基于无速度传感器的直接转矩控制系统优化

针对传统异步电机直接转矩控制系统在低速运行状态下存在磁链轨迹发生波动、转矩脉动大的问题,提出一种新型异步电机直接转矩控制策略。采用滑模控制和空间矢量脉宽调制技术(SVPWM: Space Voltage Pwlse-Width Modulation), 引入滑模控制器, 以提高系统对参数变化和外界干扰的鲁棒性。利用空间电压矢量脉宽调制技术产生系统所需要的任意期望空间电压矢量, 使磁链轨迹更趋近于圆形, 即降低了转矩和磁链脉动,又增强了系统的鲁棒性。同时引入无速度传感器技术, 以提高系统工程应用性。通过在Matlab/ Simulink软件仿真结果表明, 新型直接转矩控制系统改善了磁链轨迹波动并有效地降低了转矩脉动, 使转速估计具有较高精度。

Improved DTC System of Induction Motor Based on Speed Sensorless

The traditional direct torque control of induction motor has a disadvantage. The ripple of flux and torque get increased when the system run at a low speed. After analyzing the reasons, a novel direct torque control of induction motor using sliding mode control and SVPWM(Space Voltage Pwlse-Width Modulation) is
presented. The sliding mode controller contributes to the robustness of system by reducing the influence of disturbances and uncertainties. The space voltage PWM(Pwlse-Width Modulation) modulation is used to produce the desired space voltage vector and decrease the ripple of flux. We use speed sensorless technology to improve in dustrial applicability of the system. In Matlab/ Simulink circumstance, the results of simulation prove that the novel direct torque control system reduces the ripple of flux and torque effectively and gets accurate speed.