异步电机新型占空比直接转矩控制方案

A Novel Direct Torque Control Strategy of Induction Machine Drives with Simple Duty Ratio Calculation

传统的基于矢量表的异步电机直接转矩控制(ST-DTC)存在较大的稳态误差以及转矩脉动等问题。目前已经提出了一些通过优化有效电压矢量占空比来减小转矩脉动的方法,然而,这些方法不仅计算复杂而且严重依赖电机参数。通过深入分析每个电压矢量引起的转矩和定子磁链变化率的基础上,提出一种简单且非常有效的占空比控制方法。该方法在占空比的计算中考虑了电机转速的影响,能同时减小输出转矩脉动及其稳态误差,并且尽可能保持了传统DTC结构简单和鲁棒性强的优点。仿真和实验结果验证了所提方法的有效性。

The traditional switching-based direct torque controlled（ST-DTC） induction motor drive is usually affected by large torque ripple and steady-state error of torque. The existing literature has proposed some methods to reduce torque ripple by optimizing the duty ratio of the active vector. However, these methods are usually complicated and depend heavily on motor parameters. Based on the analysis in instantaneous variation rates of stator flux and torque caused by each voltage vector, a simple and effective method considering the effect of machine velocity is proposed to acquire the duty ratio. The proposed scheme is able to reduce the torque ripple and steady-state error of torque significantly, while maintaining the simplicity and robustness of the traditional DTC at the most. Simulations and experimental results validate the proposed scheme.