Research On IPMSM Multi-parameter Online Identification Method Based On Harmonic Injection

Permanent magnet synchronous motor has been widely used in new energy power,aerospace,transportation and household appliances in recent years due to its high efficiency and high power density.In the actual operation of the motor,the parameters change with the change of the operating environment and conditions,such as the stator resistance increases with the increase of temperature,the inductance and permanent magnet flux linkage will be affected by the saturation of the magnetic circuit and the cross coupling effect,and the variation of these parameters will have a serious impact on the control and operation performance of the motor system,so it is necessary to identify the real-time parameters of the motor.Analyzed the research production of motor parameter identification both domestic and overseas,and the advantages and disadvantages of offline and online identification methods are analyzed and compared,the research goal of online identification of motor parameters is established.Firstly,The influence of magnetic circuit saturation and cross coupling effect on motor parameters is not considered in the traditional motor model,and its parameters are often regarded as constants,so the traditional motor mathematical model is not accurate.Therefore,this paper establishes an improved motor mathematical model through in-depth analysis of the traditional motor mathematical model and the factors affecting the change of motor parameters.With Ansoft Maxwell finite element analysis software,the motor body model was designed to obtain the variation curve of q-and d-axis inductance,and an improved variable inductance parameter motor model was built on MATLAB/Simulink simulation platform.Through simulation,it is proved that the improved variable inductance parameter motor model has the ability to simulate the operation of the physical motor.Secondly,for the multi-parameter simultaneous identification of permanent magnet synchronous motor,the identification model is usually in the under-rank state,resulting in the identification result is not unique.By studying the existing motor parameter identification method based on harmonic injection,it is known that the method can increase the number of equations in the identification model.Therefore,based on the improved motor mathematical model considering magnetic circuit saturation and cross-coupling effect,this paper uses the harmonic current injection method to establish a full-rank identification model to realize the online simultaneous identification of multiple inductors and permanent magnet flux linkages.Finally,by building a complete simulation model of parameter identification system,the effectiveness and accuracy of the proposed identification method are verified under different operating conditions of the motor.The simulation results show that the harmonic current injected into the motor has good stability under no-load and load conditions,as well as different rotational speeds and torque conditions.The identification results of multiple inductances and permanent magnet flux linkage parameters are more accurate than those obtained by the finite element method.In addition,the proposed multi-parameter identification method has the advantages of simple algorithm and fast identification speed,which is suitable for online identification.