基于自抗扰控制的电动汽车快速充电纹波抑制方法

摘要

电动汽车大功率快速充电采用直流供电方式,前级整流器产生的电压纹波不仅使蓄电池中出现过电压和过电流,降低电池寿命,还会降低后级DC-DC斩波器运行的稳定性,影响充电质量.因而,将整流器输出的电压纹波限制到规定的水平至关重要.以非线性、强耦合的三相桥式PWM整流器为研究对象,将自抗扰控制技术引入整流器控制中.对系统在两相同步旋转d-q坐标系下进行建模,并采用电压电流双闭环控制,根据直流侧输出电压与d轴电流的关系,将自抗扰控制器应用于电压外环控制中,利用PSCAD对系统进行仿真,与传统PI控制器的仿真对比表明,自抗扰控制器能够快速、准确地跟踪输出指令,降低输出电压纹波,提高系统的动态特性,且具有较好的抗负载扰动能力.%DC power supply mode is used for high power fast charging of electric vehicles,the voltage ripple generated by the former rectifier causes overvoltage and overcurrent in the battery,which can reduce the battery life and the operation stability of the rear level DC-DC chopper,and affect the quality of charging.Hence it is vitally important to restrict voltage ripple generated by rectifier below the level set.Taking nonlinear and strongly coupled three-phase bridge PWM rectifier as the research subject,this paper introduces the active disturbance rejection control technique into rectifier control.Under two-phase synchronous rotation d-q coordinate system,we establish the system model,and adopt voltage current double closed loop control.On the basis of the mathematical relation between DC-side output voltage and d-axis current,we use active disturbance rejection controller in voltage outer-loop control.The simulation results in PSCAD show that,compared with the traditional PI controllers,active disturbance rejection controller can track output instructions with high-speed and accuracy,reduce the voltage ripple,improve the dynamic characteristics of system and have good anti-load-disturbance performance.