A Pulsewidth Adjustable Trigger Method for Reverse Blocking Diode Thyristor to Suppress Current Filamentation and Improve di/dt Capability

In this article, to suppress the current filamentation and improve
di/dt
capability, a pulsewidth adjustable trigger method based on Marx generator for reverse blocking diode thyristor (RBDT) is proposed. The importance of trigger voltage pulsewidth for RBDT is first illustrated. The influence of the width of the voltage trigger pulse on RBDT is simulated in TCAD and verified by experiments. It is turned out that the turn-
on
delay time can be reduced when the width of voltage trigger pulse is shorter than 800 ns. When the width of the voltage trigger pulse further increases, the turn-
on
delay time becomes saturated. It is shown in the simulations that wider trigger voltage pulse can suppress the current filamentation in RBDT. The simulation result is validated by comparative experiments with two different widths of voltage trigger pulse generated by Marx generator at different main voltages. The switching loss of RBDT triggered by voltage pulsewidth of 1000 ns is smaller than that by voltage pulsewidth of 240 ns under the same condition. Besides, RBDT triggered by voltage pulsewidth of 1000 ns can even survive when the maximum
di/dt
per unit area is about 16.7 kA/
μ
s/cm
²
at the main voltage of 970 V. However, RBDT triggered by voltage pulsewidth of 240 ns fails at the main voltage of 920 V. Finally, the sensitivity of the proposed trigger method is verified.