Noise filter and refrigeration cycle device

Abstract

In a π-type noise filter using a common-mode choke coil, a simple structure is used to suppress deterioration of electromagnetic interference caused by a grounded capacitor. A resistor (54) of a noise filter (50) is arranged between a first input terminal (51a) and a second input terminal (51b) of a common-mode choke coil (51) and a ground line (EC). The resistor (54) is arranged so that current flowing between the first input terminal (51a) and the second input terminal (51b) of the common-mode choke coil (51) and a first output terminal (51x) and a second output terminal (51y) via a first front-stage capacitor (52) or a second front-stage capacitor (53) flows through the resistor (54).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a noise filter and a refrigeration cycle apparatus including the noise filter. BACKGROUND

[0002] Among the noise filters that reduce common mode noise in the past, there is a noise filter that uses a common mode choke coil. In order to reduce common mode noise, a π-type noise filter is sometimes formed using a common mode choke coil, as described in Patent Literature 1 (Japanese Patent Application Publication No. 2017-118387). SUMMARY

[0003] PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In the noise filter described in Patent Literature 1, in the case where the capacitance of the ground capacitor is large, a path through which a noise current returns to a power supply via the ground capacitor is formed, and the effect of reducing the noise current by the common mode choke coil as a component for noise countermeasures is reduced, and electromagnetic interference is deteriorated.

[0005] In the π-type noise filter that uses a common mode choke coil, there is a technical problem of suppressing deterioration of electromagnetic interference caused by a ground capacitor using a simple structure.

[0006] TECHNICAL SOLUTION

[0007] The noise filter of the first aspect includes a ground line, a common mode choke coil, a first front-stage capacitor, a second front-stage capacitor, a first back-stage capacitor, a second back-stage capacitor, and a resistor. The common mode choke coil has first and second input terminals and first and second output terminals, and the first and second input terminals are connected to first and second power supply terminals to which a voltage is applied. The first front-stage capacitor is connected between the first input terminal of the common mode choke coil and the ground line. The second front-stage capacitor is connected between the second input terminal of the common mode choke coil and the ground line. The first back-stage capacitor is connected between the first output terminal of the common mode choke coil and the ground line. The second back-stage capacitor is connected between the second output terminal of the common mode choke coil and the ground line. The resistor is disposed between the first input terminal and the ground line and between the second input terminal and the ground line, or between the first output terminal and the ground line and between the second output terminal and the ground line. The resistor is configured so that a current flowing between the first and second input terminals and the first and second output terminals via the first or second front-stage capacitor flows through the resistor.

[0008] In the noise filter of the first viewpoint, the resistor is arranged so that the current flowing between the first input terminal and the second input terminal and the first output terminal and the second output terminal via the first front-stage capacitor or the second front-stage capacitor flows through the resistor. Thereby, the current of the common mode noise flowing between the first input terminal and the second input terminal and the first output terminal and the second output terminal can be reduced by the resistor.

[0009] The noise filter of the second viewpoint is the noise filter of the first viewpoint, in which the resistor is arranged between the first input terminal and the ground line and between the second input terminal and the ground line.

[0010] In the noise filter of the second viewpoint, by arranging the resistor between the first input terminal and the ground line and between the second input terminal and the ground line, compared with the case of arranging the resistor between the first output terminal and the ground line and between the second output terminal and the ground line, the effect of reducing noise achieved by the first back-stage capacitor and the second back-stage capacitor is prevented from being weakened by the resistor.

[0011] The noise filter of the third viewpoint is the noise filter of the first viewpoint or the second viewpoint, in which the resistor is a thick film chip resistor, a metal plate chip resistor or a ceramic resistor.

[0012] In the noise filter of the third viewpoint, the resistor itself is a thick film chip resistor, a metal plate chip resistor or a ceramic resistor with a high surge voltage resistance, and thus, compared with the case of using a thin film chip resistor with a low surge voltage resistance, it is difficult to occur a failure.

[0013] The noise filter of the fourth viewpoint is the noise filter of any one of the first to third viewpoints, in which a surge absorber is connected in parallel with the first front-stage capacitor and the second front-stage capacitor, and a path from the first power terminal to the ground line via the surge absorber is shorter than a path from the first power terminal to the ground line via the first front-stage capacitor.

[0014] In the noise filter of the fourth viewpoint, a surge current can be discharged by the surge absorber, and thus, a surge voltage applied to the resistor can be reduced.

[0015] The noise filter of the fifth viewpoint is the noise filter of the fourth viewpoint, in which the resistance of the ground line between the surge absorber and the ground is smaller than the resistance of the ground line between the first front-stage capacitor and the ground.

[0016] In the noise filter of the fifth viewpoint, compared with the path via the first front-stage capacitor, a surge current can be rapidly discharged from the noise filter mainly by the surge absorber. As a result, the effect of protecting the resistor from a surge voltage can be improved.

[0017] The noise filter of the sixth aspect is the noise filter of any one of the first to fifth aspects, further including a chip ferrite bead connected in series with the resistor.

[0018] In the noise filter of the sixth aspect, it is expected that high-frequency noise transmitted through the preceding capacitor and the succeeding capacitor is reduced by the chip ferrite bead.

[0019] The refrigeration cycle device of the seventh aspect includes the noise filter of any one of the first to sixth aspects, a power supply module connected to the first output terminal and the second output terminal of the noise filter, and an actuator that operates with supply of electric power from the power supply module.

[0020] In the refrigeration cycle device of the seventh aspect, the current of common-mode noise flowing between the first input terminal and the second input terminal and the first output terminal and the second output terminal can be reduced by the resistor. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic circuit diagram showing an example of the structure of the refrigeration cycle device.

[0022] Figure 2 is a circuit diagram showing an example of the structure of the noise filter of the first embodiment.

[0023] Figure 3 is a schematic circuit diagram for explaining the function of the noise filter.

[0024] Figure 4 is a circuit diagram showing an example of the structure of the noise filter of the modified example 1A.

[0025] Figure 5 is a circuit diagram showing an example of the structure of the noise filter of the modified example 1B.

[0026] Figure 6 is a circuit diagram showing an example of the structure of the noise filter of the modified example 1C.

[0027] Figure 7 is a circuit diagram showing an example of the structure of the noise filter of the modified example 1D.

[0028] Figure 8 is a circuit diagram showing an example of the structure of the noise filter of the second embodiment.

[0029] Figure 9 is a circuit diagram showing an example of the structure of the noise filter of the modified example 2A.

[0030] Figure 10 is a circuit diagram showing an example of the structure of the noise filter of the modified example 2B.

[0031] Figure 11 Fig. 2C is a circuit diagram showing an example of the structure of the noise filter of Modification 2C.

[0032] Figure 12 Fig. 2D is a circuit diagram showing an example of the structure of the noise filter of Modification 2D. DETAILED DESCRIPTION

[0033] <First Embodiment>

[0034] (1) Overall Structure

[0035] Figure 1 An air conditioner 10 as an example of a refrigeration cycle apparatus is shown in Fig. 1. The air conditioner 10 includes an indoor unit 30 and an outdoor unit 20. In the air conditioner 10, the indoor unit 30 and the outdoor unit 20 are connected by refrigerant pipes 12, 13, thereby forming a refrigerant circuit 11. In the refrigerant circuit 11, a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an expansion valve 24, a storage tank 25, and an indoor heat exchanger 31 of the indoor unit 30 are connected. The outdoor unit 20 has the compressor 21, the four-way valve 22, the outdoor heat exchanger 23, the expansion valve 24, the storage tank 25, and an outdoor fan 28. The indoor unit 30 has the indoor heat exchanger 31 and an indoor fan 32. The air conditioner 10 is capable of selectively performing a cooling operation and a heating operation by a vapor compression refrigeration cycle implemented in the refrigerant circuit 11.

[0036] In the cooling operation mode, the four-way valve 22 is switched to the connection state shown by the solid line, thereby connecting the compressor 21 and the outdoor heat exchanger 23 and connecting the indoor heat exchanger 31 and the storage tank 25. In the heating operation mode, the four-way valve 22 is switched to the connection state shown by the broken line, thereby connecting the compressor 21 and the indoor heat exchanger 31 and connecting the outdoor heat exchanger 23 and the storage tank 25.

[0037] The outdoor unit 20 includes the outdoor fan 28, and the indoor unit 30 includes the indoor fan 32. In the cooling operation mode and the heating operation mode, the outdoor fan 28 supplies outdoor air to the outdoor heat exchanger 23 in order to promote heat exchange between the air and the refrigerant in the outdoor heat exchanger 23. Further, in the cooling operation mode and the heating operation mode, the indoor fan 32 supplies indoor air to the indoor heat exchanger 31 in order to promote heat exchange between the air and the refrigerant in the indoor heat exchanger 31.

[0038] The air conditioner 10 includes, for example, a compressor motor 21m that drives the compressor 21, a fan motor 28m that drives the outdoor fan 28, and a fan motor 32m that drives the indoor fan 32 as actuators.

[0039] The air conditioner 10 includes Figure 2The π-type noise filter 50 shown. Figure 2 The noise filter 50 is set for the fan motor 28m. Figure 2 In this example, a noise filter 50 for a fan motor 28m is shown as an example of a noise filter for an actuator in a refrigeration cycle unit. However, other actuators that can use noise filters in a refrigeration cycle unit include, for example, a compressor motor 21m and a fan motor 32m. Therefore, it is also possible to apply noise filters to both the compressor motor 21m and the fan motor 32m. Figure 2 The π-type noise filter 50 is shown. The application of the noise filter 50 to the compressor motor 21m and the fan motor 32m can be performed in the same way as the application of the π-type noise filter to the fan motor 28m. Therefore, the former will be described below and the latter will be omitted.

[0040] (2) Detailed Structure

[0041] The air conditioner 10 drives the compressor motor 21m by receiving a two-phase AC power supply from the AC power source 200. Figure 2 The diagram shows a π-type noise filter 50 and a power module 90 for supplying power to a compressor motor 21m. An AC power supply 200 is connected to the noise filter 50, which is connected to the power module 90, which is in turn connected to the compressor motor 21m. The power module 90 includes a converter 91 and an inverter 92. The AC voltage supplied from the AC power supply 200 is converted to DC voltage by the converter 91, and the DC voltage output from the converter 91 is converted back to AC voltage by the converter 91. The inverter 92 changes the frequency of the power supplied to the compressor motor 21m, thereby changing the speed of the compressor motor 21m. The converter 91 is, for example, a rectifier circuit using a diode bridge.

[0042] The noise filter 50, for example, has the function of suppressing common-mode noise generated by the operation of the power supply module 90. More specifically, the noise filter 50, for example, has the function of suppressing common-mode noise generated by the operation of the inverter 92. By suppressing common-mode noise through the noise filter 50, EMI (electromagnetic interference) is suppressed.

[0043] A grounded wire 202 and an ungrounded wire 201 extend from the AC power supply 200 to the noise filter 50. An AC voltage is applied from the AC power supply 200 between the grounded wire 202 and the ungrounded wire 201.

[0044] (2-1) Noise Filter

[0045] The noise filter 50 includes a common mode choke coil 51, a first front-stage capacitor 52, a second front-stage capacitor 53, a resistor 54, a first rear-stage capacitor 55, and a second rear-stage capacitor 56. The common mode choke coil is sometimes simply referred to as CMCC in the following description.

[0046] The noise filter 50 includes a first power terminal PT1 connected to the ungrounded electric wire 201 and a second power terminal PT2 connected to the grounded electric wire 202. The alternating voltage output from the alternating current power source 200 is applied to the first power terminal PT1 and the second power terminal PT2 of the noise filter 50.

[0047] The first power terminal PT1 is connected to a first input terminal 51a of the CMCC 51. The second power terminal PT2 is connected to a second input terminal 51b of the CMCC 51. First and second output terminals 51x and 51y of the CMCC 51 are connected to the power module 90. More specifically, the first and second output terminals 51x and 51y of the CMCC 51 are connected to an inverter 92 via a converter 91. Thus, the noise filter 50 reduces the noise passing through the first and second power terminals PT1 and PT2 and the noise passing through the noise filter 50 and the power module 90.

[0048] The ground line EC includes a ground wiring EL disposed on the printed wiring board 60 and a ground wire harness EH that is an external equipment of the printed wiring board 60. The end portion of the ground line EC on the printed wiring board 60 is the connection point CP2. The noise filter 50 includes a ground terminal ET to which the ground wire harness EH is attached. The first power terminal PT1, the second power terminal PT2, and the ground terminal ET are disposed on the boundary of the noise filter 50 that separates the inside of the printed wiring board 60 and the outside of the printed wiring board 60. The CMCC 51, the first front-stage capacitor 52, the second front-stage capacitor 53, the resistor 54, the first rear-stage capacitor 55, the second rear-stage capacitor 56, and the wiring such as the ground wiring EL that connects them are disposed in the inside of the printed wiring board 60 of the noise filter 50. The ground wire harness EH is disposed in the outside of the printed wiring board 60 of the noise filter 50.

[0049] The first front-stage capacitor 52 is connected between the first input terminal 51a of the CMCC 51 and the ground wiring EL. The second front-stage capacitor 53 is connected between the second input terminal 51b of the CMCC 51 and the ground wiring EL. The first rear-stage capacitor 55 is connected between the first output terminal 51x of the CMCC 51 and the ground wiring EL. The second rear-stage capacitor 56 is connected between the second output terminal 51y of the CMCC 51 and the ground wiring EL.

[0050] The current flowing between the first input terminal 51a and the second input terminal 51b and the first output terminal 51x and the second output terminal 51y via the first front-stage capacitor 52 or the second front-stage capacitor 53 is caused to flow via the resistor 54. In Figure 2 In the structure of the air conditioner 10, specifically, one terminal of the first front-stage capacitor 52 and one terminal of the second front-stage capacitor 53 are connected at the first connection point CP1, and the resistor 54 is provided between the first connection point CP1 and the ground wiring EL. The connection point of the resistor 54 and the ground wiring EL is the connection point CP2. The connection point CP2 is an end portion of the ground line EC. The first input terminal 51a is connected to the other terminal of the first front-stage capacitor 52, and the second input terminal 51b is connected to the other terminal of the second front-stage capacitor 53.

[0051] The noise filter 50 includes a variable resistor 57 and a surge absorber 58. The variable resistor 57 has a high resistance when a voltage applied thereto is low, but sharply decreases in resistance when reaching a prescribed voltage or more. The surge absorber 58 protects the noise filter 50 and the power supply module 90 from transient abnormal high voltage and abnormal large current. One electrode of the variable resistor 57 is connected to a wiring connecting the first power supply terminal PT1 and the first input terminal 51a of the CMCC 51. The other electrode of the variable resistor 57 is connected to one end of the surge absorber 58. The other end of the surge absorber 58 is connected to a portion of the ground wiring EL between the ground terminal ET and the connection point CP2 of the resistor 54. Note that, here, a case where the surge absorber 58 is provided to the first power supply terminal PT1 is shown, but the surge absorber 58 can also be provided to the second power supply terminal PT2.

[0052] The noise filter 50 has a function of reducing common-mode noise as one of its functions. In the filtering function implemented by the CMCC 51 of the noise filter 50, the inductor functions not against differential-mode but against common-mode.

[0053] A common-mode model is described in Figure 3 In Figure 3 The ground electric wire 202 and the non-ground electric wire 201 are overlapped and represented by one wire. In the common-mode model, a pseudo power circuit network 210 is used. Here, the pseudo power circuit network is sometimes abbreviated as LISN (Line Impedance Stabilization Network).

[0054] In Figure 3In the common mode model, the bypass currents cc1, cc2 flowing between the grounded wire 202 and the ungrounded wire 201 and the ground line EC are indicated by dotted lines. The pseudo power supply circuit network 210 (AC power supply 200) is grounded, the noise filter 50 is grounded through the ground harness EH, and the currents flow through the stray capacitance sc (or parasitic capacitance) generated between the grounded wire 202 and the ungrounded wire 201 and the ground line EC, thereby forming a loop between the grounded wire 202 and the ungrounded wire 201 and the ground line EC. The bypass current cc1 flows in a loop including the LISN 210 (AC power supply 200), the noise filter 50 (except for the ground harness EH), the power supply module 90, the compressor motor 21m, the stray capacitance sc, and the ground line EC. The bypass current cc2 flows in a loop including the power supply module 90, the compressor motor 21m, the stray capacitance sc, the ground line EC, and the ground harness EH including the noise filter 50, the first rear capacitor 55, and the second rear capacitor 56. The bypass current cc1 includes both the current flowing in the loop of the ungrounded wire 201 and the ground line EC and the current flowing in the loop of the grounded wire 202 and the ground line EC.

[0055] If there is no resistor 54, and the capacitances of the first front capacitor 52, the second front capacitor 53, the first rear capacitor 55, and the second rear capacitor 56 of the noise filter 50 are large, the bypass current cc1 bypasses these capacitors. Due to the flow of the bypass current cc1, the higher noise reduction effect of the CMCC 51 cannot be expected. By having the resistor 54 in the noise filter 50, the bypass current cc1 can be reduced, and the higher noise reduction effect of the CMCC 51 can be prevented from not being expected.

[0056] When the resistor 54 is connected in series to the first rear capacitor 55 and the second rear capacitor 56, as when the resistor 54 is connected in series to the first front capacitor 52 and the second front capacitor 53, the resistor 54 prevents the noise entering from the first power terminal PT1 and the second power terminal PT2, thereby preventing the absorption of the external noise from being weakened. In the case where the resistor 54 is connected in series to the first rear capacitor 55 and the second rear capacitor 56, the noise reduction effect of the first rear capacitor 55 and the second rear capacitor 56 is weakened. In contrast, when the resistor 54 is connected in series to the first front capacitor 52 and the second front capacitor 53, the noise reduction effect of the first rear capacitor 55 and the second rear capacitor 56 is prevented from being weakened by the resistor 54.

[0057] In order to reduce the common mode noise, for example, it is also possible to consider configuring a noise filter having a structure in which two ground harnesses are provided instead of the resistor 54, and a ferrite core is disposed on one of the two ground harnesses. As an example of the structure of such a noise filter, the noise filter 50 is changed as follows.Figure 3 The structure following the structure is explained. For Figure 3 The structure of the noise filter is modified so that there are two grounding wire bundles EH, one end of which is connected to the grounding wire EC, and the resistor 54 is not provided. In the modified noise filter structure, the other end of one grounding wire bundle EH is connected to one terminal of the first front capacitor 52 and the second front capacitor 53, and the other end of the grounding wire bundle EH is connected to one terminal of the first rear capacitor 55 and the second rear capacitor 56. At this time, the wiring of the noise filter 50 is connected in the following manner: in the current flow path between one terminal of the first front capacitor 52 and the second front capacitor 53 and one terminal of the first rear capacitor 55 and the second rear capacitor 56, the current flows through one grounding wire bundle EH and the other grounding wire bundle EH. In other words, the wiring is done in a way that one terminal of the first front capacitor 52 and the second front capacitor 53 is not directly connected to one terminal of the first rear capacitor 55 and the second rear capacitor 56. In the modified noise filter structure, the ferrite core is, for example, disposed in the other grounding wire bundle EH. Thus, compared to a π-type noise filter with two grounding wires and a ferrite core, the noise filter 50 described above only requires one grounding wire EH and can reduce the ferrite core, thereby simplifying the structure and reducing costs.

[0058] (2-1-1) Resistor

[0059] Resistor 54 is, for example, a thick-film chip resistor, a metal plate resistor, or a ceramic resistor. In other words, resistor 54 is at least not a thin-film chip resistor. By using a thick-film chip resistor, a metal plate resistor, or a ceramic resistor as resistor 54, surge withstand voltage can be improved.

[0060] (2-1-2) Surge absorber

[0061] Surge absorber 58 is connected in parallel with the first front-end capacitor 52. The path from the first power supply terminal PT1 to the ground wire EC via surge absorber 58 is shorter than the path from the first power supply terminal PT1 to the ground wire EC via the first front-end capacitor. With this structure, the surge voltage entering from the first power supply terminal PT1 is absorbed by surge absorber 58, thus reducing the surge current passing through the first front-end capacitor 52. Noise filter 50 can release surge current through surge absorber 58, thereby reducing the surge voltage applied to resistor 54.

[0062] The length of the ground wiring EL between the surge absorber 58 and the ground is shorter than the length of the ground wiring EL between the first front-stage capacitor 52 and the ground. Therefore, the resistance of the ground wiring EC between the surge absorber 58 and the ground is smaller than the resistance of the ground wiring EC between the first front-stage capacitor 52 and the ground. Likewise, the resistance of the ground wiring EC between the surge absorber 58 and the ground is smaller than the resistance of the ground wiring EC between the second front-stage capacitor 53 and the ground. As a result, the surge current can be quickly discharged from the circuit through the surge absorber 58, as compared to the path via the first front-stage capacitor 52. In addition, the length of the ground wiring EL from the connection point CP3 of the surge absorber 58 and the ground wiring EL to the ground terminal ET is shorter than the length of the ground wiring EL from the connection point CP2 to the ground terminal ET. The shorter length of the ground wiring EL from the connection point CP3 to the ground terminal ET is advantageous in discharging the surge current.

[0063] (3) Modification

[0064] (3-1) Modification 1A

[0065] As Figure 4 indicated, the chip ferrite bead FB can also be connected in series to the resistor 54. The chip ferrite bead FB is mounted on the printed wiring board 60 on which a part of the components of the noise filter 50 is mounted. In Figure 4 , an example is shown in which the chip ferrite bead FB is provided between the second input terminal 51b and the connection point CP2. Figure 4 The noise filter 50 of the above-described first embodiment can expect reduction of high-frequency noise transmitted via the first front-stage capacitor 52, the second front-stage capacitor 53, the first back-stage capacitor 55, and the second back-stage capacitor 56 by the chip ferrite bead FB.

[0066] (3-2) Modification IB

[0067] In the above-described first embodiment, one resistor 54 is provided for the first front-stage capacitor 52 and the second front-stage capacitor 53. However, as Figure 5 indicated, one resistor 54 can also be provided for the first front-stage capacitor 52 and the second front-stage capacitor 53, respectively. In this case, the resistor 54 can also be arranged between the first input terminal 51a and the first front-stage capacitor 52, and the resistor 54 can also be arranged between the second input terminal 51b and the second front-stage capacitor 53. In Figure 5 addition, in this case, the chip ferrite bead FB can be provided for each resistor 54.

[0068] (3-3) Modification 1C

[0069] In the above first embodiment, modification 1A, and modification IB, one or two resistors 54 are provided for the first and second front-stage capacitors 52 and 53. However, as shown in FIG. 10, one resistor 54 can be provided for the first and second back-stage capacitors 55 and 56. In this case, the resistor 54 is arranged between the first output terminal 51x and the first back-stage capacitor 55, and the resistor 54 is arranged between the second output terminal 51y and the second back-stage capacitor 56. In this case, chip ferrite beads FB are provided for the first and second back-stage capacitors 55 and 56. Figure 6

[0070] (3-4) Modification ID

[0071] In the above first embodiment, modification 1C, two resistors 54 are provided for the first and second back-stage capacitors 55 and 56. However, as shown in FIG. 11, one resistor 54 can be provided for the first and second back-stage capacitors 55 and 56. In this case, the resistor 54 is arranged between the first and second back-stage capacitors 55 and 56 and the wiring line EL. In the example shown in FIG. 11, a chip ferrite bead FB is also provided in series with the resistor 54. Figure 7 Figure 7

[0072] <Second Embodiment>

[0073] (4) Overall Structure

[0074] Figure 8 An air conditioner 10 as another example of a refrigeration cycle device is shown in FIG. 12. The air conditioner 10 of the first embodiment receives a supply of electric power from a two-phase alternating-current power source 200. In contrast, the air conditioner 10 of the second embodiment receives a supply of electric power from a three-phase alternating-current power source 300. The alternating-current power source 300 is grounded.

[0075] (5) Noise Filter

[0076] Figure 8 ​​​The noise filter 50 includes a common mode choke coil 51, a first front-stage capacitor 52, a second front-stage capacitor 53, a third front-stage capacitor 71, a resistor 54, a first rear-stage capacitor 55, a second rear-stage capacitor 56, and a third rear-stage capacitor 72. It also includes a first power terminal PT1, a second power terminal PT2, and a third power terminal PT3 connected to an alternating-current power source 300 of three-phase alternating current. An alternating-current voltage is applied from the alternating-current power source 300 to the first power terminal PT1, the second power terminal PT2, and the third power terminal PT3 of the above-described noise filter 50. The first input terminal 51a, the second input terminal 51b, and the third input terminal 51c of the CMCC 51 are connected to the first power terminal PT1, the second power terminal PT2, and the third power terminal PT3. The first output terminal 51x, the second output terminal 51y, and the third output terminal 51z of the CMCC 51 are connected to a power module 90 including an inverter 92 and a converter 91. A compressor motor 21m driven by the three-phase alternating current is connected to the power module 90.

[0077] The first front-stage capacitor 52 is connected between the first input terminal 51a of the CMCC 51 and a ground wiring EL. The second front-stage capacitor 53 is connected between the second input terminal 51b of the CMCC 51 and the ground wiring EL. The third front-stage capacitor 71 is connected between the third input terminal 51c of the CMCC 51 and the ground wiring EL. The first rear-stage capacitor 55 is connected between the first output terminal 51x of the CMCC 51 and the ground wiring EL. The second rear-stage capacitor 56 is connected between the second output terminal 51y of the CMCC 51 and the ground wiring EL. The third rear-stage capacitor 72 is connected between the third output terminal 51z of the CMCC 51 and the ground wiring EL.

[0078] The resistor 54 is provided so that the current flowing between the first input terminal 51a, the second input terminal 51b, and the third input terminal 51c and the first output terminal 51x, the second output terminal 51y, and the third output terminal 51z via the first front-stage capacitor 52, the second front-stage capacitor 53, and the third front-stage capacitor 71 flows through the resistor 54. In Figure 8 In the structure of the air conditioner 10, specifically, one terminal of the first front-stage capacitor 52, one terminal of the second front-stage capacitor 53, and one terminal of the third front-stage capacitor 71 are connected at a first connection point CP1, and the resistor 54 is provided between the first connection point CP1 and the ground wiring EL. The connection point of the resistor 54 with the ground wiring EL is a connection point CP2. The first input terminal 51a is connected to the other terminal of the first front-stage capacitor 52, the second input terminal 51b is connected to the other terminal of the second front-stage capacitor 53, and the third input terminal 51c is connected to the other terminal of the third front-stage capacitor 71.

[0079] The noise filter 50 includes three varistors 57 provided for the first power terminal PT1, the second power terminal PT2, and the third power terminal PT3, and a surge absorber 58 connected to the three varistors 57. One electrode of each of the three varistors 57 is connected to the first power terminal PT1, the second power terminal PT2, and the third power terminal PT3, respectively, and the other electrodes of the three varistors 57 are all connected to one end of the surge absorber 58. The other end of the surge absorber 58 is connected to a portion of the ground wiring EL between the ground terminal ET and the connection point CP2 of the resistor 54.

[0080] The kind of the resistor for the resistor 54 and the configuration of the surge absorber 58 for the second embodiment are the same as those of the first embodiment, and thus the description thereof is omitted here. Further, the common mode of the stray capacitance sc of the second embodiment is also the same as that of the first embodiment, and thus the description thereof is omitted.

[0081] (6) Modification

[0082] (6-1) Modification 2A

[0083] As Figure 9 indicated, it is also possible to connect the chip ferrite beads FB in series to the resistor 54. The chip ferrite beads FB are mounted on the printed wiring board 60 on which a part of the components of the noise filter 50 is mounted. In Figure 9 , an example is shown in which the chip ferrite beads FB are provided between the second input terminal 51b and the connection point CP2. Figure 9 The noise filter 50 of the second embodiment described above can expect reduction of high-frequency noise transmitted through the first front-stage capacitor 52, the second front-stage capacitor 53, the third front-stage capacitor 71, the first back-stage capacitor 55, the second back-stage capacitor 56, and the third back-stage capacitor 72 by the chip ferrite beads FB.

[0084] (6-2) Modification 2B

[0085] In the second embodiment described above, one resistor 54 is provided for the first front-stage capacitor 52, the second front-stage capacitor 53, and the third front-stage capacitor 71. However, as Figure 10 indicated, one resistor 54 can be provided for each of the first front-stage capacitor 52, the second front-stage capacitor 53, and the third front-stage capacitor 71. In this case, the resistor 54 can also be arranged between the first input terminal 51a and the first front-stage capacitor 52, between the second input terminal 51b and the second front-stage capacitor 53, and between the third input terminal 51c and the third front-stage capacitor 71. Further, the chip ferrite beads FB can be provided for each of the resistors 54.

[0086] (6-3) Modification 2C

[0087] In the above-described second embodiment, Modification 2A, and Modification 2B, one or two resistors 54 are provided for the first, second, and third front-stage capacitors 52, 53, and 71. However, as shown in Modification 2D, one resistor 54 can be provided for the first, second, and third front-stage capacitors 52, 53, and 71. In this case, the resistor 54 is disposed between the first, second, and third front-stage capacitors 52, 53, and 71 and the connection wiring EL. Figure 11 In this case, the resistor 54 can be disposed between the first, second, and third front-stage capacitors 52, 53, and 71 and the connection wiring EL. In the example shown in Modification 2D, a chip ferrite bead FB is also provided in series with the resistor 54.

[0088] (6-4) Modification 2D

[0089] In the above-described second embodiment, Modification 2C, three resistors 54 are provided for the first, second, and third back-stage capacitors 55, 56, and 72. However, as shown in Modification 2D, one resistor 54 can be provided for the first, second, and third back-stage capacitors 55, 56, and 72. In this case, the resistor 54 is disposed between the first, second, and third back-stage capacitors 55, 56, and 72 and the connection wiring EL. Figure 12 In this case, the resistor 54 can be disposed between the first, second, and third front-stage capacitors 52, 53, and 71 and the connection wiring EL. In the example shown in Modification 2D, a chip ferrite bead FB is also provided in series with the resistor 54. Figure 12

[0090] (7) Features

[0091] (7-1)

[0092] ​In the noise filter 50, a current flows between the first input terminal 51a and the second input terminal 51b through the first front-stage capacitor 52 or the second front-stage capacitor 53, and between the first output terminal 51x and the second output terminal 51y. Alternatively, in the noise filter 50, a current flows between the first input terminal 51a, the second input terminal 51b, and the third input terminal 51c through the first front-stage capacitor 52, the second front-stage capacitor 53, or the third front-stage capacitor 71, and between the first output terminal 51x, the second output terminal 51y, and the third output terminal 51z. The resistor 54 is provided so that the current flows through the resistor 54. Thus, the current can be reduced by the resistor 54. As a result, it is possible to prevent the effect of reducing common-mode noise by the CMCC 51 from being unable to be expected. Therefore, in the noise filter 50, it is possible to suppress the deterioration of electromagnetic interference caused by the capacitors to the ground using a simple structure.

[0093] (7-2)

[0094] In the noise filter 50, the resistor 54 is arranged between the first input terminal 51a and the ground line EC and between the second input terminal 51b and the ground line EC. In this case, compared with the case where the resistor 54 is arranged between the first output terminal 51x and the ground line EC and between the second output terminal 51y and the ground line EC, the effect of reducing noise achieved by the first rear-stage capacitor 55 and the second rear-stage capacitor 56 is prevented from being weakened by the resistor 54.

[0095] (7-3)

[0096] The resistor 54 of the noise filter 50 is a thick-film chip resistor, a metal plate chip resistor, or a ceramic resistor. The surge withstand voltage of the resistor itself of such a resistor 54 is high, and thus, compared with the case where a thin-film chip resistor or the like having a low surge withstand voltage is used, it is difficult to malfunction.

[0097] (7-4)

[0098] In the noise filter 50, the path from the first power terminal PT1 to the ground line EC via the surge absorber 58 is shorter than the path from the first power terminal PT1 to the ground line EC via the first front-stage capacitor 52. Therefore, compared with the path via the first front-stage capacitor 52, it is possible to quickly release a surge current from the noise filter 50 mainly by the surge absorber 58.

[0099] (7-5)

[0100] The noise filter 50 described above is configured such that the resistance of the ground line EC between the surge absorber 58 and the ground is smaller than the resistance of the ground line EC between the first front-stage capacitor 52 and the ground. In this configuration, a surge current can be quickly discharged from the noise filter 50 mainly through the surge absorber 58, compared to the path via the first front-stage capacitor 52.

[0101] (7-6)

[0102] The noise filter 50 described above, in a case where a chip ferrite bead FB is connected in series with the resistor 54, can expect reduction of high-frequency noise transmitted via the first front-stage capacitor 52, the second front-stage capacitor 53, the third front-stage capacitor 71, the first back-stage capacitor 55, the second back-stage capacitor 56, and the third back-stage capacitor 72 by the chip ferrite bead FB.

[0103] (7-7)

[0104] The air conditioner 10, which is an example of a refrigeration cycle device, includes the noise filter 50 described above, a power supply module 90 connected to the first output terminal 51x and the second output terminal 51y of the noise filter 50, and a compressor motor 21m or a fan motor 28m, which are actuators that operate by receiving a supply of electric power from the power supply module 90. The refrigeration cycle device is a device that performs a refrigeration cycle using a refrigerant. As the refrigeration cycle device, in addition to the air conditioner 10, there are, for example, a refrigerator, a freezer, a water heater, a floor heating device, and a heat pump device. Further, the actuators include solenoids in addition to motors.

[0105] In the noise filter 50 of the air conditioner 10, the current of the common-mode noise flowing between the first input terminal 51a and the second input terminal 51b and the first output terminal 51x and the second output terminal 51y through the first front-stage capacitor 52 or the second front-stage capacitor 53 is reduced by the resistor 54. Thereby, it is possible to prevent a reduction in the suppression effect on the common-mode noise generated in the power supply module 90 or the compressor motor 21m or the fan motor 28m, which are actuators.

[0106] The embodiments of the present disclosure have been described above, but it should be understood that various modifications in form and details can be made without departing from the spirit and scope of the present disclosure recited in the claims.

[0107] Explanation of Symbols

[0108] 10 Air conditioner (example of refrigeration cycle device);

[0109] 21m Compressor motor (example of actuator);

[0110] 28m, 32m Fan motor (example of actuator);

[0111] 50 noise filter;

[0112] 51 common mode choke coil;

[0113] 51a first input terminal;

[0114] 51b second input terminal;

[0115] 51x first output terminal;

[0116] 51y second output terminal;

[0117] 52 first front-stage capacitor;

[0118] 53 second front-stage capacitor;

[0119] 54 resistor;

[0120] 55 first back-stage capacitor;

[0121] 56 second back-stage capacitor;

[0122] 58 surge absorber;

[0123] 90 power supply module;

[0124] EC ground line;

[0125] FB chip ferrite bead;

[0126] PT1 first power supply terminal;

[0127] PT2 second power supply terminal.

[0128] Prior art document

[0129] Patent document

[0130] Patent document 1: Japanese Patent Application Publication No. 2017-118387

Claims

1. A noise filter (50), characterized in that, include: Grounding wire (EC); A common-mode choke coil (51) has a first input terminal (51a) and a second input terminal (51b), as well as a first output terminal (51x) and a second output terminal (51y). The first input terminal and the second input terminal are connected to a first power supply terminal (PT1) and a second power supply terminal (PT2) to which a voltage is applied. The first front capacitor (52) is connected between the first input terminal of the common mode choke coil and the ground wire; The second front capacitor (53) is connected between the second input terminal of the common mode choke coil and the ground wire; The first post-capacitor (55) is connected between the first output terminal of the common-mode choke coil and the ground wire; The second post-capacitor (56) is connected between the second output terminal of the common-mode choke coil and the ground wire; Resistor (54), the resistor is disposed between the first input terminal and the ground wire and between the second input terminal and the ground wire, or disposed between the first output terminal and the ground wire and between the second output terminal and the ground wire; as well as A surge absorber (58) is connected in parallel with the first front-end capacitor. The resistor is configured such that current flowing between the first input terminal and the second input terminal and the first output terminal and the second output terminal, passing through the first front-end capacitor or the second front-end capacitor, flows through the resistor. The path from the first power terminal to the ground wire via the surge absorber is shorter than the path from the first power terminal to the ground wire via the first front capacitor. The resistance of the grounding wire between the surge absorber and the ground is less than the resistance of the grounding wire between the first front capacitor and the ground.

2. The noise filter (50) according to claim 1, characterized in that, The resistor is positioned between the first input terminal and the ground wire, and between the second input terminal and the ground wire.

3. The noise filter (50) according to claim 1 or 2, characterized in that, The resistor is disposed between the first input terminal and the ground wire, and between the second input terminal and the ground wire. The path from the first power terminal to the ground wire via the surge absorber is shorter than the path from the first power terminal to the ground wire via the first front capacitor and the resistor.

4. The noise filter (50) according to claim 1 or 2, characterized in that, The grounding wire includes: a grounding wiring (EL) disposed on a printed wiring board (60) and having a grounding terminal (ET); and a grounding harness (EH) consisting of wires mounted to the grounding terminal. The length of the grounding wiring from the third connection point (CP3) to the grounding terminal is shorter than the length of the grounding wiring from the second connection point (CP2) to the grounding terminal, wherein the third connection point is the connection point of the grounding wiring with the path from the first power terminal through the surge absorber to the grounding wire, and the second connection point is the connection point of the grounding wiring with the path from the first power terminal through the first front capacitor to the grounding wire.

5. The noise filter (50) according to claim 1 or 2, characterized in that, The resistor is a thick-film resistor, a metal plate resistor, or a ceramic resistor.

6. The noise filter (50) according to claim 1 or 2, characterized in that, The noise filter includes a chip ferrite bead (FB) connected in series with the resistor.

7. A refrigeration circulation device (10), characterized in that, include: The noise filter (50) of claim 1 or 2; A power supply module (90) is connected to the first output terminal and the second output terminal of the noise filter; as well as Actuators (21m, 28m) that receive power from the power module and operate accordingly.

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