DE19646396C2 - Power semiconductor module for different circuit variants - Google Patents

Description

The invention describes a power semiconductor module of power electronics, in particular Current converter, which is inexpensive for a so-called multivariable structure. Power semiconductor modules are known several times from the literature. As the Technology and finding new solutions take two aspects in the design of Power semiconductor modules use the entire research content in this industry. On the one hand, the procedural steps must always be more efficient, which means that they should have an ever increasing level of automation. The stake Correspondingly inexpensive and quality-oriented materials with the additives of a good one Automatic processability is a prerequisite.

On the other hand, there are always more extensive requirements for reliability and Wide range of applications with minimized space and volume requirements. The variety of Circuit variants are opposed to automation unfavorably and contrary, which is why multivariable designs must be looked for in order to minimize To be able to implement a maximum range of component types in the best quality.  

In DE-OS 15 64 867 and DE-PS 40 39 037, methods are exemplified Production of electronic components of the performance class presented. This procedure are equally suitable for building complete power semiconductor modules.

The state of the art has excellent modules in terms of quality. The Insulation technology using aluminum oxide plates coated with copper on both sides (DCB ceramic) with today's chip technology and a low-inductance structure has a remarkably good one Stand achieved because of the electrical insulation ability, the good break resistance and very good Thermal conductivity represent very valued properties for this purpose.

All of the previously mentioned modules according to the prior art are the lack of flexibility their use as only customer-specific modules with predominantly low Own production volume. The individual production of the small quantities per type is complex and inexpensive. Rational processes for their production fail due to the low utilization of the equipment required for automation.

EP 0 750 345 A2 presents a power semiconductor module that can be flexibly connected. Various circuit variants are achieved in this way on a single base plate, that a plurality of conductor tracks on the base plate only as conductor track sections are available and these for the different circuit variants by means of bond connections be connected differently.

The present invention has for its object to design a power module so that it is possible in the ability to implement a wide variety of circuit variants from standard components (esp. identical insulation ramiken simple and low induction can be.

This task is accomplished with a power semiconductor module according to the Features of claim 1 solved, further advantageous developments are in the Subclaims called.  

The invention encompasses the variety of power semiconductor modules for example in the form of converters (for single and three-phase current input), for DC chopper, for individual switches (some with different freewheeling diodes Interconnections), for half bridges, for single and three phase full bridges (partly also with Brake actuators) and for asymmetrical half bridges various individual activities in the Manufacturing process.  

The internal circuitry of the circuit breakers (mainly IGBT and MOSFET chips enforced) with each other and with the required freewheeling diode chips can be made flexible by different programs of the automatically working Bonding devices can be made possible, with the same basic position of the chips Both small and larger geometries of the chips can be used. The Sheathing the internal circuit elements through the housing enables variable options for the external connection of the electrical connections. All technological Individual steps of module assembly have been redefined and changed with the invention.

The structure of modules that can be assigned to the prior art contains the premise that that large-scale chips are used as circuit breakers for large outputs, this one Solution is in favor of an optimized distribution of the power loss generating Leave circuit breaker to improve heat flow. Smaller chips in one Positioned larger quantities allow a much better temperature distribution on the DCB ceramics and consequently a greater cooling capacity of the cooling surface.

This makes it possible to have a larger packing density for circuit breakers in the same area to provide. This in turn forces the available areas for thermal contact the semiconductor switch relative to the total available with copper To enlarge the area of the insulating ceramic. So it was necessary to state of the art to change the associated contacting of the main power connections in principle. By Butt soldering of every single main current conductor realizes this requirement.

According to the invention, the automation-friendly design of the module structure set one if possible, uniform geometric design of the conductor line distribution of the Target copper layer on the component side of the insulating ceramic. With just one form of Design of the insulating ceramics used for all modules with the above This problem and a low-inductance internal structure were solved for operational purposes. Same Requirements arose in the geometrical shape of the main power connections. With only one shape can be formed by blunt soldering on the copper layer of the DCB ceramic 24 different positions on the copper surfaces of the insulating ceramics electrically contacted become.  

The redesign of the housing allows the use of a single drawing part for everyone in production possible and necessary circuit variants. A matching redesign only of a single module cover ultimately leads to a unification of the outer ones Design by means of a drawing part with a universal and multivariable area of application.

The invention is explained by way of example below:

Fig. 1 outlines a view of a semiconductor power module according to the invention.

Fig. 2 shows the top view of a module cover.

Fig. 3 shows a soldered "torso" in plan view (a circuit variant).

Fig. 1 outlines a view of an inventive power semiconductor module. Round openings are incorporated in the four corners on a flat base plate ( 21 ), preferably formed from copper or aluminum, in order to be able to secure the housing by means of hollow rivets ( 29 ). The insulating ceramics ( 22 ) are soldered onto this base plate ( 21 ), on which the power semiconductor switches, free-wheeling diodes, other necessary components and power connections are soldered in one go.

The cut district shows the Fig. 1 shows the location of one of the Stumpflötstellen (23) of the main power terminal strip (24). The filling is indicated with an insulating silicone casting ( 25 ), which was filled into the housing ( 26 ) after it was glued to the base plate ( 21 ). The housing is covered by a cover ( 27 ), as is explained in more detail in FIG. 2. In position ( 28 ), a pre-stamped hexagon recess with a cylindrical blind hole can be seen; these designs are intended for receiving a fastening nut for screwing the electrical main current conductors to the electrical connecting lines.

A uniformly designed auxiliary power connection lug ( 30 ) provides all of the required control module signals of the circuit breakers with low inductance for direct or indirect contact with the control unit. Here, a stable contact can be secured very advantageously by means of a flexible printed circuit board.

Fig. 2 shows the plan view of a module cover ( 27 ). The positions (1) to (6) are fixed and raised in the housing material in order to ensure that the main current connection lugs ( 24 ) for a secondary connection to the intermediate circuit or the connection are not mistakenly assigned To be able to carry out power supply or to the load. In the six fields (1) to (6), twelve differently positioned connecting lugs ( 24 ) can be guided through cover openings ( 20 ) and fixed.

After the connection tabs ( 24 ) have been passed through the cover openings ( 20 ) on the assembly side, they are angled to 90 ° in such a way that they lie flat parallel to the surface of the cover ( 27 ) in the respectively required field (1) to (6). Before bending, a nut was deposited in the hexagon recess ( 28 ), in the field (1) to (6) of which there is a connection plate assignment according to the assembly instructions of the specific module. With this construction of the cover ( 27 ), six connecting lugs ( 24 ) can be provided in a multivariable manner from the 24 possible positions on the DCB ceramics ( 22 ). In this way, multiple contacting at high current loads, as well as the connection of different circuits, can be easily implemented.

In positions ( 7 ) to ( 18 ) bushings for receiving all necessary auxiliary connection lugs ( 30 ) are provided in the cover. The numbering is embossed in the same way from the lid material during its manufacture in order to ensure permanent, unambiguous identification. The assignment in the individual concrete module configurations can be gate connections when using MOSFET as a circuit breaker or as basic connections when using IGBT in the same function, but also auxiliary emitters or auxiliary source connections for controlling the Act power semiconductor switches.

Fig. 3 shows a soldered "torso" in plan view in a circuit variant. As an example, a module with four DCB ceramics ( 22 ) is built from this torso. These four ceramics ( 22 ) are connected to one another in a circuit-appropriate manner by bonding ( 34 ). Each ceramic ( 22 ) has identically structured copper surfaces. These copper surfaces are electrically insulated from one another in order to be able to perform various electrical functions.

The surface ( 35 ) is designed for soldering the circuit breakers ( 31 ) with the closely adjacent freewheeling diodes ( 32 ) required in the commutation circuit of the circuit arrangement, which at the same time results in very good thermal coupling with one another and, as a result, the same electrical behavior.

Furthermore, this surface ( 35 ) has soldering islands ( 33 ) for the optional material connection of the connection tabs ( 24 ), which are not shown here. Another copper surface ( 36 ) offers the possibility of establishing internal connections between the circuit breakers ( 31 ) with one another, with free-wheeling diodes ( 32 ), with other components or copper bonding surfaces by bonding. On this surface ( 36 ) there are also soldering islands for connecting lugs ( 24 ) for main current connections and also soldering points for auxiliary connections ( 37 ).

A third, centrally located on the DCB ceramic ( 22 ) and electrically isolated from the aforementioned two copper surfaces ( 35 , 36 ) is for the application of diodes or resistors ( 38 ), also thermistors or other SMD components, depending on the specific Circuit requirements and corresponding soldering pads ( 37 ) provided. Automatic assembly and rational soldering and bonding is made possible by this inventive configuration.

The state-of-the-art process steps for housing gluing and Pouring with a silicone rubber are still necessary for the production of the functionality required. The prior art hard potting made of epoxy resins is however, no longer necessary, because the inventive construction ensures a stable Fixing of all structural parts under mechanical and thermal stress as well as a hermeticization towards environmental influences.

Claims (9)

1. power semiconductor module of high packing density for different circuit variants consisting of base plate ( 21 ), at least two identical electrically insulating substrates ( 22 ) with power semiconductor components ( 24 , 31 , 32 ) to be cooled and a housing ( 26 ) with a cover ( 27 ),
wherein these substrates ( 22 ) are interconnected in a circuit-compatible manner,
as well as soldering islands ( 33 ) at different positions of the respective substrates ( 22 ) for the at least one power connection lug ( 24 ) for the cohesive attachment of the power supply,
as well as a symmetrical cover ( 27 ) which has a plurality of bushings ( 20 ) for all possible positions of the power connection lugs ( 24 ). 2. Power semiconductor module according to claim 1, characterized in that the different circuit variants modules for different purposes, such as Converters, DC choppers, single switches, half bridges or full bridges. 3. Power semiconductor module according to claim 1, characterized in that the base plate ( 21 ) is formed from copper or aluminum and is designed on the surface so that it is solderable on one side for a material connection with a multiple of the insulating ceramic ( 22 ) and the parallel surface or both sides is suitable for material-flush contact with the other structural parts, such as heat sinks and insulating ceramics. 4. Power semiconductor module according to claim 1, characterized in that the substrates ( 22 ) consist of aluminum oxide with a copper coating on both sides, of which one side, the mounting side, is structured in the copper surface so that at least three different and mutually electrical in the flat geometry insulated partial areas are formed. 5. Power semiconductor module according to claim 1, characterized in that the main power connection plate ( 24 ) is formed from copper, several times during the construction of a module with the or the insulating ceramics ( 22 ) is integrally connected and has training that for the compensation of thermal changes in geometry are suitable. 6. Power semiconductor module according to claim 1, characterized in that the cover ( 27 ) in addition to the bushings ( 20 ) for main power connection lugs ( 24 ) has bushings (7 to 18) for auxiliary power connection lugs ( 30 ), with all lead-through positions being numbered consecutively. 7. Power semiconductor module according to claim 1, characterized in that transistors of the power class in the form of IGBT or MOSFET are used as power semiconductor components ( 31 ). 8. Power semiconductor module according to claim 1, characterized in that additional freewheeling diodes are used as power semiconductor components ( 32 ) which are geometrically closely adjacent to the commutating circuit breakers ( 31 ) on the respective insulating ceramic ( 22 ) soldered in a circuit-correct position. 9. Power semiconductor module according to claim 1, characterized in that only a casting compound ( 25 ) made of silicone rubber is used for the mutual insulation of the internal module structures, which at the same time ensures the hermeticization and permanent protection against moisture and other environmental pollution.