介绍了四川大学"电工技术基础"课程开展的混合式教学改革,突出"以学为中心"的教育理念,将传统课堂教学和网络教学的优势相结合,通过设计线上线下的教学环节、合理分配教学内容,综合运用超星泛雅平台进行课前、课中、课后及课程评价的整体设计,进行混合式教学模式的探索与实践,实现线上线下教学的有机结合,提升了教学效果.

在新工科人才培养的新要求下,工程实践教学改革的目标是培养更多卓越的工程创新型人才.实践设计是新型人才创新实践能力培养的重要载体,为解决课堂知识侧重基本理论与创新思维人才培养之间的矛盾.四川大学电路实验室将基于LABVIEW可视化图形编程软件开发的具有信号分析、数据采集、数据处理、数据保存、数据图形化显示等功能的实验教学系统应用在本科电路实验教学当中.通过固纬GDS-1000B、AFG-2225、科睿源KA3010P硬件平台以及LABVIEW软件,对串联谐振以及单管放大电路的电压、频率以及波形数据进行采集和处理,实现了谐振频率的自主分析和波形数据的有效存储.实验结果表明该系统性能稳定,具有较高的测量精度,并且可以应用到其他实验以及科研项目当中,具有较好的移植性.

针对多重信号分类算法(multiple signal classification,MUSIC)在低信噪比、小快拍数或信源角度相近等复杂环境下波达方向(Direction of arrival,DOA)估计性能严重下降这一问题,提出一种新的基于谱函数二阶导数的DOA估计算法.利用MUSIC空间谱函数的二阶导数能在原始波达方向周围产生负峰值的特性,通过对二阶导数空间谱进行负峰值搜索实现DOA估计.实验结果表明,在低信噪比、小快拍数或信源角度接近的情况下,该方法能准确进行DOA估计,且性能明显优于经典MUSIC算法.

传统的二次型Boost功率因数校正变换器只能实现升压输出,在一定程度上限制了其在LED驱动电源中的应用.基于二次型Boost变换器提出了一种Boost型无频闪谐振降压式LED驱动电源,并分析了其工作原理及特性.该LED驱动电源利用一个有源开关管将二次型Boost变换器与一个谐振网络进行整合,可实现低电流纹波和降压变换输出.最后,搭建了一台84 W的实验样机,最高效率达到92.88%,验证了所提方法的正确性及可行性.

全面推进课程思政建设是落实立德树人根本任务和将社会主义核心价值观融入教育教学全过程的重要举措.针对"电工技术基础"课程的教学特点和教学内容,探索课程与思政教育的结合方式,提炼课程蕴含的思政元素,将道德规范、社会主义核心价值观、科学知识、思维方式等有机融入课堂教学中,建立全过程、全方位的课程思政体系.

工科对于动手能力培养的课程主要集中在实验课程。在新工科教学改革的大环境下，如何最大程度地发挥实验课程的作用？如何以学生为中心，发挥学生学习的主观能动性等问题是亟待工科实验授课教师解决的问题。本文介绍了对大学一年级专业选修课程《电工电子测量技术与实验》课程进行的教改，在不减少验证性实验的基础上增加了设计性实验内容；改变了评分标准，提升了学生自主学习的积极性；开放设计题目，将学生的想象力和创新思维能力融入到课程设计中。为新工科思维下，实验教学改革做了一定的探索。

作者基于超星"泛雅"平台进行"电工技术基础"SPOC课程教学模式探索,围绕"以学为中心",分别从课前、课中、课后以及评价进行线上教学设计,开展全新的线上教学活动,保证在线学习与线下课堂教学质量实质等效.

信息技术对教育的影响日趋明显,大力推进智慧课堂建设已成为课堂教学革命的发展方向.本文结合“电工技术基础”课程基于智慧课堂的教学改革,讨论如何充分利用智慧教学环境,把教育信息技术、先进的教学模式在课程教学中进行深度融合,构建智慧课堂,促进学生参与教学全过程,进一步深化“以学为中心”的教学改革.

传统教学偏重理论知识的学习和验证性实验,而新工科建设和发展需要培养创新型、综合型人才,强调将所学理论知识应用于实际工程实践的动手能力和创新能力的培养.为此,我们对大学一年级电气专业选修课程《电工电子测量技术》进行教学改革,改变了以前理论课和实验课各自独立的教学方式,课程的教学过程遵循理论授课—实验验证—设计实验—设计实验的实验验证-完成实验报告这样一个过程,将所学知识经历了从理论到实践,再到理论,再到实践的两个循环,培养了学生理论知识的实践应用能力,实现了理论和实验课程的融合.

基于探究式学习的"大班授课小班研讨"是一种以学生为主体,以活动为中心的教学模式.结合四川大学"电工技术基础"大班授课小班研讨的探究与实践,本文讨论了如何开展基于探究式学习的"大班授课小班研讨"教学,如何促进学生在学习中的主动性和自我参与意识,最后介绍了在"大班授课小班研讨"教学实践中的体会、问题及展望.

In the power system,as the premise of harmonic suppression,harmonic detection is necessary to improve power quality.According to problems of the main harmonic detection methods,such as low accuracy of instantaneous reactive power theory,spectrum leakage,fences phenomenon existed in Fourier transform,and complicated computation,slow analysis speed,poor real-time performance of wavelet packet theory,we presented an improved wavelet transform harmonic detection method combined wavelet transform and wavelet packet.Only for a specific frequency band harmonic detection,the time-frequency characteristics of wavelet and wavelet packet were used to extract the frequency of component and calibrate the start and stop times of the specific harmonic frequency.The amount of computation has been reduced and the real-time performance of harmonic detection has been improved with this method.The Matlab simulation results show that the proposed method detects the harmonic components effectively and improves the detection speed.The timeliness of power harmonic detection based on the improved wavelet transform has been verified.

This paper proposes a multi-scale special transformer power demand forecasting based on the continuous wavelet analysis,and aiming at the special transformer users' average monthly electricity consumption,the wavelet decomposition accounted for 1 to 12 months of different scales is performed and then fitting superposition is done the gray model to estimate the electricity consumption in the next month.At the same time,the paper analyzes the characteristics of the electric signal reflected by different wavelet scales,and gives the prediction error of the model.The actual prediction proves that the difference between the actual power consumption and the forecasted power consumption of the transformer for a special user in South China power grid since 2014,and the average prediction error is 0.014 5.

Measurement equipment failure and environmental factors often generate noise in the detection of electric power system.Therefore,the signals which we collected suffer from a certain degree of noise pollution.It reduces power quality of electric power system,and wavelet transform can lead to a great benefit in signal de-noise.Hence,it has great significance for electric signal denoising to make use of wavelet transform.The purpose of this paper is to comparatively analyze the advantage of wavelet transform,conduct several times primary wavelet transform and couple back problems in electric power system detection.after that,the improvement of wavelet de-noising is conducted by subprime wavelet transform,and multiple threshold processing method is also analyzed and utilized.

对四旋翼飞行器飞行姿态的稳定控制问题进行了分析,设计了基于STM32系列微控制器的稳定控制系统.STM32以ARM Cortex-M3为内核,拥有强大的运算能力,作为四旋翼飞行器的飞行姿态控制器的主控芯片.采用四元素融合滤波算法对陀螺仪和电子罗盘等多传感器采集的数据进行飞行姿态解算.结合串级PID控制算法实现四旋翼飞行姿态控制系统设计.仿真及实验结果表明该控制系统符合设计要求,达到了对四旋翼飞行器飞行姿态稳定控制的目的.验证了基于STM32的串级飞行姿态控制的有效性,为后续研究奠定了基础.

With the rapid development of the Internet of things(IoT),the Ethernet has become an important module of the embedded sys-tem.For lots of the cheap microcontrollers without Ethernet module,this paper uses the CH395 chip to connect the SPI interface of the dsPIC33 microcontroller to accomplish the function of the Ethernet.This design is easy,and the occupation of resources is very few,so it is a reliable design.

随着分布式电源(Distributed Generation,DG)在配电网中被越来越多的应用,探究分布式电源的选址定容问题成为研究的热点.为降低配电网负荷及DG出力时序特性对DG规划的影响,文章分析了负荷和DG出力时序特性曲线,建立了多目标数学模型,利用层次分析法对多目标函数处理,采用遗传—模式搜索混合智能算法(IGABPS)进行一年全时段寻优求解.最后采用IEEE33节点系统对方案进行验证,算例结果表明了考虑时序特性的规划方案更能真实反映配电网的实际运行情况.

In view of the advantages and development situation of OLED,the working principle of OLED is introduced.An OLED driver system based on BF531 processor is designed.The function of each hardware module and the design technological process of software are expounded in detail.The selection of some pivotal devices is explained.Finally,the performance and application value of this driver system are estimated according to the effect of OLED displayer shown before.

Microchip Graphics Library is a small size,high portability and less resource consumption embedded Graphical User Interface.In the view of these features of MGL,an embedded system based on PIC32MX microprocessor is devised.And then,the porting process and usage on this platform of MGL are researched in this paper.Finally,a human computer interaction system is designed and utilized in a DC power supply with a desired consequent.

DVB-C system hardware realization method and the DVB-C encoder based on the standard DVB digital TV communication system are introduced in this paper.The structure of the coder is realized based on FPGA,including the RS code and convolution,and the simulation result of the two modules are proposed.This design schemes meeting DVB-C standard,then shows the code's simulation results.

Fiber Bragg grating (FBG) sensors used for detecting interface damage of steel-concrete composite bridge deck model was tested. The interface damage includes slippage and disengage. The tests cover three stages: dead load tests, fatigue tests(3 × 106 cycles) and destructive tests. In the fatigue test stage, dynamic loads with equal amplitude harmonic wave were added. During the destructive test stage, slippages and disengages occurred one after another and were measured by the FBG sensors. The critical strain values of the two kinds of interface damage were detected. The experimental results and the data obtained in the three stages show that in the first two stages no damage occurs, strain data measured by FBG sensors are consistent with those measured by resistance gauges and the FBG sensors can trace the development processes of the damage. Until the bridge deck model is totally damaged, the FBG sensor system remains proper working status and the data measured are consistent with the result inspected by eye. The results show that interface damage can be detected successfully by the FBG sensing. This work is useful for the structural health monitoring and the optimum design of composite structure.