Output Voltage Control of <i>LLC</i> Resonant Converter Based on Improved Linear Active Disturbance Rejection Control

The LLC resonant converter in the actual operation process is affected by the complex and changeable working conditions and faces many uncertain disturbances. It is difficult to achieve the desired dynamic performance. This article proposes an improved linear active disturbance rejection control (LADRC) strategy for output voltage control of LLC resonant converters. The control method embeds the adaptive frequency compensator into the extended state observer (ESO) to form an adaptive extended state observer, which improves the estimation ability of uncertain disturbance and optimizes the dynamic performance of the control system. In addition, this article provides a detailed design process, parameter tuning, and stability proof for the improved linear active disturbance rejection controller. Finally, load mutation and input voltage fluctuation experiments were conducted on various controllers on the established experimental platform, and the experimental results proved the effectiveness of the method.