Study On Design Theory And Control Method Of Permanent Magnet Type Retarder In Automobile

Permanent magnet type retarder, working on the principle of electromagnetism, is a device for retardation of running automobiles. Being performed in the condition of no contact (without friction), the smooth process of deceleration is guaranteed, the safety performance is enhanced, and the valued lives of the brake plate and naves are greatly prolonged, therefore, the retarder has been employed popularly on the automobiles in advanced countries. As it is lack of mature theory at home as well as reasonable evaluation system both at home and abroad. The purpose of the paper in fact is to give a support in both theory and technology for in country enterprises to develop the retarder that they have their intellectual property. The main research structure and highlights of the paper are as followed:1. Magnetic field and braking torque analysisBy means of FEM, the analytical solution of the magnetic field can provide a most valuable eddy current computation method, eddy current density in the rotor. Meanwhile, braking torque is obtained with eddy current losses.2. Building leakage flux modelThe research work is aiming at optimization design and decreasing flux leakage. Using magnetic methods, flux leakage model was established on the model of permanent magnet retarder, which deduced equations on design parameters. Considering the complex function relationships among flux leakage factors, interval mathematics was used to optimize design for permanent magnet retarder. Based on Tschernikow algorithm, nonlinear equations of magnetic flux leakage were simplified into linear equations. 3-D finite element model on flux leakage and test show the rationality of design parameters and interval mathematics. The results show that H_PM and g_e efficiently influence magnetic flux leakage coefficient K.3. Multilevel design methodsA complete multilevel model for complex design problem with a large number of design variables and constraints is built. To solve the multilevel design problem, a new coordination method is proposed and its mathematics proof is also given in this paper. By mapping them into non-free hypergraphs, the original design problems are transformed into non-free hypergraphs decomposition problems. These non-free hypergraph decompositions account for computational demands and resources.4. Hierarchical control According to the recent trend of high speed and heavy load in traffic, permanent magnet type retarder is highly desired to obtain hierarchical control. This paper reports the basic idea, construction design of hierarchical control.5. Thermal-magnetic coupled model and the influence of material propertiesThermal field analysis for permanent magnet type retarder fin is its kernel design issue. A weakly coupled phenomena between magnetic and temperature fields was investigated in retarder. Eddy current losses are inner thermogenesis of temperature field governing equations. Coupled thermal-magnetic fields mathematic model with multi-factor effects was established in the paper. The model gives some instructive directions to decreasing temperature in rotor and fin design from several coupledinfluencing factors.The major contributions in this paper are that:1. Magnetic flux leakage model is established, and influcing factors are analyzed, and decreasing flux leakage in non-working condition.2. Based on the newly multilevel design method, permanent magnet type retarder is designed. Thus,a large number of design variables and constraints is solved.3. In practice, the newly hierarchical control is developed.4. Coupled thermal-magnetic model is established, and effects of parameters are analyzed. This method provide a novel viewpoint to sheat-dissipating DesignThis paper proposed that a newly design method for permanent magnet type retarder. The experimental results agree with the theoretical one essentially, prove the feasibility of the theory of design. Finally, some suggestions are given for future study and a bright future of hierarchical control.