Loss minimization control of interior permanent magnet synchronous motor (IPMSM) based on approximate calculation

In this paper, loss minimization control method of IPMSM based on approximate calculation is proposed. Firstly, according to the IPMSM mathematical model considering the equivalent iron loss, the loss minimization extreme value is solved by Lagrange equation, and the electromagnetic current variable is eliminated by the equivalent transformation method. Secondly, the relation of dq axis current is obtained by defining the virtual current. Considering the existence of the square term in the relation, a new approximate calculation method is proposed to eliminate the square term of the given current and obtain the dq axis current with the minimum loss. Finally, in order to further prove the performance of the proposed method, i d = 0 control, virtual current control method and torque approximation control method are analyzed and compared in MATLAB/SIMULINK. Simulation results show that the proposed control method is more perfect than the traditional virtual current method and has higher accuracy than the traditional approximate calculation method. Compared with the traditional three control methods, the total loss is reduced by 7.44% at least under rated working conditions.