三相电压型PWM整流器的非线性现象研究

发布时间：2018-12-17 08:30

【摘要】：由于三相电压型PWM整流器具有输入单位功率因数、高质量的直流电压和低失真输入电流等优越的性能，，其应用日益广泛。而在三相电压型PWM整流器的实际运行中，会出现电压突然崩溃、控制系统间歇振荡、不明电磁噪声等非正常工作现象，因此，从三相电压型PWM整流器属于非线性系统这一本质出发，利用非线性动力学研究三相电压型PWM整流器的不规则现象，有助于深入了解三相电压型PWM整流器的运行规律，对三相电压型PWM整流器的推广应用具有实际意义。为了阐述三相电压型PWM整流器发生直流侧电压崩溃现象的机理，本文基于电压与电流的双闭环控制策略建立了三相电压型PWM整流器的闭环模型，然后针对不同类型的负载，运用非线性动力学理论分析了负载参数大小对电压崩溃现象的影响，最后进行了仿真和实验验证。本文做的主要工作包括以下几个方面： 1.对采用电压外环和电流内环双环控制的三相电压型PWM整流器建立了闭环模型，然后分别从系统能量守恒和PWM过调制两个不同角度分析了三相电压型PWM整流器发生直流侧电压崩溃现象的机理。 2.对带纯电阻负载的三相电压型PWM整流器，利用雅克比矩阵法推导雅克比矩阵特征根与负载电阻R和直流侧滤波电容C之间的关系，得到直流侧电压崩溃时R和C的临界值。 3.对带阻感负载的三相电压型PWM整流器建立闭环模型，通过计算不同负载电阻R对应的雅克比矩阵特征根，得到带阻感负载的三相电压型PWM整流器的稳定工作区域；进而基于所建立的闭环模型，画出负载电阻R突变时各个状态变量的变化轨迹图，得到直流侧电压崩溃时的临界电阻值。 4.与带阻感负载的三相电压型PWM整流器的分析类似，对带反电动势负载的三相电压型PWM整流器进行分析，得到直流侧电压崩溃时的临界电阻值和临界反电动势值。 5.上述分析结果均用Matlab/Simulink进行了仿真验证，此外还基于RT-LAB半实物仿真平台搭建三相电压型PWM整流器的实验电路，进行相关的实验，验证电压崩溃现象。
[Abstract]:The three-phase voltage-source PWM rectifier is widely used because of its excellent performance such as input unit power factor, high quality DC voltage and low distortion input current. But in the actual operation of three-phase voltage-source PWM rectifier, there will be sudden voltage collapse, intermittent oscillation of control system, unknown electromagnetic noise and other abnormal working phenomena. Starting from the fact that three-phase voltage-source PWM rectifier belongs to nonlinear system, the irregular phenomenon of three-phase voltage-source PWM rectifier is studied by nonlinear dynamics, which is helpful to understand the running rule of three-phase voltage-source PWM rectifier. It is of practical significance for the popularization and application of three-phase voltage source PWM rectifier. In order to explain the mechanism of DC side voltage collapse in three-phase voltage-source PWM rectifier, the closed-loop model of three-phase voltage-source PWM rectifier is established based on the double-closed-loop control strategy of voltage and current. The influence of load parameters on voltage collapse is analyzed by using nonlinear dynamics theory. Finally, the simulation and experimental results are carried out. The main work of this paper includes the following aspects: 1. The closed-loop model of three-phase voltage-source PWM rectifier controlled by voltage outer loop and current inner loop is established. Then the mechanism of DC side voltage collapse of three-phase voltage-source PWM rectifier is analyzed from two different angles of energy conservation and PWM overmodulation. 2. For a three-phase voltage-source PWM rectifier with pure resistor load, the relationship between the characteristic root of Jacobian matrix and the load resistance R and the DC side filter capacitance C is derived by using the Jacobian matrix method, and the critical values of R and C when the DC side voltage collapses are obtained. 3. The closed-loop model of three-phase voltage-source PWM rectifier with resistive load is established. The stable working area of three-phase voltage-source PWM rectifier with resistive load is obtained by calculating the characteristic roots of Jacobis matrix corresponding to different load resistors. Then, based on the closed-loop model established, the trajectory diagram of each state variable when the load resistance R changes is drawn, and the critical resistance value when the DC side voltage collapses is obtained. 4. Similar to the analysis of three-phase voltage-source PWM rectifier with resistive load, the three-phase voltage-source PWM rectifier with backEMF load is analyzed, and the critical resistance and critical back-EMF value of DC side voltage collapse are obtained. 5. In addition, the experimental circuit of three-phase voltage-source PWM rectifier is built based on RT-LAB hardware-in-the-loop simulation platform, and the related experiments are carried out to verify the phenomenon of voltage collapse.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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