Loss-minimization control of vector-controlled induction motor drives

It is well known that the efficiency of induction motor drives under partial load can be improved via manipulation of its field. Among the numerous loss-minimization schemes proposed previously, the scheme that uses motor power factor as the main control variable has the advantages of high sensitivity and ease of implementation. But the problem of how the optimal power factor commands can be generated is not well documented. In this paper, a scheme that uses power factor control with automatic measurement of the minimum-loss power factor commands is proposed. A fuzzy logic compensator is included in the controller to improve the accuracy of the generated commands. The scheme is simple for implementation and does not require an a priori knowledge of motor parameters. Experimental results have validated the effectiveness of this scheme to minimize the motor operating losses.