Siemens SINAMICS Perfect Harmony drives feature 50+ proven technologies designed to provide a reliable solution for critical applications. The medium-voltage power output of the VFD drive system is created by linking a series of low-voltage power cells, offering a scalable solution for a wide range of voltage and output power – from 2.4–7.2 kV.
This modular design also facilitates the drive’s most innovative feature, Advanced Cell Bypass, which allows the drive to maintain consistent output if one or more cells fail. In the event of a fault, the drive isolates the output of the failed cell and reconfigures the power section to bypass the cell without interrupting performance – all in less than a quarter of a second. The quality of the voltage waveform remains virtually unchanged even when only a single cell per phase remains operational.
Perfect Harmony’s power conversion efficiency is in a class by itself, notes the company. An integral transformer with phase-shifted secondaries provides 18-pulse or better input harmonic cancellation, allowing the medium voltage drive to exceed .95 power factor at even the lowest normal operating speeds. The quality of the output voltage is so close to perfect sine-wave shape that motors of any type – old or new, low-speed or high-speed – can be operated without any additional stress.
Synchronous transfer provides a bumpless transition when starting a series of multiple motors, pumps or compressors and transferring them across the line. Issues related to dU/dt, startup damage, power grid stress, overheating and increased torsion vibrations are no longer a concern. The result is decreased downtime, improved energy efficiency and limited wear and tear.
The optional process-tolerant protection system (ProToPS) in combination with cell bypass supports the high reliability and availability of the SINAMICS Perfect Harmony GH180. Instead of tripping the drive and automatically shutting down the system due to a malfunction, ProToPS provides a hierarchical system of warnings. This control strategy allows time to evaluate the situation and respond appropriately to avoid a system shutdown.
Customer benefits include: very small footprint; no harmonic line filters or power factor compensation required; no significant drive-induced torque pulsations – even at low speeds; no need for expensive flexible couplings; and no cable length restrictions.
Siemens, www.industry.usa.siemens.com
