Krishna Kumar Gupta

Multilevel Inverter Topologies With Reduced Device Count: A Review

Multilevel inverters have created a new wave of interest in industry and research. While the classical topologies have proved to be a viable alternative in a wide range of high-power medium-voltage applications, there has been an active interest in the evolution of newer topologies. Reduction in overall part count as compared to the classical topologies has been an important objective in the recently introduced topologies. In this paper, some of the recently proposed multilevel inverter topologies with reduced power switch count are reviewed and analyzed. The paper will serve as an introduction and an update to these topologies, both in terms of the qualitative and quantitative parameters. Also, it takes into account the challenges which arise when an attempt is made to reduce the device count. Based on a detailed comparison of these topologies as presented in this paper, appropriate multilevel solution can be arrived at for a given application.

A Novel Multilevel Inverter Based on Switched DC Sources

This paper presents a multilevel inverter that has been conceptualized to reduce component count, particularly for a large number of output levels. It comprises floating input dc sources alternately connected in opposite polarities with one another through power switches. Each input dc level appears in the stepped load voltage either individually or in additive combinations with other input levels. This approach results in reduced number of power switches as compared to classical topologies. The working principle of the proposed topology is demonstrated with the help of a single-phase five-level inverter. The topology is investigated through simulations and validated experimentally on a laboratory prototype. An exhaustive comparison of the proposed topology is made against the classical cascaded H-bridge topology.

Theoretical analysis and experimental validation of a novel multilevel inverter topology for renewable energy interfacing applications

This paper presents a new topological structure for symmetrical cascaded multilevel inverters. The proposed circuit consists of cross-connected separate symmetrical DC sources which can generate number of levels equal to that of a cascaded H-bridge topology with reduced number of power switches. It is especially suitable for utility interfacing of renewable energy sources. It also offers the possibility of a transformer less and filter less operation. The working principle of the proposed topology is explained with the help of a single-phase five level inverter. Simulation results are obtained in matlab/simulink environment and are verified experimentally on a laboratory prototype. An exhaustive comparison of the proposed topology is made with the classical cascaded H-bridge topology, especially with the considerations of conduction losses and cost-effectiveness. The proposed topology results in the reduction of number of power switches, losses, installation area, and converter cost and thus can be implem...

A new seven-level hybrid inverter

Multilevel inverters (MLIs) have been increasingly implemented for high power DC-AC conversion. Recently, avenues are also being explored to employ MLIs for low power applications. However, for increased number of levels, component count remains a challenge. In this paper a new hybrid inverter is proposed which utilizes six active switches along with asymmetric source configuration to synthesize 7-level waveform. A cascaded H-bridge inverter with similar source configuration would require eight active switches, all operating at high switching frequency. A modulation procedure is proposed using which the switches with highest blocking voltages operate at fundamental frequency. Working of the proposed inverter is explained and concepts are validated with simulation and experimental results.

Architecture and configuration of electrified vehicles: A review

In recent years, growing concerns about environmental protection, stringent emission regulation and rapid depletion of available energy (fossil fuels) resources enforced to look for sustainable alternatives in automobile. In addition automobile industries are shifting towards more fuel efficient, improved performance, higher degree of reliability, safety and added comforts. Electrification of vehicles is considered to be promising technology for futures sustainable transportation system. Electric vehicular technology (EVT) which includes electric, hybrid electric, plug in and fuel cell vehicles have attracted more and more attention of researchers, automobile sectors, governments and consumers as an alternative of internal combustion engine based vehicles. In this paper a comprehensive review of electrified vehicles architecture, electric propulsion system configurations have been presented. The current status, future issues, technical challenges and market penetration have been discussed. Moreover, a brief comparison among different vehicle technology has also been presented.

Power electronic interface for vehicular electrification

Electrification of vehicles is considered a promising technology for future sustainable transportation system. Electric, hybrid electric, and fuel cell vehicles have attracted attention of researchers, automobile manufacturers, governments and consumers as an alternative of internal combustion engine based vehicles. Electrification of vehicular technology (EVT) depends on suitable integration of electrical, mechanical, chemical and electronics engineering. Thus the integration of different components from different fields is a major challenge and is a growing concern in the roadmap of vehicle electrification. Power electronic converters and switches are playing a very significant role in incorporating different components and provide compatibility for proper coordination among them to meet vehicles requirement in all driving profiles. In this paper, important issues related to power electronic converters as heart of electric propulsion system are presented. To study the responsibility of power electronics converters, architecture of different electrified vehicles has been reviewed. The present status and future challenges of power electronic converters as well as electric propulsion system are discussed briefly.

A switched-capacitors based multilevel boost inverter with single input source

This paper proposes a novel hybrid topology for multilevel inverters with the capability of boosting the input voltage. The proposed structure permits use of single input DC source for multilevel voltage generation at the output. It combines a switched capacitor part with an H-bridge part along with an auxiliary switch. Operation of the topology is explained with the help of a single source five-level boost inverter. An appropriate control scheme is described and simulation results are presented. A comparison with the conventional topologies is also presented in the paper. It seen that the proposed topology requires lesser number of components for higher number of levels and would be less costlier and effective in terms of overall volume.

A new topology of transistor clamped 5-level H-Bridge multilevel inverter with voltage boosting capacity

Multilevel converters are well suited for medium and high power applications because of its characteristic of synthesizing a sinusoidal voltage on several DC levels. They give good quality output resulting with lower harmonic distortion in the output and lower commutation losses. The main disadvantage is their complex circuit configurations, requiring a great number of power devices and passive components, and a complex control circuitry. A new topology of multilevel inverter for 5-level using the Conventional H-Bridge is proposed in this paper. The proposed topology is referred as new TCHB has the feature like boost output voltage capability along with capacitor voltage balancing. The proposed multilevel inverter uses four auxillary switches and transistor clamped H-bridge (TCHB) with an bidirectional switch. The single cell of conventional H-bridge produces three-level output voltage similar to input DC voltage but the single cell of proposed topology produces five-level output with output voltage double the input DC voltage. The proposed new TCHB and old TCHB 5-level inverter are modeled and simulated on matlab/simulink and compared in terms of the output voltage, total harmonic distortion (THD), No. of switching devices used etc. From the results the proposed inverter provides more output voltage with less harmonics in the output voltage.

Basics of Multilevel Inverters

This chapter introduces you to the “concept” of multilevel inverters. This concept is best understood with the example of so-called cascaded H-bridge topology. In addition, other conventional topologies are also discussed in this chapter, along with the respective modulation schemes employed for these topologies.

Basics of Inverters

In this chapter, fundamental concepts related to power electronics and inverters are discussed. Popular terminology is defined so that understanding multilevel inverters becomes much easier.