Electricity: electrical systems and devices – Safety and protection of systems and devices – Compressor protective circuits
Reexamination Certificate
1999-02-19
2001-01-30
Sherry, Michael J. (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
Compressor protective circuits
C361S023000, C361S078000
Reexamination Certificate
active
06181538
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a compressor control device for a refrigerator and a method thereof More particularly, it relates to a compressor control device for a refrigerator and a method thereof, which sense a momentary power failure.
2. Related Art
A refrigerator includes a converter for converting an alternating current (AC) power to a direct current (DC) power, a power-supply unit which receives the direct current power from the converter and converts the direct current power to first and second direct current voltages, and a controller which receives the first direct current voltage from the power-supply unit and determines an operation frequency of a compressor according to a refrigerating compartment condition and a freezing compartment condition and generates a control signal.
In operation, if a power voltage is suddenly turned off during a normal operation and is then turned on, a power applied to a compressor becomes reduced during a power failure duration, thereby lowering revolutions per minute (rpm) of the compressor. In other words, if a momentary power failure occurs, a power applied to a compressor becomes reduced during the power failure duration, thereby lowering revolutions per minute of the compressor.
For example, if the power failure is maintained during 500 milliseconds (msec), the compressor revolutions per minute (rpm) drops from 3600 rpm before the power failure to 2000 rpm. Under this condition, if the power is provided again to the compressor, overcurrent is applied to the compressor, so that the compressor may be damaged.
In more detail, the compressor nearly maintains a normal revolutions per minute by inertia during a short time period after the power failure, but quickly drops its revolutions per minute if the time period after the power failure continues. Accordingly, if the power is provided again under the condition that the compressor nearly maintains the normal revolutions per minute, the compressor is not damaged. However, if the power failure time extends beyond the short time period, the revolutions per minute of the compressor becomes considerably lower than the normal revolutions per minute. In this case, if the power is provided again to the compressor, overcurrent is applied to the compressor, thereby possibly causing the compressor to become damaged.
I have found that the aforementioned refrigerator cannot effectively protect the compressor when the power failure occurs. Efforts have been made to improve refrigerators. For example, there exists a Japanese Patent Unexamined Publication No. sho 56-113969, published on Sep. 8, 1981 (hereinafter Japanese Patent '969).
While Japanese Patent '969 provides advantages, I note that it fails to adequately provide a compressor control device for a refrigerator, and method thereof, which efficiently and conveniently protects the compressor without an unnecessary delay of a power-on time.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a compressor control device for a refrigerator and a method thereof that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.
It is an object of the present invention to provide a compressor control device for a refrigerator, and a method thereof, which sense a momentary power failure by comparing a set revolutions per minute with an operation revolutions per minute, and control an on/off operation of the compressor according to a compressor driving state after a power comeback, thereby protecting the compressor.
It is a further object of the present invention to provide a compressor control device for a refrigerator, and a method thereof, which sense a momentary power failure by comparing a set revolutions per minute with an operation revolutions per minute, and control an on/off operation of the compressor according to a compressor driving state during a power failure duration occurring due to a momentary power failure, thereby protecting the compressor.
To achieve the above objects and others, in a refrigerator including a converter for converting an alternating current power to a direct current power, an inverter for converting the direct current power to 3-phase alternating current power, and a compressor driven by the 3-phase alternating current power, a compressor control device for the refrigerator includes: a revolutions per minute sensing means for sensing an operation revolutions per minute of the compressor; and a control means which determines a momentary power failure by comparing the operation revolutions per minute sensed by the revolutions per minute sensing means with a set revolutions per minute, and controls an on/off operation of the compressor according to a compressor driving state after a power comeback or during a power failure duration when occurring a momentary power failure.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method for controlling a compressor of a refrigerator including a converter for converting an alternating current power to a direct current power, an inverter for converting the direct current power to 3-phase alternating current power, and a compressor driven by the 3-phase alternating current power, includes the steps of: (a) determining a momentary power failure by comparing an operation revolutions per minute of the compressor with a set revolutions per minute; (b) if the step (a) determines a momentary power failure, determining whether a power failure duration is beyond a first set time; (c) if the power failure duration is beyond the first set time in the step (b), turning off the compressor; and (d) if the power failure duration is below the first set time in the step (b), sensing a compressor driving state during a second set time, and turning on and off the compressor according to the sensed compressor driving state.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: a compressor receiving a first substance uncompressed and outputting said first substance compressed, said compressor being driven by a primary power; a sensing unit sensing revolutions per minute of said compressor; and a power controller detecting a difference between said revolutions per minute of said compressor and a predetermined quantity of revolutions per minute, said power controller performing one of supplying said primary power to said compressor and cutting off said primary power to said compressor according to said difference detected.
To achieve these and other objects in accordance with the principles ofthe present invention, as embodied and broadly described, the present invention provides a method controlling a compressor of a refrigerator including a converter converting an alternating current power to a direct current power, an inverter converting said direct current power to a three-phase alternating current power, and a compressor driven by said three-phase alternating current power, comprising: detecting a power failure by comparing revolutions per minute of said compressor with a predetermined quantity of revolutions per minute; determining when a duration of said power failure extends beyond a first predetermined quantity of time, when said power failure is detected; first cutting off power to said compressor, when said duration of said power failure extends beyond said first predetermined quantity of time; and second cutting off power to said compressor according to a compressor status sensed during a second predetermined quantity oftime, when said duration of said power failure does not extend beyond said first predetermined quantity of time.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method controlling a compresso
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
Sherry Michael J.
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