Refrigeration cycle device and fan control device

Abstract

To provide a refrigeration cycle device and a fan control device capable of appropriately operating a fan during leakage of a refrigerant even when a control section for determining presence / absence of leakage of the refrigerant is abnormal.SOLUTION: A refrigeration cycle device according to one embodiment includes a fan, a fan motor, a refrigerant detection section, a control section, a drive section, and a leakage detection section. The fan motor rotates the fan. The refrigerant detection section outputs a detection signal related to presence / absence of leakage of a refrigerant. The control section includes: an input part to which the detection signal is input; and a signal generation part that generates a control signal for controlling the fan motor. The drive section drives the fan motor on the basis of the control signal. The leakage detection section detects leakage of the refrigerant on the basis of the detection signal, and outputs a forced drive signal to the drive section. When the forced drive signal is input, the drive section drives the fan motor regardless of the control signal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a refrigeration cycle device and a fan control device. [Background technology]

[0002] In recent years, there has been a demand for air conditioners to switch to refrigerants with low global warming potential (GWP). However, since refrigerants with low GWP are often flammable or slightly flammable, when a refrigerant leaks due to, for example, damage to a refrigerant circuit or poor installation, it is necessary to prevent the refrigerant concentration from becoming locally high. For example, Patent Document 1 discloses a refrigeration cycle device that includes a refrigerant detection means for detecting the concentration of the leaked refrigerant and a control unit for determining the presence or absence of a refrigerant leak based on a detection signal from the refrigerant detection means, and that operates an indoor fan to diffuse the leaked refrigerant into the indoor space when the control unit determines that a refrigerant leak has occurred. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-197006 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the refrigeration cycle device described in Patent Document 1, if the control unit that determines whether or not there is a refrigerant leak has an abnormality such as a malfunction or failure due to a breakdown, the indoor fan cannot be operated properly when there is a refrigerant leak.

[0005] In view of the above circumstances, an object of the present invention is to provide a refrigeration cycle device and a fan control device that can operate a fan properly when a refrigerant leaks, even if there is an abnormality in the control unit that determines whether or not there is a refrigerant leak. [Means for solving the problem]

[0006] A refrigeration cycle apparatus according to one aspect of the present invention includes a fan, a fan motor, a refrigerant detection unit, a control unit, a drive unit, and a leakage detection unit. The fan motor rotates the fan. The refrigerant detection unit outputs a detection signal indicating the presence or absence of a refrigerant leak. The control unit has an input unit to which the detection signal is input, and a signal generation unit that generates a control signal for controlling the fan motor. The drive unit drives the fan motor based on the control signal. The leakage detection unit detects a refrigerant leakage based on the detection signal and outputs a forced drive signal to the drive unit. When the forced drive signal is input, the drive unit drives the fan motor regardless of the control signal.

[0007] The refrigeration cycle apparatus may further include a signal transmission unit having a first transmission path for transmitting a drive signal based on the control signal and a second transmission path for transmitting the forced drive signal by merging with the first transmission path. The signal transmission unit may input the forced drive signal to the drive unit when both the drive signal and the forced drive signal are output.

[0008] The drive signal may be an active-low PWM signal, and the forced drive signal may be a low-level signal.

[0009] The refrigerant detection unit may output a signal that changes depending on the concentration of the detected refrigerant to the leak detection unit and the control unit as the detection signal, and when the control unit determines that the concentration of the refrigerant is equal to or higher than a predetermined threshold, it may output a PWM signal of a predetermined duty ratio as the control signal.

[0010] The signal transmission unit may further include a signal transmission element that inputs the drive signal or the forced drive signal to the drive unit while electrically insulating a junction between the first transmission path and the second transmission path and the drive unit.

[0011] The control unit may further include a determination unit that determines whether the signal generating unit is normal. The leakage detection unit may not output the forced drive signal when the determination unit determines that the signal generating unit is normal.

[0012] The leakage detection unit may have a signal line that transmits the detection signal to the drive unit, a first branch line branching off from the signal line, a second branch line branching off from the signal line between the refrigerant detection unit and the first branch line and inputting the detection signal to the input unit, and a resistor unit provided on the signal line between the first branch line and the second branch line. The control unit may further have a switch unit that connects the first branch line to ground when the determination unit determines that the signal generation unit is normal.

[0013] A fan control device according to one aspect of the present invention is a fan control device that controls a fan motor that rotates a fan, and includes a refrigerant detection unit, a control unit, a drive unit, and a leakage detection unit. The refrigerant detection unit outputs a detection signal indicating the presence or absence of a refrigerant leak. The control unit has an input unit to which the detection signal is input, and a signal generation unit that generates a control signal for controlling the fan motor. The drive unit drives the fan motor based on the control signal. The leakage detection unit detects a refrigerant leakage based on the detection signal and outputs a forced drive signal to the drive unit. When the forced drive signal is input, the drive unit drives the fan motor regardless of the control signal. Effect of the Invention

[0014] According to the present invention, even if there is an abnormality in the control unit that determines whether or not there is a refrigerant leak, the fan can be operated properly when there is a refrigerant leak. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a configuration example of a refrigeration cycle device equipped with a fan control device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a circuit diagram showing an example of the fan control device. [Diagram 3] 2 is a block diagram showing a configuration of a control unit in the fan control device. FIG. [Figure 4] FIG. 2 is a waveform diagram showing an example of a detection signal (A) when no refrigerant is leaking, and a voltage signal (B) obtained by smoothing the detection signal. [Diagram 5] 4 is a waveform diagram showing an example of a detection signal (A) when a refrigerant leaks and a voltage signal (B) obtained by smoothing the detection signal. FIG. [Figure 6] 5 is a flowchart showing an example of a process executed in the fan control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] [Refrigeration cycle equipment] 1 is a schematic diagram showing a configuration example of a refrigeration cycle apparatus 100 equipped with a fan control device 10 according to this embodiment. In this embodiment, an example of application of the refrigeration cycle apparatus 100 to an air conditioner will be described.

[0018] As shown in FIG. 1, the refrigeration cycle apparatus 100 has an indoor unit 2 and an outdoor unit 3. The indoor unit 2 is installed in an indoor space within a building and used. The indoor unit 2 has an indoor heat exchanger 20 and an indoor blower . The outdoor unit 3 is installed outdoors of the building in which the indoor unit 2 is installed, and is connected to the indoor unit 2 via refrigerant piping through which a refrigerant flows. The outdoor unit 3 has a compressor 30, an outdoor heat exchanger 31, a pressure reducer (expansion valve) 32, a flow switch (four-way valve) 33, and an outdoor fan 34.

[0019] For example, during heating operation, as shown by the solid arrow, the high-temperature, high-pressure gas refrigerant discharged from the compressor 30 flows into the indoor heat exchanger 20 functioning as a condenser through the flow path switching device 33. The high-temperature, high-pressure gas refrigerant that flows into the indoor heat exchanger 20 exchanges heat with the indoor air and condenses (liquefies), and the air that has been warmed by the heat exchange with the refrigerant is blown into the room by the indoor fan 21 to heat the room. The high-temperature, high-pressure liquid refrigerant is then reduced in pressure by passing through the pressure reducing device 32 to become a low-temperature, low-pressure two-phase gas-liquid refrigerant, and flows into the outdoor heat exchanger 31 functioning as an evaporator. The low-temperature, low-pressure two-phase gas-liquid refrigerant that flows into the outdoor heat exchanger 31 exchanges heat with the outdoor air blown by the outdoor fan 34 and evaporates (vaporizes). The low-temperature, low-pressure gas refrigerant is then sucked into the compressor 30 through the flow path switching device 33.

[0020] During cooling operation, as shown by the dashed arrow, the high-temperature, high-pressure gas refrigerant discharged from the compressor 30 flows into the outdoor heat exchanger 31 functioning as a condenser through the flow path switching device 33. The high-temperature, high-pressure gas refrigerant that flows into the outdoor heat exchanger 31 exchanges heat with the outside air blown by the outdoor fan 34 and condenses (liquefies). The high-temperature, high-pressure liquid refrigerant is then reduced in pressure by passing through the pressure reducing device 32 to become a low-temperature, low-pressure two-phase gas-liquid refrigerant, and flows into the indoor heat exchanger 20 functioning as an evaporator. The low-temperature, low-pressure two-phase gas-liquid refrigerant that flows into the indoor heat exchanger 20 exchanges heat with the indoor air and evaporates (vaporizes), and the air cooled by the heat exchange with the refrigerant is blown into the room by the indoor fan 21 to cool the room. The low-temperature, low-pressure gas refrigerant is then sucked into the compressor 30 through the flow path switching device 33.

[0021] The indoor fan 21 is, for example, a sirocco fan, and is driven by a fan motor 22. The fan motor 22 is, for example, a permanent magnet synchronous motor (PM synchronous motor) having a rotor to which a permanent magnet is attached and a stator in which a winding is arranged. The fan motor 22 is provided with three-phase windings, namely, U-phase, V-phase, and W-phase, and an AC voltage output from the fan control device 10 is applied to the windings of each phase.

[0022] On the other hand, the outdoor fan 34 is, for example, a propeller fan that generates an airflow in response to the rotation of an impeller, and is driven by a fan motor 35. The fan motor 35 is also, for example, a permanent magnet synchronous motor, and is controlled by an outdoor unit control device 36 that controls the outdoor unit 3. Note that a description of the outdoor unit control device 36 will be omitted.

[0023] The fan control device 10 is configured, for example, as an indoor unit control device provided in the housing of the indoor unit 2 as a part of the indoor unit 2, or as a part thereof. The fan control device 10 normally executes control to rotate the indoor fan 21 at a rotation speed stored in a memory 126 described later, based on a set air volume set by a user via a remote control (not shown) or the like. In addition, when a refrigerant leak is detected in the indoor unit 2, the fan control device 10 executes control to rotate the indoor fan 21 to diffuse the refrigerant leaked into the indoor unit 2 into the indoor space in which the indoor unit 2 is installed. Details of the fan control device 10 will be described below.

[0024] [Fan control device] As shown in Fig. 1, fan control device 10 has a refrigerant detection unit 11, a control unit 12, a leakage detection unit 13, a signal transmission unit 14, and a drive unit 15. Fig. 2 is a circuit diagram showing an example of fan control device 10, and Fig. 3 is a block diagram showing the configuration of control unit 12.

[0025] (Refrigerant detection unit) The refrigerant detection unit 11 is installed in the indoor unit 2, and outputs a detection signal regarding the presence or absence of a refrigerant leak. The detection signal is input to the control unit 12 and the leakage detection unit 13.

[0026] In this embodiment, a refrigerant sensor that can detect not only the presence or absence of a refrigerant leak but also the concentration of the leaked refrigerant is used as refrigerant detection unit 11. As this type of refrigerant sensor, for example, a sensor that has sensitivity to a specific component that constitutes the refrigerant and outputs a detection signal with a larger pulse width as the concentration of the specific component increases is used.

[0027] (Control unit) The control unit 12 has an input unit 121, a communication unit 122, a signal generation unit 123, a determination unit 124, a switch unit 125, and a memory 126. The memory 126 is a storage element that stores a program for executing the operation of each unit of the control unit 12, which will be described later. Note that the input unit 121, the communication unit 122, the signal generation unit 123, and the memory 126 are omitted in FIG.

[0028] A detection signal from the refrigerant detection unit 11 is input to the input unit 121. The communication unit 122 is a communication module capable of communicating with the outdoor unit control unit 36. The communication unit 122 transmits, for example, the required operating capacity of the indoor unit 2 to the outdoor unit control unit 36 ​​and receives a signal related to the operating state of the outdoor unit 3 from the outdoor unit control unit 36.

[0029] The signal generating unit 123 determines whether or not there is a refrigerant leak based on the detection signal input to the input unit 121, or determines whether or not the concentration of the leaked refrigerant is equal to or higher than a predetermined threshold based on the detection signal. The predetermined threshold is a concentration lower than the lower flammable limit concentration of the refrigerant, and is a concentration at which it is recognized that the refrigerant has leaked. Note that the above-mentioned process of determining whether or not there is a refrigerant leak or whether or not the refrigerant concentration is equal to or higher than the threshold may be executed by the input unit 121 instead of the signal generating unit 123.

[0030] Furthermore, the signal generating unit 123 generates a control signal for controlling the fan motor 22 that rotates the indoor fan 21. In this embodiment, the signal generating unit 123 includes a PWM modulator that generates a PWM (Pulse Width Modulation) signal for rotating the indoor fan 21 at a predetermined rotation speed as the control signal. The control signal generated by the signal generating unit 123 is a pulse signal, and is output to the driving unit 15 via the signal transmitting unit 14.

[0031] When no refrigerant leakage is detected, the signal generating unit 123 generates a control signal based on the rotation speed based on the set air volume set by the user, and when a refrigerant leakage is detected, it generates a control signal to rotate the indoor fan 21 at a predetermined rotation speed required to mix the air in the indoor space in which the indoor unit 2 is installed and diffuse the leaked refrigerant.

[0032] The determination unit 124 determines whether the signal generating unit 123 is normal or not. The signal generating unit 123 being normal means a state in which the signal generating unit 123 executes each of the above-mentioned processes in accordance with the program stored in the memory 126. Therefore, when a functional stop or malfunction occurs due to a failure, the signal generating unit 123 is determined to be abnormal.

[0033] To determine whether the signal generating unit 123 is normal or not, a self-monitoring function (WDT: watchdog timer) generally installed in a microcomputer can be used. In this embodiment, the control unit 12 outputs a signal (Hi signal) indicating the state when a program executing the function of the signal generating unit 123 is proceeding normally, and outputs a Lo signal when the signal generating unit 123 is not operating normally. The determination unit 124 determines whether the signal generating unit 123 is normal or not by monitoring the port that outputs the Hi or Lo signal.

[0034] When the determination unit 124 determines that the signal generation unit 123 is normal, it executes an operation of closing (turning on) the switch unit 125. As shown in Fig. 2, the switch unit 125 is a switching element capable of connecting the signal line L0, which transmits the detection signal in the leakage detection unit 13, to a ground potential. The details of the switch unit 125 will be described later.

[0035] (Leak detection section) Leakage detection unit 13 detects a refrigerant leakage based on the detection signal from refrigerant detection unit 11, and outputs a forced drive signal to drive unit 15. Leakage detection unit 13 has a smoothing circuit 131 and a comparator 132, as shown in FIG.

[0036] The smoothing circuit 131 is a circuit that smoothes the detection signal input to the signal line L0, and outputs an average voltage signal of the detection signal. The smoothing circuit 131 includes, for example, a capacitor (smoothing capacitor) of a predetermined capacity connected between the signal line L0 and a ground potential. The detection signal output from the refrigerant detection unit 11 is a pulse signal having a pulse width according to the concentration of the refrigerant, as described above. The smoothing circuit 131 converts the pulse width into a voltage, and outputs the average voltage as a voltage signal.

[0037] Fig. 4A shows an example of a detection signal when there is no refrigerant leakage, and Fig. 4B shows an example of a voltage signal corresponding to that detection signal. The refrigerant detection unit 11 outputs a pulse signal with a predetermined pulse width W0 even when there is no refrigerant leakage. As a result, if a malfunction or the like occurs in the refrigerant detection unit 11, for example, an abnormality in the refrigerant detection unit 11 can be detected based on the presence or absence of a pulse waveform. The pulse width W0 is set so that the average voltage V0 is a value smaller than a preset threshold value Th. The threshold value Th is set to a voltage value corresponding to the refrigerant concentration at which it is recognized that refrigerant has leaked in the indoor unit 2.

[0038] Meanwhile, Fig. 5A shows an example of a detection signal when refrigerant leaks, and Fig. 5B shows an example of a voltage signal corresponding to the detection signal. When refrigerant of a predetermined concentration or more leaks, refrigerant detection unit 11 outputs a pulse signal with a pulse width W1 according to the concentration of the refrigerant, and smoothing circuit 131 outputs a voltage signal with an average voltage V1 corresponding to the pulse width W1.

[0039] The comparator 132 is a comparator that compares the output voltage of the smoothing circuit 131 with a predetermined reference voltage Vref. The output voltage of the smoothing circuit 131 is input to a negative input terminal of the comparator 132, and the reference voltage Vref is input to a positive input terminal of the comparator 132. The reference voltage Vref is a voltage equivalent to a threshold value Th.

[0040] When the output voltage of the smoothing circuit 131 is lower than the reference voltage Vref, such as when there is no refrigerant leakage, the comparator 132 outputs a high-level output signal to the signal transmission unit 14. On the other hand, when the output voltage of the smoothing circuit 131 is equal to or higher than the reference voltage Vref, such as when there is a refrigerant leakage, the comparator 132 outputs a low-level (for example, ground potential) output signal as a forced drive signal to the signal transmission unit 14.

[0041] The leak detection unit 13 further has a first branch line L1 and a second branch line L2.

[0042] The first branch line L1 branches off from the signal line L0 between the refrigerant detection unit 11 and the smoothing circuit 131, and is connected to the ground potential via the switch unit 125 of the control unit 12. As described above, the switch unit 125 is turned on when the determination unit 124 determines that the signal generation unit 123 is normal, and is turned off when the determination unit 124 determines that the signal generation unit 123 is abnormal.

[0043] Therefore, when the signal generating unit 123 is normal, the first branch line L1 is connected to the ground potential, and the detection signal transmitted through the signal line L0 flows to the ground potential without being input to the smoothing circuit 131. As a result, the output voltage of the smoothing circuit 131 becomes 0V regardless of the presence or absence of a refrigerant leak, so that no forced drive signal is output from the leakage detection unit 13 even when a refrigerant leaks. On the other hand, when the signal generating unit 123 is not normal, i.e., is abnormal, the first branch line L1 is disconnected from the ground potential, and the detection signal transmitted through the signal line L0 is input to the smoothing circuit 131. As a result, a forced drive signal is output from the leakage detection unit 13 when a refrigerant leaks.

[0044] The second branch line L2 branches off from the signal line L0 between the refrigerant detection unit 11 and the first branch line L1, and inputs the detection signal to the input unit 121 of the control unit 12. A first resistor R1 for inputting the detection signal to the input unit 121 is provided between a branch point B1 of the first branch line L1 from the signal line L0 and a branch point B2 of the second branch line L2 from the signal line L0. As a result, even when the switch unit 125 is turned on and the signal line L0 is connected to ground potential, the detection signal branched off at branch point B2 is input to the input unit 121 without flowing to ground potential. The resistance value of the first resistor R1 is not particularly limited, and may be any resistance value that allows the detection signal to be stably input to both the input unit 121 and the smoothing circuit 131.

[0045] [Signal transmission section] The signal transmission unit 14 has a first transmission path T1 and a second transmission path T2. The first transmission path T1 transmits a drive signal based on a control signal output from the control unit 12 to the drive unit 15. On the other hand, the second transmission path T2 merges with the first transmission path T1 and transmits a forced drive signal output from the leakage detection unit 13 to the drive unit 15. The drive signal and the forced drive signal will be described in detail later.

[0046] The signal transmission unit 14 further includes a signal transmission element 141. The signal transmission element 141 inputs a drive signal or a forced drive signal to the drive unit 15 while electrically insulating the drive unit 15 from a junction J of the first transmission path T1 and the second transmission path T2. This electrically insulates the circuit on the signal transmission unit 14 side from the circuit on the drive unit 15 side, which operates at a higher voltage than the signal transmission unit 14 side, so that the circuit on the signal transmission unit 14 side can be protected from the high voltage on the drive unit 15 side.

[0047] The signal transmission element 141 may be, for example, a photocoupler having a light emitting element P1 provided on the input side and a light receiving element P2 provided on the output side.

[0048] The light-emitting element P1 is a light-emitting diode. The anode of the light-emitting element P1 is connected to a first power source E1, and the cathode of the light-emitting element P2 is connected to a junction J of the first transmission path T1 and the second transmission path T2. The voltage of the first power source E1 is, for example, 5V. A second resistor R2 is connected in parallel with the light-emitting element P1 between the first power source E1 and the junction J. The second resistor R2 is a shunt resistor for preventing malfunction of the photocoupler due to minute current.

[0049] The light receiving element P2 is, for example, a phototransistor, and is turned on when it receives light emitted from the light emitting element P1. The collector of the light receiving element P2 is connected to a second power source E2, and the emitter of the light receiving element P2 is connected to the driving unit 15. The voltage of the second power source E2 is, for example, 15 V. A diode D is connected between the collector and emitter of the light receiving element P2, with the forward direction being from the emitter side to the collector side. The diode D is a backflow prevention diode for preventing return current from the driving unit 15 to the emitter.

[0050] The first transmission path T1 has a switching element 142 that is turned on and off depending on the signal level of the control signal. The switching element 142 is, for example, an N-type bipolar transistor that is turned on when the signal level of the control signal is high. One end (collector) of the switching element 142 is connected to the junction J with the second transmission path T2, and the other end (emitter) is connected to the ground potential.

[0051] The drive signal transmitted through the first transmission path T1 is generated by the on / off operation of the switching element 142. As described above, since the control signal generated in the control unit 12 (signal generating unit 123) is a pulse signal, the control signal is input to the switching element 142, whereby the junction J is connected to the ground potential in a time pattern corresponding to the pulse width / period (duty ratio) of the control signal. In addition, the signal level of the second transmission path T2, to which the forced drive signal is not output from the leakage detection unit 13, is maintained in a high state by the output of the comparator 132. As a result, during a period (on period) in which the switching element 142 is in an on operation, both the first transmission path T1 and the second transmission path T2 are connected to the ground potential, and the light-emitting element P1 is made conductive (light-emitting). On the other hand, during a period (off period) in which the switching element 142 is in an off operation, both the signal levels of the first transmission path T1 and the second transmission path T2 are at a high level, so that the light-emitting element P1 is prevented from being made conductive. In this way, the drive signal is generated as an active-low PWM signal having the same duty ratio as the PWM signal forming the control signal.

[0052] In contrast, the forced drive signal transmitted through the second transmission path T2 is a low-level signal output from the comparator 132 when the signal generating unit 123 is not operating normally as described above and there is a refrigerant leak (when the refrigerant detection unit 11 detects a refrigerant with a predetermined concentration or higher). When the signal level of the second transmission path T2 is low, the light-emitting element P1 is energized (emits light). Since the forced drive signal is a constant low-level signal, the light-emitting element P1 continuously emits light.

[0053] [Drive unit] The driving unit 15 is an inverter circuit that receives power from the second power source E2 and generates AC power that is output to the fan motor 22. The driving unit 15 is supplied with power from the second power source E2 during the ON period of the light receiving element P2. Since the voltage of the second power source E2 is higher than the voltage of the first power source E1, the driving signal and the forced driving signal are amplified to a level corresponding to the voltage ratio between them and input to the driving unit 15.

[0054] As a result, when a drive signal is input via the first transmission path T1, the drive unit 15 drives the fan motor 22 at a rotation speed corresponding to the PWM signal with a predetermined duty ratio generated as the drive signal. On the other hand, when a forced drive signal is input via the second transmission path T2, the drive unit 15 drives the fan motor 22 at the maximum rotation speed under control that corresponds to continuous energization (duty ratio 1).

[0055] [Operation of refrigeration cycle equipment] Next, a description will be given of the operation of the refrigeration cycle apparatus 100 configured as above.

[0056] When the operation (cooling operation or heating operation) of the refrigeration cycle apparatus 100 is started, the control unit 12 of the fan control device 10 monitors the presence or absence of refrigerant leakage based on the detection signal of the refrigerant detection unit 11. That is, the control unit 12 determines the presence or absence of refrigerant leakage at a predetermined control period in the signal generation unit 123 based on the detection signal input to the input unit 121. In this embodiment, based on the detection signal, it is determined whether or not a refrigerant with a concentration equal to or higher than a predetermined threshold has been detected (ST101).

[0057] When no refrigerant leakage is detected (No in ST101), the control unit 12 rotates the indoor fan 21 at a rotation speed based on the set air volume set by the user (ST103).

[0058] In this case, the signal generating unit 123 of the control unit 12 generates a control signal (PWM signal) for rotating the indoor fan 21 at the above rotation speed. The signal transmitting unit 14 transmits the drive signal generated by opening and closing the switching element 142 based on the control signal to the driving unit 15 via the first transmission path T1 and the signal transmitting element 141.

[0059] On the other hand, when refrigerant has leaked into the indoor unit 2 due to deterioration or damage to the refrigerant piping of the indoor unit 2, and it is detected based on the detection signal that the concentration of the leaked refrigerant is above a predetermined threshold value (Yes in ST101), the control unit 12 determines whether the function of the signal generation unit 123 is normal or not using the judgment unit 124 (ST102).

[0060] When it is determined that the signal generating unit 123 is normal (Yes in ST102), the control unit 12 rotates the indoor fan 21 at a control rotation speed that is preset as the rotation speed required to make the concentration of the leaked refrigerant less than the threshold value (ST103). This makes it possible to diffuse the refrigerant that has leaked into the indoor unit 3 into the indoor space. The control rotation speed may be a fixed value, or may be a variable value that differs depending on the concentration of the detected refrigerant.

[0061] In this case, the signal generating unit 123 of the control unit 12 generates a control signal (PWM signal) with a predetermined duty ratio for rotating the indoor fan 21 at the above-mentioned control rotation speed. The signal transmitting unit 14 transmits a drive signal generated by opening and closing the switching element 142 based on the control signal to the driving unit 15 via the first transmission path T1 and the signal transmitting element 141.

[0062] Furthermore, when the signal generating unit 123 is normal, the switch unit 125 is on, and the signal line L0 of the leakage detection unit 13 is connected to the ground potential. Therefore, even if the refrigerant concentration is equal to or higher than a predetermined threshold, the output voltage of the smoothing circuit 131 is 0 V, which is lower than the reference voltage Vref, and therefore the leakage detection unit 13 does not output a forced drive signal.

[0063] On the other hand, when it is determined that the signal generating unit 123 is not normal (No in ST102), the determining unit 124 switches the switch unit 125 to the OFF state (ST104). As a result, a detection signal having a pulse width according to the refrigerant concentration is input to the smoothing circuit 131, and an average voltage V1 equal to or greater than the threshold value Th is output from the smoothing circuit 131, as shown in Fig. 5B, for example. This causes a forced drive signal to be output from the leakage detecting unit 13 via the signal transmitting unit 14 to the driving unit 15 of the fan motor 22, and the indoor fan 21 is rotated at the maximum rotation speed under control, which corresponds to continuous energization (duty ratio 1) (ST105).

[0064] When the signal generating unit 123 is not normal, the on / off operation of the switching element 142 also becomes unstable. For example, when the signal generating unit 123 stops functioning, the control signal becomes low level, so that the switching element 142 maintains the off state. In this case, the signal level of the second transmission path T2 is low, so that stable continuous current supply to the light-emitting element P1 is ensured, and the fan motor 22 can be driven at the maximum rotation speed. On the other hand, even if the signal generating unit 123 malfunctions and the control signal becomes an abnormal signal form, causing the on / off operation of the switching element 142 to exhibit an abnormality, the signal level of the second transmission path T2 is not affected, so that continuous current is ensured to the light-emitting element P1 even in this case. Therefore, when the signal generating section 123 is not normal, the signal transmitting section 14 inputs the forced drive signal to the driving section 15 if both the drive signal and the forced drive signal are being output.

[0065] As described above, according to this embodiment, when a forced drive signal is input, the drive unit 15 drives the fan motor 22 (indoor fan 21) without relying on a control signal from the control unit 12. Therefore, even if there is an abnormality in the control unit 12 (particularly the signal generating unit 123 in this embodiment), which determines whether or not there is a refrigerant leak, the indoor fan 21 can be operated properly when there is a refrigerant leak.

[0066] In addition, since the device is equipped with a signal transmission unit 14 having a first transmission path T1 for transmitting a drive signal and a second transmission path T2 for transmitting a forced drive signal, the above-mentioned effects of this embodiment can be obtained, for example, by incorporating the refrigerant detection unit 11 and the leakage detection unit 13 into the control device of an existing indoor unit 2.

[0067] Furthermore, when both the drive signal and the forced drive signal are output, the signal transmission unit 14 inputs the forced drive signal to the drive unit, so that even when the signal generation unit 123 is not normal, the indoor fan 21 can be forcibly driven to diffuse the refrigerant into the indoor space in which the indoor unit 2 is installed. Since the forced drive signal is a low-level signal transmitted through the second transmission path T2, it is possible to rotate the indoor fan 21 at the maximum rotation speed under control equivalent to continuous energization (duty ratio 1) with a simple configuration.

[0068] On the other hand, when the control unit 12 determines that the refrigerant concentration is equal to or higher than a predetermined threshold, it outputs a PWM signal with a predetermined duty ratio as a control signal. Therefore, even if the leakage detection unit 13 does not operate normally due to a malfunction or the like, the refrigerant can be diffused by rotating the indoor fan 21 in response to a control signal from the control unit 12 in the event of a refrigerant leak.

[0069] Moreover, since the signal transmission unit 14 includes the signal transmission element 141 that inputs a drive signal or a forced drive signal to the driver 15 while electrically insulating the junction J of the first transmission path T1 and the second transmission path T2 from the driver 15, the input side (first transmission path T1 and second transmission path T2) of the signal transmission element 141 can be protected from the high voltage of the output side (drive unit 15). Moreover, two different signals (drive signal and forced drive signal) can be input to the driver using the common signal transmission element 141.

[0070] Furthermore, according to this embodiment, the leakage detection unit 13 is configured not to output a forced drive signal when the judgment unit 124 judges that the signal generation unit 123 is normal. Therefore, when the control unit 12 is normal, it is possible to control the rotation speed of the indoor fan 21 using a drive signal based on a control signal from the control unit 12. This makes it possible to perform flexible control, such as reducing the fan rotation speed in response to a detected decrease in refrigerant concentration.

[0071] Furthermore, the signal line L0 of the leakage detection unit 13 is provided with a first branch line L1 that can be connected to ground potential across the first resistor R1, and a second branch line L2 that inputs the detection signal to the input unit 121. This ensures stable input of the detection signal to the control unit 12, making it possible to control the drive of the indoor fan 21 mainly by the control unit 12 when a refrigerant leak occurs, and also makes it possible to connect the signal line L0 to ground potential when the signal generation unit 123 is normal, thereby preventing a forced drive signal from being output.

[0072] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made thereto.

[0073] For example, in the above embodiment, the indoor fan 21 is the object to be controlled by the fan control device 10, but the present invention is not limited to this, and the outdoor fan 34 may be the object to be controlled. In this way, when refrigerant leaks from the outdoor unit 3, the outdoor fan 34 can be driven to diffuse the refrigerant into the outdoor space.

[0074] In the above embodiment, an air conditioner has been used as an example of the refrigeration cycle device 100, but the present invention is not limited to this, and can also be applied to a hot water supply system or a floor heating system that uses a water-refrigerant heat exchanger as a condenser. [Explanation of symbols]

[0075] 2…Indoor unit 3…Outdoor unit 10...Fan control device 11...Refrigerant detector 12...Control section 13...Leak detection section 14...Signal transmission section 15...Drive unit 21…Indoor fan 22...Fan motor 100...Refrigeration cycle device 121...Input section 122…Communications Department 123...signal generating unit 124...Judgment section 125…Switch section 131...Smoothing circuit 132…Comparator 141...Signal transmission element 142...Switching element L0: Signal line L1: First branch line L2: Second branch line R1…First resistor section (resistor section) T1…First transmission path T2: Second transmission path Vref: Reference voltage

Claims

1. With fans, A fan motor that rotates the fan; a refrigerant detection unit that outputs a detection signal indicating whether or not a refrigerant leaks; a control unit including an input unit to which the detection signal is input and a signal generating unit to generate a control signal for controlling the fan motor; a drive unit that drives the fan motor based on the control signal; a leakage detection unit that detects a leakage of the refrigerant based on the detection signal and outputs a forced drive signal to the drive unit; Equipped with When the forced drive signal is input, the drive unit drives the fan motor without depending on the control signal. Refrigeration cycle equipment.

2. The refrigeration cycle apparatus according to claim 1, a signal transmission unit including a first transmission path for transmitting a drive signal based on the control signal and a second transmission path for transmitting the forced drive signal by merging with the first transmission path, The signal transmission unit inputs the forced drive signal to the drive unit when both the drive signal and the forced drive signal are output. Refrigeration cycle equipment.

3. The refrigeration cycle apparatus according to claim 2, the drive signal is an active-low PWM signal, The forced drive signal is a low level signal. Refrigeration cycle equipment.

4. The refrigeration cycle apparatus according to claim 3, the refrigerant detection unit outputs a signal that changes depending on the concentration of the detected refrigerant as the detection signal to the leakage detection unit and the control unit; When the control unit determines that the concentration of the refrigerant is equal to or higher than a predetermined threshold, the control unit outputs a PWM signal having a predetermined duty ratio as the control signal. Refrigeration cycle equipment.

5. The refrigeration cycle apparatus according to claim 2, The signal transmission unit further includes a signal transmission element that inputs the drive signal or the forced drive signal to the drive unit while electrically insulating a junction between the first transmission path and the second transmission path and the drive unit. Refrigeration cycle equipment.

6. The refrigeration cycle apparatus according to claim 5, The signal transmission element is a photocoupler. Refrigeration cycle equipment.

7. The refrigeration cycle apparatus according to claim 4, The control unit further includes a determination unit that determines whether the signal generation unit is normal or not, The leakage detection unit does not output the forced drive signal when the determination unit determines that the signal generation unit is normal. Refrigeration cycle equipment.

8. The refrigeration cycle apparatus according to claim 7, The leakage detection unit is a signal line for transmitting the detection signal to the driving unit; a first branch line branching off from the signal line; a second branch line branching from the signal line between the refrigerant detection unit and the first branch line and inputting the detection signal to the input unit; a resistor portion provided in the signal line between the first branch line and the second branch line, The control unit further includes a switch unit that connects the first branch line to ground when the determination unit determines that the signal generation unit is normal. Refrigeration cycle equipment.

9. A fan control device that controls a fan motor that rotates a fan, a refrigerant detection unit that outputs a detection signal indicating whether or not a refrigerant leaks; a control unit including an input unit to which the detection signal is input and a signal generating unit to generate a control signal for controlling the fan motor; a drive unit that drives the fan motor based on the control signal; a leakage detection unit that detects a leakage of the refrigerant based on the detection signal and outputs a forced drive signal to the drive unit; Equipped with When the forced drive signal is input, the drive unit drives the fan motor without depending on the control signal. Fan control device.

Images