Automated Calculation Method to Determine the Output Power Based on the Frequency for Induction Heating IGBT Parallel Inverter

The fact that some inverter topologies used in induction heating applications allow the soft switching working operation lets the progressive replacement of the MOSFET with the IGBT in high power inverters. This is due to two main reasons, the former is the IGBT reliability and the latter is the ratio defined as the price of the component per output power. In this article an automated method to determine the output power based on the frequency of an inverter build with different IGBT is described. To carry out this method is necessary to define the power cycle and to develop the calculation process which determines the energy losses in the working conditions of the resonant parallel inverter. A practical setup is required to validate the turn off energy losses calculation because the data given by the manufacturer is for a different type of switching. In the following text it is explained the general method and then it is described its application for three IGBT. The theoretical results obtained are compared with the experimental measures taken in a 100 kW inverter..