MULTILEVEL POWER CONVERTOR

摘要

Basic circuit of U phase includes first to fourth semiconductor elements (SU1.1 to SU1.4) connected between positive and negative ends of DC voltage source (DCC1), fifth semiconductor element (SU1.5) connected to a common connection point of the first and second semiconductor elements (SU1.1, SU1.2), and sixth semiconductor element (SU1.6) connected to a common connection point of the third and fourth semiconductor elements (SU1.3, SU1.4). Flying capacitor (FC1) is inserted between the fifth semiconductor element (SU1.5) and the sixth semiconductor element (SU1.6). Voltage selection circuits have the common connection points of the second and third semiconductor elements (SU1.2, SU1.3) of the respective basic circuits as input terminals, and includes semiconductor elements (SU1 to SU4) between the input terminals and output terminals (U, V, W). Consequently, it is possible to output arbitrary voltage in all phases in multilevel power convertor, and to simplify control for outputting arbitrary voltage level in all phases.

主权项

1. A multilevel power convertor that generates AC outputs with a plurality of voltage levels obtained by conversion of voltages of a DC voltage source and a flying capacitor, the multilevel power convertor comprising:
N DC voltage sources (N≧2) that are connected in series to each other; basic circuits of M phases (M≧3), each of which includes first to fourth semiconductor elements that are sequentially connected in series between positive and negative electrodes of each of the N DC voltage sources; a fifth semiconductor element whose one end is connected to a common connection point of the first and second semiconductor elements; and a sixth semiconductor element whose one end is connected to a common connection point of the third and fourth semiconductor elements; a flying capacitor that is inserted between the other ends of the fifth semiconductor elements of all the phases and the other ends of the sixth semiconductor elements of all the phases, the flying capacitor being in common to the M phases; and voltage selection circuits of the M phases, each of which has common connection points of the second and third semiconductor elements of each basic circuit as input terminals, includes semiconductor elements between the input terminals and an output terminal, and outputs a potential of any one of the input terminals from the output terminal by selectively controlling ON/OFF of the semiconductor elements.