Electrical loss minimization strategy for interior permanent magnet synchronous motor drives

An electrical loss minimization strategy for interior permanent magnet synchronous motor drives is proposed in this paper. Until now a Look-up Table based maximum torque per armature current control strategy was proposed by authors. That is a control to minimize copper losses. Meanwhile, the efficiency deteriorates as a result that the iron losses increase sharply in high speed area. In this paper, a model considering iron losses is discussed and the relationship between the electrical losses and d-q axes current, motor torque, motor speed is clarified at first. Next, measurement experiments are made to prove that there is an optimal armature current phase which minimize the electrical losses for given motor speed and load torque. The current vector trajectories at which the copper losses will be minimal or the electrical losses will be minimal are given. Then, a Look-up Table based electrical loss minimization strategy is proposed. The driving efficiency with i_d = 0 control, maximum torque per armature current control and electrical loss minimization control are compared with experiment results. The effectiveness of the proposed control is verified by experiments.