Analysis of Controlled Diode Bridge Clamped based 3L-VSI using Space Vector approach

In this paper, some important aspects related to operating modes, dead time in inverter switches, merits, demerits and PWM technique implementation of controlled diode bridge clamped based 3L-VSI is discussed in detail. A high-frequency PWM technique based on the principle of space vector concept is used for the analysis of switching states. Two main type of switching techniques based on space vector approach namely, continuous and discontinuous PWM techniques have been used. For the discontinuous PWM sequence, the main focus here is to accurately select the switching sequence for the first switching cycle so that nearest three-level switching can be achieved without any extra switching instant over a fundamental cycle of the output voltage. Dependence of modulation index on switching states selection has been pointed out. To verify the correctness of the proposed approach, simulation and experimental results are presented.