Hall sensor-based Locking Electric Differential System for BLDC motor driven electric vehicles

This paper presents a hardware implementation of the previously introduced locking Electric Differential System (EDS) of Electric Vehicle (EV) with two independent Brushless DC (BLDC) machine-based drives. The proposed method locks the active wheels of the vehicle as if they were operating on a common shaft. The locking algorithm is realized by processing the Hall sensor signals of the considered motors and driving them with a single set of "averaged" Hall signals. The proposed Sync-Lock Controller (SLC) is implemented digitally using a programmable integrated circuit microcontroller. First, the Hall signals undergo a layer of filtering to mitigate the errors due to hall sensor misalignment. Then, the locking algorithm is implemented by averaging the filtered Hall sensor signals. The proposed technique locks the motors directly through their corresponding magnetic fields and is shown to achieve better results as compared to a conventional speed control loop. The SLC prototype is implemented in the form of a standalone dongle-circuit that can be easily placed between the original Hall-sensors and the BLDC motor driver.