JPWO2019043857A1 - Air conditioner with inrush current limiting circuit - Google Patents

Abstract

It is connected in parallel to the NTC thermistor (4) and the NTC thermistor (4) for limiting the inrush current applied instantaneously when the AC power supply (1) is turned on, and can be opened and closed and opened and closed. In an air conditioner having an inrush current limiting circuit (2) having a relay contact (5) for short-circuiting the NTC thermistor, the relay contact (5) is closed when the relay contact (5) is opened. If the power consumption of the entire air conditioner is smaller than that, the relay contact (5) is controlled to open and the relay contact (5) is closed to open the relay contact (5). When the power consumption of the entire air conditioner is smaller than the above, the relay contact control unit (19) for controlling the relay contact (5) to the closed state is provided. Accordingly, a simpler circuit configuration than conventional it is possible to finely reduce the power consumption of the entire air conditioner.

Description

  The present invention relates to an air conditioner including an inrush current limiting circuit that limits an inrush current when an AC power supply is turned on, and in particular, an air including an inrush current limiting circuit having a resistor and a contact for limiting the inrush current. It is about a harmony machine.

  An inrush current limiting resistor that limits the inrush current applied instantaneously when the AC power is turned on, and a relay contact that is connected in parallel to the inrush current limiting resistor and can be opened and closed in an open state and a closed state In an air conditioner equipped with an inrush current limiting circuit having a relay, the power consumption at the inrush current limiting resistor is used to close the relay contact when the rotational speed of the fan motor exceeds a predetermined value. Since it is greater than the power consumption of the exciting coil, the relay contact is closed so that the current in the inrush current limiting circuit flows through the relay contact side, and if the fan motor speed is less than the specified value, inrush Since the power consumption at the current limiting resistor is smaller than the power consumption at the relay exciting coil for closing the relay contact, the relay contact must be opened. Structure current in the inrush current limiting circuit is to flow the inrush current limiting resistor side is proposed (e.g., see Patent Document 1).

  Also, in a hot water heater / heater, a power thermistor is used as an inrush current limiting resistor, and when the current flowing through the power thermistor is smaller than a threshold value when the hot water heater / operator is in a standby state, the relay excitation coil is excited. Without opening the relay contact so that the current in the inrush current limiting circuit flows through the inrush current limiting resistor, and the relay exciting coil is energized in the operating state where the current flowing through the power thermistor exceeds the threshold. There has been proposed a configuration in which the relay contact is closed and the current in the inrush current limiting circuit flows through the power thermistor (see, for example, Patent Document 2).

JP2010-104109A JP2012-217306

  In the configurations described in Patent Literature 1 and Patent Literature 2, based on a comparison between the power consumption of the inrush current limiting resistor and the power consumption of the relay exciting coil, the relay can reduce the power consumption of the inrush current limiting circuit. The current path in the inrush current limiting circuit is switched by controlling the open / closed state of the contact.

  However, simply reducing the power consumption of the inrush current limiting circuit is not sufficient to further reduce the power consumption of the entire air conditioner. In addition, it is not preferable to add a lot of new circuit parts to reduce the power consumption of the air conditioner and to greatly change the circuit configuration of the air conditioner, resulting in an increase in development and manufacturing costs.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an inrush current limiting circuit capable of reducing the power consumption of the entire air conditioner as compared with the prior art with a simpler circuit configuration. It is to obtain an air conditioner equipped with.

  The air conditioner equipped with the inrush current limiting circuit of the present invention is connected in parallel to the NTC thermistor that limits the inrush current applied instantaneously when the AC power is turned on, and the NTC thermistor can be opened and closed. In an air conditioner having an inrush current limiting circuit having a relay contact that short-circuits the NTC thermistor in the closed state, the relay contact is opened rather than the relay contact is closed. When the power consumption of the entire air conditioner is small, the entire air conditioner is controlled by controlling the relay contact in an open state and making the relay contact in a closed state rather than opening the relay contact. When the power consumption at the relay is small, a relay contact control unit that controls the relay contact to the closed state is provided. It is characterized by.

  The air conditioner provided with the inrush current limiting circuit according to the present invention is configured in this way, so that the power consumption of the entire air conditioner can be reduced more finely than before with a simpler circuit configuration.

The figure which shows the structure of the air conditioner provided with the inrush current limiting circuit in Embodiment 1. The figure explaining the circuit operation | movement of the air conditioner provided with the inrush current limiting circuit in Embodiment 1. The figure which shows the example of data of the data storage part in Embodiment 1 The figure explaining circuit operation | movement of the air conditioner provided with the inrush current limiting circuit in Embodiment 2. The figure explaining the circuit operation | movement of the air conditioner provided with the inrush current limiting circuit in Embodiment 3. The figure explaining the circuit operation | movement of the air conditioner provided with the inrush current limiting circuit in Embodiment 4.

Embodiment 1.
A structure and operation | movement are demonstrated based on FIG. 1 about the air conditioner provided with the inrush current limiting circuit in Embodiment 1. FIG. FIG. 1 is a diagram illustrating a configuration of an air conditioner including an inrush current limiting circuit. In addition, in FIG. 1, the articles | goods which comprise refrigeration cycles, such as a heat exchanger, a compressor, an expansion valve, and refrigerant | coolant piping with which the air conditioner is normally provided, are abbreviate | omitting illustration.

  The air conditioner includes an inrush current limiting circuit 2 having a function of limiting an inrush current that is instantaneously applied when the AC power supply 1 is turned on. The AC power supply 1 is turned on, for example, by inserting a power plug of the air conditioner into a power outlet or by turning on a power breaker installed in the house. This inrush current flows into the inrush current limiting circuit 2 from the AC power source 1 through the filter circuit 3. The filter circuit 3 is composed of a common mode choke coil, a capacitor and the like, and has a function of removing electromagnetic noise from the AC power source 1.

  The inrush current limiting circuit 2 includes an NTC thermistor 4 as an inrush current limiting resistor, and a relay 7 having a relay contact 5 and a relay exciting coil 6. Here, the NTC thermistor (Negative Temperature Coefficient Thermistor) is also referred to as a negative characteristic thermistor, and is a thermistor having a characteristic (negative characteristic) in which the resistance value decreases as the temperature rises.

  The NTC thermistor 4 has a function of limiting an inrush current that is instantaneously applied when the AC power supply 1 is turned on. The relay contact 5 is connected in parallel to the NTC thermistor 4 and can be opened and closed, and short-circuits the NTC thermistor 4 in the closed state. The relay contact 5 can be brought into a closed state by energizing the relay exciting coil 6 and is opened when the relay exciting coil 6 is not energized.

  Before the AC power supply 1 is turned on to the air conditioner, the microcomputer 19 is not activated and the relay exciting coil 6 is not energized, so the relay contact 5 is in an open state. When the AC power source 1 is turned on, an AC voltage is applied to the inrush current limiting circuit 2 in which the relay contact 5 is open, and the inrush current flows to the NTC thermistor 4 in the inrush current limiting circuit 2. The inrush current is limited by the resistance component of the thermistor 4.

  Thereafter, an AC voltage is converted into a DC voltage by a rectifier circuit formed by the diode bridge 8 and the smoothing capacitor 9. After being converted to the DC voltage, the power transformer 10, the power IC 11, the voltage generating diode 12 and the capacitor 13, the transformer secondary side rectifier diode 14, the relay exciting coil power capacitor 15, the microcomputer driving power IC 16 and the microcomputer driving power The power supply circuit 18 including the capacitor 17 generates a relay excitation coil power supply (V1) and a microcomputer drive power supply (V2). More specifically, the switching element incorporated in the power supply IC 11 is controlled by a PWM method or the like, thereby functioning as a DC / DC converter. The relay excitation coil power supply (V1) and the microcomputer drive power supply (V2). ) Is generated. Thus, the relay excitation coil power supply (V1) and the microcomputer drive power supply (V2) are obtained from the load side of the inrush current limiting circuit 2.

  After the AC power source 1 is turned on and the microcomputer driving power source (V2) is generated, the microcomputer 19 (an example of a relay contact control unit) is activated and enters a remote control standby state. During the remote control standby state, the microcomputer 19 outputs a signal for opening the relay contact 5 to the relay coil drive circuit 20 so that the relay excitation coil 6 is not energized, and the relay contact 5 remains open. Further, the microcomputer 19 performs start / stop of the fan motor 22 and rotation speed control via the fan motor control circuit 21. The fan motor 22 is a fan motor for an indoor fan mounted on, for example, an indoor unit of an air conditioner.

  When the user operates a remote controller (also referred to as a remote controller, not shown) to instruct to start or stop the operation of the air conditioner, the microcomputer 19 sends a remote control signal via the remote control signal receiving circuit 23. Receive. Communication between the remote control and the remote control signal receiving circuit 23 may be either wired communication or wireless communication. When the microcomputer 19 receives the remote control signal, in order to perform an operation with further reduced power consumption in the entire air conditioner, a signal for setting the relay contact 5 in an open state or a closed state according to an operation procedure described below is sent to the relay coil. Output to the drive circuit 20. The relay coil drive circuit 20 controls the energization of the relay exciting coil 6 based on a signal from the microcomputer 19 to make the relay contact 5 open or closed. At this time, the microcomputer 19 controls the open / close state of the relay contact 5 using data stored in advance in the data storage unit 24. As the data storage unit 24, a data storage area inside the microcomputer 19 may be used, or an external memory such as an EEPROM as shown in FIG.

  FIG. 2 shows an operation flow of control executed by the microcomputer 19. Details of the operation procedure will be described with reference to FIG. The operation flow of FIG. 2 is a flow after the AC power supply 1 is turned on to the air conditioner, the relay excitation coil power supply (V1) and the microcomputer drive power supply (V2) are generated as described above, and the microcomputer 19 is started. Applies to operation. It should be noted that after the microcomputer 19 is activated, it has been time since the AC power source 1 was turned on, and no inrush current flows in the inrush current limiting circuit 2.

  When the microcomputer 19 is activated, it enters a remote control standby state in which it is waiting to receive a remote control signal (S11). At this time, since the microcomputer 19 outputs a signal for opening the relay contact 5 to the relay coil drive circuit 20, the relay excitation coil 6 is not energized, and the relay contact 5 is open. For this reason, all the current from the AC power source 1 flows through the NTC thermistor 4.

  When the user operates the remote control, the microcomputer 19 receives a remote control signal via the remote control signal receiving circuit 23 (S12). When the received remote control signal instructs “operation start” (operation start of S13), the relay contact 5 is in an open state, and the operation condition (operation mode: heating / cooling / dehumidification, setting) instructed by the remote controller is set. It is estimated whether or not the temperature of the NTC thermistor 4 of the inrush current limiting circuit 2 is equal to or higher than a specified value when operating at a temperature and an air volume (S14). At this time, since the relay contact 5 is assumed to be operated in an open state, the current of the AC power source 1 is assumed to flow to the NTC thermistor 4 side of the inrush current limiting circuit 2 and the temperature of the NTC thermistor 4 is estimated. become.

  A specific procedure for estimating the temperature of the NTC thermistor 4 is performed as follows. The microcomputer 19 obtains the estimated temperature of the NTC thermistor 4 corresponding to the operating condition instructed by the remote controller by referring to the data stored in the data storage unit 24 in advance. FIG. 3 shows an example of data stored in the data storage unit 24. The data storage unit 24 stores operating conditions and the estimated temperature of the NTC thermistor 4 when the relay contact 5 is opened and operated under this operating condition. Here, the operating conditions are set as “cooling”, “heating”, “dehumidification” as the operation mode, “weak”, “medium”, “strong”, “super strong” as the wind speed, and the set temperature in the range of 16 ° C. to 31 ° C. It is possible to set in units of 1 ℃.

  The data stored in the data storage unit 24 is, for example, in the operation condition S (1), the operation mode = “cooling”, the wind speed = “weak”, and the set temperature = “20 ° C.”. It shows that the estimated temperature of the NTC thermistor 4 is 50 ° C. Similarly, for the other operation conditions S (2) to S (n), the operation conditions including the operation mode, the wind speed, and the set temperature, and the estimated temperature of the NTC thermistor 4 corresponding thereto are stored.

  The microcomputer 19 acquires the estimated temperature Te of the NTC thermistor 4 corresponding to the operating condition instructed by the remote controller from the data storage unit 24. Then, the estimated temperature Te is compared with a threshold temperature Th set in the microcomputer 19 in advance. As will be described later, the threshold temperature Th is a threshold for determining which of the open / closed states of the relay contact 5 can reduce the power consumption of the entire air conditioner, and is determined in advance through experiments, simulations, and the like. It is a value to keep. Here, the threshold temperature Th is 95 ° C. as an example. As a result of comparison, when Te ≧ Th, the microcomputer 19 outputs a signal for opening the relay contact 5 to the relay coil drive circuit 20 so that the relay excitation coil 6 is not energized, and the relay contact 5 is maintained in an open state (S15a).

  On the other hand, when Te <Th, as a result of comparison, the relay excitation coil 6 is energized by outputting a signal from the microcomputer 19 to the relay coil drive circuit 20 to close the relay contact 5 (ON state). 5 is in a closed state (S15b).

  Then, after the open / closed state of the relay contact 5 is determined, the operation of the air conditioner is started under the operating conditions instructed by the remote controller (S16).

  When the received remote control signal instructs “stop operation” (operation stop of S13), if the air conditioner is in operation, the operation of the air conditioner is stopped. If the air conditioner is in a stopped state, the operation state of the air conditioner is maintained (S17). Thereafter, when the operation is stopped, the microcomputer 19 outputs a signal for opening the relay contact 5 to the relay coil drive circuit 20, so that the relay excitation coil 6 is not energized, and the relay contact 5 is turned off. The open state is entered (S18).

  After the process of S16 or S18 is completed, the microcomputer 19 returns to the remote control standby state (S11) in which the remote control signal is waiting to be received, and thereafter the processes of S11 to S18 are repeated.

  The threshold temperature Th may be stored in advance in a memory built in the microcomputer 19, or the threshold temperature Th is stored in advance in the data storage unit 24, and the NTC corresponding to the operating condition instructed by the remote controller. The threshold temperature Th may also be acquired from the data storage unit 24 at the timing when the estimated temperature Te of the thermistor 4 is acquired from the data storage unit 24.

  Next, the effect of the operation of the air conditioner described above will be described. When the air conditioner flows through the inrush current limiting circuit 2, there are two current paths, the current path via the NTC thermistor 4 and the current path via the relay contact 5, depending on whether the relay contact 5 is open or closed. The current path changes.

  When the relay contact 5 is in the closed state (ON state), the current consumption of the air conditioner flows on the relay contact 5 side, so the power consumption in the inrush current limiting circuit 2 is the power consumption at the relay contact 5 and This is the sum of the power consumption (referred to as W1) in the relay exciting coil 6 for bringing the relay contact 5 into the closed state. Since the relay contact 5 has a low resistance value, the power consumption at the relay contact 5 can be regarded as almost zero. Therefore, the power consumption at the inrush current limiting circuit 2 can be regarded as only the power consumption W1 at the relay exciting coil 6.

  On the other hand, when the relay contact 5 is in the open state (OFF state), the current consumption of the air conditioner flows through the NTC thermistor 4 side, so the power consumption in the inrush current limiting circuit 2 is the power consumption in the NTC thermistor 4. Is equal to Here, the power consumption in the NTC thermistor 4 (referred to as W2) is W2 = R × I × I where R is the resistance value of the NTC thermistor 4 and I is the current consumption of the air conditioner.

  When a current flows through the NTC thermistor 4, heat is generated by the resistance component. Due to this self-heating, the temperature of the NTC thermistor 4 itself rises, and the resistance value R of the NTC thermistor 4 decreases due to the temperature characteristic (negative characteristic) of the NTC thermistor. Thus, although the resistance value R of the NTC thermistor 4 decreases as the current consumption of the air conditioner increases, the current consumption of the air conditioner is considerably large, so that even if the resistance value R decreases, W1> It is generally not W2 (for example, W1 = 100 mW, W2 = 720 mW).

  In addition, the NTC thermistor 4 has an inductance component in addition to the resistance component. For this reason, the effect of improving the power factor of the air conditioner is produced by passing the current consumption of the air conditioner through the NTC thermistor 4. When the power factor is improved, the reactive power from the AC power supply 1 is reduced, and thereby the input current from the AC power supply 1 can be reduced. Specifically, due to this power factor improvement effect, the power loss in the diode bridge 8 and the filter circuit 3 inserted in the previous stage (on the AC power supply 1 side) of the diode bridge 8 is greatly reduced.

  For this reason, the power consumption of the inrush current limiting circuit 2 itself is smaller when the relay contact 5 is in the closed state (W1 <W2), but considering the power consumption of the entire air conditioner, the power factor improvement effect described above Therefore, it is possible to reduce the power consumption of the entire air conditioner when the relay contact 5 is in the open state.

  However, when the ambient temperature of the NTC thermistor 4 is low or when the current flowing through the NTC thermistor 4 is small and the self-heating of the NTC thermistor 4 is small, the temperature of the NTC thermistor 4 itself is also suppressed low. Due to this temperature characteristic (negative characteristic), the resistance value R of the NTC thermistor 4 becomes large. For this reason, although there is an effect of reducing the power loss in the diode bridge 8 and the filter circuit 3 which is the power factor improving effect described above, the power consumption W2 in the NTC thermistor 4 becomes very large and the relay contact 5 is closed. It becomes possible to reduce the power consumption of the entire air conditioner.

  That is, the power consumption of the entire air conditioner when the relay contact 5 is opened is the power consumption of the NTC thermistor 4 and the reduction amount of reactive power in the diode bridge 8 and the filter circuit 3 (power factor improvement effect). ). From this point of view, it can be estimated whether the power consumption of the entire air conditioner is smaller when the relay contact 5 is opened or when the relay contact 5 is closed.

  Based on the principle described above, in the present embodiment, the relay contact 5 is based on the estimated temperature of the NTC thermistor 4 under the operating conditions instructed by the remote controller so that the power consumption of the entire air conditioner is further reduced. The open / close state of the is controlled. Specifically, as described above, the estimated temperature of the NTC thermistor 4 under the operating conditions instructed by the remote controller is obtained (FIG. 3), and when this estimated temperature is equal to or higher than a preset threshold temperature Th, the NTC thermistor Since the resistance value R of 4 is small, the power consumption in the NTC thermistor 4 is also small, and the power loss is reduced by the power factor improvement by the NTC thermistor 4, so that the relay contact 5 is opened and the inrush current limiting circuit 2 The power consumption in the whole air conditioner can be reduced by allowing the current inside to flow to the NTC thermistor 4 side.

  For example, in FIG. 3, when the operation conditions are operation mode = “heating”, wind speed = “strong”, and set temperature = “30 ° C.” (S (n)), the air conditioning load is high because the heating is performed at a high temperature setting. The fan speed is high and the load on the fan motor is large due to the wind speed = “strong”. For this reason, current consumption increases and the amount of heat generated in the NTC thermistor 4 increases, which indicates that the estimated temperature of the NTC thermistor 4 increases (100 ° C.). Here, since the threshold temperature Th is 95 ° C., the relay contact 5 is opened in accordance with the operation flow of FIG. 2 so that a current flows to the NTC thermistor 4 side.

  On the other hand, when the estimated temperature of the NTC thermistor 4 is lower than the preset threshold temperature Th, the resistance value R of the NTC thermistor 4 increases and the power consumption in the NTC thermistor 4 increases, so that the power factor of the NTC thermistor 4 increases. Even if there is a power loss reduction effect due to the improvement, the power consumption of the entire air conditioner will increase. For this reason, the power consumption in the whole air conditioner can be reduced by setting the relay contact 5 in the closed state so that the current in the inrush current limiting circuit 2 flows to the relay contact 5 side.

  For example, in FIG. 3, when the operation condition is “cooling”, “super strong”, “16 ° C.” (S (3)), the air conditioning load is high because the cooling is performed at a low temperature setting, and the wind speed is = "Super strong", the fan speed is fast and the fan motor load is large. As a result, the current consumption increases and the amount of heat generated in the NTC thermistor 4 increases, but the temperature of the heat exchanger (not shown) becomes very low due to the cooling operation at the low temperature setting, and the electricity contained in the NTC thermistor 4 The temperature of the NTC thermistor 4 is not so high (65 ° C.) because it works in a direction that suppresses heat generation of the component mounting board. Therefore, according to the operation flow of FIG. 2, the relay contact 5 is closed and current flows to the relay contact 5 side.

  In the process of S18, the reason why the relay contact 5 is in the open state (OFF state) is that the current consumption in the entire air conditioner is small when the operation is stopped, so that the relay contact 5 is closed. This is because the power consumption in the NTC thermistor 4 (for example, W2 <40 mW) is smaller than the power consumption in the relay excitation coil 6 (for example, W1 = 200 mW).

As described above, in the air conditioner provided with the inrush current limiting circuit of the present embodiment,
If the power consumption of the entire air conditioner is smaller when the relay contact 5 is in the open state than when the relay contact 5 is in the closed state, the relay contact 5 is controlled to be in the open state. When the power consumption in the entire air conditioner is smaller than when the relay contact 5 is opened, the relay contact control unit 19 that controls the relay contact 5 to the closed state is provided. did. Specifically, the estimated temperature of the NTC thermistor 4 in the inrush current limiting circuit 2 is obtained from the operating conditions of the air conditioner, and the estimated temperature is compared with a preset threshold temperature, thereby consuming the entire air conditioner. Since the open / close state of the relay contact 5 that can further reduce the electric power is determined, the power consumption of the entire air conditioner can be finely reduced corresponding to the operating condition of the air conditioner.

  Although the control using the threshold temperature Th as the temperature range of the NTC thermistor 4 that can further reduce the power consumption of the entire air conditioner has been described, the preset upper limit temperature Tu is also used as the temperature range together with the threshold temperature Th. May be. This is because if the resistance value of the NTC thermistor 4 becomes too small, the inductance component also becomes small and the current reduction effect due to the power factor improvement becomes small. Therefore, when the estimated temperature Te is higher than the upper limit temperature Tu, the relay contact 5 is closed. This is because the power consumption of the entire air conditioner can be further reduced by setting the state.

  Control parameters other than the operation mode, wind speed, and set temperature settings may be added as operation conditions stored in the data storage unit 24. For example, when the air conditioner has an air cleaning function, the operating state (operating / stopped) of the air cleaning function may be added to the operating conditions.

Embodiment 2.
About the air conditioner in Embodiment 2, operation | movement is demonstrated based on the operation | movement flowchart of FIG. The circuit configuration (FIG. 1) described in the first embodiment is the same except for the control operation performed by the microcomputer 19. In the first embodiment, the temperature of the NTC thermistor 4 in the inrush current limiting circuit 2 is estimated from the operating conditions of the air conditioner, and the relay contact 5 is opened depending on whether or not the estimated temperature is within a specified temperature range. In the second embodiment, instead of the estimated temperature of the NTC thermistor 4, the temperature of the heat exchanger of the air conditioner is used instead of the estimated temperature of the NTC thermistor 4. Are to be switched.

  Since the electric board on which the NTC thermistor 4 is mounted is often disposed in the vicinity of the heat exchanger, the temperature of the heat exchanger and the estimated temperature Te of the NTC thermistor 4, and hence the resistance value R, have a strong correlation. For this reason, when the relay contact 5 is in the open state (OFF state), a specified range of the heat exchanger temperature at which the power consumption of the entire air conditioner is reduced is set in advance, and the measured temperature of the heat exchanger is the specified value. If it is within the range, relay contact 5 is opened (OFF state), current is passed to NTC thermistor 4 side, and if the measured heat exchanger temperature is not within this specified range, relay contact 5 is turned on. The effect similar to that of the first embodiment can be obtained by closing the current (ON state) and allowing the current to flow to the relay contact 5 side.

  FIG. 4 shows an operation flow of control executed by the microcomputer 19. Details of the operation procedure will be described with reference to FIG. Since the processes of S21 to S23 and S27 to S28 are the same as the processes of S11 to S13 and S17 to S18 of FIG. 2, the description thereof will be omitted, and the processes after S24 will be described.

  The microcomputer 19 acquires the temperature of the heat exchanger from a temperature sensor (not shown) installed near the heat exchanger. Since the air conditioner normally includes a temperature sensor in the vicinity of the heat exchanger in order to acquire the heat exchanger temperature necessary for operation control of the air conditioning, this temperature sensor can be utilized. And it is investigated whether this detected heat exchanger temperature is in the preset temperature range (S24).

  This temperature range is a range in which the resistance value of the NTC thermistor 4 is small and the power factor improvement effect by the inductance component of the NTC thermistor 4 is sufficiently obtained when the heat exchanger temperature is within the specified temperature range. It is set as there is.

  When the temperature of the heat exchanger detected by the temperature sensor is within this specified temperature range, the microcomputer 19 outputs a signal for opening the relay contact 5 to the relay coil drive circuit 20. The relay exciting coil 6 is not energized, and the relay contact 5 is kept open (S25a).

  When the heat exchanger temperature is not within the specified temperature range, the microcomputer 19 outputs a signal for setting the relay contact 5 in the closed state (ON state) to the relay coil drive circuit 20, thereby energizing the relay. The coil 6 is energized, and the relay contact 5 is closed (S25b).

  After the processing of S26 or S28 is completed, the microcomputer 19 returns to the remote control standby state (S21) waiting for reception of the remote control signal, and thereafter repeats the processing of S21 to S28.

  As described above, if the resistance value of the NTC thermistor 4 becomes too small, the inductance component also becomes small and the current reduction effect due to the power factor improvement becomes low, so that the specified temperature range of the heat exchanger has an upper limit value. It may be set.

  In addition, when there are a plurality of temperature sensors installed in the vicinity of the heat exchanger, the detection value of the temperature sensor arranged closest to the NTC thermistor 4 may be used, or the average of the detection values of those temperature sensors. A value may be used.

  The air conditioner includes an indoor heat exchanger of the indoor unit and an outdoor heat exchanger of the outdoor unit. When the inrush current limiting circuit 2 is installed in the indoor unit, the vicinity of the indoor heat exchanger When the inrush current limiting circuit 2 is installed in the external unit, a temperature sensor near the outdoor heat exchanger may be used.

  In the above description, the microcomputer 19 can switch the open / closed state of the relay contact 5 when receiving the remote control signal. However, the present invention is not limited to this, and the detected value of the temperature sensor installed in the vicinity of the heat exchanger is periodically displayed. It is also possible to obtain at any time to determine whether this detected value is within a specified temperature range. By doing so, for example, there is an advantage that the open / closed state of the relay contact 5 can be appropriately switched even when the temperature of the heat exchanger greatly changes during the air conditioning operation.

Embodiment 3.
About the air conditioner in Embodiment 3, operation | movement is demonstrated based on the operation | movement flowchart of FIG. In the second embodiment, the temperature of the NTC thermistor 4 is estimated based on the temperature of the heat exchanger, and the open / closed state of the relay contact 5 is determined depending on whether or not the heat exchanger temperature is within a specified temperature range. In the third embodiment, the open / close state of the relay contact 5 is switched using the measured value of the temperature of the NTC thermistor 4 instead of the heat exchanger temperature.

  FIG. 5 shows an operation flow of control executed by the microcomputer 19. Details of the operation procedure will be described with reference to FIG. Since the processes other than S34 are the same as those in FIG. 4, the description thereof will be omitted, and the process of S34 will be described.

  The microcomputer 19 acquires the temperature of the NTC thermistor 4 detected by a temperature sensor (not shown) in the vicinity of the inrush current limiting circuit 2 or installed in the inrush current limiting circuit 2. Then, it is checked whether the detected temperature is within a preset temperature range (S34).

  This temperature range is a range where the resistance value of the NTC thermistor 4 is small when the temperature of the NTC thermistor 4 is within the specified temperature range, and the power factor improvement effect by the inductance component of the NTC thermistor 4 is sufficiently obtained. It is set to be.

  If the detected temperature of the NTC thermistor 4 is within a specified temperature range, the relay contact 5 is opened (S35a), and if the detected temperature is not within the specified temperature range, the relay contact 5 is closed ( S35b).

  In the third embodiment, since the temperature of the NTC thermistor 4 is directly measured, the resistance value of the NTC thermistor 4 can be accurately grasped and more accurate control can be realized. Although the inrush current limiting circuit 2 includes the NTC thermistor 4 and the relay 7, the temperature sensor for measuring the temperature of the NTC thermistor 4 should be installed as close as possible to the NTC thermistor 4.

  Further, the microcomputer 19 can switch the open / closed state of the relay contact 5 when receiving the remote control signal. However, the present invention is not limited to this, and the temperature of the inrush current limiting circuit 2 is periodically acquired to detect this value. It may be determined whether is within a specified temperature range.

Embodiment 4.
About the air conditioner in Embodiment 4, operation | movement is demonstrated based on the operation | movement flowchart of FIG. In the third embodiment, the open / closed state of the relay contact 5 is switched based on the measured temperature value of the NTC thermistor 4 depending on whether or not the measured temperature is within a specified temperature range. In the fourth form, the open / closed state of the relay contact 5 is switched using the measured value of the resistance of the NTC thermistor 4 instead of the measured temperature of the NTC thermistor 4.

  FIG. 6 shows an operation flow of control executed by the microcomputer 19. Details of the operation procedure will be described with reference to FIG. Since the processing other than S44 is the same as the processing in FIG. 5, the description thereof will be omitted, and the processing of S44 will be described.

  The microcomputer 19 acquires the resistance value of the NTC thermistor 4 measured by the resistance value measuring means (not shown) installed in the inrush current limiting circuit 2. Then, it is checked whether or not the measured resistance value is within a preset resistance value range (S44).

  This resistance value range is such that when the resistance value of the NTC thermistor 4 is within the specified resistance value range, the resistance value of the NTC thermistor 4 is small, and the effect of improving the power factor by the inductance component of the NTC thermistor 4 is sufficient. It was set to be within the range obtained.

  If the measured value of the resistance of the NTC thermistor 4 is within this specified range, the relay contact 5 is opened (S35a), and if the measured resistance value is not within the specified range, the relay contact 5 is closed. (S35b).

  As the resistance value measuring means here, for example, a resistance (denoted as auxiliary resistance) having a small temperature dependency is connected in series to the NTC thermistor 4, and the voltage drop at the NTC thermistor 4 and the voltage drop at the auxiliary resistance are respectively determined. By measuring, the resistance value of the NTC thermistor 4 can be calculated.

  In the fourth embodiment, since the resistance value of the NTC thermistor 4 is directly measured, the resistance value of the NTC thermistor 4 can be accurately grasped, and more accurate control can be realized. The microcomputer 19 can switch the open / closed state of the relay contact 5 when receiving the remote control signal. However, the present invention is not limited to this, and the resistance value of the NTC thermistor 4 is periodically acquired and the detected value is obtained. It may be determined whether the temperature is within a specified temperature range.

1 AC power supply, 2 Inrush current limiting circuit, 3 Filter circuit, 4 NTC thermistor, 5 Relay contact, 6 Relay excitation coil, 7 Relay, 8 Diode bridge, 9 Smoothing capacitor, 10 Power transformer, 11 Power supply IC, 12 Voltage generation Diode, 13
Capacitor, 14 transformer secondary side rectifier diode, 15 relay excitation coil power supply capacitor, 16 microcomputer drive power supply IC, 17 microcomputer drive power supply capacitor, 18
Power supply circuit, 19 microcomputer (relay contact control unit), 20 relay coil drive circuit, 21
Fan motor control circuit, 22 fan motor, 23 remote control signal receiving circuit, 24 data storage unit

An air conditioner equipped with an inrush current limiting circuit of the present invention is connected in parallel to an NTC thermistor for limiting an inrush current applied instantaneously when an AC power supply is turned on, and the NTC thermistor, and can be opened and closed In the air conditioner having an inrush current limiting circuit having a relay contact that short-circuits the NTC thermistor in the closed state, the relay contact is opened rather than the relay contact is closed. When power consumption including reactive power in the entire air conditioner is small, the relay contact is controlled to be in an open state, and the relay contact is in a closed state rather than the relay contact is in an open state. If the power consumption including the reactive power of the entire air conditioner is reduced controls the relay contacts closed It is characterized in that it comprises a relay contacts control unit.

Claims (5)

An NTC thermistor that limits an inrush current applied instantaneously when the AC power is turned on, and a relay contact that is connected in parallel to the NTC thermistor and can be opened and closed and short-circuited in the closed state. In an air conditioner equipped with an inrush current limiting circuit having
When the power consumption in the entire air conditioner is smaller when the relay contact is in the open state than when the relay contact is in the closed state, the relay contact is controlled to be in the open state, and the relay contact is When the power consumption of the entire air conditioner is smaller than when the relay contact is opened, the relay contact control unit that controls the relay contact to the closed state is provided. An air conditioner having a featured inrush current limiting circuit.   The relay contact control unit obtains an estimated temperature of the NTC thermistor based on the operating condition of the air conditioner, and compares the estimated temperature with a preset temperature range to open and close the relay contact. It controls, The air conditioner provided with the inrush current limiting circuit of Claim 1.   The relay contact control unit controls opening and closing of the relay contact by comparing a temperature of a heat exchanger of the air conditioner with a preset temperature range. Air conditioner with inrush current limiting circuit.   2. The inrush current limiting circuit according to claim 1, wherein the relay contact control unit controls opening and closing of the relay contact by comparing a temperature of the NTC thermistor with a preset temperature range. Air conditioner equipped with.   2. The inrush current according to claim 1, wherein the relay contact control unit controls opening and closing of the relay contact by comparing a resistance value of the NTC thermistor with a preset resistance value range. Air conditioner with limiting circuit.

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