Power modules, power converters, drive systems, heat pump systems

Abstract

It accurately detects the current flowing through the switching elements housed within the casing. [Solution] The first conductive path (51) is housed within the casing (20) and connects the first terminal (31) and the second terminal (32). The auxiliary conductive path (55) is housed within the casing (20), one end of which is connected to the first auxiliary terminal (41), and is electrically connected in parallel with the first conductive path (51). The first switching element (SW1) and the second switching element (SW2) are provided in series in the first conductive path (51). The capacitor (C1) is provided in the auxiliary conductive path (55).

Description

Technical Field

[0001] The present disclosure relates to a power module, a power conversion device, a drive system, and a heat pump system.

Background Art

[0002] Patent Document 1 discloses a semiconductor device. The semiconductor device includes a semiconductor chip, a first external terminal, a second external terminal, a capacitor, a sealing member, and a case.

[0003] The semiconductor chip is a transistor. The first external terminal and the second external terminal are electrically connected to the semiconductor chip. One end of the capacitor is connected to the first external terminal, and the other end of the capacitor is connected to the second external terminal. The sealing member seals the semiconductor chip. The capacitor is provided inside the sealing member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the semiconductor device of Patent Document 1, since the semiconductor chip and the capacitor are electrically connected in parallel between the first external terminal and the second external terminal, when a wiring is connected to the first external terminal or the second external terminal outside the case, the current flowing through the wiring includes not only the current flowing through the semiconductor chip but also the current flowing through the capacitor. Therefore, it is difficult to accurately detect the current flowing through the semiconductor chip because the current flowing through the semiconductor chip cannot be detected so that the "current flowing through the capacitor" is not included outside the case.

Means for Solving the Problems

[0006] A first aspect of this disclosure relates to a power module, which is a power module Casing (20) and The casing (20) is provided with a first terminal (31), a second terminal (32), and a first auxiliary terminal (41) which are exposed to the outside of the casing (20), A first conductive path (51) is housed within the casing (20) and connects the first terminal (31) and the second terminal (32), An auxiliary conductive path (55) is housed within the casing (20), one end of which is connected to the first auxiliary terminal (41), and which can be electrically connected in parallel with the first conductive path (51), A first switching element (SW1) and a second switching element (SW2) are provided in series in the first conductive path (51), The system includes a capacitor (C1) provided in the auxiliary conductive path (55).

[0007] In the first embodiment, by connecting one end of the auxiliary conductive path (55) to a first auxiliary terminal (41) that is not connected to the first terminal (31) and second terminal (32) of the first conductive path (51), it is possible to ensure that the current flowing through the auxiliary conductive path (55) is not included in the current flowing through the wiring when wiring is connected to the first terminal (31) or second terminal (32) outside the casing (20). As a result, the current flowing through the first switching element (SW1) and the second switching element (SW2) provided on the first conductive path (51) can be accurately detected based on the current flowing through the wiring connected to the first terminal (31) or second terminal (32) outside the casing (20).

[0008] A second aspect of this disclosure relates to the power module of the first aspect, The straight-line distance between the terminal closer to the first auxiliary terminal (41) and the first auxiliary terminal (41) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32). It is a power module.

[0009] In the second embodiment, the auxiliary conductive path (55) can be routed within the casing (20) such that it passes close to the first conductive path (51).

[0010] A third aspect of this disclosure relates to a power module of the first or second aspect, The auxiliary conductive path (55) has a parallel portion (56) which is a portion that is parallel to a part or all of the first conductive path (51) at a predetermined distance (D1). It is a power module.

[0011] In the third embodiment, the auxiliary conductive path (55) and the first conductive path (51) can be brought closer to each other such that part or all of the auxiliary conductive path (55) and part or all of the first conductive path (51) are parallel at a predetermined distance (D1).

[0012] A fourth aspect of this disclosure relates to the power module of the third aspect, The predetermined interval (D1) is 2 mm or less. It is a power module.

[0013] In the fourth embodiment, the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55) makes it easier to obtain the effect of reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55).

[0014] A fifth aspect of this disclosure relates to a power module of the third or fourth aspect, The length (L1) of the parallel portion (56) of the auxiliary conductive path (55) is longer than the length (W0) of the auxiliary conductive path (55) in the width direction perpendicular to the direction along the auxiliary conductive path (55). It is a power module.

[0015] In the fifth embodiment, the parallel portion (56) of the auxiliary conductive path (55) can be effectively formed.

[0016] In the sixth aspect of the present disclosure, in the power module according to the third or fourth aspect, The ratio of the length (L1) of the parallel portion (56) of the auxiliary conductive path (55) to the total length (L0) of the auxiliary conductive path (55) in a direction orthogonal to the direction of the predetermined interval (D1) is 65% or more. It is a power module.

[0017] In the sixth aspect, it is possible to easily obtain the effect of reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55) due to the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55).

[0018] In the seventh aspect of the present disclosure, in any one of the power modules according to the first to sixth aspects, A second conductive path (52) that can be electrically connected in parallel with the first conductive path (51), A third switching element (SW3) and a fourth switching element (SW4) provided in series in the second conductive path (52), The auxiliary conductive path (55) is disposed between the first conductive path (51) and the second conductive path (52). It is a power module.

[0019] In the seventh aspect, one auxiliary conductive path (55) can be used as both an auxiliary conductive path disposed near the first conductive path (51) and an auxiliary conductive path disposed near the second conductive path (52). Thereby, the cost for providing the auxiliary conductive path (55) can be reduced compared to the case where one auxiliary conductive path (55) is provided individually for each of the first conductive path (51) and the second conductive path (52).

[0020] The eighth aspect of the present disclosure relates to a power conversion device including any one of the power modules according to the first to seventh aspects.

[0021] A ninth aspect of the present disclosure relates to a drive system comprising a power converter according to the eighth aspect and a motor (65) driven by power output from the power converter.

[0022] A tenth aspect of the present disclosure relates to a heat pump system comprising a power converter according to the eighth aspect, a compressor (71) having a motor (65) driven by power output from the power converter, and a compression mechanism (71a) driven by the motor (65). [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a circuit diagram illustrating the configuration of a power module according to an embodiment. [Figure 2] Figure 2 is a plan view illustrating the specific configuration of the power module according to the embodiment. [Figure 3] Figure 3 is a cross-sectional view illustrating the specific configuration of the power module of the embodiment, and corresponds to the cross-section along line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view illustrating the specific configuration of the power module of the embodiment, and corresponds to the cross-section along line IV-IV in Figure 2. [Figure 5] Figure 5 is a schematic diagram illustrating the details of the power module of the embodiment. [Figure 6] Figure 6 is a graph illustrating the relationship between a predetermined spacing in the parallel section of an auxiliary conductive path and various inductances. [Figure 7] Figure 7 is a graph illustrating the relationship between a predetermined spacing and differential inductance in the parallel section of an auxiliary conductive path. [Figure 8] Figure 8 is a graph illustrating the relationship between the parallelism of the auxiliary conductive path and the differential inductance. [Figure 9] Figure 9 is a circuit diagram illustrating a configuration for testing the power module of the embodiment. [Figure 10] Figure 10 is a circuit diagram illustrating a configuration for implementing the power module of the embodiment. [Figure 11] Figure 11 is a circuit diagram illustrating the configuration of a power module in a modified example of the embodiment 1. [Figure 12] Figure 12 is a plan view illustrating a specific configuration of a power module according to a modified example of the embodiment 1. [Figure 13] Figure 13 is a circuit diagram illustrating the configuration of a power module in a modified example of the embodiment 2. [Figure 14] Figure 14 is a circuit diagram illustrating the configuration of a power module in a modified example of the embodiment 3. [Figure 15] Figure 15 is a circuit diagram illustrating the configuration of a power module in a modified example of the embodiment 4. [Figure 16] Figure 16 is a circuit diagram illustrating the configuration of a power module in modified example 5 of the embodiment. [Figure 17] Figure 17 is a piping diagram illustrating the configuration of a heat pump system, including the drive system. [Figure 18] Figure 18 is a circuit diagram showing a modified example of the auxiliary conductive path. [Figure 19] Figure 19 is a circuit diagram showing another modified example of the auxiliary conductive path. [Modes for carrying out the invention]

[0024] The embodiments will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, this disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of ​​this disclosure. Since the drawings are for conceptual explanation of this disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

[0025] (Embodiment) Figure 1 illustrates the configuration of a power module (10) according to an embodiment of the present disclosure. The power module (10) comprises a casing (20), a first terminal (31), a second terminal (32), a first auxiliary terminal (41), a second auxiliary terminal (42), and a first output terminal (45).

[0026] The casing (20) is provided with a first terminal (31), a second terminal (32), a first auxiliary terminal (41), a second auxiliary terminal (42), and a first output terminal (45). The components of the power module (10) are also housed inside the casing (20).

[0027] The power module (10) also includes a first conductive path (51), an auxiliary conductive path (55), a first switching element (SW1), a second switching element (SW2), and a capacitor (C1). These are examples of components of the power module (10) housed in the casing (20). The power module (10) can constitute a half-bridge circuit.

[0028] The first conductive path (51) connects the first terminal (31) and the second terminal (32). Specifically, one end of the first conductive path (51) is connected to the first terminal (31), and the other end of the first conductive path (51) is connected to the second terminal (32).

[0029] One end of the auxiliary conductive path (55) is connected to the first auxiliary terminal (41). The auxiliary conductive path (55) is configured to be electrically connected in parallel with the first conductive path (51). In this example, the other end of the auxiliary conductive path (55) is connected to the second auxiliary terminal (42). By electrically connecting the first terminal (31) to the first auxiliary terminal (41) and the second terminal (32) to the second auxiliary terminal (42), the auxiliary conductive path (55) is electrically connected in parallel with the first conductive path (51). The auxiliary conductive path (55) is also arranged along the first conductive path (51) at a predetermined distance from it.

[0030] The first switching element (SW1) and the second switching element (SW2) are arranged in series in the first conductive path (51). In this example, the first switching element (SW1) and the second switching element (SW2) are composed of transistors. Examples of transistors include field-effect transistors (FETs) and insulated-gate transistors (IGBTs).

[0031] Specifically, one end (e.g., drain) of the first switching element (SW1) is connected to the first terminal (31). The other end (e.g., source) of the first switching element (SW1) is connected to one end (e.g., drain) of the second switching element (SW2). The other end (e.g., source) of the second switching element (SW2) is connected to the second terminal (32). Each of the first switching element (SW1) and the second switching element (SW2) has a control terminal (e.g., gate, not shown) that switches on or off depending on the voltage applied to the control terminal. In this example, the first output terminal (45) is connected to the connection point between the first switching element (SW1) and the second switching element (SW2).

[0032] Capacitor (C1) is provided in the auxiliary conductive path (55). Examples of capacitors (C1) include electrolytic capacitors, film capacitors, and ceramic capacitors. Capacitor (C1) is used as a snubber capacitor. A snubber capacitor is a capacitor provided to suppress the generation of surge voltage in the conductive path.

[0033] [Specific configuration of the power module] Next, the specific configuration of the power module (10) will be described with reference to Figures 2 to 4. Note that in Figure 2, the parts of the casing (20) other than the bottom surface (heat sink (22) described later) are not shown. Figure 3 illustrates a cross-section of the power module (10) along line III-III in Figure 2, and Figure 4 illustrates a cross-section of the power module (10) along line IV-IV in Figure 2.

[0034] The power module (10) includes a substrate (21). The substrate (21) is made of an insulating material such as epoxy resin and is formed in the shape of a rectangular flat plate. Conductive regions (wiring layers) that constitute conductive paths are formed on the surface of the substrate (21).

[0035] The power module (10) also includes bonding wires (25). The bonding wires (25) electrically connect a conductive region formed on the formation surface of the substrate (21) with a component (for example, a first switching element (SW1)) placed on the formation surface of the substrate (21).

[0036] The casing (20) is formed in the shape of a rectangular box. The bottom of the casing (20) is made up of a heat sink (22). The heat sink (22) is made of a heat transfer material such as aluminum and is formed in the shape of a thick rectangular plate. A substrate (21) is attached to the side of the heat sink (22) opposite to the heat dissipation surface.

[0037] As shown in Figure 2, the first conductive path (51) is composed of a first conductive region (51a), a second conductive region (51b), and a third conductive region (51c). The auxiliary conductive path (55) is composed of a first auxiliary conductive region (55a) and a second auxiliary conductive region (55b).

[0038] In this example, the first conductive region (51a), the second conductive region (51b), and the third conductive region (51c) are arranged in a row on the substrate (21). Similarly, the first auxiliary conductive region (55a) and the second auxiliary conductive region (55b) are arranged in a row on the substrate (21). The direction in which the first auxiliary conductive region (55a) and the second auxiliary conductive region (55b) are arranged is the same as the direction in which the first conductive region (51a), the second conductive region (51b), and the third conductive region (51c) are arranged. The first auxiliary conductive region (55a) and the second auxiliary conductive region (55b) face the first conductive region (51a), the second conductive region (51b), and the third conductive region (51c) in a direction perpendicular to the above-mentioned direction of arrangement, with a predetermined gap between them.

[0039] The first conductive region (51a) is where the first terminal (31) and the first switching element (SW1) are located. The second conductive region (51b) is where the first output terminal (45) and the second switching element (SW2) are located. The third conductive region (51c) is where the second terminal (32) is located. The first auxiliary conductive region (55a) is where the first auxiliary terminal (41) is located. The second auxiliary conductive region (55b) is where the second auxiliary terminal (42) is located.

[0040] As shown in Figures 3 and 4, the first terminal (31) is exposed to the outside of the casing (20). In this example, the first terminal (31) is formed in the shape of a rod protruding from the casing (20). The first terminal (31) is also provided in the first conductive region (51a) and is electrically connected to the first conductive region (51a). The configuration of the second terminal (32), the first auxiliary terminal (41), the second auxiliary terminal (42), and the first output terminal (45) is the same as the configuration of the first terminal (31).

[0041] As shown in Figure 2, in this example, the straight-line distance between the terminal closer to the first auxiliary terminal (41) (the first terminal (31) in the example of Figure 2) and the first auxiliary terminal (41) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32). Similarly, the straight-line distance between the terminal closer to the second auxiliary terminal (42) (the second terminal (32) in the example of Figure 2) and the second auxiliary terminal (42) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32).

[0042] As shown in Figure 3, the first switching element (SW1) is electrically connected to the first conductive region (51a) by being placed in the first conductive region (51a), and is electrically connected to the second conductive region (51b) by being connected to the second conductive region (51b) by a bonding wire (25). For example, an electrode that will be one end of the first switching element (SW1) (e.g., the drain) is provided on the lower surface (the surface in contact with the conductive region) of the semiconductor chip constituting the first switching element (SW1), and an electrode that will be the other end of the first switching element (SW1) (e.g., the source) is provided on the upper surface (the surface opposite to the surface in contact with the conductive region) of the semiconductor chip.

[0043] The second switching element (SW2) is provided in the second conductive region (51b), thereby electrically connecting it to the second conductive region (51b), and is connected to the third conductive region (51c) by a bonding wire (25), thereby electrically connecting it to the third conductive region (51c). For example, the configuration of the semiconductor chip constituting the second switching element (SW2) is the same as the configuration of the semiconductor chip constituting the first switching element (SW1).

[0044] The capacitor (C1) is positioned to straddle the first auxiliary conductive region (55a) and the second auxiliary conductive region (55b). One electrode constituting one end of the capacitor (C1) is provided in the first auxiliary conductive region (55a), thereby electrically connecting it to the first auxiliary conductive region (55a). The other electrode constituting the other end of the capacitor (C1) is provided in the second auxiliary conductive region (55b), thereby electrically connecting it to the second auxiliary conductive region (55b).

[0045] [Details of the power module] Next, the details of the power module (10) will be explained with reference to Figures 5 to 8. In Figure 5, for the sake of explanation, the conductive regions constituting the first conductive path (51) and the conductive regions constituting the auxiliary conductive path (55) are shown in a simplified manner.

[0046] As shown in Figure 5, the auxiliary conductive path (55) has a parallel portion (56) which is a portion that is parallel to a part or all of the first conductive path (51) at a predetermined distance (D1). In this example, the predetermined distance (D1) is 2 mm or less. The parallel portion (56) may be a part of the auxiliary conductive path (55) or it may be the entirety of the auxiliary conductive path (55).

[0047] Furthermore, the length (L1) of the parallel portion (56) of the auxiliary conductive path (55) is longer than the length (W0) of the auxiliary conductive path (55) in the width direction perpendicular to the direction along the auxiliary conductive path (55).

[0048] Furthermore, the ratio of the length (L1) of the parallel portion (56) of the auxiliary conductive path (55) to the total length (L0) of the auxiliary conductive path (55) in the direction perpendicular to the predetermined interval (D1) is 65% or more. Hereafter, the above ratio will be referred to as "parallelism".

[0049] <Prescribed interval> Next, with reference to Figure 6, the findings obtained regarding the "predetermined interval (D1)" in the parallel portion (56) of the auxiliary conductive path (55) will be explained. As a result of diligent research, the inventors of this application have found that by setting the predetermined interval (D1) to "2 mm or less", the effect of "reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55) due to the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)" becomes easier to obtain.

[0050] Figure 6 illustrates the relationship between the "predetermined interval (D1)", the "self-inductance of the first conductive path (51) and the auxiliary conductive path (55)", and the "mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)". In the example in Figure 6, the thickness of the conductive region constituting the first conductive path (51) and the thickness of the conductive region constituting the auxiliary conductive path (55) are the same, and the self-inductance of the first conductive path (51) and the self-inductance of the auxiliary conductive path (55) are the same.

[0051] As shown in Figure 6, as the predetermined interval (D1) decreases, the "self-inductance of the first conductive path (51) and the auxiliary conductive path (55)" gradually decreases, while the "mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)" gradually increases.

[0052] In the example in Figure 6, the area enclosed by the dashed circle in Figure 6 is the inflection point in the curve showing the change in mutual inductance. In other words, the increase in mutual inductance in response to a decrease in the predetermined interval (D1) is steeper when the predetermined interval (D1) is 2 mm or less than when the predetermined interval (D1) is longer than 2 mm. Also, the decrease in self-inductance in response to a decrease in the predetermined interval (D1) is steeper when the predetermined interval (D1) is 2 mm or less than when the predetermined interval (D1) is longer than 2 mm.

[0053] Therefore, by setting the predetermined interval (D1) to "2 mm or less," the effect of "reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55) due to the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)" becomes easier to achieve.

[0054] <Parallelism of auxiliary conductive paths (55)> Next, the parallelism of the auxiliary conductive path (55) will be explained with reference to Figures 7 and 8. As a result of diligent research, the inventors of this application have found that by setting the parallelism of the auxiliary conductive path (55) to "65% or more", the effect of "reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55) due to the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)" becomes easier to obtain.

[0055] Figure 7 illustrates the relationship between the "predetermined interval (D1)" and the "differential inductance of the auxiliary conduction path (55)". The differential inductance of the auxiliary conduction path (55) is the inductance obtained by subtracting the "mutual inductance between the first conduction path (51) and the auxiliary conduction path (55)" from the "self-inductance of the auxiliary conduction path (55)".

[0056] In the example shown in Figure 7, the goal is to obtain an effect equivalent to the "reduction of self-inductance" effect obtained when the predetermined interval (D1) is "2 mm or less". To achieve this, the threshold (Lth) used as the criterion for determining whether or not the "reduction of self-inductance" effect is present is set to "the differential inductance obtained when the predetermined interval (D1) is "2 mm or less".

[0057] Figure 8 illustrates the relationship between the "parallelism of the auxiliary conductive path (55)" and the "differential inductance of the auxiliary conductive path (55)". In the example in Figure 8, for ease of calculation, the predetermined interval (D1) is set to an ideal interval (e.g., 10 μm). This "ideal interval" corresponds to the predetermined interval (D1) at which the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55) can cancel out the "self-inductance of the auxiliary conductive path (55)".

[0058] As shown in Figure 8, as the parallelism of the auxiliary conductive path (55) gradually decreases from "100%", the differential inductance of the auxiliary conductive path (55) gradually increases. The parallelism of the auxiliary conductive path (55) is "65%" when the differential inductance of the auxiliary conductive path (55) reaches the threshold (Lth).

[0059] Therefore, by setting the parallelism of the auxiliary conductive path (55) to "65% or more," the effect of "reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55) due to the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55)" becomes easier to achieve.

[0060] [Structure for the exam] As shown in Figure 9, a test device (90) is connected to the power module (10) in order to test the power module (10). The test device (90) includes a first test line (91), a second test line (92), a test power supply (95), and an ammeter (96).

[0061] The first test line (91) connects the positive terminal of the test power supply (95) to the first terminal (31) and the first auxiliary terminal (41) of the power module (10). Specifically, the first test line (91) has a first main line section (91a), a first branch line section (91b), and a first auxiliary branch line section (91c). One end of the first main line section (91a) is connected to the positive terminal of the test power supply (95). The first branch line section (91b) connects the first terminal (31) to the other end of the first main line section (91a). The first auxiliary branch line section (91c) connects the first auxiliary terminal (41) to the other end of the first main line section (91a).

[0062] The second test line (92) connects the negative terminal of the test power supply (95) to the second terminal (32) and the second auxiliary terminal (42) of the power module (10). Specifically, the second test line (92) has a second main line section (92a), a second branch line section (92b), and a second auxiliary branch line section (92c). One end of the second main line section (92a) is connected to the negative terminal of the test power supply (95). The second branch line section (92b) connects the second terminal (32) to the other end of the second main line section (92a). The second auxiliary branch line section (92c) connects the second auxiliary terminal (42) to the other end of the second main line section (92a).

[0063] The first branch section (91b) and the second branch section (92b) are connected in series with respect to the first conductive path (51). Therefore, the current flowing through the first branch section (91b) and the second branch section (92b) is the same as the current flowing through the first conductive path (51). This current does not include the current flowing through the auxiliary conductive path (55).

[0064] The first auxiliary branch section (91c) and the second auxiliary branch section (92c) are connected in series with respect to the auxiliary conductive path (55). Therefore, the current flowing through the first auxiliary branch section (91c) and the second auxiliary branch section (92c) is the same as the current flowing through the auxiliary conductive path (55). This current does not include the "first conductive path (51)".

[0065] The ammeter (96) is installed on the first branch line (91b) of the first test line (91). This allows the ammeter (96) to detect the current flowing through the first switching element (SW1) and the second switching element (SW2) installed in the first conductive path (51).

[0066] The above configuration for testing the power module (10) is merely an example. The connection between the power module (10) and the test device (90) may be changed as appropriate depending on the purpose of testing the power module (10).

[0067] [Configuration for implementation] As shown in Figure 10, when the power module (10) is implemented as a "half-bridge circuit," the first terminal (31), the first auxiliary terminal (41), and the positive terminal of the DC power supply (15) are connected to the positive terminal wire (11). The second terminal (32), the second auxiliary terminal (42), and the negative terminal of the DC power supply (15) are connected to the negative terminal wire (12). The load (16) is connected between the first output terminal (45) and the negative terminal wire (12). The negative terminal wire (12) is grounded.

[0068] In this way, by electrically connecting the first terminal (31) and the first auxiliary terminal (41), and by electrically connecting the second terminal (32) and the second auxiliary terminal (42), the auxiliary conductive path (55) is electrically connected in parallel with the first conductive path (51). This allows the capacitor (C1) provided in the auxiliary conductive path (55) to function as a "snubber capacitor".

[0069] The above configuration for implementing the power module (10) is merely an example. Depending on the implementation of the power module (10), the connections between the power module (10) and other components (such as the load (16)) may be appropriately modified.

[0070] [Effects of the Embodiment] As described above, in the power module (10) of this embodiment, the first conductive path (51) is housed within the casing (20) and connects the first terminal (31) and the second terminal (32). The auxiliary conductive path (55) is housed within the casing (20), one end of which is connected to the first auxiliary terminal (41), and is electrically connected in parallel with the first conductive path (51). The first switching element (SW1) and the second switching element (SW2) are provided in series in the first conductive path (51). The capacitor (C1) is provided in the auxiliary conductive path (55).

[0071] In the above configuration, by connecting the first conductive path (51) to the first terminal (31) and the second terminal (32), if a wire is connected to the first terminal (31) or the second terminal (32) outside the casing (20), the "current flowing through the first conductive path (51)" can be passed through that wire.

[0072] Furthermore, in the above configuration, by connecting one end of the auxiliary conductive path (55) to a first auxiliary terminal (41) that is not to the first terminal (31) or second terminal (32) to which the first conductive path (51) is connected, it is possible to ensure that the current flowing through the auxiliary conductive path (55) is not included in the current flowing through the wiring when wiring is connected to the first terminal (31) or second terminal (32) outside the casing (20).

[0073] As a result, the current flowing through the first switching element (SW1) and the second switching element (SW2) provided in the first conductive path (51) can be accurately detected based on the current flowing through the wiring connected to the first terminal (31) or the second terminal (32) outside the casing (20).

[0074] Furthermore, by providing an auxiliary conductive path (55) together with the first conductive path (51) within the casing (20), the auxiliary conductive path (55) can be positioned close to the first conductive path (51). This allows the self-inductance of each of the first conductive path (51) and the auxiliary conductive path (55) to be reduced by the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55). As a result, the switching speed of the first switching element (SW1) and the second switching element (SW2) can be increased. Surge voltage can also be suppressed.

[0075] Furthermore, by housing the capacitor (C1) together with the first switching element (SW1) and the second switching element (SW2) within the casing (20), the heat dissipation components (e.g., heat sinks) for the first switching element (SW1) and the second switching element can also be used for heat dissipation of the capacitor (C1). This promotes heat dissipation of the capacitor (C1).

[0076] Furthermore, in the power module (10) of the embodiment, the straight-line distance between the terminal closer to the first auxiliary terminal (41) and the first auxiliary terminal (41) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32).

[0077] In the above configuration, the auxiliary conductive path (55) can be routed within the casing (20) so that it passes close to the first conductive path (51).

[0078] Furthermore, in the power module (10) of the embodiment, the auxiliary conductive path (55) has a parallel portion (56) which is a portion that is parallel to a part or all of the first conductive path (51) at a predetermined distance (D1).

[0079] In the above configuration, the auxiliary conductive path (55) and the first conductive path (51) can be brought closer to each other so that part or all of the auxiliary conductive path (55) and part or all of the first conductive path (51) are parallel at a predetermined distance (D1).

[0080] Furthermore, in the power module (10) of the embodiment, the predetermined interval (D1) is 2 mm or less.

[0081] In the above configuration, the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55) makes it easier to obtain the effect of reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55).

[0082] Furthermore, in the power module (10) of the embodiment, the length (L1) of the parallel portion (56) of the auxiliary conductive path (55) is longer than the length (W0) of the auxiliary conductive path (55) in the width direction perpendicular to the direction along the auxiliary conductive path (55).

[0083] In the above configuration, the parallel portion (56) of the auxiliary conductive path (55) can be effectively formed.

[0084] Furthermore, in the power module (10) of the embodiment, the ratio of the length (L1) of the parallel portion (56) of the auxiliary conductive path (55) to the total length (L0) of the auxiliary conductive path (55) in a direction perpendicular to the direction of the predetermined interval (D1) is 65% or more.

[0085] In the above configuration, the mutual inductance between the first conductive path (51) and the auxiliary conductive path (55) makes it easier to obtain the effect of reducing the self-inductance in each of the first conductive path (51) and the auxiliary conductive path (55).

[0086] (Modification of Embodiment 1) Figure 11 illustrates the configuration of a power module (10) in the first modified embodiment. In the first modified embodiment, the power module (10) includes, in addition to the configuration of the power module (10) shown in Figure 1, a second conductive path (52), a third switching element (SW3), and a fourth switching element (SW4). The second conductive path (52), the third switching element (SW3), and the fourth switching element (SW4) are housed in a casing (20).

[0087] In this example, the power module (10) includes a third terminal (33), a fourth terminal (34), and a second output terminal (46). The third terminal (33), the fourth terminal (34), and the second output terminal (46) are provided in the casing (20). The configuration of the third terminal (33) and the fourth terminal (34) is the same as the configuration of the first terminal (31). The configuration of the second output terminal (46) is the same as the configuration of the first output terminal (45). The power module (10) can be configured as a full-bridge circuit.

[0088] The second conductive path (52) is configured to be electrically connected in parallel with the first conductive path (51). In this example, the second conductive path (52) connects the third terminal (33) and the fourth terminal (34). By electrically connecting the first terminal (31) and the third terminal (33), and also by electrically connecting the second terminal (32) and the fourth terminal (34), the second conductive path (52) is electrically connected in parallel with the first conductive path (51).

[0089] The third switching element (SW3) and the fourth switching element (SW4) are provided in series in the second conductive path (52). The configuration of the third switching element (SW3) and the fourth switching element (SW4) is the same as that of the first switching element (SW1) and the second switching element (SW2). The power module (10) includes a switching leg composed of the first switching element (SW1) and the second switching element (SW2), and a switching leg composed of the third switching element (SW3) and the fourth switching element (SW4).

[0090] Furthermore, in the modified embodiment 1, the auxiliary conductive path (55) is arranged between the first conductive path (51) and the second conductive path (52).

[0091] [Specific configuration of the power module] As shown in Figure 12, in the modified embodiment 1, the second conductive path (52) is composed of a first conductive region (52a), a second conductive region (52b), and a third conductive region (52c).

[0092] In this example, the first conductive region (52a), the second conductive region (52b), and the third conductive region (52c) of the second conductive path (52) are arranged in a line on the substrate (21). The first conductive region (52a), the second conductive region (52b), and the third conductive region (52c) of the second conductive path (52) are positioned opposite the first auxiliary conductive region (55a) and the second auxiliary conductive region (55b) at a predetermined distance in a direction perpendicular to the direction of alignment described above.

[0093] The first conductive region (52a) contains the third terminal (33) and the third switching element (SW3). The second conductive region (52b) contains the second output terminal (46) and the fourth switching element (SW4). The third conductive region (52c) contains the fourth terminal (34).

[0094] The third switching element (SW3) is provided in the first conductive region (52a), thereby electrically connecting it to the first conductive region (52a), and is connected to the second conductive region (52b) by a bonding wire (25), thereby electrically connecting it to the second conductive region (52b).

[0095] The fourth switching element (SW4) is provided in the second conductive region (52b), thereby electrically connecting it to the second conductive region (52b), and is connected to the third conductive region (52c) by a bonding wire (25), thereby electrically connecting it to the third conductive region (52c).

[0096] The auxiliary conductive regions (55a, 55b) constituting the auxiliary conductive path (55) are arranged between the three conductive regions (51a, 51b, 51c) constituting the first conductive path (51) and the three conductive regions (52a, 52b, 52c) constituting the second conductive path (52).

[0097] The other configurations of the power module (10) in the modified example 1 of the embodiment are the same as those of the power module (10) in the embodiment.

[0098] [Effects of Modified Example 1 of the Embodiment] As described above, in the power module (10) of the modified embodiment 1, the second conductive path (52) can be electrically connected in parallel with the first conductive path (51). The third switching element (SW3) and the fourth switching element (SW4) are provided in series in the second conductive path (52). The auxiliary conductive path (55) is arranged between the first conductive path (51) and the second conductive path (52).

[0099] In the above configuration, one auxiliary conductive path (55) can be used to serve both as an auxiliary conductive path located near the first conductive path (51) and as an auxiliary conductive path located near the second conductive path (52). This reduces the cost of providing the auxiliary conductive paths (55) compared to providing one auxiliary conductive path (55) separately for each of the first conductive path (51) and the second conductive path (52).

[0100] (Modified embodiment 2) Figure 13 illustrates the configuration of the power module (10) in a modified example of the embodiment 2. In the modified example of the embodiment 2, the third terminal (33) and the fourth terminal (34) shown in Figure 11 are omitted. One end of the second conductive path (52) is connected to the first terminal (31), and the other end of the second conductive path (52) is connected to the second terminal (32). In this way, the second conductive path (52) may be configured to always be electrically connected in parallel with the first conductive path (51).

[0101] The other configurations of the power module (10) in the modified example 2 of the embodiment are the same as those of the power module (10) in the modified example 1 of the embodiment.

[0102] (Modification of Embodiment 3) Figure 14 illustrates the configuration of the power module (10) in the third modified embodiment. In the third modified embodiment, the power module (10) includes, in addition to the configuration of the power module (10) shown in Figure 11, a third conductive path (53), a fifth terminal (35), a sixth terminal (36), a third output terminal (47), a fifth switching element (SW5), and a sixth switching element (SW6). The power module (10) can constitute a three-phase inverter circuit.

[0103] The third conductive path (53) is configured to be electrically connected in parallel with the first conductive path (51). In this example, the third conductive path (53) connects the fifth terminal (35) and the sixth terminal (36). By electrically connecting the first terminal (31) and the fifth terminal (35), and also by electrically connecting the second terminal (32) and the sixth terminal (36), the third conductive path (53) is electrically connected in parallel with the first conductive path (51).

[0104] The configuration of the fifth terminal (35) and the sixth terminal (36) is the same as the configuration of the first terminal (31). The configuration of the third output terminal (47) is the same as the configuration of the first output terminal (45).

[0105] The fifth switching element (SW5) and the sixth switching element (SW6) are provided in series in the third conductive path (53). The configuration of the fifth switching element (SW5) and the sixth switching element (SW6) is the same as that of the first switching element (SW1) and the second switching element (SW2). The power module (10) includes a switching leg composed of the first switching element (SW1) and the second switching element (SW2), a switching leg composed of the third switching element (SW3) and the fourth switching element (SW4), and a switching leg composed of the fifth switching element (SW5) and the sixth switching element (SW6).

[0106] Furthermore, in the third modified embodiment, the auxiliary conductive path (55) is positioned next to the third conductive path (53). Thus, the auxiliary conductive path (55) does not have to be positioned between multiple conductive paths.

[0107] The other configurations of the power module (10) in the modified example 3 of the embodiment are the same as those of the power module (10) in the modified example 1 of the embodiment.

[0108] Furthermore, similar to the 2nd modified embodiment, the third terminal (33), fourth terminal (34), fifth terminal (35), and sixth terminal (36) shown in Figure 14 may be omitted. In this case, one end of the second conductive path (52) and the third conductive path (53) is connected to the first terminal (31), and the other end of the second conductive path (52) and the third conductive path (53) is connected to the second terminal (32). In this way, the third conductive path (53) may be configured to always be electrically connected in parallel with the first conductive path (51).

[0109] (Modification of Embodiment 4) Figure 15 illustrates the configuration of the power module (10) in the fourth modified embodiment. In the fourth modified embodiment, the power module (10) has three auxiliary conductive paths (55) corresponding to three conductive paths (51, 52, 53), instead of the single auxiliary conductive path (55) shown in Figure 14.

[0110] An auxiliary conductive path (55) corresponding to the first conductive path (51) is provided next to the first conductive path (51). An auxiliary conductive path (55) corresponding to the second conductive path (52) is provided next to the second conductive path (52). An auxiliary conductive path (55) corresponding to the third conductive path (53) is provided next to the third conductive path (53). In this way, in the power module (10), multiple auxiliary conductive paths (55) corresponding to multiple conductive paths (51, 52, 53) may be provided.

[0111] The other configurations of the power module (10) in the modified example 4 of the embodiment are the same as those of the power module (10) in the modified example 3 of the embodiment.

[0112] Furthermore, similar to the 2nd modified embodiment, the third terminal (33), fourth terminal (34), fifth terminal (35), and sixth terminal (36) shown in Figure 15 may be omitted.

[0113] (Modification of Embodiment 5) Figure 16 illustrates the configuration of the power module (10) in the fifth modified embodiment. In the fifth modified embodiment, the power module (10) has two auxiliary conductive paths (55) positioned between the three conductive paths (51, 52, 53), instead of the single auxiliary conductive path (55) shown in Figure 14.

[0114] One of the two auxiliary conductive paths (55) is positioned between the first conductive path (51) and the second conductive path (52), and the remaining auxiliary conductive path (55) is positioned between the second conductive path (52) and the third conductive path (53). In this way, n-1 auxiliary conductive paths (55) may be provided, each positioned between n conductive paths (51, 52, 53) (where n is an integer greater than or equal to 2).

[0115] The other configurations of the power module (10) in the modified example 5 of the embodiment are the same as those of the power module (10) in the modified example 3 of the embodiment.

[0116] Furthermore, similar to the 2nd modified embodiment, the third terminal (33), fourth terminal (34), fifth terminal (35), and sixth terminal (36) shown in Figure 16 may be omitted.

[0117] (Drive system and heat pump system) Figure 17 illustrates the configuration of a heat pump system (70) including a drive system (60). The heat pump system (70) comprises a refrigerant circuit (70a) filled with refrigerant and a power converter (61). The drive system (60) comprises the power converter (61) and a motor (65).

[0118] The refrigerant circuit (70a) includes a compressor (71), a heat exchanger (72), a pressure reducing mechanism (73), and an evaporator (74). In this example, the pressure reducing mechanism (73) is an expansion valve. The refrigerant circuit (70a) performs a vapor compression type refrigeration cycle.

[0119] The compressor (71) comprises a compression mechanism (71a) and a motor (65). The compression mechanism (71a) is connected to the motor (65) by a rotating shaft. The motor (65) rotates the compression mechanism (71a) by rotating the rotating shaft. The power converter (61) converts the power supply voltage supplied from the power source (5) into an output AC voltage having a predetermined frequency and amplitude, and supplies the output AC voltage to the motor (65). The motor (65) is driven by the power output from the power converter (61) (in this example, the output AC voltage).

[0120] In this example, the power converter (61) includes a converter (62), a DC section (63), and an inverter (64). The power supply (5) is a single-phase AC power supply, the output AC voltage is a three-phase AC voltage, and the motor (65) is a three-phase AC motor.

[0121] The converter (62) rectifies the power supply voltage supplied from the power supply (5), and the DC section (63) generates a DC voltage corresponding to the power supply voltage supplied from the power supply (5). The inverter (64) has a plurality of switching elements, and the switching operation of the plurality of switching elements converts the output of the DC section (63) into an output AC voltage having a predetermined frequency and amplitude.

[0122] The inverter (64) is composed of a power module (10). For example, the inverter (64) is constructed by connecting the first terminal (31), third terminal (33), fifth terminal (35), and first auxiliary terminal (41) of the power module (10) shown in Figure 14 to the first power line (61a), connecting the second terminal (32), fourth terminal (34), sixth terminal (36), and second auxiliary terminal (42) to the second power line (61b), and connecting the first output terminal (45), second output terminal (46), and third output terminal (47) to the three-phase coil (not shown) of the motor (65). The output of the converter (62) is applied between the first power line (61a) and the second power line (61b).

[0123] In the refrigeration cycle, the refrigerant discharged from the compressor (71) dissipates heat in the radiator (72). The refrigerant that flows out of the radiator (72) is depressurized in the depressurization mechanism (73) and evaporates in the evaporator (74). The refrigerant that flows out of the evaporator (74) is then drawn back into the compressor (71).

[0124] In this example, the heat pump system (70) is an air conditioner. The air conditioner may be a cooling-only unit or a heating-only unit. Alternatively, the air conditioner may be an air conditioner that switches between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way switching valve) that switches the direction of refrigerant circulation. The heat pump system (70) may also be a water heater, a chiller unit, a cooling device that cools the air inside a storage area, etc. The cooling device cools the air inside a refrigerator, freezer, container, etc.

[0125] (Other embodiments) The above explanation may be structured as follows:

[0126] The example given is when the auxiliary conductive path (55) is connected to the first auxiliary terminal (41) and the second auxiliary terminal (42), but the example is not limited to this.

[0127] For example, as shown in Figure 18, one end of the auxiliary conductive path (55) may be connected to the first auxiliary terminal (41), and the other end of the auxiliary conductive path (55) may be connected to the second terminal (32). In this case, by electrically connecting the first terminal (31) and the first auxiliary terminal (41), the auxiliary conductive path (55) can be electrically connected in parallel with the first conductive path (51). Alternatively, as shown in Figure 19, the other end of the auxiliary conductive path (55) may be connected to the first terminal (31). In this case, it is preferable to position the first auxiliary terminal (41) such that the straight-line distance between the first auxiliary terminal (41) and the second terminal (32) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32).

[0128] Furthermore, while embodiments and modifications have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Moreover, the designations "first," "second," "third," etc., in the specification and claims are used to distinguish the phrases to which these designations are given, and do not limit the number or order of such phrases. [Industrial applicability]

[0129] As explained above, it is useful as a power module, power converter, drive system, and heat pump system. [Explanation of Symbols]

[0130] 10 Power Modules 20 Casing 31 1st terminal 32 2nd terminal 33 3rd terminal 34 4th terminal 35 5th terminal 36 6th terminal 41 1st auxiliary terminal 42 2nd auxiliary terminal 45. First output terminal 46 Second output terminal 47 Third Output Terminal 51 First Conductive Path 52 Second Conduction Path 53 Third Conductive Path 60 Drive System 61 Power converter 65 Motor 70 Heat pump systems SW1 First switching element SW2 can perform the second switching. SW3 Third switching element SW4 4th switching element SW5 Fifth switching element SW6 6th switching element C1 Capacitor

Claims

1. Casing (20) and The casing (20) is provided with a first terminal (31), a second terminal (32), and a first auxiliary terminal (41) which are exposed to the outside of the casing (20), A first conductive path (51) is housed within the casing (20) and connects the first terminal (31) and the second terminal (32), An auxiliary conductive path (55) is housed within the casing (20), one end of which is connected to the first auxiliary terminal (41), and which can be electrically connected in parallel with the first conductive path (51), A first switching element (SW1) and a second switching element (SW2) are provided in series in the first conductive path (51), The system includes a capacitor (C1) provided in the auxiliary conductive path (55). Power module.

2. In the power module of claim 1, The straight-line distance between the terminal closer to the first auxiliary terminal (41) and the first auxiliary terminal (41) is shorter than the straight-line distance between the first terminal (31) and the second terminal (32). Power module.

3. In the power module of claim 1, The auxiliary conductive path (55) has a parallel portion (56) which is a portion that is parallel to a part or all of the first conductive path (51) at a predetermined distance (D1). Power module.

4. In the power module of claim 3, The predetermined interval (D1) is 2 mm or less. Power module.

5. In the power module of claim 3, The length (L1) of the parallel portion (56) of the auxiliary conductive path (55) is longer than the length (W0) of the auxiliary conductive path (55) in the width direction perpendicular to the direction along the auxiliary conductive path (55). Power module.

6. In the power module of claim 3, The ratio of the length (L1) of the parallel portion (56) to the total length (L0) of the auxiliary conductive path (55) in a direction perpendicular to the direction of the predetermined interval (D1) is 65% or more. Power module.

7. In the power module of claim 1, A second conductive path (52) that can be electrically connected in parallel with the first conductive path (51), The second conductive path (52) includes a third switching element (SW3) and a fourth switching element (SW4) arranged in series, The auxiliary conductive path (55) is arranged between the first conductive path (51) and the second conductive path (52). Power module.

8. A power conversion device comprising one power module from any one of claims 1 to 7.

9. A power conversion device according to claim 8, The system includes a motor (65) driven by power output from the power converter. Drive system.

10. A power conversion device according to claim 8, The compressor (71) includes a motor (65) driven by power output from the power converter and a compression mechanism (71a) driven by the motor (65). Heat pump system.

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