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In this paper, a nine-level inverter topology is proposed with the least number of switches and other components for fault tolerant (FT) operation. The proposed fault tolerant topology requires only one additional switch to execute the fault tolerant operation. The proposed topology also results in reduced total harmonic distortion (THD) as compared with other reported fault tolerant topologies for a 9-level output. A detailed analysis of the topology is presented and the fault tolerant operation is demonstrated under any single, double, triple, and quadruple switch faults using MATLAB/ Simulation and OPALRT hardware in loop (HIL) real time simulator. The proposed concept is validated for single and multiple switch faults and R-L load variation on a low scale laboratory hardware set-up. [ABSTRACT FROM AUTHOR]

This paper presents an investigation on mitigation of current harmonics, using Cascaded H-bridge Multilevel Converter (CHB-MLC)-based Shunt Active Power Filter (SAPF). Development and analysis of SAPF for harmonic compensation in distribution network for power quality improvement has been discussed. In the proposed work, transformer-less CHB MLC is used which reduces weight and cost of the system. Moreover, a novel controller based on average power method is adopted for generation of compensation active filter current. In order to generate switching signals, multi-carrier Alternate Phase Opposition Disposition (APOD) — Pulse Width Modulation (PWM) schemes are used. The proposed CHB-MLC SAPF reduces the source current THD below 5%. The results are simulated in MATLAB/Simulink and demonstrate the effective mitigation of current harmonics with APOD-PWM schemes. Opal-RT OP4500 real-time digital simulator is used to validate the proposed scheme under different steady state and transient conditions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

Renewable energy systems have developed wide interest to supply electricity in remote areas as well as for distributed power generation particularly during peak loads. Fuel-cell-based power generation is also gaining popularity in residential applications as well as distributed power generation due to its cleanliness, portability, and suitability for electricity and heat generation. Development of a suitable power electronic interface to make the technology viable is still a challenge. This paper presents modeling, simulation, and experimental study of a fuel cell (FC) power plant (FCPP) suitable for stand-alone application as well as for microgrid/grid interface. A single-stage pulsewidth modulation inverter is selected as power electronic interface between FC and grid. A mathematical model is developed in per unit system to define the power limits in terms of FC, converter, and power system parameters. The simulation model is developed in MATLAB environment with control scheme implementation in \ssi qd reference frame for investigation. A prototype of single-stage FCPP is developed in the laboratory to validate the results. [ABSTRACT FROM AUTHOR]