Dynamic load impedance matching for induction heater systems
It is not normally possible to heat a static steel work-piece past the Curie temperature without incurring reduced inverter utilisation. Since the inverter cost increases with rated power, reduced utilisation implies an increase in investment costs for a given performance. The paper shows that third-order resonant work-head circuits can intrinsically allow better utilisation of the inverter for variable-load heating operations. A further refinement is then shown to allow control of the load impedance, thereby allowing the utilisation to approach 100 percent over the heating cycles.
impedance heat transfer electrical machines