Research On Modeling And Optimization Of The Claw-pole Alternator For Automotive Application

One of the most important progresses in modern automotive equipment is the wide use ofalternator for automobile application. However, the alternator used at present is inefficient; the actualefficiency is only 50 percent when a typical Lundell claw-pole alternator is used. Analyzed andcalculated by three-dimensional finite element model (3D FEM), it can concluded that the serveleakage of the claw-pole alternator is the main case of inefficiency. How to optimize structureparameters for minimizing leakage of the Claw-pole alternator is the basic springboard of this paper.Optimizing structure parameters of the claw-pole alternator needs large-scale iterativecalculation, so nonparametric modeling is introduced to debase calculation cost. The purpose ofminimizing leakage is gained by optimizing the main structure parameters of the Claw-polealternator on the base of the high efficiency and exact nonparametric model.Modeling and optimization of structure parameters for the conventional claw-pole alternatorand the hybrid excitation claw-pole alternator are studied. The main research work in this paperincludes:1. On the base of fully understanding the electric characteristic of the claw-pole, base principleof the claw-pole alternator is analyzed by two reaction machine theory. The claw-pole rotor is themain difference compared to conventional synchronous alternator, and how to truly analyze andcalculate its design datum is the groundwork, and then direct design is used for claw-pole alternator.Parameter analysis is to deduce the immanent relation between the structure parameters and theperformance, and it is the base of parameter optimization, so parameter analysis for main structuresare implemented.2. The electromagnetic character of the conventional claw-pole alternator and the hybridexcitation claw-pole alternator are analyzed and calculated by three-dimensional finite elementmodel. The rationality of the 3D FEM is effectively show by the accordant results on theoreticcalculation and experiment, when the conventional claw-pole alternator and hybrid excitationclaw-pole alternator are on load. In order to settle the contradiction between the times of theoreticexperiment and the times of practical experiment for modeling, the orthogonal experimental designis introduced to gain the sample data for modeling. Furthermore, the rationality of the selectedparameters is verified by statistics theory.3. The necessity and possibility of the nonparametric modeling is analyzed. A large-scaleiterative calculation is needed for optimizing the structure parameters of the claw-pole alternator.Therefore, a more efficient model is wanted to improve the calculation efficiency. According to thelimitations of artificial neural network (ANN) and adaptive network based fuzzy inference system (ANFIS), support vector machine(SVM) is introduced in the nonparametric modeling of claw-polealternator, and it provides a high efficiency calculation means for optimizing the structure parametersof the claw-pole alternator. And then, nonparametric testing is accomplished for the SVM model.4. Optimization on structure parameters of the claw-pole alternator is a complicatedmulti-object; multi-restriction; non-liner, mixed multidimensional space problem, high efficiencyand dependable optimal algorithm is crucial. Particle swarm optimization(PSO)and Chaos areintroduced to optimize the structure parameters of the claw-pole alternator. Objective functionprovided by SVM model during the optimization course, the aim of minimizing leakage is gained.5. On the base of efficiency heightened in theory, optimization results are validated bymeasuring prototype using homemade testing platform at rated speed, and they are compared withthe calculation efficiency based on three-dimensional magnetic equivalent circuit model.