POWER CONVERSION DEVICE AND TEST METHOD FOR SAME
FIG2 is a circuit block diagram showing a configuration of a unit converter shown in FIG1
FIG2 is a circuit block diagram showing a configuration of unit converter 5. In FIG2, unit converter 5 includes AC terminals 5a and 5b, a switch S7, an inverter 10, DC lines PL and NL, a capacitor 15, a voltage detector 16, and a driver 17. When gate signals Auv and Buv are at "H" level and "L" level, respectively, IGBTs 11 and 14 included in the corresponding inverter 10 turn on and IGBTs 12 and 13 turn off. In this case, in FIG2, the positive-side terminal (positive-side DC line PL) of capacitor 15 is connected to AC terminal 5a through IGBT 11, AC terminal 5b is connected to the negative-side terminal (negative-side DC line NL) of capacitor 15 through IGBT 14, and the terminal-to-terminal voltage of capacitor 15 is output between AC terminals 5a and 5b. In other words, a positive DC voltage is output between AC terminals 5a and 5b.
circuit block diagram
5
unit converters unit converter
11
IGBTs
16
voltage detector
10
inverter inverters
15
capacitor capacitors
['1. A power conversion device comprising: three arms that are delta-connected; each of the three arms including a capacitor configured to store DC power, and an inverter configured to convert DC power into AC power; a first controller configured to control the inverter of each of the three arms such that circulating current of the three arms follows a first reference in a test period in which a power system is cut off from the three arms; and a second controller configured to control the inverter of each of the three arms such that electric power transferred between the power system and the three arms follows a second reference in normal operation in which there is electrical continuity between the power system and the three arms, wherein it is determined whether the power conversion device is normal, based on the circulating current in the test period.', '8. The power conversion device according to claim 1, wherein each of the three arms includes a plurality of unit converters, each of the unit converters includes the capacitor and the inverter, and a plurality of the inverters are cascaded.']