Controls and Control Theory Commons^™

Self-Oscillating Induction Heater, Patrick Rice

Dissertations, Master's Theses and Master's Reports

This report develops a control system to keep an induction heater in resonance. When a metallic workpiece is inserted in the air core of the workcoil, the resonant frequency changes. Different workpiece materials affect the resonant frequency and power. This presents a problem since changing the resonant frequency of the circuit while keeping the frequency constant reduces the maximum power of the circuit. Finite element analysis is used to find the circuit parameters of the workcoil and workpiece interaction. A non-linear controller which oscillates based on the resonant frequency of an LC tank is created. Nyquist and describing function analysis …