Capacity device for an aircraft electrical generation system and associated method

Abstract

A capacitor device (1) for an aircraft electrical generation system (S), the electrical generation system (1) comprising at least one electrical machine (M) configured to generate alternating current, at least one converter (C) for converting the alternating current from the electrical machine (M) and supplying a distribution current (Idc) to a continuously powered electrical distribution unit (EDU) of the aircraft, the capacitor device (1) being configured to be mounted in parallel with the converter (C) and to smooth the distribution current (Idc), the capacitor device (1) comprising two terminals and a plurality of capacitor elements mounted in parallel, the capacitor device (1) comprising at least one current sensor (2) configured to measure an elementary distribution current (Idce) flowing through a capacitor element. Abstract figure: Figure 5

Description

Title of the invention: Capacitor device for an aircraft electrical generation system and associated method. Technical field

[0001] The present invention relates to a capacity device for an electrical generation system for an aircraft.

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft and to those already in operation, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] This sustained research and development work focuses in particular on new generations of hybrid thermal and electric aircraft engines. The Applicant's objective is, in particular, to develop aircraft incorporating a high-power electrical generation system. This would increase the proportion of electrical equipment on board in order to reduce fuel consumption.

[0005] With reference to [Fig. 1], an aircraft AERO includes at least one aircraft turbomachine T comprising at least one shaft A (here a low-pressure shaft and a high-pressure shaft) configured to be driven in rotation and at least one continuously powered electrical distribution unit (EDU) connected to an aircraft electrical network (REA) or to electrical loads LOAD, for example, propulsion motors. The aircraft AERO includes at least one electrical generation system S100 to power the electrical distribution unit (EDU) by drawing mechanical energy from one or more shafts A.

[0006] With reference to [Fig. 2], the electrical generation system S100 comprises at least one electrical machine M connected to a shaft A of the turbomachine T. The system The electrical generation unit S100 includes at least one converter C, in particular an inverter associated with the electrical machine M. The electrical machine M generates an alternating current which is then rectified by the converter C to provide a distribution current Idc to the electrical distribution unit EDU which has a distribution voltage Vdc.

[0007] This example presents an application related to electrical generation, but the invention applies more generally to the field of hybridization in which an electric machine M performs, on the one hand, a generator function to extract mechanical power from a shaft A and, on the other hand, a motor function to inject mechanical power onto said shaft A. For a motor function, each converter C can also convert the distribution voltage Vdc to supply alternating current to the electric machine M in order to inject power.

[0008] In a known manner, a converter C comprises a plurality of switches TR, in particular power transistors, especially of the MOSFET type, which allow modification of the electrical power generated and the electrical power taken from the electrical machine M on the shaft A. In a known manner, the converter C is controlled by a control information, in particular, of the PWM type.

[0009] With further reference to [Fig. 2], the S100 power generation system includes a 100 capacitance device, known to those skilled in the art as a "DC Link" or capacitor bank, which is connected in parallel with the converter C. As is known, the 100 capacitance device absorbs the ripple in the distribution current Idc. This results in a power distribution unit (EDU) with a smooth distribution voltage Vdc. This prevents the distribution voltage Vdc from exhibiting large ripples.

[0010] With reference to [Fig. 3], a capacitance device 100 comprises, as is known, two terminals B1, B2 and a plurality of capacitance elements lOOi, also called coils, which are electrically connected in parallel. In this example, a capacitance element lOOi equivalently comprises a capacitance 111, a resistance 112, and an inductance 113. In practice, one or more capacitance elements lOOi may become damaged over time, which affects the performance of the capacitance device 100.

[0011] To monitor a fault in one or more capacitance elements lOOi, it is known to monitor the distribution voltage VDC and measure the amplitude of its ripple in order to determine the number of capacitance elements lOOi still active. If one or more capacitance elements lOOi are inactive, the capacitance value of the capacitance device 100 is reduced and the ripple of the distribution voltage Vdc increases.

[0012] To detect the number of inactive capacitance elements lOOi, it has been proposed to measure the effective (RMS) value of the distribution voltage Vdc but also The electrical resistance and temperature of the capacitance device 100 are measured and compared to predetermined expected values. If one or more capacitance elements 100i are inactive, the resistance and temperature increase in the capacitance device 100. In practice, accurately measuring the distribution voltage Vdc, electrical resistance, and temperature is difficult, making it challenging to determine if one or more capacitance elements 100i are inactive.

[0013] Furthermore, if one or more capacitance elements lOOi are inactive, the temperature of the capacitance device 100 may exceed the maximum permissible temperature for operating points of the electrical generation system S100. This can lead to critical faults in the electrical generation system S100. It is therefore desirable to detect early whether one or more capacitance elements lOOi are inactive in a capacitance device 100.

[0014] The invention thus aims to eliminate at least some of these drawbacks. PRESENTATION OF THE INVENTION

[0015] The invention relates to a capacitance device for an aircraft electrical generation system, the electrical generation system comprising at least one electrical machine configured to generate alternating current, at least one converter to convert the alternating current from the electrical machine and provide a distribution current to a continuous power supply electrical distribution unit of an aircraft, the capacitance device being configured to be mounted in parallel with the converter and to smooth the distribution current, the capacitance device comprising two terminals and a plurality of capacitance elements mounted in parallel.

[0016] The capacitance device is notable in that it includes at least one current sensor configured to measure an elementary distribution current flowing in a capacitance element.

[0017] Advantageously, the elementary distribution current is measured directly, which provides significant accuracy compared to measuring distribution voltage, resistance, or temperature. This allows for the precise determination of the number of inactive capacitor elements. The capacitor device can thus be effectively tested, protecting the power generation system.

[0018] In one aspect, the current sensor is of the Rogowski type. Such a current sensor has high accuracy. Furthermore, such a current sensor allows for the precise measurement of current variations and is therefore suitable for the application. Such a current sensor also has a large bandwidth and does not generate losses compared to a shunt. Such a current sensor also exhibits The advantage is that it doesn't significantly alter the mechatronic design. This avoids unbalancing the currents in the capacitance device, thus maintaining optimal performance. Furthermore, such a current sensor has a very low volume / mass impact.

[0019] According to one aspect, the current sensor is integrated into the capacitor device, in particular, into a resin. This makes it possible to obtain a capacitor device that is robust over time, particularly with regard to the constraints of the aeronautical environment.

[0020] Also presented is an aircraft electrical generation system, the aircraft comprising at least one aircraft turbomachine comprising at least one shaft configured to be driven in rotation, the electrical generation system comprising: • at least one electrical machine configured to generate alternating current by drawing mechanical energy from the shaft, • at least one converter to convert the alternating current from the electrical machine and provide a distribution current to a continuous-power electrical distribution unit of an aircraft, • at least one capacitance device, as previously described, mounted in parallel with the converter to smooth the distribution current.

[0021] Also presented is an aircraft comprising at least one aircraft turbomachine comprising at least one shaft configured to be driven in rotation, at least one continuously supplied electrical distribution unit and at least one electrical generation system, as previously presented, to supply the electrical distribution unit by taking mechanical energy from the shaft.

[0022] A method for controlling a capacitance device of an electrical generation system, as previously described, is also presented, the method comprising steps consisting of: • Supply a test distribution current to the capacitance device, the distribution current being distributed across the active capacitance element(s) connected in parallel, • Measure an elementary distribution current flowing through the capacitance element associated with the current sensor and • Issue a fault information if the elementary distribution current is greater than a determined current threshold.

[0023] Thus, it is possible to practically detect whether one or more capacitor elements are inactive in order to protect the generation system. Any increase in the elementary distribution current due to the loss of a capacitor element can be precisely determined.

[0024] According to one aspect, the capacitance device being configured to receive a maximum distribution current Idc_max, the test distribution current Idc_test is defined according to the following formula: 0.9*Idc_max <Idc_test < Idc_max. Selon un aspect, le courant de distribution test est égal au courant de distribution maximal. Un courant de distribution test de forte valeur permet de faciliter la détection par un capteur de courant. Toute augmentation liée à un défaut peut être aisément détectée avec un capteur de courant.

[0025] According to one aspect, the capacitance device being configured to receive a maximum distribution current Idc_max, the capacitance device having a number N of capacitance elements Idc_max, the current threshold determined is defined by the following formula: Sl= Idc_max / N. The current threshold is thus determined with respect to nominal operation when all the capacitance elements are active.

[0026] According to one aspect, a current having a direct component and a quadrature component according to the Park transform, the test distribution current has a quadrature component of zero value. This avoids any torque injection into the electrical machine during the test while having a high distribution current value to facilitate its detection.

[0027] According to one aspect, the control process comprises steps consisting of: • Determine the number of active capacitor elements in the capacitor device from the elementary distribution current, • Determine a maximum safe distribution current from the number of active capacity elements and • Control the electrical generation system by limiting the distribution current to the maximum safe distribution current.

[0028] Advantageously, the electrical generation system is controlled in a degraded mode to avoid any operating point that could damage the capacitor device. Safety and service life are improved.

[0029] According to one aspect, the method includes a step of determining the number of active capacitance elements of the capacitance device from the elementary distribution current and a predetermined database associating a number of active capacitance elements with a value of elementary distribution current. This allows for a quick and convenient determination.

[0030] According to one aspect, the method includes a step of emitting a fault information from the capacitance element associated with the current sensor if the elementary distribution current is zero. The fault is located, thus enabling practical maintenance.

[0031] The invention also relates to a computer program-type product, comprising at least one sequence of instructions stored and readable by a processor and which, once read by this processor, causes the steps of the process to be carried out as presented previously. Preferably, these steps are implemented by the computer.

[0032] The invention further relates to a computer-readable medium containing the computer program-type product as described above. PRESENTATION OF FIGURES

[0033] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0034] Fig. 1 is a schematic representation of an aircraft with an electrical generation system according to the prior art.

[0035] Fig. 2 is a schematic representation of an electrical generation system according to the prior art.

[0036] Fig. 3 is a schematic representation of a capacity device according to the prior art.

[0037] Fig. 4 is a schematic representation of an aircraft with an electrical generation system according to the invention.

[0038] Fig. 5 is a schematic representation of an electrical generation system according to the invention.

[0039] Fig. 6 is a schematic representation of a capacitance device according to the invention with a current sensor.

[0040] Fig. 7 is another schematic representation of a capacitance device with a current sensor.

[0041] Fig. 8 is a schematic representation of an example of the implementation of a control method.

[0042] Fig. 9 is a schematic representation of the evolution of the elementary distribution current as a function of the number of inactive capacitance elements.

[0043] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0044] With reference to [Fig. 4], an aircraft AERO is shown comprising at least one aircraft turbomachine T including at least one shaft A (here a low-pressure shaft and a high-pressure shaft) configured to be driven in rotation and at least one continuously supplied electrical distribution unit (EDU) connected to an aircraft electrical network (REA) or to electrical loads LOAD, for example, propulsion motors. The aircraft AERO includes at least one generation system electrical S to power the electrical distribution unit EDU by drawing mechanical energy from one or more shafts A.

[0045] With reference to [Fig.5], the electrical generation system S comprises at least one electrical machine M configured to generate alternating current by taking mechanical energy from the shaft A, at least one converter C to convert the alternating current from the electrical machine M and provide a distribution current Idc to a continuously powered electrical distribution unit EDU of an aircraft, the electrical distribution unit EDU having a distribution voltage Vdc.

[0046] This example presents an application related to electrical generation, but the invention applies more generally to the field of hybridization in which an electric machine M performs, on the one hand, a generator function to extract mechanical power from a shaft A and, on the other hand, a motor function to inject mechanical power onto said shaft A. For a motor function, each converter C can also convert the distribution voltage Vdc to supply alternating current to the electric machine M in order to inject power.

[0047] In a known manner, a converter C comprises a plurality of switches TR, in particular power transistors, especially of the MOSFET type, which allow modification of the electrical power generated and the electrical power taken from the electrical machine M on the shaft A. In a known manner, the converter C is controlled by a control information, in particular, of the PWM type.

[0048] The electrical generation system S includes at least one capacitance device 1 mounted in parallel with the converter C to smooth the distribution voltage Vdc. The capacitance device 1 is mounted between the converter C and the electrical distribution unit EDU as illustrated in [Fig. 5].

[0049] With reference to [Fig. 6], the capacitance device 1, known to those skilled in the art as a "DC Link" or capacitance bank, comprises two terminals B1, B2 and a plurality of capacitance elements li, also called coils, connected in parallel. In this example, a capacitance element li equivalently comprises a capacitor 11, a resistor 12, and an inductor 13. In this example, the capacitance device 1 has a number N of capacitance elements li, of which NI are active and N2 are inactive (N = N1 + N2).

[0050] The capacitance device 1 is notable in that it includes at least one current sensor 2 configured to measure an elementary distribution current Idce flowing in a capacitance element li. Preferably, the capacitance device 1 comprises a single current sensor 2, thereby reducing cost and complexity. It is nevertheless understood that several capacitance elements li could be equipped with a current sensor 2.

[0051] Preferably, the current sensor 2 is of the Rogowski type. In particular, the current sensor 2 comprises a printed circuit board including a Rogowski probe, for example, under the commercial reference TIDA-01063.

[0052] According to a preferred aspect, with reference to [Fig. 7], the current sensor 2 is integrated into the capacitance device 1. In this example, the current sensor 2 comprises a functional element 20 mounted on a capacitance element li and at least one communication cable 21 configured to be connected to a computer 3 ([Fig. 5]) in order to measure the elementary distribution current Idce flowing in said capacitance element li and to output fault information DEF or a command to the power generation system S, in particular a PWM command to control the converter C and adapt the distribution current Idc. The functional element 20 is in the form of a printed circuit board comprising a plurality of inductors for measuring the current while limiting losses. This advantageously allows for protection within a resin.

[0053] During operation, as illustrated in [Fig. 6], the distribution current Idc is divided equally among the NI active capacitance elements li. Thus, each active capacitance element li carries the same elementary distribution current Idce. The greater the number N2 of inactive capacitance elements li, the higher the elementary current Idce. [Fig. 9] illustrates the evolution of the elementary distribution current Idce as a function of the number N2 of inactive capacitance elements li.

[0054] In practice, the loss of a single capacitance element li induces a small increase in the elementary distribution current Idce on the other capacitance elements li, for example, on the order of 4 mArms. A Rogowski current sensor 2 has sufficient accuracy to detect the loss of a single capacitance element li.

[0055] A method for controlling a device of capacity 1 in an electrical generation system S, as previously described, will be presented. Such a control method can, for example, be implemented during the start-up of the electrical generation system S or periodically.

[0056] In this implementation example, the capacitance device 1 is configured to receive a maximum distribution current Idc_max. Preferably, the maximum distribution current Idc_max is defined for the operating point of the power generation system S that imposes the highest distribution current Idc. For example, it is determined by the limits of the converter C.

[0057] With reference to [Fig. 8], the method includes a step of supplying El a test distribution current Idc_test to the capacitance device 1, the distribution current Idc being distributed in the active capacitance element(s) li mounted in parallel. Preferably, the distribution current Idc is supplied by the converter C.

[0058] Preferably, the test distribution current Idc_test has a high value so as to generate an easily detectable increase in the elementary distribution current Idce. According to one aspect, the test distribution current Idc_test is defined by the following formula: 0.9*Idc_max <Idc_test < Idc_max. De manière préférée, le courant de distribution test Idc_est est égal au courant de distribution maximal Idc_max.

[0059] As is known, according to the Park transform, a current has a direct component and a quadrature component. In one aspect, the test distribution current Idc_test has a quadrature component of zero value. This advantageously avoids generating torque, thus improving safety while obtaining a high distribution current Ide.

[0060] Still referring to [Fig. 8], the control process comprises a step consisting of measuring E2 an elementary distribution current Idce flowing in the capacitance element li associated with the current sensor 2.

[0061] The method further includes a step of emitting a fault information DEF E3 if the elementary distribution current Idce exceeds a predetermined current threshold SI. The fault information DEF can take various forms, for example, an alert message, a computer message, a visual or audible alarm. According to a preferred aspect, as described below, a power limitation is triggered following the emission of the fault information DEF.

[0062] According to one aspect, the determined current threshold SI is defined as the maximum elementary distribution current Idc_max when all capacitance elements li are active. Preferably, the determined current threshold SI is defined by the following formula: Sl = Idc_max / N. This advantageously allows for the detection of an inactive capacitance element li.

[0063] The method includes a step of determining E4 the number NI of active capacitance elements li of the capacitance device 1 from the elementary distribution current Idce. In practice, the number N1 is determined from the elementary distribution current Idce and a predetermined database DB associating a number NI (N1=N-N2) of active capacitance elements li with a value of the elementary distribution current Idce. The database DB can be in the form of a curve as illustrated in [Fig. 9].

[0064] The method includes a step of determining E5 a maximum safety distribution current Idc_max_s from the number NI. In particular, the maximum safety distribution current Idc_max_s can be defined according to the following formula: 0.9*N1*S1 <Idc_max_s < N1*S1. Cela permet de garantir que chaque élément de active capacitance is not subjected to an elementary distribution current Idce that is too large.

[0065] The method includes a step of controlling the electrical generation system S by limiting the distribution current Idc to the maximum safe distribution current Idc_max_s. For example, the computer 3 can send a command to the converter C to prevent it from exceeding the maximum safe distribution current Idc_max_s, in particular by modifying the PWM control of the transistors TR. Thus, due to the limitation, certain operating points of the generation system S are no longer attainable in order to protect both the capacitor device 1 and the generation system S. Reliability and operational safety are therefore maintained despite degraded operation.

[0066] The method includes a step of emitting E7 a localized fault information DEFx of the capacitance element li associated with the current sensor 2 if the elementary distribution current Idce is zero. If it is not zero, the method includes a step of emitting E8 an absence of fault information OK in order to confirm the absence of a fault in the capacitance device 1, i.e., that all the capacitance elements li are active (N1=N).

[0067] Thanks to the control method, an S generation system can be practically tested without injecting a distribution current with a quadrature component, thus ensuring safety. If a fault is detected, the severity of the fault is advantageously measured and taken into account when operating the S generation system by prohibiting certain operating points. Safe, degraded operation is thus possible to supply the EDU electrical distribution unit. Preventive maintenance can be carried out when a fault is detected. The S generation system can therefore be used safely and its service life is extended.

Claims

Demands

1. Capacitance device (1) for an aircraft electrical generation system (S), the electrical generation system (1) comprising at least one electrical machine (M) configured to generate alternating current, at least one converter (C) for converting the alternating current from the electrical machine (M) and providing a distribution current (Idc) to a continuously powered electrical distribution unit (EDU) of an aircraft, the capacity device (1) being configured to be mounted in parallel with the converter (C) and to smooth the distribution current (Idc), the capacity device (1) comprising two terminals (B1, B2) and a plurality of capacitor elements (11) mounted in parallel, capacity device (1) characterized in that it comprises at least one current sensor (2) configured to measure an elementary distribution current (Idce) flowing through a capacitor element (11).

2. Capacitance device according to claim 1 wherein the current sensor (2) is of the Rogowski type.

3. Capacitance device according to any one of claims 1 to 2, wherein the current sensor (2) is integrated into the capacity device (1), in particular, in a resin.

4. An aircraft electrical generation system (S), the aircraft comprising at least one aircraft turbomachine (T) comprising at least one shaft (A) configured to be driven in rotation, the electrical generation system (S) comprising: • at least one electric machine (M) configured to generate alternating current by taking mechanical energy from the shaft (A), • at least one converter (C) for converting the alternating current from the electric machine (M) and supplying a distribution current (Idc) to a continuously powered electrical distribution unit (EDU) of an aircraft, • at least one capacitance device (1) according to any one of claims 1 to 3 mounted in parallel with the converter (C) for smoothing the distribution current (Vdc).

5. Aircraft comprising at least one aircraft turbomachine (T) comprising at least one shaft (A) configured to be driven in rotation, at least one electrical distribution unit (EDU) with continuous power supply and at least one electrical generation system (S) according to claim 4 to power the electrical distribution unit (EDU) by taking mechanical energy from the shaft (A).

6. Method of controlling a capacitance device (1) of an electrical generation system (S) according to claim 4, the method comprising steps of: • Supplying (E1) a test distribution current (Idc_test) to the capacitance device (1), the distribution current (Idc) being distributed in the active capacitance element(s) (I1) mounted in parallel, • Measuring (E2) an elementary distribution current (Idce) flowing in the capacitance element (I1) associated with the current sensor (2) and • Emitting (E3) a fault information (DEF) if the elementary distribution current (Idce) is greater than a determined current threshold (SI).

7. A testing method according to claim 6, wherein, the capacitance device (1) being configured to receive a maximum distribution current (Idc_max), the test distribution current (Idc_est) is defined according to the following formula: 0.9*Idc_max <Idc_test < Idc_max.

8. A control method according to any one of claims 6 to 7, wherein, the capacitance device (1) being configured to receive a maximum distribution current (Idc_max), the capacitance device (1) having a number (N) of capacitance elements (li), the determined current threshold (SI) is defined by the following formula: Sl= Idc_max / N.

9. A control method according to any one of claims 6 to 8, wherein, a current having a direct component and a quadrature component according to the Park transform, the test distribution current (Idc_test) has a quadrature component of zero value.

10. A control method according to any one of claims 6 to 9, comprising steps of: • Determining (E4) the number (NI) of active capacitance elements (li) of the capacitance device (1) from the elementary distribution current (Idce),

11. • Determine (E5) a maximum safety distribution current (Idc_max_s) from the number (NI) of active capacitance elements (li) and • Control (E6) the electrical generation system (S) by limiting the distribution current (Idc) to the maximum safety distribution current (Idc_max_s). Control method according to any one of claims 6 to 10, comprising a step of emitting (E7) a fault information (DEFx) of the capacitance element (li) associated with the current sensor (2) if the elementary distribution current (Idce) is zero.

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