Comparative Analysis of PWM and Sliding Mode Control for Speed Regulation in BLDC Motors

Brushless Direct Current (BLDC) motors are widely employed in industrial and automotive applications due to their high efficiency, compact size and superior dynamic performance over conventional DC and PMDC motors. Precise speed regulation of BLDC motors is essential for ensuring optimal performance under varying load and operating conditions. This paper presents a comparative analysis of Pulse Width Modulation (PWM) control and Sliding Mode Control (SMC) techniques for speed control of BLDC motors. A detailed mathematical model of the BLDC motor is developed, and both control strategies are implemented and tested under identical simulation conditions. The performance analysis is conducted for evaluation of rise time, steady state error, overshot in speed response during transient and steady state. The speed response analysis is also conducted for load change and change in reference speed during acceleration and deceleration of motor. The MATLAB simulation results are presented which indicates superior performance of SMC technique over PWM control with PI controller. The PWM-based control approach has ease of implementation whereas SMC shows ability to handle system uncertainties, parameter variations and external disturbances.