LCC-S compensated variable inductor-based hybrid topology analysis for inductive power transfer system

Inductive power transfer (IPT) technology is widely used in the automobile industry, household electronics, and medical devices because of its numerous advantages. This manuscript proposes a novel hybrid topology for inductive power transfer (IPT) systems, combining the series–series (SS) and inductance–capacitance–capacitance–series (LCC-S) circuitries. The study introduces several key novelties to improve battery charging efficiency and reliability. Firstly, the hybrid topology achieves a load-independent zero phase angle (ZPA) condition at a constant resonant frequency, eliminating the need for frequency variation between constant current (CC) and constant voltage (CV) charging modes by introducing a tunable inductor and an AC switch. That results in simplified control circuit. In addition, it eliminates the need for variable resonant frequency control or coupling coefficient tuning to achieve CC and CV charging operations at a constant resonant frequency. Moreover, the proposed topology extends circuit lifespan and reliability by minimizing the number of capacitors required. Simulation analysis of a 2.4 kW prototype charging system was implemented in PLECS with MATLAB/Simulink to confirm the feasibility and operating performance of the proposed design. According to the results, the proposed topology successfully realizes stable CC and CV charging with ZPA condition at 85 kHz single resonant frequency even under different load conditions. The maximum power of 2.4 kW was achieved with 98.66% efficiency for an equivalent battery load of 67 Ω and a coupling factor of 0.3585. Additionally, a comparison review of CC/CV charging capability, control complexity, and cost-effectiveness between existing circuits and the designed topology are presented in the discussion of this paper.