Online Junction Temperature Extraction with Gate Voltage under Non-trigger Current for High-Voltage Thyristor

This letter proposes a junction temperature (T_{j}) extraction method for the high-voltage thyristors with the cathode short-circuiting structure. It has been studied that the gate voltage V_{gk} under non-trigger current is a practical temperature-sensitive electrical parameter (TSEP), which can be used for online T_{j} monitoring by calibrating the linear relationship between the gate voltage V_{gk} under non-trigger current and T_{j} effect. The proposed TSEP does not affect the operating state of the thyristor and is suitable for complex operating conditions since it is extracted during OFF state. The total error in the T_{j} estimate obtained from the proposed TSEP is verified within ±2 °C by comparing with the T_{j} obtained from the traditional gate voltage V_{GK} based TSEP during ON state.