Predictive Common-Mode Voltage Suppression Method Based on Current Ripple for Permanent Magnet Synchronous Motors

Compared with the pulsewidth modulation-based field-oriented control scheme, finite control set model predictive control (FCS-MPC), which has been widely concerned, has great advantages in fast dynamic response, multiobjective control, and system constraint processing. The common-mode voltage (CMV) generated by the inverter will lead to bearing damage and electromagnetic interference issues. This paper studies CMV suppression method based on FCS-MPC for permanent magnet synchronous motor fed by voltage source inverter. The use of zero voltage vector can significantly increase the output CMV of the inverter. The method of abandoning the zero vector directly can decrease CMV, but will lead to larger current distortion. Replacing the zero vector with nonadjacent vectors is a better way but will lead to higher switching frequency. When the CMV is introduced into the cost function, the tradeoff between CMV suppression and current distortion can be realized, but there is no rule to be followed for weight coefficient design. In this paper, we propose a variable FCS scheme based on current ripple. Based on this scheme, CMV can be suppressed under the premise that the current distortion is small, and the switching frequency is not significantly increased. Based on the proposed method, current distortion and CMV can be well balanced under different load conditions by setting the relative error limits. Experimental results show that the proposed method has good control performance under various operation conditions.