Analysis And Research Of Double-rotor Permanent-magnet Doubly Salient Motor Based On The Equivalent Variable Permeance-networks

Due to the increasingly serious environmental pollution and the energy crisis, the hybrid electric vehicles(HEVs) have attracted considerable attention from the governments for its merits like fewer requirements for the battery, abundant operating modes, and relatively high efficiency. Consequently, the global auto manufactures invest a lot of manpower and material resources to research and develop multiple types of HEVs. The doubly salient permanent magnet double-rotor motor inherits the merits of the doubly salient permanent magnet motor, e.g., high power density, high efficiency, simple and robust rotor, and easy thermal management potential. Furthermore, the power distribution of the ICE and the motor can be realized by the non-contact electromagnetic coupling, which has aroused much focus on the hybrid electric vehicles field. However, due to the partial magnetic saturation, the non-linear characteristics of the magnetic material and the complex change of the field distribution, it makes the analysis method which based on the traditional magnetic circuit far away from accuracy. On the other hand, the statistics preparation and the simulation time of the finite element analysis method is too long, resulting from the high integrity, relatively complex structure, and various design parameters of the DR-PMDS motor. Consequently, this thesis proposes the equivalent variable presence networks(EVPN) method which is applied to the structure design, parameter optimization, and electromagnetic performance analysis of the DR-PMDS motor. This method not only inherits the simplicity and the rapidity of the conventional magnetic circuit method, but also incorporates the concept of field to enhance the calculation accuracy, which possess potential research value and exploration space. The main achievements of this thesis are listed as follows:1. This thesis analyzes the advantages when the DR-PMDS motor is applied to the HEVs according to the requirements of the HEVs driving system and the characteristics of the doubly salient permanent magnet motor. And the design, optimization, and analysis of the motor are realized based on the EVPN method.2. The magnetic circuit law required in the EVPN was obtained by borrowing the concept of the electric circuit analysis method, such as: Ampere circuital law, Ohm’s law, and Kirchhoff’s law. The equivalent magnetic conductivity of the armature windings, permanent magnet, air-gap, as well as the stator and rotor are calculated according to the magnetic circuit law and the characteristics of the DR-PMDS motor, thus the EVEN model and the corresponding nodal magnetic potential equation of the proposed motor is built.3. The EVEN model of DR-PMDS motor is solved based on the VC++6.0 software platform. The overall structure of the program is built according to the flow chart, which utilize the Gauss-Seidel iteration method to solve the equation and the Lagrange interpolation method to fit the B-H curve of the nonlinear magnetic material. And the magnetic flux, back-EMF, air-gap field flux density, and the torque is achieved by the aforementioned method. The results of the EVPN method are validated by the finite element analysis method, especially the effectiveness and the accuracy of the method.4. This thesis proposes a joint design and optimization method which combines the EVPN method with the finite element analysis method. The leading design parameters are determined and the optimized motor specifications are obtained by the method. A prototype machine of the DR-PMDS motor is manufactured and the experiment platform is built. The experimental result not only shows the reliability and validity of the proposed design optimization method, but also proves the accuracy and the effectiveness of the EVPN method with respect to the electromagnetic performance analysis.