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Three-level Technology for Minimal Losses and Increased Efficiency

Press releases

Multilevel frequency converter SD4M by SIEB & MEYER

For the development of SD4M, SIEB & MEYER combined tried and tested technology with the latest control and communication technology. Equipped with innovative three-level technology, the compact frequency converter is not only ideal for high-speed turbomachinery but also of great appeal for high-performance HSC routing machines that are frequently used, for example, in the aerospace industry. In these applications, SD4M ensures minimal motor losses and therefore high efficiency. 


The SD4M variants in the range from 70 to 490 kW or 120 to 800 A rated current correspond to their SD2M counterparts in terms of power electronics. With the new performance class of 70 kW and 120 A, SD4M expands the current performance spectrum of SD2S and SD4S, closing the gap in the frequency converter portfolio of SIEB & MEYER. The multiprotocol real-time Ethernet interface, available on the device as standard (including PROFINET IO and EtherCAT), enables hassle-free implementation of the SD4M in the higher-ranking control. An optimal operation with an external regenerative power supply is possible using the variants with DC supply

The innovative three-level technology of SD4M combined with device-dependent switching frequencies of up to 32 kHz ensure excellent current quality, which reduces motor losses and increases the overall efficiency accordingly. This prevents excessive rotor heating without expensive motor chokes or sine-wave filters. In addition, the three-level technology reduces the load on the motor insulation

Optionally, the SD4M comes with features for optimized operation of turbo compressors and blowers. Active magnetic bearings, for example, can be supplied with the required DC voltage via clamp connections – this voltage is maintained for braking in the event of malfunctions. Another highlight in the SD4M performance spectrum is the new dynamic control of IPM motors, which offers customers further degrees of freedom when it comes to the system conception

Beside water-cooled SD4M variants, air-cooled devices are also available on request. SIEB & MEYER has applied for NRTL/CSA certification for all device variants so that users can soon integrate the devices into machines for the US market without additional approvals.