矢量双选取的永磁同步电动机直接转矩控制策略

A Double Vectors Selection Direct Torque Control Strategy of Permanent Magnet Synchronous Motor

在占空比直接转矩控制策略中,一个采样周期内作用一个有效电压矢量和一个零矢量,由于第2个电压矢量只能是零矢量,因此仍存在明显的转矩和磁链脉动。为了减小转矩和磁链脉动,该文提出一种矢量双选取的永磁同步电动机直接转矩控制策略,该策略在一个采样周期中作用两个电压矢量,第1个电压矢量根据开关电压矢量选择表来确定,第2个电压矢量根据转矩和磁链误差最小原理来选择,并依据转矩无差拍原理来分配两个电压矢量的作用时间,选择的第2个电压矢量不仅限于零矢量,而是扩大到任意电压矢量。实验结果表明：与占空比直接转矩控制策略相比,所提出的控制策略扩大了可选电压矢量范围,有效地减小了转矩和磁链脉动。

In the duty cycle direct torque control（DTC） strategy, an effective voltage vector and a zero vector were selected in a sampling period. There were still obvious torque and flux ripples because the second voltage vector was only a zero vector. In order to reduce torque and flux ripples, a vectors double selection direct torque control of permanent magnet synchronous motor（PMSM） strategy was proposed. In this strategy, there were two voltage vectors in each sampling period. The first voltage vector was selected according to the switching voltage vector selection table and the second voltage vector was selected by the minimum principle of torque and flux errors. The durations of two vectors was calculated through torque deadbeat control method. The second vector was no longer just zero vector, but extended to arbitrary voltage vector. Experimental results show that compared with the duty cycle DTC, the proposed strategy can expand the range of optional voltage vectors and effectively reduce torque and flux ripples.