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本文首先简单介绍了飞机起动发电系统的发展现状,然后简要分析基于DSEM的飞机起动发电系统的系统结构以及相应的运行原理,对比了其与三级式同步电机以及开关磁阻电机起动发电系统的运行差异,最后明确了研究基于DSEM的起动发电技术的重大意义。 相似文献
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<正>28V直流电源系统是飞机上非常成熟的一种电源系统,其结构简单,且易实现并联运行和起动发电功能一体化。飞机发电机需要调压器来保证输出电压基本保持稳定,满足相关技术指标规定和机载用电设备需求。目前仍在广泛使用的一种是炭片式调压器,常见于比较老的飞机。 相似文献
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如图所示:原理:(1)首先先闭合开关B,断开开关A,使直流电变为交流电,然后让电动机①带动发电机②,使发电机②发出电来。(2)由于转轮⑤上有两个支铁球,让其跟转轮转动,所以产生惯性。等转轮⑤转到最快速度时,产生了最大惯性,就闭合开关A,使通电螺线管将弹片⑨吸下来,电源到发电机①的电路就断开。(3)电源电路断开,而发电机②到电动机①的电路是闭合的,所以发电机供电给电动机,而电动机又可以带动发电机,又可发出电来,这样周而复始。(4)这样首先用点电起动电动机,然后断开电源,让电动机带动发电机,自己产出电来,这就是节能发电机。A——开关;… 相似文献
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塞斯纳525飞机的电源系统是一个直流电源系统,该系统通过一些电气部件实现了飞机电能的产生、调节、控制与指示。奖状飞机安装了两台起动机发电机,它是飞机电源系统的核心部件。我分院的4架奖状飞机已经发生过8次起动发电机的故障。起动发电机故障对于飞机飞行安全有重要影响。因此通过对起动发电机故障的研究,对飞机电源系统可靠性的提升有重要作用。 相似文献
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塞斯纳525飞机的电源系统是一个直流电源系统,该系统通过一些电气部件实现了飞机电能的产生、调节、控制与指示。奖状飞机安装了两台起动机发电机,它是飞机电源系统的核心部件。我分院的4架奖状飞机已经发生过8次起动发电机的故障。起动发电机故障对于飞机飞行安全有重要影响。因此通过对起动发电机故障的研究,对飞机电源系统可靠性的提升有重要作用。 相似文献
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<正>航空三级式同步电机由永磁副励磁机、同步励磁机、旋转整流器和主同步电机构成,目前主要作为发电机使用。由于其结构特点,在同步励磁机励磁绕组内通入交流电,即可使主同步电机励磁绕组获得励磁电压,建立起动运行初始磁场,此时在主同步电机定子绕组内通入适当的三相交流电压,即可获得电磁转矩以克服阻力实现起动。目前针对现有的航空三级式同步电机起动运行励磁方法研究颇多,但不改变现有电机本体绕组结构的方法仅有单相交流励磁,其余励磁方法均需要增加绕组或改变绕组连接方式,不适用于当前广泛使用的航空三级式同步电机。 相似文献
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This paper investigates the problem of fault detection (FD) for discrete-time switched systems. Under a dwell time constraint, a switching rule that depends on the measured output is constructed for the system. Time-varying residual generators are designed such that the switched system is asymptotically stable and also with the detection performance under this switching rule. The advantages of the proposed technique are threefold: 1) It has the advantages of both slow switching and fast switching. 2) It can extend the classic design of time-invariant residual generator. 3) It can guarantee the switched system still has the desired fault detection performance even if all subsystems are without it. This feature reduces the performance requirements for each subsystem. A numerical example illustrates the effectiveness of the proposed method. 相似文献
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In this paper, the stability problem of discrete-time systems with time-varying delay is considered. Some new stability criteria are derived by using a switching technique. Compared with the Lyapunov–Krasovskii functional (LKF) approach, the method used in this paper has two features. First, a switched model, which is equivalent to the original system and contains more delay information, is introduced. It means that the criteria obtained by using the LKF method can be regarded as stability criteria for the switched system under arbitrary switching. Second, when the switching signal is known, the stability problem for the switched model under constrained switching is considered and piecewise LKFs are adopted to obtain stability criteria. Since constrained switching is less conservative than arbitrary switching if the switching signal is known, one can know that the obtained results in this paper are less conservative than some existing ones. Two examples are given to illustrate the effectiveness of the obtained results. 相似文献
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Qunxian Zheng Hongbin Zhang Youzhu Ling Xingzhong Guo 《Journal of The Franklin Institute》2018,355(3):1156-1175
This paper investigates the mixed H∞ and passive control problem for a class of nonlinear switched systems based on a hybrid control strategy. To solve this problem, firstly, using the Takagi–Sugeno (T–S) fuzzy model to approximate every nonlinear subsystem, the nonlinear switched systems are modeled as the switched T–S fuzzy systems. Secondly, the hybrid controllers are used to stabilize the switched T–S fuzzy systems. The hybrid controllers consist of dynamic output-feedback controllers for every subsystem and state updating controllers at the switching instant. Thirdly, a new performance index is proposed for switched systems. This new performance index can be viewed as the mixed weighted H∞ and passivity performance. Based on this new performance index, the weighted H∞ control problem and the passive control problem for switched T–S fuzzy systems via the hybrid control strategy are solved in a unified framework. Together the multiple Lyapunov functions (MLFs) approach with the average dwell time (ADT) technique, new design conditions for the hybrid controllers are obtained. Under these conditions, the closed-loop switched T–S fuzzy systems are globally uniformly asymptotically stable with a prescribed mixed H∞ and passivity performance index. Moreover, the desired hybrid controllers can be constructed by solving a set of linear matrix inequalities (LMIs). Finally, the effectiveness of the obtained results is illustrated by a numerical example. 相似文献
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《Journal of The Franklin Institute》2022,359(1):104-122
In this note, we will devote to investigate the stability of discrete-time switched positive linear time-varying systems (PLTVSs). Firstly, a new asymptotic stability criterion of discrete-time PLTVSs is obtained by using time-varying copositive Lyapunov functions (TVCLFs) and this criterion is then extended to the switched case based on the multiple TVCLFs. Furthermore, the sufficient conditions are derived for stability of discrete-time switched PLTVSs with stable subsystems by means of function-dependent average dwell time and function-dependent minimum dwell time. In addition, the stability sufficient conditions are drawn for the switched PLTVSs which contain unstable subsystems. It is worth noting that the difference of TVCLFs and multiple TVCLFs are both relaxed to indefinite in our work. The theoretical results obtained are verified by two numerical examples. 相似文献
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全文以自行车发电前景为背景,介绍了一新型机械发电装置设计的过程及内容。探讨了自行车发电的研究意义、设计了新型自行车发电机机械结构部分的机构与连接方式,分享了该机械发电装置的特性及优点。 相似文献
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Malolactic fermentation (MLF) is a process in winemaking responsible for the conversion of l-malic acid to l-lactic acid and CO2, which reduces the total acidity, improves the biological stability, and modifies the aroma profile of wine. MLF takes place during or after alcoholic fermentation and is carried out by one or more species of lactic acid bacteria (LAB), which are either present in grapes and cellars or inoculated with malolactic starters during the winemaking process. Although the main bacterium among LAB used in commercial starter cultures for MLF has traditionally been Oenococcus oeni, in the last decade, Lactobacillus plantarum has also been reported as a malolactic starter, and many works have shown that this species can survive and even grow under harsh conditions of wine (i.e., high ethanol content and low pH values). Furthermore, it has been proved that some strains of L. plantarum are able to conduct MLF just as efficiently as O. oeni. In addition, L. plantarum exhibits a more diverse enzymatic profile than O. oeni, which could play an important role in the modification of the wine aroma profile. This enzymatic diversity allows obtaining several starter cultures composed of different L. plantarum biotypes, which could result in distinctive wines. In this context, this review focuses on showing the relevance of L. plantarum as a MLF starter culture in winemaking.How to cite: Brizuela NS, Tymczyszyn E, Semorile LC, et al. Lactobacillus plantarum as a malolactic starter culture in winemaking: a new (old) player? Electron J Biotechnol 2019;38. https://doi.org/10.1016/j.ejbt.2018.12.002. 相似文献
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《Journal of The Franklin Institute》2022,359(11):5619-5633
This paper aims at the problem of exponential stability for switched linear impulsive time-varying system. By constructing two different switched discretized Lyapunov functions, some new sufficient conditions ensuring the global exponential stability of switched linear impulsive time-varying system are provided, which can be employed to the case when all subsystems are unstable. Furthermore, we apply theoretical results to the consensus of multi-agent system with switching topologies. Finally, numerical examples demonstrate the effectiveness of given results. 相似文献
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针对高压电机起动过程中的电网电压凹陷,以及电网枢纽点的母线电压波动等电能质量问题,提出了一种基于PLC调控自给直流励磁磁阀式可控电抗器的新型高压电机软起动方式。该方法克服了传统软起动方式装置体积大,谐波较大,对环境要求高,可靠性低,价格昂贵等缺点。结合自励式磁控软起动器基于恒流起动的控制策略,开发出基于16位单片机（Intel 80C196KC）和可编程逻辑控制器（PLC,Siemens S7-200）相结合的软起动器控制装置。 相似文献
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Shipei Huang Zhengbing Yan Guoqiang Zeng Zhengjiang Zhang Zhiliang Zhu 《Journal of The Franklin Institute》2019,356(6):3398-3418
This paper investigates the finite-time stabilization for a class of upper-triangular switched nonlinear systems, where nonlinearities are allowed to be lower-order growing. Due to the special structure of the considered system, the presented methods for lower-triangular switched nonlinear systems in the literature can not be directly utilized. To solve the problem, a state feedback control law with a new structure is designed to guarantee the global finite-time stability of the closed-loop system under arbitrary switching signals by using the recursive design approach and the nested saturation method. A simulation example is provided to show the effectiveness of the proposed method. 相似文献