Description of the system

The iGCU is a central interface for connecting various power supply systems to higher-level networks (e.g., European grid, microgrids, generators).

Main function: seamless transition between On-Grid and Off-Grid operation.

Advantage over traditional STS systems: no voltage interruption during switching, thanks to intelligent component control.

The iGCU consists of: 

• DDI (grid coupling switch)
• SPI (grid protection relay)
  
• Synch (synchronization relay)
• PCS (inverter with various operating modes)
• BATT/PV (battery or PV system)
  
• UMG (unit for measuring grid parameters)
  
• iGCU control unit (regulation and switching control)
  

Visualization of system connection

• The DDI connects the local grid to the upper-level grid
  
• The SPI detects grid faults and disconnects the system
  
• The Synch synchronizes voltage/frequency for reconnection
  
• The PCS dynamically adjusts the operating mode (On/Off-Grid)
  
• The iGCU coordinates all components fully automatically                                                      
  

iGCU in off-grid/microgrid mode

• DDI is open
• PCS operates in grid-forming mode, stabilizing voltage and frequency
• Two active PID controllers (for voltage and frequency), including drooping function 
•  Synchronization capability remains available

Transition on-grid→ off-grid

• Transition can be planned or automatic (due to grid fault)
  
• SPI detects the fault or receives a manual disconnection comman
  
• iGCU automatically switches PCS to island mode without interruption                           

Transition off-grid→ on-grid

• SPI detects grid availability
  

• iGCU adjusts voltage/frequency via PCS and activates Synch
  

• After successful synchronization, DDI closes and system returns to On-Grid mode
  

• Various parameters can be configured (e.g., frequency deviation, voltage limits, PID settings)