and 5S are synchronized, and the phase error converges to zero.

As described above, according to the present embodiment, the magnetic pole positions θ _c1 and θ _c2 of the motors 5M and 5S are estimated by the magnetic pole position estimation units 13M and 13S, and the phase synchronization control unit 3 rotates the rotational position of the motor 5M serving as a reference. A phase adjustment signal for synchronizing the rotational position θ _c2 of the motor 5S with θ _c1 is output, and the rotational speed command ω _Ref1 is corrected. As a result, vibrations and the like associated with the operation of the two motors 5M and 5S are reduced, so that noise, vibrations and the like that are problematic as a product such as an air conditioner can be reduced.

Then, the phase synchronization control unit 3 performs phase based on the difference value θ _dev1 between the magnetic pole positions θ _c1 and θ _c2 of the motors M and 5S detected by the magnetic pole position estimation unit 13 and the magnetic pole position estimation errors Δθ ₁ and Δθ _2. Synchronous control. Thus, the estimated rotational position theta _c even if it contains errors [Delta] [theta], it is possible to perform highly accurate phase synchronization control.

(Second Embodiment)
FIG. 6 shows a second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Different parts will be described. In the control unit 3 of the first embodiment, the adder 25 is on the input side of the speed control unit 12S, and the output signal of the computing unit 24 is added to the speed command value ω _Ref1 on the master side. In contrast, the control unit 31 of the second embodiment, the adder 25 is on the output side of the speed control unit 12S, adds the output signal of the arithmetic unit 24 is the output of the speed control unit 12S to _{Iq_ Ref2.} And what added the adder 25 to the vector control part 2S of 1st Embodiment comprises the vector control part 32S of 2nd Embodiment.

  The configuration shown in FIG. 6 is based on the assumption that the motor 5 to be controlled is a surface magnet type synchronous motor (SPMSM). In this case, since the output torque of the motor 5 is controlled only by the q-axis current, the output of the vector control unit 2S is the q-axis current, and the output of the phase synchronization control unit 31 is also added to the q-axis current.

  According to the second embodiment configured as described above, since the output signal of the speed control unit 12S is corrected by the output signal of the computing unit 24, this corresponds to the case where the motors 5M and 5S are surface magnet type synchronous motors. Thus, optimal phase synchronization control can be performed.

(Third embodiment)
The configuration of the third embodiment shown in FIG. 7 is based on the premise that the motor 5 to be controlled is an embedded permanent magnet synchronous motor (IPMSM). In this case, the output torque of the motor 5 is converted to the d-axis current. And q-axis current. Therefore, the control unit 33 of the third embodiment includes vector control units 34M and 34S.

In the vector control unit 34, in addition to the configuration of the second embodiment, an MTPA (Max Torque Per Ampere) control unit 35 is disposed in the next stage of the speed control unit 12. Then, the current command value I _Ref is allocated to the optimum current commands Id_ _Ref and Iq_ _Ref for the respective d-axis and q-axis by the MTPA algorithm executed by the control unit 35. Further, the functional block 34M ′ shown in the figure corresponds to the remaining functional blocks excluding the speed controller 12M and the MTPA controller 35M in the vector controller 34M. The functional block 34S ′ corresponds to the remaining functional blocks excluding the speed control unit 12S, the adder 25, and the MTPA control unit 3M in the vector control unit 34S.

  FIG. 8 relates to the MTPA control. The horizontal axis represents the d-axis current Id, and the vertical axis represents the q-axis current Iq. The three constant torque curves shown in the figure are obtained by connecting pairs of possible d-axis and q-axis currents Id and Iq to the three types of torques T1, T2 and T3 output from the motor 5. For example, when considering three types shown by broken lines as current pairs when torque T2 is applied, the current pair with the smallest current, that is, the current pair with the short distance from the origin is Iq = 4.5A, Id = -4.3A. . When these are connected for each torque, the movement shown on the MTPA control line shown in the figure is obtained. In other words, MTPA is an algorithm for selecting a combination that minimizes current when outputting a certain torque.

The MTPA control unit 35 holds a map as shown in FIG. 8 as table data in, for example, a memory, and the d-axis and q-axis currents Id and Iq that minimize the current corresponding to the desired output torque of the motor 5 are stored. Select a combination.
According to the third embodiment configured as described above, since the current command I _Ref of the motor 5 is controlled by the output signal of the computing unit 24, this corresponds to the case where the motors 5M and 5S are embedded magnet type synchronous motors. Thus, optimal phase synchronization control can be performed.

(Other embodiments)
The synchronization angle command θ _Ref is not limited to zero, but may be set to an appropriate angle according to individual specifications.
The present invention is not limited to an air conditioner and can be applied to any system that synchronously controls the rotation phases of a plurality of motors.
Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1 is a control unit, 2 is a vector control unit, 3 is a phase adjustment unit, 4 is an inverter, 5 is a motor, 31 is a phase adjustment unit, and 33 is an MTPA control unit.

Claims (4)

A plurality of magnetic pole position estimators for respectively estimating the magnetic pole positions of the plurality of motors;
Based on the magnetic pole position, a vector control unit that performs vector control on each of the plurality of motors,
In order to correct an input signal or an output signal of a speed control unit included in a vector control unit corresponding to the other motor so that the rotation phase of the other motor is synchronized with the rotation phase of one of the plurality of motors serving as a reference. And a phase synchronization control unit that outputs the phase adjustment signal.   The motor control device according to claim 1, wherein a rotation speed command that is the input signal is corrected by the phase adjustment signal.   The motor control device according to claim 1, wherein the current command that is the output signal is corrected by the phase adjustment signal.   The said phase-synchronization control part outputs a phase adjustment signal based on the difference value and magnetic pole position estimation error of the magnetic pole position of each motor detected by the said magnetic pole position estimation part. Motor control device.

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