A Parameter Identification Approach With Primary-Side Measurement for DC–DC Wireless-Power-Transfer Converters With Different Resonant Tank Topologies

Mutual inductance and load condition of a wireless-power-transfer system are essential parameters to regulate the output voltage and power or track maximum efficiency. This article proposes a parameter identification approach for the dc-dc WPT resonant converter only requiring the primary-side measurement to identify the mutual inductance, output voltage, output power, and efficiency under unknown varying misalignment and load conditions. The approach is widely applicable to series-series, series-parallel, parallel-series, parallel-parallel, and LCC-C topologies and can estimate the value variation of the resonant capacitors, which are the unique advantages compared with other existing methods. Moreover, there is no restriction on the operation frequency selection. The direct-quadrature transformation technique is applied to acquire the fundamental and third-order harmonics information of primary-side voltage and current accurately. Detailed analysis, hardware design, and laboratory prototype are presented with experimental results to validate the correctness and accuracy of the proposed approach.