What are the advantages of cooling an IGBT with a cold plate?

IGBTs are considered the ideal switches today. They are used in a wide variety of industries. To ensure that they work effectively and have a long service life, cooling is crucial.

But what exactly is an IGBT? Why is a cold plate so well suited for cooling? And what is a cold plate anyway? We will answer these questions in this blog article.

What is an IGBT?


The IGBT has become the most widely used component in industrial applications. Today, it is the central element in converters for electrical drives of all kinds.

IGBT is the abbreviation for Insulated Gate Bipolar Transistor. It consists of three layers of differently doped silicon arranged in chips. These are arranged between two terminals, the collector-emitter and the gate-source path.

When control voltage is applied, these silicon layers become conductive. High currents and power can be switched with a very low control voltage.

As the name suggests, it is a combination of the following applications and combines their advantages:


MOSFET (=Insulated Gate)

  • Advantage: capacitive, almost powerless controllability
  • Control: controlled by   gate-source voltage


Bipolar Transistor (=Bipolar Transistor)

  • Advantage: high current carrying capacity and reverse voltage
  • Control: usually controlled by a base-emitter voltage


Typical applications

Due to its mode of operation, the IGBT is mainly used in power electronics. These include, among others:

  • Motor drives for industrial applications
  • Inverter in wind turbines
  • Converter stations in HVDC stations (transport of direct current over long distances, for example from wind farms in the North Sea to Southern Germany).
  • Traction converters in rail vehicles


IGBT power modules are at the heart of all these applications. Cooling plays an important role here everywhere. A cold plate is particularly well suited for cooling an IGBT.

What is a cold plate and how does it cool an IGBT?

A cold plate is a liquid cooler on top of which power electronics such as IGBT power modules are mounted. Inside the cold plate is a cooling structure (flow field) through which a cooling liquid flows (for example deionized water or a water/glycol mixture). 

The cold plate prevents an IGBT from exceeding the maximum temperature that would damage the electronics. This is made possible through the design of the cooling structure, which aligns with the power electronics. This circumstance has been comprehensively verified in simulations and proven by tests on the component at the power test station. This way, it improves the service life of the power electronics.

The connection technology vacuum brazing offers the highest degrees of freedom in the design of a cooling structure.

Why is a vacuum-brazed cold plate the ideal solution for cooling IGBTs?

The advantages can be directly derived from the requirements on the service life of the power electronics.

For optimum service life, an IGBT must not exceed certain temperatures. In this respect, the best possible cooling is a basic requirement for the stable and long functionality of an IGBT.

With lower chip temperature, the lifetime of the power module increases. By knowing the exact arrangement of the chips on the component surface of the IGBT, DAU can use thermal simulation to develop the ideal cooling concept with a cold plate - in combination with the advantages of vacuum soldering technology.

Prototypes are manufactured in-house at DAU and validated on the company's own IGBT test station. This provides customers with a picture of the entire thermal path - from the chip to the interface material to the cooler and into the cooling medium. The customer application is characterized under real conditions before the start of series production.

Conclusion: How is an IGBT optimally cooled?

IGBT modules can best be cooled with vacuum-soldered cold plates due to the high-performance requirements for cooling. The reason for this is the cooling structure, which is ideally designed for the chip layout.

This increases the service life and thus makes a valuable contribution to the stable functionality of the IGBTs.



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