Design And Implementation Of Sensorless Control System For PMSM Based On High Frequency Signal Injection

Permanent magnet synchronous motor(PMSM)plays an important role in the industrial field due to its high efficiency,small size and simple structure.In the control system of PMSM,it is generally necessary to know the position of the rotor.However,it will increase the cost of the motor to install the mechanical position sensor,and the application of the motor will be limited especially in such cases as high temperature and heavy humidity,etc.To solve these problems,the sensorless technology of PMSM has been widely concerned.The author in this thesis regarded the interior PMSM as the research object.The highfrequency pulse voltage injection control algorithm was analyzed and an improved algorithm was proposed to track the rotor position at low and zero speed.In this thesis,the model of PMSM is established,the principle of high-frequency pulsevoltage injection method is expounded.The author adopted the saturation salient effect of the motor,compensated the estimated angle,and realized the detection of initial position for the rotor.In addition,the author provided the parameters design of high frequency pulse voltage injection method,which include the design of the filter,the selection of the position tracking observer and the selection of frequency and amplitude of the high frequency injection signal.The main task in this thesis is to study the racking effect of high frequency pulse voltage injection method on rotational speed in different carrier ratios.It can be concluded that increasing carrier ratio can improve the dynamic performance and stability on the control system in a certain range.The high frequency injection algorithm is applied when the motor parameters change,which proves that the algorithm does not depend on the motor parameters and has strong robustness.At the same time,according to the influence of the band-pass filter on the control system in the traditional algorithm,the author in this thesis proposed a new improved algorithm,applied the analysis method of the Fast Fourier Transform(FFT)to the detected current signal,which could directly extract the information containing the rotor position error and reduce the use of band-pass filter and low-pass filter.In the context of MATLAB/Simulink,the author did a simulation comparison experiment on the traditional algorithm and the improved algorithm,which proved that the improved algorithm has better control performance.Finally,the improved high-frequency pulsating voltage injection method proposed in this thesis was tested on the PMSM physical experiment platform based on TMS320F28335.The results verified the accuracy of the content in this thesis,and the improved algorithm made the sensorless control system have good steady-state performance and dynamic performance.