A Novel Sensorless Control Method for BLDC Motors Based on Back-EMF

Generally, conventional Brushless DC (BLDC) motor drives typically rely on physical transducers, such as encoders or Hall-effect sensors, to acquire rotor position feedback. To enhance system robustness and reduce costs, sensorless control for trapezoidal-type BLDC motors has become a critical area of research. This paper introduces an innovative commutation signal extraction technique that derives rotor position directly from the Back Electromotive Force(Back-emf) and using a multi-function OP-AMP circuit. However traditional sensorless method that necessitate motor neutral voltage monitoring, multi-stage analog filtration, or computationally intensive digital phase-lag compensation, the proposed architecture streamlines the signal processing. By synthesizing commutation triggers from the integrated average phase voltage rather than identifying the zero-crossing points (ZCP) relative to a floating neutral, the system eliminates the requirement for a physical or virtual neutral point. This approach significantly bolsters immunity against common-mode switching noise and simplifies the hardware-software interface. The effectiveness and precision of the proposed control algorithm is verified through simulation results.