A power inverter comprising: a plurality of power switches (104, 216) configured to convert DC power supplied from a first DC power source into AC power used to drive an electrical motor; a first control circuit configured to be supplied from a second DC power source and which is configured to output a first control signal (108P, 108N, 315) configured to control an operation of the plurality of power switches (104, 216); an electric storage circuit configured to store the DC power by performing charging based on AC power generated by the electrical motor; a power source circuit (311, 1011) configured to supply power based on the first DC power source or the DC power supplied from the electric storage circuit; a second control circuit configured to be supplied from the power source circuit (311, 1011) and which is configured to determine whether the second DC power source is normal and is configured to output a second control signal configured to control the operation of the plurality of power switches (104, 216) when determining that the second DC power source is not normal; and a driving circuit configured to be supplied from the power source circuit (311, 1011) and which is configured to output a driving signal configured to operate the plurality of power switches (104, 216) based on the first or second control signal (108P,108N, 307), wherein the plurality of power switches (104, 216) are one of power switches of an upper arm connected to a high-voltage side of the first DC power source and power switches of a lower arm connected to a low-voltage side of the first DC power source, and a plurality of series circuits in which the power switches (104, 216) of the upper arm and the power switches (104, 216) of the lower arm are connected in series are connected in parallel to the electric storage circuit with respect to the first DC power source, characterised in that: the power inverter further comprises a voltage measurement circuit (302, 306) configured to measure a voltage of the electric storage circuit; the second control circuit is configured to output the second control circuit based on the voltage of the electric storage circuit measured by the voltage measurement circuit (302, 306); and when the voltage of the electric storage circuit is greater than a predetermined first voltage value, the second control circuit is configured to output the second control signal configured to: - either turn on all power switches of the upper arm and turn off all power switches of the lower arm; - or turn on all power switches of the lower arm and turn off al power switches of the upper arm. a plurality of power switches (104, 216) configured to convert DC power supplied from a first DC power source into AC power used to drive an electrical motor; a first control circuit configured to be supplied from a second DC power source and which is configured to output a first control signal (108P, 108N, 315) configured to control an operation of the plurality of power switches (104, 216); an electric storage circuit configured to store the DC power by performing charging based on AC power generated by the electrical motor; a power source circuit (311, 1011) configured to supply power based on the first DC power source or the DC power supplied from the electric storage circuit; a second control circuit configured to be supplied from the power source circuit (311, 1011) and which is configured to determine whether the second DC power source is normal and is configured to output a second control signal configured to control the operation of the plurality of power switches (104, 216) when determining that the second DC power source is not normal; and a driving circuit configured to be supplied from the power source circuit (311, 1011) and which is configured to output a driving signal configured to operate the plurality of power switches (104, 216) based on the first or second control signal (108P,108N, 307), wherein the plurality of power switches (104, 216) are one of power switches of an upper arm connected to a high-voltage side of the first DC power source and power switches of a lower arm connected to a low-voltage side of the first DC power source, and a plurality of series circuits in which the power switches (104, 216) of the upper arm and the power switches (104, 216) of the lower arm are connected in series are connected in parallel to the electric storage circuit with respect to the first DC power source, the power inverter further comprises a voltage measurement circuit (302, 306) configured to measure a voltage of the electric storage circuit; the second control circuit is configured to output the second control circuit based on the voltage of the electric storage circuit measured by the voltage measurement circuit (302, 306); and - either turn on all power switches of the upper arm and turn off all power switches of the lower arm; - or turn on all power switches of the lower arm and turn off al power switches of the upper arm.