To main content

Offshore Power Electronics

New control systems

The objective has been to provide the required advanced control strategies for grid connected and islanding power electronics converters.

The task has been carried out as a combination of numeric simulations and laboratory demonstrations.

Summary of achievements

New control strategies

  • Defined a control strategy based on the concept of Virtual Synchronous Machine (VSM) for control of converters integrated in power systems with weak frequency regulation as:
    • Control of converters operating connected to grids benefiting from frequency support
    •  Control of converters operating in islanded grids with presence of synchronous generators
    • Control of converters operating in islanded grids dominated by power electronics with low or even zero physical inertia.
  • Validation of the VSM concept and of its implementation by numerical simulations and on an experimental setup
    • Simulations performed in the Matlab Simulink environment
    • Experimental tests executed on a 20 kW converter unit while control running on a OPAL-RT platform.

Implementation of converter control algorithms on a FPGA-based processor board

  • FPGA-based processor board
    • Xilinx Virtex5 FX 30 T
    • Embedded PowerPC440 core
    • 40 MHz ,  8 channel, 12 bit AD converter
    • 128 MB flash, 256 MB DRAM, 64k Eeprom
    • Interface for LEM current transducers
  • Designed for converter control in drives and grid connected configurations
    • Local user interface with display
    • CAN-communication for receiving operating modes and references
  • Operated as general purpose white-box converter controller in the lab

60 kVA laboratory converter modules

  • Developed in-house by support from OPE and other projects
  • Based on Semikron SEMIKUBE modules
  • 400 V, 100 A RMS ratings
  • LCL filter 500 µH, 50 F, 200 µH
  • Cabinet contains contactor, pre-charging circuit and discharge resistor
  • Internal rectifier to be used for motor drive demonstration
  • Prepared for operation in back-to-back or DC grid configurations

Converter control overview