A new low cost cascaded transformer multilevel inverter topology using minimum number of components with modified selective harmonic elimination modulation

Abstract

In this paper, a novel cascaded transformer multilevel inverter is proposed. The number of the switching devices is reduced in the proposed topology. This topology comprises of a DC source, several single phase low-frequency transformers, two main power switches and some bidirectional switching devices. In this topology, only one bidirectional switch is employed for each transformer. However, in conventional cascaded transformer multilevel inverter, four switching devices are required for each transformer. Therefore, more output voltage levels can be obtained using fewer switching components. Reduction in the number of switching devices which also means reduction in the number of gate drivers results in smaller size and low implementation cost. Switching power losses are also reduced in this topology. Selective harmonic elimination (SHE) technique is applied to the proposed inverter to obtain a high quality output voltage. Simulation and experimental results are also provided to verify the feasibility of the proposed converter.Ó 2014 Production and hosting by Elsevier B.V. on behalf of Ain Shams University.

Simplified transformer‐based multilevel inverter topology and generalisations for renewable energy applications

“…• Type 1: The value of q changes as shown in (22) and from (6) maximum value of q is six, to get uniform levels in the output voltage…”

“…In this section, the benefits of the proposed MLI topology are elucidated by comparing it with those recently presently topologies in [18][19][20][21][22][23] and the ensuing results are shown.…”

“…The authors of [23] require a lesser number of switches compared to the proposed inverter. For instance, with 12 switches, proposed inverter and CHB trinary generates 27L output voltage but [18][19][20][21][22] and transformer CHB MLI in binary configuration generate only 11,25,19,25,11, and 15 level output voltage, respectively.…”

“…In recent years, valuable research efforts are focused on reducing the number of components required in MLIs. An outcome of such effort can be witnessed in the form of wide-ranging MLI topologies and control strategies as reported in [18][19][20][21][22][23]. The topology in [18] capable of operating in symmetric configuration alone requires ten switches, four transformers and a single dc source for a nine-level (9L) output voltage.…”

Modular multilevel inverter for renewable energy applications

“…The cascaded H Bridge MLI further divided in to symmetrical and asymmetrical type [9,10]. In the first type all the DC input voltage source used has the same amplitude.…”