Balanced Design Method for LCL/LCL Compensation Achieving Wide Load Range and High Misalignment Tolerance

Inductive power transfer (IPT) technology is widely applied in autonomous underwater vehicles, electric ferries, electric fishing boats, etc. In these scenarios, constant output voltages need to be provided considering misalignment tolerance and load variations. This paper presents a balanced design for LCL/LCL compensation. Similar to the L-S/S-L compensation introduced in [10], LCL/LCL compensation using balanced design can achieve nearly unity power factor with wide load range and high misalignment tolerance by adjusting the operating frequency. Different from L-S/S-L compensation in [10], the balanced LCL/LCL compensation in this paper is more suitable for cases where the coupling coefficient is higher than 0.45. In these higher coupling coefficient application scenarios, the selection of LCL/LCL compensation can result in smaller compensation inductance. Lower inductance means lower cost and higher efficiency in practical terms. The proposed method is verified by simulation experiments. Simulation experiments show that nearly unity power factor and constant voltage output are achieved by frequency modulation with load and coupling variations. Zero voltage switching (ZVS) is also achieved by slightly reducing the primary coil inductance.