基于预期电压矢量的永磁同步电机直接转矩控制系统

摘要

传统的基于开关表的直接转矩控制存在着转矩和磁链脉动大、开关频率不同定等缺点.考虑到空间矢量脉宽调制技术在一个控制周期内能够产生等效的任意相位的电压矢量,为了改善直接转矩控制的控制效果,提出了一种预期电压矢量的确定方法,并用PI控制器代替传统直接转矩控制系统的滞环比较器,构造出一种基于预期电压矢量的直接转矩控制策略.通过与传统直接转矩控制策略的对比试验,表明提出的直接转矩控制策略具有电流谐波小、转矩和磁链的脉动小、速度响应快、稳态误差小等特点.%Conventional switch table based direct torque control ( DTC) has some faults of large torque and flux ripple, inconstant inverter switch frequency. Consider that space vector pulse width modulation (SVPWM) can produce equivalent voltage vector with any phase in a control period, a method of calculating expected voltage vector was proposed for improving the effectiveness of DTC, and a PI controller was used instead of conventional DTC system' s hysteresis comparator to construct a DTC system base on expected voltage vector. The comparison experiments showed that the proposed direct torque control strategy has lower current harmonics, lower torque and flux ripple and the speed responsibility, which is quicker than the conventional DTC, has smaller steady-state error.