Method for controlled motor speed reduction and mechanism for controlling motor speed reduction
A self-powered motor braking mechanism includes a dedicated power source sized for braking the respective motor and a dedicated braking circuitry configured to provide hybrid braking of the motor to a targeted stop. The motor braking circuitry is configured, in the event of a loss of primary power driving the motor, to provide a combination of two or more of dynamic braking, active braking and active position control to achieve zero speed of the motor by a target stopping time.
1 . A motor driving and braking assembly for controlling electrical driving of the motor and electrical braking of the motor to a targeted stop, the motor driving and braking assembly comprising:
a motor having two or more sensors and having two or more different windings;
a motor driving mechanism for electrical driving of the motor, the motor driving mechanism including a primary power source and primary control circuitry for controlling provision of power from the primary power source to the motor to drive the motor; and
a motor braking mechanism for electrical braking of the motor, the motor braking mechanism including a braking power source and a braking control circuitry for controlling provision of power from the braking power source to the motor to slow the motor, the braking power source being a battery and having a lower power capacity than the primary power source, and the braking control circuitry including
a braking control portion for analyzing position data from the two or more sensors of the motor,
a braking motor driving portion in communication with the braking control portion, the braking motor driving portion for directing power from the braking power source to the motor in a manner directed by the braking control portion for braking the motor in a closed loop circuit, and
a braking power conversion portion for switching power at two or more different windings of the motor and configured to enable shunting of the motor,
wherein the braking control portion is configured to direct the braking power conversion portion to cause shunting of the motor, wherein the braking control portion is configured to cause the braking power conversion portion to stop shunting and initiate closed loop braking of the motor including applying electrical power from the braking power source to the motor to further slow the motor via commutation after the shunting, and wherein the braking control portion is configured to achieve a zero speed of the motor within a target stopping time based on a calculated time duration of each of the shunting and the commutation, wherein the braking control portion includes a switching element disposable in series between the motor and power sources other than the braking power source, for preventing power transfer between the motor and the power sources other than the braking power source by electrically disconnecting the motor from the power sources other than the braking power source.
2 . The motor driving and braking assembly of claim 1 , wherein the braking control circuitry includes both a motor driver and a logic element.
3 . The motor driving and braking assembly of claim 2 , wherein the motor driver and logic element are integrated into a single circuit component.
4 . The motor driving and braking assembly of claim 1 , wherein the control circuitry of the motor driving mechanism includes
a primary control portion for analyzing positional data from the two or more sensors of the motor,
a primary motor driving portion in communication with the primary control portion, the primary motor driving portion for directing power from the primary power source to the motor in a manner directed by the primary control portion to drive the motor, and
a primary power conversion portion for switching power at respective windings of the two or more different windings of the motor.
5 . The motor driving and braking assembly of claim 1 , wherein the braking power source is a regenerable energy storage source, and wherein the braking control circuitry is configured to regenerate the power capacity of the braking power source upon at least active braking of the motor.
6 . The motor driving and braking assembly of claim 1 , wherein the braking power conversion portion includes one or more switching elements configured to cause the shunting of the motor upon direction of the braking control portion.
7 . The motor driving and braking assembly of claim 1 , wherein the braking power conversion portion is configured to cause the braking power conversion portion to stop shunting prior to the motor being brought to a zero speed.
8 . The motor driving and braking assembly of claim 1 , wherein the braking power source is at zero charge when the braking control portion directs the braking power conversion portion to cause shunting of the motor, and wherein the shunting of the motor dissipates energy from the motor and charges the braking power source to a non-zero charge.
9 . The motor braking mechanism of claim 1 , wherein the braking power circuitry is electrically disposed to be powered only by the braking power source.
10 . The motor driving and braking assembly of claim 1 , in combination with an outdoor power equipment machine, the motor being used to drive movement of an aspect of the outdoor power equipment machine.