Research Of High Precision Power Quality Analysis System Based On ARM+FPGA

With the development of science technology and social economy,the demand for power quality is increasing.Based on the measurement and analysis voltage of the power quality parameters such as current,frequency,three-phase unbalance and harmonic,the power quality can be monitored and evaluation effectively.The existing power quality analysis system has the problems of low measurement accuracy,poor real-time performance and lack of system networking,which cannot fully meet the market demand.Therefore,it is of great significance and value to develop power quality analysis system with high performance.The power quality analysis system with high accuracy was studied.According to the requirement analysis and design objectives,the overall scheme of the system was designed,which was composed of data acquisition module,data processing module and human-computer interaction module.The core of data acquisition module was high precision AD7609.A good signal conditioning circuit was designed by resistor voltage divider,voltage following,single-end differential and RC filter circuit.A low jitter clock circuit was designed based on Si54 x,a high precision reference circuit was designed by ADR421 B,and a double SRAM buffer circuit was designed by IS61WV25616.Parallel synchronous sampling and double SRAM table tennis operation were adopted to realize high-speed data acquisition and caching,which provided basis for high precision measurement of the system.Data processing module was based on dual core architecture of ARM + FPGA.Through the research of power quality analysis algorithm,the phase difference frequency estimation method was used to correct the frequency amplitude,and a high precision power quality analysis algorithm based on all phase FFT method was proposed.The logic circuit of all-phase FFT method was built in the FPGA.Combining with the FPU of ARM,the highprecision measurement of power quality parameters was realized,and the processing speed and accuracy of the system were improved.The human-computer interaction module is composed of Ethernet communication and liquid crystal display.Based on Ethernet PHY chip LAN8720 and LWIP protocol,the design of Ethernet communication interface was realized.Through the research of HTTP protocol and FTP protocol,the WEB dynamic display server and FTP file transfer server were built,and the remote management and data sharing of the system were realized.Manmachine interaction was achieved by the use of LCD touch display device.The experimental results showed that when the standard signal was used as the measurement object,the measurement accuracy of electrical parameters reached the national A-level standard,and the system analysis speed reached the ms-level,which verified the high accuracy and real-time performance of the system.The system can achieve high-precision measurement and data analysis of electrical parameters,and has good real-time performance,low cost and comprehensive functions,which fully meets the requirements of power quality analysis technology and has good application prospect.