Optimal-efficiency control for constant-power operation of phase-decoupling permanent-magnet brushless motor drives

In this paper, a control approach to optimize the system efficiency of phase-decoupling (PD) permanent magnet (PM) brushless motor drives during constant-power operation is presented. The approach is to adaptively adjust the advanced conduction angle to minimize the total system losses for a given operation point in the constant power region. The corresponding minimum total losses are determined by minimizing the input current for a fixed voltage source. Both computer simulation and experimental results are given for illustration.