Power converter arrangement and method for producing a power converter arrangement

A three-dimensional arrangement for a power converter device, e.g., an inverter or a rectifier, is provided. The switching elements, activation electronics, the load connections of the power converter device are arranged on a carrier device in such a way that defines especially short conduction paths. The components of the power converter device (e.g., all required components), such as switching elements, control electronics, and load connections, are arranged on a common carrier device. The carrier device is simultaneously used as a cooling device for the entire switching device. The power converter device may thereby achieve particularly efficient performance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage Application of International Application No. PCT/EP2014/059037 filed May 5, 2014, which designates the United States of America, and claims priority to EP Application No. 13167816.1 filed May 15, 2013, the contents of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a power converter arrangement and a method for producing a power converter arrangement.

BACKGROUND

Power converter arrangements are electrical circuit arrangements for the conversion of a direct electric current voltage (D.C.) into an alternating current voltage (A.C.) (inverters) and/or for the conversion of an A.C. voltage into a D.C. voltage (rectifiers). Inverters are used, for example, in the field of regenerative energy sources, in order to permit the infeed of a D.C. voltage generated by a photovoltaic installation or similar into an A.C. system. Inverters of this type are also required, for example, for battery-powered standby power supply systems, in which the D.C. voltage delivered by the battery is converted into an A.C. voltage, which can then be fed into the standby grid system. In addition, rectifiers are applied, for example, for the charging of a battery or a battery arrangement which is supplied by an A.C. voltage source. In addition, combinations of rectifiers and inverters are specifically used in electric vehicles. During traveling, for example, a D.C. voltage delivered by a battery is converted into a controlled A.C. voltage, which powers a vehicle drive system. During braking, the electrical drive system then acts as a generator and generates an A.C. voltage which, further to rectification in a power converter circuit, can be used to charge the battery.

In existing power converters, power modules are used which employ a planar arrangement of power semiconductor chips on a substrate, generally of a ceramic material. Accordingly, the printed conductors for the connection of said semiconductor chips are, by definition, also configured in a planar arrangement. Accordingly, the arrangement of printed conductors is restricted to two dimensions. This two-dimensional arrangement is associated, in some cases, with relatively long current paths. Moreover, in some cases, the supply and return conductors surround relatively large surface areas. These two effects are associated with an in-service increase in the stray inductance of a power converter arrangement of this type. This has a negative impact upon the switching performance of the power semiconductors. In these cases, the power semiconductors used, for example diodes or IGBTs (Insulated Gate Bipolar Transistors), have higher switching losses, and heat up significantly as a result. In this case, the cooling circuit will therefore need to be dimensioned to a corresponding magnitude. The capacity of a power converter of this type is therefore less dependent upon the semiconductor chips used than upon the cooling facilities available. The more effective the cooling of the power converter, the higher the capacity available.

SUMMARY

One embodiment provides a power converter arrangement, including a three-dimensional carrier arrangement which has a trapezoidal cross section perpendicular to one spatial direction; and a plurality of switching elements, wherein the plurality of switching elements is arranged on two opposing sides of the carrier arrangement.

In a further embodiment, each of the plurality of switching elements comprises a semiconductor switch and/or a diode.

In a further embodiment, the plurality of switching elements is arranged on the external sides of the carrier arrangement.

In a further embodiment, the carrier arrangement is provided with a hollow interior.

In a further embodiment, a coolant fluid flows through the interior of the carrier arrangement.

In a further embodiment, the switching elements are arranged on an upper surface of a substrate, and an underside, opposite said upper surface of the substrate is arranged on a cooling element.

In a further embodiment, the power converter arrangement also includes a control device which is designed for the control of the plurality of switching elements and is arranged on one further side of the carrier arrangement, wherein the further side of the carrier arrangement connects both sides of the carrier arrangement with the plurality of switching elements.

In a further embodiment, the power converter arrangement also includes a connection device which is designed for the provision of D.C. and/or A.C. voltage connections and is arranged on one side of the carrier arrangement, which connects both sides of the carrier arrangement with the plurality of switching elements.

In a further embodiment, the power converter arrangement also includes a capacitor arrangement which is connected to the connection device.

In a further embodiment, the plurality of switching elements is bonded to the control device and/or to the connection device by means of spring contacts.

Another embodiment provides a method for the production of a power converter arrangement, comprising steps for providing a three-dimensional carrier arrangement, which has a trapezoidal cross section perpendicular to one spatial direction; and arranging a plurality of switching elements on the carrier arrangement, wherein the plurality of switching elements is arranged on two opposing sides of the carrier arrangement.

DETAILED DESCRIPTION

Embodiments of the present invention provide an efficiently coolable circuit arrangement with an improved switching performance.

Some embodiments provide a power converter arrangement with a three-dimensional carrier arrangement which has a trapezoidal cross section perpendicular to one spatial direction; and a plurality of switching elements, wherein the plurality of switching elements is arranged on two opposing sides of the carrier arrangement.

Other embodiments provide a method for the production of a power converter arrangement, comprising steps for the provision of a three-dimensional carrier arrangement which was a trapezoidal cross section perpendicular to one spatial direction; and the arrangement of a plurality of switching elements on the carrier arrangement, wherein the plurality of switching elements is arranged on two opposing sides of the carrier arrangement.

An idea underlying some embodiments is that all the requisite structural elements of a power converter arrangement should be arranged on a three-dimensional carrier, such that the efficient exploitation of all the external sides of said carrier is achieved. In conventional two-dimensional arrangements, only an upper side and an underside of the two-dimensional carrier are available for accommodation purposes. Given that, under normal circumstances, for the purposes of the requisite cooling, a cooling element must be fitted to one of these two sides, only one side of conventional power converter arrangements is available for the accommodation of components. Conversely, as a result of the three-dimensional configuration of the carrier, a plurality of external sides is available, all of which can be used to accommodate components of the power converter arrangement.

This three-dimensional power converter arrangement has a significant advantage, in that a carrier arrangement according to the invention also serves as a cooling element. Accordingly, the efficient cooling of the switching elements, the requisite control electronics and the power feeds can be achieved.

A further advantage is provided in that, in the three-dimensional arrangement according to the invention, the spatial clearance between the control electronics and the power electronics connections is very small. Accordingly, very short conduction paths between the control electronics and the power electronics can be achieved. This results in correspondingly small conductor inductances, which impacts positively upon the switching performance and the resulting switching losses in the power converter arrangement.

It is also advantageous that power-carrying connections in the power converter arrangement can also be configured with very short current paths. Specifically, the three-dimensional configuration of the power converter arrangement permits a requisite intermediate circuit capacitor to be guided very close up to the semiconductor switching elements.

According to one embodiment, each of the plurality of switching elements comprises a semiconductor switch and/or a diode. Semiconductor switches including, for example IGBTs or MOSFETS, specifically in combination with diodes, have proven to be effective in power converter arrangements of this type.

According to a further embodiment, the plurality of switching elements is arranged on the external sides of the carrier arrangement. The switching elements therefore face outwards from the carrier arrangement. Accordingly, no further protective measures, such as the additional isolation of the switching elements, are required.

According to a further embodiment, the carrier arrangement is provided with a hollow interior, and a coolant fluid preferably flows through the interior of the carrier arrangement. In a carrier arrangement thus configured, specifically a fluid-cooled carrier arrangement, a particularly efficient cooling of the power converter arrangement is possible. This also results in a particularly efficient power converter arrangement.

According to a further embodiment, the switching elements are arranged on an upper surface of a substrate, wherein the underside of the substrate, opposite said upper surface of the substrate, is arranged on a cooling element. In this way, the particularly efficient dissipation of the thermal energy of the switching elements to the carrier arrangement is possible, for the purposes of cooling.

In a further embodiment, the power converter arrangement also comprises a control device, which is designed for the control of the plurality of switching elements, wherein the control device is arranged on one further side of the carrier arrangement, and the further side of the carrier arrangement connects both sides of the carrier arrangement with the plurality of switching elements. By the arrangement of the control device between the switching elements, a connection of the control device to the switching elements can be achieved by means of particularly short and low-inductance conduction paths. This has a highly favorable impact upon the switching performance and the resulting switching losses associated with the power converter arrangement.

In a further embodiment, the power converter arrangement also comprises a connection device, which is designed for the provision of D.C. and/or A.C. voltage connections, wherein the connection device is arranged on one side of the carrier arrangement, which connects both sides of the carrier arrangement with the plurality of switching elements. Preferably, this side fitted with the connection device is arranged opposite the side fitted with the control device. In this way, the power connections of the power converter arrangement can also be configured with a particularly short length.

In a further embodiment, the power converter arrangement also comprises a capacitor arrangement, which is connected to the connection device. In this way, the capacitor arrangement, for example an intermediate circuit capacitor in a power converter arrangement, can be guided very close up to the switching elements. This has an advantageous impact upon the switching performance of the power converter arrangement.

According to a specific embodiment, the plurality of switching elements is connected to the control device and/or the power converter device by means of spring contacts. The use of spring contacts for the connection of the control device or the connection device permits a particularly straightforward and rapid contact bonding of the individual components.

FIG. 1shows an oblique view of a carrier device10for a power converter device according to the invention. The external form of said carrier device10is approximately equivalent to a prism with parallel upper and undersides, lying in the x-z plane. The upper side12and the lower side11are preferably configured in the form of a rectangle. To this end, the edges which run parallel to the z-axis are preferably of equal length, whereas the outer edges, which run parallel to the x-axis, are preferably shorter on the upper side12than on the lower side11. Accordingly, the front side13and the rear side14of the carrier device10are configured in the form of an equal-sided trapezium. The front side13and the rear side14are preferably arranged in parallel to the x-y-plane. However, it is also conceivable that the front side13and the rear side14are at least slightly inclined in relation to said x-y-plane. Finally, the carrier device10is also provided with two lateral surfaces15and16, which respectively connect the lower side11to the upper side12.

The carrier device10is preferably provided with a hollow interior. In this way, a coolant fluid can flow through the interior of the carrier device10. Accordingly, this permits the efficient cooling of the power converter device. Alternatively, it is also conceivable that the carrier device10has one or more interior cooling ducts, through which a coolant fluid can flow for the cooling of the power converter arrangement. Said cooling ducts may be configured, for example, with a meandering or labyrinthine structure. The use of a coolant fluid for cooling purposes ensures exceptionally efficient cooling. However, it is also conceivable in addition that the interior of the carrier device10can be cooled by a gas, for example air or similar.

The external sides of the carrier device10, specifically the lower side11, the upper side12and the two lateral surfaces15and16are preferably configured as closed surfaces such that, on said sides, no escape of coolant fluid is possible. However, the outer surfaces may also be provided with corresponding openings (not represented), by means of which cooling ribs on the components fitted to the carrier arrangement10can penetrate the interior of the carrier device. By this arrangement, the particularly effective cooling of the cooling ribs can be achieved. In this case, however, attention must be paid to providing a leak-tight seal on the openings during operation.

On the front side13and/or the rear side14, openings may also be provided for the inlet/outlet of a coolant fluid (not represented). However, according to requirements, said openings for the inlet/outlet of the coolant fluid may also be arranged on another side of the carrier device10. The carrier device10may also be provided with an appropriate attachment device (not represented) which permits the attachment of the further components of the power converter device to the carrier device10and, where applicable, also permits the appropriate electrical contact bonding of the individual components.

FIG. 2shows a cross section of a carrier device10in the x-y-plane, perpendicularly to the z-axis. In this section of the x-y-plane, the carrier device10has a trapezoidal cross section. The lower side11and the upper side12form the two parallel sides of the trapezium in this case, whereas the legs of the trapezium are formed by the two lateral surfaces15and16. The trapezium is preferably equal-sided, i.e. the two legs of the trapezium are of equal length. A carrier device10with a trapezoidal cross section of this type is particularly advantageous for the arrangement of the components of the power converter device. In principle, however, it is also conceivable that the device10has a cross section which differs from an equal-sided trapezium.

One or more switching elements20are arranged on each of the two lateral surfaces15or16inFIG. 2, which correspond to the two legs of the trapezium. Preferably, such switching elements20are arranged on both external sides15and16of the carrier device10. An exceptionally uniform thermal distribution during the operation of the power converter arrangement is achieved accordingly. Although an equally symmetrical distribution of the switching elements20on the two external sides15and16of the carrier arrangement permits an exceptionally uniform and advantageous distribution, it is also conceivable, for specific applications, that the switching elements20should be arranged on only one of the two external sides15and16, or that more switching elements20should be arranged on one of the two external sides15and16than on the opposite lateral surface.

Each of the switching elements20is preferably provided with a semiconductor switching element20aand with a diode20b. The semiconductor switching element20ais preferably an insulated gate bipolar transistor (IGBT) or a MOSFET. However, other types of switching elements, specifically semiconductor elements, are also possible. The additionally-provided diode20bpreferably operates as a free-wheeling diode.

The switching elements20are preferably arranged in this case on a carrier substrate21which, in addition to the semiconductor switching elements20aand the diodes20b, also has corresponding printed conductors for the connection of the components. Preferably, the substrate21carrying the switching elements20is arranged in this case on the carrier device10such that the switching elements20face outwards from the carrier device. Accordingly, the substrate21acts simultaneously as an insulating medium between the switching elements20and the carrier device10. As the switching elements20are therefore fitted to the carrier device10in an insulating arrangement, no further insulation on the outward-facing side of the carrier device10is necessary.

In the interests of a more effective dissipation of thermal energy generated in the switching elements20during the operation of the power converter arrangement, the lower side of the substrate21may be provided with a cooling element22. Said cooling element may be configured, for example, as a structure with a large surface area, for example in the form of cooling ribs, which permits particularly effective heat dissipation. To this end, the switching elements20provided with the cooling elements22are arranged on the carrier device10such that the cooling elements22project into the interior of the carrier device10. During operation, accordingly, the cooling element22is surrounded and cooled by the flux of the coolant fluid in the interior of the carrier device10. In this way, a particularly effective dissipation of the thermal energy generated can be achieved, thereby enhancing the efficiency of the power converter arrangement.

For the connection of the switching elements20, and the connection of the switching elements20with the other components of the power converter device, numerous known and, in some cases, innovative connection technologies are possible. For example, the switching elements20may be contact-bonded by means of a conventional wire-bond connection method. Alternatively, connection by means of SiPLIT technology (Siemens Planar Interconnect Technology) is also possible. In addition, all other known connection technologies are also possible including, for example, screw connections, contact bonding by means of spring contacts33, etc.

The lower side11of the carrier device10is provided with control electronics40for the control of the switching elements20. The control electronics40are arranged on the lower side11of the carrier device10such that, firstly, thermal contact is established between the control electronics40and the device10and, secondly, the control electronics40are electrically isolated from the carrier device10. In this way, thermal energy from the control electronics40, which is generated during the operation of the power converter device, can also be dissipated by the carrier device10. The outer sides of the control electronics40are positioned in this case in the immediate vicinity of the outer sides of the switching elements20. Accordingly, the connection paths between the control electronics40and the switching elements20are exceptionally short. As a result, only very small conductor inductances are generated. In consequence, in the arrangement according to the invention, the switching elements20can be controlled by the control electronics40with exceptional precision. The accurate and rapid switching performance also generates reduced switching losses, with a consequent reduction in the thermal loading of the power converter arrangement.

The upper side12of the carrier device10which lies opposite the lower side11of the control device40is also provided with a connection device30for the contact bonding of the switching elements20with the load connections. The function of the connection device30is firstly the connection of the A.C. voltage connections, and secondly also the connection of the D.C. voltage connections. To this end, the connection device30is preferably configured as a multi-layer busbar, as described in greater detail below.

Said connection device30is furthermore also associated with a capacitor device31. For example, the capacitor device31may be comprised of one or more intermediate circuit capacitors, of the type which are customarily used in power converter devices. As a result of the three-dimensional arrangement of components around the carrier device10, the capacitor device31can be guided very close up to the switching elements20in this case. Accordingly, only very short conduction paths, with correspondingly small conductor inductances, arise between the capacitor device31and the switching elements20. This also impacts advantageously upon the operation of the power converter device according to the invention.

The connection device30is furthermore also arranged on the carrier device10such that thermal energy from the connection device30can be effectively dissipated by the carrier device10. As a result of this cooling of the connection device30, said connection device30can also be configured with smaller dimensions, with no resulting increase in the thermal loading of the current-carrying load connections.

FIG. 3shows a cross sectional view of a carrier device10and further components of a power converter arrangement according to the invention. Again in this case, one or more switching elements are arranged respectively on the two outer sides15and16of the carrier device10. Here again, a connection device30with a capacitor device31is arranged on the upper side12. The control device40is arranged on the lower side11of the carrier device10. The control device40is secured in place by one or more retaining elements51. The carrier device10is also secured in place by one or more retaining elements52. The retaining elements51for the retention of the control device40, and the retaining elements52for the retention of the carrier device10, are preferably secured in place by common baseplate50, for example a housing wall or similar. Accordingly, a space is formed between the retaining elements51of the control device and the retaining elements52of the carrier device, which is sufficient to accommodate the components of the control device40.

FIG. 4shows an overhead view of a power converter device according to the invention, representing an overhead view in the x-z-plane. In the representation shown inFIG. 4, a load connection32is respectively arranged on the left-hand and/or right-hand outer side, by means of which the connection device30may be connected to an external A.C. voltage connection. By means of said load connections32, the power converter device according to the invention may therefore be connected, for example, to an external A.C. grid system, an A.C. consumer or an A.C. voltage source. To this end, all phase connections for the connection of the A.C. voltage are preferably brought out on both sides respectively. Alternatively, it is also possible that the A.C. connection is brought out on one side only, or that the individual phases are brought out on different sides, In principle, it is also conceivable in addition, where required, that the D.C. voltage connections of the power converter device should also be brought out laterally to the load connections32. For example, the A.C. voltage connections may be brought out on one side, for example to the left, and the D.C. voltage connections may be brought out on the other side, for example to the right. Other variations for the bringing-out of the load connections are also possible.

Preferably, however, the D.C. voltage connections of the power converter arrangement according to the invention are configured directly on the capacitor device31, i.e. on the corresponding intermediate circuit capacitors.

As viewed from the top or bottom to the center of the image, the following components are represented inFIG. 4: in the outermost area, i.e. at the very top and the very bottom, the control connections for the switching elements are arranged. The corresponding semiconductor switches I1to I6are adjacent thereto. This gives rise to exceptionally short conductor routes for the control of the respective switching elements. Progressing further from the bottom/top towards the center of the image, the corresponding diodes D1to D6are next in sequence. These are followed by the contact zones for the contact bonding of the switching elements20to the contact zones of the connection device30. Finally, the connection device30is arranged in the central mid-zone. The connection points for the contact bonding of the switching elements to the connection device30are arranged such that the conductor paths between the switching elements and the connection points are as short as possible. In consequence, inFIG. 4, the semiconductor switches I1and I4, together with the diodes D1and D4, are very close to the connection point for the conductor L1, the semiconductor switches I2and I5, together with the diodes D2and D5, are very close to the connection point for the conductor L2, and the semiconductor switches I3and I6, together with the diodes D3and D6, are very close to the connection point for the conductor L3. Moreover, in the interests of more uniform thermal loading, the switching elements and connection points for the respective phases of the A.C. voltage are arranged on the two sides of the carrier device10in an offset pattern.

In this arrangement, connection between the switching elements20and the connection device30is effected, for example, by means of conventional bond connection technology, by means of suitable screw connections or, where applicable, by the use of spring elements33for contact bonding. In this regard, for example, the abovementioned SiPLIP technology has also proven to be particularly advantageous. Spring elements permit exceptionally straightforward and rapid fitting and contact bonding in this case. However, on the grounds of their limited rather contact surface in the spring contact area, spring elements are preferably appropriate for lower current ratings. The contact bonding of the control connections of the switching elements20with the control device40proceeds analogously with the corresponding contact elements34.

FIG. 5shows a cross section of a connection device30and semiconductor elements20connected to the connection device30. To this end, the connection device30is configured as a multi-layer busbar. A busbar of this type is comprised of a plurality of current-carrying metal buses which are mutually separated by electrically-insulating spacers. In the example represented, the connection device30, considered from bottom to top, is firstly comprised of a number of current-carrying layers for the A.C. voltage connections. These layers are respectively separated from one another by an appropriate insulating medium. Current-carrying layers for the D.C. voltage, also separated by insulating media, are arranged immediately above. This arrangement provide an exceptionally compact arrangement of all the requisite power connections. A current-carrying layer which is to be bonded to a connection point with a switching element20is routed upwards in this case by an appropriate through-connection arrangement (not represented) and is bonded to the switching elements20by means of appropriate contact elements.

The switching elements20, which are comprised, for example, of semiconductor switching elements20aand diodes20b, are arranged on an appropriate insulating carrier material21. For example, this may be a ceramic carrier material. Said carrier material is configured for the dissipation of heat generated, preferably to a further heat sink22. In the interests of improved thermal contact, a thermally conductive paste or similar—not represented—may be applied between the substrate21and the heat sink22.

FIG. 6shows a schematic representation of a method for the production of a power converter device according to one embodiment of the present invention. To this end, in a first step110, a three-dimensional carrier device10is firstly provided, which has a trapezoidal cross section perpendicular to one spatial direction Z. Thereafter, in step120, a plurality of switching elements20is applied to the carrier arrangement10, wherein the plurality of switching elements20is arranged on two opposing sides15and16of the carrier arrangement10.

The production method for a power converter device according to the invention is again represented in detail inFIG. 7. In the upper part of this figure, a switching element20comprised of a semiconductor switch20aand a diode20bis firstly bonded with a cooling element22. In the stages represented thereunder, as shown in the central part, the preconfigured switching elements20with the cooling elements are arranged on the carrier device10. To this end, the carrier device10is provided, on its left-hand and right-hand sides, with appropriate recesses in each case for the accommodation of the cooling elements22of the switching elements20. In addition, a capacitor device31is bonded with a connection device30(represented on the left) and a control device30is fitted to an appropriate retaining device51(represented on the right). As represented in the lower part of the diagram, the carrier device10with the switching elements20fitted is then applied to the retaining device52and the connection device30with the capacitor device30fitted is also bonded with the carrier device10. Finally, switching elements20are electrically bonded with the control device40on one side, and electrically bonded with the connection device30on the other side.

In summary, the present invention relates to a three-dimensional arrangement for a power converter device, such as an inverter or a rectifier for example. For this purpose, the requisite switching elements, control electronics and load connections are arranged on a carrier device such that exceptionally short conduction paths are achieved. In some embodiments, all the requisite components, such as switching elements, control electronics and load connections, are arranged on a common carrier device. Said carrier device is simultaneously used as a cooling device for the entire switching device. An exceptionally efficient operation of the power converter device is achieved accordingly.