Stabilization control of sensorless sinusoidal wave drive for control of power factor of PM motor

Permanent-magnet synchronous motors (PMSMs) with a sinusoidal back EMF are widely used in domestic appliances for reduction of acoustic noises and energy consumption. PMSMs are generally controlled with a sinusoidal waveform current. Typically, PMSMs are controlled by vector controlled sinusoidal drives, which require powerful computational resources. Hence, simpler sinusoidal wave drives such as V/f drives, which control the phase difference between the motor voltage and the motor current (power factor of PM Motor) have been proposed for controlling PMSMs. However, those simple drive systems such as V/f drives fall into an unstable state under specific conditions. This paper presents a new method for stabilization control of sensorless sinusoidal wave drive based on power factor control of PMSMs. Using this method, extensive calculation and high performance CPUs are not required.