Description; Working Principle - Siemens SICHARGE D Operating Instructions Manual
External load management system
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Also See for SICHARGE D:
- Operating instructions manual (147 pages) ,
- Product information (93 pages) ,
- Commissioning manual (30 pages)
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Description
2.1
Working Principle
The ELMS feature needs to be activated to start operation. The activation procedure shall be
explained in further sections. The processing on external specified power limit setpoint is done
by SICHARGE D charger and can be described as follows.
Sequence of operation
• The charger considers the actual states of the AC and DC charging outlets, dynamically
calculates and sends back to ELMS the minimum power limit that can be achieved
(G_Power_Min). If ELMS sends a limit below this value, it is neglected. The value is 1.5 kW if
no charging is active, and increases by 4 kW for each active charging port.
• The charger considers the maximum installed AC/DC-converters and the power limit
specified by the SICHARGE D configuration backend (Config_PowerLimit), and dynamically
calculates and sends back to ELMS the maximum power limit that is possible (G_Power_Max).
• It is expected that ELMS considers above two power limits and prepares the power limit
setpoint to be sent to charger accordingly (G_PowerLimit).
• The charger calculates the internal global power limit (GI_PowerLimit) based on
G_Power_Min, G_Power_Max, G_PowerLimit, Config_PowerLimit.
• The internal global power limit (GI_PowerLimit) is thereafter split by the charger into
permissible power limits for the AC and DC charging outlets.
• The distribution of power limits for individual DC charging outlets is decided by the charger
internally, based on the allocation of converter groups to that outlet.
• The derived internal power limits for each outlet are first sent to the connected EV and waits
until the EV communicates the new adjusted target current setpoints to the charger.
The charger reacts to the new EV target current setpoints by adjusting the setpoint to
converters participating in the charging sessions, thereby achieving the power limiting
function.
Note
It is important to consider the fact that the reduction of power from the charger in response to
the reduced power limit setpoint does not take place in the real time system as there are
communication and response delays from EV, and ramp down curves applied by EV or the
charger to adjust to new power limit setpoints, etc.
The ELMS therefore remains a near time system (not real time) in which instantaneous power
reduction or power increase may not always be possible with respect to external specified power
limit setpoints.
External Load Management System
Operating Manual, 07/2022, A5E52045935-AA
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