Jaber A. Abu Qahouq

University of Alabama, Tuscaloosa, Alabama, United States

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Publications (89)88.33 Total impact

  • Zhigang Dang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents an experimental evaluation of a high current toroid power inductor (TPI) with NdFeB permanent magnet (PMTPI). By adding a small piece of fabricated NdFeB-N35EH magnet (magnet volume is ~0.36% of the PMTPI ferrite core volume) in the air gap of the TPI, the saturation current of the PMTPI is doubled with the same size and inductance value. The desired dimensions of the NdFeBN35EH PM are calculated before fabrication and then the fabricated PM is characterized. The ~6.8 μH PMTPI is tested in a 5V to 2V buck power converter. Results show that compared to a TPI with the same size and inductance (~6.8μH) without the PM, the saturation current of the PMTPI is doubled (from 7A to 14A). Compared to another TPI with a larger size needed to double the saturation current, the ferrite core weight of the PMTPI is reduced to 53.6% and the core volume is reduced to 59.2%. Experimental results also show that the addition of the NdFeB-N35EH PM does not introduce additional power losses and increase of temperature for the PMTPI and does not affect the power converter efficiency.
    No preview · Article · Nov 2015 · IEEE Transactions on Industrial Electronics
  • Zhigang Dang · Yuan Cao · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents a method for a reconfigurable magnetic resonance-coupled wireless power transfer (R-MRC-WPT) system in order to achieve higher transmission efficiency under various transmission distance and/or misalignment conditions. Higher efficiency, longer transmission distance, and larger misalignment tolerance can be achieved with the presented R-MRC-WPT system when compared to the conventional four-coil MRC-WPT (C-MRC-WPT) system. The reconfigurability in the R-MRC-WPT system is achieved by adaptively switching between different sizes of drive loops and load loops. All drive loops are in the same plane and all load loops are also in the same plane; this method does not require mechanical movements of the drive loop and load loop and does not result in the system volume increase. Theoretical basis of the method for the R-MRC-WPT system is derived based on a circuit model and an analytical model. Results from a proof-of-concept experimental prototype, with transmitter and receiver coil diameter of 60 cm each, show that the transmission efficiency of the R-MRC-WPT system is higher than the transmission efficiency of the C-MRC-WPT system and the capacitor tuning system for all distances up to 200 cm (~3.3 times the coil diameter) and for all lateral misalignment values within 60 cm (one coil diameter).
    No preview · Article · Nov 2015 · IEEE Transactions on Power Electronics
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    ABSTRACT: An on chip integrated power management circuit with maximum power point tracking (PM-MPPT) control is proposed in this paper in order to achieve high efficiency Photovoltaic (PV) system. The proposed PM-MMPT circuit mitigates partial shading issues which exist in PV systems by utilizing cell-level distributed MPPT architecture, where each cell has its own MPPT circuit, in order for each cell to produce its own maximum power without affecting other cells or being affected by other cells. The proposed PM-MPPT circuit consists of two different parts. The first part is a high-efficiency synchronous power converter stage. The second part is an analog ripple correlation control (RCC) MPPT control circuit which provides faster and efficient MPP tracking, has less circuit complexity and low power consumption. HSPICE simulation model of the proposed PM-MPPT circuit is developed with a solar cell that has 0.5 V open circuit voltage and 6 A short circuit current. Simulation results show that the proposed PM-MPPT circuit rapidly tracks the MPP with a tracking efficiency larger than 99% over a wide range of irradiation levels and 92% system power conversion efficiency at a 2 W power level. The detailed analog design of the power stage and the RCC MPPT circuits are presented and discussed in the paper based on 0.35 μm CMOS technology. In addition, the PM-MMPT IC layout is presented and discussed. To validate the proposed technique and design, a comparison between the results of the proposed circuit and other reported techniques from the literature is provided. It is shown that the proposed circuit and system are able to operate with the lowest input voltage and the highest output power compared with other reported techniques. Moreover, the proposed design has the smallest size under 2 W power level.
    No preview · Article · Jul 2015 · Solar Energy
  • Z. Dang · J.A. Abu Qahouq
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    ABSTRACT: This paper first identifies the Transmission Efficiency Valley of Death (TEVD) in laterally misaligned magnetic resonance coupled (MRC) wireless power transfer (WPT) system. The paper then presents a method to eliminate the TEVD by angularly rotating the transmitter coil (Tx) or receiver coil (Rx). Simulation results of the ANSYS® HFSS® 3-D physical model with 5-turn spiral shape four-coil MRC-WPT system with 60cm outer diameter show that when the Rx is 30cm vertically away from the Tx, TEVD exists when the lateral misalignment value (MIS) ranges from 50cm to 70cm. The presented method eliminates the TEVD and extends the high efficiency range from MIS = 50 cm (83.3% of the Rx diameter) to MIS = 70 cm (117% of the Rx diameter).
    No preview · Article · May 2015
  • W. Huang · J.A. Abu Qahouq · Z. Dang · C. Johnson
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    ABSTRACT: Single-inductor multiple-output (SIMO) switching DC-DC power converter architecture is a cost-effective alternative to multiple individual switching power converters solution in many power distribution system applications where multiple voltage rails are required. However, with multiple output voltage rails coupled to the same switching node, the SIMO power converters suffer from cross regulation among the multiple outputs, which complicates the closed-loop controller design of the SIMO converter and degrades performance. In this paper, an inductor continues conduction mode (DCM) power-multiplexed control (PM-DCM control) scheme is proposed aiming to completely decouple the multiple outputs from one another. The proposed PM-DCM control scheme results in eliminating the cross regulation among the multiple outputs while maintaining desired voltage regulation performance for each output under both steady-state and dynamic operations. Moreover, low-cost microcontroller or analog circuitries can be used to implement the proposed controller. Simulation and preliminary experimental results are given to verify the feasibility and advantages of the proposed concept.
    No preview · Article · May 2015
  • Z. Dang · J.A. Abu Qahouq
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    ABSTRACT: Two-coil and four-coil magnetic resonance coupled wireless power transfer (MRC-WPT) system configurations are analyzed and compared in this paper based on the simplified circuit model and 3-D physical model simulations. Physical model simulation results of symmetrical MRC-WPT systems show that when the sizes of transmitter (Tx) coil and receiver (Rx) coil are equal and without any external capacitors, the four-coil system achieves longer transmission distance and larger misalignment tolerance with relatively lower efficiency at close distance compared to the two-coil system. The designed 10-turn, 400mm outer diameter spiral shape four-coil WPT system achieves operation distance of 500mm with nearly constant maximum transmission efficiency of 85%, while the two-coil system achieves ∼96% of efficiency up to distance of 350mm. When the vertical Tx to Rx distance is fixed at 150mm, the four-coil system has a larger lateral misalignment tolerance of 275mm compared to the two-coil system which has misalignment tolerance of 200mm at the same distance.
    No preview · Article · May 2015
  • Zhigang Dang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents a 14mm×7mm×5mm EE core ∼760nH power inductor (PI) with a permanent magnet (EE-PMPI). By using a small piece of the NdFeB magnet, the saturation current of the EE-PMPI is doubled while maintaining the same footprint size and the same inductance value. 3-D physical model simulation results obtained from the ANSYS®/Maxwell® are used to illustrate and visualize the saturation current doubling of the EE-PMPI. Results show that compared to a conventional PI with the same size and almost the same inductance (∼730nH), the saturation current of the EE-PMPI is increased from 15A to 30A.
    No preview · Article · May 2015
  • Z. Dang · J.A. Abu Qahouq
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    ABSTRACT: This paper presents an on-chip three-phase coupled power inductor (3-CPI) structure which consists of a layer of ferrite core material and another layer of three phase coupled spiral windings on a silicon substrate. The flux cancellation effect of the inversely coupled windings significantly reduces the net flux in the ferrite layer, which helps increasing the saturation current of the power inductor. An ANSYS®/Maxwell® 3-D physical model of an 8mm×7.6mm 3-CPI design is developed and simulation results are obtained. Simulation results show that the saturation current (12A/phase) of the 3-CPI is twice the saturation current (6A) of the non-coupled power inductor with the same inductance density. Based on a 5V/1.5V 5MHz three-phase buck converter design, the equivalent steady-state inductance and transient inductance of the 3-CPI design are calculated to be equal to 33.8nH and 7.2nH, respectively.
    No preview · Article · May 2015
  • W. Huang · J.A.A. Qahouq
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    ABSTRACT: Current sharing is commonly used in multiphase converters in order to ensure equal current distribution between converter phases. Conventional current sharing control schemes typically require sensing the phases' currents, which results in increased complexity, size and cost in addition to issues associated with sensing inaccuracies. In this paper, a sensorless current sharing control scheme is proposed in order to achieve equal current sharing among the phases without the need for current sensing and calibration circuitries. The proposed controller achieves equal current sharing based on auto-tuning the phases' duty cycle values to minimize the differences between the input voltage ripple values within a switching cycle of each phase. Simulation results obtained from a two-phase synchronous buck converter are presented to verify the operation and advantages of the proposed concept.
    No preview · Article · May 2015
  • Z. Dang · J.A. Abu Qahouq
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    ABSTRACT: This paper presents a two-coil reconfigurable wireless power transfer (WPT) system topology in order to optimize transmission efficiency under different transmission distance (DIS) and lateral misalignment (MIS) conditions. The reconfigurable WPT system includes one transmitter (Tx) side and one receiver (Rx) side but it could switch between different circuit configurations (which are made up of different values of series and shunt capacitors) at Tx side and/or Rx side. Design guidelines of the two-coil reconfigurable WPT system are devised based on an equivalent circuit model. A proof of concept prototype with three different adaptive configurations at Tx side and one configuration at Rx side is built and experimentally compared with conventional two-coil WPT system. Results show that when the system is perfectly aligned, the reconfigurable system improves the transmission efficiency by up to 20%. When system is laterally misaligned, the transmission efficiency is improved by up to 19%.
    No preview · Article · May 2015
  • Wangxin Huang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents an energy sharing state-of-charge (SOC) balancing control scheme based on a distributed battery energy storage system architecture where the cell balancing system and the dc bus voltage regulation system are combined into a single system. The battery cells are decoupled from one another by connecting each cell with a small lower power dc-dc power converter. The small power converters are utilized to achieve both SOC balancing between the battery cells and dc bus voltage regulation at the same time. The battery cells' SOC imbalance issue is addressed from the root by using the energy sharing concept to automatically adjust the discharge/charge rate of each cell while maintaining a regulated dc bus voltage. Consequently, there is no need to transfer the excess energy between the cells for SOC balancing. The theoretical basis and experimental prototype results are provided to illustrate and validate the proposed energy sharing controller.
    No preview · Article · May 2015 · IEEE Transactions on Industrial Electronics
  • Jaber A. Abu Qahouq · Yuncong Jiang · Mohamed Orabi
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    ABSTRACT: Photovoltaic (PV) solar systems with series-connected module integrated converters (MICs) are receiving increased attention because of their ability to create high output voltage while performing local maximum power point tracking (MPPT) control for individual solar panels, which is a solution for partial shading effects in PV systems at panel level. To eliminate the partial shading effects in PV system more effectively, sub-MICs are utilized at the cell level or grouped cell level within a PV solar panel. This study presents the results of a series-output-connection MPPT (SOC-MPPT) controller for sub-MIC architecture using a single sensor at the output and a single digital MPPT controller (sub-MIC SOC-MPPT controller and architecture). The sub-MIC SOC-MPPT controller and architecture are investigated based on boost type sub-MICs. Experimental results under steady-state and transient conditions are presented to verify the performance of the controller and the effectiveness of the architecture.
    No preview · Article · Nov 2014 · Journal of power electronics
  • Wangxin Huang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents a simple online impedance measurement method for electrochemical batteries, including lithium-ion, lead-acid, and nickel–metal-hydride chemistries. By using the proposed online impedance measurement method, there is no need to disconnect the battery from the system or to interrupt system operation, and there is no need to add ac signal injection circuits, costly response measurement, and analysis circuits/devices. In practical battery-powered systems, a power converter is usually used to interface the battery with the load for voltage/current regulation purposes. In this paper, through the control of the power converter and duty-cycle perturbation, the ac impedance of the battery can be determined. The proposed method provides a low-cost and practical solution for the online measurement of the ac impedance of batteries. Moreover, the proposed method can be either continuously or periodically performed without interrupting the normal operation of the battery system and the power converter. In addition, this paper provides an example where the obtained impedance data are utilized for online state-of-charge estimation of lithium-ion batteries. The proposed online impedance measurement method is validated by experiments conducted on a 2.6-Ah 18650-size lithium-ion battery interfaced to the load via a bidirectional dc–dc boost/buck converter.
    No preview · Article · Nov 2014 · IEEE Transactions on Industrial Electronics
  • Jaber A. Abu Qahouq · Yuncong Jiang
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    ABSTRACT: This study presents a distributed photovoltaic (PV) solar system architecture with a single-power inductor, singlepower converter and single maximum power point tracking (MPPT) controller that only requires one sensor. This PV architecture is able to perform MPPT for a multichannel distributed PV system at panel level, cell group level and/or single cell level under mismatching and partial shading conditions. The single power stage is a multiple-input single-inductor boost power converter which operates in continuous conduction mode. This work targets the high-cost and high-complexity issues of module integrated converter (MIC) and sub-MIC PV architectures, which affect their practicality in many applications. The concept and operation of the single-power-converter single-controller single-sensor MPPT architecture is presented, analysed and verified by results obtained from a proof-of-concept experimental prototype.
    No preview · Article · Oct 2014 · IET Power Electronics
  • Ahmed shawky Aqle · Mohamed Orabi · Jaber Abu Qahouq · Mohamed Youssef
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    ABSTRACT: Abstract-this paper introduces a full comparative evaluation of the advanced PV architectures especially for energy harvest application. The comparative evaluation involves module architecture, sub-module architecture, and cell architecture. The comparison includes the capability of theses PV architectures to mitigate the effect of the mismatch loss that inherently comes from different irradiation on the PV system. Then, the effect of the bypass diodes on the PV performance under these three architectures is also considered.
    No preview · Conference Paper · Sep 2014
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    ABSTRACT: This paper presents the design of an on-chip integrated power management architecture with Maximum Power Point Tracking (MPPT) for Photovoltaic (PV) solar system. The system is developed in order to extract higher power for PV system under partial shading and other mismatching conditions. The MPPT circuit is implemented in 0.35μm Complementary Metal–Oxide–Semiconductor (CMOS) technology. The on-chip system utilizes a high-efficiency synchronous DC-DC boost power converter and analog Ripple Correlation Control (RCC) circuit for MPPT control. The 2400μm×5000μm developed Integrated Circuit (IC) is connected to a solar cell with 0.5V nominal output voltage and 5A output current. A peak efficiency of 92% is achieved. The design of the power stage and analog RCC MPPT algorithm circuit are presented and examined in this paper.
    No preview · Conference Paper · Mar 2014
  • Eman Goma · Mohamed Orabi · E.-S. Hasaneen · Jaber Abu Qahouq
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    ABSTRACT: This paper presents the design and HSPICE simulation results of an on-chip integrated Single-OutputSensor Maximum Power Point Tracking (SOS MPPT) PV solar system architecture. The cell-level on-chip integrated analog SOS MPPT circuit is designed to track the maximum power point of PV system under different conditions including changes in irradiation levels. The MPPT circuit is implemented using 0.35μm CMOS technology. Results are presented for a two PV solar cells connected in series and exposed to different solar irradiation levels, which show the ability of each cell to extract its MPP. The proposed cell-level integrated system is a step forward to overcome the effects of mismatches and/or partial shading phenomena in PV solar systems which affects efficiency. In addition, the system cost is reduced as a result of using one MPPT controller with only one sensor for N-cell PV solar system with cell-level MPPT control.
    No preview · Conference Paper · Mar 2014
  • Zhigang Dang · Jaber A. Abu Qahouq
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    ABSTRACT: Lateral misalignment between the transmitter (Tx) and receiver (Rx) in a wireless power transfer (WPT) system significantly reduces its power transmission efficiency. This paper first investigates the lateral misalignment in the magnetic resonance coupled (MRC) WPT system and identifies the High Efficiency Range (HER). The HER is a high efficiency area on the transmission efficiency versus Rx lateral misalignment amount curve. In the HER, the transmission efficiency is nearly constant at a maximum value before it sharply drops down to zero (or a very small value). The identification of the HER is verified by simulation results obtained from a developed ANSYS® HFSS® 3-D physical model. Simulation results of the ANSYS® HFSS® 3-D physical model with 5-turn, 60cm outer diameter spiral shape MRC-WPT system show that when the vertical distance (DIS) between the Tx and Rx ranges from 0.1 m to 1 m, an HER exists at each DIS value. When 0.3m ≤ DIS ≤ 0.6m, nearly constant high efficiency of ~90% could be maintained when the lateral misalignment is not larger than 50cm (83.3% of the Rx diameter).
    No preview · Conference Paper · Mar 2014
  • Wangxin Huang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents an online multivariable auto-tuning digital controller for DC-DC switching power converters. In the proposed scheme, all the variables/parameters (i.e. gain, zero(s) and pole(s)) of a digital PID compensator are auto-tuned simultaneously during system operation in order to achieve an optimized compensator that results in improved dynamic performance for a given power converter design. The proposed multivariable auto-tuning scheme is based on observing the time-domain characteristics of the compensated error signal, namely the output of the compensator, and it does not require the accurate knowledge of the power stage parameters and/or the measurement of the control loop frequency response. Experimental results are presented in order to illustrate and verify the multivariable auto-tuning scheme.
    No preview · Conference Paper · Mar 2014
  • Wangxin Huang · Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents a distributed battery energy storage architecture where the cells in the battery pack are decoupled from each other by connecting each cell with a lower power (smaller) DC-DC power converter. In addition to providing voltage regulation for the DC bus, these small DC-DC power converters are utilized to achieve state of charge (SOC) balancing among the cells by employing a proposed charge balancing controller that is based on energy sharing concept. As a result, no additional charge balancing circuits and controllers are needed in order to transfer charges between the cells of the battery pack. A system simulation model based on the proposed energy storage system architecture is developed in Matlab®/Simulink® in order to verify the feasibility and functionality of the proposed charge balancing controller.
    No preview · Conference Paper · Mar 2014

Publication Stats

610 Citations
88.33 Total Impact Points

Institutions

  • 2008-2015
    • University of Alabama
      • Department of Electrical and Computer Engineering
      Tuscaloosa, Alabama, United States
  • 2010
    • South Valley University
      • Faculty of Engineering
      Al Uqşur, Luxor, Egypt
  • 2001-2006
    • University of Central Florida
      • Department of Electrical Engineering & Computer Science
      Orlando, Florida, United States