The Research On Harmonic Detecting Methods In Power System Based On FPGA

With the development of technology, power electric device such as Frequency Converter become more and more powerful and its numbers increased quickly. Due to the widespread use of nonlinear device nowadays, harmonic problem becomes more and more serious, and take more damage to other electric device. The damage include increasing of power consume, shortage of device life, more serious damage could create power accent and affect the product, power system harmonic has already become the public hazard of power system. Besides conventional solutions such as passive filters and changed system configurations to restrain harmonic problems, the use of active power filters (APF) to eliminate harmonic currents injected by nonlinear loads has attracted much attention. The premise of realizing APF is to detect the harmonic currents quickly and accurately. Harmonic measurement is one important branch of harmonic research, and is the foundation to solve other harmonic problems, so mere is important theoretical and practical significance in research of harmonic measurement. Many scholars aim to design a harmonic detecting method with good real time, high precision and wide applicability.This thesis mainly discusses the digital harmonic measuring system with high accuracy and high real-time on measuring theory and realized approach. The thesis explains the relevant concepts of power system harmonic and the principle of harmonic producing, the thesis analyses the characters of harmonic and studies all kinds of harmonic detecting methods in the world, In measurement theory, the thesis adopts FFT theory to calculate harmonic content, studies the process of Radix-2 FFT for harmonic measurement. We discuss the promise and problems of reprogrammable systems, and it development on both technology and application, and introduce VHDL. At last, at the hardware base of XC2S200, at the software base of ISE, by using VHDL, it realizes the FFT system of 512-point that is 16-Bit number, and finishes the work of stimulation and synthesis. The results of simulation show calculate-result reaches equivalent precision, the operational speed of FFT can satisfies the request of commonly realtime signal processing.