Overview
The main aim of this project was to develop a flexible power conversion system incorporating multiple energy sources, as well as energy recovery and storage capability. The power system was developed for use with the 270V DC power distribution network, typical of avionic applications.
Safety and HW/SW certification factors were taken into due consideration, either during the system and sub-system architecture definition, or during the design and development phase, when failure modes effects and robustness analyses will be performed both at system level and component level as deemed necessary.
It assessed the suitability and potentialities of novel energy storage technologies and provided a thorough and in-depth analysis of energy transfer management and control in order to ensure maximum flexibility of exploitation and optimised system performance.
It delivered a fully controlled power conversion system capable of efficient managing of the regenerated and stored energy for use during peak power demands from the load.
The required demonstration phase, when the system was integrated and subjected to performance testing and compliance to the application through a test rig designed for purpose, has been considered.
Funding
Results
Executive Summary:
The REGENESYS system forms part of the overall Cleansky Green Rotorcraft Integrated Technology Demonstrator.
The objective of REGENESYS was to develop the demonstrator of a flexible power conversion system incorporating multiple energy sources, as well as energy recovery and storage capability that can be further developed toward a new aircraft power distribution system which by the use of energy recovery, storage and subsequent managed distribution reduced the energy footprint of the aircraft leading to reduced mass, maintenance, emissions and noise.
Specifically, REGENESYS is intended to provide a technology demonstrator comprising:
- Bidirectional power converters (BDC) which interface to a nominal 270VDC power bus with the capability to connect at their output to either energy storage elements either loads
- Energy storage element(s)
- Variable loads
- CCU and associated SW
The goal was to demonstrate a system that intelligently controlled all bidirectional converters interfacing loads or energy storage components of the system to provide a stable, flexible power distribution.
Following an initial phase of research into all aspects of the system requirements, the key technologies required to implement the system have been identified.
As an outcome of this research, a series of technical specifications have been defined for each sub-system of the REGENESYS Demonstrator.
Essentially the system has been subdivided into the following major sub-systems:
- 270V to 28V 1.2KW bidirectional converters (BDC’s)
- 270V to Energy Storage System bidirectional converter (BDCR)
- Energy Storage system capable of storing regenerative energy from a Rotor Brake (peak energy of 30KW) following landing, also energy storage from other regenerative loads
- A central Control Unit (CCU) for control of the Test Rig and the REGENESYS Demonstrator
- A comprehensive Test Rig accommodating the REGENESYS Demonstrator and providing for full system and sub-system testing
Each equipment has been designed, developed, built, and tested in accordance with the defined specifications.
Following prototyping and characterisation of the BDC, the design has been engineered to a TRL6 level and five units assembled, tested, and characterised.
The BDCR has been prototyped and characterised and then a second unit engineered at TRL5 level into a 6U 19” rack sub-assembly.
For the Energy Storage sub-system, a Lithium Titanate battery solution has been identified, obviating the need for a supercapacitor pack as originally conceived. This has resulted in a five-section battery pack, each section comprising 15 cells. The overall battery pack therefore comprising 75 13Ahr cells, providing a nominal voltage of 185V.
The Test Rig has been designed, built, tested, and integrated. The REGENESYS Demonstrator equipment has been incorporated.
The REGENESYS System Demonstrator has been successfully tested against the defined System & Sub-systems Test Plan. The system of multiple BDC’s is stable, some minor problems associated with instability of the BDCR converter at high power.