Current optimization-based control of dual three-phase PMSM for low-frequency temperature swing reduction

Abstract

In this paper, a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor (DTP-PMSM) drive to reduce the low-frequency temperature swing. The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper. First, a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed. Then, the optimization is transformed to a single-level optimization by introducing the auxiliary variable for easy solving. Considering that single-objective optimization trades a great total copper loss for a small reduction of maximum phase copper loss, the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed, which has the same performance of temperature swing reduction but with lower total loss. In this way, the proposed control scheme can reduce maximum junction temperature by 11%. Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.