I mean that you should do something that allows you to progress fast because you haven't been training seriously lately. 5/3/1 is a slow progression, you could use that but adjust your maxes any time you set a big PR.
There isn't supposed to be a power phase for powerlifting, as strange as that sounds. The point of a power phase is to take the strength that you developed in the previous phase and use that to develop speed and acceleration. It works for throwing sports and stuff like that, but in powerlifting it doesn't matter how fast you move the weight as long as you move it. What you need is a peaking phase. You should be doing a lot of work with 80%+, up to 90-95% in the last few weeks before the meet. You can do some singles around 90% too, but lots of people never do singles in training. Worry about that when you get to it, focus on getting stronger first.
When is your meet?