Atif Maqsood
Clemson University
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Publication
Featured researches published by Atif Maqsood.
IEEE Transactions on Power Electronics | 2016
Atif Maqsood; Allan Overstreet; Keith Corzine
The Z-source dc circuit breaker has been introduced as a new circuit for quickly and automatically switching off in response to faults. A modified Z-source breaker design is introduced for the operation at medium-voltage dc with future applications in naval ship power systems. Compared to existing designs, the respective design will allow for greater control of step changes in load. This new design also limits capacitor current in the circuit and can be easily modified for fault detection. Analysis of the breaker operation is presented during both the fault and step changes in load. Low-voltage laboratory validation of the breaker was carried out on two different versions of the proposed circuit.
international symposium on power electronics, electrical drives, automation and motion | 2014
Atif Maqsood; Keith Corzine
The z-source breaker is a new kind of breaker which is designed specifically for dc power systems. Without a zero crossing, interrupted dc currents produce arcing and hence ac breakers would not be applicable. The z-source breaker resolves this problem because it is designed to turn off as soon as it experiences a sharp transient in current. In this paper a new design for the z-source breaker is considered so that load transients are not identified as faults. The design is also modified to accommodate bi-directionality which is required in mediumvoltage dc ship power systems. A higher-level coordinated control scheme is discussed which enables multiple breakers to coordinate and isolate the fault in a simple medium-voltage dc ship power system architecture with a central control unit.
clemson university power systems conference | 2014
Allan Overstreet; Atif Maqsood; Keith Corzine
The z-source breaker has been introduced as a new circuit for quickly and automatically switching off in response to faults. A modified z-source breaker design is introduced for operation at medium-voltage dc with future applications in naval ship power systems. Compared to existing designs the respective design will allow for step changes in load. This new design also limits capacitor current in the circuit and can be easily modified for fault detection. Analysis of the breaker operation is presented during both fault and step changes in load. Low voltage laboratory validation of the breaker was carried out on two different versions of the proposed circuit.
european conference on cognitive ergonomics | 2015
Atif Maqsood; Keith Corzine
This paper considers design details of the z-source breaker. Specifically, the effect of coupled inductors on the z-source breaker is studied. It is shown that the inductor weight can be reduced by 30% and the inductor volume can be reduced by about 25% when coupled inductors are used. Furthermore, the coupling plays a part in the commutation process meaning that the breaker can operate with one capacitor instead of two. These results mean that the major components of the z-source breaker can be greatly reduced. Simulations are carried out to verify the results.
IEEE Electrification Magazine | 2016
Atif Maqsood; Keith Corzine
Since the great debate between Thomas Edison and Nikola Tesla, our nations power system has operated on alternating current (ac). This was chosen over direct current (dc) because of the need to increase voltage with ac transformers to a high value using transformers for long-distance power transmission. The system has served its purpose well, but now, many energy sources, such as solar panels, fuel cells, and batteries, supply dc voltage. Also, dc/dc power converters are commonly used to transform voltage and to interface these dc sources with a larger system. Because of this, local dc power systems (or microgrids) have become popular topics in research literature. It also turns out that interfacing a wind power generator to a dc system is simpler than interfacing it to an ac system because ac/dc conversion is needed for the former and ac/dc/ac conversion is needed for the latter. Although energy sources and power conversion are readily available for dc power systems, some highperformance applications require fast-acting dc circuit breakers, which are currently in the experimental phase. This article discusses options for high-performance dc circuit breakers and specifically details the coupled-inductor dc breaker. This breaker is demonstrated for fault protection in a notional dc microgrid.
electric ship technologies symposium | 2015
Atif Maqsood; Keith Corzine
The Navy is considering alternative power system architectures to traditional 60 Hz Medium Voltage Alternating Current (MVAC) power systems for shipboard operation. One alternative architecture being strongly considered for several reasons, is Medium-Voltage Direct Current (MVDC). With that consideration, comes the need for effective electrical fault risk prevention and mitigation. This paper explores the application of the recently invented “z-source dc circuit breaker” to a ship power system. Specifically, detailed simulation is used to study the response of the z-source breaker to faults at various locations in a ring-type dc power system. The addition of a central control unit results in ideal response in that only breakers necessary to isolate the fault remain open for all cases. This paper further explores implementation issues for eventual application to Navy ships.
IEEE Journal of Emerging and Selected Topics in Power Electronics | 2017
Atif Maqsood; Keith Corzine
The next-generation electric ships will feature a medium-voltage dc architecture for distribution of electric power. For higher reliability and flexibility, this dc microgrid is divided into zones each zone having its own protection and load center. The research presented in this paper explores how Z-source dc breakers can be integrated into zonal-based distribution microgrids. Specifically, this paper looks into the practical problems and solutions for running two Z-source breakers in parallel to supply current to the same load center. It is shown that the basic structure of two breakers in parallel can be replicated over a system with multiple zones to protect the entire grid. This paper presents a detailed look into the gate control of the SCRs in Z-source dc breakers. The path of the fault current for shunt faults created at various locations is traced. Using that information, a fault detection algorithm is presented and applied. The measured currents collected during faults and steady state operation will determine the gate signals for the SCRs. The postfault operation might include reclosing of a Z-source breaker if deemed necessary by the control. The simulation and hardware results verify the concepts proposed in this paper.
clemson university power systems conference | 2016
Atif Maqsood; Lu Li; Keith Corzine
The need to develop a protection scheme has been one of the main focus points of recent research in dc grid technology. Z-source breakers are a relatively new invention in this field. Considerable research on the z-source breaker has been focused on its optimum design rather than control. In a single load / single source system these breakers do not need a complicated control. Recently a control scheme has been proposed for z-source breakers in an MVDC ring architecture with multiple loads and sources. This paper discusses design of a low-voltage dc system that can be used as a testbed for that z-source breaker protection scheme. For ease of implementation, the construction of this system has been broken down into three stages. During each stage a different aspect of the system and the breakers performance will be observed and tested. Also, a prototype enclosure for z-source breaker is designed and initial testing results are presented. The breaker box has been assembled in a very generic way so it can be installed into any test bed with similar power levels. The control scheme requires all the breakers to communicate with a central control. This paper discusses some processing and communication solutions for the small range lab environment and proposes a scheme for setting up that network.
arXiv: Optimization and Control | 2018
Atif Maqsood; Yu Zhang; Keith Corzine
IEEE Journal of Emerging and Selected Topics in Power Electronics | 2018
Vahid Dargahi; Mostafa Abarzadeh; Keith Corzine; Johan Enslin; Arash Khoshkbar Sadigh; Jose Rodriguez; Frede Blaabjerg; Atif Maqsood; Kamal Al-Haddad