Dynamic Current Tracking for an On-board Bi-directional EV Charger with G2V and V2G Modes of Operation

A robust non-linear adaptive sliding mode current control technique for vehicle-to-grid (V2G) and grid-to-vehicle (G2V) charging operation is presented in this paper for an onboard EV charger. The proposed controller provides a stable operation during a wide variation in power demand from either side of the distribution grid or plug-in EV (PEV). The current controller plays a crucial role during bi-direction fast charging operation and the requirement of an adaptive dynamic controller is inevitable in achieving variable reference current perturbation. The proposed controller operation is guaranteed with faster convergence during variable reference tracking within a wide range of operation. The parameter variation including the unmodelled input current disturbance during the fast charging operation of the PEV is well addressed by the implementation of proposed dynamic gain adjustment technique. The gain adaptation by the controller is designed to provide a better transient performance by providing an additional sliding surface error minimization technique. The unity power factor operation is also ensured to improve the grid power quality during PEV charging operation from a single-phase distribution grid. Simulation studies provide a detailed inside of the controller performance, while a hardware prototype is developed to validate the effectiveness of control implementation through a 3.3 kW level-I on-board charger (OBC) from a 230V single-phase distribution grid.