I was North. I had no idea what partner was doubling on nor why she couldn't find a 1♠ overcall. It can't be takeout as the opps have bid three suits, but what can partner have to penalise when she couldn't do anything on the first two rounds? Is opener 1444 and they have landed in a 4-2 fit and she is sitting with a diamond stack?
2♦X makes 10 tricks for -580 which is a top for us. The other two pairs are in 3NT+1 and 5♦+1 for 620 and 630. I have never seen the strategy of doubling the opponent's making partscore with overtricks in order to seduce them out of a higher scoring game before.
After questioning what partner was thinking it turns out she was applying the principle of not letting the opponents play in a two level contract and was trying to do a TOX, playing me for some HCP, although the standard when making a TOX is that there are at least two possible strains to play in.