Patent ID: 9667166
Date: 2017-05-30
CPC Classifications: H02M

Claim:
1. A five-level converting device, comprising: an alternating current (AC) terminal; a bus capacitor module, having a positive terminal, a negative terminal and a neutral point; a first switch module, having two terminals connected to the neutral point of the bus capacitor module and the AC terminal respectively, wherein the first switch module comprises a plurality of bidirectional switching circuits cascaded to each other, each of the bidirectional switching circuits comprises two first switching units reversely connected in series; a second switch module, having two terminals connected to the positive terminal of the bus capacitor module and the AC terminal respectively, wherein the second switch module comprises a plurality of second switching units connected in series; a third switch module, having two terminals connected to the negative terminal of the bus capacitor module and the AC terminal respectively, wherein the third switch module comprises a plurality of third switching units connected in series; a first flying capacitor unit, connected across the first switch module and the second switch module; and a second flying capacitor unit, connected across the first switch module and the third switch module, wherein the first flying capacitor unit and the second flying capacitor unit are connected to different connection points between the first switching units of the first switch module, wherein the first flying capacitor unit has a first end connected to the second switch module and a second end connected to a first connection point of the first switch module without connecting any other flying capacitor unit, and the second flying capacitor unit has a first end connected to the third switch module and a second end connected to a second connection point of the first switch module without connecting any other flying capacitor unit, wherein one or more of the first switching units are inserted between the first and second connection points of the first switch module, so that the first connection point is isolated from the second connection point when the one or more of the first switching units are turned off.