The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynch...The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynchronous parasitic torques have been discussed in great detail in the literature, but always separately, for a long time. However, systematization of the phenomenon still awaits. Therefore, it is worth summarizing the completeness of the phenomena in a single study – with a new approach at the same time-in order to reveal the relationships between them. The role of rotor slot number is emphasized much more than before. An existing, commonly used, but still impractical basic figure has been modified to more clearly demonstrate the response of the rotor for the harmonics of the stator. The need to treat differential leakage, asynchronous parasitic torques and attenuation together will be demonstrated: new formula for asynchronous parasitic torque is derived;the long-used characteristic curves for differential leakage and attenuation used separately so far was merged into one, correct curve in order to provide a correct design guide for the engineers.展开更多
A general method of calculating the saturable leakage reactances of squirrelcage asynchronous motors is presented.The method synthesized the variety of effectswhich affect the saturation of leakage magnetic circuit.An...A general method of calculating the saturable leakage reactances of squirrelcage asynchronous motors is presented.The method synthesized the variety of effectswhich affect the saturation of leakage magnetic circuit.And the saturable reactances canbe precisely evaluated in any running condition.The computation results of Y-series mo-tors are in good agreement with the test ones.展开更多
For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regula...For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regulator of high-voltage asynchronous motor. The mathematical model of the current-limiting transformer is deduced based on basic circuit theory. It can be found that a continuous variation reactance can describe the current-limiting transformer during starting process. The two variables functions of current and voltage are transformed into one-variable functions,and thus system control is greatly simplified. The voltage regulator is simulated on the basis. The simulation results show that this model has enough accuracy. Finally, the high-voltage asynchronous motor voltage regulator based on current-limiting transformer is designed and tested on this model.展开更多
The heating calculation of three-phase squirrel- cage asynchronous motor on the condition of starting for a prescribed rotary angle is firstly studied with time dissection method and its corresponding algorithm is pro...The heating calculation of three-phase squirrel- cage asynchronous motor on the condition of starting for a prescribed rotary angle is firstly studied with time dissection method and its corresponding algorithm is provided. Then based upon the algorithm, a new method for motor power selection is established. Motor initial power determined by load power ischecked and modified in terms of time crit erion, heating criterion,and starting torque criterion.An appropriate motor power which meets three criterions is obtained at last, in the meantime, working displacement matrix andfrequency matrix used for control are acquired. Lifting motor of MDJ1800 low-level high- speed palletizer is taken as a reaI case in the paper.展开更多
Deduced the relationship between the power factor (PF) and the angular fre-quency according to the simplified equivalent circuit of asynchronous motor, forming a power factor auto-control system. An anti-interference ...Deduced the relationship between the power factor (PF) and the angular fre-quency according to the simplified equivalent circuit of asynchronous motor, forming a power factor auto-control system. An anti-interference circuit was also introduced in the middle voltage link of inverter to avoid the shift of the optimum PF point caused by the change of the load and the reliable run of the control system was assured. The experi-ment results show that it has a good self-adaptation in the whole scope of speed ad-justment and an obvious economization on energy while it runs under load.展开更多
There are several problems existing in the direct starting of asynchronous motor such as large starting current,reactive power absorption from network side and weak interference-resistance,etc.Aiming at this,a compreh...There are several problems existing in the direct starting of asynchronous motor such as large starting current,reactive power absorption from network side and weak interference-resistance,etc.Aiming at this,a comprehensive energy-saving optimization model of asynchronous motor for voltage regulation based on static synchronous compensator(STATCOM)is put forward.By analyzing the working principle and operation performance of static synchronous compensator regulating voltage,a new energy-efficient optimization method for asynchronous motor is proposed based on the voltage regulator model to achieve soft start,continuous dynamic reactive power compensation and the terminal voltage stability control.The multi-objective optimal operation of asynchronous motor is realized by controlling the inverter to adjust the reactive current dynamically.The strategy reduces the influence of starting current and grid voltage by soft starting,and realizes the function of reactive power compensation and terminal voltage stabilization.The effectiveness and superiority of the proposed model is verified by the simulation analysis and the results of comparison with the motor started directly.展开更多
In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed i...In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed in three stages： thermal relay, electronic integrated protector, and microcomputer protector. In terms of sampling methods, the protection can be divided into two types： （1） the sampling current detection, which is implemented using a thermal relay with circuit breaker for the thermomagnetic tripping motor protection, and an electronic and solid state relay with circuit breaker and sof~ starter for the thermomagnetic tripping motor protection; （2） the sampling temperature detection, which is to directly detect electromotor winding temperature using bimetallic strip temperature relay, thermal protector, detecting coil, and heat resistance temperature relay. However, the second method is very expensive and difficult to maintain because a motor winding is necessary to directly bury, so it is used only in the cases requiring some frequent operations. Finally, the harmonious cooperation between overload protection device and motor or between overload protection device and short circuit protection device must be considered regardless of the protection device model.展开更多
In the process of the continuous development of power electronics technology, motor control gradually toward more optimized, efficient direction. In this paper, the variable frequency asynchronous motor control system...In the process of the continuous development of power electronics technology, motor control gradually toward more optimized, efficient direction. In this paper, the variable frequency asynchronous motor control system as the research object, mainly discusses the design requirements and design content of PLC in the variable frequency asynchronous motor control system, to achieve the control effect of the motor.展开更多
针对长短期记忆神经网络(Long Short Term Memory Neural Network,LSTMNN)在辨识异步电机故障时,因人工选择网络超参数导致的辨识精度下降问题,提出一种改进的蜣螂优化算法寻优LSTMNN的重要参数。首先,建立具有定子匝间短路故障的异步...针对长短期记忆神经网络(Long Short Term Memory Neural Network,LSTMNN)在辨识异步电机故障时,因人工选择网络超参数导致的辨识精度下降问题,提出一种改进的蜣螂优化算法寻优LSTMNN的重要参数。首先,建立具有定子匝间短路故障的异步电机系统模型;其次,利用精英反向学习策略、分段线性混沌映射、动态混沌权重因子和动态权重系数等方法改进蜣螂优化算法;最后,使用改进蜣螂优化算法对LSTMNN的关键超参数进行寻优。仿真结果表明,相较于基于蜣螂优化算法和基于改进麻雀算法的LSTMNN,提出的优化LSTMNN对故障及其他变量的辨识均方根误差分别降低了51.93%、36.49%,平均绝对误差分别降低了56.83%、43.99%,平均绝对百分误差分别降低了29.91%、22.25%,表明采用改进的蜣螂优化算法对LSTMNN的关键超参数寻优,可显著提高LSTM网络对电机故障及其他变量的辨识能力。展开更多
针对异步电机信号的故障敏感性差异大和故障特征提取困难等问题,提出了一种基于自混合注意力机制和时-空特征挖掘模型的异步电机故障诊断方法。该方法首先将自注意力机制擅长处理长距离依赖和全局信息特征的优势与squeeze-and-excitatio...针对异步电机信号的故障敏感性差异大和故障特征提取困难等问题,提出了一种基于自混合注意力机制和时-空特征挖掘模型的异步电机故障诊断方法。该方法首先将自注意力机制擅长处理长距离依赖和全局信息特征的优势与squeeze-and-excitation(SE)网络增强通道特征相关性的优点相结合,设计了一种新型的自混合注意力机制(self-hybrid attention mechanisms,SHAM),可以有效地降低异步电机电信号的故障敏感性差异;其次,将一维卷积神经网络(1D-convolutional neural network,1D-CNN)和SHAM相结合形成卷积自混合注意力模块(C-SHAM)来提取不同视野域的空间特征和捕获信号特征长范围依赖,同时抑制不同通道下同源信号内无关分量的影响;随后,将双向长短时记忆网络(bidirectional long and short term memory networks,Bi-LSTM)和SHAM相结合提出时序自混合注意力模块(BL-SHAM),进一步实现信号时序特征的再提取和不同通道特征的自适应融合;最后,通过分类器实现电机的故障识别。实验结果表明,在异步电机实验平台上,所提出的方法能够对异步电机的故障电信号进行有效地分类,平均准确率大于98%。展开更多
文摘The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynchronous parasitic torques have been discussed in great detail in the literature, but always separately, for a long time. However, systematization of the phenomenon still awaits. Therefore, it is worth summarizing the completeness of the phenomena in a single study – with a new approach at the same time-in order to reveal the relationships between them. The role of rotor slot number is emphasized much more than before. An existing, commonly used, but still impractical basic figure has been modified to more clearly demonstrate the response of the rotor for the harmonics of the stator. The need to treat differential leakage, asynchronous parasitic torques and attenuation together will be demonstrated: new formula for asynchronous parasitic torque is derived;the long-used characteristic curves for differential leakage and attenuation used separately so far was merged into one, correct curve in order to provide a correct design guide for the engineers.
文摘A general method of calculating the saturable leakage reactances of squirrelcage asynchronous motors is presented.The method synthesized the variety of effectswhich affect the saturation of leakage magnetic circuit.And the saturable reactances canbe precisely evaluated in any running condition.The computation results of Y-series mo-tors are in good agreement with the test ones.
基金Natural Science Foundation of Shanghai,China(No.14ZR1419100)Shanghai Science and Technology Commission,China(No.13160501500)+1 种基金Shanghai Maritime University Foundation,China(No.20130430)the Ministry of Transport Foundation of China(No.2013329 810350)
文摘For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regulator of high-voltage asynchronous motor. The mathematical model of the current-limiting transformer is deduced based on basic circuit theory. It can be found that a continuous variation reactance can describe the current-limiting transformer during starting process. The two variables functions of current and voltage are transformed into one-variable functions,and thus system control is greatly simplified. The voltage regulator is simulated on the basis. The simulation results show that this model has enough accuracy. Finally, the high-voltage asynchronous motor voltage regulator based on current-limiting transformer is designed and tested on this model.
基金This project is supported by National 863 Foundation (863-512-9801-06)
文摘The heating calculation of three-phase squirrel- cage asynchronous motor on the condition of starting for a prescribed rotary angle is firstly studied with time dissection method and its corresponding algorithm is provided. Then based upon the algorithm, a new method for motor power selection is established. Motor initial power determined by load power ischecked and modified in terms of time crit erion, heating criterion,and starting torque criterion.An appropriate motor power which meets three criterions is obtained at last, in the meantime, working displacement matrix andfrequency matrix used for control are acquired. Lifting motor of MDJ1800 low-level high- speed palletizer is taken as a reaI case in the paper.
基金Supported by Liaoning Educational Foundation(202183386)
文摘Deduced the relationship between the power factor (PF) and the angular fre-quency according to the simplified equivalent circuit of asynchronous motor, forming a power factor auto-control system. An anti-interference circuit was also introduced in the middle voltage link of inverter to avoid the shift of the optimum PF point caused by the change of the load and the reliable run of the control system was assured. The experi-ment results show that it has a good self-adaptation in the whole scope of speed ad-justment and an obvious economization on energy while it runs under load.
文摘There are several problems existing in the direct starting of asynchronous motor such as large starting current,reactive power absorption from network side and weak interference-resistance,etc.Aiming at this,a comprehensive energy-saving optimization model of asynchronous motor for voltage regulation based on static synchronous compensator(STATCOM)is put forward.By analyzing the working principle and operation performance of static synchronous compensator regulating voltage,a new energy-efficient optimization method for asynchronous motor is proposed based on the voltage regulator model to achieve soft start,continuous dynamic reactive power compensation and the terminal voltage stability control.The multi-objective optimal operation of asynchronous motor is realized by controlling the inverter to adjust the reactive current dynamically.The strategy reduces the influence of starting current and grid voltage by soft starting,and realizes the function of reactive power compensation and terminal voltage stabilization.The effectiveness and superiority of the proposed model is verified by the simulation analysis and the results of comparison with the motor started directly.
文摘In this paper, the relationship between the protection and control of asynchronous motor and all sorts of protection devices for asynchronous motor are briefly expounded. The protection of motor has mainly developed in three stages： thermal relay, electronic integrated protector, and microcomputer protector. In terms of sampling methods, the protection can be divided into two types： （1） the sampling current detection, which is implemented using a thermal relay with circuit breaker for the thermomagnetic tripping motor protection, and an electronic and solid state relay with circuit breaker and sof~ starter for the thermomagnetic tripping motor protection; （2） the sampling temperature detection, which is to directly detect electromotor winding temperature using bimetallic strip temperature relay, thermal protector, detecting coil, and heat resistance temperature relay. However, the second method is very expensive and difficult to maintain because a motor winding is necessary to directly bury, so it is used only in the cases requiring some frequent operations. Finally, the harmonious cooperation between overload protection device and motor or between overload protection device and short circuit protection device must be considered regardless of the protection device model.
文摘In the process of the continuous development of power electronics technology, motor control gradually toward more optimized, efficient direction. In this paper, the variable frequency asynchronous motor control system as the research object, mainly discusses the design requirements and design content of PLC in the variable frequency asynchronous motor control system, to achieve the control effect of the motor.
文摘针对长短期记忆神经网络(Long Short Term Memory Neural Network,LSTMNN)在辨识异步电机故障时,因人工选择网络超参数导致的辨识精度下降问题,提出一种改进的蜣螂优化算法寻优LSTMNN的重要参数。首先,建立具有定子匝间短路故障的异步电机系统模型;其次,利用精英反向学习策略、分段线性混沌映射、动态混沌权重因子和动态权重系数等方法改进蜣螂优化算法;最后,使用改进蜣螂优化算法对LSTMNN的关键超参数进行寻优。仿真结果表明,相较于基于蜣螂优化算法和基于改进麻雀算法的LSTMNN,提出的优化LSTMNN对故障及其他变量的辨识均方根误差分别降低了51.93%、36.49%,平均绝对误差分别降低了56.83%、43.99%,平均绝对百分误差分别降低了29.91%、22.25%,表明采用改进的蜣螂优化算法对LSTMNN的关键超参数寻优,可显著提高LSTM网络对电机故障及其他变量的辨识能力。
文摘针对异步电机信号的故障敏感性差异大和故障特征提取困难等问题,提出了一种基于自混合注意力机制和时-空特征挖掘模型的异步电机故障诊断方法。该方法首先将自注意力机制擅长处理长距离依赖和全局信息特征的优势与squeeze-and-excitation(SE)网络增强通道特征相关性的优点相结合,设计了一种新型的自混合注意力机制(self-hybrid attention mechanisms,SHAM),可以有效地降低异步电机电信号的故障敏感性差异;其次,将一维卷积神经网络(1D-convolutional neural network,1D-CNN)和SHAM相结合形成卷积自混合注意力模块(C-SHAM)来提取不同视野域的空间特征和捕获信号特征长范围依赖,同时抑制不同通道下同源信号内无关分量的影响;随后,将双向长短时记忆网络(bidirectional long and short term memory networks,Bi-LSTM)和SHAM相结合提出时序自混合注意力模块(BL-SHAM),进一步实现信号时序特征的再提取和不同通道特征的自适应融合;最后,通过分类器实现电机的故障识别。实验结果表明,在异步电机实验平台上,所提出的方法能够对异步电机的故障电信号进行有效地分类,平均准确率大于98%。
