DE102019210192A1 - Cooling of electrical components - Google Patents

Abstract

The invention specifies an electrical system (10) which has: a heat sink (1) with an open cooling channel (1.1) through which a coolant (1.2) can flow, - a power semiconductor component that partially covers the cooling channel (1.1) ( 2.1) having power module (2) and a driver circuit device (3), the driver circuit device (3) covering the open remainder of the cooling channel (1.1) in such a way that the driver circuit device (3) can be cooled by the coolant (1.2) flowing past also specifies an associated method for cooling and a power converter and a vehicle with such an electrical system.

Description

Field of invention

The invention relates to an electrical system, in particular for a power converter, with a heat sink that has an open cooling channel through which a coolant flows, with a power module that partially covers the cooling channel and having power semiconductor components, and with a driver circuit device. The invention also relates to an associated method for cooling the electrical system as well as a power converter and a vehicle with such an electrical system.

Background of the invention

Driver circuits are used to control the power semiconductor components in power modules, for example in converters. These are implemented according to the state of the art on organic circuit boards and connected to the power module via solder, spring or press contacts. This so-called driver board is usually connected relatively poorly to the cooling system of the power module. The driver board is only cooled via the control connections or screw connections.

1 shows a sectional view through such an electrical system 10 , in which a power module 2 on a heat sink 1 sits. The power module 2 is about contact elements 3.3 with a driver circuit device 3 electrically connected.

In the case of fast-switching power semiconductor components, a very low-inductance or low-resistance connection of the driver board to the power semiconductor components is advantageous in order to be able to achieve fast switching speeds. The driver circuit must therefore be installed very close to the power module, which also reduces the free volume of the converter.

However, this requires a very temperature-stable driver circuit, since the fast-switching electronic components, based on SiC or GaN, will in future be operated at temperatures above 150 ° C. The resulting waste heat from the power semiconductor components can lead to critical temperatures on or in the driver board due to convection and radiation. Furthermore, the requirement for miniaturization (i.e. tightly packed circuits on the board) also leads to hotspots on the driver circuit.

It is known to arrange the circuit layout on driver boards in an equalized manner in accordance with the thermal load on the components and to install intermediate layers of copper in order to enable a large-area thermal spread for free convection.

The cooling often takes place relatively unspecifically via the fastening screws on the housing or on a cooling plate. To make matters worse, the thermal connection through the organic material of the driver board as insulation is relatively low.

Summary of the invention

It is the object of the invention to provide a solution by which the cooling of a driver circuit device for power modules in, for example, converters is improved.

The invention results from the features of the independent claims. The dependent claims relate to advantageous developments and refinements. Further features, possible applications and advantages of the invention emerge from the following description.

In one aspect of the invention, a driver circuit device is implemented on a ceramic multilayer substrate (e.g. HTCC, LTCC), which is used for cooling as an end plate in an open cooling channel of a heat sink and is firmly connected to the heat sink.

In a further aspect of the invention, additional ceramic cooling structures, such as cooling ribs (= pin fins), can improve the heat transfer between the driver circuit device and a coolant.

In a further aspect of the invention, corresponding metallizations or metal inlays in the ceramic multilayer substrate or around the multilayer substrate, etc. welded or soldered connections can also be realized.

Depending on the spatial orientation, the driver circuit is contacted with the power module of the electrical system via spring contacts, plug connectors or bond wires.

• - eine gute mechanische Festigkeit und Steifigkeit, wobei Stützverschraubungen nicht erforderlich sind,
• - eine hohe Temperaturfestigkeit und eine kompakte Bauweise,
• - einen kleinen thermischen Ausdehnungskoeffizienten und daher eine hohe Lebensdauer,
• - eine sehr gute Wärmeleitfähigkeit,
• - eine hohe chemische Beständigkeit und Korrosionsbeständigkeit gegenüber jeglicher Art von Kühlmittel,
• - eine hohe Kriechstromfestigkeit im Vergleich zu organischen Leiterplatten, was die Zuverlässigkeit erhöht,

und

• - eine Möglichkeit einer 3D Geometrie durch additive Herstellung der HTCC/LTCC, beispielsweise sind dadurch komplexe Kühlstrukturen auf der Substratunterseite möglich.

The invention has the following advantages:

• - a good mechanical strength and rigidity, whereby support screw connections are not required,
• - a high temperature resistance and a compact design,
• - a small thermal expansion coefficient and therefore a long service life,
• - very good thermal conductivity,
• - high chemical resistance and corrosion resistance to any type of coolant,
• - high tracking resistance compared to organic circuit boards, which increases reliability,

and

• - a possibility of a 3D geometry through additive production of the HTCC / LTCC, for example complex cooling structures are possible on the underside of the substrate.

• - einen Kühlkörper mit einem offenen Kühlkanal, durch den ein Kühlmittel strömbar ist,
• - ein den Kühlkanal teilweise abdeckendes, Leistungshalbleiterbauelemente aufweisendes Leistungsmodul und
• - eine Treiberschaltungsvorrichtung, wobei die Treiberschaltungsvorrichtung den offenen Rest des Kühlkanals derart abdeckt, dass die Treiberschaltungsvorrichtung durch das vorbeiströmende Kühlmittel entwärmbar ist.

The invention claims an electrical system comprising:

• - a heat sink with an open cooling channel through which a coolant can flow,
• - A power module that partially covers the cooling duct and has power semiconductor components
• a driver circuit device, the driver circuit device covering the open remainder of the cooling channel in such a way that the driver circuit device can be cooled by the coolant flowing past.

In one development, the power module can have first cooling ribs protruding into the cooling channel. This improves the heat dissipation by reducing the thermal resistance along the path from the heat source to the heat sink.

In a further refinement, the driver circuit device can have a ceramic multilayer substrate which forms a cohesive cover of the cooling channel. This also improves the cooling of heat-emitting components.

In a further embodiment, the ceramic multilayer substrate can have second cooling ribs projecting into the cooling channel, whereby the cooling is also improved.

In a further refinement, the coolant flows first past the power module and then past the driver circuit device, or vice versa.

In a development, the ceramic multilayer substrate can have a metallization or a metal insert.

The invention also claims a method for cooling an electrical system, wherein a coolant flowing in a cooling channel first flows past a power module of the electrical system having power semiconductor components and then past a driver circuit device of the electrical system, or firstly past the driver circuit device and then past the power module.

The invention also claims a power converter, preferably a converter, with an electrical system according to the invention.

A converter is referred to as a converter, which generates an alternating voltage with changed frequency and amplitude from an alternating voltage or direct voltage. Converters are often designed as AC / DC-DC / AC converters or DC / AC converters, with an output AC voltage being generated from an input AC voltage or an input DC voltage via a DC voltage intermediate circuit and pulsed semiconductors.

The invention also claims a vehicle, in particular an aircraft, with a power converter according to the invention for an electric or hybrid-electric drive.

A vehicle is understood as any type of means of locomotion or transport, be it manned or unmanned. An aircraft is a flying vehicle.

• - einen durch den Stromrichter mit elektrischer Energie versorgten Elektromotor und
• - einen durch den Elektromotor in Rotation versetzbaren Propeller.

In a further development, the vehicle has:

• - An electric motor supplied with electrical energy by the converter and
• - a propeller that can be set in rotation by the electric motor.

Further features and advantages of the invention will become apparent from the following explanations of an exemplary embodiment with the aid of schematic drawings.

Figure list

• 1 eine Schnittansicht eines elektrischen Systems gemäß dem Stand der Technik,
• 2 eine Schnittansicht eines elektrischen Systems mit einer verbesserten Kühlung,
• 3 ein Blockschaltbild eines Stromrichters und
• 4 ein Luftfahrzeug mit einem elektrischen System.

Show it:

• 1 a sectional view of an electrical system according to the prior art,
• 2 a sectional view of an electrical system with improved cooling,
• 3 a block diagram of a power converter and
• 4th an aircraft with an electrical system.

Detailed description of the invention

2 Figure 3 shows a sectional view of an electrical system 10 , with a cooling duct open at the top 1.1 a heat sink 1 partly through a power module 2 and in part by driver circuit device 3 is covered. The cover is preferably made cohesively.

A coolant 1.2 in the cooling duct 1.1 flows first at the bottom of the power module 2 and then on the underside of the driver circuit device 3 over to cool these components.

The power module 2 in the cooling duct 1.1 protruding first cooling fins 2.2 on. The line module 2 contains the power semiconductor components not shown in the drawing 2.1 that need to be cooled above all.

The driver circuit device 3 has a ceramic multilayer substrate 3.1 on, in which in the cooling duct 1.1 protruding second cooling fins 3.2 are trained. The multilayer substrate 3.1 forms a cover on part of the cooling duct 1.1 and partially closes it. For electrical connection with the power module 2 are the contact elements 3.3 (only one is shown).

3 shows a block diagram of a power converter 4th , in particular a converter, with an electrical system according to the invention 10 according to the representation of the 2 .

4th shows an electric or hybrid-electric aircraft 6th , in particular an airplane, with a power converter 4th according to 3 having an electric motor 5 supplied with electrical energy. The electric motor 5 drives a propeller 7th on. Both are part of an electrical thrust generation unit. The converter 4th can also be part of an on-board electrical system.

Although the invention has been illustrated and described in more detail by the exemplary embodiments, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.

List of reference symbols

1

Heat sink

1.1

Cooling duct

1.2

Coolant

2

Power module

2.1

Power semiconductor component

2.2

first cooling fin

3

Driver circuit device

3.1

Multilayer substrate

3.2

second cooling fin

3.3

Contact element

4th

Power converter

5

Electric motor

6th

Aircraft

7th

propeller

10

electrical system

Claims (11)

Electrical system (10), comprising: - a heat sink (1) with an open cooling channel (1.1) through which a coolant (1.2) can flow, - a power module (2) that partially covers the cooling channel (1.1) and has power semiconductor components (2.1) ) and - a driver circuit device (3), characterized in that the driver circuit device (3) covers the open remainder of the cooling channel (1.1) in such a way that the driver circuit device (3) can be cooled by the coolant (1.2) flowing past. Electrical system (10) according to Claim 1 , characterized in that the power module (2) has first cooling ribs (2.2) projecting into the cooling channel (1.1). Electrical system (10) according to Claim 1 or 2 , characterized in that the driver circuit device (3) has a ceramic multilayer substrate (3.1), wherein it forms a cohesive cover of the cooling channel (1.1). Electrical system (10) according to Claim 3 , characterized in that the ceramic multilayer substrate (3.1) has second cooling ribs (3.2) projecting into the cooling channel. Electrical system (10) according to one of the preceding claims, characterized in that the coolant (1.2) first flows past the power module (2) and then past the driver circuit device (3), or vice versa. Electrical system (10) according to one of the Claims 3 to 5 , characterized in that the ceramic multilayer substrate (3.1) has a metallization or a metal insert. A method for cooling an electrical system (10), wherein a coolant (1.2) flowing in a cooling channel (1.1) is first applied to a power module (2) of the electrical system (10) having power semiconductor components (2.1) and then to a driver circuit device (3) of the electrical system (10) flows past, or first flows past the driver circuit device and then the power module (2). Converter (4) with an electrical system (10) according to one of the Claims 1 to 6th . Vehicle with a converter (4) after Claim 8 for an electric or hybrid-electric drive. Vehicle after Claim 9 , characterized in that the vehicle is an aircraft (6). Vehicle (6) after Claim 10 , characterized by : - an electric motor (5) supplied with electrical energy by the converter (4) and - a propeller (7) which can be set in rotation by the electric motor (5).

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