JP2009097760A - Communication control device of air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control device of an air conditioner capable of surely protecting various elements on a communication path with a simple and inexpensive constitution by performing high-speed response to overcurrent caused by wrong wiring and the like. <P>SOLUTION: In this communication control device 1 of the air conditioner which has an outdoor unit 2 and an indoor unit 3 connected with the outdoor unit 2 by two AC power wires and one communication wire, and in which the transmission of a signal for controlling an operation between the outdoor unit 2 and the indoor unit 3 is performed by using one of the AC power wires as a line N in common use, and the outdoor unit 2 and the indoor unit 3 comprises transmitting/receiving circuits 21, 31 connected with a communication path 6 formed by the line N in common use in series, the outdoor unit 2 or the indoor unit 3, or the outdoor unit 2 and the indoor unit 3 comprise electric current limiting circuits 24, 34 connected with the communication path 6 in series. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication control device for an air conditioner that performs data transmission between an outdoor unit and an indoor unit in a split type air conditioner.

  In a so-called split type (indoor / outdoor separation type) air conditioner in which an outdoor unit is installed outside the building and an indoor unit is installed inside the building, each operation is controlled between the outdoor unit and the indoor unit. Signal transmission is performed. In addition to the method of transmitting signals by connecting the outdoor unit and the indoor unit through a total of four lines of two AC power supply lines and two communication lines, the signal transmission method includes, for example, the following: A method disclosed in Patent Document 1 has also been proposed.

  That is, in Patent Document 1, an outdoor unit and an indoor unit are connected by two AC power supply lines (L, N) and one communication line (S), and are performed between the outdoor unit and the indoor unit. In the transmission of the signal, one AC power supply line (N) is used as a shared line. FIG. 4 is an explanatory diagram for explaining this configuration. In this explanatory drawing, the structure of the communication circuit in the air conditioner 100 is simply shown.

  The air conditioner 100 includes an outdoor unit 101 and an indoor unit 102, and the outdoor unit 101 and the indoor unit 102 are connected to each other with a crossover portion 103 interposed therebetween. The outdoor unit 101 is connected to an AC power source 104 and supplies power to the indoor unit 102 via two AC power lines L and N. The outdoor unit 101 and the indoor unit 102 each include a signal line for transmitting a signal between each other. By connecting the terminal of the signal line to one of the AC power supply lines N and the communication line S, a communication path 105 for exchanging signals between the outdoor unit 201 and the indoor unit 102 is configured. The

  The outdoor unit 101 and the indoor unit 102 include transmission / reception circuits 106 and 107, respectively. These transmission / reception circuits 106 and 107 are composed of transmitting elements 106a and 107a and receiving elements 106b and 107b. When transmitting signals, the transmitting elements 106a and 107b are used. When receiving signals, the receiving elements 106b and 107b are connected. Done through. On the communication path 105, resistors 108 and 110 for limiting the current flowing through the communication path 105 on the respective sides of the outdoor unit 101 and the indoor unit 102 and a diode 109 for preventing a reverse voltage from being applied. 111 is provided. In addition, a communication DC power source 112 for supplying a current in one direction of the communication path 105 is provided in the middle of the communication path 105.

  In this configuration, a signal “0” or “1” is transmitted and received depending on whether or not a current is passed through the communication path 105. For example, when a signal is transmitted from the indoor unit 102 to the outdoor unit 101, the transmission element 106 a on the outdoor unit 101 side is turned on (conductive), and the transmission element 107 a of the indoor unit 102 has a current flowing through the communication path 105. Turn on and off. The ON / OFF signal is received by the receiving element 106b on the outdoor unit 101 side.

  However, in order for this communication path to function properly, it is necessary to correctly connect the outdoor unit and the indoor unit. This is because the elements on the transmission / reception circuit on this communication path are composed of low-voltage DC elements, and these elements will be destroyed if an AC power supply is erroneously applied due to incorrect wiring. In Patent Document 2 shown below, the following invention is disclosed as a method for preventing element destruction at the time of incorrect wiring.

That is, when a combination of a Zener diode and a positive temperature coefficient thermistor or fuse is inserted in series in the communication path, and AC power is applied to the communication path due to miswiring, the Zener diode causes the Zener diode to exceed the Zener voltage in the reverse direction. No voltage is applied, and no overvoltage is applied to the element. When an overcurrent flows, the resistance value increases due to self-heating in the case of a positive thermistor and the current is suppressed, and in the case of a fuse, the current is cut off and cut off.
Japanese Patent Laid-Open No. 2-146456 Japanese Patent No. 3434098

  However, particularly in the configuration disclosed in Patent Document 2 described above, an inrush current due to a delay in the operation of the positive temperature coefficient thermistor or the fuse flows in the case of incorrect wiring, and the Zener diode may be destroyed.

  Further, if the transmitting element provided on the communication path is turned on, an overcurrent may flow through the receiving element and be destroyed. Therefore, in order to avoid this destruction and protect the transmission / reception circuit, etc., it is necessary to select a component such as an element resistant to such an overcurrent, and there is a problem that the room for selecting the component is narrowed. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide more reliable communication with a simple and inexpensive configuration and a high-speed response to an overcurrent caused by miswiring or the like. An object of the present invention is to provide a communication control device for an air conditioner that can protect various elements on a path.

  A feature according to an embodiment of the present invention is that an outdoor unit, the outdoor unit, and an indoor unit connected by two AC power supply lines and one communication line are included, and between the outdoor unit and the indoor unit In the transmission of signals for operation control performed in the system, one of the AC power lines is used as a shared line, and the outdoor unit and the indoor unit are each connected in series to a communication path formed by the communication line and the shared line. In a communication control device for an air conditioner including a circuit and a receiving circuit, at least one of an outdoor unit and an indoor unit includes a current limiting circuit connected in series to a communication path.

  According to the present invention, communication of an air conditioner that can protect various elements on a communication path more reliably by performing a high-speed response with a simple and inexpensive configuration against an overcurrent caused by miswiring or the like. A control device can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an explanatory diagram simply showing the configuration of a communication control device 1 in an air conditioner. As shown in FIG. 1, the air conditioner including the communication control device 1 according to the first embodiment of the present invention includes an outdoor unit 2 and an indoor unit 3, and the outdoor unit 2 and the indoor unit 3 are They are connected to each other with the crossover part 4 interposed therebetween.

  The outdoor unit 2 is connected to an AC power source 5 and supplies power to the indoor unit 3 via two AC power lines L and N. Moreover, the outdoor unit 2 and the indoor unit 3 are each provided with the signal wire | line for transmitting a signal between each other. The terminals of these signal lines are any one of the AC power supply lines (in the embodiment of the present invention, the AC power supply line N is selected and hereinafter referred to as “shared line N” as appropriate). By connecting with the communication line S, a communication path 6 for exchanging signals between the outdoor unit 2 and the indoor unit 3 is configured.

  The outdoor unit 2 and the indoor unit 3 include transmission / reception circuits 21 and 31, respectively. These transmission / reception circuits 21 and 31 are composed of transmission elements 21a and 31a and reception elements 21b and 31b. When transmitting signals, the reception elements 21b and 31b are connected via the transmission elements 21a and 31a. Done through. Generally, a photocoupler in which a phototransistor is connected in series in a communication path is used for the transmitting elements 21a and 31a, and a photocoupler in which a photodiode is connected in series in a communication path is used for the receiving elements 21b and 31b. . Although not shown, the input of the transmitting element 21a and the output of the receiving element 21b of the outdoor unit 2 are connected to an outdoor control circuit. On the other hand, the input of the transmitting element 31a and the output of the receiving element 31b of the indoor unit 3 are connected to the indoor control circuit.

  Further, on the communication path 6, resistors 22 and 32 that limit the current flowing through the communication path 6 on the respective sides of the outdoor unit 2 and the indoor unit 3 and a diode 23 for preventing a reverse voltage from being applied. 33 is provided. Further, a communication DC power source (in FIG. 1 to FIG. 3, “communication DC power source”) 51 is provided in one or both of the outdoor unit 2 and the indoor unit 3, and the output thereof is communication. A current is supplied to the path 6 so as to flow in one direction.

  Current limiting circuits 24 and 34 are provided on the communication path 6 and on the respective sides of the outdoor unit 2 and the indoor unit 3. When the outdoor unit 2 and the indoor unit 3 are electrically connected, it is necessary to appropriately connect the two AC power supply lines L and N and the communication line S. For example, the common line in the outdoor unit 2 is erroneously connected. When an AC power supply line L that is not N is connected to the communication line S, each element, circuit, etc. provided on the communication path 6 is destroyed. That is, as described above, the transmission elements 21a, 31a, 21b, and 31b are configured by elements for a low-voltage DC circuit, so that the communication path 6 is destroyed when an AC power supply is applied due to miswiring. For this purpose, current limiting circuits 24 and 34 are provided on the communication path 6.

  In the communication control device 1 shown in FIG. 1, in both the outdoor unit 2 and the indoor unit 3, the current limiting circuits 24 and 34 are provided between the transmission / reception circuits 21 and 31 and the current limiting resistors 22 and 32. As long as it is on the communication path 6, it may be provided in any part omitted in FIG. In the communication control device 1 shown in FIG. 1, both the outdoor unit 2 and the indoor unit 3 are provided with the current limiting circuits 24 and 34, but the current limiting circuit is provided only in either the outdoor unit 2 or the indoor unit 3. May be provided.

  The current limiting circuit 24 is a circuit that is generally used. As shown in FIG. 1, the current limiting circuit 24 is provided on the communication path 6 on the first transistor 24a, the second transistor 24b, the DC power supply 24c, and The first current limiting resistor 24d provided between the first transistor 24a and the transmission / reception circuit 21 and the second current limiting resistor 24e provided between the DC power supply 24c and the second transistor 24b. The

  Specifically, in the current limiting circuit 24, the emitter and collector of the first transistor 24a are inserted in the middle of the communication path 6, and the DC output of the DC power supply 24c is supplied to the base of the first transistor 24a. . The base of the second transistor 24b is connected to the communication path 6 between the emitter of the first transistor 24a and the first current limiting resistor 24d, and the emitter of the second transistor 24b is connected to the first current limiting resistor 24d. The other end, which is connected between the current limiting resistor 24d and the transmission / reception circuit 21, is connected to the base of the first transistor.

  The configuration of the current limiting circuit 34 provided on the indoor unit 3 side is also the same. In FIG. 1 to FIG. 3, the direct current power source constituting the current limiting circuit is represented as “DC power source”.

  The first transistors 24a and 34a employ transistors having higher breakdown voltage and higher allowable collector loss than the second transistors 24b and 34b. This is to avoid the destruction of the first transistors 24a and 34a to which a high voltage is applied due to an overcurrent caused by miswiring in order to avoid destruction of elements on the communication path 6. .

  That is, normally, the second transistors 24b and 34b are in an OFF state, and a sufficient base current is supplied from the DC power sources 41 and 51 to the first transistors 24a and 34a. Is turned on, and the collector-emitter becomes completely conductive, and the communication path 6 becomes conductive. At this time, since the first transistors 24a and 34a are in the complete ON state, the power loss between the collector and the emitter is sufficiently small.

  However, if the commercial power supply voltage is applied as it is to the communication path 6 due to incorrect wiring, the voltage across the first current limiting resistors 24d and 34d exceeds the VBE of the second transistors 24b and 34b. The transistors 24b and 34b are turned on, and the first transistors 24a and 34a are deprived of the base current and become unsaturated. As a result, the value of the current flowing between the collector and the emitter of the first transistors 24a and 34a becomes a resistance value obtained by dividing VBE of the second transistors 24b and 34b by the first current limiting resistors 24d and 34d. Restrict. Therefore, by setting the resistance values of the first current limiting resistors 24d and 34d appropriately, overcurrent due to incorrect wiring can be suppressed. At this time, in order to bear the power loss of the communication path 6 between the collector and emitter of the first transistors 24a and 34a, it is required to have a high breakdown voltage and a high allowable collector loss.

  In the current limiting circuits 24 and 34 in the first embodiment, all of the first transistors 24a and 34a and the second transistors 24b and 34b are NPN type.

  Thus, by providing the current limiting circuits 44 and 54 on the communication path 6, the communication path 6 can be surely secured by performing a high-speed response with a simple and inexpensive configuration against an overcurrent caused by miswiring or the like. It is possible to provide a communication control device for an air conditioner that can protect the upper element.

  In particular, in the configuration of the invention disclosed in Patent Document 2 described above, for example, when an inrush current occurs, a positive temperature coefficient thermistor or a fuse may not be able to cope. For this reason, it is necessary to increase the resistance of the elements provided on the communication path in advance.

  In the configuration described in the embodiment of the present invention, no positive characteristic thermistor or fuse is used, so that there is no response delay. Therefore, by providing the current limiting circuits 44 and 54, it is possible to reliably protect the elements on the communication path from overcurrent caused by miswiring, etc., and therefore, for each element, component selection corresponding to overcurrent due to miswiring, etc. There is no need to perform the process, which increases the degree of freedom in selecting parts. In addition, by providing a current limiting circuit, it is not necessary to increase the current limiting resistors 22 and 32 provided on the communication path in order to cope with an overcurrent due to erroneous wiring or the like, and it is possible to reduce or eliminate the resistance. It is.

  Further, regarding the problem that the receiving element of the transmission / reception circuit erroneously receives due to the induced voltage generated between the shared line N and the communication line S, the current limiting circuits 44 and 54 are responsible for dealing with the erroneous wiring. Therefore, the size of the current limiting resistors 22 and 32 may be sufficient if only the induced voltage can be handled. Therefore, it is only necessary to consider such points as reducing the impedance of the entire communication path to suppress the generation of the induced voltage, and the selection range is expanded when selecting the current limiting resistors 22 and 32.

  In addition, when a plurality of indoor units are connected to two outdoor units, so-called multi-configuration, more current flows on the communication path in consideration of communication control from the outdoor unit to the indoor unit. Therefore, it is advantageous if the current limiting resistance on the outdoor unit side can be reduced. .

  As described above, by providing a current limiting circuit on the communication path, not only can the elements on the communication path be reliably protected from overcurrent caused by miswiring or the like, but also the air conditioner that can exhibit the various effects described above. A communication control device can be provided.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the following embodiments, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description of the same components is omitted because it is duplicated.

  The second embodiment is characterized in that the DC power source provided for the current limiting circuit is used in common with the DC power source for communication provided in advance in the outdoor unit and / or indoor unit.

  That is, as shown in FIG. 2, the current limiting circuits 44 and 54 in the second embodiment are provided on the communication path 6 and in advance on the outdoor unit 2 side and the indoor unit 3 side, respectively. , 51 are also used as bias power supplies for the first transistors 24a, 34a. As a result, it is not necessary to provide a new DC power supply for the current limiting circuit, and the number of parts can be reduced.

  The first transistor 24a and the second transistor 24b incorporated in the current limiting circuit 44 in the second embodiment are both NPN type. On the other hand, in the current limiting circuit 34 on the indoor unit 3 side, both the first transistor 34a and the second transistor 34b are PNP type, but the operation is the same.

  With this configuration, in addition to the effects of the first embodiment described above, it is possible to reduce the number of components that constitute the current limiting circuit, and to provide a communication controller for an air conditioner that is lower in cost.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the following embodiments, the same components as those described in the first or second embodiment are denoted by the same reference numerals, and the description of the same components is omitted because it is duplicated. .

  In the third embodiment, one end of the outputs of the DC power sources 24c and 34c of the current limiting circuits 64 and 74 is connected to the bases of the first transistors 24a and 34a via the second current limiting resistors 24e and 34e. The transistors 24b and 34b are connected to a connection portion with the collector, and the other is connected to the communication path 6 with the transmission / reception circuits 21 and 31 interposed therebetween.

  In this way, by sandwiching the transmission / reception circuits 21 and 31 between the output paths of the DC power supplies 24c and 34c, the current limiting circuits 64 and 74 operate due to miswiring to limit the current of the communication path 6, and then the transmission elements 21a, If 31a is turned OFF, the outputs of the DC power sources 24c and 34c are cut off. As a result, the base currents of the first transistors 24a and 34a disappear, the first transistors 24a and 34a are turned off, and the communication path 6 itself is disconnected. At this time, all of the first transistors 24a and 34a and the second transistors 24b and 34b are turned off and no current flows, so that power consumption and heat generation in these transistors are eliminated.

  Therefore, if the transmission elements 21a and 31a are turned off in a short time after the current limiting circuits 64 and 74 limit the current, elements having low allowable collector loss are used as the first transistors 24a and 34a and the second transistors 24b and 34b. It can also be used.

  The first transistor 24a and the second transistor 24b incorporated in the current limiting circuit 24 in the third embodiment are both NPN type. On the other hand, in the current limiting circuit 34 on the indoor unit 3 side, both the first transistor 34a and the second transistor 34b are PNP type.

  As described above, in the third embodiment, all the effects of the first embodiment described above can be obtained, and the transmission element is controlled when an overcurrent flows in the communication path due to miswiring. As a result, the current can be finally cut off, and heat generation and deterioration of each element constituting the current limiting circuit can be avoided. In addition, it is not necessary to use a highly durable element on the assumption that an overcurrent flows, and the degree of freedom of component selection is increased.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. For example, the current limiting circuit can be configured by combining the configuration described in the second embodiment and the configuration described in the third embodiment. Also, a composite FET or a low current diode can be used as the transistor.

  Furthermore, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine the component covering different embodiment suitably.

It is explanatory drawing which shows simply the structure of the communication control apparatus in the air conditioner which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows simply the structure of the communication control apparatus in the air conditioner which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows simply the structure of the communication control apparatus in the air conditioner which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows simply the structure of the communication control apparatus in the conventional air conditioner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Communication control apparatus, 2 ... Indoor unit 3 ... Indoor unit, 4 ... Transition part, 5 ... AC power supply, 6 ... Communication path, 21 ... Outdoor unit side transmission / reception circuit, 21a ... Transmission element, 21b ... Reception element, 22 ... Current limiting resistor, 23 ... Diode, 24 ... Current limiting circuit, 24a ... First transistor, 24b ... Second transistor, 24c ... DC power source, 24d ... First current limiting resistor, 24e ... Second current limiting Resistor 31 ... Transmitting / receiving circuit on indoor unit side, 31a ... Transmitting element, 31b ... Receiving element, 32 ... Current limiting resistor, 33 ... Diode, 34 ... Current limiting circuit, 34a ... First transistor, 34b ... Second transistor , 34c: DC power supply, 34d: first current limiting resistor, 34e: second current limiting resistor

Claims (3)

A signal for operation control performed between the outdoor unit and the indoor unit, comprising an outdoor unit, an indoor unit connected to the outdoor unit with two AC power supply lines and one communication line The transmission unit uses one of the AC power supply lines as a shared line, and the outdoor unit and the indoor unit are connected in series to a communication path formed by the communication line and the shared line, respectively. In an air conditioner communication control apparatus comprising:
At least one of the outdoor unit and the indoor unit includes a current limiting circuit connected in series to the communication path.   The current limiting circuit includes a first transistor having an emitter and a collector connected in the middle of the communication path, a resistor inserted in the middle of the communication path, and a communication DC power source connected to the base of the first transistor. And a second transistor having a base connected between the first transistor and the resistor, an emitter connected to the other end of the resistor, and a collector connected to the base of the first transistor. The communication control device for an air conditioner according to claim 1, wherein   The output of the DC power supply for communication is such that one end is connected to the base of the first transistor and the other end is connected to the communication path across the transmission circuit provided on the communication path. The communication control device for an air conditioner according to claim 2, wherein the communication control device is an air conditioner.

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