The realization of power stabilization and reactive power minimization for wireless charging system under high coils misalignment

In order to realize output power stabilization and reactive power minimization under possible coils misalignment occasion, a wireless power transfer system with improved primary modulation strategy and switch- controlled-capacitor (SCC) structure is proposed. The main contribution is that mutual inductance and primary self-inductance value can be estimated accurately via only virtual value of primary voltages and currents. No bulky auxiliary circuit, wireless communication, complex calculation and strict waveform quality is needed during the estimation process. Then according to the estimation result, a SCC structure and attendant control strategy is adopted to maintain the reactive power minimization. Besides, an improved primary phase shift (PS) modulation is proposed to realize the output power stabilization and enhance the system transmission efficiency. Finally, an experimental platform is built to verify the feasibility of proposed method.