| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized and light-weight system interconnection inverter which can supply an output current with low distortion by lowering the switching loss of the inverter and reducing capacitance of capacitor in the intermediate stage. SOLUTION: A voltage boost current monitor 17 is provided to set the capacitance of a capacitor 3 of the intermediate stage to several hundreds of μF or less and a monitor for the output current of a voltage boost converter 2. During a period, where an absolute value of a system voltage VAC is smaller than an input voltage Vin, voltage is increased by controlling the high-frequency switching of the voltage boost switching element 2c, while with the voltage boosting current monitor 17 is being monitored to provide an output current of the squared sine wave of the voltage boosting converter 2. Moreover, the inverter 4 changes polarity. During other periods, the voltage boost operation of the voltage boost converter is stopped, and the inverter 4 also controls the high-frequency switching of switching elements Q1 to Q4 for the inverter while monitoring with the output current monitor 12, so as to provide an output current I0 of the sine wave. |
