Power quality improvement for single phase and three phase current source induction heating systems

With the increasing application of Induction Heating (IH) systems in various industries such as metallurgy, concerns about the harmonic effects and power quality of the power grid have been involved in the problems facing network operation engineers. This paper presents methods to improve the power quality of induction heating systems. Current Source Parallel Resonant Inverter (CSPRI) is mostly used for IH systems. For three-phase current source IH system a new soft starting method with single tuned passive filters is used to reduce sag voltage and harmonic distortions. For single phase applications a new topology is presented to reduce harmonic distortions. In this paper the current source induction heating system is modeled and the transient and steady state behaviors of the system are simulated. For single phase topology a low power laboratory prototype is implemented with operating frequency of 60 kHz; the experimental results and simulation results are in good agreement.