Online Identification of the Mutual Inductance for Vector-Controlled Induction Motor Drives

Mutual inductance of an induction machine may vary considerably when the flux reference varies. An important and frequent application of a variable flux reference is the operation in the field-weakening region. Standard assumption of constant mutual inductance is no longer valid and it becomes necessary to compensate for the mutual inductance variation. This paper proposes a novel method for on-line mutual inductance identification in vector-controlled induction machines. The method is characterized with a very simple structure, ease of implementation, very low parameter sensitivity, and the capability to provide an accurate estimate under both transient and steady-state operating conditions. Full experimental verification of the proposed scheme is provided and a number of potential applications in a vector-controlled induction motor drive are discussed.