Periodic Reporting for period 4 - HVDCGEN (High Speed HVDC Generator / Motor)
Période du rapport: 2021-09-01 au 2022-08-31
- Problem Addressed, Importance for Society, and Overall Objectives -
Existing aircraft architectures make use of a 115/230V electrical network for their onboard power demands. Power is distributed around the aircraft by cables which, with increasing electrical energy demands, are large and of significant weight. New aircraft architectures such as the Next Generation Civil Tilt Rotor (NextGENCTR) concept will include increased numbers of electrical systems with increased power demands. To minimise cable and generator weight there is a requirement for a High Voltage network, to be provided and controlled by a high efficiency, High Voltage DC generator and control unit.
By developing a high speed HVDC generator/motor Denis Ferranti will address safety concerns, reduce aircraft mass, facilitate more electric systems, and improve efficiency. These impacts are key enablers ensuring the NextGENCTR can meet the goals of ACARE, horizon 2020, and flightpath 2050 by reducing fuel consumption, CO2 and NOx, while simultaneously strengthening industrial competitiveness in the EU aeronautical industry.
In the framework of Clean Sky 2 the call objective is to provide innovative engineering solutions for the NextGENCTR demonstrator HVDC generator/motor by designing, developing and manufacturing a new generator/motor.
Specific project objectives and respective results are shown in the following paragraphs.
Existing aircraft architectures make use of a 115/230V electrical network for their onboard power demands. Power is distributed around the aircraft by cables which, with increasing electrical energy demands, are large and of significant weight. New aircraft architectures such as the Next Generation Civil Tilt Rotor (NextGENCTR) concept will include increased numbers of electrical systems with increased power demands. To minimise cable and generator weight there is a requirement for a High Voltage network, to be provided and controlled by a high efficiency, High Voltage DC generator and control unit.
By developing a high speed HVDC generator/motor Denis Ferranti will address safety concerns, reduce aircraft mass, facilitate more electric systems, and improve efficiency. These impacts are key enablers ensuring the NextGENCTR can meet the goals of ACARE, horizon 2020, and flightpath 2050 by reducing fuel consumption, CO2 and NOx, while simultaneously strengthening industrial competitiveness in the EU aeronautical industry.
In the framework of Clean Sky 2 the call objective is to provide innovative engineering solutions for the NextGENCTR demonstrator HVDC generator/motor by designing, developing and manufacturing a new generator/motor.
Specific project objectives and respective results are shown in the following paragraphs.
- Requirement Definition and Design -
A collaboratively defined requirement set for the electric machine and power electronics intended for the NextGENCTR application was performed in the early stage of the HVDCGEN project. This activity provided functional and constraint requirements which formed the baseline for the justification work developed throughout the project to demonstrate system compliance.
The design phases of the project consisted of extensive trades covering the following main topics:
• Electric Machine Trade Study - focusing on machine topology, pole/slot combination, materials, winding configuration, and geometry
• Mechanical Design Study - focussing on housing construction, interfaces, cooling, and mechanical disconnection options
• Power Electronics Design Study - focussing on monitoring and protection, control system, signal I/O, interfaces, cooling
The end result was a design definition and associated documentation to allow for the manufacture of:
A state-of-the-art electric machine consisting of:
• Laminations: NO10
• Windings: Distributed round wire, 200°C rated
• Rotor: Surface mount magnets with carbon fibre wrap
• Speed: 24,000rpm
• Power: 95kW continuous
• Cooling: Air cooled from shaft mounted mixed flow fan
• Mechanical disconnection: Pneumatic shaft retraction
A bespoke power electronics and control system consisting of:
• Architecture: Three SiC MOSFET Inverter
• Safety: Dual controller architecture with monitoring & protection and dedicated power controller
• Cooling: Air cooled heat sink
• PCBs: Power board, control board, gate driver boards
- Testing and High-level Results -
Two HVDCGEN prototypes have been manufactured (motor and GCU electronics). An extensive testing campaign has been performed on these prototypes using a ‘back-to-back’ motor/generator test arrangement.
Summary of the project objectives and results achieved:
• Provision of power: 90kW. 270VDC Voltage: ± 1%, Current ripple: ± 5A. EN 2282 and/or Mil standard 704F - Partially achieved: Uncontrolled generator output approx. 80kW, with control system tuning controlled generation would be achieved.
• Safety objectives met for CAT events < 1 x 10^-10/FH - Achieved: Justification by analysis, implemented in the architecture and tested successfully mechanical/electrical disconnect, dedicated monitoring and protection controller.
• Efficiency > 90% - Partially achieved: Approx. 88% in motor mode / 92% in generator mode (uncontrolled operation). Expected that with minor control system tuning higher efficiency could be achieved.
• Reduced mass: < 23 kg - Not achieved: System mass 31.4kg – with further optimisation 23kg is believed to be achievable but would come with significant cost impact.
• Easier maintainability: LRU < 16kg. Change out times < 1 hour - Achieved: Motor/Generator 15.8kg and GCU 15.6kg.
• Provide mechanical power 5 kW - Achieved: Mechanical power up to 90kW achieved.
- Communication and Dissemination, Exploitation, IP -
When possible, opportunities to publicly highlight the success of the HVDCGEN project have been taken. The HVDCGEN motor/generator was displayed in Cardiff in Oct 2021 at the Autolink conference, an initiative arranged by the Welsh Automotive Forum. Feedback from this event was very positive.
Exploitation and lessons learnt from the HVDCGEN project has been initiated. Initial discussions with a EU helicopter manufacturer closely linked with the HVDCGEN project on how the outputs of project (technology and knowledge gained), or other DFG technology and capabilities, may fit with their electrification/hybridisation strategies have been very positive. Further discussions and provisional planning for a future site-visit to explore relevant topics is ongoing. Globally the drive for electrification/hybridisation of VTOL, rotary, and fixed wing aircraft is increasing - these future vehicles/platforms may be potential opportunities to exploit the HVDCGEN technology. Attracting interest will be achieved through attendance at high profile conferences/events, new funded project sources (e.g. EU Clean Aviation), or directly through OEMs.
Three main areas of the HVDCGEN project have been identified as having potentially valuable IP:
• System air cooling architecture
• Mechanical disconnection system
• Power electronics architecture and hardware protection
A collaboratively defined requirement set for the electric machine and power electronics intended for the NextGENCTR application was performed in the early stage of the HVDCGEN project. This activity provided functional and constraint requirements which formed the baseline for the justification work developed throughout the project to demonstrate system compliance.
The design phases of the project consisted of extensive trades covering the following main topics:
• Electric Machine Trade Study - focusing on machine topology, pole/slot combination, materials, winding configuration, and geometry
• Mechanical Design Study - focussing on housing construction, interfaces, cooling, and mechanical disconnection options
• Power Electronics Design Study - focussing on monitoring and protection, control system, signal I/O, interfaces, cooling
The end result was a design definition and associated documentation to allow for the manufacture of:
A state-of-the-art electric machine consisting of:
• Laminations: NO10
• Windings: Distributed round wire, 200°C rated
• Rotor: Surface mount magnets with carbon fibre wrap
• Speed: 24,000rpm
• Power: 95kW continuous
• Cooling: Air cooled from shaft mounted mixed flow fan
• Mechanical disconnection: Pneumatic shaft retraction
A bespoke power electronics and control system consisting of:
• Architecture: Three SiC MOSFET Inverter
• Safety: Dual controller architecture with monitoring & protection and dedicated power controller
• Cooling: Air cooled heat sink
• PCBs: Power board, control board, gate driver boards
- Testing and High-level Results -
Two HVDCGEN prototypes have been manufactured (motor and GCU electronics). An extensive testing campaign has been performed on these prototypes using a ‘back-to-back’ motor/generator test arrangement.
Summary of the project objectives and results achieved:
• Provision of power: 90kW. 270VDC Voltage: ± 1%, Current ripple: ± 5A. EN 2282 and/or Mil standard 704F - Partially achieved: Uncontrolled generator output approx. 80kW, with control system tuning controlled generation would be achieved.
• Safety objectives met for CAT events < 1 x 10^-10/FH - Achieved: Justification by analysis, implemented in the architecture and tested successfully mechanical/electrical disconnect, dedicated monitoring and protection controller.
• Efficiency > 90% - Partially achieved: Approx. 88% in motor mode / 92% in generator mode (uncontrolled operation). Expected that with minor control system tuning higher efficiency could be achieved.
• Reduced mass: < 23 kg - Not achieved: System mass 31.4kg – with further optimisation 23kg is believed to be achievable but would come with significant cost impact.
• Easier maintainability: LRU < 16kg. Change out times < 1 hour - Achieved: Motor/Generator 15.8kg and GCU 15.6kg.
• Provide mechanical power 5 kW - Achieved: Mechanical power up to 90kW achieved.
- Communication and Dissemination, Exploitation, IP -
When possible, opportunities to publicly highlight the success of the HVDCGEN project have been taken. The HVDCGEN motor/generator was displayed in Cardiff in Oct 2021 at the Autolink conference, an initiative arranged by the Welsh Automotive Forum. Feedback from this event was very positive.
Exploitation and lessons learnt from the HVDCGEN project has been initiated. Initial discussions with a EU helicopter manufacturer closely linked with the HVDCGEN project on how the outputs of project (technology and knowledge gained), or other DFG technology and capabilities, may fit with their electrification/hybridisation strategies have been very positive. Further discussions and provisional planning for a future site-visit to explore relevant topics is ongoing. Globally the drive for electrification/hybridisation of VTOL, rotary, and fixed wing aircraft is increasing - these future vehicles/platforms may be potential opportunities to exploit the HVDCGEN technology. Attracting interest will be achieved through attendance at high profile conferences/events, new funded project sources (e.g. EU Clean Aviation), or directly through OEMs.
Three main areas of the HVDCGEN project have been identified as having potentially valuable IP:
• System air cooling architecture
• Mechanical disconnection system
• Power electronics architecture and hardware protection
- Key Innovations, Main Results, and Potential Impacts -
The key innovations associated are:
• Given the demanding safety requirements and the use of permanent magnet technology, an innovative clutch/mechanical disconnection has been developed which is the subject of a patent application. This facilitates the use of permanent magnet technology and mitigates the risk of fire in the event of a short circuit
• The cooling strategy adopted for the system is novel and includes series air cooling of the electric machine and power electronics, where the airflow is self-extracted by the electric machine. This architecture has benefits over liquid cooling in overall simplicity, inherent reliability, and also reduces the balance of plant of a comparable liquid cooling solution
• The 3-level power electronics system which include dedicated DAL B power controller, DAL A monitoring and protection controller, and isolating contactors
The main results achieved were:
• Development milestones and justification work completed
• Prototypes manufactured to design definition
• Successful test of:
1. System in generator mode (limited)
2. Electrical disconnection
3. Mechanical disconnection
4. System in motor mode
The main potential impact areas are:
• Potential for reduction in combustion emissions via adoption in hybrid/electric aviation platforms
• Development of state-of-the-art electric machine and power electronics systems for exploitation on current/future aerospace platforms
• Safety of electric aviation via mitigation of fire from short circuit failure with the implementation of mechanical and electrical disconnection
The key innovations associated are:
• Given the demanding safety requirements and the use of permanent magnet technology, an innovative clutch/mechanical disconnection has been developed which is the subject of a patent application. This facilitates the use of permanent magnet technology and mitigates the risk of fire in the event of a short circuit
• The cooling strategy adopted for the system is novel and includes series air cooling of the electric machine and power electronics, where the airflow is self-extracted by the electric machine. This architecture has benefits over liquid cooling in overall simplicity, inherent reliability, and also reduces the balance of plant of a comparable liquid cooling solution
• The 3-level power electronics system which include dedicated DAL B power controller, DAL A monitoring and protection controller, and isolating contactors
The main results achieved were:
• Development milestones and justification work completed
• Prototypes manufactured to design definition
• Successful test of:
1. System in generator mode (limited)
2. Electrical disconnection
3. Mechanical disconnection
4. System in motor mode
The main potential impact areas are:
• Potential for reduction in combustion emissions via adoption in hybrid/electric aviation platforms
• Development of state-of-the-art electric machine and power electronics systems for exploitation on current/future aerospace platforms
• Safety of electric aviation via mitigation of fire from short circuit failure with the implementation of mechanical and electrical disconnection