三相 PWM变换器的负载自适应控制

摘要

三相 PWM变换器因结构相对简单，开关器件电压应力低，效率高等优点得到广泛应用。三相 PWM变换器一般采用双闭环控制，控制器采用 PI 控制方法，但传统 PI 控制方法存在参数不易整定且负载变化时适应性差的问题。针对这些问题，本文提出在三相 PWM变换器电压外环和电流内环分别采用负载自适应控制及反馈线性化控制方法。本文方法避免了传统 PI 控制参数调整困难费时的问题，同时改善了系统性能。仿真及实验结果表明，与传统 PI 控制和精确反馈线性化控制方法相比，本文方法控制参数少，易于选择，在负载发生变化时，输出电压波动小、恢复时间短，具有更强的适应能力。%The three-phase PWM converter is widely used due to the advantages of its simple topology,low voltage stress on switching devices and high efficiency.Conventionally,double closed-loop PI (Proportional-Integral)controllers are used for three-phase PWM converters.However,PI controllers have two main problems:difficulty to adjust the parameters of the controller and lack of adaptability to the system parameters variations.To deal with these problems,a load-adaptive control method and a feedback linearization control method are proposed for the voltage outer-loop and current inner-loop control of the three-phase PWM convert-er,respectively.The proposed method avoids the difficult and time-consuming parameters adjustment problems of the conventional PI controllers design,and improves the performance of the system.The simulation and experiment results show that,compared to the traditional PI control and the existing feedback linearization control method,the proposed control method uses less adjustable param-eters which are easy to be chosen,and provides less output voltage perturbation,less recovery time and stronger adaptivity with re-spect to load variations.