What algorithm is used in the Parameter Estimation Blocks in the Motor Control Blockset?

In the Motor Control Blockset, there are various blocks such as Rs Estimator, Lq Estimator and so on to estimate motor parameters for a PMSM/IM. It is clearly stated that the Rs Estimator works on Ohm's Law but for Ld and Lq, it is unclear from the generated code what algorithm or formula is used. Frequency Sweep Estimation seems generic to me.

The actual source code is inaccessible as p-code but I understand the C code generated from the embedded coder is legal to use and modify as per use my target embedded platform. For this I wish to understand the basis for the code in terms of equations and fundamental laws. I am new to motor control, and would be happy to be pointed in the direction of resources like scientific literature or documentation to understand the technique MATLAB has used. I am not requesting the source code itself.

Thank you.

Answer 1

[Pratik]

Hi Sneha,

As per my understanding, you want to know more about the technique MATLAB has used to estimate motor parameters for stator inductance "Ld" and "Lq".

From what can be inferred from the documentation, algorithm appears to be based on the principle of injecting a high-frequency voltage signal into the q-axis of the motor and then measuring the resulting current response to estimate (Lq) and similar method to estimate "Ld". The technique involves detecting the phase difference between the injected voltage and the resulting current waveform, which is directly related to the inductance.

Please refer to the documentation of "Ldestimator" and "Lqestimator" for more information:

https://www.mathworks.com/help/mcb/ref/ldestimator.html

https://www.mathworks.com/help/mcb/ref/lqestimator.html

I hope this helps.