Position Sensorless Control And Model Predictive Current Control Of Permanent Magnet Synchronous Motor

In this paper,permanent magnet synchronous motor(PMSM)is taken as the re-search object.The sensorless control system based on non-singular fast terminal slid-ing mode observer and the novel three-vector model predictive current control system are studied respectively.Aiming at the chattering phenomenon of conventional sliding mode observer in sensorless control system of PMSM,a non-singular fast terminal sliding mode observer algorithm is proposed.And a novel three-vector model predic-tive current control algorithm is proposed to solve the problem of large ripples of motor phase current in single-vector and two-vector systems.(1)The mathematical model of PMSM in three-phase stationary coordinate sys-tem and two-phase rotating coordinate system is established.The matrixs for Clarke transformation and Park transformation,and their inverse matrixs(anti-Clarke trans-formation and anti-Park transformation)are deduced.The principle of output space voltage vector of three-phase voltage source inverters is briefly described.(2)The sensorless control of PMSM based on non-singular fast terminal sliding mode observer is studied.The chattering phenomenon of sensorless control system of PMSM based on traditional sliding mode observer is pointed out.And the reason of chattering in the system is analyzed.In order to estimate the position and speed of motor rotor accurately,the chattering of control system must be suppressed.A non-singular fast terminal sliding mode observer based on d-q axis coordinate system is established.The observer takes into account the advantages of linear sliding mode and non-singular terminal sliding mode.The designed sliding mode control law meets the stability requirements of the system.Thereafter,nonlinear tracking differentiator can generate the smooth d-q axis back EMF.And the speed and position of motor ro-tor are modulated from d-q axis back EMF with phase-locked loop.The simulation results of MATLAB/Simulink show that the proposed method can effectively suppress the chattering phenomenon.(3)The novel three-vector model predictive current control of PMSM is studied.A single-vector,two-vectors and a novel three-vector model predictive current control system are designed respectively.Aiming at the problem that the direction and ampli-tude of the output voltage vector of the former two are limited and the motor current ripples is large,a novel three-vector model predictive current control strategy is pro-posed.The first optimal voltage vector is selected through six times online current predictions.When selecting the second optimal voltage vector,it only needed to judge the sector number of the error vector between the predictive current value produced by the first optimal voltage vector and the reference current value,and its selection principle is to reduce the error.Finally,the zero vector is introduced to adjust the am-plitude of the output voltage vector.So the output voltage vector direction and ampli-tude could be adjusted.The basic voltage vectors actuation durations were calculated by the current deadbeat control principle of d and q axis.MATLAB/Simulink simula-tion experiments show that the novel three-vector model predictive current control strategy can effectively reduce the phase current ripple of the motor.(4)The experimental verification of the two-vector model predictive current control system and the novel three-vector model predictive current control system is carried out.The experimental waveforms show the effectiveness and accuracy of the proposed method.