Frequency feedforward control of LLC resonant converter based on simplified time-domain model

The LLC resonant converter, when controlled by a traditional linear regulator PI controller, exhibits suboptimal dynamic response performance. In the event that the dynamic response is accelerated, the sudden adjustment of the voltage loop can cause a surge in resonant current. This has the potential to result in damage to the MOSFET and other hardware. The present paper puts forth a frequency feedforward control strategy based on a simplified time-domain algorithm. The strategy first utilizes a simplified time-domain model of the converter to predict the output. It then designs a resonant current cost function using the constructed simplified time-domain model. Finally, it feeds the model into the PI controller to obtain appropriate control signals. This approach is designed to enhance the dynamic performance of the converter without compromising the integrity of the hardware circuitry. The proposed control strategy is then subjected to empirical validation through a series of experiments.