Investigation On The Vecter Control Of Dual Y Shift30Degree Permanent Magnetic Synchronous Motor

Compared with three-phase motor drive system, multi-phase motor drive system has the advantages such as low power-high power, high reliability. A dual-three phase permanent magnet synchronous motor(PMSM) is one of the most popular multi-phase motor. This paper has researched on the theory of the dual-three phase PMSM in detail and the control technology of SVPWM and operation in phase-fault conditions.The paper analyzed the winding structure of multi-phase machine firstly, using space vector decoupling, the dual-three phase PMSM was decoupled from six-dimension to three two-dimensional orthogonal sub-planes, and the mathematic model under harmonic-base for the dual-three phase PMSM was built. Then, the time and space harmonics of magnetic potential and the harmonic torque of the machine supplied by six-phase inverter were analyzed.After the transformation from the stationary coordinate system to synchronous reference frame system with the permanent flux linkage is in d-axis, the dual-three phase PMSM’s decoupling control can be realized by setting the reference of d-axis stator current to zero. Space vector PWM technisque can be used to control the torque and stator harmonic current at the same time. On the basis of this PWM technisque, a detailed study of the selection and distribution of zero vectors in continuous modulation and discontinuous modulation are presented in this paper. The simulation results show that a smaller torque ripple can be received by using the continuous modulation, while the number of switching times can be significantly reduced and less stator current harmonic content can be received by using the discontinuous modulation.This paper also analyzed and researched the operation of dual-three phase PMSM with phase fault conditions. The dynamic model with one phase open fault for the dual-three phase PMSM was established. The performances variation under phase fault was analyzed in detail. Aimed at dual-three phase PMSM asymmetrical running, two compensating control strategies were presented to restrain the torque fluctuation. The first method based on invariable stator magnetic potential by adjusting currents amplitudes and phase angles. The problem of this method is that it doesn’t consisder the changing of the electromagnetic parameters. The second method using the winding equivalent transforming, therefore, the asymmetric system was transformed into symmetric system, then the flux linkage orient decoupling control was achieved with phase fault condition.