A motor drive device of an embodiment includes a first drive circuit, a second drive circuit, a first detection circuit, a second detection circuit, a third detection circuit, a fourth detection circuit, and an output circuit. The first drive circuit drives a first phase of a motor. The second drive circuit drives a second phase of the motor. The first detection circuit detects a first anomaly of the first phase. The second detection circuit detects the first anomaly of the second phase. The third detection circuit detects a second anomaly of the first phase. The fourth detection circuit detects the second anomaly of the second phase. The output circuit outputs an occurred anomaly as a flag signal based on results of detection by the first to fourth detection circuits.

A motor drive device of an embodiment includes a first drive circuit, a second drive circuit, a first detection circuit, a second detection circuit, a third detection circuit, a fourth detection circuit, and an output circuit. The first drive circuit drives a first phase of a motor. The second drive circuit drives a second phase of the motor. The first detection circuit detects a first anomaly of the first phase. The second detection circuit detects the first anomaly of the second phase. The third detection circuit detects a second anomaly of the first phase. The fourth detection circuit detects the second anomaly of the second phase. The output circuit outputs an occurred anomaly as a flag signal based on results of detection by the first to fourth detection circuits.

A method for detecting stall of a multiphase motor operated in a sinusoidal micro-stepped mode. The method comprises: a) measuring at least one phase current and/or measuring the sum of all phase currents at regular time intervals synchronous with the micro-steps, b) calculating the difference between the measured phase current at a first moment and the measured phase current of the same phase at a previous moment and/or the difference between the measured sum of all phase currents at a first moment and the measured sum of all phase currents at a previous synchronous moment, c) analyzing the series of obtained current differences so as to generate a stall detection signal.

An apparatus includes a magnetometer-based current sensor (e.g., a Hall-effect or fluxgate-based current sensor) configured to sense a magnetic field generated by a current in at least one conductor connecting a motor drive output to a motor and to responsively produce a first current sense signal and a magnetometer-based voltage sensor (e.g., a Hall-effect or fluxgate-based voltage sensor) configured to sense a magnetic field generated in response to a voltage of the at least one conductor and to responsively produce a first voltage sense signal. The apparatus further includes a signal conversion circuit configured to receive the first current sense signal and the first voltage sense signal and to generate a second current sense input and a second voltage sense input for provision to a current sense input and a voltage sense input, respectively, of a motor protection relay that protects the motor.

An apparatus includes a magnetometer-based current sensor (e.g., a Hall-effect or fluxgate-based current sensor) configured to sense a magnetic field generated by a current in at least one conductor connecting a motor drive output to a motor and to responsively produce a first current sense signal and a magnetometer-based voltage sensor (e.g., a Hall-effect or fluxgate-based voltage sensor) configured to sense a magnetic field generated in response to a voltage of the at least one conductor and to responsively produce a first voltage sense signal. The apparatus further includes a signal conversion circuit configured to receive the first current sense signal and the first voltage sense signal and to generate a second current sense input and a second voltage sense input for provision to a current sense input and a voltage sense input, respectively, of a motor protection relay that protects the motor.

A voltage regulator includes an output transistor, an error amplifier coupled to the output transistor, a cascode transistor coupled to the output transistor in series, and a cascode bias circuit coupled to the cascode transistor and the output transistor. The output transistor is configured to generate an output signal at a first voltage. The error amplifier is configured to receive a reference signal. The cascode bias circuit is configured to bias the cascode transistor such that, in response to a drain-to-source short circuit of the output transistor, the cascode transistor generates the output signal at the first voltage.

Disclosed herein are methods for detecting and correcting a fault induced delayed voltage recovery event in an electric power transmission and distribution system. In some embodiments, a fault detection subsystem may receive an indication of a fault in the electric power transmission and distribution system. The system may also include a load analysis subsystem to analyze a plurality of loads supplied by the electric power system and to generate an estimated response of the loads. A fault analysis subsystem may analyze a plurality of factors relating to the fault and to determine a probability of the fault generating a fault induced delayed voltage recovery event. A control system may then implement a control strategy within a control window following the fault based on the probability of the fault generating a fault induced delayed voltage recovery event and the estimated response of the at least one load.

A PWM signal generation unit generates a PWM signal based on a driving voltage so that a midpoint of the longer period out of an H level period and an L level period in each PWM period matches a midpoint of the PWM period. FETs of a full bridge circuit (a driving circuit) are driven according to a PWM signal, and a driving current that corresponds to an A-phase is supplied to a stepping motor. A current detector detects a driving current flowing through an A-phase winding of the motor based on a voltage that is generated across a shunt resistor, at a fixed time point that is in each PWM period and in the H level or L level period that is at the center of the PWM period.

According to one example there is provided a method of adjusting a support structure. The method comprises obtaining a reference orientation of the support structure when the support structure is positioned in a reference position. The height of the support structure is adjusted to a predetermined position and the orientation of the support structure is adjusted such that the orientation of the support structure when in the predetermined position is substantially the same as the reference orientation.

An image forming apparatus and an image forming method are provided. The image forming apparatus includes a printing engine to form an image, a step motor to drive the printing engine, a driving circuit to provide a constant current to the step motor and sense a voltage corresponding to a magnitude of the constant current provided to the step motor, and a processor to calculate a temperature of the step motor based on the voltage sensed by the driving circuit during an excitation period of the step motor and control an operation of the image forming apparatus based on the calculated temperature.