Patent ID: 8552669
Filing Date: 2013-10-08
Classification: A01D,H02P

Abstract:
1. A duty ratio control device that controls a control duty ratio that determines a magnitude of voltage to be applied to a motor mounted on an electric power tool, the duty ratio control device comprising: a duty ratio calculation unit that, when an acceleration manipulation for accelerating a rotation speed of the motor is performed, calculates the control duty ratio per predetermined timing based on a value of at least one parameter so that the rotation speed of the motor reaches a target rotation speed corresponding to the acceleration manipulation, wherein the control duty ratio is calculated to be larger as the value of the at least one parameter is larger; and a parameter setting unit that sets the value of the at least one parameter, wherein the value of the at least one parameter set for a reacceleration manipulation is larger than the value of the at least one parameter set for an initial acceleration manipulation, the reacceleration manipulation being the acceleration manipulation performed again during a deceleration period in which the motor is being decelerated by a stopping manipulation that stops rotation of the motor, and the initial acceleration manipulation being the acceleration manipulation performed when the rotation of the motor is being stopped.