How to compensate time delay of a sine wave?

I am currently working on sensorless control algorithm with a FOC and a full order SMO. The algorithm is discretized and works fine.

Now i should add an input and an output delay for the current sampling and the update of the SPVM. The figure below shows a minimal working example of the problem, where a sine wave is generated for the current, the sample order hold simulates my ADC and then I modeled a input and output delay with unit delay blocks.

Does anyone know an approach to compensate these delays?

Answer 1

[Mathieu NOE]

hello

if you know your delays and the rotationnal speed of your motor you can compute a "compensation" angle to be added to the measured angle , so it's like you have no delays in your FOC loop.

[Martin Maier]

Hello Mathieu NOE,

yes, I know my delays. In this case, you would suggest to compensate the delays only by shifting the angle.

My current solution is a linear prediction filter for the measured current that compensates the delays. But there I have a problem with the current being amplified at high speeds.

[Mathieu NOE]

Hello Martin

yes , I was suggesting our method for FOC for brushless motor (sine command)

the delays are measured and we add a compensating angle depending of the measured speed.

there may be other solutions, but that one works for us

all the best

[Martin Maier]

Hello Mathie Neo,

Thank you for your help and the fast resposne.

All the bests.

[Mathieu NOE]

as always, my pleasure !