Modeling and analysis of wireless power transfer system with constant-voltage source and constant-current load

Wireless charging for electric vehicles is gaining more and more popularity recently. This paper analyzes the wireless power transfer (WPT) system with a constant-voltage source and a constant-current load, which is featured in series compensation in the transmitter and parallel compensation in the receiver. The source voltage and the load current are square waves with fixed amplitudes. The closed-form expressions of the output power and the transfer efficiency are deduced by means of the phasor diagram and with the introduction of the transmitter admittance. The conditions to achieve the maximum output power and the maximum transfer efficiency and their maximum values are derived. An experimental prototype is implemented to verify the analysis. The theoretical analysis is helpful for the design of a WPT system with a constant-voltage source and a constant-current load.