5SHY3545L0014 3BHE023784R0001 ABB controllable rectifier electronic components

Special Features of Bi-Directional Control Thyristor (BCT) 5SHY3545L0014 3BHE023784R0001

1. Reverse Direction and Blocking Conditions:

• 5SHY3545L0014 3BHE023784R0001 does not have a unique reverse direction under the closed state blocking condition. The two voltage polarities correspond to the forward blocking state of either the A thyristor half or the B thyristor half.
• This impacts specification and parameter terminology, eliminating the need for an extra reverse blocking requirement found in standard Phase Controlled Thyristors (PCT).

2. Anode and Cathode Regions on Each Face:

• The BCT wafer features anode and cathode regions on each face.
• A and B thyristors are identified on the wafer by letters A, B on the central gate metallization.
  • Fig. 3.1 shows the central gate metallization indicating A and B on the BCT wafer.

3. Housing Design:

• BCT housings are designed to match the size of the standard PCT range.
• The cathode of the A thyristor-half faces the large flange side of the housing (similar to the cathode side of a standard PCT element).
• Cathode connections to the B thyristor-half are made through the wall of the ceramic nearest the unflanged side (similar to the anode side of a standard PCT element).
• Differently sized connectors to the A and B thyristor gate and cathode pairs prevent incorrect connections during installation and maintenance.
• Fixed current collectors and specially machined molybdenum discs allow accurate and reliable centering of the wafer sandwich in the housing without centering rings.
  • Outlines of the housing dimensions are given in the BCT product matrix (figure 2.1).

5SHY3545L0014 3BHE023784R0001 Surge Current Behavior:

• In a classical thyristor, the maximum allowable surge current depends on whether reverse or forward voltage is applied after the current transient.
• In a BCT, reverse voltage for the A thyristor is simultaneously forward voltage for the B thyristor.
• Surge current behavior varies based on whether the re-applied voltage is positive in the forward direction with respect to the conducting thyristor (case 1) or positive with respect to its counterpart, which was formerly not conducting (case 2).
• The BCT exhibits a unique situation in case 2, where the edge regions 1 and 2 close to the separation region are most sensitive. The mask layout is designed to strengthen the separation region, preventing failure in these sensitive areas.
  • Fig. 3.4 illustrates the surge current behavior of a BCT.

In summary, the BCT offers distinctive features, including the absence of a unique reverse direction, anode and cathode regions on each face, and a carefully designed housing. Its surge current behavior is unique in scenarios where a classical thyristor would experience reverse re-applied voltage, making the BCT well-suited for specific applications like Static Var Compensators (SVC). The mask layout is optimized to ensure robustness in sensitive regions during surge events.