Patent ID: 8564972

Claim:
An inverter control device comprising: a first rectifier rectifying AC input; a first switching element and a second switching element disposed between outputs of the first rectifier, constituting a first switching circuit, series-connected; a third switching element and a fourth switching element disposed between outputs of the first rectifier, constituting a second switching circuit, series-connected; a power conversion transformer, one end of a primary winding of which is connected to a junction between the first switching element and the second switching element and another end of the primary winding of which is connected to a junction between the third switching element and the fourth switching element; a second rectifier rectifying output from the power conversion transformer; an output power detecting part detecting one of an output current and output voltage from the second rectifier; an output power setting part for preliminarily setting one of an output current and output voltage; an error amplification part determining an error between a signal from the output power detecting part and a signal from the output power setting part, and outputting the error; and an inverter control part outputting a signal controlling operation of the first switching circuit and the second switching circuit according to a signal from the error amplification part, wherein the inverter control part includes: a first switching circuit control part outputting a drive signal for alternately bringing the first switching element and the second switching element constituting the first switching circuit into conduction; and a second switching circuit control part outputting a drive signal for alternately bringing the third switching element and the fourth switching element constituting the second switching circuit into conduction, wherein the second switching circuit control part includes: a pulse-width modulating part generating a conduction width that is time during which the third switching element and the fourth switching element are kept in conduction, according to a signal from the error amplification part, and outputting the conduction width; a phase control part generating conduction time during which the third switching element and the fourth switching element are kept in conduction, the conduction time being a phase difference in relation to conduction time of the first switching element and the second switching element, according to a signal from the error amplification part, and outputting the phase difference; and a signal changing part accepting a signal from the pulse-width modulating part and a signal from the phase control part, and outputting one of a signal from the pulse-width modulating part and a signal from the phase control part according to a signal from the error amplification part.