Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2002-07-17
2003-11-11
Tanner, Harry B. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S228400
Reexamination Certificate
active
06644057
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a separate-type air conditioner that comprises a separate indoor unit and outdoor unit connected electrically.
BACKGROUND ART
As shown in
FIG. 13
, an electric circuit of a conventional air conditioner capable of cooling and heating comprising an indoor unit
1
, an outdoor unit
2
, and an indoor-outdoor connector cable
3
connecting them electrically. The indoor unit
1
comprises a main switch
4
, an indoor electronic controller
5
, an indoor fan motor
6
such as a transistor motor, and a louver motor
7
for driving upper and lower indoor blades. The outdoor unit
2
comprises an outdoor electronic controller
8
, a four-way valve
9
for switching a refrigerant flow path according to refrigerating and heating cycles, an outdoor fan motor
10
such as an induction motor, and a compressor
11
for compressing the refrigerant.
The operation of this conventional air conditioner will be described below.
The indoor unit
1
is connected to the commercial power supply
12
. When the main switch
4
on the indoor unit
1
is turned on, power is supplied to the indoor electronic controller
5
, which starts control operation and activates the indoor fan motor
6
and the louver motor
7
to start circulating indoor air through an indoor heat exchanger (not shown). Now if the user gives an operation start command, the indoor electronic controller
5
connects the outdoor unit
2
with the commercial power supply
12
by means of the main relay (not shown) to supply power to it. Receiving power from the commercial power supply
12
, the outdoor electronic controller
8
starts control operation: it applies control voltage to the compressor
11
to start its rotation and connects the outdoor fan motor
10
with the commercial power supply
12
to start sending outdoor air to an outdoor heat exchanger (not shown). When the commercial power supply
12
is not connected, the four-way valve
9
for switching the refrigerant flow path is positioned to pass the refrigerant to the cooling-cycle path under instructions from the outdoor electronic controller
8
. In this state, the air conditioner starts cooling operation.
Next, when the user specifies heating, the commercial power supply
12
is connected to the four-way valve
9
under instructions from the outdoor electronic controller
8
. This operation switches the refrigerant flow path to the heating-cycle side to make heating to be started. The outdoor fan motor
10
sends outdoor air to the outdoor heat exchanger, which extracts heat from the outdoor air into the refrigerant, which consequently vaporizes, is compressed by the compressor
11
, and is sent to the indoor heat exchanger.
In either case, the outdoor electronic controller
8
amplifies or attenuates the commercial power supply
12
in accordance with the operating frequency of the compressor
11
and applies the resulting voltage to the compressor
11
.
However, with the configuration of the conventional air conditioner, in which the output voltage to the compressor solely depends on the voltage of the commercial power supply, voltage variations in the commercial power supply will fluctuate the output voltage to the compressor, which may result in a failure to start the compressor. To eliminate this disadvantage, the output signal to the compressor should be set at a little larger value, which, however, may increase the vibration of the output unit at a start-up and during an operation. To deal with this situation, currently a vibration damping part such as Coal Tape, etc. is used in large quantities for the piping of the outdoor unit or a loop-like shape is given to the piping for vibration damping. However, this increases material costs and requires a large number of manhours during assembly, resulting in poor workability. Moreover, shifts in the operating point of the compressor will degrade the efficiency of the compressor, resulting in increased power consumption. Also, if the compressor is not pressure balanced during restarting, optimum voltage will not be applied. Therefore, a compressor with a dc motor may fail to restart due to insufficient starting torque.
An object of the present invention is to provide an air conditioner and its operation control method that will reduce the effect of voltage fluctuations in commercial power supply and ensure accurate compressor operation. Another object of the present invention is to provide an air conditioner and its operation control method that will improve the starting force of the compressor considering its starting load while reducing the effect of voltage fluctuations in the commercial power supply on the compressor.
DISCLOSURE OF THE INVENTION
To attain the above objects, a separate-type air conditioner according to the present invention contains a correction circuit of output voltage to a compressor in an outdoor unit. This voltage correction circuit keeps the output voltage to the outdoor unit constant (optimum) despite voltage fluctuations in a commercial power supply, making it possible to largely reduce the use of vibration damping material such as Coal Tape and simplify the shape of pipings while maintaining vibration of the outdoor unit at low levels, and thus providing the advantages of reduced material costs and improved working efficiency during assembly operations.
More particularly, the separate-type air conditioner according to the present invention connects the indoor and outdoor units electrically to each other by means of an indoor-outdoor connector cable and contains a correction circuit of the output voltage to the compressor in the outdoor unit to keep the output voltage to the outdoor unit constant by correcting fluctuations in the voltage of the commercial power supply. Since the correction circuit of the output voltage to the compressor keeps the output voltage to the outdoor unit constant, the vibration of the outdoor unit is maintained at low levels, resulting in reduced material costs and improved working efficiency during assembly operations.
The voltage correction circuit of the separate-type air conditioner according to the present invention comprises voltage detection means for detecting input voltage, reception means for receiving an input voltage signal outputted by the voltage detection means, a timer and an arithmetic circuit for averaging the input voltage signal received by the reception means within a specified time period, and determination means and the arithmetic circuit for voltage correction control in order for correcting and determining the output voltage to the compressor. Since the timer, arithmetic circuit, and determination means can keep the output voltage to the compressor constant, the vibration of the outdoor unit is maintained at low levels, resulting in reduced material costs and improved working efficiency during assembly operations.
The voltage correction circuit of the separate-type air conditioner according to the present invention comprises voltage detection means for detecting input voltage, reception means for receiving an input voltage signal outputted by the voltage detection means, and determination means for voltage correction control in order for correcting and determining the output voltage to the compressor based on the input voltage signal and by means of a data table. The use of the data table instead of the arithmetic circuit for obtaining optimum output voltage to the compressor from the input voltage signal has the effect of reducing capacity requirements of a micro computer and further reducing material costs.
The voltage correction circuit of the separate-type air conditioner according to the present invention comprises voltage detection means for detecting input voltage as well as determination means and an arithmetic circuit for voltage correction control in order fore correcting and determining the output voltage to the compressor by making corrections for loads, based on an outside air temperature detection signal outputted from outside air temperature detection means installed in the out
Nishizuka Toshiharu
Tabata Daisuke
Takeda Yuji
Matsushita Electric - Industrial Co., Ltd.
Parkhurst & Wendel L.L.P.
Tanner Harry B.
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