Multiple Parameters Estimation Based on Transmitter Side Information in Wireless Power Transfer System

Due to the electrical isolation nature of wireless power transfer (WPT) system, a method that can obtain the receiver side parameter only based on transmitter side information is desirable. However, typical estimation scheme assume that the coil inductance and compensation capacitance are constant, which will cause large estimation errors in high frequency system. Therefore, a multiple parameters estimation algorithm that can simultaneously identify load resistance, mutual inductance and receiver coil inductance is proposed in this paper, where only the input current and voltage are needed to be measured. Moreover, in order to cope with capacitor aging effect and manufacturing tolerance, compensation capacitance estimation algorithm is also presented. Mathematical model and algorithm procedure are depicted thoroughly and the gradient descent approach is adopted to obtain the optimal estimated parameter. The uniqueness of solution and the validity of this approach are strictly proved as well. Finally, a WPT experimental prototype with Class-D inverter is implemented and the experimental results are provided to verify the availability and accuracy of the proposed algorithm.