Jesus Silva-Rodriguez graduated with a B.S. in Electrical Engineering from the University of Houston, and started his PhD program here as a direct PhD student in January 2021. During his undergraduate studies, Jesus was a recipient of the DAAD RISE Scholarship in 2019 and participated in a research internship at the Technical University Dortmund, Germany, performing feasibility studies to develop simulation models for a Pulse Electroacoustic (PEA) cell, used in the detection of space charges in insulating materials for High Voltage DC applications. Currently, Jesus is pursuing his PhD in Electrical Engineering focusing in optimization models for the water-energy nexus for small communities, as well as microgrid energy management and power systems operations.
Rida Fatima received her bachelor’s degree in electrical engineering from Mirpur University of Sciences and Technology, Azad Kashmir, Pakistan in 2015 and her master’s degree in electrical engineering – Power from National University of Sciences and Technology, Islamabad, Pakistan in 2018. She has worked as a Research Associate at TetraTech: Consulting and Engineering Firm. from 2019 to 2021, specializing in Renewable Energy Markets and Policies. She is currently working towards her Ph.D. degree in Electrical Engineering at the University of Houston, Houston, TX, USA. Her research interests include Smart grids, Energy Markets, and the optimization of Distribution Networks.
Massiagbe Diabate received her bachelor’s degree in Electrical Engineering in 2021 and her master’s in Electrical Engineering in 2023 from the University of Houston in Texas, USA. She is currently pursuing her Ph.D. in the Department of Electrical & Computer Engineering at the University of Houston in Texas, USA. Her research interest focuses on power electronics converters for fuel cell technology, and Energy Management Systems (EMS) of Energy Storage Systems (ESSs), such as Hydrogen and Batteries for Microgrids.
Hassan received his bachelor’s degree in Electrical Engineering from Air University, Islamabad, Pakistan in 2016 and master’s degree in Electrical Engineering – Power from National University of Sciences and Technology, Islamabad, Pakistan in 2019. He has worked as a R&D Engineer in SkyElectric Pvt. Ltd. from 2019 to 2022, specializing in Li-Ion based Battery Energy Storage Systems (BESS). He is currently working towards his Ph.D. degree in Electrical Engineering at the University of Houston, Houston, TX, USA. His research interests include Microgrid Optimal Sizing & Optimal Energy Management Strategy involving BESS.
Ann received her Bachelor’s degree (B.Tech) in Electrical and Electronics Engineering from University of Kerala in 2017 and a Master’s degree (M.S.) in Electrical Engineering from Rochester Institute of Technology in 2022. From 2017 to 2020, she worked as an Electrical Engineer for CKR Consulting Engineers in Dubai, UAE. She is currently working towards her Ph.D. in Electrical Engineering at the University of Houston. Her research interest includes microgrid optimal sizing and energy management, grid integration of renewable generation, demand side management and battery storage system planning.
High voltage direct current (HVDC) transmission system in the subsea industry is being considered as an efficient power transmission solution as the number of power conductors and the reactive power consumption are minimal. However, one of the key challenges in HVDC transmission systems lies in the lack of reliability against short circuit faults. Serious faults can generate surge currents more than one hundred times the normal operating currents. These faults can result in damage to expensive equipment if circuit breakers (CBs) are not fast enough and rated for such a high level of faults. For offshore HV transmission systems, the cost of an unplanned outage as a result of a fault on a HVDC export cable is typically 10-fold to 100-fold the cost of the same failures in onshore HV networks. In view of this, it is desirable to introduce a reliable means of limiting the fault currents so that the CBs open at lower fault currents without any damage.
Resistive-type superconducting fault current limiters (R-SFCLs) made with high-temperature superconducting (HTS) tapes are expected to be the most effective, small-sized and offer reliable protection against such faults due to high critical current density and quick superconducting to normal-state transition. In this project, the fault current limiting performance of DCCB topology, without and with R-SFCL integration, is obtained. Further, the response time of various CB topologies like MCB, Resonant CB (RCB), IGBT based HCB (similar to ABB topology) and thyristor based CIHCB (also called DCCB topology) are also investigated. The integration of R-SFCL decreases the peak current flowing through the breaker, and this enables reduction in the size of breaker. Further, the power loss of CBs for different response time of R-SFCL is analyzed to select the superconductors for R-SFCL and suitable CB topology for future subsea HVDC power transmission systems.
Nearly 1,500 oil and gas (O&G) rigs are located offshore across the globe, the largest share of which are in the North Sea and Gulf of Mexico. The recent trend in O&G industry is to install the subsea processing loads on the seabed for reducing the required space on the platform or even removing the platform altogether. The subsea processes (or subsea factory) include gas compression, boosting, water injection, and separation. Typical power consumption of the Subsea loads is in the range of 5-300 MW, traditionally supplied by local gas turbines or diesel generators. Such power generation strategies have led to significant increase in greenhouse gas emissions. Also, the electric distribution system of O&G platforms is characterized as a weak electric grid, resulting in poor power quality, lower power factor, voltage and current harmonics, voltage notches, and common mode voltages. All these result in increased losses and also affect the long-term reliability.
Block diagram of the system for integration of renewable energy sources
This project proposes a system of Multi-port Energy Routers using Intelligent Transformers (MERIT) to interface renewable resources and subsea O&G factories with the HVDC (or MVDC) Grid. In this project, we will investigate combining the energy from wind, wave, floating PV panels and fuel cell – based generators, all located near the subsea factories, to power the loads. Intelligent power converters, including solid state transformers (SSTs), are critical to enhance the power density, reliability and efficiency of the proposed MERIT system. SSTs enable seamless interconnectivity and interoperability between the various energy sources. SSTs support features such as instantaneous voltage compensation, power outage compensation, fault isolation, bi-directional power flow, etc. This research will also investigate how to optimally design and integrate SSTs into the MERIT system to have the best performance both during transient and steady state conditions. It is expected that widespread implementation of the proposed synergies can lead to over 50 % reduction in emissions.
As one of the foremost requirements of a subsea power delivery system is reliability, HVDC protection units must conform to extremely stringent specifications in terms of fault interruption time and fault level. However, a major challenge in the growth of DC power market is the lack of reliable protection against short-circuit faults. A fault in a DC system results in fast ramp up of the fault current. Moreover, DC fault current does not experience any natural zero-crossing. Therefore, DC circuit breakers (DCCBs) should be capable of fast fault quenching in order to prevent damage to the DC system and maintain grid resiliency. Additionally, a DCCB should operate with minimal power loss as a closed switch. Fault interruption using a DCCB causes enormous energy dissipation and voltage stress. If a DC fault current is 4-5 times higher than the rated DCCB, then it cannot work efficiently without expanding its components. Therefore, the use of a fault current limiter is essential, and the superconducting fault current limiter (SFCL) is the most promising choice together with a fast-switching DCCB in series. Resistive type superconducting fault current limiter (R-SFCL) is one of the most ideal, compact, small size current limiting devices to protect the power system and electrical equipment. It can limit the fault current effectively in power systems where CBs can work safely and prevent damage to the circuit components within several milliseconds.
This research work is mainly focused on identifying the individual components in a hand-drawn schematic diagram, and thus performing simulative analysis of a power converter. YOLOR (You Only Learn One Representation) – the state-of-the-art deep learning-based object detection model is used to detect the electronic components i.e. resistor, capacitor, diode, etc. in a circuit diagram. A Hough transform algorithm is used to trace the horizontal and vertical wire connection, whereas KMeans clustering is used to segregate the points-of-intersection between those horizontal and vertical lines to identify the nodes in the circuit. By using all of this circuit information, a netlist of the circuit is generated – that can be fed into any spice-based circuit simulators. In this work, PySpice – an open-source python module, is used to auto-simulate the identified hand-drawn schematic diagram. In future, this work will be extended to automate the PCB design of the detected hand-drawn circuit diagram. The overall workflow algorithm of this research work is as depicted in the flowchart.
Proposed method for the automated simulation of a hand-drawn schematic of the power converters
Wireless communication uses radio frequency power amplifiers (RFPAs) to amplify the signal before transmitting. Traditional RFPAs in communication base stations use fixed voltage DC power supplies. For the communication signal with high peak to average power ratio (PAPR), linear RFPAs will be inefficient and excess power will dissipate as heat. Therefore, a larger cooling system will be required and make communication base station system bulky. To improve the efficiency and miniaturize the system, envelope tracking power supplies are being used. Envelope tracking (ET) power supply utilize envelope extractor to obtain the envelope of the transmitted signal waveform. The output voltage is modulated to track the envelope of communication signal and supply the RFPAs. Communication signal will be distorted if the converter switching frequency is less than signal bandwidth. Thus, ET power supplies are required to switch at several tens of MHz for 4G/5G signals.
This project involves technology that will improve the converter system’s power density, efficiency, and operational life across pulsed power applications such as healthcare tech (e.g., MRI) and water purification; where the miniaturized size of the system will also disruptively reduce the cost of downhole well logging tools used in fossil and geothermal energy production. The project is funded by the U.S. Department of Energy’s Advanced Research Projects Agency with a $1 million grant for three years starting in April 2022. Part of the project will include designing a DC-DC converter with a few Kilowatts and the capability to work with high-temperature operations up to 175 degrees Celsius for downhole tools to perform sub-surface characterization and the other part involved power converter development for MRI application.
