Abstract—In low-power renewable systems, a single-phase grid-connected converter is usually adopted. This project deals with a five-level converter that follows this trend. The proposed converter architecture is based on a full-bridge with two additional power switches and two diodes connected to the midpoint of the dc link. Since the two added levels are obtained by the discharge of the two capacitors of the dc link, the balancing of the midpoint voltage is obtained with a specific Pulse Width Modulation (PWM) strategy. The hardware design is implemented by PIC16F877A controller circuit.This project proposes a five-level converter based on a full-bridge topology with two added power switches and two diodes connected to the midpoint of the dc link. In order to balance the midpoint voltage, a specific PWM strategy was developed. This solution is designed for renewable energy systems, where unity power factor operations are generally required. nevertheless, a variation of the proposed topology which allows four-quadrant operations. Multilevel converter allow to reduces the harmonic content of the converter output voltage, allowing the use of smaller and cheaper output filters. Moreover, these converters are usually characterized by a strong reduction of the switching voltages across the power switches, allowing the reduction of switching power losses.

Index Terms—Terms-clamp circuit, MOSFET circuit, DC-converter, PIC microcontroller

Cite: R Bhavani, U Dhanalakshmi and C Kamal, "A MULTI-LEVEL SINGLE-PHASE GRID CONNECTED CONVERTER FOR RENEWABLE DISTERBUTED SYSTEM," International Journal of Electrical and Electronic Engineering & Telecommunications, Vol. 1, No. 1, pp. 311-318, March 2015.