Research On Nonlinear Compensation Control Of Marine Permanent Magnet Propulsion Motor

In recent years,with the development of ship AC speed regulation system and power electronics technology,more and more attention has been paid to environmental protection in the world.It has become a major trend to adopt electric propulsion system as marine active propulsion device.In this paper,permanent magnet propulsion motor(PMSM)is taken as the research object,and the non-linear problems in PMSM control system and the non-linear suppression algorithm are studied.Firstly,the structure of PMSM is analyzed,and the mathematical model of PMSM based on three-phase static coordinate system and two-phase rotating coordinate system is established.The control strategy and pulse width modulation strategy of AC motor are studied,and the advantages and disadvantages of different control strategies are summarized.Secondly,the non-linearity of current sampling is deeply analyzed.Based on the digital low-pass filtering algorithm,an algorithm for estimating the error current of speed difference is proposed,which effectively suppresses the speed and torque ripple of closed-loop system caused by current sampling error.Aiming at the non-linearity of the inverters in the control system,the formation mechanism of the dead-time effect of the inverters and the influence of the closed-loop system voltage,phase current and speed under the dead-time effect are analyzed.By analyzing the dead-time and disturbance voltage of the inverter,the Deadtime compensation algorithm based on time compensation and disturbance voltage compensation algorithm are adopted.On this basis,an on-line adjustable Deadtime compensation algorithm for disturbance voltage is proposed,which avoids the influence of the phase current detection accuracy of the traditional dead-time compensation algorithm on the dead-time compensation effect.By comparing and analyzing the three algorithms,the feasibility and efficiency of the improved disturbance voltage dead-time compensation algorithm are verified.On the basis of error current and dead-time compensation of inverters,a sensorless control algorithm based on generalized second-order integrator is studied,which further improves the control accuracy of sensorless control.On the basis of theoretical analysis and simulation verification,a set of PMSM for ships is built and an experimental platform is designed.Experiments under various working conditions are carried out on the experimental platform.The output waveforms of voltage,current and speed are measured.The feasibility and good dynamic and static performance of the algorithm are verified in the actual system.The influence of non-linear factors in the system is restrained and the control performance of the system is improved.