The Design Of Drive System And Research Of Engineering Application For Six-phase Permanent Magnet Synchronous Motor

Compared with three-phase motor, multi-phase motor has the advantages, such as, low voltage with high power, reducing the torque ripple and high reliability and so on. Multi-phase motor drive system is very suitable for high power rating and high reliability, such as ship propulsion system, pure electric and hybrid electric vehicle traction system and so on. Multi-phase permanent magnet synchronous motor drive system is regarded as a new application field, the control method in the application of theory and practice has become a research hotspot. Based on a dual-six phase permanent magnet synchronous motor which is the research object in this paper,mainly aims at the analysis and research of motor mathematical model, the SVPWM modulation technology, and the initial position angle detection technology, etc. The analysis methods and conclusions in this paper can be generalized to analyze other multi-phase permanent magnet synchronous motor, and provided theoretical basis and creating engineering value for further study of multi-phase permanent magnet synchronous motor. The thesis mainly worked as follows:1) Based on winding function theory knowledge, mathematical expressions of winding functions and the air gap magnetic conductance functions are derived which are about a dual-six phase permanent magnet synchronous motor including two forms of winding sinusoidal and non-sinusoidal distribution, and the mathematical models of two types of winding are established in natural coordinate system and rotating coordinate system.2) As for two conditions containing sinusoidal and non-sinusoidal winding distribution in six-phase permanent magnet synchronous motor with two Y-connected windings displaced by 30°, fundamental control system and multidimensional vector control are analyzed and researched for drive system.3) In this paper, the PWM modulation technology mainly aims at six-phase motor drive system. After analyzing and studying two PWM modulation technologies including BFV-SVPMW and carrier-based PWM, the new SVPWM strategy with optimal switching frequency is presented, which contains lots of advantages, such as,high utilization radio of DC voltage, periodic symmetry and the power devices only switch once in one PWM period. The results of the study have been simulated andverified through the experiments.4) According to the structure feature of space winding in six-phase permanent synchronous motor, the neutral point will not be isolated when double Y shift 30 degree. The method to detect motor phase sequence is investigated after testing back EMF of motor and two technologies to detect rotor initial position angle are presented.The results of the study have been verified through the experiments and projects.The above results of the study was applied to the project of ship propulsion multi-phase motor drive software development in CNR Yongji xinshisu Electric Co.,Ltd.,which optimized phase current waveform,accurately detected phase sequence and initial angle of motor.