Robust nonlinear control of battery electric vehicle charger in grid to vehicle applications

The charging unit of battery electric vehicle (BEV) is one of the primary subsystems which allows its interconnection with the charging facility. Due to the nonlinear behavior of the power conditioning circuitry and its sensitivity to external disturbances, robust nonlinear controller is required to achieve various control objectives like output voltage regulation and power factor correction in grid to vehicle (G2V) mode. For this purpose, an integral backstepping sliding mode controller (IBS-SMC) and backstepping sliding mode controller (BS-SMC) is designed in order to achieve these objectives. But their responses exhibit the phenomenon of chattering which is highly undesirable and can cause heat and power losses in the system. In order to mitigate the effect of chattering, supertwisting sliding mode controller (ST-SMC) has been designed which not only reduces the effect of chattering but also exhibits a better dynamic performance in controlling the BEV charger in G2V mode. The global asymptotic stability of the system for the proposed controllers has been proved using Lyapunov stability criterion. The proposed controllers have been simulated on Matlab/Simulink in which ST-SMC has been compared with IBS-SMC and other nonlinear controllers in the literature. The robustness of the designed controllers have also been checked by adding external disturbances in the plant. The results show negligible chattering and better dynamic response of ST-SMC as compared to other controllers. To further validate the designed controller experimentally in G2V mode, hardware in the loop (HIL) simulations have been done using Delfino F28379D dual core microcontroller which further prove the effectiveness of the proposed controller for BEV charger.