Patent ID: 8570781

Claim:
A power conditioner comprising: a first switch circuit including a pair of series-connected switches and a first capacitor connected in parallel with the first switch circuit; a second switch circuit including a pair of series-connected switches and a second capacitor connected in parallel with the second switch circuit; and a controller processor for alternately turning on and off the pair of series-connected switches of the first switch circuit at a predetermined chopping frequency and for alternately turning on and off the pair of series-connected switches of the second switch circuit at a pulse width modulation (PWM) frequency higher than the predetermined chopping frequency, the controller processor forming a pulse voltage series that changes in a sinusoidal manner in a first series-connected portion of the pair of switches of the first switch circuit, forming a difference voltage according to a difference between the pulse voltage series and a sinusoidal voltage in a second series-connected portion of the pair of switches of the second switch circuit, and controlling on/off duty cycles of the switches of the second switch circuit to obtain the sinusoidal voltage that changes between positive and negative values, wherein the controller processor calculates an offset between a timing of switching between positive and negative voltage differences between the pulse voltage series and the sinusoidal voltage and a timing of switching between the on/off duty cycles of the switches of the second switch circuit, and the controller processor controls the on/off duty cycles of the switches of the second switch circuit according to the calculated offset.