VIENNA整流器PI滑模混合控制与晶闸管软启动研究

Research on PI Sliding Mode Hybrid Control and Thyristors Soft Start of VIENNA Rectifier

针对三相VIENNA整流器采用传统PI双闭环控制时系统参数设计困难、鲁棒性差的问题,提出了一种滑模控制(sliding mode control,SMC)策略。该控制策略外环采用滑模控制器,提高了系统的动态性能和鲁棒性,内环采用PI控制器满足系统稳定性要求并简化了控制系统。此外,为抑制VIENNA整流器的启动冲击电流,提出了一种两段式软启动控制方法。首先,使用晶闸管对直流母线电容进行预充电;其次,在PWM整流过程将直流母线电压给定值设定为以一定斜率增长至期望值的斜坡信号;最后切入直流侧负载。仿真结果表明:采用所设计PI滑模混合控制策略的VIENNA整流器,具有良好的动、稳态性能以及鲁棒性;所提出的两段式软启动控制方法具有良好的抑制冲击电流能力。

Aiming at the problem that the three-phase VIENNA rectifier adopts the traditional PI double closed-loop control,the system parameters are difficult to design and the robustness is poor.A sliding mode control(SMC)strategy is proposed.The outer loop of the control strategy adopts a sliding mode controller,the dynamic performance and robustness of the system are improved.The inner loop uses the PI controller to satisfy the system stability requirements and simplifies the control system.In addition,in order to suppress the startup inrush current of the VIENNA rectifier,a twostage soft start control method is proposed.First,the DC bus capacitors are prechargedusing thyristors.Secondly,in the PWM rectification process,the DC bus voltage reference value is set to a ramp signal that increases to a desired value with a certain slope,and finally cuts into the DC side load.The simulation results show that the VIENNA rectifier with the designed PI sliding mode hybrid control strategy has good dynamic and steady performance and robustness.The proposed two-stage soft start control method has good ability to suppress the inrush current.