A Dual Two-Vector-Based Model Predictive Flux Control With Field-Weakening Operation for OW-PMSM Drives

Abstract

This article proposes a dual two-vector-based model predictive flux control (DTV-MPFC) strategy for open winding permanent magnet synchronous motor drives with two isolated voltage source inverters (VSIs). In the MPFC strategy, the reference stator flux vector can be compensated to realize field-weakening (FW) operation by controlling the value of the cost function. However, the accuracy of the cost function based FW strategy is limited when the tracking error of the stator flux vector exists. In this article, a DTV-MPFC strategy is proposed to synthesize the reference flux increment vector precisely and the FW operation boundary is kept within the linear modulation region to enhance the FW operation performance. Each inverter applies two vectors during the control period and the switching frequency of the VSIs is minimized with the proposed strategy. When the dc-link voltages of the VSIs are unequal, the number of candidate flux increment vectors and the distribution of the space vector plane are different. A generalized vector selection and duration calculation scheme is proposed to realize the DTV-MPFC strategy in this case. Experimental studies are carried out to verify the validity and effectiveness of the proposed strategy.