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Your search keyword '"Ahmed, Shehab"' showing total 18 results
Start Over Author "Ahmed, Shehab" Search Limiters Full Text Publication Year Range Last 50 years Journal ieee transactions on power electronics
18 results on '"Ahmed, Shehab"'

1. Novel Three-Phase Buck-Boost Inverter With Reduced Input Current Ripple and No Short-Circuit and Open-Circuit Faults

Author

Khan, Shah Nawaz, Khan, Ashraf Ali, Jamil, Mohsin, Khan, Usman Ali, Ahmed, Hafiz Furqan, and Ahmed, Shehab

Abstract

This article proposes a new single-stage three-phase buck-boost inverter and control scheme, which remarkably reduces both the low and high-frequency ripple components in the input current. The low-frequency ripple component is eliminated by phase-shifting the output three-phase voltages by 120°. The high-frequency ripple component is decreased by doubling the effective switching frequencies and lowering the voltages of the input inductors. The proposed inverter has buck-boost dc-ac conversion ability and contains only six active switches. It is short-circuiting free and can avoid the reverse recovery losses of the body diodes of the mosfets. The proposed inverter has better spectral performance and has a lower distortion in the output waveforms due to no delays (equivalent to dead-time in the traditional three-phase inverter) in the switching signals. To validate the performance and advantages of the proposed inverter, detailed analytical, simulation, and experimental results are reported. Experiments have been conducted with a 1.5-kW laboratory prototype at a 50 kHz switching frequency for the line-line output voltage of 110–220 Vrms/60. At the end, integration of inductors is also suggested to decrease the magnetic volume.

Published
2024
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6. Improved NPC Inverters Without Short-Circuit and Dead-Time Issues.

Author

Khan, Ashraf Ali, Khan, Usman Ali, Ahmed, Hafiz Furqan, Cha, Honnyong, and Ahmed, Shehab

Subjects
REACTIVE power, IDEAL sources (Electric circuits), SEMICONDUCTOR diodes, VOLTAGE, DIODES, ELECTROSTATIC induction
Abstract

The traditional neutral point clamped (NPC) inverter has short-circuit problem. The risk of short-circuit can be decreased by using dead-time in the switching signals. However, the dead-time decreases the achievable output voltage and causes distortion in the waveforms. To overcome the short-circuit problem, dual-buck NPC (DB-NPC) and split-inductor NPC (SI-NPC) inverters have been researched. However, the voltage stress of the two external diodes in the DB-NPC inverter is higher. On the other hand, the SI-NPC inverter has a problem of generating huge voltage spikes in the dead-time, which can destroy the semiconductor devices. In addition, the SI-NPC inverter cannot provide reactive power. This article presents a family of NPC inverters consisting of single-phase, three-phase, and cascaded inverters. The proposed inverters have no short-circuit and dead-time issues, therefore no high voltage and current spikes are caused. Also, the dead-time in the switching signals can be minimized. As a result, the magnitude of the output waveforms can be increased, and quality can be improved. Unlike the DB-NPC inverter, the voltage stress of all the semiconductor in the proposed inverter is lower, and unlike the SI-NPC inverter the proposed inverter provides reactive power. In this article, the proposed three-level NPC inverter is analyzed, designed, and tested. The voltage stress of the semiconductor devices in the proposed inverter is half of the source voltage, whereas in the conventional DB-NPC inverter the voltage stress of the two external diodes is the source voltage. In addition to the aforementioned benefits, the proposed cascaded inverter reduces the total number of inductors. To verify the analysis, detailed simulation, and experimental results of the proposed three-level inverter with input voltage 640 V, output power 1.2 kW, and output voltage 220 Vrms are provided. [ABSTRACT FROM AUTHOR]

Published
2022
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