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