Cascaded H-Bridge (CHB) converter has high output power quality, which can be used in energy storage grid connected systems to control charging and discharging of batteries. But this system contains a large number of switching devices and energy storage batteries, increasing the probability of failure. The traditional fault-tolerant control is not suitable when the state-of-charge (SOC) initial values of the battery modules are not the same. Therefore, a new control strategy is proposed in this paper, which only needs to inject zero-sequence voltage once and makes system control simpler and more efficient. Through MATLAB/Simulink and experiments, it has been proven that the proposed fault-tolerant control can not only maintain normal operation in the event of system failure, but also greatly improve the SOC balance speed.

储能单元作为直流微网系统重要的组成部分,关系到充放电过程中功率的合理分配和母线电压的持续稳定.然而对于含有多个分布式储能的直流微电网系统,SOC的不均衡必然会降低储能系统的可利用率,在不同工况下,为了保证系统正常稳定运行的同时能够实现储能单元SOC的快速均衡控制,首先,提出一种引入线路阻抗补偿前馈环节和动态调速因子的改进型下垂控制策略,消除分布式储能单元初始状态不一致和线路阻抗不同所带来的影响;然后,通过Matlab/Simulink搭建仿真平台实验,验证所提控制策略在不同充放电工况下运行的可行性和有效性;最后,得出结论:多种工况下相比于原有的控制策略,本文所提出的动态调速因子控制策略能够有效加快储能的均衡速度,并维持微电网系统的正常稳定运行.

A Neutral Point Clamped (NPC) type three-level inverter has the advantages of a low switch voltage and a high-quality output waveform. However, there are inherent problems, such as neutral point potential asymmetry and common mode interferences, which easily affect the symmetry of the three-phase output voltage and the safe operation of the inverter. Firstly, according to the different modulation degrees, the fluctuation of midpoint potential can be suppressed by adding an action time correction factor to the traditional space vector pulse-width (SVPWM) modulation strategy and virtual space vector pulse-width (VSVPWM) modulation strategy, respectively. Secondly, considering the suppression of common mode voltage, a new virtual space vector pulse-width (NVSVPWM) modulation strategy is proposed, which uses a set of new vector synthesis methods. Finally, the simulation and experiment prove that the NVSVPWM strategy with an action time correction factor can suppress the fluctuation of the neutral point potential and common mode voltage at the same time, and the effect is significant.

The inconsistency of the battery modules will lead to overcharging and over-discharging of the grid connected energy storage system. For the modulation strategy of cascaded H-bridge inverter, this paper proposes a new state of charge (SOC) equalization control strategy, which can quickly realize equalization control in one phase and between phases without over-modulation. The simulation results show that the new control strategy has a significant effect, which greatly improves the speed of SOC balancing compared with the traditional SOC equalization control strategy.

针对目前高等学校电气工程及其自动化专业新能源类课程存在教学内容多、各课程内容又密切相关的特点,考虑到学生学习积极性较差的现状,课题组提出了基于项目驱动的新能源课程群教学模式.课题组分析了新能源课程群各课程的特点,将各课程教学内容模块化,结合专业发展趋势设置教学项目,明确目标和分阶段任务,"以项目为主线、教师为主导、学生为主体",改变了以往"教师讲,学生听"的被动教学模式,完善了学生主动参与、自主协作、探索创新的新型教学模式.教学实践表明,基于项目驱动的新能源课程群教学模式可有效改善教学质量和提高学生的动手能力,增强学生应用所学知识解决实际问题的能力,进而提升学生的专业素养.

通用变频器功能完善、操作简单、应用广泛,但由于其高度集成化,学生只能利用它进行基本的实验操作,很难将学到的理论知识融入其中.基于Matlab仿真软件,结合三相异步电动机,搭建通用变频器的仿真教学平台,构成一个基于通用变频器—三相异步电动机的交流调速系统.通过模型的构建、参数的设置以及仿真内容的设置等多个环节,让学生将变频器涉及的重要理论知识通过仿真的分析得以验证,并结合实际工程问题进行分析,尤其是在控制策略的实施上,发挥仿真平台的优势,提高学生的电路设计、仿真分析以及解决问题的能力.

利用互联网技术开展远程实验是教学模式的一种升级,有助于提高实验设备的利用率和实验室的开放空间.提出利用交换机、网络摄像头和服务器等通信设备,构建一套基于校园网的PLC远程实验教学平台.详细介绍了远程实验的实现方案和实验网站的建设情况.通过实际应用证明,该平台具有身份识别、预约实验、远程在线实验、实验报告上传和网站维护等功能,能够满足网络化实验教学的需要,激发了学生学习兴趣,显著地改善了教学效果.

Remote simulation experiments using GPRS communication network and configuration software not only enrich the experimental techniques, but also help to improve the openness of the laboratory. This paper proposes a new technology for remote simulation experiments using a PLC as the core experimental equipment and a combination of GPRS-DTU module and KingView software. Firstly, the design idea and composition of the remote simulation experiment system are introduced. Then, the elevator monitoring system is taken as an example to introduce the research and development process of key experimental technology in detail. Finally, the actual teaching effect has proved that the technology can meet the needs of modern experimental teaching and can promote the improvement of the level of virtual simulation experiment teaching.

The three-dimensional space vector pulse width modulation(3D-SVPWM)control strategy for suppressing common-mode voltage of three-phase four-bridge inverter is analyzed.Because the common mode voltage generated from the high power convertor system is easy to damage the load such as motor,and affect the power quality of the power supply,an optimized 3D-SVPWM control strategy is proposed.Firstly,the topology of three-phase four-bridge inverter is described,and the reason of generating the common mode voltage is given.Then,according to the traditional 3D-SVPWM control strategy,two converse non-zero vectors near the reference vector are selected to replace the zero vectors.Finally,the modeling and simulation are carried out through MATLAB/Simulink and the results show that the improved control strategy is not affected by the changes of load balance status.Moreover,without changing the DC voltage utilization,the common-mode voltage can be effectively decreased to realize active suppression.

“电力拖动自动控制系统”课程改革以提升学生工程素质为目标,优化了课程内容,拓展了教学资源;教学活动中引入了基于问题、基于案例和基于项目的教学方法;建立了基于仿学研用“四位一体”的考核体系,实现了教学考一体化的设计.通过在教育部卓越工程师计划班级中试点,促进了学生工程实践能力和工程创新能力的培养.

报警器大多采用一体化结构,且往往只针对某一类型报警信号专属专用,缺乏通用性,因此基于STM32单片机设计了一款具有主、副板结构的分体式通用报警器.主板由电源电路、传感器、短信发送模块和继电器模块组成,副板带有传感器和电池电路等.主、副板之间通过PT2262/PT2272编解码芯片进行无线通信.试验证明分体式结构灵活可靠,实用性强;报警器输出接口多样,便于用户扩展,具有较强的通用性.

《电力拖动自动控制系统》课程是国内高校电气工程及其自动化专业的核心课程,是《电机学》《自动控制原理》《电力电子技术》等多门课程的结合、交叉与综合应用.课程内容涉及的系统控制对象具体,对工程实践能力要求高,是理论知识和工程实践的高度融合,也是"卓越工程师计划"和"工程专业认证"所要求的专业必备知识.

针对《直流调速系统》知识综台性强、工程应用性强、专业性强的特点,为提高学生学习兴趣,真正实现教考统一、学以致用,提出基于仿学研用的综合教考体系.教学过程中将理论学习、仿真分析、实验训练、现场应用和科研探索有机结合在一起,融入基于问题、案例和项目的教改模式,在各个环节实施相应的考核方法.通过这种新型教考体系,有效促进学生的学习热情,加强师生之间的交流互动,全面培养学生的自主学习能力、综合表达能力、实践能力、协作能力和创新能力.

学生的个性化发展正成为高校教育改革和发展的重要趋势.本文以电气工程及其自动化专业为例,提出一种自控型个性化人才培养模式.我们一方面强调要重视培养教师的个性化,另一方面要从学生利益出发主动求变,突出特色勇于创新.笔者总结了探索实践的过程,并详细介绍具体实施步骤以及取得的相关成果.

本文针对“直流调速系统”课程知识综台性强、工程应用性强和专业性强的特点,提出“以工程设计学理论、以模型仿真促实践、以科研案例析应用”的教学改革理念.我们从教学内容、教学方法和考核方法等方面设计了相应的实施方案,注重培养学生的理论分析能力、实践动手能力和科研创新能力,有效激发了学生的学习热情,提高了教学效果.

Grid synchronization is very important for reliable operation of the power system, and it is an essential technology which students or technicians need to catch. A set of experiment device has been developed to analog this process. This paper briefly introduces the experimental principle and the simulation experiment of this device, and contrasts the two simple methods for synchronous indicator. According to the actual effect, it proves that this device can fully satisfy teaching requirements.

电气控制(继电接触器控制)与PLC控制是现代化生产广泛采用的控制技术。开设相关课程有助于从事电气工程专业的学生、技师熟悉并掌握这些技能。本文分别从教学和实践两环节入手,详细介绍了课程的建设情况,并结合课程改革,提出了DIY式实践教学、校企联合培养、以赛带学等多项创新性的举措。通过实际的教学效果来看,可充分满足教学和生产需要,具备一定的借鉴和推广价值。

电路分析课程作为电气信息类专业的主要专业基础课程,对其教学内容、教学方法和教学手段的改革与探索一直是电路教学的重点。本文详细介绍了在电路教学改革中一些实践经验。对补充相关电工基础知识、拓宽相关课程内容、引入电气信息学科的最新发展、介绍相关的历史背景和解决实际电路应用问题等5个方面进行了有益的探索和实践。从而培养了学生分析、解决问题的能力,激发了学生的学习兴趣,改进和提高了该课程的教学质量。

This paper analyzes the structure and operation principle of three-level inverter and researches space vector PWM(SVPWM)control technique. The reliability of the system was estimated by simulation of the mathematical model.

<电路分析>课程作为电气信息类专业的主要专业基础课程,对其教学内容、教学方法和教学手段的改革与探索-直是电路教学的重点.详细介绍了在电路教学改革中的一些实践经验,即如何通过在教学过程中拓宽学生知识结构的方法和措施.通过补充相关电工基础知识、拓宽相关课程内容、引入电气信息学科的最新发展,介绍相关的历史背景和解决实际电路应用问题等5个方面进行了有益的探索和实践,从而能培养学生分析、解决问题的能力,激发学生的学习兴趣,改进和提高该课程的教学质量.