Control method of magnetic resonant WPT maintaining stable transmission power with wide misalignment tolerance

Many applications of wireless power transmission (WPT) require high misalignment tolerance. However, the transmission power of WPT is highly susceptible to the misalignment. To solve this problem, the magnetic resonant WPT control method with high misalignment tolerance is proposed here. First, based on the general mutual model, the complex ratio transformer model is established. This model gives an intuitive physical picture in power transmission process and frequency splitting phenomenon. Second, approximately constant voltage gain at frequency splitting point in a wide range of misalignment is analysed. Considering this frequency splitting characteristics of Magnetic resonant WPT, the maximum peak point tracking control methods for wide misalignment, maintaining constant output power is proposed. Finally, the corresponding simulation and experimental validation is given, demonstrating the feasibility of the control method. When the misalignment reached 40%, the fluctuation of the output voltage will be <4%, the DC–DC transmission efficiency will be enhanced to 80%.