直流降压变换器的降阶扩张状态观测器与滑模控制设计与实现

Design and implementation of reduced-order extended state observer and sliding mode control for DC-DC buck converter

本文针对直流降压变换器的负载电阻扰动和输入电压变化等系统不确定因素对输出电压的影响,提出了基于降阶扩张状态观测器的滑模控制方法(SMC+RESO).首先设计降阶扩张状态观测器对系统状态,负载电阻扰动和输入电压变化进行估计,然后基于估计值利用滑模控制技术设计控制器,实现对直流降压变换器系统给定电压跟踪的快速性和准确性.值得注意的是,不同于文[1]所提出的基于扩张状态观测器的滑模控制方法(SMC+ESO),本文所提出的方法采用降阶扩张状态观测器,实现简单,且无需电流传感器,减小了实际应用的成本.利用Lyapunov稳定性定理从理论上证明了所设计的控制器可以保证闭环系统的稳定性.仿真和实验结果表明,与已有的基于扩张状态观测器的滑模控制方法相比,所提出的控制方法更好地改善了系统的跟踪性能和对干扰和不确定性的鲁棒性能,且减少了成本,但是牺牲了系统稳态性能.

Aiming to the influence of system uncertainties such as load resistance disturbances and input voltage changes of the DC–DC buck converter on the output voltage,a sliding mode control method based on a reduced-order extended state observer(SMC+RESO)is proposed.First,a reduced-order extended state observer is designed to estimate the state of the system,disturbance of load resistance,and input voltage variation,then the controller is designed based on the estimated value using the sliding mode control technology to achieve the rapidity and accuracy tracking of the given voltage of the DC–DC buck converter system.It is worth noting that unlike the sliding mode control method based on the extended state observer proposed by[1],the method proposed in this paper uses a reduced-order extended state observer,which is simple to implement and does not require a current sensor,which reduces the cost in practical applications.The Lyapunov stability theorem is used to prove theoretically that the designed controller can guarantee the stability of the closed-loop system.Simulation and experimental results show that compared with the sliding mode control method based on the extended state observer(SMC+ESO).The proposed control method improves the tracking character and robustness to disturbances and uncertainties better,but sacrifices the steady state performance.