LCL Compensated Series Transmitter Array Based Inductive Wireless Charger for Multiple EV Charging Application

This paper presents a LCL compensated series connected transmitter coils array based wireless inductive charging system for multiple receivers which can charge several EVs simultaneously and independently. LCL compensation offers a constant transmitting coil current which neither depends on number of transmitting coil connected at its output nor on coupling and load resistance of a connected EV. A tuning capacitor is used in series with each transmitting coil to maintain resonance in the system. This makes system flexible to isolate the particular transmitting coil set which is not coupled with any receiving coil while other transmitting coils are supplying power to EVs. Relay switches are used to isolate the coil. This system adopts only a single inverter and common primary LCL compensation to excite all the series connected transmitting coil set which reduces number of passive elements in primary. Cross coupling of a coil with adjacent transmitter or their receiver coil is neglected. Simulation study is performed with an example of three transmitter system. Results shows that all channels are independent from each other. Output voltage and power from a channel is independent of coupling and load condition of other channels. The system operates at zero phase angle at input and transmitting coil current is constant irrespective of number of EVs connected in the system. To validate the system a scaled down experimental prototype is developed form 150V input to 75V output.