Abstract
Vector control technique rapidly increases the number and spreads the fields of applications of induction motors. For designing and realizing excellent vector controllers for induction motors, it is necessary to analyze and understand the motors deeply. This paper presents vector analysis for vector control of induction motors in much more unified manner than conventional.
First of all, mathematical model of the motors is shown, which is described on vector basis rotating with arbitrary angular velocity. By using this model, instant-time relationships between input power, motor inner power and mechanical output power are analyzed in general manner and their clear physical meanings are given. Next, it is generally analyzed from view points of energy transfer that constant control of magnitude of secondary (or primary) flux is quite proper. This propriety is also analyzed from view point of torque control in vector control method by simple but general way. Finally, relationships between primary, secondary currents and secondary flux are analyzed in both general and flux controlled cases.
