Electric Vehicle Regenerative Braking Operation with BLDC Motor Drive

Electric vehicle (EV) is mainly driven in three different operating modes: accelerating mode, normal operating mode and regenerative braking mode. While driving in accelerating and normal operating modes, the power flows from battery to motor, whereas in regenerative braking mode, electric motor operates as generator and charges the battery through power electronics converter. Three-phase inverter circuit is used as electronics commutator to control the brushless direct-current (BLDC) motor in all required operating modes. A bidirectional DC-DC power converter is used to manage the DC link voltage at the required level as per speed command given by the driver. Bidirectional DC-DC converter is controlled in buck mode to operate the electric vehicle in accelerating and normal operating mode. In other case, the same converter is controlled in boost mode to operate electric vehicle in regenerative braking mode. In this paper, PI controllers are used to maintain required speed of the vehicle, DC link voltage and the battery current for different kind of steady state and transient operation of the vehicle as per road conditions and the driver speed command. Therefore, the performance of the power train can be optimized. In this paper, a closed loop control strategy is demonstrated for bidirectional DC-DC converter and three-phase inverter to operate electric vehicle in different operating mode and recover energy to charge the batter in regenerative braking operation. Control strategy is verified through the simulation using Simulink/MATLAB R2019b package.