Phase Locked Loop Based Soft Switching Implementation of Class D Series Resonant Inverter

Soft switching techniques are critical to minimize switching losses and improve system efficiency in power electronics systems. This study uses a CD4046 based phase locked loop (PLL) control system to optimize the zero current switching (ZCS) performance of a Class D series resonant inverter under dynamic load conditions. The system guarantees soft switching conditions by automatically monitoring the resonant frequency over a broad range of 27 kHz to 41 kHz. In the experimental study, the resonant frequency of the series resonant inverter is dynamically adjusted using a parallel connected capacitor bank, facilitating the assessment of the PLL system’s adaptive performance. The results demonstrate that the system can effectively lock onto the resonant frequency, rapidly adapting to changes in load impedance while consistently maintaining zero current switching conditions.