JP5652489B2 - Power control board for refrigeration equipment - Google Patents

Description

  The present invention relates to a power control board of a refrigeration apparatus.

  A refrigeration apparatus such as an air conditioner is provided with various devices such as a compressor and a fan. A motor is often used as a drive source for these devices. The motor is driven by electric power supplied from a commercial power source.

  By the way, in the refrigeration apparatus, when any abnormality occurs in the refrigeration apparatus including the abnormality of the above devices, the control of stopping the operation of the refrigeration apparatus is performed, and a configuration for detecting the presence or absence of the abnormality related to the refrigeration apparatus is adopted. ing. An example of this is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 11-83211). The refrigeration apparatus according to Patent Document 1 is provided with a high-pressure switch that operates when the refrigerant pressure exceeds a predetermined value as a high-pressure protection control mechanism for preventing the occurrence of problems due to an abnormal increase in the high-pressure side pressure. When the high-voltage switch operates, the power switch between the commercial power source and the motor is turned off, and the power supply to the motor is cut off.

  However, in Patent Document 1, many elements are used in addition to a semiconductor element such as a photocoupler as a mechanism for turning off a power switch by operating a high-voltage switch. For this reason, in Patent Document 1, the elements constituting the mechanism are expensive, and the number of elements inevitably increases. Therefore, in Patent Document 1, the structure itself of the mechanism for turning off the power switch is complicated by the operation of the high-voltage switch, and the cost is increased as a whole.

  Therefore, an object of the present invention is to provide a power control board for a refrigeration apparatus that can reliably cut off power supply to a motor by an inexpensive and simple method.

The power control board of the refrigeration apparatus according to the first aspect of the present invention includes a plurality of connection units, a plurality of abnormality detection switches, a state change switch, a leakage current switch, and a control unit . The plurality of connection portions are connected to a plurality of inverter boards. A power switch and an inverter are mounted on each inverter board. The power switch turns on / off the power supply to the motor. The motor is a drive source for equipment included in the refrigeration apparatus. The inverter outputs a drive voltage to the motor. Each abnormality detection switch takes an off state when there is an abnormality relating to the refrigeration apparatus, and takes an on state when there is no abnormality relating to the refrigeration apparatus. The state change switch is electrically connected to the power switch of each inverter board via each connection portion. The state change switch is turned on / off in accordance with on / off of the abnormality detection switch, thereby changing the power switch to the on state or the off state. The leakage current switch can turn on / off the state change switch based on the value of the leakage current in the device included in the motor or the refrigeration apparatus. The control unit controls the drive voltage output operation for the inverter. When at least one of the plurality of abnormality detection switches is turned off from the on state, or when the leakage current switch is turned from the on state to the off state when the value of the leakage current is higher than the reference value, The state change switch changes the power switches of all the plurality of inverter boards from the on state to the off state. The control unit outputs the drive voltage to the inverters on all the plurality of inverter boards while the power switch is turned off after at least one of the plurality of abnormality detection switches and the leakage current switch is turned off. Stop.

  Here, examples of the abnormality related to the refrigeration apparatus include an abnormality in the pressure of a compressor included in the refrigeration apparatus, an abnormality in the refrigeration apparatus itself such as an operation abnormality of the refrigeration apparatus, and the like. According to this power control board, when at least one abnormality detection switch changes from an on state to an off state, the state change switch changes from on to off in conjunction with the change in the state of the abnormality detection switch. The power switch changes from an on state to an off state. Thereby, even when at least one abnormality detection switch detects an abnormality related to the refrigeration apparatus, the power supply to all the motors is cut off. Therefore, the power supply to the motor can be reliably cut off by an inexpensive and simple method.

  Further, according to the power control board, the state change switch is turned on / off not only by the abnormality detection switch but also by a leakage current switch that is turned on / off based on the leakage current. As a result, for example, an abnormality has occurred in the motor and leakage current is flowing, but even if the abnormality detection switch cannot detect the leakage current as abnormal, all the state change switches are turned off by the leakage current switch, The inverters on all the inverter boards stop driving voltage output. Therefore, the power supplied to all the motors can be shut off more reliably.

  The power control board of the refrigeration apparatus according to the second aspect of the present invention further includes a delay unit in the power control board of the refrigeration apparatus according to the first aspect. The delay unit delays the timing at which the state change switch changes from the on state to the off state so that the power switch changes from the on state to the off state after the abnormality detection switch changes from the on state to the off state. .

  According to the delay part of this power control board, the abnormality detection switch does not change from the on state to the off state at the same time as the abnormality detection switch changes from the on state to the off state. After changing to the off state, the state change switch changes from the on state to the off state. Thereby, the power control board can send, for example, an abnormality detection signal to the inverter board before the power switch is turned off. Therefore, the inverter on the inverter board can stop the output of the drive voltage to the motor before the power switch is turned off. Therefore, it is possible to prevent welding from occurring in the transistor and the power switch constituting the inverter.

  In the power control board of the refrigeration apparatus according to the third aspect of the present invention, a voltage lower than about 30 V is applied to the abnormality detection switch in the power control board of the refrigeration apparatus according to the first aspect or the second aspect. .

  This power control board employs a so-called weak electric circuit configuration in which a voltage lower than about 30 V is applied to the abnormality detection switch. Accordingly, it is possible to use a low-power capacitor having a relatively low breakdown voltage, particularly as the delay unit described above.

  The power control board of the refrigeration apparatus according to the fourth aspect of the present invention is the power control board of the refrigeration apparatus according to the first to third aspects. The state change switch is in series with the state change relay switch and the abnormality detection switch. It is comprised with the relay coil for a state change connected to. The power control board further includes a backflow prevention unit. The backflow prevention unit is connected in parallel or in series to the state change relay coil, and the current caused by the back electromotive force generated in the state change relay coil flows backward when the abnormality detection switch changes from the on state to the off state. To prevent.

  According to this power control board, even if a back electromotive force is generated in the state change relay coil when the abnormality detection switch changes from the on state to the off state, the back flow prevention unit prevents the back flow of the current due to the back electromotive force. Can be removed. Therefore, it is possible to prevent the elements mounted on the power control board from being destroyed by the backflow of the current accompanying the back electromotive force generated in the state change relay coil.

  The power control board of the refrigeration apparatus according to the fifth aspect of the present invention is the power control board of the refrigeration apparatus according to the first to fourth aspects. The power switch includes a power relay coil and a power relay switch. The power supply relay coil is electrically connected in series with the state change switch. The power relay switch is arranged between the commercial power source and the motor. A coil power switch is further mounted on each inverter board. The coil power switch is connected in series to the power supply relay coil, and turns on / off the power supply to the power supply relay coil. Then, the power supply relay switch is turned off based on the voltage across the power supply relay coil when the state change switch is turned off or the coil power switch is turned off.

  In the inverter board connected to the power control board, the power switch supplies power from the commercial power source to the motor depending on the state that the state change switch can take or the coil power switch that is different from the state change switch. Cut off. Here, the coil power switch can be a switch that can turn off the power switch when, for example, the refrigeration apparatus is normal and normal. Thereby, also about an inverter board | substrate, the power supply supplied to a motor can be reliably interrupted | blocked with a simple structure, both when a refrigeration apparatus is normal and when there exists abnormality.

  The power control board of the refrigeration apparatus according to the first aspect of the present invention can reliably cut off the power supply to the motor by an inexpensive and simple method. Moreover, the power control board can more reliably cut off the power supplied to all the motors.

  In the power control board of the refrigeration apparatus according to the second aspect of the present invention, the inverter of the inverter board can stop the output of the drive voltage to the motor before the power switch is turned off. Therefore, it is possible to prevent welding from occurring in the transistor and the power switch constituting the inverter.

  According to the power control board of the refrigeration apparatus according to the third aspect of the present invention, it is possible to use a low-power capacitor having a relatively low withstand voltage as the delay unit according to the second aspect.

  In the power control board of the refrigeration apparatus according to the fourth aspect of the present invention, the elements mounted on the power control board are destroyed by the backflow of current accompanying the back electromotive force generated in the state change relay coil. Can be prevented.

  The inverter board connected to the power control board of the refrigeration apparatus according to the fifth aspect of the present invention also has a simple configuration and reliably supplies the motor regardless of whether the refrigeration apparatus is normal or abnormal. Can be shut off.

The block diagram of the motor drive system which concerns on this embodiment. The figure which shows schematically the circuit structure mounted in the power control board which concerns on this embodiment. The figure which shows schematically the circuit structure mounted in the inverter board | substrate which concerns on this embodiment. The figure which shows schematically the circuit structure of an inverter part. The flowchart which shows the flow of operation | movement (especially at the time of abnormality) in a power control board and each inverter board | substrate. The flowchart which shows the flow of operation | movement (especially at the time of normal) in a power control board and each inverter board | substrate. The timing chart which shows an example of operation | movement of each switch and circuit on an electric power control board | substrate and each inverter board | substrate when abnormality regarding the air conditioning apparatus has not arisen. The timing chart which shows an example of operation | movement of each switch and circuit on a power control board and each inverter board | substrate when abnormality arises in one compressor among three. The figure which shows schematically the circuit structure mounted in the electric power control board | substrate which concerns on the modification B. The figure which shows schematically the circuit structure mounted in the inverter board | substrate which concerns on the modification F. FIG. The figure which shows schematically the circuit structure mounted in the inverter board | substrate which concerns on the modification F. FIG.

  Hereinafter, the power control board of the refrigeration apparatus according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
(1) Overall Configuration FIG. 1 is a configuration diagram of a motor drive system 101 including a power control board P1 according to an embodiment of the present invention. The motor drive system 101 includes a plurality of motors M21A, M21B, M21C, a plurality of inverter boards P21A, P21B, P21C, and one power control board P1.

  Here, the motors M21A to M21C will be described. The motors M21A to M21C are driving sources of a compressor provided in an outdoor unit of an air conditioner that is an example of a refrigeration apparatus, and may be, for example, a three-phase brushless DC motor. Although not shown, the motors M21A to M21C include a stator composed of a plurality of drive coils, a rotor composed of permanent magnets, a hall element for detecting the position of the rotor relative to the stator, and the like. Yes.

  In particular, in the motor drive system 101 according to the present embodiment, a case in which one outdoor unit is connected to a plurality of indoor units via a refrigerant pipe is taken as an example. Accordingly, a single outdoor unit is provided with a plurality of compressors, and the motor drive system 101 is provided with a plurality of motors M21A to M21C corresponding to each of the plurality of compressors. In the present embodiment, the number of compressors is three, and therefore the case where there are also three motors M21A to M21C is taken as an example.

  The inverter boards P21A to P21C are boards for driving the motors M21A to M21C, and three inverter boards P21A to P21C are provided in the system 101 according to the number of the motors M21A to M21C. Each inverter board | substrate P21A-P21C is electrically connected with each corresponding motor M21A-M21C via the harness. The power control board P1 is a board that controls the supply and cut-off of power from the commercial power supply to the inverter boards P21A to P21C, and is electrically connected to the inverter boards P21A to P21C via a harness.

(2) Detailed Configuration Hereinafter, a circuit configuration mounted on each substrate will be described in detail.

(2-1) Power Control Board FIG. 2 is a diagram schematically showing a circuit configuration mounted on the power control board P1. As shown in FIG. 2, the power control board P1 mainly includes three first interfaces 11a, 11b, and 11c (corresponding to connection portions), three abnormality detection switches S11, S12, and S13, a leakage current detection circuit 14, and 1 One leakage current switch S14, three state change switches S15, S16, S17, one delay countermeasure capacitor C11 (corresponding to a delay unit), two backflow prevention diodes D11, D12 (corresponding to a backflow prevention unit), and Three second interfaces 18a, 18b, and 18c are provided.

(2-1-1) First Interface The first interfaces 11a to 11c are for electrically connecting the power control board P1 to the inverter boards P21A to P21C, and are on one power control board P1. There are three. That is, since the motor drive system 101 of this embodiment includes three inverter boards P21A to P21C, three first interfaces 11a to 11c are also provided corresponding to the number of inverter boards P21A to P21C. ing. The first interfaces 11a to 11c are configured by connectors to which tip portions of two harnesses extending from the respective inverter boards P21A to P21C are connected, and are electrically connected to state change switches S15 to S17 described later by wiring. Has been.

(2-1-2) Abnormality detection switch The three abnormality detection switches S11 to S13 are connected in series via sockets S11a, S12a, and S13a provided on a power line L11 of about 16V. Three abnormality detection switches S11 to S13 are provided corresponding to the number of compressors of the outdoor unit, and detect abnormality of each corresponding compressor. Specifically, the pressure of the refrigerant after being compressed by the corresponding compressor is out of the normal pressure range due to some cause relating to the compressor, and is in a high pressure state higher than a predetermined value on the high pressure side of the pressure range. In this case, the abnormality detection switches S11 to S13 operate to change the state of the switch itself. That is, the abnormality detection switches S11 to S13 according to the present embodiment are high pressure switches (that is, HPS: High Pressure Switch).

  Here, in the present embodiment, normally closed contacts are employed as the abnormality detection switches S11 to S13. That is, each abnormality detection switch S11-S13 takes an ON state when there is no abnormality in the corresponding compressor (that is, when it is normal). On the contrary, each abnormality detection switch S11-S13 takes an OFF state when there is an abnormality in the corresponding compressor. In particular, a voltage lower than about 30 V (here, about 16 V) is applied to the abnormality detection switches S <b> 11 to S <b> 13 in the present embodiment as a weak electric voltage.

  Accordingly, if there is an abnormality in at least one of the three compressors, at least one of the abnormality detection switches S11 to S13 connected in series is turned off, so that the power line L11 of about 16V in FIG. It will be blocked.

  The voltage of about 16 V applied to the power supply line L11 is generated by a switching power supply (not shown) that is also mounted on the power control board P1.

(2-1-3) Leakage Current Detection Circuit and Leakage Current Switch The leakage current detection circuit 14 includes a comparator and the like. The leakage current detection circuit 14 receives various signals from the motors M21A to M21C or the compressor, and detects the value of the leakage current in the motors M21A to M21C or the compressor based on these signals. The value of the leakage current detected by the leakage current detection circuit 14 is output to the leakage current switch S14.

  The leakage current switch S14 is composed of a Pch bipolar transistor, and is connected in series between the abnormality detection switches S11 to S13 and the resistor R13 located on the GND side. Specifically, the emitter of the leakage current switch S14 is connected to the abnormality detection switch S13, the base is connected to the output of the leakage current detection circuit 14, and the collector is connected to the resistor R11. Hereinafter, for convenience of explanation, a connection portion between the collector of the leakage current switch S14 and the resistor R11 is referred to as a “connection point sa”.

  When the leakage current detection circuit 14 detects leakage current in the motors M21A to M21C or the compressor, the leakage current switch S14 is turned on or off based on the value of the current. Specifically, when the leakage current is higher than the reference value, the leakage current detection circuit 14 outputs a voltage of about 16 V (ie, “H”) that turns off the leakage current switch S14. The leakage current switch S14 is turned off. On the other hand, when the leakage current is lower than the reference value, the leakage current detection circuit 14 outputs a voltage of about 0 V (that is, “L”) that turns on the leakage current switch S14. The current switch S14 is turned on.

  Therefore, in the power control board P1 according to the present embodiment, the power line L11 of about 16V in FIG. 2 is cut off not only by detecting the compressor abnormality by the abnormality detection switches S11 to S13 but also by detecting the leakage current. It will be. In particular, even when the abnormality detection switches S11 to S13 are out of order and the abnormality cannot be detected, the power line L11 of about 16V is cut off by the detection result of the leakage current, so it can be said that the safety is increased.

(2-1-4) State Change Switch The state change switches S15 to S17 are electrically connected to the power switch 22 (see FIG. 3) of each inverter board P21A to P21C via each of the first interfaces 11a to 11c. . The state change switches S15 to S17 are turned on / off according to the on / off of the abnormality detection switches S11 to S13, thereby changing the power switch 22 of each inverter board P21A to P21C to an on state or an off state. In other words, the state change switches S15 to S17 take an on state or an off state in conjunction with the operation of the abnormality detection switches S11 to S13.

  Each of the state change switches S15 to S17 includes one relay coil S15a, S16a, S17a (corresponding to a state change relay coil) and one relay switch S15b, S16b, S17b (corresponding to a state change relay switch). Yes. The relay coils S15a to S17a are connected in parallel to each other. Each relay coil S15a to S17a has one end connected in series to the abnormality detection switches S11 to S13 via a connection point sa, and the other end connected to GND. The relay switches S15b to S17b can individually be turned on / off based on the voltage across the corresponding relay coils S15a to S17a. Specifically, each of the relay switches S15b to S17b is in an ON state when a voltage is applied to both ends of the corresponding relay coils S15a to S17a, and a voltage is applied to both ends of the corresponding relay coils S15a to S17a. If not, the off state is taken.

  According to such state change switches S15 to S17, when all of the abnormality detection switches S11 to S13 and the leakage current switch S14 are turned on, one end of each of the relay coils S15a to S17a is connected to about 16V via the power line L11. Is applied, and GND is applied to the other end. For this reason, it will be in the state in which the voltage is applied to the both ends of each relay coil S15a-S17a, and each relay switch S15b-S17b will take an ON state. In this case, the power switch 22 on each of the inverter boards P21A to P21C that are electrically connected also takes an on state. Conversely, when at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 is off, the power supply line L11 is cut off. Therefore, a voltage of about 16 V is not applied to each of the relay coils S15a to S17a, and no voltage is applied to both ends of each of the relay coils S15a to S17a. Therefore, the relay switches S15b to S17b are in the off state. In this case, the power switches 22 on the inverter boards P21A to P21C that are electrically connected also take off.

  In summary, the state change switches S15 to S17 according to the present embodiment turn on the power switches 22 of all the inverter boards P21A to P21C when all the switches S11 to S14 connected to the power line L11 are turned on. To. Conversely, when at least one of the switches S11 to S14 connected to the power supply line L11 changes from the on state to the off state, the state change switches S15 to S17 correspond to the abnormality detection switches S11 to S13 that have changed to the off state. In addition to the inverter boards P21A to P21C, the power switches 22 of all the inverter boards P21A to P21C are turned off. In other words, if any one of the compressors is abnormal, the drive of all three compressors is stopped in order to maintain more reliable safety rather than stopping only the abnormal compressor. The

  In particular, in the present embodiment, the number of state change switches S15 to S17 is not one but three according to the number of inverter boards P21A to P21C. The on / off states of the state change switches S15 to S17, that is, the on / off states of the abnormality detection switches S11 to S13, are sent to the inverter boards P21A to P21C via the first interfaces 11a to 11c. It is done. With this configuration, it is possible to cope with cases where the corresponding voltages of the inverter boards P21A to P21C are different.

(2-1-5) Delay Countermeasure Capacitor The delay countermeasure capacitor C11 has one end connected to the connection point sa and the other end connected to the GND side. The delay countermeasure capacitor C11 is connected in parallel to the relay coils S15a to S17a.

  When all of the abnormality detection switches S11 to S13 and the leakage current switch S14 are on, about 16 V is applied to the delay countermeasure capacitor C11 via the power supply line L11. Therefore, a charge corresponding to the capacitance of the capacitor C11 and the applied voltage (about 16 V) is accumulated in the delay countermeasure capacitor C11 and charged.

  Thereafter, when at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 is turned off, the voltage application of about 16V from the power supply line L11 is applied not only to the relay coils S15a to S17a but also to the delay countermeasure capacitor C11. Blocked. However, a voltage associated with the electric charge charged in the delay countermeasure capacitor C11 is applied to both ends of each of the relay coils S15a to S17a. As a result, the delay countermeasure capacitor C11 discharges the accumulated charges, and the relay switches S15b to S17b continue to be turned on until the amount of charge discharged from the delay countermeasure capacitor C11 is equal to or less than a predetermined amount.

  Therefore, even if the power supply line L11 is cut off because at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 changes from the on state to the off state, all the relay switches S15b to S17b are immediately turned off. The relay switches S15b to S17b are all delayed from changing from the on state to the off state due to the charge accumulated in the delay countermeasure capacitor C11. As already described, since the state change switches S15 to S17 and the power switch 22 of each inverter board P21A to P21C are linked, the delay countermeasure capacitor C11 is switched from the on state to the off state. It plays the role of delaying the timing. That is, in the delay countermeasure capacitor C11, after the abnormality detection switches S11 to S13 change from the on state to the off state, the power switch 22 on each inverter board P21A to P21C side changes from the on state to the off state. Thus, it can be said that this is for delaying the timing at which the state change switches S15 to S17 change from the on state to the off state.

  Here, after at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 that are all turned on is turned off, the power switch 22 of each inverter board P21A to P21C is turned from on to off. The delay time until the change can be adjusted by the capacitance of the delay countermeasure capacitor C11. The capacitance of the delay countermeasure capacitor C11 that is actually used is appropriately determined by desktop calculation, simulation, or experiment based on a desired delay time and a voltage (about 16 V in this case) applied to the power supply line L11. For example, when the delay time is desired to be about 38 msec or longer (for example, 47 msec), an electrolytic capacitor having a capacitance of about 330 μF to 470 μF can be used as the delay countermeasure capacitor C11.

  In the present embodiment, the desired delay time refers to each of the inverter boards P21A to P21C after the abnormality detection switches S11 to S13 detect abnormality of the compressor or the leakage current switch S14 is turned off due to the leakage current. The time required for the inverter MPU 21 (described later) to stop outputting the drive voltages SU, SV, SW to the motors M21A to M21C based on the voltage value at the connection point sa.

  Moreover, as a kind of capacitor | condenser utilized as the capacitor | condenser C11 for delay measures, a tantalum capacitor, a ceramic capacitor, etc. other than an electrolytic capacitor are mentioned. In addition, since a voltage of about 16 V is applied to the delay countermeasure capacitor C11 according to the present embodiment at the maximum, it is possible to use a capacitor with a relatively low power specification and to reduce the cost.

(2-1-6) Backflow Prevention Diode The backflow prevention diode D11 is connected between the abnormality detection switches S11 to S13 and the state change switches S15 to S17. Specifically, the anode side of the backflow prevention diode D11 is connected to the connection point sa, and the cathode side is connected to the connection point sb between the delay countermeasure capacitor C11 and the relay coils S15a to S17a. That is, the backflow prevention diode D11 is connected in series to the relay coils S15a to S17a.

  The anode side of the backflow prevention diode D12 is connected to GND, and the cathode side is connected to the connection point sb. That is, the backflow prevention diode D12 is connected in parallel to the delay countermeasure capacitor C11 and the relay coils S15a to S17a.

  These backflow prevention diodes D11 and D12 allow a current to flow from the anode side to the cathode side when a voltage higher than a predetermined voltage is applied, and from the anode side when a voltage higher than the predetermined voltage is not applied. Cut off the current flow to the cathode side.

  In other words, when all of the abnormality detection switches S11 to S13 and the leakage current switch S14 are turned on, the backflow prevention diode D11 is applied with a voltage of about 16V that is equal to or higher than a predetermined voltage (for example, 0.7V) on the anode side. Therefore, the flow of current from the connection point sa to the state change switches S15 to S17 is allowed. However, when at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 is off, the GND voltage “about 0V” is applied to the anode side of the backflow prevention diode D11 via the resistor R11. The positive side voltage of the delay countermeasure capacitor C11 is applied to the cathode side. Accordingly, the voltage on the cathode side is higher than the voltage on the anode side of the backflow prevention diode D11, and no current flows from the connection point sa to the state change switches S15 to S17.

  Further, when all of the abnormality detection switches S11 to S13 and the leakage current switch S14 are turned on, the backflow prevention diode D12 is applied with a voltage of about 16V on the cathode side and a GND voltage “about 0V on the anode side. "Is applied. Therefore, the voltage on the cathode side of the backflow prevention diode D12 becomes higher than the voltage on the anode side, and the diode D11 is turned off. When at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 is off, the backflow prevention diode D12 is such that the voltage across the relay coils S15a to S17a is less than or equal to a predetermined voltage (for example, about 0.7V). If it is present, it is not turned on, but if the voltage across the relay coils S15a to S17a is equal to or higher than a predetermined voltage, it is turned on so that no current flows from the anode side to the cathode side.

  In particular, when at least one of the switches S11 to S14 on the power supply line L11 changes from the on state to the off state, the state of the voltage across the relay coils S15a to S17a changes according to the discharge of the delay countermeasure capacitor C11. A back electromotive force is generated. However, the current due to the back electromotive force does not flow from the connection point sb side to the connection point sa side by the backflow prevention diode D11, and does not flow to the GND through the diode D12 by the backflow prevention diode D12. That is, the backflow prevention diodes D11 and D12 are generated in the relay coils S15a to S17a when the switches S11 to S14 (for example, the abnormality detection switches S11 to S13) on the power supply line L11 change from the on state to the off state. It plays a role to prevent current backflow due to back electromotive force.

(2-1-7) Second Interface The second interfaces 18a to 18c are for electrically connecting the power control board P1 to the inverter boards P21A to P21C, like the first interfaces 11a to 11c. Three are provided on one power control board P1. The second interfaces 18a to 18c are connectors so as to be connected to the tip portions of one harness extending from the inverter boards P21A to P21C separately from the harnesses between the first interfaces 11a to 11c and the inverter boards P21A to P21C. It is configured. The second interfaces 18a to 18c are interfaces between the power control board P1 and the inverter boards P21A to P21C for transmitting the voltage value of the connection point sa to the inverter boards P21A to P21C.

  The voltage value of the connection point sa is a value based on the on / off states of the abnormality detection switches S11 to S13 and the leakage current switch S14. Specifically, when there is an abnormality in the compressor and no leakage current has occurred in the compressors or motors M21A to M21C, the abnormality detection switches S11 to S13 and the leakage current switch S14 are all on, so the connection point The voltage value of sa is “about 16V”. When at least one of the abnormality in the compressor and the leakage current in the compressor and the motors M21A to M21C occurs, at least one of the abnormality detection switches S11 to S13 and the leakage current switch S14 is turned off. The voltage value of is about "0V". Thus, it can be said that the voltage value of the connection point sa is an abnormal signal indicating the presence or absence of an abnormality in the air conditioner, including the presence or absence of an abnormality in each compressor and the presence or absence of a leakage current.

(2-2) Inverter Board FIG. 3 is a diagram schematically showing a circuit configuration mounted on the inverter boards P21A to P21C according to the present embodiment. Here, in the present embodiment, the three inverter boards P21A to P21C all have the same circuit configuration. For this reason, in FIG. 3, the detailed configuration of each of the inverter boards P21A to P21C is not given a different reference for each inverter board P21A to P21C, but is given the same reference numeral.

  As shown in FIG. 3, the inverter boards P <b> 21 </ b> A to P <b> 21 </ b> C mainly include an inverter MPU 21, a power switch 22, a switch control circuit 23, and an abnormality detection circuit 25.

(2-2-1) MPU for inverter
The inverter MPU 21 is connected to the corresponding motors M21A to M21C via connectors IF21A, IF21B, and IF21C (see FIG. 4). The inverter MPU 21 is also connected to one end of the power switch 22, the output of the abnormality detection circuit 25, and the input of the switch control circuit 23. The inverter MPU 21 is a semiconductor chip that receives electric power from the commercial power supply 51 and performs drive control of the motor, and mainly functions as the inverter unit 21a and the voltage application control unit 21b.

  The inverter unit 21a drives the motors M21A to M21C by outputting three-phase drive voltages SU to SW to the connected motors M21A to M21C. Specifically, as shown in FIG. 4, the inverter unit 21a includes a plurality of insulated gate bipolar transistors Q31a, Q31b, Q32a, Q32b, Q33a, Q33b (hereinafter simply referred to as transistors) and a plurality of freewheeling diodes D31a, D31b. , D32a, D32b, D33a, D33b, and a gate control unit 34. Transistors Q31a and Q31b, Q32a and Q32b, and Q33a and Q33b are connected in series to each other, and the diodes D31a to D33b are connected in parallel to the transistors Q31a to Q33b. The gate controller 34 is connected to the gates of the transistors Q31a to Q33b, and controls the application of the gate voltage to the transistors Q31a to Q33b, thereby turning on and off the transistors Q31a to Q33b. Such an inverter unit 21a generates drive voltages SU to SW for driving the motors M21A to M21C by turning on and off the transistors Q31a to Q33b at a predetermined timing, and the voltages SU to SW are generated. Output to the corresponding motors M21A to M21C. The motors M21A to M21C can rotate by the drive voltages SU to SW.

  In particular, the inverter unit 21a outputs the drive voltages SU to SW or stops the output based on the voltage value of the connection point sa sent via the second interfaces 18a to 18c of the power control board P1. can do. Specifically, when the voltage value of the connection point sa is about 16 V indicating that all the switches S11 to S14 are turned on, the inverter unit 21a is supplied with power via the power switch 22. As long as the drive voltages SU to SW are output to the motors M21A to M21C. On the contrary, when the voltage value of the connection point sa is lower than about 16V, it is determined that at least one of the switches S11 to S14 is turned off because of the abnormality of the compressor or the leakage current, and the inverter unit 21a stops the output of the drive voltages SU to SW even if the power is still supplied through the power switch 22. When the output of the drive voltages SU to SW is stopped, the gate control unit 34 outputs “about 0 V” to the gates of all the transistors Q31a to Q33b, so that all the transistors Q31a to Q33b are output. Turn off.

  As shown in FIG. 3, the voltage application control unit 21 b controls on / off of the coil power switch 23 a on the switch control circuit 23. The voltage application control unit 21b performs on / off of the coil power switch 23a based on the result of the abnormality detection of the air conditioner by the abnormality detection circuit 25, and the air conditioner itself is normal and has no abnormality. Even in some cases, it is based on thermo-on / thermo-off. Specifically, the voltage application control unit 21b turns off the coil power switch 23a when an abnormality occurs in the air conditioner and when the thermostat should be turned off even if the air conditioner is normal. Conversely, the voltage application control unit 21b turns on the coil power switch 23a when the thermo-ON should be performed even if the air conditioner is normal. The instruction for thermo-on and thermo-off may be acquired by the inverter MPU 21 from a microcomputer (not shown) different from the MPU 21 or may be determined by the inverter MPU 21 itself. In the following, the case where the inverter MPU 21 acquires a thermo-on and thermo-off instruction from another microcomputer will be taken as an example.

(2-2-2) Power Switch The power switch 22 is for turning on / off the power supply to the motors M21A to M21C. The power switch 22 is composed of one relay coil 22a (corresponding to a power relay coil) and two relay switches 22b and 22c (corresponding to a power relay switch).

  The two relay switches 22b and 22c are both installed on the power supply line L21 between the commercial power supply 51 and the motors M21A to M21C. More specifically, one end of each relay switch 22b, 22c is connected to the commercial power source 51 via a connector (not shown) mounted on the inverter boards P21A to P21C, and the other end is connected to the inverter MPU 21. ing. The two relay switches 22b and 22c are not in different states but are in the same state. When the voltage across the relay coil 22a is equal to or higher than a predetermined voltage, both are in the on state. When both end voltages are equal to or lower than a predetermined voltage, both are turned off. That is, the relay switches 22b and 22c are turned on / off based on the value of the voltage across the relay coil 22a.

  Here, in the present embodiment, a case where the predetermined voltage that is a condition for turning on the relay switches 22b and 22c is “about 9 V” is taken as an example.

  The relay coil 22a will be described in the following “switch control circuit 23”.

(2-2-3) Switch Control Circuit The switch control circuit 23 is electrically connected to the inverter boards P21A to P21C via the connector 24 and the state change switches S15 to S17 on the power control board P1 side which are external contacts. Connected. The switch control circuit 23 turns on / off the power supply to the motors M21A to M21C by the power switch 22, that is, on / off of the relay switches 22b and 22c, based on the on or off state of the state change switches S15 to S17. To control. Specifically, the switch control circuit 23 turns on the relay switches 22b and 22c when the state change switches S15 to S17 are in the on state. Conversely, the switch control circuit 23 turns off the relay switches 22b and 22c when the state change switches S15 to S17 are in the off state.

  Such a switch control circuit 23 mainly includes a coil power switch 23a, a relay coil 22a, a diode 23c, and a capacitor 23d.

  The coil power switch 23a is composed of a Pch bipolar transistor. The coil power switch 23a has an emitter connected to a power source of about 15V, a base connected to the output of the voltage application controller 21b of the inverter MPU 21, and a collector connected to one end sc of the relay coil 22a via a resistor R23. The coil power switch 23a is turned on when approximately 0V (ie, output “L”) is applied to the base from the voltage application control unit 21b, and applies a voltage of approximately 15V to one end sc of the relay coil 22a. On the contrary, the coil power switch 23a is turned off when about 15V (ie, output “H”) is applied to the base from the voltage application control unit 21b, and a voltage of about 15V is not applied to one end sc of the relay coil 22a. Like that. That is, on / off of the coil power switch 23a is controlled by the voltage application control unit 21b, and the power supply to the relay coil 22a connected in series is turned on / off.

  One end sc of the relay coil 22a is connected in series to the resistor R23, and the other end sd is electrically connected to one end of the connector 24 for the state change switches S15 to S17 on the power control board P1. The other end sd of the relay coil 22 a is connected to GND via the other end of the connector 24. That is, the relay coil 22a is electrically connected in series via the state change switches S15 to S17 and the connector 24 on the power control board P1.

  When the state change switches S15 to S17 and the coil power switch 23a are both on, a voltage of about 15V is applied to one end sc and a voltage of about 0V is applied to the other end sd. Will be applied. In this case, the voltage difference between both ends of the relay coil 22a is about 15V, and the voltage difference exceeds about 9V which is a predetermined voltage. Therefore, both relay switches 22b and 22c are turned on. On the other hand, when at least one of the state change switches S15 to S17 and the coil power switch 23a is turned off, a voltage (specifically, approximately one of the end portions sc and sd of the relay coil 22a is applied). 15V and / or about 0V) is not applied, and the voltage difference across the relay coil 22a does not exceed about 9V. Therefore, both the relay switches 22b and 22c are turned off.

  That is, in this embodiment, the mechanism in which the state change switches S15 to S17 are turned off in accordance with the occurrence of the abnormality of the compressor and the abnormality of the air conditioner including the leakage current, and the air conditioner is normal but the coil power is turned off by the thermo-off. In any of the mechanisms in which the switch 23a is turned off, one relay coil 22a is commonly used to turn off the relay switches 22b and 22c.

  Both the diode 23c and the capacitor 23d are connected in parallel to the relay coil 22a. In particular, the anode of the diode 23c is connected to the end sd of the relay coil 22a so as to be on the GND side, and the cathode is connected to the end sc of the relay coil 22a so as to be on the power supply side of about 15V. The diode 23c is provided to prevent a back electromotive force from being generated in the relay coil 22a when any one of the coil power switch 23a and the state change switches S15 to S17 is changed from on to off, and to prevent a backflow of current accompanying the power. It has been. The capacitor 23d indicates that when the coil power switch 23a and / or the state change switches S15 to S17 change from on to off, the voltage is instantaneously increased by the relay coil 22a and a spike current flows on the switch control circuit 23. It plays a role of so-called snubber circuit to prevent.

  Note that the voltage of about 15 V applied to the switch control circuit 23 is generated by a switching power supply (not shown) mounted on each of the inverter boards P21A to P21C.

(2-2-4) Abnormality detection circuit The abnormality detection circuit 25 is used to detect the presence or absence of an abnormality in the air conditioner including a compressor abnormality or a leakage current, using the value of the voltage across the relay coil 22a. is there. The abnormality detection circuit 25 mainly includes a photocoupler 25a and two resistors R25a and R25b.

  The photocoupler 25a includes a light emitting diode 25aa that is a light projecting unit and an Nch phototransistor 25ab that is a light receiving unit. The anode of the light emitting diode 25aa is connected between the resistor R23 and the collector of the coil power switch 23a, and the cathode is connected between the end sd of the relay coil 22a and the state change switches S15 to S17 via the resistor R25a. ing. The phototransistor 25ab has a collector connected to a power supply of about 5V, an emitter connected to the GND via a resistor R25b, and a voltage input to the light emission of the light emitting diode 25aa. According to the photocoupler 25a, when both the coil power switch 23a and the state change switches S15 to S17 are turned on, and the voltage is applied to both ends of the relay coil 22a, the light emitting diode 25aa is turned on. And emits light. In this case, the phototransistor 25ab is turned on in response to light emission from the light emitting diode 25aa, and a voltage value “about 5V” indicating that there is no abnormality in the air conditioner is input to the voltage application control unit 21b of the inverter MPU 21. Is done. Conversely, when the coil power switch 23a and / or the state change switches S15 to S17 are turned off, the light emitting diode 25aa is turned off when no voltage is applied to both ends or one end of the relay coil 22a. . In this case, since the light emitting diode 25aa does not emit light, the phototransistor 25ab is turned off, and the voltage application control unit 21b of the inverter MPU 21 is input with a voltage value “about 0 V” indicating that the air conditioner is abnormal. The

  Note that a voltage of about 5 V applied to the phototransistor 25ab is generated by a switching power supply (not shown) mounted on each of the inverter boards P21A to P21C.

(3) Operation Next, the operation of each switch and the operation of the motor in the power control board P1 and the inverter boards P21A to P21C according to the present embodiment will be described.

(3-1) Flow of Operation FIGS. 5 and 6 are flowcharts showing the flow of operation in each of the substrates P1, P21A to P21C. When there is an abnormality in the air conditioner, there is no abnormality in the air conditioner. Shows the case. Here, first, it is assumed that all three compressors are normal, no leakage current is generated, and the air conditioner is operating in a thermo-on state. That is, it is assumed that the switches S11 to S17, 22, and 23a on the substrates P1, P21A to P21C are all on and the motors M21A to M21C are driven based on the drive voltages SU to SW.

  Steps sp1 to sp5: When an abnormality occurs in at least one of the three compressors corresponding to the abnormality detection switches S11 to S13 related to the power control board P1, and the switches S11 to S13 change from on to off (steps) Yes of sp1 to sp3), the voltage value of the connection point sa changes from about 16V to about 0V. Alternatively, even when the leakage current is detected by the leakage current detection circuit 14 related to the power control board P1 and the leakage current switch S14 is changed from on to off (Yes in step sp4), the voltage value of the connection point sa is It changes from about 16V to about 0V. As a result, the circuits on the abnormality detection switches S11 to S13 side from the backflow prevention diode D11 are disconnected from the circuits on the state change switches S15 to S17 side. A voltage according to the charge amount of the delay countermeasure capacitor C11 that has been charged is applied to each of the relay coils S15a to S17a related to the power control board P1, and the delay countermeasure capacitor C11 starts discharging (step sp5). ).

  Step sp6: On the other hand, the inverter unit 21a of the inverter MPU 21 related to each of the inverter boards P21A to P21C changes the voltage value of the connection point sa on the board P1 sent from the power control board P1 from about 16V to about 0V. In response to the change, the output of the drive voltages SU to SW to the motors M21A to M21C is stopped.

  Steps sp7 to sp8: The voltage values at both ends of each of the relay coils S15a to S17a related to the power control board P1 are about 16V immediately after at least one switch S11 to S14 is changed from on to off. As the capacitor C11 is discharged, it gradually decreases. When the discharge of the delay countermeasure capacitor C11 progresses and the voltage across the relay coils S15a to S17a of all the state change switches S15 to S17 becomes about 9 V or less (Yes in step sp7), all the state change switches S15 to S17 relays The switches S15b to S17b change from on to off (step sp8).

  Step sp9: On all inverter boards P21A to P21C, as the state change switches S15 to S17 on the power control board P1 change from on to off, the GND side of the relay coil 22a in the switch control circuit 23 The end sd is cut, and the end sd is in a “Hiz” state. Thereby, the relay switches 22b and 22c of the power switch 22 are changed from on to off. Further, the photocoupler 25a of the abnormality detection circuit 25 is also turned off, and a voltage value “about 0 V” indicating that there is an abnormality in the air conditioner is input from the abnormality detection circuit 25 to the inverter MPU 21. For this reason, the voltage application control unit 21b of the inverter MPU 21 applies a voltage of "about 5V" to the gate of the coil power switch 23a, and the switch 23a changes from on to off. By these operations, in the switch control circuit 23, both ends of the relay coil 22a (specifically, each end sc and sd side) are both disconnected from the power line side and the GND side of about 15V. .

  Steps sp10 to sp13: Further, in steps sp1 to sp4, when all of the abnormality detection switches S11 to S13 and the leakage current switch S14 on the power control board P1 side remain on (No in step sp4), power control is performed. All the state change switches S15 to S17 on the substrate P1 side remain on. In this case, each board | substrate P1, P21A-P21C performs the following operation | movement, assuming that an air conditioning apparatus is normal. That is, when each inverter MPU 21 obtains a thermo-off instruction from the outside (Yes in step sp10), the voltage application control unit 21b of the MPU 21 applies a voltage of about 5V to the gate of the coil power switch 23a. The switch 23a changes from on to off (step sp11). As a result, the end sc of the relay coil 22a in the switch control circuit 23 is disconnected, and the end sc is in a “Hiz” state in which no voltage is applied. Accordingly, the relay switches 22b and 22c of the power switch 22 change from on to off (step sp12), and the inverter unit 21a of the inverter MPU 21 stops outputting the drive voltages SU to SW to the motors M21A to M21C ( Step sp13).

  Steps sp14 to sp17: After step sp13, when each inverter MPU 21 obtains a thermo-on instruction from the outside (Yes in step sp14), the voltage application control unit 21b of the MPU 21 is connected to the gate of the coil power switch 23a. A voltage of about 0 V is applied, and the switch 23a changes from off to on (step sp15). As a result, the end sc of the relay coil 22a in the switch control circuit 23 is connected to the power line of about 15V, and a voltage difference of about 15V is generated at both ends of the relay coil 22a. Accordingly, the relay switches 22b and 22c of the power switch 22 change from off to on (step sp16), and the inverter unit 21a of the inverter MPU 21 outputs the drive voltages SU to SW to the motors M21A to M21C (steps). sp17).

(3-2) Specific Example (3-2-1) Normal Example FIG. 7 shows each of the substrates P1, P21A to P21C on the substrate P1, P21A to P21C when there is no abnormality in the air conditioner (that is, normal). It is a timing chart which shows an example of operation of a switch and a circuit.

  When the air conditioner is normal, all of the abnormality detection switches S11 to S13 and the leakage current switch S14 are kept on, so that the state change switches S15 to S17 are all kept on. That is, on the power control board P1 side, even if the inverter boards P21A to P21C obtain a thermo-on / thermo-off instruction from the outside, the state of each of the switches S11 to S17 does not change.

  However, as shown in FIG. 7, for example, when the inverter board P21A receives a thermo-off instruction from the outside of the board P21A, the coil power switch 23a in the board P21A is turned off, and the board P21A is interlocked with this. The power switch 22 (specifically, the relay switches 22b and 22c) is turned off. As a result, in the inverter board P21A that has received the thermo-off instruction, the output of the drive voltages SU to SW to the motor M21A corresponding to the board P21A is stopped, and the drive of the motor M21A is stopped. In addition, when the coil power switch 23a in the inverter board P21A is turned off, the output of the abnormality detection circuit 25 of the board P21A also becomes “about 0V” representing the off state. On the other hand, in the other inverter boards P21B and P21C that have not received the thermo-off instruction, the state of the switches 23a and 22 does not change. Accordingly, the other inverter boards P21B and P21C continue to output the drive voltages SU to SW to the motors M21B and M21C regardless of the inverter board P21A.

  When the inverter board P21A receives a thermo-on instruction from the outside, the coil power switch 23a on the board P21A is turned on, and the power switch 22 on the board P21A side is turned on. As a result, the inverter board P21A that has received the thermo-on instruction outputs the drive voltages SU to SW to the motor M21A, so that the motor M21A is driven.

(3-2-2) Example at Abnormality FIG. 8 is a timing chart showing an example of the operation of each switch and circuit on each of the substrates P1, P21A to P21C when an abnormality occurs in one of the three compressors. It is a chart.

  Of the three compressors, when an abnormality occurs in the compressor corresponding to the inverter board P21A, the abnormality detection switch S11 changes from on to off. The other abnormality detection switches S12 and S13 and the leakage current switch S14 remain on. At this moment, since the voltage value of the connection point sa drops from about 16V to about 0V, the output of the drive voltages SU to SW to the motors M21A to M21C is stopped on all the inverter boards P21A to P21C. Further, from the moment when the abnormality detection switch S11 changes from on to off, the relay coils S15a to S17a related to the state change switches S15 to S17 of the power control board P1 are replaced with a voltage of about 16V from the power line L11. Thus, a voltage according to the charge amount of the delay countermeasure capacitor C11 is applied, and the capacitor C11 discharges. When the voltage across the delay countermeasure capacitor C11 and all of the relay coils S15a to S17a becomes about 9 V or less, the relay switches S15b to S17b in all the state change switches S15 to S17 change from on to off. Due to the state change of the relay switches S15b to S17b, on all inverter boards P21A to P21C, the relay switches 22b and 22c of the power switch 22 are turned on and off, and the output of the abnormality detection circuit 25 is changed from “about 5V” to “about 0V”. "The coil power switch 23a changes from on to off.

  By such an operation, as shown in FIG. 8, the delay countermeasure capacitor C <b> 11 is from the time when the abnormality detection switch S <b> 11 changes from on to off until the state change switches S <b> 15 to S <b> 17 change from on to off. Due to the delay time.

(4) Features (4-1)
According to the power control board P1 according to the present embodiment, when at least one abnormality detection switch S11 to S13 changes from the on state to the off state, the state changes in the abnormality detection switches S11 to S13 whose state has changed. The state change switches S15 to S17 all change from on to off, and all the power switches 22 of the inverter boards P21A to P21C change from the on state to the off state. As a result, even when at least one abnormality detection switch S11 to S13 detects an abnormality of the compressor, power supply to all the motors M21A to M21C is cut off. Therefore, the power supply to the motor can be reliably cut off by an inexpensive and simple method.

(4-2)
The power control board P1 according to the present embodiment is provided with a delay countermeasure capacitor C11. According to the delay countermeasure capacitor C11, at least one of the abnormality detection switches S11 to S13 changes from the on state to the off state, and at the same time, all the state change switches S15 to S17 do not change from the on state to the off state. Instead, after at least one abnormality detection switch S11 to S13 changes from the on state to the off state, all the state change switches S15 to S17 change from the on state to the off state. As a result, the power control board P1 detects the voltage at the connection point sa on the inverter boards P21A to P21C before the power switches 22 on all the inverter boards P21A to P21C are turned off. Can be sent as. Therefore, the inverter units 21a of all the inverter boards P21A to P21C can stop the output of the drive voltages SU to SW to the motors M21A to M21C before the power switch 22 is turned off. Therefore, welding can be prevented from occurring in the transistors Q31a to Q33b of the inverter unit 21a and the power switch 22 (more specifically, the relay switches 22b and 22c of the power switch 22).

(4-3)
In addition, the power control board P1 according to the present embodiment employs a so-called weak electric circuit configuration in which a voltage of about 16V is applied to the abnormality detection switches S11 to S13 as a voltage lower than about 30V. Therefore, it is possible to use a low-power capacitor having a relatively high breakdown voltage as the delay countermeasure capacitor C11.

(4-4)
Further, according to the power control board P1 according to the present embodiment, even if a back electromotive force is generated in each of the relay coils S15a to S17a when at least one abnormality detection switch S11 to S13 is changed from an on state to an off state, Preventing diodes D11 and D12 prevent current backflow associated with the back electromotive force. Therefore, it is possible to prevent the elements mounted on the power control board P1 from being destroyed by the backflow of the current accompanying the back electromotive force generated in each of the relay coils S15a to S17a.

(4-5)
Further, according to the power control board P1 according to the present embodiment, the state change switches S15 to S17 are turned on / off not only by the abnormality detection switches S11 to S13 but also by the leakage current switch S14 that is turned on / off based on the leakage current. Turned off. As a result, for example, an abnormality has occurred in any of the motors M21A to M21C and leakage current is flowing. However, even if the abnormality detection switches S11 to S13 cannot detect the leakage current as abnormal, all of them are detected by the leakage current switch S14. The state change switches S15 to S17 are turned off. Therefore, the power supplied to the motors M21A to M21C can be cut off more reliably.

(4-6)
In particular, three inverter boards P21A to P21C are connected to the power control board P1 according to the present embodiment. The power switches 22 of these inverter boards P21A to P21C are connected to the commercial power supply 51 depending on the states that the state change switches S15 to S17 can take or the coil power switch 23a that is different from the state change switches S15 to S17. The power supply to the motors M21A to M21C is cut off. Here, as described above, the coil power switch 23a can turn off the power switch 22 based on, for example, a thermo-off instruction when there is no abnormality or leakage current in the compressor and it is normal. It is a switch that can. Thereby, inverter board | substrate P21A-P21C is a simple structure, and can interrupt | block the power supply supplied to motor M21A-M21C reliably in any of the case where there is no abnormality regarding an air conditioning apparatus.

(5) Modifications Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration is not limited to the above-described embodiment, and can be changed without departing from the gist of the invention.

(5-1) Modification A
In the above embodiment, the case where the number of compressors is three has been described. However, the number of compressors is not limited to this and may be any number.

  Moreover, in this embodiment, since the number of compressors is three, the case where abnormality detection switches S11 to S13, state change switches S15 to S17, and three inverter boards P21A to P21C are provided is described. did. However, the number of abnormality detection switches and inverter boards is not limited to three, but may be plural. The number of state change switches is not limited to three, and may be plural or one.

  Further, the number of the second interfaces 18a to 18c is not limited to three, and may be one or more.

(5-2) Modification B
In the above embodiment, a case has been described in which one delay countermeasure capacitor C11 of the power control board P1 is provided for the three state change switches S15 to S17. However, three delay countermeasure capacitors may be provided so as to correspond to the three state change switches S15 to S17, respectively. An example of the circuit configuration of the power control board P1 in this case is shown in FIG.

  In FIG. 9, delay countermeasure capacitors C111, C112, and C113 are connected in parallel to the relay coils S15a, S16a, and S17a. In addition to the delay countermeasure capacitors C111 to C113, in FIG. 9, leakage current switches S141, S142, S143, resistors R111, R112, R113, backflow prevention diodes D111, D112, D113, D121, D122, D123 are also included. Three relay coils are provided so as to correspond to the relay coils S15a, S16a, and S17a. The output of one leakage current detection circuit 14 is connected to the gates of the leakage current switches S141 to S143, and the emitters of the leakage current switches S141 to S143 are the same as the leakage current switch S14 of FIG. Collectively, it is connected to one end of the abnormality detection switch S13. The collectors of the leakage current switches S141 to S143 are connected to the GND via the resistors R111 to S113. The circuit configuration subsequent to the connection point sa of each of the leakage current switches S141 to S143 is the same as the circuit configuration subsequent to the connection point sa of the leakage current switch S14 of FIG.

  The circuit configuration as shown in FIG. 9 is suitable, for example, when it is desired to vary the delay time when the power switch 22 is disconnected for each of the inverter boards P21A to P21C. This is because the capacitance of each of the delay countermeasure capacitors C111 to C113 can be set to a different value for each of the inverter boards P21A to P21C.

  In the above embodiment, the case where the delay unit is configured by the capacitor C11 has been described. However, the delay unit only needs to change the power switch 22 of each inverter board P21A to P21C from the on state to the off state after at least one of the abnormality detection switches S11 to S13 changes from on to off. Other configurations may be used.

(5-3) Modification C
In the above embodiment, the case where the abnormality detection switches S11 to S13 detect abnormality of the compressor has been described. However, the abnormality detected by the abnormality detection switches S11 to S13 is not limited to the abnormality of the compressor. Other examples of the abnormality detected by the abnormality detection switches S11 to S13 include, for example, an abnormal rotation of the outdoor fan, a thermal abnormality of the entire indoor unit due to the ignition of the outdoor unit, and the like.

(5-4) Modification D
In the above embodiment, the case where the refrigeration apparatus is an air conditioner has been described as an example. However, the refrigeration apparatus can be, for example, a heat pump apparatus or the like, and may be other than an air conditioner.

(5-5) Modification E
In the said embodiment, as shown in FIG. 3, the case where the inverter part 21a and the voltage application control part 21b by the side of each inverter board | substrate P21A-P21C were comprised by one MPU21 for inverters was demonstrated. However, the inverter unit 21a and the voltage application control unit 21b do not have to be configured by one MPU, and may be configured by separate MPUs for each function.

(5-6) Modification F
In the above embodiment, as shown in FIG. 3, the case where the relay coil 22a of the power switch 22 is electrically connected between the coil power switch 23a and the connector 24 of the state change switches S15 to S17 has been described. However, the coil power switch 23a and the connectors 24 of the state change switches S15 to S17 are only required to be electrically connected in series to the relay coil 22a, and may not be electrically connected so as to sandwich the relay coil 22a. Good.

  For example, FIG. 10 shows a circuit configuration of inverter boards P21A ′ to P21C ′ in which the connectors 24 of the state change switches S15 to S17 are connected to the end sc side of the relay coil 22a, like the coil power switch 23a. Yes. 11, the coil power switch 23a has a circuit configuration of inverter boards P21A ″ to P21C ″ connected to the end sd side of the relay coil 22a, like the connector 24 of the state change switches S15 to S17. Show.

  Although not shown, the arrangement of the coil power switch 23a and the state change switches S15 to S17 may be opposite to that shown in FIG. That is, the coil power switch 23a may be connected to the end sd side of the relay coil 22a, and the state change switches S15 to S17 may be connected to the end sc side of the relay coil 22a.

(5-7) Modification G
In the above embodiment, the case where the abnormality detection circuit 25 is configured by the photocoupler 25a and the like has been described. However, the abnormality detection circuit 25 only needs to be able to detect the occurrence of an abnormality in the air conditioner based on the state change of the state change switches S15 to S17 electrically connected to the switch control circuit 23. The specific configuration is shown in FIG. It is not limited to.

(5-8) Modification H
In the above embodiment, the case where the power supplied to the switch control circuit 23 and the abnormality detection circuit 25 is about 15 V and about 5 V, respectively, has been described. However, the power supplied to the switch control circuit 23 and the abnormality detection circuit 25 is not limited to these values, and can be, for example, about 10 V, about 3 V, or the like.

101 Motor Drive System M21A, M21B, M21C Motor P1 Power Control Board S11, S12, S13 Abnormality Detection Switch S14 Leakage Current Switch 14 Leakage Current Detection Circuit C11 Delay Countermeasure Capacitor D11, D12 Backflow Prevention Diode S15, S16, S17 Change switches S15a, S16a, S17a Relay coils S15b, S16b, S17b Relay switches P21A, P21B, P21C Inverter board 21 MPU for inverter
21a Inverter unit 21b Voltage application control unit 22 Power switch 22a Relay coils 22b and 22c Relay switch 23 Switch control circuit 23a Coil power switch 24 Connector 25 for connecting the state change switch and the switch control circuit Anomaly detection circuit

Japanese Patent Laid-Open No. 11-83211

Claims (5)

A plurality of power switches (22) that turn on / off power supply to motors (M21A to M21C) that are drive sources of equipment included in the refrigeration apparatus, and an inverter (21a) that outputs a drive voltage to the motors are mounted. A plurality of connecting portions (11a to 11c) connected to the inverter substrate (P21A to P21C);
A plurality of abnormality detection switches (S11 to S13) that take an off state when there is an abnormality relating to the refrigeration apparatus, and take an on state when there is no abnormality relating to the refrigeration apparatus;
It is electrically connected to the power switch of each inverter board via each connection portion, and the power switch is turned on or off by turning on / off according to the on / off of the abnormality detection switch. A state change switch (S15 to S17) to be changed to
A leakage current switch (S14) capable of turning on / off the state change switch based on the value of leakage current in the motor or the device included in the refrigeration apparatus;
A control unit (21) for controlling the output operation of the drive voltage to the inverter;
With
When at least one of the plurality of abnormality detection switches is turned off from the on state, or when the leakage current switch is turned off from the on state when the value of the leakage current is higher than a reference value, The state change switch changes the power switch of all the inverter boards from an on state to an off state,
The controller controls the inverters on all of the plurality of inverter boards while the power switch is turned off after at least one of the plurality of abnormality detection switches and the leakage current switch is turned off. To stop the output operation of the drive voltage,
Power control board (P1) of the refrigeration apparatus. A delay that delays the timing when the state change switch changes from the on state to the off state so that the power switch changes from the on state to the off state after the abnormality detection switch changes from the on state to the off state. Part (C11),
Further comprising
The power control board (P1) of the refrigeration apparatus according to claim 1. A voltage lower than about 30 V is applied to the abnormality detection switch.
The power control board (P1) of the refrigeration apparatus according to claim 1 or 2. The state change switch (S15 to S17) includes a state change relay switch (S15b to S17b) and a state change relay coil (S15a to S17a) connected in series to the abnormality detection switch.
The state change relay coil is connected in parallel or in series, and when the abnormality detection switch changes from an on state to an off state, a current caused by a counter electromotive force generated in the state change relay coil flows backward. Backflow prevention unit (D11, D12) to prevent,
Further comprising
The power control board (P1) of the refrigeration apparatus according to any one of claims 1 to 3. The power switch (22) includes a power relay coil (22a) electrically connected in series with the state change switch, and a power relay switch (22b, 22c) disposed between a commercial power source and the motor. )
Each inverter board has
A coil power switch (23a) connected in series with the power relay coil and turning on / off the power supply to the power relay coil is further mounted;
The power relay switch is turned off based on the voltage across the power relay coil when the state change switch is off or the coil power switch is off.
The power control board (P1) of the refrigeration apparatus according to any one of claims 1 to 4.

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