Ahmed Abdel-Mordi Abdel-Wahed Ibrahim

Bio: Ahmed Abdel-Mordi Abdel-Wahed Ibrahim is an academic researcher. The author has contributed to research in topics: Diode. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.

Capacitor voltage balancing using redundant states of space vector modulation for five-level diode clamped inverters

Abstract: A redundancy balancing technique for the five-level diode-clamped inverter is presented, which balances the four dc-link capacitor voltages at high modulation index and high power factor. The technique is based on dividing the vector space of the five-level inverter into six two-level vector spaces. Dwell times are calculated as for conventional two-level space vector modulation, and the switching sequence is determined depending on the four capacitor voltages, using a redundant state method. The double Fourier series is used to theoretically determine the resultant spectral components. The proposed technique maintains link capacitor balance for high modulation indices, including over modulation, irrespective of the power factor. The proposed algorithm is validated by simulation and practically.

Switched mode power supplies for charge-up, discharge and balancing dc-link capacitors of diode-clamped five-level inverter

Abstract: Inductor switch mode power supplies (SMPS) operated in a discontinuous inductor current mode are used to balance the dc-link capacitor voltages of a diode-clamped five-level inverter The SMPS concept is extended to charge up and discharge the four dc-link capacitors Complete diode-clamped five-level inverter operation is implemented, from start-up, charge-up, balance dc-link capacitors in normal operation, discharge, to shut-down, which have not been presented before Ramped start of a controlled rectifier sourcing a boost converter limits the lowest dc-link capacitor inrush current and control its charging time SMPS in conjunction with the boost converter are used to control the dc-link capacitor charge-up and discharge times The proposed inverter complete operation is validated by simulation and practically

Extend the Use of Auxiliary Circuit to Start up, Shut down, and Balance of the Modified Diode Clamped Multilevel Inverter

Abstract: The diode clamped multilevel inverter (DCMLI) is an attractive high voltage multilevel inverter due to its robustness The main draw back of the DCMLI is dc link capacitor voltage imbalance A diode clamped inverter has been used in this research The method used to balance the dc link capacitors is based on auxiliary switch-mode circuits, which are operated in a discontinuous inductor current mode This research is focused on how to use auxiliary SMPS circuits to start up, balance, and shutdown the inverter These functions are an issue in high voltage applications of the multilevel inverter Simulation and experimental results are presented for the proposed auxiliary circuits operational technique

Solar-powered Five Level Output Voltage of DC-TO-AC Converter Using Simplified Capacitor Voltage Controlled Scheme (SCVCS)

Abstract: This paper presents a solar-powered five level output voltage of a DC-to-AC converter using simplified Capacitor Voltage Controlled Scheme. It is configured by the combination of thin-film silicon Photovoltaic panels, insulated gate bipolar transistors, capacitors, power diodes and boost converter. A boost converter in-conjunction with PI controller ensures voltage balancing across the input DC series-connected capacitors. The system possesses the following characteristics: (i) it is portable (ii) it has very low total harmonic distortions (iii) It is cheap and simple to design. (iv) It utilizes single DC source. (v) It uses capacitors with appreciable capacitances (vi) the solar panels used are shadow tolerant due to the design of the thin-film silicon module. The following results were obtained: Stabilized five level output voltage inverter with THD of 0.95% and modulation index of 0.9. Power rating of 2.0 kW at a time interval of 0 ⩽ t ⩽1.8 seconds. The MatLab/Simulink software was used in this work.

A new SVM-based voltage balancing method for five-level NPC inverter

Abstract: This paper presents a new voltage-balancing method of five-level neutral-point clamped inverter, based on space-vector modulation redundant switching states. The proposed method uses measurement of DC-link capacitors and output phase currents in order to determine the best fitted redundancies. Due to its severe approach, the proposed method provides relatively low voltage ripples using low-capacitance DC-link capacitors. This advantage leads to reduction in size of the inverter and cost of manufacturing. Finally, some simulations in MATLAB/Simulink environment have been done in order to validate the dynamic performance of the proposed method.