Simulation on a Car Interior Aerodynamic Noise Control Based on Statistical Energy Analysis

How to simulate interior aerodynamic noise accurately is an important question of a car interior noise reduction. The unsteady aerodynamic pressure on body surfaces is proved to be the key effect factor of car interior aerodynamic noise control in high frequency on high speed. In this paper, a detail statistical energy analysis （SEA） model is built. And the vibra-acoustic power inputs are loaded on the model for the valid result of car interior noise analysis. The model is the solid foundation for further optimization on car interior noise control. After the most sensitive subsystems for the power contribution to car interior noise are pointed by SEA comprehensive analysis, the sound pressure level of car interior aerodynamic noise can be reduced by improving their sound and damping characteristics. The further vehicle testing results show that it is available to improve the interior acoustic performance by using detailed SEA model, which comprised by more than 80 subsystems, with the unsteady aerodynamic pressure calculation on body surfaces and the materials improvement of sound/damping properties. It is able to acquire more than 2 dB reduction on the central frequency in the spectrum over 800 Hz. The proposed optimization method can be looked as a reference of car interior aerodynamic noise control by the detail SEA model integrated unsteady computational fluid dynamics （CFD） and sensitivity analysis of acoustic contribution.

Active Noise Control of the Heavy Truck Interior Cab

In order to control the noise of the heavy truck interior cab effectively, the active noise control methods are employed. First, an interior noise field test for the heavy truck is performed, and frequencies of interior noise of this vehicle are analyzed. According to the spectrum analysis of acquired noise signal, it is found out that the main frequencies of interior noise are less than 800Hz. Then the least squares lattice （LSL） algorithm is used as signal processing algorithm of the controller and a closed-loop control DSP system, based on TMS 320VC5416, is developed. The residual signal at driver＇s ear is used as feedback signal. Lastly, the developed ANC system is loaded into the heavy truck cab, and controlling the noise at driver＇ s ear for that truck at different driving speeds is attempted. The noise control test results indicate that the cab interior noise is reduced averagely by 0.9 dBA at different driving speeds.

Nonlinear Control of Interior PMSM Using Control Lyapunov Functions

In this paper, we introduce a non-linear torque control for an interior permanent-magnet synchronous motor (IPMSM). The nonlinear control is based on a Control Lyapunov Function (CLF) technique. The proposed stabilizing feedback law for the IPMSM drive is a damping control method and is shown to be globally asymptotically stable. The CLF method takes the system nonlinearities into account in the control system design stage. Such nonlinearities are due to the cross coupling between the q and the q currents in addition to the system parameters like the inductances and the flux linkages. The complete IPMSM drive incorporating the proposed CLF has been successfully simulated in a plant model for both motor and inverter. The performance of the proposed drive is investigated in simulation at different operating conditions. It is found that the proposed control technique provides a good torque control performance for the IPMSM drive ensuring the global stability. In later work, we are planning to investigate other phenomena such as magnetic saturation, nonlinear loads, mechanical friction and flexibilities.

基于RBF神经网络的汽车内饰皮革智能切割系统设计

随着汽车用皮革的迅速发展,开发一套满足汽车内饰皮革生产需求的智能切割系统具有重要意义。本文简述了汽车内饰皮革切割系统的发展,构建了基于径向基函数(Radial Basis Function,RBF)神经网络的汽车内饰皮革智能切割系统,介绍了系统主要硬件配置选型和软件的设计,提出了基于RBF神经网络PID(Proportional Integral Derivative,比例-积分-微分)控制算法;通过搭建试验平台,测试汽车内饰皮革智能切割系统的可行性、切割精度与效率。结果表明,该系统能够较好地满足汽车内饰皮革切割方面的需求。

高速列车包间噪声特性及降噪方案设计验证

针对高速列车包间噪声问题及降噪措施进行了相关研究。首先,通过线路试验分析了高速列车包间噪声特性,包括噪声频谱、声源识别和声品质,掌握了包间中心与铺面上方测点的噪声差异,明确了包间噪声控制目标;其次,基于统计能量分析方法建立了高速列车包间噪声预测模型,并进行了试验验证,开展了包间声能量贡献分析,确定了降噪方案设计指标,进而对车体进行了隔声方案优化设计;最后,通过包间噪声的迭代预测,确定了车体降噪方案的可行性,并进行了线路试验验证。结果表明,采用笔者设计的降噪措施,包间噪声总值降低了3.2 dB(A),包间原本较高的响度和粗糙度得到明显控制,尖锐度也略有降低,声品质得到了优化。

基于延迟校正扩张状态观测器的内置式永磁同步电机电流控制策略

高速电驱动场合会受到开关频率的限制,低载波比特性凸显,由此引起的控制延迟问题影响了内置式永磁同步电机(IPMSM)矢量控制系统性能。基于扩展电动势的建模方案能够获得IPMSM的对称化模型,有利于离散化分析和设计,以提升低载波比运行性能。扩张状态观测器(ESO)能够实现扩展电动势和扰动的集总观测,然而低载波比延迟问题影响了估算性能。该文在离散域中分析延迟影响,设计和对比研究了几种延迟影响抑制方案,即延迟校正扩张状态观测器,提升了估计精度。基于此,设计了IPMSM离散域电流控制方案,显著提升了电流响应特性。通过电动汽车驱动实验平台验证了该文的分析和设计。

基于EKF的IPMSM无位置传感器控制估计误差补偿方法

在基于扩展卡尔曼滤波(EKF)法的内置式永磁同步电机无位置传感器控制系统中,电机转速和转子位置的准确估计十分重要。针对相电流增益误差导致的转速和转子位置估计精度下降的问题,提出一种位置估计误差补偿方法。首先,理论推导得出,在扩展卡尔曼滤波器估算过程中,相电流增益误差会使估计转速及转子位置以二倍工频的频率振荡。其次,设计了一种新型结构扩展卡尔曼滤波观测器,即在传统扩展卡尔曼滤波观测器的基础上增加增益误差系数求解环节,以此来降低相电流增益误差引起的估计转速及转子位置的脉动,提高了估计精度。最后,仿真和试验验证了所提补偿方法的可行性。

综合医院装配式内装修施工技术管控要点

以某医院项目的装配式装修为例,结合在施工过程中遇到的问题,从科学合理的界面划分及施工方案,部品、部件的选型,BIM技术的运用,样板间的实施引领等几个方面分析装配式装修在施工过程的技术管控要点,总结经验,为类似医院工程的装配式内装修设计及施工提供参考。

基于物联网的车内环境监测与通风系统设计

为解决车辆长时间在太阳直射以及气温高时,车内门窗紧闭会导致室内空气不流通的问题,文章设计一款基于物联网的车内环境监测与通风系统。该系统包括数据采集端、执行控制端、远程遥控端,通过车内环境传感器、车载雨量感应器等采集数据,将数据传输给核心控制器进行数据处理,AVR单片机通过控制车窗升降的电机,并运用远程遥控端实现远程控制车窗开启或关闭,实现车内环境监测与通风功能。该系统具有结构简单、实用性强等技术特点。

蓬莱阁仿古建筑装饰工程施工质量控制要点研究

蓬莱阁作为中国古代四大名楼之一,自身的建筑类别十分丰富,既有六大建筑单体组成的古建筑群,又有蓬莱水城和周围配套建设的仿古建筑群。这些建筑既有增建和修缮,又有湮灭和复建,历经千年,形成目前的规模。为追求建筑内外观的形神合一,保持建筑内部装饰的中式风格,质量控制尤为重要。文章总结了工程实践中现场监管的经验,提出了一套仿古建筑装饰工程施工质量控制要点,希望为日后的工程监管提供参考。

高校教学楼照明控制系统节能改造方案探讨及应用

建设年代久远的高校建筑在照明节能控制上有诸多问题,本文通过分析高校照明现状问题,结合高校照明按不同时段使用的特点,给出智能照明控制和人体感应控制相结合的照明控制思路,并以某高校教学楼室内照明改造设计案例进行探讨。

内嵌式永磁同步电机矢量控制系统弱磁控制研究

提高变桨电机的稳态和动态控制性能,保证在不同风况及母线电压跌落的情况下维持电机高速运行的稳定性尤其重要。分析了内嵌式永磁同步电机的模型及约束条件,结合永磁同步电机的应用特点,基于SVPWM的矢量控制与电压外环的双电流弱磁控制策略,设计了矢量控制和弱磁控制系统模型并进行了仿真。基于该控制系统模型搭建了实验平台,对不同直流母线电压下矢量控制与弱磁控制的性能进行了对比测试和分析,验证了模型设计的合理性,实现了扩速性能。目前,该控制系统已应用于风机变桨伺服控制系统,具有较高应用价值。

相温子库传热优化及柠檬贮藏效果

为研究子库传热面积、材料、对流风速和厚度对子库传热的影响,以及优化子库传热对柠檬保鲜效果的影响。通过增大子库传热面积、提高对流风速等方法,确定子库传热的主要影响因素,并对其进行优化试验和对柠檬进行贮藏效果研究。结果表明:子库传热面积对子库传热影响最为显著,其次为子库对流风速;柠檬贮藏效果研究结果表明,相温贮藏相较于普通冷藏能明显抑制柠檬果皮变黄和失重现象,并减缓维生素C、总可溶性固形物等营养物质的流失,优化子库传热后能进一步提升相温贮藏效果。

城市轨道车辆车内噪声的来源及控制

本文根据轨道车辆噪声源的不同共介绍了6种噪声,并着重介绍了在车辆运行时、制动时、静止时对车内噪声贡献最大的三种噪声来源(轮轨噪声、制动噪声、空调噪声)。通过对三种噪声的产生、传播途径及控制方式等方面的探究,得出可以通过主动降噪(对制动盘及闸片进行表面处理、在轨道及车轮上增加阻尼、优化通风管道结构等)降低车内噪声。同时,在声音传播过程中降低制动噪声级轮轨噪声的方式主要有:加装车底次地板、选用塞拉门、加装隔音吸引防寒材、喷涂阻尼浆等。

Linear Programming for Optimum PID Controller Tuning

This work presents a new methodology based on Linear Programming (LP) to tune Proportional-Integral-Derivative (PID) control parameters. From a specification of a desired output time domain of the plant, a linear optimization system is proposed to adjust the PID controller leading the output signal to stable operation condition with minimum oscillations. The constraint set used in the optimization process is defined by using numerical integration approach. The generated optimization problem is convex and easily solved using an interior point algorithm. Results obtained using familiar plants from literature have shown that the proposed linear programming problem is very effective for tuning PID controllers.

软土地基升压站场地建设方案比选

在变电站建设过程中,洪水位较自然地面高程相差较大是普遍存在的场地问题。为保证变电站不受洪水位影响,一般会采取相应防洪防涝措施、抬高场地与构筑物的室内地坪和底座等方式进行地基处理。以国能长源荆州市纪南镇100MW渔光互补光伏发电项目为例,从占地面积、施工难度、运行便利等方面的优缺点及经济性进行方案比选,得出了最优的推荐方案,可供同类工程参考。

改进高频脉振电压注入的IPMSM无传感器控制

为解决传统静止坐标系高频脉振电压注入法由直流偏置导致的估计转子位置不准确的问题,在此提出了一种基于改进静止坐标系高频脉振电压注入的内置式永磁同步电机(IPMSM)无传感器控制方法。该方法仅使用β轴定子电流估计转子位置和转速,因此解决了直流偏置问题。首先,采用四阶广义积分提取高频电流,四阶广义积分在谐振频率处具有单位增益和零相移,保证了提取高频电流的准确性。然后,利用改进的二阶广义积分获得包含转子位置信息的正交信号,并且可以精确补偿信号处理过程中低通滤波器产生的相移和幅值衰减。最后,在2 kW IPMSM驱动平台上验证了算法的有效性。

车内空气质量控制标准及半挥发性有机物研究探讨

近年来,随着车辆保有量的不断上升,汽车污染带来的空气污染和健康影响不断加深,人群对车内空气质量控制的需求不断提高,车内空气质量问题也越来越多受到人群的关注,本文针对车内空气质量控制,梳理并阐述目前国内外车内空气质量控制标准以及我国车内饰污染物质量控制标准,总结并分析车内空气中半挥发性有机物样本采集方法及重点关注物质.结果表明:①目前中国、日本、韩国以及俄罗斯等国家车内空气质量控制标准中挥发性有机物是重点关注指标且其限值具有差异,除日本外,其他国家暂未将半挥发性有机物纳入控制标准.②我国车内饰质量控制标准指标中有机物指标占所有指标的66.90%,其中半挥发性有机物指标占有机物指标的30.94%,且多为增塑剂、阻燃剂类等对人体健康具有危害的物质.③车内空气半挥发性有机物研究涉及气态、颗粒态以及粉尘样本,超过66.67%的样本采用主动采样法进行收集.研究中关注的重点物质包括溴化阻燃剂、磷系阻燃剂、邻苯二甲酸酯、全氟化合物等阻燃剂和增塑剂类物质,其研究次数占所有物质研究次数的88.14%.针对车内空气质量管理提出两点建议:①在现有车内空气质量管理标准与技术指南的基础上,我国需要扩大质量控制指标范围,适当加入阻燃剂、增塑剂等半挥发性有机物控制指标;②完善车内空气质量样品采集技术指南,针对半挥发性有机物制定采样规范.

Risk Control of Transmission Line Overload for Wind-Integrated Power Systems

With the rapid development of the wind generation,uncertainties of random wind and load bring some inevitable impacts on the security of power system. Once the uncertainty causes line power to exceed its limit, line overload will occur. The paper presents the risk control of transmission line overload for windintegrated power systems. Firstly, a risk control model of line overload is proposed considering the uncertainties of loads,generator outputs and wind powers. The generation cost and security level of system associated with overload can be optimally controlled. Then path following interior point method is employed to carry out the optimal control. Finally the simulation is made on the modified IEEE-30 bus system. Results show that the risk of line overload is effectively reduced through the optimization of control variables.

Rothe’s Fixed Point Theorem and the Controllability of the Benjamin-Bona-Mahony Equation with Impulses and Delay

For many control systems in real life, impulses and delays are intrinsic phenomena that do not modify their controllability. So we conjecture that under certain conditions the abrupt changes and delays as perturbations of a system do not destroy its controllability. There are many practical examples of impulsive control systems with delays, such as a chemical reactor system, a financial system with two state variables, the amount of money in a market and the savings rate of a central bank, and the growth of a population diffusing throughout its habitat modeled by a reaction-diffusion equation. In this paper we apply the Rothe’s Fixed Point Theorem to prove the interior approximate controllability of the following Benjamin Bona-Mohany(BBM) type equation with impulses and delay where and are constants, Ω is a domain in , ω is an open non-empty subset of Ω , denotes the characteristic function of the set ω , the distributed control , are continuous functions and the nonlinear functions are smooth enough functions satisfying some additional conditions.