The ornamental design for a powerinverter, as shown and described.
FIG. 1 is a front perspective view of a power inverter showing my new invention;
FIG. 2 is a front view of the power inverter as shown in FIG. 1;
FIG. 3 is a rear view of the power inverter as shown in FIG. 1;
FIG. 4 is a left side view of the power inverter as shown in FIG. 1;
FIG. 5 is a right side view of the power inverter as shown in FIG. 1;
FIG. 6 is a top view of the power inverter as shown in FIG. 1; and,
FIG. 7 is a bottom view of the power inverter as shown in FIG. 1.
The broken lines immediately adjacent to the full line showing of the claimed design represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.