1. College of Information and Control Engineering China University of Petroleum (East China) Qingdao 266580 China; 2. School of Mechanical and Electrical Engineering Qingdao Huanghai University Qingdao 266427 China
Abstract:The conventional PI voltage control of buck converter cannot obtain satisfying dynamic responses and anti-disturbance ability under parameter variations and load disturbances. Moreover, the traditional sliding mode control is often designed based on continuous-time voltage single loop, resulting in discretization stability problems and poor voltage dynamic performance in comparison to double closed-loop control. Thus, this paper proposes a robust discrete integral sliding mode (DISM) voltage control scheme for Buck converters. Firstly, a discrete voltage model with lumped disturbance is rebuilt while preserving the current inner loop in the traditional double closed-loop control, and a novel global-robustness DISM voltage controller is designed to improve the dynamic quality and anti-disturbance ability of the output voltage. Then, a ‘delay disturbance estimation’ strategy is used to estimate and compensate the lumped disturbance online, achieving the engineering implementation of the controller and the chattering suppression of sliding mode control. Finally, the stability analysis and parameter design procedures of the proposed controller are given. Its superiority is verified by comparative simulations and experiments with conventional PI voltage control.
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