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

摘要： 针对在基波频率变化情况下传统锁相环无法进行正确锁相的问题，提出了基于同步参考坐标系的追踪型三相软件锁相环。三相电压信号(V_a、V_b、V_c)经同步坐标变换后，得到两相静止坐标(V_α、V_β)信号，再经过旋转坐标变化后获得(V_d、V_q)信号；V_q信号经过低通滤波后，进行动态信号延迟，其延迟的时间由输出的频率信号获得；把延迟前后的信号做差，经过PID调节后输出为角频率，对角频率积分后获得稳定基波正序相位。为了验证该算法，基于matlab建立了仿真模型。仿真结果表明，该锁相环在电源基波频率线性变化情况下其相移时间小于0.2ms，在脉冲发电机电压基波频率非线性变化情况下需要经过一个周波也能获得精准地锁相，其运用于有源电力滤波器有效地抑制了脉冲发电机的输出谐波。

关键词: 脉冲发电机, 宽频率, 锁相环, 滤波器, 同步坐标系