Research on Current Loop Composite Control Strategy for Stator Core Loss Test

In order to test the loss of the stator core before the motor is manufactured, it is required that the total distortion (THD) of the current generated by the inverter output voltage applied to the tested object does not exceed the limit value. Through the analysis of the tested object, the relationship between the equivalent inductance value and the current is nonlinear, so that the harmonic content of the system is high, and the traditional control algorithm is difficult to meet the demand of the current waveform. In this paper, a composite control algorithm of PI controller and repetitive controller in parallel combined with quasi-resonant controller is proposed, based on the characteristics of the controlled object, together with a voltage type single-phase full-bridge inverter to realize the closed-loop control of the current. The structure and parameter design method of the control algorithm are given. Finally, the effectiveness and feasibility of the composite control algorithm are proved by experiments.