附加场强度对低工况AF-MPDT性能的影响

附加磁场强度与位形是大功率磁等离子体动力推力器(Applied Field Magnetoplasmadynamic Thruster, AF-MPDT)重要工作参数之一。为验证附加磁场强度对低工况下AF-MPDT性能的影响,采用北京控制工程研究所联合北京航空航天大学研制的100 kW级AF-MPDT原理样机,利用推力靶测量系统进行高温震动环境下的推力测量,针对不同附加磁场强度(30～230 mT)下的推力器开展中低功率性能研究实验。实验结果表明,在一定范围内,增加磁场强度可提升低工况下推力器推力、比冲、放电电压及效率等性能指标,并且放电电流越大,性能提升效果越明显。分析表明,低工况下AF-MPDT推力、比冲与磁场强度的平方根呈线性关系;推力器放电电压与磁场强度呈线性关系;推力器效率随磁场强度增强而增加,最终达到相应工况下的极限。

Asynchronous Observer Design for Switched Linear Systems: A Tube-Based Approach

This paper proposes a tube-based method for the asynchronous observation problem of discrete-time switched linear systems in the presence of amplitude-bounded disturbances.Sufficient stability conditions of the nominal observer error system under mode-dependent persistent dwell-time(MPDT)switching are first established. Taking the disturbances into account, a novel asynchronous MPDT robust positive invariant(RPI) set and an asynchronous MPDT generalized RPI(GRPI)set are determined for the difference system between the nominal and disturbed observer error systems. Further, the global uniform asymptotical stability of the observer error system is established in the sense of converging to the asynchronous MPDT GRPI set, i.e., the cross section of the tube of the observer error system. Finally, the proposed results are validated on a space robot manipulator example.

光伏电站中电缆压降对最大功率点跟踪系统的影响分析

目前光伏发电已成为我国发电系统的重要组成部分之一,其中最大功率点跟踪(MPPT)作为提高整个光伏发电站效率的核心技术尤显重要。本文根据光伏发电站的系统结构,基于Matlab/Simulink平台搭建仿真模型,结果表明电缆压降对光伏发电站最大功率点跟踪系统有影响。因此,可以通过调整直流电缆等效内阻提高MPPT的工作效率,从而使整个光伏电站的效率也得到进一步提高。