A control circuit applied to a lifting platform controls a motor to adjust the height of a platform. The control circuit includes an AC/DC conversion circuit, a DC/DC conversion circuit, a detection unit, and a control unit. The detection unit detects an output end of the AC/DC conversion circuit and provides a detection signal. The control unit provides a PWM signal according to the detection signal to control the DC/DC conversion circuit so that the DC/DC conversion circuit converts a DC voltage to an output voltage. When the control unit realizes that the DC voltage or a DC power provided by the AC/DC conversion circuit is less than a power supply threshold according to the detection signal, the control unit decreases a duty cycle of the PWM signal to maintain the DC voltage or the DC power to be greater than or equal to the power supply threshold.

A motor control system includes a variable voltage supply in signal communication with a direct current (DC) motor. The DC motor includes a rotor induced to rotate in response to a drive current generated by a variable supply voltage delivered by the voltage supply. The rotation of the rotor 103 generates a mechanical force that drives a component. A ripple count circuit 104 is configured to filter the drive current based on a rotational speed (ω) of the rotor 103 to generate a filtered drive current signal, and to generate a varying threshold based on the filtered drive current signal. Based on a comparison between the filtered drive current signal and the varying threshold, the ripple count circuit 104 generates a pulsed output signal indicative of the rotational speed (ω) of the rotor and a rotational position (θ) of the rotor.

A motor control system includes a variable voltage supply in signal communication with a direct current (DC) motor. The DC motor includes a rotor induced to rotate in response to a drive current generated by a variable supply voltage delivered by the voltage supply. The rotation of the rotor (103) generates a mechanical force that drives a component. A ripple count circuit (104) is configured to filter the drive current based on a rotational speed (ω) of the rotor (103) to generate a filtered drive current signal, and to generate a varying threshold based on the filtered drive current signal. Based on a comparison between the filtered drive current signal and the varying threshold, the ripple count circuit (104) generates a pulsed output signal indicative of the rotational speed (ω) of the rotor and a rotational position (θ) of the rotor.

A motor control system includes a variable voltage supply in signal communication with a direct current (DC) motor. The DC motor includes a rotor induced to rotate in response to a drive current generated by a variable supply voltage delivered by the voltage supply. The rotation of the rotor 103 generates a mechanical force that drives a component. A ripple count circuit 104 is configured to filter the drive current based on a rotational speed (ω) of the rotor 103 to generate a filtered drive current signal, and to generate a varying threshold based on the filtered drive current signal. Based on a comparison between the filtered drive current signal and the varying threshold, the ripple count circuit 104 generates a pulsed output signal indicative of the rotational speed (ω) of the rotor and a rotational position (θ) of the rotor.

A wiper motor control circuit controls a drive circuit such that an actual speed of a wiper speed computed based on change in a rotation angle of an output shaft of the wiper motor detected by a rotation angle sensor that detects the rotation angle becomes a target speed corresponding to a position of a wiper blade indicated by the rotation angle detected by the rotation angle sensor. The wiper motor control circuit also controls the drive circuit so as to apply a braking current in the wiper motor when the actual speed has exceeded a threshold value when the rotation angle detected by the rotation angle sensor indicates a return position of the wiper blade.

A method of operating a device to receive a print medium is disclosed. Rotation of a receiving device to receive a print medium is detected, whereby the rotation is caused by an external force. An assisting force is applied to further rotate the receiving device in response to the detected rotation.

A control circuit applied to a lifting platform controls a motor to adjust the height of a platform. The control circuit includes an AC/DC conversion circuit, a DC/DC conversion circuit, a detection unit, and a control unit. The detection unit detects an output end of the AC/DC conversion circuit and provides a detection signal. The control unit provides a PWM signal according to the detection signal to control the DC/DC conversion circuit so that the DC/DC conversion circuit converts a DC voltage to an output voltage. When the control unit realizes that the DC voltage or a DC power provided by the AC/DC conversion circuit is less than a power supply threshold according to the detection signal, the control unit decreases a duty cycle of the PWM signal to maintain the DC voltage or the DC power to be greater than or equal to the power supply threshold.

A motor control system includes a variable voltage supply in signal communication with a direct current (DC) motor. The DC motor includes a rotor induced to rotate in response to a drive current generated by a variable supply voltage delivered by the voltage supply. The rotation of the rotor (103) generates a mechanical force that drives a component. A ripple count circuit (104) is configured to filter the drive current based on a rotational speed () of the rotor (103) to generate a filtered drive current signal, and to generate a varying threshold based on the filtered drive current signal. Based on a comparison between the filtered drive current signal and the varying threshold, the ripple count circuit (104) generates a pulsed output signal indicative of the rotational speed () of the rotor and a rotational position () of the rotor.

According to one embodiment, there is provided a control device including a detecting circuit, a control circuit and a drive circuit. The detecting circuit detects changes in a current flowing between a node and a smoothing circuit, the node being to which a DC brush motor, a power supply circuit and the smoothing circuit can be electrically connected via respective different lines. The control circuit generates a control signal to control rotation speed of the DC brush motor according to the detected changes in the current. The drive circuit drives the DC brush motor according to the control signal.

A method for controlling a motor of a derailleur of a bicycle electronic gearshift during a displacement from an initial position (A) towards a destination position (B) includes the step of feedback controlling the current (I(t)) absorbed by the motor. A controller of an electric motor of a derailleur of a bicycle electronic gearshift is configured to carry out a feedback control of the current (I(t)) absorbed by the motor during a displacement from an initial position (A) towards a destination position (B).