基于FPGA硬件实现的谐波检测方法  

Realization of Harmonic Measurement Based on FPGA Hardware

作　　者：范必双[1] 王英健[1] 王玉凤[1] 

机构地区：[1]长沙理工大学电气与信息工程学院,湖南长沙410076

出　　处：《计算机仿真》2008年第4期235-240,共6页Computer Simulation

摘　　要：针对现有系统对谐波检测实时性差和精度低的问题,介绍一种基于傅立叶变换和FPGA硬件实现的谐波检测方法。分析了谐波检测中影响测量精度的关键因素,采用数字锁相环来同步被测信号,以减小由非同步采样所产生的误差。基-4FFT处理器的硬件设计采用全并行的乘法运算单元结构和并行的存储分配方法,最大限度地提高谐波检测的速度。数字锁相环和基-4FFT算法用VHDL语言设计实现,并用MAX+plusⅡ软件进行仿真,仿真结果表明,所设计的数字锁相环可以很好地跟踪被测信号,在180ms时,误差仅为0.01Hz,很好地消除了非同步采样所引起的测量误差;采用所设计的基-4FFT运算器对给定的谐波数据进行运算,得到的谐波幅值和相位误差小于0.05%,运算时间仅为8μs。A technique for realizing harmonic measurement based on Fourier Transform Algorithm and FPGA is presented to solve the problem of low speed and low accuracy of harmonic measurement system in existence. The key factors affecting the speed and accuracy of harmonic measurement are discussed, and the Digital Phase Locked Logic （DPLL） is used to synchronize the tested signal to minish the error caused by asynchronous sampling. The multiplication cells and storage units of the radix -4 FFT are highly parallelized to farthest improve the speed of harmonic measurement. The circuits of DPLL and radix -4 FFT are designed with VHDL language and simulated with MAX ＋ plus Ⅱ software. The simulation result shows that the designed DPLL hardware is good for tracking the tested signal with an error of only 0. 01Hz at 180ms. The simulation result also shows that the designed radix -4 FFT hardware is of high speed and accuracy with an error less than 0. 05%, taking only 8 μs.

关 键 词：谐波检测 现场可编程逻辑器件 数字锁相环 快速傅立叶变换 

分 类 号：TM93[电气工程—电力电子与电力传动]