| Permanent magnet synchronous motor(PMSM)has the advantages of small size,high power density and high efficiency,so it is widely used in wind power generation and electric vehicles.Its control system often uses speed sensors to obtain information such as motor speed and position,but the installation of speed sensors will increase the size of the motor and increase manufacturing costs,and will also limit the application of the motor.Therefore,the speed sensorless control method of PMSM is studied in this paper.During the operation of the motor,the parameters change due to temperature rise and magnetic saturation,which affects the control accuracy of deadbeat and speed sensorless.Therefore,it is of great significance to study the speed sensorless control method for on-line identification of motor parameters.First,the structure of the PMSM is analyzed,and mathematical models in three common coordinate systems are established.At the same time,the principles of space vector pulse width modulation(SVPWM)technology and deadbeat current predictive control(DPCC)are described in detail,and the correctness and reliability of PMSM deadbeat control system are verified by simulation.Secondly,the basic principle of disturbance observer(DOB)is studied,an improved DOB is designed to estimate the back electromotive force of the motor,and the estimated speed and rotor angle of the motor are obtained by phase-locked loop.The speed sensorless control of PMSM based on DOB is realized.In order to solve the problem that the accuracy of the traditional rotor angle compensation method is affected by the speed,a new rotor angle compensation method is proposed by constructing a low-pass filter with the same cut-off frequency as the DOB to compensate the estimated rotor angle.The proposed method eliminates the influence of inaccurate speed estimation on the compensation angle,so as to obtain more accurate rotor angle estimation accuracy.In view of the disadvantage that the accuracy of DPCC is affected by flux,the amplitude and angle of the estimated back electromotive force obtained by DOB are compensated,and then calculated in deadbeat control.The influence of motor flux on the control system in deadbeat control is eliminated and the robustness of the control system is improved.Simulation and experimental results verify the effectiveness of the method.Thirdly,the influence of motor inductance parameter mismatch on deadbeat control with speed sensor is analyzed in detail,and the inductance parameter identification of PMSM based on model reference adaptive is studied.The influence of inductance parameter mismatch on deadbeat control is solved,and the effectiveness of the method is verified by simulation.Finally,the influence of motor inductance parameter mismatch on DOB and deadbeat control without speed sensor is deeply analyzed,and an inductance identification method based on pulsed high-frequency voltage injection(HFPVI)method is proposed.The HFPVI method and its current response are mathematically deduced in detail.By demodulating and filtering the d axis high frequency response current,the on-line identification of motor inductance parameters and the real-time updating of controller parameters are realized,effectively improved the stability and robustness of DOB and deadbeat control.Simulation and experimental results verify the effectiveness of the identification method. |
