Intelligent Control Methods for Sensor Less Control of BLDC Motor Drive used in High Speed Applications

Brushless dc (BLDC) motors and their drives are penetrating the market of home appliances, HVAC industry, and automotive applications in recent years because of their high efficiency, silent operation, compact form, reliability, and low maintenance. Traditionally, BLDC motors are commutated in six-step pattern with commutation controlled by position sensors. To reduce cost and complexity of the drive system, sensorless drive is preferred. In this paper, a fuzzy logic controller(FLC) for sensorless brushless dc (BLDC) motor. The proposedFLC is based on the terminal voltage measurement as thesensorless method for BLDC motor control. There are twomodules designed in the speed control of BLDC motor, i.e.command and regulating modules. Command module is to findand issue commutation period and PWM duty cycle to the BLDCmotor for desired speed. The regulating module is designed byapplying a FLC with sensorless technology and is used toregulate the speed of BLDC motor under various disturbances,such as loading effect. A new scheme is proposed for sensor-less control of PMBLDC motor for aligning its rotor at a known position.