| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve efficiency by reducing the loss of a power converting device that supplies AC electric power to a load or to a system, by performing AC conversion, after stepping up the photovoltaic voltage. <P>SOLUTION: An inverter unit 1 comprises single-phase inverters 1B-INV, 2B-INV, 3B-INV, into which electric power from DC power supplies V<SB>1B</SB>, V<SB>2B</SB>, V<SB>3B</SB>having the voltage ratio of 1:3:9 is inputted, respectively, and the AC sides are connected in series. An output voltage is controlled in gradation according to the total sum of each generated voltage. Also, the DC power supply V<SB>3B</SB>of the maximum voltage is formed, by stepping up the photovoltaic voltage V<SB>O</SB>with a chopper circuit 3, and the loss related to the stepping-up is reduced, by stopping the step-up operation of the chopper circuit 3, when the V<SB>O</SB>exceeds a prescribed voltage V<SB>m1</SB>(195 V). <P>COPYRIGHT: (C)2006,JPO&NCIPI |
