Patent ID: 8643316

Claim:
A power conversion device, comprising: a first power converter which obtains a DC voltage from a power supply; a capacitor which is connected to an output side of the first power converter; a second power converter which converts the DC voltage of the capacitor into an AC voltage and outputs the AC voltage to a synchronous machine; rotation information detection means which detects rotation information of the synchronous machine; and control means which controls the first power converter and the second power converter, based on the rotation information detected by the rotation information detection means, wherein the control means controls, during a coasting operation mode, the second power converter to stop after the capacitor is boosted to a value corresponding to a charge voltage command, and based on the rotation information of the synchronous machine detected by the rotation information detection means, the control means controls the second power converter so that a voltage generated at a terminal of the synchronous machine is lower than or equal to a charge voltage of the capacitor and controls the first power converter so that the charge voltage of the capacitor is equal to or higher than the voltage generated at the terminal of the synchronous machine at the time of re-activation of the second power converter from the coasting operation mode.