Application Unit (IAU) / Control Unit (ICU) storage control system and power plant controller

Country: Germany · Model: IAU / ICU

The Application Unit (IAU) and Control Unit (ICU) pair runs storage plants and includes a power plant controller certified to VDE-AR-N 4110 and 4120. The IAU is the central top-level controller, and the ICU sits between it and the inverters with their IBU battery units. Through it the storage takes commands from the grid operator, traders, PV and wind plants and external EMS.

Power plant controller: certified to VDE-AR-N 4110 and 4120
Protocols: Modbus TCP/IP, Modbus RTU, IEC 60870-5-101/104
Meters: up to 5
Modes: grid-parallel and grid-forming

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Technical specifications

More from the manufacturer’s documentation
Power plant controller	certified to VDE-AR-N 4110 and 4120
Protocols	Modbus TCP/IP, Modbus RTU, IEC 60870-5-101/104
Meters	up to 5
Modes	grid-parallel and grid-forming
Functions	FCR (built-in precision frequency measurement), peak shaving, spot and balancing markets
Installation	indoor and outdoor
Structure	4 modules: interface, application, grid compliance, system functions
ABC architecture	IAU (overarching control) — ICU (control unit for IBUs and inverters) — IBU (battery unit); IDG data gateway
Scaling	Up to 16 ICUs per IAU (24 ICUs planned), up to 4 BESUs per ICU, up to 64 BESUs per IAU
System example	4 BESUs of 8.1 MWh / 4.6 MVA each: 32.4 MWh / 18.4 MVA
ICU	Several IBUs and up to 4 inverters (DC strings); ModBUS interface to master BMS; power distribution between DC strings
IBU	1 battery bank of up to 8 racks
ICU power backup and climate	UPS, air conditioning for operation in nearly all ambient temperatures
Safety functions	External fire alarm connection with battery shutdown, cascaded connection during black start, charge/discharge derating
Grid topology	Ring, line or star
Control functions	Ramping, clustering, power distribution between AC strings
Grid connection	Per for new and existing plants; usable as overarching or downstream power plant controller
Integration	Generation plants (PV, wind, hydro), multiple traders, grid operators, reading of existing power plant controllers
Applications	Grid connection expansion, power procurement optimization, atypical/intensive grid usage, exchange trading, multi-market, backup power / island grid
Customs codes (for reference)
HS code	9032.89
UKTZED code (Ukraine)	9032890000
CN code (EU)	90328900

Specifications are taken from the manufacturer’s technical documentation. Updated 11/01/2026. Customs codes are for reference only; the final code is determined at customs declaration for the specific model.

Description

The IAU is built from 4 modules covering interface, application, grid compliance and system functions. Data runs over Modbus TCP/IP, Modbus RTU and IEC 60870-5-101/104, and up to 5 meters connect to the controller. Under its control the storage runs grid-parallel or grid-forming, including island operation for backup power. Built-in precision frequency measurement serves frequency containment reserve (FCR), and other tasks are peak shaving, ramping and trading on spot and balancing markets. The ICU splits power between the DC strings of up to 4 inverters and talks to the master BMS over ModBUS, while a UPS backs up its own supply. An external fire alarm signal shuts the batteries down, and in black start they connect in cascade. The network runs as a ring, line or star, and units go indoors or outdoors.

How to choose

Size the control system by the BESU count. One ICU handles up to 4 BESUs and one IAU up to 16 ICUs (24 planned), so up to 64 BESUs per site. For example, 4 BESUs of 8.1 MWh / 4.6 MVA give 32.4 MWh and 18.4 MVA under one IAU. With the cabinet-type scalepac one IAU runs 4–16 blocks of 254 kWh, and with the 4,600 kVA scalecube i3 and scalecube i4 grid blocks it adds telecontrol over IEC 60870-5-101/104.