Power tool with field-oriented controlled electronic clutch

Abstract

An electric tool comprises an electric motor, a first sensor configured to monitor an electrical property of the electric motor, and an electronic control unit. The electronic control unit is configured, based on sensor signals from the first sensor, to determine a quadrature-axis current and / or a longitudinal-axis current of the electric motor, to determine a rotational speed of the electric motor, to determine an estimated torque output based on (i) the quadrature-axis current and / or the longitudinal-axis current and (ii) the rotational speed, and to issue a command to brake the electric motor in response to the estimated torque output exceeding a threshold value.

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