High Reliable Medium Voltage Drive With Reduced Component Count of Converters

Abstract

The rapid development of technology, particularly in the fields of medium-voltage drive applications, has led to the widespread and use of AC to DC multi-pulse and DC to AC multilevel converters. In recent years, multi-winding transformers (MWTs)-based multi-pulse converters have received significant attention, owing to the growing need to utilize the energy as per power quality standards with high reliability in medium voltage drive systems. The main issues of multi-pulse converters are the large complexity of winding connections, which directly degrades the reliability of the system and increases the requirement for conductor material. To address these issues of grid-end converters, this paper suggests a less complex structure of a multi-winding transformer (MWT) for a thirty-six pulse AC-DC converter, which demands the least conductor material for windings. Moreover, the reduction in the number of components of the multi-level inverters has a noticeable role in saving size, cost, and reliability improvement. To address these features in the drive system, a five-level hybrid symmetric cascaded H-bridge multilevel inverter (HSCHB-MLI) is presented, which performs a high-quality power conversion at the motor terminals of the drive system. Hence, the main concerns of this drive system are the reduction in the component count, weight, and losses of the system with excellent harmonics performance. The operational aspects of the topology such as circuit structure, design, and indirect field-oriented control (IFOC), and modulation technique (parabolic carrier wave-based level shifted pulse width modulation) are elaborated in detail. A detailed comparative assessment is performed with other multi-winding transformers and multi-level inverter structures to demonstrate the merits of the presented multi-winding transformer and multilevel inverter structures, respectively. Finlay, through Simulink modeling and hardware testing setup, the viability of the proposed architecture is verified.