基于组件的加权组合错误注入测试方法

在传统错误注入方法的基础上,结合组合变异测试技术,提出一种面向组件的错误注入加权组合测试方法。对组件环境的注入条件设置加权因子,在组件集成测试系统平台下面向第三方组件进行注入测试,自动生成XML格式的测试监控日志。实验结果表明,该方法能依据组件的软件环境发现并分析从高风险到低风险的组件漏洞。     

基于阵列涡流技术的裂纹特征量研究

阵列涡流传感器能够实现导电材料的大面积高速扫描。不同走向的裂纹对线圈间互感的影响是不同的,因此,测量线圈间的互感能够获得更多的缺陷信息。利用ANSYS软件对横向和纵向裂纹进行了三维有限元仿真,得到了相应的阵列涡流敏感线圈感应电动势幅值变化曲线。仿真结果表明:通过测量线圈间的互感,可以实现对裂纹长度和方向等特征量的检测。     

博物馆智能投币控制系统设计

主要介绍了博物馆智能投币系统设计的具体方案。其适用于无人操作以投币方式触发控制周边设备。主要通过涡流传感器对投入硬币币值的检测及真假币判断,并由此产生相关控制信号来模拟开关动作或控制周边强电设备,使游客能够自主参与各种互动环节。     

基于定子电流小波变换的感应电机速度估计算法的研究

提出一种基于齿槽谐波检测的转速估计算法。首先对感应电机定子电流进行小波变换,得到谱后再利用脊线检测算法提取瞬时频率,然后根据齿槽谐波频率估计转速。将该算法在感应电机无速度传感器直接转矩控制系统中进行了仿真,仿真结果表明,使用小波变换的估计算法不受电机参数的影响,明显提高了电机的转速估计精度,并且在整个转速范围内有效,从而也解决的了在低速范围内,转速估计精度低的问题。     

三相光伏并网电流型PWM逆变器的研究

基于三相电流型PWM逆变器装置,将直接电流控制方法应用于该逆变器中,设计了一套1kW实验装置。通过仿真分析和实验验证表明,该方法不仅实现了逆变器网侧电流正弦化并与网侧电压同相位,而且实现了直流侧电压宽范围调节,提高了系统动态性能,更适合于光伏并网。     

大功率LED智能化照明控制系统设计

在绿色照明领域,既要体现节能,又要具备较高的光效,大功率LED驱动设计显得越来越重要。针对大功率LED的特性,研究设计了适用于不同参数指标的白光LED的驱动与控制系统。该系统以单片机C8051F040为核心,结合外围电路,用数字控制技术代替模拟电路控制,对大功率LED的恒流驱动电流进行高精度控制,以及对LED亮度进行自动调节控制,实现了多种大功率LED智能化照明。     

Black‐box position and attitude tracking for underwater vehicles by second‐order sliding‐mode technique

In this work we address the tracking control problems for autonomous underwater vehicles (AUVs). The proposed solution is based on the variable structure systems (VSS) theory and, in particular, on the second‐order sliding‐mode (2‐SM) methodology. The tuning of the controller is carried out via black‐box approach, dispensing with the knowledge of the actual AUV parameters, by simply progressively increasing a single gain parameter. The presented stability analysis includes explicitly the unmodelled actuator dynamics and the presence of external uncertain disturbances. The good performance of the proposed scheme is verified by means of simulations on a 6‐DOF AUV. Copyright © 2009 John Wiley & Sons, Ltd.     

High‐efficiency red‐phosphorescent organic light‐emitting diode with the organic structure of 2‐TNATA/Bebq2:SFC‐411/SFC‐137

Abstract— High‐efficiency and simple‐structured red‐emitting phosphorescent devices based on the hole‐injection layer of 4,4′,4″‐tris(2‐naphthylphenyl‐phenylamino)‐triphenylamine [2‐TNATA] and the emissive layer of bis(10‐hydroxybenzo[h] quinolinato)beryllium complex [Bebq²] doped with SFC‐411 (proprietary red phosphorescent dye) have been researched. The fabricated devices are divided into three types depending on whether or not the hole‐transport layer of N,N′‐bis(1 ‐naphthyl)‐N, N'‐diphenyl‐1,1′‐biphenyl‐4,4′‐diamine [NPB] or the electron‐transport layer of SFC‐137 (proprietary electron transporting material) is included. Among the experimental devices, the best electroluminescent characteristics were obtained for the device with an emission structure of 2‐TNATA/Bebq²:SFC‐411/SFC‐137. In this device, current density and luminance were found to be 200 mA/cm² and 15,000 cd/m² at an applied voltage of 7 V, respectively. Current efficiencies were 15 and 11.6 cd/A under a luminance of 500 and 5000 cd/m². The peak wavelength in the electroluminescent spectral distribution and color coordinates on the Commission Internationale de I'Eclairage (CIE) chart were 628 nm and (0.67, 0.33), respectively.     

Highly efficient switched‐mode transmitter using a current mode class‐D RF amplifier

This article presents a switched‐mode transmitter architecture using a current mode class‐D (CMCD) amplifier. To achieve high average efficiency for a modulated signal the envelope of the complex baseband signal is transformed into pulses such that the CMCD amplifier is operated either at its peak efficiency or completely switched off. The CMCD amplifier has been designed based on single‐tone active harmonic load‐pull measurements to achieve a power‐added efficiency (PAE) of 61.5% with 25 W output power at 900 MHz using LDMOS FETs. Removing the losses of the demodulation filter and of the amplifier a 10% higher efficiency than in an ideal class‐B amplifier can be obtained for burst‐mode operation with a peak‐to‐average power ratio of 10 dB. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

A current‐mode tunable low‐supply‐voltage ring oscillator

A new circuit topology using a current‐mode low‐pass filter for sinusoids has been presented. The technique is relatively simple, in the proposed circuit, only three identical current‐mode low‐pass filters are connected to each other to realize the small signal path. No external passive components are required except for three capacitors. When compared with LC oscillators, the die area of this work, without inductors, is much smaller. When compared with voltage‐mode ring oscillators, the supply voltage of this work is much lower. As a particular example, a 2.4 GHz, 1.2‐V power supply, 5‐mW sinusoidal oscillator is demonstrated. The oscillation frequency is tuned by the value of that three capacitors, over ～900 MHz, and the tuning range is 37.5%. The phase noise results in ?94 and ?120 dBc/Hz at 1 and 10 MHz from the carrier, respectively. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.