Power Electronics and Inverter Cooling Cooling Solutions -- DC Fans | Herays
Application Solution

Power Electronics and Inverter Cooling

Thermal management for heat sinks, power modules, and conversion equipment

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Problem Space

Industry Challenges

Understanding the specific thermal and environmental demands of Power Electronics and Inverter Cooling environments is the foundation of every Herays solution.

Power electronics — inverters, rectifiers, AC-DC converters, DC-DC modules, and motor drives — dissipate heat through IGBT modules, MOSFETs, diodes, inductors, and transformer cores. The challenge for cooling fan selection is that these heat loads are not constant: they vary with AC line conditions, load, ambient temperature, and the specific duty cycle of the application. A fan chosen for peak load conditions at 25°C may be dramatically oversized (and noisy) at partial load, or undersized when ambient temperatures reach summer maximums.

Key fan selection criteria for power electronics thermal management:

  • High static pressure capability — power converter heatsinks have closely-spaced fins that restrict airflow significantly. A fan delivering 150 CFM open-frame may provide only 80 CFM through a densely-finned heatsink. Always size fans from the system pressure-flow curve, not open-frame ratings.
  • 24V or 48V DC bus compatibility — 24V is most common for auxiliary power; 48V is increasingly standard in telecom and industrial UPS applications.
  • PWM speed control for variable load management — a converter at 30% load may only need 30–40% of peak airflow. PWM-controlled fans reduce noise, extend bearing life, and eliminate the thermal cycling stress that occurs when fans run at full speed in lightly-loaded conditions.
  • EMI considerations — switching noise from the fan drive circuit can couple into sensitive power converter measurement circuits. PWM fans with ferrite-suppressed or isolated drive stages are recommended in precision converter designs.
  • Ball bearings for vertical mounting and elevated ambient — power converters are often mounted vertically in racks. Sleeve-bearing fans have significantly reduced life at elevated temperatures in non-horizontal orientations.

Herays industrial axial fans are used in inverter and power converter cooling across industrial, telecom, and renewable energy applications. Available in 12V, 24V, and 48V with ball-bearing options across the range.

  • HR1225 24V — 120×120×25 mm, 134 CFM, 13.9 mmH₂O. The most common size for compact power converters in the 1–10 kW range with standard finned heatsinks.
  • HR1225 48V — same performance on a 48V auxiliary bus. Standard choice for telecom rectifiers and 48V-bus industrial UPS systems.
  • HR1238 24V — 120×120×38 mm, 186 CFM. The deeper frame provides 40% more airflow at equivalent noise, suited for high-power converters above 10 kW or compact enclosures with restricted airflow paths.

Tachometer output variants (−SF models) are available for all sizes and voltages, enabling the converter controller to detect fan failure and de-rate output power before thermal damage occurs — essential for any converter in unattended or remote installations.

How do I determine how much airflow my power converter needs? Start with the heatsink thermal resistance (°C/W) and the junction-to-case resistance of your switching devices. Work backwards from maximum allowable junction temperature to find the maximum allowable heatsink temperature, then calculate required airflow. Apply a 1.3× safety margin and derate by the actual system pressure drop.

Should I use PWM or analog fan speed control? PWM is strongly preferred. Analog voltage control (running the fan below rated voltage) reduces efficiency and risks startup failures at low temperatures. For any design where reliability matters, implement PWM control.

Blowing through or drawing through the heatsink? Both work. Drawing air through (fan on outlet side) allows cooler air to enter the heatsink first, which is thermally slightly better. A close-coupled fan-heatsink assembly without bypass air paths significantly outperforms one with large gaps between the fan frame and heatsink fins.

Contact Herays with your converter power dissipation, heatsink geometry, and bus voltage to get a fan recommendation and thermal management support.

Herays Approach

Our Solution

Precision-engineered DC fan technologies tailored to the performance and reliability requirements of Power Electronics and Inverter Cooling applications.

Why Herays

Key Features for Power Electronics and Inverter Cooling

Heat-sink cooling

Directed airflow across heat sinks, power boards, and conversion modules.

Performance matching

Selection by airflow, static pressure, voltage, speed, and acoustic target.

OEM-ready supply

Connector, wire, label, and batch production support for equipment manufacturers.

Application Engineering

Ready to find the right cooling solution for Power Electronics and Inverter Cooling?

Our application engineers are available to help you select the right product for your system requirements.

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