| Surface-mounted Permanent Magnet Synchronous Motor(SPMSM)has advantages like high efficiency,higher power density,and large moment of inertia ratio,so it is widely applied.The high-performance SPMSM control system requires real-time and accurate acquisition of the rotor position information.However,the installation of the position sensor increases the manufacturing and maintenance costs of the system,and it not only makes the mechanical structure of the motor more complicated and larger,but reduces the system reliability.In order to reduce the use of position sensors,the thesis makes a research on sensorless control strategy of SPMSM in wide speed range.First,in the SPMSM zero-low-speed sensorless control based on pulsating high-frequency injection method,aiming at the problem of poor observation accuracy and instability caused by the inconspicuous "saturation salient" phenomenon generated by high-frequency injection voltage using electromagnetic saturation effect,an improved pulsed high-frequency voltage injection method is proposed.After injecting a high-frequency voltage sine wave on the d-axis,instead of rotating the q-axis in the traditional pulsating high-frequency injection method,extracting the αβ-axis high-frequency response current of SPMSM,the rotor position information obtained after processing is no longer dependent on the salient pole characteristic.Among them,the αβ axis high-frequency response current is extracted by a second-order generalized integrator with an adaptive change in the center frequency,compared with the bandpass filter in the traditional pulse high-frequency injection method,which can effectively resolve the problems of amplitude weakening and phase shift in the filtering process.Second,to solve the problems caused by the sudden load torque disturbance,which are the rotor position observation errors increase and the direction of the motor salient pole shifts brought by the electromagnetic saturation,an active disturbance rejection speed controller is proposed.The speed loop controller is designed with auto-disturbance rejection control technology,the tracking differentiator can solve the contradiction between overshoot and response speed in PID control.The extended state observer in the auto-disturbance rejection technology is employed to observe the load torque disturbance,and compensation is carried out in the state error feedback control law,which not only enhances the stability of the system and the ability to resist load disturbance,but also improves the observation accuracy of the rotor position in the position sensorless control.Then,in the SPMSM medium-high-speed sensorless control based on the sliding mode observer,concerning the problems of the decrease of the system reliability and observation accuracy of the rotor position due to the high-frequency chattering generated by the discontinuity of the sliding mode variable structure,two improvement strategies are proposed.The first is a position sensorless hybrid control strategy.On the basis of a single sliding mode position observer,a model reference adaptive position observer is added,and the switching control function is designed to utilize the higher steady-state accuracy of the model reference adaptive observer to solve the chattering problem caused by the sliding mode observer,while retaining fast dynamic response of the sliding mode observer at the same time.The second improvement strategy is to design a position observer based on a fast non-singular terminal sliding mode,introduce a sliding film attractor and combine the exponential approach rate to improve it.Besides solving the chattering problem,the state variables of the position observation can quickly converge to the actual rotor position in a limited time.Finally,based on the MATLAB/Simulink simulation platform and the hardware test platform built,the SPMSM wide-speed range sensorless control strategy proposed in this paper was simulated and experimentally analyzed,verifying its feasibility and effectiveness. |
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