Research On Harmonic Current Suppression Strategy Of Dual Three-phase Permanent Magnet Synchronous Motor

Compared with the three-phase permanent magnet synchronous motors(PMSM),dual three-phase permanent magnet synchronous motor have the characteristics of high reliability,small torque fluctuations and strong fault tolerance.It is suitable for marine,aerospace and electric vehicle applications.However,due to the existence of harmonic subspaces in the dual three-phase PMSM,small voltage distortion will cause excessive current harmonics.In this paper,the dual three-phase PMSM is taken as the research object,and the control algorithms are designed to suppress their current harmonics.Firstly,the structure model under six-phase stationary reference frame of the dual three-phase PMSM have been deduced and explained,then the model is decoupled by the vector space decoupled transformation and build the corresponding simulation model.The influence of the dead zone of the inverter on the current harmonics of the dual three-phase PMSM is analyzed through mathematical formula derivation.A simulation model including the dead zone of the inverter is built in Simulink under the vector space decomposition reference frames,and the current harmonics of dual three-phase PMSM are simulated and compared.Secondly,the basic principle of the quasi-proportional resonant(PR)controller is analyzed in detail and why the quasi-PR controller is used to replace the traditional PI control in the harmonic sub-plane.In view of the traditional PI control is difficult to track and adjust the periodic signal without static error on the harmonic sub-plane,the Bode diagram is used to analyze in detail how the quasi-PR controller tracks the harmonic sub-plane without static error and the influence of various parameters on the system regulation.In order to simplify the system and reduce the difficulty of parameter adjustment,two quasi-PR controllers are connected in parallel,and their mathematical model and Bode diagram are given to verify the feasibility.Because the effect of using a quasi-PR controller alone to control the current harmonics on the harmonic sub-plane is difficult to achieve the desired effect,the feed-forward control is used to further suppress the harmonic currents on the harmonic sub-plane.Finally,Because the feed-forward control based on quasi-PR needs more mathematicalcalculation and parameter adjustment.This thesis proposes a linear auto disturbance rejection control method which does not depend on the specific mathematical model to suppress the harmonic current on the harmonic subplane in the full frequency domain,deduces the mathematical model applied to the harmonic subplane and carries out simulation verification.Simulation verification was carried out in Simulink,and the inhibition effect of the two methods was compared and analyzed.