A Current Measurement Offset Error Elimination Method Based on Signal Injection for Interior Permanent Magnet Synchronous Motor Drives

Abstract

Accurate information of the measured phase current is of high importance for interior permanent magnet synchronous motor (IPMSM) drives. However, under the long-term effects of electrical and thermal stress, the current sensors may suffer from the current measurement offset errors (CMOEs), which causes obvious speed fluctuations and torque ripples. To address this, a current measurement offset error elimination (CMOEE) method based on the signal injection is proposed in this paper, which enables to maintain the performance of the IPMSM drives. In the proposed CMOEE method, the effects of the CMOEs on the performance of the IPMSM drives are analyzed. On the basis of this, the details of the proposed CMOEE method are provided. Then, considering that the response of the injected signal is extracted by the band-stop filter, obvious amplitude attenuation and phase deviation are introduced into the proposed CMOEE method. With this, the performance of the proposed CMOEE method may be degraded. Accordingly, a simple yet effective compensation method is adopted. Consequently, the amplitude attenuation and phase deviation are effectively compensated, ensuring the performance of the proposed CMOEE method. Finally, experimental tests are carried out to verify the effectiveness of the proposed CMOEE method under different cases.