Forced redundant states of 5-level single-phase diode-clamped multilevel inverters

There is always a need to create efficient and optimized converters to deliver the best possible results to achieve a better THD profile in the waveform output. One way is by controlling the switching of the power switches of the converters using appropriate modulation schemes. While numerous works have been done in proposing new switching modulation strategies for multilevel inverters, this work will compare multicarrier PWM and near-to-level control (NLC) modulation schemes. In this paper, multicarrier PWM variants, namely, PD-PWM, POD-PWM, and APOD-PWM, are designed and simulated. Their voltage THD and spectrum performance are discussed when applied to single-phase 7, 9, and 11-level cascaded multilevel inverters. Then NLC modulation will be designed and applied to similar multilevel inverter circuits. It will be shown that the NLC exhibits some superior performances compared to PWM-based but with several drawbacks that can be optimized.

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Discrete current control of single-phase cascaded multilevel inverters operating with SHE-PWM

2017 IEEE Southern Power Electronics Conference (SPEC) ◽

10.1109/spec.2017.8333632 ◽

2017 ◽

Author(s):

Fabricio Hoff Dupont ◽

Junior Romani

Keyword(s):

Single Phase ◽

Current Control ◽

Multilevel Inverters

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Standalone Operation of Modified Seven-Level Packed U-Cell (MPUC) Single-Phase Inverter

Electronics ◽

10.3390/electronics8030268 ◽

2019 ◽

Vol 8 (3) ◽

pp. 268 ◽

Cited By ~ 2

Author(s):

Ali Shojaei ◽

Bahram Najafi ◽

Hani Vahedi

Keyword(s):

Output Voltage ◽

Single Phase ◽

Multilevel Inverter ◽

Switching Frequency ◽

Voltage Waveform ◽

Multilevel Inverters ◽

Design Considerations ◽

Single Phase Inverter ◽

Load Types ◽

Switch Voltage

In this paper the standalone operation of the modified seven-level Packed U-Cell (MPUC) inverter is presented and analyzed. The MPUC inverter has two DC sources and six switches, which generate seven voltage levels at the output. Compared to cascaded H-bridge and neutral point clamp multilevel inverters, the MPUC inverter generates a higher number of voltage levels using fewer components. The experimental results of the MPUC prototype validate the appropriate operation of the multilevel inverter dealing with various load types including motor, linear, and nonlinear ones. The design considerations, including output AC voltage RMS value, switching frequency, and switch voltage rating, as well as the harmonic analysis of the output voltage waveform, are taken into account to prove the advantages of the introduced multilevel inverter.

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Normally Bypassed Cascaded Sources Multilevel Inverter with RGA Optimization for Reduced Output Distortion and Formulaic Passive Filter Design

Journal of Circuits System and Computers ◽

10.1142/s021812662050019x ◽

2019 ◽

Vol 29 (02) ◽

pp. 2050019

Author(s):

G. Chitrakala ◽

N. Stalin ◽

V. Mohan

Keyword(s):

Distributed Generation ◽

Single Phase ◽

Filter Design ◽

Circuit Complexity ◽

Optimization Scheme ◽

Dc Voltage ◽

Multilevel Inverters ◽

Harmonic Content ◽

Lc Filter

The distributed generation involving multiple photovoltaic sources and synthesizing high-quality ac voltage from those multiple dc sources are nascent research ambits. A host of multilevel inverters (MLIs) has been ascertained for performing above errand diligently, where the component count is obnoxious. The single phase seven-level inverter is an acquiescent compromise between the circuit complexity and the quality of the output. Further enhancement on the performance can be succored through optimizing dc link voltages and switching angles. This paper proposes a component count pruned MLI structure and also a refined genetic algorithm (RGA)-based optimization scheme for the computation of both dc link voltages and switching angles. Previous attempts for this problem have solved the switching angles with the objective of resulting minimum harmonic content in the staircase-shaped output voltage. The dc link voltage of each level is however assumed to be the same and constant. As an extension, RGA-based optimization of both dc link voltages and switching angles is triumphed. The harmonic profile of the proposed switching strategy is simulated and also corroborated by a hardware prototype. In practice, the proposed fundamental switched strategy is apposite, in which each dc voltage can be self-maintained and independently controlled. In addition, a method for designing the passive LC filter is also presented.

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