The design of Reference Sinusoidal Signal Generator Circuit for Photovoltaic Grid Based on CPLD

The Frequency and Phase that equal to Grid voltage of Reference Sinusoidal Signal is important to the network equipment and Current waveform quality. The Design of Reference Sinusoidal Signal Generator Circuit for Photovoltaic Grid Based on CPLD with Frequency tracking and Phase tracking is given in the paper. The circuit includes Sampling circuit, Signal conversion circuit, Frequency tracking and Phase tracking circuit, D/A Conversion circuit. The Waveform accuracy is discussed and the Experimental results are given in the paper. The CPLD used in the system reduces the size of the digital circuit, reduces the equipment size, and makes Debugging easy. The results show that the circuit can generate Reference Sinusoidal Signal that equal to Grid Voltage with frequency and phase, and the signal has small total harmonic distortion. The circuit is Simple and practical, and has Low prices.