Power conversion device

Abstract

To improve the cooling capacity of a power semiconductor and the positioning accuracy of a shield in a power conversion device.SOLUTION: A lower frame 30 includes: a bus bar 31 that is connected to an AC terminal 41; a pair of shields 33 that are erected from side edges on both sides of the bus bar 31; and a lower frame opening portion 32 that is cut out at a position that overlaps with a main body portion of a power semiconductor 40 at the time of assembly. An upper frame 50 includes: a slit 53 formed at a position through which the shield 33 penetrates at the time of assembly; an upper frame opening 51 that is cut out at a position that overlaps with a body part of the power semiconductor 40 and the AC terminal 41 at the time of assembly; and a leaf spring 52 erected from a side surface of the upper frame opening 51 toward an inside of the upper frame opening 51. A current sensor is mounted on a substrate at a position overlapping with the bus bar 31 at the time of assembly. The power semiconductor 40 is fixed to a cooler 10 in a state of being sandwiched between the upper frame 50 and the lower frame 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art In power conversion devices, a technique is often used in which power semiconductors including switching elements are cooled by contacting them with a cooler.

[0003] In addition, in power conversion devices, a current sensor is often placed near a bus bar connected to the input or output terminal of a power semiconductor to detect the output current flowing through the bus bar. The output current detected by the current sensor is used for control and overcurrent protection.

[0004] Patent Document 1 discloses a prior art power conversion device including a power semiconductor, a cooler, and a current sensor.

[0005] Furthermore, a technique of using a metal shield near the current sensor and the bus bar is known as a measure to prevent malfunction of the current sensor due to noise. Patent Document 2 discloses a prior art related to a shield for a current sensor.

[0006] This shield has the effect of preventing current sensor malfunction due to noise caused by current flowing through the bus bar of an adjacent phase, particularly in a three-phase power conversion device having a current sensor and a shield for each phase. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-81308 A [Patent Document 2] JP 2022-138206 A Summary of the Invention [Problem to be solved by the invention]

[0008] In order for the power semiconductor to obtain sufficient cooling performance, the power semiconductor needs to be brought into contact with the cooler under pressure.

[0009] Furthermore, any deviation in the position of the shield adversely affects the detection accuracy of the current sensor, so accurate positioning of the shield is required when assembling the power conversion device.

[0010] In view of the above, it is necessary to improve the cooling capacity of the power semiconductors and the positioning accuracy of the shield in the power conversion device. [Means for solving the problem]

[0011] The present invention has been devised in view of the above-mentioned problems in the related art, and one aspect thereof is a power conversion device having a power semiconductor, the power semiconductor having a cooling surface on a surface of a main body portion facing the cooler and having an AC terminal, a bus bar provided between the cooler and the power semiconductor and connected to the AC terminal, a pair of shields erected from both side edges of the bus bar toward the power semiconductor, and a lower frame opening portion having a cutout at a position that will overlap the main body portion of the power semiconductor during assembly, and the upper frame having a slit provided on the side of the power semiconductor and formed at a position where the shield will pass through during assembly, an upper frame opening cut out at a position that will overlap the main body of the power semiconductor and the AC terminal during assembly, and a leaf spring erected from a side of the upper frame opening toward the inside of the upper frame opening; and a substrate arranged on the opposite side of the power semiconductor with respect to the upper frame, the substrate having a current sensor mounted at a position where the current sensor will overlap the bus bar during assembly, the power semiconductor being fixed to the cooler while being sandwiched between the upper frame and the lower frame.

[0012] In one aspect, the power supply device is characterized in that it further comprises an insulating plate disposed between the lower frame and the cooler, and the power semiconductor is of a non-insulated type.

[0013] In one embodiment, the bus bar and the shield are insert molded into the lower frame.

[0014] In one aspect, the power supply circuit outputs a multi-phase AC power, and includes the current sensor and the shield corresponding to the bus bar of each phase. Effect of the Invention

[0015] According to the present invention, in a power conversion device, it is possible to improve the cooling capacity of a power semiconductor and improve the positioning accuracy of a shield. [Brief description of the drawings]

[0016] [Figure 1] 1 is an exploded perspective view showing a power conversion device according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of a power conversion device according to the present invention will be described in detail with reference to FIG.

[0018] [Embodiment] The configuration of the power semiconductor and its peripheral components provided in the power conversion device of this embodiment is shown in Fig. 1. The power conversion device is, for example, an inverter capable of outputting multi-phase (three-phase in Fig. 1) AC power.

[0019] 1, the power converter of the present embodiment is configured by stacking, from the bottom up, a cooler 10, an insulating plate 20, a lower frame 30, power semiconductors 40, and an upper frame 50. In addition, screws 60 are provided for attaching the insulating plate 20, the lower frame 30, the power semiconductors 40, and the upper frame 50 to the cooler 10.

[0020] Each part will be described in detail below.

[0021] Each of the three power semiconductors 40 includes an AC terminal 41, a P terminal 42, and an N terminal 43. The AC terminal 41, the P terminal 42, and the N terminal 43 are provided on the side surfaces of the main body of the power semiconductor 40 in an upright manner.

[0022] 1 has an internal configuration in which two semiconductor switching elements are connected in series. The two semiconductor switching elements may be, for example, an upper arm IGBT and a lower arm IGBT.

[0023] The collector terminal of the upper arm IGBT is connected to a P terminal 42. The emitter terminal of the lower arm IGBT is connected to an N terminal 43. The emitter terminal of the upper arm IGBT and the collector terminal of the lower arm IGBT are connected to an AC terminal 41.

[0024] The back surface (the surface facing the cooler 10) of the main body of the power semiconductor 40 serves as a cooling surface. The power semiconductor 40 of this embodiment is a non-insulated type, and an electrode is exposed on the back surface of the power semiconductor 40 and acts as a cooling surface. This electrode has the same potential as the P terminal 42, N terminal 43, or AC terminal 41 of the power semiconductor 40.

[0025] The lower frame 30 is made of, for example, resin. The lower frame 30 is disposed between the cooler 10 and the power semiconductor 40. The lower frame 30 has a lower frame opening 32 formed at a position corresponding to the main body of the power semiconductor 40 (a position that overlaps during assembly). The lower frame 30 also includes a bus bar 31 connected to an AC terminal 41 of the power semiconductor 40, a P-side bus bar 34 connected to a P-terminal 42 of the power semiconductor 40, and an N-side bus bar 35 connected to an N-terminal 43 of the power semiconductor 40.

[0026] One end of bus bar 31, P-side bus bar 34, and N-side bus bar 35 is located in the vicinity of lower frame opening 32, and the other end extends toward the outer periphery of lower frame 30. The other ends of bus bar 31, P-side bus bar 34, and N-side bus bar 35 are connected to, for example, a load-side component (such as a filter) or a terminal block (not shown) of the power conversion device.

[0027] A pair of shields 33 stand upright from both sides of the side edges of the busbar 31 (side edges at both ends in the short direction perpendicular to the extension direction of the busbar 31) toward the power semiconductor 40 (upper side in FIG. 1). The shield 33 may be of any type as long as it can provide a shielding effect (effects such as magnetic flux stabilization and suppression of magnetic fields from peripheral components), and one example of such a shield is one made by appropriately molding a ferromagnetic material or the like.

[0028] Shield 33, bus bar 31, P-side bus bar 34, and N-side bus bar 35 are provided in lower frame 30 by insert molding. Furthermore, lower frame 30 has a plurality of screw holes 36 formed therein.

[0029] The upper frame 50 is made of, for example, resin. The upper frame 50 is disposed on the opposite side of the lower frame 430 with respect to the power semiconductor 40.

[0030] An upper frame opening 51 is formed in the upper frame 50 at a position corresponding to the main body of the power semiconductor 40 (a position that overlaps during assembly). A leaf spring 52 stands upright from a side surface of the upper frame opening 51 in a horizontal direction to the upper frame 50 and toward the inside of the upper frame opening 51. The upper frame opening 51 of this embodiment is also formed to extend to positions corresponding to the AC terminal 41, P terminal 42, and N terminal 43 of the power semiconductor 40 (positions that overlap during assembly).

[0031] Moreover, slits 53 are formed on the outer periphery of the upper frame 50 at positions where the shield 33 of the lower frame 30 penetrates through the thickness of the upper frame 50 during assembly. Also, screw holes 54 are formed in the upper frame 50.

[0032] A substrate (e.g., a gate drive substrate) (not shown) is disposed on the upper portion (opposite side of the power semiconductor 40) of the upper frame 50 in FIG. 1. A current sensor (e.g., an IC) is mounted within this substrate. The current sensor is disposed in a position that overlaps with the bus bar 31 during assembly (as viewed from the top-bottom direction in FIG. 1). Note that, like the upper frame 50, a slit is formed in the substrate at a position through which the shield 33 of the lower frame 30 passes during assembly.

[0033] The current sensor is mounted at a position on the board where it can detect the current of the bus bar 31. In the case of this embodiment, the current sensor is mounted on the surface of the board opposite the cooler 10 so as to be positioned opposite the corresponding bus bar 31 across the upper frame 50 and the board (opposing in the thickness direction) during assembly. The current sensor is also positioned between a pair of shields 33 during assembly. Any mode may be used for this current sensor as long as it can detect the current of the bus bar 31.

[0034] The cooler 10 has screw holes 11 formed at its four corners.

[0035] The upper frame 50, power semiconductors 40, insulating plate 20, and cooler 10 are fixed together with screws 60. That is, the cooler 10, insulating plate 20, lower frame 30, power semiconductors 40, upper frame 50, and substrate are stacked in this order from the bottom up, and the screws 60 are inserted through the screw holes 54 of the upper frame 50 and the screw holes 36 of the lower frame 30 and then attached to the screw holes 11 of the cooler 10.

[0036] Since the lower frame 30 has the lower frame opening 32 formed therein, the main body of the power semiconductor 40 penetrates the lower frame 30 during assembly, and the cooling surface of the power semiconductor 40 comes into contact with the cooler 10 via the insulating plate 20. Furthermore, since the upper frame 50 has the upper frame opening 51 and the leaf spring 52, the leaf spring 52 of the upper frame 50 applies pressure to bring the power semiconductor 40 into contact with the cooler 10 during assembly.

[0037] Moreover, the AC terminals 41 of the power semiconductors 40 are connected to the bus bars 31 of the lower frame 30 by screw connection using round holes in the AC terminals 41 and screw holes (not shown) in the bus bars 31. The P terminals 42 and the P-side bus bar 34, and the N terminals 43 and the N-side bus bar 35 are connected in the same manner.

[0038] Further, the leading ends of the shields 33 in the extending direction pass through the upper frame 50 and the substrate in the thickness direction via the slits 53 of the upper frame 50 and the slits of the substrate.

[0039] As shown in FIG. 1, by having the shields 33 penetrate the upper frame 50 and the substrate in the thickness direction, the current sensor is positioned between the pair of shields 33 and facing the corresponding bus bar 31 (facing each other in the thickness direction) with the upper frame 50 and the substrate in between.

[0040] Since the slits 53 are formed in the upper frame 50 and the board are formed with slits, the shield 33 of the lower frame 30 does not interfere with the upper frame 50 and the board during assembly, making assembly easier.

[0041] Bus bars 31 and shields 33 that connect to AC terminals 41 are insert-molded into lower frame 30, improving the accuracy of the positional relationship between shield 33 and bus bars 31.

[0042] According to the present invention, the power semiconductor 40 can be fixed to the cooler 10. In addition, the leaf springs 52 of the upper frame 50 apply pressure to the power semiconductor 40 to bring it into contact with the cooler 10, thereby improving the cooling capacity of the power semiconductor 40.

[0043] Moreover, since the current sensor can be surrounded by the shield 33, a shielding effect (such as magnetic flux stabilization and suppression of magnetic fields from peripheral components) can be obtained, and the detection accuracy of the current sensor can be improved.

[0044] In addition, since this embodiment has both the current sensor and the shield 33 as separate bodies, molding materials, etc. are not required, and the degree of freedom in the arrangement and support configuration of each of the current sensor and the shield 33 within the power conversion device is increased, and the degree of freedom in the arrangement and support configuration of the peripheral components is also increased.

[0045] Therefore, it is possible to simplify and miniaturize the configuration of the power conversion device, and to easily obtain the desired shielding effect. The above-mentioned simplification and miniaturization are expected to improve the assembly of the power conversion device (e.g., reducing the number of assembly steps and parts), and to reduce the weight and cost.

[0046] Any deviation in the position of the shield 33 adversely affects the detection accuracy of the current sensor. Therefore, when assembling the power conversion device, it is necessary to position the shield 33 with high accuracy. In this embodiment, the bus bar 31 and the shield 33 are insert-molded into the lower frame 30, and therefore the accuracy of current detection is improved by positioning the shield 33.

[0047] Furthermore, in this embodiment, since the insulation between the power semiconductor 40 and the cooler 10 is provided only by the insulating plate 20, the insulation between the power semiconductor 40 and the cooler 10 can be made compact.

[0048] Furthermore, by simply inserting the screws 60 through the screw holes 54 of the upper frame 50 and the screw holes 36 of the lower frame 30 and then attaching them to the screw holes 11 of the cooler 10, the power semiconductors 40 are fixed to the cooler 10 with pressure, improving the cooling capacity, and the shield 33 can be positioned with high precision, thereby contributing to a reduction in the assembly labor required for the power conversion device.

[0049] Although the present invention has been described in detail above only with respect to the specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention, and it is natural that such modifications and variations fall within the scope of the claims.

[0050] For example, in the embodiment, the power semiconductor 40 is described as a non-insulated type having an electrode on the back surface, but the power semiconductor 40 may be an insulated type as long as it has a cooling surface on the back surface. In the case of an insulated type, the metal on the back surface acts only as a cooling surface and not as an electrode. Also, when the power semiconductor 40 is an insulated type, the insulating plate 20 may be omitted.

[0051] Also, the power conversion device has been described as being configured such that all of the bus bars 31 that output three-phase AC power are provided with current sensors and shields, but the present invention is not limited to this. For example, it is sufficient if the power conversion device is configured to output multi-phase (e.g., two-phase) AC power, and if at least two of the bus bars 31 are provided with current sensors and shields (i.e., there are at least two combinations of corresponding bus bars 31, current sensors, and shields), it is possible to achieve the same effects as the present embodiment. [Explanation of symbols]

[0052] 10...Cooler 11...Screw hole 20...Insulating plate 30…Lower frame 31…Busbar 32…Lower frame opening 33…Shield 34…P conductor 35...N conductor 36…Screw hole 40…Power semiconductors 41…AC terminal 42...P terminal 43…N terminal 50…Upper frame 51…Upper frame opening 52…Leaf spring 53...Slit 54…Screw hole 60…Screw

Claims

1. A power conversion device including a power semiconductor, A cooler that cools the power semiconductor; The power semiconductor has a cooling surface on a surface of a main body facing the cooler and has an AC terminal; a lower frame including a bus bar provided between the cooler and the power semiconductor and connected to the AC terminal, a pair of shields erected from both side edges of the bus bar toward the power semiconductor, and a lower frame opening portion cut out at a position that will overlap with the main body portion of the power semiconductor during assembly; an upper frame provided on the opposite side of the cooler with respect to the power semiconductor, the upper frame having a slit formed at a position through which the shield passes during assembly, an upper frame opening cut out at a position that overlaps with the main body of the power semiconductor and the AC terminal during assembly, and a leaf spring erected from a side surface of the upper frame opening toward the inside of the upper frame opening; a substrate disposed on an opposite side of the power semiconductor with respect to the upper frame, the substrate having a current sensor mounted at a position where the current sensor overlaps with the bus bar during assembly; Equipped with The power semiconductor is fixed to the cooler while being sandwiched between the upper frame and the lower frame.

2. an insulating plate disposed between the lower frame and the cooler; 2. The power conversion device according to claim 1, wherein the power semiconductor is of a non-insulated type.

3. 2. The power conversion device according to claim 1, wherein the bus bar and the shield are insert-molded into the lower frame.

4. Outputs multiple phase AC power, 2. The power conversion device according to claim 1, further comprising the current sensor and the shield corresponding to the bus bar of each phase.

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