# Patent

## Title
Power supply system with prioritized network selection

## Abstract

A power supply system with prioritized network selection is disclosed. In one aspect, the system can be connected to the output of N power supply networks (R1, . . . , RN), N being an integer greater than or equal to 2. It includes N controllable energy transfer members (T1, . . . , TN) each connected to a power supply network (R1, . . . , RN), control subsystem (14) for selecting one power supply network (R1, . . . , RN) by commanding the controllable member (T1, . . . , TN) connected to the selected power supply network (R1, . . . , RN) into a closed position, and energy storage subsystem capable of delivering a storage voltage (Ve). It may also comprise an energy converter connected to the output to the N controllable energy transfer members (T1, . . . , TN), the control subsystem being able to command the energy converter and the N controllable energy transfer members (T1, . . . , TN) to select at most one energy source from among the N power supply networks (R1, . . . , RN), as a function of the N input voltages (V1, . . . , VN) and the storage voltage (Ve).

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to French patent application no, 11-04093 filed on Dec. 23, 2011, the contents of which are incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power supply system, and more specifically, the system applies to the field of electronic equipment power supply systems from several distinct power supply networks. Such power supply systems are frequently used in particular in aeronautics, to supply power to electronic equipment of the avionics cabinet, flight data module, or other type.
2. Description of the Related Technology
Document FR 2 815 789 A1 describes a power supply system of the aforementioned type. The power supply system comprises a battery of capacitors forming the energy storage subsystem, as well as a diode switch to select a power supply network from among the N networks.
The power supply system is capable of selecting a power supply network from among the networks to which it is connected. It is capable of switching to a redundant network when the voltage delivered by an adapter associated with the selected power supply network is below a given threshold.
This makes it possible to switch toward a redundant power supply network during power line disturbances or outages on the output voltage from the system. The presence of the energy storage subsystem then limits the impact of such power line disturbances or outages on the output voltage of the system.
The selection between the power supply networks is made according to a priority order determined as a function of predetermined voltage thresholds associated with the output voltages of the controllable energy transfer members.
However, in a context of increasing the dynamics of the power supply networks in aeronautics, during outages or power line disturbances occurring on the selected network, the power supply system commands switching between the networks once the associated voltage threshold is crossed, even if it is not strictly necessary. This tends to needlessly wear out the various members of the power supply system and decrease their lifetime, as well as creating instabilities and disturbances in the power supply networks due to untimely switching, which is particularly restrictive when the power supply system is onboard an aircraft.
SUMMARY OF CERTAIN INVENTIVE ASPECTS
The aim of various aspects is therefore to limit the number of switches between the networks.
To that end, the inventive aspects relate to a power supply system of the aforementioned type, characterized in that it also comprises an energy converter connected to the output of the N controllable energy transfer members, the control subsystem being capable of controlling the energy converter and the N controllable energy transfer members to select at most one energy source from among the N power supply networks, as a function of the N input voltages and the storage voltage.
According to other advantageous aspects, the power supply system comprises one or more of the following features, considered alone or according to all technically possible combinations:

    
    
        the energy storage subsystem have a maximum storage capacity, the power supply networks are ordered by increasing energy levels, each energy level being predetermined and associated with the corresponding power supply network and having a positive value below the maximum storage capacity, and the control subsystem are adapted to select, as a priority, the power supply network associated with the highest energy level;
        voltage thresholds are respectively associated with the power supply networks, the control subsystem being capable of controlling the switching from a first power supply network to a second power supply network only if the second power supply network has an input voltage higher than the corresponding voltage threshold;
        the difference between two successive energy levels corresponds to the energy supplied by the energy storage subsystem to the energy converter during the outage, for a transparency duration unique to each power supply network, of the input voltage of the power supply network with the lowest associated energy level of the two energy levels;
        the control subsystem are adapted to command the switch from a first power supply network, the transparency duration of which is longer than a predetermined delay period, to a second power supply network during a outage of the input voltage of the first power supply network for a duration longer than the delay period;
        the storage voltage is representative of a quantity of energy of the energy storage subsystem, and the control subsystem are adapted to command the switch from a first power supply network to a second power supply network with a lower associated energy level, during a outage of the input voltage of the first power supply network, only if the quantity of energy of the energy storage subsystem is lower than the energy level associated with the first power supply network;
        the control subsystem are adapted to command the switch from a first power supply network to a second power supply network with a higher energy level only if the amount of energy of the energy storage subsystem is equal to the maximum storage capacity;
        the control subsystem are adapted to command the selection of no energy source by commanding all of the controllable energy transfer members into the open position;
        the energy storage subsystem have a maximum storage capacity, the control subsystem being able to inhibit the switch from a first power supply network, toward which switching was commanded from the selection of no energy source, to a second power supply network as long as the quantity of energy of the energy storage subsystem is not equal to the maximum storage capacity;
        the power supply system also comprises a shared power supply line having a selection voltage, the controllable energy transfer members are connected to the shared power supply line, and the control subsystem are capable of commanding the energy converter and the N controllable energy transfer members to select at most one energy source from among the N power supply networks, as a function of the N input voltages, of the storage voltage, of intermediate voltages delivered by the controllable energy transfer members, and of the selection voltage;
        the control members are adapted to command the switch to a secured state of the power supply network in which the controllable energy transfer members are all commanded into the open position, their command into the closed position being inhibited;
        the control subsystem are adapted to command the switch from the selection of no energy source to the secured state if at least one intermediate voltage is non-zero;
        the voltage thresholds are respectively associated with the power supply networks, the switching/selection subsystem being able to command the switch of a power supply network to the secured state if at least one controllable energy transfer member other than the controllable power transfer member associated with the power supply network has a non-zero intermediate voltage or if the selection voltage is zero whereas the input voltage of the power supply network is above the associated voltage threshold; and
        the power supply network also comprises a shared power supply line to which the controllable energy transfer members are connected, and the power supply system comprises N unidirectional diodes respectively connected between the output of the given controllable energy transfer member and the shared power supply line.
    
    


Various embodiments may have other features of interest as described below.



BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood upon reading the following description, provided solely as an example, and done in reference to the appended drawings, in which:
FIG. 1 is a diagrammatic illustration showing a power supply system comprising energy storage subsystem according to a first embodiment of the invention;
FIG. 2 is a diagrammatic illustration of a scale of energy levels of the energy storage subsystem according to the first embodiment of the invention;
FIG. 3 is a diagram of operating states of the power supply system of FIG. 1;
FIG. 4 is a view similar to that of FIG. 1 according to a second embodiment of the invention;
FIG. 5 is a view similar to that of FIG. 3 according to the second embodiment of the invention;
FIG. 6 is an illustration of a unidirectional diode according to a third embodiment;
FIG. 7 is a view similar to that of FIG. 6 according to a fourth embodiment of the invention; and
FIG. 8 is a view similar to that of FIG. 1 according to a fifth embodiment of the invention.



DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS
Hereafter, the indices i, j, k, etc. are used non-limiting and their usage context will be explained.
In reference to FIG. 1, a power supply system 10 designed to be onboard an aircraft is adapted to be connected at its input to N distinct power supply networks R1, . . . , RN, N being an integer greater than or equal to 2, each power supply network Ri delivering an input voltage Vi, being a positive integer comprised between 1 and N.
The power supply system 10 can select one of these power supply networks R1, . . . , RN at most as the energy source for the power supply system 10. It can command the switch from one power supply network Ri to another network Rj according to a switching logic, also called selection logic hereafter, and outlined below, j being an integer comprised between 1 and N and different from i, and the other power supply networks R1, . . . , RN being unused.
Lastly, the system 10 can be connected at its output to charges, such as electronic pieces of equipment, so as to deliver a DC output voltage Vout to them from the input voltage Vi delivered by the selected power supply network Ri. The output voltage Vout is preferably regulated.
The power supply system 10 comprises N controllable energy transfer members T1, . . . , TN, also called controllable power transfer members T1, . . . , TN or controllable members T1, . . . , TN, and control subsystem 14 for the members T1, . . . , TN. It also comprises a shared power supply line 15, an energy converter 16, and energy storage subsystem 18. It comprises N unidirectional diodes D1, . . . , DN connected between the controllable members T1, . . . , TN and the shared line 15.
In a known manner, each power supply network Ri delivers a DC or AC input voltage Vi, for example from an alternator, or from a battery, for example with a rated voltage equal to +28V.
The N controllable members T1, . . . , TN can transfer the electrical energy delivered by the power supply networks R1, . . . , RN to the power supply system 10, or on the contrary inhibit the transfer of the electrical energy to the power supply system.
Each controllable member Ti is connected to a corresponding power supply network Ri and can switch between an open position and a closed position. Each controllable member Ti is designed to be commanded into the open or closed position by the control subsystem 14.
The output of each controllable member T1, . . . , TN is connected to the shared power supply line 15, the line having a selection voltage USEL. The selection voltage USEL is a DC voltage.
Each controllable member Ti can receive the input voltage Vi supplied by the corresponding power supply network Ri and deliver an intermediate voltage Ui.
Each intermediate voltage Ui is a DC voltage, the controllable member Ti including a converter for converting AC voltage into DC voltage when the corresponding power supply network Ri is an alternating network.
During nominal operation of the power supply system 10, the selection voltage USEL of the shared power supply line 15 is equal to the intermediate voltage Ui corresponding to the selected network Ri.
In a known manner, each member Ti comprises:

    
    
        one or more electromechanical relay-type switches, or static switches of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or IGBT (Insulated Gate Bipolar Transistor) type, or
        a monodirectional insulated power converter, or
        a monodirectional non-insulated power converter, or
        a bidirectional insulated power converter, or
        a bidirectional non-insulated power converter.
    
    


The energy converter 16 can allow the transfer of electrical energy from the power supply networks R1, . . . , RN to the energy storage subsystem 18 and to the electronic equipment to which the power supply system 10 is connected as output. Furthermore, it is adapted to regulate the output voltage Vout to a stipulated voltage from a storage voltage Ve delivered by the energy storage subsystem 18 and the selection voltage USEL of the shared power supply line 15.
The energy converter 16 is connected in input to the shared power supply line 15 and delivers the output voltage Vout.
The converter 16 is, in a known manner, an insulated converter. Alternatively, the converter 16 is a non-insulated converter. Also alternatively, the converter 16 is a monodirectional converter. Alternatively, the converter 16 is a bidirectional converter.
The energy storage subsystem 18 are connected to the power supply line 15 via the energy converter 16.
The energy storage subsystem 18 can limit the impact, on the output voltage Vout, of outages of the voltage Vi occurring on the selected power supply network Ri.
The storage subsystem 18 can store the electrical energy coming from the power supply networks R1, . . . , RN by subsystem of the energy converter 16 or restore the electrical energy stored to the converter 16.
The energy storage subsystem 18 comprise, in a known manner, an aluminum electrochemical capacitor and/or one or more batteries and/or supercapacitor devices.
The energy storage subsystem 18 have a maximum energy storage capacity Emax. The storage voltage Ve delivered by the energy storage subsystem 18 to the energy converter 16, is representative of a quantity of energy E stored in the subsystem 18.
Alternatively, when the controllable members Ti have an intermediate voltage Ui close to the storage voltage Ve, which is for example the case when the controllable members Ti perform an energy conversion, the energy storage subsystem 18 are placed directly on the shared power supply line 15 and the converter 16 is eliminated.
In reference to FIG. 2, the power supply networks R1, . . . , RN are ordered by decreasing energy levels E1, . . . , EN, each energy level E1, . . . , EN being predetermined, associated with a corresponding power supply network R1, . . . , RN and having a positive value below the maximum energy storage capacity Emax. The control subsystem 14 are adapted to select, as a priority, the power supply network R1, . . . , RN associated with the highest energy level E1, . . . , EN.
The difference between two successive predetermined energy levels Eu−1 and Eu, u being an integer comprised between 1 and N, E0 corresponding to Emax corresponds to the energy supplied by the energy storage subsystem 18 to the energy converter 16 so as to offset the outage for a duration t(u) of the voltage Vu delivered by the selected power supply network Ru with the lowest energy level Eu from among the to networks Ru−1 and Ru. The duration t(u) is also called the transparency of the power supply network Ru, and is predetermined specifically for each power supply network Ru. This duration t(u) corresponds to the time interval occurring between the outage of the network Ru−1 and the switch to the power supply network Ru. This transparency t(u) is predetermined for a known output power of the power supply system 10 and a maximum turnoff time to be respected. The maximum turnoff time is for example defined by a standard.
Each unidirectional diode Di associated with a given power supply network Ri is arranged so as to be on in the direction of the transfer of energy from the power supply network Ri toward the energy converter 16 and to be blocked in the opposite direction when the power supply network Ri is not selected.
The diodes D1 make it possible to avoid a transfer of energy between the power supply networks R1, . . . , RN.
Alternatively, each unidirectional diode Di is associated with a switch capable of reducing the losses of the unidirectional diode Di when the corresponding power supply network Ri is selected. To that end, the switch is then closed on the unidirectional diode Di.
The control subsystem 14 are adapted to command the energy converter 16 to regulate the storage voltage Ve and command the controllable members T1, . . . , TN into the open or closed position to select at most one energy source from among the N energy supply networks R1, . . . , RN, as a function of the input voltages V1, . . . , VN and the storage voltage Ve.
To select the power supply network Ri, the control subsystem 14 can command the corresponding controllable member Ti into the closed position such that the member Ti communicates the electrical energy delivered by the power supply network Ri to the shared line 15. The control subsystem 14 are adapted to command the other controllable members Tk, for an integer k comprised between 1 and N and different from i, into the open position such that the other corresponding power supply networks Rk are then not used by the power supply system 10.
The control subsystem 14 for example comprise programmable logic circuits (not shown), of the microcontroller or FPGA (Field-Programmable Gate Array) type, capable of implementing the switching logic between the N power supply networks R1, . . . , RN to select one energy source at most. Complementarily, they comprise voltage comparators capable of detecting that voltage thresholds S1, . . . , SN associated with the input voltages V1, . . . , VN have been crossed, as described below. The voltage threshold values S1, . . . , SN are predetermined as a function of criteria, for example such as the minimum allowable working voltage for the controllable members T1, . . . , TN and/or the minimum allowable startup voltage on the power supply networks R1, . . . , RN.
The control subsystem 14 are also capable of controlling the switching from a first power supply network R1, . . . , RN to a second power supply network R1, . . . , RN only if the second power supply network R1, . . . , RN has an input voltage V1, . . . , VN above the corresponding voltage threshold S1, . . . , SN.
Furthermore, when the input voltage Vu of the selected power supply network Ru disappears for a duration longer than the transparency t(u) of that power supply network, the control subsystem 14 are capable of commanding the switching to a redundant power supply network as a function of the switching logic outlined below.
The switching logic between the power supply networks R1, . . . , RN using control subsystem 14 implements a state machine including N+1 distinct states F(0), F(1), . . . , F(N), representative of the possible states of the power supply system 10, i.e.:

    
    
        a state F(0) corresponding to the selection of no energy source by the control subsystem 14,
        N states F(i), in which the corresponding power supply network Ri is selected as energy source, and the other power supply networks are then not used, i being an integer comprised between 1 and N.
    
    


The control subsystem 14 command the opening or closing of the corresponding controllable members Ti to ensure the passage from a state F(x) to a state F(y) as a function of the input voltages V1, . . . , VN, as well as the amount of energy E stored in the energy storage subsystem 18, for any integer x and y comprised between 0 and N and different from each other.
The operation and the switching logic of the control subsystem 14 will be described in more detail below.
Initially, the power supply system 10 is in the state F(0).
The power supply system 10 can then leave that state F(0) for a state F(i), i being an integer comprised between 1 and N, only if the condition Vi>Si is verified by at least one of the power supply networks Ri. If several power supply networks verify the previous condition, the selected power supply network Ri is that having the smallest index i.
If the value of the quantity of energy E becomes smaller than the smallest energy level EN, the control subsystem 14 command all of the controllable members T1, . . . , TN into the open position so as not to select any energy source, the power supply system 10 then returning to the state F(0).
This occurs in particular when the voltage Vi of the selected power supply network Ri does not verify the condition Vi>Si and no power supply network with a lower energy level itself verifies that condition. The energy storage subsystem 18 then deplete until the amount of energy E is smaller than the smallest energy level EN.
The selection of a power supply network Rj with an energy level Ej higher than the energy level Ei is then possible from the state F(0).
After switching from the state F(0) to a state F(s), s being an integer comprised between 1 and N, the passage to another state F(k), k being an integer comprised between 1 and N and different from s, is only allowed by the control subsystem 14 once the condition E=Emax is verified. In other words, after the switching from the selection of no energy source to a first power supply network RS, the control subsystem 14 can inhibit the switching toward a second power supply network Rk as long as the amount of energy E of the energy storage subsystem 18 has not reached the maximum storage capacity Emax.
This makes it possible to avoid deactivation of the priority power supply network when that network is strongly disrupted, for example when it has many outages in its input voltage. The control subsystem 14 then only command the switch to another power supply network R1, . . . , RN, when the successive power line disturbances have depleted the energy storage subsystem 18.
For a given power supply network Ri, the cumulative time of the power line disturbances that the power supply network can undergo without the control subsystem 14 commanding switching to another power supply network R1, . . . , RN is of the same order of magnitude as the transparency t(i).
The amount of time between the passage from the state F(0) to a state F(s) and the moment when the condition E=Emax is verified is called the startup of the power supply system 10.
To that end, the control subsystem 14 generate an ON state signal, which is validated once the amount of energy E has reached the maximum storage capacity Emax, and invalidated when the amount of energy E becomes lower than the smallest energy level EN. The logic condition associated with the generation of that state signal is then written:
ON=(ON+(E=Emax)) & (E>EN), the inverse logic condition being noted Not_ON hereafter.
After starting up the power supply system 10, i.e., when the ON state signal is validated, the control subsystem 14 can, during a outage of the input voltage Vl delivered by the selected power supply network Rl, command the passage from the corresponding state F(I) to a state F(z), I and z being integers respectively comprised between 1 and N−1 and between 2 and N, with I<z, if the following condition is verified.

E<El and Vz>Sz  (C1)

In other words, the control subsystem 14 can command the switch from a first power supply network Rl to a second associated power supply network Rz with a lower energy level Ez only if the amount of energy E is lower than the energy level El associated with the first power supply network Rl and if the second power supply network Rz has an input voltage Vz higher than the associated voltage threshold Sz.
Among all of the power supply networks Rw verifying the condition Vw>Sw, the power supply network Rz associated with a higher energy level Ez is then selected. Thus, if the power supply network Rl+1 associated with a directly lower energy level El+1 delivers an input voltage Vl+1 higher than the corresponding voltage threshold Sl+1, that power supply network Rl+1 is selected.
Furthermore, when the ON state signal is validated, the control subsystem 14 command the passage of the power supply system 10 from a state F(r) to a state F(m), where r and m are integers comprised between 1 and N and m<r, if the following condition is verified:

E=Emax and Vm>Sm  (C2)

In other words, the control subsystem 14 can command the switch from a first power supply network Rr to a second associated power supply network Rm with a higher energy level Em only if the amount of energy E of the energy storage subsystem 18 is equal to the maximum storage capacity Emax and if the input voltage Vm delivered by the second power supply network Rm is higher than the corresponding voltage threshold Sm.
Among all of the power supply networks Rx verifying the condition Vx>Sx, the power supply network Rm associated with a maximum energy level Em is then selected. Thus, if the power supply network R1 with a maximum energy level E1 from among all of the energy levels E1, . . . , EN delivers an input voltage higher than the corresponding voltage threshold S1, that power supply network R1 is selected.
The two switching conditions C1 and C2 pertaining both to the availability of the power supply networks R1, . . . , RN and the amount of energy E of the energy storage subsystem 18 make it possible to eliminate untimely switching between the power supply networks R1, . . . , RN.
Condition C1 makes it possible to eliminate untimely switching during power line disturbances occurring on the input voltage of the selected network Ri.
Condition C2 makes it possible to eliminate untimely switching during the reappearance of a priority power supply network relative to the selected power supply network Ri. These two conditions apply on any power supply network R1, . . . , RN.
This thereby makes it possible to decrease the number of switches between the power supply networks R1, . . . , RN and to avoid generating instabilities and disturbances of the power supply networks due to untimely switching, as well as to increase the lifetime of the members of the power supply system 10 according to the invention. In fact, in the state of the art, in the event of a large number of successive power line disturbances, the switches between networks are also very numerous, which causes significant variations in the consumed currents. This tends to cause instabilities of all of the equipment powered by the power supply network Ri.
Furthermore, the priority order between the power supply networks R1, . . . , RN and the duration of the power line disturbance having to be held by each network R1, RN can be configured through the choice of predetermined energy level E1, . . . , EN and transparency t(1), . . . , t(N) values. This in particular makes it possible to adapt the selection logic of at most one energy source to various constraints, such as flight constraints, hardware configuration constraints, etc.
In the example embodiment of FIG. 3, illustrated in the case where N is equal to 2, the control subsystem 14 can command:

    
    
        the passage from the state F(0) to the state F(1) if (V1>S1), (arrow 20),
        the passage from the state F(0) to the state F(2) if (V1<S1) & (V2>S2), (arrow 22),
        the passage from the state F(1) to the state F(2) if
        (V1<S1) & (V2>S2) & ON & (E<E1), (arrow 24),
        the passage from the state F(2) to the state F(1) if (V1>S1) & (E=Emax) & ON, (arrow 26),
        the passage from the state F(1) to the state F(0) if (V1<S1) & Not_ON, (arrow 28), and
        the passage from the state F(2) to the state F(0) if (V2<S2) & Not_ON, (arrow 30).
    
    


FIG. 4 illustrates a second embodiment of the power supply system 10 for which the elements similar to the first embodiment previously described are identified using identical references, and are not described again.
According to the second embodiment, the control subsystem 14 can detect and prevent the propagation to other power supply networks of failures of the controllable members T1, . . . , TN or the unidirectional diodes D1, . . . , DN by selecting at most one energy source as a function of the N input voltages V1, . . . , VN, the storage voltage Ve, the intermediate voltages U1, . . . , UN and the selection voltage USEL.
When a given power supply network Ri is selected, with i being an integer comprised between 1 and N, the control subsystem 14 diagnose a failure of the associated controllable member Ti by measuring the voltage USEL.
If the voltage USEL is positive, then the controllable member Ti is in the operating state.
If the voltage USEL is zero, then the controllable member Ti comprises at least one no-load circuit component, and the power supply network Ri therefore cannot be used to power the power supply system 10. The corresponding power supply network Ri is then excluded from the set of power supply networks that can be selected by the control subsystem 14.
This is for example done through a modification of the selection logic of the control subsystem 14. The state F(i) corresponding to the selection of the power supply network Ri whereof the corresponding controllable member Ti is faulty can then be eliminated from the state machine, as shown in FIG. 5, so as to prohibit switching toward the selection of that network.
Complementarily, when a given power supply network Rj is selected, with j being an integer comprised between 1 and N, the control subsystem 14 diagnose the proper operation of the unidirectional diodes D1, . . . , , DN by measuring the intermediate voltages U1, . . . , UN.
Thus, for any j that is an integer comprised between 1 and N:

    
    
        if the voltage Uj is zero 0, then the unidirectional diode Dj is in the operating state; and
        if Uj is positive, then the unidirectional diode Dj may be short-circuited, in which case the power supply networks R1, . . . , RN are no longer electrically insulated from each other.
    
    


Only the power supply network Rj whereof the unidirectional diode Dj is faulty can then be selected by the control subsystem 14, the other power supply networks having to be kept isolated from that network. If the availability of the power supply system 10 is not a predominant criterion, the control subsystem 14 command the selection of no energy source, as will be seen below.
The operation of the power supply system 10 according to the second embodiment of the invention will now be described in more detail.
In addition to the N−1 aforementioned states of the power supply system 10, an additional state FS (Fail Safe) is defined, in which all of the controllable members T1, . . . , TN are commanded into the open position, their command into the closed position also being inhibited.
The control subsystem 14 are adapted to inhibit the passage of the power supply system from the state FS to any state F(e), e being an integer comprised between 0 and N, unlike in the preceding with respect to the state F(0) capable of switching to another state.
In the second embodiment, the control subsystem 14 can command:

    
    
        the switching from the state F(0) to the state FS if an integer q exists comprised between 1 and N such that Uq≠0, i.e., if one of the intermediate voltages U1, . . . , UN is non-zero, and
        the switching from a given state F(h), h being an integer comprised between 1 and N, to the state FS if an integer g exists comprised between 1 and N and different from h such that Ug≠0 or if the conditions USEL=0 et Vh>Sh are verified, i.e. if at least one controllable member Tg other than the controllable member Th associated with the selected power supply network Rh has a non-zero intermediate voltage Ug or if the selection voltage USEL is zero while the input voltage Vh of the power supply network Rh is higher than the associated voltage threshold Sh.
    
    


In the example embodiment of FIG. 5, illustrating the case where N is equal to 2, the control subsystem 14 command, in addition to the passages between the states previously described in light of FIG. 3, the following passages:

    
    
        the passage from the state F(0) to the state FS if (U1≠0) or (U2≠0), (arrow 32);
        the passage from the state F(1) to the state FS if (U2≠0) or (USEL=0) and (V1>S1), (arrow 34); and
        the passage from the state F(2) to the state FS if (U1≠0) or (USEL=0) and (V2>S2) (arrow 36).
    
    


The switching logic between the power supply networks implemented in this embodiment in particular makes it possible to reinforce the electrical isolation between the power supply networks R1, . . . , RN, in particular in the event of breakdowns of members of the power supply system 10. This embodiment is therefore preferably used to increase the security of the power supply system 10.
According to one alternative, not shown and advantageously implemented when the availability of the power supply system 10 is an important constraint, the control subsystem 14 command passage of the power supply system 10 to a state F(p), p being an integer comprised between 1 and N, if the condition Up≠0 is verified while the condition Uf=0 is verified for any integer f comprised between 1 and N and different from p.
This switching logic makes it possible to electrically isolate the power supply networks from a power supply network Ri whereof the corresponding unidirectional diode Di is potentially faulty while ensuring operation of the power supply system 10 in failsafe mode.
Furthermore, the control subsystem 14 inhibit the passage of the power supply system 10 toward any state F(x), x being an integer comprised between 1 and N, in which the conditions USEL=0 and Vx>Sx are verified.
FIG. 6 illustrates a third embodiment of the power supply system 10 for which the elements similar to the first embodiment previously described are identified using identical references, and are not described again.
According to the third embodiment, at least one controllable member Ti of the power supply system 10 comprises an energy converter including the unidirectional diode Dj. The converter is for example a rectifier.
FIG. 7 illustrates a fourth embodiment of the power supply system 10 for which the elements similar to the first embodiment previously described are identified using identical references, and are not described again.
According to the fourth embodiment, at least one unidirectional diode Di is arranged in parallel with a switch Ki, the or each diode Di being intrinsic or attached to the switch Ki. The control subsystem 14 can then command the switches Ki into the open or closed position.
FIG. 8 illustrates a fifth embodiment of the power supply system and for which the elements similar to the first embodiment previously described are identified using identical references, and are not described again.
According to the fifth embodiment, all of the controllable members T1, . . . , TN are converters capable of converting the corresponding input voltage V1, . . . , VN into the output voltage Vout of the power supply system 10. Associating a power converter with each power supply network R1, . . . , RN in particular makes it possible to limit the energy consumption on the non-selected power supply networks R1, . . . , RN.
The shared power supply line 15 forms an output network of the power supply system 10.
The control subsystem 14 can then command the power converters T1, . . . , TN both to select at most one energy source from among the N power supply networks R1, . . . , RN and to regulate the intermediate voltage Ui from the input voltage Vi, the output voltage Vout then being equal to the intermediate voltage Ui.
In this fifth embodiment, the energy converter 16 is dedicated to converting the electrical energy coming from and intended for the energy storage subsystem 18. It is then connected to the output network of the power supply system 10 and is serially mounted with the energy storage subsystem 18 between the shared power supply line 15 and an electrical ground 40.
In an alternative not shown, certain charges require the power supply system 10 to command the switching from the selected network Rv to a redundant network Rw, v and w being integers comprised between 1 and N, in the event of outage of the input voltage Vv for a duration longer than a defined delay duration ttemp. This makes it possible to have a transparency t(i) that is independent of the power delivered by the power supply network Rv and to measure the aging of the storage subsystem 18. In fact, the verification of the condition E=E(w) during a outage of the input voltage Vv for a duration shorter than the delay duration ttemp then indicates that the energy storage subsystem 18 have aged.
If the transparency t(v) of the power supply network Rv is greater than the delay duration ttemp the switching from the power supply network Rv to another power supply network is allowed for each outage of the input voltage Vv having a duration greater than the transparency t(v). However, in order to avoid the problems that arise during successive power line disturbances and resolved according to the invention by implementing energy levels Ei, this additional switching condition pertaining to the delay duration ttemp must account for the cumulative sum of the durations of the power line disturbances having taken place on the power supply network Rv, the switching between power supply networks being commanded by the control subsystem 14 in accordance with the first embodiment of the invention.
To that end, the cumulative sum of the durations of the power line disturbances experienced by the delay duration ttemp is stored by a configurable meter such that the stored cumulative sum is reset when the energy level E reaches Emax. In that case, the cumulative sum of all of the power line disturbances experienced by the delay duration ttemp is smaller than the transparency t(v).
One can thus see that the power supply system, in various embodiments, makes it possible to limit the number of switches between the networks. While various embodiments have been described, they are illustrative of the invention and not limiting since the claims define the scope of the invention.

## Claims

1. A power supply system configured to deliver a DC output voltage (Vout) and of being connected in input to N distinct power supply networks (R1, . . . , RN) each delivering an input voltage (V1, . . . , VN), N being an integer greater than or equal to 2, the system comprising:
N controllable energy transfer members (T1, . . . , TN), each configured to switch between an open position and a closed position and being connected to a corresponding power supply network (R1, . . . , RN);
a control subsystem for each of the controllable energy transfer members (T1, . . . , TN) configured to select one power supply network (R1, . . . , RN) from among the N power supply networks (R1, . . . , RN) by commanding the controllable energy transfer member (T1, . . . , TN) connected to the selected power supply system (R1, . . . , RN) into the closed position and commanding the N−1 other controllable power transfer member(s) into the open position (T1, . . . , TN), and
an energy storage subsystem configured to deliver a storage voltage (Ve),
wherein the power supply system further comprises an energy converter (16) connected to the output of the N controllable energy transfer members (T1, . . . , TN), the control subsystem being adapted to control the energy converter and the N controllable energy transfer members (T1, . . . , TN) to select at most one energy source from among the N power supply networks (R1, . . . , RN), as a function of the N input voltages (V1, . . . , VN) and the storage voltage (Ve).

2. The power supply system according to claim 1, wherein the energy storage subsystem has a maximum storage capacity (Emax), in that the power supply networks (R1, . . . , RN) are ordered by increasing energy levels (E1, . . . , EN), each energy level (E1, . . . , EN) being predetermined and associated with the corresponding power supply network (R1, . . . , RN) and having a positive value below the maximum storage capacity (Emax), and in that the control subsystem is adapted to select, as a priority, the power supply network (R1, . . . , RN) associated with the highest energy level (E1, . . . , EN).

3. The power supply system according to claim 2, wherein voltage thresholds (S1, . . . , SN) are respectively associated with the power supply networks (R1, . . . , RN), the control subsystem configured to controlling the switching from a first power supply network (R1, . . . , RN) to a second power supply network (R1, . . . , RN) only if the second power supply network (R1, . . . , RN) has an input voltage (V1, . . . , VN) higher than the corresponding voltage threshold (S1, . . . , SN).

4. The power supply system according to claim 2, wherein the difference between two successive energy levels (Eu−1, Eu) corresponds to the energy supplied by the energy storage subsystem to the energy converter during the outage, for a transparency duration (t(1), . . . , t(n)) unique to each power supply network (R1, . . . , RN), of the input voltage (Vu) of the power supply network (Ru) with the lowest associated energy level (Eu) of the two energy levels (Eu−1, Eu).

5. The power supply system according to claim 4, wherein the control subsystem is adapted to command the switch from a first power supply network (R1, . . . , RN), the transparency duration (t(1), . . . , t(n)) of which is longer than a predetermined delay period (ttemp), to a second power supply network (R1, . . . , RN) during a outage of the input voltage (V1, . . . , VN) of the first power supply network (R1, . . . , RN) for a duration longer than the delay period (ttemp).

6. The power supply system according to claim 3, wherein the storage voltage (Ve) is representative of a quantity of energy (E) of the energy storage subsystem, and in that the control subsystem can command the switch from a first power supply network (R1, . . . , RN) to a second power supply network (R1, . . . , RN) with a lower associated energy level (E1, . . . , EN), during a outage of the input voltage (V1, . . . , VN) of the first power supply network (R1, . . . , RN), only if the quantity of energy (E) of the energy storage subsystem is lower than the energy level (E1, . . . , EN) associated with the first power supply network (R1, . . . , RN).

7. The power supply system according to claim 3, wherein the control subsystem is adapted to command the switch from a first power supply network (R1, . . . , RN) to a second power supply network (R1, . . . , RN) with a higher energy level (E1, . . . , EN) only if the amount of energy (E) of the energy storage subsystem (18) is equal to the maximum storage capacity (Emax).

8. The power supply system according to claim 1, wherein the control subsystem is adapted to command the selection of no energy source by commanding all of the controllable energy transfer members (T1, . . . , TN) into the open position.

9. The power supply system according to claim 8, wherein the energy storage subsystem has a maximum storage capacity (Emax), the control subsystem being operable to inhibit the switch from a first power supply network (R1, . . . , RN), toward which switching was commanded from the selection of no energy source, to a second power supply network (R1, . . . , RN) as long as the quantity of energy (E) of the energy storage subsystem is not equal to the maximum storage capacity (Emax).

10. The power supply system according to claim 8, wherein it also comprises a shared power supply line having a selection voltage (USEL), in that the controllable energy transfer members (T1, . . . , TN) are connected to the shared power supply line, and in that the control subsystem is configured to command the energy converter and the N controllable energy transfer members (T1, . . . , TN) to select at most one energy source from among the N power supply networks (R1, . . . , RN), as a function of the N input voltages (V1, . . . , VN), of the storage voltage (Ve), of intermediate voltages (U1, . . . , UN) delivered by the controllable energy transfer members (T1, . . . , TN), and of the selection voltage (USEL).

11. The power supply system according to claim 10, wherein the control members are adapted to command the switch to a secured state (FS) of the power supply network in which the controllable energy transfer members (T1, . . . , TN) are all commanded into the open position, their command into the closed position being inhibited.

12. The power supply system according to claim 11, wherein the control subsystem is adapted to command the switch from the selection of no energy source to the secured state (FS) if at least one intermediate voltage (U1, . . . , UN) is non-zero.

13. The power supply system according to claim 11, wherein the voltage thresholds (S1, . . . , SN) are respectively associated with the power supply networks (R1, . . . , RN), the switching/selection subsystem being adapted to command the switch of a power supply network (R1, . . . , RN) to the secured state (FS) if at least one controllable energy transfer member (T1, . . . , TN) other than the controllable power transfer member (T1, . . . , TN) associated with the power supply network (R1, . . . , RN) has a non-zero intermediate voltage (U1, . . . , UN) or if the selection voltage (USEL) is zero whereas the input voltage (V1, . . . , VN) of the power supply network (R1, . . . , RN) is above the associated voltage threshold (S1, . . . , SN).

14. The power supply system according to claim 1, wherein it also comprises a shared power supply line to which the controllable energy transfer members are connected (T1, . . . , TN), and in that the power supply system comprises N unidirectional diodes (D1, . . . , DN) respectively connected between the output of the given controllable energy transfer member (T1, . . . , TN) and the shared power supply line.

15. A power supply system configured to deliver a DC output voltage (Vout) and of being connected in input to N distinct power supply networks (R1, . . . , RN) each delivering an input voltage (V1, . . . , VN), N being an integer greater than or equal to 2, the system comprising:
N controllable energy transfer members (T1, . . . , TN), each configured to switch between an open position and a closed position and being connected to a corresponding power supply network (R1, . . . , RN);
control means, for each of the controllable energy transfer members (T1, . . . , TN), for selecting one power supply network (R1, . . . , RN) from among the N power supply networks (R1, . . . , RN) by commanding the controllable energy transfer member (T1, . . . , TN) connected to the selected power supply system (R1, . . . , RN) into the closed position and commanding the N−1 other controllable power transfer member(s) into the open position (T1, . . . , TN), and
energy storage means for delivering a storage voltage (Ve),
wherein the power supply system further comprises an energy converter (16) connected to the output of the N controllable energy transfer members (T1, . . . , TN), the control subsystem being adapted to control the energy converter and the N controllable energy transfer members (T1, . . . , TN) to select at most one energy source from among the N power supply networks (R1, . . . , RN), as a function of the N input voltages (V1, . . . , VN) and the storage voltage (Ve).