Buck型变换器固定时间自适应控制

针对Buck型DC/DC变换器系统,提出一种固定时间自适应降压控制方法.首先,针对系统参数已知的情况,设计固定时间滑模面和控制器,保证系统输出电压误差在固定时间内收敛到平衡点,且其收敛时间上界与系统初始状态无关,仅由控制参数决定.针对电阻、电感等参数值受温度及外部干扰影响发生变化且无法准确获取的问题,进一步设计自适应更新律估计系统所有未知参数,并在此基础上设计固定时间自适应控制器,保证输出电压误差在固定时间内收敛到平衡点附近的邻域内.最后通过仿真和实验对比结果验证所提出控制方法的有效性.

Fixed-time adaptive control for Buck converters

A fixed-time adaptive control scheme is proposed for Buck DC/DC converters. Firstly, the fixed-time sliding mode surface and corresponding controller are developed for the system with known parameters to guarantee that the output voltage error converges to the equilibrium point within a fixed time, and the upper bound of the convergence time is independent of system initial states but determined by the control parameters. In the case that the value of some parameters including resistances and inductances is not precisely obtained under the effect of temperature and external disturbances, the adaptive update laws are designed for estimating all the unknown parameters of the Buck converters. Then, the fixed-time adaptive controller is proposed such that the output voltage error can converge to a small region around the equilibrium point within a fixed time. Simulation and experimental comparison results show the effectiveness of the proposed control scheme.