A Composite Control Strategy for Suppressing the Current Harmonic at the Grid Side of V2G Charger

The V2G (Vehicle to Grid) charger is an important physical interface for EVs to provide V2G services to the grid. It not only has the charging function, but also has the function of feeding the power grid. The bi-directional charger with V2G service has a wide range of output power. The current ripple proportion at light-load becomes larger and the current response speed becomes slower, which will cause the zero-crossing distortion. And the traditional controller steady-state error will also increase, so that the grid side current harmonic proportion becomes larger lead to deteriorate in power quality. In this paper, a composite control strategy based on quasi proportional resonant (QPR) control and the weighted current (WC) control is presented. By simulation and experimental results, it is proved that this strategy has better harmonic suppression performance than traditional PI control methods, limited to 3.2%, which is conducive to the realization of electric vehicles feeding the smart grid cleanly.