Based on the relationship between the inverter equivalent load and the DC-side input current of the wireless charging system

a load estimating method using DC-side input current is proposed. Firstly

a model is developed to analyze the relationship between the DC-side input current and the inverter output current. Then

the mathematical relationship between the input current and the load is derived. Thus the load estimating based on the DC-side input current is accomplished. Furthermore

simulations and experiments have been conducted to verify the proposed load estimation method. Experimental results show that the estimation error is less than 10% within the load range of 10~100 Ω. Finally

the proposed load estimating method has been used to conduct system fault analysis. The results show that the load estimating method is able to achieve effective identification of system fault states.