Research On Wireless Charging Of Electric Vehicles With Complementary Micro - Grid

Electric Vehicles(EVs) has attracted more and more national attention, EVs electrification is the future development trend. However, EVs charging problem is one of the key issues which restricts the development of EVs. Distributed generation(DG) and EVs charging are integrated into microgrid, researching control strategy for microgrid for EVs wireless charging will effectively promote the popularity of EVs, at the same time effectively increase renewable consumptive capacity.Utility of the advantages of microgrids and wireless power transmission, hierarchical control of photovoltaic (PV) microgrid is explored for electric vehicles (EVs) reliable charging, which provides a new way for EVs charging. Stand-alone PV microgrid is composed of PV panels and batteries. The possible operation states are investigated by analyzing the relationships between the maximum power output of the PV and load power. A hierarchical control strategy of PV microgrid is established, which includes the central controller and the local controllers. The central controller is responsible for the choices and switches of operation states and the management of the local controllers; the local controllers include wind power generation MPPT((maximum power point tracking)controllers, battery charging/discharging controller of PV microgrid, voltage controller of DC bus for high-frequency inverter and onboard battery charging controller. By optimizing and matching parameters of transmitting coils, receiving coils and compensation capacitors, the wireless power transmission system is designed to be resonant. Its aim is to achieve the best transmission system efficiency. For the connection of different capacity onboard battery, the voltage controller of DC bus for high-frequency inverter is used and the reference voltage can be adaptively adjusted by detecting the charging power of the onboard battery. Simulative system and experimental system of PV microgrid with EVs wireless charging are established. The simulative and experimental results show that the hierarchical control strategy makes wind/solar hybrid microgrid provide stable power for EVs wireless charging when the illumination and wind changes or on-board batteries charging power changes. This method can solve EVs charging impacts on grid, and can increase the flexibility of EVs charging.