Electrical machine powered by multiple power sources and related methods

Abstract

The present invention relates to a multi-power source system comprising a rotor and an electric machine (M) having a stator (1). The stator (1) has a number of windings (10, 11, 12) made of insulated conductive material, each winding (10, 11, 12) having a number of independently powered coils (100, 101, 102). The system further comprises a number of DC power sources and a number of power electronic converters associated with different coils (100, 101, 102) of the electric machine (M), each power source feeding one or more power electronic converters, each power source connected to at least one coil (100, 101, 102) of each winding (10, 11, 12) of the electric machine (M).

Description

[Technical Field]

[0001] The present invention relates to a multi-electrical source system and a method for controlling such a system, which is relevant in fields such as the generation of on-board networks in aircraft, in the field of wind turbines or inertial storage associated with multiple networks. [Background technology]

[0002] In typical "multi-source" solutions, the power transfer between the sources is achieved by mechanical forces. However, this generates radial forces and torque ripple in the machine. In fact, these mechanical phenomena cause vibrations and reduce the lifespan of the machine elements. Furthermore, in these structures, the power transfer between the sources is limited by the intended torque / speed operating point. This transfer causes inhomogeneities in the induced magnetic field within the machine, resulting in additional losses. Summary of the Invention [Problem to be solved by the invention]

[0003] There are two categories of structures that allow energy to be exchanged between sources through mechanical force:

[0004] 1) The structure is subdivided into sectors based on the number of pole pairs in the machine. This is called a sectorized machine. This subdivision allows for multiple three-phase subsystems that are electrically independent and weakly magnetically coupled. This means that power transfer between different sources would unnecessarily increase the induction level in the machine and disturb the radial forces. The radial forces can be compensated for by adding current along the direct axis of the magnetic flux in the machine. All these factors mean that power transfer between three-phase subsystems in these structures is complex, introduces losses, and is only available over a small operating range.

[0005] 2) The so-called multi-phase structure is subdivided into several independent subsystems with a prime number of phases. Therefore, to allow the use of several power sources, the total number of phases is not a prime number. Usually, for industrial standardization, a solution employing several three-phase systems is used, which we refer to here as a "multiple three-phase machine." This subdivision results in several electrically independent and moderately magnetically coupled three-phase subsystems. Therefore, power transfer between different power sources causes inductive non-uniformities in the machine's magnetic circuit (and thus increases iron losses) and disturbs torque harmonics.

[0006] The object of the present invention is to overcome at least one of these drawbacks. [Means for solving the problem]

[0007] This object is achieved by a multi-power system including an electric machine consisting of a rotor and a stator, the stator including multiple windings made of insulated conductive material, each having multiple independently powered coils.

[0008] Under this premise, the system comprises a plurality of DC power sources, each corresponding to a different winding of the electric machine, and a plurality of power electronic converters associated with different coils of the electric machine, each power source supplying power to one or more power electronic converters, and each power source being connected to at least one coil of each winding of the electric machine.

[0009] The proposed invention allows for an improved use of electric machines in a multi-power supply environment by separating the power transfer between the power sources from the mechanical aspects. According to the invention, power is transferred mainly by electromagnetic phenomena and does not suffer from the mechanical obstacles mentioned above. The power transfer range is increased and the conversion efficiency is improved. The invention also allows for greater flexibility in the number of power sources interconnected via the electric machine.

[0010] This invention is equivalent to traditional designs in terms of manufacturing complexity, but it extends the achievable power transfer range, improves the efficiency of power transfer, and finally, allows the combination of more power sources than any other solution.

[0011] Coils of the same winding are supplied with signals of the same phase, and the stator has slots.

[0012] Each slot contains a coil of the same winding, and the coils of the same winding are powered by separate power supplies.

[0013] Windings according to the present invention may be "distributed" or "toothed / concentric" or "finely divided pitch" depending on the embodiment.

[0014] The plurality of windings may be divided into at least two regions.

[0015] The at least two regions may correspond to sectors of the electric machine. The at least two regions may correspond to an mp-phase electric machine system. "Sector" means a region of the electric machine corresponding to at least one pair of magnetic poles of a stator.

[0016] At least two regions are divided, and each region has a detail associated with a power converter, the detail and the power converter constituting an elementary electromechanical conversion unit.

[0017] Each elementary electromechanical transduction unit may be associated with a power source.

[0018] In general, in a general-purpose machine with m phases, if there are p pairs of stator poles with Ns windings per pole and per phase, then p × k B It is possible to use k electromagnetic conversion units (grouping of inverters and details), where k B is an integer divisor of Ns. If m is not a prime number, that is, m = n × mp, it is also possible to divide the m phases into n mp phase systems. This gives a total of p × n × k BThe element unit of the electromagnetic conversion unit may include a prime number mp.

[0019] In most cases, this prime number is mp=3.

[0020] The elemental electromechanical converter unit comprises a coil of an mp-phase system associated with a unique static power electronic converter (inverter). This converter is associated with one of the DC power sources of the system and provides a voltage U DC,i There are two ways to arrange these mp coils and transducers.

[0021] First, the converter has mp inverter arms, each associated with a coil. The coils have a common potential called the "neutral." This neutral imposes a zero-sequence current on the structure.

[0022] In the second configuration, the converter has mp full inverter bridges, each associated with a coil. Because there is no neutral, twice as many switches are required to control the zero-sequence component. This component does not affect torque, but can be used to transfer power between sources.

[0023] The present invention proposes a fine division of the windings, making it possible to separate the problem of mechanical force (torque harmonics or radial forces) distribution from the problem of energy transfer between the sources. For this purpose, this multi-source structure is BThe electrical machine comprises power sources, each supplying p×n converters, with all converters associated with each power source connected to a coil (singular) in each winding of the electrical machine. Control of torque harmonics and radial forces is important in certain applications (such as low torque ripple or "bearingless" applications). Therefore, to maintain these means of operation / control, the present invention proposes a combination of a finer division of the winding into multiple coils and a subdivision into regions such as sectors or polyphase systems, prioritizing the control structure to maintain decoupling of energy transfer from mechanical forces.

[0024] An mp-phase system may correspond to an mp-phase electromechanical system with a time lag whose electrical angle is not a multiple of 60°. This corresponds to a multi-phase structure in which the number of electrically distinct phases is a multiple of three.

[0025] The number of coils in a winding must be equal to or greater than the number of power sources. For example, if a system has two power sources, the number of coils in the same winding must be equal to or greater than two. For three power sources, the number of coils in the same winding must be equal to or greater than three.

[0026] The windings may have a number of turns proportional to the number of power sources. For example, if a system has two power sources, the number of turns in each winding corresponds to a multiple of two. If there are three power sources, the number of turns in each winding corresponds to a multiple of three.

[0027] According to another aspect of the present invention, there is proposed a control method applied to the multiple power supply system of the present invention by at least one control circuit, the method comprising the following steps:

[0028] a first distribution that distributes current from the plurality of power sources to at least one region of the electric machine;

[0029] - A second distribution that distributes the current to at least one detail in each region.

[0030] The two steps of the method are independent of each other.

[0031] The distribution of current to each region of an electric machine is used to determine the mechanical state (torque and force). The distribution of current to each detail of each region is used to determine the power transfer between sources.

[0032] Current can be distributed to each region depending on the radial force or torque harmonic requirements. It is also possible to use current distribution to each region depending on the need for energy exchange between different power sources. The main applications where radial force needs to be kept under control are when it is desirable to damp the forces acting on mechanical bearings or when it is necessary to ensure full magnetic levitation of the rotor. Radial forces are exerted on the rotor from the stator and its conductors to magnetically center the rotor or simply to limit the radial force that the rotor exerts on its bearings.

[0033] In a multi-power architecture, it is necessary to manage the power drawn from each power source, and more generally to manage the power exchange between the different power sources, ensuring their balance and other functions required for energy monitoring. The overall energy management of the system is carried out through the machine.

[0034] The distribution of at least one current to each detail of each region may be performed according to the energy exchange requirements between the different power sources, thereby balancing the power sources and, more generally, controlling the energy supplied or consumed by them.

[0035] If each power source supplies power to a power electronic converter, the method may include the following steps.

[0036] - Direct distribution of current from several power sources to at least one detail of the electric machine.

[0037] The distribution of current from the multiple power sources to at least one branch may be balanced.

[0038] In this embodiment, each power source supplies power to a single power converter.

[0039] The present invention employs an arrangement of the different element windings that maximizes the magnetic coupling of the windings. The power transfer between the different power sources is done electromagnetically, reducing the mechanical impact on the rotor. The two functions of torque generation and power transfer between the power sources are nearly independent in design. As a result, torque generation and radial force are independent of the power transfer between the power sources. The level of induction in the magnetic circuit depends only on the torque operating point and therefore does not depend on the power transfer between the power sources. Our solution therefore reduces iron losses on the machine side. Power transferability is improved near base speed.

[0040] The method may include the following steps.

[0041] - introduction of an additional current component that varies with arbitrary frequency.

[0042] The power transfer can occur at any frequency, which allows the power transfer to be decoupled from the mechanical operating point. In particular, it allows power to be transferred between sources even when the rotor is locked, since standard self-regulation generates a continuous value at standstill that is incompatible with electromagnetic power transfer.

[0043] The method may also comprise the step of controlling at least one detail of the electric machine to activate and / or deactivate the at least one detail for a period of time T.

[0044] The distribution of current from the multiple power sources to the at least one detail may also be performed as a function of the switching frequency of one or more power electronic converters.

[0045] Other advantages and features of the present invention will become apparent on reading the detailed description of non-limiting embodiments and examples, as well as the accompanying drawings, which follow. [Brief explanation of the drawings]

[0046] [Figure 1] a) shows a three-phase version of the electric machine according to the invention, and b) shows an enlarged view of the electric machine shown in FIG. 1a. [Figure 2a] 1 shows a first embodiment of a multiple power supply system with radial force control. [Figure 2b] 1 shows a multi-power supply system with radial force control according to a second embodiment. [Figure 3] The control method is shown applied to the multi-power supply system shown in FIG. 2b. [Figure 4a] 1 shows a multiple power supply system with torque ripple control according to a first embodiment. [Figure 4b] 1 shows a multi-power supply system with torque ripple control according to a second embodiment. [Figure 5] A control method applied to the multi-power supply system shown in FIG. 4b is shown. [Figure 6] 1 shows a multi-power system with torque ripple and radial force control. [Figure 7] A control method applied to the multiple power supply system shown in FIG. 6 is shown. [Figure 8] 10 illustrates a control method applied to a multiple power supply system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0047] These embodiments are not intended to be limiting in any way, and in particular, variations on the invention may be contemplated in which any of the features described or shown below are selected in isolation from other features (even if this selection is isolated within a context that includes other features), provided that this selection of features confers a technical advantage or is sufficient to distinguish the invention from the prior art. This selection includes at least one feature, preferably a functional feature without structural details, and / or only a portion of structural details, provided that this portion alone is sufficient to confer a technical advantage or distinguish the invention from the prior art.

[0048] In the following description, the term "electric machine" refers to both the actual electric machine that converts electrical energy into mechanical energy (motor) and the inverse function (generator). The principles of the present invention are applicable to all types of electric machines, e.g., synchronous, asynchronous, and variable resistance machines. The type of electric machine is determined by the type of rotor used.

[0049] In general, a general-purpose motor can be thought of as having m phases, with p pairs of stator poles per phase, and Ns windings per pole and per phase. If m is not a prime number, that is, m = n × mp, it is also possible to divide the m phases into n mp-phase systems. Within each slot, k windings are B This structure allows the energy management to be separated from the generation of the radial forces, while ensuring that the magnetic circuit of the machine is used uniformly during the energy exchange.

[0050] FIG. 1a shows an electric machine according to the present invention. FIG. 1b shows an enlarged view of the electric machine shown in FIG. 1a. The electric machine consists of a rotor (not shown) and a stator 1 consisting of windings in slots 10, 11, 12, where the three windings in slots 10, 11, 12 belong to the same phase A+. The windings 10, 11, 12 are divided into several coils 100, 101, 102, 110, 111, 112, and 120, 121, 122. Each coil 100, 101, 102 of, for example, the same winding 10, has its own terminal through which power is supplied.

[0051] In the embodiment of Figures 1a) and 1b), each winding 10, 11, 12 is divided into three coils 100, 101, 102, 110, 111, 112, and 120, 121, 122. Each phase A+ / -, B+ / -, C+ / - is k B divided into k magnetically coupled subphases (field lines emanating from coils of the same winding point in the same direction), BThe electrical submachines are divided into four submachines (Fig. 1a), each consisting of coils [102, 112, 122], [101, 111, 121], and [100, 110, 120]. This division means that the blocks of windings are arranged in parallel rather than in series, which allows for separate supply signals with lower voltages. The coils of the same winding are therefore mechanically (but not electrically) parallel within the same winding. Since they are supplied with signals of the same phase, the ampere-turns they generate are additive. In the examples shown in Figs. 1a) and 1b), the coils of the same winding are arranged one after the other, but the coils may also be intertwined, mixed, or overlapped without adversely affecting the invention.

[0052] In other words, signals of the same phase are supplied to the coils 100, 101, 102 of the same windings 10, 11, 12. The stator 1 has slots a, b, c, a', b', c', and a", b", c". Furthermore, each slot is provided with the coils 100, 101, 102 of the same windings 10, 11, 12. Furthermore, power is supplied to the coils 100, 101, 102 of the same windings 10, 11, 12 from separate power sources 2.

[0053] An embodiment of the slots is shown in Figures 1a, 1b, 2a, 2b, 4a, 4b, and 6. Each slot may include at least two coils of the same winding. For example, each slot may include three coils 100, 101, and 102 of the same winding 10, 11, and 12. The slots form a housing for accommodating multiple coils. Each slot extends longitudinally along a radially referenced axis associated with the slot. Each radial axis is oriented toward the center of the machine, i.e., the center of the rotor. The radial axis extends along the radius of the machine rotor and passes through the slot with which it is associated.

[0054] Typically, coils of the same winding within the same slot are sequentially arranged, intertwined, interlaced, or overlapped. For example, as shown in Figure 1b, coils of the same winding are overlapped within the same slot. This means that coils of the same winding housed within the same slot are radially aligned along the radial axis associated with the slot.

[0055] For example, slots a, b, c (preferably each slot) are associated with phases A+ / -, B+ / -, and C+ / -, respectively. Furthermore, each slot a, b, and c is associated with a winding 10, 11, and 12, respectively. Furthermore, each coil of the same winding has two terminals, a first terminal and a second terminal, for supplying power to the coil. For example, each coil of the same winding has a first terminal arranged in a first portion A+, B+, and C+ of the housing formed by slots a, b, and c, and a second terminal arranged in a second portion A-, B-, and C- of the housing formed by slots a, b, and c.

[0056] Figures 1a and 1b show exactly what an electric machine is with a 9-phase stator, i.e., m = n × m = 9 (m = 3), with each phase having three pairs of poles (p = 3). The stator has 18 slots for each pole pair, for a total of 54 slots. Thus, in a standard three-phase configuration, each phase is distributed over three consecutive slots. Each slot contains three coils or conductors, or groups of conductors (k B =3). Each coil or conductor is associated with one of the rows, row 1, row 2, or row 3. Row 1 is characterized by being closest to the rotor (the center of the electric machine). Therefore, the electric machine of interest has n=p=k B = 3. The "+" conductor enters the stator and the "-" conductor exits the stator.

[0057] An electric machine may be connected to multiple power sources, each connected to multiple power converters. The DC power source supplying each power converter has a voltage U Q,iEach converter is provided with a control circuit. The electric machines are used as a reference to illustrate different embodiments of the invention. However, the electric machines shown in Figures 1a) and 1b) do not limit the invention to this application. This is for illustrative purposes. In other embodiments, B may be equal to 2, for example (see Figures 2a and 4a).

[0058] 2a and 2b show a multi-power system with radial force control without coordination between the energy management and radial force management functions.

[0059] k B A structure is considered in which p energy sources are associated with an electric machine. Each energy source feeds p transducers, each associated with a different pole pair in the machine. These different pole pairs are represented in the diagram below by different shades of grey and are separated by dotted lines.

[0060] The electric machine shown in Figures 2a and 2b is divided into three regions or sectors (S1, S2, S3) corresponding to the three pairs of poles of the machine. As shown in Figure 2a, the multi-power system includes an electric machine M configured as described above, multiple power sources 2, and multiple power converters 3. The electric machine M is connected to two power sources 2, U and V. Each power source 2 is associated with three power converters 3. As a result, a total of six power converters 3 are used. Here, two power sources 2 are used, k B =2. For each power supply 2, the first converter 3 is associated with phases A1+ / -, B1+ / -, C1+ / -, representing the first pair of stator poles (area S1). The second converter is associated with phases A2+ / -, B2+ / -, C2+ / -, representing the second pair of stator poles (area S2). The third converter is associated with phases A3+ / -, B3+ / -, C3+ / -, representing the third pair of stator poles (area S3). Power supply U supplies power to the coils in row 1 of each area, and power supply V supplies power to the coils in row 2 of each area.

[0061] According to Fig. 2b, based on the same principle as Fig. 2a, a multi-power system comprises the electric machine M described above, multiple power sources 2, and multiple power converters 3. The electric machine M is connected to three power sources 2, U, V, and W. Each power source 2 is associated with three power converters 3. As a result, a total of nine power converters 3 are used. Here, k B Since π = 3, three power supplies 2 are used. For each power supply 2, a first converter 3 is associated with phases A1, B1, and C1, representing the first pair of stator poles (area S1). A second converter 3 is associated with phases A2, B2, and C2, representing the second pair of stator poles (area S2). A third converter 3 is associated with phases A3, B3, and C3, representing the third pair of stator poles (area S3). Power supply U supplies the coils in row 1 of each area, power supply V supplies the coils in row 2 of each area, and power supply W supplies the coils in row 3 of each area. In other embodiments, rows and areas can be mixed for the same power supply. For example, row 1 of area 1, row 2 of area 2, and row 3 of area 3 may be associated with the same power supply.

[0062] With reference to Figure 3, a control method to be applied to the multi-power supply system shown in Figure 2b will now be described. The control method of the present invention is applied by a respective control circuit for each converter 3 of the system. In another embodiment, the method may also be applied, for example, by a common control circuit for all converters 3. The method comprises the following steps:

[0063] - A first distribution that distributes current from the multiple power sources to at least one region of the electric machine.

[0064] - A second distribution in which the current is distributed to at least one detail of each area.

[0065] The two steps of the method are independent of each other, regardless of the embodiment. The winding of the electric machine is divided into three regions, which correspond to sectors S1, S2, and S3, as shown by the dotted lines in Figure 2b. Sectors S1, S2, and S3 correspond to clearly defined regions of the electric machine M. Sector S1 has phases A1+ / -, B1+ / -, and C1+ / -. Sector S2 has phases A2+ / -, B2+ / -, and C2+ / -. Sector S3 has phases A3+ / -, B3+ / -, and C3+ / -.

[0066] Sectors S1, S2, and S3 are further divided. Each detail is associated with at least one phase of the electric machine. Here, the details are grouped together: 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 applies similarly to the multiple-source system shown in FIG. 2a, only the number of sources is different.

[0067] As shown in Figure 3, the reference current I is set as a function of speed based on the torque and flux operating point to be reached. dq are expressed in the Park reference frame and correspond to the currents observed in a reference electric machine (see Figures 1a and 1b). Based on the requirements for the applied radial force, these currents are xy1 , K. xy2 , K. xy3 Depending on the function of I, each sector S1, S2, S3 dq1 , I dq2 , I dq3 These currents I dq1 , I dq2 , I dq3 is the energy exchange demand K between power sources U, V, and W pu , K. pv , K. pw According to the above, each sector S1, S2, S3 is divided into three sub-sectors (1u, 1v, 1w), (2u, 2v, 2w), (3u, 3v, 3w).

[0068] For example, three voltages U Qiare equal, sector S3 must work harder than the other two sectors to generate the radial force that pulls the rotor to the right. Therefore, a 25% / 25% / 50% total power distribution among the three sectors can be adopted. Furthermore, if there is an energy management requirement that power source U is used the most, a 50% / 25% / 25% total power distribution among the sources can be adopted.

[0069] Therefore, of the 25% allocated to sector S1, 12.5% ​​goes to row 1 and 6.25% goes to rows 2 and 3 (12.5+2*6.25=25). Of the 25% allocated to sector S2, 12.5% ​​goes to row 1 and 6.25% goes to rows 2 and 3 (12.5+2*6.25=25). Of the 50% allocated to sector S3, 25% goes to row 1 and 12.25% goes to rows 2 and 3 (25+2*12.5=50). K xy1 , K. xy2 , K. xy3 corresponds to the percentage associated with each sector S1, S2, S3. pu , K. pv , K. pw corresponds to the percentage of total power allocated to each power source U, V, W.

[0070] Starting from the electrical machine M, the degrees of freedom k B Interconnecting the sources with and p ensures that the energy transfer between the sources does not affect the radial forces in the machine. Using p=3 power converters for each source maintains degrees of freedom for active radial force control.

[0071] In either Figure 2a or Figure 2b, each power source is ultimately associated with a winding located around the periphery of the machine, which makes it possible to manage the use of different power sources without generating radial forces on the rotor. However, with proper control prioritization, it is still possible to utilize the structural freedom to generate radial forces and achieve magnetic centering without imbalance between the power sources. First, it is necessary to define the force contribution of each sector (or pole pair), and then manage the distribution of power source usage so that it is the same for all sectors. This method is applicable regardless of the machine characteristics (n, p). The number of slot subdivisions k B may be equal to or greater than the number of power sources.

[0072] Figure 4a shows a multi-source system with torque ripple control according to a first embodiment. The electric machine shown in Figures 4a and 4b is divided into three regions, i.e., three-phase systems, according to the same principle as in Figures 2a and 2b. These three three-phase systems correspond to the three pole pairs of the machine.

[0073] As shown in FIG. 4a, an electric machine M is connected to two power sources 2, U and V. Each power source 2 is associated with three power converters 3. Each converter is associated with a region of the electric machine corresponding to a different mp-phase system. These different mp-phase systems are offset by an electrical angle equal to 20 degrees. In this embodiment, the angle is 20 degrees because the example has 18 slots per pole pair (360 / 18=20). The mp-phase system associated with the first converter of each power source is associated with slot a of phase A+ / -, slot b of phase B+ / -, and slot c of phase C+ / -, i.e., the first slot of each phase. For the second converter of each power source, the mp-phase system is associated with the second notch a', b', c' of the referenced phase. For the third converter of each power supply, the mp-phase system is associated with the third and last slot a", b", c" of the referenced phase. Power supply U supplies the coils in row 1 of each region, and power supply V supplies the coils in row 2 of each region. In other embodiments, it is possible to mix rows and regions for the same power supply. For example, row 1 of region 1 and row 2 of region 2 are associated with the same power supply.

[0074] Figure 4b shows a multi-source system with torque ripple control, where there is no coordination between the "energy management" and "torque ripple" management functions. B A structure is considered that associates n energy sources with an electric machine. Each source supplies n converters, each assigned to a region corresponding to a different mp phase system of the electric machine. These different mp phase systems are offset by a certain electrical angle and are shown in different shades in the diagram below. This offset is indicated by the dashed line at the pole of phase A.

[0075] According to FIG. 4b, based on the same principle as in FIG. 4a, an electric machine M is connected to three power sources 2 (U, V, W). Each power source 2 is connected to three power converters 3. Each converter is connected to a separate mp-phase system. These different mp-phase systems are offset by an electrical angle of 20 degrees. The reason for the 20-degree angle in this embodiment is that the example has 18 slots per pole pair (360 / 18=20). The mp-phase system associated with the first converter of each power source is associated with slot a of phase A+ / -, slot b of phase B+ / -, and slot c of phase C+ / -, i.e., with the first slot of each referenced phase. The second converter of each power source is associated with the second notch a', b', c' of the referenced phase. The third converter of each power supply is associated with the third and final slot a", b", c" of the referenced phase. Power supply U supplies the coils in row 1 of each region, power supply V supplies the coils in row 2 of each region, and power supply W supplies the coils in row 3 of each region. In other embodiments, rows and regions can be mixed for the same power supply, for example, row 1 of region 1, row 2 of region 2, and row 3 of region 3 are associated with the same power supply.

[0076] With reference to Figure 5, a control method to be applied to the multi-power supply system shown in Figure 4b will now be described. 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 is applied, for example, by a control circuit common to all converters 3. As mentioned above, the method comprises the following steps:

[0077] - A first distribution for distributing current from a plurality of power sources to at least one region of the electric machine.

[0078] - a second distribution of the current to at least one detail in each region. The windings of the electric machine M are divided into three regions corresponding to three-phase or mp-phase systems, each three-phase system being associated with a converter 3.

[0079] The three-phase system associated with each converter is further divided. Each detail corresponds to a separate coil of the winding that makes up the three-phase system of the electric machine. Here, for each power source, the first converter supplies the detail of the area corresponding to slots a, b, and c, the second converter supplies the detail of the area corresponding to slots a', b', and c', and the third converter supplies the detail of the area corresponding to slots a", b", and c". Based on the torque and flux operating point to be reached, i.e., speed, the applied reference current I dq are expressed in the Park reference frame, and they correspond to the currents observed in the referenced electric machine (Figure 1a, Figure 1b). To minimize torque ripple, these currents I dq is a function of Kh, K′h, K″h, I dq , l' dq , and l” dq Then, the current I dq , I' dq , and l” dq is the energy exchange demand K between power sources U, V, and W pu , K. pv , and K. pw Each three-phase system is further divided into three subdivisions (u, v, w), (u′, v′, w′), and (u″, v″, w″) according to a function of . Advantageously, the three mp-phase systems should operate equally, i.e., in a balanced manner, to minimize the fluctuations in the torque acting on the rotor in the healthy mode. For example, the three voltages U Qi are equal, the allocation is 33% / 33% / 33% of the total power of the three mp-phase systems. Then, if energy management requirements dictate that source U is the most used, a 50% / 25% / 25% allocation of the total power among the sources can be adopted. Thus, of the 33% allocated to the first mp-phase system, 16.7% is allocated to row 1, and 8.4% each to rows 2 and 3 (16.7 + 2 x 8.4 = 33). A similar rule applies to the other two regions. Starting with the electric machine M, and the k degrees of freedom, Band n to interconnect the sources so that the energy transfer between the sources does not affect the torque ripple of the machine. By using n=3 power converters for each source, the freedom of active torque ripple control is maintained.

[0080] In either Figure 4a or Figure 4b, the converter associated with each source ultimately supplies the windings corresponding to the area corresponding to the mp-phase system. This allows managing the use of the different sources without compromising the torque harmonics. This is achieved by setting appropriate control priorities. First, it is necessary to define the harmonized control between the different mp-phase systems, and then manage the distribution of source use common to all mp-phase systems. This method is very flexible depending on the machine characteristics (n,p) and the number of slot subdivisions k. B It is applicable regardless of k B is preferably equal to or greater than the number of power sources. B is preferably equal to the number of power supplies in the system. The control method described above is equally applicable to the multiple power supply system shown in Figure 4a.

[0081] A multi-source system with torque ripple and radial force control, with no coordination between the energy management and mechanical force management functions, is described with reference to Figure 6. The electric machine shown in Figure 6 is divided into three regions or sectors (S1, S2, S3) corresponding to the three pole pairs of the machine.

[0082] The electric machine M is connected to three power sources 2, U, V, and W. Each power source 2 is associated with three power converters 3. For each power source 2, a first converter 3 is associated with phases A1, B1, and C1, representing the first pair of stator poles (area S1). A second converter 3 is associated with phases A2, B2, and C2, representing the second pair of stator poles (area S2). A third converter 3 is associated with phases A3, B3, and C3, representing the third pair of stator poles (area S3). These pole pairs are associated with a three-phase system offset by an electrical angle equal to 20 degrees. The angle is 20 degrees in this embodiment because the example has 18 slots per pole pair (360 / 18=20). Power supply U supplies the coils in row 1 of each region, power supply V supplies the coils in row 2 of each region, and power supply W supplies the coils in row 3 of each region. In other embodiments, it is possible to mix rows and regions with the same power supply. For example, row 1 of region 1, row 2 of region 2, and row 3 of region 3 are associated with the same power supply.

[0083] With reference to Figure 7, a control method applied to the multi-power supply system shown in Figure 6 will now be described. The control method of the present invention is applied by a respective control circuit for each converter 3 of the system. In another embodiment, it may be applied, for example, by a common control circuit for all converters 3. As mentioned above, the method comprises the following steps:

[0084] - a first distribution for distributing current from the plurality of power sources to at least one region of the electric machine;

[0085] - a second distribution for distributing the current to at least one detail of each region.

[0086] The windings of the electric machine M are divided into three regions corresponding to sectors S1, S2, and S3, as shown by the dotted lines in FIG. 6 . Sectors S1, S2, and S3 correspond to clearly defined regions of the electric machine M. Sector S1 has phases A1+ / -, B1+ / -, and C1+ / -. Sector S2 has phases A2+ / -, B2+ / -, and C2+ / -. Sector S3 has phases A3+ / -, B3+ / -, and C3+ / -. In this example, the phases of the three sectors defined by the dotted lines are offset by an electrical angle equal to 20 degrees (see the description of the embodiment in the previous figure).

[0087] The areas corresponding to sectors S1, S2, and S3 are further divided. Each detail corresponds to a phase of the electric machine. Here, the details are grouped together, 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. Based on the torque and flux operating point to be reached, the reference current I applied is dq are expressed in the Park reference frame and correspond to the currents observed in the reference electric machine (Figure 1a, Figure 1b). To minimize torque ripple and apply the desired radial force, these currents I dq is K xy1 , K. xy2 , and Kxy3 Depending on the function of dq1 , I dq2 , I dq3 The current I dq1 , I dq2 , I dq3 is the energy exchange demand K between power sources U, V, and W pu , K. pv , and K. pw Each three-phase system is further divided into three parts (1u, 1v, 1w), (2u, 2v, 2w), (3u, 3v, 3w) according to the function of QiIf the d-axis currents are equal, sector S3 must work harder than the other two on the d-axis of the Park coordinate system to exert a radial force on the rotor pulling it to the right. Therefore, a 25% / 25% / 50% distribution of d-axis currents can be adopted for the three sectors. For the q-axis, a fair distribution must be maintained to ensure minimal torque ripple. Therefore, a 33% / 33% / 33% distribution of q-axis currents can be adopted for the three sectors. Next, if the energy management requirement is that power supply U is the most utilized, a 50% / 25% / 25% distribution of total power between the power supplies can be adopted. Therefore, of the 25% allocated to sector S1 based on the d-axis current, 12.5% ​​is allocated to row 1 and 6.25% is allocated to rows 2 and 3 (12.5 + 2 × 6.25 = 25). Of the 33% allocated to sector S1 for the q-axis current, 16.7% is allocated to row 1 and 8.4% to rows 2 and 3 (16.7 + 2 × 8.4 = 33). Therefore, of the 25% allocated to sector S2 based on the d-axis current, 12.5% ​​is allocated to row 1 and 6.25% to rows 2 and 3 (12.5 + 2 × 6.25 = 25). Of the 33% allocated to sector S2 for the q-axis current, 16.7% is allocated to row 1 and 8.4% to rows 2 and 3 (16.7 + 2 × 8.4 = 33). Of the 50% allocated to sector S3 based on the d-axis current, 25% is allocated to row 1 and 12.25% each to rows 2 and 3 (25 + 2 × 12.5 = 50). Of the 33% allocated to sector S3 for the q-axis current, 16.7% is allocated to row 1 and 8.4% to rows 2 and 3 (16.7 + 2 × 8.4 = 33).

[0088] Starting from the three-phase machine M, the degrees of freedom k B , n, p to interconnect the sources so that the energy transfer between the sources does not affect the torque ripple of the machine. By using n=p=3 power converters for each source, the degrees of freedom for active torque harmonics and radial force control can be maintained.

[0089] As shown in FIG. 8, the method of the present invention is also applicable to systems with multiple power sources 2. Each power source 2 is connected to a single converter 3. In practice, such a system may comprise, for example, an electric machine M as shown in FIG. 1, and multiple power sources 2, each connected to a single power converter 3. The electric machine M is connected to three power sources 2: U, V, and W. For each power source 2, the converter 3 is associated with pole pairs of phases A+ / -, B+ / -, and C+ / -. Power source U supplies the pole pairs in row 1, power source V supplies the pole pairs in row 2, and power source W supplies the pole pairs in row 3. In other embodiments, it is possible to mix rows and regions for the same power source. For example, row 1 in region 1 and row 2 in region 2 are associated with the same power source.

[0090] The control method applied in this particular multi-power supply system is applied by a respective control circuit of each converter 3. In another embodiment, the method may be applied by a common control circuit for all converters 3, for example. The method comprises the following steps:

[0091] - Direct distribution, which distributes current from multiple sources to at least one detail of an electric machine.

[0092] In this embodiment, the electric machine is directly divided: each detail is associated with a phase of the electric machine, where the details correspond to the windings of phases A, B, C.

[0093] Based on the torque and flux operating point to be reached, the reference current I is applied. dq are expressed in the Park reference frame and correspond to the currents observed in the reference electric machine (Figures 1a and 1b). These currents I dq is the energy exchange demand K between power sources U, V, and W pu , K. pv , K. pw Depending on dq *K pu , I dq *K pv , I dq *K pwIt will be distributed among three subdivisions: uv and P vw are the powers exchanged between power source U and power source V, and between power source V and power source W, respectively.

[0094] The invention also concerns four variants of the control method applicable to the above structure. These variants are applied depending on the result to be achieved. These variants are only concerned with the subdivision step of the electric machine, i.e. the distribution of the current to each detail in each area. These variants are also applicable when the machine is not subdivided into areas, but is only divided into rows in the slots. This distribution allows the power transfer between the sources.

[0095] - based on the rotation frequency of the magnetic field generated by the rotor of the machine,

[0096] - or based on any frequency via PWM control of the inverter,

[0097] - or based on sequential activation / deactivation of subdivisions,

[0098] - Or based on the inverter switching frequency by adjusting the phase shift of the PWM carrier.

[0099] Variations of the control method may be applied to electric machines with multiple details in the same stator slot (distributed windings) or multiple details around the teeth of the same stator slot (concentrated windings). Variations of the control method may be applied to structures with at least two details in a slot. Such variations relate to interactions between highly coupled subdivisions. They are used to control power converters associated with separate power sources whose windings share the same slot.

[0100] The first variants to decouple the power transfer between the mutual power sources and the management of radial forces (structural features) were introduced early on through the distribution of power directed to each area. For example, three voltage U Qi If , , and , are equal, the requirement for energy management for the most used power source U may lead to a 50% / 25% / 25% distribution of the total power among the power sources. Thus, in each region, 50% of the power is directed to row 1, 25% to row 2, and 25% to row 3. This first variant will be used throughout the description of the embodiment. This can be achieved by using any number of highly connected subdivisions k B It is possible to generalize to

[0101] In the second variant for power transfer between sources at any frequency, self-regulation allows k B The average duty cycle of the PWM applied to the power converters can be set based on the electrical angle. This angle can be measured using a position sensor or obtained by an estimator, which allows for "sensorless" control. The three voltages U Qi If the torque contributions of each detail are equal, then the torque contributions of each detail are balanced at 33% / 33% / 33%. In this way, an initial duty cycle value is assigned that controls the fair distribution of current in each detail. To transfer energy between the different subdivisions, an additional current component is introduced that occurs at an arbitrary frequency. This arbitrary frequency cannot be equal to the electrical frequency that links the rotation of the electric machine M. This allows for the creation of a torque distribution across any number of highly coupled subdivisions k. B It can be generalized to

[0102] In the third variant of the control method for sequential power usage management based on conventional machine control, k B Instead of >1, only one conventional machine control is implemented. This allows k BThe same three-phase PWM signal is distributed to the three power converters, each with its own control circuit. The only degree of freedom used to manage the different power converters is the "enable" signal associated with the control circuit of the different power converters, which controls whether the power converter is set to a "high impedance" state or not. This simplicity is achieved by the highly coupled winding arrangement. When the machine is rotating, it is possible to adjust the power usage sequentially without affecting the mechanical torque. For example, three voltages U Qi If a 50% / 25% / 25% distribution of total power is desired between the power sources, then the first detail can be kept active at all times, while the second and third details can be ensured to be deactivated 50% of the time. The timescales for disabling the details must be planned to satisfy the thermal constraints of each detail. This can be achieved with any number of highly coupled subdivisions k B It can be generalized to

[0103] In the fourth and final variant of power transfer between power sources at switching frequencies, the duty cycle is calculated from the classical mechanical self-control. Within each element, the PWM signals associated with each mp phase are associated with an interleaved carrier with a phase shift of 2π / mp. The mp-phase carrier system is phase shifted by a specific control angle from one power converter to another. For example, φ uv is a control angle representing the angular delay between the element-by-element mp-phase carrier system associated with power source V and the element-by-element mp-phase carrier system associated with power source U. φ uv >0, power is transferred from source V to source U at the switching frequency. This transfer is independent of the machine's operating point and can therefore be performed even when the rotor is locked. If the element-wise converter consists of an mp full-bridge inverter, the mp-phase carriers may be identical (the 2π / mp phase shift is not required), but there is a phase shift φ between the element-wise carrier associated with source U and the element-wise carrier associated with source V. uvis sufficient to induce power transfer between two sources. This can be achieved by using any number of highly coupled subdivisions k B It can be generalized to

[0104] Typically, at least one of the means of the device according to the invention described above, preferably each of the means of the device according to the invention described above, is a technical means.

[0105] Typically, each of the means of the device according to the invention described above may comprise at least one computer, central processing or computing unit, analog electronic circuitry (preferably dedicated), digital electronic circuitry (preferably dedicated), and / or microprocessor (preferably dedicated), and / or software means.

[0106] Naturally, the invention is not limited to the examples described so far, and many modifications can be made to these examples without departing from the scope of the invention.

[0107] Naturally, the various features, forms, modifications, and embodiments of the present invention may be associated with one another in various combinations, to the extent that they are not mutually exclusive or inconsistent with one another. In particular, all modifications and embodiments described above may be combined with one another.

Claims

1. A system comprising an electric machine (M) having a rotor and a stator (1), said stator (1) having a plurality of windings (10, 11, 12) made of an insulated conductive material, each of said windings (10, 11, 12) having a plurality of independently powered coils (100, 101, 102), Furthermore, the electric machine (M) comprises a plurality of DC power sources (2) and a plurality of power electronic converters (3) associated with different coils (100, 101, 102) of the electric machine (M), Each power source (2) drives one or more power electronic converters (3), each power source (2) being connected to at least one coil (100, 101, 102) of each winding (10, 11, 12) of said electric machine (M); In a system in which the coils (100, 101, 102) belonging to the same winding (10, 11, 12) are supplied with signals of the same phase and the stator (1) has slots, 1. A multi-power supply system, characterized in that each slot has said coils (100, 101, 102) of the same winding (10, 11, 12), and said coils (100, 101, 102) of the same winding (10, 11, 12) are powered by separate power supplies (2).

2. 2. The system of claim 1, wherein the plurality of windings (10, 11, 12) are divided into at least two regions.

3. The system of claim 2 , wherein the at least two regions correspond to electromechanical sectors (S1, S2, S3).

4. The system of claim 2 , wherein the at least two regions correspond to an mp-phase electromechanical system.

5. 5. A system according to claim 2, wherein the at least two regions are divided into sub-regions, each sub-region being associated with a power electronic converter (3), said sub-region and its power electronic converter (3) constituting an elementary electromechanical conversion unit.

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

7. The system of claim 4 , wherein the mp-phase system corresponds to an mp-phase electromechanical system shifted in time by an electrical angle that is not a multiple of 60°.

8. 8. The system according to any one of claims 1 to 7, wherein the number of coils (100, 101, 102) in the winding is equal to or greater than the number of power sources.

9. 9. The system according to claim 1, wherein the winding has a number of turns that is a multiple of the number of power sources (2).

10. A control method applied by at least one control circuit to the multiple power supply system according to any one of claims 1 to 9, comprising: a first distribution step of distributing the current from said plurality of power sources (2) to at least one region of said electric machine; a second distribution step of distributing said current to at least one detail of each region.

11. If each power source supplies power to a power electronic converter, A control method according to claim 10, comprising a step of direct distribution of the current from said plurality of power sources (2) to at least one detail of said electric machine.

12. 12. Control method according to claim 10 or 11, wherein the distribution of the currents of the power sources (2) to at least one detail is balanced.

13. A control method according to any one of claims 10 to 12, further comprising the step of introducing an additional current component which varies with an arbitrary frequency.

14. 14. The control method according to any one of claims 10 to 13, further comprising the step of controlling said at least one detail of said electric machine so as to activate and / or deactivate said at least one detail during a time T.

15. 15. A control method according to any one of claims 10 to 14, wherein the allocation of current from the plurality of power sources to the at least one detail is performed as a function of the switching frequency of one or more power electronic converters.

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