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Low-cost, industrial class-E power amplifiers with sine-wave drive


Davis, John F. (2000) Low-cost, industrial class-E power amplifiers with sine-wave drive. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/j5vk-kx77.


The Class-E amplifier is a switching-mode amplifier in which the transistor operates as a switch with a passive, resonant load network. Losses are minimized by having the transistor switch on when both the voltage and current are small. These amplifiers are extremely efficient with about 90% of the DC input power converted to RF output power. This thesis will present two high-power Class-E amplifiers designed for the Industrial, Scientific, and Medical (ISM) frequency of 13.56 MHz. The first is a 200-W amplifier that incorporates the inexpensive International Rectifier IRFP440 MOSFET. With a drive level of 10 W, a drain efficiency of 91% and an overall efficiency of 87% are achieved. The second is a 400-W, air-cooled design that uses a new International Rectifier low-charge MOSFET, the IRFP450LC. This device features improved switching speed and reduced gate drive requirements. A drive level of 12 W is used to attain a drain efficiency of 86% and an overall efficiency of 84%. In both amplifiers, all harmonics are more than 40 dB below the carrier. Design procedures, modelling techniques, and extensive experimental results will be presented for each. In addition, results from a thermal study of a 400-W Class-E amplifier will be discussed. Component and junction temperature data are obtained by a direct measurement technique, Infrared Thermographic Imaging or Thermography and compared with simulated results. Particular attention is paid to the MOSFET and load network capacitors.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Electrical Engineering
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Rutledge, David B.
Thesis Committee:
  • Unknown, Unknown
Defense Date:2 December 1999
Record Number:CaltechTHESIS:10012010-115944627
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6086
Deposited By: Benjamin Perez
Deposited On:01 Oct 2010 21:18
Last Modified:16 Apr 2021 23:15

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