CONTROL UNIT FOR CONTROLLING THE POWER OF AT LEAST ONE BATTERY, AIRCRAFT WITH THE CONTROL UNIT AND ASSOCIATED CONTROL METHOD

Description

Technical field

[0001] The technical field of the invention is the electrical protection of aircraft power supply networks, and more particularly, the protection of high voltage DC power supply networks. Previous techniques

[0002] Electrical systems on board an aircraft typically include either a combination of an AC (115Vac or 230Vac) and a low-voltage DC (28Vdc) system, or a single DC (28Vdc) system. Examples of such systems are US2017285109 and US2019097453.

[0003] Aircraft operating via an AC network have a total on-board electrical power of between 50 and 500 kW (or even 1 MW) while purely low voltage DC networks (acronym BT) have more limited on-board powers of less than 100 kW.

[0004] Currently, there is no high-voltage DC network for aircraft. Therefore, there are no components capable of operating at 800 VDC and at power outputs of around 100 to 250 kW. Such networks would be advantageous for electrically powered aircraft.

[0005] The evolution towards a high-voltage continuous power supply network on the one hand and towards electrical energy sources consisting of batteries on the other hand, makes traditional protection solutions (mainly type I 2< t figure 1 ) unusable. Indeed, the transient current profiles are different in high direct voltage from those encountered in high alternating voltage. The energy levels and associated dynamics are completely different from those encountered in high alternating voltage networks.

[0006] The type I 2< t protection and selectivity action strategy, which is well suited to a rotating machine, is then no longer relevant. In addition, the sizing of this protection for AC networks is carried out according to the conductors of the supply network and the winding of the rotating machine. Capacitive sources make such sizing of type I 2< t protection unsuitable.

[0007] Capacitive sources, such as high-power batteries, can be subject to incidents unknown to rotating machinery, resulting in thermal runaway or very high-power short-circuit currents.

[0008] When the battery heats up excessively beyond a certain temperature, the battery is subject to thermal runaway, which can eventually cause overpressure and gas release. This heating can be caused by excessive current, when the battery is overcharged or suffers a short circuit.

[0009] Short-circuit currents developed by such batteries (particularly Li-Ion technology) can reach values ​​of several thousand amperes following a very rapid rise shortly after the short circuit is established. It is then difficult to interrupt such high currents with a very short rise time, in a reasonable size and mass compatible with an aircraft.

[0010] The invention thus aims to address the deficiencies of the state of the art and in particular the limitations identified above, concerning the protection of high voltage DC electrical networks for aircraft.

[0011] The following documents are known from the state of the prior art.

[0012] Document EP 3 703 220 A1 describes the regulation of the voltage delivered by an active rectifier in order to be able to connect it to a battery.

[0013] Document EP 3 588 729 B1, document EP 2 980 946 B1 and document FR 3 050 882 describe conventional electrical networks, which aim to supply the on-board network of an aircraft.

[0014] Document WO 2020 / 174165 A1 and document FR 3 098 663 describe the architecture of an electric propulsion system, but remain silent on the protection and distribution boxes.

[0015] Document EP 3 683 911 A1 describes a fault protection method applied to interconnected high voltage direct current (HVDC) networks.

[0016] None of these documents resolve the technical problem identified above. Statement of the invention

[0017] The invention is defined by the independent claims and relates to a battery power control unit comprising at least two incoming connections carrying a direct voltage and two outgoing connections delivering a direct voltage, a first incoming connection being connected to a first current sensor and to a high-voltage power bar via a protection member, the high-voltage power bar being connected to a first outgoing connection via a first controlled fuse and a second current sensor and to a second outgoing connection via a second controlled fuse and a third current sensor, the control unit further comprising a control means configured to switch at least one of the protection member, the first controlled fuse and the second controlled fuse as a function of the measurements received from the first current sensor,of the second current sensor or the third current sensor so as to isolate an electrical fault in the control unit, at least one of the incoming connections or at least one of the outgoing connections.,

[0018] The control unit may comprise a first contactor and a second incoming connection, the first contactor being connected on the one hand to the first current sensor and on the other hand to the protection member, the second incoming connection being connected to the first contactor via a second contactor connected to the control means.

[0019] The control unit may include a third incoming connection connected to a third contactor via a fourth current sensor, the third contactor being connected to the high voltage power bar, the third contactor and the fourth current sensor being connected to the control means.

[0020] A secondary power bar can be arranged between a current sensor and the corresponding contactor or the corresponding controlled fuse.

[0021] The invention also relates to an aircraft provided with a battery and two electric motors, comprising a battery power control unit as described above, in which the first incoming connection is connected to the battery, the first outgoing connection being connected to the first electric motor, the second outgoing connection being connected to the second electric motor.

[0022] The aircraft may include an emergency power supply and / or be connected to a stationary charging means, wherein the second incoming connection is connected to the stationary charging means and the third incoming connection is connected to the emergency power supply.

[0023] The aircraft may include two power control units of a battery connected in parallel via their third incoming connections.

[0024] The aircraft may comprise two battery power control units connected in parallel by their second incoming connection, each battery power control unit comprising a link between their high voltage power bar and the first outgoing connection and the second outgoing connection of the other battery power control unit, each link being provided with a second protection member controlled by the control means.

[0025] The invention finally relates to a method for controlling an electrical power control unit arranged in an aircraft as described above, the control method comprising the following steps: to power the electric motor via the battery, the first contactor is controlled so that it is made conductive while the second contactor and the third contactor are controlled so that they are made non-conductive, to power the electric motor via the emergency power supply, the third contactor is controlled so that it is made conductive while the first contactor and the second contactor are controlled so that they are made non-conductive, and to charge the battery via the auxiliary power group, the second contactor is controlled so that it is made conductive while the first contactor and the third contactor are controlled so that they are made non-conductive.

[0026] When a fault is detected in the power supply of an electric motor or group of electric motors supplied by one of the outgoing connections via the protection device, the following steps can be carried out: the opening of the protective device is commanded in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery, a fault message is sent from the protective device to the control means, an opening command is sent from the control means to the first contactor in order to physically isolate the battery, the location of the fault is determined based on the measurements of the first current sensor, the second current sensor, the third current sensor and the fourth current sensor via the control means, an activation command is sent from the control means to the first controlled fuse, after the first controlled fuse has tripped,a closing command is issued from the control means to the first contactor and to the protection device in order to restore power to the other electric motor.

[0027] When a fault is detected on the high voltage power bar, the following steps can be performed: the opening of the protective member is commanded in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery, a fault message is sent from the protective member to the control means, an opening command is sent from the control means to the first contactor in order to physically isolate the battery, the measurements of the first current sensor, the second current sensor, the third current sensor and the fourth current sensor are compared via the control means, and a power supply fault information message is sent according to the result of the comparison.

[0028] When a fault is detected on the battery via the control means based on the measurements of the first current sensor and / or the protection device, the following steps can be carried out: an opening command is issued from the control means to the first contactor in order to physically isolate the battery, an opening command is issued from the control means to the protection member, a closing command is issued from the control means to the third contactor in order to restore the power supply to the electric motors, a pre-charging sequence is initiated on the emergency power supply in order to charge the capacities of the electric motors, and once the capacities are charged, the main line is activated.

[0029] When a fault is detected on the emergency power supply via the control means based on the measurements of the fourth current sensor, the following steps can be carried out: an opening command is issued from the control means to the third contactor in order to physically isolate the emergency power supply, and information on a power supply redundancy fault is issued from the control means. Brief description of the drawings

[0030] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which: there figure 1 illustrates the main elements of a battery power control unit according to the invention, the figure 2 illustrates the main steps of a method of controlling such a control unit, and the figure 3 illustrates the main elements of an alternative embodiment of a battery power control unit according to the invention. Detailed description

[0031] In order to solve the technical problem, a battery power control unit (BPMU) is proposed. The battery power control unit (BPMU) is referenced 1 on the figure 1 .

[0032] The power control unit of a battery 1 comprises three incoming connections 2,3,4 carrying a direct voltage and two outgoing connections 5a,5b also delivering a direct voltage.

[0033] A first incoming connection 2 can be connected to a battery.

[0034] A second incoming connection 3 may be connected to a stationary charging means, such as an auxiliary power unit (APU).

[0035] A third incoming connection 4 can be connected to a backup power supply.

[0036] A first outgoing connection 5a can be connected to a first electric motor or group of electric motors.

[0037] A second outgoing 5b connection can be connected to a second electric motor or group of electric motors.

[0038] The first incoming connection 2 is connected to a first current sensor 2a itself connected to a first contactor 5. The output of the first contactor 5 is connected to a high-voltage power bar 8 via a protection device 2c SSPC (acronym for “Solid State Power Controller”). The protection device 2c is configured to limit the current flowing through its terminals and to allow precharging when power arrives. When the protection device closes, the potential difference (high-voltage battery upstream and zero voltage downstream) generates a current close to the short-circuit current levels. In order to avoid this, the protection device 2c is equipped with a current limitation allowing a gradual increase in voltage and thus avoiding the establishment of a short-circuit current.

[0039] The second incoming connection 3 is connected to a second contactor 6, itself connected to the input of the first contactor 5 in parallel with the first current sensor 2a.

[0040] The high-voltage power bar 8 is connected at the output to the first outgoing connection 5a to a first electric motor via a first controlled fuse 2b and a second sensor 2d and to the second outgoing connection 5b via a second controlled fuse 3b and a third sensor 3d.

[0041] The first controlled fuse 2b and the second controlled fuse 3b are used to isolate the first electric motor and the second electric motor respectively in the event of a distribution fault.

[0042] The third incoming connection 4 is connected to a fourth current sensor 4a which is itself connected to a third contactor 7. The output of the third contactor 7 is connected to the high voltage power bar 8.

[0043] The first current sensor 2a, the second current sensor 2d, the third current sensor 3d and the fourth current sensor 4a are capable of measuring the current flowing between their terminals.

[0044] The second current sensor 2d, the third current sensor 3d and the fourth current sensor 4a are additionally capable of detecting the formation of series and / or parallel electric arcs.

[0045] The battery power control unit 1 also comprises a control means 9 configured to control the first contactor 5, the second contactor 6 and the third contactor 7, the protection member 2c SSPC, the first controlled fuse 2b and the second controlled fuse 3b as a function of the measurements received from the current sensors 2a, 4a, 2d, 3d and the state of the protection member 2c SSPC.

[0046] In a particular embodiment, the power control unit of a BPMU battery comprises secondary power bars 2e, 2f, 2g, 2h at the output of the first sensor 2a, the second sensor 2d and at the input of the third sensor 3d and the fourth sensor 4a. These secondary power bars 2e, 2f, 2g, 2h make it possible to connect in parallel several powering elements (batteries, emergency power supplies) or several powered elements (several electric motors) by multiplying the different connections.

[0047] The main steps of the control method according to the invention will now be described, and are illustrated by the figure 2 .

[0048] To power the electric motor via the battery, during a first step 11, the first contactor 5 is made conductive while the second contactor 6 and the third contactor 7 are made non-conductive.

[0049] To power the electric motor via the emergency power supply, during a second step 12, the third contactor 7 is made conductive while the first contactor 5 and the second contactor 6 are made non-conductive.

[0050] To charge the battery by the auxiliary power unit, during a third step 13, the second contactor 6 is made conducting while the first contactor 5 and the third contactor 7 are made non-conducting.

[0051] The control method also includes steps when a fault occurs in the power supply to the electric motors, such as a short circuit or an overvoltage).

[0052] During a first sub-step, a fault is detected via the protection device 2c SSPC and the opening of the protection device 2c SSPC is commanded in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery. A fault message is sent from the protection device 2c SSPC to the control means 9.

[0053] During a second sub-step, an opening command is issued from the control means 9 to the first contactor 5 in order to physically isolate the battery.

[0054] In a third sub-step, the location of the fault is determined based on the measurements of the first current sensor 2a, the second current sensor 2d, the third current sensor 3d and the fourth current sensor 4a by means of the control means 9.

[0055] In a fourth sub-step, an activation command is issued from the control means 9 to the first controlled fuse 2b. The analysis and comparison of the currents via the current sensors 2d, 3d and 2a make it possible to identify the location of the fault causing a short circuit. The control means 9 then actuates the switching element closest to the fault.

[0056] During a fifth sub-step, after the first controlled fuse 2b has tripped, a closing command is sent from the control means 9 to the first contactor 5 and to the protection member 2c SSPC in order to restore the power supply to the other electric motor.

[0057] The control method also includes steps when a fault occurs, such as a short circuit or an overvoltage on the power bar 8.

[0058] During a first sub-step, a fault is detected via the protection device 2c SSPC and the opening of the protection device 2c SSPC is commanded in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery. A fault message is sent from the protection device 2c SSPC to the control means 9.

[0059] During a second sub-step, an opening command is issued from the control means 9 to the first contactor 5 in order to physically isolate the battery.

[0060] In a third sub-step, the measurements of the first current sensor 2a, the second current sensor 2d, the third current sensor 3d and the fourth current sensor 4a are compared via the control means 9, in order to determine the location of the fault. Since the comparison of the measurements does not make it possible to determine the location of the fault, it is considered that the fault is located at the power bar 8.

[0061] In a fourth sub-step, a power supply fault information message is sent.

[0062] The control method also includes steps when a fault occurs, such as a short circuit or overvoltage on the battery.

[0063] During a first sub-step, a fault on the battery is detected by means of the control means 9 as a function of the measurements of the first current sensor 2a and / or of the protection member 2c SSPC. Such an error is characterized, for example, by a zero current.

[0064] During a second sub-step, an opening command is issued from the control means 9 to the first contactor 5 in order to physically isolate the battery and an opening command is issued from the control means 9 to the protection member 2c SSPC.

[0065] During a third sub-step, a closing command is issued from the control means 9 to the third contactor 7 in order to restore power to the electric motors.

[0066] During a fourth sub-step, a pre-charge sequence is initiated on the emergency power supply in order to charge the capacities of the electric motors. Once the capacities are charged, the main line is activated. In order to guarantee the quality of the electrical network, capacities are placed at different locations in the power control unit of a battery (electric motor, at the output of the SSPC protection device 2c). In order to avoid a sudden connection of these capacities to the voltage of the emergency battery during the switching of the device 7, a pre-charge sequence (which limits the current flowing in the switching device 7) is activated and makes it possible to increase the voltage of said capacities in order to equalize the upstream and downstream voltages. Once the upstream and downstream voltages are equal, the pre-charge sequence is completed and the main line for supplying the necessary power to the motor is activated.

[0067] The control method also includes steps when a fault, such as a short circuit or overvoltage, occurs on the backup power supply.

[0068] During a first sub-step, a fault on the emergency power supply is detected by means of the control means 9 based on the measurements of the fourth current sensor 4a. Such an error is characterized, for example, by a zero current.

[0069] During a second sub-step, an opening command is issued from the control means 9 to the third contactor 7 in order to physically isolate the emergency power supply.

[0070] During a third sub-step, information about a power supply redundancy fault is transmitted from the control means 9.

[0071] The power control unit of a BPMU battery and the corresponding control method make it possible to detect, protect and isolate faults which may occur in the power control unit of a BPMU battery or in the periphery to prevent their propagation on the one hand and, on the other hand, to ensure continuity of operation of the power supply to the motor(s).

[0072] The selected detection and switching elements make it possible to protect against electrical faults without relying on conventional type I 2< t methods which do not allow effective protection of a network supplied by high DC voltage batteries.

[0073] In a particular embodiment, two BPMU battery power control units may be combined together via their backup power supply so as to increase the number of powered electric motors. More specifically, the backup power supply of a first BPMU battery power control unit 1a is connected to the backup power supply of a second BPMU battery power control unit 1b. In the event of a battery failure supplying one or the other of the BPMU battery power control units, power supply redundancy may be provided by the other BPMU battery power control unit.

[0074] In another embodiment illustrated by the figure 3, two BPMU battery power control units 1a, 1b are combined together via their emergency power supply so as to increase the number of powered electric motors. However, unlike the BPMU battery power control units according to the other embodiments, the emergency power supply of one BPMU battery power control unit 1a, 1b is connected downstream of the high-voltage bus 8, the emergency power supplies of one BPMU battery power control unit being directly connected to the electric motors powered by the other BPMU battery power control unit so as to be able to power them in the event of a fault. Each electric motor power supply is then provided with a second SSPC protection member 4c, 5c controlled by the control means 9.

[0075] Furthermore, the battery supplying each BPMU battery power control unit may be connected in parallel to each BPMU battery power control unit so as to be able to contribute to the power supply of the electric motors in the event of an internal fault of a BPMU battery power control unit.

Claims

1. Aircraft provided with a battery and two electric motors, comprising a battery power control unit (1) comprising at least two incoming connections (2, 3) carrying a DC voltage and two outgoing connections (5a, 5b) delivering a DC voltage, a first incoming connection (2) being connected to a first current sensor (2a) and to a high-voltage busbar (8) via a protection member (2c), the high-voltage busbar being connected to a first outgoing connection (5a) via a first controlled fuse (2b) and a second current sensor (2d), and to a second outgoing connection (5b) via a second controlled fuse (3b) and a third current sensor (3d), the first incoming connection (2) being connected to the battery (1), the first outgoing connection (5a) being connected to a first electric motor, the second outgoing connection (5b) being connected to a second electric motor, the control unit further comprising a control means (9) designed to switch at least one out of the protection member (2c), the first controlled fuse (2b) and the second controlled fuse (3b) based on measurements received from the first current sensor (2a), the second current sensor (2d) or the third current sensor (3d) so as to isolate an electrical fault in the control unit, at least one of the incoming connections or at least one of the outgoing connections, the control unit comprising a first contactor (5) connected on the one hand to the first current sensor (2a) and on the other hand to the protection member (2c), the second incoming connection (3) being connected to the first contactor (5) via a second contactor (6) connected to the control means (9), the control unit comprising a third incoming connection (4) connected to a third contactor (7) via a fourth current sensor (4a), the third contactor (7) being connected to the high-voltage busbar (8), the third contactor (7) and the fourth current sensor (4a) being connected to the control means (9).

2. Aircraft according to Claim 1, wherein the control unit comprises a secondary busbar (2e, 2f, 2g, 2h) arranged between a current sensor (2a, 4a, 2d, 3d) and the corresponding contactor (5, 6) or the corresponding controlled fuse (2b, 3b).

3. Aircraft according to either one of Claims 1 or 2, comprising an emergency power supply and / or being connected to a stationary recharging means, wherein the second incoming connection (3) is connected to the stationary recharging means and the third incoming connection (4) is connected to the emergency power supply.

4. Aircraft according to Claim 3, comprising two battery power control units (1a, 1b) connected in parallel via their third incoming connections (4).

5. Aircraft according to Claim 3, comprising two battery power control units (1a, 1b) connected in parallel by their second incoming connection (3), each battery power control unit (1a, 1b) comprising a link between their high-voltage busbar (8) and the first outgoing connection and the second outgoing connection of the other battery power control unit (1b, 1a), each link being provided with a second protection member (4c, 5c) controlled by the control means (9).

6. Control method for an electrical power control unit (1) arranged in an aircraft according to one of Claims 1 to 5, the control method comprising the following steps: • to power the electric motor via the battery, the first contactor (5) is controlled so that it is made conductive while the second contactor (6) and the third contactor (7) are controlled so that they are made non-conductive, • to power the electric motor via the emergency power supply, the third contactor (7) is controlled so that it is made conductive while the first contactor (5) and the second contactor (6) are controlled so that they are made non-conductive, and • to charge the battery via the auxiliary power unit, the second contactor (6) is controlled so that it is made conductive while the first contactor (5) and the third contactor (7) are controlled so that they are made non-conductive.

7. Control method according to Claim 6, wherein, when a fault is detected in the power supply to an electric motor or group of electric motors supplied by one of the outgoing connections (5a, 5b) via the protection member (2c), the following steps are carried out: • the protection member (2c) is commanded to open in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery, • a fault message is sent from the protection member (2c) to the control means (9), • an opening command is sent from the control means (9) to the first contactor (5) in order to physically isolate the battery, • the location of the fault is determined based on measurements from the first current sensor (2a), the second current sensor (2d), the third current sensor (3d) and the fourth current sensor (4a) via the control means (9), • an activation command is sent from the control means (9) to the first controlled fuse (2b), • after the first controlled fuse (2b) has tripped, a close command is sent from the control means (9) to the first contactor (5) and to the protection member (2c) in order to restore power to the other electric motor.

8. Control method according to either one of Claims 6 or 7, wherein, when a fault is detected in the high-voltage busbar (8), the following steps are carried out: • the protection member (2c) is commanded to open in order to interrupt the current flowing from the battery, prevent the establishment of a short-circuit current and avoid thermal runaway of the battery, • a fault message is sent from the protection member (2c) to the control means (9), • an opening command is sent from the control means (9) to the first contactor (5) in order to physically isolate the battery, • the measurements are compared from the first current sensor (2a), the second current sensor (2d), the third current sensor (3d) and the fourth current sensor (4a) via the control means (9), and • a power supply fault information message is sent depending on the result of the comparison.

9. Control method according to one of Claims 6 to 8, wherein, when a fault is detected in the battery via the control means (9) based on the measurements from the first current sensor (2a) and / or the protection member (2c), the following steps are carried out: • an opening command is sent from the control means (9) to the first contactor (5) in order to physically isolate the battery, • an opening command is sent from the control means (9) to the protection member (2c), • a close command is sent from the control means (9) to the third contactor (7) in order to restore power to the electric motors, • a pre-charge sequence is initiated on the emergency power supply in order to charge the capacitors of the electric motors, and • once the capacitors have been charged, the main line is activated.

10. Control method according to one of Claims 6 to 9, wherein, when a fault is detected in the emergency power supply via the control means (9) based on the measurements from the fourth current sensor (4a), the following steps are carried out: • an opening command is sent from the control means (9) to the third contactor (7) in order to physically isolate the emergency power supply, and • a power supply redundancy fault notification is sent from the control means (9).