Wide Bandgap Semiconductor Based Electric Vehicle Charging Systems: Modeling, Magnetics, and Control

Adhering to an ever-increasing demand for innovation in the field of onboard electric vehicle (EV) charging, several technical aspects pertaining to the design and performance enhancement of integrated multi-port charger topologies are discussed in this study. This study also elucidates various research challenges pertaining to each module of the topology and elucidates technically validated solutions for each.Firstly, targeting the input side totempole power factor corrector (TPFC) circuit, a novel digital filter based Active Mitigation Scheme (AMS) is proposed to curb the third harmonic component, along with a novel discretized sampling-based robust control scheme. Experimental verification of these techniques yields an enhanced Total Harmonic Distortion (THD) of 1.68%, enhanced efficiency of 98.1% and resultant power factor of 0.998 (lag). Further, focusing on the bidirectional CLLC based DC/DC converter topology, a general harmonic approximation (GHA) based secondary side turnoff current minimization technique is discussed. Numerous fabrication and design-based constraints and correlations for parametric modelling of high frequency planar transformer (HFPT) are explained with analytical and 3D Finite Element Analysis (FEA) findings. Further, characterization of the plant transfer function of all-inclusive CLLC model is described along with hybrid Sliding Mode Control (SMC) based control scheme. The steady state experimental results at 1kW rated load show a peak efficiency of 98.49%, while the quantification of dynamic response portray a settling time reduction of 46.4% and an over/undershoot reduction of 33%. Further, comprehensive modeling of triple active bridge (TAB) DC/DC converter topology is presented with special focus on the control scheme and decoupling capabilities to independently regulate the output bridges. With an objective to reduce the overall losses and to add a dimension of controllability, a three-loop control scheme is proposed with power flow optimization. Inculcating the benefits of multiport and resonant topologies, a comprehensive multi-variable loss optimization study of a Triple Active C^3 L^3 (TAC^3L^3) converter is discussed. The performance of eight different hybrid modulation schemes is compared with respect to the developed global loss minimization objective function. Experimental validations for various loading conditions are presented for a wide-gain bidirectional operation (400V/500-600V/24-28V), portraying a peak converter efficiency of 97.42%.