Online High-Power p-i-n Diode Junction Temperature Extraction With Reverse Recovery Fall Storage Charge

This paper proposes a method to extract the junction temperature of high-voltage and high-power p-i-n diodes. It is investigated that the swept-out charge during reverse recovery current fall time is affected by junction temperature variation, which makes the swept-out charge a possible thermo-sensitive electrical parameter (TSEP). Thanks to the specific package of high-power IGBT modules with p-i-n diodes, the swept-out charge of a p-i-n diode can be measured by the induced voltage $v_{{eE}}$ on the parasitic inductor $L_{{eE}}$ between Kelvin and power emitter terminals. In typical inductive half-bridge circuit, the comprehensive analysis of commutation between the upper p-i-n diode and lower enabled IGBT discloses the monotonic relationship among the reverse recovery charge, reverse current fall time, and junction temperature. A double pulse chopper circuit is used to validate the theoretical analysis. The experimental results show that the dependence between diode junction temperature and charge during the reverse recovery current fall time is approximately linear. A three-dimensional lookup table is calibrated and can be used to estimate the p-i-n diode junction operating temperature. Finally, an experimental comparison of four TSEPs for p-i-n diode is presented to verify the feasibility of the implementation of proposed TSEP.