MINIMALISTIC POWER CONVERTER AND VEHICLE INCLUDING A POWER CONVERTER

Abstract

A power Converter having power semiconductor components is disclosed herein, wherein a DC-link capacitor has a capacitance of less than 3 μF and is not designed as a separate electrical device of the power converter, and wherein the clock frequency is greater than 1 MHz. A vehicle, (e.g., an aircraft), including a power Converter of this kind is also described.

Claims

1. A power converter comprising: power semiconductor devices, wherein a DC-link capacitor has a capacitance of less than 3 μF and is not in a form of a separate electrical device of the power converter, and wherein a clock frequency for switching the power semiconductor devices is greater than 1 MHz.

2. The power converter of claim 1, further comprising: a first supply line and a second supply line as electrical connections to a DC voltage source, wherein the first and second supply lines are implemented immediately before the power semiconductor devices in a widened and planar form such that a plate capacitor is configured to be formed as the DC-link capacitor.

3. The power converter of claim 2, further comprising: a plastic-film as a dielectric of the plate capacitor.

4. The power converter of claim 3, wherein the power converter is an inverter.

5. The power converter of claim 4, further comprising: three AC terminals; and a heat sink, wherein the power semiconductor devices comprise six power semiconductor devices in Gallium Nitride (GaN) technology having monolithically integrated driver circuits and protection functions and having galvanically isolated communication interfaces.

6. The power converter of claim 5, wherein the first and second supply lines each have a planar design, and wherein three power semiconductor devices of the six power semiconductor devices are arranged on a top face of the first supply line and a top face of the second supply line.

7. The power converter of claim 5, wherein the first and second supply lines each have an L-shaped design, and wherein three power semiconductor devices of the six power semiconductor devices are arranged on a top face of a shorter leg of the first supply line and a top face of a shorter leg of the second supply line.

8. A vehicle comprising: a power converter for an electric or hybrid electric drive, wherein the power converter comprises: power semiconductor devices, wherein a DC-link capacitor has a capacitance of less than 3 μF and is not in a form of a separate electrical device of the power converter, and wherein a clock frequency for switching the power semiconductor devices is greater than 1 MHz.

9. The vehicle of claim 8, wherein the vehicle is an aircraft.

10. The vehicle of claim 9, wherein the aircraft is an airplane.

11. The vehicle of claim 10, further comprising: an electric motor configured to be supplied with electrical energy by the power converter, and a propeller configured to be set in rotation by the electric motor.

12. The vehicle of claim 8, wherein the power converter further comprises a first supply line and a second supply line as electrical connections to a DC voltage source, and wherein the first and second supply lines are implemented immediately before the power semiconductor devices in a widened and planar form such that a plate capacitor is configured to be formed as the DC-link capacitor.

13. The vehicle of claim 12, wherein the power converter further comprises a plastic-film as a dielectric of the plate capacitor.

14. The vehicle of claim 13, wherein the power converter is an inverter.

15. The vehicle of claim 14, wherein the power converter further comprises three AC terminals and a heat sink, and wherein the power semiconductor devices comprise six power semiconductor devices in Gallium Nitride (GaN) technology having monolithically integrated driver circuits and protection functions and having galvanically isolated communication interfaces.

16. The vehicle of claim 15, wherein the first and second supply lines each have a planar design, and wherein three power semiconductor devices of the six power semiconductor devices are arranged on a top face of the first supply line and a top face of the second supply line.

17. The vehicle of claim 15, wherein the first and second supply lines each have an L-shaped design, and wherein three power semiconductor devices of the six power semiconductor devices are arranged on a top face of a shorter leg of the first supply line and a top face of a shorter leg of the second supply line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a block diagram of a power converter according to the prior art.

[0033] FIG. 2 is a block diagram of an example of a power converter without a DC-link capacitor.

[0034] FIG. 3 is a side view of an example of first and second supply lines of a power converter.

[0035] FIG. 4 is an oblique view of an example of first and second supply lines of a power converter.

[0036] FIG. 5 is a side view of a first embodiment of a minimalist power converter.

[0037] FIG. 6 is a side view of a second embodiment of a minimalist power converter.

[0038] FIG. 7 shows an example of an aircraft including an electric thrust generating unit.

DETAILED DESCRIPTION

[0039] FIG. 1 shows a block diagram of a power converter 1 according to the prior art. The commutation cell 1.1 of one phase may be seen. A DC-link capacitor 2 is connected on the input side to a battery 8 or another DC voltage source. The DC-link capacitor 2 is connected on the output side to the power module 5, which contains the switchable power semiconductor devices 5.1 (not shown). A heatsink 7 removes heat from both the DC-link capacitor 2 and the power module 5. For higher levels of power dissipation, the heatsinks 7 are liquid cooled.

[0040] FIG. 2 shows a block diagram of a power converter 1 without a DC-link capacitor 2 as a standalone, separate device. The commutation cell 1.1 of one phase may be seen. There is no standalone DC-link capacitor 2 present. The power module 5 is connected directly to a battery 8 or another DC current source via the first supply line 3.1 (DC+) and the second supply line 3.2 (DC−). The power module 5 contains the switchable power semiconductor devices 5.1 (not shown). The first and second supply lines 3.1, 3.2 form a DC-link capacitor 2 in the form of a plate capacitor. A heatsink 7 removes heat from the power module 5 and the plate capacitor. For higher levels of power dissipation, the heatsink 7 is liquid cooled.

[0041] The DC-link capacitor 2 has a capacitance of 2 μF. The power module 5 switches at a clock frequency of 1 MHz.

[0042] FIG. 3 shows a side view of the power converter 1 according to FIG. 2. The first and second supply lines 3.1, 3.2 are in part in the form of a plate capacitor, thereby forming the DC-link capacitor 2. The first and second supply lines 3.1, 3.2 are electrically connected to the power module 5. A plastic-film 4 having a high electric dielectric strength and for the purpose of increasing the capacitance of the DC-link capacitor 2 lies between the supply lines 3.1, 3.2, which are arranged parallel to one another.

[0043] FIG. 4 shows an oblique view of the first and second supply lines 3.1, 3.2 of the power converter 1 according to FIG. 3. The first and second supply lines 3.1, 3.2 are broadened in part in order to form a sufficiently large area for the plate capacitor.

[0044] FIG. 5 shows a side view of a first embodiment of a minimalistic power converter 1 according to FIG. 2 to FIG. 4. On the first and second copper supply lines 3.1, 3.2 are sintered six power semiconductor devices 5.1, three on each supply line 3.1, 3.2 (also called a “busbar”). Only two may be seen. A polypropylene plastic-film 4 lies between the supply lines 3.1, 3.2.

[0045] On the plate-shaped supply lines 3.1, 3.2 sits a heatsink 7 in a sandwich construction. The generated AC current may be fed to a load via the three AC terminals 6. Only one may be seen. The power semiconductor devices 5.1 may be configured in GaN technology. The power semiconductor devices 5.1 in particular are field effect transistors.

[0046] FIG. 6 shows a side view of a second embodiment of a minimalist power converter 1 according to FIG. 2 to FIG. 4. The first and second supply lines 3.1, 3.2 are L-shaped, each having a long leg and a short leg. On the short legs of the first and second copper supply lines 3.1, 3.2 are sintered six power semiconductor devices 5.1, three on each supply line 3.1, 3.2. Only two may be seen. A polypropylene plastic-film 4 lies between the supply lines 3.1, 3.2.

[0047] On the long legs of the plate-shaped supply lines 3.1, 3.2 sits a heatsink 7 in a sandwich construction. The generated AC current may be fed to a load via the three AC terminals 6. Only one may be seen. The power semiconductor devices 5.1 may be configured in GaN technology. The power semiconductor devices 5.1 may be MOSFETs, IGBTs, or IGCTs.

[0048] The DC-link capacitor 2 may be considered to be a direct supply line 3.1, 3.2 from the energy source, which supply line has a modified form factor. A plate capacitor may be realized. If the capacitance needs to be increased, a small number of parallel-connected windings may be mounted geometrically one above the other. If a winding number of 1, (an ideal plate capacitor), is selected, then the DC-link capacitor in the form of an explicit component disappears from the extremely fast-switching inverter, because is it then a “parasitic” element of the widened first and second supply lines 3.1, 3.2. The DC-link inductance falls to a minimum.

[0049] FIG. 7 shows an electric or hybrid-electric airplane 9 as an example of an aircraft, including a power converter 1 according to FIG. 2 to FIG. 6, which supplies an electric motor 9.1 with electrical energy. The electric motor 9.1 drives a propeller 9.2. Both are part of an electrical thrust generating unit. The power converter 1 may also be used for other applications, for instance an on-board electrical system or a battery supply.

[0050] Although the disclosure has been described and illustrated more specifically in detail by the exemplary embodiments, the disclosure is not restricted by the disclosed examples and other variations may be derived therefrom by a person skilled in the art without departing from the scope of protection of the disclosure.

[0051] It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present disclosure. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.

LIST OF REFERENCE SIGNS

[0052] 1 Power converter [0053] 1.1 Commutation cell [0054] 2 Intermediate circuit capacitor [0055] 3.1 First supply line [0056] 3.2 Second supply line [0057] 4 Plastic-film [0058] 5 Power module [0059] 5.1 Power semiconductor device [0060] 6 AC terminal [0061] 7 Heatsink [0062] 8 Battery [0063] 9 Airplane [0064] 9.1 Electric motor [0065] 9.2 Propeller