Flying capacitor circuit, circuit module and power conversion device

Abstract

When switching a current path by a switch, a surge voltage exceeding the withstand voltage of an element sometimes occurs. The present invention provides a flying capacitor circuit including: a plurality of switching elements cascade-connected on a first surface of a substrate; a plurality of rectifying elements cascade-connected on a second surface of the substrate; and at least one capacitor provided in a wiring connecting main terminals of corresponding switching elements and rectifying elements among the plurality of switching elements and the plurality of rectifying elements, with at least a part of the wiring arranged side by side sandwiching the substrate.

Description

Technical Field

[0001] The present invention relates to a flying capacitor circuit, a circuit module, and a power conversion device. Background Art

[0002] Conventionally, in a flying capacitor circuit, the current flowing through the current path provided with a flying capacitor is switched by a switch (for example, refer to Patent Document 1).

[0003] Patent Document 1: International Publication No. 2015 / 037537 Summary of the Invention

[0004] Technical Problem to be Solved by the Invention

[0005] However, when switching the current path by a switch, a surge voltage exceeding the element withstand voltage may sometimes be generated.

[0006] Technical Solution for Solving the Technical Problem

[0007] In order to solve the above problems, a first aspect of the present invention provides a flying capacitor circuit. The flying capacitor circuit may include a plurality of switch elements connected in cascade on a first surface of a substrate. The flying capacitor circuit may include a plurality of rectifying elements connected in cascade on a second surface of the substrate. The flying capacitor circuit may include at least one capacitor provided in a wiring connecting corresponding main terminals of the switch element and the rectifying element among the plurality of switch elements and the plurality of rectifying elements. At least a part of the wiring may be arranged side by side with the substrate interposed therebetween.

[0008] The plurality of switch elements and the plurality of rectifying elements may be connected in cascade on straight lines parallel to each other.

[0009] The plurality of switch elements and the plurality of rectifying elements may be connected in cascade on the same straight line when viewed from above.

[0010] The flying capacitor circuit may include at least one capacitor in each of a plurality of wirings connecting corresponding main terminals of the switch element and the rectifying element among the plurality of switch elements and the plurality of rectifying elements, except for a wiring connecting the main terminal on the most outer end side of the plurality of switch elements connected in cascade and the main terminal on the most outer end side of the plurality of rectifying elements connected in cascade.

[0011] The number of capacitors provided between corresponding main terminals of a set of switch elements and rectifying elements among the plurality of switch elements and the plurality of rectifying elements may be different from the number of capacitors provided between corresponding main terminals of other sets of switch elements and rectifying elements.

[0012] The number of capacitors provided between the main terminals of the switching elements and the rectifying elements located on the input terminal side of the flying capacitor circuit among a plurality of switching elements and a plurality of rectifying elements may be different from the number of capacitors provided between the main terminals of the switching elements and the rectifying elements located on the output terminal side.

[0013] Each wiring may be provided in a straight line shape on the first surface and the second surface, respectively.

[0014] Each wiring may have a connection direction extension portion on the first surface and the second surface, respectively, and the connection direction extension portion extends along the current path of a plurality of switching elements or a plurality of rectifying elements connected in cascade on the surface. At least one capacitor may be provided in the connection direction extension portion.

[0015] At least one capacitor may be a plurality of capacitors connected in series with the wiring and arranged on the first surface and the second surface.

[0016] Among the plurality of capacitors, the capacitors arranged on the first surface and the capacitors arranged on the second surface may be arranged offset from each other in a top view.

[0017] Each switching element and each rectifying element may be arranged offset from each other in a top view.

[0018] The flying capacitor circuit may further include a heat sink provided at at least one of a position facing each capacitor with the substrate interposed therebetween, a position facing each switching element, and a position facing each rectifying element.

[0019] Each rectifying element may be a switching element.

[0020] The flying capacitor circuit may be an inverter. An output terminal may be provided at the midpoint of a wiring connecting the main terminal of the most end side of a plurality of switching elements connected in cascade and the main terminal of the most end side of a plurality of rectifying elements connected in cascade. The main terminal of the most other end side of a plurality of switching elements connected in cascade and the main terminal of the most other end side of a plurality of rectifying elements connected in cascade may be input terminals of direct current.

[0021] The flying capacitor circuit may include a plurality of first drive circuits arranged on the first surface for independently driving a plurality of switching elements. The flying capacitor circuit may include a plurality of second drive circuits arranged on the second surface for independently driving a plurality of rectifying elements each serving as a switching element. Each first drive circuit and each second drive circuit may be arranged offset from each other in a top view.

[0022] Each rectifying element may be a diode.

[0023] A second aspect of the present invention provides a circuit module. The circuit module may include a switching element mounted on the first side of a substrate. The circuit module may include a rectifying element mounted on the second side of the substrate. The circuit module may include at least one capacitor disposed on a wiring connecting the main terminals of the switching element and the rectifying element. At least a portion of the wiring may be arranged side by side with the substrate interposed therebetween.

[0024] The circuit module may include, at one end thereof, a first connection terminal connected to the first main terminal of the switching element and a second connection terminal connected to the first main terminal of the rectifying element. The circuit module may include, at the other end thereof, a third connection terminal connected to the second main terminal of the switching element and a fourth connection terminal connected to the second main terminal of the rectifying element.

[0025] A third aspect of the present invention provides a flying capacitor circuit. The flying capacitor circuit may cascade-connect a plurality of circuit modules of the second aspect.

[0026] A fourth aspect of the present invention provides a power conversion device. The power conversion device may include a flying capacitor circuit of the first aspect or the third aspect. The power conversion device may include a DC power supply that supplies DC power to the flying capacitor circuit.

[0027] The above summary of the invention does not list all the necessary features of the present invention. Sub-combinations of these feature groups may also form an invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shows the power conversion device 1 according to the present embodiment.

[0029] Figure 2 Shows the relationship between the on / off states of the switching elements 21, 22 and the output voltage of the flying capacitor circuit 2.

[0030] Figure 3 Shows the current path through the third wiring 28.

[0031] Figure 4 Shows the flying capacitor circuit 2 according to the modification.

[0032] Figure 5 Shows the flying capacitor circuit 2 according to the modification.

[0033] Figure 6 Shows the circuit module 5 according to the modification.

[0034] Figure 7 Shows Figure 6 the appearance of the circuit module 5.

[0035] Figure 8 ShowsFigure 6 The current path through the third wiring 28 in the flying capacitor circuit 2 obtained by cascading five stages of circuit modules

[0036] Figure 9 Represents the flying capacitor circuit 2 according to the modified example.

[0037] Figure 10 Represents the flying capacitor circuit 2 according to the modified example.

[0038] Figure 11 Represents a modified example of the arrangement positions of the switching elements 21 and 22.

[0039] Figure 12 Represents the flying capacitor circuit 2 according to the modified example.

[0040] Figure 13 Represents the flying capacitor circuit 2 according to the modified example.

[0041] Figure 14 Represents the flying capacitor circuit 2 according to the modified example.

[0042] Figure 15 Represents the power conversion device 1 according to the modified example. Detailed implementation mode

[0043] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention described in the claims. In addition, the combinations of the features described in the embodiments are not all necessary for the technical means for solving the technical problems of the present invention.

[0044] [1. Structure of the power conversion device 1]

[0045] Figure 1 Represents the power conversion device 1 according to the present embodiment. The power conversion device 1 includes a DC power supply 10, a flying capacitor circuit 2, and an LC filter 11.

[0046] [1-1. DC power supply 10]

[0047] The DC power supply 10 supplies DC power Vin to the flying capacitor circuit 2. The DC power supply may be a rectifier circuit that rectifies the AC current supplied by the power system. One or more filter capacitors (not shown) may be provided between the DC power supply 10 and the flying capacitor circuit 2 to filter the DC power Vin supplied by the DC power supply 10. When an AC current is output from the power conversion device 1, two filter capacitors may be provided, and the midpoint thereof may be used as the return path of the AC current.

[0048] [1-2. Flying capacitor circuit 2]

[0049] The flying capacitor circuit 2 can be a multilevel flying capacitor circuit that performs power conversion in a flying capacitor manner. In this embodiment, for example, it is an inverter that converts the DC voltage from the DC power supply 10 into a multilevel voltage. The flying capacitor circuit 2 includes a plurality of switching elements 21, a plurality of rectifying elements (switching elements in this embodiment) 22, and at least one capacitor 25 disposed on the substrate 20.

[0050] Figure 1 In, the flying capacitor circuit 2 is illustrated by dividing it into a portion on the first surface 201 side of the substrate 20, a portion on the second surface 202 side, and a portion between the first surface 201 and the second surface 202. In this embodiment, for example, the flying capacitor circuit 2 is an N + 1 level (N is an integer of 1 or more) flying capacitor circuit, and includes N switching elements 21 (also referred to as switching elements 211 to 21 N ), N switching elements 22 (also referred to as switching elements 221 to 22 N ), and 2N capacitors 25 (also referred to as capacitors 25 a 1 to 25 a N 、25 b 1 to 25 b N ). Here, N is, for example, 3, 7, 13, etc., and may also be other integers. The subscripts "1"... "N" represent element numbers, and the superscripts "a", "b", etc. represent identifiers between elements with the same number. In this embodiment, for example, the switching elements 21 n 、22 n and the capacitor 25 n (n is an integer of 1 ≤ n ≤ N) can correspond to each other.

[0051] [1-2-1. Switching element 21]

[0052] The switching elements 211 to 21 N are cascade-connected on the first surface 201 of the substrate 20. In this embodiment, for example, starting from one end side (the right side in the figure) of the substrate 20 to the other end side, they are cascade-connected in the order of the switching element 211, the switching element 212... the switching element 21 N . Each switching element 21 can be a surface-mounted device, and can have a main terminal 211 (also referred to as main terminals 2111 to 211 N ) on one end side (the right side in the figure) in the connection direction, and a main terminal 212 (also referred to as main terminals 2121 to 212 N ) on the other end side (the left side in the figure). Each of the main terminals 211, 212 can be disposed on the first surface 201. The main terminal can be an external terminal through which the main current flows. Each switching element 21 can also have a control terminal (not shown), and can be driven by a control signal for this control terminal.

[0053] Switching elements 211 to 21 N Can be connected to the intermittently provided first wiring 26 to switch between conduction and non - conduction between the first wirings 26. The first wiring 26 can be provided on the first surface 201 of the substrate 20 or can be provided within the substrate 20.

[0054] [1 - 2 - 2. Switching element 22]

[0055] Switching elements 221 to 22 N Are cascade - connected on the second surface 202 of the substrate 20. In this embodiment, for example, from one end side (right side in the figure) of the substrate 20 to the other end side in the order of switching element 221, switching element 222... switching element 22 N Each switching element 22 can be a surface - mount device and can have a main terminal 221 (also referred to as main terminals 2211 to 221 N ) on one end side in the connection direction (right side in the figure), and a main terminal 222 (also referred to as main terminals 2221 to 222 N ) on the other end side (left side in the figure). Each of the terminals 221, 222 can be arranged within the second surface 202. Each switching element 22 can also have a control terminal (not shown) and can be driven by a control signal for the control terminal.

[0056] Switching elements 221 to 21 N Can be connected to the intermittently provided second wiring 27 to switch between conduction and non - conduction between the second wirings 27. The second wiring 27 can be provided on the second surface 202 of the substrate 20 or can be provided within the substrate 20.

[0057] [1 - 2 - 3. Connection of switching elements 22, 22]

[0058] Switching elements 211 to 21 N And switching elements 221 to 22 N Can be cascade - connected respectively on mutually parallel straight lines. The two straight lines can be the same straight line in a top view. In this embodiment, for example, the straight line extends between one end side (right side in the figure) and the other end side (left side in the figure) of the substrate 20.

[0059] Among the multiple switching elements 21, 22, the corresponding switching elements 21 n And switching element 22 n Of the main terminals 212 n , 222 n (Or main terminals 211 n , 221 n) can be connected to each other by one third wiring 28. The cascade-connected switching elements 211 to 21 N , 221~22 N The switch element 21 located closest to one end (right side in the figure) N ,twenty two N The main terminals 2111 and 2211 may be connected to each other via the third wiring 28. Therefore, in the present embodiment, for example, a total of N+1 third wirings 28 may be provided in the flying capacitor circuit 2.

[0060] Each third wiring 28 is an example of a wiring, and at least a portion thereof is arranged side by side sandwiching the substrate 20. For example, the third wiring 28 may have a first section 281 arranged on the first surface 201 and a second section 282 arranged on the second surface 202, and the first section 281 and the second section 282 are arranged side by side sandwiching the substrate 20 in the entire section.

[0061] The wirings may be arranged side by side with the substrate interposed therebetween so that at least a portion of the wirings overlap in the width direction in plan view, or the wirings may be arranged offset by the thickness of the substrate 20 in plan view. The offset arrangement may be arranged with a position shift.

[0062] Thus, when at least a portion of the third wiring 28 is arranged in parallel with the substrate 20, the sections arranged in parallel play a differential role so that the magnetic fluxes of each other are canceled, thereby reducing the wiring inductance of the third wiring 28. For example, compared with the case where the third wiring 28 is not arranged in parallel with the substrate 20, the wiring inductance of the third wiring 28 can be reduced to 1 / 10 to 1 / 2 of that case.

[0063] Each third wiring 28 may be arranged in a straight line on the first surface 201 and the second surface 202. For example, the first section 281 and the second section of each third wiring 28 may be arranged in a straight line. The first section 281 may extend in a direction intersecting with the first wiring 26 (e.g., an orthogonal direction), and the second section 282 may extend in a direction intersecting with the second wiring 27 (e.g., an orthogonal direction).

[0064] Each third wiring 28 may have a connection portion 283 between the first section 281 and the second section 282, and the connection portion 283 extends in the thickness direction of the substrate 20 to connect the first section 281 and the second section 282. The connection portion 283 may be, for example, a conductive through hole provided to penetrate the substrate 20, or a copper wire, copper insert, copper clip, etc. provided on the side of the substrate 20.

[0065] The switching elements 211 to 212 are connected in cascade in the plurality of third wirings 28. N , 221~22 NThe midpoint of the third wiring 28 connected to the main terminals 2111 and 2211 on the most distal side (the right side in the figure) may be provided with an output terminal 203. The cascaded switching elements 211 to 21 N 、221 to 22 N The main terminals 212 on the most distal side (the left side in the figure) of N 、222 N may be the input terminals 204 of the direct current Vin. In the present embodiment, for example, the main terminals 212 N 、222 N may be connected to the positive terminal and the negative terminal of the direct current power supply 10.

[0066] [1-2-3. Capacitor 25]

[0067] At least one capacitor 25 is provided in any of the third wirings 28. In the present embodiment, for example, among a total of N + 1 third wirings 28, except for the third wiring 28 provided with the output terminal 203, that is, the third wiring 28 connecting the main terminals 2111 and 2211 on the most distal side (the right side in the figure) of the switching elements 211 to 21 N 、221 to 22 N The other N third wirings 28 may each be provided with at least one capacitor 25. Thus, by turning on and off each of the switching elements 21 and 22, reliable energy exchange can be performed between the capacitors 25, and thus power conversion can be performed. Among the N third wirings 28 other than the third wiring 28 connecting the main terminals 2111 and 2211, capacitors 25 disposed on the first surface 201 a n and capacitors 25 disposed on the second surface 202 b n These two capacitors 25 may be connected in series.

[0068] Each capacitor 25 may be a surface-mounted device or may have terminals at both ends. Each capacitor 25 may be arranged along the third wiring 28 on which the capacitor 25 is provided.

[0069] Here, on the first surface 201, the capacitors 25 provided in two adjacent third wirings 28 in the connection direction of the switching element 21 a (For example, capacitor 25 a N 、25 a (N-1) ) may physically sandwich the switching element 21 (for example, the switching element 21 N ) in between. Similarly, on the second surface 202, the capacitors 25 provided in two adjacent third wirings 28 in the connection direction of the switching element 22 b(e.g., capacitor 25 b N , 25 b (N-1) ) can be physically arranged to sandwich the switching element 22 (e.g., switching element 22 N ) therebetween.

[0070] Capacitor 25 a 1 to 25 a N , 25 b 1 to 25 b N can respectively function as a flying capacitor. According to the number of cascaded connections (i.e., the number of stages, which is the component number in this embodiment) of the switching elements 21 and 22 starting from the output terminal 203, different voltages can be maintained. For example, capacitor 25 a 1, 25 b as a whole can maintain a voltage of 1×Vin / N, and capacitor 25 a 2, 25 b as a whole can maintain a voltage of 2×Vin / N, and capacitor 25 a n , 25 b n as a whole can maintain a voltage of n×Vin / N.

[0071] [1-2-4. Substrate 20]

[0072] Substrate 20 can be formed by connecting multiple substrates 200 (e.g., N substrates 2001 to 200 N ) in this embodiment. In this case, the flying capacitor circuit 2 can be formed by cascading multiple circuit modules 5 (e.g., N circuit modules 51 to 5 N ) each including a substrate 200.

[0073] [1-2-5. Circuit module 5]

[0074] Each circuit module 5 n (where n is an integer for 1≤n≤N) can have a switching element 21 mounted on the first surface 201 of the substrate 200 n , a switching element 22 mounted on the second surface 202, and at least one capacitor 25 provided in the third wiring 28 connecting the main terminals 212 n of the switching element 21 n and the main terminals 222 n of the switching element 22 n n , 222 n n ​​(In this embodiment, there are, for example, two capacitors 25 a n , 25 b n ). At least a part of the third wiring 28 can be arranged side by side with the substrate 200 interposed therebetween n . Thus, at least a part of the third wiring 28 is arranged side by side with the substrate 20 interposed therebetween.

[0075] In addition, each circuit module 5 n can have, at one of its ends (the right end in the figure), a first connection terminal 501 connected to the main terminal 211 n of the switching element 21 n and a second connection terminal 502 connected to the main terminal 221 n of the switching element 22 n . Each circuit module 5 n can have, at the other end (the left end in the figure), a third connection terminal 503 connected to the main terminal 212 n of the switching element 21 n and a fourth connection terminal 504 connected to the main terminal 222 n of the switching element 22 n .

[0076] The first connection terminal 501 can be connected to the third connection terminal 503 of another circuit module 5, and the second connection terminal 502 can be connected to the fourth connection terminal 504 of another circuit module 5. Thus, a plurality of connected circuit modules 5 form the flying capacitor circuit 2. The connection of the first connection terminal 501 to the fourth connection terminal 504 can be achieved by copper wires or copper clips, etc.

[0077] It is preferable to use the following circuit module 5 for each circuit module 5: when the degree of overlap of the third wiring 28 arranged side by side with the substrate 200 is different in a plan view, each time the flying capacitor circuit 2 is formed, the higher the degree of overlap of the third wiring 28 in a front view at a position where the potential difference generated between the main terminals 211 and 221 and / or between the main terminals 212 and 222 is larger. Thus, it is possible to reliably reduce the surge voltage generated due to switching.

[0078] [1-3. LC filter 11]

[0079] The LC filter 11 is connected to the output terminal 203 of the flying capacitor circuit 2. When the power conversion device 1 outputs alternating current, the LC filter 11 can convert the multi-level output voltage output from the flying capacitor circuit 2 into a sine wave. When the flying capacitor circuit 2 outputs direct current, the LC filter can function as a low-pass filter for removing high-frequency noise.

[0080] According to the above flying capacitor circuit 2, at least a part of each of the third wirings 28 that connect the switching elements 21 and 22 via the capacitors 25 is arranged side by side with the substrate 20 in between. Therefore, in this side-by-side arrangement region, the magnetic fluxes of each cancel each other out. As a result, the wiring inductance of the third wiring 28 can be reduced, and the surge voltage generated by the switching of the switching elements 21 and 22 can be lowered.

[0081] In addition, each of the third wirings 28 is arranged linearly on the first surface 201 and the second surface 202, respectively. Therefore, compared with the case where the third wiring 28 is arranged non-linearly, the length of the third wiring 28 can be shortened, thereby reducing its wiring inductance. As a result, the surge voltage generated in the third wiring 28 due to switching can be reliably reduced.

[0082] In addition, since the capacitors 25 are connected in series in the third wiring 28, even if one of the capacitors 25 on the third wiring 28 is damaged, a short circuit of the flying capacitor circuit 2 can be prevented.

[0083] In addition, since the two capacitors 25 connected in series in the third wiring 28 are arranged on the first surface 201 and the second surface 202, respectively, compared with the case where they are arranged on only a single surface, the positions of the third wiring 208 on the first surface 201 and the second surface 22 can be aligned. As a result, the region where the third wiring 28 is arranged side by side with the substrate 20 in between can be made longer, so that the wiring inductance of the third wiring 28 can be reliably reduced, and the surge voltage can be reliably lowered.

[0084] In addition, since the switching elements 211 to 21 N and the switching elements 221 to 22 N are cascade-connected linearly, respectively, compared with the case where they are not cascade-connected linearly, the path of the main current can be shortened, and the wiring inductance of this path can be reduced. As a result, the surge voltage generated in the path of the main current due to switching can be reduced.

[0085] In addition, since the switching elements 211 to 21 N and the switching elements 221 to 22 N are cascade-connected linearly and in parallel with each other, respectively, the lengths of the multiple third wirings 28 can be kept constant. As a result, the surge voltage generated in each of the third wirings 28 can be reduced equally.

[0086] In addition, the switching elements 211 to 21 N and the switching elements 221 to 22 NWhen viewed from above, they are cascaded and connected in a straight line. Therefore, the end of the first section 281 of the first wiring 28 provided on the first surface 201 and the end of the second section 282 of the second wiring 28 provided on the second surface 202 can be aligned on the two surfaces of the substrate 20. As a result, the length of the sections of the third wiring 28 arranged side by side with the substrate 20 in between can be increased. Therefore, the wiring inductance of the third wiring 28 can be reliably reduced, and the surge voltage can be reliably reduced.

[0087] According to the above circuit module 5, at least a part of each of the third wirings 28 connecting the switching elements 21 and 22 through the respective capacitors 25 is arranged side by side with the substrate 20 in between. Therefore, the magnetic fluxes of the respective sections arranged side by side cancel each other out. As a result, the wiring inductance of the third wiring 28 can be reduced, and the surge voltage generated by switching can be reduced.

[0088] In addition, at one end, there is a first connection terminal 501 connected to the main terminal 211 n and a second connection terminal 502 connected to the main terminal 221 n At the other end, there is a third connection terminal 503 connected to the main terminal 212 n and a fourth connection terminal 504 connected to the main terminal 222 n Therefore, by connecting any number of circuit modules 5, a flying capacitor circuit 2 with any number of levels can be formed.

[0089] [2. Operation of the flying capacitor circuit 2]

[0090] Figure 2 It shows the relationship between the on / off states of the respective switching elements 21, 22 and the output voltage of the flying capacitor circuit 2. As shown in this figure, the flying capacitor circuit 2 can generate and output voltages of N + 1 levels from the DC voltage Vin by controlling the on and off of the switching elements 21, 22. The output voltages can be, for example, Vin / 2 (= N·Vin / 2N), (N - 2)·Vin / 2N, (N - 4)·Vin / 2N, (N - 6)·Vin / 2N,..., -Vin / 2 (= (N - 2N)·Vin / 2N).

[0091] [2-1. Current paths in the flying capacitor circuit 2]

[0092] Figure 3 It shows the current paths passing through the third wiring 28. The dashed arrows in the figure indicate the direction of the current flow. The left half of the figure shows the current paths divided into the part on the first surface 201 side of the substrate 20, the part on the second surface 202 side, and the part between the first surface 201 and the second surface 202. The right half of the figure shows the current paths when the flying capacitor circuit 2 is viewed from the side.

[0093] In the flying capacitor circuit 2 according to this embodiment, at least a part of the third wiring 28 provided with the capacitor 25 sandwiches the substrate 20 and is arranged side by side. Therefore, when current flows through the left part of the third wiring 28 as shown in the figure, as shown in the right part of the figure, the regions arranged side by side perform a differential operation with each other so that the magnetic fluxes cancel each other out. As a result, the wiring inductance of the third wiring 28 becomes smaller.

[0094] In the above embodiment, it is described that at least a part of each third wiring 28 sandwiches the substrate 20 and is arranged side by side, but the third wiring 28 provided with the output terminal 203 may not sandwich the substrate 20 and be arranged side by side.

[0095] [3. Modification Example]

[0096] Figure 4 The flying capacitor circuit 2 related to the modification example is shown.

[0097] The flying capacitor circuit 2 may include a third wiring 28A. Each third wiring 28A may have a connection direction extension portion 285 on the first surface 201 and the second surface 202, respectively, and the connection direction extension portion 295 extends along the current path of the switching elements 211 to 21 N or the switching elements 221 to 22 N The first section 281 and the second section 282 of each third wiring 28A may be respectively arranged in a meandering manner within the first surface 201 and the second surface 202, and may have a connection direction extension portion 285 at the front end extending in the direction along the current path far from the switching elements 211 to 21 N or the switching elements 221 to 22 N The connection direction extension portion 285 may extend from the main terminal 211 n (or 221 n ) side towards the other main terminal 212 n (or 222 n ) side. The connection direction extension portion 285 does not necessarily have to be parallel to the current path of the switching elements 211 to 21 N or the switching elements 221 to 22 N .

[0098] Each capacitor 25 may be arranged on the connection direction extension portion 285. In this embodiment, for example, each capacitor 25 n may be arranged along the switching element 21 n or the switching element 22 nSettings are made. When there are three or more capacitors 25 provided in the third wiring 28A, one or more capacitors 25 can be provided on the single connection direction extension portions 285 respectively provided in the first section 281 and the second section 282 of the third wiring 28A. Alternatively, a plurality of connection direction extension portions 285 can be provided in the first section 281 and / or the second section 282, and capacitors 25 can be respectively provided on each connection direction extension portion 285 as an alternative. For example, when a plurality of connection direction extension portions 285 are provided in the first section 281, the first section 281 can be serpentinely arranged within the first surface 201. The third wiring 28 provided with the output terminal 203 (for example, the third wiring 28 connecting the main terminals 2111 and 2211) may not have the connection direction extension portion 285.

[0099] Each third wiring 28A can have a through hole as the connection portion 283. The through hole can be provided at the end of the connection direction extension portion 285 in the first surface 201 and the second surface 202, and connect the connection direction extension portions 285 to each other.

[0100] The flying capacitor circuit 2 can include MOSFETs as the switching elements 21 and 22. The switching elements 21 and 22 can be connected in a reverse cascode manner to each other. In the present embodiment, for example, each switching element 21 has a source terminal on the output terminal 203 side and a drain terminal on the input terminal 204 side, and each switching element 22 has a drain terminal on the output terminal 203 side and a source terminal on the input terminal 204 side. Each of the switching elements 21 and 22 can be connected in reverse parallel with a freewheeling diode. The freewheeling diode can be a parasitic diode of the switching elements 21 and 22 which are MOSFETs. The switching elements 21 and 22 are not limited to MOSFETs, and can also be other switching elements such as IGBTs.

[0101] According to the above flying capacitor circuit 2, each third wiring 28 has a connection direction extension portion 285 extending along the connection direction of the elements, and the capacitor 25 is provided on the connection direction extension portion 285. Therefore, the capacitor 25 can be physically provided at a position other than between the cascaded switching elements 21 and between the switching elements 22, so that the interval between the switching elements 21 and the interval between the switching elements 22 can be shortened, and miniaturization of the flying capacitor circuit 2 can be achieved.

[0102] Figure 5 Shows a flying capacitor circuit 2 according to a modified example.

[0103] The flying capacitor circuit 2 can be between the main terminals 212 of the mutually corresponding switching elements 21 n and the switching element 22 n and the main terminal 222 n and between the main terminals 211 n ​n respectively have a third wiring 28 between them and the main terminal 221 n A capacitor 25 may be provided in each third wiring 28. Thus, a group of switching elements 21 n , 22 n and adjacent other groups of switching elements 21 n+1 , 22 n+1 are connected in parallel with a capacitor 25 therebetween, so that the capacitance between the switching element 21 and the switching element 22 can be increased.

[0104] Figure 6 Fig. shows a circuit module 5 according to a modified example. Each circuit module 5 may have third wirings 28A respectively between the main terminals 212 n and the main terminal 222 n of corresponding switching elements 21 n and between the main terminals 211 n and the main terminal 221 n . n The third wiring 28A connecting the main terminal 212

[0105] and the main terminal 222 n , and the third wiring 28A connecting the main terminal 211 n and the main terminal 221 n may be disposed on opposite sides sandwiching the switching element 21 n or the switching element 22 n on the first surface 201 and the second surface 202. The capacitor 25 n provided in the third wiring 28A connecting the main terminal 212 n and the main terminal 222 n , and the capacitor 25 n provided in the third wiring 28A connecting the main terminal 211 n and the main terminal 221 n may be arranged in the connection direction extension portion 285, so that on the first surface 201 and the second surface 202, the switching element 21 n or the switching element 22 N is sandwiched therebetween in a direction (orthogonal direction in this modified example, for example) intersecting the current paths of the switching elements 211 to 21 N , the switching elements 221 to 22 n or the switching element 22 n .

[0106] Figure 7 Fig. shows Figure 6The appearance of the circuit module 5. In the figure, the upper part represents the appearance of the first surface 201, and the lower part represents the appearance of the second surface 202. Each capacitor 25 may have terminals at both ends and may be arranged along the connection direction extension part 285. Through holes may be provided at the ends of the connection direction extension part 285 as connection parts 283 to connect the connection direction extension parts 285 of the first surface 201 and the second surface 202 to each other.

[0107] Figure 8 Indicates the Figure 6 Current path through the third wiring 28 in the flying capacitor circuit 2 obtained by cascading the circuit modules 5A. In the figure, the illustration of the switching elements 21 and 22 is simplified. Shown are the switching elements 21 n , 22 n-1 , 21 n-2 In the conducting state, the switching element 22 n , 21 n-1 , 22 n-2 The path of the current flowing when in the cut-off state.

[0108] In this modification, as shown by the shaded part in the figure, the third wiring 28A connecting the main terminal 211 n and the main terminal 221 n , and the third wiring 28A connecting the main terminal 211 n-1 and the main terminal 221 n-1 The magnetic fluxes are mutually cancelled in the side-by-side arrangement intervals of the third wiring 28A, respectively, so that the wiring inductance of each third wiring 28A becomes smaller.

[0109] Figure 9 Indicates the flying capacitor circuit 2 according to the modification. In the flying capacitor circuit 2 according to this modification, between the main terminals 211 n , 22 n of the corresponding pair of switching elements 21 n , 221 n and / or between the main terminals 212 n , 222 n , between the main terminals 211 m , 22 m (where m is an integer such that m ≠ n and 1 ≤ m ≤ N) of other pairs of switching elements 21 m , 221 m and / or between the main terminals 212 m , 222 mBetween them, the number of capacitors 25 provided between the main terminals can be different. For example, between the main terminals 211 and 221 on the input terminal 204 side and / or between the main terminals 212 and 222, and / or between the main terminals 211 and 221 on the output terminal 203 side and / or between the main terminals 212 and 222, the number of capacitors 25 provided between the main terminals can be different. More specifically, compared with between the main terminals 211 and 221 and / or between the main terminals 212 and 222 where a smaller potential difference is generated, the number of capacitors 25 connected in series and / or in parallel between the main terminals 211 and 221 and / or between the main terminals 212 and 222 where a larger potential difference is generated is more. In this embodiment, for example, the number of capacitors 25 connected in series and in parallel between the main terminals 211 and 221 on the input terminal 204 side is more than the number of capacitors 25 connected in series and in parallel between the main terminals 211 and 221 on the output terminal 203 side. For example, main terminal 211 n and 221 n has 4 capacitors 25 provided between them, while between main terminal 211 n-2 and 221 n-2 only 1 capacitor 25 is provided. However, it is also possible to increase the capacitance of the capacitors 25 provided between the main terminals 211 n and 221 n (or the main terminals 212 n and 222 n ) instead of increasing the number of capacitors 25 connected in parallel between the main terminals.

[0110] For the corresponding main terminals 211 n and 221 n (or the main terminals 212 n and 222 n ) when capacitors 25 are connected in parallel between them, a plurality of third wirings 28A or connection direction extension portions 285 can be connected in parallel between the main terminals.

[0111] According to the flying capacitor circuit 2 according to this modification, the number of capacitors 25 provided between the main terminals 211 n and 221 n and / or between the main terminals 212 n and 222 n is different from the number of capacitors 25 between the main terminals 211 m and 221 m and / or between the main terminals 212 m and 222 mTherefore, when the number of capacitors 25 connected in series is different, between the main terminals where the number of capacitors 25 is large, the voltage applied to each capacitor 25 can be reduced, thereby preventing the capacitor 25 from being damaged by the voltage application. In addition, when the number of capacitors 25 connected in parallel is different, between the main terminals where the number of capacitors 25 is large, the capacitance can be increased, thereby increasing the amount of energy exchanged with other capacitors 25.

[0112] In addition, since the number of capacitors 25 on the input terminal 204 side and the output terminal 203 side is different, by increasing the number of capacitors 25 connected in series on either side, it is possible to reliably prevent the capacitors 25 from being damaged by voltage application, and by increasing the number of capacitors 25 connected in parallel, the capacitance can be increased, thereby efficiently increasing the amount of energy exchanged with other capacitors 25.

[0113] In this modification, the case where the third wiring 28A having the connection direction extending portion 285 is provided between the main terminals of the switching elements 21 and 22 is described, but the third wiring 28 not having the connection direction extending portion 285 may be provided.

[0114] Figure 10 FIG. 2 shows a flying capacitor circuit 2 according to a modified example. Figure 8 The flying capacitor circuit 2 shown in FIG. Figure 6 However, in the flying capacitor circuit 2 of this modification, the circuit module 5 in the center of the figure is reversely connected. In this case, the flying capacitor circuit 2 can also be reliably used for power conversion.

[0115] Figure 11 FIG. 2 shows a modification of the arrangement positions of the switch elements 21 and 22. In this modification, the switch elements 21 and the switch elements 22 are arranged to be staggered from each other in a plan view. n and each switching element 22 n In this modification, for example, the switching elements 21 and 22 are staggered in the cascade connection direction. Thus, the heat generated by each switching element 21 and 22 can be dissipated from the opposite side of each switching element 21 and 22 through the substrate 20.

[0116] Similarly, although not shown in the figure, the capacitors 25 disposed on the first surface 201 among the plurality of capacitors 25 a and the capacitor 25 disposed on the second surface 202 b For example, two capacitors 25 may be arranged in series in one third wiring 28. a , 25b When disposed on the first surface 201 and the second surface 202, these capacitors 25 a , 25 b can be arranged to be offset from each other in a top view. In this embodiment, for example, the capacitors 25 a , 25 b can be offset along the third wiring 28. Thus, the heat generated by each capacitor 25 can be dissipated from the side opposite to the capacitor 25 through the substrate 20.

[0117] Figure 12 Shows the bootstrap capacitor circuit 2 according to the modified example. The left half of the figure is a view of the bootstrap capacitor circuit 2 observed from the first surface 201 side and the second surface 202 side, and the right half of the figure is a view of the bootstrap capacitor circuit 2 observed from the side. The hollow arrows in the figure indicate the direction of heat flow.

[0118] When the switching elements 21, 22 are arranged to be offset from each other in a top view, at least one of the positions facing each switching element 21 across the substrate 20 and the positions facing each switching element 22 is provided with a heat sink 205. Thus, as shown in the right part of the figure, the heat generated by the switching element 21 or the switching element 22 can be efficiently dissipated. In this modified example, for example, the heat sink 205 is a surface-mounted heat sink. The heat sink 205 can be energized or soldered to the first wiring 26 or the second wiring 27. The heat sink 205 can also be a heat sink in other forms such as a metal plate made of aluminum, iron, copper, etc.

[0119] Similarly, when the capacitors 25 disposed on the first surface 201 a , the capacitors 25 disposed on the second surface 202 b are arranged to be offset from each other in a top view, at least one of the positions facing each capacitor 25 across the substrate 20 can be provided with a heat sink 205. Thus, the heat generated by the capacitor 25 can be efficiently dissipated.

[0120] Figure 13 Shows the bootstrap capacitor circuit 2 according to the modified example. The bootstrap capacitor circuit 2 can include a plurality of drive circuits 23 (also referred to as drive circuits 231 to 23 N ) that independently drive the switching elements 211 to 21 N , and a plurality of drive circuits 24 (also referred to as drive circuits 241 to 24 N ) that independently drive the switching elements 221 to 22 N . Each of the drive circuits 231 to 23 N , 241 to 24 N can be associated with the switching elements 211 to 21 N , 221 to 22N There is a one-to-one correspondence between the two switching elements, and a control signal can be provided to the corresponding switching element 21 or the switching element 22 .

[0121] Among them, the driving circuits 231 to 23 N It is an example of a first driving circuit and can be arranged on the first surface 201. The driving circuits 231 to 23 N The switch elements 211 to 212 of the driving object can be N Similarly, the drive circuits 241 to 24 N It is an example of the second driving circuit and can be arranged on the second surface 202. The driving circuits 241 to 24 N The switch elements 221 to 221 of the driving object can be N The drive circuit 23 and the drive circuit 24 can drive the switch elements 21 and 22 at different potentials, and the ground potentials of the two can be different.

[0122] Figure 14 FIG. 2 shows a flying capacitor circuit 2 according to a modification example. N and drive circuit 241~24 N The drive circuits 23 and 24 can be arranged staggered from each other in a plan view. Thus, the heat generated by each drive circuit 23 and 24 can be dissipated from the side opposite to the drive circuit 23 and 24 via the substrate 20. In addition, the noise generated by the switch can be prevented from affecting the drive circuits 23 and 24 located on the side opposite to the substrate 20, thereby preventing the drive circuits 23 and 24 from malfunctioning.

[0123] The direction in which the drive circuits 23 and 24 are staggered may be the connection direction of the switch element 21 or the switch element 22, or the direction intersecting therewith (e.g., the orthogonal direction). In this figure, the switch elements 21 and the switch elements 22 are also staggered when viewed from above, but the switch elements 21 and 22 may not be staggered while the drive circuits 23 and 24 are staggered. A heat sink 205 may be provided at at least one of the positions sandwiching the substrate 20 and facing the drive circuits 23 and 24.

[0124] Figure 15 2 shows a power conversion device 1 according to a modified example. The flying capacitor circuit 2 of the power conversion device 1 may include a diode 29 as each rectifying element instead of the switch element 21. For example, the flying capacitor circuit 2 may include N diodes 29 (also referred to as diodes 291 to 29 N Each diode 29 may be a surface mounted device, or may have a cathode terminal 291 (also referred to as cathode terminals 2911 to 2912 ) as a main terminal provided at one end (right side in the figure). N) and on the other end side (the left side in the figure), there is provided an anode terminal 292 (also referred to as anode terminals 2921 to 292 N ) and they are cascade-connected.

[0125] In this modification example, for example, the flying capacitor circuit 2 can be a boost chopper circuit. For example, the main terminals 222 of the cascade-connected switching elements 221 to 22 N that are closest to the other end side (the left side in the figure) N and the anode terminals 292 of the cascade-connected diodes 291 to 29 N that are closest to the other end side N are connected to the midpoint of the third wiring 28, and the main terminal 2111 of the cascade-connected switching elements 221 to 22 N that is closest to one end side (the right side in the figure) can be the input terminal 204 of the direct current Vin. Additionally, the main terminal 2111 of the cascade-connected switching elements 221 to 22 N that is closest to one end side (the right side in the figure) and the cathode terminal 2911 of the cascade-connected diodes 291 to 29 N that is closest to one end side can be the output terminal 203 of the direct current. The third wiring 28 provided with the input terminal 204 may not be arranged side by side with the substrate 20 interposed therebetween.

[0126] The power conversion device 1 can include an inductor 290 between the DC power supply 10 and the flying capacitor circuit 2. In this embodiment, for example, the inductor 290 is provided between the positive terminal of the DC power supply 10 and the positive input terminal 204 of the flying capacitor circuit 2, but it can also be provided between the negative terminal of the DC power supply 10 and the negative input terminal 204 of the flying capacitor circuit 2. The inductor 290 can accumulate energy by flowing a current when one of the switching elements 221 to 22 N is turned on and release the energy in the form of a current when the switching element is turned off.

[0127] According to the above flying capacitor circuit 2, with the diode 29 as a rectifying element, the flying capacitor circuit 2 can be used as a chopper. In this modification example, the case where the flying capacitor circuit 2 is a boost chopper is described, but it can also be a buck chopper.

[0128] [4. Other Modification Examples]

[0129] In the above-described embodiments and modification examples, the case where the flying capacitor circuit 2 is formed by cascade-connecting a plurality of circuit modules 5 is described, but it can also be integrally formed on the substrate 20 without using the circuit module 5.

[0130] In addition, the case where the power conversion device 1 has only one flying capacitor circuit 2 has been described, but a plurality of flying capacitor circuits 2 may be provided in parallel. The plurality of flying capacitor circuits 2 may be provided on the same substrate 20 or on independent substrates 20. When the plurality of flying capacitor circuits 2 each function as an inverter, the entire power conversion device 1 may function as a single-phase inverter or a three-phase or polyphase inverter.

[0131] As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made based on the above embodiments. According to the description of the patent claims, the embodiments in which the above various changes or improvements are made are also included in the technical scope of the present invention.

[0132] It should be noted that as long as the execution order of each process such as the actions, sequences, steps, and stages of the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is not specifically shown as "before" or "previously", or when the subsequent process uses the output of the previous process, it can be implemented in any order. In the action flow in the claims, the specification, and the drawings, for convenience of explanation, "first", "then", etc. are used, but it does not mean that it must be implemented in such an order.

[0133] Reference Numeral Explanation

[0134] 1 Power conversion device; 2 Flying capacitor circuit; 5 Circuit module; 10 DC power supply; 11 LC filter; 20 Substrate; 21 Switching element; 22 Switching element; 23 Driving circuit; 24 Driving circuit; 25 Capacitor; 26 First wiring; 27 Second wiring; 28 Third wiring; 29 Diode; 200 Substrate; 201 First surface; 202 Second surface; 203 Output terminal; 204 Input terminal; 205 Heat sink; 211 Main terminal; 212 Main terminal; 221 Main terminal; 222 Main terminal; 281 First interval; 282 Second interval; 283 Connection portion; 285 Connection direction extension portion; 290 Inductor; 291 Cathode terminal; 292 Anode terminal; 501 First connection terminal; 502 Second connection terminal; 503 Third connection terminal; 504 Fourth connection terminal.

Claims

1. A flying capacitor circuit, characterized in that, Comprising: A plurality of switching elements cascade-connected on the first surface of the substrate; A plurality of rectifying elements cascade-connected on the second surface of the substrate; And At least one capacitor disposed in a wiring connecting the main terminals of the corresponding switching element and rectifying element among the plurality of switching elements and the plurality of rectifying elements, At least a part of the wiring is arranged side by side with the substrate interposed therebetween, Each wiring has a connection direction extension portion on the first surface and the second surface, and the connection direction extension portion extends along the current path of the plurality of switching elements or the plurality of rectifying elements cascade-connected on that surface, The at least one capacitor is disposed in the connection direction extension portion.

2. The flying capacitor circuit according to claim 1, wherein The plurality of switching elements and the plurality of rectifying elements are cascade-connected on mutually parallel straight lines.

3. The flying capacitor circuit according to claim 1 or 2, wherein The plurality of switching elements and the plurality of rectifying elements are cascade-connected on the same straight line when viewed from above.

4. The flying capacitor circuit according to claim 1 or 2, wherein Among the multiple wirings connecting the main terminals of the corresponding switching element and rectifying element among the plurality of switching elements and the plurality of rectifying elements, in other wirings except the wiring connecting the main terminal of the most end-side of the cascade-connected plurality of switching elements and the main terminal of the most end-side of the cascade-connected plurality of rectifying elements, each has the at least one capacitor.

5. The flying capacitor circuit according to claim 4, wherein Among the plurality of switching elements and the plurality of rectifying elements, the number of capacitors provided between the main terminals of the switching element and the rectifying element on the input terminal side of the flying capacitor circuit is different from the number of capacitors provided between the main terminals of the switching element and the rectifying element on the output terminal side.

6. The flying capacitor circuit according to claim 1 or 2, wherein Each wiring is arranged in a straight line shape on the first surface and the second surface respectively.

7. The flying capacitor circuit according to claim 1 or 2, wherein The at least one capacitor includes a plurality of capacitors connected in series in the wiring and disposed on the first surface and the second surface.

8. The flying capacitor circuit according to claim 7, wherein The capacitors disposed on the first surface and the capacitors disposed on the second surface among the plurality of capacitors are arranged offset from each other when viewed from above.

9. The flying capacitor circuit according to claim 1 or 2, wherein Each switching element and each rectifying element are arranged offset from each other when viewed from above.

10. The flying capacitor circuit according to claim 8, wherein The flying capacitor circuit further includes a heat sink, and the heat sink is disposed at at least one of a position facing each capacitor with the substrate interposed therebetween, a position facing each switching element, and a position facing each rectifying element.

11. The flying capacitor circuit according to claim 9, wherein The flying capacitor circuit further includes a heat sink, which is disposed at at least one of a position facing the substrate and each capacitor, a position facing each switching element, and a position facing each rectifying element.

12. The flying capacitor circuit according to claim 1 or 2, wherein each rectifying element is a switching element.

13. The flying capacitor circuit according to claim 12, wherein the flying capacitor circuit is an inverter, an output terminal is provided at a midpoint of a wiring connecting a main terminal on the most one - end side of the plurality of cascaded switching elements and a main terminal on the most one - end side of the plurality of cascaded rectifying elements, main terminals on the most other - end side of the plurality of cascaded switching elements and main terminals on the most other - end side of the plurality of cascaded rectifying elements are DC input terminals.

14. The flying capacitor circuit according to claim 1 or 2, wherein each rectifying element is a diode.

15. A flying capacitor circuit, characterized in that, comprising: a plurality of switching elements cascaded on a first surface of the substrate; a plurality of rectifying elements cascaded on a second surface of the substrate; and at least one capacitor provided in a wiring connecting main terminals of corresponding switching elements and rectifying elements among the plurality of switching elements and the plurality of rectifying elements, at least a part of the wiring is arranged side by side with the substrate interposed therebetween, the number of capacitors provided between main terminals of a corresponding set of switching elements and rectifying elements among the plurality of switching elements and the plurality of rectifying elements is different from the number of capacitors provided between main terminals of other sets of switching elements and rectifying elements.

16. The flying capacitor circuit according to claim 15, wherein among the plurality of switching elements and the plurality of rectifying elements, the number of capacitors provided between main terminals of a switching element and a rectifying element on the input terminal side of the flying capacitor circuit is different from the number of capacitors provided between main terminals of a switching element and a rectifying element on the output terminal side.

17. The flying capacitor circuit according to claim 15 or 16, wherein each wiring is arranged in a straight line on the first surface and the second surface respectively.

18. The flying capacitor circuit according to claim 15 or 16, wherein the at least one capacitor includes a plurality of capacitors connected in series in the wiring and arranged on the first surface and the second surface.

19. The flying capacitor circuit according to claim 18, wherein capacitors arranged on the first surface and capacitors arranged on the second surface among the plurality of capacitors are arranged offset from each other in a top view.

20. The flying capacitor circuit according to claim 15 or 16, wherein each switching element and each rectifying element are arranged offset from each other in a top view.

21. The flying capacitor circuit according to claim 19, wherein the flying capacitor circuit further includes a heat sink, which is disposed at at least one of a position facing the substrate and each capacitor, a position facing each switching element, and a position facing each rectifying element.

22. The flying capacitor circuit according to claim 20, wherein the flying capacitor circuit further includes a heat sink, which is disposed at at least one of positions facing the substrate and facing each capacitor, positions facing each switching element, and positions facing each rectifying element.

23. The flying capacitor circuit according to claim 15 or 16, wherein each rectifying element is a switching element.

24. The flying capacitor circuit according to claim 23, wherein the flying capacitor circuit is an inverter, an output terminal is provided at the midpoint of a wiring connecting the main terminal on the most one end side of the plurality of cascaded switching elements and the main terminal on the most one end side of the plurality of cascaded rectifying elements, the main terminals on the most other end side of the plurality of cascaded switching elements and the main terminals on the most other end side of the plurality of cascaded rectifying elements are DC input terminals.

25. The flying capacitor circuit according to claim 15 or 16, wherein each rectifying element is a diode.

26. A flying capacitor circuit, characterized in that, comprising: a plurality of switching elements cascade-connected on the first surface of the substrate; a plurality of rectifying elements cascade-connected on the second surface of the substrate; and at least one capacitor provided in a wiring connecting the main terminals of the corresponding switching element and rectifying element among the plurality of switching elements and the plurality of rectifying elements, at least a part of the wiring is arranged side by side with the substrate in between, each rectifying element is a switching element, the flying capacitor circuit further includes: a plurality of first driving circuits arranged on the first surface and independently driving the plurality of switching elements; and a plurality of second driving circuits arranged on the second surface and independently driving the plurality of rectifying elements, wherein the plurality of rectifying elements are respectively switching elements, each first driving circuit and each second driving circuit are arranged to be offset from each other in a plan view.

27. A circuit module, characterized in that, comprising: a switching element mounted on the first surface of the substrate; a rectifying element mounted on the second surface of the substrate; and at least one capacitor provided in a wiring connecting the main terminals of the switching element and the rectifying element, at least a part of the wiring is arranged side by side with the substrate in between, the wiring has connection direction extending portions on the first surface and the second surface, and the connection direction extending portions extend from one main terminal side to the other main terminal side among the two main terminals of the switching element and the two main terminals of the rectifying element to which the wiring is connected, the at least one capacitor is provided in the connection direction extending portion.

28. The circuit module according to claim 27, wherein at one end, a first connection terminal connected to the first main terminal of the switching element and a second connection terminal connected to the first main terminal of the rectifying element are provided, at the other end, a third connection terminal connected to the second main terminal of the switching element and a fourth connection terminal connected to the second main terminal of the rectifying element are provided.

29. A flying capacitor circuit, wherein It is formed by cascading a plurality of circuit modules described in claim 28.

30. A power conversion device, characterized in that, It includes: A flying capacitor circuit according to any one of claims 1 to 26 and 29; And A DC power supply that supplies direct current to the flying capacitor circuit.

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