Performance Improvement Of Position Sensorless Control Of Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection Method

The position sensorless control algorithm of permanent magnet synchronous motor(PMSM)has been widely studied,since the removal of position sensor and the corresponding mechanical connecting device can shorten the axial length and improve the robustness of the motor system,it can also improve the cost,power density and environmental adaptability of the system.At present,the research of PMSM sensorless control algorithm based on back electromotive force(EMF)method has been relatively mature,but this method is not suitable in low speed zone,so it is of grerat significance to investigate the position sensorless control algorithm of PMSM in low speed zone.In this thesis,an interior PMSM(IPMSM)is used to research square-wave voltage injection(SWVI)based position sensorless control algorithm.The main contens and innovations of this thesis are as follows:1.The mathematical model of PMSM based on space complex vector is established,the principle of PMSM field-oriented control is briefly explained,and the linear modulation area of using space vector pulse width modulation(SVPWM)is pointed out.2.The discrete-time domain mathematical model of PMSM considering the output voltage clamping effect and sampling timing of the PWM inverter is established.Based on the principle of zero-pole cancellation,the discrete-time current-regulator which can improve the dynamic decoupling capability and robustness of the current loop is designed by direct discretization method.3.Briefly described the principle of SWVI position sensorless control algorithm,the consistency of the signal processing in synchronous reference frame and stationary reference frame are verified.The parameter adjustment methods of the phase-locked loop observer and the Luenberger observer are analyzed and verified by experiments.4.The mathematical model of SWVI position sensorless control algorithm considering cross-saturation inductance is established,and the influence of crosssaturation angle on rotor position estimation is pointed out,an offline measurement and online compensation scheme of cross-saturation angle based on SWVI is proposed,the effectiveness of the scheme is verified by experiments.5.The principle of the recursive least square method with forgetting factor and the state observer method for inertia identification is briefly described.The advantages and disadvantages of the two algorithms are compared through simulation results,and the validity of the state observer method for inertia identification is verified by experiments.