Linear Active Disturbance Rejection Control of LLC Resonant Converters for EV Chargers

LLC resonant dc-dc converters have been increasingly adopted in electric vehicle (EV) charger applications because of high efficiency and power density. However, multiple disturbance factors and complex dynamic characteristics make the high performance control still a challenging problem. A new linear active disturbance rejection control (LADRC) strategy for the LLC converter is proposed to improve the dynamic performance and suppress the influence of internal and external disturbances on the output voltage in this paper. First, based on the extended describing function (EDF) method, the mathematical model of the LLC converter is established. Then, a second order LADRC controller is designed to eliminate various disturbances. In addition, a compensation function is proposed to reduce the computational burden of the linear extended state observer(LESO). Finally, simulations compared with traditional PI controller are used to show the feasibility and effectiveness of the proposed strategy.