Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training a...Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training algorithms. The application of neural networks to control interior permanent magnet synchronous motor using direct torque control （DTC） is discussed. A neural network is used to emulate the state selector of the DTC. The neural networks used are the back-propagation and radial basis function. To reduce the training patterns and increase the execution speed of the training process, the inputs of switching table are converted to digital signals, i.e., one bit represent the flux error, one bit the torque error, and three bits the region of stator flux. Computer simulations of the motor and neural-network system using the two approaches are presented and compared. Discussions about the back-propagation and radial basis function as the most promising training techniques are presented, giving its advantages and disadvantages. The system using back-propagation and radial basis function networks controller has quick parallel speed and high torque response.展开更多
The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was install...The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.展开更多
A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two pha...A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.展开更多
为了抑制轴向磁场磁通切换永磁(axial field flux-switching permanent magnet,AFFSPM)电动机齿槽转矩引起的转矩脉动,提出一种基于自适应扩展卡尔曼滤波器的齿槽转矩抑制方法.该方法根据齿槽转矩分析结果,以及AFFSPM电动机数学模型和...为了抑制轴向磁场磁通切换永磁(axial field flux-switching permanent magnet,AFFSPM)电动机齿槽转矩引起的转矩脉动,提出一种基于自适应扩展卡尔曼滤波器的齿槽转矩抑制方法.该方法根据齿槽转矩分析结果,以及AFFSPM电动机数学模型和损耗模型,将齿槽转矩引起的系统转矩脉动作为扩展状态变量,与电流环的反馈电流一起构造系统扩张状态空间方程.在状态估计过程中引入了遗忘因子,提高观测精度和速度.与基于谐波电流注入法抑制齿槽转矩的控制方法进行了控制性能和突变工况对比.结果表明:所提出控制方法在低速时转矩脉动降低了43.5%,电损耗降低了14.8%,能更有效抑制齿槽转矩脉动和提高系统效率.展开更多
单相开路故障的五相永磁同步电机(permanent-magnet synchronous motor,PMSM)采用有限集模型预测转矩和磁链控制(finite-control-set model predictive torque and flux control,FCS-MPTFC)策略,存在转矩脉动大、价值函数的权重系数整...单相开路故障的五相永磁同步电机(permanent-magnet synchronous motor,PMSM)采用有限集模型预测转矩和磁链控制(finite-control-set model predictive torque and flux control,FCS-MPTFC)策略,存在转矩脉动大、价值函数的权重系数整定困难、迭代计算量大以及共模电压(commonmode voltage,CMV)高等问题。为此,该文提出一种简化FCS-MPTFC策略。首先,建立五相PMSM在单相开路故障情况下的数学模型,并分析CMV产生的机理。其次,以抑制3次谐波电流的原则合成等幅值虚拟电压矢量(virtual voltage vector,V^(3)),并将转矩和磁链价值函数等效转化为电压价值函数,同时采用无差拍控制思想计算出参考电压矢量,进而通过合理划分扇区,直接获得最优V^(3)。最后,选择方向相反的两个基电压矢量代替零矢量,以减小开路故障下的CMV。仿真和实验结果表明:所提控制策略不仅能抑制单相开路故障导致的转矩脉动、降低计算负荷和CMV、抑制电流谐波,而且具有优良的稳态和动态性能。展开更多
交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种...交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种注入多谐波电流产生的转矩补偿原有转矩脉动的控制策略。推导适用于任意次谐波磁链产生的转矩脉动通用解析模型;并基于此模型,给出利用谐波电流抑制转矩脉动的理论依据;提出在同步旋转坐标系下注入多次谐波电流的方法,抑制由2、4、5、7、11、13次谐波反电势引起的3、6、12次转矩脉动;并利用准-比例谐振控制器实现谐波电流的精确跟踪。最后,以一台三相9槽10极交替极永磁电机为例,通过不同工况下的转矩脉动抑制实验,验证所提控制策略的有效性。展开更多
基金the National Natural Science Foundation of China (60374032).
文摘Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training algorithms. The application of neural networks to control interior permanent magnet synchronous motor using direct torque control （DTC） is discussed. A neural network is used to emulate the state selector of the DTC. The neural networks used are the back-propagation and radial basis function. To reduce the training patterns and increase the execution speed of the training process, the inputs of switching table are converted to digital signals, i.e., one bit represent the flux error, one bit the torque error, and three bits the region of stator flux. Computer simulations of the motor and neural-network system using the two approaches are presented and compared. Discussions about the back-propagation and radial basis function as the most promising training techniques are presented, giving its advantages and disadvantages. The system using back-propagation and radial basis function networks controller has quick parallel speed and high torque response.
基金Research financially supported by Human Resource Training Project for Regional Innovation of Ministry of Education,Science and Technology(MEST)National Research Foundation(NRF)the Second Stage of Brain Korea 21 Projects,Korea
文摘The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.
基金supported by the National Natural Science Foundation of China(61463025).
文摘A global fast terminal sliding mode(GFTSM)-based model predictive torque control(MPTC)strategy is developed for permanent magnet synchronous motor(PMSM)drive system with only one phase current sensor.Generally two phase-current sensors are indispensable for MPTC.In response to only one phase current sensor available and the change of stator resistance,a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC.Moreover,in view of the variation of system parameters and external disturbance,a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness.In this paper,the GFTSM,based on sliding mode theory,employs the fast terminal sliding mode in both the reaching stage and the sliding stage.The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors.On the other hand,compared with proportional-integral(PI)-based and sliding mode(SM)-based MPTC PMSM drive systems,it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion(THD)index of three-phase stator currents in the presence of variation of load torque.The simulation results validate the feasibility and effectiveness of the proposed scheme.
文摘为了抑制轴向磁场磁通切换永磁(axial field flux-switching permanent magnet,AFFSPM)电动机齿槽转矩引起的转矩脉动,提出一种基于自适应扩展卡尔曼滤波器的齿槽转矩抑制方法.该方法根据齿槽转矩分析结果,以及AFFSPM电动机数学模型和损耗模型,将齿槽转矩引起的系统转矩脉动作为扩展状态变量,与电流环的反馈电流一起构造系统扩张状态空间方程.在状态估计过程中引入了遗忘因子,提高观测精度和速度.与基于谐波电流注入法抑制齿槽转矩的控制方法进行了控制性能和突变工况对比.结果表明:所提出控制方法在低速时转矩脉动降低了43.5%,电损耗降低了14.8%,能更有效抑制齿槽转矩脉动和提高系统效率.
文摘单相开路故障的五相永磁同步电机(permanent-magnet synchronous motor,PMSM)采用有限集模型预测转矩和磁链控制(finite-control-set model predictive torque and flux control,FCS-MPTFC)策略,存在转矩脉动大、价值函数的权重系数整定困难、迭代计算量大以及共模电压(commonmode voltage,CMV)高等问题。为此,该文提出一种简化FCS-MPTFC策略。首先,建立五相PMSM在单相开路故障情况下的数学模型,并分析CMV产生的机理。其次,以抑制3次谐波电流的原则合成等幅值虚拟电压矢量(virtual voltage vector,V^(3)),并将转矩和磁链价值函数等效转化为电压价值函数,同时采用无差拍控制思想计算出参考电压矢量,进而通过合理划分扇区,直接获得最优V^(3)。最后,选择方向相反的两个基电压矢量代替零矢量,以减小开路故障下的CMV。仿真和实验结果表明:所提控制策略不仅能抑制单相开路故障导致的转矩脉动、降低计算负荷和CMV、抑制电流谐波,而且具有优良的稳态和动态性能。
文摘交替极永磁(consequent pole permanent magnet,CPPM)电机每对极下的气隙磁密不对称,在特定极槽配合下其反电动势(electromotive force,EMF)中存在2、4次等偶次谐波分量,引起额外的转矩脉动,降低转矩输出品质。为解决上述问题,提出一种注入多谐波电流产生的转矩补偿原有转矩脉动的控制策略。推导适用于任意次谐波磁链产生的转矩脉动通用解析模型;并基于此模型,给出利用谐波电流抑制转矩脉动的理论依据;提出在同步旋转坐标系下注入多次谐波电流的方法,抑制由2、4、5、7、11、13次谐波反电势引起的3、6、12次转矩脉动;并利用准-比例谐振控制器实现谐波电流的精确跟踪。最后,以一台三相9槽10极交替极永磁电机为例,通过不同工况下的转矩脉动抑制实验,验证所提控制策略的有效性。
