Transistorised induction heating power supplies using MOSFET's

A prototype has been designed and constructed that has fed 3kW into a Commercial workcoil at 150 kHz. Another lower power inverter has been built. This was developed with ease of production in mind to aid the transfer of technology to the sponsoring company. The company have adopted this unit and are manufacturing it. The thesis reviews induction heating power supplies with emphasis on those able to operate above 100 kHz. Members of the MOSFET family are described and critically assessed for the application Prototypes of various configurations have been constructed and experience of these has led to the choice of current fed topology as the best for the application. The design and layout of a three phase current fed full bridge inverter that can feed 5 kW into an industrially relevant coil at 400 kHz and a single phase 2.5 kW version are described. Results of tests carried out on the units are presented. A microprocessor system has been selected which has been used for closed loop control of power, temperature and housekeeping tasks such as the supervision of interlocks.