电力牵引传动系统的三电平直接转矩控制算法的半实物实验研究

针对高速动车组中三电平二极管中性点钳位(NPC)逆变器供电的牵引传动系统,探讨了一种基于PI控制器和60°坐标系空间矢量调制算法(SVPWM)的异步牵引电机低速域的直接转矩控制(DTC)驱动方案。直接转矩控制性能好坏的决定因素之一就是磁链观测器的准确性,为了获得较好的转矩控制性能,本文首先采用了一种改进U-I积分模型为定子磁链观测器,并给出了基于PI控制器的转矩控制器和磁链控制器设计方案;然后给出了60°坐标系下SVPWM算法的详细设计方案,与传统的SVPWM相比,该SVPWM能够有效地减小计算时间,并在此基础上,通过调节中点电位平衡因子的大小来分配冗余小矢量的作用时间,以达到平衡直流侧两电容上电压的目的;最后,通过基于Maltab/Simulink软件的仿真研究和TMS320F2812与dSPACE的高速动车组牵引传动半实物实验台的实验研究,验证了基于PI控制和60°坐标系SVPWM的三电平直接转矩控制算法的有效性和可行性。

Hardware-in-Loop Research of Three-Level Direct Torque Control Scheme for Electric Traction Drive System

A direct torque control(DTC) scheme of traction induction motor based on PI controller and space vector pulse width modulation(SVPWM) in 60° coordinate frame is adopted for traction system supplied by three-level diode neutral point clamped(NPC) inverter in high speed electrical multiple units(EMU).Firstly,in order to obtain a perfect torque performance,a modified U-I integration stator flux observer is presented,and the torque and stator flux control schemes based on PI controller are shown.Secondly,SVPWM in 60° coordinate frame is designed in detail,which can reduce calculation times effectively compared with traditional SVPWM.On basis of this,to balance the DC-link capacitors’ voltages,duty ratio times of redundancy small vectors are allocated by regulating neutral point control factor.Finally,validity and feasibility of the three-level direct torque control scheme based on PI controller and SVPWM in 60° coordinate frame are verified by Matlab/Simulink software simulation and Hardware-in-loop experiment of traction experimental prototype for high speed EMU based on TMS320F2812 and dSPACE.