Analysis and implementation of a new asymmetric double H‐bridge multilevel inverter

Abstract

Multilevel inverters (MLI) have become an integral component in many industrial applications including drive systems and distributed generation grid integrated systems. Efficient and cost-effective MLI topologies are required to enhance the performance of industrial systems. In the present work, an asymmetric double H-bridge MLI is proposed, which incorporates and enhances the attributes of a modified T-type converter and produces a superior output voltage waveform with the lesser component requirement. The proposed MLI can generate a 15-level output. An extendable generalized topology (cascaded) based on the proposed configuration has also been proposed. The topology is compared with recently introduced MLI topologies based on various performance parameters, and results are presented. The output voltage control is achieved using nearest level control which is a low switching frequency modulation technique for lowering the switching losses in the inverter. The hardware is realized, and performance is evaluated under different dynamically changing loading conditions.

An extendable asymmetric boost multi‐level inverter with self‐balanced capacitors

“…1,2 The MLIs are generally categorized into three main types: (1) Diode-Clamped MLIs (DCMLIs), (2) Flying Capacitor MLIs (FCMLIs), and (3) Cascaded MLIs (CMLIs). [3][4][5][6][7] The DCMLIs and FCMLIs usually require single DC source, which is the main advantage of these converters that leads to less cost and size. On the other hand, the DCMLIs require large number of clamping-diodes and DC-link capacitors especially at increased number of steps, where the natural voltage balancing of capacitors is not provided.…”

“…Furthermore, the requirement of a voltage sensor for each capacitor is another drawback of DCMLIs. 7 Similarly, the FCMLIs utilize numerous flying capacitors and semiconductors to achieve large number of levels. Due to different voltage of flying capacitors at different cells, bulky and expensive capacitors are required.…”

“…Due to different voltage of flying capacitors at different cells, bulky and expensive capacitors are required. 7 The CMLIs have usually simple and modular structure with no-need to voltage/current sensors. On the other hand, these converters require several DC sources to produce increased levels, which in return results to increased total size, weight and cost.…”

“…The inherent advantages of Multi‐Level Inverters (MLIs) such as suitability for high/medium voltage/power applications, modularity, low voltage stress (VS) on semiconductors, high power quality, low Total Harmonic Distortion (THD), low dv / dt resulting to reduced Electro‐Magnetic Interferences (EMIs) and low switching frequency have attracted the attention of industry and research communities 1,2 . The MLIs are generally categorized into three main types: (1) Diode‐Clamped MLIs (DCMLIs), (2) Flying Capacitor MLIs (FCMLIs), and (3) Cascaded MLIs (CMLIs) 3–7 . The DCMLIs and FCMLIs usually require single DC source, which is the main advantage of these converters that leads to less cost and size.…”

“…Thus, complicated strategies are necessary for balancing the voltage of DC‐link capacitors. Furthermore, the requirement of a voltage sensor for each capacitor is another drawback of DCMLIs 7 . Similarly, the FCMLIs utilize numerous flying capacitors and semiconductors to achieve large number of levels.…”