Energy Storage System Control for Energy Management in Advanced Aeronautic Applications

In this paper an issue related to electric energy management on board an aircraft is considered. A battery pack is connected to a high-voltage bus through a controlled Battery Charge/Discharge Unit (BCDU) that makes the overall behaviour of the battery “intelligent.” Specifically, when the aeronautic generator feeding the high-voltage bus has enough energy the battery is kept under charge, while if more loads are connected to the bus, so that the overload capacity of the generator is exceeded, the battery “helps” the generator by releasing its stored energy. The core of the application is a robust, supervised control strategy for the BCDU that automatically reverts the flow of power in the battery, when needed. Robustness is guaranteed by a low-level high gain control strategy. Switching from full-charge mode (i.e., when the battery absorbs power from the generator) to generator mode (i.e., when the battery pumps energy on the high-voltage bus) is imposed by a high-level supervisor. Different from previous approaches, mathematical proofs of stability are given for the controlled system. A switching implementation using a finite-time convergent controller is also proposed. The effectiveness of the proposed strategy is shown by detailed simulations in Matlab/Stateflow/SimPowerSystem

Boost converter fed high performance BLDC drive for solar PV array powered air cooling system

This paper proposes the utilization of a DC-DC boost converter as a mediator between a Solar Photovoltaic (SPV) array and the Voltage Source Inverters (VSI) in an SPV array powered air cooling system to attain maximum efficiency. The boost converter, over the various common DC-DC converters, offers many advantages in SPV based applications. Further, two Brushless DC (BLDC) motors are employed in the proposed air cooling system: one to run the centrifugal water pump and the other to run a fan-blower. Employing a BLDC motor is found to be the best option because of its top efficiency, supreme reliability and better performance over a wide range of speeds. The air cooling system is developed and simulated using the MATLAB/Simulink environment considering the steady state variation in the solar irradiance. Further, the efficiency of BLDC drive system is compared with a conventional Permanent Magnet DC (PMDC) motor drive system and from the simulated results it is found that the proposed system performs better

Spacecraft power

Solar cell spacecraft power systems, and measurements of Mariner-type and Surveyor batterie

Direct sequence spread spectrum based PWM strategy for harmonic reduction and communication

Switched mode power supplies (SMPSs) are essential components in many applications, and electromagnetic interference is an important consideration in the SMPS design. Spread spectrum based PWM strategies have been used in SMPS designs to reduce the switching harmonics. This paper proposes a novel method to integrate a communication function into spread spectrum based PWM strategy without extra hardware costs. Direct sequence spread spectrum (DSSS) and phase shift keying (PSK) data modulation are employed to the PWM of the SMPS, so that it has reduced switching harmonics and the input and output power line voltage ripples contain data. A data demodulation algorithm has been developed for receivers, and code division multiple access (CDMA) concept is employed as communication method for a system with multiple SMPSs. The proposed method has been implemented in both Buck and Boost converters. The experimental results validated the proposed DSSS based PWM strategy for both harmonic reduction and communication

Recent Technologies and Control Methods for Electric Power Systems in More Electric Aircrafts: A Review

This paper is aimed at discussing the current trends in the design of Electric Power Systems (EPS) architectures which are intended to be implemented in More Electric Aircrafts (MEAs). Various EPS architectures such as HVAC, HVDC, hybrid HVAC/HVDC etc are studied and compared. Various control techniques which are implemented in order to control the EPS are also reviewed and they are compared on the basis of power quality, ease of installation and maintenance, possibility of future expansion of EPS, need of active power filters and so on. On the basis of the evaluation of various EPS architectures, the need of fuel cell installation in the EPS to be used for MEAs is explained and various ways to incorporate the fuel cell in the said EPS are discussed. Further the need of DC to DC converters in the power grid of a MEA is discussed and various possible choices for the topologies of DC to DC converters are compared on the basis of the parameters such as efficiency, transient response, reliability, electromagnetic emissions, size, weight and so on. Moreover, various controllers such as PI controller, PID controller, Sliding Mode Controller etc which can be used for a closed loop control of DC to DC converters are discussed

More Electricity in the Air: Toward Optimized Electrical Networks Embedded in More-Electrical Aircraft.

Along with the main trends and future challenges of electrical networks embedded in more-electrical aircraft, this article also focuses on optimization efforts in the field of industrial electronics and energy conversion. Optimization can be achieved by the means of expertise or from classical analysis methods, especially those based on simulations. However, novel approaches based on optimization algorithms, so-called integrated design by optimization, are becoming increasingly mature and will become particularly powerful if subsequent efforts are made in terms of modeling for design. In the first part, the current context and new standards of the more-electrical aircraft are summarized. The second part deals with the new trends and challenges of more electrical aircraft, with an emphasis on reversible and hybrid high-voltage dc networks including new storage devices. However, this discussion will mainly focus on systems optimization. Methodological orientations toward integrated optimal design are discussed with representative examples, such as for an environmental conditioning system (ECS)

Control of Energy Storage Systems for Aeronautic Applications

Future aircraft will make more and more use of automated electric power system management onboard. Different solutions are currently being explored, and in particular the use of a supercapacitor as an intelligent energy storage device is addressed in this paper. The main task of the supercapacitor is to protect the electric generator from abrupt power changes resulting from sudden insertion or disconnection of loads or from loads with regenerative power capabilities, like electromagnetic actuators. A controller based on high-gain concepts is designed to drive a DC/DC converter connecting the supercapacitor to the main electric bus. Formal stability proofs are given for the resulting nonlinear system, and strong robustness results from the use of high-gain and variable structure control implementation. Moreover, detailed simulations including switching devices and electrical parasitic elements are provided for different working scenarios, showing the effectiveness of the proposed solution

Advanced Stirling Convertor Testing at NASA Glenn Research Center

The U.S. Department of Energy (DOE), Lockheed Martin Space Systems (LMSS), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science and exploration missions. This generator will make use of the free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. The ASRG will utilize two Advanced Stirling Convertors (ASC) to convert thermal energy from a radioisotope heat source to electricity. NASA GRC has initiated several experiments to demonstrate the functionality of the ASC, including: in-air extended operation, thermal vacuum extended operation, and ASRG simulation for mobile applications. The in-air and thermal vacuum test articles are intended to provide convertor performance data over an extended operating time. These test articles mimic some features of the ASRG without the requirement of low system mass. Operation in thermal vacuum adds the element of simulating deep space. This test article is being used to gather convertor performance and thermal data in a relevant environment. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto devices powered directly by the convertors, such as a rover. This paper discusses the design, fabrication, and implementation of these experiments

Design and Modelling of a Bidirectional DC-DC Converter based on Full Bridge Current Doubler Topology for Aeronautical Applications

This project falls within the framework of the research about More Electric Aircraft (MEA) concept, which is the target of the current designs. In this context, electrical system is being reinforced as one of the main power systems. Electrical power level and voltage level transmission are increasing –the last one is tending to High Voltage Direct Current (HVDC) level– and requirements of generation, distribution, management and control of this kind of power are becoming more and more challenging. Within electrical system, power converters are responsible for electrical power transmission. Moreover, they must fulfil aeronautical standards in respect of on-board electrical and electronic systems. The precise aim of this project is to study suitable topologies for DC-DC bidirectional and isolated power converters within defined framework. Many industries, as aeronautical or automotive, request them with better features –for instance, power density and e ciency are critical KPI in aeronautical industry–. After a review of main power circuits that could fulfil specifications for these applications, a promising topology will be analysed from a numerical point of view. Particularly, Bidirectional Current Doubler is the topology subject of study. Its working principle will be analysed under certain operating range domain. Simulation models will be developed to asses topology performance in such operating domain. By knowing currents and voltages on ideal elements, a more realistic components selection will be carried out, particularly as far as MOSFETs concerns. Finally, regarding a more little bit accurate model, e ciency will be calculated in terms of input and output power.Universidad de Sevilla. Máster en Ingeniería Aeronáutic