The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

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

  • A simplified control system for series connected, AC-DC PWM converters, for back-to-back multiterminal systems
    Proceedings of 1994 IEEE International Symposium on Industrial Electronics (ISIE'94), 1994
    Co-Authors: J.w. Dixon
    Abstract:

    Voltage source PWM rectifiers are able to work with near sinusoidal current waveforms and unity or even Leading Power Factor. From the point of view of the DC link, these rectifiers reverse Power through current instead of voltage reversal, allowing back-to-back multiterminal converter topologies. However, some problems related with this system are the complexity of the control circuit, the stability of the system and the DC voltage-sharing between converters. This paper analyzes these problems and proposes a simple solution. Based on the detection of the DC current instead of the DC voltage, using a unique and predefined PWM pattern, stored in an EPROM, for each converter. The patterns are phase shifted following the load current variations, allowing control of the voltage of the DC link. The main characteristics of this solution are: (a) there is no master rectifier (all are hierarchically identical); (b) the stability does not depends on the size of the DC capacitors; (c) it can work at Leading Power Factor for all load conditions; and (d) it can be adjusted to work at zero regulation. Computer simulations, mathematical analyses and some experimental results with a 2 kW voltage regulated PWM prototype are included in the paper.

  • A novel load current control method for a Leading Power Factor voltage source PWM rectifier
    IEEE Transactions on Power Electronics, 1994
    Co-Authors: J.w. Dixon
    Abstract:

    A novel PWM voltage source rectifier, controlled by the load DC current instead of the DC voltage, has been developed. Its main characteristics are: (a) there is neither input current sensors nor DC voltage sensor; (b) it works with an unchangeable and predefined PWM pattern; (c) it presents a very strong stability; (d) its stability does not depend on the size of the DC capacitor; (e) it can work at Leading Power Factor for all load conditions; and (f) it can also work with zero regulation for all load conditions. Digital simulations, analyses, and experiments confirm all these characteristics of the control method.

N. Brooks - One of the best experts on this subject based on the ideXlab platform.

  • An integrated approach for the calculation of losses and temperatures in the end-region of large turbine generators
    IEEE Transactions on Energy Conversion, 1990
    Co-Authors: G.k.m. Khan, G.w. Buckley, R.b. Bennett, N. Brooks
    Abstract:

    The finite-element method is applied to the design of the stator end-packets, the copper screen, and the clamping plate of a 1000 MW two-pole generator. The methods used are described, the results for flux density, loss intensity, and temperature distributions at the rated output and a Leading Power Factor of 0.95 are presented. The results provide insight into the phenomena occurring in the end-region of a large turbine generator and emphasize the significance of axial fluxes from end-heating considerations. The influence of some of the design parameters (for example, the width of stator packets) in controlling the packet temperatures is explained. The technique is validated from measurements on a 660 MW generator of a modern design, and the resulting good correlation shows that the techniques presented are reliable design tools.

V. T. Ranganathan - One of the best experts on this subject based on the ideXlab platform.

  • A Novel VSI- and CSI-Fed Active–Reactive Induction Motor Drive with Sinusoidal Voltages and Currents
    IEEE Transactions on Power Electronics, 2011
    Co-Authors: Kamalesh Hatua, V. T. Ranganathan
    Abstract:

    Till date load-commutated inverter (LCI)-fed synchronous motor drive configuration is popular in high Power applications (>;10 MW). The Leading Power Factor operation of synchronous motor by excitation control offers this simple and rugged drive structure. On the contrary, LCI-fed induction motor drive is absent as it always draws lagging Power Factor current. Therefore, complicated commutation circuit is required to switch off thyristors for a current source inverter (CSI)-driven induction motor. It poses the major hindrance to scale up the Power rating of CSI-fed induction motor drive. A new Power topology for LCI-fed induction motor drive for medium-voltage drive application is proposed. A new induction machine (active-reactive induction machine) with two sets of three-phase winding is introduced as a drive motor. The proposed Power configuration ensures sinusoidal voltage and current at the motor terminals. The total drive Power is shared among a thyristor-based LCI, an insulated gate bipolar transistor (IGBT)-based two-level voltage source inverter (VSI), and a three-level VSI. The benefits of SCRs and IGBTs are explored in the proposed drive. Experimental results from a prototype drive verify the basic concepts of the drive.

P. P. Rajeevan - One of the best experts on this subject based on the ideXlab platform.

  • load commutated scr based current source inverter fed induction motor drive with open end stator windings
    IEEE Transactions on Industrial Electronics, 2018
    Co-Authors: Richu Sebastian C, P. P. Rajeevan
    Abstract:

    A new topology of a load-commutated silicon-controlled rectifier (SCR)-based current source inverter (CSI)-fed induction motor drive with open-end stator winding is presented in this paper. The proposed topology has a CSI at one side of the stator winding and a capacitor-fed voltage source inverter (VSI) at the other end. The CSI feeds only active Power to the motor and the VSI is controlled to provide the reactive Power required for operation of the CSI at Leading Power Factor, thereby facilitating natural commutation of SCRs. This topology does not require any interfacing inductor or separate dc voltage source for the VSI. The control scheme enables operation of the motor even at very low speeds without problems such as commutation failure. The experimental verification of the proposed scheme is carried out on an induction motor with open-end stator windings. A digital signal processor (TMS320F28335) is used for implementation of the control algorithm.

  • Four quadrant operation of load commutated SCR based multilevel CSI fed open-end winding Induction motor drive
    2018 IEEE International Conference on Power Electronics Drives and Energy Systems (PEDES), 2018
    Co-Authors: Richu C Sebastian, P. P. Rajeevan
    Abstract:

    This paper presents four quadrant operation of load commutated SCR based multilevel current source inverter (CSI) fed open-end winding induction motor drive. Multilevel CSI consists of two current source inverters operated in phase shifted mode, connected to one end of the stator winding of open-end winding induction motor. Multilevel CSI is used to supply the real Power requirement of the system. The other end of the stator winding is interfaced with an IGBT based voltage source inverter (VSI) for reactive Power compensation alone. VSI maintains Leading Power Factor at the CSI terminal through reactive Power compensation and ensures load commutation of multilevel CSI. The proposed drive has retained its inherent regeneration capability and can be operated in all the four quadrants. This topology is experimentally verified on a 1. 5hP open-end winding induction motor with the help of a digital signal processor TMS320F28335.

G.k.m. Khan - One of the best experts on this subject based on the ideXlab platform.

  • An integrated approach for the calculation of losses and temperatures in the end-region of large turbine generators
    IEEE Transactions on Energy Conversion, 1990
    Co-Authors: G.k.m. Khan, G.w. Buckley, R.b. Bennett, N. Brooks
    Abstract:

    The finite-element method is applied to the design of the stator end-packets, the copper screen, and the clamping plate of a 1000 MW two-pole generator. The methods used are described, the results for flux density, loss intensity, and temperature distributions at the rated output and a Leading Power Factor of 0.95 are presented. The results provide insight into the phenomena occurring in the end-region of a large turbine generator and emphasize the significance of axial fluxes from end-heating considerations. The influence of some of the design parameters (for example, the width of stator packets) in controlling the packet temperatures is explained. The technique is validated from measurements on a 660 MW generator of a modern design, and the resulting good correlation shows that the techniques presented are reliable design tools.