基于时变增益扩张状态观测器的逆变器系统自适应 super-twisting电压鲁棒控制

针对电压源逆变器系统中负载扰动和参数摄动, 本文提出了一种基于时变增益扩张状态观测器的自适应 super-twisting鲁棒电压控制新方法. 首先考虑负载扰动, 建立单相逆变器系统的动态模型, 进而考虑系统参数摄动, 通过引入非测量辅助状态变量, 将上述动态模型转化为只包含匹配扰动的状态方程; 其次, 设计时变增益扩张状态 观测器, 以实现对非测量辅助状态变量与包含负载变化和参数摄动等因素在内的集总不确定项的估计; 最后, 基于 此扩张状态观测器, 设计采用自适应super-twisting算法的滑模控制律, 以实现逆变器系统输出电压对其参考电压的 快速准确跟踪并增强系统鲁棒性. 仿真实验结果表明: 所提出的时变增益扩张状态观测器可在保证观测误差收敛 的同时, 有效抑制“初始微分峰值”现象; 采用自适应super-twisting算法的滑模控制策略可使逆变器系统输出电压 具有较高跟踪精度和较小总谐波失真率, 增强系统的抗干扰能力, 并降低控制输入信号“抖振”.

Robust voltage control for inverter system using time-varying gain extended state observer-based adaptive super-twisting algorithm

This study presents a new robust voltage control strategy using time-varying gain extended state observer (VGESO)-based adaptive super-twisting algorithm (ASTA) for voltage source inverter system with load disturbances as well as parametric perturbations. Firstly, taking load variations into consideration,the dynamic model of single-phase inverter system is established, and then, in the consideration of parametric perturbations, the above-mentioned dynamic model is transformed into the state equation which just includes matched uncertainty by introducing unmeasured auxiliary state variables. Secondly, a VGESO is designed to estimate the unmeasured auxiliary state variables and the lumped uncertainty including load variations and parametric perturbations simultaneously. Finally, on the basis of the VGESO, a sliding mode controller employing ASTA is synthesized so that the output voltage of inverter system is capable of tracking its reference value rapidly and accurately, and the robustness of the system can be enhanced. Simulation results illustrate that the proposed VGESO can not only guarantee the convergence of estimation error and but also effectively restrain the initial derivative peaking phenomenon. The proposed ASTA-based sliding mode controller enables the system output voltage to have high tracking accuracy and low total harmonic distortion, and enhances the ability of anti-disturbance for the system, reduces undesirable chattering of control input.