J.A.A. Qahouq

University of Alabama, Tuscaloosa, Alabama, United States

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Publications (61)43.02 Total impact

  • [Show abstract] [Hide abstract]
    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.
    applied power electronics conference APEC; 03/2014
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    ABSTRACT: This paper presents an integrated power conditioning converter for photovoltaic application, where a maximum power point tracker (MPPT) is used in order to maximize the harvested power. Ripple correlation control technique is used to extract the maximum power from the cell. The power conditioning system (PCS) in this paper uses a single cell structure. The integrated converter incorporated in the PCS is based on the buck-boost topology to enhance the photovoltaic system performance especially in very low irradiation conditions. Simulation results using H-Spice are presented in this paper in order to verify the operation and its principle.
    Telecommunications Energy Conference (INTELEC), 2013 IEEE 35th International-Germany; 10/2013
  • Zhigang Dang, Jaber Abu Qahouq
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    ABSTRACT: Power inductor is one of the largest and most weighted components in power converters. On-chip power inductor with high saturation current and a relatively large inductance value is desired to be with a smaller size (footprint) [1-5]. Coupled power inductor (CPI) has many applications, and one of them is in multi-phase power converters [6-10]. One of the main advantages of the CPI used in DC-DC power converters is the ability to obtain smaller equivalent transient inductance (advantageous for lower output voltage dynamic deviation under transients) with a larger equivalent steady-state inductance (advantageous for smaller steady-state output voltage ripple and higher power efficiency). Inversely coupled power inductor was employed in the multi-phase switching power converters to improve both the steady-state and transient performances [8-10].
    Telecommunications Energy Conference 'Smart Power and Efficiency' (INTELEC), Proceedings of 2013 35th International; 01/2013
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    ABSTRACT: A PV solar system architecture with Multi-Input Single-Inductor power converter and Maximum Power Point Tracking (MPPT) control (MISI-MPPT) is presented in the paper. A multi-input single-inductor (MISI) power converter topology is used to interface multiple PV panels or cells with the load in the PV system. A digital controller is used to operate the MISI power converter in discontinuous conduction mode (DCM) and perform MPPT for each individual PV input. The result is reduced cost and size of the system while achieving high tracking efficiency. Simulation model is developed by using Matlab(r)/Simulink(r) software package and simulation results are obtained and presented in this paper.
    Telecommunications Energy Conference 'Smart Power and Efficiency' (INTELEC), Proceedings of 2013 35th International; 01/2013
  • Yuncong Jiang, J.A.A. Qahouq, T.A. Haskew
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    ABSTRACT: This paper presents a load-current-based maximum power point tracking (MPPT) digital controller with an adaptive-step-size and adaptive-perturbation-frequency algorithm. Only one sensor is needed in the controller circuitry since the MPPT controller is only utilizing the load current information. By utilizing a variable step-size algorithm, the speed, accuracy, and efficiency of the PV system MPPT are improved when compared to the fixed step-size load-current-based algorithm. Furthermore, the proposed adaptive algorithm utilizes a novel variable perturbation frequency scheme which further improves the controller speed. The concept and operation of the load-current adaptive-step-size and adaptive-perturbation-frequency MPPT controller are presented, analyzed, and verified by results obtained from a proof-of-concept experimental prototype.
    IEEE Transactions on Power Electronics 01/2013; 28(7):3195-3205. · 4.08 Impact Factor
  • Zhigang Dang, Jaber A. Abu Qahouq
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    ABSTRACT: This paper presents a power inductor with toroid core that utilizes a Permanent Magnet (PM) in its gap (PMTPI) in order to increase saturation current while keeping the same size and inductance. After discussing the PMTPI structure, the results of ANSYS®/Maxwell® physical model simulation results for a design example are presented. The design example considered in this paper is for a toroid-core power inductor with dimensions of 12.5mm × 12.5mm × 6.5mm and inductance of ∼592nH. The saturation current is increased from 14A in the conventional design to 28A in the proposed design.
    Applied Power Electronics Conference and Exposition (APEC), 2013 Twenty-Eighth Annual IEEE; 01/2013
  • J.A. Abu Qahouq, V. Arikatla
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    ABSTRACT: A switching power-converter closed-loop online autotuning controller is presented in this paper. The presented controller is based on tuning the closed-loop-compensator parameters by simply observing the compensated-error-signal time-domain characteristics. Moreover, the presented online autotuning controller does not require the knowledge of the power-stage frequency response, does not depend on any conventional rule-of-thumb control-design criteria such as gain and phase margins, can be used without interrupting the normal operation of the power converter, and is relatively simple when compared to other methods particularly those that require measuring the frequency response of the power stage or closed-loop converter system. The online autotuning controller is presented in this paper based on a dc-dc buck switching converter with a fully digital closed-loop controller, as an example and not for limitation.
    IEEE Transactions on Industrial Electronics 01/2013; 60(5):1747-1758. · 5.17 Impact Factor
  • Wangxin Huang, J.A. Abu Qahouq
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    ABSTRACT: This paper presents a scheme to manually tune a digital Proportional-Integral (PI) controller (TunePI scheme) to achieve optimized dynamic performance of a DC-DC power converter. Based on a previously proposed compensated-error-signal-based auto-tuning of compensator gain to achieve optimized gain for a given set of other compensator parameters, i.e. zero(s) and pole(s), the paper presents a new scheme that will tune the complete set of a PI compensator parameters to result in a design with an optimum set of parameters for improved dynamic performance. This paper focuses on discussing the TunePI scheme and presenting theoretical and experimental results that employ the TunePI scheme to manually tune a digital PI compensator. This will be used as the base for a future work to develop a controller that is able to auto-tune the PI compensator during the power converter operation (online auto-tuning).
    Applied Power Electronics Conference and Exposition (APEC), 2013 Twenty-Eighth Annual IEEE; 01/2013
  • Wangxin Huang, J.A.A. Qahouq
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    ABSTRACT: A modified control scheme is presented in this paper to improve the load transient response of DC-DC power converter by utilizing a previously proposed auxiliary circuit which is capable of operating in both boost mode to discharge the output capacitor during load step down transient, and in buck mode to charge the output capacitor during load step up transient. The proposed modified control scheme for the auxiliary circuit is based on the output voltage peak detection, preset thresholds and zero crossing time information. This scheme achieves significant improvement in load transient response while eliminating the controller performance sensitivity to component values tolerances and complex calculations that could result in undesired transient response. A simulation model is built in MATLAB®/SIMULINK® software package to validate the functionalities and advantages of the proposed control scheme.
    Telecommunications Energy Conference (INTELEC), 2012 IEEE 34th International; 01/2012
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    ABSTRACT: Analog maximum power point tracking (MPPT) controller circuit for photovoltaic solar panels/cells is an attractive solution due to its low cost and simple implementation. The paper presents an analog Maximum Power Point Tracking (MPPT) controller for a Photovoltaic (PV) solar system that utilizes the load current to achieve maximum output power from the solar panel. Compared to the existing MPPT controller circuitry which requires multiplication of the sensed PV panel voltage and current to yield panel power, the cost and size of the proposed circuit are reduced. The tracking performance of the proposed MPPT controller is validated by simulation results. The proposed MPPT controller circuit can be further implemented by CMOS technology and fabricated on-chip to perform distributed maximum power point tracking (DMPPT) in PV system.
    01/2012;
  • V.P. Arikatla, J.A. Abu Qahouq
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    ABSTRACT: An adaptive digital proportional-integral-derivative (AD-PID) controller scheme is presented in this study to improve the dynamic performance of power converters. The controller adaptively adjusts the integral constant (Ki) and the proportional constant (Kp) following a new control law. The control law is a function of the magnitude change in the error signal and its peak value during dynamic transients. The proposed AD-PID controller adaptively detects the peak value of the error signal, which is a function of the transient nature and magnitude and utilises it in the control law such that no oscillations are generated as a result of the adaptive operation. As a result, the dynamic output voltage deviation and the settling time of the output voltage are reduced. The concept and architecture of the proposed AD-PID are presented and its proposed control law is discussed and verified by experimental results obtained from a single-phase DC-DC buck converter with input voltage range of 8-10-V, nominal output voltage of 1.5-V and a maximum load current of 7-A.
    IET Power Electronics 01/2012; 5(3):341-348. · 1.52 Impact Factor
  • J.A. Abu Qahouq, D.L. Carnahan
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    ABSTRACT: Carbon nanotubes (CNTs) with their different types have several potential future applications, including on-chip integrated electronic devices. The growth control of CNTs in the desired shape is important to realise such devices. A method to control the growth of CNTs in a desired spiral shape or other similar shapes on silicon (Si) substrates is proposed. Multi-walled carbon nanotube growth in a circular spiral shape is demonstrated by using a trenched-patterned-shape on the Si substrate method. The growth concept, the growth and fabrication steps, and the growth and fabrication results are presented.
    Electronics Letters 01/2012; 48(11):639-641. · 1.04 Impact Factor
  • Yuncong Jiang, J.A.A. Qahouq, M. Orabi
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    ABSTRACT: Mismatching effects are major drawbacks existing in today's photovoltaic (PV) solar systems. To improve power system stability and energy conversion efficiency, distributed maximum power point tracking (DMPPT) techniques are developed. In this paper, single-stage DMPPT power management DC-AC inverter architecture (SS-AC-DMPPT) is presented and verified by Matlab®/Simulink® simulation model results. In the SS-AC-DMPPT PV solar system architecture, multiple inverters are connected in series in order to yield higher AC output voltage to the load such as the grid, each inverter is directly connected to a PV solar panel or cell, and MPPT control is performed by each inverter.
    Telecommunications Energy Conference (INTELEC), 2012 IEEE 34th International; 01/2012
  • Yuncong Jiang, Jaber A. Abu Qahouq
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    ABSTRACT: Maximum power point tracking (MPPT) techniques are used in photovoltaic system to maximize solar array output power under varying conditions. This paper presents simulation and experiment prototype results of a standalone PV system with multiple solar panels or cells and with different perturbation step sizes, including the realization of MPPT algorithm and power stage control. The controller tracks MPP of each individual panel/cell by sensing only the output currents in the PV system. The effect of the perturbation step size value on controller speed and accuracy is experimentally tested analyzed.
    01/2012;
  • Y. Jiang, J.A. Abu Qahouq
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    ABSTRACT: This study presents a maximum power point tracking (MPPT) method and controller for a multi-channel (N-channel) photovoltaic solar system. The N-channel single-sensor MPPT (SS-MPPT) controller is able to track the maximum power point (MPP) of each solar panel using only one output current sensor in the N-channels. Compared with a conventional N-channel MPPT system which requires N voltage sensors, N current sensors, 2N analogue-to-digital converters (ADCs) (or an ADC with 2N channels) and N-MPPT controllers along with the associated conditioning circuitries, the proposed method only requires one sensor, one ADC and one MPPT controller. In the proposed N-channel SS-MPPT controller, the MPPT for each channel is achieved by tracking the maxima of the output (load) current (resulting in the maxima of the system output power) using the Perturb and Observe algorithm and the maxima of each channel power via channel output current difference optimisation. Two algorithms which can be used to realise the SS-MPPT controller are discussed and compared. The concept and operation of the SS-MPPT controller is presented, analysed and verified by results obtained from a proof-of-concept experimental prototype.
    IET Power Electronics 01/2012; 5(8):1581-1592. · 1.52 Impact Factor
  • O. Mousa, J.A.A. Qahouq
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    ABSTRACT: This paper reviews ANSYS®/Maxwell® modeling and design results of a nanotechnology-based integrated power inductor. The on-chip integrated power inductor utilizes Carbon Nanotubes Bundled Multi-walled (Concentric) Carbon Nanotubes (BMWCNT) and Fe (iron) in order to achieve high performance in a small size.
    Applied Power Electronics Conference and Exposition (APEC), 2012 Twenty-Seventh Annual IEEE; 01/2012
  • W. Huang, J.A. Abu Qahouq, S. Ahmed
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    ABSTRACT: Adaptive voltage positioning (AVP) has been used in DC-DC switching power converters for powering integrated circuits due to its advantages of utilizing allowable output voltage tolerance while decreasing the output filter capacitance requirement, and achieving faster transient response. Most of the AVP control schemes in the published literature require current sensing and sampling circuits which increase cost, size, complexity and can cause inaccuracies of AVP operation. A SLAVP controller of DC-DC buck converter is recently proposed in the literature which can achieve AVP control based on the linear relationship between the output current value and the duty cycle value while using the duty cycle value as an indicator of current value. However, this SLAVP control scheme cannot be directly applied to DC-DC boost converter topology because of two reasons. One is the RHP (Right Half Plane) zero of boost converter which might yield system stability issues and ringing effects during light to heavy load transients. Second, the relationship between the output current value and the duty cycle value of the DC-DC boost converter is nonlinear. This paper proposes a linearized sensorless AVP (L-SLAVP) control scheme which successfully addresses the second issue. The theoretical basis of the proposed scheme is given and a simulation model of boost converter with L-SLAVP controller is developed in MATLAB®/SIMULINK® environment for verification and evaluation.
    Energy Conversion Congress and Exposition (ECCE), 2012 IEEE; 01/2012
  • Yuncong Jiang, J.A. Abu Qahouq
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    ABSTRACT: Because the power from Photovoltaic (PV) solar arrays depends on the array operating and surrounding conditions, it is beneficial to implement a maximum power point tracking (MPPT) technique to enlarge the amount of output power. There are several MPPT concepts and algorithms presented in the literature. This paper evaluates a load/output current based MPPT (LOC-MPPT) technique using P&O algorithm which requires the load current sensing only as the control variable. The LOC-MPPT technique is experimentally evaluated in this paper with different perturbation step sizes using a PV solar system prototype. The effect of the perturbation step size value on controller speed and accuracy is experimentally analyzed.
    Energy Conversion Congress and Exposition (ECCE), 2011 IEEE; 10/2011
  • J.A.A. Qahouq, V. Arikatla
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    ABSTRACT: A digital sensorless adaptive voltage positioning (SLAVP) control method is presented in this paper in order to realize AVP control without the need for load or inductor current sensing and high-resolution high-speed analog-to-digital converter sampling. The SLAVP control law utilizes the readily available error signal of the conventional voltage-mode closed-loop compensated controller or, in other words, the duty cycle of a dc-dc buck converter in order to realize AVP control. The elimination of the need for high-speed and accurate sensing and sampling of currents using the proposed SLAVP control reduces the size and cost of the digital controller, reduces the power losses associated with current sensing and sampling, and simplifies hardware design. Moreover, the SLAVP control can easily be added to controllers with conventional voltage-mode closed-loop control with minimum size and cost increase, and therefore, SLAVP control can be used for a wide range of applications and not only for high-end applications like powering microprocessors. The theoretical SLAVP control law derivation and analysis and SLAVP controller architecture are presented in this paper and verified by experimental results obtained from a proof-of-concept experimental prototype.
    IEEE Transactions on Industrial Electronics 10/2011; · 5.17 Impact Factor
  • O.F. Mousa, J.A. Abu Qahouq
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    ABSTRACT: This paper presents a nanotechnology-based high power-density and low-power-loss on-chip power inductor for dc-dc switching power converters. This power inductor utilizes a composite of bundled multiwalled (concentric) carbon nanotubes (BMWCNTs) and Fe (iron) in order to achieve high performance in a small size. Titanium (Ti) is then added as a coating material on the BMWCNT-based power inductor. The BMWCNT-based power inductor with a single layer and three turns occupies an area of 200 μm × 200 μm. It exhibits an inductance of 206 nH, a quality factor of 427 at 20 MHz, and a dc rated current of 100 mA. The power inductor size and the performance characteristics are competitive with state-of-the-art power inductors. The design, analysis, modeling, and simulation results of the BMWCNT-based power inductor are presented and compared with state-of-the-art conventional power inductors from the literature.
    IEEE Transactions on Electron Devices 09/2011; · 2.06 Impact Factor

Publication Stats

221 Citations
43.02 Total Impact Points

Institutions

  • 2007–2013
    • University of Alabama
      • Department of Electrical and Computer Engineering
      Tuscaloosa, Alabama, United States
    • Intel
      Santa Clara, California, United States
  • 2001–2006
    • University of Central Florida
      • • Department of Electrical Engineering & Computer Science
      • • College of Engineering & Computer Science
      Orlando, FL, United States