基于滑模变结构的Vienna整流器控制研究

Research on Control of Vienna Rectifier Based on Sliding Mode Variable Structure

三相三电平Vienna整流器由于具有功率密度高、开关电压应力小、网侧电流谐波小等优势,在数据中心供电系统等交直流混合供电电源中获得广泛应用。然而三相Vienna整流器并网电流性能对于控制器参数取值依赖性强,不合理的取值往往导致网侧电流畸变且系统抗干扰性差。为有效改善并网电流动静态性能,提出一种新型的基于双闭环滑模变结构的载波SVM控制策略,进一步采用了一种改进型幂次趋近律并给出了中点电位直流波动抑制策略。为验证所提滑模控制SMC(sliding mode control)方案的正确性,构建了完整的仿真与实验测试模型,给出了详细的理论分析与设计方案,仿真与实验结果表明所提控制策略可有效改善并网网侧电流动静态性能,同时保证了直流侧中点电位均衡。

Owing to its advantages such as high power density,low switch voltage stress and small grid current harmonic,the three-phase three-level Vienna rectifier has been widely applied to AC/DC hybrid power supplies including the data center DC power supply.However,the grid current performance of the three-phase Vienna rectifier strongly depends on the controller parameters,and unreasonable parameter values may often deteriorate the grid current,causing a worse anti-interference performance of the system.To effectively improve the static and dynamic performance of grid current,a novel kind of carrier-SVM control strategy based on the double closed-loop sliding mode variable structure is put forward.Furthermore,a modified exponential reaching law is adopted,and the neutral voltage DC fluctuation suppression strategy is given.To verify the correctness of the proposed sliding mode control(SMC)scheme,a complete simulation and experimental test model is established,and the detailed theoretical analysis and design scheme are given.Simulation and experimental results show that the proposed control strategy can effectively improve the dynamic and static performance of grid current while keeping the neutral voltage on DC side balanced.