AU2017431039B2 - Air conditioner - Google Patents

Abstract

An air conditioner (100) is provided with an indoor unit (2) and an outdoor unit (1). The indoor unit (2) starts up the outdoor unit (1). When the outdoor unit (1) is started up, the indoor unit (2) determines whether or not communication can be established between the outdoor unit (1) and the indoor unit (2). When the communication cannot be established, self-reception in which the indoor unit (2) receives a test signal generated by the indoor unit (2) is performed. The indoor unit (2) determines, on the basis of the result of the self-reception, whether or not to restart the outdoor unit (1).

Description

Docket No. PMDA-19158-EP,AU,SG, Status: Final

1

Technical Field

[0001] The present invention relates to an air

conditioner that includes an indoor unit and an outdoor

unit.

Background

[0002] In air conditioners, an indoor unit and an

outdoor unit are generally configured to be connected

together via three wires, i.e., a power line, a signal line,

and a power/signal common line.

[0003] In some air conditioners, when the air

conditioner is turned on or the air conditioner in the

operation standby state is resumed, commercial power is

applied from the indoor unit to the outdoor unit to

activate the outdoor unit while an inrush-current

prevention relay of the outdoor unit is operated. The

outdoor unit activated initiates and establishes

communication with the indoor unit. When communication

could not be established between the indoor unit and the

outdoor unit, the air conditioner performs again the

control of applying commercial power from the indoor unit

to the outdoor unit to attempt to establish communication.

[0004] [DELETED]

[0005] As described above, in some air conditioners,

when communication could not be established between the

indoor unit and the outdoor unit, the air conditioner

performs again the control of applying commercial power

from the indoor unit to the outdoor unit. However, if

commercial power is re-applied to the outdoor unit in such

a connection state that the outdoor unit can perform

communication, there is a problem in that unintended

overcurrent flows in the communication path and thus an outdoor-unit circuit may fail.

[0006] It is desired to address or ameliorate one or more disadvantages or limitations associated with the prior art, or at least to provide a useful alternative.

Summary

[0007] In at least one embodiment, the present invention provides an air conditioner which includes an indoor unit and an outdoor unit. The indoor unit activates the outdoor unit. Upon activating the outdoor unit, the indoor unit determines whether communication is capable of being established between the indoor unit and the outdoor unit. When the communication is not capable of being established, the indoor unit performs, without reactivating the outdoor unit, self-reception of receiving a first signal generated by the indoor unit. The indoor unit determines whether to reactivate the outdoor unit on a basis of a result of the self-reception.

Advantageous Effects of Embodiments

[0008] The air conditioner according to at least one embodiment of the present invention provides an advantage in that a failure of an outdoor-unit circuit that may occur due to re-application of commercial power can be prevented.

Brief Description of the Drawings

[0009] Preferred embodiments of the present invention are hereinafter described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 is a block diagram illustrating an electrical system of an air conditioner according to an embodiment. FIG. 2 is a flowchart illustrating an operation of the main parts of the air conditioner according to the embodiment. FIG. 3 is a block diagram illustrating an example configuration of an indoor communication circuit unit in the air conditioner according to the embodiment. FIG. 4 is a block diagram illustrating an example configuration of an outdoor communication circuit unit in the air conditioner according to the embodiment. FIG. 5 is a diagram for explaining an operation in the case of an instantaneous power failure. FIG. 6 is a block diagram illustrating an example of a hardware configuration in an indoor control unit according to the embodiment. FIG. 7 is a block diagram illustrating another example of a hardware configuration in the indoor control unit according to the embodiment.

Detailed Description

[0010] An air conditioner according to embodiments of the present invention will be explained below in detail with reference to the accompanying drawings. The present

Docket No. PMDA-19158-EP,AU,SG, Status: Final

4 invention is not limited to the following embodiments. In

the following descriptions, "physical connection" and "electrical connection" are not distinguished from each

other and are simply referred to as "connection".

[0011] Embodiment.

FIG. 1 is a block diagram illustrating an electrical

system of an air conditioner according to an embodiment.

As illustrated in FIG. 1, an air conditioner 100 in the

embodiment includes an outdoor unit 1 and an indoor unit 2

that activates the outdoor unit 1. FIG. 1 particularly

illustrates a connection state before the outdoor unit 1 is

activated.

[0012] A description will be first given of a schematic

configuration of the air conditioner 100 according to the

embodiment with reference to FIG. 1. The outdoor unit 1

and the indoor unit 2 are connected together via three

lines, i.e., a power line 24, a power/signal common line 25,

and a signal line 26. The outdoor unit 1 is connected to a

three-phase alternating-current (AC) power supply 3. A

three-phase AC voltage is applied to the outdoor unit 1 via

power lines 65. A single-phase AC voltage is applied from

two of the power lines 65 to the indoor unit 2 via the

power line 24 and the power/signal common line 25. This

means that the air conditioner 100 according to the

embodiment is configured such that the outdoor unit 1 is

supplied with three-phase AC power and the indoor unit 2 is

supplied with single-phase AC power.

[0013] The indoor unit 2 includes an indoor control unit

4 and an outdoor activation relay 8. The outdoor

activation relay 8 opens and closes a connection between

the power line 24 and the signal line 26. The wording "open and close a connection" indicates switching between

the unconnected state and the connected state. The indoor

Docket No. PMDA-19158-EP,AU,SG, Status: Final

5 control unit 4 controls the outdoor activation relay 8 such

that single-phase AC power is supplied between the signal

line 26 and the power/signal common line 25.

[0014] The outdoor unit 1 includes an outdoor rectifier

unit 9, a first inrush-current prevention relay 10, a power

supply relay 12, a second inrush-current prevention relay

13, a smoothing capacitor 14, an inverter circuit unit 15,

and an outdoor control unit 16. The outdoor unit 1 further

includes a communication-circuit power supply unit 18, an

outdoor communication circuit unit 19, a power supply

switch relay 20, an inrush-current-prevention-relay drive

unit 21, and a compressor 80. The compressor 80 is driven

by the inverter circuit unit 15.

[0015] In the outdoor unit 1, the outdoor rectifier unit

9 is connected to the power supply relay 12. The power

supply relay 12 opens and closes a connection between the

three-phase AC power supply 3 and the outdoor rectifier

unit 9. The outdoor rectifier unit 9 rectifies the output

of the three-phase AC power supply 3. The smoothing

capacitor 14 smooths the output of the outdoor rectifier

unit 9. The outdoor communication circuit unit 19

communicates with the indoor unit 2 via the power/signal

common line 25 and the signal line 26. The power supply

switch relay 20 is connected between the power/signal

common line 25 and the communication-circuit power supply

unit 18. When a single-phase AC voltage applied between

the power/signal common line 25 and the signal line 26 is

supplied to the inrush-current-prevention-relay drive unit

21 via the outdoor activation relay 8 of the indoor unit 2

and the power supply switch relay 20, the inrush-current

prevention-relay drive unit 21 operates. The first inrush

current prevention relay 10 is connected in parallel to the

power supply relay 12 and is controlled by the inrush-

Docket No. PMDA-19158-EP,AU,SG, Status: Final

6 current-prevention-relay drive unit 21. The second inrush

current prevention relay 13 is connected in parallel to the

first inrush-current prevention relay 10 and is controlled

by the outdoor control unit 16.

[0016] Next, a description will be given, in more detail,

of the configuration of the air conditioner 100 according

to the embodiment. The outdoor unit 1 includes an outdoor

terminal block 23. The outdoor terminal block 23 includes

an R terminal 27, an S terminal 28, a T terminal 29, an

outdoor Si terminal 30, an outdoor S2 terminal 31, and an

outdoor S3 terminal 32. The R terminal 27, the S terminal

28, and the T terminal 29 are connected to the three-phase

AC power supply 3. The power from the three-phase AC power

supply 3 is supplied to the outdoor unit 1 via the R

terminal 27, the S terminal 28, and the T terminal 29.

[0017] In the outdoor unit 1, the outdoor S1 terminal 30

is connected to the R terminal 27 and the outdoor S2

terminal 31 is connected to the S terminal 28. With these

connections, single-phase AC power is supplied to the

communication-circuit power supply unit 18 via the outdoor

S1 terminal 30 and the outdoor S2 terminal 31. The power

supplied to the outdoor S1 terminal 30 and the outdoor S2

terminal 31 is not limited to single-phase power between

the R terminal 27 and the S terminal 28 and can be single

phase power between any two of the three phases of the

three-phase AC power supply 3.

[0018] The indoor unit 2 includes an indoor terminal

block 22. The indoor terminal block 22 includes an indoor

S1 terminal 33, an indoor S2 terminal 34, and an indoor S3

terminal 35. The indoor S1 terminal 33 is connected to the

outdoor S1 terminal 30 via the power line 24. The indoor

S2 terminal 34 is connected to the outdoor S2 terminal 31

via the power/signal common line 25. The indoor S3

Docket No. PMDA-19158-EP,AU,SG, Status: Final

7 terminal 35 is connected to the outdoor S3 terminal 32 via

the signal line 26.

[0019] In addition to the indoor control unit 4 and the

outdoor activation relay 8 described above, the indoor unit

2 includes an indoor rectifier unit 5, an indoor

communication circuit unit 6, an indoor operation switching

unit 7, and a remote control receiving unit 36. The

outdoor activation relay 8 includes a terminal a, a

terminal b, and a terminal c. The terminal a is connected

to the indoor Si terminal 33. The terminal b is connected

to the indoor communication circuit unit 6. The terminal c

is a base of the outdoor activation relay 8 and is

connected to the indoor S3 terminal 35. The contact of the

outdoor activation relay 8 is connected to either the

terminal a or the terminal b. In other words, the outdoor

activation relay 8 switches whether to connect the indoor

S3 terminal 35 to the indoor S1 terminal 33 or to the

indoor communication circuit unit 6.

[0020] In the following descriptions, for the sake of

convenience, the state where the contact of the outdoor

activation relay 8 is connected to the terminal a is

referred to as "ON" and the state where the contact of the

outdoor activation relay 8 is connected to the terminal b

is referred to as "OFF".

[0021] When the outdoor activation relay 8 is OFF, the

contact of the outdoor activation relay 8 is connected to

the terminal b and thus the indoor S3 terminal 35 is

connected to the indoor communication circuit unit 6 via

the outdoor activation relay 8. With this connection, a

communication line is established between the outdoor unit

1 and the indoor unit 2 via the power/signal common line 25

and the signal line 26; therefore, the outdoor unit 1 and

the indoor unit 2 exchange various operation signals.

Docket No. PMDA-19158-EP,AU,SG, Status: Final

8

[0022] When the outdoor activation relay 8 is ON, the

contact of the outdoor activation relay 8 is connected to

the terminal a and thus the indoor S3 terminal 35 is

connected to the indoor Si terminal 33. With this

connection, single-phase AC power is supplied between the

power/signal common line 25 and the signal line 26.

[0023] The indoor Si terminal 33 is connected to the

indoor rectifier unit 5. The indoor S2 terminal 34 is

connected to the indoor rectifier unit 5 and the indoor

communication circuit unit 6. A single-phase AC voltage

applied between the power line 24 and the power/signal

common line 25 is converted into a direct-current (DC)

voltage by the indoor rectifier unit 5 and the power is

supplied to the indoor control unit 4.

[0024] The indoor operation switching unit 7 connected

to the indoor control unit 4 determines whether to reduce

the standby power that is the power consumed by the outdoor

unit 1 during operation standby. The example in FIG. 1 is

a case where whether to reduce the standby power is

determined depending on the connection state of jumper

wires. In the indoor operation switching unit 7, when a

jumper wire is connected between a terminal cl and a

terminal c2, the standby power is reduced, and when a

jumper wire is connected between the terminal c2 and a

terminal c3, the standby power is not reduced. Whether to

reduce the standby power can be switched by a switch

instead of using jumper wires.

[0025] The remote control receiving unit 36 is connected

to a remote controller 37 and the indoor control unit 4.

The remote control receiving unit 36 receives an operation

command from the remote controller 37 and transmits the

received command to the indoor control unit 4.

[0026] The outdoor unit 1 further includes an inrush-

Docket No. PMDA-19158-EP,AU,SG, Status: Final

9 current prevention resistor 11 and an outdoor operation

switching unit 17. The R terminal 27 in the outdoor unit 1

is connected to one end of each of the first inrush-current

prevention relay 10 and the second inrush-current

prevention relay 13 and to the terminal a that is one of

the terminals on one side of the power supply relay 12.

The other end of each of the first inrush-current

prevention relay 10 and the second inrush-current

prevention relay 13 is connected to one end of the inrush

current prevention resistor 11. The other end of the

inrush-current prevention resistor 11 is connected to the

outdoor rectifier unit 9 and to the terminal b that is one

of the terminals on the other side of the power supply

relay 12. Both ends of each of the first inrush-current

prevention relay 10 and the second inrush-current

prevention relay 13 are connected to the outdoor operation

switching unit 17.

[0027] The S terminal 28 is connected to the terminal c

that is another of the terminals on one side of the power

supply relay 12. A terminal d that is another of the

terminals on the other side of the power supply relay 12 is

connected to the outdoor rectifier unit 9. The T terminal

29 is connected to the outdoor rectifier unit 9 without

passing through the power supply relay 12.

[0028] In the example illustrated in FIG. 1, the

terminal a and the terminal c that are terminals on one

side of the power supply relay 12 are respectively

connected to the R terminal 27 and the S terminal 28;

however, there is no limitation thereto. It is sufficient

if any two of the R terminal 27, the S terminal 28, and the

T terminal 29 are connected to the terminal a and the

terminal c of the power supply relay 12.

[0029] A circuit unit is configured from a parallel

Docket No. PMDA-19158-EP,AU,SG, Status: Final

10 circuit of the first inrush-current prevention relay 10 and

the second inrush-current prevention relay 13 and the

inrush-current prevention resistor 11 connected in series

with the parallel circuit. The circuit unit is connected

at one end to the terminal a and connected at the other end

to the terminal b in FIG. 1; however, there is no

limitation thereto. The circuit unit may be connected at

one end to the terminal c and connected at the other end to

the terminal d. In other words, it is sufficient if one

end and the other end of the circuit unit are connected to

the input and output of any one of the contacts in the

power supply relay 12.

[00301 In FIG. 1, the power supply relay 12 is

illustrated as a two-contact relay; however, the power

supply relay 12 may be configured from two single-contact

relays.

[0031] The outdoor rectifier unit 9 rectifiers the AC

voltage from the three-phase AC power supply 3 to convert

it into a given DC voltage. The power supply relay 12 and

the second inrush-current prevention relay 13 are operated

under the control of the outdoor control unit 16. When the

power supply relay 12 and the second inrush-current

prevention relay 13 are not in operation, their contacts

are open as illustrated in FIG. 1.

[0032] The outdoor operation switching unit 17 is

connected to both ends of the first inrush-current

prevention relay 10 and is also connected to the outdoor

control unit 16. The outdoor operation switching unit 17

determines whether to reduce the standby power during

operation standby. The example in FIG. 1 is a case where

whether to reduce the standby power is determined depending

on the connection state of jumper wires. In the outdoor

operation switching unit 17, when a jumper wire is

Docket No. PMDA-19158-EP,AU,SG, Status: Final

11 connected between a terminal al and a terminal a2, the

standby power during operation standby is reduced. When a

jumper wire is connected between a terminal bl and a

terminal b2, these terminals bl and b2 form a current path

bypassing the first inrush-current prevention relay 10.

Thus, the standby power during operation standby is not

reduced. Information indicating whether to reduce the

standby power during operation standby is transmitted from

the outdoor operation switching unit 17 to the outdoor

control unit 16.

[00331 Both ends of the smoothing capacitor 14 are

connected to the outdoor rectifier unit 9. The DC voltage

smoothed by the smoothing capacitor 14 is applied to the

inverter circuit unit 15 and the outdoor control unit 16.

[0034] The power supply switch relay 20 includes a

terminal a, a terminal b, and a terminal c. The terminal a

is connected to the communication-circuit power supply unit

18. The terminal b is connected to the inrush-current

prevention-relay drive unit 21. The terminal c is

connected to the outdoor S2 terminal 31. The terminal c is

a base of the power supply switch relay 20 and is connected

to the outdoor S2 terminal 31. The contact of the power

supply switch relay 20 is connected to either the terminal

a or the terminal b. In other words, the power supply

switch relay 20 switches whether to connect the outdoor S2

terminal 31 to the inrush-current-prevention-relay drive

unit 21 or to the communication-circuit power supply unit

18.

[00351 In the following descriptions, for the sake of

convenience, the state where the contact of the power

supply switch relay 20 is connected to the terminal a is

referred to as "ON" and the state where the contact of the

power supply switch relay 20 is connected to the terminal b

Docket No. PMDA-19158-EP,AU,SG, Status: Final

12 is referred to as "OFF".

[00361 The outdoor control unit 16 controls the power

supply switch relay 20. When the power supply switch relay

20 is OFF, the contact of the power supply switch relay 20

is connected to the terminal b and thus the outdoor S2

terminal 31 is connected to the inrush-current-prevention

relay drive unit 21 via the power supply switch relay 20.

With this connection, when a single-phase alternating

current flows between the power/signal common line 25 and

the signal line 26 by the indoor unit 2, the inrush

current-prevention-relay drive unit 21 is energized.

Energization of the inrush-current-prevention-relay drive

unit 21 causes the contact of the first inrush-current

prevention relay 10 to close.

[0037] When the power supply switch relay 20 is ON, the

contact of the power supply switch relay 20 is connected to

the terminal a. In this case, the outdoor S2 terminal 31

is connected to the communication-circuit power supply unit

18 via the power supply switch relay 20. The

communication-circuit power supply unit 18 generates a DC

voltage from a single-phase AC voltage applied between the

power line 24 and the power/signal common line 25 and

applies this DC voltage to the outdoor communication

circuit unit 19. The DC voltage can be generated by a

half-wave rectifier circuit or a full-wave rectifier

circuit; however, any circuit can be used to generate the

DC voltage.

[00381 The inverter circuit unit 15, controlled by the

outdoor control unit 16, converts the applied DC voltage

into a given AC voltage at a given frequency. The inverter

circuit unit 15 applies the AC voltage obtained by the

conversion to the compressor 80 to drive the compressor 80.

[00391 Next, a description will be given of an operation

Docket No. PMDA-19158-EP,AU,SG, Status: Final

13 of the air conditioner 100 during operation standby with

reference to FIG. 1. First, power is supplied from the

three-phase AC power supply 3 to the outdoor unit 1 via the

R terminal 27, the S terminal 28, and the T terminal 29.

During operation standby, the contacts of the first inrush

current prevention relay 10, the second inrush-current

prevention relay 13, and the power supply relay 12 are

open; therefore, no power is supplied to the inverter

circuit unit 15, the outdoor operation switching unit 17,

and the outdoor control unit 16 that are outdoor-unit loads.

[0040] Although one end of the communication-circuit

power supply unit 18 is connected to the power line 24 via

the outdoor Si terminal 30, the other end of the

communication-circuit power supply unit 18 is not connected

to the outdoor S2 terminal 31 because of the power supply

switch relay 20. Thus, power is not supplied to the

communication-circuit power supply unit 18. Consequently,

power is not supplied to the outdoor communication circuit

unit 19, either. Although one end of the inrush-current

prevention-relay drive unit 21 is connected to the

power/signal common line 25 via the outdoor S2 terminal 31,

the other end of the inrush-current-prevention-relay drive

unit 21 is connected to the signal line 26 via the outdoor

S3 terminal 32. Thus, power is not supplied to the inrush

current-prevention-relay drive unit 21.

[0041] With the operation mode described above, power is

not supplied to the inverter circuit unit 15, the outdoor

control unit 16, the outdoor operation switching unit 17,

the communication-circuit power supply unit 18, and the

outdoor communication circuit unit 19 during operation

standby; therefore, the operation standby power in the

outdoor unit 1 is reduced.

[0042] Next, the operation before the air conditioner

Docket No. PMDA-19158-EP,AU,SG, Status: Final

14 100 starts its operation will be described. When power is

supplied from the three-phase AC power supply 3 to the

indoor unit 2 via the power line 24 and the power/signal

common line 25, the power is supplied to the indoor control

unit 4 and thus the indoor unit 2 is activated. After the

indoor unit 2 is activated, the settings of the indoor

operation switching unit 7 are identified. In the example

in FIG. 1, a jumper wire is connected between the terminal

cl and the terminal c2; therefore, it is determined that

the air conditioner reduces the standby power during

operation standby. The indoor control unit 4 transitions

to the state waiting for an input of an operation command

from the remote controller 37 via the remote control

receiving unit 36.

[0043] Upon receiving an operation command signal from

the remote controller 37, the indoor control unit 4 turns

on the outdoor activation relay 8 to activate the outdoor

unit 1. At this point in time, switching is made such that

the indoor S3 terminal 35 is disconnected from the indoor

communication circuit unit 6 but is connected to the indoor

Si terminal 33. With this control, a single-phase AC

voltage is applied between the outdoor S2 terminal 31 and

the outdoor S3 terminal 32.

[0044] The power supplied between the outdoor S2

terminal 31 and the outdoor S3 terminal 32 energizes the

inrush-current-prevention-relay drive unit 21 via the power

supply switch relay 20 and also causes the contact of the

first inrush-current prevention relay 10 to close. When

the contact of the first inrush-current prevention relay 10

is closed, the AC voltage from the three-phase AC power

supply 3 is converted into a DC voltage by the outdoor

rectifier unit 9. The DC voltage obtained by the

conversion is applied to the smoothing capacitor 14 and the

Docket No. PMDA-19158-EP,AU,SG, Status: Final

15 inverter circuit unit 15.

[0045] The inrush-current prevention resistor 11 is

inserted in the power supply path through the first inrush

current prevention relay 10; therefore, inrush current can

be prevented. The outdoor control unit 16 is activated by

the application of the DC voltage. The outdoor control

unit 16 activated closes the contact of the second inrush

current prevention relay 13. The outdoor control unit 16

monitors the voltage to which the smoothing capacitor 14 is

charged. After the outdoor control unit 16 determines that

the monitoring voltage becomes stable at a set voltage, the

outdoor control unit 16 closes the contact of the power

supply relay 12. Then, the outdoor control unit 16 opens

the contact of the second inrush-current prevention relay

13. The second inrush-current prevention relay 13 is a

relay used for increasing the likelihood of self-reset when

an instantaneous power failure occurs and for improving

user convenience. An instantaneous power failure is a

phenomenon that external power supply is temporarily

interrupted. The operation of the second inrush-current

prevention relay 13 in the case of an instantaneous power

failure will be described later.

[0046] After a given set time has elapsed since the

outdoor activation relay 8 is turned on, the indoor control

unit 4 turns off the outdoor activation relay 8. At this

point in time, switching is made such that the indoor S3

terminal 35 is disconnected from the indoor Si terminal 33

but is connected to the indoor communication circuit unit 6.

With this control, a single-phase AC voltage applied

between the outdoor S2 terminal 31 and the outdoor S3

terminal 32 is interrupted and thus the inrush-current

prevention-relay drive unit 21 is de-energized.

Consequently, the contact of the first inrush-current

Docket No. PMDA-19158-EP,AU,SG, Status: Final

16 prevention relay 10 is opened. With this operation, inrush

current during an outdoor-unit activation operation can be

prevented.

[0047] When the inrush-current-prevention-relay drive

unit 21 is de-energized, the outdoor control unit 16 turns

on the power supply switch relay 20 to switch the

connection state of the outdoor S2 terminal 31 such that

the outdoor S2 terminal 31 is disconnected from the inrush

current-prevention-relay drive unit 21 but is connected to

the communication-circuit power supply unit 18. With this

control, a single-phase AC voltage applied between the

outdoor Si terminal 30 and the outdoor S2 terminal 31 is

applied to the communication-circuit power supply unit 18.

The communication-circuit power supply unit 18 converts the

single-phase AC voltage into a given DC voltage and applies

the DC voltage to the outdoor communication circuit unit 19.

[0048] In the above descriptions, the first inrush

current prevention relay 10 is turned off after the outdoor

activation relay 8 is turned off by the indoor control unit

4; however, this order may be reversed and the power supply

switch relay 20 may be first turned on. When the power

supply switch relay 20 is turned on, the inrush-current

prevention-relay drive unit 21 is de-energized and thus the

first inrush-current prevention relay 10 is turned off.

Thus, even if the order is reversed, the outdoor unit 1 can

still be activated.

[0049] Next, a description will be given of an operation

of the main parts of the air conditioner 100 according to

the embodiment with reference to FIGS. 1 to 4. FIG. 2 is a

flowchart illustrating an operation of the main parts of

the air conditioner 100 according to the embodiment. FIG.

3 is a block diagram illustrating an example configuration

of the indoor communication circuit unit 6 in the air

Docket No. PMDA-19158-EP,AU,SG, Status: Final

17 conditioner 100 according to the embodiment. FIG. 4 is a

block diagram illustrating an example configuration of the

outdoor communication circuit unit 19 in the air

conditioner 100 according to the embodiment.

[00501 As illustrated in FIG. 3, the indoor

communication circuit unit 6 includes a transmitting unit

38, a receiving unit 39, a transmission control unit 50,

and a reception control unit 51. The transmitting unit 38

and the receiving unit 39 connected in series are

interposed between the power/signal common line 25 and the

signal line 26.

[0051] As illustrated in FIG. 4, the outdoor

communication circuit unit 19 includes a transmitting unit

40, a receiving unit 41, a transmission control unit 60,

and a reception control unit 61. The transmitting unit 40

and the receiving unit 41 connected in series are

interposed between the power/signal common line 25 and the

signal line 26.

[0052] At step Si, the indoor unit 2 is activated. As

described above, the indoor unit 2 is activated by

supplying power from the three-phase AC power supply 3 to

the indoor unit 2.

[00531 At step S2, the outdoor activation relay 8 is

controlled to be in an on state. With this control, the

indoor S3 terminal 35 is connected to the indoor S1

terminal 33 and a single-phase AC voltage is applied

between the outdoor S2 terminal 31 and the outdoor S3

terminal 32. When a single-phase AC voltage is applied

between the outdoor S2 terminal 31 and the outdoor S3

terminal 32, the outdoor unit 1 is activated.

[0054] The outdoor activation relay 8 that has been

controlled to be in an on state is returned to an off state.

Consequently, switching is made such that the indoor S3

Docket No. PMDA-19158-EP,AU,SG, Status: Final

18 terminal 35 is disconnected from the indoor Si terminal 33

but is connected to the indoor communication circuit unit 6.

[00551 At step S3, the power supply switch relay 20 is

controlled to be in an on state. With this control,

switching is made such that the outdoor S2 terminal 31 is

disconnected from the inrush-current-prevention-relay drive

unit 21 but is connected to the communication-circuit power

supply unit 18. Consequently, a single-phase AC voltage is

applied to the communication-circuit power supply unit 18.

[00561 At step S4, power is supplied to the

communication-circuit power supply unit 18. The

communication-circuit power supply unit 18 supplied with

power converts the single-phase AC voltage into a given DC

voltage and applies the DC voltage obtained by the

conversion to the outdoor communication circuit unit 19.

[0057] At step S5, communication is initiated between

the outdoor unit 1 and the indoor unit 2. The outdoor unit

1 takes the initiative to the communication at step S5. In

other words, the outdoor unit 1 serves as a master and the

indoor unit 2 serves as a slave. Details of the

communication operation performed between the outdoor unit

1 and the indoor unit 2 will be described later.

[00581 At step S6, it is determined whether

communication can be established between the outdoor unit 1

and the indoor unit 2. When communication can be

established (Yes at step S6), the process proceeds to step

S7. At step S7, steady communication is performed between

the outdoor unit 1 and the indoor unit 2. In the steady

communication, various pieces of information necessary for

the control of the air conditioner 100 are exchanged.

[00591 At step S8, the outdoor control unit 16 in the

outdoor unit 1 receives an operation start command from the

indoor unit 2 and starts a heating operation or a cooling

Docket No. PMDA-19158-EP,AU,SG, Status: Final

19 operation.

[00601 In contrast, when communication cannot be

established (No at step S6), the process proceeds to step

S9. At step S9, a process of checking the communication

path is performed, which includes processes at steps S10 to

S16. As described above, if commercial power is re-applied

to the outdoor unit 1 in such a connection state that the

outdoor unit 1 can perform communication, unintended

overcurrent may flow in the communication path and thus the

outdoor-unit circuit may fail. To counter this, the

process at step S9 is added.

[0061] At step S10, in the indoor unit 2, a test signal

is transmitted and it is determined whether self-reception

is possible. The self-reception indicates a process of

receiving a signal generated by the transmitting unit 38 of

the indoor unit 2 by the receiving unit 39 of the

aforementioned indoor unit 2. The reception process

involved in the self-reception can be performed

independently of, or asynchronously to, the process at step

S5. Details of the reception process involved in the self

reception will be described later. A test signal can be in

any form of a communication signal as long as it can check

the function of the self-reception. The signal generated

by the transmitting unit 38, i.e., a test signal, is in

some cases referred to as a "first signal" for the sake of

convenience.

[0062] When the self-reception of a test signal is

successful (Yes at step S10), the process proceeds to step

Sl. Successful self-reception of a test signal means that

the communication path is connected correctly between the

indoor unit 2 and the outdoor unit 1 and that the

respective functions of the transmitting unit 38 and the

receiving unit 39 of the indoor unit 2 are normal. In

Docket No. PMDA-19158-EP,AU,SG, Status: Final

20 other words, when the self-reception is successful, it is

determined that a communication operation in the indoor

unit 2 is normal. Thus, at step Sl, the indoor unit 2

waits for receipt of a signal through outdoor transmission.

The outdoor transmission indicates an operation of

transmitting a signal from the outdoor unit 1 to the indoor

unit 2. At step Sl, the indoor unit 2 is in a standby

state to determine whether the receiving unit 39 of the

indoor unit 2 can receive a signal generated by the

transmitting unit 40 of the outdoor unit 1. The signal

generated when the outdoor transmission is performed is in

some cases referred to as a "second signal" for the sake of

convenience.

[00631 After step Sl, the process proceeds to step S12.

At step S12, it is determined again whether communication

can be established between the outdoor unit 1 and the

indoor unit 2. The determination of whether communication

can be established is performed based on the result

indicating whether the receiving unit 39 of the indoor unit

2 can receive the signal transmitted from the transmitting

unit 40 of the outdoor unit 1.

[0064] When communication can be established (Yes at

step S12), the process proceeds to step S7. The operations

at step S7 and subsequent steps are performed as described

above and thus a description thereof is omitted.

[00651 In contrast, when communication cannot be

established (No at step S12), the process proceeds to step

S13. At step S13, it is determined that a communication

error has occurred and the process in the flowchart in FIG.

2 ends.

[00661 The description here refers back to the

determination process at step S10. When the self-reception

of a test signal in the indoor unit 2 is not successful (No

Docket No. PMDA-19158-EP,AU,SG, Status: Final

21 at step S10), the process proceeds to step S14. When the

self-reception of a test signal is not successful, there is

a possibility that the functions of the transmitting unit

40 and the receiving unit 41 of the outdoor unit 1 may not

be normal in addition to the possibility that the

communication path may not be connected correctly between

the outdoor unit 1 and the indoor unit 2 and the functions

of the transmitting unit 38 and the receiving unit 39 of

the indoor unit 2 are not normal. Thus, at step S14, the

outdoor unit 1 is reactivated. The outdoor unit 1 is

reactivated by turning on the outdoor activation relay 8.

[0067] After step S14, the process proceeds to step S15.

At step S15, it is determined whether the number of times

the outdoor unit 1 is reactivated is within a predetermined

number of times. When the number of times the outdoor unit

1 is reactivated is within the predetermined number of

times (Yes at step S15), the process returns to step S2 and

the processes at step S2 and subsequent steps are repeated.

[0068] In contrast, when the number of times the outdoor

unit 1 is reactivated exceeds the predetermined number of

times (No at step S15), the process proceeds to step S16.

At step S16, it is determined that a communication error

has occurred and the process in the flowchart in FIG. 2

ends.

[0069] As described above, in the flowchart in FIG. 2,

the process at step S10 is added. With this process, in a

connection state where the outdoor unit 1 can perform

communication, commercial power can be prevented from being

re-applied to the outdoor unit 1. Consequently, in a state

where a communication circuit is formed, an unintended

failure of an outdoor-unit circuit can be prevented.

[0070] In the flowchart in FIG. 2, the process at step

S15 is added. This process can eliminate the situation

Docket No. PMDA-19158-EP,AU,SG, Status: Final

22 where the outdoor unit 1 cannot be reactivated due to an

accidental factor; therefore, it is possible to increase

the accuracy in determination of an occurrence of a

communication error.

[0071] Next, a description will be given of a

communication operation performed between the outdoor unit

1 and the indoor unit 2. Hereinafter, communication

between the outdoor unit 1 and the indoor unit 2 is

referred to as "indoor-outdoor communication" as

appropriate.

[0072] A communication current supplied from the

communication-circuit power supply unit 18 flows between

the power/signal common line 25 and the signal line 26. A

communication current is current used for communication

between the outdoor unit 1 and the indoor unit 2. The

outdoor unit 1 and the indoor unit 2 perform communication

by detecting a current flowing state and a no-current

flowing state.

[0073] The transmitting unit 38 includes an element for

switching a state of a path through which a communication

current flows during indoor-outdoor communication to either

a communication current flowing state or a no

communication-current flowing state. One example of the

element is a photocoupler. Hereinafter, a path through

which a communication current flows during indoor-outdoor

communication is referred to as a "current loop". The

current loop is formed by inserting the transmitting unit

38 and the receiving unit 39 of the indoor unit 2 and the

transmitting unit 40 and the receiving unit 41 of the

outdoor unit 1 in series between the power/signal common

line 25 and the signal line 26. In the following

descriptions, a state where a communication current flows

in the current loop is referred to as an "ON state" or

Docket No. PMDA-19158-EP,AU,SG, Status: Final

23 simply "ON" and a state where a communication current does

not flow in the current loop is referred to as an "OFF

state" or simply "OFF".

[0074] In the indoor unit 2, the transmitting unit 38

controls ON/OFF of the current loop in accordance with the

control by the transmission control unit 50. The

transmitting unit 38 transmits data to the outdoor unit 1

in accordance with ON/OFF control of the current loop.

[0075] In the indoor unit 2, the receiving unit 39

includes an element for receiving data transmitted from the

outdoor unit 1. The receiving unit 39 detects whether the

value of a communication current flowing in the current

loop is larger than or smaller than a current threshold to

receive data. One example of the element is a photocoupler.

The receiving unit 39 outputs the reception result to the

reception control unit 51.

[0076] The transmission control unit 50 controls ON/OFF

of the transmitting unit 38 in accordance with whether the

transmission data indicates "0" or "1". When the

transmission data indicates "0", the transmitting unit 38

may be controlled to be ON or may be controlled to be OFF.

When the transmission data indicates "1", the transmitting

unit 38 may be controlled to be ON or may be controlled to

be OFF.

[0077] The reception control unit 51 determines that the

reception data indicates "0" or "1" in accordance with the

output of the receiving unit 39.

[0078] In the outdoor unit 1, the transmitting unit 40

includes an element for switching a state of the current

loop between a communication current flowing state and a

no-communication-current flowing state. One example of the

element is a photocoupler. The transmitting unit 40

controls ON/OFF of the current loop in accordance with the

Docket No. PMDA-19158-EP,AU,SG, Status: Final

24 control by the transmission control unit 60. The

transmitting unit 40 transmits data to the indoor unit 2 in

accordance with ON/OFF control of the current loop.

[0079] In the outdoor unit 1, the receiving unit 41

includes an element for receiving data transmitted from the

indoor unit 2. The receiving unit 41 detects whether the

value of a communication current flowing in the current

loop is larger than or smaller than a communication current

threshold to receive data. One example of the element is a

photocoupler. The receiving unit 41 outputs the output

result to the reception control unit 61.

[0080] The transmission control unit 60 controls ON/OFF

of the transmitting unit 40 in accordance with whether the

transmission data indicates "0" or "1". When the

transmission data indicates "0", the transmitting unit 40

may be controlled to be ON or may be controlled to be OFF.

When the transmission data indicates "1", the transmitting

unit 40 may be controlled to be ON or may be controlled to

be OFF.

[0081] The reception control unit 61 determines that the

reception data indicates "0" or "1" in accordance with the

output of the receiving unit 41.

[0082] The operation flow when data is transmitted from

the outdoor unit 1 to the indoor unit 2 will be described

below. When the indoor unit 2 receives data transmitted

from the outdoor unit 1, the transmission control unit 50

of the indoor unit 2 controls the transmitting unit 38 of

the indoor unit 2 such that it is ON.

[0083] Step 1: The transmission control unit 60 of the

outdoor unit 1 controls ON/OFF of the transmitting unit 40

of the outdoor unit 1 in accordance with whether the

transmission data indicates "0" or "1".

Step 2: The receiving unit 39 of the indoor unit 2

Docket No. PMDA-19158-EP,AU,SG, Status: Final

25 outputs the reception result to the reception control unit

51 of the indoor unit 2.

Step 3: The reception control unit 51 of the indoor

unit 2 determines whether the reception data indicates "0"

or "1" in accordance with the input result.

[0084] The operation flow when data is transmitted from

the indoor unit 2 to the outdoor unit 1 will be described

below. When the outdoor unit 1 receives data transmitted

from the indoor unit 2, the transmission control unit 60 of

the outdoor unit 1 controls the transmitting unit 40 of the

outdoor unit 1 such that it is ON.

[0085] Step 1: The transmission control unit 50 of the

indoor unit 2 controls ON/OFF of the transmitting unit 38

of the indoor unit 2 in accordance with whether the

transmission data indicates "0" or "1".

Step 2: The receiving unit 41 of the outdoor unit 1

outputs the reception result to the reception control unit

61 of the outdoor unit 1.

Step 3: The reception control unit 61 of the outdoor

unit 1 determines whether the reception data indicates "0"

or "1" in accordance with the input result.

[0086] The operation flow when the indoor unit 2

performs the self-reception of a test signal will be

described below. The indoor unit 2 performs the self

reception of a test signal at the time when the

transmission control unit 60 of the outdoor unit 1 controls

the transmitting unit 40 of the outdoor unit 1 such that it

is ON.

[0087] Step 1: The transmission control unit 50 of the

indoor unit 2 controls ON/OFF of the transmitting unit 38

of the indoor unit 2 in accordance with whether the

transmission data indicates "0" or "1".

Step 2: The receiving unit 39 of the indoor unit 2

Docket No. PMDA-19158-EP,AU,SG, Status: Final

26 outputs the reception result to the reception control unit

51 of the indoor unit 2.

Step 3 The reception control unit 51 of the indoor

unit 2 determines whether the reception data indicates "0"

or "1" in accordance with the input result.

[00881 Next, a description will be given of an operation

of the second inrush-current prevention relay 13 in the

case of an instantaneous power failure with reference to

FIGS. 1 to 5. FIG. 5 is a diagram for explaining an

operation in the case of an instantaneous power failure.

As described above, the second inrush-current prevention

relay 13 is a relay used for increasing the likelihood of

self-reset when an instantaneous power failure occurs and

for improving user convenience.

[00891 FIG. 5 illustrates, in association with the bus

voltage, a sequence operation of the power supply relay 12

on the left side and a sequence operation of the second

inrush-current prevention relay 13 on the right side. The

"bus voltage" here indicates a voltage of a DC bus that

connects the outdoor rectifier unit 9 and the inverter

circuit unit 15, and it matches the voltage of the

smoothing capacitor 14 in the example in FIG. 1. In the

following descriptions, the "voltage of the smoothing

capacitor 14" is referred to as the "bus voltage".

[00901 As described above, the bus voltage is monitored

by the outdoor control unit 16. When power supply is

interrupted, the bus voltage drops because some load is

connected to the circuit. The larger the load is, the

faster the bus voltage drops. The contact of the power

supply relay 12 is closed while the outdoor unit 1 is

energized; therefore, if power supply is immediately

restored, the bus voltage instantaneously rises and returns

to the voltage obtained by smoothing the power-supply

Docket No. PMDA-19158-EP,AU,SG, Status: Final

27 voltage. However, if power supply is not restored, the bus

voltage continues to drop.

[0091] When the bus voltage falls below a first voltage

threshold Vth1, the contact of the power supply relay 12 is

opened and then the contact of the second inrush-current

prevention relay 13 is closed. Because these operations

are performed in sequence, the bus voltage at the time when

the contact of the second inrush-current prevention relay

13 is closed may be a voltage Vthl', which is lower than

the first voltage threshold Vth1.

[0092] Even when the bus voltage falls below the first

voltage threshold Vth1 and further continues to drop, the

outdoor control unit 16 keeps the contact of the second

inrush-current prevention relay 13 closed as long as the

bus voltage can still cause the outdoor control unit 16 to

operate. When the power supply is restored at a voltage at

which the outdoor control unit 16 can operate, the voltage

of the smoothing capacitor 14 can be restored by using the

path through the second inrush-current prevention relay 13

and the inrush-current prevention resistor 11. Because the

inrush-current prevention resistor 11 is present in the

path, an inrush current value can be limited and thus a

failure of a circuit in the subsequent stage, e.g., the

outdoor rectifier unit 9, due to excessive inrush current

can be prevented.

[0093] When the bus voltage is restored and the power

supply voltage is returned to a stable voltage VDD, the

outdoor control unit 16 determines that the power-supply

voltage becomes stable at the stable voltage VDD.

Thereafter, the outdoor control unit 16 closes the contact

of the power supply relay 12 and then opens the contact of

the second inrush-current prevention relay 13. As long as

the three-phase AC power supply 3 keeps supplying power,

Docket No. PMDA-19158-EP,AU,SG, Status: Final

28 the current for charging the smoothing capacitor 14 is

supplied to the smoothing capacitor 14 via the power supply

relay 12 without passing through the second inrush-current

prevention relay 13. The above control operations can

reduce unnecessary power used in the air conditioner 100.

[0094] Finally, a description will be given of a

hardware configuration for implementing the function of the

indoor control unit 4 according to the embodiment with

reference to FIGS. 6 and 7. FIG. 6 is a block diagram

illustrating an example of a hardware configuration in the

indoor control unit according to the embodiment. FIG. 7 is

a block diagram illustrating another example of a hardware

configuration in the indoor control unit according to the

embodiment.

[0095] To implement the function of the indoor control

unit 4 according to the embodiment, the indoor control unit

4 can be configured to include a processor 200 for

executing computations, a memory 202 storing programs read

by the processor 200, and an interface 204 for inputting

and outputting signals.

[0096] The processor 200 may be a computing unit such as

an arithmetic unit, a microprocessor, a microcomputer, a

central processing unit (CPU), or a digital signal

processor (DSP). Examples of the memory 202 include a

nonvolatile or volatile semiconductor memory such as a

random access memory (RAM), a read only memory (ROM), a

flash memory, an erasable programmable read only memory

(EPROM), or an electrically erasable programmable read only

memory (EEPROM), a magnetic disk, a flexible disk, an

optical disk, a compact disk, a mini disk, and a digital

versatile disk (DVD).

[0097] The memory 202 stores programs for implementing a

function of the indoor control unit 4 and a table referred

Docket No. PMDA-19158-EP,AU,SG, Status: Final

29 to by the processor 200. The processor 200 can perform the

computation processes described above by exchanging

necessary information via the interface 204, executing the

programs stored in the memory 202, and referring to the

table stored in the memory 202. The computation results by

the processor 200 can be stored in the memory 202.

[00981 The processor 200 and the memory 202 illustrated

in FIG. 6 may be replaced by a processing circuit 203 as

illustrated in FIG. 7. The processing circuit 203 is, for

example, a single circuit, a combined circuit, an

application specific integrated circuit (ASIC), a field

programmable gate array (FPGA), or a combination of them.

[00991 The configurations described in the above

embodiments illustrate examples of an aspect of the present

invention, and can be combined with another known art, or

can be partly omitted or changed without departing from the

scope of the present invention.

[0100] Throughout this specification and the claims

which follow, unless the context requires otherwise, the

word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of

a stated integer or step or group of integers or steps but

not the exclusion of any other integer or step or group of

integers or steps.

[0101] The reference in this specification to any prior

publication (or information derived from it), or to any

matter which is known, is not, and should not be taken as

an acknowledgment or admission or any form of suggestion

that that prior publication (or information derived from

it) or known matter forms part of the common general

knowledge in the field of endeavour to which this

specification relates.

Docket No. PMDA-19158-EP,AU,SG, Status: Final

30 Reference Signs List

[0102] 1 outdoor unit; 2 indoor unit; 3 three-phase

AC power supply; 4 indoor control unit; 5 indoor

rectifier unit; 6 indoor communication circuit unit; 7

indoor operation switching unit; 8 outdoor activation

relay; 9 outdoor rectifier unit; 10 first inrush-current

prevention relay; 11 inrush-current prevention resistor;

12 power supply relay; 13 second inrush-current

prevention relay; 14 smoothing capacitor; 15 inverter

circuit unit; 16 outdoor control unit; 17 outdoor

operation switching unit; 18 communication-circuit power

supply unit; 19 outdoor communication circuit unit; 20

power supply switch relay; 21 inrush-current-prevention

relay drive unit; 22 indoor terminal block; 23 outdoor

terminal block; 24 power line; 25 power/signal common

line; 26 signal line; 27 R terminal; 28 S terminal; 29

T terminal; 30 outdoor S1 terminal; 31 outdoor S2

terminal; 32 outdoor S3 terminal; 33 indoor S1 terminal;

34 indoor S2 terminal; 35 indoor S3 terminal; 36 remote

control receiving unit; 37 remote controller; 38, 40

transmitting unit; 39, 41 receiving unit; 50, 60

transmission control unit; 51, 61 reception control unit;

65 power line; 80 compressor; 100 air conditioner; 200

processor; 202 memory; 203 processing circuit; 204

interface.

Claims (6)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An air conditioner that comprises an indoor unit and an outdoor unit and in which the indoor unit activates the outdoor unit, wherein upon activating the outdoor unit, the indoor unit determines whether communication is capable of being established between the indoor unit and the outdoor unit, and, when the communication is not capable of being established, the indoor unit performs, without reactivating the outdoor unit, self-reception of receiving a first signal generated by the indoor unit and determines whether to reactivate the outdoor unit on a basis of a result of the self-reception.

2. The air conditioner according to claim 1, wherein when the indoor unit is capable of receiving the first signal in the self-reception, the indoor unit determines that a communication operation in the indoor unit is normal.

3. The air conditioner according to claim 1, wherein when the indoor unit is capable of receiving the first signal in the self-reception, the indoor unit waits for a second signal generated by the outdoor unit to be input, and, when the indoor unit is not capable of receiving the second signal, the indoor unit determines that a communication error occurs without reactivating the outdoor unit.

4. The air conditioner according to claim 1, wherein when the indoor unit is capable of receiving the first signal in the self-reception, the indoor unit waits for a second signal generated by the outdoor unit to be input, and, when the indoor unit is capable of receiving the second signal, the indoor unit performs steady communication between the indoor unit and the outdoor unit.

5. The air conditioner according to claim 1, wherein when the indoor unit is not capable of receiving the first signal in the self-reception, the indoor unit reactivates the outdoor unit.

6. The air conditioner according to any one of claims 1 to 5, wherein the indoor unit and the outdoor unit are connected together via three lines including a power line, a power/signal common line, and a signal line, the indoor unit and the outdoor unit each include a transmitting unit and a receiving unit, the transmitting unit and the receiving unit of the indoor unit and the transmitting unit and the receiving unit of the outdoor unit are inserted in series between the power/signal common line and the signal line to form a current loop, and the indoor unit and the outdoor unit communicate with each other by detecting a communication current flowing in the current loop.

PMDA-19158-PCT

PMDA-19158-PCT

PMDA-19158-PCT

PMDA-19158-PCT

DD

PMDA-19158-PCT