Accurate Estimation of Rotor Position and Speed for BLDC Motor Drives During Faulty Hall Sensors

A brushless direct current (BLDC) motor, a permanent magnet synchronous machine variant controlled by three Hall-effect sensors, is widely employed in various industrial applications for better controllability and performance. The drive operation mainly depends on rotor position and speed for a decent switching commutation. Almost all the sensored BLDC motor dives in the literature rely on the ideal placement of the three Hall sensors at 120 electrical degrees apart. However, the sensors may be inaccurately placed and generate unbalanced signals or get faulty and lose the signals leading to degrade the drive performance due to wrong rotor position and speed information. This paper developed a comprehensive sensored fault-tolerant control (FTC) to precisely estimate the continuous rotor position and accurate speed for Hall-sensor-controlled BLDC motor drives during unbalanced and faulty Hall signal errors to properly function the drive’s inverter and mitigate the current/torque ripples. The Hall signals’ errors are quickly diagnosed and separately classified for faster signal identification and reconstruction. The proposed FTC approach provides straightforward implementation without modifying the drive system and circuit. The investigated scheme is verified through MATLAB/Simulink tools under steady-state and transient operation conditions.