有源前端LCL滤波器的谐振抑制技术研究

发布时间：2018-01-29 08:30

本文关键词： 有源前端 LCL滤波器谐振抑制有源阻尼无源阻尼　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：相比于传统的采用二极管整流或可控硅整流技术从交流电网获取直流母线电压的无源前端方案来说,采用有源前端(Active Front End,AFE)技术方案的变频器具有很多明显的优势,包括较低的网侧电流谐波污染、较高的功率因数、电网不稳定情况下仍然能够保持恒定的直流母线电压、可实现能量回馈的并网功能等。然而,在有源前端工作过程中,功率器件的开关动作会引入开关次及其整数倍次谐波电流分量。为了抑制这些电流谐波,要在变换器和电网之间加入滤波器。LCL滤波器以其体积小和高频衰减效果好等优势广泛地被应用作为变换器和电网的接口。然而LCL型滤波器属于三阶系统,频率响应在谐振频率处存在谐振尖峰及相位的跳变,这容易造成变换器振荡甚至不稳定,因此需要增加系统阻尼以消除谐振问题。本文在研究了国内外LCL滤波器谐振抑制方法的基础上,以一个5kWAFE系统为设计对象。首先,考虑到电网电流的IEEE标准及其他条件,对LCL滤波器参数进行了具体设计,并设计了最简单易行的无源阻尼方案。同时,根据实验中发现的实际电感的寄生电阻效应,设计了一种利用实际电感寄生参数设计无源阻尼的方案,并进行了无源阻尼的控制方案设计及评估。其次,在不考虑任何无源阻尼的条件下,设计了基于虚拟电阻法(电容电流反馈)和低通滤波器法的有源阻尼算法,并利用系统建模等手段,对系统进行了控制环设计以确保系统的静、动态特性良好,并对这些方法在稳定性、对电网阻抗的鲁棒性方面进行了评估,分析了各种方法的利弊。最后,在基于DSpace的实验平台上进行了部分设计方案的验证,仿真和实验的对比结果论证了这些设计方案的正确性。
[Abstract]:Compared with the traditional passive front-end scheme in which diode rectifier or thyristor rectifier is used to obtain DC bus voltage from AC network, active Front End is adopted. The frequency converter of AFE technology scheme has many obvious advantages, including lower harmonic pollution of grid side current, higher power factor, and the constant DC bus voltage can be maintained under the condition of power grid instability. However, in the process of active front-end operation, switching actions of power devices will introduce switching order and integer harmonic current components. The filter. LCL filter is widely used as the interface between converter and power grid because of its small size and high frequency attenuation effect. However, LCL filter belongs to the third order system. Tong. The frequency response has the resonance peak and the phase jump at the resonant frequency, which is easy to cause the converter oscillation and even instability. Therefore, it is necessary to increase the damping of the system to eliminate the resonance problem. Based on the study of the resonance suppression methods of the LCL filter at home and abroad, a 5kWAFE system is designed. First of all. Considering the IEEE standard and other conditions of power network current, the parameters of LCL filter are designed, and the most simple passive damping scheme is designed. According to the parasitic resistance effect of the actual inductor found in the experiment, a scheme is designed to design the passive damping by using the parasitic parameters of the actual inductor, and the control scheme of the passive damping is designed and evaluated. Secondly. Without considering any passive damping, the active damping algorithm based on the virtual resistance method (capacitive current feedback) and the low-pass filter method is designed, and the system modeling is used. The control loop is designed to ensure the static and dynamic characteristics of the system. The stability of these methods and the robustness of grid impedance are evaluated. The advantages and disadvantages of various methods are analyzed. Some of the design schemes are verified on the experimental platform based on DSpace, and the correctness of these design schemes is proved by the comparison between simulation and experiment.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761

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