Contactless battery charger with bi-directional energy transfer for plug-in vehicles with vehicle-to-grid capability

Bi-directional battery charger based on an inductive coupled contactless energy transfer system is presented in this work. To minimize total losses of the system, a series resonant compensation circuit is applied assuring zero-current switching condition for insulated-gate bipolar transistor. The analytical expression of the dc voltage gain, current gain as well as efficiency is presented and discussed. The resonant frequency is adjusted by an integral control method witch guarantees very fast and stable operation. Some simulation and experimental results illustrating the operation of the developed 25-kW laboratory prototype are given.