تصفح حسب المؤلف "Williams, B. W."
-
Capacitor voltage balancing using redundant states of space vector modulation for five-level diode clamped inverters
Hotait, H.A; Massoud, Ahmed; Finney, S. J.; Williams, B. W. ( IEEE , 2010 , Article)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 ... -
DC-link capacitor voltage balancing for a five-level diode-clamped active power filter using redundant vectors
Zhang, H. B.; Finney, S.J.; Lim, T. C.; Massoud, Ahmed; Yang, J.; Williams, B. W.... more authors ... less authors (2013 , Article)This paper investigates the compensation and modulation processes of the five- level diode-clamped active power filter, compensating a three-phase rectified resistor-inductor load with redundant vectors. From the analysis, ... -
Evaluation of a multilevel cascaded-type dynamic voltage restorer employing discontinuous space vector modulation
Massoud, A.M.; Ahmed, S.; Enjeti, P.N.; Williams, B.W. ( IEEE Industrial Electronics Society , 2010 , Article)In this paper, the application of a cascaded multilevel inverter as a dynamic voltage restorer (DVR) is investigated. Two discontinuous multilevel space vector modulation (SVM) techniques are implemented for DVR control ... -
Hybrid and modular multilevel converter designs for isolated HVDC-DC converters
Gowaid I.A.; Adam G.P.; Massoud A.M.; Ahmed S.; Williams B.W. ( Institute of Electrical and Electronics Engineers Inc. , 2018 , Article)Efficient medium and high-voltage dc-dc conversion is critical for future dc grids. This paper proposes a hybrid multilevel dc-ac converter structure that is used as the kernel of dc-dc conversion systems. Operation of the ... -
Inverter-based versus synchronous-based distributed generation; Fault current limitation and protection issues
Massoud, Ahmed; Ahmed, S.; Finney, S. J.; Williams, B. W. ( IEEE , 2010 , Conference Paper)The contribution of distributed generation (DG) to network fault levels depends heavily on the technology employed. In the case of directly connected rotating machines the fault behavior is well established; with synchronous ... -
Modular multilevel structure of a high power dual active bridge DC transformer with stepped two-level output
Gowaid, I.A.; Adam, G.P.; Massoud, Ahmed; Ahmed, S.; Holliday, D.; Williams, B.W.... more authors ... less authors ( Institute of Electrical and Electronics Engineers Inc. , 2014 , Conference Paper)This paper addresses the issues of dc voltage matching and dc fault protection in potential super-grids. An approach for high power dc-dc conversion is proposed and analyzed. A front-to-front connection of modular-multilevel ... -
Multiloop control strategy for grid-interfaced three-phase voltage source inverter with passively damped LLCL-filter
Azani, H.; Massoud, Ahmed; Ben-Brahim, L.; Williams, B.W.; Holliday, D. ( Institution of Engineering and Technology , 2014 , Conference Paper)In inverter-based distributed generation (IBDG) and similar to the conventional third order LCL filter, the high order LLCL filter is difficult to stabilize, and may cause a resonance between the inverter and the grid. ... -
New voltage regulation techniques for low voltage radial feed PWM inverter based distributed networks
Ahmed, K. H.; Massoud, Ahmed; Finney, S. J.; Williams, B. W. (2010 , Conference Paper)Grid voltage rise problems occur, especially at light loads, due to the proliferation of distributed generation. Two techniques are proposed for regulating the voltage in low voltage radial networks when inverter based ... -
Performance assessment of L-2LC-L filter (double LC trap)-based grid-connected three-phase voltage source inverter
Azani, H.; Massoud, A.; Ben-Brahim, L.; Williams, B. W.; Holliday, D. ( IEEE , 2018 , Conference Paper)Inverter-Based Distributed Generation (IBDG) units are typically coupled to the grid via three-phase Voltage Source Converters (VSCs). The IBDGs may pollute utility with the injected harmonic currents. In order to meet the ... -
Quasi two-level operation of modular multilevel converter for use in a high-power DC transformer with DC fault isolation capability
Gowaid, I. A.; Adam, G. P.; Massoud, Ahmed; Ahmed, S.; Holliday, D.; Williams, B. W.... more authors ... less authors ( Institute of Electrical and Electronics Engineers Inc. , 2015 , Article)DC fault protection is one challenge impeding the development of multiterminal dc grids. The absence of manufacturing and operational standards has led to many point-to-point HVDC links built at different voltage levels, ... -
Quasi two-level PWM operation of a nine-arm modular multilevel converter for six-phase medium-voltage motor drives
Diab M.S.; Adam G.P.; Williams B.W.; Massoud A.M.; Ahmed S. ( Institute of Electrical and Electronics Engineers Inc. , 2018 , Conference Paper)This paper proposes a hybrid converter for medium-voltage six-phase machine drive systems that mixes the operation of a traditional two-level voltage-source inverter and the modular multilevel converter (MMC) to enable ... -
Single-Stage Three-Phase Differential-Mode Buck-Boost Inverters with Continuous Input Current for PV Applications
Darwish, Ahmed; Massoud, Ahmed M.; Holliday, Derrick; Ahmed, Shehab; Williams, B.W. ( Institute of Electrical and Electronics Engineers Inc. , 2016 , Article)Differential-mode buck-boost inverters have merits such as reduced switch number, ability to provide voltages higher or lower than the input voltage magnitude, improved efficiency, reduced cost and size, and increased power ... -
Stability analysis of an active-damped LLCL filter- based grid-connected three-phase inverter
Massoud, A.; Ben-Brahim, L.; Hamid, A.; Williams, B.W.; Holliday, D. ( IEEE , 2014 , Conference Paper)Power passive filters are a standard solution for gridcurrent harmonics attenuation. However, these types of filters may cause a resonance between the inverter and the grid. Passive and active damping techniques are employed ... -
Switched mode power supplies for charge-up, discharge and balancing dc-link capacitors of diode-clamped five-level inverter
Ashaibi, A. A.; Finney, S.,J.; Williams, B. W.; Massoud, Ahmed ( IET , 2010 , Article)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 ... -
The transition arm multilevel converter - A concept for medium and high voltage DC-DC transformers
Gowaid, I.A.; Adam, G.P.; Williams, B.W.; Massoud, Ahmed; Ahmed, S. ( Institute of Electrical and Electronics Engineers Inc. , 2015 , Conference Paper)This paper proposes a dc/ac converter topology where each phase leg comprises a conventional series switch valve in one arm and a series connection of half-bridge chopper cells in the other arm. Operation with trapezoidal ...