Permanent Magnet Electric Spindle Motor Flux-weakening Rotor Parameter Calculation And Performance Analysis

With the development of modern motor control technology, permanent magnetsynchronous motor with the advantages of high efficiency and high power density, in manyapplications gradually replaced the traditional induction motors. Compared with the inductionmotor, the permanent magnet excitation rotor in permanent magnet synchronous motor caneffectively solve the heating problem. But at the same time, the immobility of the magneticcircuit restricts the speed range of the motor. In the field of machining, the electric spindle wasrequired a certain speed range, which limit the application of permanent magnet synchronousmotor. How to solve the problem of flux weakening to improve the motor speed range hasbecome a research Emphasis.This paper first introduces the domestic and foreign development status of electric spindlemotor. For the problem of flux weakening in permanent magnet synchronous motor whichapplied to electric spindle, introduce the flux weakening research status in the domestic andabroad.Then in view of the permanent magnet synchronous electric spindle motor almost usesvector control, combined with the flux linkage vector equation and voltage vector equation ofthe permanent magnet synchronous motor from the angle of motor control, the paper analysethe effect of quadrature axis and direct axis inductance parameters on flux weakeningperformance. After that using Ansoft finite element analysis software to design and calculatedifferent magnetic circuit structure rotor model, observed the no-load gap flux densitywaveforms and the no-load back electromotive force waveforms of the permanent magnetsynchronous motor. In consideration of the d-q axis coupling effect, the calculation ofquadrature axis and direct axis inductance parameters and the regularity analysis with thechanges of d-q axis current, and the influence of different pole-arc coefficient on inductanceparameter were concluded.Finally, the vector control system of permanent magnet synchronous motor was introduced.The maximum torque/current control strategy and advance angle flux-weakening controlstrategy were used to build a permanent magnet synchronous motor simulation control systemin Matlab/Simulink platform. Combining with the design parameters of the motor, theperformance of the flux weakening control system was confirmed.