Enhanced speed control of BLDC motor using a four-switch voltage source inverter and sensorless position estimation

A sensorless control strategy for Brushless DC (BLDC) motors in electric vehicles (EVs) using a three-phase four-switch voltage source inverter (FSVSI) is presented. The proposed topology reduces circuit complexity and switching losses compared to conventional six-switch inverters. Rotor position is estimated via an observer-based back-EMF detection method, ensuring accuracy at low speeds. Proportional–Integral–Derivative (PID) gains are tuned using Particle Swarm Optimization (PSO), Equilibrium Optimization (EO), Adaptive Equilibrium Optimization (AEO), and Ziegler–Nichols (ZN) methods to minimize overshoot, undershoot, and torque ripple. The AEO algorithm, introduced here as a novel approach, is benchmarked against other tuning methods using Integral Absolute Error (IAE), Integral Squared Error (ISE), and Integral Time Absolute Error (ITAE) indices. Real-time validation is performed on a dSPACE 1104 platform for eight configurations: PSO-6S, PSO-4S, EO-6S, EO-4S, AEO-6S, AEO-4S, ZN-6S, and ZN-4S. Results demonstrate that AEO-4S achieves the lowest steady-state error and reduced torque ripple, while the FSVSI offers inherent advantages of reduced component count and significantly lower switching losses.