Tuning method for digital PI controllers of PMSM closed-loop driving system

In order to obtain a simple and accurate design method of digital PI controller parameter for permanent magnet synchronous motor, the method of tuning PI parameters in continuous domain is improved.A discrete design method of tuning parameter in the w^' domain was employed. The phase lag caused by the sampling time and the zero-order holder (ZOH) were directly reflected in the design process.The mathematical model of every link of the system was determined and the discrete model block diagram of the closed loop system was got in the first place. And then, the time domain performance index was transformed into the open-loop frequency domain feature value by engineering experience, which was followed by the analysis in the w^' domain. In this paper, the tuning process contained current loop analysis prior to speed loop. The simulation and experiment show that the results obtained by the proposed method meet the performance requirements, with an overshoot of less than 5% and settling time of about 1.92 s, which proves that this method can provide the guidance for parameter tuning of digital PI controller.