Abstrakt

Modulation Strategies For Three Phase Inverters Supplying Unbalanced Three Phase Loads

J. Joe Brislin, J. Chelladurai, B. Vinod, M. Sundaram

The main focus of the paper is to study the different modulation techniques used for three phase VSI supplying single phase loads that require neutral connection. Two types of topology of three phase inverter, namely three-leg and four-leg inverter are considered. PWM techniques used for both the topologies are described. The three dimensional space vector modulation used for four-leg inverter is discussed in a detailed manner. Though the four-leg inverters are less commonly used, it is the only possible solution for providing neutral connection to supply single phase loads from three phase inverter. The four-leg VSI presents advantages in a wide manner covering less dc link capacitance, high dc link voltage utilization and low distortion at output. The performance of various modulation strategies has been analyzed and verified using simulation in MATLAB environment.