Application of delta modulation strategy to series connected inverters

Abstract

Modulation strategies play a vital role in the control of inverters. Even though variety of modulation strategies are available only a handful of them are both, simple to be easily implemented by programmable computers and capable to provide satisfactory performance. A novel concept, which is comparatively simple and effective, has been presented here to extend most of the two level inverter modulation strategies to control any levels of series connected inverters. This is achieved by utilizing the concept of de-multiplexing based on threshold detection of the modulating signal. In order to demonstrate the simplicity and effectiveness of the proposed method, delta modulation strategy has been used to generate switching signals. The switching signals are then used to control a five-level and seven-level series connected inverter by employing the proposed method. Performance of these inverters has been analyzed through simulation. The results obtained indicate a significant reduction of total harmonic distortion in output voltage and current. An algorithm has also been suggested which can be used to meet the control requirements of any levels of series connected inverters. � 2016 IEEE.