1MHz variable sampling quasi multi-rate deadbeat control for single phase PWM inverter in low carrier frequency

A new approach for real time digital feedback control of PWM inverter is proposed, in which a quasi multi-rate deadbeat control combined with variable sampling method using FPGA based hardware controller. It was reported that the deadbeat control method with FPGA based hardware controller had the very good transient response for various loads, but these reports were mainly focused on a few KW class PWM inverter system, so the high carrier frequency were adopted. But in MW class PWM inverter system, the carrier frequency is limited upto 2kHz range, because of the performance of the switching devices and the trade oreg against the efficiency of the inverter is not so much expected. In the proposed method, to ensure the tracking accuracy of the output voltage to the reference voltage, 1 MHz sampled data is used while one carrier interval, and the pulse width is re-calculated every 1mu second, the dynamic performance and robustness are much improved compared with the conventional 6 kinds of digital control method. The control characteristics of the proposed variable sampling deadbeat control is verified through simulations and experiments.