| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve efficiency by reducing the loss of a power conversion apparatus that supplies AC electric power to a load or a system by performing AC conversion after stepping up a 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 input, respectively. The AC sides of the unit 1 are connected in series, and an output voltage 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. The loss related to the stepping-up is reduced by stopping the stepping-up operation of the chopper circuit 3 when the V<SB>O</SB>exceeds a prescribed voltage V<SB>m1</SB>(195 V) and by bypassing a reactor 3b and a diode 3c inside the chopper circuit 3 with a relay 7a connected in parallel. Furthermore, conduction loss of the components inside the chopper circuit 3 is eliminated. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
