MULTI-SOURCE ELECTRIC MACHINE AND ASSOCIATED METHODS

Description

Domaine technique

[0001] The present invention relates to a multi-source system. It also relates to a method for controlling said multi-source system. The invention targets fields such as: the generation of onboard networks in aeronautics, the field of wind turbines, or inertial storage associated with multiple networks. Etat de la technique antérieure

[0002] In typical "multi-source" solutions, power transfer between sources occurs via mechanical forces. However, this introduces disturbances in radial forces or torque ripples within the machine. Indeed, these mechanical phenomena induce vibrations and reduce the lifespan of mechanical components. Furthermore, in these structures, power transfer between sources is limited by the considered torque / speed operating point. This transfer also introduces inhomogeneities in the magnetic flux density within the machine, resulting in additional losses.

[0003] There are two categories of structures that allow the exchange of energy between sources through mechanical forces: 1) Structures subdivided into sectors, based on the number of pole pairs in the machine. This is referred to as a sectorized machine. This subdivision allows for several electrically independent and weakly magnetically coupled three-phase subsystems. Thus, the power transfer between the different sources unnecessarily increases the induction level in the machine and disrupts the radial forces. The radial forces can be compensated by adding currents along the direct axis of the magnetic flux in the machine. All these factors make the power transfer between three-phase subsystems in these structures complex, generate losses, and be accessible only over a limited operating range. 2) Multi-phase structures subdivided into several independent subsystems with a prime number of phases.The total number of phases is therefore not a prime number for allowing the use of multiple power sources. Generally, a solution with several three-phase systems is used for industrial standardization reasons. This is referred to as a multi-three-phase machine. This subdivision allows for several electrically independent and moderately magnetically coupled three-phase subsystems. Thus, the power transfer between the different sources also induces inhomogeneities in the magnetic induction circuit of the machine (and therefore an increase in iron losses) and disturbs the torque harmonics.

[0004] The document US2021 / 075284 A1 describes a multi-source system.

[0005] The aim of the present invention is to resolve at least one of these drawbacks. Exposé de l'invention

[0006] This objective is achieved with a multi-source system comprising an electric machine, of the type comprising a rotor and a stator, the stator comprising a plurality of windings made of windings of insulated conductive material, each winding comprising a plurality of independently powered coils, characterized in that the system also comprises a plurality of continuous power sources and a plurality of power electronics converters associated with different coils of the electric machine, each power source supplying one or more power electronics converters and each power source being connected to at least one coil of each winding of the electric machine.

[0007] The proposed invention improves the use of an electrical machine in a multi-source power supply context by decoupling power transfer between sources from the mechanical aspect. According to the invention, power transfer occurs primarily through electromagnetic phenomena and without the associated mechanical disturbances. Power transfer ranges are extended, and conversion efficiency is improved. The invention also increases the degree of freedom in the number of power sources interconnected through the electrical machine.

[0008] The invention is equivalent to traditional structures in terms of manufacturing complexity. However, it extends the achievable power transfer range and improves power transfer efficiency. Finally, it allows for the connection of a greater number of sources than any other solution.

[0009] The coils of the same winding are powered by signals of the same phase and the stator includes slots.

[0010] Each slot includes the coils of the same winding, and the coils of the same winding are powered by separate power sources.

[0011] A winding according to the invention can be "distributed / distributed" or "dental / concentric" or even "fractional pitch" depending on the embodiment.

[0012] The plurality of windings can be distributed into at least two zones.

[0013] The at least two zones may correspond to electrical machine sectors. The at least two zones may correspond to systems m p - phased electrical machine. The term "sectors" refers to areas of the electrical machine corresponding to at least one pair of magnetic poles of the stator.

[0014] The at least two zones can be split, each fraction of each zone being associated with a power electronics converter, the fraction and its power electronics converter constituting an elementary building block of electromechanical conversion.

[0015] Each basic mechanical conversion building block can be associated with a power source.

[0016] Generally speaking, a generic machine possessing m phases, p pairs of stator poles with Ns turns per pole and per phase can lead to the use of a number p × k B of electromechanical conversion bricks (inverter and fraction grouping) where k B is an integer divisor of Ns. If m is not a prime number, such that m = n × m p It is also possible to separate the m phases in n systems m p - phased. Leading in total to p × n × k B Basic building blocks. The basic building block of electromechanical conversion may involve a prime number m p of phases. In most cases, this prime number is worth m p = 3.

[0017] A basic building block of electromechanical conversion includes a system m p -phased coil associated with its own static power electronics converter (inverter). The converter is connected to one of the system's DC sources, delivering a voltage U DC,i Among the ways to configure the converter with these m p reels, we find two configurations:

[0018] In the first one, the converter has m p Inverter arms, each associated with a coil. The coils share a common potential called the "neutral". This neutral imposes a zero zero-sequence current in the structure.

[0019] In the second configuration, the converter has m p Complete inverter bridges, each associated with a coil. There is no neutral point, therefore twice as many switches are required, and it is necessary to control the zero-sequence component. This component does not affect the torque but can be used for power transfer between sources.

[0020] The invention proposes a winding splitting method that allows the problems of mechanical force distribution (torque harmonics or radial forces) to be separated from those of energy transfer between the sources. To achieve this, the multi-source structure must exhibit k B sources, each source feeding pn converters, with all converters associated with each source connected to a coil of each winding of the electrical machine. Controlling torque harmonics and radial forces is relevant in certain applications (respectively, those with low torque ripple or "bearingless" operation). Therefore, to maintain these means of action / control, the invention proposes combining the division of a winding into a plurality of coils with subdivision into zones such as sectors or multi-phase systems, and hierarchically organizing the control structure to maintain decoupling between energy transfer and mechanical forces.

[0021] The systems m p -phased systems may correspond to m p -electric machine phases that are time-shifted by an electrical angle that is not a multiple of 60°. This corresponds to multi-phase structures with a number of electrically distinct phases that is a multiple of three.

[0022] The number of coils in a winding can be greater than or equal to the number of power sources. For example, if the system has two power sources, the number of coils in a single winding must be greater than or equal to two. If there are three power sources, the number of coils in a single winding must be greater than or equal to three.

[0023] The windings can have a number of turns that is a multiple of the number of power sources. For example, if the system has two power sources, the number of turns in each winding is a multiple of two. If there are three power sources, the number of turns in each winding is a multiple of three.

[0024] According to yet another aspect of the invention, a control method is proposed, applied to a multi-source system according to the invention by at least one control circuit, the method comprising the following steps: The first stage involves distributing the currents from the plurality of power sources to at least one zone of the electrical machine, and the second stage involves distributing the currents to at least a fraction of each zone. The two stages of the process are independent of each other.

[0025] The distribution of currents to each zone of the electrical machine determines the mechanical state (torque and stress). The distribution of currents to each fraction of each zone determines the power transfers between sources.

[0026] The distribution of current to each zone can be determined based on radial force requirements or torque harmonics. It is also possible to use current distribution to each zone based on energy exchange needs between different power sources. The primary application where controlling radial forces is necessary is when it is required to mitigate the forces applied to mechanical bearings or to ensure complete magnetic levitation of the rotor. Radial forces are applied by the stator and its conductors to the rotor to magnetically center the rotor or simply to limit the radial forces that the rotor applies to the bearings.

[0027] In a multi-source system, it is necessary to manage the power drawn from each source and, more generally, to manage the power exchanges between the different sources to ensure their balance or any other function required by energy monitoring. The overall energy management of the system is ensured through the machine.

[0028] The distribution of at least one current to each fraction of each zone can be carried out according to the energy exchange requirements between the different power sources. This ensures the balancing of power sources and, more generally, controls the energy supplied to or absorbed by them.

[0029] When each power source supplies a power electronics converter, the process may include the following step: direct distribution of currents from the plurality of power sources to at least a fraction of the electrical machine.

[0030] The distribution of currents from the plurality of power sources to at least one fraction can be balanced.

[0031] In this embodiment, each source feeds a single power converter.

[0032] The invention employs an arrangement of the various elementary windings to maximize their magnetic coupling. Power transfer between the different sources is electromagnetic, with a reduced mechanical impact on the rotor. The two functions of torque generation and inter-source power transfer are, by design, made virtually independent. Consequently, torque generation and radial forces do not depend on power transfer between the sources. The magnetic induction level depends only on the torque operating point and therefore does not depend on power transfer between the sources. Iron losses on the machine side are thus reduced in our solution. Power transfer capabilities are increased near the base speed.

[0033] The process may also include the following step: introduction of an additional current component evolving at an arbitrary frequency.

[0034] Power transfer occurs at this arbitrary frequency, allowing it to be decoupled from the mechanical operating point. This notably enables power transfer between sources when the rotor is locked, whereas standard autopilot would produce continuous values ​​at a standstill, incompatible with electromagnetic power transfer.

[0035] The process may also include a control step allowing at least a fraction of the electrical machine to be activated and / or deactivated for a period of time T.

[0036] The distribution of currents from the plurality of power sources to at least a fraction can also be achieved as a function of a switching frequency of one or more of the power electronic converters. Description des figures et modes de réalisation

[0037] Other advantages and features of the invention will become apparent upon reading the detailed description of implementations and embodiments, which are by no means limiting, and the following attached drawings: There figure 1a illustrates an electrical machine in a three-phase version according to the invention. figure 1b illustrates a magnified view of the electrical machine of the figure 1a . There figure 2a presents a multi-source system with radial force control according to a first embodiment. figure 2b presents a multi-source system with radial force control according to a second embodiment. figure 3 illustrates the control process applied to the multi-source system of the figure 2b . There figure 4a illustrates a multi-source system with torque ripple control according to a first embodiment. figure 4b illustrates a multi-source system with torque ripple control according to a second embodiment. figure 5 illustrates the control process applied to the multi-source system of the figure 4b . There figure 6 illustrates a multi-source system with control of torque ripples and radial forces. figure 7 illustrates the control process applied to the multi-source system of the figure 6 . There figure 8 illustrates the control process applied to a multi-source system according to another embodiment.

[0038] These embodiments are not exhaustive; in particular, variants of the invention may be considered that comprise only a selection of features described or illustrated hereafter, isolated from the other described or illustrated features (even if this selection is isolated within a sentence including these other features), provided that this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection includes at least one preferably functional feature without structural details, and / or with only a portion of the structural details if this portion alone is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0039] In the following description, the term "electrical machine" is used to refer to an electrical machine that transforms electrical energy into mechanical energy (motor) but also its reverse (generator). The principle of the present invention can be applied to all types of electrical machines, such as synchronous, asynchronous, variable reluctance, etc. The type of electrical machine depends on the rotor used.

[0040] In general, we consider a generic machine possessing m phases, p pairs of stator poles with Ns turns per pole and per phase. If m is not a prime number, such that m = n × m p It is also possible to separate the m phases in n systems m p -phased. It is assumed that within each slot, the windings are divided into k B coils. This structure allows the energy management to be decoupled from the generation of radial forces while ensuring that the machine's magnetic circuit is used homogeneously during energy exchanges.

[0041] There figure 1a represents an electrical machine according to the invention. figure 1b represents a magnified view of the electrical machine of the figure 1a An electrical machine consists of a rotor (not shown) and a stator 1 comprising windings in slots 10, 11, 12. Here, the three windings 10, 11, 12 belong to the same phase A+. The windings 10, 11, 12 are divided into a plurality of coils 100, 101 and 102, 110, 111, 112 and 120, 121, 122. Each coil 100, 101 and 102, for example, of the same winding 10 has its own terminals through which it is supplied.

[0042] In the example of figures 1a ) and b), each winding 10, 11, 12 was split into three coils 100, 101 and 102, 110, 111, 112 and 120, 121, 122. Each phase A+ / -, B+ / -, C+ / - is split into k B magnetically coupled sub-phases (the electromagnetic field lines generated by coils of the same winding are oriented in the same direction), and thus constitutes k B electrical submachines (in the figure 1a The electrical submachines are respectively composed of the coils [102, 112, 122], [101, 111, 121], and [100, 110, 120]. This division therefore amounts to positioning blocks of turns in parallel rather than in series, in order to be able to supply them with separate power supply signals having lower voltages. The coils of the same winding are then mechanically (but not electrically) in parallel within the same winding. Being supplied by signals of the same phase, the ampere-turns they generate are additive. In the example shown in figures 1a ) and b), the coils constituting a single winding are arranged one after the other, but they could also be interlaced, mixed, or superimposed, without prejudice to the invention.

[0043] In other words, the coils 100, 101, 102 of the same winding 10, 11, 12 can be powered by signals of the same phase. The stator 1 has slots a, b, c; a', b', c' and a", b", c". Furthermore, each slot can contain the coils 100, 101, 102 of the same winding 10, 11, 12. Moreover, the coils 100, 101, 102 of the same winding can be powered by separate power supplies 2.

[0044] On the figures 1a, 1b , 2a , 2b , 4a , 4b , And 6One embodiment of the slots is shown. Each slot can hold at least two coils of the same winding. For example, each slot contains three coils 100, 101, 102 of the same winding 10, 11, 12. A slot forms a housing for several coils. Each slot extends longitudinally along an axis, called a radial axis, associated with the slot. Each radial axis is oriented towards the center of the machine, that is, towards the center of the rotor. A radial axis extends along a radius of the machine's rotor and passes through the slot to which the radial axis is associated.

[0045] Generally, within the same slot, the coils of the same winding can be arranged one after the other, or they can also be interlaced, mixed, or superimposed. For example, as illustrated on the figure 1b The coils of the same winding can be stacked within the same slot. That is to say, the coils of the same winding housed within the same slot can be aligned radially along the radial axis associated with the slot.

[0046] For example, a notch a, b, c, and preferably each notch, is associated with a phase A+ / -, B+ / -, C+ / -. Furthermore, each notch a, b, c is associated with a winding 10, 11, 12. Moreover, each coil of the same winding comprises two terminals, first and second, through which the coil is energized. For example, each coil of the same winding comprises a first terminal located at a first part A+, B+, C+ of the housing formed by a notch a, b, c, and a second terminal located at a second part A-, B-, C- of the housing formed by the notch a, b, c.

[0047] THE figures 1a et 1b describe precisely an electrical machine comprising a nine-phase stator, either with m= n × m p = 9 with m p = 3, each phase having three pairs of poles ( p = 3). The stator consists of eighteen slots per pole pair, for a total of fifty-four; therefore, in its standard three-phase form, each phase is distributed over three consecutive slots. Each slot is considered to contain three coils or conductors or groups of conductors ( k B = 3). Each coil or conductor is associated with a rank: rank 1, rank 2, or rank 3, with rank 1 being characterized by the position closest to the rotor (center of the electric machine). The electric machine under consideration therefore corresponds to n = p = k B = 3. The "+" conductors go into the stator, the "-" conductors come out of it.

[0048] The electrical machine can be connected to a plurality of power sources, each power source being connected to a plurality of power converters. The DC power source supplying each power converter is a DC or rectified voltage source delivering a voltage U Q,i Each converter includes a control circuit. The electrical machine is used as a reference to illustrate the different embodiments of the invention. However, the electrical machine of the figures 1a ) and b) does not limit the present invention to this application. This application is given by way of example. In other embodiments, k B can be equal to two, for example (see the figures 2a And 4a ).

[0049] THE figures 2a And 2bpresent a multi-source system with radial force control, without coupling between the energy management and radial force management functions.

[0050] We consider a structure that allows us to associate k B energy sources for an electrical machine. Each source powers p converters, each associated with distinct pole pairs of the machine. These different pole pairs are represented by different shades of gray in the following figure. They are also separated by dashed lines.

[0051] The electric machine of figures 2a And 2b is divided into three zones or sectors (S1, S2, S3) corresponding to the three pairs of poles of said machine. According to the figure 2a The multi-source system therefore comprises an electrical machine M as described previously, along with a plurality of power sources 2 and a plurality of power converters 3. The electrical machine M is connected to two sources 2: U and V. Each source 2 is associated with three power converters 3. Consequently, six power converters 3 are used in total. Here, two power sources 2 are used. k b = 2. For each power supply 2, the first converter 3 is associated with the first pair of stator poles (zone S1) symbolized by phases A1+ / -, B1+ / -, and C1+ / -. The second converter is associated with the second pair of stator poles (zone S2) symbolized by phases A2+ / -, B2+ / -, and C2+ / -. The third converter is associated with the third pair of stator poles (zone S3) symbolized by phases A3+ / -, B3+ / -, and C3+ / -. Source U supplies the first-order coils in each zone, and source V supplies the second-order coils in each zone.

[0052] According to the figure 2b , and on the same principle as for the figure 2a The multi-source system comprises an electrical machine M as described previously, along with a plurality of power sources 2 and a plurality of power converters 3. The electrical machine M is connected to three sources 2: U, V, and W. Each source 2 is associated with three power converters 3. Therefore, a total of nine power converters 3 are used. Here, three power sources 2 are used because k B =3. For each power supply 2, the first converter 3 is associated with the first pair of stator poles (zone S1) symbolized by phases A1+ / -, B1+ / -, and C1+ / -. The second converter is associated with the second pair of stator poles (zone S2) symbolized by phases A2+ / -, B2+ / -, and C2+ / -. The third converter is associated with the third pair of stator poles (zone S3) symbolized by phases A3+ / -, B3+ / -, and C3+ / -. Source U supplies the first-order coils in each zone, source V supplies the second-order coils in each zone, and source W supplies the third-order coils in each zone. In other embodiments, it is possible to mix rows and zones for the same supply, for example row 1 of zone 1, row 2 of zone 2 and row 3 of zone 3 are associated with the same source.

[0053] According to the figure 3 We will now describe the control process applied to the multi-source system of the figure 2b The control method according to the invention is applied by each control circuit of each converter 3 of the system. In another embodiment, the method can be applied by a general control circuit to all converters 3, for example. The method comprises the following steps: first distribution of currents from the plurality of power sources to at least one zone of the electrical machine, second distribution of currents to at least a fraction of each zone.

[0054] The two stages of the process are independent of each other regardless of the embodiment. The windings of the electric machine are divided into three zones, here corresponding to sectors: sectors S1, S2 and S3 as represented by the dashed lines on the figure 2b Sectors S1, S2, and S3 correspond to well-defined zones of the electrical machine M. Sector S1 comprises phases A1+ / -, B1+ / -, and C1+ / -. Sector S2 comprises phases A2+ / -, B2+ / -, and C2+ / -. Sector S3 comprises phases A3+ / -, B3+ / -, and C3+ / -.

[0055] The sectors S1, S2, and S3 are then subdivided. Each subdivision is associated with at least one phase of the electrical machine. Here, the subdivisions group one coil from each phase A1, B1, and C1 for sector S1, one coil from each phase A2, B2, and C2 for sector S2, and one coil from each phase A3, B3, and C3 for sector S3. The control method is applied in the same way to the multi-source system described in the figure 2a only the number of power sources differs.

[0056] According to the figure 3 , starting from the operating point in terms of torque and flux to be achieved and as a function of speed, the reference currents I dq The currents to be applied are expressed in the Park reference frame; they correspond to the currents that would be found in the reference electrical machine (see Figs. 1a,1b Based on the required radial forces to be applied, these currents are distributed into I dq 1, I dq2 And I dq 3 towards each of the sectors S1, S2, S3 depending on K xy 1, K xy 2 and K xy 3. These currents I dq 1, I dq 2 and I dq 3 are then split into the three fractions (1u, 1v, 1w), (2u, 2v, 2w) and (3u, 3v, 3w) of each sector S1, S2, S3 according to energy exchange requirements K pu , K pv And K pw between the U, V and W sources.

[0057] For example, and in the case where the three voltages U Qi If the forces are equal, to exert a radial force on the rotor to pull it to the right, sector S3 must work harder than the other two. Therefore, a 25% / 25% / 50% power distribution of the total power for the three sectors can be adopted. Furthermore, if there is a need for energy management where source U is the most heavily used, a 50% / 25% / 25% power distribution of the total power between the sources can be adopted.

[0058] Therefore, of the 25% allocated to sector S1, 12.5% ​​will be in rank 1, and 6.25% in ranks 2 and 3 (12.5 + 2 * 6.25 = 25). Of the 25% allocated to sector S2, 12.5% ​​will be in rank 1, and 6.25% in ranks 2 and 3 (12.5 + 2 * 6.25 = 25). Of the 50% allocated to sector S3, 25% will be in rank 1, and 12.25% in ranks 2 and 3 (25 + 2 * 12.5 = 50). K xy 1, K xy 2 and K xy 3 correspond to the percentages associated with each sector S1, S2, S3. K pu , K pv And K pw correspond to the percentages of the total power that are assigned to each source U, V, W.

[0059] Starting from the electrical machine M, we use the degrees of freedom k B And p to interconnect sources without the energy transfers between sources disrupting the radial forces in the machine. The use of p = 3 power converters per source allows to maintain the degree of freedom for the active control of radial forces.

[0060] Whether it's at the figure 2a or to the figure 2b Each source is ultimately associated with windings located all around the machine, which allows the use of the different sources to be managed without generating radial forces on the rotor. However, with a suitable control hierarchy, it is still possible to use the structure's degrees of freedom to generate radial forces and achieve magnetic centering without causing an imbalance between the sources. First, the contribution in terms of forces from each sector (or pair of poles) must be determined, and then the distribution of source usage must be managed, ensuring it is the same across the different sectors. This process is applicable regardless of the characteristics ( n , p ) of the machine. The number of notch subdivisions k B may be greater than or equal to the number of sources.

[0061] There figure 4a presents a multi-source system with torque ripple control according to a first embodiment. The electrical machine of figures 4a And 4b is divided into three zones or three-phase systems on the same principle as the figures 2a And 2b These three three-phase systems correspond to the three pole pairs of said machine.

[0062] According to the figure 4a The electrical machine M is connected to two sources 2: U and V. Each source 2 is associated with three power converters 3. Each converter is associated with areas of the electrical machine corresponding to systems m p -distinct phases. These different systems m p The phases are offset by an electrical angle, the electrical angle being equal to 20 degrees. The angle is equal to 20 degrees in this embodiment because the example includes eighteen slots per pair of poles (360 / 18=20). The system m p The phase associated with the first converter of each source is linked to notch a of phase A+ / -, notch b of phase B+ / -, and notch c of phase C+ / -, which is the first notch of each of the aforementioned phases. The second converter of each source is linked to the second notches a', b', and c' of the aforementioned phases. The third converter of each source is linked to the third and final notches a", b", and c" of the aforementioned phases. Source U supplies the first-order coils in each zone, and source V supplies the second-order coils in each zone. In other embodiments, it is possible to mix the order and zone for the same power supply; for example, order 1 of zone 1 and order 2 of zone 2 are linked to the same source.

[0063] There figure 4b presents a multi-source system with torque ripple control, without coupling between the "energy management" and "torque ripple" management functions. According to the figure 4b We consider a structure that allows us to associate k B energy sources for an electrical machine. Each source powers n converters, each of which is associated with zones of the electrical machine corresponding to systems m p -distinct phases. These different systems m p - The phases are offset by a certain electrical angle and represented with different shades of color in the following figure. This offset is indicated by dashed lines at one pole of phase A.

[0064] According to the figure 4b , and on the same principle as for the figure 4a The electrical machine M is connected to three sources 2: U, V, and W. Each source 2 is associated with three power converters 3. Each converter is associated with systems m p -distinct phases. These different systems m p The phases are offset by an electrical angle, the electrical angle being equal to 20 degrees. The angle is equal to 20 degrees in this embodiment because the example includes eighteen slots per pair of poles (360 / 18=20). The system m p The phase associated with the first converter of each source is linked to notch a of phase A+ / -, notch b of phase B+ / -, and notch c of phase C+ / -, which is the first notch of each of the aforementioned phases. The second converter of each source is linked to the second notches a', b', and c' of the aforementioned phases. For the third converter of each source, it is associated with the third and final slots a", b", and c" of the aforementioned phases. Source U powers the first-order coils in each zone, source V powers the second-order coils in each zone, and source W powers the third-order coils in each zone. In other embodiments, it is possible to mix the orders and zones for the same power supply; for example, order 1 of zone 1, order 2 of zone 2, and order 3 of zone 3 are associated with the same source.

[0065] According to the figure 5 We will now describe the control process applied to the multi-source system of the figure 4b The control method according to the invention is applied by each control circuit of each converter 3 of the system. In another embodiment, the method can be applied by a general control circuit to all converters 3, for example. As previously described, the method comprises the following steps: First, the currents from the plurality of power sources are distributed to at least one zone of the electrical machine; second, the currents are distributed to at least a fraction of each zone. The windings of the electrical machine M are distributed into three zones corresponding to three-phase systems or systems m p -phased, each three-phase system being associated with a 3-transformer.

[0066] The three-phase systems associated with each converter are then divided. Each division corresponds to separate coils of the windings that make up the three-phase systems of the electrical machine. Here, for each source, the first converter supplies a fraction of the area corresponding to slots a, b, c; the second converter supplies a fraction of the area corresponding to slots a', b', c'; and the third converter supplies a fraction of the area corresponding to slots a", b", c". From the operating point in terms of torque and flux to be achieved, i.e., the speed, the reference currents I dq The currents to be applied are expressed in the Park reference frame; they correspond to the currents that would be found in the reference electrical machine ( Figs. 1a, 1b To minimize torque ripple, these currents I dq are divided into I dq , I' dq And I" dq to each of the three-phase systems depending on K h , K' h , K" h The currents I dq , I' dq And I" dq are then split into the three fractions (u, v, w), (u', v', w') and (u", v", w") of each three-phase system according to energy exchange requirements K pu , K pv And K pw between the U, V, and W sources. Advantageously, to minimize the ripple of the torque applied to the rotor in healthy mode, the three systems must be m p -phased work equally, or in a balanced way. For example, and in the case where the three voltages U Qi are equal, the distribution can be 33% / 33% / 33% of the total power for the three systems m p -phased. Then, if there is a need for additional energy management, such as when source U is the most heavily used, a 50% / 25% / 25% distribution of the total power between the sources can be adopted. Therefore, of the 33% allocated to the first system m p -phased, there will be 16.7% in rank 1, and 8.4% in ranks 2 and 3 (16.7 + 2 * 8.4 = 33). The same applies to the other two zones. Starting from the electrical machine M, we use the degrees of freedom k B And n to interconnect sources without the energy transfers between sources disturbing the torque ripples in the machine. The use of n = 3 power converters per source allows to maintain the degree of freedom for active control of torque ripples.

[0067] Whether it's at the figure 4a or to the figure 4b The converters associated with each source ultimately power windings corresponding to zones within systems m p -phased, which allows for managing the use of different sources without degrading the harmonics of the pair. This is made possible by a suitable control hierarchy: First, the harmonic control between the different systems must be established. m p -phased and then manage the distribution of resource usage, which will be the same across the different systems m p -phased. This process is applicable regardless of the characteristics ( n , p ) of the machine and the number of notch subdivisions k B . Preferably, k b is greater than or equal to the number of sources. Advantageously, k b is equal to the number of sources in the system. The control method described applies in the same way to the multi-source system described in the figure 4a .

[0068] With reference to the figure 6 We will describe a multi-source system with control of torque ripples and radial forces, without coupling between the energy management and mechanical force management functions. The electric machine of the figure 6 is divided into three zones or sectors (S1, S2, S3) corresponding to the three pairs of poles of said machine.

[0069] The electrical machine M is connected to three sources 2: U, V, and W. Each source 2 is associated with three power converters 3. For each power source 2, the first converter 3 is associated with the first pair of stator poles (zone S1), symbolized by phases A1+ / -, B1+ / -, and C1+ / -. The second converter is associated with the second pair of stator poles (zone S2), symbolized by phases A2+ / -, B2+ / -, and C2+ / -. The third converter is associated with the third pair of stator poles (zone S3), symbolized by phases A3+ / -, B3+ / -, and C3+ / -. The pole pairs are associated with three-phase systems offset by an electrical angle of 20 degrees. The angle is equal to 20 degrees in this embodiment because the example includes eighteen notches per pair of poles (360 / 18=20).Source U powers the first-order coils in each zone, source V powers the second-order coils in each zone, and source W powers the third-order coils in each zone. In other embodiments, it is possible to mix the order and zone for the same power supply; for example, order 1 of zone 1, order 2 of zone 2, and order 3 of zone 3 are associated with the same source.

[0070] According to the figure 7 We will now describe the control process applied to the multi-source system of the figure 6 The control method according to the invention is applied by each control circuit of each converter 3 of the system. In another embodiment, the method can be applied by a general control circuit to all converters 3, for example. As described above, the method comprises the following steps: first distribution of currents from the plurality of power sources to at least one zone of the electrical machine, second distribution of currents to at least a fraction of each zone.

[0071] The windings of the electrical machine M are divided into three zones corresponding to sectors: sectors S1, S2 and S3 as represented by the dotted lines on the figure 6 Sectors S1, S2, and S3 correspond to well-defined zones of the electrical machine M. Sector S1 comprises phases A1+ / -, B1+ / -, and C1+ / -. Sector S2 comprises phases A2+ / -, B2+ / -, and C2+ / -. Sector S3 comprises phases A3+ / -, B3+ / -, and C3+ / -. In this embodiment, the three sectors defined by the dashed lines have phases that are offset by an electrical angle, the electrical angle being equal to 20 degrees (see explanation in the embodiment of the preceding figures).

[0072] The zones corresponding to sectors S1, S2, and S3 are then subdivided. Each subdivision is associated with a phase of the electrical machine. Here, the subdivisions group one coil from each phase A1, B1, C1 for sector S1, one coil from each phase A2, B2, C2 for sector S2, and one coil from each phase A3, B3, C3 for sector S3. From the operating point in terms of torque and flux to be achieved, the reference currents I dq The currents to be applied are expressed in the Park reference frame; they correspond to the currents that would be found in the reference electrical machine ( Figs. 1a, 1b To minimize torque ripples and apply the desired radial forces, these currents I dq are divided into I dq 1, I dq 2 and I dq 3 towards each of the sectors depending on K xy 1, K xy 2 and K xy 3. Currents I dq 1, I dq 2 and I dq 3 are then split into the three fractions (1u, 1v, 1w), (2u, 2v, 2w) and (3u, 3v, 3w) of each three-phase system according to energy exchange requirements K pu , K pv And K pw between the sources U, V, and W. For example, and in the case where the three voltages U Qi If the currents are equal, to exert a radial force on the rotor to pull it to the right, sector S3 must work harder than the other two on the d-axis of the Park reference frame. A 25% / 25% / 50% current distribution on the d-axis for the three sectors can therefore be adopted. For the q-axis, an equal distribution must be maintained to guarantee minimal torque ripple; a 33% / 33% / 33% current distribution on the q-axis for the three sectors can therefore be adopted. Furthermore, if there is a need for energy management where source U is the most heavily loaded, a 50% / 25% / 25% distribution of the total power between the sources can be adopted. Therefore, of the 25% allocated to sector S1 according to the currents in axis d, 12.5% ​​will be in rank 1, and 6.25% in ranks 2 and 3 (12.5 + 2 * 6.25 = 25). Of the 33% allocated to sector S1 for the currents in axis q, 16.7% will be in rank 1, and 8.4% in ranks 2 and 3 (16.7 + 2 * 8.4 = 33). Therefore, of the 25% allocated to sector S2 according to the currents in axis d, 12.5% ​​will be in rank 1, and 6.25% in ranks 2 and 3 (12.5 + 2 * 6.25 = 25). Of the 33% allocated to sector S2 for the currents in axis q, 16.7% will be in rank 1, and 8.4% in ranks 2 and 3 (16.7 + 2 * 8.4 = 33). Of the 50% allocated to sector S3 according to the currents in axis d, 25% will be in rank 1, and 12.25% in ranks 2 and 3 (25 + 2 * 12.5 = 50). Of the 33% allocated to sector S3 for currents in the q axis, there will be 16.7% in rank 1, and 8.4% in ranks 2 and 3 (16.7 + 2 * 8.4 = 33).

[0073] Starting from the three-phase machine M, we use the degrees of freedom k B , n and p to interconnect sources without the energy transfers between sources disturbing the torque ripples in the machine. The use of n = p= 3 power converters per source allows to retain the degree of freedom for the active control of torque harmonics and radial forces.

[0074] As presented to the figure 8 The method of the present invention can also be applied to a system comprising several power sources 2, each power source being connected to a single converter 3. Indeed, such a system comprises an electrical machine M as described in the figure 1 For example, a plurality of power sources 2, each connected to a single power converter 3. The electrical machine M is connected to three sources 2: U, V, and W. For each power source 2, the converter 3 is associated with the pole pairs of phases A+ / -, B+ / -, and C+ / -. Source U supplies the pole pairs of rank 1, source V supplies the pole pairs of rank 2, and source W supplies the pole pairs of rank 3. In other embodiments, it is possible to mix ranks and zones for the same power supply; for example, rank 1 of zone 1 and rank 2 of zone 2 are associated with the same source.

[0075] The control method applied to this particular multi-source system is implemented by each control circuit of each converter 3. In another embodiment, the method can be applied by a general control circuit to all converters 3, for example. The method then comprises the following steps: direct distribution of currents from the plurality of power sources to at least a fraction of the electrical machine.

[0076] In this embodiment, the electrical machine is directly divided into sections. Each section is associated with a phase of the electrical machine. Here, the sections correspond to the windings of phases A, B, and C.

[0077] Starting from the target operating point in terms of torque and flux, the reference currents I dq The currents to be applied are expressed in the Park reference frame; they correspond to the currents that would be found in the reference electrical machine ( Figs. 1a et 1b These currents I dq are then distributed to the three subdivisions I dq * K pu , I dq * K pv et I dq * K pw depending on energy exchange needs K pu , K pv And K pw between the U, V and W sources. P uv And P vw are the powers exchanged between sources U and V and between sources V and W, respectively.

[0078] The invention also relates to four variations of control methods applicable to the structures described above, depending on the desired outcome. These variations concern only the electrical machine's segmentation step, that is, the distribution of currents to each segment of each zone. These variations are also applicable even if the machine is not subdivided into zones and is only divided into several rows within the slots. This distribution enables power transfer between sources. either based on the rotation frequency of the magnetic field produced by the machine's rotor, or based on an arbitrary frequency by PWM control of the inverters, or based on a sequential activation / deactivation of the subdivisions, or based on the switching frequency of the inverters by adjusting the phase shift of the PWM carriers.

[0079] Variations of the control method can be applied to electrical machines involving multiple fractions within the same stator slots (for a distributed winding) or around the same stator teeth (for a concentrated winding). These variations can also be applied to structures with at least two fractions in their slots. The variations address the interactions between highly coupled subdivisions. They enable the control of power converters associated with separate sources but whose windings share the same slots.

[0080] The first variant for decoupling inter-source power transfer and managing radial forces (Structural Feature) was introduced previously through the distribution of power directed to each zone. For example, in the case where the three voltages U Qi are equal, if there is a need for energy management such that source U is the most heavily used, a 50% / 25% / 25% distribution of the total power between the sources can be adopted. Then, in each zone, 50% of the power is directed to rank 1, 25% of the power to rank 2, and 25% of the power to rank 3. This first variant has been used throughout the description of the embodiments. This can be generalized for any number of highly coupled subdivisions. k B .

[0081] Regarding the second variant for power transfer between sources at an arbitrary frequency, the autopilot allows setting the average duty cycle applied in PWM to k B Power converters are controlled using the electrical angle. This angle is obtained through measurement using a position sensor or via an estimator enabling "position sensorless" control. In the case where the three voltages U Qi Since the torque contribution of each fraction is equal, and balanced at 33% / 33% / 33%, the process assigns an initial duty cycle value to control the equitable distribution of current within each fraction. An additional current component, operating at an arbitrary frequency, is introduced to transfer energy between the different subdivisions. This arbitrary frequency cannot be equal to the electrical frequency associated with the rotation of the electric machine M. This principle can be generalized to any number of highly coupled subdivisions. k B .

[0082] Regarding the third variant for the control method for sequential management of source usage based on conventional machine control, only one conventional machine control is implemented, instead of having k B >1. This distributes the same three-phase PWM signals to k B Power converters each have their own control circuit. The only degree of freedom used to manage the different power converters is the "enable" signal, which is associated with the control circuits of the various power converters and which allows them to be put into the "High-Impedance" state or not. This simplicity is made possible by the highly coupled arrangement of the windings. When the machine is rotating, it therefore becomes possible to sequentially modulate the use of the sources without affecting the mechanical torque. For example, and in the case where the three voltages U Qi If the power outputs are equal, and a 50% / 25% / 25% distribution of the total power between the sources is desired, one fraction can be made active at all times, while the second and third fractions are deactivated 50% of the time. The deactivation timing of the fractions must be planned so that the thermal constraints are met for each fraction. This can be generalized to any number of highly coupled subdivisions. k B .

[0083] Regarding the fourth and final variant for power transfer between sources at the switching frequency, the duty cycles are calculated using conventional machine autopilot. Within a basic building block, the PWM signals associated with each of the m p phases are associated with intertwined carriers with a phase shift of 2 π / m p The systems m p Phased carriers are phase-shifted by a certain angle from one power converter to another. For example φ UV , is the control angle representing the angular delay of the system m p phased carriers of the elementary building block associated with a source V relative to the system m p phased carriers of the elementary building block associated with a U source. When φ UV >0, a power transfer from source V to source U at the switching frequency occurs. This transfer is independent of the machine's operating point and can therefore also occur with the rotor locked. When the converter of the basic building block consists of m p full-bridge inverters, the carriers of m p phases can be identical (phase shift of 2 π / m p is not necessary). Instead, it is sufficient to use a phase shift φ UV between the carriers of an elementary block associated with source U and those of an elementary block associated with source V to induce a power transfer between the two sources. This is generalizable for any number of highly coupled subdivisions. k B .

[0084] Typically at least one of the means of the device according to the invention previously described, preferably each of the means of the device according to the invention previously described, are technical means.

[0085] Typically, each of the means of the device according to the invention described above may include at least one computer, a central processing unit or computing unit, an analog electronic circuit (preferably dedicated), a digital electronic circuit (preferably dedicated), and / or a microprocessor (preferably dedicated), and / or software means.

[0086] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention.

[0087] Of course, the various features, forms, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described above are combinable.

Claims

1. Multi-source system comprising an electric machine (M), of the type comprising a rotor and a stator (1), the stator (1) comprising a plurality of windings (10,11,12) made of insulated conductive material, each winding (10,11,12) comprising a plurality of independently powered coils (100,101,102), the system also comprising a plurality of DC power sources (2) and a plurality of power electronics converters (3) associated with different coils (100,101,102) of the electric machine (M), each power source (2) powering one or more power electronics converters (3) and each power source (2) being connected to at least one coil (100,101,102) of each winding (10,11,12) of the electric machine (M), the coils (100,101,102) of the same winding (10, 11, 12) being supplied with signals of the same phase and the stator (1) comprising slots, characterised in that each slot comprises the coils (100, 101, 102) of the same winding (10, 11, 12) and in that the coils (100, 101, 102) of the same winding (10, 11, 12) are powered by separate power sources (2).

2. System according to claim 1, wherein the plurality of windings (10,11,12) is divided into at least two areas.

3. System according to claim 2, wherein the at least two areas correspond to electric machine sectors (S1, S2, S3).

4. System according to claim 2, wherein the at least two areas correspond to mp-phase electric machine systems.

5. System according to any one of claims 2 to 4, wherein the at least two areas are split, each fraction of each area being associated with a power electronics converter (3), the fraction and its power electronics converter (3) constituting an elementary electromechanical conversion unit.

6. System according to claim 5, wherein each elementary electromechanical conversion unit is associated with a power source (2).

7. System according to claim 4, wherein the mp-phase systems correspond to mp-phase electric machine systems temporally shifted by an electrical angle that is not a multiple of 60°.

8. System according to any one of the preceding claims, wherein the number of coils (100,101,102) in a winding is greater than or equal to the number of power sources.

9. System according to any one of the preceding claims, wherein the windings have a number of turns that is a multiple of the number of power sources (2).

10. Control method applied to a multi-source system according to any one of the preceding claims by at least one control circuit, the method comprising the following steps: - first distribution of the currents from the plurality of power sources (2) to at least one area of the electric machine, - second distribution of the currents to at least a fraction of each area.

11. Control method according to claim 10, wherein when each power source supplies a power electronics converter, the method comprises the following step: - direct distribution of the currents from the plurality of power sources (2) to at least one fraction of the electric machine.

12. Control method according to any one of claims 10 to 11, wherein the distribution of the currents of the plurality of power sources (2) to at least one fraction is balanced.

13. Control method according to any one of claims 10 to 12, wherein the method also comprises the following step: - introduction of an additional current component evolving at an arbitrary frequency.

14. Control method according to any one of claims 10 to 13, wherein the method also comprises a step of controlling the at least one fraction for activating and / or deactivating at least one fraction of the electric machine for a period of time T.

15. Control method according to any one of claims 10 to 14, wherein the distribution of currents from the plurality of power sources to at least one fraction is also carried out as a function of a switching frequency of one or more power electronics converters.