A DSP-Based Vector Control System Of Multiphase Induction Motor

The use of multiphase induction motor for industrial drives presents several advantages over the conventional three-phase drive, such as improved reliability, reduction on the power ratings for the static converters and harmonic reduction. For these reasons, multiphase induction motors are widely used in high power applications. Although this topology has received some successful application recently, there are a lot of problems about its control method in the theories and practices that deserved to be researched.The performance of AC variable speed drive system has been improved greatly since field-oriented control is applied. Firstly, in this paper, the principle of Field Oriented Control(FOC) is illustrated. And the Field Oriented Control system of conventional three-phase induction motor is realized in Matlab/Simulink. The simulation results show that the scheme is desirable. Secondly, the effect of output voltage's time harmonic on the motor, fed by multiphase inverter is worked over, and a matrix transform between the nature base and harmonic base is proposed. Using this matrix transform, the model of multiphase induction motor in the nature base can be transformed to several mutual vertical planes, the harmonic base space. And then the machine model of the multiphase on the harmonic base is developed. It is proved that in the static two-phase coordinate, machine model of induction motor with any number of phases is accordant, which is the theory foundation for applying the almost mature three phase high performance control strategy to machine adjustable drive system. Based on the static two-phase coordinate machine model, The stability study of a multi-phase (six-phase) induction machine has been performed by applying the eigenvalues stability criterion to the small displacement equations obtained by linearization about an operating point. Thirdly, taking a dual three-phase induction motor for example, coordinates transformation is derived. Based on it, the machine model of dual three-phase induction motor is developed. Then the FOC system of dual three-phase induction motor is realized in Matlab/Simulink. The simulation results show that is much better than the conventional three-phase induction motor system.Finally a drive device based on DSP and IPM is designed in this thesis, especially the design of the DSP minimal system, current detecting circuit, speed and position-acquiring circuit, power circuit based on IPM are further researched. The software frame of the system is introduced and the flow chart is given.