Milwaukee Electric Tool Corporation

Michael Best & Friedrich Llp

Alexander Huber

Timothy Ryan Obermann

Anthony M Davis

Timothy J Bartlett

Douglas R Fieldbinder

Patrick Dennis Gallagher

Shuvam Gupta

Jonathan E Abbott

Gerry M Nagel

William F Chapman, Iii

Gareth J Mueckl

Carl B Westerby

Evan M Glanzer

John E Koller

Connor P Sprague

David W Siegler

Nicholas C Mantych

Alex R Kuhls

Austin Gaspar

Griffin M Steffy

My Uyen Nguyen

Gerald M Nagel

A power tool that includes a brushless motor, a power switching circuit, a current sensor, and an electronic controller. The power switching circuit provides a supply of power to the brushless motor. The current sensor is configured to sense a current of the brushless motor. The electronic controller is configured to receive a first signal indicative of current of the brushless motor, generate a current command, set a conduction angle of the brushless motor based on the current command, supply a PWM signal having a duty cycle to the brushless motor to increase current of the brushless motor, determine whether duty cycle equals a first threshold, maintain the duty cycle at the first threshold, modify the conduction angle to increase the current of the brushless DC motor, determine whether current equals a second threshold, and control the second conduction angle to maintain current at the second threshold.

Power tool including current-based field weakening

A power tool device including a housing, first and second battery pack terminals, at least one bulk capacitor, a pre-charge circuit, and a discharge circuit. The pre-charge circuit includes at least one resistance connected in series with the at least one bulk capacitor, and a pre-charge switch connected in series with the at least one resistance. The pre-charge switch is configured to selectively provide a conductive path to charge the at least one bulk capacitor. The discharge circuit includes a first switch and a second switch connected in series with the at least one bulk capacitor. The first switch and the second switch are configured to be turned on after the at least one bulk capacitor is charged to a DC bus voltage.

Controlling bulk capacitance charge in a power tool device

A method for automatic control switching for driving a sensorless motor of a power tool, the method including generating, using a signal generator, a high-frequency injection signal. The method includes coupling, using a coupling circuit, the high-frequency injection signal to an injection coil of the sensorless motor. The method includes decoupling, using a de-coupling circuit, a response to the high-frequency injection signal from a phase coil of the sensorless motor. The method includes determine a sensorless motor condition based upon the response of the injection coil to the high-frequency injection signal. The method includes driving, using a controller of the power tool, the sensorless motor based upon the sensorless motor condition.

Sensorless motor control for a power tool

Power tool devices described herein include a motor, an actuator configured to be actuated by a user, a plurality of power switching elements configured to drive the motor, a gate driver coupled to the plurality of power switching elements and configured to control the plurality of power switching elements, a first printed circuit board (PCB), an antenna, and a combined chip. The combined chip is located on the first PCB and is coupled to the actuator, the antenna, and the gate driver. The combined chip includes a memory and an electronic processor configured to determine that the actuator has been actuated, and provide, in response to determining that the actuator has been actuated, a signal to the gate driver, control the signal based on the motor position information, wirelessly transmit power tool device information to an external device, and wirelessly receive configuration information from the external device via the antenna.

Power tool with combined chip for wireless communications and power tool control

Apparatus and method for motor braking using selectively connectable resistance. The method includes controlling, using a motor controller of the power tool, a power switching network to drive a motor of the power tool in response to actuation of a user input and determining, using the motor controller, a variable tool characteristic. The method further includes determining, using the motor controller, that the user input is de-actuated. The method also includes controlling, using the motor controller, the power switching network to brake the motor when the variable tool characteristic satisfies the tool characteristic threshold and controlling, using the motor controller, a braking circuit to brake the motor when the variable tool characteristic does not satisfy the tool characteristic threshold. The braking circuit includes one or more resistive loads and is selectively coupled to the motor terminals of the motor.

Motor braking using selectively connectable resistance

Systems and methods described herein provide for controlling a conduction angle applied to a motor, such as a power tool motor. Operations for controlling the conduction angle includes receiving by a motor controller, a desired speed signal, and monitoring a speed of the power tool motor. The operation further includes a motor controller determining an error value between the desired speed signal and the monitored speed and determining a conduction angle signal based on the error value. The operation also includes the motor controller determining whether the conduction angle signal is greater than the error value and increasing a conduction angle of the power tool motor in response to the conduction angle signal being determined to be greater than the error value.

Power tool including conduction angle control

Bi-directional motor () for gas engine replacement device (). One embodiment provides a gas engine replacement device () including a housing (), a battery receptacle (), a motor (), a power take-off shaft () receiving torque from the motor (), a power switching network () configured to selectively provide power to the motor (), and an electronic processor () coupled to the power switching network (). The electronic processor () is configured to rotate the motor () in a first direction and receive an input to switch a rotation direction of the motor (). The electronic processor is also configured to control the power switching network () to stop the motor () and rotate the motor () in a second direction after controlling the power switching network () to stop the motor ().

Bi-directional motor for gas engine replacement device

A device, such as a power tool, configured to receive a battery pack that is operable to determine a type of battery pack that is attached to the device. When the battery pack is connected to the device, the device is configured to determine an impedance of the battery pack. Based on the determined impedance of the battery pack, the device is capable of detecting the particular type of battery pack that has been attached. In some embodiments, the device is configured to be controlled based on the type of battery pack that has been detected by the device.

Detecting battery pack type based on battery pack impedance

Gas-engine replacement devices described herein include a housing that includes battery receptacle configured to removably receive a battery pack, a motor located within the housing, a power take-off shaft receiving torque from the motor and protruding from a side of the housing, a power switching network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switching network and configured to receive a current measurement associated with the motor and control the power switching network according to one of a freewheeling mode or a synchronous rectification mode based on the current measurement.

Motor control for gas engine replacement device

Power tool devices described herein include a housing, a power source interface, a field effect transistor within the housing connected between the power source interface and a load of the power tool device, and an electronic processor coupled to the field effect transistor. The electronic processor is configured to control the field effect transistor to drive the load and measure a voltage at a terminal of the field effect transistor. The electronic processor is also configured to determine the current flowing through the field effect transistor based on the voltage without using a shunt resistor.

Current sensing in power tool devices using a field effect transistor

A gas engine replacement device includes a housing, a battery receptacle coupled to the housing to receive a battery pack, a motor within the housing, a power take-off shaft receiving torque from the motor and protruding from a side of the housing, a power switching network configured to provide power from the battery pack to the motor, and an electronic processor coupled to the power switching network and configured to control the power switching network to rotate the motor and to receive a command speed, determine whether the command speed is in an exclusion zone, set an output speed at the command speed responsive to the command speed being outside the exclusion zone, set the output speed to a speed outside the exclusion zone responsive to the command speed being in the exclusion zone, and control the power switching network to rotate the motor in accordance with the output speed.

Power tools described herein include a housing, a motor supported by the housing, a battery pack configured to provide electrical power to the power tool, a user input configured to provide an input signal corresponding to a target speed of the motor, a plurality of sensors supported by the housing and configured to generate sensor data indicative of an operational parameter of the power tool, and an electronic controller. The electronic controller includes an electronic processor and a memory. The memory includes a machine learning control program for execution by the electronic processor. The electronic controller is configured to receive the target speed, receive the sensor data, process the sensor data using the machine learning control program, generate, using the machine learning control program, an output based on the sensor data, the output including one or more field weakening parameters, and control the motor based on the generated output.

Growing community of inventors

Menomonee Falls, WI, United States of America

Alexander Huber