Abstract
M.Ing. (Electrical & Electronic Engineering)
Induction heating is a relatively old and established process. New switching
devices and ideas are, however, resulting in much improved performance at
reduced cost. Some of these devices are investigated in this thesis, and some
new ideas presented.
From a literature study a general review of the current state of the technology
is given. The fundamental principles and limits of induction heating are discussed.
Power electronic topologies for induction heating, as well as switching
devices which can be used in these topologies, are compared and evaluated.
From the knowledge gained, possible fields for improvement are identified. One
such field is that of semiconductor switch drives, and a high-performance gate
drive was developed. Using such fast drives, special attention must be given to
the electromagnetic layout of the circuit.
Another new field is that of integrated resonant elements. These elements find
application in most resonant converters, and offer reduced weight and losses
compared to conventional technologies. They are evaluated both experimentally
and theoretically.
A prototype induction heater was built, using a newly released switching device
named a zero turn-off thyristor. The high-performance gate drive developed
earlier was tested in the inverter and gave excellent results.