JP2008306801A - Controller of permanent magnet motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to output torque stably by reducing torque ripples without requiring prior measurement of the torque ripples when suppressing the torque ripples of a permanent magnet motor and even if a frequency of torque ripples which occurs to an output shaft is high. <P>SOLUTION: When even number of rotors of permanent magnet motors whose characteristics are the same are connected on the same shaft, the rotors are mounted by displacing a mounting angle so as to cause the torque ripples generated in each permanent magnet motor to have a phase difference canceling each other. Control amplifiers are installed which perform the torque control of each permanent magnet motor individually to distribute a torque command equally to each control amplifier. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for suppressing torque ripple of a permanent magnet motor using a permanent magnet for a rotor portion of a motor.

  A conventional torque ripple reduction method for a permanent magnet motor is shown in FIG. 3 and will be described with reference to FIG.

  A three-phase balanced AC voltage is applied to the permanent magnet motor 1 by the power converter 111, and a three-phase balanced current flows.

  The current value flowing in each phase is determined by the three-phase-dq converter 109 based on the rotor position information of the position detector 103 attached to the permanent magnet motor 1. It is converted into current iq.

  The q-axis current controller 107 receives a deviation between the q-axis current command 105 and the q-axis current iq, and outputs a q-axis voltage command vqref through the PI adjuster so that the deviation becomes zero.

  The d-axis current controller 108 receives the deviation between the d-axis current command 106 and the d-axis current id, and outputs a d-axis voltage command vdref through the PI adjuster so that the deviation becomes zero.

  The d-axis voltage command vdref and the q-axis voltage command vqref are balanced three-phase AC voltage commands vref, vvref, based on the rotor position information of the position detector 103 attached to the permanent magnet motor 1 by the dq-three-phase converter 110. It is converted into vwref and given to the power converter 111.

  The d-axis current command 106 and the q-axis current command 105 are generated by the current command generator 104 based on the torque command from the torque command generator 9.

  With this configuration and current control, the current flowing through the permanent magnet motor 1 is controlled in a sine wave shape under the condition that the torque command is constant, but when the field magnetic flux is not a sine wave, as shown in FIG. In particular, it is known that a torque ripple having a frequency six times the rotational frequency is generated.

  In particular, when the winding structure of the stator is a concentrated winding structure, a harmonic component appears in the primary magnetic flux generated by the primary winding, and a larger torque ripple is generated.

  In Patent Document 1, as a means for suppressing such torque ripple, a damping signal whose phase is set by an artificial operation so as to be opposite in phase to the torque ripple is generated, and this damping signal and the q-axis current command value are set as follows. By multiplying the multiplied value by a constant that is changed manually, a current command set to have the same amplitude as the torque ripple is generated by the pulsation suppression current generator 101 and added to the q-axis current command 105 to generate torque ripple. I try to counter it.

  In Patent Document 2, the number of poles of the permanent magnet motor 1, the rotor position information of the position detector 103, and the average value of the difference between the upper limit and the lower limit of torque ripple variation are stored in advance in a memory. The phase data of the torque ripple is calculated from the rotor position information of the detector 103 and the number of poles of the permanent magnet motor, the average value of the difference between the upper limit and the lower limit of the fluctuation of the torque ripple is used as the amplitude, and the phase data The torque command corrector 102 calculates a torque correction value by a sine wave function using.

  Instead of the pulsation suppression current generator 101, the torque ripple is canceled by adding the output of the torque command corrector 102 to the torque command of the torque command generator 9.

  In any torque ripple suppression means, the current command and torque command for suppressing the torque ripple are determined by measuring the generated torque ripple and repeating trial and error.

In addition, the higher the motor rotation speed, the higher the torque ripple frequency. In order to suppress high-frequency torque ripple, it is necessary to speed up the response of current control and torque control. Required.
JP 2001-352798 A Japanese Patent No. 3719426

  The problem to be solved is that the determination of the current command and torque command to suppress the torque ripple requires measurement of the generated torque ripple, and trial and error must be repeated, and the motor is driven at a high frequency. In this case, it is difficult to correct the torque ripple due to the calculation cycle of the calculation device.

  According to the first aspect of the present invention, at least two or more of the rotors of a permanent magnet motor using a permanent magnet for the rotor portion of the motor are connected on the same shaft, and each of the rotors has one stator. In the permanent magnet motor control device that individually controls the torque of the magnet motor with a control amplifier, the mounting angles of the rotors are shifted on the shaft so as to cancel the torque ripples generated in the permanent magnet motors. It is characterized by being attached.

  Further, in claim 2, the characteristics of the permanent magnet motors connected to the same shaft in claim 1 are the same characteristics, the number of the permanent magnet motors is an even number, and the rotors of the permanent magnet motor are two sets as one set. The mounting angle of one rotor and the other second rotor to the shaft is shifted by 30 degrees in electrical angle and mounted on the shaft, and all torque commands given to individual control amplifiers are equally distributed. It is characterized by.

  There is no need to generate a current command or torque command to suppress torque ripple, and there is no need to increase the speed of the arithmetic unit to suppress torque ripple even when the motor is driven at high frequency. Torque ripple output to the outside can be effectively suppressed, and the permanent magnet motor can be controlled to output stable torque.

  Achieves the purpose of suppressing torque ripple and outputting stable torque to the outside through the shaft without the need to generate a current command or torque command to suppress torque ripple, and without increasing the load on the arithmetic unit did.

  FIG. 1 shows an embodiment of claim 2 of the present invention, and the present invention will be described in detail based on FIG.

  FIG. 1 shows an example in which the number of permanent magnet motors connected on the same shaft is two.

  The rotor 3 of the permanent magnet motor 1 and the rotor 4 of the permanent magnet motor 2 having the same characteristics as the permanent magnet motor 1 are connected via a shaft 5.

  At this time, the positions of the permanent magnets 61 to 64 of the rotor 4 are shifted from the positions of the permanent magnets 61 to 64 of the rotor 3 by θ, and the stator 7 of the permanent magnet motor 1 and the stator 8 of the permanent magnet motor 2 are the same. Install it at an angle.

  The torque command of the torque command generator 9 is distributed to the control amplifier 11 and the control amplifier 12 by the torque command distributor 10, and the permanent magnet motor 1 is torque-controlled by the control amplifier 11 and the permanent magnet motor 2 is torque-controlled by the control amplifier 12, respectively. .

  When the permanent magnet motor 1 is operated with a constant torque command, a torque ripple having a cycle 6 times as long as one electrical angle cycle is generated as shown in FIG. The torque ripple generated by the permanent magnet motor 1 can be canceled if the torque ripple having the same amplitude and the opposite phase can be generated.

  Since one cycle of torque ripple is 60 degrees in electrical angle, the permanent magnet motor 2 can generate torque ripples of opposite phase with respect to the positions of the permanent magnets 61 to 64 of the rotor 3. The position of ~ 64 should just be arrange | positioned in the position which shifted | deviated 30 degree | times by the electrical angle.

  That is, if the number of poles of the permanent magnet motor is P, the rotor 4 may be attached to the shaft 5 with a mechanical angle shifted from the rotor 3 by θ represented by the equation (1).

  In order to make the amplitudes of the torque ripples equal, the torque command generator 10 can evenly distribute the torque command of the torque command generator 9 so that the same torque command is input to the control amplifier 11 and the control amplifier 12. Good.

  FIG. 2 applies the second aspect of the present invention, and the position of the permanent magnets 61 to 64 of the rotor 4 is attached to a position shifted by 30 degrees in electrical angle with respect to the position of the permanent magnets 61 to 64 of the rotor 3. 11 and the torque ripple generated by the permanent magnet motor 1 and the permanent magnet motor 2 when the torque command to the control amplifier 12 is evenly distributed, and the shaft that combines the torque ripple of the permanent magnet motor 1 and the torque ripple of the permanent magnet motor 2. The torque transmitted to 5 is shown.

  Since the torque ripple generated by the permanent magnet motor 2 shown in FIG. 2B has the same amplitude and the opposite phase to the torque ripple generated by the permanent magnet motor 1 shown in FIG. The torque transmitted to the shaft 5 is canceled and no torque ripple occurs as shown in FIG.

  In the case of driving at a high frequency where the torque ripple period is shortened by canceling the torque ripple by arranging mechanical permanent magnets instead of the control method by superimposing the torque ripple suppression value on the torque command or current command. Also, the occurrence of torque ripple can be suppressed.

  Since the torque ripple and cogging torque generated per one permanent magnet motor can be offset and a stable torque output can be provided through the shaft of the permanent magnet motor, there is a great industrial applicability.

It is the figure which showed the structure of Claim 2. (Example) The operation | movement waveform at the time of applying Claim 2 is shown. (Example) It is the block diagram which showed the structure of background art. The operation | movement waveform at the time of applying background art is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Permanent magnet motor 2 Permanent magnet motor 3 Rotor 4 Rotor 5 Shaft 61 Permanent magnet 62 Permanent magnet 63 Permanent magnet 64 Permanent magnet 7 Stator 8 Stator 9 Torque command generator 10 Torque command distributor 11 Control amplifier 12 Control amplifier 101 Pulsation suppression current Generator 102 Torque command corrector 103 Position detector 104 Current command generator 105 q-axis current command 106 d-axis current command 107 q-axis current controller 108 d-axis current controller 109 three-phase-dq converter 110 dq-three-phase Converter 111 Power converter

Claims (2)

  At least two rotors of a permanent magnet motor using permanent magnets for the rotor portion of the motor are connected on the same shaft, and each of the permanent magnet motors having one stator per one rotor is individually connected. A control apparatus for a permanent magnet motor, wherein the torque is controlled by a control amplifier, wherein the mounting angle of each rotor is shifted and mounted on the shaft.   The characteristics of the permanent magnet motors connected to the same shaft are the same, the number of the permanent magnet motors is an even number, and the rotors of the permanent magnet motors are a set of two, and the first rotor and the other second The mounting angle of the rotor to the shaft is shifted on the shaft by an electrical angle of 30 degrees, and the torque commands given to the individual control amplifiers are all equally distributed. Control device for permanent magnet motor.

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