三相电压型PWM整流器的滑模变结构无源控制

摘要

Better dynamic and static performance is needed for the three-phase voltage source PWM rectifier in appli-cations. To deal with the nonlinearity and strong coupling characteristic of the rectifier, the paper proposes a sliding-mode variable structure and passivity control strategy. The sliding-mode variable structure control is used in the volt-age outer-loop, and the passivity control is used in the current inner-loop. In sliding-mode control, the error of the output direct voltage is used as the state variable to construct switching surface with exponential damping. In passivity control, the state errors are used to build the energy storage function while the function is defined as the Lyapunov function, which makes the system rapidly converge to the desired stable equilibrium point with damping injection. The passivity controller is designed based on the astringency condition of the error storage function to achieve decoupled control of each variable. Simulation studies are developed in PSCAD/EMTDC. Result comparison with nested-loop PI control shows the strategy presents good dynamic and steady performance with strong robustness.%三相电压型PWM整流器在应用中需要更加优良的动、静态性能。针对整流器的非线性强耦合特点，提出了一种滑模变结构无源控制算法。算法中电压外环采用滑模变结构控制，电流内环采用无源控制。滑模控制中以整流器输出直流电压误差为状态变量构造指数衰减律切换面。无源控制中采用状态误差构造能量存储函数并以误差存储函数为Lyapunov函数，通过注入阻尼使系统快速收敛到期望稳定平衡点。根据误差存储函数的收敛条件设计了整流器的无源控制器，实现了各变量的解耦控制。用PSCAD/EMTDC软件进行仿真分析。与双闭环PI控制对比，仿真结果表明该控制策略具有良好的动、静态性能和鲁棒性。