Digital-analog hybrid controlled LCL type grid connected inverter

Abstract

With the continuous development of renewable energy power generation system, the research on grid-connected inverters becomes very important. This project presents a new type of control theory for LCL type grid tied inverters-the hybrid digital-analog control system. It contains digital feedback control which achieved by Hardware-in-the-loop(HIL) and analog feedforward control which achieved by OPAL-RT. The hybrid digital-analog system combines the high-speed processing performance of digital control and the real-time simulation of analog control. It also avoids the delay problem during the experiment process, and significantly improves the stability of the system and capability of suppressing harmonics.