ITEE Ph.D confirmation seminar: Paul Sernia, 10.00AM, Tue 22 Jul 2003

Random Modulation in Multilevel Converters for Distributed Generation Applications

Speaker: Paul Sernia, ITEE

When: 10.00AM, Tuesday 22 Jul 2003

Venue: 78-622

Host: Dr Geoff Walker

Abstract:

  Integration of renewable energy technologies into the electrical
  power generation market will require a shift from a centralised
  model, using a few high-power generating plants, to a distributed
  generation (DG) model consisting of many low-power generating
  plants.  Examples of suitable renewable technologies are solar
  cells, hybrid-electric vehicles, batteries or fuel cells.  All of
  these technologies can provide power to the grid in times of high
  demand, reducing the load on conventional generating plants and
  storing excess energy from the grid at off-peak times.  These
  renewable energy sources are typically comprised of collections of
  low-voltage DC sources, requiring specialised electronics to
  interface them to a high-voltage AC output.  One particularly
  suitable power electronics converter design is the cascaded
  multilevel converter.  This architecture offers efficient power flow
  control on a 'per cell' basis as well as advantages in terms of
  low-order harmonic cancellation.  A traditional mutlilevel converter
  requires that switches be synchronised for proper harmonic
  cancellation.  The problem arises in a cascaded multilevel converter
  that the cascaded 'modules' may not be physically adjacent to each
  other, especially for renewable power applications such as solar
  energy, and the cost of implementing fast, intelligent
  communications between modules becomes prohibitive.  To date,
  previous applications have used only a low number of modules and the
  DC sources have been arranged in close physical proximity.

  This seminar introduces the idea of using random modulation
  techniques in place of synchronised switching between cascaded
  modules.  Random modulation has been shown to reduce harmonic
  spectra of a switchmode converter, although not to the extent
  achieved in multilevel converters.  This is overcome by increasing
  the number of cascaded modules, since tight synchronisation is no
  longer required.  Initial study results are presented to show the
  extent to which harmonic cancellation occurs in a random situation
  for increasing numbers of cascaded modules.  These results are
  compared with traditionally controlled cascaded multilevel
  converters and further strategies for improvement are discussed.

Biography:

(biography unavailable)

Type:

Ph.D confirmation

Contact:

Dr Geoff Walker, seminar host (walkerg@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator) (guido@itee.uq.edu.au)

ITEE seminar web page: http://www.itee.uq.edu.au/~seminar

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