An electric power converter which has improved accuracy in compensation of a dead time. A motor driving system employing the electric power converter is also provided. A power module includes a plurality of switching devices connected in series and converts DC power to AC power. A control circuit produces a voltage command value in accordance with a control command inputted from the exterior, and produces gate signals to drive the switching devices of the power module corresponding to a final voltage command value which is obtained from the voltage command value with dead time compensation. A dead time compensation logic circuit calculates a final dead time compensation voltage based on a change rate of the voltage command value, a gain (dead time compensation voltage value), and a polarity of a current, the gain being calculated from a DC voltage value supplied to the electric power converter, a dead time, and a switching frequency.