Power Conversion Equipment

Abstract

To solve such a problem that noise is generated due to switching of each switching element in a power conversion device.SOLUTION: A power conversion device 10 includes a metal housing 20, a plurality of power conversion circuits 30, and a control unit controlling each power conversion circuit. Each power conversion circuit 30 includes a high potential input terminal and a low potential input terminal, an output terminal 23, an input capacitor, an inductor, a switching element, and a first common mode choke coil. The first common mode choke coil includes a magnetic core. The first common mode choke coils of two or more of the power conversion circuits 30 share the same magnetic core. The control unit controls on / off of each switching element in each power conversion circuit 30 such that the timing of on / off of each switching element is deviated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] Patent Document 1 discloses a power conversion device. This power conversion device includes a battery and two output circuits. Power from the battery is supplied to each output circuit via a transformer. Each output circuit includes a common mode choke coil. This common mode choke coil has a core and a wiring wound around the core. The common mode choke coils of the two output circuits share the same core. This makes the impedance characteristics of the common mode choke coils for each output circuit uniform. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 61-111220 Summary of the Invention [Problem to be solved by the invention]

[0004] In many cases, the output circuit of the power conversion device described in Patent Document 1 is mounted inside a metal case. In this case, parasitic capacitance may occur between each wiring of the output circuit and the metal case. When the switching element of the power conversion device is switched, noise in the power conversion device as a whole becomes non-negligible. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a power conversion circuit comprising a metal casing, a plurality of power conversion circuits built into the metal casing, and a control unit that controls each of the power conversion circuits, wherein each of the power conversion circuits has a high potential input terminal and a low potential input terminal, an output terminal, a first terminal and a second terminal, the first terminal being connected to the high potential input terminal, an input capacitor having the second terminal connected to the low potential input terminal, an inductor having a third terminal and a fourth terminal, the third terminal being connected to the high potential input terminal, and a fifth terminal, a sixth terminal and a seventh terminal, the fifth terminal being connected to the fourth terminal of the inductor, the sixth terminal being connected to the second terminal of the input capacitor, and a signal from the control unit being input to the seventh terminal. a switching element to which a voltage is input; and a first common mode choke coil having an eighth terminal, a ninth terminal, a tenth terminal, and an eleventh terminal, the eighth terminal connected to the high potential input terminal, the ninth terminal connected to the first terminal of the input capacitor, the ninth terminal connected to the low potential input terminal, and the eleventh terminal connected to the second terminal of the input capacitor, wherein the first common mode choke coil has a magnetic core, each of the first common mode choke coils of two or more of the power conversion circuits share the same magnetic core, and the control unit controls the on and off of each of the switching elements of each of the power conversion circuits so that the on and off timing of each of the switching elements is staggered.

[0006] According to the above configuration, each common mode choke coil of the multiple power conversion circuits is connected to a high potential input terminal and a low potential input terminal. This makes it possible to reduce the parasitic capacitance formed between the wiring near each input terminal and the metal housing. Therefore, noise caused by the current flowing through this parasitic capacitance can be efficiently suppressed.

[0007] On the other hand, the on and off timing of each switching element is shifted. Therefore, the on and off timing of the switching elements of each power conversion circuit does not match. Therefore, the current peaks caused by the switching operation of the on and off control of each switching element do not overlap, so large noise can be suppressed. Effect of the Invention

[0008] Noise caused by the switching of each switching element can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a circuit diagram of a power conversion device. [Diagram 2] FIG. 2 is a diagram of a first common mode choke coil. [Diagram 3] FIG. 11 is a circuit diagram of a power conversion device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <One embodiment of a power conversion device> Hereinafter, an embodiment of a power conversion device will be described with reference to the drawings. Note that the drawings may show components enlarged for ease of understanding. The dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0011] (Configuration of power conversion device) First, the circuit configuration of the power conversion device 10 will be described. As shown in FIG. 1, the power conversion device 10 includes a metal housing 20 , a plurality of power conversion circuits 30 , a control and drive circuit 50 , and an inverter 60 .

[0012] The metal housing 20 has a box shape with a space inside. The material of the metal housing 20 is a conductive metal. The metal housing 20 has a ground terminal 24. The ground terminal 24 is connected to the metal housing 20 inside the metal housing 20. The ground terminal 24 is also grounded outside the metal housing 20.

[0013] The power conversion device 10 includes a first power conversion circuit 30A and a second power conversion circuit 30B. The first power conversion circuit 30A has a first high potential input terminal 31Aa, a first low potential input terminal 31Ab, and two output terminals 23. The first high potential input terminal 31Aa, the first low potential input terminal 31Ab, and the two output terminals 23 are attached to a metal housing 20.

[0014] The first high potential input terminal 31Aa is connected to a high potential terminal of the first DC power supply 80A. The first low potential input terminal 31Ab is connected to a low potential terminal of the first DC power supply 80A. The first DC power supply 80A is installed outside the metal casing 20. The first DC power supply 80A is, for example, a solar power generation panel.

[0015] Each output terminal 23 is connected to a power system 91 via a power line 90 extending from each output terminal 23 to the outside of the metal housing 20. The power line 90 includes electrical equipment (not shown) such as a distribution board, a watt-hour meter, and a socket (outlet). The power line 90 is also connected to a load circuit 92. The load circuit 92 is an electrical device that operates using AC power from the power line 90. The load circuit 92 is, for example, a lighting fixture, a television, a refrigerator, a washing machine, an air conditioner, a microwave oven, an air purifier, etc.

[0016] The first power conversion circuit 30A includes a first input capacitor 32A. The first input capacitor 32A has a first terminal 32Aa and a second terminal 32Ab. The first terminal 32Aa of the first input capacitor 32A is connected to the first high potential input terminal 31Aa. The second terminal 32Ab of the first input capacitor 32A is connected to the first low potential input terminal 31Ab. The first power conversion circuit 30A also includes a first inductor 33A. The first inductor 33A has a third terminal 33Aa and a fourth terminal 33Ab. The third terminal 33Aa of the first inductor 33A is connected to the first high potential input terminal 31Aa.

[0017] The first power conversion circuit 30A includes a first rectifier element 34A. The first rectifier element 34A has an 18th terminal 34Aa and a 19th terminal 34Ab. The 18th terminal 34Aa of the first rectifier element 34A is connected to a fourth terminal 33Ab of the first inductor 33A. The 19th terminal 34Ab of the first rectifier element 34A is connected to the output terminal 23 via the inverter 60. The first rectifier element 34A allows a current to flow from the first inductor 33A side to the output terminal 23 side, but does not allow a current to flow from the output terminal 23 side to the first inductor 33A side.

[0018] The first power conversion circuit 30A includes a first switching element 35A. The first switching element 35A has a fifth terminal 35Aa, a sixth terminal 35Ab, and a seventh terminal 35Ac. The first switching element 35A is an N-channel MOSFET (metal oxide semiconductor field effect transistor). The fifth terminal 35Aa of the first switching element 35A is a drain terminal. The sixth terminal 35Ab of the first switching element 35A is a source terminal. The seventh terminal 35Ac of the first switching element 35A is a gate terminal. The fifth terminal 35Aa of the first switching element 35A is connected to the fourth terminal 33Ab of the first inductor 33A. The sixth terminal 35Ab of the first switching element 35A is connected to the second terminal 32Ab of the first input capacitor 32A. The sixth terminal 35Ab of the first switching element 35A is connected to the output terminal 23 via the inverter 60. The seventh terminal 35Ac of the first switching element 35A is connected to the control / drive circuit 50.

[0019] The first power conversion circuit 30A includes an output capacitor 39. The output capacitor 39 has a 20th terminal 39a and a 21st terminal 39b. The 20th terminal 39a of the output capacitor 39 is connected to the fifth terminal 35Aa of the first switching element 35A via the first rectifier element 34A. The 20th terminal 39a of the output capacitor 39 is connected to one output terminal 23 via the inverter 60. On the other hand, the 21st terminal 39b of the output capacitor 39 is connected to the sixth terminal 35Ab of the first switching element 35A. The 21st terminal 39b of the output capacitor 39 is connected to the other output terminal 23 via the inverter 60. The output capacitor 39 is an aluminum electrolytic capacitor.

[0020] The first power conversion circuit 30A includes a first common mode choke coil and a second common mode choke coil. Hereinafter, in this embodiment, the first common mode choke coil included in the first power conversion circuit 30A is referred to as a "first front-stage common mode choke coil 36A." Also, hereinafter, in this embodiment, the second common mode choke coil included in the first power conversion circuit 30A is referred to as a "first rear-stage common mode choke coil 37A."

[0021] The first front-stage common mode choke coil 36A includes an eighth terminal 36Aa, a ninth terminal 36Ab, a tenth terminal 36Ac, and an eleventh terminal 36Ad. The first front-stage common mode choke coil 36A also includes two coils and a magnetic core 40, which will be described later. The two coils share one magnetic core 40.

[0022] The eighth terminal 36Aa and the ninth terminal 36Ab of the first front-stage common mode choke coil 36A are the same as the two terminals of the other coil. The eighth terminal 36Aa is connected to the first high potential input terminal 31Aa. The ninth terminal 36Ab is connected to the first terminal 32Aa of the first input capacitor 32A via the first rear-stage common mode choke coil 37A.

[0023] The tenth terminal 36Ac and the eleventh terminal 36Ad of the first front-stage common mode choke coil 36A are the same as the two terminals of the other coil. The tenth terminal 36Ac is connected to the first low potential input terminal 31Ab. The eleventh terminal 36Ad is connected to the second terminal 32Ab of the first input capacitor 32A via the first rear-stage common mode choke coil 37A. In this way, the first front-stage common mode choke coil 36A is located between the first high potential input terminal 31Aa and the first terminal 32Aa of the first input capacitor 32A, and between the first low potential input terminal 31Ab and the second terminal 32Ab of the first input capacitor 32A.

[0024] The first rear-stage common mode choke coil 37A includes a twelfth terminal 37Aa, a thirteenth terminal 37Ab, a fourteenth terminal 37Ac, and a fifteenth terminal 37Ad. The first rear-stage common mode choke coil 37A includes two coils and a core that is an annular magnetic body. The two coils share one core.

[0025] The twelfth terminal 37Aa and the thirteenth terminal 37Ab of the first rear-stage common mode choke coil 37A are the same as the two terminals of the other coil. The twelfth terminal 37Aa is connected to the ninth terminal 36Ab of the first front-stage common mode choke coil 36A. The thirteenth terminal 37Ab is connected to the first terminal 32Aa of the first input capacitor 32A.

[0026] The 14th terminal 37Ac and the 15th terminal 37Ad of the first rear stage common mode choke coil 37A are the same as the two terminals of the other coil. The 14th terminal 37Ac is connected to the 11th terminal 36Ad of the first front stage common mode choke coil 36A. The 15th terminal 37Ad is connected to the second terminal 32Ab of the first input capacitor 32A. In this way, the first rear stage common mode choke coil 37A is located between the first front stage common mode choke coil 36A and the first terminal 32Aa of the first input capacitor 32A, and between the first front stage common mode choke coil 36A and the second terminal 32Ab of the first input capacitor 32A. The inductance of the first front stage common mode choke coil 36A is smaller than the inductance of the first rear stage common mode choke coil 37A.

[0027] The first power conversion circuit 30A includes a first capacitor 38A. The first capacitor 38A has a sixteenth terminal 38Aa and a seventeenth terminal 38Ab. The sixteenth terminal 38Aa of the first capacitor 38A is connected to a wiring between a ninth terminal 36Ab of the first front-stage common mode choke coil 36A and a twelfth terminal 37Aa of the first rear-stage common mode choke coil 37A. The seventeenth terminal 38Ab of the first capacitor 38A is connected to the ground terminal 24. That is, the first capacitor 38A is a so-called Y capacitor.

[0028] The second power conversion circuit 30B has a second high potential input terminal 31Ba, a second low potential input terminal 31Bb, and two output terminals 23. The second high potential input terminal 31Ba, the second low potential input terminal 31Bb, and the two output terminals 23 are attached to the metal housing 20. The second high potential input terminal 31Ba is connected to a high potential terminal of the second DC power supply 80B. The second low potential input terminal 31Bb is connected to a low potential terminal of the second DC power supply 80B. The second DC power supply 80B is installed outside the metal housing 20. The second DC power supply 80B is a solar power generation panel separate from the first DC power supply 80A.

[0029] Each output terminal 23 of the second power conversion circuit 30B is the same as each output terminal 23 of the first power conversion circuit 30A. That is, each output terminal 23 is connected to a power system 91 via a power line 90 extending from the output terminal 23 to the outside of the metal casing 20.

[0030] The second power conversion circuit 30B includes a second input capacitor 32B. The second input capacitor 32B has a first terminal 32Ba and a second terminal 32Bb. The first terminal 32Ba of the second input capacitor 32B is connected to the second high potential input terminal 31Ba. The second terminal 32Bb of the second input capacitor 32B is connected to the second low potential input terminal 31Bb. The second power conversion circuit 30B also includes a second inductor 33B. The second inductor 33B has a third terminal 33Ba and a fourth terminal 33Bb. The third terminal 33Ba of the second inductor 33B is connected to the second high potential input terminal 31Ba.

[0031] The second power conversion circuit 30B includes a second rectifier element 34B. The second rectifier element 34B has an 18th terminal 34Ba and a 19th terminal 34Bb. The 18th terminal 34Ba of the second rectifier element 34B is connected to the fourth terminal 33Bb of the second inductor 33B. The 19th terminal 34Bb of the second rectifier element 34B is connected to the output terminal 23 via the inverter 60. The second rectifier element 34B allows a current to flow from the second inductor 33B side to the output terminal 23 side, but does not allow a current to flow from the output terminal 23 side to the second inductor 33B side.

[0032] The second power conversion circuit 30B includes a second switching element 35B. The second switching element 35B has a fifth terminal 35Ba, a sixth terminal 35Bb, and a seventh terminal 35Bc. The second switching element 35B is an N-channel MOSFET (metal oxide semiconductor field effect transistor). The fifth terminal 35Ba of the second switching element 35B is a drain terminal. The sixth terminal 35Bb of the second switching element 35B is a source terminal. The seventh terminal 35Bc of the second switching element 35B is a gate terminal. The fifth terminal 35Ba of the second switching element 35B is connected to the fourth terminal 33Bb of the second inductor 33B. The sixth terminal 35Bb of the second switching element 35B is connected to the second terminal 32Bb of the second input capacitor 32B. The sixth terminal 35Bb of the second switching element 35B is connected to the output terminal 23 via the inverter 60. The seventh terminal 35Bc of the second switching element 35B is connected to the control / drive circuit 50.

[0033] The second power conversion circuit 30B includes an output capacitor 39. This output capacitor 39 is the same as the output capacitor 39 of the first power conversion circuit 30A. In other words, the second power conversion circuit 30B shares the output capacitor 39 with the first power conversion circuit 30A.

[0034] The second power conversion circuit 30B includes a first common mode choke coil and a second common mode choke coil. Hereinafter, in this embodiment, the first common mode choke coil included in the second power conversion circuit 30B is referred to as a "second front-stage common mode choke coil 36B." Also, hereinafter, in this embodiment, the second common mode choke coil included in the second power conversion circuit 30B is referred to as a "second rear-stage common mode choke coil 37B."

[0035] The second front-stage common mode choke coil 36B includes an eighth terminal 36Ba, a ninth terminal 36Bb, a tenth terminal 36Bc, and an eleventh terminal 36Bd. The second front-stage common mode choke coil 36B also includes two coils and a magnetic core 40, which will be described later. The two coils share one magnetic core 40.

[0036] The eighth terminal 36Ba and the ninth terminal 36Bb of the second front-stage common mode choke coil 36B are the same as the two terminals of the other coil. The eighth terminal 36Ba is connected to the second high potential input terminal 31Ba. The ninth terminal 36Bb is connected to the first terminal 32Ba of the second input capacitor 32B via the second rear-stage common mode choke coil 37B.

[0037] The tenth terminal 36Bc and the eleventh terminal 36Bd of the second front-stage common mode choke coil 36B are the same as the two terminals of the other coil. The tenth terminal 36Bc is connected to the second low potential input terminal 31Bb. The eleventh terminal 36Bd is connected to the second terminal 32Bb of the second input capacitor 32B via the second rear-stage common mode choke coil 37B. In this way, the second front-stage common mode choke coil 36B is located between the second high potential input terminal 31Ba and the first terminal 32Ba of the second input capacitor 32B, and between the second low potential input terminal 31Bb and the second terminal 32Bb of the second input capacitor 32B.

[0038] The second rear-stage common mode choke coil 37B includes a twelfth terminal 37Ba, a thirteenth terminal 37Bb, a fourteenth terminal 37Bc, and a fifteenth terminal 37Bd. The second rear-stage common mode choke coil 37B includes two coils and a core that is an annular magnetic body. The two coils share one core.

[0039] The twelfth terminal 37Ba and the thirteenth terminal 37Bb of the second rear-stage common mode choke coil 37B are the same as the two terminals of the other coil. The twelfth terminal 37Ba is connected to the ninth terminal 36Bb of the second front-stage common mode choke coil 36B. The thirteenth terminal 37Bb is connected to the first terminal 32Ba of the second input capacitor 32B.

[0040] The 14th terminal 37Bc and the 15th terminal 37Bd of the second rear stage common mode choke coil 37B are the same as the two terminals of the other coil. The 14th terminal 37Bc is connected to the 11th terminal 36Bd of the second front stage common mode choke coil 36B. The 15th terminal 37Bd is connected to the second terminal 32Bb of the second input capacitor 32B. In this way, the second rear stage common mode choke coil 37B is located between the second front stage common mode choke coil 36B and the first terminal 32Ba of the second input capacitor 32B, and between the second front stage common mode choke coil 36B and the second terminal 32Bb of the second input capacitor 32B. The inductance of the second front stage common mode choke coil 36B is smaller than the inductance of the second rear stage common mode choke coil 37B. Moreover, the inductance of the second front-stage common mode choke coil 36B is substantially the same as the inductance of the first front-stage common mode choke coil 36A.

[0041] The second power conversion circuit 30B includes a second capacitor 38B. The second capacitor 38B has a 16th terminal 38Ba and a 17th terminal 38Bb. The 16th terminal 38Ba of the second capacitor 38B is connected to a wiring between a 9th terminal 36Bb of the second front-stage common mode choke coil 36B and a 12th terminal 37Ba of the second rear-stage common mode choke coil 37B. The 17th terminal 38Bb of the second capacitor 38B is connected to the ground terminal 24. That is, the second capacitor 38B is a so-called Y capacitor.

[0042] The inverter 60 includes a 22nd terminal 60a, a 23rd terminal 60b, a 24th terminal 60c, and a 25th terminal 60d. The 22nd terminal 60a of the inverter 60 is connected to the 20th terminal 39a of the output capacitor 39. The 23rd terminal 60b of the inverter 60 is connected to the 21st terminal 39b of the output capacitor 39. The 24th terminal 60c of the inverter 60 is connected to one output terminal 23. The 25th terminal 60d of the inverter 60 is connected to the other output terminal 23.

[0043] The control and drive circuit 50 is a control unit that controls each power conversion circuit 30. The control and drive circuit 50 outputs a first switching signal S1 to the seventh terminal 35Ac of the first switching element 35A. The first switching signal S1 is a PWM signal, and periodically controls the first switching element 35A to be turned on and off. Similarly, the control and drive circuit 50 outputs a second switching signal S2 to the seventh terminal 35Bc of the second switching element 35B. The control and drive circuit 50 controls the first switching element 35A and the second switching element 35B to turn on and off at different timings. The difference in the on and off timings of each switching element means that the timings at which each switching element turns from off to on are different, or the timings at which each switching element turns from on to off are different.

[0044] Specifically, when the number of the power conversion circuits 30 is N (where N is an integer equal to or greater than 2), the control and drive circuit 50 shifts the switching timing of each switching element of each power conversion circuit 30 by (1 / N) period to control the on-off of each switching element. In this embodiment, the number of the power conversion circuits 30 is two (N=2). Therefore, the control and drive circuit 50 shifts the switching periods of the first switching element 35A and the second switching element 35B by 1 / 2 period to control the on-off of the first switching element 35A and the second switching element 35B. That is, in this embodiment, the phase of the first switching signal S1 and the phase of the second switching signal S2 are opposite phases. Therefore, when the first switching element 35A is on, the second switching element 35B is off, and when the second switching element 35B is on, the first switching element 35A is off.

[0045] (About common mode choke coils) Of the first power conversion circuit 30A configured as described above, a portion other than the first front-stage common mode choke coil 36A is mounted on a substrate 70. Note that in FIG. 2, illustration of each element mounted on the substrate 70 is omitted.

[0046] On the other hand, as shown in FIG. 2, the first front-stage common mode choke coil 36A of the first power conversion circuit 30A includes a first wiring 41A, a second wiring 42A, and a magnetic core 40. One end of the first wiring 41A is connected to the first high potential input terminal 31Aa. The other end of the first wiring 41A is connected to the first terminal 32Aa of the first input capacitor 32A via a connection terminal 71 on the substrate 70. This first wiring 41A constitutes one of the two coils of the first front-stage common mode choke coil 36A. One end of the second wiring 42A is connected to the first low potential input terminal 31Ab. The other end of the second wiring 42A is connected to the second terminal 32Ab of the first input capacitor 32A via the connection terminal 71 on the substrate 70. The second wiring 42A constitutes one of the two coils of the first front-stage common mode choke coil 36A, which is different from the one constituted by the first wiring 41A. Although not shown in the drawings, the first wiring 41A and the second wiring 42A each have a conductor wiring and an insulating film that covers the conductor wiring.

[0047] The magnetic core 40 is substantially cylindrical. The material of the magnetic core 40 includes a magnetic material such as ferrite. The magnetic core 40 surrounds the first wiring 41A and the second wiring 42A. In other words, the first wiring 41A and the second wiring 42A are inserted into a central hole of the magnetic core 40.

[0048] As shown in FIG. 2, the second front-stage common mode choke coil 36B of the second power conversion circuit 30B includes a first wiring 41B, a second wiring 42B, and a magnetic core 40. One end of the first wiring 41B is connected to the second high potential input terminal 31Ba. The other end of the first wiring 41B is connected to the first terminal 32Ba of the second input capacitor 32B via a connection terminal 71 on the substrate 70. This first wiring 41B constitutes one of the two coils of the second front-stage common mode choke coil 36B. One end of the second wiring 42B is connected to the second low potential input terminal 31Bb. The other end of the second wiring 42B is connected to the second terminal 32Bb of the second input capacitor 32B via a connection terminal 71 on the substrate 70. The second wiring 42B constitutes one of the two coils of the second front-stage common mode choke coil 36B, which is different from the coil constituted by the first wiring 41B. Although not shown in the figure, the first wiring 41B and the second wiring 42B each have a conductor wiring and an insulating film that covers the conductor wiring.

[0049] The magnetic core 40 surrounds not only the first wiring 41A and the second wiring 42A in the first power conversion circuit 30A, but also the first wiring 41B and the second wiring 42B in the second power conversion circuit 30B. That is, the first front-stage common mode choke coil 36A and the second front-stage common mode choke coil 36B share the same magnetic core 40.

[0050] Here, the length of the magnetic core 40 shared by each first common mode choke coil in the direction along the central axis of the magnetic core 40 is defined as dimension L1. In this case, the dimension L1 of the magnetic core 40 is 1 / 10 or more of the wiring length L2 of one wiring selected from the first wiring 41A or the second wiring 42A of the first front-stage common mode choke coil 36A, or the second front-stage common mode choke coil 36B or the first wiring 41B or the second wiring 42B. The central axis of the magnetic core 40 refers to a straight line connecting the geometric center of a plane figure formed by the opening edge on each input terminal side and the geometric center of a plane figure formed by the opening edge on each second common mode choke coil side in the through hole of the cylindrical magnetic core 40. Also, the wiring length L2 of the first wiring 41A of the first front-stage common mode choke coil 36A is the length of the wiring from the first high potential input terminal 31Aa to the connection terminal 71. The wiring length L2 of the second wiring 42A of the first front-stage common mode choke coil 36A is the wiring length from the first low potential input terminal 31Ab to the connection terminal 71. The wiring length L2 of the first wiring 41B of the second front-stage common mode choke coil 36B is the wiring length from the second high potential input terminal 31Ba to the connection terminal 71. The wiring length L2 of the second wiring 42B of the second front-stage common mode choke coil 36B is the wiring length from the second low potential input terminal 31Bb to the connection terminal 71. Note that in FIG. 2, the wiring length L2 of the second wiring 42B of the second front-stage common mode choke coil 36B is shown.

[0051] (Effects of this embodiment) (1) According to the above embodiment, the first front-stage common mode choke coil 36A of the first power conversion circuit 30A is connected to the first high potential input terminal 31Aa and the first low potential input terminal 31Ab. This makes it possible to reduce the parasitic capacitance formed between the wiring near each input terminal and the metal housing 20. Therefore, noise caused by the current flowing through this parasitic capacitance can be efficiently suppressed. For example, the current flowing through the parasitic capacitance includes a common mode current. That is, common mode noise can be efficiently suppressed. This also applies to the second front-stage common mode choke coil 36B, the second high potential input terminal 31Ba, and the second low potential input terminal 31Bb of the second power conversion circuit 30B.

[0052] On the other hand, the timing of switching on and off of the first switching element 35A and the second switching element 35B is shifted. Therefore, the timing of switching on and off of the switching elements of the first power conversion circuit 30A and the switching elements of the second power conversion circuit 30B do not match. Therefore, the peaks of the current caused by the switching operation of the on / off control of each switching element do not overlap, so that large noise can be suppressed. For example, the current caused by the switching operation includes a common mode current. In other words, the peaks of the common mode current caused by the switching operation of each switching element do not overlap, so that common mode noise can be reduced.

[0053] (2) According to the above embodiment, the first high potential input terminal 31Aa and the first low potential input terminal 31Ab of the first power conversion circuit 30A are attached to the metal housing 20. The contact points between the first power conversion circuit 30A and the metal housing 20 tend to be paths for noise currents. Therefore, by attaching each input terminal connected to the first front-stage common mode choke coil 36A to the metal housing 20, noise can be efficiently suppressed. The same applies to the second power conversion circuit 30B, the second high potential input terminal 31Ba, the second low potential input terminal 31Bb, and the second front-stage common mode choke coil 36B.

[0054] (3) In particular, in the above embodiment, the on-off switching timing of the first switching element 35A and the second switching element 35B is shifted by (1 / N) cycles. That is, the on-off timing of the switching elements of the first power conversion circuit 30A and the second power conversion circuit 30B is inverted. It is the furthest in one cycle from the peak of the potential in the second power conversion circuit 30B. Therefore, the common mode currents caused by the switching operations of the switching elements cancel each other out, and the common mode current becomes smaller. As the common mode current becomes smaller, the common mode noise becomes smaller.

[0055] (4) According to the above embodiment, the first front-stage common mode choke coil 36A of the first power conversion circuit 30A has a substantially cylindrical magnetic core 40. The first wiring 41A and the second wiring 42A of the first front-stage common mode choke coil 36A are bundled by this magnetic core 40. As a result, the distance between the metal housing 20 and each of the above wirings is physically greater than when the first front-stage common mode choke coil 36A is directly mounted on the substrate 70. Accordingly, the parasitic capacitance formed between each of the wirings of the first front-stage common mode choke coil 36A and the metal housing 20 can be reduced. Therefore, the common mode noise caused by the parasitic capacitance can be reduced. The same applies to the second front-stage common mode choke coil 36B of the second power conversion circuit 30B.

[0056] (5) According to the above embodiment, each power conversion circuit 30 has a rear-stage common mode choke coil in addition to the front-stage common mode choke coil. Also, the front-stage common mode choke coil of each power conversion circuit 30 has a small number of turns, and the inductance is smaller than the inductance of the rear-stage common mode choke coil. The small number of turns reduces the parasitic capacitance between the windings, and the inductance is less likely to decrease even at high frequencies, resulting in excellent high-frequency characteristics. With these configurations, it is possible to suppress common mode noise in a wide frequency band that is difficult to suppress using only the front-stage common mode choke coil.

[0057] (6) According to the above embodiment, the dimension L1 of the magnetic core 40 is 1 / 10 or more of the wiring length L2 of each of the first wirings or each of the second wirings. This allows a physical distance to be secured between each input terminal and the substrate 70. Since parasitic capacitance is likely to occur in the wirings near each input terminal, common mode noise caused by this parasitic capacitance can be efficiently suppressed.

[0058] (7) According to the above embodiment, the first power conversion circuit 30A includes the first capacitor 38A. This can further suppress common-mode noise. The same can be said about the second power conversion circuit 30B and the second capacitor 38B.

[0059] (8) According to the above embodiment, the first wiring 41A and the second wiring 42A of the first front-stage common mode choke coil 36A of the first power conversion circuit 30A are cables in which the outer surfaces of the conductor wiring are covered with an insulator. This makes it possible to reduce the parasitic capacitance generated between each wiring and the metal housing 20. Therefore, it is possible to suppress common mode noise. The same applies to the second power conversion circuit 30B.

[0060] <Example of change> The above embodiment and the following modified examples can be implemented in combination with each other to the extent that no technical contradiction occurs.

[0061] The shift in the switching cycle of each switching element in each power conversion circuit 30 does not have to be a (1 / N) cycle. If there is at least a shift in the on / off timing of each switching element, the peaks of the potential of the wiring in each power conversion circuit 30 will not completely coincide. Therefore, the peaks of the common mode current caused by the switching operation of the switching elements of each power conversion circuit 30 do not overlap, and common mode noise can be reduced.

[0062] The number of power conversion circuits 30 is not limited to two. The power conversion device 10 may include three or more power conversion circuits 30. For example, in the example shown in FIG. 3, the power conversion device 10 includes a third power conversion circuit 30C connected to a third DC power source 80C in addition to the first power conversion circuit 30A and the second power conversion circuit 30B. The third power conversion circuit 30C includes a third high potential input terminal 31Ca, a third low potential input terminal 31Cb, a third input capacitor 32C, a third inductor 33C, a third rectifier element 34C, a third switching element 35C, and a third capacitor 38C. The third input capacitor 32C has a first terminal 32Ca and a second terminal 32Cb. The third inductor 33C has a third terminal 33Ca and a fourth terminal 33Cb. The third rectifier element 34C has an 18th terminal 34Ca and a 19th terminal 34Cb. The third switching element 35C has a fifth terminal 35Ca, a sixth terminal 35Cb, and a seventh terminal 35Cc. The third capacitor 38C has a sixteenth terminal 38Ca and a seventeenth terminal 38Cb. The third power conversion circuit 30C shares the same output capacitor 39 with the first power conversion circuit 30A and the second power conversion circuit 30B. The connection relationship of each of these elements and each terminal is the same as that of the first power conversion circuit 30A.

[0063] The third power conversion circuit 30C includes a third front-stage common mode choke coil 36C as the first common mode choke coil and a third rear-stage common mode choke coil 37C as the second common mode choke coil. The third front-stage common mode choke coil 36C includes an eighth terminal 36Ca, a ninth terminal 36Cb, a tenth terminal 36Cc, and an eleventh terminal 36Cd. The third rear-stage common mode choke coil 37C includes a twelfth terminal 37Ca, a thirteenth terminal 37Cb, a fourteenth terminal 37Cc, and a fifteenth terminal 37Cd. The third front-stage common mode choke coil 36C shares the same magnetic core 40 as the first front-stage common mode choke coil 36A and the second front-stage common mode choke coil 36B. The connection relationship between these elements and terminals is the same as that of the first power conversion circuit 30A.

[0064] In this modified example, the control / drive circuit 50 outputs a third switching signal S3 to the seventh terminal 35Cc of the third switching element 35C. The control / drive circuit 50 then shifts the on / off timing of each switching element by (1 / 3) of a period to control the on / off of each switching element.

[0065] The input terminals of the power conversion circuits 30 do not have to be attached to the metal housing 20. Even in this case, the effect described in (1) can be obtained. The switching elements of the power conversion circuits 30 are not limited to the examples in this embodiment. As long as the control and drive circuit 50 can operate the switching elements, elements other than MOSFETs may be used.

[0066] The output capacitor 39 of each power conversion circuit 30 is not limited to the example of this embodiment. For example, a film capacitor may be used as the output capacitor 39. Also, each power conversion circuit 30 does not have to include the output capacitor 39.

[0067] The first power conversion circuit 30A does not have to include the first capacitor 38A. The effect described in (1) can be obtained even if the first capacitor 38A is not included. The same applies to the second capacitor 38B of the second power conversion circuit 30B.

[0068] The inverter 60 may be disposed outside the metal casing 20. In other words, the power conversion device 10 does not need to include the inverter 60. Of the components of each power conversion circuit 30, which elements and wiring are mounted on the substrate 70 is arbitrary. Also, each first common mode choke coil may be mounted on the substrate 70. Even if each first common mode choke coil is mounted on the substrate 70, the effect of suppressing common mode noise due to sharing the magnetic core 40 can be obtained.

[0069] Each power conversion circuit 30 does not need to include a rear-stage common mode choke coil. Also, the inductance of each first common mode choke coil may be equal to or greater than the inductance of each second common mode choke coil. As long as a front-stage common mode choke coil is included, common mode noise can be suppressed more effectively than if no front-stage common mode choke coil is included.

[0070] The first and second wirings of each first common mode choke coil may not have an insulating film covering the conductor wiring. In that case, it is preferable that each conductor wiring is insulated by a method other than covering.

[0071] The number of magnetic cores 40 shared by the multiple power conversion circuits 30 is not limited to one. Two magnetic cores 40 may surround the first wiring and the second wiring of each first common mode choke coil.

[0072] The shape and size of the magnetic core 40 are not limited to the example of this embodiment. For example, the first wiring and the second wiring of each first common mode choke coil may be wound around an annular magnetic core 40. Also, for example, the first wiring and the second wiring of each first common mode choke coil may be surrounded by a plurality of annular magnetic cores 40.

[0073] It is sufficient that the first common mode choke coils of two or more power conversion circuits 30 share the same magnetic core 40. If the power conversion device 10 has three or more power conversion circuits 30, there may be one or more front-stage common mode choke coils that do not share the same magnetic core 40.

[0074] The magnetic core 40 only needs to surround all the first wirings and second wirings of the first common mode choke coils that share the magnetic core 40. However, when there are multiple magnetic cores 40, one magnetic core 40 does not need to surround the first wirings and second wirings of the first common mode choke coils of all the power conversion circuits 30. For example, when the third power conversion circuit 30C is provided in addition to this embodiment, the first common mode choke coils of the first power conversion circuit 30A and the second power conversion circuit 30B may share the magnetic core 40, and the first common mode choke coils of the second power conversion circuit 30B and the third power conversion circuit 30C may share a magnetic core 40 different from the above.

[0075] In the direction along the central axis of the magnetic core 40, the dimension L1 of the magnetic core 40 may be less than 1 / 10 of the wiring length L2 of each of the first wirings or each of the second wirings. As long as the first common mode choke coils of the multiple power conversion circuits 30 share the magnetic core 40, the impedance characteristics of the multiple first common mode choke coils are uniform. Therefore, common mode noise can be suppressed.

[0076] The material of the magnetic core 40 is not limited to ferrite. For example, permalloy may be used. <Additional Notes> The technical ideas that can be derived from the above-described embodiments and modifications will be described below.

[0077] [1] A metal housing; A plurality of power conversion circuits are built into the metal housing; A control unit that controls each of the power conversion circuits; Equipped with Each of the power conversion circuits is a high potential input terminal and a low potential input terminal; An output terminal; an input capacitor having a first terminal and a second terminal, the first terminal connected to the high potential input terminal and the second terminal connected to the low potential input terminal; an inductor having a third terminal and a fourth terminal, the third terminal being connected to the high potential input terminal; a switching element having a fifth terminal, a sixth terminal and a seventh terminal, the fifth terminal being connected to the fourth terminal of the inductor, the sixth terminal being connected to the second terminal of the input capacitor, and a signal being input from the control unit to the seventh terminal; a first common mode choke coil having an eighth terminal, a ninth terminal, a tenth terminal, and an eleventh terminal, the eighth terminal being connected to the high potential input terminal, the ninth terminal being connected to the first terminal of the input capacitor, the ninth terminal being connected to the low potential input terminal, and the eleventh terminal being connected to the second terminal of the input capacitor; Equipped with the first common mode choke coil includes a magnetic core; the first common mode choke coils of the two or more power conversion circuits share the same magnetic core; The control unit controls the on / off of each of the switching elements of each of the power conversion circuits so that the on / off timing of each of the switching elements is staggered.

[0078] [2] The power conversion device according to [1], wherein the high potential input terminal and the low potential input terminal of each of the power conversion circuits are attached to the metal casing.

[0079] [3] When the number of the plurality of power conversion circuits is N (where N is an integer of 2 or more), The power conversion device according to [1] or [2], wherein the control unit controls the on / off timing of each of the switching elements of each of the power conversion circuits by shifting the on / off timing of each of the switching elements by a (1 / N) period.

[0080] [4] Each of the first common mode choke coils includes: a first wiring connected to the high potential input terminal; A second wiring connected to the low potential input terminal; Equipped with The power conversion device according to any one of [1] to [3], wherein the magnetic core is cylindrical and surrounds all of the first wirings and the second wirings of the first common mode choke coil that shares the magnetic core.

[0081] [5] Each of the power conversion circuits is a second common mode choke coil having a twelfth terminal, a thirteenth terminal, a fourteenth terminal, and a fifteenth terminal; the twelfth terminal is connected to the ninth terminal of the first common mode choke coil; the thirteenth terminal is connected to the first terminal of the input capacitor; the 14th terminal is connected to the 11th terminal of the first common mode choke coil; the fifteenth terminal is connected to the second terminal of the input capacitor; The power conversion device according to any one of [1] to [4], wherein an inductance of the first common mode choke coil is smaller than an inductance of the second common mode choke coil.

[0082] [6] Further comprising a substrate on which the second common mode choke coil is mounted, Each of the first common mode choke coils includes: a first wiring connected to the high potential input terminal; A second wiring connected to the low potential input terminal; Equipped with The power conversion device described in [5], wherein the dimension of the magnetic core shared by each of the first common mode choke coils in a direction along the central axis of the magnetic core is 1 / 10 or more of the wiring length of the first wiring or the second wiring.

[0083] [7] The metal housing has a ground terminal, Each of the power conversion circuits is a capacitor having a sixteenth terminal and a seventeenth terminal; the 16th terminal is connected to the 12th terminal of the second common mode choke coil, The power conversion device according to [5] or [6], wherein the seventeenth terminal is connected to the ground terminal. [Explanation of symbols]

[0084] 10...Power conversion device 20…Metal case 30A…First power conversion circuit 30B...Second power conversion circuit 35A…First switching element 35B...Second switching element 36A…First front-stage common mode choke coil 36B…Second front stage common mode choke coil 37A…First rear stage common mode choke coil 37B…Second rear stage common mode choke coil 40…Magnetic core 41A…First wiring 41B…1st wiring 42A…Second wiring 42B…Second wiring 50...Control and drive circuit

Claims

1. A metal housing; A plurality of power conversion circuits are built into the metal housing; A control unit that controls each of the power conversion circuits; Equipped with Each of the power conversion circuits is a high potential input terminal and a low potential input terminal; An output terminal; an input capacitor having a first terminal and a second terminal, the first terminal connected to the high potential input terminal and the second terminal connected to the low potential input terminal; an inductor having a third terminal and a fourth terminal, the third terminal being connected to the high potential input terminal; a switching element having a fifth terminal, a sixth terminal and a seventh terminal, the fifth terminal being connected to the fourth terminal of the inductor, the sixth terminal being connected to the second terminal of the input capacitor, and a signal being input from the control unit to the seventh terminal; a first common mode choke coil having an eighth terminal, a ninth terminal, a tenth terminal, and an eleventh terminal, the eighth terminal being connected to the high potential input terminal, the ninth terminal being connected to the first terminal of the input capacitor, the ninth terminal being connected to the low potential input terminal, and the eleventh terminal being connected to the second terminal of the input capacitor; Equipped with The first common mode choke coil includes a magnetic core, the first common mode choke coils of the two or more power conversion circuits share the same magnetic core; The control unit controls the on / off of each of the switching elements of each of the power conversion circuits so that the on / off timings of the switching elements of each of the power conversion circuits are staggered. Power conversion equipment.

2. The high potential input terminal and the low potential input terminal of each of the power conversion circuits are attached to the metal housing. The power conversion device according to claim 1 .

3. When the number of the plurality of power conversion circuits is N (where N is an integer of 2 or more), The control unit controls the on / off timing of each of the switching elements of each of the power conversion circuits by shifting the on / off timing of each of the switching elements by (1 / N) cycles. The power conversion device according to claim 1 .

4. Each of the first common mode choke coils includes: a first wiring connected to the high potential input terminal; A second wiring connected to the low potential input terminal; Equipped with The magnetic core is cylindrical and surrounds all of the first wirings and the second wirings of the first common mode choke coil that share the magnetic core. The power conversion device according to claim 1 .

5. Each of the power conversion circuits is a second common mode choke coil having a twelfth terminal, a thirteenth terminal, a fourteenth terminal, and a fifteenth terminal; the twelfth terminal is connected to the ninth terminal of the first common mode choke coil; the thirteenth terminal is connected to the first terminal of the input capacitor; the 14th terminal is connected to the 11th terminal of the first common mode choke coil; the fifteenth terminal is connected to the second terminal of the input capacitor; The inductance of the first common mode choke coil is smaller than the inductance of the second common mode choke coil. The power conversion device according to any one of claims 1 to 4.

6. Further comprising a substrate on which the second common mode choke coil is mounted, Each of the first common mode choke coils includes: a first wiring connected to the high potential input terminal; A second wiring connected to the low potential input terminal; Equipped with The dimension of the magnetic core shared by each of the first common mode choke coils in a direction along the central axis of the magnetic core is 1 / 10 or more of the wiring length of the first wiring or the second wiring. The power conversion device according to claim 5 .

7. The metal housing has a ground terminal, Each of the power conversion circuits is a capacitor having a sixteenth terminal and a seventeenth terminal; the sixteenth terminal is connected to the twelfth terminal of the second common mode choke coil, The seventeenth terminal is connected to the ground terminal. The power conversion device according to claim 5 .

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