Author Topic: What's the difference between isotropic and anisotropic motors?  (Read 1652 times)

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Offline bonzerTopic starter

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Hello everyone, What's the difference between isotropic and anaisotropic motors? For example in case of IPM/SPM motors? Can someone help me please to understand this.
For example in magnets there's a preferential direction for the axis of polarization in anisotropic magnets. Here I've just seen sum images of the structures that are different but I really don't get why some are called anisotropic and others isotropic.
 

Offline bonzerTopic starter

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Re: What's the difference between isotropic and anisotropic motors?
« Reply #1 on: November 27, 2019, 09:27:10 am »
What I've seen so far is that the shape of the rotor changes so in isotropic case it's not symmetrical and because of that it is easier to be moved by magnetic fields applied
 

Offline bonzerTopic starter

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Re: What's the difference between isotropic and anisotropic motors?
« Reply #2 on: November 27, 2019, 07:05:27 pm »
SOLVED!

It's all about the rotor structure. In SPM motors it's isotropic so there's no priority for any direction of the fields generated by surface pm while in IPM type they put pm inside the rotor in such a way to make it possible so in the end it gives additional torque cause by that reluctance effect. See the image for the comparison.

 

Offline max_torque

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Re: What's the difference between isotropic and anisotropic motors?
« Reply #3 on: November 28, 2019, 12:22:25 pm »
The other word to seach around is " Magnetic saliency"

For an SPM with a uniform rotor core, peak torque occurs when the stator field is precisely aligned with the quadrature (q) axis, ie 90 deg to the direct (d) axis.

For an IPM, with high saliency, the position of peak torque is directly dependant upon that saliency, and the position of peak torque is skewed towards to d axis. How far it is skewed depends upon both fixed geometrical effects, and dynamics ones such as reluctance and saturation.

 
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