三相PWM整流器前馈与滑模变结构控制研究

在两相旋转坐标系下对三相电压型PWM整流器进行建模分析。针对双闭环PI控制策略抑制负载扰动及电网电压波动能力差，以及系统动态响应慢等问题，提出了负载电流前馈策略来提高系统抗负载波动能力。并且电流环采用基于PID趋近率的滑模变结构控制策略来满足前馈控制策略对内环响应速度的要求，并提高系统动态性能以及鲁棒性，PID趋近率可以有效抑制传统变结构的抖振问题。应用Matlab/Simulink软件进行仿真，并以DSP TMS320X2812为核心搭建优化控制器的三相VSR实验平台，进行仿真及实验验证。结果显示本文所提出控制方法可有效抑制负载变化、电网电压波动以及其它干扰所对直流电压稳定性的影响，具有很强的鲁棒性，动态响应速度快且性能稳定。

Design on Feed-Forward and Variable Structure Control for Three-phase Voltage Source PWM Rectifier

Analyzed the basic principle of three-phase voltage source PWM rectifier and established the model under two-phase rotating coordinate system. To improve the function of traditional double closed-loop PI control strategy, for insurance load disturbance and voltage fluctuation has a great influence on the DC bus voltage, as well as dynamic response problem. This paper proposed load current feed forward strategy to weaken load disturbance and improve robustness. Current loop use sliding mode control based on PID trending law strategy to satisfy the requirement of load current feed-forward and improve robusness. PID trending law can minimize the vibration of sliding mode control and can regulate reaching time. Simulation with Matlab/Simulink. DSP TMS320X2812 was used for building an optimal controller of VSR platform to conduct experiments. Results show the proposed method can effectively eliminate the DC bus voltage fluctuation, which caused by load change and grid voltage fluctuation, fast dynamic response and robustness.