Buck型变换器自适应有限时间降压控制算法研究

An Adaptive Finite-time Control Algorithm for Buck Converter Systems

针对负载未知情况下Buck型DC-DC变换器系统,基于有限时间控制技术和自适应控制技术,提出了一种新的快速降压控制算法.首先,基于时间尺度变换,对系统的平均状态空间方程进行变换;然后,利用饱和有限时间控制理论设计出一类新的快速降压控制算法,以实现输出电压在有限时间内收敛到参考电压.由于控制器设计过程中考虑了饱和约束条件,使得变换器的占空比函数满足0到1之间的约束条件.对于负载未知情况,设计了有限时间观测器以估计未知负载,最终得到自适应式的有限时间控制算法.与PI控制结果进行了仿真对比,验证了所提出的控制算法既具有快速的调节性能,又具有较强的抗负载变化性能.

For Buck DC-DC converter systems with unknown load variations, a new voltage regulation control algorithm is proposed by using the techniques of finite-time control and adaptive control. First, a time-scale transformation is used for the average state space model of the Buck converter system. Then,based on the saturation finite-time control theory, a new fast voltage regulation control algorithm is designed which can guarantee that the output voltage converges to the reference voltage in a finite time. Because the saturation constraint is considered during the controller design, the duty ratio function of the converter satisfies the constraint between 0 and 1. For an unknown load, a finite-time convergent observer is designed to estimate the unknown load. Finally, an adaptive finite-time control algorithm is developed. Compared with the PI control algorithm,numerical simulations show that the proposed algorithm has a faster regulation performance and stronger performance on loadvariation rejection.