Abstract

The conventional model predictive control (MPC) method of the non-isolated two-stage AC-DC-DC converter has poor robustness and dynamic characteristics under conditions of model mismatch, external disturbance, and load disturbance. To solve this problem, a model-free predictive control method of the converter based on linear extended state observer (LESO) is proposed in this article. First, the ultra-local model of the two-stage converter is constructed to replace the mathematical model. Second, to improve the accuracy of the ultra-local model, LESOs are designed to estimate the uncertain part of each control loop. Third, the cost functions are adopted based on the deadbeat control method to achieve better dynamic performance. Finally, to further reduce the output current ripple, the carrier phase-shifting pulse width modulation is applied. The experimental results verify the high robustness and better control performance of the proposed method in a two-stage converter compared with the conventional MPC method.