Patent ID: 8496085
Filing Date: 2013-07-30
Classification: B62D,H02P

Abstract:
1. A motor control device that calculates an estimate of a rotation speed of an electric motor on the basis of a counter electromotive force generated in an armature winding of the electric motor, and that drives the electric motor using the estimate, comprising: a current detection unit that detects a current flowing through the electric motor; a voltage detection unit that detects a voltage applied to the electric motor; a determining unit that determines whether the rotation speed of the electric motor is lower than or equal to a predetermined value that is substantially zero; a characteristic holding unit that holds a correlation between a current flowing through the electric motor and a resistance of the electric motor as a current-resistance characteristic; a resistance calculation unit that, when it is determined by the determining unit that the rotation speed of the electric motor is lower than or equal to the predetermined value, calculates a resistance value of the electric motor on the basis of a detected current value obtained by the current detection means and a detected voltage value detected by the voltage detection means; an estimate calculation unit that calculates a velocity estimate indicating the rotation speed of the electric motor on the basis of the detected current value obtained by the current detection unit, the detected voltage value obtained by the voltage detection unit and a resistance value that is associated with the detected current value by the current-resistance characteristic or the resistance value calculated by the resistance calculation unit; and a characteristic updating unit that updates the current-resistance characteristic on the basis of the resistance value calculated by the resistance calculation unit and the detected current value used to calculate the resistance value.