Modified parameter tuning method for LCL/P compensation topology featured with loadindependent and LCT-unconstrained output current

Inductive power transfer (IPT) has attracted a lot of attention in recent 30 years due to its advantages of convenience, safety, reliability and weather proof. This study proposes a modified parameter tuning method for primary inductor-capacitorinductor, secondary parallel (LCL/P) compensation topology, which provides the characteristic of excellent constant current output (CCO). This characteristic is analysed on the basis of inductor-capacitor(LC) and capacitor-inductor (CL) resonant tanks. To lower the voltage stresses over capacitors and current stresses through inductors, the stress-based optimisation is conducted. The sensitivity of CCO characteristic with respect to the normalised deviation of compensation parameters is analysed; therefore, the performance of LCL/P compensated IPT system in practical scenarios can be fully understood. The loosely coupled transformer (LCT) is specially designed since it has a significant impact on system efficiency, component stress, power density etc. An exhaustive search algorithm is employed to find the optimal dimensions of the LCT. A 100 W LCL/P compensated IPT prototype is fabricated. The measured end-to-end efficiency, from DC input to DC output, is as high as 92.8%. The output current only increases by 2.02% when the load decreases by half. All experiment results agree well with the theoretical analysis.