Online Junction Temperature Extraction With Gate Voltage Under Nontrigger 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 nontrigger 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 nontrigger 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.