The Design Of An Intermediate Frequency Induction Heating Power Supply

An intermediate frequency induction heating power for soft product package as soft container sealing machine is designed with series resonant load. The power can not only increase the melting point of the sealing material rapidly in one or two seconds but also can protect the product. The qualification of the power that use the full bridge inverter circuit with MOSFET is that voltage of 220V,50Hz input and voltage of 220V,600Hz output with the power of 4kW.Intermediate frequency induction heating power supply is researched in this paper. I try to choose the PWM controller SG3525 to make the SPWM controlling circuit. The virtual power technology which differentiates from the real ground is applied in the controlling circuit to make it simple. The 600Hz pure Sin waves from Wien-bridge oscillation circuit is processed by closed loop stabilization circuit and rectify circuit to get the 2.3VPP Steamed bread wave which can get 20 kHz SPWM pulse. The pulse is combined with a square wave of 600Hz to get a 600Hz SPWM pulse through the sequential circuits and dead zone adjustment circuit to drive the IRFP460 with TLP250. The controlling circuit has self-protected function of over heat and over current. The load is RLC series resonant circuit. The circuit can get the low DC from the fly back type switch power supply based on TOP Switch-II.As the experiment results show, the output of the power is in accordance with the simulation of circuits, and can get the expected results. The output capacity of the intermediate frequency induction heating power keeps stabile and is in keep with the design.