Provided is an easy-to-use electric tool with which braking force can be changed according to work conditions. When an operation switch 5 is turned off, a control unit 50 detects a rotation rate R1 of an electric motor 6. The control unit 50 stands by for a prescribed period, detects a rotation rate R2 of the electric motor 6, and calculates the difference between the rotation rates R1, R2 (R=R1−R2). Since the rotation rate difference R corresponds to the rate of change in rotation rate with time during deceleration of the electric motor 6 and is smaller the larger the moment of inertia of the attached rotary tool, the control unit 50 can determine the moment of inertia of the rotary tool on the basis of the rotation rate difference R. The control unit 50 sets the braking force according to the moment of inertia and performs braking.

Provided is an easy-to-use electric tool with which braking force can be changed according to work conditions. When an operation switch 5 is turned off, a control unit 50 detects a rotation rate R1 of an electric motor 6. The control unit 50 stands by for a prescribed period, detects a rotation rate R2 of the electric motor 6, and calculates the difference between the rotation rates R1, R2 (R=R1−R2). Since the rotation rate difference R corresponds to the rate of change in rotation rate with time during deceleration of the electric motor 6 and is smaller the larger the moment of inertia of the attached rotary tool, the control unit 50 can determine the moment of inertia of the rotary tool on the basis of the rotation rate difference R. The control unit 50 sets the braking force according to the moment of inertia and performs braking.

An object of the present invention is to control driving force and braking force of a motor while considering an SOC of a battery. A control device controlling a rotating electric machine including windings of a plurality of independent system. The rotating electric machine is controlled in: a first mode in which an AC current is energized to the windings of the plurality of systems to generate torque such that a combined magnetic field generated in the windings is greater than or equal to a predetermined value; and a second mode in which the AC current having a phase difference different from that in the first mode is energized to the windings of the plurality of systems, the combined magnetic field generated in the windings is made smaller than the predetermined value, and current greater than or equal to that in the first mode flows.

Systems and methods are provided for braking a translator of a linear multiphase electromagnetic machine. The system detects a fault event, and in response to detecting the fault event, causes the translator to brake using an electromagnetic technique. Braking includes causing the translator to stop reciprocating, by applying a force opposing an axial motion, which may occur within one cycle, or over many cycles. The fault event may include, for example, a fault associated with an encoder, a controller, an electrical component, a communications link, a phase, or a subsystem. The system includes a power electronics system configured to apply current to the phases. The system may use position information, current information, operating parameters, or a combination thereof to brake. Alternatively, the system need not use position information, current information, and operating parameters, and may brake the translator independent of such information.

Systems and methods are provided for braking a translator of a linear multiphase electromagnetic machine. The system detects a fault event, and in response to detecting the fault event, causes the translator to brake using an electromagnetic technique. Braking includes causing the translator to stop reciprocating, by applying a force opposing an axial motion, which may occur within one cycle, or over many cycles. The fault event may include, for example, a fault associated with an encoder, a controller, an electrical component, a communications link, a phase, or a subsystem. The system includes a power electronics system configured to apply current to the phases. The system may use position information, current information, operating parameters, or a combination thereof to brake. Alternatively, the system need not use position information, current information, and operating parameters, and may brake the translator independent of such information.

A power supply device includes a storage battery; a capacitor unit having first and second capacitor; a three phase power converter, connected in parallel with the storage battery, each phase having first to fourth switching elements in series; three connection terminals electrically connectable to a three-phase AC charger; and a control unit, in a case where the three connection terminals and the three-phase AC charger are electrically connected between the first switching elements and the second switching elements for the respective three phases in the three-level inverter, before the storage battery is charged by means of the three-phase AC charger, charging the first capacitor with use of the storage battery and setting voltage of the second capacitor to 0 V.

An inverter device includes a motor, a power supply that supplies the motor with electric current, an inverter that, during regenerative operation of the motor, performs switching between a first state in which regenerative current generated in the motor is returned to the motor again and a second state in which the regenerative current is supplied to the power supply, a first detector that detects a first condition electrically acting on the inverter, a second detector that detects a second condition electrically acting on the power supply, and a determiner that performs a first determination to perform switching between the first state and the second state, based on a detection result by the first detector or the second detector.

Braking a power tool motor based on a phase voltage of the motor. The power tool includes a motor and a power source providing operating power to the motor. A power switching network is between the power source and the motor to drive the motor. An actuator is operable to provide an input. An electronic controller is connected to the actuator and the power switching network. The electronic controller is configured to receive an indication related to initiating braking of the motor, control the power switching network to allow the motor to coast, monitor a phase voltage of the motor, determine whether the phase voltage of the motor is equal to or less than a phase voltage threshold, and control, in response to the phase voltage of the motor being equal to or less than the phase voltage threshold, the power switching network to brake the motor.

Braking a power tool motor based on a phase voltage of the motor. The power tool includes a motor and a power source providing operating power to the motor. A power switching network is between the power source and the motor to drive the motor. An actuator is operable to provide an input. An electronic controller is connected to the actuator and the power switching network. The electronic controller is configured to receive an indication related to initiating braking of the motor, control the power switching network to allow the motor to coast, monitor a phase voltage of the motor, determine whether the phase voltage of the motor is equal to or less than a phase voltage threshold, and control, in response to the phase voltage of the motor being equal to or less than the phase voltage threshold, the power switching network to brake the motor.

A drive device for a vehicle flap includes an electric motor (2) for driving the vehicle flap, and a supply switching circuit (3). The supply switching circuit (3) includes a first voltage source (9) for supplying current to the electric motor (2), a first electrical supply line (4) and a second electrical supply line (5). The first voltage source (9) is arranged between the first electrical supply line (4) and the second electrical supply line (5). The drive device also includes a control switching circuit (12) including a second voltage source (14) and a switching control device (13). The drive device includes a switching element (10) and a diode (11) connected between the first electrical supply line (4) and the second electrical supply line (5).