Experimental evaluation of a new carrier-based modulation method for a three-level T-type quasi-impedance-source inverter

Quasi-impedance-source inverter topologies require the insertion of short-circuit states of the DC-link to achieve the boost feature. Unlike traditional strategies that implement full short-circuits in the legs of the inverter, new control methods based on space vector modulation (SVM) introduce these states by alternately short-circuiting the two halves of the DC-link, improving the harmonic performance and efficiency of the converter. However, because of the complexity involved in the implementation of these SVM strategies, simpler and more direct control techniques are needed. In this study, a new carrier-based strategy for the control of a three-level T-Type quasi-Z-source inverter (qZS 3L-TI), which implements the half-DC-link short-circuit states, is validated through several experimental tests under rated power conditions. The experimental results indicate that the new carrier-based technique shows improved harmonic performance, lower semiconductor stress, and a better efficiency than the traditional full shoot-through strategy. Based on these results and the simplicity of implementation, the new carrier-based control strategy proves to be a competitive alternative for the control of qZS 3L-TI.