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

Claim 5:
6. A method for braking a three-phase motor of a power tool comprising:
controlling, using a motor controller of the power tool, a power switching network to drive the motor of the power tool in response to actuation of a user input, wherein the power switching network includes a first power switching element and a second power switching element;
determining, using the motor controller, a variable tool characteristic;
determining, using the motor controller, that the user input is de-actuated;
determining, using the motor controller, whether the variable tool characteristic satisfies a tool characteristic threshold in response to the user input being de-actuated;
in response to the variable tool characteristic satisfying the tool characteristic threshold:
controlling, using the motor controller, the power switching network to brake the motor,
enabling, using the motor controller, 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 switching element, and
disabling, using the motor controller, the first power switching element to provide the freewheeling current to a battery pack connected to the power tool; and

controlling, using the motor controller, a braking circuit to brake the motor in response to the variable tool characteristic not satisfying the tool characteristic threshold, the braking circuit including a respective resistor and a respective braking switching element connected to a respective terminal of the motor, and wherein each respective braking switching element is configured to selectively couple the respective resistor to the respective terminal of the motor,
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.