Appliance AC power control apparatus

• US 5,804,999 A
• Filed: 08/09/1995
• Issued: 09/08/1998
• Est. Priority Date: 08/09/1995
• Status: Expired due to Fees

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Controls, Inc. (Johnson Controls International plc)
• Inventors: DeBoer, David P., Divjak, August A.
• Primary Examiner(s): RUBIN, MARGARET R
• Application Number:
  US08/512,814
• Time in Patent Office: 1,126 Days
• Field of Search: 327/110, 327/131, 327/137, 327/139, 327/126, 327/365, 327/561
• US Class Current: 327/110
• CPC Class Codes: H02M 5/2573 with control circuit
• CPC Class Codes: H03K 17/79 controlling bipolar semiconductor switches with more than two PN-junctions, or more than three electrodes, or more than one electrode connected to the same conductivity region
• CPC Class Codes: H03K 4/56 using a semiconductor device with negative feedback through a capacitor, e.g. Miller integrator

Abstract

An apparatus for controlling an electrical appliance coupled with an output terminus and configured to operate in response to an alternating input signal, such as input AC power. The apparatus comprises a reference signal generator for receiving the input signal and generating a reference signal (either V_RAMP or V_CONTROL) in response to the input signal, and a control circuit for controlling connection of the input signal to the output terminus in response to the reference signal and to a user-defined set-point signal. The control circuit is coupled with the reference signal generator and with a set-point terminal. The set-point terminal receives the set-point signal and the control circuit controls connection of the input signal with the output terminus in response to a predetermined relationship between the reference signal and the set-point signal; the apparatus is capable of generating a modified periodically interrupted AC power output based on an AC power input. In a preferred embodiment, the modified AC power output is asymmetrically periodic.

Claims

1. Apparatus for controlling an electrical appliance coupled with an output terminus of the apparatus and being configured to operate in response to an alternating input signal, the apparatus comprising:

a reference signal generator for receiving said input signal and generating a reference signal in response to said input signal; and

a controller for controlling connection of said input signal to said output terminus in response to said reference signal and to a user-defined set-point signal, said controller being coupled with said reference signal generator and with a set-point terminal for receiving said set-point signal, said controller interrupting connection of said input signal with said output terminus in response to a predetermined relationship between said reference signal and said set-point signal, said controller including;

a counter for generating a clock signal, said counter being coupled with said reference signal and generator and receiving said reference signal, said counter generating said clock signal in response to said reference signal;

a digital-to-analog convertor for converting digital signals to analog signals, said digital-to-analog convertor being coupled with said counter to receive said clock signal, said digital-to-analog convertor generating an asymmetrically periodized reference signal in response to said clock signal; and

a comparator for comparing said asymmetrically periodized reference signal and a user-defined set-point signal, said comparator being coupled with said digital-to-analog convertor and with a set-point terminal, said comparator receiving said asymmetrically periodized reference signal, said set-point terminal receiving said set-point signal and generating a control signal for interrupting said connection when said asymmetrically periodized reference signal and said set-point signal are in a predetermined relationship.

2. The apparatus of claim 1, wherein said controller further comprises an isolator for electrically isolating said comparator from said output terminus.

3. The apparatus of claim 2, wherein said isolator is an optically coupled isolator coupled with said comparator and with said output terminus, said optically coupled isolator being responsive to said output signal from said comparator to effect said interrupting of said connection of said input signal with said output terminus.

4. The apparatus of claim 1, wherein said controller further comprises an isolator for isolating said output terminus from said comparator, said isolator being coupled between said comparator and said output terminus, said isolator responding to said control signal to effect said connection interruption.

5. Apparatus for controlling an electrical appliance, said appliance being coupled with an apparatus output terminus and being configured to operate in response to an input signal, the apparatus comprising:

ramp signal generating means for receiving said input signal and generating a ramp reference signal in response to said input signal;

comparing means for comparing said ramp reference signal with a user-defined set-point signal, said comparing means being coupled with said ramp signal generator and with a set-point terminal, said set-point terminal receiving said set-point signal, said comparing means generating a control signal when said ramp reference signal and said set-point signal are in a predetermined relationship;

isolating means for electrically isolating said comparing means from said output terminus, said isolating means responding to said control signal to couple said input signal with said output terminus; and

a counter means for counting time intervals and a digital-to-analog converter means for converting digital signals to analog signals, said counter means and said digital-to-analog converting means being coupled together between said ramp signal generating means and said comparing means, said counter means being coupled with said ramp signal generating means and receiving said ramp reference signal from said ramp signal generating means, said digital-to-analog converting means being coupled with said counter means and receiving a clock signal from said counter means, said digital-to-analog converting means generating a stepped asymmetrically periodized reference signal in response to said clock signal, said comparing means receiving said asymmetrically periodized reference signal and comparing said asymmetrically periodized reference signal with said set-point signal to generate said control signal when said asymmetrically periodized reference signal and said set-point signal are in said predetermined relationship.

6. The apparatus of claim 5 wherein said isolating means is an optically coupled isolator.

7. The apparatus of claim 5 wherein said appliance is an electrical motor.

8. Apparatus for modifying input AC power for application to an appliance, comprising:

a ramp generator for generating a periodic ramp waveform, each period of said ramp waveform having a ramp portion linearly varying between a maximum voltage level and a minimum voltage level; and

an appliance controller coupled to said ramp generator for receiving said periodic ramp waveform, said appliance controller further coupled to an AC power supply for receiving input AC power and an input for a set-point voltage signal having a user-selectable voltage level, said appliance controller having a modified AC power output adaptable to be coupled to said appliance, said appliance controller generating a modified AC power waveform on said modified AC power output as a function of said ramp waveform and said setting voltage signal, said appliance controller produces a periodic stairstep control signal waveform as a function of said periodic ramp waveform, said controller outputting at least a portion of a periodic power waveform when the level of said stairstep control signal waveform is below the level of said set-point voltage signal, said appliance controller otherwise outputting no waveform on said modified AC power output.

9. The apparatus of claim 8, wherein said appliance controller compares the level of said ramp portion with the level of the set-point voltage signal, said appliance controller blocking said input AC power from being coupled to said AC modified power output until said ramp portion becomes the same as the level of the set-point voltage signal, at which time said input AC power is coupled to said modified AC power output.

10. The apparatus of claim 8, wherein said portion of said periodic power waveform is outputted by said appliance controller until said portion crosses 0 volts.

11. The apparatus of claim 8, wherein said controller generates said stairstep control waveform as a function of numbers of counts of cycles of said periodic ramp waveform.

12. The apparatus of claim 11, wherein the numbers of counts of cycles varies through a plurality of cycles of said stairstep control signal waveform, the variability of the numbers of counts of cycles creating an asymmetrically periodic stairstep control signal waveform.

13. The apparatus of claim 8, wherein said apparatus further comprises a rectifier receiving said input AC power and outputting a rectified AC signal, said ramp generator having an input receiving said rectified AC signal and generating said periodic ramp waveform as a function of said rectified AC signal.

14. The apparatus of claim 13, wherein said periodic ramp waveform has the same period as said rectified AC signal.

15. Apparatus for generating an asymmetrically periodic alternating waveform, comprising:

a sensor having an input for receiving a periodic waveform, said sensor sensing each cycle of said periodic waveform and outputting a pulse in response thereto;

counting circuitry having a clock input coupled to said sensor for receiving said pulse and having a plurality of count outputs, signals appearing on preselected ones of said count outputs as a function of the count of said pulses;

a stairstep signal generator coupled to said count outputs and having a stairstep signal output, said stairstep signal generator generating an asymmetrically periodic stairstep signal which increases from a base level and having a plurality of levels, said stairstep signal changing levels as a function of change of preselected ones of said count output signals, said counting circuitry counting to a first number which causes said stairstep signal to increase to a first one of said plurality of levels before dropping to a base level, said counting circuitry then counting to a second number which causes said stairstep signal to increase from said base level to a second one of said plurality of levels which is different than said first one of said plurality of levels; and

a controller having an input coupled to said stairstep signal output and a second input for receiving a user-selectable set-point signal, said controller generating an alternating portion of said asymmetrically periodic alternating waveform when said set-point signal is in a predetermined mathematical relation to the level of said stairstep signal, said controller otherwise generating a constant portion of said asymmetrically alternating waveform.

16. The apparatus of claim 15, wherein said periodic waveform is a ramped waveform.

17. The apparatus of claim 15, wherein said controller receives as an input a symmetrically periodic alternating waveform, said controller generating said asymmetrically periodic alternating waveform as a function of said symmetrically periodic alternating waveform.

18. An apparatus for controlling an appliance operable from a source of alternating current, comprising:

a waveform generator for generating an asymmetrically periodized stairstep signal;

a comparator for comparing said asymmetrically periodized stairstep signal with a user-defined set-point signal and generating a trigger signal when said asymmetrically periodized stairstep signal and said user-defined set-point signal are in a predetermined relationship; and

a switching device for receiving said trigger signal and having a port for coupling to said source of alternating current,

said switching device supplying a periodically disable alternating current signal to said appliance in periods that vary in accordance with said asymmetrically periodized stairstep signal.

19. The apparatus of claim 18 wherein said waveform generator generates a stairstep waveform having a plurality of discrete amplitudes.

20. The apparatus of claim 18 wherein said waveform generator comprises a counter for generating a clock signal and a digital-to-analog convertor receptive of said clock signal for generating said asymmetrically periodized stairstep signal.

21. The apparatus of claim 20 further comprising a ramp generator coupled to said counter for supplying a variable control signal for controlling the period of said clock signal.

22. The apparatus of claim 18 wherein said appliance is selected from the group consisting of an electrical motor and an electric light.

23. The apparatus of claim 18 wherein said appliance is an alternating current motor.