Three-level Inverter Direct Torque Control of Induction Motor Based on Virtual Vectors

  • Tan Zhuohui (Dept. of Electrical Engineering, Tsinghua Univ.,) ;
  • Li Yongdong (Dept. of Electrical Engineering, Tsinghua Univ.,) ;
  • Hu Hu (Dept. of Electrical Engineering, Tsinghua Univ.,) ;
  • Li Min (Dept. of Electrical Engineering, Tsinghua Univ.,) ;
  • Chen Jie (Dept. of Electrical Engineering, Tsinghua Univ.,)
  • Published : 2001.10.01

Abstract

Multilevel inverter has attracted great interest in high-voltage high-power field because of its less distorted output. In this paper, a direct torque control (DTC) technique based on a three-level neutral-point-clamped (NPC) inverter is presented. In order to solve the intrinsic neutral-point voltage-balancing problem and to obtain a high performance DTC, a special vector selection method is introduced and the concept of virtual vector is developed. By using the proposed PWM strategy, a MRAS speed sensor-less DTC drive can be achieved without sensing the neutral-point voltage, The strategy can be verified by simulation and experimental results.

Keywords