Parameters Determination And Electromagnetic Field Analysis Of Canned Solid-Rotor Induction Motor

The purpose of this thesis is to study of electromagnetic theory of the canned solid-rotor induction motor, with the emphasis on the determination of equivalent circuit parameters, electromagnetic energy conversion principle and the performance calculation of the motor. The practical equivalent circuit of the canned solid-rotor induction motor and analytic expressions of equivalent circuit parameters are precisely derived. In this thesis, the electromagnetic field finite element method is also used to obtain the value of equivalent circuit parameter.A brief summary of the present development of the induction machine with solid conductor structure and the research status of the canned solid-rotor induction motor is made in this thesis. And illustrates the importance, content and methods of this research. The2D-Multilayer general analytical model of the canned solid-rotor induction motor is built by the2D-multilayer electromagnetic field theory. Combining the solution of the electromagnetic field with equivalent circuit, the rotor equivalent parameters of canned solid-rotor induction motor is deduced.With the basic concept of mutual inductance, the mutual leakage inductance of the motor is obtained by equivalent magnetic circuit method. Then, the mutual inductance coupling equivalent circuit is decoupled with reasonable simplification at normal load range of the canned solid-rotor induction motor. As the equivalent resistance expression of stator can is deduced by "Virtual cage" method and the2D magnetic field analytical method, the well-defined practical equivalent circuit of the motor is derived. Then the use of the ractical equivalent circuit and its analytic parameters are discussed by an application example.The steady state operation performance and equivalent-circuit parameters of induction machine with different rotor structures are analyzed by electromagnetic field finite element method. As the impedance of rotor is calculated by the Poynting vector on the surface of rotor in time-harmonic field, this method can be used for the induction machine with different rotor structures. Taking examples of a normal induction machine (Y2series) and a caged solid rotor induction motor, the precision of proposed method is confirmed by the experimental testing result. Then, the derived equivalent circuit parameters of canned solid-rotor induction motor is verified by the proposed method.Losses of the canned solid-rotor induction motor are discussed by both the time- harmonic and time-varying finite element analysis, the influence on losses by harmonic neld is obtained by comparison. Two of the iron loss calculation models combined with finite element method are presented, which are the Bertotti loss model and Loss Surface dynamic-hysteresis model. Their calculation accuracy on the loss determination of motor with both alternating magnetization and rotation magnetization are compared with test results. The iron loss test method for the single-phase induction machine is also studied in this thesis. By the intense research on the asymmetric operation of asymmetrical single-phase induction machine using the symmetrical components method, an improved iron loss test method is proposed.