Tuning Method for PI Controllers of PMSM Dual Closed-Loop Driving System Based on Frequency-Domain Analysis
Taking the dual closed-loop driving system of permanent magnet synchronous motor(PMSM)as the object,a method of tuning PI parameters in frequency domain was proposed based on simplified mathematic model,and factors including inverter switching cycle,current and velocity filte-ring were analyzed.The expression of open-loop frequency domain parameters were derived by dual loop model.The simplified design method of PI parameters was analyzed and deduced according to the parameters of the current loop in low and middle frequency bands and inaccurately measuring of dam-ping coefficient of the speed loop.Time domain parameters were converted into the open-loop frequen-cy domain parameters by engineering experience and their values were defined reasonably according to various constraints.The feasibility of the tuning method was verified by simulation and practical experi-ments.This method defines parameters of dual loop controller,expressions of open-loop cut-off frequency and phase margin and the relationship between the open-loop frequency domain parameters and close-loop time domain parameters,which has a high enginering reference and application value.