A study on low-cost sensorless drive of brushless DC motor for compressor using random PWM

Recently, it is increased to apply sensorless drive for BLDC (brushless DC) motor to household electrical appliances, especially in the refrigerators and air conditioners, to reduce the cost and the acoustic noise by the operation and to make their functions more comfortable for human beings. In this paper, low-cost sensorless drive for BLDC motor is implemented by random PWM (pulse width modulation). The experimental results show that the electromagnetic noise was reduced and the sound quality was improved by BLDC motor sensorless random PWM Control.