Why is the phrase "Hashem yimloch l'olam va'ed" repeated in the paragraph after Tehillim 30?^* I've heard it has everything to do with the writings of the Arizal, but I'm not sure.

This question is unique to Nusach Sfard and the Sephardi nusachot, in somewhat of a follow-up to my previous question regarding the phrase's repetition in "Az Yashir".

^{* "Mizmor shir chanukat habayit l'David..." You can see what I'm talking about here.}