Commutation overshoots based on a novel model for series thyristors during the turn‐off process

Abstract

The commutation overshoot is an important reference index for the insulation coordination of the converter station as well as the thyristor voltage capacity. Although the dispersity of reverse recovery charges of series thyristors may affect commutation overshoots, especially those at the thyristor level, little literature has tried to analyse it in detail. Firstly, this study compares the turn‐off models of independent thyristor and elaborates their applicability to series thyristors. Then, a novel model for series thyristors during the turn‐off process is proposed, based on which the turn‐off model of converter valve is also established. Subsequently, the validity and efficiency of the proposed model are discussed by simulations and it is applied to the analysis of commutation overshoots. The analysis shows that though the average model can be used to estimate the valve voltage stresses, it may lead to large errors in the thyristor voltage stress. And selecting the 1:n − 1 distribution as the distribution mode of reverse recovery charge in series thyristors will result in very conservative results.

Failure mechanisms of the thyristor switch in pulsed arc electrohydraulic discharges

“…Numerous studies [7,8] have demonstrated that the primary cause of thyristor damage in pulse power applications occurs during the reverse recovery process. Therefore, researchers concentrate on addressing voltage distribution problems that arise from reverse recovery [9]. The reverse recovery characteristics of thyristors can be simplified or equivalently transformed based on ideal components to a certain extent, such as the SPICE model [10] and the Hu-Ki model [11].…”

Development and Validation of a Smart Architecture for Thyristor Valves

“…The use of detailed models becomes even more important when the number of switching devices in series rises [7]. For example, a trigonometric exponential model has been extended to consider also the stray inductances in [8], showing how the solution helps to better predict current and overvoltage of the device.…”