Research On Rare-earth Permanent Magnet Starter-generator Integrated Device And Control Technology For Vehicle

In the electrical system of the automobile, the starter and generator are two independent electrical installations. This paper designed a flywheel-typed outer rotor starter generator installed on the engine crankshaft to perform the functions of starter and generator, which can reduce body weight, save space and reduce costs. The main contents of the paper are as following:1. Calculating the structure parameters and the electromagnetic parameters of the integrated device about motor starter and power generation. The flywheel permanent magnet outer rotor structure is designed, which can prevent the permanent magnet material of falling off and have good heat dissipation performance. Stator structure adopts the fractional slot structure, while start winding and the power generation winding winds adopts the same slot structure, for the dual-winding structure takes into account of the characteristics of the quick start performance when the motor runs in at large current and the stable direct current outputting when generator works in high speed condition. The paper emulated the motor’s magnetic field by means of finite element method, optimized motor structure parameters according to the results, and reduced magnetic leakage to improve material utilization.2. Establishing a mathematical model of permanent magnet brushless direct current motor, deeply analyzing the main influence factor of the starting process. The direct torque control system of permanent magnet brushless direct current motor is designed on the basis of studying the theory of direct torque control. After establishing torque and flux linkage algorithm model in the stator stationary coordinate system, adopting dual hysteresis loop structure on the magnetic flux and the torque, and selecting the appropriate voltage vector responding to torque error, the direct control of the electromagnetic torque is performed. The control system simulation model is established, and the simulation results show that the control scheme can effectively reduce the torque ripple of the starting process.3. Completing the system of the direct torque control system hardware design with use the core TMS320F2812. The control circuit for stabling voltage is designed, simulation is performed with the software Mutisim10. And the simulation results shows the stably output on 42V DC within wide speed variable load can be generated by the motor. After the debugging experiment about the starter-generator and its controller, the experimental results verified the starter-generator index having achieved the design requirements.