The nonlinear characteristics of an inverter can lead to inconsistencies between the command voltage and the inverter output voltage, which is referred to as the output distortion voltage of the inverter. This distortion voltage contains fundamental and harmonic components, and the distortion voltage of each phase varies with changes of the output current of the inverter. The distortion voltage affects the output current of the inverter and affects the stability of the control system, especially for motors with small inductances. In this paper, the distortion voltage generated by the inverter is compensated by injecting an arctangent-based compensation voltage to the command voltage. Through an analysis of the harmonic voltage generated by the arctangent function, the unique arctangent compensation voltage can be automatically obtained through closed-loop integral control and the relationship between each harmonic voltage. Compared with traditional methods, the method proposed in this paper does not require a tuning process to determine the relationship between the inverter and the output current. On a PMSM experimental platform with a small inductance, the comparison experiment with the traditional method verifies that the compensation strategy proposed in this paper can achieve a good compensation effect under a wide range of currents. In particular, under low current conditions, the SHD of the phase current is decreased from 43.03

The single dc-link current sensor control of permanent magnet synchronous motor (PMSM) based on model predictive control (MPC) combines the advantages of high dynamic response of model prediction and low complexity of single current sensor. However, under traditional MPC strategy, the current reconstruction and tracking performance of single current control is inadequate, which can not meet the requirements of high performance control. In order to solve the above problems, a discrete space vector modulation-model predictive control (DSVM-MPC) method is designed. By dividing the control period into four equal parts, the number of alternative vectors is expanded, then the accuracy of current tracking has been improved. On this basis, by flexibly adjusting the action sequence of different vectors in the control period, the sampling moment and sampling interval of single current sensor are fixed, then the reconstruction error is reduced. In order to solve the problem of parameter mismatch under the MPC, an extended state observer (ESO) is introduced to observe the parameter disturbance and predictive current, which improves the parameter robustness and the accuracy of reconstructed current. Experimental results verify the effectiveness of the proposed method.

In order to improve the output performance of the multilevel converter, this paper proposes a new cascade converter with neutral point opened. The converter consists of a cascaded H-bridge and a half-bridge circuit connected in series. The output level can be almost doubled by adding a simple half-bridge circuit. At the same time, the half-bridge circuit does not need a voltage source, only uses a capacitor to supply power, and can achieve charge-discharge balance without any closed-loop control, thereby achieving self-balance of capacitor voltage. First, this article introduces the topology and working principle of the new converter. Secondly, in order to achieve the normal operation of the converter, a simplified algorithm as its modulation strategy is introduced. Finally, simulation and experimental analysis are carried out under grid-connected conditions. The results show that the converter can obtain high-quality output waveforms at low switching frequency, which verifies the effectiveness and superiority of the converter.

In this paper, a partial discharge（PD） pattern recognition experiment was designed, a sample-layered experiment analysis method based on intelligent algorithm was improved, and a new experiment-teaching mode based on teaching and research integration was established. Three kinds of discharge defects were designed to acquire partial discharge signals, partial discharge data was cleaned by wavelet transform, partial discharge phase distribution（PRPD） maps were constructed based on statistics and their statistics features were extracted,efficiency of discharge pattern recognition by using traditional BP neural network（BPNN） algorithm and improved sample-layered algorithm was compared and analyzed. The experiment results show that sample-layered intelligent algorithm can improve efficiency of discharge pattern recognition. Based on teacher’s scientific research achievements, this experiment comprehensively utilizes interdisciplinary ways of electricity, information, statistics,computer and so on, and establishes a new experiment teaching and research integration mode of “based on practice, progressive inspiration, interdisciplinary crossing”, which trains students’ practice ability and comprehensive application ability of knowledge, and cultivates students’ exploration enthusiasm and innovation consciousness.

The course design based on the electric drive system of mine hoist involves many courses knowledge,which is helpful to exercise students’ ability to comprehensively use professional knowledge and solve complex engineering problems. However, the design results are difficult to be verified by physical experiments in teaching activities. Aiming at the problems of site restriction and safety in the teaching process, the virtual simulation experiment platform of mine hoist transmission system is designed in this paper. The virtual experiment platform has the functions of equipment parameters and control parameters setting, improving system simulation operation and running result output, and can run independently from the MATLAB environment. The virtual simulation experiment can not only assess the students’ mastery of relevant knowledge and comprehensive application ability,but also help students to understand the coal mine production site and technological process, which is of great significance to the training of excellent engineers.

作为培养动手实践能力的重要课程,传统DSP课程教学模式下学生实验课时不足、实践周期较长,导致学习效果下降.为解决这一问题,设计一款以TMS320F28335 为核心的DSP"口袋实验室",并包含仿真器功能模块可有效拓展学生实验场所."口袋实验室"提供的扩展模块实现低压两电平逆变器,实现单电阻采样重构三相电流实验的硬件支撑.通过"口袋实验室",学生可将课堂学习的理论知识与实践结合,缩短从理论学习到实践的时间间隔,提升教学效果.

为解决在实际运行中开关磁阻电动机(SRM)存在轴承老化、定转子结构变形、温度变化、电磁噪声和电动机振动等随机因素引起的SRM模型参数与实际电动机参数不匹配的问题,提出一种SRM参数在线辨识方法.该方法将电感模型中因转子位置和磁饱和引起的电感变化定义为快速变化参数;对上述随机因素引起的电阻和电感变化定义为慢速变化参数,建模时引入递归最小二乘法(RLS)对上述参数进行辨识校正.搭建参数辨识的仿真模型和实验平台,并对位置估计进行了探究.仿真和实验结果表明,该参数在线辨识方法具有有效性,并且适用于SRM位置估计.

一流专业和一流课程的建设核心是打造融入思政元素的"金课",以"电机与拖动基础"专业核心课程为例,对课程教学现状进行了分析,结合专业和课程的教学目标,在教学内容中融入了思政元素,并给出了成绩评定方法.以三相异步电动机的调速课程内容为教学案例,设计了思政教学内容,启发了学生的学习兴趣,结合课程思政教育激发学生的民族自豪感,树立社会主义核心价值观,培养学生的家国情怀.

Inorder to better meet the needs of power development, a non-contact voltage and current integrated measurement sensor is designed. One of its structural innovations is based on PCB, which reduces the insulation requirements for sensors. Secondly, the voltage and current measurement are integrated to increase the sensor measurement function. The sensor uses capacitive coupling principle and electromagnetic induction principle to measure the voltage and current of the line to be measured. The simulation model of the sensor structure is built by Maxwell, its structure is optimized, and the subsequent signal processing circuit is designed to realize the non-contact voltage and current waveform acquisition, monitoring and analysis.

传统的级联H桥静止无功补偿器相间电压均衡控制策略分析计算较为复杂,且需要调节PI参数,为此提出了一种无需参数调节的相间电压均衡控制策略.只需排序比较大小,通过查表法即可求出待注入的零序分量,简化了相间电压平衡算法;针对相内电压均衡控制策略,基于伏秒平衡控制原理提出了一种H桥模块作用时间直接修正法,与基于时间计算的载波水平移相调制策略相配合,即使在电压不平衡的暂态过程中也能够完全实现与上层控制的解耦,并且这种方法能够容易地扩展到级联度更高的SVG系统中.最后,通过在Simulink仿真平台与实验室条件下搭建的小功率实验平台验证了算法的有效性与可行性.

逆变器带有不平衡负载时,输出电压中存在负序分量,在正序旋转坐标系下负序分量表现为二倍频交流分量,PI调节器无法完全抑制该负序分量.为此,提出采用重复控制器.基于重复控制器的基本原理以及结构,从稳定性、抗干扰性能、误差收敛速度、稳态误差4 个方面对重复控制器的性能进行分析;给出重复控制器参数详细设计过程,并对所设计的重复控制器进行了稳定性校验.通过在Simulink仿真平台与实验室条件下搭建的小功率实验平台验证了算法的有效性与可行性.

As a special disc motor, a printed permanent magnet synchronous motor (PMSM) uses a PCB printed board as the stator, which has the advantages of simple assembly, short axial distance, no stator slot, low eddy current loss, etc. Due to the stator-less core structure and the small number of winding turns, the inductance of the motor is very small. When vector control technology is used to drive the motor, the motor current pulse vibration is intense, there is a large number of integer multiples of the switching frequency high-frequency harmonics, there is also torque output pulse vibration, and it cannot be sampled to obtain the actual working state of the motor stator current, which affects the sliding mode sensorless control algorithm in terms of stator current estimation. Then it affects the motor speed and position estimation. In this paper, a solution involving high switching frequency control is proposed to obtain the characteristics of this kind of motor. In addition, the sensorless control of the motor based on the super-twisting sliding mode is realized. Simulation and experiments show the stability and effectiveness of the motor position free control system, and solve the problems related to severe motor stator current oscillation, motor output electromagnetic torque oscillation, and poor control performance of the sensorless algorithm caused by a small motor stator inductance.

Adopting the connection group structure of Dd0yn11, this paper designs a novel low-voltage (LV) distribution transformer (DT) based on inductive filtering (IF), and verifies the proposed transformer through a comprehensive innovation experiment.Firstly, the functional relationship between valve-side harmonic current and grid-side current was derived according to the winding model, and the filtering features were obtained to compute the impedance between the valve-and grid-side windings.Next, the design calculation was carried out by the engineering magnetic circuit (EMC) method.After that, a three-dimensional (3D) model was established for the proposed transformer on ANSYS Maxwell.The simulation results show that the proposed transformer meets the design requirements on the relevant parameters, and eliminates the harmonic pollution in the grid.Finally, the proposed transformer was proved correct and effective through experiments, and found to stimulate studentsꞌ interest in learning and innovation.

传统的电气工程及其自动化专业人才培养模式不能充分体现能源互联网、信息技术、大数据、人工智能等领域的学科交叉性,不能适应未来"碳达峰、碳中和"形势下工业发展对新型人才的需求.电气工程及其自动化专业人才培养方案的制定既受到专业认证、新工科建设等外部的影响,也要遵循原有的传统优势.中国矿业大学电气工程及其自动化专业明确了"双碳"形势下的人才培养目标,建构了相应的课程知识体系,并有机地融入了课程思政元素.

针对目前同步磁阻电动机转矩脉动大、转矩密度与功率因数低等缺点,分析了同步磁阻电动机转子磁障占有率对电动机性能的影响,提出一种新的不均匀转子结构.使用Ansys软件搭建的有限元仿真模型进行仿真分析,在结构设计中结合C型磁障达到更好的转矩输出性能与效率表现,对转子磁桥的布置进行了机械应力的验证.仿真结果表明,同步磁阻电动机转子设计能有效降低转矩脉动,提高输出效率.

鉴于目前双向全桥LLC谐振变换器反向运行电压增益小于1,设计了一种新型控制策略,使其反向运行时电压增益不仅大于1,而且比原始控制策略下的电压增益更大,且效率更高.该设计在变频控制的基础上加入了移相控制策略,优化了原始控制策略,使用Matlab/Simulink搭建了变换器反向运行的仿真模型.经实验验证,新型控制策略可以进一步提高反向电压增益,证明了所提出策略的可行性.

Transshipment of compacted soybean is characterized by labor-intensive processes, long operating times, and a great amount of dust that cannot be collected by sealed devices. This dust significantly reduces air quality of the workshop and represents a great threat to human health. Solving this problem has been a great challenge in the soybean storage industry. For this reason, in the present study the concept of a transshipment system for soybean clearance was proposed. This system can simultaneously achieve real-time transshipment of falling materials and air curtain control of fugitive dust. The main factors influencing the performance of the air curtain dust control system were investigated using numerical simulation, and the effects of the exhaust-to-pressure ratio K and air curtain outlet velocity Von dust control efficiency were determined. Results showed that the width of the dust-collecting paths increased with increasing K and V values. We also found out that dust-escape paths were mainly concentrated in the transition height between the complete air curtains and local air curtains. At the beginning of the process, dust control efficiency rapidly increased and the increment rate became slower as K increased. When K = 1.5 and V = 5-6 m/s, dust control efficiency reached values up to 95.54-96.27%. Based on numerical simulation results, the prototype transshipment system for soybean clearance was developed, and the effectiveness of air curtain dust control was validated via smoke tracing experiments. After the application of the developed system, occupational lung disease can be significantly reduced, and transshipment efficiency per clearance can be enhanced by approximately 67% (about 50,113 yen can be saved in terms of energy consumption and labor resources). An extra granary can be saved after using the newly developed system for 36.5-52.1 clearances. (c) 2021 Elsevier B.V. All rights reserved.

Since the matrix converter (MC) has no intermediate DC energy storage link, any disturbance at the input will affect the output. To guarantee the safe and stable operation of MC system, a feed-forward compensation (FFC) strategy for MC operation in abnormal input voltage conditions, including voltage unbalanced, non-sinusoidal and instantaneous drop, is presented in this paper. The drive performance on the Space Vector Modulation (SVM) Strategy of MC under abnormal input voltage conditions is deeply analyzed. It is proved that the unbalance, non-sinusoidal and instantaneous drop of the input voltage can be compensated by real-time adjusting the SVM coefficient of the control system. The output voltage of MC is kept at normal value by compensating the change of virtual DC voltage. Finally, the control strategy is verified by simulation and experiment.

Air curtains have rectangular lateral shape in most of the current studies. Since they often fail to meet the dust control requirements of the special-shaped dust control area formed by space constraints and other factors, this problem can be solved by alternative development of trapezoidal air curtains (TAC). The core technology of such air curtain aimed at a special-shaped dust control area was proposed. Using numerical simulation via Fluent, the structural optimizations of air curtain unit were realized. The air supply effects of divergent and contracted TAC were compared, with the new calculation model of air volumes, which results were applied to the special-shaped dust control area. Numerical simulations verified by field application proved that under higher dust concentration conditions, the mixed air curtain case with added TAC outperformed the fully rectangular case by higher dust control efficiency (97.75% versus 96.16%), saving about 40.4% air volume.

混合励磁开关磁通永磁电动机兼具传统永磁电动机和开关磁通电动机的优点,可靠性高,具有较高的研究价值.为实现励磁磁场的有效调节与控制,提出一种新型混合励磁开关磁通电动机,并对不同结构方案的调磁能力和电磁特性进行了有限元分析,得到了更加优化的电动机结构形式,为该类电动机的设计与应用提供了技术参考.