Laundering apparatus, method of operating a laundry machine, control system for an electronically commutated motor, method of operating an electronically commutated motor, and circuit

• US 4,390,826 A
• Filed: 04/17/1980
• Issued: 06/28/1983
• Est. Priority Date: 06/24/1974
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Erdman, David M., Harms, Harold B.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Moose, Richard M.
• Application Number:
  US06/141,268
• Time in Patent Office: 1,167 Days
• Field of Search: 318/138, 318/254, 318/311, 318/345 R, 318/345 B, 318/439, 318/434, 318/317, 318/340, 318/331
• US Class Current: 318/400.17
• CPC Class Codes: D06F 2103/46 of the motor driving the drum
• CPC Class Codes: D06F 2105/46 Drum speed; Actuation of motors, e.g. starting or interrupting
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 37/304 Arrangements or adaptations of electric motors
• CPC Class Codes: F23N 2233/04 with variable speed
• CPC Class Codes: F23N 3/082 using electronic means
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: H02K 29/06 with position sensing devices H02K29/03 takes precedence
• CPC Class Codes: H02P 6/085 in a bridge configuration
• CPC Class Codes: H02P 6/14 Electronic commutators
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A method of operating a laundry machine. The machine has a pair of rotatable components and is driven by an electronically commutated motor having a stationary assembly with a plurality of winding stages and also having a rotatable assembly adapted to be selectively coupled to at least one of the rotatable components. In this method, a DC voltage for application to the motor is received, and a first control function is imposed on the operation of the machine to control the application of the DC voltage in accordance with a selected one of a plurality of first waveshapes so as to provide a resultant effective voltage to the motor. A second control function is imposed on the operation of the machine through the controlled application of the DC voltage to selectively set the maximum amplitude of the effective voltage, and the winding stages are commutated by applying the effective voltage thereto in sequence whereby the first and second control function jointly determine the angular velocity of the at least one rotatable component.

A laundering apparatus, a control system for an electronically commutated motor, a method of operating an electronically comutated motor, and a circuit are also disclosed.

Claims

1. A circuit for controlling the energization of an electrical load from an AC source comprising:

a pair of DC lines;

means for rectifying the AC output of the source to apply a DC voltage across said DC lines in the form of a full wave rectified sinusoidal signal;

means connected between said DC lines and the load for chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;

means responsive to an externally derived signal representative of the desired energization of the load for modulating the width of the pulses;

means responsive to current in said DC lines for modifying the externally derived signal to maintain the amplitude of the DC line current below a predetermined level;

means for detecting zero crossovers of the full wave rectified sinusoidal signal; and

means responsive to said detecting means for applying the pulses only during a predetermined time interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the time intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal, respectively;

whereby the load presents a high power factor to the AC source.

2. The circuit in accordance with claim 1 wherein the phase angle spacing is generally about 30°

.

3. The circuit in accordance with claim 1 wherein said chopping means comprises a switching transistor having its base connected to the output of said pulse width modulating means;

and

filter means connected between said transistor and the load;

whereby current flow in said DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

4. The circuit in accordance with claim 3 further comprising means responsive to the load current for modifying the externally derived signal to maintain the amplitude of the load current below a predetermined limit.

5. The circuit in accordance with claim 4 wherein the load is a DC motor, and further comprising:

means responsive to the energization of the motor for deriving a feedback signal;

means for comparing the feedback signal with the modified externally derived signal to provide an error signal; and

means for energizing the pulse width modulation means with the error signal.

6. The circuit in accordance with claim 5 wherein the feedback signal is derived from the effective voltage applied to the DC motor which has a rotatable assembly and a stationary assembly with a plurality of winding stages, and further comprising means responsive to the angular position of the rotatable assembly for deriving commutation signals;

and

electronic commutating means responsive to the commutation signals for applying the effective voltage to the winding stages in sequence.

7. A circuit for controlling the energization of an electronically commutated DC motor from an AC source, said DC motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the circuit comprising:

a pair of DC lines;

means for rectifying the AC output of the source to apply a DC voltage across the DC lines in the form of a full wave rectified sinusoidal signal;

means connected between the DC lines and the electronically commutated DC motor for chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;

means responsive to an externally derived signal representative of the desired energization of the electronically commutated DC motor for modulating the width of the pulses;

means responsive to current in the DC lines for modifying the externally derived signal to maintain the amplitude of the DC line current below a predetermined level; and

means connected to the pulse width modulating means for applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal, respectively;

whereby the electronically commutated DC motor presents a high power factor to the AC souce.

8. The circuit as set forth in claim 7 wherein the phase angle spacing is generally about 30°

.

9. The circuit as set forth in claim 7 wherein the chopping means comprises a switching transistor having its base connected to the output of the pulse width modulating means;

and

filter means connected between said transistor and the electronically commutated DC motor;

whereby current flow in said DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

10. The circuit as set forth in claim 9 further comprising means responsive to the load current of the electronically commutated motor for modifying the externally derived signal to maintain the amplitude of the load current below a predetermined limit.

11. The circuit as set forth in claim 10 further comprising:

means responsive to the energization of the motor for deriving a feedback signal;

means for comparing the feedback signal with the modified externally derived signal to provide an error signal; and

means for energizing the pulse width modulating means with the error signal.

12. A method of controlling the energization of an electrical load from an AC source comprising the steps of:

rectifying the AC output of the source to apply a DC voltage across a pair of DC lines in the form of a full wave rectified sinusoidal signal;

chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;

modulating the width of the pulses in response to an externally derived signal representative of the desired energization of the load;

modifying the externally derived signal in response to the current in the DC lines to maintain the amplitude of the DC line current below a predetermined level; and

applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal;

whereby the load presents a high power factor to the AC source.

13. A method as set forth in claim 12 wherein the phase angle spacing is generally about 30°

.

14. A method as set forth in claim 12 comprising the additional step of filtering the full wave rectified sinusoidal signal, whereby current flow in the DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

15. A method as set forth in claim 14 comprising the additional step of modifying the externally derived signal in response to the load current to maintain the amplitude of the load current below a predetermined limit.

16. A method of controlling the energization of an electronically commutated DC motor from an AC source, said DC motor having a rotatable assembly and a stationary assembly with a plurality of winding stages, the method comprising the steps of:

rectifying the AC output of the source to apply a DC voltage across a pair of DC lines in the form of a full wave rectified sinusoidal signal;

chopping the full wave rectified sinusoidal signal to provide pulses at a frequency which is high with respect to the frequency of the full wave rectified sinusoidal signal;

modulating the width of the pulses in response to an externally derived signal representative of the desired energization of the electronically commutated DC motor;

modifying the externally derived signal in response to the current in the DC lines to maintain the amplitude of the DC line current below a predetermined level; and

applying the pulses only during a predetermined interval in each half cycle of the full wave rectified sinusoidal signal, the initiating and terminating points of each of the time intervals being spaced substantially equal phase angles away from the initiating and terminating zero crossovers that define the corresponding half cycle of the full wave rectified sinusoidal signal;

whereby the electronically commutated DC motor presents a high power factor to the AC source.

17. A method as set forth in claim 16 wherein the phase angle spacing is generally about 30°

.

18. A method as set forth in claim 16 comprising the additional step of filtering the full wave rectified sinusoidal signal, whereby current flow in the DC lines during successive half cycles occurs in substantially rectangular blocks each having a substantially constant amplitude.

19. A method as set forth in claim 18 comprising the additional step of modifying the externally derived signal in response to the DC motor load current to maintain the amplitude of the load current below a predetermined limit.

20. A method as set forth in claim 19 comprising the additional steps of:

deriving a feedback signal in response to the energization of the motor; and

comparing the feedback signal with the modified externally derived signal to provide an error signal, the modulation of the width of the pulses being responsive to the error signal.

21. A method as set forth in claim 20 comprising the additional steps of deriving commutation signals in response to the angular position of the rotatable assembly and applying the effective voltage to the winding stages in sequence, the feedback signal being derived from the effective voltage applied to the DC motor.