Electrical power transfer device comprising a multi-source dc / dc converter

Abstract

The invention relates to an electrical power transfer device comprising a DC / DC converter (2), a rectifier (3), a first inverter (4) and a second inverter (5). The DC / DC converter (2) comprises: - a transformer (20) comprising n primary windings and a secondary winding, n being a natural number at least equal to two; - a first switching assembly comprising n active bridges electrically separated from one another, each active bridge being configured to be connected, on the one hand, to a DC power source (S1, S2) and being connected, on the other hand, to one of the primary windings; and - a second switching assembly connected, on the one hand, to the secondary winding and, on the other hand, to the first inverter (4) and to the second inverter (5).

Description

DESCRIPTION Title of the invention: Electrical power transfer device comprising a multi-source DC / DC converter.

[0001] The invention relates to an electrical power transfer device. The invention applies to any type of device for transferring electrical power. It is particularly applicable to aeronautical devices.

[0002] In various fields, particularly aeronautics, there is an increasing need for electricity to power electronic devices. We are therefore seeing an increase in on-board electrical energy. At the same time, there is a significant constraint in reducing weight and / or volume.

[0003] Figure 1 shows in particular an example of a prior art power transfer device. This is a starting power converter used in aeronautics and also called SBU (for “smart box unit” in English). The SBU ensures the starting of a main network or an auxiliary power unit or APU (for “Auxiliary Power Unit” in English) by means of a 115V network or a 0-28V battery.

[0004] The SBU has the disadvantage of being a dead mass carried only for a ground start function.

[0005] The invention aims to provide an electrical power transfer device capable of meeting both electrical needs and weight / volume constraints.

[0006] The invention proposes for this purpose an electrical power transfer device comprising: - a direct current / direct current converter, called a DC / DC converter; - a rectifier configured to be connected to an alternating voltage source; - a first inverter connected on the one hand to the DC / DC converter and to the rectifier, the first inverter being configured to supply on the other hand a main network of an electrical machine; and a second inverter connected on the one hand to the rectifier and to the DC / DC converter, the second inverter being configured to supply on the other hand an exciter of the electrical machine.

[0007] According to the invention, the DC / DC converter comprises: - a transformer comprising n primary windings and one secondary winding, n being a natural integer at least equal to two; - a first switching assembly comprising n active bridges electrically separated from each other, each active bridge being configured to be connected on the one hand to a DC power source and being connected on the other hand to one of the primary windings; and - a second switching assembly connected on the one hand to the secondary winding and on the other hand to the first inverter and to the second inverter.

[0008] The transfer device allows for multiple power transfer paths by multiplying the sources. Indeed, thanks to the DC / DC converter and the rectifier, several power source connections are possible: the AC voltage source or the n DC voltage sources. This allows for the creation of different energy flows depending on the needs. It is thus possible to ensure several functions related to the generation and distribution of energy but also battery recharging.

[0009] Furthermore, the invention makes it possible to reduce the weight and volume of the transfer device since the DC / DC converter combines several functions.

[0010] Finally, by disconnecting the active bridges of the first switching set from each other, this makes each active bridge independent. Power can thus be transferred independently between each primary winding and the secondary winding.

[0011] Particularly convenient preferred features of the transfer device according to the invention are presented below.

[0012] The DC / DC converter is reversible.

[0013] The DC / DC converter and the rectifier are configured to deliver the same output voltage.

[0014] The output voltage is 270V.

[0015] The DC power source is a battery, preferably a 0-28V battery or a 0-400V battery.

[0016] The AC voltage source is a ground-mounted power supply, preferably a ground-mounted power supply providing 115V.

[0017] The transfer device is a power converter at startup.

[0018] The transformer is an electrical isolation transformer.

[0019] The first inverter is three-phase type and the second inverter is single-phase type.

[0020] Other features and advantages of the invention will become apparent in the description below with reference to the appended drawings, given as non-limiting examples: - Figure 1 represents a power converter at start-up of the prior art; - Figure 2 schematically represents a power transfer device according to one embodiment of the invention; and - figure 3 represents an exemplary embodiment of a DC / DC converter of the transfer device of figure 2.

[0021] Figure 2 represents an exemplary embodiment of a power transfer device 1 according to the invention. The power transfer device is in this example an SBU (for “smart box unit” in English) or power converter at start-up.

[0022] The SBU is traditionally used to control and power a starter-generator during the start-up of aeronautical vehicles. The starter-generator, also known by the abbreviation S / G for its English acronym "Starter-Generator", is used as a starter for starting, for example, turbojets, turboprops, turboshafts for aeronautical use and as the main generator for the on-board electrical network of airplanes, helicopters and drones. The starter-generator is an electrical machine that operates in starter mode to start an engine, then in generator mode to provide the electrical power required for an on-board network or any other system requiring electrical power.

[0023] The transfer device 1 comprises a direct current / direct current converter 2, a rectifier 3, a first inverter 4 and a second inverter 5.

[0024] The DC / DC converter 2, hereinafter referred to as the DC / DC converter, is configured to be connected to multiple DC power sources S1, S2. The DC / DC converter 2 is thus multi-source.

[0025] Preferably, the continuous power sources are batteries.

[0026] In the example shown, the DC / DC converter 2 is configured to be connected to two DC power sources S1, S2, called first DC power source S1 and second DC power source S2. The first DC power source S1 is a 0-28V battery. The second DC power source S2 is a 0-400V battery.

[0027] The DC / DC converter 2 is connected on the other hand, in particular at the output, to the first inverter 4 and to the second inverter 5. The DC / DC converter 2 is configured to deliver an output voltage to the first inverter 4 and the second inverter 5. The output voltage here is 270V.

[0028] An example of the topology of the DC / DC converter 2 is shown in Figure 3. The DC / DC converter 2 comprises a transformer 20, a first switching assembly 21 and a second switching assembly 22.

[0029] The transformer 20 comprises n primary windings W1a, W1b and one secondary winding W2, n being a natural integer at least equal to two. In the example shown, the transformer 20 comprises two primary windings hereinafter called first primary winding W1a and second primary winding W1b.

[0030] The primary windings W1 a, W1 b are connected to the first switching assembly 21. The secondary winding W2 is connected to the second switching assembly 22.

[0031] Transformer 20 is here an electrical isolation transformer. Such a transformer provides galvanic isolation between the primary current and the secondary current. The primary windings W1 a, W1 b and the secondary winding W2 are electrically separated by main insulation. This ensures isolation in the event of problems that may arise in the various DC power sources. The electrical isolation transformer therefore constitutes a safety device.

[0032] The first switching assembly 21 comprises n active bridges 210a, 210b. Each active bridge 210a, 210b is configured to be connected, in particular at the input, to one of the DC power sources S1, S2. Each active bridge 210a, 210b is connected, in particular at the output, to one of the primary windings W1a, W1b of the transformer 20.

[0033] The active bridges 210a, 210b of the first switching assembly 21 are electrically disconnected from each other. This makes them independent of each other and allows, as explained below, power transfers in a completely independent manner.

[0034] The first switching assembly 21 here comprises two active bridges 210a, 210b, called first active bridge 210a and second active bridge 210b. The first active bridge 210a is configured to be connected, in particular at the input, to the first DC power source S1 (here to the 0-28V battery). The first active bridge 210a is connected, in particular at the output, to the first primary winding W1a of the transformer 20. The second active bridge 210b is configured to be connected, in particular at the input, to the second DC power source S2 (here to the 0-400V battery). The second active bridge 210b is connected, in particular at the output, to the second primary winding W1b of the transformer 20.

[0035] The first active bridge 210a is electrically disconnected from the second active bridge 210b.

[0036] The second switching assembly 22 comprises the output terminals through which the output voltage of the DC / DC converter 2 is delivered, here a voltage of 270V.

[0037] The second switching assembly 22 comprises an active bridge 220. The active bridge 220 outputs the output voltage, here 270V. The active bridge 220 is connected via the output terminals to the first inverter 4 and to the second inverter 5.

[0038] The active bridge 220 of the second switching assembly 22 is connected on the other hand to the secondary winding W2.

[0039] The DC / DC converter 2 described above is thus of the active bridge type. The DC / DC converter 2 according to the invention differs in particular from the active bridge type converters of the prior art in that the ports of the active bridges are separate (i.e. not connected).

[0040] The DC / DC converter 2 is advantageously reversible.

[0041] The rectifier 3 is configured to be connected to an AC voltage source S3. The AC voltage source S3 may be a ground power unit (GPU). The GPU corresponds to a source to which the aircraft systems can be connected when the aircraft is parked on the ground via a ground socket and which produces an AC voltage called ground voltage. For example, the ground power unit provides an AC voltage of 115V.

[0042] Rectifier 3 converts AC voltage to DC voltage. It is an active rectifier sized based on the highest DC output voltage and the lowest AC input voltage.

[0043] The output voltage of rectifier 3 is the same as the output voltage of DC / DC converter 2, here 270V.

[0044] The first inverter 4 is connected to the DC / DC converter 2. The first inverter 4 is in particular connected to the second switching assembly 22, more particularly to the active bridge 220 of the second switching assembly 22. The first inverter 4 is configured to be connected on the other hand to a main network (or "Main" in English) of an electrical machine, typically the main network of the generator / starter. The first inverter 4 thus makes it possible to supply the main network.

[0045] The first inverter 4 is advantageously of the three-phase type.

[0046] The second inverter 5 is connected to the DC / DC converter 2. The second inverter 5 is in particular connected to the second switching assembly 22, more particularly to the active bridge 220 of the second switching assembly 22. The second inverter 5 is configured to be connected to other part to an exciter of the electrical machine, typically the exciter of the generator / starter. The second inverter 5 thus makes it possible to supply the exciter.

[0047] The second inverter 5 is advantageously of the single-phase type.

[0048] Figure 3 represents by arrows the power transfers permitted by the DC / DC converter 2 of the invention. The reversibility of the DC / DC converter 2 allows the reversibility of the power transfers.

[0049] The arrow F1 represents the possibility of transferring power from the first continuous power source S1, here the 28V battery, to the second switching assembly 22. This transfer notably enables the starting function provided by the 28V battery. This is a function used mainly in flight in the case of the SBU in the absence of the GPU ground battery. Indeed, when starting the aircraft, if the start takes place on the ground then the GPU ground battery can be used. If the start is carried out in flight then the 28V battery can be used as an alternative to the GPU ground battery.

[0050] Arrow F2 represents the possibility of power transfer opposite to that of arrow F1. Arrow F2 represents the possibility of power transfer from the second switching assembly 22 to the first continuous power source S1, here the 28V battery. In other words, it is possible to recharge the 28V battery from the second switching assembly 22.

[0051] Arrow F3 represents the possibility of transferring power from the second continuous power source S2, here the 400V battery, to the second switching assembly 22. Like the transfer represented by arrow F1, this transfer notably allows the starting function provided by the 400V battery. This is a function used mainly in flight in the case of the SBU in the absence of the GPU ground fleet.

[0052] Arrow F4 represents the possibility of power transfer opposite to that of arrow F3. Arrow F4 represents the possibility of power transfer from the second switching assembly 22 to the second DC power source S2, here the 400V battery. In other words, it is possible to recharge the 400V battery from the second switching assembly 22.

[0053] Arrow F5 represents the possibility of power transfer from the second DC power source S2 to the first power source continues S1. In other words, it is possible to recharge the 28V battery using the 400V battery.

[0054] In the case of the SBU start-up power converter, the arrows F2 and F4 make it possible to take advantage of an inertia created by an aircraft engine in flight. Indeed, the engine can return energy from the main network to the second switching assembly 22. Thanks to the configuration of the DC / DC converter according to the invention, this energy is used to recharge the 28V battery or the 400V battery.

[0055] The transfer device according to the invention allows, thanks to the multi-source connection DC / DC converter, to have several electrical inputs and outputs and to create different power flows according to needs. These power flows are independent thanks to the separation of the active bridges.

[0056] The structure of the transfer device allows several functions to be shared in the same device thanks to the DC / DC converter.

[0057] The invention allows the use of a single DC / DC converter but also a single rectifier, thus avoiding duplicating energy transfer chains and thus reducing the volume and weight of the transfer device.

[0058] The invention is not limited to the start-up power converter (SBU) described here as an example. Indeed, the invention applies to any type of device having the function of generating, transferring and / or distributing electrical power. The invention can be used for this purpose with any type of electrical machine.

Claims

CLAIMS 1. Electrical power transfer device comprising: - a direct current / direct current converter (2), called a DC / DC converter; - a rectifier (3) configured to be connected to an alternating voltage source (S3); - a first inverter (4) connected on the one hand to the DC / DC converter (2) and to the rectifier (3), the first inverter (4) being configured to supply on the other hand a main network of an electrical machine; and - a second inverter (5) connected on the one hand to the rectifier (3) and to the DC / DC converter (2), the second inverter (5) being configured to supply on the other hand an exciter of the electrical machine, the transfer device (1) being characterized in that the DC / DC converter (2) comprises: - a transformer (20) comprising n primary windings (W1a, W1b) and one secondary winding (W2), n being a natural integer at least equal to two; - a first switching assembly (21) comprising n active bridges (210a, 210b) electrically separated from each other, each active bridge (210a, 210b) being configured to be connected on the one hand to a DC power source (S1, S2) and being connected on the other hand to one of the primary windings (W1a, W1b); and - a second switching assembly (22) connected on the one hand to the secondary winding (W2) and on the other hand to the first inverter (4) and to the second inverter (5).

2. Transfer device according to claim 1, in which the DC / DC converter (2) is reversible.

3. Transfer device according to claim 1 or claim 2, in which the DC / DC converter (2) and the rectifier (3) are configured to deliver the same output voltage.

4. Transfer device according to claim 3, wherein the output voltage is 270V.

5. Transfer device according to one of claims 1 to 4, wherein the continuous power source (S1, S2) is a battery, preferably a 0-28V battery or a 0-400V battery.

6. Transfer device according to one of claims 1 to 5, in which the alternating voltage source (S3) is a ground-based park group, preferably a ground-based park group providing a voltage of 115V.

7. Transfer device according to one of claims 1 to 6, said transfer device (1) is a power converter at start-up.

8. Transfer device according to one of claims 1 to 7, in which the transformer (20) is an electrical isolation transformer.

9. Transfer device according to one of claims 1 to 8, in which the first inverter (4) is of the three-phase type and the second inverter (5) is of the single-phase type.

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