阅读说明：本技术 用于具有涡轮喷气发动机的飞行器的内部混合的转换和输送电能的系统 (System for internally mixed conversion and transmission of electrical energy for aircraft with turbojet engine ) 是由 J-P·H·萨兰纳 S·佩蒂邦 F·罗吉尔 R·默尼耶 M·阿伯德拉蒂夫 于 2019-10-22 设计创作，主要内容包括：在由至少一个涡轮喷气发动机推动的飞行器中,可以经由高压(100、120)和/或低压(102、122)涡轮轴从中提取动力或向其中注入动力,并且包括至少一个用于确保功率瞬变的燃气轮机,提供了一种用于转换和输送电能的系统,其中,每个高压和/或低压涡轮轴都连接到第一双馈送异步电机(48、50、52、54),将第一三相AC电压递送到AC分配网(46),并且将用于第一双向AC/DC转换器(56、58、60、62)的第二多相AC电压将DC电压提供到DC分配网(64),连接到DC分配网的至少一个第二双向DC/AC转换器(66、68)将该DC电压转换为第三多相AC电压,第三多相AC电压供应与燃气轮机的旋转轴(140、160)接合的至少一个第二双馈送电异步电机(70、72),第二双馈送异步电机还向AC分配网递送第四多相交流电压。(In an aircraft propelled by at least one turbojet engine, from which or into which power can be extracted via high-pressure (100, 120) and/or low-pressure (102, 122) turbine shafts and comprising at least one gas turbine for ensuring power transients, a system for converting and transporting electrical energy is provided, in which each high-pressure and/or low-pressure turbine shaft is connected to a first dual-fed asynchronous machine (48, 50, 52, 54), delivers a first three-phase AC voltage to an AC distribution network (46), and supplies a second multi-phase AC voltage for a first bi-directional AC/DC converter (56, 58, 60, 62) to a DC distribution network (64), at least one second bi-directional DC/AC converter (66, 68) connected to the DC distribution network converts this DC voltage into a third multi-phase AC voltage, which is supplied to a rotating shaft (140, 122, 140, b) of the gas turbine, 160) At least one second double-fed electric asynchronous machine (70, 72) engaged, the second double-fed asynchronous machine also delivering a fourth multi-phase alternating current voltage to the AC distribution network.)

1. System for converting and transporting electric energy on board an aircraft propelled by at least one turbojet engine (10, 12), on which system power is extracted or injected via high-voltage (100, 120) and/or low-voltage (102, 122) turbine shafts, and comprising at least one gas turbine (14, 16) providing power transients, characterized in that each of said high-voltage and/or low-voltage turbine shafts is connected to a first double-fed asynchronous machine (48, 50, 52, 54) which delivers, on the one hand, a first three-phase AC voltage on an AC distribution network (46) and, on the other hand, a second multiphase AC voltage for a first AC/DC bidirectional converter (56, 58, 60, 62) which supplies a DC voltage on a DC distribution network (64), at least one second DC/AC bidirectional converter (66, a, 68) Converting the DC voltage into a third multi-phase AC voltage that supplies at least one second double-fed electric asynchronous machine (70, 72) that is engaged with a rotating shaft (140, 160) of the at least one gas turbine (14, 16), the second double-fed asynchronous machine also delivering a fourth multi-phase AC voltage over the AC distribution grid.

2. System for converting and transporting electric energy according to claim 1, characterized in that it further comprises a storage unit (44) installed directly in parallel on said DC distribution network.

3. System for converting and transporting electric energy according to claim 1 or 2, characterized in that all high power electrical protectors (contactors and/or circuit breakers) are arranged on the AC distribution grid.

4. A system for converting and transporting electrical energy as claimed in any one of claims 1 to 3 wherein the double-fed asynchronous machine is a wound rotor induction generator, the stator windings of which are directly connected to the AC distribution grid and the rotor windings of which are connected to the AC/DC bi-directional converter.

5. An aircraft comprising a system for converting and transporting electrical energy according to any one of claims 1 to 4.

6. The aircraft according to claim 5, characterized in that it is of the SMR type, comprising two turbojet engines (10, 12) and two gas turbines (14, 16).

7. Method for managing faults in a system for converting and transporting electric energy according to any one of claims 1 to 4, comprising the steps of:

performing a troubleshooting test (E102);

when a fault is detected, looking up the nature of the fault (E104, E106, E108);

deactivating the MADA controller (E110, E116) when the fault involves the MADA or the MADA controller.

Technical Field

The present invention relates to the general field of "more electric" propulsion architectures, and more specifically to internal mixing of aircraft propellers.

Background

Most high power propulsion solutions have one or more gas turbines as their supply that provide mechanical power to a rotating shaft. In particular, beyond a certain flight time or a certain propulsion power, the electric storage unit (for example a battery, a fuel cell or an ultracapacitor) is not sufficiently capable of being used alone, and it is therefore necessary to transmit mechanical power from one shaft to one or more other shafts in order to obtain a better operating point by sizing the propellers or by providing propulsion assistance based on auxiliary sources.

Systems for converting and delivering electrical energy in aircraft typically exhibit one of two types of architectures:

the most common DC architecture, which consists of a generator (power supply) equipped with rectifiers that convert all the AC power to DC, then distribute it, then convert it back to AC power through an inverter, in order to power the electric motor and the different electrical loads. This architecture allows the operating points of the load and the supply to be completely decoupled and allows the shaft rotation speed to be variable from- Ω max to + Qmax.

AC architectures, less common, except for power greater than MW, consist of a generator directly coupled to an electric motor or electrical load. This architecture allows a fixed coupling between the speed of the engine shaft and the speed of the shaft of different loads and, thanks to the elimination of the power converter, high efficiency and better reliability.

For internal mixing of turbojet engines, there are only solutions of DC architecture, since the rotation speed is variable and therefore AC architecture cannot be envisaged.

Fig. 3 shows such a known architecture in the context of an SMR (short-medium range) type aircraft propelled by two turbojet engines 10, 12, each under each wing, on which power can be taken or injected via its high-pressure HP and/or low-pressure LP turbine shafts. Two gas turbines 14, 16, typically located at the end of the fuselage of an aircraft, may also be used to provide power transients. In this DC architecture, each of the HP 100, 120 and BP 102, 122 shafts of the two turbojet engines is typically linked to the synchronous machines 18, 20, 22, 24 by a permanent Magnet (MSAP) so as to deliver a three-phase alternating voltage to the AC/DC static converters 26, 28, 30, 32, providing a DC voltage (typically ± 270V DC) on the DC distribution network 34. Two inverters 36, 38 connected to the network convert the DC voltage to a three-phase AC voltage, supplying two synchronous machines 40, 42, each engaged with a rotating shaft 140, 160 of the gas turbines 14, 16 with electrical power. All high-power electrical protectors (contact switches and other circuit breakers not shown) are arranged on the DC distribution network. The storage units 44 may also be mounted directly in parallel on the DC distribution network.

However, such architectures do have a number of drawbacks: short circuit faults inside permanent magnet machines must be addressed because it is considered critical and necessarily involve redundancy (thus increasing weight), the loss of the static converter causes the loss of the associated generator, which makes any reconfiguration difficult, or here also involves adding redundancy (thus still increasing weight) for each type of converter, the mass of the protector increases because the architecture is a DC voltage and, due to the multiple conversions made along the line, the overall efficiency of the line is reduced (efficiency of about 80%).

Disclosure of Invention

The main object of the present invention is therefore to alleviate these drawbacks by proposing a new architecture particularly suitable for aircraft interior mixing.

These objects are achieved by a system for converting and transporting electric energy in an aircraft propelled by at least one turbojet engine, from which power can be taken or injected via high-pressure and/or low-pressure turbine shafts, and comprising at least one gas turbine to provide power transients, characterized in that each of said high-pressure and/or low-pressure turbine shafts is connected to a first double-fed asynchronous machine delivering, on the one hand, a first three-phase AC voltage on an AC distribution network and, on the other hand, a second multiphase AC voltage for a first AC/DC bidirectional converter supplying a DC voltage on the DC distribution network, at least one second DC/AC bidirectional converter being connected to said DC distribution network, converting this DC voltage into a third multiphase AC voltage supplying at least one second double-fed asynchronous machine engaged with the rotating shaft of the at least one gas turbine, the second double-fed asynchronous motor also delivers a fourth multi-phase AC voltage on the AC distribution grid.

By using a double-fed asynchronous machine which allows the main power to be delivered AC and controlled DC, i.e. a machine comprising two galvanically isolated supply channels, the advantages of the AC and DC architectures are combined. In addition, by using a bidirectional converter supplying part of a double-fed asynchronous motor, it is possible to have an operation mode of a weakly variable speed.

Preferably, the system further comprises a storage unit mounted directly in parallel on said DC distribution network.

Advantageously, all high power electrical protectors (contact switches and/or circuit breakers) are provided on the AC distribution network.

Preferably, said double-fed asynchronous machine is a wound rotor induction generator, the stator windings of which are directly connected to said AC distribution network and the rotor windings of which are connected to said AC/DC bi-directional converter.

Drawings

Further features and advantages of the invention will become apparent from the description given hereinafter with reference to the accompanying drawings, which illustrate exemplary embodiments of the invention without any limitation. In the drawings:

figure 1 shows an operational diagram of an architecture providing internal mixing of an aircraft according to the invention,

FIG. 2 is a flow chart showing fault management in the architecture of FIG. 1, an

Figure 3 shows an operational diagram of an architecture providing internal mixing of an aircraft of the prior art.

Detailed Description

Fig. 1 shows a system for converting and transporting electrical energy in an aircraft according to the invention, wherein the transport of main power is provided by an AC distribution network 46, like an AC architecture.

The description below refers to an SMR type aircraft similar to that shown in fig. 3, i.e. propelled by two turbojet engines, on which power can be extracted or injected via the high-pressure 100, 120 and/or low-pressure 102, 122 shafts, depending on the mode of operation implemented, the aircraft also comprising two gas turbines to provide power transients. Of course, this aircraft configuration is in no way limiting and may also be applied, for example, to an aircraft having a single turbojet comprising only a single gas turbine or to an aircraft having n turbojet engines (n > 2). Also, if the AC voltages are three-phase in the following description, they may of course also be multi-phase (number of phases > 3).

According to the invention, each of the high-and/or low-pressure shafts of the two turbojet engines is connected to a first double-fed asynchronous machine 48, 50, 52, 54 which, on the one hand, delivers a first three-phase AC voltage on the AC distribution network 46 and, on the other hand, delivers a second three-phase AC voltage for a first AC/DC bidirectional converter 56, 58, 60, 62 which provides a DC voltage on a DC distribution network 64, the second DC/AC bidirectional converter 66, 68 being connected to the DC distribution network which converts this DC voltage into a third three-phase AC voltage which supplies a second double-fed asynchronous machine 70, 72, which is connected to a power supply which is coupled to the rotating shafts 140, 160 of the two gas turbines, these second double-fed asynchronous machines also delivering a fourth three-phase AC voltage on the AC distribution network 46. The storage units 44 are mounted directly in parallel on the DC distribution network 64.

Compared with conventional asynchronous machines, doubly-fed machines have the particularity of having two electrically isolated supply channels. The isolation of the two MADA supplies allows for no fault propagation between the two channels and operation in degraded mode. Specifically, if a MADA's rotor channels are lost, the machine can continue to operate in the degraded mode by shorting the rotor channels.

Another advantage provided by the electrical isolation is the possibility of having two different voltage levels. For example, the main channel of the MADA, which sees most of the power passing, may be at a high voltage, while the rotor path, which sees least of the power passing, may be at a lower voltage. These voltages can be adapted as required, so that it is possible to optimize the dimensions (in particular in terms of quality) of the system.

A double-fed asynchronous Machine (MADA) is a wound rotor induction generator, the stator windings of which are directly connected to the AC distribution grid and the rotor windings of which are connected to an AC/DC bidirectional converter. The converter is reversible in that in super-synchronous operation the rotor power travels in one direction, while in sub-synchronous operation the rotor power travels in the opposite direction. It should be noted that such an asynchronous machine has the advantage of enabling a mechanical torque to be generated on the output shaft even if the rotational speed of the magnetic field differs from the rotational speed of the rotor. Unlike conventional synchronous machines, in which the rotational speed of the rotor is proportional to the electrical frequency at the level of the stator, this also allows the rotor rotational speed to be adjusted according to the electrical frequency at the level of the stator and rotor.

More specifically, in super-synchronous operation, the generator rotates at a rotational speed higher than the synchronous speed, and then the converter operates as a rectifier, delivering a DC voltage to the DC distribution network. Similarly, in subsynchronous operation, the generator rotates at a rotational speed that is lower than the synchronous speed, and then the converter operates as an inverter, delivering AC voltage from the DC distribution grid to the MADA. The inverter adjusts the amplitude and frequency of the signal to be sent to the rotor, causing the speed to change, thereby changing the power extracted from the MADA.

By the construction of the conversion system according to the invention, there are the same number of converters as in the DC architectures of the prior art, but these converters handle only a fraction (about 25% to 30%) of the nominal power delivered, which makes it possible to choose a lighter, less bulky and cheaper converter, whereas in the DC architecture the electrical converters are dimensioned so that the nominal power passes through. Even though the MADA is heavier than the MSAP of the prior art DC architecture, the components are lighter (about 5% to 10%) because the converter is much less powerful. Also, all high power electrical protectors (contactors and/or circuit breakers) are placed on the AC distribution network, rather than on the DC distribution network, which in turn reduces volume and cost.

Furthermore, in the case of internal mixing, it is possible to separate the DC distribution network, which acts to vary the mechanical shaft speed, from the AC distribution network on which the main power travels, which makes it possible to obtain better efficiencies (approximately 2% to 5% higher) and simplifies the isolation problem by ensuring galvanic isolation between the main power providing propulsion and its control.

Finally, by the present invention, a failure of one of the converters reduces line operation between the supply and the load, but does not stop it, as shown in the flow chart in fig. 2, which depicts fault management in a system for converting and delivering electrical energy for use in the present invention. The first step E100 corresponds to the normal operation of the system of the invention, detecting a fault in the subsequent test step E102. In the case of no fault, the process returns to step E100, but if a fault is detected (response to test of step E102 is yes), three tests are performed in steps E104, E106 and E108 to find the nature of the fault, response to the first test step E104 is yes, indicating that a fault is detected on the MADA, response to the second test step E106 is yes, indicating that a fault is detected on the converter controlling the MADA, response to the third test step E108 is yes, indicating that a fault is of another nature (e.g. phase loss or poor grid quality). If a fault is detected on the MADA, the converter controlling the MADA is deactivated in step E110 (which is sufficient to ensure that the fault does not propagate), thereby putting the system into a degraded mode of operation (step E112) as long as the fault remains unresolved or corrective maintenance is performed (step E114). If a fault is detected on the converter controlling the MADA, in a subsequent step E116 the relevant converter will be deactivated and the MADA reduced to asynchronous operation by short-circuiting the rotor of the MADA (step E118), thereby bringing the system again to the degraded mode of operation of step E112, which will persist as long as the fault has not yet been removed or corrective maintenance performed (step E114). If the fault is of another kind, then as long as the fault is not resolved or corrective maintenance is performed (step E114), the fault causing the system to enter a degraded mode of operation is processed (step E112) in step E120. Regardless of the nature of the detected fault, once the fault is resolved or appropriate corrective maintenance is performed (step E114), it is then possible to return to the normal operating mode of step E100.

Thus, by means of the present invention, an optimized architecture for internal mixing is proposed, which enables the transmission of power between the shafts of the turbojet (propeller) and provides propulsion assistance from the gas turbine (auxiliary source). Propellants are the primary power source for an aircraft and therefore must provide the energy required by the non-propulsion systems of the aircraft. However, depending on the transients considered (the operating point transients of the propellers determine the size of the turbojet), power is transmitted from the LP shaft to the HP shaft or vice versa. Thus, the LP shaft of the propeller is able to perform extraction and provide propulsion assistance, and a gas turbine optimized for low power enables additional power during certain phases of flight while providing better energy density than a battery.