Power electronics cooler, power electronics device and inverter

Abstract

The insert plate (EP) has a through opening (BO, TO) for allowing some of the coolant to pass directly through from the supply flow channel portion (ZF) to the return flow channel portion (RF) and, at the through opening (BO, TO), a temperature-controlled valve (VT) which is configured to block or release the flow of coolant through the through opening depending on the coolant temperature in the supply flow channel portion (ZF) and / or in the return flow channel portion (RF). The invention further relates to a power electronics device and to an inverter having a cooler of this kind.

Description

[0001] Description

[0002] Power electronics cooler, power electronics device and inverter

[0003] Technical area:

[0004] The present invention relates to a power electronics cooler or a cooler for cooling a power electronics device, for example, a DC / DC converter or an inverter, in particular an electric drive of a motor vehicle. Furthermore, the invention relates to a power electronics device with such a cooler and to an inverter with such a power electronics device.

[0005] State of the art and task of the invention:

[0006] Power electronics coolers for cooling a power electronics device are known and are used, among other things, in (power) DCDC converters or (power) inverters, e.g. of electrically powered vehicles, for cooling the power electronics devices or power modules (with several power semiconductor switches or comparable circuit components with high power losses) of the DCDC converters or inverters.

[0007] For example, in so-called EPF2.3 inverters (a product of Vitesco Technologies GmbH), coolers are used to cool a power electronics device of the inverter or its power modules (with several power semiconductor switches).

[0008] With such coolers, due to the circuitry nature of the power device or its power modules, there is a requirement for homogeneous cooling of the power device or its power modules (and all power semiconductor switches or all comparable circuit components with high power losses). This is intended to avoid local high temperature peaks on the power device or its power modules, which could otherwise lead to a drop in performance, malfunctions or even the failure of the power device or inverter, or at least to a reduction in the service life. The object of the present application is therefore to provide a possibility with which a power electronics device, e.g. an inverter or a DCDC converter, or its power modules (with several power semiconductor switches orcomparable circuit components with high power losses) can be cooled homogeneously.

[0009] Description of the invention:

[0010] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0011] According to a first aspect of the invention, a power electronics cooler or a cooler for cooling a power electronics device, for example a DCDC converter or an inverter, in particular of an electrically powered vehicle, is provided.

[0012] The radiator has a base plate and a cover plate, which together (at least partially) enclose a cooling channel that extends in a longitudinal direction of the radiator and serves for the flow of a coolant, such as cooling water.

[0013] The cooler further comprises a coolant inlet and a coolant outlet, which are arranged at a first longitudinal end of the cooling channel when viewed in the longitudinal direction (in particular next to one another and thus one behind the other when viewed in a transverse direction of the cooler).

[0014] The cooler also has an insert plate which is arranged in the cooling channel between the base plate and the cover plate and divides the cooling channel into (at least) one supply flow channel section extending from the coolant inlet to a second longitudinal end of the cooling channel facing away from the first longitudinal end, and (at least) one return flow channel section extending from the second longitudinal end of the cooling channel to the coolant outlet. The insert plate encloses the supply flow channel section with the base plate (at least partially or up to openings to be described below) and the cover plate encloses the return flow channel section (at least partially or up to the openings to be described below). The insert plate has (at least) one through-opening (orThe cooling element has a through-passage recess (i.e., a lateral cutout on the insert plate) designed to conduct the coolant from the supply flow channel section to the return flow channel section. The through-passage opening connects the supply flow channel section and the return flow channel section in series with each other.

[0015] Furthermore, the insert plate has (at least) one passage opening between the coolant inlet and the through-opening and thus between the first and the second longitudinal end of the cooling channel for passing a part of the coolant from the supply flow channel section directly - i.e. without flowing through the through-opening - to the return flow channel section.

[0016] In addition, the insert plate has a temperature-controlled valve at the passage opening, which is designed to control and / or regulate the coolant flow through the passage opening depending on coolant temperatures in the supply flow channel section and / or in the return flow channel section, i.e. to (completely) block or (partially or completely) release the flow through the passage opening.

[0017] The cover plate, the insert plate, and the base plate can each be formed as a largely plate-shaped cooler part with correspondingly shaped side sections, which together enclose the cooling channel (except for the coolant inlet and the coolant outlet) in a fluid-tight manner. If necessary, the insert plate can be arranged between the base plate and the cover plate and can be separated non-destructively from the base plate and the cover plate or removed from the cooling channel, and can also be mechanically connected to them.

[0018] Viewed in a direction perpendicular to the insert plate or cooler (and thus in a direction perpendicular to the plane in which the longitudinal and transverse directions of the cooler run), the cover plate, the return flow channel section, the insert plate, the feed flow channel section and the base plate are arranged one above the other in this order. The feed flow channel section and the return flow channel section are connected in series with each other in terms of flow technology and together form a laterally tilted U-shaped (i.e. in the form of ZD or <z) Kühlkanal, wobei das Kühlmittel beim Betrieb des Kühlers in den beiden Kanalabschnitten in jeweils einer von zwei zueinander entgegengesetzten Strömungsrichtungen fließt (in einer Zuführströmung und einer Rückführströmung).

[0019] The cover plate can serve, in particular, for (direct) thermal contacting of the power electronics device. In other words, circuit components of the power electronics device with high power dissipation or high waste heat, such as power semiconductor switches, can be (directly) arranged on the cover plate or thermally contacted with it. The cover plate can thus serve as a heat exchanger from the aforementioned circuit components of the power electronics device to the coolant flowing through the cooling channel. In particular, the cover plate can be formed as a circuit carrier, such as a ceramic substrate, of the power electronics device or its power modules, on which the aforementioned circuit components are arranged and electrically connected.

[0020] The actual heat absorption from the cover plate and thus the cooling of the circuit components of the power electronic device (with high power loss or high waste heat, such as power semiconductor switches) arranged on the cover plate and thermally connected to it occurs primarily through the return flow channel section or the coolant flowing through the return flow channel section.The supply flow channel section primarily serves to guide the coolant from the coolant inlet to the second longitudinal end of the cooling channel facing away from the coolant inlet, so that the coolant can flow at the second longitudinal end through the through-opening from the supply flow channel section to the return flow channel section and can flow (back) from the second longitudinal end over the entire length of the cooler and thus over the entire length of the cover plate to the coolant outlet at the first longitudinal end of the cooler, in order to absorb the waste heat from the cover plate and thereby cool the circuit components of the power electronics device.

[0021] The cover plate can be made of a known (especially thermally highly conductive) cooler material, such as aluminum or an aluminum alloy, in order to better absorb the waste heat from the circuit components of the power electronics device arranged on the cover plate and transfer it to the coolant flowing around the cover plate.

[0022] The insert plate and the base plate can be made of the same material as the cover plate or of another known, lightweight and inexpensive (especially one with good thermal conductivity) material, such as a plastic.

[0023] The coolant inlet and the coolant outlet may be formed as parts of the base plate on the base plate.

[0024] During cooling operation of the cooler, the passage opening directs a portion of the coolant from the supply flow channel section directly to the return flow channel section and allows this portion of the coolant to bypass or not flow through sections of the supply flow channel section and the return flow channel section.

[0025] This allows the portion of the coolant that is still cool to bypass sections of the supply and return flow channel sections and mix with the remaining coolant, which flows over the entire flow path from the supply flow channel section through the through-holes to the return flow channel section and is relatively warm, in the middle of the return flow channel section. This achieves a largely uniform temperature in the coolant in the return flow channel section and reduces the overall pressure drop in the cooling channel.

[0026] Furthermore, the part of the coolant flowing through the passage opening directly into the return flow channel section can generate additional (laminar) flows in the channel area of ​​the return flow channel section around the passage opening, thereby preventing the coolant from accumulating or circulating in this channel area and thus forming a so-called dead water area.

[0027] In particular, the passage opening interrupts an asymmetric flow of the coolant in the return flow channel section, thus ensuring largely homogeneous cooling of the cover plate without a temperature hotspot in the return flow channel section or on the cover plate. The temperature-controlled valve can be used to influence and control the entire flow of the coolant through the return flow channel section during the (entire) cooling operation of the cooler in terms of pressure loss, flow velocity, and flow direction in the return flow channel section.The temperature-controlled valve changes the coolant flow through the passage opening during the (entire) cooling operation of the cooler continuously and without any active external intervention, automatically and depending on the coolant temperatures in the supply flow channel section and / or in the return flow channel section, so that during the (entire) cooling operation, an averaging of the cooling water temperature over the entire return flow channel section is achieved and maintained by targeted dynamic cooling water mixing.

[0028] This provides a possibility to homogeneously cool a power electronics device, e.g. an inverter or a DCDC converter, or its power modules (with several power semiconductor switches or comparable circuit components with high power losses).

[0029] Several passage openings can be provided, which are distributed in the longitudinal and transverse direction of the cooling channel and are thus located at different positions on the insert plate.

[0030] The passage opening can be a bypass opening which is designed to directly pass a part of the coolant from the supply flow channel section without flowing through the passage opening directly to the return flow channel section.

[0031] The bypass opening is used to divert a portion of the coolant directly from the supply flow channel section to the return flow channel section without flowing through the entire flow path from the supply flow channel section via the through-openings to the return flow channel section. This allows the portion of the coolant that is still cool to bypass sections of the supply and return flow channel sections and mix with the remaining coolant, which is relatively warm and flows along the entire flow path from the supply flow channel section via the through-openings to the return flow channel section, in the middle of the return flow channel section. This achieves a largely uniform temperature in the coolant in the return flow channel section and reduces the overall pressure drop in the cooling channel.For this purpose, several bypass openings can be provided, which are evenly distributed over the entire surface of the insert plate in order to achieve the most homogeneous mixing of the coolant in the return flow channel section.

[0032] The passage opening may also be a dead water opening configured to directly pass a portion of the coolant from the supply flow channel section directly to a possible dead water region of the return flow channel section.

[0033] A dead water zone is a channel area in the return flow channel section in which the coolant would accumulate or would not flow away from the through-opening to the coolant outlet within a predetermined period of time in the main flow direction if the insert plate did not have the above-mentioned through-opening. Accordingly, the description always refers to a "possible" dead water zone. The dead water zone is also, in particular, a turbulent flow area in the return flow channel section, similar to a separation bubble, which would be separated from the (usually laminar) main flow of the coolant or would be difficult to reach or flow through if the insert plate did not have the above-mentioned through-opening.During the development of the invention and through multiple tests under various and as realistic as possible environmental and operating conditions with a comparable cooler without the aforementioned passage opening in the insert plate, it was determined that the dead water zone forms in particular around a corner or on a side area of ​​the return flow channel section. A dead water zone can also be considered to be an area in the return flow channel section in which the coolant recirculates or stagnates and thus cannot flow through or out. The dead water zone in the return flow channel section is determined, for example, in a flow simulation using a cooler with an insert plate without the previously described passage opening.An area in the return flow channel section is defined as a dead water area if the coolant in the return flow channel section does not flow from the through-opening to the coolant outlet in its main flow direction within a predetermined period of time, but circulates in the said area or stagnates or stops in its flow movement. The through-opening for passing a portion of the coolant from the supply flow channel section directly to the potential dead water area of ​​the return flow channel section enables the (and thus still cold) coolant flowing from the coolant inlet into the supply flow channel section or flowing through the supply flow channel section to directly bypass the potential dead water area.Because this area is cooled with the coolant flowing fresh into the cooling channel and thus comparatively cold, this area is cooled in advance compared to the rest of the cover plate.

[0034] The passage opening can be positioned and dimensioned in the insert plate depending on the determined, potential dead water area, so that the potential dead water area in the return flow channel section can be surrounded as completely as possible by a sufficient amount of coolant, which flows from the supply flow channel section through the passage opening directly into the potential dead water area. This enables a comparatively homogeneous flow around the entire return flow channel section, which in turn allows for comparatively homogeneous cooling of the cover plate without a temperature hot spot on the cover plate caused by a dead water area.

[0035] The dead water area in the return flow channel section can be determined in a flow simulation, such as a CFD simulation (CFD: in English "Computational Fluid Dynamics", in German "Numerische Strömungsmechanik"), using a comparable cooler with an insert plate without the aforementioned passage opening.

[0036] The passage opening can then be positioned and dimensioned (shape and dimensions, such as diameter) in the insert plate depending on the determined, potential dead water area. Furthermore, multiple passage openings can be installed, whereby their number as well as their respective positions and dimensions (shape and dimensions or diameter) of the passage openings can be determined, among other things, depending on the location and dimensions of the potential dead water area (expected without the passage opening). In the case of multiple passage openings, some of them can act as bypass openings and the remainder as dead water openings.

[0037] The valve can be designed as a diaphragm valve.

[0038] The valve may also be formed as a bimetal valve.

[0039] In addition, the valve can be configured to block or release the coolant flow through the passage opening depending on the temperature difference between the temperatures of the coolant in the supply flow channel section and in the return flow channel section.

[0040] The valve may also be configured to block or release the coolant flow through the passage opening depending on local coolant temperatures in the supply flow channel section and / or in the return flow channel section and around the passage opening and / or on the temperature difference between these local coolant temperatures.

[0041] Here, the local coolant temperatures are the coolant temperatures in channel areas of the supply flow channel section or the return flow channel section around the passage opening.

[0042] The valve can further be configured to not release, or partially or completely release, the coolant flow through the passage opening depending on the (local) coolant temperatures in the supply flow channel section and in the return flow channel section and around the passage opening and / or the temperature difference between these (local) coolant temperatures and thus to control or regulate the coolant flow through the passage opening or the flow rate of the part of the coolant flowing through the passage opening.

[0043] The insert plate can have a return opening (or a return recess, i.e. another lateral cutout on the insert plate) at the first longitudinal end or in the region of the first longitudinal end of the cooling channel and (immediately) in front of the coolant outlet, which serves to guide the coolant from the return flow channel section to the coolant outlet and is fluidically separated, in particular sealed, from the supply flow channel section by a sealing wall that (at least partially) surrounds the return opening. The return flow channel section is directly fluidically connected to the coolant outlet through the return opening. The sealing wall even fluidically seals the return flow channel section and the coolant outlet from the supply flow channel section and the coolant inlet, so that direct flow of the coolant from the coolant inlet or outlet is prevented.from the supply flow channel section directly into the return flow channel section or the coolant outlet is effectively prevented.

[0044] The term "fluidically connected" means that a direct flow of coolant from a first cooling channel section to another cooling channel section "fluidically connected" to this first channel section is continuously possible. Similarly, the term "fluidically separated" means that a direct flow of coolant from the first cooling channel section to a third cooling channel section "fluidly separated" from this first channel section is permanently prevented.

[0045] The sealing wall can be formed on the insert plate and / or the base plate and extend from the insert plate toward the base plate or away from the base plate toward the insert plate. The sealing wall can extend from the insert plate toward the base plate as a further projection of the insert plate (or as a further fixed component of the insert plate). Alternatively or additionally, the sealing wall can also extend from the base plate toward the insert plate as a projection of the base plate (or as a fixed component of the base plate).

[0046] The cover plate and / or the insert plate may have a surface-enlarging structure, such as cooler pin fins, that protrude into the return flow channel section.

[0047] The cooler can have a flow guide structure and / or a flow guide wall in the supply flow channel section, which are configured to guide the coolant from the coolant inlet or from the bypass channel region to the through-opening. The flow guide structure or the flow guide wall can extend in the longitudinal direction of the cooling channel. The flow guide structure or the flow guide wall can protrude from the insert plate into the supply flow channel section as a further projection of the insert plate (or as a further fixed component of the insert plate). Alternatively or additionally, the flow guide structure or the flow guide wall can also protrude from the base plate into the supply flow channel section as a further projection of the base plate (or as a further fixed component of the base plate).

[0048] The cooler or the base plate can have a ramp-shaped elevation at the coolant inlet, which extends obliquely to the bypass opening and is designed to direct the coolant from the coolant inlet in the direction of the bypass opening.

[0049] According to a second aspect of the invention, a power electronics device is provided which, for example, forms part of a DCDC converter or an inverter.

[0050] The device comprises at least one power module and a previously described cooler, wherein the power module is arranged on a surface of the cover plate facing away from the return flow channel section and is thermally contacted or connected to the cover plate.

[0051] The cover plate can be formed as a circuit carrier, such as a DCB substrate or an AM B substrate, or a part thereof. The power module can include power semiconductors, which can be formed as SiC semiconductor switches or IGBT semiconductor switches.

[0052] According to a third aspect of the invention, an inverter is provided that comprises the aforementioned power electronics device and a control circuit (or a driver circuit) for controlling (or operating) the power electronics device or the power module. The control circuit is electrically (or signal-wise) connected to the power module of the power electronics device or the power semiconductors of the power module via control signal connections.

[0053] Brief description of the drawings: An exemplary embodiment of the invention is explained in more detail below with reference to the accompanying drawings. In the drawings:

[0054] Figure 1 shows, in a schematic cross-sectional view, parts of an inverter with a cooler according to an exemplary embodiment of the invention; and

[0055] Figure 2 shows a schematic plan view of parts of the cooler from Figure 1.

[0056] Detailed description of the drawings:

[0057] Figures 1 and 2 each show, in a schematic cross-sectional and plan view, parts of an inverter with a cooler according to an exemplary embodiment of the invention, which serves, for example, as a power inverter of an electric drive system of a motor vehicle for providing phase currents for a drive electric motor of the drive system.

[0058] The inverter has a power device LV with a cooler KL for cooling the power device LV, on which the power device LV is arranged and is also mechanically and thermally connected thereto.

[0059] The power device LV has a circuit carrier made, for example, of an aluminum alloy or a thermally conductive ceramic, which at the same time forms a cover plate DP of the cooler KL.

[0060] On a surface OF of the circuit carrier or cover plate DP facing away from the cooler KL, the power device LV has three (particularly identically formed) power modules LM arranged one behind the other in a longitudinal direction of the cover plate DP, which is also the longitudinal direction LR of the cooler KL. The three power modules LM are distributed evenly and equally spaced from one another on the surface OF of the cover plate DP, so that they are each located on one of three approximately equally sized surface areas (in Figure 1, a left, a middle, and a right surface area) of the surface OF, each of which occupies approximately one-third of the total surface area of ​​the surface OF.

[0061] Each of the three power modules LM in turn has four power semiconductor switches LH1 and LH2, respectively, which are arranged in pairs in two rows next to each other, so that each of the two power semiconductor switch pairs LH1 and LH2 of each power module LM, viewed in the longitudinal direction LR, is arranged distributed around the longitudinal axis LA of the cover plate DP on the right and left sides of the longitudinal axis LA of the cover plate DP, respectively, as is better shown in Figure 2.

[0062] The four power semiconductor switches LH1 and LH2 of the respective power modules LM each form two positive-voltage-side and two negative-voltage-side power semiconductor switches of two half-bridges connected in parallel to each other in a bridge circuit of the inverter. In this embodiment, all power semiconductor switches LH1 and LH2 are formed, for example, as SiC semiconductor switches.

[0063] Furthermore, the four power semiconductor switches LH1 and LH2 of the respective power modules LM are each arranged in pairs on one of two partial surface areas, which are each distributed to the left and right of the longitudinal axis LA of the cover plate DP and are located on one of the three previously mentioned surface areas (in Figure 1 the left, middle and right surface areas) of the surface OF. For ease of description, a partial surface area of ​​the right surface area of ​​the surface OF, which in Figure 1 is located to the right and thus immediately left of an inlet EL of the cooler (see also Figure 2), is referred to below as the first area B1 and the remaining five partial surface areas of the left, middle and right surface areas together as the second area B2 in order to be able to illustrate the special features of the first area B1 compared to the second area B2 and the technical effect of the cooler KL more simply and clearly.

[0064] The two power semiconductor switches of the power module LM on the left in Figure 1, which are located in the first area B1, are designated below by the reference symbol LH1, while the two remaining power semiconductor switches of the same power module LM and the power semiconductor switches of the two remaining power modules LM are designated below by the reference symbol LH2.

[0065] The inverter further comprises a control circuit including driver circuits (not shown in the figure) for controlling the power electronics device LV or operating the said power semiconductor switches LH1, LH2, which is / are electrically connected via control signal connections (not shown in the figure) to the power semiconductor switches LH1, LH2 of the power electronics device LV or to their control terminals.

[0066] In addition to the cover plate DP already mentioned above, the cooler KL also has a base plate BP which, together with the cover plate DP, encloses a cooling channel KN for the passage of a liquid coolant, such as cooling water, which extends in the longitudinal direction LR of the cooler KL.

[0067] The cooler KL further comprises a coolant inlet EL and a coolant outlet AL (see Figure 2), which are formed on the base plate BP and are arranged next to one another in the longitudinal direction LR at a first longitudinal end E1 of the base plate BP or of the cooling channel KN and thus one behind the other in a transverse direction QR of the cooler KL (see Figure 2).

[0068] The cooler KL also has an insert plate EP, which is arranged in the cooling channel KN between the base plate BP and the cover plate DP and divides the cooling channel KN into a supply flow channel section ZF extending from the coolant inlet EL and thus from the first longitudinal end E1 of the cooling channel KN in the longitudinal direction LR to a second longitudinal end E2 of the cooling channel KN facing away from the first longitudinal end E1, and a return flow channel section RF extending from the second longitudinal end E2 in the longitudinal direction LR to the coolant outlet AL and thus to the first longitudinal end E1. The insert plate EP encloses the supply flow channel section ZF with the base plate BP (at least partially or largely completely or except for openings to be described below) and the return flow channel section RF with the cover plate DP (at least partially or largely completely or except for the openings to be described below).

[0069] The insert plate EP has two through-openings DO at the second longitudinal end E2, which are arranged next to one another in the longitudinal direction LR and together extend in the transverse direction QR over almost the entire width of the cooling channel KN, as illustrated in Figure 2. The through-openings DO serve to conduct the coolant from the supply flow channel section ZF to the return flow channel section RF.

[0070] As can be seen from Figure 2, the insert plate EP further has a return opening RO at the first longitudinal end E1 of the cooling channel KN, which is configured to conduct the coolant from the return flow channel section RF to the coolant outlet AL. The return opening RO extends in the transverse direction QR of the cooling channel KN to the longitudinal axis LA of the cooler KL or the cooling channel KN. In the longitudinal direction LR, the return opening RO has a length or longitudinal extension L2.

[0071] The insert plate EP has a sealing wall (not visible in Figure 2, as this is located below the insert plate EP or between the insert plate EP and the base plate BP) which surrounds the return opening RO at the edges facing away from the coolant outlet AL and extends into the return flow channel section RF up to the base plate BP and thus fluidically separates the return opening RO from the supply flow channel section ZF or seals it fluid-tight.

[0072] The geometry of the cooling channel KL, in particular of the return flow channel section RF, and the positions and shapes of the two through-openings DO located at the second longitudinal end E2 of the cooling channel KL in the transverse direction QR, and the position and shape of the return opening RO located at the first longitudinal end E1 of the cooling channel KL in the transverse direction QR, lead to an asymmetric flow of the coolant in the return flow channel section RF (illustrated in Figure 2 with straight arrows), which in turn results in a region BR of the return flow channel section RF being poorly or barely flowed around by the coolant. This region BR extends in the transverse direction QR between the return opening RO and thus the coolant outlet AL, and a channel side wall SW of the cooling channel KN facing away from the coolant outlet AL in the transverse direction QR.In the longitudinal direction LR, the region BR extends from the first longitudinal end E1 to one third of the total length of the return flow channel section RF and has a length or longitudinal extent L1 which is a maximum of three times the length or longitudinal extent L2 of the return opening RO.

[0073] In this region BR, a turbulent flow region (illustrated in Figure 2 with a circular arrow) can form, similar to a separation bubble, which would be separated from the (generally laminar) main flow of the coolant in the return flow channel section RF, or would be difficult to reach, if the insert plate EP did not have a dead-water opening TO (as one of several passage openings), to be described below. This turbulent flow region is predominantly located in the aforementioned region BR and is referred to as the "dead-water region TG."The dead water area TG leads to poor cooling of the overlying semiconductor switches LH1, which are illustrated in Figure 2 with dashed lines for a better description of the inventive solution and which are located on the area B1 of the surface OF of the cover plate DP, in comparison to the remaining semiconductor switches LH2, which are located above the remaining area of ​​the return flow channel section RF or on the area B2 of the surface OF of the cover plate DP, which are also illustrated in Figure 2 with dashed lines.

[0074] In order to prevent the formation of this dead water area TG, the insert plate EP has the aforementioned dead water opening TO, which is located above the area BR or the dead water area TG to be expected without the dead water opening TO and extends through the insert plate EP and thus fluidically connects the supply flow channel section ZF directly with the dead water area TG to be expected without the dead water opening TO.

[0075] During cooling operation of the cooler KL, a part of the coolant can flow from the supply flow channel section ZF through the dead water opening TO directly to the dead water area TG that would be expected without the dead water opening TO and thus flow through the dead water area TG and can thereby effectively prevent a swirling flow similar to a separation bubble and thus a dead water area from forming or persisting in the aforementioned area BR.

[0076] The insert plate EP further comprises a plurality of bypass openings BO (as further passage openings) which are designed to directly pass further parts of the coolant from the supply flow channel section ZF without flowing through the passage opening DO directly to the return flow channel section RF.

[0077] During cooling operation of the cooler KL, additional portions of the coolant can flow from the supply flow channel section ZF through the bypass openings BO directly into the return flow channel section RF and mix in the middle of the return flow channel section RF with the remaining coolant, which flows over the entire flow path from the supply flow channel section ZF via the through-openings DO to the return flow channel section RF and is relatively warm. This achieves a largely uniform temperature in the coolant in the return flow channel section RF and reduces the overall pressure drop in the cooling channel. To achieve the most homogeneous mixing of the coolant possible in the entire return flow channel section RF, several bypass openings BO are provided, which are (evenly) distributed over the entire surface of the insert plate EP.

[0078] At the respective bypass openings BO and the dead water opening TO, the insert plate EP each has a temperature-controlled valve VT, which is configured to control and / or regulate the coolant flow through the bypass openings BO or the dead water opening TO depending on coolant temperatures in the supply flow channel section and in the return flow channel section (or depending on local coolant temperatures at their respective channel areas around the respective openings BO, TO) or depending on the temperature difference between these temperatures, i.e. to completely block the flow through the corresponding openings BO, TO or to partially or completely release it.

[0079] The valves VT are designed as temperature-sensitive bimetal diaphragm valves.

[0080] With these temperature-controlled valves VT, the entire flow of coolant through the return flow channel section RF can be influenced and controlled or regulated during the (entire) cooling operation of the cooler KL with regard to pressure loss, flow velocity, and flow direction in the return flow channel section. The valves VT change the coolant flows through the respective openings BO, TO continuously and without active external intervention during the (entire) cooling operation of the cooler KL, automatically and (solely) depending on the coolant temperatures in the respective channel areas around these respective openings BO, TO. This means that, during the (entire) cooling operation, an average of the cooling water temperature across the entire return flow channel section RF is achieved and maintained through targeted dynamic cooling water mixing, and the formation of a dead water zone is effectively prevented.This ensures largely homogeneous cooling of the cover plate DP and thus of the power modules LM or power semiconductor switches LH1 or LH2 of all power modules LM arranged on it, despite their placement one behind the other in the coolant flow direction in the return flow channel section RF. On the underside facing the return flow channel section RF, the cover plate DP has a surface-enlarging surface structure with cooler pin fins PF. These are distributed over a surface area of ​​the underside adjacent to the return flow channel section RF and protrude from the cover plate DP into the return flow channel section RF, thus extending in the direction of the insert plate EP.

[0081] The insert plate EP has a flow guide structure on the underside facing the supply flow channel section ZF, which has two flow guide walls extending in the longitudinal direction LR and projecting away from the insert plate EP into the supply flow channel section ZF. The flow guide walls are configured to guide the coolant flowing from the coolant inlet EL or from the bypass channel area UB into the supply flow channel section ZF to the two through-openings DO.

[0082] The base plate BP has a groove-shaped channel structure RN surrounding the plate. Accordingly, the insert plate EP has a wall structure (not shown in the figures) that at least partially surrounds the plate and corresponds to the channel structure RN. This wall structure protrudes into the channel structure RN, thus creating a fluid-tight connection between the insert plate EP and the base plate BP, thus fluid-tightly sealing the supply flow channel section ZF.

Claims

Patent claims 1 . Power electronics cooler (KL) for cooling a power electronics device (LV), comprising: - a base plate (BP) and a cover plate (DP) which together enclose a cooling channel (KN) for conducting a coolant, which extends in a longitudinal direction (LR) of the cooler (KL); - a coolant inlet (EL) and a coolant outlet (AL) arranged in the longitudinal direction (LR) at a first longitudinal end (E1) of the cooling channel (KN); - an insert plate (EP) which is arranged in the cooling channel (KN) between the base plate (BP) and the cover plate (DP) and divides the cooling channel (KN) into a supply flow channel section (ZF) extending from the coolant inlet (EL) to a second longitudinal end (E2) of the cooling channel (KN) opposite the first longitudinal end (E1) and a return flow channel section (RF) extending from the second longitudinal end (E2) to the coolant outlet (AL); - wherein the insert plate (EP) encloses the feed flow channel section (ZF) with the base plate (BP) and encloses the return flow channel section (RF) with the cover plate (DP); - wherein the insert plate (EP) has a passage opening (DO) at the second longitudinal end (E2) for passing the coolant from the supply flow channel section (ZF) to the return flow channel section (RF); - wherein the insert plate (EP) further comprises a passage opening (BO, TO) for passing a part of the coolant from the supply flow channel section (ZF) directly to the return flow channel section (RF); - wherein the insert plate (EP) has a temperature-controlled valve (VT) at the passage opening (BO, TO), which is designed to block or release the coolant flow through the passage opening depending on coolant temperatures in the supply flow channel section (ZF) and / or in the return flow channel section (RF).

2. Cooler (KL) according to claim 1, wherein the passage opening is a bypass opening (BO) for directly passing a part of the coolant from the supply flow channel section (ZF) without flowing through the passage opening (DO) directly to the return flow channel section (DO).

3. Cooler (KL) according to claim 1 or 2, wherein the passage opening is a dead water opening (TO) for directly passing a part of the coolant from the supply flow channel section (ZF) directly to a dead water region (TG) of the return flow channel section (RF).

4. Cooler (KL) according to one of the preceding claims, wherein the valve (VT) is a diaphragm valve.

5. Cooler (KL) according to one of the preceding claims, wherein the valve (VT) is a bimetal valve.

6. Cooler (KL) according to one of the preceding claims, wherein the valve is further configured to block or release the coolant flow through the passage opening depending on the temperature difference between the coolant temperatures in the supply flow channel section (ZF) and in the return flow channel section (RF).

7. Cooler (KL) according to one of the preceding claims, wherein the valve is further configured to block or release the coolant flow through the passage opening depending on local coolant temperatures in the supply flow channel section (ZF) and / or in the return flow channel section (RF) and around the passage opening and / or on the temperature difference between these local coolant temperatures.

8. Cooler (KL) according to one of the preceding claims, wherein the valve is further configured to not release, or partially or completely release, the coolant flow through the passage opening depending on the coolant temperatures in the supply flow channel section (ZF) and in the return flow channel section (RF) and / or on the temperature difference between these coolant temperatures and thus to control or regulate the coolant flow through the passage opening.

9. Power electronics device (LV), comprising: - a power module (LM); - a cooler (KL) according to one of the preceding claims; - wherein the power module (LM) is mounted on a The return flow channel section (RF) is arranged on a surface (OF) of the cover plate (DP) facing away from the return flow channel section (RF) and is in thermal contact with the cover plate (DP).

10. Inverter, comprising: - a power electronics device (LV) according to claim 9; - a driver circuit for operating the power electronic device (LV), which is electrically connected to the power module (LM) via signal connections.

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