Pump system and method for operating the same

Abstract

Provided is a pump system. The pump system includes an AC (alternating current) electric motor, a converter, a smoothing unit, an inverter, a volt/hertz pulse width-modulation controller, and a main controller. The AC electric motor operates a pump which is a load. The converter receives AC power and converts the AC power into DC (direct current) power. The smoothing unit smoothes a DC voltage converted by the converter. The inverter converts the DC voltage output from the smoothing unit into an AC voltage. The volt/hertz pulse width-modulation controller applies switching voltage to a semiconductor switching device of the inverter. The main controller changes an operating frequency according to a load detected when the Ac electric motor is in operation and puts the AC electric motor to a sleep mode after determining a load operation status.

Dependencies are inferred from the claim text.