Line adaptive PAM & PWM drive for BLDCM

Conventional BLDCM drives, which are supplied from the PWM inverter with DC bus connected to a diode rectifier, are of several essential drawbacks such as low power factor and high THD in the input current. This paper describes a line adaptive Boost PFC+PAM & PWM drive. With this line adaptive method, the DC bus voltage is varied as low as possible with the line voltage, the speed range of PAM mode is extended in low line and the PWM duty is enlarged in high line. The detailed scheme and design are also presented. Experimental results show that the proposed drive can achieve high PF, low THD and high efficiency for universal line input.