Virginia Tech
    • Log in
    View Item 
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Performance Improvements of Multi-Channel Interleaving Voltage Regulator Modules with Integrated Coupling Inductors

    Thumbnail
    View/Open
    ETS_pwong.pdf (1.910Mb)
    Downloads: 3717
    Date
    2001-03-28
    Author
    Wong, Pit-Leong
    Metadata
    Show full item record
    Abstract
    The emergence of the Intel Pentium TM processor necessitates that a dedicated converter, the voltage regulator module (VRM), be physically located very close to the processor in computer power systems. The efficiency and transient response specifications of the VRM place contradictory requirements on the inductance. This dissertation discusses possible VRM inductor designs to improve efficiency without compromising transient responses. The multi-channel interleaving buck converter is the most popular topology for present VRMs. Analysis in this work shows that the small-signal model of an n-channel interleaving buck can be simplified as a single buck converter. The equivalent inductance is 1/n of the inductance in the interleaving channel. The equivalent switching frequency is n times the switching frequency in each channel. Through the transient response analysis, the critical inductance of the VRM is identified. The critical inductance is a tradeoff point between transient response and efficiency. The inductances smaller than the critical inductance have equal transient responses. For the inductances larger than the critical inductance, the VRM transient voltage spikes increase with the inductance. The critical inductance is the largest inductance that gives the fastest transient responses. The critical inductance is a function of the control bandwidth and the load transient steps. Although multi-channel interleaving reduces the current ripple stress on the output capacitors, it cannot reduce the current ripples in each channel. The large current ripples reduce the efficiency of the VRM. With the proposed concept of integrated coupling inductors between channels, the converters have larger equivalent inductances in steady-state operation and smaller equivalent inductances in transient response. The steady-state current ripples can be reduced without compromising the transient response. The overall efficiency of the converter is improved. In order to evaluate the application of the coupling inductor concept in multi-channels, an appropriate magnetic model is required. This dissertation proposes a flux reluctance model for the core and winding structures. With this reluctance model and mathematical transformations, the coupled inductors can be decoupled in the electric circuit simulation model. This reduces the complexity of the model when a large number of inductors are coupled. The model can be easily scaled to model the structures that involve more inductors. Examples are presented to show the application of this proposed model.
    URI
    http://hdl.handle.net/10919/27148
    Collections
    • Doctoral Dissertations [14977]

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us
     

     

    VTechWorks

    AboutPoliciesHelp

    Browse

    All of VTechWorksCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Log inRegister

    Statistics

    View Usage Statistics

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us