基于DSP的双向功率计量与谐波检测系统研究设计

发布时间：2018-07-02 14:52

本文选题：双向功率 + 非正弦　；参考：《广西大学》2017年硕士论文

【摘要】：随着含有分布式电源的家庭微电网接入电力系统,自发自用/余电上网的工作模式使得配电网的潮流分布呈现出双向性,由此带来了双向电能计量问题。此外,家庭微网中大量的电力电子设备已经成为居民用电的主体,如微波炉、计算机、充电汽车、储能电池整流装置等,由此造成的非正弦工况需要功率计量装置具有更公平合理的计量方案、算法,而且能够同时监控用户的电能质量以制定不同的收费策略。分布式电源的双向电能计量以有功计量为核心,本文以传统的计量关口作为计量点,利用基波功率方向同四象限功率定义相结合判定双向功率的方向。传统的功率理论和计量方法是建立在正弦情况下,在非正弦情况下的谐波会造成电能表计量不准确、不公平。本文对比分析了非正弦工况下频域、时域、时频结合的三种功率理论对计量影响,进行了 MATLAB仿真分析验证。结合电流物理分量(CPC)功率理论中背景谐波和反射谐波的定义,本文提出一种综合计量方案,即微电网正向受电时分别计量基波有功、背景谐波有功、反射谐波有功、绝对值无功,微电网反向馈电时分别计量基波有功、谐波有功。本文采用快速傅里叶(FFT)方法进行谐波检测和功率计算,分析了其产生频谱泄漏和栅栏效应的原因、以及常用窗函数和检测精度问题。针对非同步采样,本文基于时域汉宁窗互乘的方法构建了三项余弦组合窗,分析互乘汉宁窗的时频特性,并同汉宁窗、四项莱夫文森特窗进行仿真对比分析。并采用双谱线插值法结合互乘汉宁窗改进FFT算法,对改进的算法进行了谐波检测和功率计量仿真,结果表明改进算法可以有效抑制频谱泄漏,对功率计量和谐波检测有较高的精度。在互乘汉宁窗双谱线插值改进FFT算法的基础上,本文基于TMS320F28335 DSP和AD7606硬件结构,研究开发一款功率计量和谐波检测一体化的装置,完成了系统的硬件、软件设计和外设电路制作调试。详细介绍了硬件芯片资源分配、核心电路、高频信号采集电路、通信电路。根据模块化设计流程,设计和调试系统主程序、电参量计算程序和串口通信程序,同时利用DMA上传采样数据至DSP以保证实时性。采用cMT-SVR上位机设计了人机交互界面,方便用户实时查看电量信息。最后结合实验室现有设备进行实验,结果表明系统可以实现采集检测功能以及谐波分析和功率计算功能。
[Abstract]:As the home microgrid with distributed power supply is connected to the power system, the spontaneous self-use / surplus power network mode makes the distribution of power flow of the distribution network bidirectional, which brings about the bidirectional power measurement problem. In addition, a large number of power electronic devices in the household microgrid have become the main power users, such as microwave ovens, computers, rechargeable cars, energy storage battery rectifiers, etc. The resulting non-sinusoidal conditions require that the power metering device has a more fair and reasonable metering scheme, an algorithm, and the ability to monitor the power quality of the user at the same time in order to formulate different charging strategies. Active power measurement is the core of the bidirectional power measurement of distributed power generation. In this paper, the traditional metering gate is taken as the measuring point, and the direction of bidirectional power is determined by combining the fundamental power direction with the four-quadrant power definition. The traditional power theory and metering methods are based on sinusoidal conditions. Harmonics in non-sinusoidal situations will cause inaccurate and unfair measurement of watt-hour meters. In this paper, the effects of frequency domain and time-frequency combined power theory on measurement are compared and verified by MATLAB simulation. Combined with the definition of background harmonics and reflected harmonics in current physical component (CPC) power theory, a comprehensive measurement scheme is proposed in this paper, that is, the fundamental active power, background harmonic active power and reflected harmonic active power are measured respectively when the micro-grid is positively charged. Absolute reactive power, microgrid reverse feed measurement of fundamental active power, harmonic active power. In this paper, the fast Fourier transform (FFT) method is used for harmonic detection and power calculation. The causes of spectrum leakage and fence effect, as well as the common window function and detection accuracy are analyzed. Aiming at asynchronous sampling, this paper constructs three cosine combination windows based on the method of time domain Hanning window multiplication, analyzes the time-frequency characteristics of the cross-multiplication Hanning window, and makes a simulation comparison with the Hanning window and four Lefe Vincent windows. The harmonic detection and power measurement simulation of the improved FFT algorithm are carried out by using the double spectral line interpolation method combined with the improved FFT algorithm. The results show that the improved algorithm can effectively suppress the spectrum leakage. It has high accuracy for power measurement and harmonic detection. On the basis of the improved FFT algorithm based on the double spectral line interpolation of the Hanning window, based on the TMS320F28335 DSP and AD7606 hardware structure, this paper studies and develops an integrated device of power measurement and harmonic detection, and completes the hardware of the system. Software design and peripheral circuit debugging. The hardware chip resource allocation, core circuit, high frequency signal acquisition circuit and communication circuit are introduced in detail. According to the modularization design flow, the main program, electric parameter calculation program and serial port communication program of the system are designed and debugged. At the same time, DMA is used to upload the sampling data to DSP to ensure real-time performance. The man-machine interface is designed by using cMT-SVR PC, which is convenient for users to view electricity information in real time. Finally, the experimental results show that the system can realize the functions of collection and detection, harmonic analysis and power calculation.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM935

【参考文献】