Harmonic Analyses of a Voltage Fed Induction Furnace

It is already known that the efficiency of the induction heating furnace (IHF) is very low as compared with that of other electromagnetic equipment's like transformers or rotating machines. This is due to the ordinary switching losses in its power supply, and the power dissipated in the conductors connecting its parts. The conductors' losses are due to the huge current harmonics in the different parts of the IHF power supply since it is composed of a fully controlled full wave rectifier (FCFWR) feeding a single-phase H-bridge inverter. In this work a 50-kW voltage fed IHF is simulated using MATLAB computer package, to determine the generated harmonics in each part of the system in different operating conditions. The load parameters in each case assumed constant in this analysis, in spite of their dependency on temperature variation during the heating process. Since, the effective resistances for each harmonic current passing in certain conductor depends on its harmonic frequency, then this will decide the power dissipated due to that harmonic. This approach will be adopted in this work, and an interesting results, conclusions, and recommendations achieved to improve the efficiency of the IHF power supply.