Abstract：According to the problem that a high-power inverter and a power improper cause impact current and speed fluctuations due to improper switching,a synchronous switching method is developed between the variable frequency and power frequency of an AC asynchronous motor based on predictive control. The inverter output voltage signal and power frequency voltage signal synchronized are sampled by using TMS320F2812 DSP chip,and the difference between two input signals is obtained by a phase operation. Then it calls the predictive control algorithm procedures to achieve phase lock control. When the inverter output voltage and power frequency voltage phase achieve consistently,DSP will control a relay so as to realize that a motor switch from a frequency conversion circuit to a power grid smoothly and without interference. The simulation results show that the design has fast and excellent tracking characteristics and strong robustness.

Keyword：predictive control;TMS320F2812;software PLL;synchronous switch;