多电飞机电气系统关键技术研究

介绍了多电飞机电气系统关键技术的研究现状和发展趋势,阐述了电源系统结构,PSP和ELMC的结构与功能,电源系统BIT技术与容错技术以及电力作动技术等关键技术,并探讨了上述关键技术的设计方案。     

A Design for Thick Film Microcircuit DC-to-DC Converter Electronics

The design concept for thick film microcircuit dc-to-dc converter electronics used in the power subsystem of the Thermoelectric Outer Planet Spacecraft is presented. Microcircuits have been used in low power logic circuits for nearly ten years, but only recently have these techniques been applied to power subsystem circuits which operate at higher power levels. Thick film microcircuit techniques have been utilized in a dc-to-dc converter reducing weight by 70 percent, volume by 80 percent, and interconnections by 75 percent. The close piece-part spacing allowed short interconnections and lower dissipation, and reduced noise coupling. The developed microcircuit handled total power levels from one watt to twenty-five watts.     

Power Electronics in Space: A Review and Projection

Power electronics has emerged as a distinct field of electrical engineering in recent years. This emergence is closely linked with the development of power control and conversion equipment for space application over the last 20 years. Development of switched-mode power conversion techniques has been the dominant activity in this field, spurred by both the improvements in solid-state power devices and the needs of space systems for light weight, highly efficient techniques for dc power regulation. This history is reviewed and projections are made in the four key areas of circuit fundamentals, components, circuit practice, and applications.     

Control technique for high power factor multilevel rectifier

Three control techniques for a high power factor multilevel pulsewidth modulation (PWM) rectifier are proposed. The proposed rectifier is based on series connection of full-bridge cell to achieve a high power factor, low current distortion, low voltage stress of power semiconductors and two balanced output voltages. The look-up table is used in the proposed control schemes to reduce the hardware circuit. A capacitor voltage compensator is used to balance two dc capacitor voltages in order to obtain high quality PWM voltage pattern. Based on the proposed control schemes, two-level or three-level PWM pattern can be generated on the ac side of the adopted rectifier. The proposed techniques for a high power factor multilevel rectifier illustrate its validity and effectiveness through the respective simulations and experiments. According to the measured results, the current harmonics drawn from the mains meet the International Electrotechnical Commission (IEC) 1000-3-2 limits     

Variable frequency switching in power supply EMI-control: an overview

Spreading the signal spectrum is a widely used technique in telecommunication applications. Variable-frequency and spread spectrum modulation methods can also be utilized in power electronic applications to improve electro-magnetic compatibility (EMC). This paper gives an overview to variable-frequency techniques in power electronics with experimental results.     

Investigation of power gas turbine drives on the basis of mathematical models

A method for investigation of power gas turbine drives on the basis of mathematical models that makes it possible to enhance an information content and precision of existing techniques of power audit is proposed.     

Synthesis Techniques for a Class of SSB-AM-PM Signals

This paper develops synthesis techniques for a particular type of single-sideband sinusoidal carrier which is phase modulated by a subcarrier. Mathematical expressions for signal efficiency, sensitivity of design to parameter variation, and ratio of peak to average power are derived and incorporated in a computer program. Given the desired power ratios for modulated signal components, the program solves for the corresponding modulation parameters and evaluates signal efficiency, design sensitivity, and peak to average power ratio. A sample signal design is presented for clarity.     

传导频谱分析

传导发射是沿电源线或信号线传输的电磁发射,在低频范围内,传导发射是电磁干扰的主要形式。如不采取措施,几乎所有的电子、电气设备电源线的传导发射都得超标,它严重地威胁着其他设备的正常工作。本文对典型的干扰源—开关电源的传导发射频谱进行了分析,并介绍了降低传导干扰的设计方法。     

电传飞行控制作动系统

YF-23A战斗机具有极大的静不安定性,在不开加力的情况下可以实现超声速巡航,其设计目标是在亚声速和超声速均具有优于对手的机动能力,上述要求使得飞行控制作动系统必须具有空前的能力和性能。其独特的飞行和机动包线要求其作动系统在低速时具有高的舵面偏转速率和大的行程,在超声速时要具有附加铰链力矩输出能力,为实现上述目标,开发出具有液压与电能守恒的作动系统。     

Lessons learned from the autonomous power system

The autonomous power system (APS) project at the NASA Lewis Research Center is described. The project is designed to demonstrate the applications of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution systems. It consists of the autonomous power expert system (APEX) for fault detection, isolation, and recovery; the autonomous intelligent power scheduler, for efficient assignment of activity start times and resources; and power hardware (Brassboard) to emulate a space-based power system. Each part of the system was critiqued based on individual performance as well as the ability to interact with the other portions of the APS project. These critiques were used to determine guidelines for new and improved components     

变结构控制系统中的混沌现象

应用相轨迹、功率谱等方法,证实了一类变结构控制系统中存在混沌现象,分析了产生混沌现象的原因并给出不同条件下的混沌图形。     

A modular 550 watt, 25 watts per cubic inch power supply for nextgeneration aircraft

The development of the HVS-550 high-performance power supply is described. The HVS-550 was designed and built utilizing state-of-the-art surface mount construction, low-profile magnetics, and aggressive thermal management techniques. This combination allowed the module height to be only 0.58 in. The unique requirements of the military system that bounded the power-supply parameters are discussed. Cooling is provided either by liquid circulating through the chassis or by conduction through the card edges. The measured power supply efficiency is in excess of 85%, with 11-V output. The output noise spectrum is excellent because of noise-cancelling techniques utilized to achieve the level of performance required by the system     

Generating Nonstationary Random Sequences

A general procedure is given for generating infinite-length random sequences defined by a short-term power spectral density that is slowly time varying. Any shape of a power spectral density can be accommodated, including those that cover a wide dynamic range, and any smooth type of nonstationarity can be accommodated. The procedure is based on digital processing techniques. However, it can be extended to the generation of analog signals. Several examples are given, both for digital and analog signals.     

Series of radiation-hardened, high efficiency converters for high voltage bus

A review of common switching techniques for dc/dc power conversion is presented. The evolution of the forward converter is discussed, leading naturally to the introduction of the double forward converter. Technical details for a series of radiation-hardened converters are then provided. This series was designed for space power management and distribution (PMAD) applications. The successful development of the PMAD converter demonstrated the viability of high voltage bus.     

Optimum Power Division for Phase-Modulated Deep-Space Communications Links

Optimum power division is required in deep-space communications links to maximize transmission range or data rate and to permit efficient performance of both carrier tracking and data reception functions. A simple, graphical technique has been developed for phase-modulated links to determine the particular set of peak phase deviations, or modulation indexes, which results in an optimum power division between the carrier and any combination of sine-wave and square-wave subcarriers. Whereas previous methods for the selection of modulation indexes generally necessitated either lengthy solutions of simultaneous equations or complex computer programs, the methods developed in this paper involve simplified graphical procedures, using the trigonometric and Bessel function expressions which describe the power balance between carrier and subcarriers. The optimization procedure is a valuable tool for preliminary design analysis and should be of interest to communications-system engineers, The techniques developed here are particularly applicable when subcarriers have wide differences in data rates, since under these conditions, it becomes increasingly difficult to select arbitrarily the proper modulation indexes. Channel optimization is developed for both nominal and worst-case link conditions and examples are presented to demonstrate the techniques involved.     

新控制技术与第二代航天飞机

 本文介绍了美国航天飞机的概貌,并指出第二代航天飞机的主要特征是水平起降,要实现水平起降,除了要解决动力装置这个关键问题外,必须采用新的控制技术。本文着重分析新控制技术在实现第二代航天飞机中所起的关键作用,可大大减轻航天飞机的自重。     

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。     

Electric generators: technology status

The use of generators by the military is examined. The factors determining generator size and weight for a given power rating and the generator scaling laws are discussed. Size and weight reduction is shown to be primarily a function of improvements in material properties and cooling techniques     

Repetitively Switched Circuits

The general problem of repetitively switched circuits is solved in closed form using a matrix formalism and eigenvalue techniques. The method is similar to that used in treating alternating gradient focusing in modern accelerators. As a simple example, this method is applied to a dc-dc converter power supply.     

某直升机专用交流地面电源车PSPICE模型仿真分析

针对某直升机专用交流地面电源车系统,建立了PSPICE软件的仿真模型,且进行了系统仿真,研究了基于独立源及受控源的SPWM波产生方法,分析了滤波器参数分布对于系统性能的影响。仿真结果表明该电源系统对于雷达、吊声类冲击性负载有较好的适应性。