Magnetization Curve Identification of Vector-Controlled Induction Motor at Low-Load Conditions

摘要

In many drives the induction motor torque is transferred to the load through complex mechanical connections which produce an initial load. In such cases, to identify the magnetization curve by the no-load test it is necessary to decouple the motor from the transfer gear what is expensively and time-consuming. In an attempt to avoid the motor mechanical decoupling in the case of hoist crane systems, in this paper a method is proposed for the magnetization curve identification of the indirect rotor flux oriented (IRFO) induction machine at low-load conditions. Two flux controllers with estimated feedback quantities are added to the basic structure of the IRFO control drive. One of these controllers is used to control desired operating point on the magnetization curve and the other for on-line adaption of the reference frame position. The proposed algorithm is implemented in a commercial drive as a part of the self-commissioning module. Afterward, the magnetization curve of the 22 kW induction motor was identified and compared with the one obtained by the no-load test. The method sensitivity to the load torque and the transient inductance has also been considered.%Brojni su primjeri pogona u kojima se moment asinkronog stroja prenosi na radni mehanizam preko mehani?kih reduktora koji mogu predstavljati zna?ajno optere?enje motoru i u re?imu neoptere?enog pogona. Da bi se u takvim slu?ajevima odredila krivulja magnetiziranja iz pokusa praznog hoda nu?no je odspojiti motor od reduktora ?to je skupo i vremenski zahtjevno. U poku?aju da se izbjegne mehani?ko odspajanje motora kod dizali?nih sustava, u ovom je radu predlo?ena metoda za odre?ivanje krivulje magnetizranja vektorski upravljanog asinkronog motora kod malih iznosa optere?enja. Dva regulatora ulan?enog toka s estimiranim veli?inama u granama povratne veze dodani su osnovnoj strukturi vektorski upravljanog pogona. Jedan od regulatora koristi se za upravljanje ?eljenom radnom to?kom na krivulji magnetiziranja dok se drugi koristi za pode?avanje referentnog polo?aja vektora toka rotora. Predlo?eni algoritam implementiran je u komercijalnom ure?aju kao jedan od samopode?avaju?ih modula koji se koriste prilikom pu?tanja u rad pogona. Nakon toga je opisanim postupkom odre?ena krivulja magnetiziranja 22 kW asinkronog motora i uspore?ena s krivuljom dobivenom iz klasi?nog pokusa praznog hoda. Tako?er je razmotrena i osjetljivost metode na iznos momenta optere?enja i tranzijentnog induktiviteta.