Research On High-precision Position Sensorless Control Strategy Based On Heteropolar Double Air Gap Correctio

In recent years,the research of position sensorless control technology continues to boom,its cost,space,weight,reliability,integration,power density,working condition adaptability has greater advantages compared to mechanical position sensor,improve the control performance of position sensorless has been the focus of attention of researchers.This paper provides an in-depth study of high-precision position sensorless control.Firstly,the mathematical models of the interior permanent magnet synchronous machines(IPMSM)in different coordinate systems are established,and simulation models are built to verify the control parameter design and the control performance of the dual closed-loop vector control system,which lays the foundation for the subsequent research on the position sensorless control technology.Secondly,the sliding mode observer(SMO)method in the medium-and high-speed position sensorless control algorithm is studied in depth,and the causes of the high-frequency AC component generated by the position observation error are analyzed.Starting from the construction principle of the SMO,the sliding mode control function,slope coefficient,sliding mode gain and rotor position solution method are optimized respectively,and the optimization effect is verified on the simulation platform.Again,a theoretical study is conducted to address the problem of DC bias in the position observation error caused by changes in parameters during motor operation.After the derivation and analysis,the expression of the quantified relationship between the position observation error and the perturbation of motor parameters is derived,and the influencing factors were finally focused on the q-axis inductance and stator resistance parameter variations according to the degree of parameter variations.With the aid of the position sensorless control system of the SMO,the simulation experiments are carried out by selecting a suitable range of parameter variations and comparing the experimental results of different parameter variations with the calibration parameters to prove the correctness of the proposed conjecture.Then,a dual air gap correction strategy is proposed on the basis of full speed domain position sensorless control by combining the special pole logarithm design of the heteropolar dual-gap dual-pole composite machines(DDCMs)of the used experimental object.Finally,the feasibility of the above algorithm is verified on the experimental platform of the DDCMs.