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The Question of The Back Electromotive Force (BEMF) observer

11-01-2019
10:55 PM

261 Views

董培董

Contributor II

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Hello!!!

I have been reading the document<MC9S12ZVMMCLUG> recently, it's not particulayly clear about the AMCLIB_BemfObsrvDQ.I hope I can get your help, Thanks！！！

The BEMF observer fits the input voltages and currents to a mathematical model of the

motor. The model mirrors the behavior of the PMSM; see the following equation:

But,The mathematical model of the motor should be the following equation:

The red mark is different.The document explains it as follow:

But I still dont't know why,I hope to get a detailed explanation. Thank you very much!!!

2 Replies

11-15-2019
02:04 AM

111 Views

pachamatej

NXP Employee

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Hi,

The model introduced in the AppNote uses "extended back-EMF", which is different from the actual EMF. Please refer to the following picture. Full explanation would basically do the same as set of articles on IEEE (https://ieeexplore.ieee.org/search/searchresult.jsp?newsearch=true&queryText=extended%20back%20emf%2...)

I hope it helps,

Matej

11-15-2019
02:28 AM

111 Views

董培董

Contributor II

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Hi，

I will read the articles on IEEE, thank you very much