Voltage Source Converter Training System

Abstract

Voltage Source Convertors are used to convert the power from one source to another e.g. from AC-DC or DC-AC. We need to convert the power for transmission for this purpose we voltage convertors. There are different types of convertors are available. In 2013 an uncontrolled VSC is developed by Ralph Feldman and Matteo Tomasin using ordinary semi-conductor diodes. Then in 2018 Tao Jing Alexander S. Maklakov design a PWM controlled VSC and explained the applications of energy storage devices. These convertors was only allow power to flow in only one direction after and in 2019 a bidirectional convertor are developed by Euzeli C. dos Santos. All these convertors have problem in current controlling. Now this VSC will perform the stepwise conversion of power. In these convertors MOSFETs or IGBTs used as switches due to their high reliability in conversion of power and PWM technique is used for the controlling in PWM control technique the output signal come from the convertor compare with a reference signal and find an error signal then this error. This error signal comes to the PWM control unit and the PWM pulses generates at the output of PWM control unit. These PWM pulses are given to the gates of IGBTs and the final controlled output is formed at the output of VSC trainer. At the output the power is monitored continuously.These convertors are operates in standalone mode and in grid tied mode. In standalone mode the power flow only in one direction from source to load. In Grid tied we connect grid instead of load and the power flow in both directions. For flow current from source to grid the inverter current must be in phase and for grid to source 180 degree shift given between grid voltage and inverter current. In order to run the system bi-directionally, there must be a control technique for the flow to current. Current within the system allows to operate the trainer either as a rectifier or an invertor. For controlling the current, the voltage oriented current control performs its major role by setting the current orientation with respect to line voltage current.