5SHX1960L0006 3BHB016120R0002 ABB excitation control module

5SHX1960L0006 3BHB016120R0002 ABB excitation control module

Mechanical Data: Mounting Force (Fm):

Definition:

• Fm is the mounting force required to establish proper electrical and thermal contact in the IGCT assembly.

Importance:

• Crucial to ensure Fm stays within specified limits even under limiting operating temperatures.
• Considers thermal expansions and tolerances of stack parts in the clamping system design.

Consequences of Too Low Mounting Force:

1. Increased Thermal Resistance:
   • Low mounting force results in increased thermal resistance.
   • Particularly problematic at high currents, leading to damage to dry interfaces within the housing, potentially causing degradation.
2. Incomplete Contact with Cathode Segments:
   • Individual cathode segments may not all be correctly contacted.
   • Results in increased VT (threshold voltage) and drastic reduction of ITSM (surge current) and ITGQM (RMS on-state current).

Consequences of Exceeding Mounting Force:

1. Increased Mechanical Stress on Silicon Wafer:
   • Exceeding Fm leads to increased mechanical stress on the silicon wafer, especially under severe thermal cycling.
   • Reduces the life expectancy of the device and can lead to premature wear-out of the cathode segment metallization, causing gate-to-cathode short circuits.
2. Deformation of Copper Pole Pieces:
   • Uneven pressure distribution may cause the copper pole pieces of the housing to deform plastically.
   • This deformation can result in localized mechanical stress on the silicon wafer, leading to degradation of device performance or even wafer fracturing.

Homogeneous Pressure Distribution:

• It is vital that the pressure is distributed homogeneously over the contact area to avoid deformation issues.
• Details on a correct clamping system are described in Application Note 5SYA2036 “Recommendations regarding mechanical clamping of Press Pack High Power Semiconductors.”

Minimum Clamping Force:

• For basic device verifications (blocking or gating checks), a minimum clamping force of about 1 kN is required to establish contact for low-current measurements.

Understanding and maintaining the correct mounting force is crucial for ensuring the reliable operation and longevity of IGCT devices. Proper clamping system design and adherence to recommended guidelines are essential for optimal performance.