Analysis and design of a S/PS compensated IPT system with constant current output

Load-independent constant current (CC) output with high-system efficiency is required in many cases of Wireless power transfer (WPT) applications. However, the existing topologies with CC output are hard to achieve both simple structure and enough design freedom. In this study, the series/parallel–series (S/PS) topology, which has three compensation capacitors, is presented to achieve CC output. The constant output current of the proposed S/PS topology is free from the constraint of the coils' self-inductance of the loosely coupled transformer (LCT). A thorough analysis of the proposed S/PS topology that implements CC and ZPA is provided. Besides, ZVS can also be obtained by reasonably setting the value of compensation capacitors. An experimental prototype with 50 V input voltage and 3 A output current is fabricated to validate the practicability and rationality of the proposed topology, and 92.18% power transfer efficiency is achieved. Furthermore, a design example with 2 A output current and the corresponding experimental results are provided to verify that the CC output of the proposed S/PS topology is free from the constraint of the LCT parameters. Finally, a comprehensive comparison with several existing topologies for CC output is conducted to reveal the advantages of the proposed S/PS topology.