JP2009022091A - Device for monitoring demagnetization of permanent magnet in permanent magnet synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for monitoring the demagnetization of a permanent magnet in a permanent magnet synchronous motor, which can monitor the degree of demagnetization of the permanent magnet of the permanent magnet motor. <P>SOLUTION: This device for monitoring the demagnetization of the permanent magnet in the permanent magnet synchronous motor is equipped with a coasting operation detector 35 which detects the coasting operation state of the permanent magnet synchronous motor 1, an induced voltage detector 28 which detects the induced voltage by the permanent magnet in the no-load operation state of the permanent magnet synchronous motor, a demagnetization deciding part 35 which compares the detected value of the induced voltage by the permanent magnet in a no-load state with a specified reference value DMlmt and decides that the presence of demagnetization in the permanent magnet when the detected value DMr of the induced voltage in the no-load state falls below the reference value, and a monitor 36 which presents a demagnetization alarm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a permanent magnet demagnetization monitoring device for a permanent magnet synchronous motor that monitors a demagnetization state of a permanent magnet incorporated in a rotor of the permanent magnet synchronous motor.

  Permanent magnet synchronous motors embed a permanent magnet in the rotor core, and synchronize the rotor core using the force that the armature coil attracts the rotor core by the armature magnetic flux and the force that the armature coil attracts the permanent magnet. It is a synchronous motor provided with the principle of rotating.

  In such a permanent magnet synchronous motor, it is inevitable that the permanent magnet is demagnetized over time. In particular, the degree of demagnetization increases when the device becomes hot during operation and the permanent magnet is also heated. When the permanent magnet is demagnetized, the above-described armature coil has a reduced force for attracting the permanent magnet, and the desired torque cannot be obtained. Therefore, when the degree of demagnetization increases, it is re-magnetized or replaced. Maintenance is required.

However, conventionally, techniques for suppressing the demagnetization of the permanent magnet of the permanent magnet synchronous motor are known from JP-A-11-89197 (Patent Document 1) and JP-A-11-146588 (Patent Document 2). In addition, a permanent magnet synchronous motor having a structure capable of preventing demagnetization of the permanent magnet is known from Japanese Patent Application Laid-Open No. 2004-144026 (Patent Document 3), and an alarm is provided by monitoring the degree of demagnetization of the permanent magnet. The technology to output is not known.
JP 11-89197 A JP 11-146588 A JP 2004-144026 A

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a permanent magnet demagnetization monitoring device for a permanent magnet synchronous motor that can monitor the degree of demagnetization of the permanent magnet of the permanent magnet synchronous motor. And

  The present invention includes a coasting operation detection unit that detects a coasting operation state of a permanent magnet synchronous motor, an induced voltage detection unit that detects an induced voltage by a permanent magnet in a no-load operation state of the permanent magnet synchronous motor, and the no load Demagnetization of the permanent magnet is detected when the detected value of the induced voltage by the permanent magnet in a state is compared with a predetermined reference value and the induced voltage detected value in the no-load state falls below the reference value A permanent magnet demagnetization monitoring device for a permanent magnet synchronous motor including an occurrence determination unit.

  According to the permanent magnet demagnetization monitoring device of the permanent magnet synchronous motor of the present invention, the induced voltage by the permanent magnet in the no-load operation state of the permanent magnet synchronous motor is detected, and the induced voltage by the permanent magnet in the no-load state is detected. By comparing the value with a predetermined reference value and determining that demagnetization has occurred in the permanent magnet when the value falls below this reference value, demagnetization of the permanent magnet in the permanent magnet synchronous motor can be monitored.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) A permanent magnet synchronous motor control apparatus according to a first embodiment of the present invention will be described.

  As shown in FIG. 1, the main circuit for rotationally driving the permanent magnet synchronous motor (PMSM) 1 includes a pantograph 11 that takes in power from an overhead wire or a DC power supply of the third rail 10, a high-speed circuit breaker 12, a filter reactor 13, a filter The capacitor 14, the VVVF inverter 15, and the permanent magnet synchronous motor 1 driven by the VVVF inverter 15. A motor control unit 16 that gates the VVVF inverter 15 based on the motor voltage and the motor current, a current detector 17 that detects the motor currents Iu and Iw, and a resolver 18 that detects the rotational phase angle θr of the permanent magnet synchronous motor 1. The DC voltage detector 19 for detecting the DC voltage of the VVVF inverter 15 is provided.

  The motor control unit 16 executes a predetermined calculation process using the DC voltage Vdc of the VVVF inverter 15, the motor current detection values Iu and Iw, the rotation phase angle θr, and the input torque command TqRef, and sets the motor rotation speed range. Accordingly, a corresponding gate signal is output to the VVVF inverter 15 in order to perform constant torque control and constant output control of the permanent magnet synchronous motor 1.

  As shown in FIG. 2, the motor control unit 16 includes an optimal current phase angle calculation unit 20 that calculates an optimal current phase angle with respect to the torque command TqRef, adders 21, 22, 23, PI calculation units 24 and 25, and three current phases. It comprises a -dq converter 26, a voltage dq-3 phase converter 27, a terminal voltage calculator 28, a voltage command calculator 29, an adder 30, and a PI calculator 31. Here, the optimum phase angle current control unit 41 is configured by the optimum current phase angle calculation unit 20, the adders 21, 22 and 23, and the PI calculation units 24 and 25. Further, the terminal voltage calculation unit 28, the voltage command calculation unit 29, the adder 30, and the PI calculation unit 31 constitute a weakening magnetic flux control unit 42.

  Furthermore, the permanent magnet synchronous motor control device of the present embodiment is characterized in that the motor rotation speed S and the induced voltage V during coasting operation are based on the output V1 of the terminal voltage calculation unit 28 (referred to as motor voltage Vm). 3, the demagnetization limit curve DMlmt as shown in FIG. 3 is referred to, and when the induced voltage V is lower than the curve DMlmt, it is determined that demagnetization has occurred, and the demagnetization alarm is displayed on the cab monitor 36. Is displayed, and a demagnetization determination unit 35 that outputs a warning sound is provided.

  As shown in FIG. 4, the permanent magnet synchronous motor 1 is controlled by the motor control unit 16 until the rotational speed reaches the rated speed Rf, and the constant torque control is performed after the rotational speed reaches the rated speed Rf. Take control. In this constant torque control, Iq constant current control is performed at an optimum phase angle. In the constant output control, a flux weakening control is performed in which the motor voltage Vm is controlled to the inverter limit voltage Vlmt at a constant level by flowing a current ΔId in a direction that cancels the permanent magnet magnetic flux.

  In the optimum phase angle current control unit 41, the optimum current phase angle calculation unit 20 calculates an optimum current phase angle with respect to the torque command QRef. Then, the adder 21 adds the d-axis current command control value ΔIdRef of the magnetic flux weakening control unit 42 to output the d-axis current command IdRef. On the other hand, the q-axis current command IqRef is output from the optimum current phase angle calculation unit 20. The adders 22 and 23 compare the d-axis current command IdRef and the q-axis current command IqRef with the actual d-axis current Id and the actual q-axis current Iq. Calculated and output as current commands Vd and Vq.

  The resolver 18 that detects the rotational phase angle θr of the permanent magnet synchronous motor 17 inputs the rotational phase angle θr to the current three-phase-dq converter 26. The current three-phase-dq converter 26 converts the three-phase motor currents Iu and Iw detected by the motor current detector 17 into the actual d-axis current Id and the actual q-axis current Iq by using the rotational phase angle θr, and the optimum current. It outputs to the adders 22 and 23 of the phase angle control part 41, and is compared with the above-mentioned d-axis current command IdRef and q-axis current command IqRef.

  The voltage commands Vd, Vq from the optimum current phase angle control unit 41 are converted into three-phase voltage commands Vu, Vv, Vw by using the rotational phase angle θr from the resolver 18 in the voltage dq-3 phase converter 27, This is input to the VVVF inverter 15 as a voltage command. The VVVF inverter 15 converts DC power into three-phase motor power corresponding to the input voltage commands Vu, Vv, and Vw, and outputs it to the permanent magnet synchronous motor 1 for rotational driving.

  In the flux weakening control unit 42, the voltage command calculation unit 29 calculates and outputs the voltage command V1Ref based on the DC voltage Vdc from the DC voltage detector 19. The terminal voltage calculation unit 28 calculates and outputs the motor voltage V1 based on the voltage commands Vd and Vq from the optimum phase angle current control unit 41. The adder 30 compares the voltage command V1Ref and the terminal voltage V1, and performs a PI calculation on the difference value by the PI calculator 31 to obtain a d-axis weakening current ΔIdRef to adder of the optimum phase angle current control unit 41. To 21. Thus, when the motor speed is in the constant output control range, a current obtained by subtracting the current ΔId in the direction to cancel the permanent magnet magnetic flux from the optimum phase angle current command IdRef is given to the optimum phase angle current control unit 41 as a d-axis current command, The optimum phase angle current control unit 41 is caused to perform the flux weakening control in order to control the motor voltage Vm to a constant voltage of the inverter limit voltage Vlmt.

  Next, the demagnetization determination process of the permanent magnet of the permanent magnet synchronous motor 1 by the demagnetization determination unit 35 will be described. In the state where the permanent magnet embedded in the rotor core of the permanent magnet synchronous motor 1 is healthy, the motor speed S and the motor voltage Vm in the speed-voltage characteristic graph of FIG. Causes an induced voltage in the characteristic curve DMo in the healthy state. However, when the demagnetization proceeds, the motor voltage Vm decreases when the motor speed S is the same. Therefore, a permissible limit characteristic curve DMlmt in which a desired torque characteristic cannot be obtained as a permanent magnet synchronous motor is used as a reference curve, and the relationship between the motor voltage Vm and the rotation speed S in the coasting state is lower than the permissible limit characteristic curve DMlmt. When the curve DMr is obtained, the demagnetization determination unit 35 determines that demagnetization has occurred and outputs a demagnetization warning to the monitor 36 to notify the driver or engineer.

  Thereby, according to the permanent magnet synchronous motor control device of the present embodiment, the demagnetization of the permanent magnet embedded in the rotor core of the permanent magnet synchronous motor 1 is automatically determined and the driver or the Can inform the technician.

  (Second Embodiment) A permanent magnet motor synchronous motor control apparatus according to a second embodiment of the present invention will be described.

  As shown in FIG. 5, the second embodiment is characterized in that the demagnetization determination unit 35 </ b> A detects the determination of the permanent magnet demagnetization during the coasting operation of the permanent magnet synchronous motor 1 and the detection of the motor voltage Vm and the resolver 18. The relationship between the rotational speed S and the voltage speed characteristic is obtained directly, and compared with the allowable limit characteristic curve DMlmt in the voltage speed characteristic graph shown in FIG. , The demagnetization determination of the permanent magnet is performed and output to the monitor 36.

  In the present embodiment, the main circuit configuration is the same as that of the first embodiment shown in FIG. In the case of the present embodiment, a motor voltage detector 37 for detecting the motor voltage is installed on the AC path connected from the VVVF inverter 15 to the permanent magnet synchronous motor 1. The demagnetization determination unit 35 </ b> A is configured to input the motor voltage detection value of the motor voltage detector 37 together with the torque command and the output of the resolver 18. In FIG. 5, the same reference numerals are given to the components common to the first embodiment shown in FIGS. 1 and 3.

  Next, the operation of the permanent magnet synchronous motor control device of the present embodiment will be described. Also in the present embodiment, the gate control of the VVVF inverter 15 by the motor control unit 16A and the drive control operation of the permanent magnet synchronous motor 1 are the same as in the first embodiment.

  In the present embodiment, the demagnetization determination unit 35A executes the demagnetization determination of the permanent magnet as follows and outputs a demagnetization alarm to the monitor 36. The coasting operation state is determined from the torque command, and in the coasting operation state, the voltage detected by the voltage detector 37 is taken in as the motor voltage Vm, and the rotation speed signal S is taken in from the resolver 18, and the voltage speed of this Vm-S The characteristic is compared with the allowable limit characteristic curve DMlmt in the voltage speed characteristic graph of FIG. As in the first embodiment, the relationship between the motor voltage Vm and the rotational speed S in the coasting operation state, that is, the speed voltage characteristic is lower than the allowable limit characteristic curve DMlmt, and the curve DMr is obtained. When this happens, the demagnetization determination unit 35A determines that demagnetization has occurred, outputs a demagnetization warning to the monitor 36, and notifies the driver and technician.

  According to the present embodiment, it is possible to perform permanent magnet demagnetization determination and alarm output of the permanent magnet synchronous motor 1 by a system independent of the motor control unit 16A that performs complex arithmetic processing and gate-controls the VVVF inverter 15. Therefore, the demagnetization determination function can be easily added to an existing device in a so-called retrospective manner.

The circuit diagram of the main circuit structure controlled by the permanent magnet synchronous motor control apparatus of the 1st Embodiment of this invention. The block diagram of the motor control part in the said 1st Embodiment. The voltage speed characteristic graph of the permanent-magnet synchronous motor utilized in the said embodiment. The graph which shows the relationship between the constant torque control of the permanent magnet synchronous motor by the electric motor control apparatus of the said embodiment, constant output control operation | movement, and a motor speed. The block diagram of the permanent-magnet synchronous motor control apparatus of the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Permanent magnet synchronous motor 15 VVVF inverter 16, 16A Motor control part 17 Motor current detector 18 Resolver 19 DC voltage detector 28 Terminal voltage calculating part 35, 35A Demagnetization determination device 36 Monitor 37 Motor voltage detector

Claims (4)

Coasting operation detector for detecting the coasting operation state of the permanent magnet synchronous motor;
An induced voltage detector for detecting an induced voltage by a permanent magnet in a no-load operation state of the permanent magnet synchronous motor;
The detected value of the induced voltage by the permanent magnet in the no-load state is compared with a predetermined reference value, and it is determined that demagnetization has occurred in the permanent magnet when the detected value of the induced voltage in the no-load state falls below the reference value. A permanent magnet demagnetization monitoring device for a permanent magnet synchronous motor, comprising:   2. The demagnetization alarm output unit that outputs a demagnetization warning to a monitor provided in a cab when the permanent magnet generation determination unit determines that the permanent magnet is demagnetized. The permanent magnet demagnetization monitoring device of the permanent magnet synchronous motor described. A motor voltage detector for detecting the voltage of the current flowing through the permanent magnet synchronous motor;
The permanent magnet reduction of the permanent magnet synchronous motor according to claim 1, wherein the induced voltage detection unit detects an induced voltage of the permanent magnet from a motor voltage detection value detected by the motor voltage detection unit. Magnetic monitoring device. A data current detection unit for detecting a current flowing in the permanent magnet synchronous motor;
The permanent magnet reduction of the permanent magnet synchronous motor according to claim 1, wherein the induced voltage detection unit calculates an induced voltage of the permanent magnet from a motor current detection value detected by the motor current detection unit. Magnetic monitoring device.

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