Adaptive Sliding Mode Controlled on-Board Dual Stage EV Charger with Enhanced Power Quality

This paper presents an Onboard Dual-Stage EV Charger (ODEC) with a boost Interleaved Power Factor Correction (IPFC) unit integrated with Capacitor-Inductor (CLLLC) resonant Dual-Active Bridge (DAB) converter. Onboard Chargers (OBC) are expected to enhance power quality on the mains supply side while maintaining compactness, high power density, and robustness against zero-crossing impulse currents. Proportional Integral (PI) control exhibits decreased robustness with parameter changes, non-linearities, limited eigenvector placement, and nonminimal phase elements. Double-Integral Sliding Mode Control (DI-SMC) circumvents these shortcomings, and thus a PI-based hybrid dual-loop DI-SMC control technique is proposed, in this paper. The hybrid control includes a PI-based dual-loop DI-SMC control loop, where the outer loop regulates a DC link voltage and inner loops regulate the boost inductor currents. CLLLC DAB includes a phase control loop that regulates the output charging port voltage. It is observed that the PI-based dual-loop DI-SMC implementation of IPFC is a PI dual-loop structure with additional active feed-forward compensation improving the input current quality. Further, a Second-Order Generalized Integrator with Phase Locked Loop (SOGI-PLL) is used to track the grid angle for unit vector template generation for IPFC reference currents. Validation of the proposed technique has been done in simulation and hardware, and the results are discussed.