MULTILEVEL POWER CONVERTING APPARATUS

摘要

A multilevel power converting apparatus comprising two sets of multilevel PWM controlled power supply converters for converting a DC voltage into multilevel AC voltage pulses by means of PWM control, positive DC sides and negative DC sides thereof being connected with each other, the first of the power supply converters having its AC side connected with an AC power source of a fixed frequency, the second of the power supply converters having its AC side outputting variable voltages of variable frequencies and its output terminal being connected with a load, and the first and second power supply converters having their DC sides respectively connected with a first and a second DC stage circuit each thereof being formed of a plurality of serially connected filter capacitors, wherein the center voltage points of the first DC stage circuit and the second DC stage circuit are connected with each other and voltage controlling of the center voltage point is carried out on the side of the first power supply converter. <IMAGE>