Research On Control Strategy Of Underwater Robot Permanent Magnet Synchronous Motor Based On Speed Sensorless

At present,most of the permanent magnet synchronous motor(PMSM)used in underwater robots use traditional mechanical sensors to detect the rotor position,but the installation of traditional mechanical sensors has the following disadvantages: First,it will increase the rotational inertia of the rotating shaft of the motor;Second,the rotor the mechanical performance will be reduced;the third is to increase the size and volume of the motor,which is not suitable for the installation of underwater robots with limited space;the fourth is to increase the peripheral circuit connection,making the system unstable and susceptible to interference,especially water the high-salinity and high-humidity operating environment of the lower robot PMSM will affect the performance of mechanical sensors.Based on this,this paper focuses on the speedless sensor under the conditions of zero low speed,medium high speed and full speed range of underwater permanent magnet synchronous motors.In view of the phenomenon that it is difficult to detect the motor position angle when the PMSM for underwater robots is in the zero low speed section,the sensorless control of the high frequency pulse voltage signal injection method is studied,and the method is controlled by simulation experiments the effect was verified.At the same time,the filtering part of the method is improved,and the improved high frequency pulse voltage signal injection method is simulated.The simulation results show that the improved method improves the response speed of the system.Finally,the propeller load module is added to the system for simulation research.Aiming at the problem that the PMSM for underwater robots is in the high-speed section,the extended Kalman filter method requires huge calculations,and the model reference adaptive method requires accurate motor parameters.The speed sensorless control of the sliding mode observer method is studied.And the control effect of this method is verified through simulation experiments.Due to the problem of large speed fluctuations,the PI speed controller in the system was replaced with a sliding mode speed controller.The simulation results show that the sliding mode observer method based on the sliding mode speed controller reduces the speed fluctuation frequency.Finally,the propeller load module is added to the system for simulation research.Aiming at the problem that the PMSM for underwater robots can not use a control method simply when working in the full speed range,the high frequency pulse voltage injection method and the sliding mode observer method are combined.For the fluctuation problem existing when the two methods are switched,the compound weighted control strategy is studied specifically,and the control effect of the strategy is verified through simulation experiments.