Common Mode Current Suppression in Full-Bridge Converter Based on Simulated Annealing Algorithm

In PWM converter, the serious electromagnetic interference (EMI) is occurred due to high speed operation of switch devices. In this paper, production mechanism of common mode (CM) current in single phase full-bridge converter is analyzed, and severe affection to CM current owing to different transmission delays of two drive pulses is illustrated. It is proposed a digital CM current suppression method based on optimal drive pulses. A novel evaluation measure for CM noise level based on the energy of CM noise current is proposed. The relationship between CM noise level and the delay time of drive signals is studied. Simulated annealing searching algorithm is used to search for the global optimum of CM current energy. Simulated results show that CM current suppression based on simulated annealing algorithm (SAA) can regulate the delay time of drive signals without getting trapped at local minimums. It suppresses CM current level effectively and improves the EMC performance of PWM converter