A normalized-link-current estimation unit adopts a first value calculated by using a virtual DC voltage command, a phase and an amplitude of a single-phase AC voltage, and a distribution factor, as an estimated value of a value obtained by normalizing a link current flowing from a DC link to an inverter. A calculation unit determines a second value calculated by using the virtual DC voltage command, a rectified voltage, and a both-end voltage. When a normalized current command is less than a product of the first value and the second value, a normalized charge command is set to 0 and a rectifying duty is determined by dividing the normalized current command by the first value.