A Novel 5-level front-end bidirectional diode clamped AC-DC-AC converter

Abstract

This project proposes novel multilevel AC/DC/AC converters with reduced number of semiconductor devices to achieve light weight, efficiency and better input current quality. The proposed three-phase front-end bidirectional five-level (5L) rectifier and rear-end 5L-inverter are constructed based on multiple-pole multilevel diode-clamped approach (M²DCC), which consist a total number of 24 diode components clamped. Based on M²DCC concept, the number of switching devices can be further reduced to construct a new unidirectional front-end rectifier (M²SCR). Comparative studies are conducted to analyze the performances of the two proposed front-end rectifiers with supportive mathematical derivations. In this project a single-stage converter was proposed for integrating Wind system with Grid by reducing the number of switches.  Due to incident wind speed, maximum output power of wind turbine is obtained in different speed of the turbine. The generator speed must be adjusted according to instantaneous wind speed to obtain incident maximum power. Tip speed ratio (TSR) technique is used for MPPT. This MPPT method will generate the reference speed for speed controller of PMSG. The comparative analysis has been done for steady and transient state wind speeds.