Which cooling methods are used in power electronics?


Maintaining optimal temperature levels in a power supply system is a paramount priority for power designers, ensuring unparalleled performance and utmost safety. Premium PSU understands the criticality of efficient cooling in power supplies and has developed advanced cooling techniques to address this challenge. Thermal management is part of the design process. In this article, we will explore two cooling methods employed by Premium PSU: liquid cooling and conduction cooling.

Cooling techniques for power supply units

Efficient cooling in an industrial environment will be required to guarantee the internal temperature of the module does not exceed the safety limit; but in extreme conditions, reliability is extremely important not to have failure risk.

Our products can be configured with different options in the cooling system: fan or fan redundancy, convection, conduction, and liquid cooling. Let’s talk about the last ones. Some applications need to guarantee efficient cooling, so the importance of conduction cooling and efficient thermal management is key to the engineering design. The power electronics engineers have been improving the product’s efficiency.

Liquid Cooling and Conduction Cooling: A Dynamic Duo

Premium PSU’s liquid cooling system combines conduction cooling with a cooling plate to effectively dissipate heat generated by the PSU components. This hybrid approach maximizes cooling efficiency and helps maintain stable operating temperatures.

Cooling Plate & Ambient Temperatures: Factors to Consider

When deciding on the appropriate cooling method, it is essential to consider the relationship between the cooling plate and ambient temperatures. Liquid or conduction cooling methods create a cold internal ambient within the PSU, which surely impact the performance and lifespan of certain components.

While power components can withstand high temperatures, other sensitive components such as analog circuits, digital circuits, electrolytic capacitors, and optocouplers may be adversely affected. For this reason, it is recommended to combine liquid cooling with forced air when the external ambient temperature is lower than the liquid cooling system. This approach effectively reduces the internal temperature, thereby enhancing Mean Time Between Failures (MTBF) and overall product lifespan.

How to conduct the heat to the cooling plate?

To ensure efficient heat transfer to the cooling plate, there are various techniques:

  • Conduction-Cooled Power Components: Premium PSU prioritizes the use of conduction-cooled power components whenever possible. These specialized components are designed to facilitate effective heat transfer, enhancing the overall cooling performance of the PSU.
  • Design Considerations for Conduction Cooling: Premium PSU’s design team incorporates conduction cooling principles into their projects. This includes optimizing the layout and arrangement of inductive power components to enhance heat dissipation.
  • Potting: Potting, a technique where a protective resin is applied, helps enhance heat conduction by minimizing air gaps and increasing the surface area available for heat transfer within the PSU.
  • Gap Fillers: Premium PSU utilizes high-quality thermal interface materials, such as gap fillers, to promote efficient heat conduction from the printed circuit board (PCB) to the cooling plate. These materials bridge the gaps and facilitate the transfer of heat, ensuring effective cooling throughout the PSU.

Thermal Analysis and Simulations: Premium PSU’s Expertise

Premium PSU boasts a dedicated team at their Research, Development, and Innovation (RDI) facility, equipped with the necessary tools and expertise to optimize thermal designs. Leveraging advanced software such as FloEFD, seamlessly integrated with the mechanical 3D design software Solid Edge by SIEMENS, Premium PSU conducts accurate and efficient fluid flow and heat transfer simulations. These simulations enable them to identify potential thermal challenges and develop effective cooling solutions for each project.


Fourier’s Law

Fourier’s law is a fundamental principle in thermal physics that describes the transfer of heat through a material. It states that the rate of heat transfer through a material is proportional to the negative gradient in temperature and to the area across which heat is being transferred. This law is of great importance for thermal efficiency in various applications, including power electronics. Here are a few reasons why Fourier’s law is significant:

  1. Understanding Heat Transfer: Fourier’s law provides a mathematical framework to understand how heat moves from a region of higher temperature to a region of lower temperature. It helps engineers and designers analyze and predict the behavior of heat transfer in different materials and systems.
  2. Thermal Management: In power electronics, efficient thermal management is crucial to maintain the components within safe operating temperatures. Fourier’s law helps in determining the rate of heat dissipation and designing cooling systems that can effectively remove excess heat from sensitive components.
  3. Optimizing Cooling Solutions: By understanding Fourier’s law, engineers can optimize the design of cooling systems to enhance thermal efficiency. They can analyze factors such as surface area, material conductivity, and temperature gradients to determine the most effective cooling methods, such as convection, conduction, or liquid cooling.
  4. Component Reliability: Excessive heat can lead to accelerated aging and degradation of electronic components, reducing their reliability and lifespan. Fourier’s law aids in assessing temperature distributions and designing cooling solutions that minimize hotspots and maintain uniform temperatures, thereby improving the reliability and longevity of power electronic systems.
  5. Energy Efficiency: Efficient thermal management based on Fourier’s law can contribute to energy savings. By effectively dissipating heat and preventing overheating, power electronic systems can operate more.

These points are apreciated in the equation. It is important because let us know that the total heat transferred will always depend to the material conductivity, the temperature gradient and also the areas in contact. That’s why the heatsinks have fins to increase the surface area.

To better understand the thermal conductivity, here some examples:

  • Diamond: 1000 W/mK
  • Aluminum : 237 W m−1 K−1
  • Fiberglass (0.04 W/mK): Insulating material

On the other hand, the temperature gradient indicates the heat difference between critical components (transistors, transformers, inductors, etc.) and the ambient temperature. efficiently, reducing energy consumption and minimizing waste.

In summary, Fourier’s law is important for thermal efficiency as it enables engineers to understand and optimize heat transfer processes, design effective cooling solutions, enhance component reliability, and improve energy efficiency in power electronics and other applications.

Premium PSU’s commitment to innovative cooling solution by leveraging liquid cooling with conduction cooling and employing techniques such as conduction-cooled power components, potting, and gap fillers, ensuring efficient heat dissipation and extends the lifespan of their products. With its dedicated RDI team equipped with advanced thermal analysis and simulation tools, Premium PSU continues to deliver high-performance PSUs that meet the demanding cooling requirements of power electronics.