Use Cases
1. USE-CASE N°1: MVDC PV FARM
The MVDC PV Farm use case consists of 10 MW building blocks. Each building block is composed of four solid-state transformers allowing the voltage increase from low to medium voltage. The low voltage side is connected to a PV array.
The building blocks are arranged in such a way to form a 240 MW PV farm. This can then be multiplied in order to reach higher power levels.
A battery is added to the medium voltage bus, via an DC/DC converter.
The PV farm use-case is in a star topology configuration.
Main technical specifications
Four solid-state transformers of 2.5 MW form a 10 MW building block. The low voltage side of each solid-state transformer is connected to a PV array of 150 strings, with 27 panels per string. The inter-array voltage, on the medium voltage DC side, is in the range of ±20 to ±60 kV.
How will it be tested?
At the submodule scale, the SiC based submodule will be tested on an actual test bench in a modular multilevel converter topology configuration in an as representative as possible mission profile regarding the multilevel DC/DC converter.
At other scales, power conversion chain and PV farm, it will be tested through simulations.
Project’s focus
The project focuses on 3 different scales:
Submodule: SiC based submodule for innovative multilevel DC/DC converter topology applications,
Power conversion: innovative multilevel DC/DC converter
PV farm: MVDC inter-array system and its connection to the power grid at the point of common coupling.
USE-CASE N°2: FIRST DC ALTERNATIVE WIND TURBINE – MMC-DRU CONCEPT
This use case considers a wind turbine allowing to address the possibility of reaching the highest possible DC voltage, typically in the range of 80 to 160 kV.
For this, a rectifier allowing the compactness is needed, so the choice of using a Si-based diode rectifier unit is made. For the AC/AC converter, with inputs and outputs in medium voltage range, the converter topology is a SiC-based back-to-back modular multilevel converter.
Main technical specifications
We consider a wind turbine of 20 MW.
The generator output is assumed to be 6.6 kV. The same range is supposed for the modular multilevel converter output.
The diode rectifier unit input is assumed to be at 30 to 100 kV, while the DC output is in the range of ±40 to ±160 kV.
How will it be tested?
At submodule scale, the SiC-based submodule will be tested on an actual test bench in a modular multilevel converter topology configuration with a representative mission profile.
At the other scales, power conversion chain and wind farm scales, it will be tested through digital twin simulations, based on digital twin modelling of the SiC-based modules.
Project’s focus
The project focuses on 3 different scales:
• Submodule: SiC-based power module for back-to-back modular multilevel converter converter topology
• Wind turbine power conversion: Back-to-back modular multilevel converter, medium frequency step-up transformer and passive diode rectifier, wind turbine generation mission profile
• Wind farm scale: Wind farm DC inter-array system and its connection to the power grid at the point of common coupling
3. USE-CASE N°3: 2ND DC ALTERNATIVE WIND TURBINE – DC/DC MULTILEVEL CONVERTER
This use case considers a wind turbine with a more classical converter technologies and compatible with the space constraints. For the DC/DC converter, whose input is low voltage range and output is medium voltage range, the converter topology will a solid-state transformer in a multilevel configuration.
Main technical specifications
We consider a wind turbine of 20 MW.
The generator output is in the low voltage range. The rectifier outputs the low voltage as well.
The SiC-based solid-state transformer allows the DC voltage increase from low to medium voltage, in the range of ±40 to ±80 kV.
How will it be tested?
The SiC based solid-state transformer will be simulated with real-life data in an as representative as possible mission profile with regard to the multilevel DC/DC converter for the submodule scale, and through simulations for the other scales
Project’s focus
The project focuses on 3 different scales:
• Submodule scale: SiC based submodule in for innovative multilevel DC/DC converter topology applications.
• Wind turbine power conversion scale: Innovative DC/DC converter (solid-state transformer including medium frequency transformers), wind turbine low voltage rectifier, wind turbine generation mission profile
• Wind farm scale: Wind farm DC inter-array system and its connection to the power grid at the point of common coupling
