与电网电压同步的单位正余弦波发生电路研究

his paper first introduces the basic principle of phase lock loop, Then a structure diagram of sine wave generation circuit Synchronous with grid is constructed based on this principles. Each part of the circuit is designed，ultimately the sine wave Synchronous with A-phase voltage is produced. The author introduces a new phase-shift circuit mainly to overcome the shortcomings of the signal attenuation and serious distortion of the signal after the phase-shift of general RC phase shift circuit. The cosine wave is produced by advanced phase shift 90 of the generated sine wave. Ultimately by conditioning the generated sine and cosine waves, unit sine and cosine waves Synchronous with A-phase voltage can be obtained. This can be used directly in the ip-iq harmonic detection and other hardware and software implementations of harmonic detection methods, besides this, it can improve the real-time of harmonic detection.