Research On Analysis And Optimal Design Of Novel Synchronous Motors

The synchronous motor is a complex, nonlinear and dynamic system, which exists widely in many fields such as aviation, traffic and architecture. It is very important for the development of modern industry to study on novel configurations, operational principles and parameters calculation of synchronous motors. Optimal design is one of the most important steps in motor design, which influences directly on the cost and performance of the motors. So analysis and optimal design of novel synchronous motors have become the new research focus of electric motor field.Based on reasonable hypothesizes, finite element method (FEM) is used to analyze three novel types of synchronous motors- the long stator motor, the linear reciprocating generator and the axial field composite motor. A series of relationships among dimensions, parameters and performances of motors are obtained. Then a new optimal design method is proposed based on the optimal design methods existed. The proposed method overcomes the disadvantages such as time-consuming and narrow applicability of conclusions. And it has advantages of accurate calculation, convenience and wide applicability of conclusions. Compared with the motors existed, the optimized novel motors have higher power density and efficiency. The main works are listed as follows:1. A new optimal design method which combines two optimal methods existed is proposed. The effects of main dimensions on the motors' performances are firstly analyzed by FEM one by one. And best individual dimension is got using induction, analysis and contrast, on the condition that other dimensions are unchanged. Then calculation formulas of the performances can be acquired by polynomial fitting in term of the FEM results. Using the formulas as mathematics model, global optimal designs of those motors are carried out at last. This new optimal design method not only can get general conclusions and relationships between motors' dimensions and performances. It also can narrow the analysis range of optimal design and reduce the calculation time needed. Compared with other analysis methods, the proposed method can characterize the motors more precisely. The analysis results are satisfactory.2. A novel linear reciprocating generator is optimized by the proposed novel optimal design method. The influences of the main parameters such as the outer dimension, PM height and core diameter on the EMF are analyzed systematically by the FEM. And the relationships between the performance and the parameters are obtained. Also, some design criteria and formulas are summarized through analyzing magnetic field and EMF of generators with different dimensions. Compared with an internal PM reciprocating generator, the external one optimized has better performance and lower cost. When their outer dimensions are both 31mm and operated at the same speed of 1m/s, the efficiency of the external one is 1.04 times greater than that of the internal one. However, the cost of the former is only 97% of the latter.3. The long stator motor and the axial field composite motor are analyzed systematically and optimized by the proposed novel optimal method. Based on the FEM analysis results, calculation formula of the EMF, inductances and force are deduced by the multinomial fitting and the Fourier decomposition method. The influence of different parameters on the motor's torque and the EMF is analyzed in detail. Then general conclusions are gotten. These analytical results show that the change of the slot width and pole pitch affect the performance of the motors greatly. It also demonstrates that skewing poles could efficiently decrease the torque ripple of PM motors. In order to simplify the 3D FEM analysis of the axial field motor, a new calculation method is proposed. In this method, only 2D FEM and a correction formula are needed. The FEM simulation and experiment results all prove that the proposed method is effective.