A power conversion device (100, 100a, 100b, 101) comprising: - an AC/DC converter (4, 4a, 4b, 4c) configured to perform power factor correction control for a single-phase AC power supply and to convert AC power from the single-phase AC power supply, to DC power; - a DC/DC converter (6, 6a) which is connected to a DC side of the AC/DC converter (4, 4a, 4b, 4c) and is configured to perform voltage conversion of DC power and output it to a load; - a DC capacitor connected between positive and negative DC buses between the AC/DC converter (4, 4a, 4b, 4c) and the DC/DC converter (6, 6a); and - a control circuit (10, 10a, 10b, 10c) configured to perform output control for the AC/DC converter (4, 4a, 4b, 4c) and the DC/DC converter (6, 6a), wherein the control circuit (10, 10a, 10b, 10c) is configured to perform output control for the DC/DC converter (6, 6a) using an output current command, wherein the control circuit (10, 10a, 10b, 10c) is configured to superimpose, onto a DC current command which is a load current command value, IL*, having only a DC component, an AC current command determined to suppress ripple voltage of the DC capacitor, having a minimum value at a zero cross phase of voltage vac or current iac of the single-phase AC power supply and having a maximum value at a peak phase thereof, to generate the output current command for the DC/DC converter (6, 6a), wherein the control circuit (10, 10a, 10b, 10c) is configured to control supplying constant DC current to the load and to set an amplitude of the AC current command so as to reduce a charge/discharge current (iin-iout) of the DC capacitor with using a limitation value (Lim) set for the load, characterised in that the amplitude of the AC current command is determined on the basis of an amplitude target value of ripple voltage ΔVdc* of the DC capacitor, and is calculated using the following expression VL/Vdc IL * − 2 ω Cdc ⋅ Δ Vdc *, or the amplitude of the AC current command is determined on the basis of an amplitude target value of ripple current ΔIrp* of the DC capacitor and is calculated using the following expression IL * − Vdc/VL ⋅ Δ Irp *, wherein VL indicates a DC voltage of the load, Vdc indicates a DC voltage component of the DC capacitor, Cdc is an electrostatic capacitance of the DC capacitor, and ω is a frequency of voltage vac or current iac of the AC power supply. - an AC/DC converter (4, 4a, 4b, 4c) configured to perform power factor correction control for a single-phase AC power supply and to convert AC power from the single-phase AC power supply, to DC power; - a DC/DC converter (6, 6a) which is connected to a DC side of the AC/DC converter (4, 4a, 4b, 4c) and is configured to perform voltage conversion of DC power and output it to a load; - a DC capacitor connected between positive and negative DC buses between the AC/DC converter (4, 4a, 4b, 4c) and the DC/DC converter (6, 6a); and - a control circuit (10, 10a, 10b, 10c) configured to perform output control for the AC/DC converter (4, 4a, 4b, 4c) and the DC/DC converter (6, 6a), wherein the control circuit (10, 10a, 10b, 10c) is configured to perform output control for the DC/DC converter (6, 6a) using an output current command, wherein the control circuit (10, 10a, 10b, 10c) is configured to superimpose, onto a DC current command which is a load current command value, IL*, having only a DC component, an AC current command determined to suppress ripple voltage of the DC capacitor, having a minimum value at a zero cross phase of voltage vac or current iac of the single-phase AC power supply and having a maximum value at a peak phase thereof, to generate the output current command for the DC/DC converter (6, 6a), wherein the control circuit (10, 10a, 10b, 10c) is configured to control supplying constant DC current to the load and to set an amplitude of the AC current command so as to reduce a charge/discharge current (iin-iout) of the DC capacitor with using a limitation value (Lim) set for the load, characterised in that the amplitude of the AC current command is determined on the basis of an amplitude target value of ripple voltage ΔVdc* of the DC capacitor, and is calculated using the following expression VL/Vdc IL * − 2 ω Cdc ⋅ Δ Vdc *, or the amplitude of the AC current command is determined on the basis of an amplitude target value of ripple current ΔIrp* of the DC capacitor and is calculated using the following expression IL * − Vdc/VL ⋅ Δ Irp *, wherein VL indicates a DC voltage of the load, Vdc indicates a DC voltage component of the DC capacitor, Cdc is an electrostatic capacitance of the DC capacitor, and ω is a frequency of voltage vac or current iac of the AC power supply.