Speed Control Modeling for In-Wheel Permanent Magnet Brushless DC Motors for Electric Vehicles

In this decade, modern Battery Electric Vehicles (BEVs) had witnessed the intervention of in-wheel BLDC motors which led to improved overall efficiency due to the absence of both; the mechanical power train and the brushes. In the present work, a detailed parameterized model of a PM-BLDC motor is considered to estimate its torque-speed characteristics accurately. Three differential equations are simultaneously solved to estimate the motor characteristics. Additionally, an electric drive system is fully modeled including: Li-ion battery, six-step voltage inverters and Hall sensors in the presence of disturbance load torque. For the complete motor parameters to be fed to the model, experimental system identification is implemented. The steady-state response behavior of the motor is validated. In order to control the motor's rotational speed with enhanced transient response, a PID speed controller is implemented. The controlled BLDC motor model results include the speed, back EMF, motor torque and armature phase currents. The results show that, the proposed in-wheel PM-BLDC motor model could be reliably employed as a tool for BEVs modeling.