MULTILEVEL POWER CONVERSION CIRCUIT

摘要

A multilevel power conversion circuit using a flying capacitor(s) can include two bidirectional switches connected in series between a middle potential terminal of DC power supplies and a conversion circuit using semiconductor switches. Gate driving circuits for the bidirectional switches are provided with a short-circuit fault detecting circuit for detecting short-circuit of the semiconductor switching device composing the bidirectional switch circuit in an OFF signal period. Upon detection of a short-circuit fault, all semiconductor switching devices are interrupted to stop the whole system.

主权项

1. A multilevel power conversion circuit for converting DC power to AC power or AC power to DC power, one phase of which comprising:
a first semiconductor switch series circuit connected between a positive potential terminal and a negative potential terminal of a DC power supply circuit having the positive potential terminal, the negative potential terminal, and a middle potential terminal, the first semiconductor switch series circuit being composed of:
a first semiconductor switch group composed of a plurality of semiconductor switches connected in series,a first semiconductor switch,a second semiconductor switch, anda second semiconductor switch group composed of a plurality of semiconductor switches connected in series,these four components being connected in series in this order; a second semiconductor switch series circuit composed of a third semiconductor switch and a fourth semiconductor switch connected in series between a node between the first semiconductor switch group of the first semiconductor switch series circuit and the first semiconductor switch and a node between the second semiconductor switch and the second semiconductor switch group; a capacitor connected in parallel with the second semiconductor switch series circuit; and a bidirectional switch circuit capable of bidirectional switching connected between a series connection point of the second semiconductor switch series circuit and the middle potential terminal of the DC power supply circuit; the multilevel power conversion circuit having an AC terminal at a series connection point between the first semiconductor switch and the second semiconductor switch; and the bidirectional switch circuit having at least two semiconductor switching devices connected in series with the same current flowing direction.