Optimal Impedance Design for Dual-Branch High-Frequency Inverter Based on Active Regulation and Passive Projection

High-frequency inverters often need to operate under dynamically varying loads, while the inverter structure allows only very narrow loads. In this article, an optimal impedance design method for dual-branch high-frequency inverter is proposed, which maintains an ideal impedance value at the inverter side under dynamic loads by active parameter regulation and passive projection. The method decouples the impedance compression and impedance matching into two separate steps, the control parameters and circuit parameters are designed according to analytical formulas, which ensures the impedance compression effect and achieves accurate and fast numerical calculation at the same time. A 13.56-MHz 75-W inverter prototype is built, the load varying in an 6500 Ω2 area can be compressed into 50 Ω2 area centered on ideal impedance 5 + j7Ω, which helps Class E inverters to maintain a ZVS state under wide range of load. A fast real-time response within 40 μs is guaranteed.