Modeling and analysis of power processing systems: Feasibility investigation and formulation of a methodology

A review is given of future power processing systems planned for the next 20 years, and the state-of-the-art of power processing design modeling and analysis techniques used to optimize power processing systems. A methodology of modeling and analysis of power processing equipment and systems has been formulated to fulfill future tradeoff studies and optimization requirements. Computer techniques were applied to simulate power processor performance and to optimize the design of power processing equipment. A program plan to systematically develop and apply the tools for power processing systems modeling and analysis is presented so that meaningful results can be obtained each year to aid the power processing system engineer and power processing equipment circuit designers in their conceptual and detail design and analysis tasks

Generator Power Optimisation for a More-Electric Aircraft by Use of a Virtual Iron Bird

A prodedure is developed to minimise the generator design power within the electric power system of a future more-/ all-electric aircraft. This allows to save weight on the generators and on other equipment of the electic power system. Execution of the optimisation procedure by hand demonstrates the complexity of the problem. An automation of the process shows the capabilities of integrated modelling, simulation and optimisation tools

Power Distribution and Propulsion System for an All-Electric Short-Range Commuter Aircraft—A Case Study

To participate in the transition towards a sustainable use of energy, the aircraft sector needs to be transformed with respect to the energy carrier and propulsion methods. For smaller aircraft, a battery-electric approach is promising. While this will require extensive research and design together with the application of advanced components which are partly not available to this date, general design rules and key parameters and critical components can already be deduced. This publication presents the example design of the full propulsion system for a small commuter aircraft. This serves as a case study to highlight the influence of components and parameters on the overall efficiency and weight of the system. By that, future research can be directed towards the areas of high impact on the realization of all-electric aircraft. A optimization of several motor variants, inverter topologies and power supply grid parameters is performed. The weight of the fully electric propulsion system is dominated by the battery. Therefore, all subsequent components need to be designed towards a high efficiency in opposition to high power density

Motor Drive Technologies for the Power-by-Wire (PBW) Program: Options, Trends and Tradeoffs

Power-By-Wire (PBW) is a program involving the replacement of hydraulic and pneumatic systems currently used in aircraft with an all-electric secondary power system. One of the largest loads of the all-electric secondary power system will be the motor loads which include pumps, compressors and Electrical Actuators (EA's). Issues of improved reliability, reduced maintenance and efficiency, among other advantages, are the motivation for replacing the existing aircraft actuators with electrical actuators. An EA system contains four major components. These are the motor, the power electronic converters, the actuator and the control system, including the sensors. This paper is a comparative literature review in motor drive technologies, with a focus on the trends and tradeoffs involved in the selection of a particular motor drive technology. The reported research comprises three motor drive technologies. These are the induction motor (IM), the brushless dc motor (BLDCM) and the switched reluctance motor (SRM). Each of the three drives has the potential for application in the PBW program. Many issues remain to be investigated and compared between the three motor drives, using actual mechanical loads expected in the PBW program

Multi-Objective Comparative Analysis of Active Modular Rectifier Architectures for a More Electric Aircraft

Aircraft electrification requires reliable, power-dense, high-efficient, and bidirectional rectifiers to improve the overall performance of existing aircrafts. Thus, traditional bulky passive rectifiers must be substituted by active rectifiers, satisfying the requirements imposed by up-to-date standards. However, several challenges are found in terms of power controllability, due to the standardized passive rectifier-based operating conditions. This work presents the implementation of an active rectifier modular architecture for aircraft applications. An analysis of the technical difficulties and limitations was performed and three innovative modular architectures are proposed and designed. In order to find the most suitable architecture, a comparison framework is proposed, focusing on efficiency, volume, and reliability parameters. From the comparative analysis, it can be concluded that the two-stage configuration architecture is a good solution in terms of semiconductor life expectancy and low volume. However, if converter redundancies are required, the single-stage with STATCOM configuration is an excellent trade-off between low volume, redundancy, and cost-effectiveness

Discussion on Electric Power Supply Systems for All Electric Aircraft

The electric power supply system is one of the most important research areas within sustainable and energy-efcient aviation for more- and especially all electric aircraft. This paper discusses the history in electrication, current trends with a broad overview of research activities, state of the art of electrication and an initial proposal for a short-range aircraft. It gives an overviewof the mission prole, electrical sources, approaches for the electrical distribution system and the required electrical loads. Current research aspects and questions are discussed, including voltage levels, semiconductor technology, topologies and reliability. Because of the importance for safety possible circuit breakers for the proposed concept are also presented and compared, leading to a initial proposal. Additionally, a very broad review of literature and a state of the art discussion of the wiring harness is given, showing that this topic comes with a high number of aspects and requirements. Finally, the conclusion sums up the most important results and gives an outlook on important future research topics

Control Strategies for Improving Reliability and Efficiency in Modular Power Converters

The significance of modular power converters has escalated drastically in various applications such as electrical energy distribution, industrial motor drives and More Electric Aircraft (MEA) owing to the benefits such as scalability, design flexibility, higher degree of fault tolerance and better maintenance. One of the main advantages of modular systems is the ability to replace the faulty converter cells during maintenance instead of the entire system. However, such maintenance cycles can result in a system of converter cells with different aging. A system with cells having different aging arises the threats of multiple maintenance, lower reliability and availability, and high maintenance costs. For controlling the thermal-stress based aging of modular power converters, power routing strategy was proposed. The thesis focuses on the different implementation strategies of power routing for modular converters. Power semiconductors are one of the most reliability critical components in power converters, and thermal-stress has been identified as the main cause of their failure. This thesis work concentrates on the power semiconductor reliability improvement algorithms. For improving system lifetime, virtual resistor based power routing algorithms for single stage and multi-stage modular architectures have been investigated through simulations and validated with experiment. A unified framework for routing the power in complex modular converter architectures is defined based on graph theory. Popular converter architectures for Smart Transformer (ST) and MEA applications are modeled as graphs to serve as the basis for developing power flow optimization. The effectiveness of graph theory for optimizing the power flow in modular systems is demonstrated with the help of proposed algorithms

Advanced flight deck/crew station simulator functional requirements

This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented

The design of more-electric engine power systems

The More-Electric Aircraft (MEA) concept is now a well-established concept, following its introduction and development over the previous couple of decades. MEA systems are underpinned by state-of-the-art technologies to realise the reduction of CO2 emissions and increased the effectiveness of on-board power transmission. The More-Electric Engine (MEE) concept is increasingly being seen as a complementary solution for MEA applications. Within this concept, the engine auxiliary systems such as fuel pumps, oil pumps and actuation systems will be replaced by electrically driven equivalents and power will be extracted from multiple different engine shafts for electrical generation, with the potential to achieve significant fuel savings. However, with these changes, a dedicated high-integrity and flexibly reconfigurable MEE multiple-channel power architecture is required. When designing a multiple-channel power architecture for MEE，it should comply with relevant power system design certification standards, requiring the application of a multi-disciplinary design methodology. In this thesis, key design certification and airworthiness standards are reviewed in order to identify those applicable to MEE design. Combining these with traceable qualitative and quantitative design logic, the first power system design rule set for MEE power system architecture baselining is established. Building on this foundational knowledge base, candidate novel multiple-channel power architectures are proposed and evaluated. These studies determine that a high degree of controllability and redundancy is key to achieving high system reliability and resilience in MEE power system architectures. In addition, a review of the research literature in this thesis is shown to reveal a shortage of proposed design and optimisation processes for flexible and redundant MEE-type power systems, making it difficult to maximise the design value of a feasible solution. As interdisciplinary and multi-system design processes can be time-consuming and laborious, this thesis instead presents a concurrent design (Co-design) methodology, addressing both MEE power architecture concepts and power management functions. This novel design process includes an initial coarse optimisation to determine the design space boundaries and exclude unsuitable and over-designed solutions for further detailed design, reducing design iterations. A subsequent collaborative synthesis stage for the concurrent design process is then proposed, in which fault scenario case studies and load shedding factor are used to verify the robustness of the combined MEE architecture and power management solutions to off-nominal operating conditions. This enables the refinement of the solution-space by using the simulated results to highlight the areas of the MEE power architecture that can be further optimised, demonstrating the benefits of knowledge-based collaborative design as a process for multi-criteria design. The contributions to the design of MEE power systems architectures presented in this thesis hence provide end-to-end value to the academic and industrial research community in the formation and design of new MEE concepts, with wider application to technologically-adjacent applications (such as hybrid electric aircraft, or high-integrity dc microgrids) also possible.The More-Electric Aircraft (MEA) concept is now a well-established concept, following its introduction and development over the previous couple of decades. MEA systems are underpinned by state-of-the-art technologies to realise the reduction of CO2 emissions and increased the effectiveness of on-board power transmission. The More-Electric Engine (MEE) concept is increasingly being seen as a complementary solution for MEA applications. Within this concept, the engine auxiliary systems such as fuel pumps, oil pumps and actuation systems will be replaced by electrically driven equivalents and power will be extracted from multiple different engine shafts for electrical generation, with the potential to achieve significant fuel savings. However, with these changes, a dedicated high-integrity and flexibly reconfigurable MEE multiple-channel power architecture is required. When designing a multiple-channel power architecture for MEE，it should comply with relevant power system design certification standards, requiring the application of a multi-disciplinary design methodology. In this thesis, key design certification and airworthiness standards are reviewed in order to identify those applicable to MEE design. Combining these with traceable qualitative and quantitative design logic, the first power system design rule set for MEE power system architecture baselining is established. Building on this foundational knowledge base, candidate novel multiple-channel power architectures are proposed and evaluated. These studies determine that a high degree of controllability and redundancy is key to achieving high system reliability and resilience in MEE power system architectures. In addition, a review of the research literature in this thesis is shown to reveal a shortage of proposed design and optimisation processes for flexible and redundant MEE-type power systems, making it difficult to maximise the design value of a feasible solution. As interdisciplinary and multi-system design processes can be time-consuming and laborious, this thesis instead presents a concurrent design (Co-design) methodology, addressing both MEE power architecture concepts and power management functions. This novel design process includes an initial coarse optimisation to determine the design space boundaries and exclude unsuitable and over-designed solutions for further detailed design, reducing design iterations. A subsequent collaborative synthesis stage for the concurrent design process is then proposed, in which fault scenario case studies and load shedding factor are used to verify the robustness of the combined MEE architecture and power management solutions to off-nominal operating conditions. This enables the refinement of the solution-space by using the simulated results to highlight the areas of the MEE power architecture that can be further optimised, demonstrating the benefits of knowledge-based collaborative design as a process for multi-criteria design. The contributions to the design of MEE power systems architectures presented in this thesis hence provide end-to-end value to the academic and industrial research community in the formation and design of new MEE concepts, with wider application to technologically-adjacent applications (such as hybrid electric aircraft, or high-integrity dc microgrids) also possible