The structure of photovoltaic grid connected inverters mainly consists of a front-end DC/DC converter and a back-end DC/AC inverter. The basic principle is to convert low-voltage direct current into high-voltage direct current through high-frequency conversion technology, and then obtain 220V alternating current through a power frequency inverter circuit. This structure has the advantages of simple circuit, low no-load loss of the inverter power supply, high output power, high inverter efficiency, good stability, and low distortion.

The control of the DC/DC module of the inverter main circuit uses the SG3525 chip. SG3525 is a dual output SPWM pulse width modulation chip that generates a PWM waveform with variable duty cycle to drive the gate of the thyristor to control its on/off, thereby achieving the goal of controlling the output waveform.