Modified low switching frequency space vector modulators for high power multi-module converters

Force-commutated PWM controlled multi-converter systems have been proposed for high power applications, particularly reactive power compensation and FACTS devices. Advantages of the space vector modulation make this PWM technique the preferred technique especially for high power applications. This paper presents new low switching frequency SVM strategies that lead to symmetrical and high quality output voltages fulfilling the high power application standards. Pattern generation options are analyzed and system waveforms are presented for different switching frequencies and number of modules. Results are validated by simulation and confirmed by experiments on a 5 kVA prototype unit.