Research On Sensorless Velocity Estimation Method Of Permanent Magnet Synchronous

Permanent magnet synchronous motors are widely used in the fields of new energy vehicles industry and agriculture and aerospace due to its simple structure,high efficiency,and easy control.The speed measurement system of permanent magnet synchronous motor generally uses traditional mechanical sensors,which increases the cost of the system and reduces the stability of the system.It is difficult to maintain and limit to use.To overcome the shortcomings of traditional sensors,the sensorless speed control technology came into being.The sensorless speed control strategy is based on the vector control of the permanent magnet synchronous motor.It estimates the motor speed by detecting the rotor voltage or current information of the stator windings to replace the traditional mechanical sensors.To this end,the vector control and space vector pulse width modulation of PMSM are modeled and simulated.Modeled and compared the sensorless speed control strategy in the high-speed section and the sensorless speed control strategy in the low-speed section.It is found that the existing control algorithms are suitable for speed sensorless control in a certain speed range.For example,the synovial observer control method and model reference adaptive method are suitable for the high-speed section,and the pulsed highfrequency voltage injection method is suitable for the low-speed section.Aiming at the problem that the sensorless speed control strategy cannot achieve accurate estimation in the full speed range,a composite control algorithm is proposed.After comparing and analyzing the sliding film observer control method and model reference adaptive method,it is found that the former has obvious advantage.Therefore,the middle and high speeds adopt the sliding film observer method,and the low speed(zero speed)uses the pulse vibration high frequency voltage injection method.The combination of the two achieves composite control.In the process of realizing the low-speed to medium-high-speed handover,by comparing and researching the two kinds of handover control of hysteresis handover and weighted handover,it is found that the weighted control is more stable.Therefore,the weighted control is used to switch the sliding film observer method and the pulsed highfrequency voltage injection method between medium and high speeds and low speeds to achieve a smooth transition of the composite control of the full speed section of the motor.The MATLAB/Simulink simulation model is constructed for all the above algorithms and control methods.Through simulation experiments,the rationality and feasibility of the proposed method are verified.Figure59;Table12;Reference 45.