Method and apparatus for power loss detection and saving of operation settings in an appliance

• US 6,597,144 B2
• Filed: 06/20/2001
• Issued: 07/22/2003
• Est. Priority Date: 06/21/2000
• Status: Expired due to Fees

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Pearson, Steven L., Hansen, Scott L., Herman, Mark L., Fox, Marvin L.
• Primary Examiner(s): Leykin, Rita
• Application Number:
  US09/885,643
• Publication Number:
  US 20020008488A1
• Time in Patent Office: 762 Days
• Field of Search: 318/807, 318/808, 318/803, 318/599, 318/810, 318/812, 318/817
• US Class Current: 318/599
• CPC Class Codes: D06F 2103/44 Current or voltage
• CPC Class Codes: D06F 33/46 Control of the energy or water consumption
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: D06F 58/48 Control of the energy consumption
• 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 and apparatus for monitoring voltage input to an appliance, such as a dryer, sensing when power input to the appliance is lost. In addition, a controller in the appliance pulses relay coils controlling motors and/or heating devices within the appliance to conserve energy on a backup capacitor that supplies the control circuit of the appliance in the event of power loss. Further, a voltage sense circuit outputting a square wave effects monitoring of the input voltage to the appliance by outputting the square wave signal whose cycle period is monitored to determine power outage. The controller stores current operation settings at the time of power outage in a memory device and ensures proper storage through the extra energy conserved from the capacitor by the pulsing of the relay coils.

Claims

1. A method for monitoring power input to a device comprising:

monitoring a frequency of a signal on an incoming line to the device by monitoring an output signal of a voltage sensing circuit within the device, which receives an input from the incoming line, the output signal having a signal characteristic corresponding to a square wave signal and having a corresponding prescribed cycle period;

sensing variations in the frequency of the monitored signal from a prescribed frequency by detecting when a cycle period of the output signal varies from the prescribed cycle period by a predetermined amount; and

issuing a power loss signal when the cycle period of the output signal varies from the prescribed period by another predetermined amount.

2. A method according to claim 1, wherein the power loss signal indicates a detected loss of power input on the incoming line.

3. A method for monitoring power input to an appliance and storing current operation settings of the appliance when the power input is lost, the method comprising the steps of:

monitoring at least a voltage signal on an incoming line to the device;

sensing variations of a frequency of at least the monitored voltage signal from a prescribed frequency;

issuing a power loss signal when a variation of the frequency from the prescribed frequency exceeds a first predetermined amount; and

pulsing relay coils controlling power input to at least one of an electro-mechanical device and a heating device within the appliance at a predetermined duty cycle in response to the power loss signal in order to increase a discharge time of an electric charge on a capacitor connected to the input line and also connected to the relay coil; and

storing current operation settings of the appliance in a memory using the charge of the capacitor after a predetermined number of cycles of the monitored voltage signal.

4. The method according to claim 3, wherein the voltage signal is an alternating voltage.

5. The method according to claim 3, further comprising the steps of:

monitoring an output signal of a voltage sensing circuit within the device, which receives an input from the incoming line, the output signal having a signal characteristic with a corresponding prescribed period;

detecting when a cycle period of the output signal varies from the prescribed cycle period by a second predetermined amount, which correlates to the prescribed frequency exceeding the first predetermined amount; and

issuing the power loss signal when the cycle period of the output signal varies from the prescribed period by the second predetermined amount.

6. The method according to claim 5, wherein the prescribed frequency is 60 Hertz and the prescribed cycle period is 16.66 milliseconds.

7. The method according to claim 5, wherein the signal characteristic is a square wave signal.

8. The method according to claim 3, wherein the appliance is one of a clothes dryer, a clothes washing machine and a dish washing machine.

9. The method according to claim 3, wherein the electro-mechanical device is a motor.

10. An apparatus for monitoring power input to an appliance and saving current operation settings of the appliance in the event of a power input loss, comprising:

a power input line that supplies a power input to the appliance;

a power supply circuit that converts a voltage of the power input into at least first and second supply voltages;

a capacitor within the power supply circuit connected between the first supply voltage and a ground;

a voltage sensing circuit connected to the second supply voltage and outputting a sensing signal having a frequency that corresponds to a power input frequency of the power input line;

one or more relay coils that control power input from the power input line to at least one of an electro-mechanical device and heating device within the appliance;

a memory device configured to store current operation settings of the appliance; and

a controller that detects the frequency of the sensing signal, controls the relay coils and stores current operation settings of the appliance in the memory device, the controller pulsing the relay coils using an electric charge from the capacitor at a prescribed duty cycle and stores current operation settings of the appliance in the memory device after a predetermined number of cycles of the sensing signal by using the electric charge from the capacitor when the controller detects a change in the frequency of the sensing signal.

11. The apparatus of claim 10, wherein the prescribed duty cycle is less than 100%.

12. The apparatus of claim 11, wherein the prescribed duty cycle is 50%.

13. The apparatus of claim 10, wherein the memory device is an EEPROM.

14. The apparatus of claim 10, wherein the electro-mechanical device is a motor.

15. The apparatus of claim 10, wherein the sensing signal is a square wave signal having a normal cycle period of 16.66 milliseconds.

16. The apparatus of claim 10, wherein the controller is configured to drive the relay coils with a steady state voltage during normal operation;

and

the change in frequency of the sensing signal signifies a loss of power on the power input line and the controller is configured to respond to the change in frequency by switching from the steady state voltage to pulsing the relay coils at the prescribed duty cycle.

17. The apparatus of claim 10, wherein the capacitor is approximately 2200 μ

F.

18. The apparatus of claim 10, wherein the frequency change detected by the controller is an increase in a cycle period of the sensing signal.

19. An apparatus for monitoring power input from a power input line to an appliance and saving current operation settings of the appliance in the event of a power input loss, the apparatus comprising:

one or more relay coils configured to control the power input to at least one of an electro-mechanical device and heating device within the appliance at a prescribed duty cycle in response to a power loss signal sensed by a voltage sensing circuit in order to increase a discharge time of an electric charge on a capacitor connected to the power input line and also connected to the one or more relay coils; and

a memory device configured to store current operation settings of the appliance using the electric charge of the capacitor after a predetermined number of cycles of the sensing signal.

20. The apparatus of claim 19, further comprising a power supply circuit configured to convert a voltage of the power input into at least first and second supply voltages;

a voltage sensing supply circuit connected to the second supply voltage and outputting a sensing signal having a frequency that corresponds to a power input frequency of the power input line; and

a controller configured to detect the frequency of the sensing signal, control the relay coils and store current operation settings of the appliance in the memory device.

21. The apparatus of claim 19, wherein a controller pulses the relay coils using an electric charge from the capacitor at the prescribed duty cycle and the controller stores current operation settings of the appliance in the memory device after the predetermined number of cycles of the sensing signal by using the electric charge from the capacitor when the controller detects a change in the frequency of the sensing signal.