异步电机直接转矩控制模糊DSVM控制策略

针对传统异步电机直接转矩控制系统低速转矩脉动大、电流畸变严重、磁链轨迹内陷以及开关频率不固定等问题,基于离散空间电压矢量调制(DSVM)技术和模糊控制技术,提出了一种改善低速性能的控制策略.利用DSVM技术合成19种电压矢量,使低速区可供选择的电压矢量数目增加,提高了转矩调节器的控制精确度,采用模糊控制器选择电压工作矢量,明显抑制了转矩脉动.仿真结果表明,改进的DSVM控制策略及模糊控制算法的应用,在保证开关频率恒定的前提下,明显克服了低速磁链轨迹内陷、转矩脉动大、电流畸变严重等缺点,有效地改善了直接转矩控制的低速运行性能.

Fuzzy DSVM strategy in the direct torque control of an induction motor

Some problems such as large torque ripples,current distortion,flux depression and unstable switching frequency exist in the conventional direct torque control of induction motor in low speed range.Based on the technology of discrete space vector modulation(DSVM) and fuzzy control,this paper proposes a control strategy to improve the performance of low-speed,DSVM synthesis technology is used to produce 19 types of vector voltage,which makes the number of low-speed zones vector voltage increase and gains accuracy of torque control regulator,and the fuzzy logic controller is used to select the voltage vector to inhibit torque ripple.Simulation results prove that the large torque ripple,current distortion,flux depression have been overcome remarkably under the condition of maintaining the switching frequency constant by the application of the improved DSVM-DTC and the fuzzy DSVM-DTC strategy.The low speed performance of direct torque control has been improved effectively.