Design Of Harmonics Measurement System In Power System Based On FPGA

The harmonic has become an menace to electrical power system,especially with the increase of our country's electrical network installed capacity and the electric and electrical components' application.The measurement of harmonic is the foundation of research other harmonic question.The domestic and foreign experts has done many researches in the harmonic measurement theory.The FFT harmonic measurement theory has been mainly used in practical application because of the good effect,the shorter calculate time to DFT,and the succeed application.The domestic harmonic measurement is mainly based on the DSP.This design can be enhanced in instrument function consummate and the cost's reduce.Field Programmable Gate Array is a new type of programmable device at high speed development this year.The superiority in the digital signal processing,caused the enhancement of the scale and the integration in electronic design.And provides an kind of new design concept in the harmonic measurement design.This article mainly probe into the digital harmonic measuring system with high accuracy high real-time character in measuring theory and realized approach.This article deeply studies the use of FFT theory in harmonic measurement,analyzes the frequency spectrum divulging and the stockade effect's question in application,this article analyzes three solution methods,and uses the phase locking frequency synchronization technology to solutes frequency spectrum divulging and stockade effect question.This article researches in the harmonic measurement's hardware and software design,which based on the FPGA.The hardware design mainly includes:CT/PT sensor unit,phase locking synchronous sampling control circuit,data acquisition unit, CPU control system,FFT process unit based on FPGA,keyboard and LCD circuit, FIFO memory unit,and communication unit.The data acquisition unit uses the dynamic floating gathering technology,has satisfied the system gathering speed and the accuracy need.The software design uses base-2 Decimation in Time(DIT) algorithm.The software design includes:butterfly-shaped arithmetical unit,the data interception unit,the address calculate unit,pingpong RAM unit.and the twiddle factor ROM memory unit.The entire FFT unit design uses the pipelining production structure,and the butterfly arithmetical unit uses the compound structure to improve the utilization of FFT unit.The whole design uses the Altera Corporation's Cyclone series FPGA chip as the core design.Uses the Quartusâ…¡which is provided by Altera Corporation as the software platform.Uses the VHDL language realized the whole system's design.The analysis result can be real time displayed,or transmit to the superior machine to benifit for the entire electrical network system's.is advantageous for the entire electrical network system's direction.The whole system fulfills the national overtone examination standard,has certain theory significance and the use value.