Endüstriyel Amaçlı Yarım H-Köprü Modüllü Üç Fazlı Çok Seviyeli Evirici Yapısı

Abstract

In this paper, a new three phase multi-level inverter topology has been developed for industrial purposes. Half H-bridge level modules exist in the inverter structure. In order to change the number of levels in the output voltage, the number of level modules is changed. With the increase in the number of levels, the output voltage approaches the sinusoidal form and the total harmonic distortion (THD) values in the voltage and current decrease. The proposed inverter structure is very flexible and switching signals can be found by the generated equations. The switching strategy is not complicated. Proposed inverter was simulated for different levels and voltage and current waveforms were obtained. THD values of these waveforms were calculated. Compared with the classical Space Vector Modulation (SVM) and Pulse Width Modulation (PWM) inverters, it is seen that both current and voltage harmonics are low together. However, current harmonics are low in conventional SVM and PWM inverters, but voltage harmonics are high. The improved inverter also closes this gap by reducing the voltage harmonics. In addition, another disadvantage of conventional SVM and PWM inverters is the high voltage stresses (dv/dt) on the switching elements. Since the proposed inverter has levels on the output voltage, the dv/dt stresses on the switches are also low. Additionally, the developed inverter structure has the switch number advantage compared to its counterparts.