Patent ID: 11909345
Assignee: MILWAUKEE ELECTRIC TOOL CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B | IPC B  H

Claim 0:
1. A power tool comprising:
a battery pack;
a three-phase motor including three motor terminals;
a power switching network coupled between the battery pack and the motor, wherein the power switching network includes a first power switching element and a second power switching element;
a user input configured to be actuated to drive the motor;
a braking circuit including a resistor and a braking switching element connected to each motor terminal, wherein each braking switching element is configured to selectively connect a respective resistor to a respective motor terminal, and wherein the braking circuit is configured to selectively couple each motor terminal to one selected from the group consisting of ground and a terminal of the battery pack; and
a motor controller connected to the power switching network and the braking circuit and configured to:
control the power switching network to drive the motor in response to actuation of the user input,
determine a variable tool characteristic,
determine that the user input is de-actuated,
determine whether the variable tool characteristic satisfies a tool characteristic threshold in response to the user input being de-actuated,
when the variable tool characteristic satisfies the tool characteristic threshold:
control the power switching network to brake the motor,
enable the first power switching element to induce a freewheeling current to flow through the first power switching element, wherein the freewheeling current flows through a diode of the second power switching element, and
disable the first power switching element to provide the freewheeling current to the battery pack, and

control the braking circuit to brake the motor when the variable tool characteristic does not satisfy the tool characteristic threshold,

wherein the variable tool characteristic is a motor current and wherein the variable tool characteristic satisfies the tool characteristic threshold when the motor current is below a regenerative braking threshold.