The Experts below are selected from a list of 18057 Experts worldwide ranked by ideXlab platform

Jihsheng Lai - One of the best experts on this subject based on the ideXlab platform.

  • modeling and control of a novel six leg three Phase high power converter for low voltage fuel cell applications
    IEEE Transactions on Power Electronics, 2006
    Co-Authors: Changrong Liu, A Ridenour, Jihsheng Lai
    Abstract:

    In this paper, an averaged model for a recently proposed novel three-Phase Transformer-isolated Phase-shift dc-dc converter is derived. Fuel cell static and dynamic characteristics are used for the converter power stage design consideration. The controller is then designed based upon the power stage parameters and system dynamic requirements. The entire system has been designed, fabricated, and tested using a commercial 1.2-kW proton exchange membrane fuel cell. The experimental results match the simulation results fairly well on both fuel cell source dynamic and step load transient responses

Xiangang Luo - One of the best experts on this subject based on the ideXlab platform.

  • design of a Phase Transformer using coordinate transformation theory
    IEEE PhotonicsGlobal, 2008
    Co-Authors: Lan Lin, Wei Wang, Changtao Wang, Xiangang Luo
    Abstract:

    New electromagnetic devices with extraordinary characteristics have been designed by form-invariant coordinate transformation of Maxwell's equations successfully. Here, a Phase Transformer was designed in this way. The wave front can change from cylindrical to plane through this Transformer with a slab structure and the propagation direction of electromagnetic energy in this device can be modulated as designed. Finally, two dimensional finite-element simulations were performed to confirm this result.

  • design of electromagnetic refractor and Phase Transformer using coordinate transformation theory
    Optics Express, 2008
    Co-Authors: Lan Lin, Wei Wang, Jianhua Cui, Chunlei Du, Xiangang Luo
    Abstract:

    We designed an electromagnetic refractor and a Phase Transformer using form-invariant coordinate transformation of Maxwell’s equations. The propagation direction of electromagnetic energy in these devices can be modulated as desired. Unlike the conventional dielectric refractor, electromagnetic fields at our refraction boundary do not conform to the Snell’s law in isotropic materials and the impedance at this boundary is matched which makes the reflection extremely low; and the transformation of the wave front from cylindrical to plane can be realized in the Phase Transformer with a slab structure. Two dimensional finite-element simulations were performed to confirm the theoretical results.

A Bellini - One of the best experts on this subject based on the ideXlab platform.

  • 3boost a high power three Phase step up full bridge converter for automotive applications
    IEEE Transactions on Industrial Electronics, 2008
    Co-Authors: G Franceschini, Emilio Lorenzani, M Cavatorta, A Bellini
    Abstract:

    This paper describes a simple dc-dc step-up converter topology for switch-mode dc power supplies. The proposed configuration is well suited for high-power applications with battery supply. In the automotive framework, the push-pull architecture is the most widespread. However, as power increases, the use of a full-bridge architecture is mandatory. This paper presents a full-bridge architecture where the traditional single-Phase Transformer is replaced by a three-Phase Transformer. A prototype was realized and tested for the power supply of automotive devices. In this environment, one of the most important requirements is the ability to provide a burst of power during short-duration events, together with high-efficiency and high-quality output voltage. The latter constraints can be achieved by only using closed-loop switch-mode dc-dc converters at high switching frequency, thus reducing converter efficiency and creating electromagnetic-compatibility (EMC) problems. In this paper, the aforementioned issues were tackled relying on an open-loop topology. Open-loop converters are feasible if the output resistance of the converter is as low as possible, and a possible solution is the minimization of power losses. The solution is the use of a three-Phase Transformer with a delta-wye connection within a full-bridge converter topology. The configuration will be referred to as 3boost power supply. The three-Phase Transformer replaces the common single-Phase Transformer, and it is driven by a three-Phase full-bridge inverter operating in six-step modulation. At secondary, a three-Phase full wave diode rectifier is used to obtain the output dc voltage level. Therefore, a unitary Transformer utilization factor is achieved. A simple theoretical comparison between the three types of converters-push-pull, conventional full bridge, and 3boost is shown. A low-power version of the converter was realized. Experiments confirm that this topology allows to achieve a high efficiency, a lower ripple factor, and a good EMC behavior.

  • 3boost a high power three Phase step up full bridge converter for automotive applications
    Conference of the Industrial Electronics Society, 2004
    Co-Authors: G Franceschini, Emilio Lorenzani, M Cavatorta, A Bellini
    Abstract:

    This paper presents a simple and original DC/DC step-up converter topology for switch-mode DC power supplies. The proposed architecture is well suited for high power applications with battery supply. A prototype was realized and tested for the power supply of automotive devices. In this environment signals are characterized by high dynamic variations, thus they can be operated only relying on power supplies with high dynamic capabilities. The latter constraint can be achieved only using closed-loop switch-mode DC/DC converters at high switching frequency. So doing converter efficiency is reduced, and EMC problems arise. In summary power supply efficiency and supply voltage quality are key features of the converter design. In this paper the above mentioned issued were tackled relying on an open loop topology. The original solution is the adoption of a three-Phase Transformer with delta-wye connection within a full-bridge converter topology. The proposed architecture will be referred to as 3boost power supply. The three-Phase Transformer replaces the common single-Phase Transformer and it is supplied at primary by three square waves, produced by a three-Phase full bridge inverter. At secondary a three-Phase full wave diode rectifier is used to obtain the output DC voltage level. Experimental results confirm that this topology, with respect to a single-Phase push-pull converter, allows to achieve higher efficiency, a lower ripple factor, and a unitary Transformer utilization factor. The proposed architecture is patent pending.

Vivek Agarwal - One of the best experts on this subject based on the ideXlab platform.

  • novel Transformer less inverter topology for single Phase grid connected photovoltaic system
    Photovoltaic Specialists Conference, 2015
    Co-Authors: Mini Rajeev, Vivek Agarwal
    Abstract:

    This paper proposes a new inverter topology based on the operation of C□uk converter for single-Phase Transformer-less grid connected photovoltaic system. In this topology, since the grid neutral is directly connected to the negative terminal of the photovoltaic (PV) array, there is no common mode voltage variation across the parasitic capacitance of the array and the leakage current is eliminated completely. The proposed topology has voltage boosting capability and the efficiency is comparable with H5 inverter. Simulation is done for feeding 500W PV power in to the grid and the results are presented and analyzed. Hardware implementation of the system is carried out and results are included in the paper.

  • a single stage single Phase Transformer less doubly grounded grid connected pv interface
    IEEE Transactions on Energy Conversion, 2009
    Co-Authors: Hiren H Patel, Vivek Agarwal
    Abstract:

    A Transformer provides galvanic isolation and grounding of the photovoltaic (PV) array in a PV-fed grid-connected inverter. Inclusion of the Transformer, however, may increase the cost and/or bulk of the system. To overcome this drawback, a single-Phase, single-stage [no extra converter for voltage boost or maximum power point tracking (MPPT)], doubly grounded, Transformer-less PV interface, based on the buck-boost principle, is presented. The configuration is compact and uses lesser components. Only one (undivided) PV source and one buck-boost inductor are used and shared between the two half cycles, which prevents asymmetrical operation and parameter mismatch problems. Total harmonic distortion and DC component of the current supplied to the grid is low, compared to existing topologies and conform to standards like IEEE 1547. A brief review of the existing, Transformer-less, grid-connected inverter topologies is also included. It is demonstrated that, as compared to the split PV source topology, the proposed configuration is more effective in MPPT and array utilization. Design and analysis of the inverter in discontinuous conduction mode is carried out. Simulation and experimental results are presented.

Mustafa Bagriyanik - One of the best experts on this subject based on the ideXlab platform.

  • characterization of transients in Transformers using discrete wavelet transforms
    IEEE Transactions on Power Systems, 2003
    Co-Authors: Karen L Butlerpurry, Mustafa Bagriyanik
    Abstract:

    This paper presents the characterization of transients resulting from faults in Transformers using discrete wavelet transform (DWT). This characterization will aid in the development of an automatic detection method for internal incipient faults in the Transformers. The detection method can provide information to predict failures ahead of time so that the necessary corrective actions are taken to prevent outages and reduce down times. The analyzed data are obtained from simulations and experiments for different normal and abnormal operating cases such as external faults, internal short circuit faults, magnetizing inrush, and internal incipient faults. The simulation method and experiment setup are discussed. The experiments and simulations are conducted on a single-Phase Transformer as an example case. The results of applying the DWT are discussed.