Research On Sensorless Control Of Permanent Magnet Synchronous Motor In Full Speed Range

The permanent magnet synchronous motor(PMSM)studied in this paper has the advantages of small size,large power density,wide speed range,and it is widely used in electric drives and servo systems.PMSM control requires accurate rotor position information,but traditional position sensors increase the size and cost of the motor and reduce the reliability of the system.Therefore,this paper studies PMSM sensorless control technology.In this paper,through the establishment of the mathematical model of PMSM,the sensorless control technology is studied in the full speed range.The main contents are as follows:(1)Construct a mathematical model of a permanent magnet synchronous motor,and study the pulse vibration high frequency voltage injection method to achieve the permanent magnet motor starting from zero speed to low speed.In this paper,the traditional pulsed high frequency voltage injection method is improved.The saturation characteristics of inductance are used to derive the high frequency current under the saturation of the straight axis flux linkage,thereby achieving the initial position of the motor.At the same time,the traditional pulsed high frequency voltage injection method uses a large number of filters,which causes the system response delay and reduces the dynamic performance of the motor at low speed.This paper improves the use of filters when extracting current signals,and the motor speed and position have a better estimation effect.The results of simulation show that the scheme can improve the robustness of the system and realize the rapid response of the motor.(2)The motor uses a sliding mode observer to estimate the rotor position at medium and high speeds.The traditional sliding mode observer has the problem of chattering,and the low pass filter will bring the counter electromotive force observation amplitude reduction and bring the observation phase delay,in this paper,the sliding mode control rate is improved to effectively improve the estimation accuracy of rotor position and speed.An adaptive terminal sliding mode control method based on disturbance observer is designed in the velocity loop.The motor uses weighted switching from the high frequency pulse injection method to the sliding mode observer method,and the rotation speed in the switching interval is obtained by weighting the respective speed estimates of the two methods.Through simulation can acquire results to verify the sliding mode observer and motor speed loop control method proposed in this paper has more accurate estimation results,the position error becomes smaller,and the motor operation is more stable than traditional algorithms.(3)Experimental platform of PMSM control system using the DSP TMS320F28335 controller is established,and the specific software and hardware implementation methods are also proposed.The designed hardware platform includes a control board and a driver board,where the hardware platform control board includes DSP controller system module,data acquisition module,and circuit protection module;the driver board contains system power module,intelligent power management module(IPM)and circuit around the system.In the design of software,the development environment of DSP controller and the steps of corresponding software development are mainly explained.The experimental results show that this scheme can achieve better sensorless motor control.