Online IGBT temperature measurement method using a greybox model

A novel temperature measurement method using only gate signals is presented. The temperature dependency of the internal gate resistance is used. First a transfer function of the equivalent gate circuit is derived and transformed into discrete time. Measurement data from the gate circuit, i.e. the voltage on both sides of the external gate resistance w.r.t. the emitter potential are taken and used for parameter identification of the grey-box model. From these parameters the value of the internal gate resistance, which is temperature dependent, is derived.