Is the abc_to_dq0 Transformation correctly defined in SimPowerSystems?

In the abc_to_dq0 Transformation block, the direct axis value is obtained from a scaled combination of the sin values of the phase variable. And q from a scaled combination of cos values.

In other definitions (Wikipedia, Mohan), the d axis is obtained from a scaled combination of cosines and the q from a scaled combination of -sines. Also Park's definition uses this.

Is this Matlab definition a mistake, which references itself as the Park transformation, but it's not? Could someone please confirm this or show me where I could find more information on this if it is correct.

Thanks in advance.

Answer 1

[Joel Van Sickel]

It is correct, howerver, there are mutliple standards for reference frames which can cause confusion. (such as a 90 degree offset for some)

[Donal Murray]

Thank you, I discovered this myself too.

I haven't used Matlab in a few years now, I presume the used abc to dq0 transforms and back hasn't changed since 2012?

[Joel Van Sickel]

Actually, we've started giving options to change the assumptions to support different standards.

The current block allows it to be poewr invariant and choose the axis alignment: https://www.mathworks.com/help/physmod/sps/ref/parktransform.html

Previously, this has caused issues for a number of people since the assumptions were not clear or consistent in our products, so we are working to address that.