Hello,
Looking over the STSpin implementation of the Clarke Park transforms and SVM has raised some questions about the derivation of the transform.
Typically the the Clarke Transform takes the form of:
𝐼𝛼=𝐼𝑎
𝐼𝛽=1√3(𝐼𝑎+2𝐼𝑏
STSpin's implementation effectively rotates the Beta component by 180 degrees with a sign flip:
𝐼𝛼=𝐼𝑎
𝐼𝛽= -1√3(𝐼𝑎+2𝐼𝑏)
Next, the Park transform usually takes the form of:
𝐼𝑑=𝐼𝛼∗cos(𝜃)+ 𝐼𝛽∗sin(𝜃)
𝐼𝑞=𝐼𝛽∗cos(𝜃)−𝐼𝛼∗sin(𝜃)
Where as STSpin seems to rotate each dq component by 90 degrees by using the opposite trigonometric functions on the alpha/beta vectors
𝐼𝑑=𝐼𝛼∗sin(𝜃) + 𝐼𝛽∗cos(𝜃)
𝐼𝑞=𝐼𝛼∗cos(𝜃)−𝐼𝛽∗sin(𝜃)
Considering Beta is negative in the STSpin Clarke, it seems that Iq is actually equal to Id in the "correct" Park transform. Does anyone have an explanation for this?
Separately, the SVM seems to be empirically 120 degrees out of phase with an SVM implementation from this paper. Is this to compensate for the different reference frame in the STM transformations?
