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Frequency converter SD4M for refrigeration and air conditioning technology

SIEB & MEYER: frequency converters for refrigeration and air conditioning applications

A flexible power control can significantly improve the efficiency of refrigeration and air conditioning applications. However, innovative refrigeration units with turbo or centrifugal compressors place high demands on the frequency converter technology. The high-speed specialist SIEB & MEYER based in Lueneburg (Germany) has the right solutions in the portfolio, which enable highly efficient applications with minimum rotor heating.


Frequency converters are not necessarily used in refrigeration units because many of these units operate with on/off mode and therefore do not require a power control. If the manufacturer decides on using the advantages of a flexible power control, frequency converters come into play. A power control via frequency converter has many advantages, for example, the efficiency of the unit can be significantly improved. In addition, users benefit from the very smooth running of the unit

Innovative refrigeration units with turbo or centrifugal compressors are increasingly in demand with higher prower ranges in this industry. These units operate with speeds of more than 100,000 rpm. Frequency converters by SIEB & MEYER easily provide the required speeds and their control method ensures an exceptionally low rotor heating. Furthermore, the devices can be adapted to changing requirements very well thanks to the flexibly configurable software

As with many high-speed applications, rotor heating is also a central issue in refrigeration units with turbo or centrifugal compressors. Therefore, power losses must be reduced as much as possible. SIEB & MEYER solves this issue with the 3-level output stage technology of the frequency converter series SD4M. Compared to the classic 2-level output stage, this technology is more complex, but it reduces the eddy-current losses in the rotor and as a result the motor heating to a minimum

"Thanks to our focus on the high-speed range, together with our customers we can offer solutions for the refrigeration and air conditioning technology with highest system efficiency," explained Torsten Blankenburg, CTO at SIEB & MEYER AG. "The SD2x and SD4x product families directly contribute to energy-efficient as well as cost-efficient applications with significantly increased overall efficiency."