Brushless D. C. motor and control assembly

• US 6,271,638 B1
• Filed: 12/18/1996
• Issued: 08/07/2001
• Est. Priority Date: 04/06/1992
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Erdman, David M., Tatman, Richard S., Yoder, Dale F., Molnar, David T.
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US08/769,610
• Time in Patent Office: 1,693 Days
• Field of Search: 318/254, 318/439, 318/138, 318/268, 318/75, 318/779, 388/825-827, 388/237-239, 310/62.B, 310/156, 310/162, 310/164, 310/179, 310/189, 310/191, 310/192, 310/216, 310/217, 310/254, 310/258
• US Class Current: 318/400.01
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25D 17/06 by forced circulation
• CPC Class Codes: F25D 2400/04 Refrigerators with a horizontal mullion
• CPC Class Codes: F25D 29/00 Arrangement or mounting of control or safety devices
• CPC Class Codes: H02K 1/2726 the rotor consisting of a single magnet or two or more axially juxtaposed single magnets
• CPC Class Codes: H02K 1/2781 Magnets shaped to vary the mechanical air gap between the magnets and the stator
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 11/40 Structural association with grounding devices
• CPC Class Codes: H02K 15/03 having permanent magnets
• CPC Class Codes: H02K 21/18 having horse-shoe armature cores with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 2211/03 Machines characterised by circuit boards, e.g. pcb
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02K 3/524 for U-shaped, E-shaped or similarly shaped cores
• CPC Class Codes: H02K 5/02 Casings or enclosures characterised by the material thereof
• CPC Class Codes: H02K 5/08 Insulating casings
• CPC Class Codes: H02K 5/1672 radially supporting the rotary shaft at both ends of the rotor H02K5/1677 takes precedence
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132
• CPC Class Codes: H02P 6/08 Arrangements for controlling the speed or torque of a single motor H02P6/10, H02P6/28 take precedence
• CPC Class Codes: H02P 6/12 Monitoring commutation; Providing indication of commutation failure
• CPC Class Codes: Y10S 310/06 : Printed-circuit motors and components
• CPC Class Codes: Y10T 29/49012 : Rotor
• CPC Class Codes: Y10T 29/53143 : Motor or generator

Abstract

An energy efficient low-power integral electronically commutated fan motor and control circuit assembly mounted on a circuit board for use in refrigerators utilizing a Hall sensor to provide positional control signals for sequential energization of the windings with the Hall sensor energization being pulsed, and the motor stator windings energized only during a portion of the period, when rotational torque produced by the energization is greatest in order to reduce the power input to the assembly. Integrally molded multi-function components including the coil bobbin, ground pin, Hall sensor holder, motor bearing oil well covers, and assembly housing provide positioning, support, and securing assistance along with electrical and magnetic operative connections and positioning. A capacitively coupled bridge power supply is provided to further reduce power consumption, and the motor is protected under fault and stall conditions by a current limiting circuit and a timed retry circuit, and the rotor and stator are designed for adequate starting torque in a refrigerator. Power is supplied to the motor windings through a voltage dropping capacitor connected in series therewith.

Claims

1. A high-efficiency low-power integrated and unitary fan motor and control assembly suitable for use in refrigeration systems comprising an electronically commutated DC motor, a control and power circuit, and a substrate carrying a plurality of electronic components and interconnections of such circuit;

said electronically commutated motor including a stator core, a permanent magnet rotor, and at least one winding inductively coupled with said stator core;

a Hall sensor mounted on said substrate and forming part of said circuit, and positioned in magnetic coupling relationship with said permanent magnet rotor to sense rotation of said rotor;

said circuit including at least one DC power supply, and switching means to provide power to said at least one winding during a cycle of applied power defined by signals from said Hall device; and

said control circuit determining periods of reduced magnetic coupling between the rotor and stator during the cycle of applied power and inhibiting the supply of power to said at least one winding during the determined periods of reduced magnetic coupling, thereby to decrease the total amount of power supplied to the at least one winding and to increase the efficiency of the motor and control.

2. The motor and control assembly of claim 1 wherein said motor includes a bobbin that carries the at least one winding, and the assembly includes means that relatively position and interconnect said motor and electronic components, and said bobbin includes means that position and secure the bobbin on the substrate and that also provide electrical connections to said circuit.

3. The motor and control assembly of claim 2 wherein said means that secure said bobbin to said substrate includes electrical terminals to which said at least one winding is connected, and wherein said terminals pass through openings in the substrate and are soldered to said circuit board.

4. The motor and control assembly of claim 3 wherein said means that secure said bobbin to said substrate further includes at least one positioning support integral with said bobbin which extends outward from the bobbin in the same general direction as said terminals.

5. The motor and control assembly of claim 2 wherein the assembly further includes an insulating housing that positions and supports the motor and said substrate therewithin, and that electrically isolates said electronic components.

6. The motor and control assembly of claim 5 wherein said housing includes a hinged cover with latches thereon and also includes latch holders;

said cover being hinged over at least a portion of the portion and control and being latched in place thereby to enclose and isolate at least some of said electronic components.

7. The motor and control assembly of claim 3 wherein said motor includes a pair of oil well covers;

the substrate includes an oil well cover accommodating opening in a portion thereof;

the housing includes an oil well cover accommodating opening; and

the oil well cover includes a portion that passes through said portion of the substrate and is retained in said accommodating opening of the housing.

8. The motor and control assembly of claim 7 wherein:

said housing includes a number of resilient fingers extending about said, accommodating opening; and

wherein said resilient fingers grasp and secure said oil well cover in assembled relation therewith.

9. The motor and control assembly of claim 8 wherein the motor includes a second oil well cover, and wherein said oil well covers include portions that protrude from the housing and thereby provide means for suspending the assembly in the equipment with which it is to be used.

10. The motor and control assembly of claim 1 wherein:

said substrate comprise a circuit board that includes a grounding pin receiving aperture;

a grounding pin is mechanically and electrically secured to said stator core and to a run on the circuit board adjacent to said receiving aperture;

said grounding pin providing electrical grounding between said motor and the control and power circuit while also relatively positioning, securing and supporting said motor and circuit board.

11. The motor and control assembly of claim 1 wherein wherein the substrate includes a circuit board having a printed circuit thereon;

said printed circuit including a pattern of connectors for mating with an edge connector plug;

said assembly further including a housing having an opening adjacent said pattern of connectors, and also having means for positioning and guiding an edge connector plug into electrical contact with said pattern of connectors.

12. The motor and control assembly of claim 1 wherein said core includes an axially extending chamber integral therewith, a holder for said Hall sensor is positioned within said chamber, and said Hall sensor is positioned within said holder;

the Hall device holder including positioning means integral therewith which are secured to the substrate; and

electrical leads from the Hall sensor are soldered to circuitry on the substrate.

13. The motor and control assembly of claim 12 wherein the Hall device holder includes a shoulder integral therewith for contacting, spacing and supporting said stator core with respect to the substrate.

20. The motor and control assembly of claim 7 wherein said bobbin further includes at least one tapered camming member;

said housing includes a slot positioned to receive said at least one camming member; and

wherein said at least one camming member is configured to resiliently deform said housing until said at least one camming member enters said at least one slot thereby to detachably retain said bobbin and substrate in a predetermined position within said housing.

14. An electronically commutated integrated motor and control assembly particularly suitable for use in air moving applications comprising:

a stator core with at least one winding disposed thereon;

a permanent magnet rotor adapted to rotate about an axis of rotation in response to rotating magnetic fields in the stator core;

means for developing a position control signal indicative of the rotational position of said rotor;

said means for developing a position control signal including a sensor positioned adjacent the rotor for generating a control signal responsive to the rotational position of said rotor;

means for energizing said at least one winding during a cycle of applied power in a predetermined sequence in response to the position control signal; and

a control circuit for connecting power, through switching means, the control circuit to determine periods of lower rotational torque during the cycle of applied power, to provide power pulses to periodically energize said at least one winding during periods of generation of higher rotational torque, and for inhibiting the supply of power to the at least one winding during the determined periods of lower rotational torque thereby to provide increased operating efficiency.

15. The assembly of claim 14 wherein said switching means includes a timing circuit, and wherein said timing circuit includes an oscillator and divider circuit to provide timing signals for the operation of said switching means.

16. The assembly of claim 15 wherein said stator core includes a bore in which said rotor is rotatably supported, and the time duration of said power pulses is shorter than the time duration between said power pulses.

17. The assembly of claim 14 wherein said means for energizing said at least one winding in a predetermined sequence includes a capacitor in series with one line arranged for connection to a source of alternating current power.

18. The assembly of claim 17 wherein a full wave bridge rectifier circuit is connected across the lines arranged for connection to a source of power, and between said capacitor and said windings.

19. A method of controlling and operating a brushless DC motor in the form of a single phase motor having winding means in the form of two excitation windings that are sequentially energized during each complete cycle of applied power, said method including:

determining periods of reduced operating efficiency during each cycle of applied power, supplying power to the winding means primarily only during periods of greater operating efficiency during each cycle of applied power, and inhibiting the application of power to all of the winding means during at least part of that segment of each cycle of applied power when reduced operating efficiency would otherwise result; and

wherein the method further comprises energizing a first one of the windings at the beginning of the first half of an applied power cycle but not energizing the second one of the windings, and continuing to energize the first one of the windings during a period greater operating efficiency;

inhibiting energization of the first winding during at least part of the portion of the first half of the applied power cycle associated with reduced operating efficiency and continuing to inhibit energization of the second one of the windings until the end of the first half of the power cycle;

energizing the second winding at the beginning of the second half of the applied power cycle and continuing to energize the second winding during a period of greater operating efficiency;

inhibiting energization of the second winding during at least part of the portion of the second half of the applied power cycle associated with reduced operating efficiency; and

inhibiting energization of the first winding during the second half of the applied power cycle;

whereby no winding is energized during preselected portions of each applied power cycle.