该文以中国矿业大学徐海学院为例,探讨了电气工程及其自动化专业应用型人才培养模式.在应用型人才培养定位和地方新能源经济发展背景下,确定了以新能源发电和新能源电动汽车为电气专业特色.围绕新能源特色,分别构建了专业理论课程体系和实践教学体系,列举了集中实践教学环节的具体实训项目,并提出了应用型人才培养质量评价方法和保障措施.

开绕组负载双端级联是实现多电平的有效方法,其冗余特性可提高系统的可靠性.双三电平变换器级联可得到五电平变换器的输出特性,将五电平调制算法应用于双三电平变换器,计算量大、实现复杂.该文提出一种由单三电平虚拟矢量调制算法直接扩展到双三电平的解耦调制实现方法,不仅可完全消除共直流母线拓扑的零序电压,还可将系统的共模电压幅值抑制到直流侧电压的16.7％.修正单三电平中点电位控制的中点电流,通过单三电平调制算法实现双三电平变换器的中点电位主动控制,有效加快中点电位调节速度,所提双端级联多电平变换器调制策略可以保持和单三电平变换器调制相同的计算量.仿真和实验结果表明,该文所提由单三电平虚拟矢量调制算法直接扩展到双三电平变换器的解耦调制策略,可在全调制度、任意负载功率因数下,完全消除零序电压,有效抑制共模电压,并实现中点电位的主动控制.

针对参考矢量解耦的双端级联多电平变换器调制策略,提出一种直接在脉冲产生环节实现参考矢量解耦的方法,可有效简化算法、保证脉冲同步,并且可以和任意单端变换器的调制策略配合使用,具有通用性.结合双两电平级联三电平变换器、双三电平级联五电平变换器,分别给出180°,120.脉冲解耦调制策略的具体实现方法.通过最大线性调制度、直流电压利用率、零序电压消除效果等方面的对比分析,得到120.脉冲解耦调制策略更加适用于共直流母线双端级联多电平变换器的结论.仿真和实验结果验证了所提双端级联多电平变换器脉冲解耦调制策略的有效性.

双三相永磁同步电机(DTP-PMSM)参数受到负载量、温度等因素的影响而发生变化,降低了传统模型参考自适应系统(MRAS)无传感器控制方法的精度和稳定性.针对这个问题,提出一种基于电阻和磁链辨识分段处理的无传感器控制方法,电机低速运行时加入电阻辨识,高速运行时加入磁链辨识.为此,结合电机数学模型,研究了全速MRAS无传感器控制参数辨识系统,推导多参数辨识的自适应律,并验证参数估计唯一性和收敛性.仿真和实验结果表明,改进后的无传感器控制方法能够准确跟踪转子的速度和位置,具有良好的鲁棒性,降低了对参数的敏感性.

For the dual three-phase permanent magnet synchronous motor(dual-PMSM), the deadtime can introduce fifth and seventh current harmonics, and they are only constrained by the small stator leakage impedance, which means even if there are only small fifth and seventh voltage harmonics, the resulting fifth and seventh current harmonics will be very large. The harmonic current will make an increment of the system loss, thus lead to an reduce of the efficiency of the speed control system. This paper proposes a harmonic current suppression strategy for dual-PMSM based on least mean square (LMS) adaptive notch filter. This strategy suppresses the fifth and seventh harmonic currents by introducing four LMS adaptive notch filters in the subspace. The proposed algorithm has good dynamic performance and is insensitive to motor parameters that are offset within a certain range. The effectiveness of proposed method is verified by a set of comparative simulations and experiments.

传统PI控制器的双三相永磁同步电机四维电流矢量控制无法有效抑制交变的谐波电流分量,且动态响应速度较慢.为有效降低相电流谐波畸变率,提高矢量控制动态响应速度,提出了一种基于无差拍的双三相永磁同步电机电流预测控制策略.引入无差拍控制器控制基波平面电流,可以提高系统动态响应速度.同时,在谐波平面引入比例谐振(PR)控制器,可以实现对谐波平面电流的无静差跟踪.仿真和试验结果表明,所提出控制策略在动态响应和谐波抑制的效果上均优于基于比例积分(PI)控制器的四维电流矢量控制.

新能源技术的应用离不开高性能的数字信号处理器(DSP)的支持.随着新能源技术的发展,以新能源为背景的电气专业DSP课程建设与改革势在必行.针对目前电气专业DSP课程存在的问题,需要从专业理论和思政理论两方面进行建设和改革,对课程知识结构进行优化升级,并在教学中引入思政元素.通过课程内容和形式上的改革,为新能源相关课程提供硬件及编程技术支持,促进课程之间的交叉融合,培养能够适应新能源技术发展的电气专业应用型人才.

实践教学是应用型本科创新实践能力培养的有效保障,结合近年来本校电气专业学科竞赛参与情况,在实践课程具体实训项目的设置上,与学科竞赛有机结合.该文以两门集中实践教学课程为例,介绍了"赛教融合"下的项目设置与开展,"分层次、分阶段"精准参与学科竞赛,采用"全过程"考核方式,激发学生的学习热情.

无人机光伏巡检逐渐代替人工巡检,但其对光伏板上的树叶、鸟粪等小目标样本的检测仍存在缺陷,本文基于深度学习的SSD算法,研究了小目标识别问题.采取金字塔图像序列的数据增强,使SSD算法能够不增加噪声的情况下,最大可能的增加小目标样本的识别.通过未改进的SSD算法与改进之后的SSD算法进行检测对比,证实了改进之后的检测性能得到一定的提升.

针对传统六相感应电机发生绕组开路故障后转矩脉动大、谐波含量高、可靠性降低的问题,提出和改进了一种容错控制策略.推导了电机断路故障下的统一数学模型,建立了基于故障数学模型下的磁场定向控制,在谐波平面内加入了比例积分控制器,分别以一相、两相和三相定子绕组开路为例,进行了仿真和实验研究.结果 表明,该容错控制策略能有效减小绕组开路故障后的转矩脉动和电流谐波,能够实现绕组开路故障后的容错运行.

This paper deduces a unified mathematical model of open-circuit fault of six-phase induction machine, and purposes a fault-tolerence sensorless strategy based on the sliding mode observer(SMO) to estimate the rotor flux and rotor speed. In the proposed control scheme, the sliding mode observer is improved to achieve the rotor speed and rotor flux identification under healthy and arbitrary open circuit faults. The stability of the observer is proved by the Lyapunov function. The quasi proportional resonance (QPR) controller is introduced in the harmonic plane to suppress the harmonic current after the fault. The simulation and experiment results show that the proposed sensorless fault-tolerant control strategy based on sliding mode observer can accurately and effectively identify the rotor speed and rotor flux of the machine under normal and fault conditions.

In this paper, the stability of LC-type voltage source inverter is investigated, with the emphasis focused on the LC resonance. It has been found that the traditional capacitor-voltage inductor-current dual-loop control is unstable when the resonance frequency is higher than one-sixth of the sampling frequency. In addition, due to the coupling between current inner loop and voltage outer loop, it is difficult to design control parameters to ensure the system stability in traditional dual-loop control. In order to develop a systemic design principle, the capacitor-voltage control with inductor-current feedback active damping evolved from traditional dual-loop control is analyzed in detail. The mathematic model is established to reveal the reason of instability, and the stable regions are identified. Moreover, the optimal damping coefficient is also derived to enhance the system damping performance. Finally, the experimental results are provided to verify the effectiveness of the proposed method.

Due to the excessive zero-sequence voltage in dual three-level inverter fed open-end winding induction motor systems, zero sequence circumfluence which is harmful to switching devices and insulation is then formed when operating in a single DC voltage source supplying mode. Traditionally, it is the mean value instead of instantaneous value of the zero-sequence voltage that is eliminated, through adjusting the durations of the operating vectors. A new strategy is proposed for zero-sequence voltage elimination, which utilizes unified voltage modulation and a decoupled SVPWM strategy to achieve two same-sized equivalent vectors for an angle of 120 degrees, generated by two inverters independently. Both simulation and experimental results have verified its efficiency in the instantaneous value elimination of zero-sequence voltage.

In single-phase photovoltaic grid-connected inverter based on the conventional double closed-loop control strategy,the secondary voltage disturbances of DC bus will be generated,resulting in the triple harmonic of grid current,and affecting the quality of output energy.In view of these problems,based on analyzing the causes principle of the secondary voltage disturbances of DC bus,a double closed-loop control strategy increasing cycle integrator before DC bus voltage sampling is proposed in this paper.The strategy can remove the triple harmonic of grid current cased by the secondary voltage disturbances of DC bus,and then effectively suppress the effect on the quality of output energy.Simulation and experimental results are given to verify the rationality and effectiveness of the strategy.

主要研究三相异步电动机转子断条、气隙偏心这两种状态下的故障特征.采集了电动机的定子电流信号,通过对电流信号作FFT频谱分析,提取电流的故障特征,实现异步电动机系统的状态检测及电动机电气故障诊断.仿真实验结果发现单纯的傅里叶变换缺乏对信号局部特征的描述能力,不能有效地从定子电流的谐波中提取到故障特征.

为了实现煤炭指标的快速智能预测,建立了基于模糊聚类的径向基函数(RBF)神经网络预测模型,将已测定的收到基全水、收到基灰分、收到基挥发分和收到基全硫的含量作为分类指标进行模糊聚类,根据分类结果分别建立了基于径向基函数神经网络的定量分析模型,对干燥无灰基挥发分、空干基全硫、收到基低位发热量和空干基高位发热量进行了预测,并与直接使用径向基神经网络模型进行比较.结果表明,该分析模型不仅精度高,且泛化能力强,鲁棒性好.

A new coal desulfurization model of dielectric barrier discharge was built, and based on it, factors impacting on effect of desulfurization discharge, including dielectric types, dielectric thickness, gap spacing, supply voltage, power frequency were analyzed by simulation. The best fit solution of various factors was confirmed. Experimental data of coal desulfurization of dielectric barrier discharge was processed and analyzed, and it was found that the experimental results were consistent with the simulation results. Further inferences were made through comparative analysis of the discharge current spectrum and Lissajous waveform: discharge power can be improved through adding of coal; coal desulfurization effect of dielectric barrier discharge is reflected in low-order harmonics.

提出粗糙集(RS)和模糊支持向量机(FSVM)相结合的电动机故障诊断方法.先利用粗糙集对属性进行约简,然后将约简属性作为FSVM的输入,再对其进行训练,实现多分类,并使结果可视化.实际诊断结果验证了此方法的可行性与有效性.

微网系统中，逆变器可工作于离网模式和并网模式，并能实现两种运行模式的平滑切换。为了实现逆变器输出电压与电网电压保持同步、减小模式切换过程的功率冲击，预同步技术得到应用。但是，预同步技术的使用将会改变逆变器原有的下垂曲线，影响逆变器并网后的输出功率。对于上述问题，本文进行了详细的分析，并给出了解决方法。仿真验证了该方法的正确性和有效性。