Powerful stuff: World’s largest high-speed VFD

An 8 MW variable frequency drive operates with an output frequency of 500 Hz; it is claimed to be the world’s largest high-speed VFD.

08/28/2008


Atlanta, GA Siemens Energy & Automation says that its Siemens Robicon Perfect Harmony Drives have reached a technical milestone with the introduction of a 8 MW variable frequency drive (VFD) that operates with an output frequency of 500 Hz. The company claims it is the world’s largest high speed VFD.
The company says the drive’s power-cell-based multilevel arrangement provides a unique topology that allows operation up to 500 Hz, regardless of the VFD power rating. Tests on the VFD control were set to operate the motor in encoderless vector control with 920 Hz IGBT switching frequency, which is said to result in an effective switching frequency of 9.2 kHz and a sample frequency of 9.2 kHz. Tests reportedly demonstrated very high quality waveform to the motor with low harmonic distortion.
This latest VFD is intended to drive permanent-magnetic motors, the company says, such as those found in natural gas processing and transportation applications that require high-speed compression. Siemens claims it is one of the few companies to design a VFD that can operate with these physically smaller, more efficient permanent-magnetic motors.
C.G. Masi , senior editor
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