The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
John L. Doane - One of the best experts on this subject based on the ideXlab platform.
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Compact HE_11 to surface wave converters for high power waveguide Dummy Loads
International Journal of Infrared and Millimeter Waves, 1993Co-Authors: John L. DoaneAbstract:The HE_11 mode in corrugated circular waveguide can be converted to the EH_11 mode (surface wave) by a short, smooth-waveguide phase shift section followed by a short corrugation depth taper. Low-power measurements at 110 GHz in 1.25 in. aluminum waveguide demonstrated approximately 99% conversion with the proper phase shift length. As expected, the conversion efficiency versus length of the phase shifter varied periodically with the period of the TE_11 to TM_11 beat wavelength. Since the EH_11 surface wave is highly attenuated, this type of converter can be used effectively in a compact high-power Dummy Load.
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Compact HE11 to surface wave converters for high power waveguide Dummy Loads
International Journal of Infrared and Millimeter Waves, 1993Co-Authors: John L. DoaneAbstract:The HE11 mode in corrugated circular waveguide can be converted to the EH11 mode (surface wave) by a short, smooth-waveguide phase shift section followed by a short corrugation depth taper. Low-power measurements at 110 GHz in 1.25 in. aluminum waveguide demonstrated approximately 99% conversion with the proper phase shift length. As expected, the conversion efficiency versus length of the phase shifter varied periodically with the period of the TE11 to TM11 beat wavelength. Since the EH11 surface wave is highly attenuated, this type of converter can be used effectively in a compact high-power Dummy Load.
Rajan Babu - One of the best experts on this subject based on the ideXlab platform.
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Regulated high-voltage power supply (RHVPS): Integration, operation, and test results with LHCD system of SST-1
IEEE Transactions on Plasma Science, 2014Co-Authors: Paresh Patel, Promod Kumar Sharma, Shefali Dalakoti, C. B. Sumod, Laxmi N. Gupta, Vishnu B. Patel, Vijay Vadher, K. K. Ambulkar, Dipal Thakkar, Rajan BabuAbstract:A regulated high-voltage power supply (RHVPS) and its results are\npresented for its initial integration and operation with lower hybrid\ncurrent drive (LHCD) system. Experimental results are shown to show the\nability of RHVPS as a practical source of electrical power for LHCD.\nKlystron is operated at 3.7 GHz. with a continuous wave RF power level\nof 500 kW with various subsystems. RHVPS has proven its capability for\nfeeding power to klystron with a safe and good level of required\nquality. Up to 65 kV and a Load current in excess of 18 A was imparted\nto klystron with a trapezoidal pulse of voltage. Repeatability of\noperation is shown by successive shot results. RHVPS is explained with\nits scheme and control system. Basic parameters are fulfilled with a\nDummy Load testing of RHVPS. Test results are illustrated for basic\nparameters with resistive Dummy Load. LHCD system operation parameters\nand experimental parameters of RHVPS for its operation are discussed. A\nregulation on flat top level of voltage is as per the requirement of\nLHCD system. Initial integration of RHVPS has been successful and future\nplans are mentioned for full-fledged SST-1 operation.
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High-Power Test of Chemical Vapor Deposited Diamond Window for an ECRH System in SST-1
IEEE Transactions on Plasma Science, 2013Co-Authors: B. K. Shukla, Rajan Babu, M. Kushwah, K. Sathyanarayana, Jatin Patel, Harshida Patel, S Belsare, Pragnesh Dhorajiya, Vipal RathodAbstract:High-power tests on chemical vapor deposited (CVD) diamond window are carried out using 82.6-GHz Gyrotron. To test CVD diamond window with calorimetric Dummy Load, a matching optic unit is designed and fabricated with special profiled mirrors. The mirrors are fabricated by Gycom Russia and a mirror box assembly is fabricated at Institute for Plasma Research. The mirrors and mirror box are cooled with water. The mirror box consists of four arc detectors for the protection of window. The CVD diamond window is connected to a Dummy Load with this mirror box. The alignment of mirror is done during the testing of CVD window in pulsed condition. After achieving the desired Gaussian pattern at the exit of mirror box, system is connected to a Dummy Load for continuous wave test. The CVD window is tested maximum power up to 60 kW in pulse duration of 600 s.
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High power test of CVD diamond window for ECRH system in SST-1
2011 IEEE NPSS 24th Symposium on Fusion Engineering, 2011Co-Authors: B. K. Shukla, Rajan Babu, M. Kushwah, K. Sathyanarayana, Jatin Patel, S. V. L. S. Rao, D. Pragnesh, Harshida Patel, S Belsare, R. VipalAbstract:High power tests on CVD diamond window are carried out using 82.6GHz Gyrotron. In order to test CVD diamond window with calorimetric Dummy Load, a matching optic unit is designed and fabricated with special profiled mirrors. The mirrors are fabricated by M/s. Gycom Russia and a mirror box assembly is fabricated at IPR. The mirrors and mirror box are cooled with water. The mirror box consists of four arc detectors for the protection of window. The CVD diamond window is connected to Dummy Load with this mirror box. The alignment of mirror is done during the testing of CVD window in pulsed condition. After achieving the desired Gaussian pattern at the exit of mirror box, system is connected to Dummy Load for CW test. The CVD window is tested up to 60kW power for 10minutes.
Y. T. Chang - One of the best experts on this subject based on the ideXlab platform.
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Study of the two-phase Dummy Load shut-down strategy for proton exchange membrane fuel cells
Journal of Power Sources, 2017Co-Authors: Qingjie Zhang, S. X. Xia, Zhisheng Yang, X Cui, R. Lin, Y. T. ChangAbstract:This paper presents a new system strategy designed to alleviate the performance decay caused by start-up/shut-down (SU/SD) conditions in proton exchange membrane fuel cells (PEMFCs). The innovative method was tested using a two-phase Dummy Load composed of a linearly declined main Load and a fixed small auxiliary Load. The initial value of the main Load must be controlled within a proper range, and a closed-ended air exhaust is necessary. According to the analysis of in-situ current density distribution during SD processes, the two-phase Dummy Load can continuously fit the process of oxygen reduction in the cathode, whereas the conventional Dummy Load leads to local air starvation. Polarization curves and cyclic voltammetry (CV) were employed to evaluate the performance decay during SU/SD repetition. After tests of 900 cycles, the highest voltage degradation rate of the PEMFC was 3.33 μV cycle−1(800 mA cm−2), and the electrochemical surface area (ECSA) loss was 0.0046 m2g−1cycle−1with the two-phase Dummy Load strategy. After comparing results with similar work on a single PEMFC, the authors confirmed the preeminent effectiveness of this strategy. This strategy will also improve fuel cell stack performance due to controllable SD duration and comparatively low performance decay rates.
K. K. Ambulkar - One of the best experts on this subject based on the ideXlab platform.
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Regulated high-voltage power supply (RHVPS): Integration, operation, and test results with LHCD system of SST-1
IEEE Transactions on Plasma Science, 2014Co-Authors: Paresh Patel, Promod Kumar Sharma, Shefali Dalakoti, C. B. Sumod, Laxmi N. Gupta, Vishnu B. Patel, Vijay Vadher, K. K. Ambulkar, Dipal Thakkar, Rajan BabuAbstract:A regulated high-voltage power supply (RHVPS) and its results are\npresented for its initial integration and operation with lower hybrid\ncurrent drive (LHCD) system. Experimental results are shown to show the\nability of RHVPS as a practical source of electrical power for LHCD.\nKlystron is operated at 3.7 GHz. with a continuous wave RF power level\nof 500 kW with various subsystems. RHVPS has proven its capability for\nfeeding power to klystron with a safe and good level of required\nquality. Up to 65 kV and a Load current in excess of 18 A was imparted\nto klystron with a trapezoidal pulse of voltage. Repeatability of\noperation is shown by successive shot results. RHVPS is explained with\nits scheme and control system. Basic parameters are fulfilled with a\nDummy Load testing of RHVPS. Test results are illustrated for basic\nparameters with resistive Dummy Load. LHCD system operation parameters\nand experimental parameters of RHVPS for its operation are discussed. A\nregulation on flat top level of voltage is as per the requirement of\nLHCD system. Initial integration of RHVPS has been successful and future\nplans are mentioned for full-fledged SST-1 operation.
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Initial integration of “regulated high voltage power supply” (RHVPS) with LHCD system of SST-1
2013 IEEE 25th Symposium on Fusion Engineering (SOFE), 2013Co-Authors: P.j. Patel, C. B. Sumod, Laxmi N. Gupta, Vishnu B. Patel, Vijay Vadher, Pushp Sharma, D. P. Thakkar, L. K. Bansal, K. Qureishi, K. K. AmbulkarAbstract:A Regulated High Voltage Power Supply (RHVPS) and its results are presented for its initial integration and operation with LHCD system. Experimental results are shown to show the ability of RHVPS as a practical source of electrical power for LHCD. Klystron is operated at 3.7 GHz. with a continuous wave (CW) RF power level of 500 kW with various subsystems. RHVPS has proven its capability for feeding power to klystron with a safe and good level of required quality. Up to 65 kV and a Load current in excess of 18 A was imparted to klystron with a trapezoidal pulse of voltage. Repeatability of operation is shown by successive shot results. RHVPS is explained with its scheme and control system. Basic parameters are fulfilled with a Dummy Load testing of RHVPS. Test results are illustrated for basic parameters with resistive Dummy Load. LHCD system operation parameters and experimental parameters of RHVPS for its operation are discussed. A regulation on flat top level of voltage is as per the requirement of LHCD system. Initial integration of RHVPS has been successful and future plans are mentioned for full-fledged SST-1 operation.
Sarath Perera - One of the best experts on this subject based on the ideXlab platform.
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Autonomous operation of wind-battery hybrid power system with maximum power extraction capability
2010 International Conference on Power System Technology, 2010Co-Authors: Nishad Mendis, Kashem M. Muttaqi, Saad Sayeef, Sarath PereraAbstract:The hybrid operation of a remote area power system consisting of a Doubly Fed Induction Generator (DFIG) based wind turbine, a battery storage unit and a Dummy Load is investigated in this paper. The battery storage unit operates as a source or Load, depending on the wind power output and Loading conditions of the system. The battery storage is connected to the AC side of the wind energy system through a three phase inverter to supply both active and reactive power. A Dummy Load is also incorporated into the AC side of the system. The design criteria of the controllers for each component (ie. DFIG, battery storage system and Dummy Load) and an approach for control coordination of the entire system are presented in this paper. The suitability of the proposed control coordination strategy and individual system controllers are tested in relation to the system voltage, frequency and DC link stability of the DFIG under variable wind and changing Load conditions. The maximum power extraction capability from wind is also achieved throughout the operation.
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Control coordination of a wind turbine generator and a battery storage unit in a Remote Area Power Supply system
IEEE PES General Meeting, 2010Co-Authors: Nishad Mendis, Kashem M. Muttaqi, Saad Sayeef, Sarath PereraAbstract:A novel hybrid Remote Area Power Supply (RAPS) system consisting of a Doubly Fed Induction Generator (DFIG) based wind turbine and a battery Energy Storage System (ESS) is investigated in this paper. The proposed RAPS system also consists of a Dummy Load and its controller. The battery energy storage system is used as a buffer which is connected to the DC link of the DFIG. The Dummy Load which is connected to the AC side of the system is used to absorb the energy associated with over generation, a situation which cannot be handled through the battery system. Control coordination of the Dummy Load and battery storage system helps maintain the system instantaneous power balance thus ensuring the regulation of the system frequency. The suitability of the proposed RAPS system is assessed in terms of the bandwidth of voltage regulation capability. Small signal model analysis although simpler to perform, is undertaken with a view to compare some of the corresponding results with those obtained using detailed models. Detailed modular simulation of the system is discussed in relation to the system voltage, frequency, DC link stability of the doubly fed induction generator and power sharing among different system components. The model of the entire system has been developed using SimPowerSystem toolbox in MATLAB.
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Power generation in isolated and regional communities: Application of a doubly-fed induction generator based wind turbine
2009Co-Authors: Nishad Mendis, Kashem M. Muttaqi, Saad Sayeef, Sarath PereraAbstract:The application of a Doubly Fed Induction Generator (DFIG) as a suitable generating scheme in a remote or isolated communities is presented in this paper. Remote Area Power Supply (RAPS) system, a Dummy Load and its controller with Energy Storage System (ESS) are identified as the key components. The Dummy Load is used to absorb the power associated with over generation. The battery storage system is used as a storage buffer which could absorb or release the power into the RAPS system when required. It is also used as a secondary control for the DC link voltage of the back-back converter of the DFIG. The hybrid operation of the DFIG, Dummy Load, ESS and main Load is discussed in relation to the system voltage,frequency and DC link stability. The entire hybrid model has been developed using the SimPowerSystem tool box in MATLAB.
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Voltage quality behaviour of a wind turbine based Remote Area Power System
2009 IEEE International Conference on Industrial Technology, 2009Co-Authors: Nishad Mendis, Kashem M. Muttaqi, Sarath PereraAbstract:The power quality behaviour of a Remote Area Power System (RAPS) consisting of a Doubly Fed Induction Generator (DFIG), its main Loads and a Dummy Load is presented in this paper. The Dummy Load is used to maintain the power balance of the system under changing wind and Loading conditions. The performance of the remote area power system subject to various Loading conditions has been evaluated in terms of the voltage quality, an aspect which has not received much attention in the past. The existing Distributed Generation (DG) power quality standards are taken as the basis to compare the voltage quality of the simulated waveforms. The simulation results indicate that the system evaluated is able to maintain the Load bus bar voltage and frequency within tight limits whereas a better harmonic performance can be achieved if adequate filtering is employed. The model was developed using SimPowerSystem tool box in MATLAB.
