Study on the structure and electromagnetic of claw pole motor for vehicle

Abstract

This paper introduces three kinds of hybrid excitation claw pole motor structure: Permanent magnet (PM) placed in the yoke (Model a), PM placed outer surface of the claw (Model b), PM between the claw (Model c).It analyze three kinds of claw pole motor on magnetic circuit and structure, then calculate electromagnetic characteristics of three kinds of structure with three-dimensional finite element method (FEM), the calculate results show that model c is the most suitable structure of claw pole motor for hybrid vehicles . Finally, no-load induced voltage of model c under different excitation current is analyzed by experiment. I. INTRODUCTION Due to its high space usage, compact structure, low cost and excellent regulated performance, the traditional claw-pole generator has become the mainstream product within vehicle motors. With the wide application of ventilation, air-conditioning, anti-lock braking system, electronic ignition device, automobile safety fault diagnosis system, information systems, entertainment products, etc., auto electric power requirement has rapidly increased to 1.5~3kW. Thus it request vehicle motors with high power density, high reliability, high torque density and wide speed range regulation. The traditional electromagnetic claw pole motor can not meet the requirements. The hybrid excitation claw pole motor has both permanent magnet motor and electromagnetic motor advantages (1). The reasonable Hybrid excitation structure can improve the power density and reliability of motor. II. ANALYSIS OF STRUCTURE AND MAGNETIC CIRCUIT The hybrid excitation claw pole motor with conventional stator, rotor magnetic field is composed of adjustable electrical excitation magnetic and constant PM excitation magnetic (2). This section mainly analysis of the advantages and disadvantages of the different hybrid excitation structure from two aspects rotor structure and magnetic circuit. Hybrid excitation structure should that the structure is convenient for processing, safe and reliable fixed permanent magnet, rotor flux is easy to adjust, no local magnetic saturation and air gap flux density maximum. As shown in Figure 1 for the three kinds of hybrid excitation claw pole motor structure. This paper will analysis and comparison of the three models from the structure, magnetic and air gap magnetic density, then find out the most suitable rotor structure of hybrid excitation claw pole motor for vehicle (3).