Research On The Drive Technology Of Nine-phase Permanent Magnet Motor For Marine Electric Propulsion

In conditions of low voltage high power application, total power of each switch transistor can be reduced as the phases of multi-phase motor share the currents, so it is very suitable for multi-phase motor to be used in such occasions where the supplied voltage are limited as marine electric propulsion system. During multi-phase motors, the three Y 20°shifted nine-phase permanent magnet synchronous motor(PMSM) shows more fault-tolerant ability, smaller torque vibration and more flexible control method than six-phase motor. So it is increasingly popular in new energy motor, rail and ship drivers and other fields. Meanwhile the mathematical model and drive control strategies for nine-phase motor with non-sinusoidal windings are correspondingly complex. And its control method has not been improved perfectly up to now, more studies should be carried out. In this paper, treating the triple Y 20°shifted nine phase PMSM as the research object, some studies on such key problems as motor mathematical model, control strategy and modulation algorithm have been done as follows:Firstly, the magnetic potential of multi-phase permanent motor was analyzed and the Clarke converter matrix of non-sinusoidal windings was derived by means of analyzing the harmonic subspaces in multi-phase permanent motor, furthermore, the mathematical model of nine phase motor in rotating coordinate system was derived out.Secondly, the application of CPWM for use in multi-phase was researched, based on the three phase carrier PWM(CPWM) theory. Combined with multi-phase subspace vector control strategy, the current loop control block diagram for winding non-sinusoidal triple Y 20°nine-phase motor was designed. Then the vector control in fundamental and multi-subspace was tested in simulation system of Matlab/Simulink, the results showed that the later control strategy can guarantee well operation and fast response of the system for environmental disturbance.Furthermore, in order to carry out studies about nine phase PMSM, a general hardware platform based on DSP+FPGA is designed. Some tasks were allocated for DSP and FPGA according to the platform. By use of FPGA, multiple PWM generator was configured out and the flowchart of control software in DSP was completed.At last, experiments in the former platform were carried out and the HDL and other major design were proved to be effective during the experiments. The results showed that some functions can be implemented and the preliminary conditions of multi-space vector control algorithm for triple Y 20°shifted nine-phase motor were possessed.