DEPLOYMENT OF AN ADAPTABLE SENSORLESS COMMUTATION TECHNIQUE ON BLDC MOTOR DRIVES EXPLOITING ZSV

In sequence, a pulse train is generated by the detected ZCS of the emerged signal and properly shifted to determine the correct commutation instants. The proposed technique ensures a wide operational speed range for the drive system. A theoretical analysis of the drive system is presented, considering a BLDC motor with nonideal back-EMF. Experimental results presented in this paper validate the effectiveness and robustness of the proposed position sensor less commutation technique under various operational conditions.

BRUSHLESS DC MOTOR CONTROL:

Switch Configuration and PWM:

Brushless DC motors use electric switches to realize current commutation, and thus continuously rotate the motor. These electric switches are usually connected in an H-bridge structure for a single-phase BLDC motor, and a three-phase bridge structure for a three-phase BLDC motor . Usually the high-side switches are controlled using pulse-width modulation (PWM), which converts a DC voltage into a modulated voltage, which easily and efficiently limits the startup current, control speed and torque. Generally, raising the switching frequency increases PWM losses, though lowering the switching frequency limits the system’s bandwidth and can raise the ripple current pulses to the points where they become destructive or shut down the BLDC motor driver.

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