Patent ID: 7990099

Claim:
A power converting device for an electric train, comprising: a power converter that converts direct-current power into alternating-current power; an alternating-current motor that is driven by the alternating-current power output from the power converter; a primary control unit that outputs a power-running notch command that determines an acceleration speed for the electric train; and a control unit that controls an amount of the alternating-current power output from the power converter based on the power-running notch command, wherein the control unit sets the amount of the alternating-current power output from the power converter to zero without a delay after receiving an OFF signal of the power-running notch command during power running, said control unit includes: a torque-command generating unit that generates a torque command based on the power-running notch command and that sets the torque command to zero within a time period from 0.1 microsecond to 25 milliseconds after input of the OFF signal of the power-running notch command to the control unit; and a voltage control unit that controls a voltage output from the power converter according to the torque command, wherein the torque-command generating unit includes: a first torque generating unit that sets the torque command to zero within the time period from 0.1 microsecond to 25 milliseconds after input of the OFF signal of the power-running notch command while the primary control unit issues any one of a one-notch signal, a minimum notch command, and a command representing an acceleration speed corresponding to a torque command of 500 Newton-meter or smaller; a second torque generating unit that sets the torque command to zero in 100 milliseconds or more after input of the OFF signal of the power-running notch command while the primary control unit issues a power-running notch command other than the one-notch signal, the minimum notch command, and the command representing an acceleration speed corresponding to a torque command of 500 Newton-meter or smaller; and a switching unit that switches between the first torque generating unit and the second torque generating unit based on the power-running notch command issued from the primary control unit.