Switched mode power converter configured to control at least one phase of a polyphase electrical receiver with at least three phases

Abstract

A switched-mode power converter configured to control at least one phase of a polyphase electrical receiver with at least three phases, comprising at least one block of two converter arms, wherein a half-arm of a converter arm comprises: a first set of P2 switches in series; a second set of P2 switches in series; and a third set of diodes, arranged between the first set and the second set, comprising M2 subsets in series, indexed i[[1; M]], respectively comprising N.sub.i2 diodes in parallel.

Claims

1. A switched-mode power converter configured to control at least one phase of a polyphase electrical receiver with at least three phases, comprising at least one block of two converter arms, wherein a half-arm of a converter arm comprises: a first set (ENS1) of P2 switches (I1, I2) in series; a second set (ENS2) of P2 switches (I3, I4) in series, the second set (ENS2) being electrically connected in parallel between a power supply line (DCBUS+, DCBUS) of a coplanar electrical power supply (DCBUS) and a power interface; and a third set (ENS3) of diodes, arranged between the first set (ENS1) and the second set (ENS2), comprising M2 subsets (SE1, SE2, . . . , SEM) in series, indexed i[[1; M]], respectively comprising N.sub.i2 diodes in parallel, said third set (ENS3) being electrically connected between the power interface and the other power supply line (DCBUS+, DCBUS) of the coplanar electrical power supply (DCBUS).

2. The switched-mode power converter according to claim 1, wherein the M subsets comprise a same number N.sub.i of diodes in parallel.

3. The switched-mode power converter according to claim 1, comprising at least one temperature sensor.

4. The switched-mode power converter according to claim 1, wherein the switches of the first set (ENS1) are aligned and/or the switches of the second set (ENS2) are aligned and/or the subsets (SE1, SE2) of diodes of the third set (ENS3) are aligned.

5. The switched-mode power converter according to claim 1, wherein a block of two arms comprises a coplanar electrical power supply (DCBUS), provided with a positive line (DCBUS+) and a negative line (DCBUS), arranged so as to separate two arms of the converter, and comprising a power interface for each arm, each power interface being arranged such that the two half-arms of the corresponding arm are situated between the coplanar electrical power supply (DCBUS) and the corresponding power interface.

6. The switched-mode power converter according to claim 5, wherein two half-arms forming an arm of a block of two arms of the converter, comprise a positive half-arm comprising a third set (ENS3) connected between the negative line (DCBUS) of the coplanar electrical power supply (DCBUS) and the corresponding power interface, and a first set (ENS1) and a second set (ENS2) connected between the positive line (DCBUS+) of the coplanar electrical power supply (DCBUS) and the corresponding power interface, and a negative half-arm comprising a third set (ENS3) connected between the positive line (DCBUS+) of the coplanar electrical power supply (DCBUS) and the corresponding power interface, and a first set (ENS1) and a second set (ENS2) connected between the negative line (DCBUS) of the coplanar electrical power supply (DCBUS) and the corresponding power interface.

7. The switched-mode power converter according to claim 6, wherein a negative half-arm of an arm of a block of two arms of the converter is arranged facing a positive half-arm of the other arm of the block of two arms of the converter, relative to the coplanar electrical power supply (DCBUS).

8. The switched-mode power converter according to claim 1, wherein, when the number of arms is odd, the converter comprises said blocks of two arms, and a block of two arms provided with an additional arm.

9. The switched-mode power converter according to claim 8, wherein said block of two arms is provided with an additional arm comprising two half-arms arranged on either side of the extended coplanar electrical power supply (DCBUS), and a power interface of said additional arm comprising respectively, for each of the two half-arms, a part arranged such that the corresponding half-arm is situated between the coplanar electrical power supply (DCBUS) and said part of the corresponding power interface.

10. The switched-mode power converter according to claim 8, wherein said block of two arms provided with an additional arm also comprises an additional portion (DCBUSadd) of coplanar electrical power supply (DCBUS) arranged at one end and in a different direction from the rest of the coplanar electrical power supply, and a power interface of said additional arm arranged such that said additional arm is situated between said additional portion (DCBUSadd) of coplanar electrical power supply and said corresponding power interface.

11. The switched-mode power converter according to claim 10, wherein said additional portion (DCBUSadd) of coplanar electrical power supply (DCBUS) is substantially at right angles to the rest of the coplanar electrical power supply.

12. The switched-mode power converter according to claim 1, wherein it is hybrid.

13. The switched-mode power converter according to claim 1, wherein the switches comprise at least one insulated gate bipolar transistor and/or at least one insulated gate field effect transistor.

14. The switched-mode power converter according to claim 1, said converter being an inverter or a chopper.

15. A control system of at least one electrical cylinder actuator of a space launch vehicle comprising at least one switched-mode power converter according to claim 1, the electrical receiver being an electric motor and the power converter being an inverter.

16. A space launch vehicle provided with a system according to claim 15.

17. A control system of at least one steering device for antennas or solar panels of a satellite comprising at least one switched-mode power converter according to claim 1, the electrical receiver being an electric motor and the power converter being an inverter.

18. A satellite provided with a control system according to claim 17.

19. A power supply system of a satellite comprising at least one switched-mode power converter according to claim 1, the electrical receiver being a polyphase transformer and the power converter being an inverter or chopper.

20. A satellite provided with a power supply system according to claim 19.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood on studying a few embodiments described as nonlimiting examples and illustrated by the attached drawings in which:

(2) FIGS. 1a and 1b schematically illustrate the five moments of a switching period of the electrical voltage in the operation of an inverter H bridge for a positive phase electrical current of an electrical receiver;

(3) FIGS. 2a and 2b schematically illustrate the five moments of a switching period of the electrical voltage in the operation of an inverter H bridge for a negative phase electrical current of an electrical receiver;

(4) FIGS. 3a and 3b schematically illustrate the seven moments of a switching period of the electrical voltage in the operation of an inverter for an electrical receiver with three phases and neutral point;

(5) FIGS. 4a and 4b respectively illustrate a detailed and synthetic half-arm of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2, according to one aspect of the invention;

(6) FIGS. 4c, 4d, 4e, 4f, 4g, 4h, 4i and 4j illustrate, alternatively in detail and schematically, a half-arm of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2, according to various aspects of the invention;

(7) FIGS. 5a and 5b represent an arm of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2, and FIG. 5c represents a block of two arms, that can for example be used as H bridge or as double arm of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2 according to aspects of the invention;

(8) FIGS. 6a and 6b represent examples of production of a block of two arms provided with an additional arm for an odd total number of arms, according to various aspects of the invention;

(9) FIGS. 7a and 7b illustrate the circulations of the electrical currents in a block of two arms used as H bridge for an electrical receiver phase respectively for a positive electrical current and a negative electrical current; and

(10) FIG. 8a illustrates the case of an odd number of phases, in this case three phases and a neutral of the electrical receiver; and

(11) FIGS. 8b and 8c illustrate the circulations of the electrical currents in a block of FIGS. 6a and 6b with an electrical receiver with three phases and neutral.

(12) In the different figures, the elements that have identical references are identical. In the following examples, N is 2, but obviously the examples described apply, as a variant, to any value of N.

DETAILED DESCRIPTION

(13) FIGS. 1a and 1b represent the five moments of a switching period of the electrical voltage in the operation of an inverter H bridge for a positive phase electrical current of an electrical receiver. A positive phase electrical current denotes a current incoming via the Active terminal of the phase, identified by a large dot in the figures, and outgoing via the Return terminal of the phase. The Active and Return designation of the terminals of the phase is determined by the manufacturer of the electrical receiver as a function of the direction of the magnetic field developed by the phase within the electrical receiver.

(14) FIG. 1a represents an inverter H bridge controlling a phase Phase of an electrical receiver such as an electric motor comprising a positive electrical power supply DCBUS+ and a negative electrical power supply DCBUS, and the two arms of the H bridge, Bras_1 and Bras_2.

(15) The first arm Bras_1 of the H bridge comprises two switches I.sub.1a, I.sub.1b and two diodes D.sub.1a, D.sub.1b, and the second arm Bras_2 of the H bridge comprises two switches I.sub.2a, I.sub.2b and two diodes D.sub.2a, D.sub.2b.

(16) FIG. 1b represents five successive moments T.sub.1, T.sub.2, T.sub.3, T.sub.4 and T.sub.5 of a switching period of a positive phase electrical current in the H bridge, for the electrical voltages measured respectively at the points S1 and S2 relative to the DCBUS power supply line of the two arms Arm_1, Arm_2.

(17) The moments T.sub.1 and T.sub.5 correspond to the cases of the switches ha of the first arm Arm_1 and I.sub.2a of the second arm Arm_2 closed or active, in which the phase electrical current is looped back through the positive power supply line DCBUS+; these delays correspond to a positive freewheel, as illustrated by the dotted line arrow F1.

(18) Freewheel should be understood to mean the following. If a certain level of electrical current is required to be passed into an inductance or induction coil from an electrical voltage source, the best way is to take a switch and to deliver to the inductance regular voltage pulses whose value, in volts, and duration, in seconds, cause the electrical current in the inductance to be increased according to the law di/dt=e/L, in which i represents the intensity of the electrical current in amperes, L represents the inductance in henrys, and e represents the electromotive force, in volts. The problem, with an inductance, is that the electrical current cannot be interrupted abruptly; in fact, according to the same law, rapidly cancelling an existing electrical current requires an infinite voltage to be developed at the terminals of the inductance. Also, an inductance passed through by an electrical current i contains a stored energy W= Li.sub.2; as long as the electrical current circulates, this energy remains stored in the inductance, including if it is short-circuited; by contrast, if an external circuit forces it to develop the electrical voltage, its energy decreases. Also, to power an inductance, it is necessary to alternate the power supply periods of the inductance with so-called freewheel periods, during which the electrical current which was previously circulating in the inductance is maintained by an external circuit, under the lowest possible voltage, so as to conserve the energy in the inductance.

(19) The freewheel, somewhat as in the case of a bicycle, is a period during which the electrical current circulates without leading to a notable increase or reduction of the energy stored in the inductance.

(20) The moments T.sub.2 and T.sub.4 correspond to the cases of the switches ha of the first arm Arm_1 and I.sub.2b of the second arm Arm_2 closed or active, in which the phase electrical current is derived from the positive power supply line DCBUS+ to the negative power supply line DCBUS; these delays correspond to the transfer of energy, as illustrated by the dotted line arrow F2.

(21) The moment T.sub.3 corresponds to the cases of the switches I.sub.1b of the first arm Arm_1 and I.sub.2b of the second arm Arm_2 closed or active, in which the phase current is looped back through the negative power supply line DCBUS; this delay corresponds to a negative freewheel, as illustrated by the solid or continuous line arrow F3.

(22) FIGS. 2a and 2b represent the five moments of a switching period of the electrical voltage in the operation of an inverter H bridge for a negative phase electrical current of an electrical receiver. A negative phase electrical current designates a current incoming through via the Return terminal of the phase and outgoing via the Active terminal of the phase, identified by a dot in the diagram. The Active and Return designation of the terminals of the phase is determined by the manufacturer of the electrical receiver as a function of the direction of the magnetic field developed by the phase within the electrical receiver.

(23) FIG. 2a represents an inverter H bridge controlling a phase Phase of an electrical receiver such as an electric motor comprising a positive electrical power supply DCBUS+ and a negative electrical power supply DCBUS, and the two arms of the H bridge, Bras1 and Bras2.

(24) The first arm Arm_1 of the H bridge comprises two switches I.sub.1a, I.sub.1b and two diodes D.sub.1a, D.sub.1b, and the second arm Arm_2 of the H bridge comprises two switches I.sub.2a, I.sub.2b and two diodes D.sub.2a, D.sub.2b.

(25) FIG. 2b represents five successive moments T.sub.1, T.sub.2, T.sub.3, T.sub.4 and T.sub.5 of a switching period of a negative phase electric current in the H bridge, for the electrical voltages measured respectively at the points S1 and S2 relative to the DCBUS power supply line of the two arms Arm_1, Arm_2.

(26) The moments T.sub.1 and T.sub.5 correspond to the cases of the switches ha of the first arm Arm_1 and I.sub.2a of the second arm Arm_2 closed or active, in which the phase electrical current is looped back through the positive power supply line DCBUS+; these delays correspond to a positive freewheel, as illustrated by the broken line arrow F4.

(27) The moments T.sub.2 and T.sub.4 correspond to the cases of the switches I.sub.1b of the first arm Arm_1 and I.sub.2a of the second arm Arm_2 closed or active, in which the phase electrical current is derived from the positive power supply line DCBUS+ to the negative power supply line DCBUS; these delays correspond to the transfer of energy, as illustrated by the dotted line arrow F5.

(28) The moment T.sub.3 corresponds to the cases of the switches I.sub.1b of the first arm Arm_1 and I.sub.2b of the second arm Arm_2 closed or active, in which the phase electrical current is looped back through the negative power supply line DCBUS; this delay corresponds to a negative freewheel, as illustrated by the solid or continuous line arrow F6.

(29) FIGS. 3a and 3b represent the seven moments of a switching period of the electrical voltage in the operation of an inverter with three arms for an electrical receiver such as an electric motor with three phases Phase1, Phase2, Phase3, and a neutral point Neutral.

(30) FIG. 3a represents an inverter with three arms Arm_1, Arm_2 and Arm_3 comprising a positive electrical power supply DCBUS+ and a negative electrical power supply DCBUS.

(31) The first arm Arm_1 of the inverter comprises two switches I.sub.1a, I.sub.1b and two diodes D.sub.1a, D.sub.1b, the second arm Arm_2 of the H bridge comprises two switches I.sub.1a, I.sub.2b and two diodes D.sub.2a, D.sub.2b, and the third arm Arm_3 comprises two switches I.sub.3a, I.sub.3b and two diodes D.sub.3a, D.sub.3b.

(32) FIG. 3b represents seven successive moments T.sub.1, T.sub.2, T.sub.3, T.sub.4, T.sub.5, T.sub.6, and T.sub.7 of a switching period of a positive phase electrical current in the inverter, for the electrical voltages measured respectively at the points S1, S2 and S3 relative to the DCBUS power supply line of the three arms Arm_1, Arm_2, and Arm_3.

(33) The operation of an inverter with M phases breaks down into 2M+1 periods, in this particular case in the case described, the operation of an inverter with three phases breaking down into seven moments or seven successive delays T.sub.1, T.sub.2, T.sub.3, T.sub.4, T.sub.5, T.sub.6, and T.sub.7.

(34) FIG. 3b below shows the operation of a three-phase inverter Phase1, Phase2, Phase3 with three arms Arm_1, Arm_2, and Arm_3 which comprises seven operating periods T.sub.1, T.sub.2, T.sub.3, T.sub.4, T.sub.5, T.sub.6, and T.sub.7 (for the needs of the explanation, its operation is set at +15, which leads to a distribution of the electrical currents in the respective proportions of +97%, 70% and 27% in its cosinusoidal three-phase reference frame).

(35) The moments T.sub.1 and T.sub.7 correspond to the cases of the switches ha of the first arm Arm_1, I.sub.2a of the second arm Arm_2 and I.sub.3a of the third arm Arm_3 closed or active, in which the phase electrical currents are looped back through the positive power supply line DCBUS+, this time corresponds to a positive freewheel as illustrated by the arrows F7, F8 and F9.

(36) The moments T.sub.2 and T.sub.6 correspond to the cases of the switches ha of the first arm Arm_1, I.sub.2a of the second arm Arm_2, and I.sub.3b of the third arm Arm_3 closed or active, in which the electrical current of the phase Phase3 is derived from the DCBUS+ power supply, this is a time during which the transfer of energy is applied while the electrical current of the phase Phase2 is still in positive freewheel mode; the electrical current of the phase Phase1 is the sum of the other two currents as illustrated by the arrows F10, F8 and F12.

(37) The moments T.sub.3 and T.sub.5 correspond to the cases of the switches ha of the first arm Arm_1, I.sub.2b of the second arm Arm_2, and I.sub.3b of the third arm Arm_3 closed or active, in which the electrical currents of the phases Phase2 and Phase3 are derived from the DCBUS+ power supply, this is a time during which the transfer of energy is applied; the electrical current of the phase Phase1 is the sum of the other two electrical currents, as illustrated by the arrows F10, F11 and F12.

(38) The moment T.sub.4 corresponds to the case of the switches lib of the first arm Arm_1, I.sub.2b of the second arm Arm_2, and I.sub.3b of the third arm Arm_3 closed or active, in which the phase electrical currents of the phases Phase1, Phase2, Phase3 are looped back through the negative power supply line DCBUS, this delay corresponds to a negative freewheel, as illustrated by the arrows F13, F14 and F15.

(39) As described above, the phase current passes, in turn, through the top and the bottom of the arms Arm_1 and Arm_2 with rise and fall times of the order of 1 A/ns. Also, the stray inductances distributed in the circuit generate overvoltages at a rate of 1 volt/nH. These stray inductances are distributed in the inverter arms but also in the DCBUS links.

(40) Given that a single wire develops 10 nH/cm, without precautions, an inverter half-arm of 15 cm is the seat of overvoltages of the order of 150 V, in other words, more than half of the aeronautic voltage (270 V dc), even the entirety of the power supply voltage for some launch vehicle applications (Ariane 5ME and Ariane 6, top stage: 150 V).

(41) These overvoltages require the components to be oversized and the production technologies of the equipment to also withstand the rate of charge in the components that they generate.

(42) For example, an inverter powered by 320 V batteries can be produced with 650V chips, with a surface area of 100 mm.sup.2 for the IGBTs and of 38 mm.sup.2 for the diodes. When the overvoltages require the use of components with a higher voltage withstand strength, 1200 V chips must be used; the withstand strength to a higher voltage means having thicker chips. Now, the diodes, just like the IGBTs, conduct the current in the thickness of the chip so that, to conserve the same conduction losses, the surface area of the IGBT changes to 193 mm.sup.2 and that of the diode to 81 mm.sup.2.

(43) Currently, the market does not offer catalogue-available hybrid modules, of high reliability, even of industrial grade, which incorporate tolerance to failures by redundancy.

(44) It is thus necessary to construct a discrete solution which, intrinsically, would be neither extremely compact and therefore subject to the overvoltages, nor thermally optimized and therefore oversized, i.e. develop a specific hybrid circuit which will make it possible to exploit all the advantages of this invention.

(45) The present invention implements the minimum of redundancy of the power components necessary to resolve the problem of tolerance to failures without reconfiguration.

(46) Through the optimisation of the redundancy, the present invention makes it possible to define a compact implementation which, by drastically reducing the stray inductances, enhances the performance levels of the inverter while reducing the switching overvoltages thereof.

(47) The proposed architecture is applied to motors with at least three phases, controlled by H bridges; it is based on the following three observations: the polyphase motors with n phases, controlled by the vector control technique (Park, Concordia transforms), have the facility to be able to operate naturally on n1 phases when the failed phase is lost by open circuit; no failure mode can short-circuit the battery without risking a failure propagation; and the loss of a freewheeling diode causes the inductance of the corresponding phase of the motor to develop a voltage that risks propagating the failure.

(48) On this basis, the tolerance to simple failure of the proposed solution relies on two means: the power switches are redundant in series.

(49) Thus, an open-circuit failure of a switch corresponds to an open phase, which is acceptable, and a short-circuit failure is circumvented by the series redundancy, which is required. Furthermore, a short-circuit failure of a switch does not cause a short-circuit of the battery, or of the phase of the motor, which is required.

(50) The power diodes are redundant in series and parallel.

(51) Thus, an open-circuit failure of a diode is compensated by the parallel diode, which is required, and a short-circuit failure is circumvented by the series redundancy, which is required. Furthermore, the short-circuit failure of a diode does not cause a short-circuit of the battery, or of the phase of the motor, which is required.

(52) All the ideas developed in the present invention are applicable to the inverters produced with discrete components, but, the implementation of the present invention in a power hybrid makes it possible to derive maximum benefit from the stray inductance reduction techniques by virtue of the multiplying effect of the increased compactness of the solution through hybridization.

(53) Also, the grouping together or the separation of the power components according to their negative or positive temperature coefficient makes it possible to optimise the division of the current between the components.

(54) FIGS. 4a and 4b respectively illustrate a detailed half-arm 4a and a synthetic half-arm 4b of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2, like an inverter, a chopper, or a dimmer, configured to control at least one phase of a polyphase electrical receiver with at least three phases, such as an electric motor or a transformer, comprising at least two converter arms. This embodiment is in no way limiting.

(55) The switches can comprise at least one insulated gate bipolar transistor or IGBT, and/or at least one insulated gate field-effect transistor or MOSFET, which stands for Metal Oxide Semiconductor Field Effect Transistor. In the examples described, the switches are insulated gate bipolar transistors or IGBT, in a nonlimiting manner.

(56) FIG. 4a shows a detailed representation of a half-arm 40 of a switched-mode power converter, when P=2, M=2, N.sub.1=2 and N.sub.2=2.

(57) Such a half-arm 40 of a switched-mode power converter arm comprises a first set ENS1 of P2 switches in series, in this case two switches I1, I2 arranged in series, a second set ENS2 of P2 switches in series, in this case two switches I3, I4, arranged in series, and a third set ENS3 of diodes, arranged between the first set ENS1 and the second set ENS2, comprising M2 subsets SE1, SE2, . . . SEM, indexed i[[1; M]], in this case two subsets SE1, SE2 in series, respectively comprising N.sub.i2 diodes in parallel, in this case, respectively, two diodes in parallel, D1 and D2, and D3 and D4.

(58) The various connections are represented by connection wires 41a, and represented by low-level connection wires 41b.

(59) The emitter connections E1, E2 of the switches I1, I2, I3, I4 are used as return for the control of the switches I1, I2, I3, I4.

(60) The gate connections G1, G2, G3, G4 of the transistor switches I1, I2, I3, I4 are used for the control of the switches I1, I2, I3, I4.

(61) The mid-point DT1 of the series connection of the subsets SE1, SE2 of diodes can be used for self-testing.

(62) The external connections of this half-arm 40 are referenced A, B, C, D, E and F, in order to be able to identify them in the following summary representations.

(63) FIG. 4b is a summary version of FIG. 4a.

(64) One of the main characteristics of the diodes is their negative temperature coefficient. That means that the forward voltage recorded at the terminals of a diode past through by a given electrical current decreases as the temperature of the diode increases.

(65) In the case of a parallel diode connection, the division of the electrical current between them depends on their individual current/voltage characteristic. If a temperature difference occurs between the diodes, the hottest diodes are passed through by a greater current which, in return, further heats up said diodes with the possibility of a runaway.

(66) Also, the proposed implementation prescribes grouping together the diodes in parallel on the same copper surface so that, when one diode heats up, it also heats up the other diodes, thus tending to maintain the good distribution of the current.

(67) Unlike the diodes, one of the main characteristics of the IGBTs or switches is their positive temperature coefficient. That means that the electrical voltage between the collector and the emitter recorded at the terminals of a saturated IGBT, passed through by a given collector current, increases as the temperature of the IGBT increases.

(68) Just as for the diodes, in the case of a parallel IGBT connection, the division of the current between them depends on their individual current/voltage characteristic. By contrast, if a temperature difference occurs between the IGBTs, the hottest IGBTs are passed through by a lower current which, in return heats up said IGBTs less which makes it possible, if each IGBT can have its temperature changed freely, to stabilise the division of the current between the IGBTs.

(69) Also, the proposed implementation prescribes dissociating the IGBTs in parallel on different and separate copper surfaces, so that, in the case where one IGBT heats up, the thermal segregation with the other IGBTs allows it to heat up freely, without interfering with the other IGBTs, thus tending to maintain the good distribution of the current.

(70) It should be noted here that the substrate used is composed of a layer of copper, on which the chips are soldered, resting on a ceramic of alumina type which is mounted on a second layer of copper in direct or indirect contact with a heat sink. Through the presence of the ceramic which has a higher thermal resistance than that of the top copper face in the stack of the power hybrid, the thermal power is preferentially in all the top copper surface (horizontally), which causes the heating of the other elements common to this copper layer and which is, specifically, the effect sought for the diodes.

(71) By contrast, since the interfaces below the ceramic are good thermal conductors, the heat is transmitted substantially equally horizontally and vertically in the ceramic so that, from a distance equal to the thickness of the ceramic, there will be no thermal crosstalk; which is the effect sought for the IGBTs. As indicated previously, the phase current is switched between diodes and power switches so, since the rate of variation of the current is rapid, the lesser stray inductance generates the lesser switching over voltages.

(72) In the case of a positive current, the phase current is switched respectively between the groups ENS1 and ENS2, on the one hand, and the group ENS3, for the output 42 in FIG. 4C.

(73) The present invention prescribes: assembling the group of diodes connected in parallel on a single surface; and placing the group of diodes in the middle of the group of switches which is split into two branches in which the current is distributed. The rest of the scheme being implemented according to the same principle.

(74) The phase current circulates either in the central branch composed of the group of diodes ENS3, or, is divided up between the two branches of IGBTs ENS1, ENS2.

(75) The strong mutual inductive coupling of the branch ENS3 with diodes on cells ENS1, ENS2 with IGBTs (and vice versa), renders the switching inductance very low, which is the aim sought.

(76) The principles set out previously make it possible to design a circuit allowing for a powerful optimisation of the design of a power hybrid.

(77) During switching, in so-called freewheel phases, the currents are exchanged between the inverter arms of the H bridge through the power supply lines.

(78) According to the stray inductance of these lines, overvoltages are generated at the terminals of the active components.

(79) The present invention proposes placing the inverter arms back-to-back, so that the exchanges of current between the two inverter arms are as direct as possible, therefore with the least possible inductance.

(80) FIGS. 4c, 4d, 4e, 4f, 4g, 4h, 4i and 4j illustrate, alternatively in detail and schematically, a half-arm of a switched-mode power converter, when P=2, M=2, N.sub.1=2, and N.sub.2=2, such as an inverter, a chopper, or a dimmer, configured to control at least one phase of a polyphase electrical receiver with at least three phases, such as an electric motor or a transformer, comprising at least two converter arms, according to various aspects of the invention.

(81) These figures illustrate a half-arm 40 of FIGS. 4a and 4b, connected in various ways with power interfaces and a coplanar electrical power supply DCBUS.

(82) FIG. 4c represents a positive half-arm 41 of a switched-mode power converter, when P=2, M=2, N.sub.1=2 and N.sub.2=2, for a positive use, i.e. in which the first and second sets ENS1, ENS2 are connected to a positive power supply line DCBUS+, in a left hand implementation.

(83) Such a positive half-arm 41 comprises a half-arm 40 whose first and second sets ENS1, ENS2 are connected to a positive power supply line DCBUS+ of a coplanar electrical power supply DCBUS, comprising a positive line DCBUS+ and a negative line DCBUS, arranged so as to separate two arms of the converter, and comprising a power interface for each arm, such as a busbar or distribution bar.

(84) Each power interface is arranged such that the two half-arms of the corresponding arm are situated between the coplanar electrical power supply DCBUS and the corresponding power interface. The different connections are represented by connection wires 41a and represented by low-level connection wires 41b.

(85) In the present implementation of a half-arm, the power interface or phase output 42 is represented on the left.

(86) FIG. 4d is a summary version of FIG. 4c.

(87) FIG. 4e represents a positive half-arm 43 of a switched-mode power converter, when P=2, M=2, N.sub.1=2 and N.sub.2=2, for a positive use, i.e. in which the first and second sets ENS1, ENS2, are connected to a positive power supply DCBUS+, in a right hand implementation.

(88) Such a positive half-arm 43 comprises a half-arm 40 whose first and second sets ENS1, ENS2 are connected to the positive line DCBUS+ of a coplanar electrical power supply DCBUS, comprising a positive line DCBUS+ and a negative line DCBUS, arranged so as to separate two arms of the converter, and comprising a power interface for each arm, such as a busbar or distribution bar.

(89) Each power interface is arranged such that the two half-arms of the corresponding arm are situated between the coplanar electrical power supply DCBUS and the corresponding power interface. The various connections are represented by connection wires 41a, and represented by low-level connection wires 41b.

(90) In the present implementation of a half-arm, the power interface 44 is represented on the right.

(91) FIG. 4f is a summary version of FIG. 4e.

(92) FIG. 4g represents a negative half-arm 45 of a switched-mode power converter, when P=2, M=2, N.sub.1=2 and N.sub.2=2, for a negative use, i.e. in which the first and second sets ENS1, ENS2 are connected to a negative power supply line DCBUS, in a left hand implementation.

(93) Such a negative half-arm 45 comprises a half-arm 40 whose first and second sets ENS1, ENS2 are connected to a negative power supply line DCBUS of a coplanar electrical power supply DCBUS, comprising a positive line DCBUS+ and a negative line DCBUS, arranged so as to separate two arms of the converter, and comprising a power interface for each arm, such as a busbar or distribution bar.

(94) Each power interface is arranged such that the two half-arms of the corresponding arm are situated between the coplanar electrical power supply DCBUS and the corresponding power interface. The various connections are represented by connection wires 41a, and represented by low-level connection wires 41b.

(95) In the present implementation of a half-arm, the power interface or phase output 46 is represented on the left.

(96) FIG. 4h is a summary version of FIG. 4g.

(97) FIG. 4i represents a negative half-arm 47 of a switched-mode power converter, when P=2, M=2, N.sub.1=2 and N.sub.2=2, for a negative use, i.e. in which the first and second sets ENS1 and ENS2 are connected to a negative power supply line DCBUS, in a right hand implementation.

(98) Such a negative half-arm 47 comprises a half-arm 40 whose first and second sets ENS1, ENS2 are connected to the negative line DCBUS of a coplanar electrical power supply DCBUS, comprising a positive line DCBUS+ and a negative line DCBUS, arranged so as to separate two arms of the converter, and comprising a power interface for each arm, such as a busbar or distribution bar.

(99) Each power interface is arranged such that the two half-arms of the corresponding arm are situated between the coplanar electrical power supply DCBUS and the corresponding power interface. The various connections are represented by connection wires 41a, and represented by low-level connection wires 41b.

(100) In the present implementation of a half-arm, the power interface 48 is represented on the right.

(101) FIG. 4f is a summary version of FIG. 4e.

(102) For the following figures, for representation purposes, only summary versions are used.

(103) FIGS. 5a and 5b represent, in detail and in summary form, an arm of a switched-mode power converter with P=2, M=2, N.sub.1=2 and N.sub.2=2, and FIG. 5c represents a block of two arms that can for example be used as H bridge or as double-arm of a switched-mode power converter, according to one aspect of the invention.

(104) FIG. 5b represents an arm 50 of a switched-mode power converter with P=2, M=2, N.sub.1=2 and N.sub.2=2 with left-hand implementation, which is composed of two half-arms 41, 45, one of them 41, the positive half-arm, according to FIG. 4c or 4d and the other, 45, the negative half-arm, according to FIG. 4g or 4h. The power interface DCBUS corresponds to the power interfaces 42 or 46, in this case identical.

(105) FIG. 5a represents an arm 52 of a switched-mode power converter with P=2, M=2, N.sub.1=2 and N.sub.2=2 with right hand implementation, which is composed of two half-arms 47, 43, one of them, 43, the positive half-arm, according to FIG. 4d or 4e, and the other, 47, the negative half-arm, according to FIG. 4i or 4j. The power interface 53 corresponds to the power interfaces 44 or 48, in this case identical.

(106) FIG. 5c represents a block 55 of two arms 50, 52, being the combination of an arm 50 implemented on the left according to FIG. 5b and an arm 52 implemented on the right according to FIG. 5a, that can for example be used as H bridge or as double-arm of a switched-mode power converter, according to one aspect of the invention. Obviously, all these embodiments are nonlimiting, because they can be adapted to different geometries.

(107) FIGS. 6a and 6b represent examples of production of a block 60 comprising a block 55 of two arms according to FIG. 5c, provided with an additional arm 57, 62 for an odd total number of arms, according to two nonlimiting embodiments.

(108) The embodiment of FIG. 6a represents a block 60 comprising a block 55 of two arms, according to FIG. 5c, provided with an additional arm 57 comprising two half-arms 57a, 57b arranged on either side of the extended coplanar electrical power supply DCBUS. In the embodiment, the additional arm 57 comprises a negative half-arm with left hand implementation 57a and a positive half-arm with right hand implementation 57b. The additional arm 57 further comprises a power interface 58 comprising, respectively, for each of the two half-arms 57a, 57b, a part 58a, 58b arranged such that the corresponding half-arm 57a, 57b is situated between the coplanar electrical power supply DCBUS and the corresponding part of the power interface, or, in other words, the extension of the power interface 58a, 58b. In this case, the power interface 58 of the additional arm 57 therefore comprises three parts 58a, 58b and 58c forming a U.

(109) The embodiment of FIG. 6b represents a block 60 comprising a block 55 of two arms, according to FIG. 5c, provided with an additional arm 62. The block 60 further comprises an additional portion DCBUSadd of coplanar electrical power supply arranged at one end and in a different direction from the rest of the coplanar electrical power supply DCBUS, and a power interface 63 of the additional arm 62 arranged such that the additional arm 62 is situated between said additional portion DCBUSadd of coplanar electrical power supply and said corresponding power interface 63.

(110) The additional portion DCBUSadd of coplanar electrical power supply can advantageously be substantially at right angles to the rest of the coplanar electrical power supply DCBUS.

(111) In this case, the coplanar electrical power supply DCBUS, DCBUSadd form an upside down T.

(112) During switching, in the so-called freewheel phases, the currents are exchanged between the inverter arms of the H bridge through the power supply lines DCBUS+, DCBUS. Depending on the stray inductance of these lines, overvoltages will be generated therein.

(113) The present invention proposes placing the inverter arms back-to-back, so that the exchanges of currents between the two inverter arms are as direct as possible, therefore with the least possible induction.

(114) FIG. 7a illustrates the circulations of the electrical currents in a block 55 of two arms used as H bridge for an electrical receiver phase Phase, in the case of a positive phase electrical current.

(115) For the freewheel in the positive power supply bar DCBUS+, the current follows the path indicated by the broken line arrows.

(116) For the freewheel in the negative power supply bar DCBUS, the current follows the path indicated by the solid or continuous line arrows.

(117) The dotted line arrows indicate the circulation of the current, during the active period. During this period, the current is derived from the DCBUS source at the voltage V.sub.DCBUS, which corresponds to the energy delivered by the source to the phase.

(118) FIG. 7b illustrates the circulations of the electrical currents in a block 55 of two arms used as H bridge for an electrical receiver phase Phase, in the case of a negative phase electrical current.

(119) For the freewheel in the positive power supply bar, the current follows the path indicated by the dotted line arrows.

(120) For the freewheel in the negative power supply bar, the current follows the path indicated by the solid or continuous line arrows.

(121) The dotted line arrows indicate the circulation of the current, during the active period. During this period, the current is derived from the DCBUS source at the voltage V.sub.DCBUS, which corresponds to the energy delivered by the source to the phase.

(122) FIG. 8b illustrates the case of an odd number (2M+1) of phases of the electrical receiver, in this case three phases Phase1, Phase2, Phase3, and a neutral of the electrical receiver.

(123) The electrical receiver, for example the electric motor revolving over 360, each phase (taking the three-phase case) is phase-shifted by 120 but each phase sees a current of type I=Io cos (t+) in which is respectively 0, 120 and 240.

(124) Noteworthy angles (every 60) can be found that follow the table of FIG. 8a, so it is possible to more easily study the circulation of the switched currents for the noteworthy angles.

(125) Also, the connection is automatically with a neutral Neutral as represented in the drawing of FIG. 8b.

(126) FIGS. 8b and 8c illustrate the circulations of the electrical currents in a block of FIGS. 6a and 6b with an electrical receiver with three phases and neutral, in the case of the noteworthy angle 0 in which the three currents have the respective proportions: 1, 0.5, 0.5.

(127) In light of the two FIGS. 8b and 8c of current circulation, the electrical switching currents of the odd phase return through the DCBUS busbar (DCBUS+ and DCBUS); if the coplanar busbar is of good quality, the inductance is very low since the path difference between the solid or continuous line, dotted line and broken line plots is minimal.

(128) The choice between an inverted T design of FIG. 8c and a U design of FIG. 8b will be dictated by the implementation for which the stray inductance of the DCBUS segment necessary to power the two half-arms of the odd phase will be the lowest.

(129) Also, the present invention addresses the failure tolerance requirement, including failures of the control circuits.

(130) By reducing to a minimum the stray inductances, the solution makes it possible to use components that are better dimensioned in terms of electrical voltage, which leads to lower Joules losses in the power converter, therefore a better efficiency and an optimal thermal dimensioning.

(131) By reducing the stray inductances to their minima, the present invention makes it possible to better exploit the power supply voltage.

(132) By favouring the compactness of the solution, the invention reduces the weight thereof, a criterion that is important in the world of launch vehicles and satellites.