The evolution of press-pack IGBTs marks a critical step forward in power electronics. Among them, press-pack IGBTs stand out for their ability to operate under extreme conditions such as HVDC transmission, renewable integration, and rail traction. Yet, traditional disc-type designs often face challenges—uneven pressure on chips, bulky structures, and limited current capability.
Moving beyond the limitations of traditional disc-type designs, the new square press-pack architecture delivers higher efficiency, improved thermal management, and enhanced reliability. As global industries accelerate electrification and renewable integration, these innovations provide the robust foundation needed for HVDC transmission, railway traction, and other demanding applications. This article explores the key technical advancements, market value, and real-world impact of next-generation square press-pack IGBTs.
Technical Advancements of Square Press-Pack IGBTs
A press-pack IGBT module, which includes a plurality of sub-modules that can move up and down relative to the tube shell Group, the sub-modules include:
- A conductive substrate 12 and a conductive cover plate 13, which can be accommodated in the tube shell or respectively extend out of the tube shell’s lower surface and upper surface;
- A plurality of chips 14 arranged side by side and spaced apart on the conductive substrate;
- A pressure-bearing member 11 that can be accommodated in the tube shell or extend out of the lower surface of the tube shell.
- A bypass busbar 15 is arranged above the chip, and its upper part is in contact with the upper surface of the pressure-bearing member.
- An elastic member 16 is arranged between the bypass busbar and the conductive cover plate.
Note: module outer frame 17; module cover 18; buffer block 19; conductive buffer block 20; gate output probe 21; side frame 22; pressure pad 23.
Uniform Chip Pressure
One of the most significant breakthroughs in the new square press-pack IGBT is the adoption of spring-based chip pressure control. Unlike conventional disc-type modules that rely heavily on external clamping mechanisms, each individual chip now experiences precisely regulated pressure through calibrated spring deformation. This innovation ensures a uniform distribution of mechanical stress across all chips, which in turn guarantees stable electrical contact. The result is not only improved reliability but also an extended operational lifetime, particularly important in applications where downtime is costly and repairs are challenging, such as HVDC stations or railway systems.
Multi-cell Modular Architecture
The square press-pack IGBT introduces a multi-cell modular structure, replacing the reliance on a single large chip. Instead, six or more square sub-modules are integrated in parallel, forming a scalable and highly flexible assembly. This architecture not only improves current-sharing capability but also makes it possible to design modules with tailored power ratings depending on system requirements. Engineers gain the freedom to scale up current capacity simply by adding more sub-modules, without fundamentally redesigning the device. This modularity also simplifies manufacturing and testing processes, further strengthening the reliability of the final product.
Enhanced Current Carrying Capability
Another crucial advancement lies in the use of fixed bypass busbars that remain unaffected by spring movement. This design ensures that current pathways are stable, minimizing resistive losses and electrical stress. Manufacturers can fine-tune busbar thickness and material composition to maximize conductivity, enabling the device to carry higher currents without overheating. The result is a significant leap in power-handling capability, which is particularly critical in grid-scale renewable energy systems and heavy industrial converters where large power throughput is a daily demand.
HIITIO Press Pack IGBT Products
Robust Thermal Management
Thermal stability has long been a weak point for high-power semiconductors, but the square press-pack IGBT addresses this with advanced substrate technology. By employing molybdenum (Mo) or molybdenum-copper (Mo-Cu) substrates bonded through soldering or silver sintering, the device achieves superior thermal conductivity and resistance to fatigue. These material choices ensure that the IGBT can endure rapid load cycling and harsh thermal environments without delamination or degradation. This advancement is crucial for applications such as offshore wind converters, smelting furnaces, and metro traction systems where constant thermal stress is unavoidable.
Note:
The thermal expansion coefficient of the conductive substrate 12 and the thermal expansion coefficient of the conductive buffer block 20 match the thermal expansion coefficient of the chip 14 (generally made of silicon material), thereby ensuring conductivity when the module is heated. The thermal expansion of the electrical substrate 12, the conductive buffer pad 20 and the chip 14 is consistent to avoid thermal expansion on their contact surfaces. Defects such as stress, cracks, or voids may occur.
Mechanical Safety and Reliability
The reinforced casing and composite structures of the new press-pack IGBT are specifically engineered to contain internal failures. In the rare event of a catastrophic breakdown, debris is contained within the package, preventing dangerous ejection that could harm surrounding components. This mechanical safeguard dramatically enhances system-level safety and is especially critical in high-stakes applications such as national grids, aerospace, and defense systems, where failure must not propagate beyond the device.
Note: When the module is subjected to pressure installation force “F”, the force decomposed into the interior of the module is divided into two parts. One is “F1”, which is the force received by the chip 14, and “F2”, which is the force received by the pressure-bearing injection molded part 11. “The acting force”. Among them, F1 is provided by the reaction elastic force generated by the deformation amount ΔH of the elastic member 16, that is, F1=k*△H, where k is the elastic coefficient of the elastic member 16, then F2=F-F1. That is, no matter how the pressing force F changes, the force F1 on the chip 14 is certain, which is only related to the elastic coefficient of the elastic component, and is not related to the pressing force F, thus ensuring the reliability of module application.
The Value of Innovation
These advancements represent more than just incremental improvements; they fundamentally change how press-pack IGBTs support modern energy systems:
- Higher Efficiency: Optimized current pathways and uniform chip stress reduce energy losses.
- Compact Power Density: Smaller module size allows integration into tighter system enclosures.
- Extended Service Life: Improved mechanical balance reduces chip fatigue, increasing reliability in 24/7 operations.
- Lower Maintenance: Modular structure simplifies testing and replacement, reducing downtime in critical systems.
- Future-ready Design: Scalable architecture allows easy adaptation for growing system demands without a full redesign.
Applications That Benefit Most
The new generation of press-pack IGBTs has broad applicability across industries that demand extreme durability and efficiency:
- High Voltage Direct Current (HVDC) Transmission
- Ensures stability in long-distance energy transfer.
- Provides high reliability for projects connecting offshore wind farms or cross-border energy trade.
- Railway Electrification and Metro Systems
- Withstands vibrations, shocks, and frequent load cycles.
- Delivers reliable traction power with minimized maintenance.
- Renewable Energy Integration
- Manages fluctuating loads from solar and wind power.
- Improves inverter and converter performance in grid-scale storage and hybrid plants.
- Industrial Power Conversion
- Provides robust switching in smelting, steel production, and heavy machinery.
- Ensures reliable operation in high-temperature, dusty, or corrosive environments.
- Aerospace and Defense Applications
- Critical for mission systems where failure is not an option.
- Offers mechanical robustness and fail-safe design under extreme stress.
Why This Matters for the Future
The move toward clean energy, smarter grids, and electrified transportation requires components that can handle unprecedented stress and power levels. The square press-pack IGBT is not just a refinement; it is a leap toward enabling these megatrends:
- Global decarbonization goals rely on HVDC projects that span continents.
- Urbanization demands reliable metro and railway infrastructure.
- Industrial automation requires semiconductors that thrive in rugged conditions.
With its scalable, safe, and efficient design, this technology becomes a cornerstone of tomorrow’s power infrastructure.
EXPLORE MORE HIITIO PRESS PACK IGBT
Partner with HIITIO for Advanced Press-pack IGBT Solutions
At HIITIO, we are redefining high-power semiconductor solutions with our square modular press-pack IGBT technology. Unlike traditional disc-type modules, our products feature multi-cell structures, consistent chip pressure, and superior current density. This ensures long-term reliability and compact integration for mission-critical systems. Whether for HVDC grids, renewable energy, rail transport, or heavy industry, HIITIO IGBTs deliver the durability and performance that engineers demand. Partner with HIITIO to power the future of energy with confidence.
