A Consideration on Field Acceleration Method and Vector Control of Induction Motor

Abstract

The two axis theory and the vector control based on this theory are well known. On the other hand, Yamamura proposed the phase segregation method (spiral vector method) for the analysis of induction motor, and suggested the field acceleration method (FAM). In this paper, the comparison of these analytical and control methods is investigated.
At first, the equations from which the phase segregation will be derived are interpreted. In these equations, the information from 3-phase stator and rotor equations is involved. Secondly, it is clarified that the vector control system for constant rotor flux is a goal of T-I type FAM which is derived from a zero transient term condition. By using the T-I type transient equivalent circuit, the vector control system is easily obtained, because the circuit is the same as steady-state one when the amplitude of rotor flux is constant. The analytical solution of transient response for the vector control system is obtained for arbitrary initial conditions. Furthermore, the stability of T-II type FAM especially for the effect of stator resistance change is discussed by computing the torque transfer function. When the stator resistance is correctly estimated, the pole-zero cancellation occurs on the imaginary axis.