| Abstract |
Almost all papers explain rotor time constant influence in field-oriented systems giving us more and more mathematical expressions without show explicitly control variables behavior either in steady- and transient-state for tuned and detuned operations. This work intends to mix either mathematical analysis and more exaustly simulated and experimental results of this problem to give a didactic explanation for all that are studying this problem. It is known that in field-oriented AC motor control, rotor time constant (Tr) knowledge is crucial to obtain high performance because it's important to know instantaneous position of rotor flux that depends on (Tr). Low frequency response, speed oscillations and the loss of input-output torque linearity are the cosequences for detuned operation, decreasing motor drive efficiency. In this paper, a nonlinear mathematical model of a three-phase squirrel-cage induction motor is linearized under vector control and it results in a perturbed model that will clarify torque behavior for a rotor time constant decrease or increase in drive system. Expressions are derived to analyze effects in steady-state operation and effects in transient situations. These effects are experimentally verified with a microcomputer induction motor drive system and with simulations of same system. |
