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 power tool is provided including a brushless electric motor, a switching arrangement having motor switches and interposed between the electric motor and a power supply, and a controller configured to control a switching operation of the motor switches for driving the electric motor and enforce a current limit on the current delivered to the electric motor. The controller receives a measure of current passing from the power supply to the switching arrangement and takes corrective action to reduce current delivered to the electric motor if the measured current exceeds the current limit. The controller is further configured to initiate a protective response if a number of time intervals in which the measured current exceeds the current limit exceeds a predetermined threshold.

A rotary electric machine control device for controlling driving of a rotary electric machine including a plurality of winding sets, includes: a plurality of drive circuits; and a plurality of control units, each of which includes: an individual current limit value calculation unit; a current limit value calculation unit; and a control signal calculation unit. The current limit value calculation unit switches between a current limit value sharing mode and a current limit value non-sharing mode. An electric power steering device includes: the rotary electric machine control device; the rotary electric machine that outputs an assist torque for assisting a steering operation of a steering wheel by a driver; and a power transmission unit that transmits a driving force of the rotary electric machine to a drive target.

Provided is a power steering apparatus capable of preventing or reducing a sudden change in a steering force. A power steering apparatus includes a steering mechanism configured to transmit a steering operation on a steering wheel to a turning target wheel, a first actuation portion and a second actuation portion configured to provide a steering force to the steering mechanism, and a controller configured to output a first driving instruction signal for controlling driving of the first actuation portion and a second driving instruction signal for controlling driving of the second actuation portion. The controller includes an output distribution control portion configured to change a ratio of the output of the first driving instruction signal and a ratio of the output of the second driving instruction signal. The output distribution control portion is configured to perform output distribution control of increasing the output ratio of one of the first driving instruction signal and the second driving instruction signal and reducing the output ratio of the other of the first driving instruction signal and the second driving instruction signal to a value greater than zero.

Drive circuits for parallel electric motors are provided. A drive circuit includes an inverter, at least one current sensor, and a DSP. The inverter is coupled to and configured to provide three phase power to a plurality of parallel electric motors. The at least one current sensor is coupled to the inverter and is configured to measure stator phase currents output by the inverter for driving the plurality of parallel electric motors. The DSP is coupled to the inverter and the at least one current sensor and is configured to receive the stator phase currents from the at least one current sensor, and generate at least one PWM signal for controlling the inverter based on the stator phase currents.

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.

Drive circuits for parallel electric motors are provided. A drive circuit includes an inverter, at least one current sensor, and a DSP. The inverter is coupled to and configured to provide three phase power to a plurality of parallel electric motors. The at least one current sensor is coupled to the inverter and is configured to measure stator phase currents output by the inverter for driving the plurality of parallel electric motors. The DSP is coupled to the inverter and the at least one current sensor and is configured to receive the stator phase currents from the at least one current sensor, and generate at least one PWM signal for controlling the inverter based on the stator phase currents.

A driving system for electric vehicles. The driving system may have two or more electric motors, each with voltage inputs, which are connected to the axles and tires of the vehicle. A variable input control may provide a signal that indicates its current operation position to a vehicle control unit. The vehicle control unit receives the information from the variable input control and determines how much power to send to each of the electric motors' voltage inputs.

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.

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.