Design of LLC resonant circuit for controlling plasma energy distribution using bias waveform

In response to the requirement for controllability of ion energy distribution in plasma processing technology, this study proposes a pulse waveform generation method based on the LLC resonant converter. By leveraging the adjustable gain characteristic of the LLC circuit near the resonant frequency and combining multi - phase rectification and multi - phase LLC parallel technology, a pulsed bias output with independently adjustable frequency and amplitude and flexible waveform control is achieved. The system adopts a hybrid control architecture of DDS + STM32. Combining multi - phase LLC parallel and interleaved rectification technology, it significantly increases the ripple frequency and dynamic response speed while boosting the output power. Simulation and experimental results show that the proposed scheme can achieve continuous adjustment of the output voltage amplitude from 30% to 120% within the frequency modulation range of 13 kHz-41 kHz. Under multi - phase output, the ripple frequency is increased to 3-7 times that of the fundamental wave, providing an effective hardware implementation approach for the active control of plasma energy distribution.