Alternator with voltage doubler circuit

Abstract

A power supply system configured to electrically supply a load, comprising an electric generator (4) including a rotor (6) and a stator (8) including three windings (10a, 10b, 10c) each including a first end (P1, P2, P3) and a second end (N1, N2, N3), the power supply system including a matching circuit (1) in parallel with a load (2) and including three rectifier circuits (30a, 30b, 30c) in series, each including in parallel a first branch (31a, 31b, 31c) coupled to a first end (P1, P2, P3) and a second branch (32a, 32b, 32c) coupled to a second end (N1, N2, N3), the matching circuit (1) being configured to switch from a first operating mode in which only the first branch (31a, 31b, 31c) is to a second operating mode in which the first branch (31a, 31b, 31c) and the second branch (32a, 32b, 32c) are conducting. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Alternator with voltage doubling circuit

[0001] DOMAIN

[0002] The present invention relates to the field of electric generators and power conversion circuits, and more specifically to an electric generator equipped with a circuit for selecting between a nominal rectified voltage or a voltage twice the nominal rectified voltage as the output voltage. Such a device can find particular application in aeronautics, for turboshaft engines having an electric generator driven by a drive shaft, prior art

[0003] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those currently in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively contributing to the fight against climate change for several years now.

[0004] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental impacts, with the aim of improving the energy efficiency of these aircraft.

[0005] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] This sustained research and development work focuses on new generations of aircraft turbomachinery, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0007] Certain components of an aircraft require a continuous power supply to ensure the continuity of essential services. This electricity may be Power is generated by an electric generator, or alternator, driven by a turbomachine's drive shaft. The drive shaft is connected, for example, to a low-pressure turbine, a high-pressure turbine, or any other component that rotates during the turbomachine's operation. However, combustion in the turbomachine can sometimes stop in flight, in which case the electric generator is no longer driven by the turbomachine's fuel combustion.

[0008] Even in the event of the turbomachine stopping, it is necessary that the electric generator continue to produce electricity to at least supply essential services of the turbomachine, such as supplying the full-authority digital engine control system, better known by the acronym FADEC for "full-authority digital engine control", or to provide electrical power to a possible motor pump for fuel metering.

[0009] In the event of a stoppage of the operation of the turbomachine, the electric generator is driven only by the action of the dynamic pressure of the forward movement of the aircraft acting on the elements of the turbomachine, an operation known as autorotation or "windmilling" in English.

[0010] The dynamic pressure that drives the drive shafts into autorotation is limited by the following phenomena: - At high altitudes, the available dynamic pressure is lower as the air density decreases. - at restart altitude (~25,000 feet), the aircraft's Mach number is lower, also limiting the dynamic pressure, - the shaft driving the generator generally drives other equipment (aircraft pumps, lubrication, etc.), which induces torque withdrawals further reducing this autorotation regime.

[0011] Since the rectified voltage obtained from the electric generator depends on the rotational speed of the drive shaft, this voltage may become too low to power certain electronic components. The electric generator may then be unable to supply essential services to the turbomachine.

[0012] Patent application FR3050083 mentions that it is known in the prior art of power conversion circuits comprising an inverter coupled downstream of a DC / DC converter with synchronous rectification, which is also called in English PAM for "Power Amplitude Modulation", which can be of the voltage step-down (or "buck" in English), voltage step-up (or "boost" in English) or voltage step-up (or "buck-boost" in English) type.

[0013] However, such voltage step-up circuits generally use components such as transformers, inductors and capacitors, and ne require high-frequency and high-power switches. These requirements can result in complex, bulky, and expensive circuits.

[0014] Consequently, the electric generator is generally oversized to be able to supply sufficient voltage during autorotation, and more specifically at the restart altitude. As a result, the electric generator is generally heavy, bulky, and supplies too high a voltage in normal operating mode, necessitating additional electronic components. PRESENTATION OF THE INVENTION

[0015] The present invention aims to enable obtaining from a generator a sufficient supply voltage even when the motor shaft driving the generator rotates at low speed, limiting the oversizing of the electric generator, particularly in the case of autorotating operation of an aircraft turbomachine, in a compact, simple and economical manner.

[0016] In this regard, a power supply system is proposed, configured to electrically supply a load comprising a three-phase electric generator configured to be driven in rotation by a motor shaft, the electric generator comprising a rotor and a stator, the stator comprising three windings each corresponding to one phase of the electric generator, each winding comprising a first end and a second end opposite to the first end,

[0017] in which the power supply system includes an adaptation circuit configured to be connected in parallel to the load and comprising three rectifier circuits coupled in series, each rectifier circuit comprising a first branch and a second branch in parallel with the first branch, the first branch being coupled to the first end of a respective winding, and the second branch being coupled to the second end of said winding,

[0018] the adaptation circuit being configured to switch from a first operating mode in which only the first branch is conducting and where a nominal value output voltage is supplied to the load, to a second operating mode in which the first branch and the second branch are conducting and where an output voltage of double the nominal value is supplied to the load.

[0019] The invention makes it possible to adapt the rectified supply voltage obtained from a three-phase generator to ensure sufficient voltage is supplied even when the generator's rotational speed decreases, while limiting the supply voltage when the generator is driven at a higher speed, without requiring complex, expensive, or bulky components. This allows the use of a lower-capacity, less expensive, and more compact generator.

[0020] The power supply system is advantageously complemented by the following features, taken alone or in any technically possible combination thereof: - for each rectifier circuit:

[0021] • the first branch comprises a first diode and a second diode of the same forward direction and is coupled to the first end of the respective winding between the first diode and the second diode,

[0022] • the second branch comprises a first diode and a second diode of the same forward direction, and a switch between the first diode and the second diode, the second diode being downstream of the first diode in the forward direction, the second branch being coupled to the second end of said winding between the switch and the first diode; - in the first operating mode, the switches are blocked, and in the second operating mode, the switches are open; - neither end of the stator windings is connected to another end of the stator windings; - each winding extends radially with respect to an axis of rotation of the rotor, and the first end of a winding is between the rotor and the second end of said winding; - the second ends of the windings of the electric generator would correspond to a neutral phase if said second ends were connected together; - the adaptation circuit includes a first terminal and a second terminal which are configured to be connected to the load, the three rectifier circuits being mounted in series between the first terminal and the second terminal.

[0023] The invention also relates to a turbomachine comprising a drive shaft configured to be driven in rotation during the operation of the turbomachine, and a power supply system according to the invention, comprising a three-phase electric generator configured to be driven in rotation by the drive shaft.

[0024] The invention also relates to an aircraft comprising a turbomachine according to the invention, the turbomachine being attached to a wing or fuselage of said aircraft.

[0025] The invention also relates to a method for adapting the power supply to a load by a power supply system according to the invention, wherein, when a state is determined causing a decrease in the rotation of the motor shaft or a drop in the output voltage below a voltage threshold, the adaptation circuit switches from a first operating mode in which only the first branch is conducting and where a nominal output voltage is supplied to the load, to a second operating mode in which both the first and second branches are conducting and where an output voltage of double the value nominal is supplied to the load. PRESENTATION OF THE FIGURES

[0026] The invention will be better understood from the following description, which relates to a preferred embodiment, given by way of non-limiting example and explained with reference to the accompanying schematic drawings, in which:

[0027] - [Fig. 1] is a simplified electrical diagram of a power supply system according to a possible embodiment of the invention;

[0028] - [Fig.2] shows an example of the voltages across the rectifier circuits of voltage and nominal output voltage when the switches are open according to a possible embodiment of the first operating mode of the invention;

[0029] - [Fig.3] shows an example of phase voltages and doubling of the nominal output voltage when the switches are conducting according to a possible embodiment of the second operating mode of the invention;

[0030] - Figure 4 shows an example of an aircraft equipped with turbomachinery according to a mode of possible realization of the invention

[0031] In the various figures, identical numerical references designate similar or equivalent elements. DETAILED DESCRIPTION

[0032] With reference to [Fig. 1], an example of a power supply system 1 configured to electrically supply a load 2 is described. The power supply system 1 may advantageously be part of a turbomachine. The load 2 may, in particular, be an aircraft component, and preferably a component related to essential services of a turbomachine, such as the full-authority digital engine control system (FADEC), or a possible fuel metering pump.

[0033] The power supply system 1 comprises a three-phase electric generator 4 including a rotor 6 configured to be driven in rotation by a drive shaft, and a stator 8. The electric generator 4 is typically a synchronous machine, and more specifically an alternator. The electric generator 4 converts mechanical rotational energy into electrical energy in the form of alternating electric current.

[0034] The stator 8 comprises three windings 10a, 10b, 10c, each corresponding to one phase of a three-phase current. More precisely, the three windings 10a, 10b, 10c are distributed at 120° to each other in a plane orthogonal to the axis of rotation of the rotor, and therefore each delivers a phase current that is 120° out of phase with the other phase currents.

[0035] Each winding 10a, 10b, 10c comprises a first end PI, P2, P3 and a second end NI, N2, N3 opposite the first end PI, P2, P3. Usually, a winding 10a, 10b, 10c is a conducting coil or a solenoid winding around an axis extending radially from the rotor 6, and each winding 10a, 10b, 10c extends radially with respect to the axis of rotation of the rotor 6, and the first end PI, P2, P3 of a winding is between the rotor 6 and the second end NI, N2, N3 of said winding. The first end PI, P2, P3 of a winding is on the side of the rotor 6 and the second end NI, N2, N3 is opposite the rotor 6. Thus, a first winding 10a includes a first end PI and a second end NI, a second winding 10b includes a first end P2 and a second end N2, and a third winding 10c includes a first end P3 and a second end N3.

[0036] It is the non-limiting embodiment that is illustrated and described below, but conversely, it would also be possible for the first end to be on the side of the rotor 6, and for the second end to be on the opposite side of the rotor 6, in which case it is sufficient to reverse the terms "first end" and "second end" in the rest of the description.

[0037] In this configuration, the second ends NI, N2, N3 can also be designated as cold points, as opposed to the first ends PI, P2, P3, which are designated as hot points. Normally, the second ends NI, N2, N3 are connected together and form the neutral of the electric generator 4. In this power supply system, none of the ends of the stator windings 10a, 10b, 10c 8 is connected to another end of the stator windings 10a, 10b, 10c 8. Thus, the second ends NI, N2, N3 are not connected together and do not form a neutral. Similarly, the first ends PI, P2, P3 are not connected together.

[0038] The power supply system 1 includes an adaptation circuit 1 configured to be connected in parallel with the load 2, and the first ends PI, P2, P3 and the second ends NI, N2, N3 of the windings 10a, 10b, 10c are connected to this adaptation circuit 1. The adaptation circuit 1 is configured to switch from a first operating mode in which a voltage of nominal value is supplied to the load 2 to a second operating mode in which a voltage of double the nominal value is supplied to the load 2.

[0039] To achieve this, the adaptation circuit 1 comprises three rectifier circuits 30a, 30b, 30c connected in series, each rectifier circuit 30a, 30b, 30c comprising a first branch 31a, 31b, 31c and a second branch 32a, 32b, 32c in parallel, the first branch 31a, 31b, 31c being coupled to the first end PI, P2, P3 of a respective winding 10a, 10b, 10c, and the second branch 32a, 32b, 32c being coupled at the second end NI, N2, N3 of said winding.

[0040] In detail, the first branch 3la of the first rectifier circuit 30a is connected to the first end PI of the first winding 10a, the second branch 32a of the first rectifier circuit 30a is connected to the second end NI of the first winding 10a, the first branch 31b of the second rectifier circuit 30b is connected to the first end P2 of the second winding 10b, the second branch 32b of the second rectifier circuit 30b is connected to the second end N3 of the second winding 10b, the first branch 31c of the third rectifier circuit 30c is connected to the first end P3 of the third winding 10c, the second branch 32c of the third rectifier circuit 30c is connected to the second end N3 of the third winding 10c.

[0041] The matching circuit 1 includes a first terminal 12 and a second terminal 14 which are configured to be connected to the load 2, the three rectifier circuits 30a, 30b, 30c being mounted in series between the first terminal 12 and the second terminal 14. Each branch 31a, 31b, 31c, 32a, 32b, 32c of the rectifier circuits 30a, 30b, 30c includes diodes with the same forward direction in the series arrangement of the rectifier circuits 30a, 30b, 30c, thus defining a downstream and an upstream for the electric current in the matching circuit 1. The forward direction of a diode is understood to mean the direction in which this diode allows current to flow when the diode is conducting.

[0042] In detail, the first branch 31a and the second branch 32a of the first rectifier circuit 30a are connected upstream to the first terminal 12 and thus to the load 2, and are connected downstream to the upstream of the first branch 31b and the second branch 32b of the second rectifier circuit 30b. The downstream of the first branch 31b and the second branch 32b of the second rectifier circuit 30b is connected to the upstream of the first branch 31c and the second branch 32c of the third rectifier circuit 30c. The downstream of the first branch 31c and the second branch 32c of the third rectifier circuit 30c is connected to the second terminal 14 of the matching circuit 1, and thus to the load 2.

[0043] More specifically, for each rectifier circuit 30a, 30b, 30c, the first branch 31a, 31b, 31c comprises a first diode 311a, 311b, 311c and a second diode 312a, 312b, 312c of the same forward direction and is coupled to the first end P1, P2, P3 of the respective winding 10a, 10b, 10c between the first diode 311a, 311b, 311 and the second diode 312a, 312b, 312c. For example, the first end P2 of the second winding 10b is coupled to the first branch 31b of the second rectifier circuit 30b between a first diode 311b and the second diode 312b.

[0044] For each rectifier circuit 30a, 30b, 30c, the second branch 32a, 32b, 32c comprises a first diode 321a, 321b, 321c and a second diode 322a, 322b, 322c of the same forward direction, and a switch S1, S2, S3 between the first diode 321a, 321b, 321c and the second diode 322a, 322b, 322c, the second diode 322a, 322b, 322c being downstream of the first diode 321a, 321b, 321c in the forward direction, the second branch 32a, 32b, 32c being coupled to the second end NI, N2, N3 of a respective winding between the switch SI, S2, S3 and the first diode 321a, 321b, 321c. For example, for the second rectifier circuit 30b, the second branch 32b includes a first diode 321b and a second diode 322b of the same forward direction, and a switch S2 between the first diode 321b and the second diode 322b, the second diode 322b being downstream of the first diode 321b in the forward direction, the second branch 32b being coupled to the second end N2 of the second winding 10b between the switch S2 and the first diode 321b.

[0045] Due to the coupling of the first end PI, P2, P3, and the second end NI, N2, N3 with the branches 31a, 31b, 31c, 32a, 32b, 32c of the rectifier circuits 30a, 30b, 30c, these are bidirectional when the switches SI, S2, S3 are conducting, and unidirectional when the switches SI, S2, S3 are blocking.

[0046] The switches SI, S2, S3 are configured to change state according to a control signal, between a closed state in which an electric current can flow through them, and an open state in which the electric current cannot flow through them. The switches SI, S2, S3 are typically transistors, for example insulated-gate bipolar transistors (or IGBTs), insulated-gate field-effect transistors more commonly known as MOSFETs (metal-oxide-semiconductor field-effect transistors), but the switches SI, S2, S3 can also be thyristors or electromechanical relays.

[0047] The adaptation circuit 1 is configured to switch from a first operating mode in which a voltage of nominal value is supplied to the load 2 to a second operating mode in which a voltage of twice the nominal value is supplied to the load 2. To achieve this, switches S1, S2, S3 are used: - when switches SI, S2, S3 are open, only the first branches 31a, 31b, 31c of the rectifier circuits 30a, 30b, 30c, connected to the first ends PI, P2, P3 allow current to pass when it is in the forward direction, the second branches 32a, 32b, 32c being interrupted by switches SI, S2, S3; and due to the presence of diodes 311a, 311b, 311c, 312a, 312b, 312c of the first branches 31a, 31b, 31c, the current of each phase coming from the first ends PI, P2, P3 of the windings 10a, 10b, 10c is made positive (only positive values ​​are kept) to give an output current with a voltage at a nominal value corresponding to the sum of the positive voltages of the phase voltages at each instant; - when switches SI, S2, S3 are closed, both the first branches 31a, 31b, 31c of the rectifier circuits 30a, 30b, 30c and the second branches 32a, 32b, 32c allow current to pass when it is in the forward direction; and since in each rectifier circuit 30a, 30b, 30c the first branch 31a, 31b, 31c is connected to a first end PI, P2, P3 of a winding while the second branch 32a, 32b, 32c is connected to the second end NI, N2, N3 opposite to the first end PI, P2, P3, the first branch 31a, 31b, 31c and the second branch 32a, 32b, 32c alternately conduct the current in the forward direction, resulting in an output voltage corresponding to the sum of the absolute values ​​of the phase voltages, that is to say, to a value twice the nominal value corresponding to the sum of the positive voltages of the phase voltages which would be obtained in the first mode of operation.

[0048] The coupling of the second ends NI, N2, N3 of the windings 10a, 10b, 10c to the second branches 32a, 32b, 32c makes it possible to implement a rectification of the negative parts of the sinusoidal voltages of the windings 10a, 10b, 10c. The switches SI, S2, S3 allow the choice of whether or not to implement this rectification of these negative parts.

[0049] Figure 2 shows, in volts as a function of time, an example of the positive voltages 20a, 20b, 20c and the output voltage 22 at their nominal value when the switches are open, i.e., in the first operating mode. The positive voltages 20a, 20b, 20c correspond to the voltages across each rectifier circuit 30a, 30b, 30c. The positive voltages 20a, 20b, 20c have a sinusoidal shape for half of their period and are zero for the other half. More specifically, due to diodes 311a, 311b, 311c, 312a, 312b, 312c, only the positive values ​​of each phase voltage of coils 10a, 10b, 10c are retained.Due to the series connection of the rectifier circuits 30a, 30b, 30c in parallel with the load 2, the positive voltages 20a, 20b, 20c add up to an output voltage 22 whose nominal value remains close to the maximum value taken by each positive voltage 20a, 20b, 20c, of value 1 in this example.

[0050] Figure 3 shows, in volts as a function of time, an example of the phase voltages 24a, 24b, 24c and the output voltage 26 at a value corresponding to the sum of the absolute values ​​of the phase voltages, when switches S1, S2, S3 are closed. The phase voltages 24a, 24b, 24c correspond to the voltages of the coils 10a, 10b, 10c, and therefore have a sinusoidal shape. These phase voltages 24a, 24b, 24c are rectified by the effect of the diodes, and connecting the rectifier circuits 30a, 30b, 30c in series causes the voltages to sum. The output voltage 26, whose value corresponds to the sum of the absolute values ​​of the phase voltages 24a, 24b, 24c at each instant, from double to the maximum value taken by each phase voltage 24a, 24b, 24c, that is to say, a value close to 2 in this example for a value maximum of 1 for each phase voltage 24a, 24b, 24c.

[0051] Thus, by simply closing switches SI, S2, and S3, it is possible to double the output voltage at terminals 12 and 14 of the matching circuit 1. Consequently, when the drive speed of the electric generator is sufficient, switches SI, S2, and S3 can be left open, limiting potential overvoltages. When the drive speed of the electric generator becomes insufficient, switches SI, S2, and S3 can be closed to ensure a sufficient supply voltage.

[0052] The closing command for switches SI, S2, S3 can be implemented by a computer or by simpler means, for example, analog or mechanical. The closing command for switches SI, S2, S3 can, in particular, result from the detection of a state causing a decrease in the motor shaft's rotation or from the rectified voltage falling below a voltage threshold. The mechanical speed of the motor shaft can be measured, for example, with a tachometer or a centrifugal force sensor such as an electromechanical centrifugal relay. The output voltage or a value related to it can be measured by suitable sensors (voltmeter, etc.). The measurement is compared to a first threshold (related to the voltage or speed) below which the closing command for switches SI, S2, S3 is sent to the switches.

[0053] With the closing command, the switches SI, S2, S3 of the second branches 32a, 32b, 32c of the three rectifier circuits 30a, 30b, 30c are made conducting in order to cause a doubling of the output voltage value.

[0054] Similarly, it is possible to implement a control for opening switches SI, S2, S3, for example by comparing a measurement related to voltage or speed with a second corresponding threshold, preferably different from the first threshold. With the opening control, switches SI, S2, S3 of the second branches 32a, 32b, 32c of the three rectifier circuits 30a, 30b, 30c are made to block in order to halve the output voltage value.

[0055] This strategy is particularly advantageous for dealing with an autorotation regime of a turbomachine: in the event of autorotation and therefore a significant drop in the output voltage at terminals 12, 14 of the adaptation circuit 1, the closing of switches SI, S2, S3 makes it possible to recover an output voltage high enough to guarantee the correct supply of most of the essential loads.

[0056] Previously, it was necessary to size the electric generator 4 so that it would provide a sufficient output voltage (generally between 10 and 20 V) to the essential loads in the autorotation regime, which required a heavy, bulky and expensive electric generator 4, with an oversizing which in normal operation resulted in too high a voltage (for example greater than 100-150 V).

[0057] Thanks to the proposed power supply system, the electric generator 4 can be smaller in size, since a doubling of the output voltage by the adaptation circuit 1 is possible in the autorotation regime, resulting in lower costs, reduced size, and a lower output voltage in normal operation.

[0058] Advantageously, the power supply system is installed in a tur-bomachine 101 of an aircraft 100, as illustrated in [Fig.4].

[0059] The invention is defined by the claims and is not limited to the embodiments described and shown in the accompanying figures. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Power supply system configured to electrically supply a load (2) comprising a three-phase electric generator (4) configured to be rotated by a motor shaft, the electric generator (4) comprising a rotor (6) and a stator (8), the stator (8) comprising three windings (10a, 10b, 10c) each corresponding to a phase of the electric generator (4), each winding comprising a first end (PI, P2, P3) and a second end (NI, N2, N3) opposite the first end, characterized in that the power supply system comprises an adaptation circuit (1) configured to be connected in parallel to the load (2) and comprising three rectifier circuits (30a, 30b, 30c) coupled in series, each rectifier circuit (30a, 30b, 30c) comprising a first branch (31a, 31b, 31c) and a second branch (32a, 32b, 32c) in parallel with the first branch (31a, 31b, 31c), the first branch (31a, 31b,31c) being coupled to the first end (PI, P2, P3) of a respective winding (10a, 10b, 10c), and the second branch (32a, 32b, 32c) being coupled to the second end (NI, N2, N3) of said winding, the matching circuit (1) being configured to switch from a first operating mode in which only the first branch (31a, 31b, 31c) is conductive and where an output voltage of nominal value is supplied to the load (2), to a second operating mode in which the first branch (31a, 31b, 31c) and the second branch (32a, 32b, 32c) are conductive and where an output voltage of double the nominal value is supplied to the load.,

2. A power supply system according to claim 1, wherein for each rectifier circuit (30a, 30b, 30c): • the first branch (31a, 31b, 31c) comprises a first diode (311a, 311b, 311c) and a second diode (312a, 312b, 312c) of the same forward direction and is coupled to the first end (PI, P2, P3) of the respective winding (10a, 10b, 10c) between the first diode and the second diode, • the second branch (32a, 32b, 32c) comprises a first diode (321a, 321b, 321c) and a second diode (322a, 322b, 322c) of the same forward direction, and a switch (SI, S2, S3) between the first diode (321a, 321b, 321c) and the second diode (322a, 322b, 322c), the second diode (322a, 322b, 322c) being downstream of the first diode (321a, 321b, 321c) in the forward direction, the second branch (322a, 322b, 322c) being coupled to the second end (NI, N2, N3) of said winding (10a, 10b, 10c) between the switch (SI, S2, S3) and the first diode (321a, 321b, 321c).

3. Power supply system according to claim 2, wherein in the first mode of operation, the switches (SI, S2, S3) are blocking, and in the second mode of operation, the switches (SI, S2, S3) are conducting.

4. 4. A power supply system according to any preceding claim, wherein none of the ends (PI, P2, P3) of the windings (10a, 10b, 10c) of the stator (8) is connected to another end (NI, N2, N3) of the windings (10a, 10b, 10c) of the stator (8).

5. A power supply system according to any preceding claim, wherein each winding (10a, 10b, 10c) extends radially relative to an axis of rotation of the rotor (6), and the first end of a winding (10a, 10b, 10c) is between the rotor (6) and the second end (N1, N2, N3) of said winding.

6. A power supply system according to any preceding claim, wherein the second ends (NI, N2, N3) of the windings (10a, 10b, 10c) of the electrical generator (4) would correspond to a neutral phase if said second ends (NI, N2, N3) were connected together.

7. A power supply system according to any preceding claim, wherein the matching circuit (1) comprises a first terminal (12) and a second terminal (14) which are configured to be connected to the load (2), the three rectifier circuits (30a, 30b, 30c) being connected in series between the first terminal (12) and the second terminal (14).

8. A turbomachine (101) comprising a drive shaft configured to be driven in rotation during operation of the turbomachine, and a power system according to any one of the preceding claims, comprising a three-phase electric generator (4) configured to be driven in rotation by the drive shaft.

9. Aircraft (100) comprising a turbomachine (101) according to claim previous indication, the turbomachine being attached to a wing or a fuselage of said aircraft.

10. A method for adapting a power supply to a load (2) by a power supply system according to any one of claims 1 to 7, wherein when a condition causing a decrease in rotation of the motor shaft or a lowering of the output voltage below a voltage threshold is determined, the adaptation circuit (1) switches from a first operating mode in which only the first branch (31a, 31b, 31c) is conductive and an output voltage of nominal value is supplied to the load (2), to a second operating mode in which the first branch (31a, 31b, 31c) and the second branch (32a, 32b, 32c) are conductive and an output voltage of twice the nominal value is supplied to the load.

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