An improved switched‐ladder bidirectional multilevel inverter: Topology, operating principle, and implementation

Abstract

Multi‐level inverters (MLIs) for medium or high power and voltage utilization have acceptable application in industry and are utilized commercially. The performance of MLIs is considerably preferable to traditional two‐level inverters due to their negligible harmonic content, small filter size, utilization of lower‐rated voltage devices, low electromagnetic interference (EMI), and so on. However, in the face of these many advantages, few disadvantages can be expressed such as more device count and a sophisticated control strategy. This paper presents an improved switched‐ladder topology to enhance the performance of multi‐level inverters by improving the above drawbacks. Compared to existing inverter topologies, the proposed extendable diode‐containing bidirectional structure requires fewer switches and driver circuits. The proposed topology is compared with other similar topologies, and its superiority is examined. Fundamental switching frequency modulation technique is utilized to obtain high‐quality output voltage waveforms with lower harmonic contents and reduced switching losses. This converter, despite the use of diodes, can supply the low power factor inductive‐resistive loads, bidirectionally. To demonstrate the performance of the proposed topology, in addition to simulation with the nearest level modulation technique, a prototype of the proposed structure has been implemented and tested. The results display the proper performance of the proposed topology in the real‐time environment.

A novel bidirectional modular multilevel inverter utilizing diode‐based bidirectional unit

“…Despite this, in the asymmetric topology, the voltage stress and loss of the switches are high, and the power distribution on the switches is unequal. 7,8 Novel structures have been proposed to address the challenges of traditional MLIs, some of which are listed below.…”

“…The size of voltage sources in the asymmetric method is selected unequally to increase the number of voltage levels and to reduce the switching devices. Despite this, in the asymmetric topology, the voltage stress and loss of the switches are high, and the power distribution on the switches is unequal 7,8 . Novel structures have been proposed to address the challenges of traditional MLIs, some of which are listed below.…”