Robicon Perfect Harmony 8 MW VFD

Siemens Energy & Automation says that its Robicon Perfect Harmony Drives have reached a technical milestone with the introduction of an 8 MW variable frequency drive (VFD) that operates with an output frequency of 500 Hz.

Siemens claims it is the world’s largest high speed VFD, and 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 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, the company says, to drive permanent-magnetic motors such as those found in natural gas processing and transportation applications that require high-speed compression.