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] This disclosure relates to an AC-DC converter.

Background Art

[0002] Conventionally, as described in Patent Document 1, a wireless power feeding device including a rectifier circuit section having three rectifier coils and two diodes is known. This rectifier circuit section converts high-frequency power from a high-frequency power supply section into direct current by rectification. The power rectified 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

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the rectifier circuit described in Patent Document 1, rectification by the diode causes noise currents with the same phase to flow from the diode to the positive and negative sides of the high-frequency power supply in the same direction, and return to the diode via the ground. At this time, since the path of the noise current is in the same direction, relatively large radiated noise is generated. Therefore, in order to reduce the noise current and radiated noise, the rectifier circuit is sometimes housed in a metal enclosure, and a Y-capacitor is provided connected to the input and output terminals of the rectifier circuit and the metal enclosure. When this Y-capacitor is provided, a portion of the noise current from the diode passes through the Y-capacitor, reducing the noise current that passes from the diode to the ground. This reduces radiated noise. However, depending on the structure of the metal enclosure, the distance between the metal enclosure and the Y-capacitor may be long, which increases the impedance in the path of the noise current that passes from the diode to the Y-capacitor. When the impedance in this path is high, the noise current that passes from the diode to the Y-capacitor is reduced. As a result, the noise current that passes from the diode to the ground increases. Therefore, even if a Y-capacitor is provided, radiated noise may increase depending on the structure of the metal enclosure.

[0005] This disclosure aims to provide an AC / DC converter that suppresses the increase in radiated noise regardless of the enclosure structure. [Means for solving the problem]

[0006] The invention described in claim 1 includes: a first rectifier (31) that outputs the positive portion of the alternating current from an AC power source (15) to a load (20); a second rectifier (32) that converts the alternating current to a direct current together with the first rectifier by outputting the negative portion of the alternating current to the load; a first capacitor (41) connected in parallel with the first and second rectifiers and connected to the first rectifier on the opposite side from the second rectifier; a second capacitor (42) connected in series with the first capacitor and connected to the second rectifier on the opposite side from the first rectifier; a third capacitor (43) connected in parallel with the load and connected between the first and second rectifiers; and a third capacitor connected in series with the third capacitor and on the opposite side from the third capacitor of the load. The AC / DC converter comprises a fourth capacitor (44) connected to the first rectifier, a first coil (51) connected to the first rectifier on the opposite side from the second rectifier and smoothing the output from the second rectifier together with the third and fourth capacitors, a second coil (52) connected to the second rectifier on the opposite side from the first rectifier and smoothing the output from the first rectifier together with the third and fourth capacitors, a bypass path (55) connected between the first and second capacitors and between the third and fourth capacitors, and a housing (70) that accommodates 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 a single current path housed within the enclosure, its impedance is lower than that of the noise current path from the first and second rectifiers to the ground. Therefore, noise current from the first and second rectifiers easily flows into the bypass path via the first or second capacitor. Furthermore, the noise current flowing through the bypass path passes through the third or fourth capacitor. Consequently, because noise current from the first and second rectifiers flows into the bypass path, the noise current from the first and second rectifiers to the ground is reduced. This suppresses the increase in radiated noise. Moreover, there is no need to connect the bypass path to the enclosure. Therefore, the increase in radiated noise is suppressed regardless of the enclosure structure.

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

[0009] As a result, compared to the case where the inductances of the first, second, and third coils are the same, the difference between the currents flowing through the first and third coils and the currents flowing through the second and third coils when the AC current is converted to DC current is reduced. Therefore, the disruption of the current balance with respect to the ground is suppressed. Consequently, the generation of noise current is suppressed. Consequently, the generation of radiated noise is suppressed. In addition, it is not necessary to connect the third coil to the enclosure. Therefore, the increase in radiated noise is suppressed regardless of the structure of the enclosure.

[0010] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0011] [Figure 1] A diagram illustrating the configuration of a power conversion system using the AC / DC converter of the first embodiment. [Figure 2] This diagram shows the current flow when an AC / DC converter converts alternating current to direct current. [Figure 3] This diagram shows the current flow when an AC / DC converter converts alternating current to direct current. [Figure 4] A diagram showing the noise current flow in the comparative example. [Figure 5] This diagram shows the noise current flowing through the bypass path of an AC / DC converter. [Figure 6] This diagram shows 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] This diagram shows the current flow when an AC / DC converter converts alternating current to direct current. [Figure 8] This diagram shows the current flow when an AC / DC converter converts alternating current to direct current. [Figure 9] A diagram illustrating the configuration of a power conversion system using the AC / DC converter of the second embodiment. [Figure 10]Configuration diagram of a power conversion system in which the AC-DC converter of the third embodiment is used. [Figure 11] Configuration diagram of a power conversion system in which the AC-DC converter of the fourth embodiment is used.

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, parts that are identical or equivalent to each other 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, an increase in radiated noise is suppressed regardless of the structure of the housing. The AC-DC converter is used in a power conversion system that converts an alternating current into a direct current. First, this power conversion system will be described.

[0014] As shown in FIG. 1, the power conversion system 10 includes an AC power supply 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 alternating current. The AC power supply 15 is connected to the ground 18 via a parasitic capacitor 17. The load 20 is, for example, a power storage device or the like. Further, the load 20 is connected to the ground 18 via a parasitic capacitor 17.

[0016] The AC-DC 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 AC-DC 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 the positive part of the alternating 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. Further, the second rectifier 32 outputs the negative part of the alternating current from the AC power supply 15 to the load 20. Thereby, the second rectifier 32, together with the first rectifier 31, converts the alternating current from the AC power supply 15 into a direct current.

[0018] The first capacitor 41 is connected in parallel with 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, here, to the anode of the first rectifier 31. [[ID=⑤]] [[ID=⑥]]

[0019] [[ID=⑦]] [[ID=⑧]]The second capacitor 42 is connected in parallel with the first rectifier 31 and the second rectifier 32 together with the first capacitor 41. Further, one end of the second capacitor 42 is connected in series with the other end of the first capacitor 41. Also, 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. [[ID=⑨]] [[ID=⑩]]

[0020] [[ID=⑪]] [[ID=⑫]]The third capacitor 43 is connected in parallel with the load 20. Further, 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. Also, one end of the third capacitor 43 is connected to one end of the load 20 via the first output terminal 711 of the housing 70 described later. [[ID=⑬]] [[ID=⑭]]

[0021] [[ID=⑮]] [[ID=⑯]]The fourth capacitor 44 is connected in parallel with the load 20 together with the third capacitor 43. Further, one end of the fourth capacitor

[0022] 44 is connected in series with the other end of the third capacitor 43. Also, the other end of the fourth capacitor 44 is connected to the other end of the load 20 via the second output terminal 712 of the housing 70 described later. [[ID=⑰]] [[ID=⑱]]

[0022] [[ID=⑲]] 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, together with the third capacitor 43 and the fourth capacitor 44, forms an LC circuit. As a result, the first coil 51, together with the third capacitor 43 and the fourth capacitor 44, smooths the output from the second rectifier 32, as will be described later.

[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. The second coil 52 also forms an LC circuit with the third capacitor 43 and the fourth capacitor 44. As a result, the second coil 52, together with the third capacitor 43 and the fourth capacitor 44, smooths the output from the first rectifier 31, as will be described later.

[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, together with the third capacitor 43, the fourth capacitor 44, the first coil 51, and the second coil 52, constitute an LC circuit. As a result, the third coil 53 smooths the outputs from the first rectifier 31 and the second rectifier 32, as will be described later.

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

[0026] Furthermore, the third inductance Lc3 is greater than the first inductance Lc1 and the second inductance Lc2, i.e., Lc3 > Lc1 and Lc3 > Lc2. Note that the first inductance Lc1 and the second inductance Lc2 may be the same or different. That is, Lc1 = Lc2 may be, and Lc1 ≠ Lc2.

[0027] The bypass path 55 consists of wiring, etc. One end of the bypass path 55 is connected between the first capacitor 41 and the second capacitor 42, specifically the other end of the first capacitor 41 and one end of the second capacitor 42. Furthermore, the other end of the bypass path 55 is connected between the third capacitor 43 and the fourth capacitor 44, specifically the other end of the third capacitor 43 and one end of the fourth capacitor 44.

[0028] One end of the first conversion coil 61 is connected to the anode of the first rectifier 31, on the side opposite to the second rectifier 32. Also, one end of the first conversion coil 61 is connected to the end of the first capacitor 41, on the side opposite to the second capacitor 42. 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 conversion coil 62 is connected to the anode of the second rectifier 32, on the side opposite to the first rectifier 31. Furthermore, one end of the second conversion coil 62 is connected to the other end of the second capacitor 42, on the side opposite to the first capacitor 41. In addition, one end of the second conversion coil 62 is connected to one end of the second coil 52. The second conversion coil 62, together with the first capacitor 41, the second capacitor 42, and the first conversion coil 61, constitutes an impedance matching circuit. This impedance matching circuit 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. Furthermore, the housing 70 houses the first coil 51, the second coil 52, the third coil 53, the bypass path 55, the first conversion coil 61, and the second conversion 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 equipped with the AC / DC converter 30 of the first embodiment is configured as described. Next, the conversion from alternating current to direct current by the AC / DC converter 30 will be explained.

[0036] Here, the direction of the current flowing from the AC power supply 15 to the first input terminal 701 is defined as the positive direction. Also, the direction of the current flowing from the AC power supply 15 to the second input terminal 702 is defined as the 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 composed of a first capacitor 41, a second capacitor 42, a first conversion coil 61, and a second conversion coil 62. This impedance conversion circuit performs impedance matching between the AC power supply 15 and the load 20.

[0038] Furthermore, when the direction of the current from the AC power supply 15 is positive, as shown in Figure 2, current flows from the AC power supply 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 the positive portion of the AC current from the AC power supply 15 to the load 20, and therefore outputs current to the load 20 via the third coil 53 and the first output terminal 711. Furthermore, the current that flows through the load 20 flows back 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. At this time, the current flowing through the load 20 is smoothed by the LC circuit composed of the second coil 52, the third coil 53, the third capacitor 43, and the fourth capacitor 44. Note that in Figure 2, the flow of current is shown by a dashed line.

[0039] Furthermore, if the direction of the current from the AC power supply 15 is negative, as shown in Figure 3, current flows from the AC power supply 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 portion of the AC current from the AC power supply 15 to the load 20, and therefore outputs current to the load 20 via the third coil 53 and the first output terminal 711. In this way, the second rectifier 32, together with the first rectifier 31, converts the AC current from the AC power supply 15 to DC current. Furthermore, the current that flows to the load 20 flows back 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. At this time, the current flowing to the load 20 is smoothed by the LC circuit composed of the first coil 51, the third coil 53, the third capacitor 43, and the fourth capacitor 44. In Figure 3, the flow of current is shown by a dashed line.

[0040] As described above, the AC / DC converter 30 converts alternating current to direct current. Next, we will explain how the AC / DC converter 30 suppresses the increase in radiated noise, regardless of the structure of the enclosure 70.

[0041] Here, as shown in the comparative AC / DC converter 90 in Figure 4, multiple Y capacitors 100 may be provided. The Y capacitors 100 are connected to the enclosure 70. The Y capacitors 100 are 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 enclosure 70, the distance between the enclosure 70 and the Y capacitors 100 may be long, resulting in a higher impedance in the path of noise current passing from the first rectifier 31 and the second rectifier 32 through the Y capacitors 100. A high impedance in this path reduces the noise current passing from the first rectifier 31 and the second rectifier 32 through the Y capacitors 100. As a result, the noise current passing from the first rectifier 31 and the second rectifier 32 through the ground 18 increases. Therefore, even with the provision of Y capacitors 100, radiated noise may increase depending on the structure of the enclosure 70. In Figure 4, the noise currents passing from the first rectifier 31 and the second rectifier 32 through the Y capacitor 100 are shown by dashed lines. Additionally, the noise currents passing from the first rectifier 31 and the second rectifier 32 through the ground 18 are shown by dashed lines.

[0042] In contrast, the AC / DC converter 30 of this embodiment is equipped with a bypass path 55, as shown in Figure 1. 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 a single current path housed within the enclosure 70, the impedance of the bypass path 55 is lower than the impedance of the noise current path from the first rectifier 31 and the second rectifier 32 through the ground 18. Therefore, as shown in Figure 5, the noise current from the first rectifier 31 and the second rectifier 32 easily flows into the bypass path 55 via the first capacitor 41 or the second capacitor 42. Furthermore, the noise current that flows through the bypass path 55 passes through the third capacitor 43 or the fourth capacitor 44. In Figure 5, the noise current from the first rectifier 31 and the second rectifier 32 through the bypass path 55 is shown by a dashed line. In addition, the noise current from the first rectifier 31 and the second rectifier 32 through the ground 18 is shown by a broken 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 from the first rectifier 31 and the second rectifier 32 through the ground 18 is reduced, as shown in Figure 6. This suppresses the increase in radiated noise. Furthermore, it is not necessary to connect the bypass path 55 to the enclosure 70. Thus, the increase in radiated noise is suppressed regardless of the structure of the enclosure 70.

[0045] Furthermore, the ACDC converter 30 of the first embodiment also provides the following effects.

[0046] [1-1] As shown in Figure 1, the AC / DC converter 30 includes a first conversion coil 61 and a second conversion coil 62. The first conversion coil 61 is connected to the side of the first rectifier 31 opposite to the second rectifier 32 and to the side of the first capacitor 41 opposite to the second capacitor 42. The second conversion coil 62 is connected to the side of the second rectifier 32 opposite to the first rectifier 31 and to the side of the second capacitor 42 opposite to the first capacitor 41.

[0047] The first capacitor 41, the second capacitor 42, the first conversion coil 61, and the second conversion coil 62 constitute an impedance conversion circuit. 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] In order to balance the current with respect to the earth 18, the inductances of the three rectifier coils described in Patent Document 1 are sometimes made the same. However, due to variations in the manufacturing of the rectifier coils, the inductance of the rectifier coils varies. This variation in the inductance of the rectifier coils causes differences in the current flowing through the rectifier coils. As a result, the current balance with respect to the earth 18 is disrupted, and in-phase noise currents are generated. This results in radiated noise.

[0049] Furthermore, let us assume, for example, that the direction of the current from the AC power supply 15 is positive. In this case, as shown in Figure 7, as described above, 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 flowing through the load 20 flows back 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. In addition, 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 denoted as I1. The current flowing through the second coil 52 and the third coil 53 at this time is denoted as I2. Note that in Figure 7, I1 is shown by a dashed line. Furthermore, I2 is indicated by a dashed line.

[0050] Furthermore, assume that the direction of the current from the AC power supply 15 is negative. In this case, as shown in Figure 8, as described above, 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 flowing through the load 20 flows back 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. Current also 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 currents flowing through the first coil 51 and the third coil 53 at this time correspond to I1. Furthermore, the currents flowing through the second coil 52 and the third coil 53 at this time correspond to I2. Note that in Figure 8, I1 is shown by a dashed line. Furthermore, I2 is indicated by a dashed line.

[0051] Furthermore, let V be the amplitude of the current from AC power supply 15. Let ω be the frequency of the current from AC power supply 15. Let R be the electrical resistance of load 20. Let j be the imaginary number.

[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 relation (1). Similarly, I2 is expressed using V, ω, R, j, the second inductance Lc2, and the third inductance Lc3, as shown in the following relation (2).

[0053]

number

[0054] Furthermore, let's assume, for example, that ω is 1 MHz, V is 1000 V, and R is 5 Ω.

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

[0056] However, due to manufacturing variations in the first coil 51, second coil 52, and third coil 53, the first inductance Lc1, second inductance Lc2, and third inductance Lc3 will vary. For example, let's assume the 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 disrupted, resulting in the generation of in-phase noise current. This generates radiated noise.

[0057] In contrast, 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, we assume 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 the case above where Lc1 = Lc2 = Lc3 = 10 μH.

[0059] Furthermore, due to manufacturing variations in the first coil 51, the second coil 52, and the third coil 53, for example, let's assume that the degree of variation in inductance is ±25%, and that 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. Thus, the absolute value of the difference between I1 and I2 is smaller compared to the case where Lc1 = Lc2 = Lc3. As a result, the disruption of the current balance with respect to the ground 18 is suppressed. Therefore, the generation of in-phase noise current is suppressed. Therefore, the generation of radiated noise is suppressed. In addition, it is not necessary to connect the third coil 53 to the housing 70. Therefore, the increase in radiated noise is suppressed regardless of the structure of the housing 70.

[0060] (Second Embodiment) In the second embodiment, as shown in Figure 9, the AC / DC 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. Otherwise, it is the same as in the first embodiment.

[0061] The conversion circuit 75 is an impedance conversion circuit that performs impedance matching between the AC power supply 15 and the load 20 by having a coil and a capacitor, etc. The conversion circuit 75 is connected to the first input terminal 701 and the second input terminal 702. Furthermore, the conversion circuit 75 is connected to the anode of the first rectifier 31, one end of the first capacitor 41, and one end of the first coil 51. Also, the conversion circuit 75 is 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 one end of the first capacitor 41, on the side opposite to the second capacitor 42. Furthermore, the filter coil 80 is connected to the other end of the second capacitor 42, on the side opposite to the first capacitor 41. Therefore, the filter coil 80 is connected in parallel with both the first capacitor 41 and the second capacitor 42.

[0063] As described above, the AC / DC converter 30 of the second embodiment is configured as described. This second embodiment also provides the same effects as the first embodiment. Furthermore, the second embodiment also provides the effects described below.

[0064] [2] The filter coil 80 can be used to make 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, and the first capacitor 41 and the second capacitor 42 can also be used as filters.

[0065] (Third embodiment) In the third embodiment, as shown in Figure 10, the configurations of the first capacitor 41, the second capacitor 42, the conversion circuit 75, and the filter coil 80 differ from those of the second embodiment. Otherwise, it is the same as the second embodiment.

[0066] Specifically, the first input terminal 701 is connected to the conversion circuit 75, as well as to one end of the first capacitor 41 and one end of the filter coil 80. The second input terminal 702 is also connected to the conversion circuit 75, as well as 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 as described above. This third embodiment also provides the same effects as the second embodiment.

[0068] (Fourth Embodiment) In the fourth embodiment, as shown in Figure 11, the ACDC converter 30 does not have a bypass path 55. Also, the ACDC converter 30 does not have a third capacitor 43 and a fourth capacitor 44. Furthermore, the configuration of the first capacitor 41 and the second capacitor 42 differs from that of the first embodiment. Specifically, the first capacitor 41 is connected in parallel with the first rectifier 31 and the second rectifier 32. One end of the first capacitor 41 is connected to the anode of the first rectifier 31, on the side of the first rectifier 31 opposite to the second rectifier 32. The other end of the first capacitor 41 is connected to the anode of the second rectifier 32, on the side of the second rectifier 32 opposite to the first rectifier 31. The second capacitor 42 is connected in parallel with the load 20. One end of the second capacitor 42 is connected to the third coil 53. Furthermore, one end of the second capacitor 42 is connected to one end of the load 20 via the first output terminal 711. Furthermore, 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. In addition, the other end of the second capacitor 42 is connected to the other end of the load 20 via the second output terminal 712. Except for these, it is the same as the first embodiment. This fourth embodiment also produces the same effects as those described in [1-2] above.

[0069] (Other embodiments) This disclosure is not limited to the embodiments described above, and modifications can be made to these embodiments as appropriate. Furthermore, it goes without saying that, in each of the embodiments described above, the elements constituting the embodiment are not necessarily essential, except in cases where they are explicitly stated to be particularly 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. Fourth Capacitor 51. First coil 52 Second coil 55 Bypass Route 70 cabinets

Claims

1. A first rectifier (31) outputs the positive portion of the AC current from the AC power source (15) to the load (20), A second rectifier (32) that converts the alternating current into a direct current together with the first rectifier by outputting the negative portion of the alternating current to the load, A first capacitor (41) is connected in parallel with the first rectifier and the second rectifier, and is connected to the first rectifier on the opposite side from the second rectifier, A second capacitor (42) is connected in series with the first capacitor and is connected to the second rectifier on the opposite side from the first rectifier, A third capacitor (43) is connected in parallel with the load and also connected between the first rectifier and the second rectifier, A fourth capacitor (44) is connected in series with the third capacitor and is connected to the load on the opposite side from the third capacitor, A first coil (51) is connected to the opposite side of the first rectifier from the second rectifier, and smooths the output from the second rectifier together with the third capacitor and the fourth capacitor. A second coil (52) is connected to the second rectifier on the opposite side from the first rectifier, and smooths the output from the first rectifier together with the third capacitor and the fourth capacitor, A bypass path (55) is connected between the first capacitor and the second capacitor, and between the third capacitor and the fourth capacitor, A housing (70) housing 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, A DC converter equipped with [specific features / features].

2. A first conversion coil (61) is connected to the side of the first rectifier opposite to the second rectifier, and to the side of the first capacitor opposite to the second capacitor, A second conversion coil (62) is connected to the side of the second rectifier opposite to the first rectifier, and to the side of the second capacitor opposite to the first capacitor, The ADC converter according to claim 1, comprising:

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

4. The AC / DC converter further comprises a third coil (53) connected between the first rectifier and the second rectifier and the third capacitor, The ADC converter according to any one of claims 1 to 3, wherein the inductance of the third coil (Lc3) is greater than the inductance of the first coil (Lc1) and the inductance of the second coil (Lc2).

5. The ADC converter according to any one of claims 1 to 3, wherein the impedance of the bypass path is lower than the impedance of the current path from the first rectifier and the second rectifier through to the ground.

6. It is an ADC converter, A first rectifier (31) outputs the positive portion of the AC current from the AC power source (15) to the load (20), A second rectifier (32) that converts the alternating current into a direct current together with the first rectifier by outputting the negative portion of the alternating current to the load, A capacitor connected in parallel with the load and connected between the first rectifier and the second rectifier, A first coil (51) is connected to the first rectifier on the opposite side from the second rectifier, and together with the capacitor, smooths the output from the second rectifier. A second coil (52) is connected to the second rectifier on the opposite side from the first rectifier and smooths the output from the first rectifier together with the capacitor, A third coil (53) is connected between the first rectifier and the second rectifier, and to the capacitor, A housing (70) housing the first rectifier, the second rectifier, the capacitor, the first coil, the second coil, and the third coil, Equipped with, An ADC converter in which the inductance of the third coil (Lc3) is greater than the inductance of the first coil (Lc1) and the inductance of the second coil (Lc2).

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