Method and Apparatus for Electromagnetically Braking a Motor
First Claim
1. A motor assembly comprising:
- a rotor;
a stator having windings that are selectively energized by a first voltage from a high voltage bus to cause rotation of the rotor assembly;
a brake assembly having an electromagnet, a permanent magnet, and a moveable brake pad, wherein the brake assembly is adapted for releasing the rotor when the electromagnet is energized using a second voltage, and for braking the rotor when the electromagnet is de-energized; and
a controller having a DC-DC converter for converting the first voltage to the second voltage, the second voltage being lower than the first voltage;
wherein the controller includes an algorithm adapted for optimizing the second voltage as a function of a set of brake control parameters.
9 Assignments
0 Petitions
Accused Products
Abstract
An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller.
-
Citations
18 Claims
-
1. A motor assembly comprising:
-
a rotor; a stator having windings that are selectively energized by a first voltage from a high voltage bus to cause rotation of the rotor assembly; a brake assembly having an electromagnet, a permanent magnet, and a moveable brake pad, wherein the brake assembly is adapted for releasing the rotor when the electromagnet is energized using a second voltage, and for braking the rotor when the electromagnet is de-energized; and a controller having a DC-DC converter for converting the first voltage to the second voltage, the second voltage being lower than the first voltage; wherein the controller includes an algorithm adapted for optimizing the second voltage as a function of a set of brake control parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. An electromagnetic brake assembly for use with a motor assembly having a rotor and a stator operable for causing rotation of the rotor when the stator is energized, the electromagnetic brake assembly comprising:
-
an electromagnet; a permanent magnet; a moveable brake pad, wherein the electromagnetic brake assembly is adapted for releasing the brake pad from frictional engagement with the rotor when the electromagnet is energized using a second voltage, and for braking the rotor via friction engagement with the rotor when the electromagnet is de-energized; and a controller having a DC-DC converter operable for converting the first voltage to the second voltage at a voltage level lower than that of the first voltage; wherein the controller includes an algorithm adapted for optimizing the second voltage as a function of a set of brake control parameters. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A method for optimizing the efficiency of an electromagnetic brake assembly having a moveable brake pad adapted for selectively braking a rotor of a motor assembly, and having a housing containing an electromagnet and a permanent magnet, the method comprising:
-
detecting a set of brake control parameters; using a DC-DC converter to convert a first voltage from a high-voltage bus to a second voltage that is lower than the first voltage; applying the second voltage to the electromagnet to substantially cancel a magnetic flux of the permanent magnet, and to thereby allow the brake pad to move out of frictional engagement with the housing to release the rotor; discontinuing the second voltage to thereby allow the permanent magnet to move the brake pad into frictional engagement with the housing to brake the rotor; and automatically varying the second voltage as a function of a set of brake control parameters to thereby determine an optimal value of the second voltage. - View Dependent Claims (16, 17, 18)
-
Specification