基于非线性扰动观测器的三相PWM整流器滑模控制

Nonlinear disturbance observer-based sliding-mode control for three-phase PWM rectifiers

针对交流微电网中三相PWM整流器的运行状态易受负载扰动、滤波电容参数摄动影响的问题,本文提出一种基于非线性扰动观测器的三相PWM整流器滑模控制方法。首先,将负载扰动、滤波电容参数摄动等视为集总扰动,构建电压环非线性模型。其次,设计非线性扰动观测器,实现集总扰动的在线估计。为实现主动抗干扰控制和滑模抖振抑制,将估计的集总扰动引入到滑模面中,得到了一种含有扰动估计的新型滑模面。最后,基于滑模控制理论设计电压外环滑模控制器,并采用Lyapunov稳定性理论对其进行了稳定性证明。动态性能测试结果表明,非线性扰动观测器能够快速、准确地对集总扰动进行估计;与双环PI控制相比,所提控制的过渡过程时间减少了60%,电压跌落量减少了54%;滤波电容参数变化时,所提控制的动态性能保持良好。稳态性能测试结果表明,与传统滑模控制和双环PI控制相比,所提控制的电流总谐波畸变率分别减少了70%和44%,同时滑模抖振得到了有效地抑制。测试结果证明了所提控制方法的强抗负载扰动能力和良好的滤波电容参数鲁棒性。

Aiming at the problem that the operation state of three-phase PWM rectifier in AC microgrid is easily affected by load disturbance and filter capacitor parameter perturbation,a sliding mode control method of three-phase PWM rectifier based on nonlinear disturbance observer is proposed in this paper.Firstly,the load disturbance and filter capacitor parameter perturbation are regarded as lumped disturbances,and the nonlinear model of voltage loop is constructed.Secondly,a nonlinear disturbance observer is designed to realize the online estimation of lumped disturbances.In order to achieve active anti-interference control and sliding mode chattering suppression,the estimated lumped disturbance is introduced into the sliding mode surface,and a new sliding mode surface with disturbance estimation is obtained.Finally,the voltage outer loop sliding mode controller is designed based on the sliding mode control theory,and the stability is proved by Lyapunov stability theory.The dynamic performance test results show that the nonlinear disturbance observer can estimate the lumped disturbance quickly and accurately.Compared with the double-loop PI control,the transition process time of the proposed control is reduced by 60%,and the voltage drop is reduced by 54%.When the filter capacitor parameters change,the dynamic performance of the proposed control remains good.The steady-state performance test results show that compared with the traditional sliding mode control and the double-loop PI control,the total harmonic distortion of the current of the proposed control is reduced by 70%and 44%respectively,and the sliding mode chattering is effectively suppressed.The test results show that the proposed control method has strong anti-load disturbance ability and good robustness of filter capacitor parameters.