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Study on SPLL of Grid-connected PV generation system

If there is a tiny frequency difference between Grid frequency and grid frequency, the grid electricity transmission can be influenced. To solve this problem, the grid phase locked loop technique principle was introduced. At the same time, the grid frequency tracking locking was realized by FPGA. Through the locking the frequency of DSP, SPWM wave was produced. Finally, the voltage from LC filtering was connected with grid. The 2 KVA prototype test verifies the feasibility of this method. And thus, the grid inverter can transmit the electricity stable and reliable.