Research On Space Vector Pulse Width Modulation Strategy For Double Three-phase PMSM

Compared with the traditional three phase motor, multiphase motor has outstandingadvantages of high low supply in low-voltage, small torque ripple and high reliability andso on. Therefore, multiphase motor has been highly valued because of its superiorperformance in the cases of limited supply voltage and high power level and reliability,such as ship propulsion system, nuclear power plant water circulatory system and so on.This thesis chooses six-phase permanent magnet synchronous motor with dual Y shift30°winding as the research object elaborates its mathematical models and analyzes its workingprinciple in detail. Furthermore the thesis proposes a four-vector SVPWM algorithm toreduce harmonic currents of the stator, therefore reducing noise and vibration. The maincontents are as follow:Firstly, a mathematical model of permanent magnet synchronous motor in the twophase rotating coordinate system is built in the thesis, and on this basis, a simulation modelbased on id0vector control is also established.Secondly, the thesis introduces the basic principles of SVPWM technology, elaboratesthe development of SVPWM technology and its research status at home and abroad, andproposes a simplified two-vector SVPWM algorithm. This method simplifies thecalculation process, overcomes the shortcoming of the large amount calculation oftraditional SVPWM algorithm, thus facilitating the realization of engineering.Furthermore, on the basis of the two vector SVPWM algorithm, traditional SVPWMalgorithm stator current harmonics uncontrollable defects, proposed a four-vector SVPWMalgorithm. This algorithm ensures that the voltage is zero in subspace synthesis, inhibitingthe harmonic subspace wave current, which can effectively reduce the harmonic currentsof the stator.Finally, a double three-phase permanent magnet synchronous motor frequency controlsystem model is established based on Matlab/Simulink simulation software. Through the comparative analysis of the current waveform spectrum between adjacent four-vectorSVPWM algorithm and the traditional maximum of two-vector modulation SVPWMalgorithm, it shows that harmonics concentrated in the switching frequency and itsmultiples, especially harmonic amplitude of the current at the twice switching frequency ismaximum. It can be achieved that adjacent four-vector SVPWM algorithm effectivelyreduces the magnitude of the current harmonics. At the same time, this SVPWM algorithmreduces the magnitude of the current harmonics at switching frequency and its multiples,thus effectively reducing the noise and vibration of the motor.