A method for calibrating a motor is provided. The method includes defining a reference speed for operating the motor; operating the motor until a first operating point at which the motor reaches the reference speed; measuring a first current of the motor and an angular acceleration associated with the first current at the first operating point; operating the motor until a second operating point at which the motor reaches the reference speed; measuring a second current of the motor at the second operating point; and estimating a calibration coefficient for calibrating the motor based at least on the first current, the second current, and the angular acceleration associated with the first current.

A rotating electric machine control device has an electronic control unit, or an ECU that controls driving of a motor having motor windings, and includes mutually-communicable plural control units. The control unit includes a basic instruction calculation unit, a field-weakening calculation unit, and a current control calculation unit and a PWM (pulse width modulation) output unit. The current control calculation unit and the PWM output unit generate a PWM signal based on d-axis current instruction values and q-axis current instruction values that are calculated based on basic current instruction values and field-weakening d-axis current instruction value. At least a part of the instruction values used for generation of the PWM signal is shared by the plural control units.

A motor apparatus includes a motor body, a circuit board, a driver, and a voice detector. The circuit board, which is connected to the motor body, supplies driving electric power to the motor body. The driver, which is mounted on the circuit board, converts power source electric power to the driving electric power. The voice detector, which is mounted on the circuit board, detects a voice.

Provided is a steering device which allows continued safe travel in the event of a fault during automatic steering control. The steering device is equipped with an electric drive device composed of a plurality of systems of electric motors and has an assist control function for assisting a driver in steering and an automatic steering control function for automatically controlling the steering angle of steered wheels on the basis of a steering angle instruction value. In the event a fault occurs in one of the electric motor systems of the electric drive device during control under automatic operation control, a controller in the steering device maintains automatic operation control S36 using the electric motor of a normally operating system not suffering from a fault, and then, upon shifting to assist control S21, the controller sets the output limit value of the electric motor to a fault-time output limit value, which is less than a normal-time output limit value set when all electric motor systems are operating normally.

The invention relates to a method for the closed-loop and open-loop control of two or more EC motors operated using a common converter, wherein for the purpose of setting the operating point of the EC motors, common open-loop or closed-loop control using at least one controller is provided, wherein a combination of at least two control options is provided and in this case a controlled variable regulates the voltage setting at the output of the converter such that the two or more EC motors follow an intended sequence of operating points in a stable manner.

A method for outputting constant air volume by a fan system including at least two brushless DC (BLDC) motors, the method including: storing a constant air volume control function Q=F (n, C) in a data processor, where Q indicates an air volume, n indicates a rotational speed of the BLDC motors, and C indicates an operating parameter of the BLDC motors; transmitting, by the data processor, identical speed signal commands to the BLDC motors, and allowing the BLDC motors to operate at equal or approximately equal rotational speeds; and feedbacking, by the BLDC motors, motor operating parameters C to the data processor, calculating, by the data processor, a motor speed n for outputting and maintaining a constant air volume, and transmitting the motor speed to the BLDC motors.

Provided is an electronic timepiece capable of suppressing variation in the drive speed of a rotor, and driving a motor at a constant speed. The electronic timepiece has a driver; a controller that controls the driver to the on state or the off state according to a current flowing through a coil of a motor; a detection signal output device configured to output a detection signal when the on time or the off time, which are the continuous time of the on state and off state of the driver, meets a specific condition; a reference signal output device that outputs a reference signal used as a reference of a drive speed of the motor; and a drive cycle adjuster that compares the output timing of the detection signal and the reference signal, shortens the drive cycle when the detection signal is output after the reference signal, and when the detection signal is output before the reference signal, lengthens the drive cycle of the motor.

A power tool comprising a housing, a motor, and a circuit board residing in the housing is provided. A rectifier that receives an alternating current and converts the alternating current to a direct current, a switching arrangement having a plurality of motor switches connected electrically between the rectifier and the motor, and a capacitor connected electrically between the rectifier and the switching arrangement, are mounted on a rear portion of a planar surface of the circuit board. A switching arrangement and at least one heat sink in thermal communication therewith are mounted on a front portion of the planar surface of the circuit board.

A vehicle driving apparatus includes an inverter which drives a permanent magnet motor. The inverter includes a three-phase bridge circuit including a plurality of switch elements, a drive circuit connected to the three-phase bridge circuit, a control circuit connected to the drive circuit, and an abnormality detecting unit which detects abnormality of the inverter. The drive circuit includes a three-phase-short-circuit-forming circuit which causes three phases of the permanent magnet motor to form short circuits, an abnormality accepting terminal which accepts an abnormality signal output from the abnormality detecting unit, and a check terminal which accepts an active check signal for causing the three-phase-short-circuit-forming circuit to perform three-phase short circuit control.

A driving device includes a connection switching unit that switches connection condition of a coil between Y connection and delta connection, an inverter, and a control device that controls a carrier frequency of the inverter. The carrier frequency is set at a first carrier frequency when the connection condition of the coil is the Y connection. The carrier frequency is set at a second carrier frequency when the connection condition of the coil is the delta connection.