基于矢量作用时间的新型预测转矩控制

Predictive Torque Control Based on Optimal Operating Time of Vector

为了获得期望的转矩和磁链幅值,文中推导了电压矢量作用下的两种最优矢量作用时间。借助矢量作用时间,提出一种无需权重系数整定的新型预测转矩控制(predictive torque control,PTC)算法。新型算法利用矢量作用时间衡量电压矢量对转矩和磁链的作用效果,代替了传统PTC中的转矩和磁链幅值预测环节,并将价值函数中的转矩和磁链幅值误差项分别替换为两种矢量作用时间,进而使价值函数仅包含时间这一量纲,从而避免了权重系数的整定问题。同时,依靠矢量作用时间选择最优矢量可以有效避免占空比调制环节在传统PTC算法中难以发挥作用的问题。新型算法将虚拟矢量与占空比结合,并对有限控制集进行优化,在减少了备选矢量的前提下获得更多的矢量方向和长度选择,提高了控制性能。实验结果表明该文算法具有更好的转矩和磁链控制性能。

In order to get the expected torque and flux modulus, this paper obtained two optimal operating time of vector separately through the analysis of the stator voltage and flux linkage equations. By means of the two optimal operating time, an improved predictive torque control（PTC） without weighting factor was proposed. The proposed method used the two optimal operating time to measure the influence on torque and flux modulus of one vector separately, and replaced the torque and flux modulus errors in the cost function with the two optimal operating time. Therefore, the proposed method gets rid of the weighting factor because the cost function only contains one dimension time. Meanwhile, the new cost function can avoid the situation that the duty cycle doesn＇t work in the traditional PTC. The proposed method combined duty cycle modulation with virtual vectors and optimized the finite control set. As a result, the new method not only has fewer alternative vectors, but also obtains better performance. Finally, experiments have been carried out to validate the proposed PTC strategy.