Grid Synchronization of Bidirectional Electric Vehicle Chargers Using Second Order Generalized Integrator based Phase Lock Loop

With increasing interest in renewable energy sources and technologies, widespread penetration of Electric Vehicle (EV) into the power grid and use of distributed energy resources (DERs) is anticipated in the near future. Vehicle-to-Grid (V2G) is a convenient technology that allows EVs to act as distributed sources, that can store or release energy at suitable times, and in the result of a bidirectional power flow between the AC mains and DC EV batteries. This bidirectional power flow is achieved using bidirectional power electronics converters that places between the Grid and the EV battery. The Phase Locked Loop (PLL) is one of the most important parts in controlling the EV charger. It provides synchronization to the grid to efficiently control the grid current and switching sequence. Different PLL technologies are presented in the literature. Meanwhile, second-order generalized integration (SOGI) methods have a stable state and satisfactory dynamic performance. In this paper, application of the SOGI method in bidirectional EV Charger is investigated. The paper exploits the adjustments of the SOGI structure and the effect of parameters on the system dynamics. The performance of grid-connected power converters extremely depends on the synchronization strategy. Single-phase PLL with a SOGI as quadrature signal generation subsystem provide proper grid synchronization in the case of harmonically distorted grid voltage. The simulation results based on MATLAB/Simulink are provided to verify the stability of the system. Also, experimental results are carried out to validate the numerical analysis and simulation results.