Secondary Power System Research Articles

Swift Assessment of Flexible Elements of High Speed Flexible Couplings for Aircraft Transmission Systems

The High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) is used in combat aircraft for connecting engine gearbox with accessory gearbox to transmit power and to accommodate larger misalignments. The HSFC utilizes series of metallic contoured plates as flexible elements. The development of a HSFC shaft assembly involves high cost and time process. Any failure of the HSFC during flight operation will deprive the secondary power system mainly used for controlling the single engine fighter aircraft. To develop the reliable HSFC with minimum developmental cost and time, an innovative approach termed as Swift Assessment of Flexible Elements (SAFE) for the development of HSFC is evolved. A case study of a typical high speed flexible coupling developed using this approach is presented With the SAFE approach, sufficient level of flexibility in design modification, trim down product development cycle time and cost were realized.

Systems for Secondary Electric Power Supply of the Instruments "Zora" and "Neurolab-B" – Space Medicine

The "Zora" and "Neurolab-B" instruments solved problems related to the study, control and prediction of astronaut health. The "Zora" instrument is a computer system for collecting and processing data from complex neurophysiological experiments: "Statokinetiks"; "Labyrinth"; "Potential"; "Leisure Time"; "Questionary", etc. The system for complex research of the psychophysiological state of astronauts "Neurolab-B" is used for scientific experiments with the help of a number of international crews. Engineering solutions are proposed according to the investigated specificity of the powered devices. Both systems have been operating on board the Mir space station – "Neurolab-B" from 1996 to 2000. New space medicine instruments used on the Russian sector of the international space station are considered. Since 2000, four new secondary power systems for space instruments have been developed at the Institute of Space Research and Technology – Bulgarian Academy of Sciences. They are applicable in both space physics and space medicine.

WITHDRAWN: Performance analysis of SRF-based UPQC on polluted electric utility grid

The effectiveness of the UPQC is determined by its control algorithm for generating the reference signal. In this paper, the reference signal generation is based on SRF (Synchronous Reference Frame) algorithm in a UPQC (Unified Power Quality Conditioner). The detailed SRF algorithm with a generation of the reference voltage and current signal are analyzed and implemented using MALAB/Simulink. Secondary distribution power system was created in MALAB/Simulink to analyses the performance of the UPQC before and after connection. The performance UPQC is examined with steady and dynamic conditions and the remarks of SRF algorithm have been concluded.

Three-objective optimization of aircraft secondary power system rotor dynamics

Secondary power system based on gas turbine engine is usually used for starting the aircraft main engine at ground and finds similar application in air during the emergency. The secondary power system comprises of an auxiliary power unit (APU) and an air starter. APU provides stand-alone power to the main engine subsystems and air to the air starter for starting main engine. The main rotor system of APU is to be designed for safe operation during the ground critical speed crossing and maneuver loading. The weight of such a rotor system is an important design criterion. In the current work, multi-objective optimization using hybrid genetic algorithm (HGA) is employed for simultaneously minimizing the response at critical speed, the response during maneuvering, and shaft weight of the APU rotor system used in secondary power system of an aircraft. The shaft considered is a stepped one and is modeled using Rayleigh beam elements with three disks. Effects due to gyroscopic effect are also included in the analysis. A Pareto front is generated, and subsequently, an optimal solution is selected for the problem. The comparison with typical two-objective optimization result, having response at critical speed and shaft weight as objectives and response during maneuvering as constraint, has shown that the novel three-objective optimization has provided the designer with improved design choices for the selection of final compromise solution.

Multi-Objective Optimization Control for the Aerospace Dual-Active Bridge Power Converter

With the development of More Electrical Aircraft (MEA), the electrification of secondary power systems in aircraft is becoming more and more common. As the key power conversion device, the dual active bridge (DAB) converter is the power interface for the energy storage system with the high voltage direct current (HVDC) bus in aircraft electrical power systems. In this paper, a DAB DC-DC converter is designed to meet aviation requirements. The extended dual phase shifted control strategy is adopted, and a multi-objective genetic algorithm is applied to optimize its operating performance. Considering the three indicators of inductance current root mean square root (RMS) value, negative reverse power and direct current (DC) bias component of the current for the high frequency transformer as the optimization objectives, the DAB converter’s optimization model is derived to achieve soft switching as the main constraint condition. Optimized methods of controlling quantity for the DAB based on the evolution and genetic algorithm is used to solve the model, and a number of optimal control parameters are obtained under different load conditions. The results of digital, hard-in-loop simulation and hardware prototype experiments show that the three performance indexes are all suppressed greatly, and the optimization method proposed in this paper is reasonable. The work of this paper provides a theoretical basis and researching method for the multi-objective optimization of the power converter in the aircraft electrical power system.

Secondary power systems for videometric complex "Fregat"

The power supply for the video-spectrometric complex (VSC) "Fregat" is being considered. This secondary power supply systems have the following functions: Reception and switching of the voltages; Protection from overload and short circuit in the internal circuits and the exit circuits; Transformation of primary voltage in stabilized secondary voltages; Galvanically untethered secondary circuits by primary and Hull; Protection of the users from the electromagnetic noises; Provision of "Cold" and "Hot" reserve, etc. A set of technical documentation and test-measuring equipment for testing were created. Four sets of Secondary Power Systems for "Fregat" are designed and implemented for two flights to planet Mars.

A distributed real-time data prediction framework for large-scale time-series data using stream processing

PurposeThe purpose of this paper is to propose a data prediction framework for scenarios which require forecasting demand for large-scale data sources, e.g., sensor networks, securities exchange, electric power secondary system, etc. Concretely, the proposed framework should handle several difficult requirements including the management of gigantic data sources, the need for a fast self-adaptive algorithm, the relatively accurate prediction of multiple time series, and the real-time demand.Design/methodology/approachFirst, the autoregressive integrated moving average-based prediction algorithm is introduced. Second, the processing framework is designed, which includes a time-series data storage model based on the HBase, and a real-time distributed prediction platform based on Storm. Then, the work principle of this platform is described. Finally, a proof-of-concept testbed is illustrated to verify the proposed framework.FindingsSeveral tests based on Power Grid monitoring data are provided for the proposed framework. The experimental results indicate that prediction data are basically consistent with actual data, processing efficiency is relatively high, and resources consumption is reasonable.Originality/valueThis paper provides a distributed real-time data prediction framework for large-scale time-series data, which can exactly achieve the requirement of the effective management, prediction efficiency, accuracy, and high concurrency for massive data sources.

Research on modeling and conduction disturbance simulation of secondary power system in a device

To find electromagnetic interference (EMI) and other problems in the secondary power supply system design quickly and effectively, simulations are carried out under the Saber simulation software platform. The DC/DC converter model with complete performance and electromagnetic characteristics is established by combining parametric modeling with Mast language. By using the method of macro modeling, the hall current sensor and power supply filter model are established respectively based on the function, schematic diagram of the components. Also the simulation of the component model and the whole secondary power supply system are carried out. The simulation results show that the proposed model satisfies the functional requirements of the system and has high accuracy. At the same time, due to the ripple characteristics in the DC/DC converter modeling, it can be used as a conducted interference model to simulate the power bus conducted emission CE102 project under the condition that the simulated load is full, which provides a useful reference for the electromagnetic interference suppression of the system.

A Novel Approach for Phase Balancing of Secondary Distribution Power System

Objectives: The main objective of the power distribution system is to reduce the loss in order to improve the system efficiency, alleviate the cost and increase the consumer satisfaction. Methods/Analysis: Power loss mainly depends on type of the load and its pattern. Load unbalance on distribution feeder leads to current raise in the heavily loaded phase, over voltage in the lightly loaded phase and neutral current and mal functioning of protection equipment. Findings: In power distribution energy management, phase balancing is one among the techniques available to reduce the loss incurred by load unbalance. Phase balancing is a concept of re-phasing service laterals such that load on three phases is balanced. Application/Improvement: The study mainly deals with phase balancing of secondary distribution feeder by rearranging the connections of consumer load/ service laterals. The algorithm is designed to handle time varying loads with an objective of loss reduction and minimum number of phase moves.

Development and validation of a software tool for complex aircraft powertrains

A simulation software for the assessment of performance, costs and environmental impact of conventional and advanced configuration aircraft has been developed and validated. The software is named PLA.N.E.S. (PLAtform for New Environment-friendly Solutions), and includes a sizing routine and a mission simulator. The simulation is performed with the so-called backward paradigm, i.e. the flight conditions along the mission (altitude and speed versus time) are assumed to be known. Accordingly, the instantaneous power request of the aircraft to meet that flight mission and the corresponding instantaneous fuel consumption are calculated. In the case of advanced powertrains, it is also possible to choose different energy management strategies for the optimal control of the energy flows among engine, secondary equipment and storage systems during the mission. The components currently modeled in PLA.N.E.S. include energy converters (piston and Wankel engines, turboprop, fuel cell, etc.), energy storage systems (batteries, super-capacitors), auxiliaries and secondary power systems. The tool is designed to be integrated with a multi-objective optimization environment. In the present investigation PLA.N.E.S. has been applied to a Medium Altitude Medium Endurance (MAME) Unmanned Aerial Vehicle (UAV) as a case study to compare an experimentally validated Wankel-based powertrain with a proposed turbocharged diesel piston-prop system.

二次動力システムを考慮に入れた航空機概念設計手法に関する研究

二次動力システムを考慮に入れた航空機概念設計手法に関する研究

The Development and Solution of Intelligent Secondary Power in Space

Intelligent secondary power supply is a power supply which integrate power conversion , data acquisition, power control ,serial communication features for aviation, aerospace high-reliability power supply system, with the diagnosis, fault protection and power health management function. Intelligent design is a necessary measures to ensure and improve the secondary power performance , is the trend of secondary power supply system of the future, It solve the shortcomings of traditional secondary power system such as poor monitoring , lack of fault identification and diagnostics, improve the reliability of the secondary power supply greatly, has great significance to improve the design of space payload.

Environmental Impact Assessment, on the Operation of Conventional and More Electric Large Commercial Aircraft

Global aviation is growing exponentially and there is a great emphasis on trajectory optimization to reduce the overall environmental impact caused by aircraft. Many optimization techniques exist and are being studied for this purpose. The CLEAN SKY Joint Technology Initiative for aeronautics and Air transport, a European research activity run under the Seventh Framework program, is a collaborative initiative involving industry, research organizations and academia to introduce novel technologies to improve the environmental impact of aviation. As part of the overall research activities, “green” aircraft trajectories are addressed in the Systems for Green Operations (SGO) Integrated Technology Demonstrator. This paper studies the impact of large commercial aircraft trajectories optimized for different objectives applied to the on board systems. It establishes integrated systems models for both conventional and more electric secondary power systems and studies the impact of fuel, noise, time and emissions optimized trajectories on each configuration. It shows the significant change in the fuel burn due to systems operation and builds up the case as to why a detailed aircraft systems model is required within the optimization loop. Typically, the objective in trajectory optimization is to improve the mission performance of an aircraft or reduce the environmental impact. Hence parameters such as time, fuel burn, emissions and noise are key optimization objectives. In most instances, trajectory optimization is achieved by using models that represent such parameters. For example aircraft dynamics models to describe the flight performance, engine models to calculate the fuel burn, emissions and noise impact, etc. Such techniques have proved to achieve the necessary level of accuracy in trajectory optimization. This research enhances previous techniques by adding in the effect of systems power in the optimization process. A comparison is also made between conventional power systems and more electric architectures. In the conventional architecture, the environmental control system and the ice protection system are powered by engine bleed air while actuators and electrics are powered by engine shaft power off-takes. In the more electric architecture, bleed off take is eliminated and the environmental control system and ice protection system are also powered electrically through engine shaft power off takes.

CIM Modeling for Transformer Protection of the Power Secondary Networks

In view of existing situation of the inconsistent power system model, a method of CIM modeling for power secondary system is given, based on better understanding and the analysis of the primary system CIM modeling. Combined with the particular characters of the secondary system, it establishes CIM model for the transformer protection of the secondary networks. Then it shows the method is proper and feasible. Some important issue about further research is put forward as well.

Zonal safety analysis in aircraft conceptual design: application to SAvE aircraft

The article presents an innovative zonal safety analysis method that can be applied to future products in conceptual design and discusses the results of the application of this technique to two different configurations of the all electric secondary power system (the conventional configuration and the hybrid fuel cells configuration) of a future medium altitude long endurance unmanned aerial vehicle, the system for unmanned aerial vehicle advanced alternative energy aircraft. Main advantages and criticalities of the application of the zonal safety analysis very early during the design process are addressed first, together with the description of the main characteristics of system for unmanned aerial vehicle advanced alternative energy aircraft. Then, the methodology, that has been used, is described in detail and the main results of the application of the zonal safety analysis to two significant aircraft bays are shown and discussed. Eventually, the main conclusions are drawn and the choice of the best configuration from the safety point of view is made.

Design of all electric secondary power system for future advanced medium altitude long endurance unmanned aerial vehicles

System for unmanned aerial vehicles (UAV) advanced alternative energy (SAvE) is a research project funded in 2007 by Piemonte Regional Government, Italy, and assigned to Politecnico di Torino and Alenia Aeronautica. Aim of the project is the study of new, more efficient, more effective, and more environmentally friendly on board systems for future advanced UAV, particularly for future advanced medium altitude long endurance (MALE) UAVs. This article deals with the analysis and design of the all electric secondary power system of a future advanced MALE UAV that is considered as ‘reference aircraft’. After a thorough trade-off analysis of different configurations of the secondary power system, the hybrid fuel cells configuration, characterized by starter/generators, fuel cells, and traditional and innovative batteries, has been selected as the most promising. Detailed investigations to find the best way to apportion the supply of secondary power, considering the various power sources (starter/generators, batteries, and fuel cells) in the different modes of operations, have been performed thanks to an integrated simulation environment, where physical, functional, and mission scenario simulations continuously exchange data and results.

Effects of Off-takes for Aircraft Secondary-Power Systems on Jet Engine Efficiency

Effects of Off-takes for Aircraft Secondary-Power Systems on Jet Engine Efficiency

Satellite multi-functional power structure: Feasibility and mass savings

A multi-functional structure saves mass from a spacecraft by incorporating other functional subsystems into the structure. By using the structural properties of a non-structural element, inert structure may be eliminated, and the requirement to allot internal volume to the subsystem in question is removed. The current paper describes a multi-functional structure based on the secondary power system. By using commercially available plastic lithium-ion cells to form the core of a sandwich panel, inert mass is eliminated from both the structure and from the battery enclosure. The feasibility of the proposed multi-functional structure is demonstrated though vibration testing on a single cell, and the successful manufacture of a test panel. The work goes on to quantify the potential mass savings that may be achieved by using a multi-functional structure of this type. By varying a set of spacecraft attributes, the study identifies that small spacecraft with high power requirements have the potential to gain the most benefit from using a multi-functional structure of this type.

Restoration strategy for secondary power network with grey relational analysis

An operational strategy for secondary power system restoration using grey relational analysis (GRA) is presented. The restoration scheme can be divided into three steps involving fault section determination, recovering process and voltage correction process. Three GRAs are incorporated to design the overall restoration scheme. The first GRA uses the network-switching status to identify the fault. The second GRA combines the switching states and load levels for network recovery. The third GRA uses capacitor bank control (CBC) to support bus voltages. Optimal power flow (OPF) is also used to verify the proposed scheme by off-line analysis to confirm a secure overall network operation including load–power balance, power generation limits, voltage limits and power flow limits. Computer simulations were conducted with an IEEE 30-bus power system to show the effectiveness of the proposed restoration scheme.

Worthy test programmes and developments of smart electromechanical actuators

Early aircraft flight control systems were totally manually operated, that is, the forcerequired to move flight control surfaces was generated by the pilot and transmitted bycables and rods. As aerodynamics and airframe technology developed and speeds increased,the forces required to move control surfaces increased, as did the number of surfaces. Inorder to provide the extra power required, hydraulic technology was introduced.To date, the common element in the development of flight control systems hasbeen, mainly, restricted to this type of technology. This is because of its provenreliability and the lack of alternative technologies. However, the technology to buildelectromechanically actuated primary flight control systems is now available.Motors developing the required power at the required frequencies are now possible(with the use of high energy permanent magnetic materials and compact highspeed electronic circuits). It is this particular development which may make theconcept of an ‘all electric aircraft’ realizable in the near future. The purposeof the all electric aircraft concept is the consolidation of all secondary powersystems into electric power. The elimination of hydraulic and pneumatic secondarypower systems will improve maintainability, flight readiness and use of energy.This paper will present the development of multi-lane smart electric actuators and offer aninsight into other subsequent fields of study. The key areas of study may be categorized asfollows.State of the art hydraulic actuators.Electromechanical actuator system test programmes.Development of electromechanical actuators.Modelling of electromechanical actuators.