Integral Cycle Mode Control for RF Inverters with Fast Dynamic Response and Wide-Range Soft Switching

This paper presents a novel control technique, Integral Cycle Mode (ICM), for RF inverters used in plasma generation applications. Unlike conventional methods, such as phase-shift, DC voltage, and frequency control, which involve trade-offs among dynamic response, soft-switching range, and hardware complexity, the proposed ICM method achieves fast dynamic performance and wide-range zero-voltage switching (ZVS) by alternating between Powering and Free-wheeling cells. Practical implementation of ICM on FPGAs is supported through applying a proposed interleaved algorithm to minimize plasma extinction risk. A power regulation model is derived and validated through LTspice simulations, showing strong agreement between calculated and simulated results. Experimental results confirm ZVS operation and stable output up to 7,000 W, both in continuous wave RF and pulsed RF operation, making ICM a practical and efficient solution for advanced semiconductor plasma processes.