基于转矩预测的异步电机直接转矩控制研究

针对传统的异步电动机直接转矩控制在低速时存在转矩脉动比较大的问题，提出了一种新的减小转矩脉动的直接转矩控制方法.在传统异步电机直接转矩控制的基础上推导出转矩微分方程，分析了转矩脉动的原因.引入转矩预测的思想，预测下一个控制周期所需要的转矩，根据其转矩分配下一个控制周期的电压空间矢量作用时间，来减小转矩脉动.实验结果表明,该方法可使转矩快速地收敛于给定值，具有传统直接转矩控制的优良动态性能，能够有效地减小转矩脉动，在200 r/min时转矩脉动减小为传统方法的50%，并没有改变定子磁链的控制性能,该控制方法易于用数字化的方法实现.

Research on direct torque control of induction machine based on torque prediction

To reduce the large torque ripple of induction machine subjected to conventional direct torque control (DTC) at low speeds, a new control strategy of DTC was proposed. On the basis of conventional DTC, a new torque differential equation was deduced and the reasons for torque ripple were analyzed. The control strategy introduced the idea of torque prediction to reduce the torque ripples. The torque of the next control period was predicted by the derived equation, and the operational time of the voltage space-vector in the next control period was determined based on the predicted torque. Experimental results show that the proposed strategy can rapidly converge on the set torque value and decrease the torque ripple effectively, and have the same dynamic performance as the conventional DTC. The torque ripples decrease a bout 50% and don't adversely affect the control performance of the stator flux at 200 r/min. The proposed strategy is easy to implement with difitalized methods.