| High speed permanent magnet synchronous motor(HSPMSM)has the advantages of high power density,fast response and high efficiency.It is widely used in machine tools,air compressor,vacuum pump,distributed generation,energy storage system and friction welding.Due to high frequency,the finite switching frequency of converter leads to the lower carrier ratio,and the fewer turns of armature windings and lower permeability of permanent magnets leads to the smaller inductance value.As a result,much high frequency time-harmonics appear in armature current,which would increase the motor frequency electromagnetic loss,increase the temperature of the motor heating,and reduce motor the efficiency and reliability.In addition,the faster rotation speed,the stronger rotor whirl,the closer these two frequencies and the greater vibration and noise.What’s worse,severe structure failure happens in the motor.In this paper,the permanent magnet synchronous motor for the spindle is studied,and analysis method of electromagnetic and mechanical properties will be established in the HSPMSM.Not only mechanism,calculation method and effect of the magnetic field,magnetic consumption,magnetic force and vibration generating are revealed,but also the research on power harmonic analysis,electromagnetic loss calculation,slotted magnetic field resolution and the electromechanical coupling motion prediction are carryied out.Firstly,ideal and nonideal output voltage analysis model of sinusoidal and non sinusoidal PWM inverter were established separately,and Fourier series expression of phase voltage and phase current of the HSPMSM were derived from mathematical model of the HSPMSM for achieving their spectrum distribution.The model is applicable to the complicated situation with sampling rules,dead time effect,delay effect,pulse width limit and non integer carrier,and its accuracy was verified by simulation and experimention.The model was applied to the optimization of the control strategy of the PWM inverter circuit,and the harmonic injection PWM modulation mode was studied and verified.Secondly,The electromagnetic loss analysis model of HSPMSM was established and high frequency harmonics of the PWM power supply was considered.The analysis model include wire winding loss model,sheet core loss model and bulk eddy current loss model,and accurate calculation formulas of electromagnetic loss were derived respectively.Based on the model and formula of high frequency electromagnetic loss of the HSPMSM,electromagnetic losses were calculated with different excitation sources,such as pulse width modulation voltage source,pulse width modulation current source,sinusoidal voltage source and sinusoidal current source in the HSPMSM motor and control system.the influence laws of system parameters on electromagnetic losses of the HSPMSM were furtherly revealed,and calculation results were verified by the separation experiment of the electromagnetic loss and the mechanical loss.Thirdly,With algebraic and collection for the current carrying coil,armature windings and permanent magnets were simulated,and analytical expressions of armature magnetic field and permanent magnet excitation magnetic field were easily derived in the slotless HSPMSM.When slot effect of HSPMSM was described by air gap permeance and dealt with mirror image and conformal conformal transformation,the equivalent slotless air-gap domain ine the T plane would be obtained from slotted air-gap domain in the S plane through mapping of the Z plane and the W plane,and get air-gap permeance expression of the slotted HSPMSM was eventually achieved.With multiplication of slotless HSPMSM magnetic field and air-gap permeance of the slotted HSPMSM,the magnetic field of the slotted HSPMSM was analytically solved.Then main performance parameters of armature inductance,back EMF,cogging torque and electromagnetic force of the HSPMSM were analytically calculated and verified by the finite element analysis results.Finally,high speed motor rotor system was equivalent to the combination of elastic shaft,lumped mass,and spring.when the kinetic energy and the potential energy of equivalent elements were substituted into the Lagrange equation,free motion model of elements and electromechanical coupling system were established,which laid the theoretical foundation for exploring critical speed and whirl mode of the high speed rotor system and the sensitivity of high speed rotor system parameters on critical speed.By using mass eccentricity excitation source and step excitation excitation source for simulation forced motion of high speed rotor system characteristics,the forced motion equation of centrifugal force and driving force of rotor system were derived,and the behavior of steady and transient responses of the rotor system was predicted,which was conducive to the optimization design of high speed motor rotor system. |
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