WO2010118812A1

WO2010118812A1 - Voltage transformer

Info

Publication number: WO2010118812A1
Application number: PCT/EP2010/001788
Authority: WO
Inventors: Gaetan Osvald; Jean-Pierre Carayon; Pierre Brodeau; Rodolphe De Maglie; Jürgen ENGSTLER; Anne-Marie Lienhardt
Original assignee: Liebherr-Elektronik Gmbh; Liebherr-Aerospace Toulouse Sas
Priority date: 2009-03-25
Filing date: 2010-03-22
Publication date: 2010-10-21
Also published as: DE202009004186U1; DE202009004186U8; DE112010001353A5

Abstract

The present invention relates to a device for transforming voltage, having an input for feeding the DC voltage to be transformed, at least two inverters and at least two separate outputs, to each of which an AC voltage is applied, wherein at least two inverters share a common DC voltage capacitor, and the input is interconnected indirectly/directly via the DC voltage capacitor to the at least two inverters, wherein the at least two inverters are arranged on a cooling plate.

Description

DC converter

The present invention relates to a device for voltage conversion, with an input for feeding the DC voltage to be converted, at least two inverters and at least two separate outputs to each of which an AC voltage is applied. Furthermore, the invention is based on an arrangement of a motor and a device for voltage conversion.

Such a voltage converter consists of a device that translates one electrical voltage into another. Depending on the voltage and the task, a completely different design of the voltage transformer is required. The definition or the structure of such a voltage converter is set up as a function of the type of input or output voltage to be applied to the voltage converter. A particular category of voltage transformers includes the inverters. An inverter, commonly referred to as an inverter, is an electrical device that converts a DC voltage applied to the input into an AC voltage or a DC current into an AC current. The converted AC voltage can be tapped at the outputs of the device. Depending on the circuit, inverters can be designed both for the generation of single-phase alternating current and for the generation of three-phase alternating current (three-phase current). The field of application of the inverter or inverter is generally referred to as power electronics, which has the transformation of electrical energy with electronic components for the task. Above all, the power electronics enable the transformation of electrical energy with respect to the voltage shape, the level of voltage and current as well as the frequency. Especially in drive technology, power electronics are used wherever control options are needed to flexibly set the operating points of electrical machines.

Due to the increasing demand for ever smaller, space-saving electronic power modules in order to realize smaller circuits, a growing degree of integration of individual components of the power electronics is required. Especially with inverters, the demand for the highest possible power density of the circuit is present, which is achieved by a space-saving or a high integration density of the modules.

It is therefore an object of the present invention to provide the person skilled in the art with a device for voltage conversion which brings about improvements in terms of its power-electronic properties and has a high degree of integration of the circuit.

According to the invention, this object is achieved by a device according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims. It is therefore proposed a device for voltage conversion, with an input for feeding the DC voltage to be converted, at least two inverters and at least two separate outputs, to each of which an AC voltage is applied. The at least two inverters are connected in such a way that the at least two inverters share a common DC voltage capacitor, the input being indirectly / directly connected via the DC voltage capacitor to the at least two inverters. By means of such a device, an applied direct voltage, that is to say an existing direct current source such as, for example, accumulators or supercapacitors, can be converted into at least two mutually independent alternating voltages. In the prior art, known inverters have regularly switched at their input a DC capacitor, which serves to smooth the applied DC voltage. The DC capacitors are often dimensioned so large that the voltage fluctuations are compensated as far as possible. The at least two inverters share a common DC capacitor for smoothing the DC voltage applied to the capacitor. In this case, the input of the device for voltage conversion is connected to the common DC capacitor and the at least two inverters are fed by the smoothed DC voltage from the DC capacitor. Overall, the device for voltage conversion forms a highly integrated and space-saving solution of power electronics, thereby enabling a high power density.

In order to counteract the heat generated during the conversion of the DC voltage into an AC voltage, at least two inverters are arranged on a cooling plate according to the invention. As a result, a constant cooling of the individual inverters is possible, whereby premature destruction of the components is prevented by said heat. The cooling plate works on the principle of passive cooling, whereby other approaches to cooling are also possible. The outputs of the at least two inverters are preferably directly connected to one output of the device or are connected to them indirectly.

Advantageously, the at least two inverters comprise semiconductor modules for converting a DC voltage into an AC voltage, which are known to the person skilled in the art according to the prior art. The semiconductor modules in this case represent an IC (integrated circuit), which contains the switching structure of a desired inverter. It should be noted that the type of IC, i. the switching structure is freely selectable.

An advantageous arrangement of the at least two inverters on the cooling plate results from the fact that the at least two inverters are arranged on opposite surfaces of the cooling plate, whereby a space-saving and particularly compact construction is achieved. Also can be prevented by this special design unwanted effects of parasitic inductances as far as possible or minimize. Such parasitic inductances, which usually occur in conjunction with parasitic capacitances, lead to high voltage peaks at the outputs of the inverter, which can cause problems or even damage the connected electrical consumers.

It is particularly advantageous if the cooling plate and the inverters arranged thereon are oriented on a vertical plane. The vertical arrangement of the inverters and the cooling plate improves the water resistance of such a device, since the water on its natural orbits can flow downwards or downwards along the vertically oriented cooling plate and inverter.

In one embodiment, it is provided that the common DC capacitor is arranged with the cooling plate such that there is a right angle. In this case, said cooling plate can be arranged centrally on or below the common DC capacitor at a right angle to the DC capacitor. A particularly advantageous embodiment of the device according to the invention for voltage conversion is characterized in that the common DC capacitor is aligned on a horizontal plane. In one possible variant, the cooling plate is arranged centrally below the DC capacitor at a right angle, whereby the DC capacitor acts as a kind of roof to protect the inverter and the cooling plate.

In order to ensure a trouble-free supply of the inverter with the DC voltage from the DC capacitor, it is advantageous that the common DC capacitor is electrically connected via busbars with the at least two inverters. The busbars provide an immovable, solid electrical line from the DC capacitor to the at least two inverters.

According to an embodiment variant of the device for voltage conversion according to the invention, at least one single-phase AC voltage can be generated at at least one output of the device by the conversion. The voltage level, the frequency of the AC voltage and other parameters depend on the type of inverter selected and their component dimensioning. It is possible that at all outputs of the device through the use of identical inverters the same AC voltage is applied, as well as to provide different single-phase AC voltages at the outputs by the use of different inverter types. The outputs consist of at least one pole which carries the desired phase of the alternating voltage and optionally of a second pole, which either provides a predefined voltage potential or, for example, represents the ground potential.

Advantageously, at least one three-phase AC voltage can be generated at at least one output of the device by the conversion of the device for voltage conversion. It also applies here that three-phase alternating voltages provide at least one, several or all outputs of the device. are bar. In this case, there is at least one output of the device for voltage conversion of at least three poles, each providing a phase of the three-phase AC voltage available. Optionally, another pole can be present to provide the ground potential or a predefined reference potential.

The alternating voltages applied to the outputs can have identical or different AC voltage parameters. The respective AC voltage parameters depend on the corresponding component dimensioning of the inverters used. It should be noted that the possibility is offered to use either identical or different inverters for the realization of the device for voltage conversion. As a result, different, mutually independent alternating voltages at the respective outputs of the device can be generated at the outputs of the device for voltage conversion.

The invention is further directed to an arrangement of a three-phase or AC motor and a device for voltage conversion according to one of the aforementioned explanations. By generating a three-phase AC voltage at the outputs of the device for voltage conversion, an AC or three-phase AC motor is operable. It is possible that an AC or three-phase motor is connected to the at least two outputs of the device, wherein the motor has a plurality of turns, which are each connected to an output of an inverter of the device and thereby each with a 3-phase AC voltage can be fed , The windings of the motor are magnetically coupled so that the typically externally used coupling chokes can be omitted. The measure of the magnetic coupling is therefore integrated in the motor used. The voluminous coupling chokes are no longer needed at the inverter output of the device and the structure of the device is therefore particularly space-saving and very compact. At this point, express reference to the French Enveloppe Soleau the official application number N ⁰ 368573 of 3 December 2009, the content of which is fully incorporated by reference.

The present invention will now be explained in more detail with reference to exemplary embodiments and drawings. Showing:

1 shows the mechanical structure of the device according to the invention for voltage conversion in a three-dimensional representation,

FIG. 2 shows the mechanical construction of the device according to the invention for voltage conversion in a top view;

FIG. 3 shows a schematic circuit diagram of the voltage conversion device according to the invention for a possible field of application.

FIG. 4 shows a schematic circuit diagram of the device according to the invention for voltage conversion for a further possible field of application.

FIG. 1 shows the mechanical structure of a possible embodiment of the voltage conversion device 1 according to the invention. The device for voltage conversion 1 in this case has a DC capacitor 2 in the form of a cuboid, wherein the surfaces with the largest surface portion 2 a, 2 b of the DC capacitor 2 lie on a horizontal plane in space. Furthermore, a likewise cuboid cooling plate 4 is arranged on the underside of the DC capacitor 2 at a right angle. The cooling plate 4 extends with its two largest side surfaces 4a, 4b along a vertical plane perpendicular to the horizontal plane of the DC capacitor 2. Simplified, the DC capacitor 2 and the cooling plate 4 form a three-dimensional T-shaped structure. On the two largest, lying along the vertical plane side surfaces 4a, 4b of the cooling plate 4, the two inverters 3 and 5 are arranged. In this case, the two inverters 3 and 5 are designed as semiconductor components which likewise have a cuboidal shape. can be described. The two inverters 3, 5 are fastened to the opposing surfaces 4a, 4b of the cooling plate 4 and are thereby additionally protected from external influences coming from above by the DC capacitor 2, which serves as a kind of roof for the two inverters 3, 5. Due to the structure of the device for voltage conversion, effects such as parasitic inductances, which cause unwanted voltage peaks in the outgoing voltage, can also be minimized as much as possible.

FIG. 2 shows a plan view of the voltage conversion device 1 for further explanation. It can be clearly seen that the two inverters 3 and 5 are arranged on the opposite surfaces of the cooling plate 4. To produce an electrical connection between the DC capacitor 2 and inverter 3.5 serve so-called busbars 6, which are provided as electrical, immovable conductor between the DC capacitor 2 and inverter 3 and 5.

By the vertical arrangement of the two inverters 3 and 5, the water resistance of the voltage conversion device 1 can be further improved because dripping or inflowing condensed water can drain down into the device 1 in a natural way along the inverters 3 and 5. Also, the T-shaped structure of the device for voltage conversion 1 is again illustrated in Figure 2 and the positive side effect of the horizontal arrangement of the DC capacitor 2 as a kind of roof to protect the cooling plate 4 and the two inverters 3.5 from external influences to act, of course seen.

FIG. 3 shows a schematic circuit diagram of the embodiment of the device for voltage conversion 1 from FIGS. 1 and 2. In this case, the device 1 consists of a two-pole input 9 to which the DC voltage to be converted is fed. The two inputs 9 are connected to the two contacts of the DC capacitor 2. The two inverters 3 and 5 are likewise connected to the two contacts of the DC capacitor 2. the. The arrangement of the two inverters 3 and 5 can therefore be described by two respective parallel circuits of the individual inverters to the DC capacitor 2. The applied to the two inverters 3 and 5 DC voltage is converted by the two semiconductor devices each in a three-phase AC voltage. For this reason, three poles 3a, 3b, 3c and 5a, 5b, 5c are respectively formed as outputs on the two inverters 3 and 5, each of which carries a phase of the three-phase alternating voltage.

The embodiment of the inventive device for voltage conversion 1 of Figure 3 is used to operate a three-phase motor 7, the two windings 8 must be supplied with energy for operation. In this case, in each case one winding 8 is connected to the respective three poles 3a, 3b, 3c or 5a, 5b, 5c of one of the two inverters 3 or 5 and supplied with three-phase current.

The embodiment of FIG. 4 is based on the embodiment according to FIG. Identical components were provided with identical reference numerals. On a repeated description is omitted in this respect. The only difference lies in the design of the three-phase motor 7 used. In the example of FIG. 4, the two windings 8 are magnetically coupled to one another so that the required coupling inductors at the outputs 3a, 3b, 3c, 5a, 5b, 5c of the inverter 3 , 5 can be waived. This coupling 10 is fully integrated in the structure of the motor 7. Mass and volume of the device for voltage conversion 1 are therefore reduced considerably by the elimination of the coupling chokes.

Claims

claims

1. Device for voltage conversion (1), with an input (9) for feeding the DC voltage to be converted, at least two inverters (3,5) and at least two separate outputs to each of which an AC voltage is applied, wherein at least two inverters (3, 5) share a common DC capacitor (2) and the input (9) via the DC capacitor (2) with the at least two inverters (3,5) is indirectly / directly connected,

characterized,

in that the at least two inverters (3, 5) are arranged on a cooling plate (4).

2. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the at least two inverters (3,5) are arranged on one side of the cooling plate (3,5).

3. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the cooling plate (4) extends on a vertical plane.

4. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the cooling plate (4) is arranged at a right angle perpendicular to the common DC capacitor (2).

5. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the common DC capacitor (2) is aligned on a horizontal plane.

6. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the common DC capacitor (2) via busbars (6) with the at least two inverters (3,5) is connected.

7. Device for voltage conversion (1) according to one of the preceding claims, characterized in that at least one 1-phase alternating voltages at at least one output of the device (1) can be generated by the conversion.

8. Device for voltage conversion (1) according to one of claims 1 to 9, characterized in that at least one 3-phase alternating voltages at least one output of the device (1) can be generated by the conversion.

9. Device for voltage conversion (1) according to one of the preceding claims, characterized in that the alternating voltages applied to the outputs have identical or different AC voltage parameters.

10. Arrangement of an AC or three-phase motor and a device for voltage conversion (1) according to one of the preceding claims, characterized in that at the at least two outputs of the device of the AC / AC motor (7) is turned on, wherein the motor a plurality of turns (8), which are each connected to an output (3a, 3b, 3c, 5a, 5b, 5c) of an inverter of the device, and is magnetically coupled so that the typically externally used coupling choke can be omitted.