Improving Current Controllability in Bi-Mode Gate Commutated Thyristors

New Bi-Mode Gate-Commutated Thyristor Design Concept for High-Current Controllability and Low ON-State Voltage Drop

“…Controllable Current a number of two dimensional and three dimensional models have been proposed [6]- [9]. In this paper, the model developed for BGCTs in [6] is used which allows us to directly compare the new design with its state-of-the-art conventional counterpart.…”

“…In this paper, the model developed for BGCTs in [6] is used which allows us to directly compare the new design with its state-of-the-art conventional counterpart. It accounts for current redistribution in the wafer device during turn-off due to parasitic uneven gate inductive loading and it can successfully capture the turn-off failure in TCAD simulations which takes part due to uneven delay in the turn-off signal in different regions of the wafer.…”

“…An MCC test requires the facilitation of many turn-off simulations before a turn-off failure is recorded. The procedure followed and the conditions for considering a turn-off to be successful are described in [6]. The current level at the last successful (last pass) turn-off defines the Maximum Current Controllability.…”

“…The Bi-mode Gate Commutated Thyristor (BGCT) is a new reverse conducting device concept which has improved operation characteristics over the conventional Reverse Conducting Gate Commutated Thyristor (RC-GCT) [4]. The first experimental demonstration of this concept was presented in [5] whereas the requirements for high current controllability in Bi-mode GCTs were analysed in [6]. In this paper a new design is proposed which supersedes the conventional design optimization methodology for high Maximum Controllable Current (MCC), further improves the MCC and minimises the on-state losses.…”

“…II.NEW BGCT CELL DESIGN When compared to the conventionally optimised BGCT design [6] shown in Figure 1a, the new design depicted in Figure 1b, features the same diode and p-n-p Bipolar Junction Transistor (BJT) separation region, equal cell dimensions, cathode, anode and gate region area. The novelty lies in the cathode segment arrangement and cathode area distribution of the GCT part: in the new BGCT, the three full sized identical GCT cathode segments that are normally found in a 3:1 GCT:Diode BGCT are split in two full sized segments and two "less than full" (e.g.…”