A Report on 12th Thomas Alva Edison Memorial Lecture
For the year 2008, Delhi's 12th Thomas Alva Edison
Memorial Seminar was delivered by Dr. Milan Jovanovic, CTO (Chief Technology Officer) Power Systems
Business Group, Delta Electronics, Inc., Taiwan, and IEEE Fellow, on the topic ‘Technologies for Green Power Supplies -The
Efficiency Challenge’ with venue as the Committee Room (Block II-241, 1st Floor), in the
premises of the Department of Electrical Engineering, IIT Delhi, New
Delhi on September 29, 2008 (Monday). It started at 05.30 P.M. and continued
for one and half hour.
Dr. Milan has
started his talk on need of efficiency challenge and high power density in the
technologies
for green power supplies for telecommunications, data-communications and computing
systems. The development of high efficiency power supplies is principally carried
out for the desktop computers,
workstations and some low-end and mid-range servers. He has discussed a number
of configurations of power supply systems and reduced number of components,
improved packaging, reducing the stages to enhance the efficiency and
compactness. He has explained practically achieved efficiency of the order of 90-95%
over the wide range of load variations and a power density of the order of 25-40
W/in3. Typical frequency range of today’s
switch-mode power supplies is from 80 kHz to 1 MHz to reduce the size of
transformer and other energy storage elements such as inductors and capacitors
etc. for providing high efficiency and compact structure of these power supply
systems.
He has clarified a new focus on entire load
efficiency and low voltage power supplies for energy conservation and reduced
carbon emission. Power factor correction (PFC) is considered a major
consideration in these power supplies to emulate them as a resistor and reduced
pollution at ac mains in terms reduced harmonics current injection and reactive
power burden.
He
clarified that the implementation of intelligent controllers through use of
DSPs (Digital Signal Processors) due to reduced cost of the processors in these
power supplies is no more luxury but it has become the necessity of new and
modern systems to provide diagnostic features and status monitoring. The use of
soft switching technology in these power supplies is the need of the hour to
reduce the switching losses through ZVS (Zero voltage switching) and ZCS (Zero
current switching) of solid state devices switching. Moreover, the use of silicon carbide and
other new materials in solid state devices with drastically reduced voltage
drop during conduction, has given the boost to enhance the efficiency of the
converters used in these new green power supplies.
This presentation was of interest to all power, energy, power
electronics engineering professionals, who came from academic institutions as
well as power utilities and equipment manufacturers. In all 71 persons (7 IEEE
Members and 64 others) attended the event.
