scholarly journals Failure Diagnosis of Demagnetization in Interior Permanent Magnet Synchronous Motors Using Vibration Characteristics

2019 ◽  
Vol 9 (15) ◽  
pp. 3111 ◽  
Author(s):  
Takeo Ishikawa ◽  
Naoto Igarashi
Keyword(s):  
Vector Control ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Vibration Characteristics ◽  
Failure Diagnosis ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Light Load ◽  
Interior Permanent Magnet ◽  
High Degree

The detection of a precursor to the demagnetization of permanent magnets is very important because a high degree of reliability is necessary in permanent magnet synchronous motors (PMSMs). This paper investigated the diagnosis of very slight PM demagnetization. A part of the permanent magnet was altered to non-magnetic material so as to mimic the effect of demagnetization. The vibration characteristics were clarified for low demagnetization in PMSMs driven under vector control by experiments and 3D finite element (FE) analysis. We found that the amplitude of some components of the vibration was approximately proportional to the demagnetization level of the PM and the load torque. Therefore, the measurement of vibration and torque is very useful for the estimation of the magnetization level of PMSMs under vector control except for under very light load.

scholarly journals Failure Diagnosis for Demagnetization in Interior Permanent Magnet Synchronous Motors

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Takeo Ishikawa ◽  
Naoto Igarashi ◽  
Nobuyuki Kurita
Keyword(s):  
Vector Control ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Low Frequency ◽  
Axial Direction ◽  
Permanent Magnet Synchronous Motors ◽  
Element Analysis ◽  
Synchronous Motors ◽  
Interior Permanent Magnet ◽  
Axis Position

Since a high degree of reliability is necessary for permanent magnet synchronous motors, the detection of a precursor for the demagnetization of permanent magnets is very important. This paper investigates the diagnosis of very slight PM demagnetization. The permanent magnet volume is altered so as to mimic the effect of demagnetization. This paper investigates the influence of demagnetization by using several methods: the 3D finite element analysis (FEA) of the motor, the measurement of high-frequency impedance, and the measurement and FEA of the stator voltage and current under vector control. We have obtained the following results. The back-EMF is proportional to permanent magnet volume, and there is no difference in the demagnetization in the radial direction and in the axial direction. Even harmonics and subharmonics of flux density at the teeth tip could be useful for diagnosis if a search coil is installed there. The relatively low frequency resistance at the d-axis position is useful for diagnosis. Under vector control, the stator voltage is useful except in an intermediate torque range, and the intermediate torque is expressed by a simple equation.

scholarly journals Properties, Characteristics and Parameters of Permanent Magnet Synchronous Motors under Vector and Scalar Frequency Control

2019 ◽  
Vol 62 (3) ◽  
pp. 205-218 ◽  
Author(s):  
B. I. Firago ◽  
S. V. Aleksandrovsky
Keyword(s):  
Vector Control ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Frequency Control ◽  
Asynchronous Motor ◽  
Energy Performance ◽  
Permanent Magnet Synchronous Motors ◽  
Technical Literature ◽  
Synchronous Motors ◽  
Electric Drives

In order to improve energy performance and simplify the system of frequency control of the speed of electric drives, the area of application of synchronous frequency-controlled electric drives with both dependent and independent frequency setting of the voltage supplying the engine is being expanded. This is due to the fact that, as compared with asynchronous variable frequency drives, synchronous ones undergo lower power losses and they have rigid mechanical characteristics without speed feedback. Also, the simplest law of frequency control, viz. a proportional one, which, however, provides the maximum electromagnetic torque of the engine unchanged at R1 = 0 at all frequencies due to the constant magnetic flux, is applicable to a synchronous frequency controlled motor. Characteristics and properties of permanent magnet synchronous motors (PMSM) with the dependent frequency setting of supplied voltage (under vector control of PMSM) have been discussed and reviewed in technical literature quite sufficiently. It cannot be said about the PMSM with independent frequency setting reference which work under scalar frequency control. In the present article a comparison of properties and characteristics of vector and scalar frequency controlled PMSM is presented. For a scalar frequency controlled PMSM a function of the relative voltage g on the relative frequency a (g = f(a)) taking into account the PMSM parameters has been defined. The derived function g = f(a) differs from a proportional law of frequency control g = a. It is found that the influence of the parameters on the law of frequency control is small, and it can be applied without adjustment in most cases, in contrast to the frequency control of the asynchronous motor. For scalar frequency control, a method for determining the parameters of synchronous motors has been proposed in accordance with the parameters of synchronous motors with permanent magnets, which are given for operation under vector control. According to the presented methodology the OMRON SGMH-50D engine parameters have been determined for scalar frequency control and the function of g = f(a) have been computed.

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