4.6
Function Specification
This document only describes the Sytronix function that has been
integrated in DRn 5020 ASF. For information of basic converter
function, please reference EFC 5610 documents.
Pressure compensated variable displacement pumps (e.g., Rexroth A4, A10)
normally deliver a controlled pressure in a hydraulic system. A hydro-me‐
chanical pressure controller called a compensator (“DR“ or "DRG") is used to
adjust the pressure level of the pump output. The variable displacement
pump only delivers as much hydraulic fluid as required to maintain pressure.
If the system pressure rises above the pressure command value, pump dis‐
placement is reduced until the pressure falls back to the proper level. If the
system pressure falls, pump displacement is increased to raise the pressure
back up to the proper level again.
The “Sytronix-DRn“ functionality, is a control algorithm that modifies the
pump speed, as needed, as opposed to operating at a constant speed. Mod‐
el-based algorithms are used to optimize energy efficiency and greatly re‐
duce ambient noise. The DR/DRG pump compensator retains its function as
primary controller of system pressure.
To use "Sytronix-DRn", at least an actual pressure value, as well as a prefer‐
red swivel angle value for the relative pump volume have to be made availa‐
ble to the drive. As an option, the optimization of the internal models can be
improved by providing a pressure command value or an actual displacement
value.
The speed adaptation works independently of the pressure control that is still
carried out with the hydro mechanical DR/DRG controller. In particular, the
hydraulic circuit and the mechanical construction of the machine remain unaf‐
fected. Therefore, the "Sytronix-DRn" technology function is suited both for
upgrading existing installations within the scope of retrofit and for designing
new machine generations.
"Sytronix-DRn" has been designed for pressure control systems. In combina‐
tion with remotely operated pressure control (Rexroth DRG) or pressure and
flow control (Rexroth DFR), it is necessary to check whether the technology
function is suited or not in individual cases.
The product provides the following features.
●
Speed adaption of pressure controlled DR/DRG pumps to improve ener‐
gy efficiency and noise emission
●
Automatic boost function to reduce pressure drops in load switching
conditions
●
Automatic motor derating to ensure cooling power on lower motor
speeds
●
Speed masking to avoid defined speed ranges to improve noise emis‐
sion
●
Auxiliary pumps for oil cooling or filtering can be handled by "Sytronix-
DRn"
●
Protection functions
–
Detection of pressure drops
–
Soft start of electric drive
–
Actual pressure monitoring
–
Limiting maximum pump speed
DOK-SYTROX-DRN5020****-IT05-EN-P
Bosch Rexroth AG
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Frequency-Controlled Pump Drive System Sytronix DRn 5020
About This Product
