DEVICE AND METHOD FOR DRIVING SENSORLESS BLDC MOTOR

A method and a device for driving a sensorless BLDC(BrushLess DC) motor are provided to reduce a torque ripple from an output current by using different unipolar PWM signals for different operation modes of the BLDC motor. A device for driving a sensorless BLDC motor includes an AC source(10), a rectifying unit(11), a capacitor(12), and an inverter(13). The capacitor flattens an output from the rectifying unit. The inverter receives a DC voltage from the capacitor and supplies a 3-phase AC voltage to the BLDC motor(14). A terminal voltage detector(15) receives the output from the inverter and detects position information of the rotor and call current information. A speed setting unit(16) determines a speed of the BLDC motor. An angle setting unit(16-1) sets an actual angle according to an operation parameter. A PWM(Pulse Width Modulation) pattern generator(17-1) receives the angle, the position information of the rotor, and the speed information, and generates a PWM pattern corresponding to the received results. An inverter driver(18) switches six switches in the inverter according to an output signal from the PWM pattern generator.