Patent ID: 8743569

Claim:
A power supply device comprising: a rectifier circuit rectifying a first alternate current voltage; an active filter provided at a stage subsequent to said rectifier circuit; a smoothing circuit smoothing a voltage output from said active filter to generate a direct current voltage; an inverter converting said direct current voltage to a second alternate current voltage, said active filter including a reactor having one terminal receiving a voltage output from said rectifier circuit, a diode having an anode connected to said reactor at the other terminal, and a cathode connected to said smoothing circuit, and a switching element connected between the other terminal of said reactor and a line of a reference voltage; and a microcomputer operative to detect a current input to said active filter, a voltage input to said active filter, and said voltage output from said active filter and generate a target voltage based on said voltage input to said active filter, and control said switching element to turn on/off said switching element to match said current input to said active filter and said voltage input to said active filter in phase with each other and also match said voltage output from said active filter to said target voltage, wherein: if said current input to said active filter exceeds a first threshold current, said microcomputer stops controlling said switching element to turn on/off said switching element, and if said current input to said active filter exceeds a second threshold current larger than said first threshold current, said microcomputer further stops controlling said inverter; and if said voltage output from said active filter exceeds a first threshold voltage, said microcomputer stops controlling said switching element to turn on/off said switching element, and if said voltage output from said active filter exceeds a second threshold voltage larger than said first threshold voltage, said microcomputer further stops controlling said inverter.