三相背靠背变流器的研究

发布时间：2018-11-24 17:06

【摘要】：能源紧缺和工业负载多元化,促使电能变换技术向着高效节能的方向发展。变流器作为电能变换任务的主要承担者,在工业生产中发挥着不可替代的作用。然而从目前变流器的发展情况来看,传统交-直-交变流器采用不可控整流或相控整流方式,使得变流器产生大量谐波电流,造成谐波污染。更重要的是其能量只能单向流动,回馈的电能不能再次输送给电网造成能源浪费。因此如何解决这些问题成为电力电子电能变换领域一个热点问题。由于背靠背变流器采用PWM可控整流方式具有四象限运行、网侧电流连续正弦化、直流电压可控和单位功率因数运行等优势,成为解决这些问题最有效的方法。然而从目前背靠背变流器工作性能来看,依旧存在高频谐波电流和负载功率变化时直流电压动态响应不足等问题,这就限制了背靠背变流器的工作性能以及效率的提高,所以对于上述问题的解决对变流器的发展及应用有着深远的意义。本文以三相电压型背靠背变流器作为对象进行了全面研究,在原理分析、数学建模等基础上对变流器的控制系统进行设计,并且通过仿真和样机实验对所述方案的进行了验证。其主要研究内容如下:(1)分析变流器发展现状,总结变流器控制方法和应用领域。对变流器控制中所采用的不同算法进行分析,发现目前背靠背变流器存在系统响应速度慢,负载变化时直流母线电压波动大及对谐波电流控制不足等问题。(2)背靠背变流器工作原理分析及建模。通过对坐标变换方法的研究,分别在三相静止坐标系、两相静止坐标系及两相旋转坐标系上建立变流器的数学模型,并且以三相异步电机为例对变流器负载的数学模型进行分析。(3)以数学模型为基础,对变流器控制方法进行研究。分别对PWM整流和逆变几种常用控制算法及控制参数的选取进行分析,并且对不同算法特点进行比较。在此基础上,针对减小谐波电流、提高负载变化时响应速度和电能利用率这一关键问题将电流无差拍控制和有功功率反馈补偿应用在变流器控制中。除此之外对基于双二阶广义积分的软件锁相环技术和SVPWM技术进行了阐述。最后通过Matlab进行仿真及结果分析,验证控制方法的可行性。(4)采用DSP作为主控制芯片,配合IGBT模块构成的功率变换电路、驱动电路、信号调理电路等对变流器进行了软硬件设计。软件设计采用基于模型设计的方法进行代码生成,使得程序编写工作量大幅减小。最后通过实验及结果分析验证上述方案有效可行。通过对仿真及实验结果的分析和比较,证明本系统在满足背靠背变流器控制要求的同时,将电流无差拍控制、有功功率反馈补偿的方法应用于变流器控制中,有效的减小了变流器的谐波污染,并且在负载变化时提高了直流侧电压稳定性和系统响应速度,使得变流器电能利用率提升,工作性能更加优异。
[Abstract]:The shortage of energy and the diversification of industrial load promote the development of energy conversion technology towards high efficiency and energy saving. As the main carrier of power conversion task, converter plays an irreplaceable role in industrial production. However, according to the development of the converter, the traditional AC-DC-AC converter adopts uncontrollable rectifier or phase-controlled rectifier, which makes the converter produce a large amount of harmonic current and cause harmonic pollution. What is more important is that the energy flow can only be unidirectional, and the feedback energy can not be transmitted to the power grid again resulting in energy waste. Therefore, how to solve these problems has become a hot issue in the field of power electronic power conversion. Because the PWM controlled rectifier has the advantages of four-quadrant operation, continuous sinusoidal current on the grid side, controllable DC voltage and unit power factor operation, it is the most effective method to solve these problems. However, from the point of view of the current performance of back-to-back converter, there are still some problems such as insufficient dynamic response of DC voltage when high frequency harmonic current and load power change, which limits the performance and efficiency of back-to-back converter. Therefore, the solution to the above problems is of great significance to the development and application of the converter. In this paper, the three-phase voltage-source back-to-back converter is studied in detail. The control system of the converter is designed on the basis of principle analysis and mathematical modeling, and the scheme is verified by simulation and prototype experiments. The main research contents are as follows: (1) the development of converter is analyzed, and the control methods and application fields of converter are summarized. By analyzing the different algorithms used in converter control, it is found that the system response speed is slow. The DC bus voltage fluctuates greatly and the harmonic current is not controlled enough when the load changes. (2) the working principle analysis and modeling of back-to-back converter. Through the research of coordinate transformation method, the mathematical models of converter are established in three-phase static coordinate system, two-phase static coordinate system and two-phase rotating coordinate system, respectively. And take the three-phase asynchronous motor as an example to analyze the mathematical model of the converter load. (3) based on the mathematical model, the control method of the converter is studied. Several common control algorithms and control parameters of PWM rectifier and inverter are analyzed, and the characteristics of different algorithms are compared. On this basis, the current deadbeat control and active power feedback compensation are applied to the converter control in order to reduce the harmonic current, improve the response speed and the power utilization ratio when the load changes. In addition, the software phase locked loop and SVPWM technology based on two-order generalized integral are discussed. Finally, the feasibility of the control method is verified by Matlab simulation and result analysis. (4) DSP is used as the main control chip, and the power conversion circuit and driving circuit are combined with the IGBT module. The signal conditioning circuit and so on have carried on the hardware and software design to the converter. The software design adopts the method of model design to generate code, which greatly reduces the workload of programming. Finally, the experiment and result analysis show that the scheme is effective and feasible. Through the analysis and comparison of the simulation and experimental results, it is proved that this system not only meets the control requirements of back-to-back converter, but also applies the method of current no-beat control and active power feedback compensation to the control of converter. The harmonic pollution of the converter is reduced effectively, and the DC voltage stability and the system response speed are improved when the load changes. The power utilization ratio of the converter is improved and the performance of the converter is improved.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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