A simplified model-based nonlinear control with fast response and simple design flow for HB-LLC resonant converter

LLC resonant converters have attracted much attention for its characteristics of high efficiency and high-power density in recent years. Yet, with the diversity of application needs such as photovoltaic power generation and electric vehicles, traditional control solutions have gradually been unable to meet the increasing requirements, such as fast response to parameters perturbations. Besides, LLC converter is a high-order nonlinear system, and it adds complexity to controller design. In order to solve these issues, taking the HB-LLC converter as an example, this paper presents a simplified model-based nonlinear control with fast response and simple design. The proposed controller is based on a second-order model of LLC circuit, and the reverse design idea of the backstepping method is used to simplify the controller design. An experimental platform is built, and the results show that compared with PID control and linear active disturbance rejection control (LADRC), the proposed method has much smaller voltage undershoot (approximately 53.1% of PID and 68.4% of LADRC) and shorter settling time (approximately 27.8% of PID and 39.3% of LADRC) under input voltage change. This paper presents a controller design method for HB-LLC converter, which has a clear and simple design flow and also has good dynamic performance. Specifically, this control method combines a simplified LLC model and backstepping and sliding mode control. image