POWER CONVERSION DEVICE, CONTROL DEVICE AND CONTROL METHOD THEREOF, AND POWER GENERATION SYSTEM

The invention is directed to a power conversion device including a main circuit unit (1) having a plurality of arms to which outputs of a plurality of converters (cells) are connected in series, a driving unit (105) (PWM control unit) which generates a driving signal for driving a plurality of semiconductor switching elements in the main circuit unit (1) according to a voltage command and outputs the signal to the plurality of semiconductor switching elements, an AC control unit (102) (AC current control unit) which generates AC voltage commands for the number of phases on a AC side for controlling AC power of a target to be controlled, and a DC control unit (103) (capacitor average voltage control unit) which generates a DC voltage command for setting an average value of DC voltages of the plurality of capacitors in the main circuit unit (1) to a predetermined value, in which the target to be controlled (rotating machine) is connected to the AC side of the main circuit unit (1), and a voltage command inputted by the driving unit (105) includes the AC voltage command and the DC voltage command.