摘  要：为了解决直接转矩控制中转矩脉动过大、开关频率不固定等问题，文中提出了一种新的基于占空比控制的异步电动机直接转矩控制方案。占空比控制技术通过在每个采样周期中插入零电压矢量来减小转矩的波动。本文提出了一种新的计算转矩上升和下降斜率的方法，求解出了占空比的计算公式。最后，对所提出的直接转矩控制算法进行了仿真。仿真结果表明，该方案可以大大减小输出转矩的波动。通过设定固定的采样周期，可以使逆变器的开关频率保持恒定,从而大大改善了调速系统的静、动态性能。
关键词：直接转矩控制；异步电动机；占空比控制

Abstract: In order to solve the problems of the torque ripple and variable switching frequency in traditional direct torque control (DTC) of the asynchronous machines, a new method based on duty ratio control was proposed in this paper. In duty ratio control technique，a zero voltage vector was applied in each sampling period to reduce the torque ripple. A new method of calculating the slopes of the rose and decline of the torque was proposed in this paper,  the duty ratio can be calculated. Finally, the proposed strategy was verified by simulations．Simulation results show that a great reduction of torque ripple was achieved. The switch frequency of the inverter can be made constant by setting the fixed sampling period. Therefore, a good statistic and dynamic performance are obtained.
Key words: direct torque control; asynchronous machines; duty ratio control