Predictive Flux Weakening Control of PMSMs Supplied From Reduced-Switch-Count VSI

The application of a reduced-switch-count voltage source inverter in multimotor systems (MMSs) presents a viable solution to achieve higher power output with reduced costs. This article presents an optimized predictive flux weakening control (PFWC) strategy designed for multimotor drives. First, an enhanced dual-vector model predictive control scheme is adopted for driving an MMS considering the case of inverter leg sharing. According to the deadbeat principle and geometric method, the optimal voltage vectors (VVs) are selected without the need to traverse the complete candidate vector set. The duty cycles of output VVs are calculated and modified to realize higher voltage utilization and power output with the switching-state coordination. Subsequently, in relation to flux weakening (FW) control, the requisite
d
-axis current is directly calculated using an enhanced global feedforward algorithm. The voltage margin coefficient is obtained by a voltage feedback scheme with proportional-integral controller. Simultaneously, the entire dc bus voltage is adaptively allotted to multiple motors. Eventually, the proposed PFWC scheme is successfully implemented on a three-motor system, and the test results demonstrate the effectiveness and superiority of the scheme.