Cooling structure, electrical power converter including such a cooling structure, and vehicle

Abstract

Cooling structure (28), comprising a fluid distribution layer (1, 19) with a first and a second opening for a cooling fluid, which are arranged on opposite sides of the fluid distribution layer (1, 19), an elongated inner zone (4, 20) in which the first opening is positioned, an elongated outer zone (5, 21) in which the second opening is located, with two lateral arms (6, 7) that partially surround the inner zone (4, 20), a barrier (8) separating the inner zone (4, 20) and the outer zone (5, 21), in which the width of the inner zone (4, 20) decreases along a direction from the first opening to the second opening. In addition, an electrical power converter and a vehicle (33) are disclosed. Figure for summary: Fig. 1

Description

Title of the invention: Cooling structure, electric power converter comprising such a cooling structure and vehicle

[0001] The invention relates to a cooling structure and an electrical energy converter, in particular an inverter, comprising such a cooling structure. The invention also relates to a vehicle equipped with such an electrical power converter.

[0002] Electrical energy converters such as inverters are used to generate an alternating voltage, in particular a multi-phase alternating voltage, to operate an electric machine from a direct voltage supplied by a battery. The electric machine can be used as an electric motor to drive a wheel or an axle of an electrically powered vehicle.

[0003] The electrical power converter comprises controllable switches, for example controllable semiconductor switches such as IGBTs. During operation of the electrical power converter, a significant amount of heat is generated, which must be dissipated in order to maintain the operating temperature of the semiconductors below a predetermined limit.

[0004] EP 2416483 A2 describes a double-sided single-phase power module, which is directly cooled. In particular, the power module comprises a plate from which pins extend. The pins are intended to be inserted into an opening of a flow path, so that a coolant circulating in the flow path comes into contact with the pins.

[0005] WO 2022 / 248427 A1 discloses a cooling structure comprising a plurality of layers and an array of local chambers distributed between the plurality of layers stacked on top of each other in a stacking direction, wherein each local chamber comprises at least two openings, at least one of which is in communication with a local chamber of another of the layers, and wherein each local chamber comprises one or more meander-shaped structures blocking any direct path into the local chamber between the two openings. In each local chamber, the coolant flowing between the two openings is forced into contact with at least one meander-shaped structure, so that heat can be transferred relatively easily from a wall of the meander-shaped structure to the coolant. Each layer comprises one or more meander-shaped structures.Between the inlet of the cooling structure and the outlet, the temperature of the coolant increases, this . which allows heat to be dissipated from the power module including the cooling structure.

[0006] The object of the invention is to provide a cooling structure with a more homogeneous temperature distribution.

[0007] This objective is achieved by means of a cooling structure having the characteristics of claim 1.

[0008] The inventive cooling structure comprises: a fluid distribution layer with a first opening and a second opening for a cooling fluid, which are arranged on opposite sides of the fluid distribution layer, an elongated inner area, in which the first opening is positioned, an elongated outer area, in which the second opening is positioned, with two side arms, which partially surround the inner area, a barrier separating the inner area and the outer area, in which the width of the inner area decreases along a direction from the first opening to the second opening.

[0009] The inventive cooling structure is particularly well suited for an electrical energy converter comprising several semiconductor switches, since the cooling structure ensures that the semiconductor switches are cooled homogeneously. Another advantage of the invention is that the pressure loss of the cooling fluid is lower than that of the structure of WO 2022 / 248427 A1, so that less energy is required to transport the cooling fluid in a closed circuit.

[0010] The first opening in the fluid distribution layer may be an inlet for the cooling fluid and the second opening may be an outlet. However, another embodiment is also possible, in which the inlet and outlet are reversed, resulting in a reversed flow of the cooling fluid.

[0011] As indicated above, the width of the inner region decreases along a direction from the first opening, preferably the inlet, to the second opening, preferably the outlet. Preferably, the width of the outer region of the fluid distribution layer increases.

[0012] It is preferable that the barrier has a U or V shape. This shape ensures that the width of the inner zone decreases from the inlet to the outlet, in the longitudinal direction of the cooling structure, while the width of the outer zone increases.

[0013] The terms "U-shaped" and "V-shaped" are to be understood in a broad sense. The legs of a U-shaped barrier are not necessarily perpendicular. A U-shaped barrier may have legs that slope slightly outward. Such a U-shaped barrier may have a relatively shorter central portion than its feet. Furthermore, a V-shaped barrier does not necessarily have a sharp edge. The junction of the legs of a V-shaped barrier can also be rounded.

[0014] According to a preferred embodiment, it is possible to envisage that the width of the inner zone gradually decreases. This structure makes it possible to adapt the flow sensitively to the position of several semiconductor switches, which are placed next to each other in the longitudinal direction of the cooling structure.

[0015] It is also possible for the outer edges of the inner zone to be inclined relative to an axis running from the inlet to the outlet. The outer edge of the inner zone can be divided into several parts, each part having a different inclination relative to the longitudinal axis. An inventive cooling structure with inclined outer edges can also be adapted very precisely in order to influence the flow of the cooling fluid.

[0016] It is particularly preferable that the inner zone and the outer zone are essentially symmetrical about an axis running from the inlet to the outlet. This characteristic will also contribute to a homogeneous temperature distribution.

[0017] Preferably, a fluid separation plate is arranged between the fluid distribution layer and the stacked layers of the cooling structure, the fluid separation plate comprising through openings, which are either in communication with the inner area or with the outer area. Preferably, the openings of the fluid separation plate are located in the same location as the semiconductor switches of the inverter, so that the cooling fluid is routed to the correct position.

[0018] In this regard, it is also possible to envisage that the through openings are formed by slots arranged along a direction from the inlet to the outlet. Such slots do not substantially impair the flow pressure.

[0019] The inventive cooling structure may comprise several layers and an array of local chambers distributed between the several layers stacked on top of each other in a stacking direction, in which each local chamber comprises at least two openings, at least one of which is in communication with a local chamber of another of the layers, in which each local chamber comprises one or more meander-shaped structures blocking any direct path into the local chamber between the two openings. The invention makes it possible to dissipate heat from power electronic components having a high power density.

[0020] The invention also relates to an electrical energy converter, in particular an inverter, comprising a power module with semiconductor power components, arranged on a substrate, a base plate, on which the substrate is arranged, and an inventive cooling structure, arranged under the base plate. base.

[0021] Preferably, the inverter is a multi-phase inverter, in which the through openings of the fluid separation plate, in particular the slots, are arranged in rows, the number of rows corresponding to the number of phases.

[0022] Preferably, the cooling structure is housed in a housing having an inlet and an outlet for the cooling fluid.

[0023] The invention also relates to a vehicle comprising a battery, a multi-phase electric motor configured to drive at least one wheel and an inventive electric power converter.

[0024] The invention is explained by means of a preferred example with reference to the drawings. The drawings are schematic representations and show:

[0025] [Fig-1] a top view of a fluid distribution layer;

[0026] [Fig.2] a top view of a fluid separation plate;

[0027] [Fig.3] a layer of crossed meanders;

[0028] [Fig.4] several layers of transverse meanders;

[0029] [Fig.5] an upper plate;

[0030] [Fig.6] a sectional side view of the inventive cooling structure;

[0031] [Fig.7] sectional view of a cooling structure;

[0032] [Fig.8] a second embodiment of a fluid distribution layer; and

[0033] [Fig.9] an inventive vehicle.

[0034] [Fig.l] is a top view of a rectangular fluid distribution layer 1 which has an approximately rectangular shape. The fluid distribution layer 1 is a component of a cooling structure. An inlet 2 for a cooling fluid and an outlet 3 are arranged on opposite sides of the fluid distribution layer 1. The inlet 2 is placed in an elongated inner zone 4. An elongated outer zone 5 is provided with two side arms 6, 7, which partially surround the inner zone 4. A barrier 8 separates the inner zone 4 from the outer zone 5. In the example of [Fig.l], the barrier 8 has the shape of a V. Along the longitudinal direction, which extends between the inlet and the outlet, the width of the inner zone 4 decreases, while the width of the outer zone 5 increases. The inner zone 4 and the outer zone 5 are essentially symmetrical about a longitudinal axis which extends between the inlet 2 and the outlet 3.

[0035] [Fig. 2] shows a fluid separation plate 9 which, in the installed state, is placed on the fluid distribution layer 1. The fluid separation plate 9 comprises three through openings 10, which are arranged in a row in the longitudinal direction. The through openings 10 are placed along the center of the fluid separation plate 9, so that they are in communication with the inner area 4 of the fluid distribution layer 1. Furthermore, other or Through openings 11 are arranged on either side of the through openings 10. The through openings 10 and the other through openings 11 are arranged parallel to each other. All the through openings 10, 11 are formed by slots. The through openings 10 in the center are marked with a dot, the outer through openings 11 are marked with a cross. These signs symbolize the direction of flow. A dot indicates that the coolant flows downwards, out of the plane, while a cross indicates that the coolant flows downwards, in the plane. The function of the fluid separation plate 9 is to distribute the coolant between several power modules. In the example shown, there are three power modules, which are arranged at the top of the cooling structure.

[0036] [Fig. 3] shows a cross-meander layer 12, placed above the fluid separation plate 9. In this embodiment, the cross-meander plate 12 comprises three separate and identical meander zones 13, each having an approximately square shape. Each meander zone 13 comprises meander structures oriented in the transverse direction. The meander zones 13 are separated from each other by transverse separators. The cold cooling fluid from the fluid separation plate 9 rises and enters the middle of the cross-meander layer 12, indicated by the dots. The central part of the cross-meander layer 12 is limited by two parallel barriers 14, represented by lines. Due to the meander structure, the cold cooling fluid absorbs heat from the cross-meander layer 12, which is made of metal, and heats up.The separators between the meander zones 13 and the barriers 14 cause the cooling fluid that is between the parallel barriers 14 to flow only higher. As indicated by the crosses, the hot cooling fluid in the two outer parts of the cross-meander layer 12 flows downwards to the fluid separation plate 9. It should be noted that the width of the two outer parts of the cross-meander layer 12 is different, which means that the barriers 14 are not arranged symmetrically with respect to the center line (longitudinal axis).

[0037] [Fig. 4] shows a total of four cross-meander layers stacked on top of each other. The first cross-meander layer 12 has been described previously. The second cross-meander layer 15 has a structure similar to that of the first cross-meander layer 12, except for the position of the barriers 14. The parallel barriers 14 of the first cross-meander layer 12 are offset by a certain degree from the center line to the right side, while the barriers 14 of the second cross-meander layer 15 are offset by a certain degree from the center line to the left side. A third cross-meander layer 16 is identical to the first cross-meander layer 12 and a fourth cross-meander layer 15 is identical to the first cross-meander layer 12. cross meanders 17 is identical to the second layer of cross meanders 15. Since the position of the barriers 14 is not symmetrical about the central axis and alternates from one layer to another, the coolant is forced to mix and go from top to bottom. The stacked layers 12, 15, 16, 17 create a 3D structure circuit.

[0038] [Fig.5] shows an upper plate 18, placed on the fourth layer of crossed meanders 17, which seals the cooling structure and ensures a good thermal connection with the power modules.

[0039] [Fig. 6] is a cross-sectional view, in the direction of flow, of an inverter 22 configured to convert a DC voltage into an AC voltage. The arrow "V" indicates the vertical direction. The arrow "F" indicates the direction of flow. The inverter 22 includes a DC link capacitor (not shown) configured to smooth the DC voltage. The conversion of the DC voltage into an AC voltage is performed by a power module 23 comprising a base plate 24 and a substrate 25 fixed on an upper face of the base plate 24. The power module 23 further includes controllable switches, which are power semiconductor components 26 supported by the substrate 25. The power module 23 includes an electrically insulating housing 27 surrounding the substrate 25 and the power semiconductor components 26, while a lower face of the base plate 24 is uncovered.The power module 23 further comprises a cooling structure 28 fixed on the underside of the base plate 24.

[0040] A sectional view of a fluid distribution layer 29, configured to guide the cooling fluid, is shown under the power module 23. The fluid distribution layer 29 comprises an inlet 30 and an outlet 31. In the sectional view, the barrier 8 between the inner area and the outer area is also visible. The cooling structure 28 has elongated side walls and is configured to be attached to the power module 23, such that the stacked cross-meander layers 12 are received in a cavity of the cooling structure. The cooling structure 28 and the inverter 22 comprising the power module 23 are attached to each other and sealed.

[0041] The coolant is intended to pass through chambers 32 in the meander zones of the cross-meander layers 12 along the flow direction F perpendicular to the vertical direction V to flow from the inlet 30 to the outlet 31. The local chambers 32 are formed by holes and are distributed between several cross-meander layers 12 stacked on top of each other along the vertical direction. Each layer comprises meander-shaped structures, as shown in [Fig. 3]. The chambers are stacked in an offset manner, so that in order to circulate between two consecutive local chambers 32, the coolant must cross a chamber of another cross-meander layer 12. In order to allow the flow of the coolant between the chambers of different layers, each chamber 32 overlaps the chambers of an adjacent layer. The overlap between two local chambers 32 of adjacent layers forms an opening for the coolant allowing the communication of the coolant between these two local chambers 32. When the coolant flows through the cross-meander layers 12, the heat generated by the semiconductor power components 26 is dissipated from the base plate 24.

[0042] [Fig. 7] is a sectional view of the cooling structure 28 shown in [Fig. 6], perpendicular to the direction of flow. The barrier 8 separates the inner zone 4 from two outer zones 5.

[0043] [Fig. 8] shows a second embodiment of a fluid distribution layer 19, which is similar to the fluid distribution layer 1. The fluid distribution layer 19 has an inlet 2, an outlet 3, an elongated inner zone 20, which is surrounded by an outer zone 21. In contrast to the first embodiment, the width of the inner zone 20 gradually decreases from the inlet to the outlet. The inner zone 20 comprises three regions symmetrical about the center line. The widths of these regions decrease from the inlet 2 to the outlet 3.

[0044] [Fig. 9] shows a motor vehicle 33, comprising wheels 34 and an electric drive 35 configured to drive one or more wheels directly or indirectly. The vehicle 33 comprises a DC voltage source 36, such as a battery, for electrically powering the electric drive 35. The DC voltage source 36 is configured to provide a DC voltage E.

[0045] The electric drive 35 comprises an electric motor 37 and an inverter 38 configured to drive the electric motor 37 by providing electrical energy. In this embodiment, the electric motor 37 is a rotary electric motor comprising stator phases. In the described example, the electric motor 37 is a three-phase electric motor comprising three stator phases.

[0046] The inverter 38 comprises input terminals IT+, IT- connected to the DC voltage source 36 such that the DC voltage E is present at the input terminals IT+, IT-. More specifically, the input terminals IT+, IT- comprise a positive input terminal IT+ connected to a positive terminal of the DC voltage source 36 and a negative input terminal IT- connected to a negative terminal of the DC voltage source 106 and to an electrical ground GND.

[0047] The inverter 38 also includes output terminals OT connected to the electric motor 37. An alternating voltage must be present at the output terminals OT to power the electric motor 37. The alternating voltage may be a single-phase or multi-phase alternating voltage. In the example described where the electric motor 37 is a three-phase electric motor, the alternating voltage is a three-phase alternating voltage.

[0048] The inverter 38 further comprises controllable switches Q, Q', called main switches, connected to the input terminals IT+, IT- and to the output terminals OT. The main switches Q, Q' are semiconductor switches comprising for example transistors. Each main switch Q, Q' comprises for example one of the following elements: a metal oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT) and a silicon carbide MOSFET (SiC MOSFET). These switches Q, Q' correspond to the semiconductor power components 26 of [Fig. 6]. In the described embodiment, the inverter 38 comprises switching elements 39 respectively associated with the stator phases of the electric motor 37.Each switching element 39 comprises a high-side (HS) main switch Q' connected to the positive input terminal IT+ and a low-side (LS) main switch Q connected to the negative input terminal IT. The HS main switch Q' and the LS main switch Q are connected to each other at a central point connected to the output terminal OT connected to the associated stator phase of the electric motor 37.

[0049] Each switching element 39 is intended to be controlled to switch between two configurations. In the first, called high side (HS) configuration, the main switch HS Q' is closed (on) and the main switch LS Q is open (off) so that the DC voltage E is essentially applied to the associated stator phase. In the second, called low side (LS) configuration, the main switch HS Q' is open (off) and the main switch LS Q is closed (on) so that a zero voltage is essentially applied to the associated stator phase.

[0050] The inverter 38 further comprises a control device 40 configured to control the main switches Q, Q' so that the main switches Q, Q' convert the direct voltage E into alternating voltage. In the example described, the control device 40 is configured to switch each switching element 39 between the two configurations mentioned above. The power module 23 may implement, for example, one of the switching elements 39 or all of the switching elements 39.

[0051] It will be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in light of the teaching which has just been disclosed.

[0052] List of reference numbers

[0053] 1: fluid distribution layer

[0054] 2: entry

[0055] 3: outlet

[0056] 4: Inner zone

[0057] 5: outer zone

[0058] 6: side arms

[0059] 7: side arms

[0060] 8: barrier

[0061] 9: fluid separation plate

[0062] 10 through opening

[0063] 11 through opening

[0064] 12 cross-meander layer

[0065] 13 meander zone

[0066] 14 barrier

[0067] 15 second cross-meander layer

[0068] 16 third cross-meander layer

[0069] 17 fourth cross-meander layer

[0070] 18 top plate

[0071] 19 fluid distribution layer

[0072] 20 inner zone

[0073] 21 outer zone

[0074] 22 inverter

[0075] 23 power module

[0076] 24 base plate

[0077] 25 substrate

[0078] 26 semiconductor power components

[0079] 27 housing

[0080] 28 cooling structure

[0081] 29 fluid distribution layer

[0082] 30 inlet

[0083] 31 outlet

[0084] 32 local chamber

[0085] 33 vehicle

[0086] 34 wheels

[0087] 35 electric drive

[0088] 36 voltage sourceDC

[0089] 37 electric motor

[0090] 38 inverter

[0091] 39 switching element

[0092] 40 control device

Claims

Claims

1. Cooling structure (28), comprising - a fluid distribution layer (1, 19, 29) with - a first opening and a second opening for a cooling fluid, which are arranged on opposite sides of the fluid distribution layer (1, 19, 29), - an elongated inner area (4, 20), in which the first opening is located, - an elongated outer area (5, 21), in which the second opening is placed, with two side arms (6, 7), which partially surround the inner area (4, 20), - a barrier (8) separating the inner area (4, 20) and the outer area (5, 21), in which the width of the inner area (4, 20) decreases along a direction from the first opening to the second opening.

2. A cooling structure according to claim 1, wherein the first opening is an inlet (2) for the cooling fluid and the second opening is an outlet (3) or vice versa.

3. A cooling structure according to claim 1 or 2, wherein the width of the outer zone (5, 21) increases along a direction from the first opening to the second opening.

4. Cooling structure according to one of the preceding claims, wherein the barrier (8) has a U or V shape.

5. Cooling structure according to one of the preceding claims, wherein the width of the inner zone (4, 20) gradually decreases.

6. Cooling structure according to one of the preceding claims, wherein the outer edges of the inner zone (4, 20) are inclined relative to an axis running from the first opening, in particular the inlet (2), to the second opening, in particular the outlet (3).

7. Cooling structure according to one of the preceding claims, wherein the inner zone (4, 20) and the outer zone (5, 21) are essentially symmetrical with respect to an axis extending from the first opening, in particular the inlet (2), to the second opening, in particular the outlet (3).

8. Cooling structure according to one of the preceding claims, in which a fluid separation plate (9) is arranged between the fluid distribution layer (1, 19, 29) and the stacked layers (12, 15, 16, 17) of the cooling structure (28), wherein the fluid separation plate (9) comprises through openings (10, 11), which are either in communication with the inner zone (4, 20) or with the outer zone (5, 21).

9. A cooling structure according to claim 8, wherein the through openings (10, 11) are formed of slots arranged along a direction from the inlet (2) to the outlet (3).

10. A cooling structure according to any preceding claim, comprising a plurality of layers (12, 15, 16, 17) and an array of local chambers (32) distributed between the plurality of layers (12, 15, 16, 17) stacked on top of each other in a stacking direction, wherein each local chamber (32) comprises at least two openings, at least one of which is in communication with a local chamber (32) of another of the layers (12, 15, 16, 17), wherein each local chamber (32) comprises one or more meander-shaped structures blocking any direct path into the local chamber (32) between the two openings.

11. Electrical power converter, in particular inverter (38), comprising: - a power module (23) with semiconductor power components (26), arranged on a substrate (25), - a base plate (24), on which the substrate (25) is arranged, and - a cooling structure (28) according to one of claims 1 to 10, arranged under the base plate (24).

12. An electrical energy converter according to claim 11, wherein the inverter (38) is a multi-phase inverter, wherein the through openings (10, 11) in the fluid separation plate (9), in particular the slots, are arranged in rows, the number of rows corresponding to the number of phases.

13. An electrical power converter according to claim 11 or 12, wherein the cooling structure (28) is received in a housing (27) with an inlet (30) and an outlet (31) for the cooling fluid.

14. Vehicle (33) comprising a battery, a multi-phase electric motor (37) configured to drive at least one wheel and an electric power converter according to any one of claims 11 to 13.

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