Current Control Strategy for the Sensorless Speed Control of Permanent Magnet Brushless Direct Current Motor

─ Brushless dc (BLDC) motor drives are continually gaining popularity in motion control applications. Therefore, it is necessary to have low cost, but effective speed/torque characteristics. A Brushless DC (BLDC) drives are known for higher efficiency and lower maintenance. As the name implies, BLDC motors do not use brushes for commutation instead, they are electronically commutated. For effective utilization of the developed BLDC motor, an Inverter controlled current controlled strategy. In which a combination of both PWM and hysteresis current control schemes are designed and implemented to produce the desired dynamic and static speed-torque characteristics by proposes a new optimized sensorless drive for speed control of BLDC motor, which is based on back-EMF zero crossing detection (ZCD) of only one phase voltage of BLDC motor. This commutation technique of BLDC motor significantly reduces sensing circuits and cost of motor drive.. The speed can be controlled in a closed loop by measuring the actual speed of the motor. The error in the set speed and actual speed is calculated by using proportional-integral controller.