Simplified Control Strategy to Precisely Control the Reactive Power Through Bi-directional Switching in Single Phase Bidirectional AC/DC Converter for V2G Techniques

Vehicle to grid (V2G) has great potential in smart grid and electrical market as it can decrease the fluctuation of power grid. The bidirectional converter plays a very important role in V2G techniques since it makes the bidirectional power flow possible. In order to precisely control the active and reactive power to grid, the PQ theory is commonly used. But it contains large computational burden. The simplified control strategy that corrects current reference phase (ICRP) is used. But when the bidirectional converter works at light load or when the converter switches between AC/DC mode and DC/AC mode, it's found that there is significant reactive power flow which contributes to the steady state error when with new strategy ICRP. In order to precisely control the reactive power, this paper presents a strategy by modifying inner current reference amplitude (ICRA). This strategy can be easily applied without adding any hardware. Compared with the traditional way which usually corrects inner current reference phase (ICRP) to reduce the reactive power, the theoretical analyses have been performed. Simulation has also been finished with the new strategy. Finally, experiment verifies the conclusion.