Research On Control Technology Of Six-Phase Permanent Magnet Synchronous Motor Based On Position Sensorless

Modern control theory has achieved leapfrogging development compared with traditional control.The field of motor control is developing towards high voltage,high current and higher reliability.In the face of high demanding applications that electric vehicles,civil aviation power system and military vessels requiring higher reliability,higher power level,higher speed regulation performance,the traditional three-phase motor can not meet demanding requirements due to its own limitation.However,multiphase motor thanks to its low power,small torque ripple and fault-tolerant performance,can be favored by the motor control system performance requirement of the field.Considering the increase of hardware cost caused by the installation of position sensor,the impact of environment and the fault of position sensor,it studies the vector control system without position sensor of asymmetric six-phase permanent magnet synchronous motor(PMSM).Firstly,the transformation matrix in the different rotating synchronous coordinate system is deduced through the double d-q transformation and the space voltage vector decoupling transformation respectively,so as to realize the decoupling of the physical model of the motor.On the basis of space decoupling vector transformation,the realization algorithm of SVPWM modulation technology with the fourth-largest vector is given.Secondly,the position sensorless control system of six-phase PMSM is focused on.a sliding mode observer is designed to determine the current position of the rotor by calculation.By using Lyapunov function as the stability criterion,the suitable sliding mode increasing coefficient range is calculated to improve thestability and robustness of the system.Then,simulation experiments and comparative analysis are carried out for the no-load,sudden load,and low and high speed operation of the control system to verify the feasibility of the control system.Furthermore,The load torque observer with reduced dimension is designed.The observed value of load torque is equivalent to the turnover axis current to compensate for speed fluntuation by observing the instantaneous torque.the dynamic robustness and anti-load disturbance capability of the control system are improved.Finally,the sliding mode observer and reduced dimension load torque observer are designed and applied to the control system of six phase permanent magnet synchronous motor.The experimental platform of the six-phase permanent magnet synchronous motor drive system was built,and the effectiveness and feasibility of the strategy are verified by experiments on the designed control system.