A method for controlling a power conversion device, the power conversion device comprising: - an alternating-current wave generation circuit comprising a switching element and configured to convert input power into an alternating-current wave, - a controller configured to control the switching element to regulate the alternating-current wave, and - a rectifier circuit - which is configured to rectify the alternating-current wave generated by the alternating-current wave generation circuit with a configuration in which a rectifier capacitor and a diode to subject the alternating-current wave to half-wave rectification are connected in parallel, and - which comprises a filter (75; 77) that is implemented by a filter coil and a filter capacitor, characterized in that the method comprises detecting an impedance of the rectifier capacitor, the method further comprises - by controlling a drive frequency of the switching element - - regulating the alternating-current wave input to the rectifier capacitor by the controller to increase a frequency of the alternating-current wave generated by the alternating-current wave generation circuit so as to decrease an output voltage of the power conversion device when the impedance of the rectifier capacitor is increased above a set value; and - regulating the alternating-current wave input to the rectifier capacitor by the controller to decrease the frequency of the alternating-current wave generated by the alternating-current wave generation circuit so as to increase the output voltage of the power conversion device when the impedance of the rectifier capacitor is decreased below the set value, and thereby suppressing a change in the impedance of the rectifier capacitor by regulating the period of time during which the AC wave is input to the rectifier capacitor. the power conversion device comprising: - an alternating-current wave generation circuit comprising a switching element and configured to convert input power into an alternating-current wave, - a controller configured to control the switching element to regulate the alternating-current wave, and - a rectifier circuit - which is configured to rectify the alternating-current wave generated by the alternating-current wave generation circuit with a configuration in which a rectifier capacitor and a diode to subject the alternating-current wave to half-wave rectification are connected in parallel, and - which comprises a filter (75; 77) that is implemented by a filter coil and a filter capacitor, characterized in that - an alternating-current wave generation circuit comprising a switching element and configured to convert input power into an alternating-current wave, - a controller configured to control the switching element to regulate the alternating-current wave, and - a rectifier circuit - which is configured to rectify the alternating-current wave generated by the alternating-current wave generation circuit with a configuration in which a rectifier capacitor and a diode to subject the alternating-current wave to half-wave rectification are connected in parallel, and - which comprises a filter (75; 77) that is implemented by a filter coil and a filter capacitor, characterized in that - which is configured to rectify the alternating-current wave generated by the alternating-current wave generation circuit with a configuration in which a rectifier capacitor and a diode to subject the alternating-current wave to half-wave rectification are connected in parallel, and - which comprises a filter (75; 77) that is implemented by a filter coil and a filter capacitor, characterized in that the method comprises detecting an impedance of the rectifier capacitor, the method further comprises - by controlling a drive frequency of the switching element - - regulating the alternating-current wave input to the rectifier capacitor by the controller to increase a frequency of the alternating-current wave generated by the alternating-current wave generation circuit so as to decrease an output voltage of the power conversion device when the impedance of the rectifier capacitor is increased above a set value; and - regulating the alternating-current wave input to the rectifier capacitor by the controller to decrease the frequency of the alternating-current wave generated by the alternating-current wave generation circuit so as to increase the output voltage of the power conversion device when the impedance of the rectifier capacitor is decreased below the set value,