Qin Liang

Real-time algorithm research and realization of Optimal Unsymmetrical PWM method

As the work frequency is very low, the Optimal Unsymmetrical PWM Method is suitable to be applied in high-power situation requiring control of fundamental and harmonics simultaneously, which will reduce the switch loss and the EMI greatly. Because of the low work frequency, the optimal unsymmetrical PWM method requires optimizing each independent switch angle in order to achieve good control effect, and it needs to solve the nonlinear equations on-line inevitably to obtain the switch angle. A new algorithm by combining the predominance of the Newton and homotopy algorithms is proposed, which can effectively realize switch angle on-line computation with relative high convergence rate. At last, this paper validated the real-time performance and the effectiveness of the switch angle algorithms on the experimental platform with the control core of TMS320F2812.