基于PowerPC处理器的嵌入式系统电源设计与实现

PowerPC处理器以其多样化功能和优异的性能得到各领域广泛应用。基于此类处理器的嵌入式系统设计将会涉及到许多特殊问题,嵌入式处理系统的电源电路设计就是其中之一。以MPC755为例分析了PowerPC处理器的供电要求和单板计算机的整体电路功能,开展了基于多种电源转换芯片的供电设计,解决了PowerPC处理器嵌入式单板计算机的供电问题。     

Nuclear Power Systems for Spacecraft

A review and comparison of the weights, sizes, and costs of nuclear and non-nuclear spacecraft power systems is presented and discussed. Nuclear power systems include the range below 10 kW, with an electrical output to weight ratio of 0.5 to 1.0 pounds per watt. Comparisons show that primary batteries are lighter for short-duration missions of a few hours; fuel cells are lighter for durations of one to two months; and solar-cell/secondary battery combinations are to be preferred when sunlight is adequate.     

大功率空间核电推进技术研究进展

大功率空间核电推进系统是空间核电源技术和大功率电推进技术的高度融合,具有高能量密度、超高比冲、较大推力的优势,可适用于超大型航天器轨道转移任务、远距离无人深空探测任务、载人火星等大型深空探测任务,能够极大地拓展人类深空探测的能力。本文针对大功率空间核电推进技术,对其工作原理和系统组成进行了介绍,同时开展了关键技术梳理,重点归纳了国内外在技术领域的研究历程和最新进展。     

Computer-Aided Design and Weight Estimation of High-Power High-Voltage Power Conditioners

Aspects of high-power high-voltage power conditioner design and weight estimation relevant to space subsystems are discussed. Weight has become an increasingly important parameter with the advent of larger and more sophisticated spacecraft, especially those for high-power communication. A computer program for estimating the weight of a high-power dc-to-dc power conditioner as functions of output power, operating frequency, input voltage range, maximum input voltage, and efficiency, respectively, is described, including computer-aided design of inductors and transformers. Curves of typical power conditioner weight as functions of the preceding parameters, derived from the power conditioner weight program, are presented.     

High Power Needs for Commercial Satellites

This overview paper presents estimates of the photovoltaic power systems needed on commercial communications spacecraft in the year 2000. These are developed in the form of power requirements based on extrapolation of the historical growth in communications traffic and are about 5 to 15 kW. The paper also addresses the key technology drivers in these photovoltaic systems. The importance of reducing mass in the power system is described in terms of the tradeoff with communications systems mass to maximize communications revenue. It surveys solar array components and subsystems to meet these future requirements and attempts to identify the development candidates with a large payoff potential and a high probability of successful development.     

Conception of spacecraft centralized power supply

A reliable power supply for spacecraft is one of the central problems determining the future development of space technology. The traditional solution to this problem implies having an autonomous power plant on board each spacecraft. The most widely used are power plants with solar cells. However, there exists an alternative power supply concept of using a centralized power supply system (CPSS) and power transmission to the user satellites by laser or microwave beams. Use of a CPSS has a number of advantages. In particular, it allows the spacecraft to increase power supply level and service life as well as to decrease the spacecraft mass and cost. However, it sets new physical and technical problems associated with long distance power transmission and requires some changes in spacecraft structure and concepts. The feasibility study of CPSS development and use has to rely on existing or firmly forecastable technologies. An attempt of such an analysis has been done by a group of scientists at Moscow State Aviation Institute during 1994-1996. The very first results have already been published. This paper discusses new results obtained lately regarding a space based CPSS     

Direct drive options for electric propulsion systems

Power processing units (PPUs) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally greater than 0.9, heat loads are often substantial. This heat must be rejected by thermal control systems which generally have specific masses of 15-30 kg/kW. PPUs also represent a large fraction of the electric propulsion system dry mass. Simplification or elimination of power processing in a propulsion system would reduce the electric propulsion system specific mass and improve the overall reliability and performance. A direct drive system would eliminate all or some of the power supplies required to operate a thruster by directly connecting the various thruster loads to the solar array. The development of concentrator solar arrays has enabled power bus voltages in excess of 300 V which is high enough for direct drive applications for Hall thrusters such as the Stationary Plasma Thruster (SPT). The option of solar array direct drive for SPTs is explored to provide a comparison between conventional and direct drive system mass     

Conical Scanning System for Pioneer Jupiter Spacecraft

The concept, operation, and predicted performance of an RF tracking control system used to point the Pioneer F/G spacecraft at the Earth is described. This system employs a modified conical scanning technique called Conscan. The signal processor, the most interesting unit of the system, is described in detail to show that it approximates a maximum likelihood estimator. The dynamic behavior of the spacecraft and the stability analysis of the system are presented, demonstrating that the system performance is basically determined by the open-loop phase and amplitude errors introduced by the antenna, receiver, and signal processor. A detailed error budget shows that the phase and amplitude errors are small. Finally, closed-loop simulation and test data are presented to verify the error budget.     

Power tracking for nonlinear PV sources with coupled inductor SEPIC converter

The photovoltaic (PV) generator exhibits a nonlinear i-v characteristic and its maximum power (MP) point varies with solar insolation. In this paper, a V2-based MP point tracking (MPPT) scheme is developed using a buck-boost transformation topology. Although several buck-boost transformation topologies are available we have considered here a coupled inductor SEPIC converter for experimentation. To achieve almost ripple-free array current we have used ripple steering phenomena with the help of integrated inductor. This integrated inductor not only reduces the magnetic core requirements but also improves converter performance. Mathematical models are formulated and tracking algorithm is evolved. A combined PV system simulation model is developed in the SIMULINK. For a given solar insolation, the tracking algorithm changes the duty ratio of the converter such that the solar cell array (SCA) voltage equals the voltage corresponding to the MP point. This is done by the tracking algorithm, which mainly computes the power proportional to square of terminal voltage and changes the duty ratio of the converter so that this power is maximum. The proposed algorithm is implemented in real-time with the help of Analog Device ADMC-401 DSP evaluation module. The tracking program is developed to perform experimental investigations using analog-to-digital converter (ADC) interrupt. Using this processor we are able to track the MP within 200 ms. The proposed peak power tracking effectiveness is demonstrated through simulation and experimental results.     

A Comparison of Solar-Cell and Battery-Type Power System for Spacecraft

The electrical power systems of orbiting unmanned spacecraft generally consist of energy-conversion devices in combination with energy-storage and conditioning components. The development of efficient pulse-duration modulation regulators suggests configurations smaller, lighter, and cheaper than conventional dissipative voltage regulators. These savings may or may not be realizable, depending upon the system reliability design goal and amount of redundancy required to meet the goal. Three spacecraft electrical power systems, each containing a solar-cell energy converter and using different voltage regulation schemes, are compared for a common mission specification. Each system is made to meet a given reliability goal by a technique that adds redundant components in a manner that minimizes a system design characteristic such as weight. The reliability design goal is kept constant as mission length is increased, permitting system comparison in terms of weight and cost as a function of time.     

Computer Simulation of Satellite Electric Power Systems

A computer program concept is described for performing an electrical analysis and a transient thermal analysis of a satellite electric power subsystem consisting of a solar array, battery, and power controls. The program "flies" the power subsystem and certain thermally sensitive portions of the spacecraft through one or more complete orbits, and plots curves of voltages, currents, temperatures, and energy balance in critical parts of the power and thermal subsystems.     

一种动态电源供电系统的设计实现方法

为将动态电压调整技术应用于设计中进行功耗优化,阐述了动态电源调整技术、电压识别技术、PMBus总线等基础知识,提出了一种动态电源供电系统的设计方案。采用UCD9222控制器和UCD7242驱动器的设计实例,介绍了动态电源供电系统的配置管理和实现方法,实现了对处理器内核供电电压的动态供电,具有通用性和易用性等优点,可以有效降低系统功耗,满足动态电源供电的设计需求。     

A Kilowatt Rotary Power Transformer

Many future satellite configurations will require the transfer of signals and power across rotating interfaces. Satellite systems are particularly cost effective for both commercial and military communications applications if their useful lifetime can be demonstrated to be greater than five years. The rotary transformer has the desireable characteristics of high reliability and low noise which qualify it as a potential replacement for slip rings. This paper describes the development of a rotary transformer for typical spacecraft applications. The transformer is built in modular sections, each capable of transferring 500 watts across a gap at efficiencies greater than 88 percent, dc to dc. The design effort included a study of pertinent electrical characteristics required for typical spacecraft configurations, electrical design and analyses of the overall dc-dc converter, mechanical design of the transformer cores and their assembly, and a study of transformer core and winding characteristics. Breadboard test results have demonstrated the desired level of efficiency, satisfactory operation over temperature, and satisfactory electrical characteristics.     

Self-Adapting dc Converter for Solar Spacecraft Power Supply Selbstanpassender Gleichstromwandler für die Energieversorgung eines Sonnensatelliten

The voltage-current characteristic of solar cells that provide power for a spacecraft can vary over a wide range. For maximum power transfer from the solar cells to the battery system a power converter has to be designed that adjusts its input impedance to a value equal to the output impedance determined by the operating power characteristic of the solar cells. This paper discusses a circuit and calculations for a design to match this condition. The proposed power converter is simple, lightweight, and reliable and will be used in the Sunblazer satellite.     

利用变速控制力矩陀螺的航天器集成能量与姿态控制

 利用变速控制力矩陀螺(VSCMG)的航天器姿态与能量一体化控制问题。针对以VSCMG为姿态控制执行机构的刚体航天器设计了全局渐近稳定的姿态跟踪控制律。将VSCMG的框架角速度和转子角加速度作为控制输入向量设计操纵律。利用加权的最小范数解得到VSCMG的姿态控制输入向量,并用与之正交的控制输入向量来以给定的功率存储/释放能量。提出了同时表征力矩陀螺模式构型奇异和转子轮速平衡的混合指标函数。对控制自由度有冗余的系统,在混合指标函数的基础上利用梯度法构建了VSCMG的空转运动,以回避力矩陀螺模式的构型奇异,并同时减小转子转速差过大引起的转速饱和以及VSCMG零奇异的可能性。利用反馈转子动能的方法规划日照期间的储能功率,以维持系统长时间工作的能量平衡。基于某太阳同步轨道卫星的数值仿真结果验证了系统的有效性。     

Design and Development of a Real-Time DSP and FPGA-Based Integrated GPS-INS System for Compact and Low Power Applications

Emphasis of the present work is on an elegant real-time solution for GPS/INS integration. Micro-electro mechanical system (MEMS) based inertial sensors are light but not accurate enough for inertial navigation system (INS) applications. An integrated INS/GPS system provides better accuracy compared with either INS or GPS, used individually. This paper describes an improved design and fabrication of a loosely coupled INS-GPS integrated system. The systems currently available use commercial off-the-shelf (COTS) hardware and are, therefore, not optimized for compact, single supply, and low power requirements. In the proposed system, a digital signal processor (DSP) is used for inertial navigation solution and Kalman filter computations. A field programmable gate array (FPGA) is used for creating an efficient interface of the GPS with the DSP. Direct serial interface of the GPS involve tedious processing overhead on the navigation processor. Therefore, a universal asynchronous receiver transmitter (UART) and dual port random axis memory (DPRAM) are created on the FPGA itself. This also reduces the total chip count, resulting in a compact system. The system is designed to give real time processed navigation solutions with an update rate of 100 Hz. All the details of this work are presented.     

Solar power system options for the Radiation and TechnologyDemonstration spacecraft

The Radiation and Technology Demonstration (RTD) Mission has the primary objective of demonstrating high-power (10 kilowatts) electric thruster technologies in Earth orbit. This paper discusses the conceptual design of the RTD spacecraft photovoltaic (PV) power system and mission performance analyses. These power system studies assessed multiple options for PV arrays, battery technologies and bus voltage levels. To quantify performance attributes of these power system options, a dedicated Fortran code was developed to predict power system performance and estimate system mass. The low-thrust mission trajectory was analyzed and important Earth orbital environments were modeled. Baseline power system design options are recommended on the basis of performance, mass and risk/complexity. Important findings from parametric studies are discussed and the resulting impacts to the spacecraft design and cost     

新世纪小型发电装置的开发研究

分布式发电计划涉及到新世纪小型发电机组 (一般低于 30MW)的开发研究。该计划的最终目标是在 2 0 15年提供效率高达 80 %、接近零污染物排放和廉价的发电装置。通过对该计划相关资料的分析 ,介绍了这一计划的主要内容和执行情况 ,燃料电池和高性能燃机研究开发最新动向 ,高性能陶瓷基复合材料 ,燃料处理器等关键技术。     

Minus 35kV Space-Borne Instrument Power Supply

A -35kV power supply has been developed for a plasma experiment on the out-of-ecliptic mission. In addition, an isolation transformer has been developed to provide low voltage power at the -35kV potential. The design features incorporated to produce a spaceflight power supply housed within a 4 × 4 × 2.5 in package are discussed. The supply is powered from an unregulated spacecraft bus and provides a regulated output of -35kV ± 5 percent with less than 0.5 percent ripple over a temperature range -20°C + 60°C. The unit serves as a bias supply with an output current less than 0.5 , ?A. With the supply essentially operating unloaded, 5 percent regulation is achieved by sensing and regulating the first stage of a 12-stage Cockcroft/Walton multiplier. Control of the ac voltage input to the multiplier stack provides the regulation. The isolation transformer utilizes a ferrite u-core with the primary and secondary windings placed on opposite legs for separation. The transformer is encapsulated with the power supply.