The Experts below are selected from a list of 2859 Experts worldwide ranked by ideXlab platform

K H Norian - One of the best experts on this subject based on the ideXlab platform.

  • equivalent circuit components of nickel cadmium battery at different states of charge
    Journal of Power Sources, 2011
    Co-Authors: K H Norian
    Abstract:

    Abstract Equations that describe the Voltage variations with time of a rechargeable battery during charging and discharging were used to determine the component values of the equivalent circuit of nickel–cadmium batteries under different states of charge (SOC). The equivalent circuit of the battery was described as an Ideal Voltage Source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model used different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge-rest–charge-rest sequence. The results show that the series resistance is approximately constant with variations in the SOC while the resistor in the parallel RC circuit increases as the SOC decreases. For the discharge and charge phases the capacitor value increased and decreased, respectively, as the SOC decreased. The value of the resistor or capacitor in the parallel RC circuit is an indicator of the battery SOC.

  • equivalent circuit components of nickel cadmium battery at different states of charge
    Journal of Power Sources, 2011
    Co-Authors: K H Norian
    Abstract:

    Abstract Equations that describe the Voltage variations with time of a rechargeable battery during charging and discharging were used to determine the component values of the equivalent circuit of nickel–cadmium batteries under different states of charge (SOC). The equivalent circuit of the battery was described as an Ideal Voltage Source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model used different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge-rest–charge-rest sequence. The results show that the series resistance is approximately constant with variations in the SOC while the resistor in the parallel RC circuit increases as the SOC decreases. For the discharge and charge phases the capacitor value increased and decreased, respectively, as the SOC decreased. The value of the resistor or capacitor in the parallel RC circuit is an indicator of the battery SOC.

  • transient boundary Voltage method for measurement of equivalent circuit components of rechargeable batteries
    Journal of Power Sources, 2011
    Co-Authors: K H Norian
    Abstract:

    Abstract A method is presented for measuring the equivalent circuit components of rechargeable batteries. The temporal discharge–rest–charge–rest sequence of a rechargeable battery is described, using the principles of transient circuit analysis, to derive equations for the battery Voltage as a function of time during Voltage transients and at the boundaries at transitions between transient phases. The equations lead to a new measurement method for battery characterization. The equivalent circuit of the battery is described as an Ideal Voltage Source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model uses different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge–rest–charge–rest sequence. The method is used to measure the circuit parameters of a nickel–cadmium battery.

Murali R Sachithanandam - One of the best experts on this subject based on the ideXlab platform.

  • neural network based control strategy for hybrid dstatcom in three phase four wire distribution system under non Ideal Voltage Source conditions and varying load conditions
    International Review of Electrical Engineering-iree, 2015
    Co-Authors: J Jayachandran, Murali R Sachithanandam
    Abstract:

    In this paper the choice of power quality compensator is a DSTATCOM which constitutes a four leg Voltage Source converter (VSC) and a DC capacitor. An artificial neural network (ANN) based synchronous reference frame (SRF) theory is proposed for the generation of gating pulse of the DSTATCOM to balance the Source current, eliminate harmonics and to compensate neutral current and reactive power in three phase four wire (3P4W) distribution system. In the proposed control strategy ANN controllers replace the PI controllers and low pass filters of conventional method. ANN controllers are also implemented to keep up the Voltage across the capacitor and as a compensator to compensate neutral current under unbalanced load conditions. Various transformer topologies are simulated and compared with the proposed control strategy for compensation of neutral current. The DSTATCOM performance is adjudged under balanced, unbalanced and/or distorted Voltage Source conditions through simulation using MATLAB software. Data extracted from the experiment conducted in the laboratory to study the effect of non-linear load are used in the simulation to prove the efficacy of the proposed control strategy in power quality improvement.

J Jayachandran - One of the best experts on this subject based on the ideXlab platform.

  • neural network based control strategy for hybrid dstatcom in three phase four wire distribution system under non Ideal Voltage Source conditions and varying load conditions
    International Review of Electrical Engineering-iree, 2015
    Co-Authors: J Jayachandran, Murali R Sachithanandam
    Abstract:

    In this paper the choice of power quality compensator is a DSTATCOM which constitutes a four leg Voltage Source converter (VSC) and a DC capacitor. An artificial neural network (ANN) based synchronous reference frame (SRF) theory is proposed for the generation of gating pulse of the DSTATCOM to balance the Source current, eliminate harmonics and to compensate neutral current and reactive power in three phase four wire (3P4W) distribution system. In the proposed control strategy ANN controllers replace the PI controllers and low pass filters of conventional method. ANN controllers are also implemented to keep up the Voltage across the capacitor and as a compensator to compensate neutral current under unbalanced load conditions. Various transformer topologies are simulated and compared with the proposed control strategy for compensation of neutral current. The DSTATCOM performance is adjudged under balanced, unbalanced and/or distorted Voltage Source conditions through simulation using MATLAB software. Data extracted from the experiment conducted in the laboratory to study the effect of non-linear load are used in the simulation to prove the efficacy of the proposed control strategy in power quality improvement.

Vinicius Stramosk - One of the best experts on this subject based on the ideXlab platform.

  • modeling and stability analysis of islanded dc microgrids under droop control
    IEEE Transactions on Power Electronics, 2015
    Co-Authors: Andre Pires Nobrega Tahim, Daniel J Pagano, Eduardo Lenz, Vinicius Stramosk
    Abstract:

    The stability of dc microgrids (MG s ) depends on the control strategy adopted for each mode of operation. In an islanded operation mode, droop control is the basic method for bus Voltage stabilization when there is no communication among the Sources. In this paper, it is shown the consequences of droop implementation on the Voltage stability of dc power systems, whose loads are active and nonlinear, e.g., constant power loads. The set of parallel Sources and their corresponding transmission lines are modeled by an Ideal Voltage Source in series with an equivalent resistance and inductance. This approximate model allows performing a nonlinear stability analysis to predict the system qualitative behavior due to the reduced number of differential equations. Additionally, nonlinear analysis provides analytical stability conditions as a function of the model parameters and it leads to a design guideline to build reliable (MG s ) based on safe operating regions.

John Z Shen - One of the best experts on this subject based on the ideXlab platform.

  • characteristics and restraining method of fast transient inrush fault currents in synchronverters
    IEEE Transactions on Industrial Electronics, 2017
    Co-Authors: Zhikang Shuai, Wen Huang, Chao Shen, Jun Ge, John Z Shen
    Abstract:

    Large transient inrush fault current in a synchronverter during a short-circuit fault can potentially damage the inverter and cause grid instability. It is therefore important to study the characteristics of and the way to restrain the inrush fault current. This paper investigates the characteristics of the synchronverter inrush fault current and proposes a new control method based on mode switching to protect synchronverters. First, an Ideal Voltage Source inverter instantaneous inrush current calculation method for a grid symmetrical short circuit is discussed. Then, based on the inertia of synchronverter, the approximate calculation of the synchronverter instantaneous inrush current is described. The results show that the synchronverter's inrush current mainly consists of a gradually attenuated periodic component and a dc component when the phased Voltage symmetry is lost. In our proposed new control approach, the synchronverter switches to the hysteresis controller to limit the output current quickly while staying connected to the grid, and supporting the grid Voltage simultaneously. Simulation and experiment results verify the validity of the theoretical analysis.