Abstract: An electric tool and a motor drive system are provided. The motor drive system includes a trigger switch, an electronic switch, and a switch control circuit connected between the trigger switch and the electronic switch. The trigger switch is connected in series to a power supply. The electronic switch is configured to control a motor to be powered on or powered off. The switch control circuit is configured to control the electronic switch based on a state of the trigger switch, wherein the electronic switch is delayed to be turned off after the trigger switch is turned off to control the motor to be powered off later than a time that the trigger switch is turned off.

Abstract: A circuit includes a first operating component, a second operating component and a starting time control circuit. The starting voltage of the first operating component is different from that of the second operating component, and the starting time control circuit is configured to regulate a starting time of the first operating component to be synchronous with that of the second operating component.

Abstract: A power tool and a motor drive circuit thereof are provided. The motor drive circuit includes an inverter, a controller and a current sensor. The inverter includes a plurality of semiconductor switches and configured to convert a voltage from a power supply into an alternating current for an electric motor. The controller is configured to output detecting signals and drive signals for the inverter. The current sensor is configured to sample a current flowing through the motor, the current comprising a plurality of driving current portions corresponding to the drive signals and a plurality of position detecting current portions corresponding to the detecting signals. The controller determines the drive signals at least based on the position detecting current portions of the current so as to control power modes of the semiconductor switches in the inverter in a starting stage of the motor.

Abstract: A motor drive system is provided, which includes an inverter coupled with two terminals of a power supply, where the inverter includes multiple semi-conductive switch elements and is configured to convert a voltage provided by the power supply to an alternating current to drive a motor; a microcontroller coupled with two terminals of the power supply, where the microcontroller has an operation mode and a sleep mode; and a switch body, of which two terminals are respectively coupled with two terminals of the microcontroller, where the switch body is configured to output a response signal to the microcontroller to switch the microcontroller from the operation mode to the sleep mode or from the sleep mode to the operation mode according to the response signal.

Abstract: A motor drive system is provided, which includes: an inverter including an upper-half bridge and a lower-half bridge, the upper-half bridge and the lower-half bridge each including at least two semi-conductive switch elements, where the inverter is configured to convert a voltage provided by a power supply to an alternating current to drive a motor; a microcontroller configured to output a drive signal to the alternately turn on each two of the at least two semi-conductive switch elements of the upper-half bridge and each two of the at least two semi-conductive switch elements of the lower-half bridge when the motor performs braking, whereby a motor winding and the turned-on semi-conductive switch elements form a circuit a capacitor configured to supply power to the microcontroller when the motor performs braking.

Abstract: A motor drive system is provided, which includes: an inverter coupled with two terminals of a power supply, where the inverter includes multiple semi-conductive switch elements and is configured to convert a voltage provided by the power supply to an alternating current to drive a motor; a microcontroller configured to output a drive signal to control an power mode of the semi-conductive switch elements in the inverter; and a rheostat coupled with the microcontroller and configured to provide an input signal to the microcontroller by sliding, where the microcontroller outputs a brake signal to the inverter to control the motor to stop operating when the input signal meets a predetermined condition, and the microcontroller is powered off when the motor stops rotating.

Abstract: A motor control system controls power supplying of a motor. The motor control system is configured to control the motor be excited in advance of a zero crossing of a back electromotive force by an advance angle, and the advance angle gradually increases from an acceleration mode to a constant speed operating mode after the motor is started. The motor control system is further configured to control the motor to be excited within a conduction angle, and the conduction angle gradually reduces to a pre-determined value from the acceleration mode to the constant speed operating mode after the motor is started.

Abstract: A motor control system includes a drive controller and an inverter having two half bridges. When an excitation voltage for a motor is inverted or the motor is freewheeled, the drive controller turns off one semiconductor switch and turns on the other semiconductor switch after delaying for a delay angle in same half-bridge.

Abstract: A circuit includes a first operating component, a second operating component and a starting time control circuit. The starting voltage of the first operating component is different from that of the second operating component, and the starting time control circuit is configured to regulate a starting time of the first operating component to be synchronous with that of the second operating component.

Abstract: An air flow regulating device includes a housing, an air supply unit and a circuit board which are arranged inside the housing. The air supply unit includes an impeller and a single-phase permanent magnet brushless motor configured to drive the impeller. The single-phase permanent magnet brushless motor includes a stator and a rotor which can rotate relative to the stator. The stator includes a stator core and a single-phase winding wound around the stator core. The rotor includes a shaft and a permanent magnet fixed to the shaft. Numbers of magnetic poles of the stator and the rotor are the same and not greater than six. An outer diameter of the stator core is less than 35 mm and/or an axial thickness of the stator core is between 10 mm and 20 mm.

Abstract: A hair dryer includes a housing, and a heating unit, an air supply unit and a circuit board which are arranged inside the housing. The air supply unit includes an impeller and a single-phase direct current brushless motor for driving the impeller. The single-phase direct current brushless motor includes a stator and a rotor which is rotatable relative to the stator. The stator includes a stator core and a single-phase winding wound on the stator core. The rotor includes a shaft and a permanent magnet fixed on the shaft. A power supply terminal for connecting an external power supply and an inverter for providing an alternating current to the single-phase winding are arranged on the circuit board. An input voltage of the inverter is no lower than an input voltage of the power supply terminal.

Abstract: A power tool is provided. The power tool includes a housing, a working head extended from the housing, a brushless direct current motor configured to drive the working head, a battery, an inverter and a controller. The inverter includes a plurality of semiconductor switches and configured to convert a power from the battery into an alternating current power which is coupled to the brushless direct current motor. The controller is configured to output drive signals to control the semiconductor switches of the inverter based on a magnetic field position of the rotor obtained in a sensorless way.

Abstract: An electric tool and a motor drive system are provided. The motor drive system includes a trigger switch, an electronic switch, and a switch control circuit connected between the trigger switch and the electronic switch. The trigger switch is connected in series to a power supply. The electronic switch is configured to control a motor to be powered on or powered off. The switch control circuit is configured to control the electronic switch based on a state of the trigger switch, wherein the electronic switch is delayed to be turned off after the trigger switch is turned off to control the motor to be powered off later than a time that the trigger switch is turned off.

Abstract: A power tool and a motor drive circuit thereof are provided. The motor drive circuit includes an inverter, a controller and a current sensor. The inverter includes a plurality of semiconductor switches and configured to convert a voltage from a power supply into an alternating current for an electric motor. The controller is configured to output detecting signals and drive signals for the inverter. The current sensor is configured to sample a current flowing through the motor, the current comprising a plurality of driving current portions corresponding to the drive signals and a plurality of position detecting current portions corresponding to the detecting signals. The controller determines the drive signals at least based on the position detecting current portions of the current so as to control power modes of the semiconductor switches in the inverter in a starting stage of the motor.