The Design Of The Portable Single-phase Voltage Event Recorder

With the development of social economy and the improvement of science andtechnology, increasingly improve the requirement of the power quality, at the same time,more and more high power load and switching power supply is used by people, the gridis injected more interference, which threatened the sensitive load and so on. So it is verymeaningful to design a new type of real-time power quality monitoring system.This paper presents a design scheme of power quality analyzer on the basis ofFPGA. It not only can complete record of events in all kinds of voltage and frequencymeasurements, but also can analyze harmonic in the circuit by useing the method of fastFourier transform. The system design is divided into two parts: analog circuit anddigital circuit. The design of the analog circuit part including: signal acquisition circuit,Gain circuit, analog-to-digital conversion circuit, Comparison of shaping circuit and soon,which mainly completes signal extraction, amplification and analog-to-digitalconversion. In the digital part, Nios II processor within FPGA is used as the controlcenter, and frequency measurement circuit, serial-to-parallel converting circuit, ping-pang memory, clock divider, and FFT module are designed. FFT module is generatedby the FFT IP core supplied by Alter, and the other modules are generated byVerilog_HDL language. SOPC Biulder instrument is used to add all the functionmodules into Nios II system. At last, the simulation shows that the digital logic design isreasonable.This article is designed for portable single-phase voltage event recorder whichtakes full advantage of FPGA at processing high speed signal, and chooses chips withhighly integrated, high-efficiency signal processing, good signal consistency and lowpower consumption, not only has a good practical and economic value, but also has areference effect on the design and research for power quality analysis recordinginstruments.