AC-DC-DC变换器中间直流二次纹波电压抑制控制策略研究

发布时间：2018-03-09 15:25

本文选题：二次纹波电压抑制　切入点：反馈线性化　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：单相AC-DC-DC变换器,因为前级AC-DC变换器的功率脉动造成中间直流电压出现二倍工频纹波电压,传统的抑制该二次纹波的方法是在中间直流侧并联一个二次纹波LC滤波电路,用以滤除单相整流产生的二倍工频纹波电压。但是低频滤波器的系统体积和重量较大,成本较高,使得应用受限。本文主要研究无LC滤波电路的AC-DC-DC变换器二次纹波电压抑制控制方法。首先,分析了国内外直流电压二次脉动抑制研究现状,讨论了无LC滤波电路的AC-DC-DC变换器二次纹波电压产生机理。分别针对前级AC-DC变换器和后级DC-DC变换器分析了二次纹波电压的影响路径。分析发现,二次纹波电压会分别从控制环路和硬件前向通路,进而流通到硬件端口来影响变换器的输出,利用Matlab仿真,验证了该分析的正确性。其次,分别针对前级AC-DC变换器和后级DC-DC变换器设计了抑制二次纹波电压影响控制器。在前级AC-DC变换器采用瞬时电流控制的基础上,在电压控制环路增加陷波器来抑制二次纹波电压进入控制环路中,同时在电流内环增加输出电流扰动前馈通路来抑制剩余的谐波扰动。对于后级DC-DC变换器,在大信号模型基础上设计出反馈线性化控制器将原先多变量强耦合的非线性DC-DC变换器系统线性化,并实现输入输出电压解耦,为了进一步抑制DC-DC变换器输出电压纹波,增加了输出扰动前控制通路。同时,对于后级DC-DC变换器,设计了输入电压前馈的抑制方法。与传统比例积分及输入电压前馈的抑制方法的结果对比,验证了所提出的控制器的纹波电压抑制的有效性。最后,完成了前述给出的算法程序设计,搭建220W的单相三电平二极管箝位AC-DC-DC变换器验证性实验系统,进行稳态和瞬态实验。对比了所提控制方法与传统抑制控制方法和输入电压前馈的抑制方法,实验结果表明所提控制方法对系统的交流输入电流和直流输出电压能够取得更好的抑制效果。
[Abstract]:Single phase AC-DC-DC converter, because the power pulsation of the former AC-DC converter causes a double power frequency ripple voltage in the intermediate DC voltage, the traditional method to suppress the secondary ripple is to parallel a secondary ripple LC filter circuit at the middle DC side. It is used to filter the double power frequency ripple voltage generated by single-phase rectifier. However, the low frequency filter system is larger in volume and weight and higher in cost. In this paper, the secondary ripple voltage suppression control method of AC-DC-DC converter without LC filter circuit is studied. Firstly, the current research situation of DC voltage secondary ripple suppression is analyzed at home and abroad. The mechanism of secondary ripple voltage generation in AC-DC-DC converter without LC filter circuit is discussed. The influence paths of secondary ripple voltage are analyzed for the former AC-DC converter and the back stage DC-DC converter respectively. The secondary ripple voltage will affect the output of the converter from the control loop and the hardware forward path respectively, and then flow to the hardware port to influence the output of the converter. The correctness of the analysis is verified by Matlab simulation. The controller for suppressing the secondary ripple voltage influence is designed for the former AC-DC converter and the back stage DC-DC converter respectively. Based on the instantaneous current control of the former AC-DC converter, A notch is added in the voltage control loop to suppress the secondary ripple voltage from entering the control loop, and the output current disturbance feedforward path is added to the current inner loop to suppress the remaining harmonic disturbances. Based on the large signal model, a feedback linearization controller is designed to linearize the nonlinear DC-DC converter system with multivariable and strong coupling, and to decouple the input and output voltage. In order to further suppress the ripple of the output voltage of the DC-DC converter, a feedback linearization controller is designed. At the same time, the input voltage feedforward suppression method is designed for the rear stage DC-DC converter, which is compared with the results of the traditional proportional integral and input voltage feedforward suppression methods. The effectiveness of the proposed controller for ripple voltage suppression is verified. Finally, the algorithm program is designed, and a verification experiment system of 220 W single-phase three-level diode clamped AC-DC-DC converter is built. The steady-state and transient experiments are carried out. The proposed control method is compared with the traditional suppression control method and the input voltage feedforward suppression method. Experimental results show that the proposed control method can achieve better suppression effect on AC input current and DC output voltage of the system.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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