A power tool is provided including a power supply interface having a first node and a second node, a power switch circuit, an input unit actuatable by a user, a controller configured to control the power switch circuit to regulate the supply of electric power, and a driver circuit disposed between the controller and the power switch circuit configured to receive control signals from the controller and drive the power switch circuit according. A no-volt prevention circuit is configured to enable a supply of power to at least one of the driver circuit or the controller when the input unit is actuated after the power supply interface is coupled to the power supply, but not when the input unit is actuated before to the power supply interface is coupled to the power supply.

A power tool is provided including a power supply interface having a first node and a second node, a power switch circuit, an input unit actuatable by a user, a controller configured to control the power switch circuit to regulate the supply of electric power, and a driver circuit disposed between the controller and the power switch circuit configured to receive control signals from the controller and drive the power switch circuit according. A no-volt prevention circuit is configured to enable a supply of power to at least one of the driver circuit or the controller when the input unit is actuated after the power supply interface is coupled to the power supply, but not when the input unit is actuated before to the power supply interface is coupled to the power supply.

A power tool including a power supply interface, a motor control circuit configured to regulate supply of power from the power supply interface to a motor, and an input unit actuatable by a user. A no-volt prevention circuit receives a first voltage signal from the power supply interface and a second voltage signal from the input unit. The no-volt protection circuit includes a main semiconductor switch arranged on a current path from the power supply interface to at least one component of the motor control circuit, and a resistor-capacitor circuit to turn the main semiconductor switch ON when the input unit is actuated after the power supply interface is coupled to the power supply, but not when the input unit is actuated before to the power supply interface is coupled to the power supply.

A motor driving circuit and a motor component are provided. The motor driving circuit includes a bidirectional alternating current switch connected in series with a motor across two terminals of an external alternating current power supply, where the bidirectional alternating current switch is connected between a first node and a second node; a rectifying circuit; a magnetic sensor, configured to detect a magnetic field of a rotor and output a corresponding magnetic inductive signal; a first voltage drop circuit and a second voltage drop circuit connected in series between the first input terminal of the rectifying circuit and the first node, where there is a third node between the first voltage drop circuit and the second voltage drop circuit, and the first voltage drop circuit is connected between the first node and the third node; a switch circuit connected between the third node and a control terminal of the bidirectional alternating current switch, where the switch circuit includes a first terminal, a second terminal, a control terminal and a switch arranged between the first terminal and the second terminal; and a switch control circuit connected between the control terminal of the switch circuit and an output terminal of the magnetic sensor.

A power tool includes a motor, a power circuit coupled to the motor, and a speed sensor coupled to the motor. The power circuit provides power to the motor. The speed sensor detects a position of the motor. The power tool also includes an electronic processor coupled to the motor and the speed sensor. The electronic processor is configured to receive an output signal from the speed sensor indicative of a measured speed of the motor at a first time, determine a cumulative value based on the measured speed of the motor, and interrupt power from the power circuit to the motor when the cumulative value exceeds an accumulator threshold.

An electrodynamic braking device for a universal motor includes a field winding configured to be fed from a grid during a braking operation, and an armature that is configured to be directly short-circuited. A braking process is performed by means of control electronics. Good braking is achieved with relatively low brush wear. Such an electrodynamic braking device can be used effectively for a power tool.

An electrodynamic braking device for a universal motor includes a field winding configured to be fed from a grid during a braking operation, and an armature that is configured to be directly short-circuited. A braking process is performed by means of control electronics. Good braking is achieved with relatively low brush wear. Such an electrodynamic braking device can be used effectively for a power tool.

A predictive current control method for a six-phase induction motor (6PIM) includes initializing a six-phase inverter at a present switching state, measuring a stator current and a rotor speed, transforming the stator current to and xy orthogonal frame, estimating a pair of currents in and xy frame based upon the measured and an estimated rotor speed, and calculating a future stator current for a future control sample of the inverter. The method further includes selecting four voltage vectors (VV) from and xy frames, implementing a cost function to calculate an error between the predicted future and a reference stator current, calculating a plurality of cost function results of each of the four VV, identifying a future VV that provides a minimum cost function results for the future control sample, saving the future VV to be used as an input to the lookup table for the next control sample and controlling the 6PIM by applying the future control sample as the switching state of the inverter.

A motor assembly for slowing down falling speed of a stage light fixture on power failure includes a motor driver, an automatic transfer switch, a capacitive load, and an alternating current motor. In the case that the automatic transfer switch is energized, windings of the alternating current motor are kept connected to the motor driver, and in the case that the automatic transfer switch is deenergized, the windings of the alternating current motor are switched to be connected to the capacitive loads. The motor assembly according to the present disclosure can reduce the falling speed of the stage light fixture in case of the power failure.

A predictive current control method for a six-phase induction motor (6PIM) includes initializing a six-phase inverter at a present switching state, measuring a stator current and a rotor speed, transforming the stator current to and xy orthogonal frame, estimating a pair of currents in and xy frame based upon the measured and an estimated rotor speed, and calculating a future stator current for a future control sample of the inverter. The method further includes selecting four voltage vectors (VV) from and xy frames, implementing a cost function to calculate an error between the predicted future and a reference stator current, calculating a plurality of cost function results of each of the four VV, identifying a future VV that provides a minimum cost function results for the future control sample, saving the future VV to be used as an input to the lookup table for the next control sample and controlling the 6PIM by applying the future control sample as the switching state of the inverter.