ACDC converter

Abstract

To provide an ACDC converter that suppresses the increase in radiated noise regardless of a structure of a housing.SOLUTION: An ACDC converter 30 includes a housing 70 that houses a first rectifier 31, a second rectifier 32, a first capacitor 41, a second capacitor 42, a third capacitor 43, a fourth capacitor 44, a first coil 51, a second coil 52, and a bypass path 55, and the bypass path 55 is connected between the first capacitor 41 and the second capacitor 42 and between the third capacitor 43 and the fourth capacitor 44.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an AC / DC converter. [Background technology]

[0002] Conventionally, as described in Patent Document 1, there is known a wireless power supply device including a rectifier circuit section having three rectifier coils and two diodes. This rectifier circuit section rectifies high-frequency power from a high-frequency power supply section to convert it to direct current. The power converted to direct current by the rectifier circuit section is stored in a power storage section through a control circuit section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-137180 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the rectifier circuit section described in Patent Document 1, rectification by the diode causes noise currents of the same phase to flow in the same direction from the diode on the positive and negative sides of the high frequency power supply section, and return to the diode via the ground. At this time, the paths of the noise currents are in the same direction, so a relatively large amount of radiation noise is generated. Therefore, in order to reduce the noise current and radiation noise, the rectifier circuit section may be housed in a metal case, and a Y capacitor connected to the metal case and the input / output terminals of the rectifier circuit section may be provided. When this Y capacitor is provided, a part of the noise current from the diode passes through the Y capacitor, so that the noise current passing from the diode to the ground is reduced. This reduces the radiation noise. However, depending on the structure of the metal case, the distance between the metal case and the Y capacitor becomes long, so that the impedance in the path of the noise current passing from the diode to the Y capacitor becomes high. If the impedance in this path is high, the noise current passing from the diode to the Y capacitor is reduced. As a result, the noise current passing from the diode to the ground increases. Therefore, even if the Y capacitor is provided, the radiation noise increases depending on the structure of the metal case.

[0005] An object of the present disclosure is to provide an AC / DC converter that suppresses an increase in radiated noise regardless of the structure of the housing. [Means for solving the problem]

[0006] The invention described in claim 1 includes a first rectifier (31) that outputs a positive portion of an AC current from an AC power source (15) to a load (20), a second rectifier (32) that converts the AC current to a DC current together with the first rectifier by outputting a negative portion of the AC current to the load, a first capacitor (41) connected in parallel with the first rectifier and the second rectifier and connected to the side of the first rectifier opposite the second rectifier, a second capacitor (42) connected in series with the first capacitor and connected to the side of the second rectifier opposite the first rectifier, a third capacitor (43) connected in parallel with the load and connected between the first rectifier and the second rectifier, and a third capacitor (44) connected in series with the third capacitor and connected to the side of the load opposite the third capacitor. a fourth capacitor (44) connected to the first rectifier, a first coil (51) connected to the side of the first rectifier opposite to the second rectifier and smoothing the output from the second rectifier together with the third capacitor and the fourth capacitor, a second coil (52) connected to the side of the second rectifier opposite to the first rectifier and smoothing the output from the first rectifier together with the third capacitor and the fourth capacitor, a bypass path (55) connected between the first capacitor and the second capacitor and between the third capacitor and the fourth capacitor, and a housing (70) that houses the first rectifier, the second rectifier, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the first coil, the second coil, and the bypass path.

[0007] Since the bypass path is one current path accommodated in the housing, the impedance of the bypass path is lower than the impedance of the path of the noise current passing from the first rectifier and the second rectifier to the ground. Therefore, the noise current from the first rectifier and the second rectifier is likely to flow to the bypass path via the first capacitor or the second capacitor. In addition, the noise current that has flowed through the bypass path passes through the third capacitor or the fourth capacitor. Therefore, since the noise current from the first rectifier and the second rectifier flows to the bypass path, the noise current passing from the first rectifier and the second rectifier to the ground is reduced. This suppresses an increase in radiation noise. In addition, there is no need to connect the bypass path to the housing. Therefore, an increase in radiation noise is suppressed regardless of the structure of the housing.

[0008] The invention described in claim 6 is an AC / DC converter including a first rectifier (31) that outputs a positive portion of an AC current from an AC power source (15) to a load (20), a second rectifier (32) that converts the AC current to a DC current together with the first rectifier by outputting a negative portion of the AC current to the load, a capacitor that is connected in parallel with the load and between the first rectifier and the second rectifier, and a first coil (51) that is connected on the side of the first rectifier opposite to the second rectifier and that smoothes an output from the second rectifier together with the capacitor. The ACDC converter includes a second coil (52) connected to the side of the second rectifier opposite the first rectifier and smoothing the output from the first rectifier together with a capacitor, a third coil (53) connected between the first rectifier and the second rectifier and to the capacitor, and a housing (70) that houses the first rectifier, the second rectifier, the capacitor, the first coil, the second coil, and the third coil, wherein the inductance (Lc3) of the third coil is greater than the inductance (Lc1) of the first coil and the inductance (Lc2) of the second coil.

[0009] As a result, compared to when the inductances of the first coil, the second coil, and the third coil are the same, the difference between the current flowing through the first coil and the third coil and the current flowing through the second coil and the third coil when AC current is converted to DC current is smaller. This prevents the current balance with respect to the ground from being disrupted. This prevents the generation of noise currents. This prevents the generation of radiated noise. In addition, there is no need to connect the third coil to the housing. This prevents the increase in radiated noise regardless of the structure of the housing.

[0010] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a power conversion system in which an AC-DC converter according to a first embodiment is used. [Diagram 2] A diagram showing the flow of current when an AC / DC converter converts AC to DC. [Diagram 3] A diagram showing the flow of current when an AC / DC converter converts AC to DC. [Figure 4] FIG. 13 is a diagram showing the flow of noise current in a comparative example. [Diagram 5] A diagram showing the noise current flowing through the bypass path of the AC / DC converter. [Figure 6] FIG. 13 is a diagram showing the relationship between the presence or absence of a bypass path, the frequency of the noise current, the noise current passing through the ground, and the radiated noise. [Figure 7] A diagram showing the flow of current when an AC / DC converter converts AC to DC. [Figure 8] A diagram showing the flow of current when an AC / DC converter converts AC to DC. [Figure 9] FIG. 11 is a configuration diagram of a power conversion system in which an AC-DC converter according to a second embodiment is used. [Figure 10]FIG. 11 is a configuration diagram of a power conversion system in which an AC-DC converter according to a third embodiment is used. [Figure 11] FIG. 13 is a configuration diagram of a power conversion system in which an AC-DC converter according to a fourth embodiment is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and the description thereof will be omitted.

[0013] (First embodiment) In the AC-DC converter of this embodiment, the increase in radiation noise is suppressed regardless of the structure of the housing. The AC-DC converter is also used in a power conversion system that converts AC current into DC current. First, this power conversion system will be described.

[0014] As shown in FIG. 1, a power conversion system 10 includes an AC power source 15, a load 20, and an AC / DC converter 30.

[0015] The AC power supply 15 has, for example, an inverter or the like, and generates an AC current. The AC power supply 15 is also connected to the ground 18 via a parasitic capacitor 17. The load 20 is, for example, a power storage device or the like. The load 20 is also connected to the ground 18 via the parasitic capacitor 17.

[0016] The ACDC converter 30 includes a first rectifier 31, a second rectifier 32, a first capacitor 41, a second capacitor 42, a third capacitor 43, and a fourth capacitor 44. The ACDC converter 30 also includes a first coil 51, a second coil 52, a third coil 53, a bypass path 55, a first conversion coil 61, a second conversion coil 62, and a housing 70.

[0017] The first rectifier 31 and the second rectifier 32 are diodes. The first rectifier 31 outputs a positive portion of the AC current from the AC power supply 15 to the load 20. The cathode of the second rectifier 32 is connected to the cathode of the first rectifier 31. Furthermore, the second rectifier 32 outputs a negative portion of the AC current from the AC power supply 15 to the load 20. Thus, the second rectifier 32, together with the first rectifier 31, converts the AC current from the AC power supply 15 into a DC current.

[0018] The first capacitor 41 is connected in parallel to the first rectifier 31 and the second rectifier 32. One end of the first capacitor 41 is connected to the side of the first rectifier 31 opposite to the second rectifier 32, that is, to the anode of the first rectifier 31 here.

[0019] The second capacitor 42, together with the first capacitor 41, is connected in parallel with the first rectifier 31 and the second rectifier 32. Furthermore, one end of the second capacitor 42 is connected in series with the other end of the first capacitor 41. Moreover, the other end of the second capacitor 42 is connected to the side of the second rectifier 32 opposite to the first rectifier 31, here, to the anode of the second rectifier 32.

[0020] The third capacitor 43 is connected in parallel with the load 20. Furthermore, one end of the third capacitor 43 is connected between the cathode of the first rectifier 31 and the cathode of the second rectifier 32 via a third coil 53 described later. Furthermore, one end of the third capacitor 43 is connected to one end of the load 20 via a first output terminal 711 of a housing 70 described later.

[0021] The fourth capacitor 44, together with the third capacitor 43, is connected in parallel to the load 20. Furthermore, one end of the fourth capacitor 44 is connected in series to the other end of the third capacitor 43. Moreover, the other end of the fourth capacitor 44 is connected to the other end of the load 20 via a second output terminal 712 of the housing 70, which will be described later.

[0022] One end of the first coil 51 is connected to the anode of the first rectifier 31 and one end of the first capacitor 41. Furthermore, the other end of the first coil 51 is connected to the other end of the fourth capacitor 44. The first coil 51 forms an LC circuit together with the third capacitor 43 and the fourth capacitor 44. As a result, the first coil 51 smoothes the output from the second rectifier 32 together with the third capacitor 43 and the fourth capacitor 44, as described below.

[0023] One end of the second coil 52 is connected to the anode of the second rectifier 32 and the other end of the second capacitor 42. Furthermore, the other end of the second coil 52 is connected to the other end of the fourth capacitor 44 and the other end of the first coil 51. Furthermore, the second coil 52 forms an LC circuit together with the third capacitor 43 and the fourth capacitor 44. As a result, the second coil 52 smoothes the output from the first rectifier 31 together with the third capacitor 43 and the fourth capacitor 44, as described below.

[0024] One end of the third coil 53 is connected between the cathode of the first rectifier 31 and the cathode of the second rectifier 32. Furthermore, the other end of the third coil 53 is connected to one end of the third capacitor 43. The third coil 53 forms an LC circuit together with the third capacitor 43, the fourth capacitor 44, the first coil 51, and the second coil 52. As a result, the third coil 53 smoothes the outputs from the first rectifier 31 and the second rectifier 32, as described later.

[0025] Here, the inductance of the first coil 51 is a first inductance Lc1, the inductance of the second coil 52 is a second inductance Lc2, and the inductance of the third coil 53 is a third inductance Lc3.

[0026] The third inductance Lc3 is larger than the first inductance Lc1 and the second inductance Lc2, i.e., Lc3>Lc1, Lc3>Lc2. The first inductance Lc1 and the second inductance Lc2 may be the same or different. That is, Lc1=Lc2 or Lc1≠Lc2 may be satisfied.

[0027] The bypass path 55 is a wiring or the like. One end of the bypass path 55 is connected between the first capacitor 41 and the second capacitor 42, and is connected to the other end of the first capacitor 41 and one end of the second capacitor 42 here. Furthermore, the other end of the bypass path 55 is connected between the third capacitor 43 and the fourth capacitor 44, and is connected to the other end of the third capacitor 43 and one end of the fourth capacitor 44 here.

[0028] One end of the first conversion coil 61 is connected to the side of the first rectifier 31 opposite to the second rectifier 32, here, to the anode of the first rectifier 31. Also, one end of the first conversion coil 61 is connected to the side of the first capacitor 41 opposite to the second capacitor 42, here, to one end of the first capacitor 41. Furthermore, one end of the first conversion coil 61 is connected to one end of the first coil 51.

[0029] One end of the second transducer coil 62 is connected to the side of the second rectifier 32 opposite to the first rectifier 31, here, the anode of the second rectifier 32. Furthermore, one end of the second transducer coil 62 is connected to the side of the second capacitor 42 opposite to the first capacitor 41, here, the other end of the second capacitor 42. Also, one end of the second transducer coil 62 is connected to one end of the second coil 52. Furthermore, the second transducer coil 62 constitutes an impedance conversion circuit together with the first capacitor 41, the second capacitor 42, and the first transducer coil 61. The impedance conversion circuit constituted by these performs impedance matching between the AC power supply 15 and the load 20.

[0030] The housing 70 is made of metal or the like and is therefore conductive. The housing 70 also houses the first rectifier 31, the second rectifier 32, the first capacitor 41, the second capacitor 42, the third capacitor 43 and the fourth capacitor 44. The housing 70 also houses the first coil 51, the second coil 52, the third coil 53, the bypass path 55, the first transducer coil 61 and the second transducer coil 62. The housing 70 also has a first input terminal 701, a second input terminal 702, a first output terminal 711 and a second output terminal 712.

[0031] The first input terminal 701 is connected to one end of the AC power supply 15. Furthermore, the first input terminal 701 is connected to the other end of the first conversion coil 61.

[0032] The second input terminal 702 is connected to the other end of the AC power supply 15. The second input terminal 702 is also connected to the other end of the second conversion coil 62.

[0033] The first output terminal 711 is connected to one end of the load 20. Furthermore, the first output terminal 711 is connected to one end of the third capacitor 43 and the other end of the third coil 53.

[0034] The second output terminal 712 is connected to the other end of the load 20. The second output terminal 712 is also connected to the other end of the fourth capacitor 44, the other end of the first coil 51, and the other end of the second coil 52.

[0035] As described above, the power conversion system 10 including the AC / DC converter 30 of the first embodiment is configured. Next, conversion from AC current to DC current by the AC / DC converter 30 will be described.

[0036] Here, the direction of current flowing from AC power supply 15 to first input terminal 701 is defined as a positive direction, and the direction of current flowing from AC power supply 15 to second input terminal 702 is defined as a negative direction.

[0037] Then, an AC current is generated by the AC power supply 15. The generated AC current flows through an impedance conversion circuit formed by the first capacitor 41, the second capacitor 42, the first conversion coil 61, and the second conversion coil 62. The impedance conversion circuit formed by these components performs impedance matching between the AC power supply 15 and the load 20.

[0038] When the direction of the current from the AC power source 15 is positive, as shown in FIG. 2, the current flows from the AC power source 15 to the first rectifier 31 via the first input terminal 701 and the first conversion coil 61. At this time, the first rectifier 31 outputs a positive portion of the AC current from the AC power source 15 to the load 20, and outputs a current to the load 20 via the third coil 53 and the first output terminal 711. Furthermore, the current flowing to the load 20 flows to the AC power source 15 via the second output terminal 712, the second coil 52, the second conversion coil 62, and the second input terminal 702. At this time, the current flowing to the load 20 is smoothed by the LC circuit formed by the second coil 52, the third coil 53, the third capacitor 43, and the fourth capacitor 44. In FIG. 2, the current flow is indicated by a two-dot chain line.

[0039] Also, when the direction of the current from the AC power source 15 is negative, as shown in FIG. 3, the current flows from the AC power source 15 to the second rectifier 32 via the second input terminal 702 and the second conversion coil 62. At this time, the second rectifier 32 outputs the negative part of the AC current from the AC power source 15 to the load 20, and therefore outputs the current to the load 20 via the third coil 53 and the first output terminal 711. As a result, the second rectifier 32, together with the first rectifier 31, converts the AC current from the AC power source 15 into a DC current. Furthermore, the current flowing to the load 20 flows to the AC power source 15 via the second output terminal 712, the first coil 51, the first conversion coil 61, and the first input terminal 701. At this time, the current flowing to the load 20 is smoothed by the LC circuit formed by the first coil 51, the third coil 53, the third capacitor 43, and the fourth capacitor 44. In FIG. 3, the flow of current is indicated by a two-dot chain line.

[0040] As described above, the AC / DC converter 30 converts AC current into DC current. Next, how the AC / DC converter 30 suppresses an increase in radiation noise regardless of the structure of the housing 70 will be described.

[0041] Here, as in the comparative ACDC converter 90 shown in FIG. 4, a plurality of Y capacitors 100 may be provided. The Y capacitor 100 is connected to the housing 70. The Y capacitor 100 is also connected to the first input terminal 701, the second input terminal 702, the first output terminal 711, and the second output terminal 712, respectively. However, depending on the housing 70, the distance between the housing 70 and the Y capacitor 100 becomes long, and the impedance in the path of the noise current passing from the first rectifier 31 and the second rectifier 32 to the Y capacitor 100 becomes high. If the impedance in this path is high, the noise current passing from the first rectifier 31 and the second rectifier 32 to the Y capacitor 100 is reduced. Therefore, the noise current passing from the first rectifier 31 and the second rectifier 32 through the ground 18 increases. Therefore, even if the Y capacitor 100 is provided, the radiation noise increases depending on the structure of the housing 70. 4, the noise current passing from the first rectifier 31 and the second rectifier 32 through the Y capacitor 100 is indicated by a two-dot chain line. Also, the noise current passing from the first rectifier 31 and the second rectifier 32 through the ground 18 is indicated by a dashed line.

[0042] 1, the AC / DC converter 30 of this embodiment includes a bypass path 55. The bypass path 55 is connected between the first capacitor 41 and the second capacitor 42 and between the third capacitor 43 and the fourth capacitor 44.

[0043] Since the bypass path 55 is one current path accommodated in the housing 70, the impedance of the bypass path 55 is lower than the impedance of the path of the noise current passing from the first rectifier 31 and the second rectifier 32 to the ground 18. Therefore, as shown in FIG. 5, the noise current from the first rectifier 31 and the second rectifier 32 is likely to flow to the bypass path 55 via the first capacitor 41 or the second capacitor 42. Furthermore, the noise current that has flowed through the bypass path 55 passes through the third capacitor 43 or the fourth capacitor 44. In FIG. 5, the noise current passing from the first rectifier 31 and the second rectifier 32 to the bypass path 55 is indicated by a two-dot chain line. Furthermore, the noise current passing from the first rectifier 31 and the second rectifier 32 through the ground 18 is indicated by a dashed line.

[0044] Therefore, since the noise current from the first rectifier 31 and the second rectifier 32 flows through the bypass path 55, the noise current passing from the first rectifier 31 and the second rectifier 32 through the ground 18 is reduced as shown in Fig. 6. This suppresses an increase in radiation noise. Also, there is no need to connect the bypass path 55 to the housing 70. Therefore, regardless of the structure of the housing 70, an increase in radiation noise is suppressed.

[0045] Furthermore, the AC / DC converter 30 of the first embodiment has the following advantages.

[0046] [1-1] The ACDC converter 30 includes a first converter coil 61 and a second converter coil 62, as shown in Fig. 1. The first converter coil 61 is connected to the first rectifier 31 on the side opposite to the second rectifier 32 and to the first capacitor 41 on the side opposite to the second capacitor 42. The second converter coil 62 is connected to the second rectifier 32 on the side opposite to the first rectifier 31 and to the second capacitor 42 on the side opposite to the first capacitor 41.

[0047] An impedance conversion circuit is configured by the first capacitor 41, the second capacitor 42, the first conversion coil 61, and the second conversion coil 62. This allows the first capacitor 41 and the second capacitor 42 to be used for impedance matching between the AC power supply 15 and the load 20.

[0048] [1-2] Here, in order to balance the current with respect to the ground 18, the three rectifier coils described in Patent Document 1 may have the same inductance. However, due to manufacturing variations in the rectifier coils, the inductance of the rectifier coils varies. The variation in the inductance of the rectifier coils causes differences in the currents flowing through the rectifier coils. This causes the current balance with respect to the ground 18 to be lost, generating noise currents of the same phase. This causes radiation noise.

[0049] Also, for example, assume that the direction of the current from the AC power supply 15 is forward. At this time, as shown in FIG. 7, as described above, a current flows from the AC power supply 15 to the load 20 via the first input terminal 701, the first conversion coil 61, the first rectifier 31, the third coil 53, and the first output terminal 711. The current that flows through the load 20 flows to the AC power supply 15 via the second output terminal 712, the second coil 52, the second conversion coil 62, and the second input terminal 702. Furthermore, a current flows through the first rectifier 31, the third coil 53, the first output terminal 711, the load 20, the second output terminal 712, the first coil 51, and the first rectifier 31. The current flowing through the first coil 51 and the third coil 53 at this time is I1. The current flowing through the second coil 52 and the third coil 53 at this time is I2. In FIG. 7, I1 is indicated by a dashed line. Furthermore, I2 is shown by a dashed double-dashed line.

[0050] Also, assume that the direction of the current from the AC power supply 15 is negative. At this time, as shown in FIG. 8, as described above, a current flows from the AC power supply 15 to the load 20 via the second input terminal 702, the second conversion coil 62, the second rectifier 32, the third coil 53, and the first output terminal 711. The current that flows through the load 20 flows to the AC power supply 15 via the second output terminal 712, the first coil 51, the first conversion coil 61, and the first input terminal 701. Also, a current flows through the second rectifier 32, the third coil 53, the first output terminal 711, the load 20, the second output terminal 712, the second coil 52, and the second rectifier 32. The current flowing through the first coil 51 and the third coil 53 at this time corresponds to I1. Furthermore, the current flowing through the second coil 52 and the third coil 53 at this time corresponds to I2. In FIG. 8, I1 is indicated by a two-dot chain line. Also, I2 is shown by a dashed line.

[0051] Furthermore, the amplitude of the current from the AC power supply 15 is denoted as V. The frequency of the current from the AC power supply 15 is denoted as ω. The electric resistance of the load 20 is denoted as R. The imaginary number is denoted as j.

[0052] In this case, I1 is expressed using V, ω, R, j, the first inductance Lc1, and the third inductance Lc3 as shown in the following relational expression (1). Also, I2 is expressed using V, ω, R, j, the second inductance Lc2, and the third inductance Lc3 as shown in the following relational expression (2).

[0053]

number

[0054] Here, for example, ω is assumed to be 1 MHz, V is assumed to be 1000 V, and R is assumed to be 5 Ω.

[0055] In this case, it is assumed that there is no variation in the first coil 51, the second coil 52, and the third coil 53, and Lc1 = Lc2 = Lc3 = 10 μH. In this case, |I1| = |I2| = 7.95 A. Since |I1| is equal to |I2|, the current balance with respect to the ground 18 is achieved.

[0056] However, due to manufacturing variations of the first coil 51, the second coil 52, and the third coil 53, the first inductance Lc1, the second inductance Lc2, and the third inductance Lc3 vary. For example, assume that the degree of variation in inductance is ±25%, and Lc1=12.5 μH, Lc2=7.5 μH, and Lc3=10 μH. In this case, |I1|=7.07 A. Also, |I2|=9.09 A. Therefore, |I1|-|I2|=2.02 A. Due to this difference between I1 and I2, the current balance with respect to the ground 18 is lost, and noise currents of the same phase are generated. This causes radiation noise.

[0057] In contrast to this, in the AC / DC converter 30 of this embodiment, the third inductance Lc3 is larger than the first inductance Lc1 and the second inductance Lc2, that is, Lc3>Lc1 and Lc3>Lc2.

[0058] Here, it is assumed that there is no variation in the first coil 51, the second coil 52, and the third coil 53, and that Lc1=Lc2=5 μH and Lc3=15 μH. In this case, |I1|=|I2|=7.95 A, which is the same as when Lc1=Lc2=Lc3=10 μH as described above.

[0059] Then, for example, the degree of variation in inductance is ±25% due to manufacturing variations of the first coil 51, the second coil 52, and the third coil 53, and Lc1=6.25 μH, Lc2=3.75 μH, and Lc3=15 μH. In this case, |I1|=7.48 A. Also, |I2|=8.48 A. Therefore, |I1|-|I2|=1.00 A. Therefore, the absolute value of the difference between I1 and I2 is smaller than that in the case where Lc1=Lc2=Lc3. Therefore, the current balance with respect to the ground 18 is suppressed from being disrupted. Therefore, the generation of noise currents of the same phase is suppressed. Therefore, the generation of radiation noise is suppressed. Also, it is not necessary to connect the third coil 53 to the housing 70. Therefore, the increase in radiation noise is suppressed regardless of the structure of the housing 70.

[0060] Second embodiment 9, the ACDC converter 30 includes a conversion circuit 75 and a filter coil 80 instead of the first conversion coil 61 and the second conversion coil 62. The rest is the same as in the first embodiment.

[0061] The conversion circuit 75 is an impedance conversion circuit, and has a coil, a capacitor, etc., to perform impedance matching between the AC power supply 15 and the load 20. The conversion circuit 75 is connected to a first input terminal 701 and a second input terminal 702. The conversion circuit 75 is also connected to the anode of the first rectifier 31, one end of the first capacitor 41, and one end of the first coil 51. The conversion circuit 75 is also connected to the anode of the second rectifier 32, the other end of the second capacitor 42, and one end of the second coil 52.

[0062] The filter coil 80 is connected to the side of the first capacitor 41 opposite to the second capacitor 42, that is, one end of the first capacitor 41. Furthermore, the filter coil 80 is connected to the side of the second capacitor 42 opposite to the first capacitor 41, that is, the other end of the second capacitor 42. Thus, the filter coil 80 is connected in parallel with the first capacitor 41 and the second capacitor 42.

[0063] The AC / DC converter 30 of the second embodiment is configured as described above. The second embodiment also provides the same effects as the first embodiment. The second embodiment also provides the following effects.

[0064] [2] The first capacitor 41 and the second capacitor 42 can also be used as a filter that makes it easier for noise currents from the first rectifier 31 and the second rectifier 32 to pass through the first capacitor 41 and the second capacitor 42 by using the filter coil 80.

[0065] Third embodiment 10, the third embodiment differs from the second embodiment in the configurations of a first capacitor 41, a second capacitor 42, a conversion circuit 75, and a filter coil 80. The rest is the same as the second embodiment.

[0066] Specifically, the first input terminal 701 is connected to the conversion circuit 75, and is also connected to one end of the first capacitor 41 and one end of the filter coil 80. The second input terminal 702 is connected to the conversion circuit 75, and is also connected to the other end of the second capacitor 42 and the other end of the filter coil 80.

[0067] As described above, the AC / DC converter 30 of the third embodiment is configured. The third embodiment also provides the same effects as the second embodiment.

[0068] (Fourth embodiment) In the fourth embodiment, as shown in FIG. 11, the ACDC converter 30 does not include a bypass path 55. Moreover, the ACDC converter 30 does not include a third capacitor 43 and a fourth capacitor 44. Moreover, the aspects of the first capacitor 41 and the second capacitor 42 are different from those of the first embodiment. Specifically, the first capacitor 41 is connected in parallel with the first rectifier 31 and the second rectifier 32. Moreover, one end of the first capacitor 41 is connected to the side of the first rectifier 31 opposite to the second rectifier 32, here, the anode of the first rectifier 31. Moreover, the other end of the first capacitor 41 is connected to the side of the second rectifier 32 opposite to the first rectifier 31, here, the anode of the second rectifier 32. The second capacitor 42 is connected in parallel with the load 20. Moreover, one end of the second capacitor 42 is connected to the third coil 53. Moreover, one end of the second capacitor 42 is connected to one end of the load 20 via the first output terminal 711. The other end of the second capacitor 42 is connected to the other end of the first coil 51 and the other end of the second coil 52. Furthermore, the other end of the second capacitor 42 is connected to the other end of the load 20 via the second output terminal 712. Other than these, the fourth embodiment is similar to the first embodiment. The fourth embodiment also provides the same effects as those described in [1-2] above.

[0069] (Other embodiments) The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, in each of the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are particularly clearly stated as essential or where they are clearly considered essential in principle.

[0070] The above embodiments may be combined as appropriate. [Explanation of symbols]

[0071] 31 1st rectifier 32 Second rectifier 41 First capacitor 42 Second Capacitor 43 Third Capacitor 44 4th Capacitor 51 First coil 52 Second coil 55 Bypass Route 70 Case

Claims

1. a first rectifier (31) that outputs a positive portion of an AC current from an AC power source (15) to a load (20); a second rectifier (32) that converts the AC current to a DC current together with the first rectifier by outputting a negative portion of the AC current to the load; a first capacitor (41) connected in parallel with the first rectifier and the second rectifier and connected to the first rectifier on the opposite side to the second rectifier; a second capacitor (42) connected in series with the first capacitor and connected to the second rectifier on the opposite side to the first rectifier; a third capacitor (43) connected in parallel with the load and between the first rectifier and the second rectifier; a fourth capacitor (44) connected in series with the third capacitor and connected to the load on the opposite side to the third capacitor; a first coil (51) connected to the first rectifier on the opposite side to the second rectifier and smoothing the output from the second rectifier together with the third capacitor and the fourth capacitor; a second coil (52) connected to the second rectifier on the opposite side to the first rectifier and smoothing the output from the first rectifier together with the third capacitor and the fourth capacitor; a bypass path (55) connected between the first capacitor and the second capacitor and between the third capacitor and the fourth capacitor; a housing (70) that houses the first rectifier, the second rectifier, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the first coil, the second coil, and the bypass path; An AC-DC converter comprising:

2. a first conversion coil (61) connected to a side of the first rectifier opposite to the second rectifier and to a side of the first capacitor opposite to the second capacitor; a second conversion coil (62) connected to the second rectifier on the opposite side to the first rectifier and to the second capacitor on the opposite side to the first capacitor; The AC-DC converter according to claim 1 .

3. 2. The AC-DC converter of claim 1, further comprising a filter coil (80) connected in parallel with the first capacitor and the second capacitor.

4. The ACDC converter further includes a third coil (53) connected between the first rectifier and the second rectifier and to the third capacitor; 4. The AC-DC converter according to claim 1, wherein an inductance (Lc3) of the third coil is greater than an inductance (Lc1) of the first coil and an inductance (Lc2) of the second coil.

5. 4. The ACDC converter according to claim 1, wherein an impedance of the bypass path is lower than an impedance of a current path passing from the first rectifier and the second rectifier to the ground.

6. An AC-DC converter, a first rectifier (31) that outputs a positive portion of an AC current from an AC power source (15) to a load (20); a second rectifier (32) that converts the AC current to a DC current together with the first rectifier by outputting a negative portion of the AC current to the load; a capacitor connected in parallel with the load and between the first rectifier and the second rectifier; a first coil (51) connected to the first rectifier on the opposite side to the second rectifier and smoothing the output from the second rectifier together with the capacitor; a second coil (52) connected to the second rectifier on the opposite side to the first rectifier and smoothing the output from the first rectifier together with the capacitor; a third coil (53) connected between the first rectifier and the second rectifier and to the capacitor; a housing (70) that houses the first rectifier, the second rectifier, the capacitor, the first coil, the second coil, and the third coil; Equipped with An AC-DC converter, wherein an inductance (Lc3) of the third coil is larger than an inductance (Lc1) of the first coil and an inductance (Lc2) of the second coil.

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