TDC-GP1器件单粒子锁定效应的脉冲激光模拟试验研究

文章介绍了单粒子锁定效应脉冲激光模拟试验的工作原理。以时间测量芯片TDC-GP1为试验对象,利用单粒子锁定模拟试验设备开展了无限流保护电阻和有限流保护电阻的单粒子锁定效应脉冲激光模拟试验研究。结果发现:TCD-GP1芯片在20 nJ脉冲激光辐照下发生了单粒子锁定现象。在对照试验中发现,有限流保护电阻的情况下,在发生锁定时不仅能降低锁定大电流和供电电压,而且还能有效地避免器件的功能损伤。     

波音飞机机载通讯设备(HF)618T天线耦合器工作分析

本文详细分析了波音飞机高频通讯(HF)天线耦合器系统的工作原理,着重介绍自动调谐电路中的相位检测器、阻抗检测器、负功率检波器及方式顺序逻辑电路的工作原理。通过对天线耦合器电路分析,弄清自动调谐信号的产生和自动调谐过程,加深对耦合器的理解,可供飞机维护人员参考,提高维护水平。     

霍尔推力器能量损失系统性评价方法

霍尔推力器典型效率在50%左右,其余能量在电离、加速、耦合等过程中耗散掉,为了明确推力器优化设计的重点方向,需要定量地研究各个物理过程中损失的能量。因此,本文从能量损失分析的角度入手研究影响霍尔推力器效率的典型物理过程及机理,建立了针对霍尔推力器能量损失的系统性评价方法,为霍尔推力器设计及优化提供理论支撑。从霍尔推力器能量转化过程入手,并以能量的最终作用对象及性质作为分类的标准,建立了新的能量损失体系,认为霍尔推力器损失的能量主要有：径向羽流动能、阳极沉积热能、壁面沉积热能、电离能、阴极耦合损失。针对各项损失能量建立了实验评估方法,实验结果显示,阳极热沉积、壁面热沉积、羽流发散导致的能量损失是制约霍尔推力器效率的主导因素,其占比分别达到5.2%、24.7%、6.1%。实验测得所有输出功率占输入阳极放电功率比例达到102.1%,经不确定度分析,认为是阳极热沉积、电离能、阴极耦合损失的高估导致的,但该方法诊断得到的各项损失相对数量级关系是确定的,利用实验校核了方法的可行性,为霍尔推力器性能以及设计水平的评价提供了新的视角。     

基于矩阵光学的多程激光放大器准直系统模型分析

多程放大技术成为高功率固体激光装置的主要发展方向,对激光光路进行调试和维护,建立光路准直的数学模型和调整方案很有必要,采用矩阵光学方法,建立了多程放大自动准直系统数学模型,得出了远、近场光斑偏移量与调整量的解析表达式,验证了该自动准直系统光路原理及调整方法的可行性。     

超大功率电推进电源处理单元关键技术研究

针对深空探测等空间任务对超大功率(10kW~100kW范围)电推进系统的需求,通过对国内外超大功率电推进技术的调研,提出了一种50kW超大功率霍尔电推进系统电源处理单元（Power Processing Unit,PPU）设计方案,重点对核心的阳极电源关键技术进行研究,提出了四管Buck-Boost变换器和三相LLC谐振变换器级联的设计方案,为我国超大功率PPU的发展提供了技术参考。     

An internal power angle control strategy for high-speed sensorless brushless DC motors

High-speed Brushless DC Motors(BLDCMs) usually adopt a sensorless control strategy and operate in three-phase six-state drive mode. However, the sampling errors of the rotor position and the driving method increase the Internal Power Angle(IPA), resulting in a decrease in the efficiency of the system. Conventional IPA reduction strategies are either sensitive to motor parameters, or ignore diode freewheeling during the commutation process, or require additional current sensors. In this paper, a ...     

Utilisation of turboelectric distribution propulsion in commercial aviation: A review on NASA’s TeDP concept

Emissions produced by the aviation industry are currently a severe environmental threat; therefore, aviation agencies and governments have set emission targets and formulated plans to restrict emissions within the next decade. Hybrid aircraft technology is being considered to meet these targets. The importance of these technologies lies in their advancements in terms of aircraft life cycles and environmental benignity. Owing to these advancements, hybrid electric systems with more than one power source have become promising for the aviation industry, considering that the growth of air traffic is projected to double in the next decade. Hybrid technologies have given future hybrid fans and motor-fan engines potential as alternative power generators. Herein, Turboelectric Distributed Propulsion (TeDP) is discussed in terms of power distribution and power sources. The fundamentals of turbofan and turboshaft engines are presented along with their electricity-generation mechanism. TeDP is discussed from a design viewpoint, with a detailed discussion of different types of hybrid electric and turboelectric systems. Examples of proposed TeDP aircraft models and numerical modelling tools used to simulate the performance of TeDP models are reviewed. Finally, innovative turboelectric systems in which electric power savers and mechanical gear changers have been discarded for weight optimisation are presented along with other prospective models, engines, approaches, and architectures. The findings of this review indicate the knowledge gaps in the field of numerical modelling for NASA’s TeDP and its capability to increase the efficiency by up to 24% with a 50% reduction in emissions relative to those of conventional gas turbines.     

Warhead power assessment based on double hierarchy hesitant fuzzy linguistic term sets theory and gained and lost dominance score method

Warhead power assessment of the anti-ship missile plays a vital role in determining the optimal design of missile, thus having important strategic research significance. However, in the assessment process, expert’s judgement will directly affect the assessment accuracy. In addition,there are many criteria involved in the missile design alternatives. Some criteria with poor performance may be compensated by other criteria with excellent performance, and then it is impossible to find the truly opt...     

基于Hdot指令的舰载机两种动力补偿控制系统研究

舰载机着舰时采用动力补偿系统可在很大程度上减轻飞行员的操纵负担,提高动态响应速度和控制精度。针对舰载机的两种动力补偿控制系统开展研究,基于Hdot指令对迎角保持和速度保持两种进场动力补偿系统分别进行设计和仿真,分析两种补偿系统在风干扰情况下的动力补偿响应情况,并对比仿真结果分析其基本原理。结果表明：迎角保持动力补偿系统稳定迎角的能力大于速度保持动力补偿系统,轨迹控制也比速度保持动力补偿系统快。     

变极性等离子弧焊电源的研制

本文介绍了变极性等离子弧焊电源的工作原理，试验研究了方波交流频率和电流极性比对电弧稳定性、阴极清理作用和热输入的影响。研制的电源不仅频率、电流极性比以及正负半波电流幅值分别可以调节，而且还具有交流载波焊接功能，是一种焊接铝合金的理想电源。