Nanjing Chervon Industry Co., Ltd.

Nanjing Chevron Industry Co., Ltd.

Yanqing Xu

Dezhong Yang

Haishen Xu

Hongwei Wang

Guang Li

Xiubo Dai

Yufei Ren

Yongkang Wu

Zhen Xu

Wenqi Zhen

Xiaogang Ding

Zhongyan Hou

Tiantian Yin

Aihua Xie

Shuang Li

Yiwen Xia

A power tool includes a motor, a speed regulation mechanism, a driver circuit, and a control module. The motor includes a stator winding and a rotor. The speed regulation mechanism is at least used for setting a target rotational speed of the motor. The driver circuit is used for delivering electrical energy provided by a power supply device from a direct current bus to the motor, where the driver circuit includes multiple electronic switches connected between the power supply device and the motor. The control module is configured to calculate a voltage vector according to a measured rotational speed of the motor, a phase current of the stator winding, and the target rotational speed and overmodulate the voltage vector to output a pulse-width modulation (PWM) signal to the driver circuit. A per-unit value of an amplitude of the voltage vector ranges from 0 to 1.15.

Power tool

A power tool includes a motor, a power supply device, a driver circuit, a parameter acquisition module, and a controller. The motor includes a stator and a rotor. The motor is configured to generate a reluctance torque. The driver circuit is electrically connected to the motor to drive the motor. The parameter acquisition module is configured to acquire a current of the motor, a rotational speed of the motor, and a position of the rotor. The controller is configured to: according to at least one of the current of the motor, the rotational speed of the motor, or the position of the rotor, dynamically adjust a current applied to the stator so that an included angle between a stator flux linkage of the motor and a rotor flux linkage of the motor ranges from 90° to 135°.

A power tool includes a housing, an electric motor, a driver circuit, a speed detection device, and a control device. The driver circuit is electrically connected to the electric motor to drive the electric motor to operate. The speed detection device is configured to acquire a rotational speed of the electric motor. The control device is connected to the speed detection device and the driver circuit and outputs a control signal to the driver circuit to control rotation of the electric motor. The control device is configured to acquire the rotational speed of the electric motor when the electric motor is in a start-up stage, obtain a rotational speed variation of the electric motor within a preset time based on the rotational speed of the electric motor, and turn off the electric motor when the rotational speed variation is less than a rotational speed variation threshold.

Power tool and control method thereof

A power tool includes a functional element, a motor, a power supply module, a driver circuit, and a control module. The control module is electrically connected to the driver circuit and configured to output a control signal to the driver circuit to control the driver circuit. The control module is configured to: in the case where the power tool is in a first operation stage, control the driver circuit in a first control mode so that a voltage of the motor varies with a rotor position of the motor in a square wave; and in the case where the power tool is in a second operation stage, control the driver circuit in a second control mode so that the voltage of the motor varies with the rotor position of the motor in a sine wave or a saddle wave.

A power tool includes a motor, a power supply device, a driver circuit, a parameter acquisition module, and a controller. The motor includes a stator and a rotor. The motor is configured to generate a reluctance torque. The driver circuit is electrically connected to the motor to drive the motor. The parameter acquisition module is configured to acquire a current of the motor, a rotational speed of the motor, and a position of the rotor. The controller is configured to: according to at least one of the current of the motor, the rotational speed of the motor, or the position of the rotor, dynamically adjust a current applied to the stator so that an included angle between a stator flux linkage of the motor and a rotor flux linkage of the motor ranges from 90&#xb0; to 135&#xb0;.

A controller of a power tool is configured to, based on a sampled current of a motor of the power tool, output control signals that change with a change of a position of a rotor of the motor to control a drive circuit of the power tool such that an input voltage and/or a current of the motor changes approximately in a sine wave.

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Nanjing, China

Yanqing Xu