Patent ID: 8395345

Claim:
A valve control device for a valve mechanism to which a return torque is applied in an opening direction or a closing direction of a valve, the valve control device controlling opening and closing of the valve in a balance between the return torque and a motor torque provided by control of a motor for applying a torque in a direction opposite to a direction of the return torque, the valve control device comprising: a detection position converter for converting an electrical angle detection position, which is a present position of the motor detected by a position detection sensor of a pulse output type and changes stepwise, into a mechanical angle detection position; a position control system for outputting a q-axis current command based on a deviation between a target position command and the mechanical angle detection position of the motor; and a current control system constituting a current feedback system for distributing the q-axis current command to a phase current command of each of phases of the motor based on the electrical angle detection position which changes stepwise, generating a phase voltage command of the each of the phases based on a current deviation between the phase current command and a fed-back estimated current of the each of the phases, obtaining an estimated induced voltage of the each of the phases based on the electrical angle detection position which changes stepwise and an induced voltage actually measured in advance, and obtaining an estimated current of the each of the phases based on the estimated induced voltage and the phase voltage command, and outputting a phase voltage command to which saturation processing is finally applied in an actually-used voltage range.