For the wireless charging systems for electric vehicles (EVs), the misalignment phenomenon due to inaccurate parking is the most significant issue, which causes non-negligible negative impacts on the power efficiency and amount. That is because the positional misalignment between coils leads to significant changes in parameters such as mutual inductance, which in turn causes dramatic fluctuations in the system’s output voltage and efficiency. It potentially prevents the system from functioning correctly or even damages it. Therefore, research on the anti-misalignment capability of EV wireless charging systems is crucial. Current research focuses on high-frequency inverter control, coupling mechanism design, and compensation topology design. However, these methods fail to maintain a constant output voltage when both coil misalignment and large variations in load occur. This paper proposes a novel hybrid compensation topology based on the QRQP coil.

This paper uses finite element simulation software to investigate a QRQP coil and its misalignment and coupling characteristics. To reduce output voltage fluctuations caused by coil misalignment and large variations in load, a novel hybrid topology is introduced based on the QRQP coil. This topology leverages the principle of opposing output characteristics between S-LCC, LCC-S, LCC-LCC, and SS topologies. Detailed design guidelines for the parameters and optimization strategies are proposed. Meanwhile, the system’s anti- misalignment capability under different parameter selections is analyzed. Finally, optimal system parameters are selected and analyzed. The optimized system can maintain a constant output voltage under various misalignment angles and load variations within a specific range. When the receiving coil is removed, the primary-side current can be effectively limited, which ensures the system's safety.

The proposed topology has been validated through a 1 kW laboratory prototype. Experimental results show that when the load resistance varies from 20 Ω to 100 Ω, the system maintains output voltage fluctuations of less than 5% under X-axis misalignment from -140 mm to +140 mm, Y-axis misalignment from -105 mm to +105 mm, and diagonal misalignment along the XY-axis from -200 mm to +200 mm. When the load resistance varies from 20 Ω to 100 Ω and the coils’ vertical distance changes from -35 mm to 70 mm, the output voltage fluctuation can be kept within 8%. Furthermore, since the system exhibits capacitive behavior after misalignment and has no compensating inductance, it can operate with high efficiency. Analysis under extreme conditions shows that when the receiving coil is removed, the optimized hybrid topology effectively limits the primary-side current surge, preventing system damage.

The following conclusions can be drawn. (1) The proposed optimization theory for the novel hybrid topology is consistent with the experimental results. (2) The optimized hybrid compensation topology based on the QRQP coil can effectively reduce output voltage fluctuations when coil misalignment and large variations in load occur simultaneously. (3) When removing the receiving coil, the optimized hybrid topology effectively limits the primary-side current surge, preventing system damage.