Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ESTEEM (Advanced Energy STorage and Regeneration System for Enhanced Energy Management )

Teaser

The concept of ESTEEM is to design and manufacture an innovative Energy Storage and Regenerative System (ESRS) consisting of Electrical Power Distribution System (SEPDC) and embedded SuperCapacitors (SCs) Energy Storage Device (ESD) to demonstrate the concept of Enhanced...

Summary

The concept of ESTEEM is to design and manufacture an innovative Energy Storage and Regenerative System (ESRS) consisting of Electrical Power Distribution System (SEPDC) and embedded SuperCapacitors (SCs) Energy Storage Device (ESD) to demonstrate the concept of Enhanced Electrical Energy Management on controlling the power requirements of a regenerative ElectroMechanical Actuator (EMA) load and hence reduce generator overloading and transient stress. The main objectives of ESTEEM are:

o To identify the ESRS system components, design specifications and core requirements in terms of power ratings, power density, control, safety, communication protocol, cooling and energy management of a regenerative EMA and Enhanced Electrical Energy Management (E2-EM) functionalities.
o To perform a set of trade-off studies and conceptual designs of the ESRS components.
o To develop a set of functional and behavioural level models of the ESRS demonstrator components.
o To design and develop a novel DC/DC converter (structure/topology) for interfacing the supercapacitors ESD with the SEPDC and with the capability of rapid change of operating mode from buck to boost and vice versa.
o To select the supercapacitor technology which will achieve the best trade-off between energy and power density, power loss, maintenance free operation, component life time and safety. An innovative supercapacitors ESD will be designed and assembled.
o To develop an advanced, intelligent, and adaptive control algorithm for the DC/DC converter.
o To design and develop an EMA load emulator.
o To develop an innovative energy management strategy for the ESRS. The optimal reference power of the DC/DC converter will be determined by the energy management supervisor.
o To transform the developed smart energy management strategy to a firmware for the supervisor computational core. Simulation based approaches will be developed. An easy approach for programming the system controllers via USB or RS232 of a Laptop will be considered and developed.
o To manufacture the ESRS system components and to assemble the overall system.
o To demonstrate and test the functionalities of the developed ESRS components, the developed energy management strategy, the E2-EM functionalities and to investigate the performance and power quality of the SEPDC during regeneration and transient variations of loads under the control of the “Iron Bird” as well as in autonomous control mode.

Work performed

o An understanding and development of the scope of works was defined, including identifying design specifications for the SCs unit, and matching the interfacing converter and the SCs design requirements.
o Electrostatic double-layer capacitor (EDLC) technology was selected for building the SCs unit. The SCs unit is designed using a 350F cell from Maxwell.
o Methods for SCs stack energy managements and cell voltage balancing were reviewed and evaluated. Simple and efficient scheme is identified and under development.
o Thermal modelling and losses calculations of the DC/DC converter and the SCs unit were carried out for the purpose of achieving effective thermal management for SCs energy storage system. The SCs cell thermal model was developed using test data captured from laboratory tests where the power losses of the SCs was measured and the temperature change was monitored.
o Different DC/DC converter topologies together with different semiconductor devices were considered for ESTEEM trade-off study. Two phase interleaved DC/DC converter topology with GaN semiconductor devices was decided and designed.
o Trade-off study of different schemes for EMA emulation was carried out and a simple electronic EMA emulator topology was chosen, where a controlled resistor load was used to emulate the motoring action, and a small controlled capacitors based energy storage unit was selected to emulate the regenerative action of the EMA emulator.
o Sliding mode control approach was used for the control of the DC/DC converter of the SC energy storage system and the EMA emulator system.
o Functional and behavioural models of the system components, SCs, DC/DC converter and EMA emulator were developed in Matlab.
o Preliminary studies into smart energy management and SEPDC configuration, and firmware definition and communication protocol were performed. The E2-EM strategy for ESTEEM ESS system was designed and validated by simulation. The E2-EM algorithm was implemented using Simulink/Matlab models and the simulation results obtained showed that the effective use of the SC unit energy storage smoothed the generator current and hence reduced the overloading.
o The ESTEEM supervisor consisting of a finite state automaton was designed. The Matlab models of the ESTEEM system and the supervisor were integrated using co-simulation approaches, in order to verify the overall E2-EM energy management strategies. Different testing scenarios were carried out to validate the correctness of the developed E2-EM and the supervisor design against the system requirements.
o Automatic code generation of the supervisor for the ESTEEM DSP board (Zynq®-7000 family) was performed using Matlab Embed Coder Support package.
o Detailed design of the converters and initial circuit board design is ongoing.

Final results

ESTEEM will deliver a number of ground breaking achievements beyond state-of-the-art to enable successful development of a novel EPDS concept by delivery of an innovative ESRS demonstrator based on supercapacitors energy storage with its interfacing DC/DC converter for on-fly change of operational mode (buck/boost) compatible with the Enhanced Electrical Energy Management concept. The project will also develop an intelligent energy management strategy and corresponding algorithms for smart control of regenerative EMA load and minimising the stress on generators. A communication protocol with smart supervisor algorithm will be also developed for interfacing the ESRS with the \'Iron Bird\' system. The expected project results will contribute towards the competitiveness of the European providers by achieving a significant weight, cost and fuel burn saving for future more-electric aircraft whilst ensuring reliable, effective, safe and low-maintenance operation.

Website & more info

More info: https://www.nottingham.ac.uk/aerospace/projects/cleansky/esteem-project.aspx.