模糊自适应控制在永磁同步电机直接转矩控制的应用

Application of Adaptive Fuzzy Controller to Interior Permanent Magnet Synchronous Motor Direct Torque Control

提出了一种新的永磁同步电机直接转矩控制方法。永磁同步电机直接转矩控制中,没有任何一个逆变器开关矢量能够产生恰好的定子电压,使该电压可以产生所期望的转矩和磁通变化,因而产生了较大的转矩和磁通脉动,并且逆变器的开关周期不恒定。这种脉动通过控制正反电压矢量作用时间可以降低,提出了一种自适应模糊控制器确定占空比的方法。该控制器输出部分的比例因子可以根据转矩的变化趋势经自适应机构的模糊规则库在线调整,不仅可以使永磁同步电机直接转矩控制系统保持恒定的开关频率,而且可以有效地减小磁链和转矩脉动,特别是低速时的转矩脉动。仿真验证了自适应模糊永磁同步电机直接转矩控制策略的有效性。

A novel direct torque control （DTC） scheme for an interior permanent magnet synchronous motor（IPMSM） is proposed in this paper, which features almost fixed switching frequency and low torque and flux ripple. In interior permanent magnet synchronous motor direct torque control, none of the switching states is able to generate the exact voltage vector to produce the desired changes in torque and flux in most of the switching instances. This causes a high ripple in torque. This ripple can be reduced by applying a selected inverter switching state for a portion of switching period （defined as duty） and the reverse switching state for the rest of the period. Adaptive fuzzy logic idea is introduced into the system. The controller output scaling factor is adjusted on line by fuzzy rules according to the current torque variety trend of the controlled process. The torque ripple has been significantly reduced compared with those of the basic interior permanent magnet synchronous motor direct torque control reported in the literature, particularly at low speeds. Simulation illustrates the operation and performance of proposed adaptive fuzzy-logic-based controller.