The study of PWM methods in permanent magnet brushless DC motor speed control system

The permanent magnet brushless DC motor speed control system (PMBDCSCS) is simple control, high power density and high performance, and used in many domains. The voltage inverter used widely in the PMBDCSCS operates commonly in the six PWM methods: H_PWM_L_PWM, ON_PWM, H_PWM_L_ON, H_ON_L_PWM, PWM_ON and PWM_ON_PWM. In this paper, the six PWM methods are introduced in theory and are compared in detail at the system level, the analysis is proved true by the simulation result.