关键词: 脉冲发电机, 宽频率, 锁相环, 滤波器, 同步坐标系

Abstract: In order to solve the problem that the traditional phase-locked loop cannot perform correct phase-locking under the condition of the fundamental frequency is variable, a tracking three-phase software phase-locked loop based on the synchronous reference coordinate system is proposed. The three-phase voltage signal (V_a, V_b, V_c) is transformed by the synchronous coordinate to obtain the two-phase stationary coordinate signal (V_α, V_β), and then the signal (V_d, V_q) is obtained after the rotating coordinate. Then the Vq signal is low-pass filtered and through dynamic signal delay. The delay time is obtained from the output frequency signal. The signals difference of before and after the delay are adjusted by PID and output as the angular frequency. After the angular frequency is integrated, the stable fundamental positive sequence phase is obtained. In order to verify the algorithm, a simulation model is established based on matlab. The simulation results showed that the phase shift time of the PLL was less than 0.2ms in the case of the linear change of the fundamental wave frequency of the power supply, and In the case of non-linear changes in the fundamental frequency of the pulse generator voltage, it takes one cycle to obtain accurate phase lock. Its application in active power filters effectively suppresses the output harmonics of pulse generators.

Key words: Pulse generator, Wide frequency, Phase locked loop, Filter, Synchronous coordinate system