In this study, a new multilevel inverter configuration which introduces a combination of cascaded H-bridge multilevel inverter with a double level circuit is proposed. The double level circuit is a half-bridge inverter when combined with a cascaded H-bridge multilevel inverter, will increase the output voltage level to nearly twice that of a conventional cascaded H-bridge multilevel inverter. The effectiveness of the proposed configuration is demonstrated with five different cases of cascaded H-bridge multilevel inverter configurations. Phase disposition carriers arrangement with sinusoidal reference has been utilised in pulse width modulation for generating the gating signal of switches to achieve high-quality output voltage waveform. A comparison is carried out with different parameters such as %total harmonic distortion, distortion factor, the maximum voltage step of output voltage level and peak inverse voltage. Analysis of power loss and theoretical calculation of %total harmonic distortion is described. Also, a new method for calculating the overall component count is discussed. As a result, the proposed configuration requires lesser component count for generating higher output voltage level with lower %total harmonic distortion. Selected simulation and experimental results are shown to verify and validate the proposed multilevel inverter configuration. © The Institution of Engineering and Technology.

Palanisamy K

Department of Energy and Power Electronics

School of Electrical Engineering

Vellore Campus

Prabaharan N

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

IET Power Electronics

In this paper, a multisource switched capacitor based boost multilevel inverter is proposed. The proposed topology features less number of components, high gain, self-charging capability of capacitors, reduced size of filter components. The modes of operation of the proposed converter and design guidelines of converter components are discussed. A comprehensive comparative study of the proposed converter topology with the topologies in the literature is given. Analytical expression for capacitor energy utilization (CEU) factor for the proposed topology is derived and the feasibility of the proposed converter with respect to CEU for the designed power rating is verified. The analytical performance of the proposed converter topology is verified through simulation studies. The common mode voltage and leakage current in the proposed topology are analyzed. Experimental prototype of the proposed converter topology with two sources and two capacitors for power rating of 500 W is developed and tested with resistive, inductive, and nonlinear loads. The experimental and simulated results are in close agreement with the analytical steady-state performance of the proposed converter. © 1986-2012 IEEE.

IEEE Transactions on Power Electronics

Multisource Switched Capacitor Based Boost Multilevel Inverter for Photovoltaic-Based Systems

Multilevel inverters (MLIs) are gaining familiarity in industries for high-voltage applications. This study is a comparison of symmetric and asymmetric reduced switch MLI topologies which require a lesser number of switches for generating the desired number of voltage levels. In both symmetric and asymmetric conditions, output voltage levels are generated using the same number of switches with different DC source magnitudes. Unipolar pulse width modulation strategy is adapted in these topologies to generate the switching pulses. Three different unipolar references (sine, trapezoidal, 60°) and three different carrier arrangements (phase disposition, alternative phase opposition and disposition and variable frequency) are taken and each reference is compared with three different carrier signals. The performance parameters such as total harmonic distortion (THD), crest factor and distortion factor are evaluated for different modulation indices and compared with both conditions. The proposed topology in symmetric and asymmetric conditions can generate 9-level and 31-level output voltages, respectively, which are simulated using MATLAB/Simulink and verified with the experimental setup. The calculation of%THD using analytical asymptotic formula is also carried out. The theoretical value of%THD is verified to match closely with the simulation and experimental results. © The Institution of Engineering and Technology 2016.

Comparative analysis of symmetric and asymmetric reduced switch MLI topologies using unipolar pulse width modulation strategies

This paper proposes a single phase multilevel inverter configuration that conjoins three series connected full bridge inverter and a single half bridge inverter for renewable energy application especially photo-voltaic system. This configuration of multilevel inverter reduces the value of total harmonic distortion. The half bridge inverter utilized in the proposed configuration increases the output voltage level to nearly twice the output voltage level of a conventional cascaded H-bridge multilevel inverter. This higher output voltage level is generated with lesser number of power semiconductor switches compared to conventional configuration, thus reducing the total harmonic distortion and switching losses. The effectiveness of the proposed configuration is illustrated by replacing the isolated DC sources in multilevel inverter with individual photo-voltaic panels using separate perturb and observer based maximum power point tracking and boost converters. The verification of the proposed system is demonstrated successfully using MATLAB/Simulink based simulation with different irradiation and temperature conditions. Also, the transient operation of the system is verified with results depicted using step change in standard test condition. In the proposed system, total harmonic distortion of the output voltage is 9.85% without using passive filters and 3.91% with filter inductance. Theoretical calculation of the power losses and total harmonic distortion with mathematical equations are discussed. Selective experimental results are presented to prove the effectiveness of proposed system. © 2016 Elsevier Ltd

Journal	IET Power Electronics
Publisher	Institution of Engineering and Technology (IET)
ISSN	1755-4535
Open Access	No