The ornamental design for a powersupplyunit, as shown and described.
FIG. 1 is a top, front, and right side perspective view of a power supply unit showing our new design;
FIG. 2 is a bottom, front, and left side perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The even broken lines shown in the figures illustrate portions of the power supply unit that form no part of the claimed design. The uneven broken lines shown in the figures represent unclaimed boundaries.