Research on Constant‐Frequency Reconstruction LCC/S‐S and I‐Shaped Multi‐Transmitter Coil Structure in Wireless Power Transfer Systems

ABSTRACT In new energy vehicle wireless power transfer systems, horizontal misalignment between transmitter and receiver coils changes mutual inductance, causing large current and voltage fluctuations during lithium battery charging and endangering system safety. To address this potential issue, a system integrating constant‐frequency reconstruction LCC/S‐S and an I‐shaped multi‐transmitter coil structure is proposed in this paper. This system ensures that constant output current and voltage are maintained even when coil misalignment or load variations occur. First, a constant‐frequency reconstruction LCC/S‐S equivalent model is constructed and analyzed, with mutual inductance found to be crucial for maintaining constant current and voltage. Thus, an I‐shaped multi‐transmitter coil structure is simultaneously proposed to suppress fluctuations. Then, the mutual inductance characteristics of the coil structure were analyzed via a mutual inductance calculation method, and the mutual inductance was optimized to derive coil structure parameters and core structure parameters that satisfy the design criteria. Finally, a 700.0 W prototype is developed. It is shown by simulations and experiments that with receiver misalignment up to 53.0% of the transmitter coil's side length, mutual inductance fluctuation is within 4.7%, constant‐voltage fluctuation within 4.3%, and constant‐current fluctuation within 4.5%, with stable power transfer needs met.