Real-time power electronic device junction temperature estimation

Temperature management and control are among the most critical functions in power electronic devices, as operating temperature and thermal cycling can affect performance and reliability. Therefore, it is useful to develop a device thermal model, which can be implemented in real-time and used to estimate temperature variations within the active region of the device. This paper develops a device thermal model suitable for a MOSFET power-switching device. The real-time thermal model is implemented in a digital signal processor (DSP) and used for device temperature estimation. The technique is illustrated by estimation of the temperature distribution in a sample MOSFET device at low and high power cycling frequencies showing the transient and steady state thermal responses. These results are compared with real-time temperature device measurements.