Patent ID: 8542502

Claim:
An electrical power conversion apparatus comprising: a converter that converts an AC power from an AC power source into a DC power; a capacitor that stores the DC power produced from the converter; an inverter that converts to an AC power the DC power stored in the capacitor; a voltage control unit that calculates command values for an AC voltage to be output from the inverter, to control the inverter so that the AC voltage becomes the command value; a current measuring instrument that measures an AC current output from the inverter; a ripple detection unit that receives the AC voltage command values calculated by the voltage control unit and the AC currents measured by the current measuring instrument, to detect a ripple of an active power output from the inverter; a voltage measuring instrument that measures the voltage across the capacitor; a DC voltage command generation unit that calculates a command value of the voltage across the capacitor according to a frequency of the AC voltage output from the inverter; and a DC voltage control unit that receives the voltage measured by the voltage measuring instrument and the command value calculated by the DC voltage command generation unit, to control the converter so that the voltage across the capacitor becomes the command value, wherein the DC voltage command generation unit makes the command value of the voltage across the capacitor higher than usual in a situation where the frequency of AC voltage output from the inverter is within a predetermined range including a frequency of a ripple component of the voltage across the capacitor, and the voltage control unit receives the ripple component derived from the ripple detection unit, to calculate the command values for the AC voltage output from the inverter so that the ripple component is reduced.