针对传统直接转矩控制运行时存在逆变器开关频率不恒定、转矩脉动大的问题,从六相电机空间矢量解耦特点入手,提出了一种转子磁链闭环的六相感应电机反推式空间矢量调制与直接转矩控制(space vector modulation and direct torque contro...针对传统直接转矩控制运行时存在逆变器开关频率不恒定、转矩脉动大的问题,从六相电机空间矢量解耦特点入手,提出了一种转子磁链闭环的六相感应电机反推式空间矢量调制与直接转矩控制(space vector modulation and direct torque control,SVM-DTC)方法.首先,分析和建立了六相电机数学模型,并运用新虚拟电压平衡矢量来确定空间电压矢量脉宽调制(space voltage vector pulse width modulation,SVPWM)方案以便减小电机定子谐波电流;其次,应用反推算法设计转速反推控制器替代传统直接转矩控制中的转速PI控制器,应用转矩反推控制器与磁链反推控制器得到静止坐标系下的定子电压实际分量;最后,在Matlab/Simulink中进行系统的仿真验证.通过仿真与PI控制的改进DTC方法相对比可知,该控制方案下电机具有响应速度快、转矩脉动小、可调参数少和可改善定子电流波形等优点,并使逆变器工作在恒定开关频率下.展开更多
针对基于电流型变流器的直驱风电系统中的永磁同步发电机(permanent magnetic synchronous generator,PMSG)控制系统,提出一种基于定子磁链定向的空间矢量调制直接转矩控制(space vector modulation direct torque control,SVM-DTC)算法...针对基于电流型变流器的直驱风电系统中的永磁同步发电机(permanent magnetic synchronous generator,PMSG)控制系统,提出一种基于定子磁链定向的空间矢量调制直接转矩控制(space vector modulation direct torque control,SVM-DTC)算法,根据该算法,通过合成的电流空间矢量可完全补偿电机的转矩和磁链与参考值之间的误差,同时能保证功率器件开关频率的恒定。其中定子磁链估计采用自适应补偿的改进积分算法,解决了纯积分存在直流偏移和低通滤波存在幅值与相位误差的缺陷,从而达到高性能的DTC效果。仿真与实验结果表明,基于定子磁链定向的SVM-DTC算法能有效提高系统的动静态性能且易于实现机侧的单位功率因数控制。展开更多
AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for...AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.展开更多
文摘针对传统直接转矩控制运行时存在逆变器开关频率不恒定、转矩脉动大的问题,从六相电机空间矢量解耦特点入手,提出了一种转子磁链闭环的六相感应电机反推式空间矢量调制与直接转矩控制(space vector modulation and direct torque control,SVM-DTC)方法.首先,分析和建立了六相电机数学模型,并运用新虚拟电压平衡矢量来确定空间电压矢量脉宽调制(space voltage vector pulse width modulation,SVPWM)方案以便减小电机定子谐波电流;其次,应用反推算法设计转速反推控制器替代传统直接转矩控制中的转速PI控制器,应用转矩反推控制器与磁链反推控制器得到静止坐标系下的定子电压实际分量;最后,在Matlab/Simulink中进行系统的仿真验证.通过仿真与PI控制的改进DTC方法相对比可知,该控制方案下电机具有响应速度快、转矩脉动小、可调参数少和可改善定子电流波形等优点,并使逆变器工作在恒定开关频率下.
文摘针对基于电流型变流器的直驱风电系统中的永磁同步发电机(permanent magnetic synchronous generator,PMSG)控制系统,提出一种基于定子磁链定向的空间矢量调制直接转矩控制(space vector modulation direct torque control,SVM-DTC)算法,根据该算法,通过合成的电流空间矢量可完全补偿电机的转矩和磁链与参考值之间的误差,同时能保证功率器件开关频率的恒定。其中定子磁链估计采用自适应补偿的改进积分算法,解决了纯积分存在直流偏移和低通滤波存在幅值与相位误差的缺陷,从而达到高性能的DTC效果。仿真与实验结果表明,基于定子磁链定向的SVM-DTC算法能有效提高系统的动静态性能且易于实现机侧的单位功率因数控制。
基金Project(SS2012AA04104)supported by High-tech Research and Development Program of China
文摘AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.
