Online Measurement of Power MOSFET Junction Temperature With Storage Charge During Current Fall Process

Power metal-oxide-semiconductor field-effect transistor (MOSFET) has been widely used in high-frequency power conversion systems. In these systems, the junction temperature is one of the important factors affecting the reliability of power MOSFET. In this article, an online power MOSFET junction temperature measurement is proposed considering storage charge during turn-off current fall process ( Q(fi)). First, as a temperature sensitive electrical parameter (TSEP), Q(fi) is discussed for feasibility. An online Q(fi) measurement based on the voltage generated by the parasitic inductance in the circuit (v(s-gnd)) is proposed and experimentally verified. Then, the advantages of Q(fi) as a TSEP are verified by experimental comparison with the other two TSEPs. Finally, the junction temperature online measurement demonstration system is established, and the online power MOSFET junction temperature measurement with Q(fi) is realized.