Research On Control System Of Dual Three-phase PMSM

Due to the limitations of the traditional three-phase motor drive system,it can not meet the practical occasions of high power level,good speed regulation performance and high reliability requirements.While the multi-phase motor drive system has obvious advantages at these occasions.In this paper,a dual three-phase PMSM(under the paper celled as dual three-phase motor)with a stator winding differ by 30 degrees as the research object,and studied in depth on mathematical modeling,harmonic analysis and control strategy.First this article introduces the mathematical model of the dual three-phase motor in the natural coordinate system,then establishes the mathematical model in the rotating coordinate system by dual d-q transformation and space voltage vector decoupling transformation.Based on the space vector decoupling transformation,the vector control strategy of dual three-phase permanent magnet synchronous motor is studied in detail.Including traditional Two-vector SVPWM algorithm and Four-vector SVPWM algorithm.The four-vector SVPWM algorithm solves the problem of uncontrollable z1-z2 sub-plane harmonic current in the traditional two-vector algorithm,which effectively suppresses the harmonic current on the stator and greatly reduces system losses.Then,in order to improve the dynamic and static performance of the system and solve the problem of large harmonic currents in the z1-z2 sub-plane when the dual three-phase motor is running,using fuzzy PI controller and proportional resonance controller(PR controller).By optimizing the speed loop through fuzzy control theory,combining PI control technology with fuzzy theory,a fuzzy PI controller with self-tuning parameters is designed to replace the PI regulator in the speed loop to improve its dynamic and static performance.The PR controller can be used to track the AC signal in the variable with zero static error and to suppress the 5th and 7th harmonics of the daughter board,reducing the system losses of the dual three-phase motor.Finally,aiming at the inherent shortcomings of the four-vector SVPWM control strategy:the asymmetric PWM waveform,the large amount of calculation and the large switching loss.A simple and effective control strategy is proposed,that is a carrier pulse width modulation strategy that injects dual zero-sequence voltage.We call it a dual zero-sequence injection PWM control strategy.