Motor control apparatus that controls motor based on result of detection by position detection sensor that detects rotational position of rotor of motor, and image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorHiroki Sato
Life of this patent
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Abstract
A motor control unit performs driving control for a stepping motor by using vector control, and detects a rotational position θ of a rotor of the stepping motor, the rotational position θ being required for vector control, by using a position detection unit, based on a pulse signal that is output from an encoder. The motor control unit determines whether or not there is an abnormality in the pulse signal output from the encoder. Upon determining that there is an abnormality in the pulse signal, the motor control unit corrects a detection value of the position θ of the rotor of the stepping motor so as to compensate an error caused by the abnormality in the pulse signal.
Claims15
A motor control apparatus that controls a driving current flowing in each of windings of a motor based on a designated position indicating a target position of a rotor of the motor, comprising:
- a counter configured to count a number of pulse signals that are output from a position detection sensor, which is provided in the motor, according to a change in a rotational position of the rotor;
- a position determiner configured to determine the rotational position of the rotor based on a count value of the counter;
- a controller configured to control the driving current flowing in each of the windings of the motor based on both a value of a torque current component and a value of an excitation current component so that a difference between the designated position and the rotational position determined by the position determiner is decreased, the torque current component being a current component that has a current value represented in a rotating coordinate system based on the rotational position and generates torque in the rotor, and the excitation current component being a current component that has a current value represented in the rotating coordinate system based on the rotational position and affects an intensity of a magnetic flux penetrating each of the windings of the motor;
- and
- a discriminator configured to discriminate whether or not a time interval between two consecutive pulses among the pulse signals output from the position detection sensor is abnormal,
- wherein the counter is configured to, if the time interval is discriminated to be abnormal, correct the count value.
An image forming apparatus comprising:
- an image forming unit configured to form an image on a recording material;
- a motor having a rotor and windings and configured to drive a roller that conveys the recording material;
- a counter configured to count a number of pulse signals that are output from a position detection sensor, which is provided in the motor, according to a change in a rotational position of the rotor;
- a position determiner configured to determine the rotational position of the rotor based on a count value of the counter;
- a controller configured to control driving current flowing in each of the windings of the motor based on both a value of a torque current component and a value of an excitation current component so that a difference between the designated position and the rotational position determined by the position determiner is decreased, the torque current component being a current component that has a current value represented in a rotating coordinate system based on the rotational position, and generates torque in the rotor, and the excitation current component being a current component that has a current value represented in the rotating coordinate system based on the rotational position, and affects an intensity of a magnetic flux penetrating each of the windings of the motor;
- and
- a discriminator configured to discriminate whether or not a time interval between two consecutive pulses among the pulse signals output from the position detection sensor is abnormal,
- wherein the counter is configured to, if the time interval is discriminated to be abnormal, correct the count value.
Dependencies are inferred from the claim text.