This page has only limited features, please log in for full access.
Razzaqul Ahshan received a B.Sc. Degree in Electrical and Computer Engineering from the Khulna University of Engineering & Technology, Bangladesh, in 2002, and M.Eng. and Ph.D. Degrees in Electrical Engineering from the Memorial University of Newfoundland, St. John’s, NL, Canada, in 2008 and 2013, respectively, with a scholarship from the Natural Sciences and Engineering Research Council of Canada (NSERC). He was a Lecturer for three years with the Khulna University of Engineering & Technology, Bangladesh. In 2011, he joined the College of North Atlantic, Newfoundland, Canada, as a faculty and a researcher and served until August 2016. Currently, he is an Assistant Professor with the Department of Electrical and Computer Engineering, Sultan Qaboos University, Muscat, Oman. His research interests include electrical machines and drives, power electronic converters, renewable energy systems, microgrids, smart grids, energy management and control, energy storage, green hydrogen, system reliability modelling, digital signal processing techniques, and their applications in power systems. Dr. Razzaqul is a recipient of the Distinguished Academician Award of Sultan Qaboos University, Oman for the year 2020-2021, Fellow of the School of Graduate Studies at the Memorial University of Newfoundland, Canada, and Academic Gold Medal Award at the Khulna University of Engineering & Technology, Bangladesh.
Hydrogen production using renewable power is becoming an essential pillar for future sustainable energy sector development worldwide. The Sultanate of Oman is presently integrating renewable power generations with a large share of solar photovoltaic (PV) systems. The possibility of using the solar potential of the Sultanate can increase energy security and contribute to the development of the sustainable energy sector not only for the country but also for the international community. This study presents the hydrogen production potential using solar resources available in the Sultanate. About 15 locations throughout the Sultanate are considered to assess the hydrogen production opportunity using a solar PV system. A rank of merit order of the locations for producing hydrogen is identified. It reveals that Thumrait and Marmul are the most suitable locations, whereas Sur is the least qualified. This study also assesses the economic feasibility of hydrogen production, which shows that the levelized cost of hydrogen (LCOH) in the most suitable site, Thumrait, is 6.31 USD/kg. The LCOH in the least convenient location, Sur, is 7.32 USD/kg. Finally, a sensitivity analysis is performed to reveal the most significant influential factor affecting the future’s green hydrogen production cost. The findings indicate that green hydrogen production using solar power in the Sultanate is promising, and the LCOH is consistent with other studies worldwide.
Razzaqul Ahshan. Potential and Economic Analysis of Solar-to-Hydrogen Production in the Sultanate of Oman. Sustainability 2021, 13, 9516 .
AMA StyleRazzaqul Ahshan. Potential and Economic Analysis of Solar-to-Hydrogen Production in the Sultanate of Oman. Sustainability. 2021; 13 (17):9516.
Chicago/Turabian StyleRazzaqul Ahshan. 2021. "Potential and Economic Analysis of Solar-to-Hydrogen Production in the Sultanate of Oman." Sustainability 13, no. 17: 9516.
Permanent magnet generator (PMG)-based wind energy conversion systems (WECSs) with battery units, have become a popular class of distributed generation units. These distributed generation units are typically operated using various types of controllers, including droop controllers. Existing droop controllers are designed to operate grid-side dc-ac power electronic converters (PEC) to ensure stable and reliable power production by a PMG-based WECS. The employment of battery storage units (to mitigate fluctuations in the power produced by a PMG-based WECS) introduces additional considerations for the design of droop controllers. Such considerations are due to the power available from battery units that is dependent on the state-of-charge (SOC). This paper proposes adjustments in the parameters (droop constants) of the droop control (operate the the discharge PEC) based on the SOC of the battery units. These adjustments are made to further support stable and reliable power delivery of the PMG-based WECS into the point-of-common-coupling (PCC). The proposed adjustments of droop constants are evaluated using a 7.5 kW grid-connected PMG-based WECS with 3.52 kW generator-charged battery storage units. Performance tests are carried out for step changes in the active and reactive power demands, changes in the wind speed, and grid-side disturbances. Test results show that the proposed correction of the droop constants is critical for maintaining a stable, effective, and accurate power delivery by the battery units, thus supporting the voltage/frequency stability at the PCC under different operating conditions.
S. A. Saleh; R. Ahshan. Parameter Adjustment for the Droop Control Operating a Discharge PEC in PMG-Based WECSs with Generator-Charged Battery Units. IEEE Access 2021, 9, 1 -1.
AMA StyleS. A. Saleh, R. Ahshan. Parameter Adjustment for the Droop Control Operating a Discharge PEC in PMG-Based WECSs with Generator-Charged Battery Units. IEEE Access. 2021; 9 ():1-1.
Chicago/Turabian StyleS. A. Saleh; R. Ahshan. 2021. "Parameter Adjustment for the Droop Control Operating a Discharge PEC in PMG-Based WECSs with Generator-Charged Battery Units." IEEE Access 9, no. : 1-1.
This paper presents the development and testing of a model-predictive control (MPC) for three phase ( $3\phi$ ) transformerless grid-connected 5-level power electronic converters (PECs). The proposed MPC employs a discrete-time model of 5-level PECs to predict the future values of the grid-injected currents and ground potential. Predicted values of the grid-injected currents and ground potential are used to set the reference signals to minimize a cost function, which is formulated in terms of the command and actual grid-injected current and ground potential. The tested MPC is implemented for transformerless grid-connected diode-clamped and flying-capacitor 5-level PECs under different conditions. Test results show that the developed MPC can operate transformerless grid-connected PECs to ensure accurate, dynamic, and fast responses to changes in the power injected into the grid. Furthermore, the tested control demonstrates a good ability to minimize ground potentials during steady-state and step changes in the power delivered to/from the grid.
Saleh A. M. Saleh; Razzaqul Ahshan; Ahmed Al-Durra. Developing and Testing Model Predictive Control to Minimize Ground Potentials in Transformerless Interconnected Five-Level Power Electronic Converters. IEEE Transactions on Industry Applications 2021, 57, 3500 -3510.
AMA StyleSaleh A. M. Saleh, Razzaqul Ahshan, Ahmed Al-Durra. Developing and Testing Model Predictive Control to Minimize Ground Potentials in Transformerless Interconnected Five-Level Power Electronic Converters. IEEE Transactions on Industry Applications. 2021; 57 (4):3500-3510.
Chicago/Turabian StyleSaleh A. M. Saleh; Razzaqul Ahshan; Ahmed Al-Durra. 2021. "Developing and Testing Model Predictive Control to Minimize Ground Potentials in Transformerless Interconnected Five-Level Power Electronic Converters." IEEE Transactions on Industry Applications 57, no. 4: 3500-3510.
This paper deals with a discrete-time stochastic control model design for random failure prone and maintenance in a single machine infinite bus (SMIB) system. This model includes the practical values of failure/repair rate of transmission lines and transformers. The probability matrix is, therefore, calculated accordingly. The model considers two extreme modes of operations: the most reliable mode and the least reliable contingency case. This allows the control design which stochastically stabilizes the system under jump Markov disturbances. For adequate transient response, the proposed state feedback power system stabilizer (PSS) achieves a desired settling time and damping ratio by placing the closed-loop poles in a desired region. The control target should also be satisfied for load variations in either mode of operation. A sufficient condition is developed to achieve the control objectives via solving a set of linear matrix inequalities (LMI). Using simulation, the performance of the designed controller is tested for the system that prone to random failure/maintenance under various loading conditions. Simulation results reveal that the closed-loop poles reside within the desired region satisfying the required settling time and damping ratio under the aforementioned disturbances. The contributions of the paper are summarized as follows: (1) modeling of transition probability matrix under Markov Jumps using practical data, (2) designing a controller by compelling the closed poles into the desired region to achieve adequate dynamic performance under different load varying conditions.
Farag El-Sheikhi; Hisham Soliman; Razzaqul Ahshan; Eklas Hossain. Regional Pole Placers of Power Systems under Random Failures/Repair Markov Jumps. Energies 2021, 14, 1989 .
AMA StyleFarag El-Sheikhi, Hisham Soliman, Razzaqul Ahshan, Eklas Hossain. Regional Pole Placers of Power Systems under Random Failures/Repair Markov Jumps. Energies. 2021; 14 (7):1989.
Chicago/Turabian StyleFarag El-Sheikhi; Hisham Soliman; Razzaqul Ahshan; Eklas Hossain. 2021. "Regional Pole Placers of Power Systems under Random Failures/Repair Markov Jumps." Energies 14, no. 7: 1989.
This paper presents a dq power flow based energy storage control system for reliable and stable operation of a renewable power generation based microgrid system. The control objectives are storing the excess energy from the microgrid into the storage unit or supplying energy deficit from the storage unit to the microgrid to achieve power equity between the generation and load, and regulation of voltage and frequency during stand-alone microgrid operation. Whereas during grid-connected microgrid operation, the control objective is to ensure storing energy in the storage unit and exchange power between the microgrid and the utility grid. The proposed controller is developed for inverter interface energy storages using dq power flow. The dq power flow is formulated using bus voltage components and the bus admittance matrix in dq frame. The dq power flow in the developed controller generates command (reference) active and reactive powers for the inverter interfaced storage unit connected to the microgrid buses. In addition, the implemented current controller of the inverter assures such command powers exchange between the storage unit and the microgrid. The developed dq power flow based storage unit (DQPFSU) control system is tested under various operating conditions for both in grid-connected and stand-alone microgrid operation. The test results of the developed DQPFSU controller illustrates satisfactory performance in generating fast control actions to ensure reliable and stable microgrid operation under various changing conditions. Moreover, the validity of such control actions has examined from the frequency response and bus voltages of the case study microgrid under various tested operational conditions.
R. Ahshan; S. A. Saleh; Abdullah Al-Badi. Performance Analysis of a Dq Power Flow-Based Energy Storage Control System for Microgrid Applications. IEEE Access 2020, 8, 178706 -178721.
AMA StyleR. Ahshan, S. A. Saleh, Abdullah Al-Badi. Performance Analysis of a Dq Power Flow-Based Energy Storage Control System for Microgrid Applications. IEEE Access. 2020; 8 (99):178706-178721.
Chicago/Turabian StyleR. Ahshan; S. A. Saleh; Abdullah Al-Badi. 2020. "Performance Analysis of a Dq Power Flow-Based Energy Storage Control System for Microgrid Applications." IEEE Access 8, no. 99: 178706-178721.
This paper aims to develop models for the ground potentials in transformerless grid-connected multi-level power electronic converters (PECs). These PECs are widely used in photovoltaic systems, motor drives, and solid-state power transformers, where they offer reduced input and output harmonic distortions. The desired models for ground potentials are constructed based on common-mode voltages across each leg of the multi-level PECs. The constructed models for ground potentials are to be used for creating local grounding, along with designing adequate grounding circuits for transformerless grid-connected multi-level PECs. An adequate local grounding (for transformerless grid connected PEC) ensures blocking ground currents from flowing through the host grid grounding, and guarantees eliminating ground potentials. The developed models and grounding circuits are evaluated for transformerless grid-connected diode-clamped, flying-capacitor, and cascaded H-bridge multi-level PECs under different operating conditions. Test results demonstrate the significant advantages of the adequate grounding of transformerless grid-connected PECs, in terms of reduced input and output harmonic distortion, minimized ground potentials, and improved efficiency.
Saleh A. M. Saleh; Ahmed Al-Durra; Razzaqul Ahshan. On the Ground Potentials and Grounding Circuits of Transformerless Grid-Connected Multilevel Power Electronic Converters. IEEE Transactions on Industry Applications 2020, 56, 6286 -6297.
AMA StyleSaleh A. M. Saleh, Ahmed Al-Durra, Razzaqul Ahshan. On the Ground Potentials and Grounding Circuits of Transformerless Grid-Connected Multilevel Power Electronic Converters. IEEE Transactions on Industry Applications. 2020; 56 (6):6286-6297.
Chicago/Turabian StyleSaleh A. M. Saleh; Ahmed Al-Durra; Razzaqul Ahshan. 2020. "On the Ground Potentials and Grounding Circuits of Transformerless Grid-Connected Multilevel Power Electronic Converters." IEEE Transactions on Industry Applications 56, no. 6: 6286-6297.
The Smart Grid (SG) is considered as an imminent future power network because of its fault identification and self-healing capabilities. Energy sustainability, renewable energy integration and an efficient control system are the key factors to be considered in developing SG system. Among various SG concepts, the term virtual power plant (VPP) integrates renewable energy to the grid and provides higher operational flexibility, but it requires extra capital costs for control system and software. The operational activities of a smart grid largely depend on the active customer demands. This paper defines and discusses various SG system concepts such as virtual power plant, and active demand in consumer networks, and also presents drivers and roadmaps for development of smart grids worldwide. Furthermore, this work provides an insight into present research and development on smart grids around the world, and sheds light on developing and establishing SG for the Sultanate of Oman.
Abdullah Hamed Al-Badi; Razzaqul Ahshan; Nasser Hosseinzadeh; Reza Ghorbani; Eklas Hossain. Survey of Smart Grid Concepts and Technological Demonstrations Worldwide Emphasizing on the Oman Perspective. Applied System Innovation 2020, 3, 5 .
AMA StyleAbdullah Hamed Al-Badi, Razzaqul Ahshan, Nasser Hosseinzadeh, Reza Ghorbani, Eklas Hossain. Survey of Smart Grid Concepts and Technological Demonstrations Worldwide Emphasizing on the Oman Perspective. Applied System Innovation. 2020; 3 (1):5.
Chicago/Turabian StyleAbdullah Hamed Al-Badi; Razzaqul Ahshan; Nasser Hosseinzadeh; Reza Ghorbani; Eklas Hossain. 2020. "Survey of Smart Grid Concepts and Technological Demonstrations Worldwide Emphasizing on the Oman Perspective." Applied System Innovation 3, no. 1: 5.