Parameter Estimation of Wireless Power Transfer Systems Based on the DC Input Voltage and Current

The paper presents a parameter estimation method of wireless power transfer (WPT) systems based on the dc parameters on the primary side. The method can simultaneously realize the estimation of the mutual inductance and the output current, only using the dc input voltage and current of the inverter. Firstly, a model of a WPT system with SS compensation network is built. According to the model, the dc input current and output current are expressed by the mutual inductance, the battery voltage and the dc input voltage. Considering that the soft-start process lasts for a short time, the battery voltage is treated as a unchanged value in this process, and two groups of the dc input voltage and current are used to estimate the mutual inductance. Then, the output current is obtained based on the estimation result of the mutual inductance. Finally, A prototype of a WPT system is built and experiment are conducted to validate the effectiveness of the proposed estimation method.