三电平有源滤波器建模及控制策略

发布时间：2019-04-19 23:14

【摘要】：保证较高的供电质量、提高电力生产与运行的效率、提高电力系统运行可靠性,是电力改革的目标。谐波污染严重是我国电能损耗高的重要原因之一,并且现代电网中存在大量敏感性负载,终端用户对电能质量要求越来越高。谐波抑制是提高电能质量的有效措施,有源电力滤波器(Active Power Filter,APF)是其重要设备,因此对有源电力滤波器的研究具有实际意义。本文针对有源电力滤波器输出谐波电流的特性及运行要求,首先确定系统总体设计方案,选定带LC滤波器的二极管箝位型(Neutral Point Clamped,NPC)三电平拓扑结构,并简要地分析其工作原理。重点研究有源电力滤波器控制器参数的精确设计问题,在传统直流侧电压控制模型基础上,建立其在dq旋转坐标系下电压控制小信号模型,进而提出一种基于小信号模型的PI参数整定方法。采用零极点配置将含有右半平面零点的小信号模型转化为普通的二阶滞后系统,根据劳斯判据和两步整定法详细讨论了PI参数的选取原则,重点分析不同PI参数对系统性能的影响。仿真和样机实验结果都表明,该方法的可行性。然后,在理论研究的基础上设计了有源电力滤波器的硬件电路及软件系统。硬件主要包括主电路电感与电容的参数计算、控制系统隔离电源及辅助电源设计、ADC采样及信号调理电路、IGBT驱动接口电路、保护电路、接触器控制电路;软件部分主要包括各中断服务子程序、谐波提取滤波程序、单同步坐标系软件锁相环程序、位置式数字PID程序等。最后,在上述基础上搭建了6kVA(按照25%电流畸变率计算)三电平有源电力滤波器实验样机,按照设计方案对样机进行调试,在调试过程中不断对系统进行优化升级,并使用示波器、电能质量分析仪测得相关实验波形。对测得的电网电压波形、直流侧电容电压波形、电网电流及有源电力滤波器输出电流波形等实验结果分析,表明了有源电力滤波器采用的控制策略和总体设计的可行性,在保证系统补偿性能的同时直流电压具有较小的超调,能够有效降低电网电流畸变率,达到了设计的各项性能指标。
[Abstract]:It is the goal of electric power reform to ensure high power supply quality, to improve the efficiency of power production and operation, and to improve the reliability of power system operation. The serious harmonic pollution is one of the important reasons for the high power loss in our country, and there are a lot of sensitive loads in the modern power grid, and the end-users require more and more high power quality. Harmonic suppression is an effective measure to improve power quality, and active power filter (Active Power Filter,APF) is an important equipment, so the research on active power filter is of practical significance. According to the characteristics and operating requirements of active power filter (APF) output harmonic current, the overall design scheme of the system is determined firstly, and the diode clamped (Neutral Point Clamped,NPC (3-level topology) with LC filter is selected. And its working principle is briefly analyzed. The precise design of the controller parameters of active power filter (APF) is studied. Based on the traditional DC side voltage control model, the small signal model of voltage control in dq rotating coordinate system is established. Furthermore, a small-signal model-based PI parameter tuning method is proposed. The zero-pole assignment is used to transform the small signal model with right half-plane zeros into the ordinary second-order delay system. The selection principle of PI parameters is discussed in detail according to the Rous criterion and the two-step adjustment method. The effect of different PI parameters on the performance of the system is emphatically analyzed. The results of simulation and prototype experiments show that the method is feasible. Then, based on the theoretical research, the hardware circuit and software system of active power filter are designed. The hardware includes main circuit inductance and capacitance parameter calculation, control system isolation power supply and auxiliary power supply design, ADC sampling and signal conditioning circuit, IGBT drive interface circuit, protection circuit, contactor control circuit; The software includes interrupt service subroutine, harmonic extraction filter program, single synchronous coordinate system software phase locked loop program, position digital PID program and so on. Finally, an experimental prototype of three-level active power filter (6kVA) is built on the basis of the above mentioned, and the prototype is debugged according to the design scheme, and the system is continuously optimized and upgraded during the debugging process. And using oscilloscope, power quality analyzer to measure the relevant experimental waveforms. The experimental results such as grid voltage waveform, DC side capacitance voltage waveform, grid current and output current waveform of active power filter (APF) are analyzed, and the feasibility of the control strategy and overall design of APF is shown. While ensuring the compensation performance of the system, the DC voltage has a small overshoot, which can effectively reduce the current distortion rate of the power network and achieve the performance indexes of the design.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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