电网不平衡条件下三相PWM整流器控制及并联研究

发布时间：2018-05-25 01:29

本文选题：三相PWM整流器 + 电网不平衡　；参考：《东北大学》2014年硕士论文

【摘要】：三相PWM整流器具有直流电压可控,网侧电流正弦化和单位功率运行等优良的特性,是电力电子领域研究的热点之一。整流器并联运行可以增加系统的冗余度,提高功率输出,非常适用于大功率场合。但整流器并联系统会产生环流,而且实际上电网也经常会出现不平衡状态,这些问题会造成网侧电流不平衡,降低负载效率,本文针对整流器在电网不平衡条件下和并联运行的情况下存在的交流侧电流不稳定问题和并联环流问题展开研究。通过阅览国内外的大量文献综述了PWM整流器及其并联控制的发展现状,分别分析三相PWM整流器在不平衡条件下和并联运行时的工作原理及环流特性,建立整流器在三相静止坐标系和旋转坐标系下的数学模型,整流器并联系统环流数学模型,并在此基础上建立了整流器双闭环控制系统。针对三相PWM整流器在电网不平衡状态时会造成交流侧电流畸变的问题,本文提出了并联控制控制方法,在不平衡条件下采用两台整流器进行控制,一组整流器产生正序电流,另一组产生负序电流,经过并联控制实现了整流器容量扩充和谐波抑制的效果。三相整流器并联运行时会产生多个路径的环流,为了消除环流的影响提出了协调控制策略,使整流器之间的负序和零序环流得到抑制,并通过控制正序电流分量实现负载功率均分。用Matlab软件搭建了三相PWM整流器在电网不平衡条件下的及并联控制仿真模型,验证了文中各控制策略的正确性。最后结合理论推导和仿真确定了符合实验要求的各硬件参数与型号,设计各驱动电路与调理电路,以TMS320F2812DSP为核心构建实验平台,设计软件流程并在CCS编译软件中用C语言编写软件程序。经过仿真分析与实验调试,较好的实现了电网不平衡条件下PWM整流器网侧电流与直流侧电压控制。
[Abstract]:Three-phase PWM rectifier has the advantages of DC voltage controllable, grid side current sinusoidal and unit power operation, etc. It is one of the hot research topics in power electronics field. Rectifier parallel operation can increase the redundancy of the system, improve the power output, very suitable for high power situations. But the rectifier parallel system will produce circulation, and in fact, the power network will often appear unbalanced state, these problems will lead to the grid side current imbalance, reduce load efficiency, In this paper, the AC side current instability and the parallel circulation problem of rectifier under the condition of unbalanced power network and parallel operation are studied. The development of PWM rectifier and its parallel control are reviewed by reviewing a large number of literatures at home and abroad. The working principle and circulation characteristics of three-phase PWM rectifier under unbalanced conditions and parallel operation are analyzed respectively. The mathematical model of rectifier in three-phase static coordinate system and rotating coordinate system, and the circulation mathematical model of rectifier parallel system are established. Based on the mathematical model, a double-closed loop control system of rectifier is established. In order to solve the problem that three-phase PWM rectifier will cause AC side current distortion in unbalanced state of power network, a parallel control method is proposed in this paper. Two rectifiers are used to control the rectifier under unbalanced conditions, and a group of rectifiers produce positive sequence current. The other group generates negative sequence current, and the capacity expansion and harmonic suppression of rectifier are realized by parallel control. In order to eliminate the influence of the circulation, a coordinated control strategy is proposed to suppress the negative sequence and zero sequence circulation between the rectifiers. The load power distribution is realized by controlling the positive sequence current component. The simulation model of three-phase PWM rectifier under unbalanced power network and parallel control is built with Matlab software, and the correctness of each control strategy in this paper is verified. Finally, combined with the theoretical derivation and simulation, the hardware parameters and models that meet the requirements of the experiment are determined, and the driving circuits and conditioning circuits are designed. The experimental platform is constructed with TMS320F2812DSP as the core. Design the software flow and compile the software program in C language in CCS compile software. Through the simulation analysis and experimental debugging, the PWM rectifier grid-side current and DC side voltage control under the condition of unbalanced power grid is well realized.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM461

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