FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
AIR CONDITIONER
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Field
[0001] The present disclosure relates to an air
5 conditioner.
Background
[0002] When products are used, although it is desirable
to use the products under a stable power supply voltage,
10 there are still many regions overseas where the power
supply voltage is unstable. Therefore, an abnormal power
supply voltage may be applied to the product. By
installing a stabilizer, it is possible to stabilize the
power supply voltage and apply a stable voltage to the
15 products.
[0003] However, the stabilizer is sold separately from
the products, and a price of the stabilizer is different
from the price of the product. If the product has a
protective function equivalent to a protective function of
20 the stabilizer, it is not needed to purchase the stabilizer.
[0004] In a case where the product has the protective
function equivalent to the protective function of the
stabilizer, even if an overvoltage having an overvoltage
interruption value designed for the product in advance is
25 applied to the product, the product can interrupt the
overvoltage by a substrate and protect itself so that an
overvoltage having a value equal to or more than the
overvoltage interruption value is not applied.
[0005] Typically, an air conditioner that determines an
30 anomaly of a commercial power supply has been proposed (for
example, refer to Patent Literature 1).
Citation List
3
Patent Literature
[0006] Patent Literature 1: International Publication
Pamphlet No. WO 2008/146923
5 Summary of Invention
Problem to be solved by the Invention
[0007] In the related art, since application of a
voltage to a driving unit is interrupted via a
microcomputer in a case where an overvoltage is detected,
10 it takes relatively long time before the driving unit is
protected, and there is a possibility that a component
disposed on a substrate is destroyed by an abnormal voltage
before the driving unit is protected.
[0008] The present disclosure has been made in view of
15 the above, and an object of the present disclosure is to
obtain an air conditioner that shortens time from detection
of an overvoltage to interruption of application of the
overvoltage.
20 Means to Solve the Problem
[0009] In order to solve the above-described problems
and achieve the object, an air conditioner according to the
present disclosure includes an indoor unit and an outdoor
unit. The air conditioner according to the present
25 disclosure includes: a relay that is in one of a shortcircuit state or a released state according to a switching
signal to be supplied; a voltage detection circuit that
detects a voltage; and a relay switching circuit that
outputs a switching signal for causing the relay to be in
30 the released state in a case where a value of the voltage
detected by the voltage detection circuit is larger than a
predetermined first threshold, to the relay. The relay,
the voltage detection circuit, and the relay switching
4
circuit are disposed in the indoor unit or the outdoor unit.
Effects of the Invention
[0010] An air conditioner according to the present
5 disclosure achieves an effect for shortening time from
detection of an overvoltage to interruption of application
of the overvoltage
Brief Description of Drawings
10 [0011] FIG. 1 is a diagram illustrating a configuration
of an air conditioner according to a first embodiment.
FIG. 2 is a diagram illustrating a configuration of an
external protection relay switching circuit included in an
outdoor unit of the air conditioner according to the first
15 embodiment.
FIG. 3 is a flowchart illustrating a procedure of an
operation performed by the air conditioner according to the
first embodiment.
FIG. 4 is a diagram illustrating a configuration of an
20 air conditioner according to a second embodiment.
FIG. 5 is a flowchart illustrating a procedure of an
operation performed by the air conditioner according to the
second embodiment.
25 Description of Embodiments
[0012] Hereinafter, an air conditioner according to
embodiments will be described in detail with reference to
the drawings.
[0013] First Embodiment.
30 FIG. 1 is a diagram illustrating a configuration of an
air conditioner 1 according to a first embodiment. The air
conditioner 1 includes an indoor unit 2 and an outdoor unit
3. An input power supply 4 that is an AC power supply is
5
connected to the indoor unit 2 and the outdoor unit 3. In
FIG. 1, the input power supply 4 is also illustrated.
[0014] The indoor unit 2 includes a terminal block 21
connected to the outdoor unit 3, a diode 22 connected to
5 the terminal block 21, a first relay 23 connected to the
terminal block 21, and a serial communication circuit 24
connected to the terminal block 21. The first relay 23 has
a function for switching power transmission to the outdoor
unit 3 and serial communication between the indoor unit 2
10 and the outdoor unit 3. In a case where a state of the
first relay 23 is a state where the first relay 23 is
caused to transmit power to the outdoor unit 3, that is, in
a case where the state of the first relay 23 is a shortcircuit state, an AC voltage is applied to the outdoor unit
15 3.
[0015] The indoor unit 2 further includes a capacitor 25
connected to the diode 22, a wiring line 26 that connects
the diode 22 and the capacitor 25, and a medium voltage
detection circuit 27 connected to the wiring line 26.
20 [0016] The outdoor unit 3 includes a terminal block 31
connected to the indoor unit 2. The air conditioner 1
further includes wiring lines 5, 6, and 7 that connect the
terminal block 21 of the indoor unit 2 and the terminal
block 31 of the outdoor unit 3. The outdoor unit 3 further
25 includes a second relay 32 connected to the terminal block
31, a third relay 33 connected to the terminal block 31,
and a serial communication circuit 34 connected to the
third relay 33. The second relay 32 is in one of a shortcircuit state or a released state, in accordance with a
30 switching signal to be supplied. The third relay 33 has a
function for switching power reception from the indoor unit
2 and the serial communication between the indoor unit 2
and the outdoor unit 3. The state of the first relay 23 is
6
a state where the first relay 23 is caused to transmit
power to the outdoor unit 3 and a state of the third relay
33 is a state where the third relay 33 is caused to receive
power from the indoor unit 2, the AC voltage is applied to
5 the outdoor unit 3. That is, in a case where each of the
states of the first relay 23 and the third relay 33 is the
short-circuit state, the AC voltage is applied to the
inside of the outdoor unit 3.
[0017] The outdoor unit 3 further includes a power
10 supply voltage detection circuit 35 connected to the
terminal block 31 and a resistor 36 that connects the third
relay 33 and the power supply voltage detection circuit 35.
The power supply voltage detection circuit 35 is also
connected to the second relay 32. The outdoor unit 3
15 further includes an AC/DC converter 37 connected to the
terminal block 31, the second relay 32, the power supply
voltage detection circuit 35, and the resistor 36. The
AC/DC converter 37 has a function for converting the
supplied AC voltage into a DC voltage. In FIG. 1, the
20 AC/DC converter 37 is described as an “ACDC converter 37”.
AC is an abbreviation for Alternating Current, and DC is an
abbreviation for Direct Current. The AC/DC converter 37
includes four diodes 37a, 37b, 37c, and 37d.
[0018] The outdoor unit 3 further includes a capacitor
25 38 connected to the AC/DC converter 37 and an external
voltage detection circuit 39 that detects a voltage.
Specifically, the external voltage detection circuit 39
detects a voltage of the outdoor unit 3. The outdoor unit
3 further includes a DC/DC converter 40 connected to the
30 capacitor 38. The DC/DC converter 40 has a function for
converting a DC voltage having a certain value into a DC
voltage having another value. In FIG. 1, the DC/DC
converter 40 is described as a “DCDC converter 40”. The
7
outdoor unit 3 further includes an intelligent power module
41 connected to the AC/DC converter 37, the capacitor 38,
the external voltage detection circuit 39, and the DC/DC
converter 40. In FIG. 1, the intelligent power module 41
5 is described as an “IPM 41”. The IPM is an abbreviation
for Intelligent Power Module.
[0019] The outdoor unit 3 further includes an external
protection relay switching circuit 42 connected to the
external voltage detection circuit 39. The external
10 voltage detection circuit 39 outputs a voltage signal
indicating a detected voltage to the external protection
relay switching circuit 42. In a case where the value of
the voltage detected by the external voltage detection
circuit 39 is larger than a predetermined first threshold,
15 the external protection relay switching circuit 42 outputs
a switching signal for causing the second relay 32 to be
released, to the second relay 32.
[0020] Specifically, the external protection relay
switching circuit 42 receives the voltage signal output
20 from the external voltage detection circuit 39 and outputs
a short-circuit release signal for switching short-circuit
and release of the second relay 32, to the second relay 32,
on the basis of the received voltage signal. More
specifically, the short-circuit release signal is a signal
25 for causing the second relay 32 to be in the short-circuit
state or the released state. The second relay 32 receives
the short-circuit release signal output from the external
protection relay switching circuit 42 and is in one of the
short-circuit state or the released state according to the
30 received short-circuit release signal.
[0021] The outdoor unit 3 further includes a central
processing unit 43 that outputs a driving signal for
driving the external protection relay switching circuit 42
8
to the external protection relay switching circuit 42. In
FIG. 1, the central processing unit 43 is described as a
“CPU 43”. The CPU is an abbreviation for Central
Processing Unit.
5 [0022] FIG. 2 is a diagram illustrating a configuration
of the external protection relay switching circuit 42
included in the outdoor unit 3 of the air conditioner 1
according to the first embodiment. The external protection
relay switching circuit 42 includes a voltage comparator 51
10 connected to the external voltage detection circuit 39, a
switching element 52 that is connected to the voltage
comparator 51 and receives a signal from the voltage
comparator 51, and a relay 53 connected to the switching
element 52. In FIG. 2, the external voltage detection
15 circuit 39 is also illustrated.
[0023] The switching element 52 is turned on or off, in
accordance with the driving signal output from the central
processing unit 43. However, in a case where the voltage
comparator 51 determines that a voltage indicated by the
20 voltage signal output from the external voltage detection
circuit 39 is an overvoltage, the voltage comparator 51 is
turned on, and even if the driving signal output from the
central processing unit 43 is a signal that turns on the
switching element 52, the switching element 52 does not
25 receive the driving signal output from the central
processing unit 43 and is turned off.
[0024] Next, an operation of the air conditioner 1 in a
case where an anomaly of a power supply voltage occurs
after the voltage is applied from the input power supply 4
30 and activation is performed, will be described. FIG. 3 is
a flowchart illustrating a procedure of the operation
performed by the air conditioner 1 according to the first
embodiment. When the power supply voltage is applied, the
9
air conditioner 1 starts the operation, and at the time of
activation, the central processing unit 43 outputs a shortcircuit signal to the external protection relay switching
circuit 42 (S1). The short-circuit signal is a signal for
5 short-circuiting the second relay 32. The external
protection relay switching circuit 42 outputs the shortcircuit signal to the second relay 32 (S2). The second
relay 32 is short-circuited (S3). In FIG. 3, the central
processing unit is described as a “CPU”.
10 [0025] During the operation of the air conditioner 1,
the external protection relay switching circuit 42
determines whether or not the value of the voltage detected
by the external voltage detection circuit 39 is larger than
the first threshold (S4). The first threshold is a value
15 used to determine whether or not the voltage detected by
the external voltage detection circuit 39 is an overvoltage.
More specifically, in a case where the voltage detected by
the external voltage detection circuit 39 is the
overvoltage, the value of the voltage detected by the
20 external voltage detection circuit 39 is larger than the
first threshold.
[0026] In a case of determining that the value of the
voltage detected by the external voltage detection circuit
39 is larger than the first threshold (Yes in S4), the
25 external protection relay switching circuit 42 outputs a
release signal to the second relay 32 (S5). The second
relay 32 is in the released state according to the release
signal (S6). In a case of determining that the value of
the voltage detected by the external voltage detection
30 circuit 39 is equal to or less than the first threshold (No
in S4), the external protection relay switching circuit 42
performs the operation in step S4 again.
[0027] As described above, the outdoor unit 3 included
10
in the air conditioner 1 according to the first embodiment
includes the second relay 32 that is in one of the shortcircuit state or the released state according to the
switching signal to be supplied, the external voltage
5 detection circuit 39 that detects the voltage, and the
external protection relay switching circuit 42 that outputs
the switching signal for causing the second relay 32 to be
in the released state in a case where the value of the
voltage detected by the external voltage detection circuit
10 39 is larger than the predetermined first threshold, to the
second relay 32.
[0028] That is, in the first embodiment, the voltage
signal output from the external voltage detection circuit
39 is received by the external protection relay switching
15 circuit 42 that is hardware, without passing through a CPU
and a microcomputer, and the external protection relay
switching circuit 42 outputs the switching signal for
causing the second relay 32 to be in the released state in
a case where the value of the voltage detected by the
20 external voltage detection circuit 39 is larger than the
predetermined first threshold, to the second relay 32.
That is, in a case where the value of the detected voltage
is larger than the first threshold, the application of the
overvoltage to the outdoor unit 3 is interrupted.
25 [0029] Therefore, since the voltage signal output from
the external voltage detection circuit 39 is received by
the external protection relay switching circuit 42 that is
hardware without passing through the CPU and the
microcomputer, the air conditioner 1 can shorten time after
30 the detection of the overvoltage to the interruption of the
application of the overvoltage. As a result, in the air
conditioner 1, it is possible to prevent components of the
air conditioner 1 from being broken before the interruption
11
of the application of the overvoltage.
[0030] Second Embodiment.
FIG. 4 is a diagram illustrating a configuration of an
air conditioner 1A according to a second embodiment. The
5 air conditioner 1A includes an indoor unit 2A and an
outdoor unit 3A. The input power supply 4 that is the AC
power supply is connected to the indoor unit 2A and the
outdoor unit 3A. In FIG. 4, the input power supply 4 is
also illustrated.
10 [0031] The indoor unit 2A includes a terminal block 61
connected to the outdoor unit 3A, a diode 62 connected to
the terminal block 61, and a fourth relay 63 connected to
the terminal block 61. The diode 62 is also connected to
the fourth relay 63. The fourth relay 63 is in one of the
15 short-circuit state or the released state, in accordance
with the switching signal to be supplied. The indoor unit
2A further includes a serial communication circuit 64
connected to the terminal block 61, a capacitor 65
connected to the diode 62, a wiring line 66 that connects
20 the diode 62 and the capacitor 65, and a medium voltage
detection circuit 67 that is connected to the wiring line
66 and detects a voltage. The medium voltage detection
circuit 67 detects a voltage of the indoor unit 2A.
[0032] The indoor unit 2A further includes a medium
25 protection relay switching circuit 68 that outputs the
switching signal for causing the fourth relay 63 to be in
the released state in a case where a value of the voltage
detected by the medium voltage detection circuit 67 is
larger than the predetermined first threshold, to the
30 fourth relay 63. More specifically, the medium protection
relay switching circuit 68 outputs the short-circuit
release signal for switching the short-circuit and the
release of the fourth relay 63 to the fourth relay 63, on
12
the basis of the detection result obtained by the medium
voltage detection circuit 67. The short-circuit release
signal is a signal for causing the fourth relay 63 to be in
the short-circuit state or the released state. The fourth
5 relay 63 receives the short-circuit release signal output
from the medium protection relay switching circuit 68 and
is in one of the short-circuit state or the released state
according to the received short-circuit release signal.
[0033] The indoor unit 2A further includes a central
10 processing unit 69 that outputs a driving signal for
driving the medium protection relay switching circuit 68 to
the medium protection relay switching circuit 68. In FIG.
4, the central processing unit 69 is described as a “CPU
69”. The air conditioner 1A applies the AC voltage to the
15 outdoor unit 3A via the fourth relay 63.
[0034] The outdoor unit 3A includes a terminal block 71
connected to the indoor unit 2A. The air conditioner 1A
further includes wiring lines 5A, 6A, and 7A that connect
the terminal block 61 of the indoor unit 2A and the
20 terminal block 71 of the outdoor unit 3A. The outdoor unit
3A further includes a fifth relay 72, a resistor 73, and a
serial communication circuit 74. The fifth relay 72, the
resistor 73, and the serial communication circuit 74 are
connected to the terminal block 71. The resistor 73 is
25 connected to both of two ends of the fifth relay 72.
[0035] The outdoor unit 3A further includes an AC/DC
converter 75 connected to the terminal block 71, the fifth
relay 72, and the resistor 73. The AC/DC converter 75 has
a function for converting the supplied AC voltage into the
30 DC voltage. In FIG. 4, the AC/DC converter 75 is described
as an “ACDC converter 75”. The AC/DC converter 75 includes
four diodes 75a, 75b, 75c, and 75d.
[0036] The outdoor unit 3A further includes a capacitor
13
76 connected to the AC/DC converter 75, an external voltage
detection circuit 77 that detects a voltage of the
capacitor 76, and a DC/DC converter 78 connected to the
capacitor 76. The DC/DC converter 78 has a function for
5 converting a DC voltage having a certain value into a DC
voltage having another value. In FIG. 4, the DC/DC
converter 78 is described as a “DCDC converter 78”. The
outdoor unit 3A further includes an intelligent power
module 79 connected to the AC/DC converter 75, the
10 capacitor 76, the external voltage detection circuit 77,
and the DC/DC converter 78. In FIG. 4, the intelligent
power module 79 is described as an “IPM 79”.
[0037] A configuration of the medium protection relay
switching circuit 68 included in the indoor unit 2A of the
15 air conditioner 1A is the same as the configuration of the
external protection relay switching circuit 42 in the first
embodiment. That is, as illustrated in FIG. 2, the medium
protection relay switching circuit 68 includes the voltage
comparator 51, the switching element 52 that is connected
20 to the voltage comparator 51 and receives a signal from the
voltage comparator 51, and the relay 53 connected to the
switching element 52. Note that, in the second embodiment,
the external voltage detection circuit 39 in FIG. 2 is
replaced with the medium voltage detection circuit 67.
25 Therefore, in the second embodiment, the voltage comparator
51 is connected to the medium voltage detection circuit 67.
[0038] Next, an operation of the air conditioner 1A in a
case where an anomaly of a power supply voltage occurs
after the voltage is applied from the input power supply 4
30 and activation is performed, will be described. FIG. 5 is
a flowchart illustrating a procedure of the operation
performed by the air conditioner 1A according to the second
embodiment. When the power supply voltage is applied, the
14
air conditioner 1A starts the operation, and at the time of
activation, the central processing unit 69 outputs a shortcircuit signal to the medium protection relay switching
circuit 68 (S11). The short-circuit signal is a signal for
5 short-circuiting the fourth relay 63. The medium
protection relay switching circuit 68 outputs the shortcircuit signal to the fourth relay 63 (S12). The fourth
relay 63 is short-circuited (S13). In FIG. 5, the central
processing unit is described as a “CPU”.
10 [0039] During the operation of the air conditioner 1A,
the medium protection relay switching circuit 68 determines
whether or not the value of the voltage detected by the
medium voltage detection circuit 67 is larger than the
first threshold (S14). The first threshold is a value used
15 to determine whether or not the voltage detected by the
medium voltage detection circuit 67 is an overvoltage.
More specifically, in a case where the voltage detected by
the medium voltage detection circuit 67 is the overvoltage,
the value of the voltage detected by the medium voltage
20 detection circuit 67 is larger than the first threshold.
[0040] In a case of determining that the value of the
voltage detected by the medium voltage detection circuit 67
is larger than the first threshold (Yes in S14), the medium
protection relay switching circuit 68 outputs the release
25 signal to the fourth relay 63 (S15). The fourth relay 63
is in the released state according to the release signal
(S16). In a case of determining that the value of the
voltage detected by the medium voltage detection circuit 67
is equal to or less than the first threshold (No in S14),
30 the medium protection relay switching circuit 68 performs
the operation in step S14 again.
[0041] As described above, the indoor unit 2A included
in the air conditioner 1A according to the second
15
embodiment includes the fourth relay 63 that is in one of
the short-circuit state or the released state according to
the switching signal to be supplied, the medium voltage
detection circuit 67 that detects the voltage, and the
5 medium protection relay switching circuit 68 that outputs
the switching signal for causing the fourth relay 63 to be
in the released state in a case where the value of the
voltage detected by the medium voltage detection circuit 67
is larger than the predetermined first threshold, to the
10 fourth relay 63.
[0042] That is, in the second embodiment, the voltage
signal indicating the value of the voltage detected by the
medium voltage detection circuit 67 is received by the
medium protection relay switching circuit 68 that is
15 hardware, without passing through the CPU and the
microcomputer, and the medium protection relay switching
circuit 68 outputs the switching signal for causing the
fourth relay 63 to be in the released state in a case where
the value of the voltage detected by the medium voltage
20 detection circuit 67 is larger than the predetermined first
threshold, to the fourth relay 63. That is, in a case
where the value of the detected voltage is larger than the
first threshold, the application of the overvoltage to the
outdoor unit 3A is interrupted.
25 [0043] Therefore, since the voltage signal indicating
the value of the voltage detected by the medium voltage
detection circuit 67 is received by the medium protection
relay switching circuit 68 that is hardware without passing
through the CPU and the microcomputer, the air conditioner
30 1A can shorten the time after the detection of the
overvoltage to the interruption of the application of the
overvoltage. As a result, in the air conditioner 1A, it is
possible to prevent components of the air conditioner 1A
16
from being broken before the interruption of the
application of the overvoltage.
[0044] The configurations indicated in the above
embodiments indicate examples and can be combined with
5 other known techniques. Furthermore, the embodiments can
be combined with each other, and some configurations can be
partially omitted or changed without departing from the
gist.
10 Reference Signs List
[0045] 1, 1A air conditioner; 2, 2A indoor unit; 3, 3A
outdoor unit; 4 input power supply; 5, 5A, 6, 6A, 7, 7A,
26, 66 wiring line; 21, 31, 61, 71 terminal block; 22,
37a, 37b, 37c, 37d, 62, 75a, 75b, 75c, 75d diode; 23
15 first relay; 24, 34, 64, 74 serial communication circuit;
25, 38, 65, 76 capacitor; 27, 67 medium voltage detection
circuit; 32 second relay; 33 third relay; 35 power
supply voltage detection circuit; 36, 73 resistor; 37, 75
AC/DC converter; 39, 77 external voltage detection
20 circuit; 40, 78 DC/DC converter; 41, 79 intelligent power
module; 42 external protection relay switching circuit; 43,
69 central processing unit; 51 voltage comparator; 52
switching element; 53 relay; 63 fourth relay; 68 medium
protection relay switching circuit; 72 fifth relay.

WE CLAIM:
[Claim 1] An air conditioner including an indoor unit and
an outdoor unit, the air conditioner comprising:
a relay to be in one of a short-circuit state or a
5 released state according to a switching signal to be
supplied;
a voltage detection circuit to detect a voltage; and
a relay switching circuit to output a switching signal
for causing the relay to be in the released state in a case
10 where a value of the voltage detected by the voltage
detection circuit is larger than a predetermined first
threshold, to the relay, wherein
the relay, the voltage detection circuit, and the
relay switching circuit are disposed in the indoor unit or
15 the outdoor unit.
[Claim 2] The air conditioner according to claim 1, further
comprising a relay different from the relay.