Pumps – Condition responsive control of pump drive motor – By control of electric or magnetic drive motor
Reexamination Certificate
2001-11-29
2003-03-04
Freay, Charles G. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
By control of electric or magnetic drive motor
C417S053000, C417S044100, C417S045000, C417S018000, C417S212000, C417S417000
Reexamination Certificate
active
06527519
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and a method for controlling a linear compressor, and in particular to an apparatus and a method for controlling a linear compressor which are capable of controlling precisely movements of the linear compressor by detecting accurately a load occurred in the linear compressor and varying a stroke voltage applied to the linear compressor.
2. Description of the Prior Art
Generally, a linear compressor compresses a refrigerant by performing a reciprocation linear motion of a piston with a magnet and a coil instead of a crank shaft.
The linear compressor will be described in detail with reference to accompanying FIG.
1
.
FIG. 1
is a block diagram illustrating a construction of an apparatus for controlling a linear compressor. The apparatus for controlling a linear compressor includes a voltage detecting unit
30
detecting a voltage applied to a linear compressor according to increase of a stroke in accordance with a stroke voltage, a current detecting unit
20
detecting a current outputted from the linear compressor
12
according to the increase of the stroke in accordance with the stroke voltage, a microcomputer
40
calculating a stroke from a voltage and a current detected from the voltage detecting unit
30
and the current detecting unit
20
, comparing the stroke with a stroke reference value and outputting a switching control signal according to the comparison result, and an electric circuit unit
10
applying a stroke voltage to the linear compressor
12
according to the switching control signal of the microcomputer
40
.
The electric circuit unit
10
includes a linear compressor
12
adjusting a refrigerating capacity by varying a stroke by adjusting a velocity of up and down motion of a piston, a triac Tr
1
intermitting a voltage of AC power applied to the linear compressor, and a current sensing resistance R
1
.
In the linear compressor
12
, because the piston moves up and down by a stroke voltage according to a stroke reference value set by a user, the stroke can be varied, and accordingly a refrigerating capacity can be adjusted.
The operation of the apparatus for controlling the linear compressor will be described.
First, when a user sets a request temperature, the microcomputer
40
inputs a switching control signal according to a stroke reference value set by a user to the triac Tr
1
of the electric circuit unit
10
.
The triac Tr
1
of the electric circuit unit
10
controls a voltage applied to the linear compressor
12
according to the switching control signal, the piston of the linear compressor
12
performs an up and down motion, the stroke is varied according to the up and down motion of the piston of the linear compressor
12
, accordingly the refrigerating capacity can be adjusted.
In more detail, when a turn-on cycle is enlarged according to the switching control signal inputted to the triac Tr
1
of the electric circuit unit
10
, the stroke voltage increases, accordingly the stroke is increased.
When the stroke is varied, a voltage and a current generated in the linear compressor
12
are respectively detected in the voltage detecting unit
30
and the current detecting unit
20
and inputted to the microcomputer
40
.
The microcomputer
40
calculates the stroke by using the inputted voltage and current, the stroke is compared with the stroke reference value, a switching control signal according to the comparison result is outputted.
In more detail, when the calculated stroke is smaller than the stroke reference value, the microcomputer
40
outputs a switching control signal for enlarging the on cycle of the triac Tr
1
, accordingly the stroke voltage applied to the linear compressor
12
is increased. When the calculated stroke is larger than the stroke reference value, a switching control signal for shortening an on cycle of the triac Tr
1
is outputted, accordingly a stroke voltage applied to the linear compressor is decreased.
Unlike the conventional compressor the linear compressor
12
performs a linear motion, because of the reason it does not require a crankshaft converting a rotation motion into a linear motion, accordingly the linear compressor
12
has a low resistance loss and high efficiency.
In addition, by varying the stroke voltage applied to the linear compressor, the linear compressor varies a compression ratio, accordingly the linear compressor can be used for variable refrigerating control such as a refrigerator or an air conditioner, etc.
In order to control the stroke of the linear compressor
12
, the microcomputer
40
measures a load as basic information of the compressor, in order to measure the load, an outer temperature or a temperature of a condenser is used.
However, when the temperature is sensed through the sensor, because an accurate temperature can not be detected, it is impossible to detect a load accurately, and because a delay occurs in the temperature sensing, the linear compressor can not be controlled accurately.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus and a method for controlling a linear compressor which are capable of detecting accurately a load having a non-linearity characteristics and controlling a linear compressor so as to operate in a safe region by inducing suction/discharge pressure difference.
It is another object of the present invention to provide an apparatus and a method for controlling a linear compressor which are capable of detecting accurately a stroke of the linear compressor by inducing a suction/discharge pressure difference with a work operation value calculated by multiplying a current by a size of displacement and integrating the product.
In order to achieve the above-mentioned objects, an apparatus for controlling a linear compressor in accordance with the present invention includes a linear compressor adjusting a refrigerating capacity by a stroke voltage according to a stroke reference value, a current detecting unit detecting a current applied to the linear compressor, a work operation unit generating a work operation signal by integrating a current detected from the current detecting unit, a suction/discharge pressure difference storing unit storing a suction/discharge pressure difference according to the work operation signal, a microcomputer outputting a switching control signal according to the work operation signal and displaying the suction/discharge pressure difference according to the work operation signal, and an electric circuit unit controlling the linear compressor in accordance with the switching control signal.
In order to achieve the above-mentioned objects, a method for controlling a linear compressor in accordance with an embodiment of the present invention includes outputting a switching control signal according to the stroke reference value when a user inputs a request early stroke reference value, applying a stroke voltage applied to the linear compressor according to the switching control signal, detecting a current applied to the linear compressor when the linear compressor operates in accordance with the stroke voltage, generating a work operation signal by integrating the detected current, displaying the load by detecting a suction/discharge pressure difference according to the work operation signal, and varying a duty ratio of the switching control signal controlling the motion of the linear compressor by comparing the inputted work operation signal with a previous work operation signal.
In order to achieve the above-mentioned objects, a method for controlling a linear compressor in accordance with another embodiment of the present invention includes an outputting a switching control signal according to the stroke reference value when a user inputs a request early stroke reference value, outputting a switching control signal according to the stroke reference value, applying a stroke voltage applied to the linear compressor according to the switching control signal, detecting a current and a voltage a
Hwang Yin Young
Kim Se Young
Kim Yang Gyu
Park Jin Koo
Park Joon Hyung
Freay Charles G.
LG Electronics Inc.
Rodriguez William H.
LandOfFree
Apparatus and method for controlling the operation of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for controlling the operation of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for controlling the operation of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3077953