A method of contactless communication between a fixed reference frame and a rotating reference frame by encoding a power signal
The non-contact rotating electrical transformer system with encoded voltage wave trains addresses interference and maintenance issues in turbomachine power and control transmission, ensuring reliable and efficient de-icing with reduced costs and complexity.
Patent Information
- Application Number
- FR2023010873
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-10-11
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2043-10-11
AI Technical Summary
Existing methods for electrical power and control transmission between a fixed and rotating reference frame in aircraft turbomachines face challenges such as limited lifespan, high maintenance costs, interference, complexity, and unsuitability for commercial aircraft due to frequent flights, especially in contact-based and magnetic induction systems, and high costs and bulkiness in transformer-based systems.
A non-contact rotating electrical transformer system is used for power and control transmission, utilizing a voltage wave train with fixed and variable interruption times to encode switching commands, allowing simultaneous power distribution to resistors on the rotating frame, with a separate channel for both power and control signals, and dual power supply for redundancy.
This method enhances reliability, reduces maintenance, simplifies structure, lowers costs, and improves efficiency by minimizing interference and switching losses, while maintaining dynamic equilibrium and detecting faults.
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Abstract
Description
Title of the invention: Contactless communication method between a fixed reference frame and a rotating reference frame by encoding a power signal. Technical field
[0001] The present invention relates to a method of communication between a fixed reference frame and a rotating reference frame, such as the stator and rotor of a machine. More particularly, the invention relates to communication between reference frames of an aircraft turbomachine for the electrical de-icing of a propeller. Prior art
[0002] Because it is subject to variations in humidity and temperature, the aircraft is likely to become covered with frost, at least on certain parts. This is the case, for example, for a propeller of an aircraft turbomachine.
[0003] In order to prevent or reduce the formation of frost, the blades and the propeller cone are equipped with heating mats in the areas exposed to frost. The mats operate by electrothermal effect, based on a network of resistors integrated into the propeller.
[0004] There are various embodiments for the transfer of electrical power and controls between a fixed part and a rotating part, for supplying an electrothermal de-icing system of a turbomachine propeller.
[0005] Some embodiments offer transmission of electrical power and controls by contact.
[0006] For example, according to US patent 8,120,228 B2, the transmission of electrical power and commands occurs between stator brushes and rotor tracks, which carry the propeller. This design is attractive due to its simplicity, but has the disadvantage of a limited lifespan because of the friction of the brushes on the tracks. It may be acceptable on a military aircraft, for which maintenance is frequent. It is less suitable, or even completely unsuitable, on a commercial civil aircraft, especially for use with numerous daily flights. Indeed, in this case, maintenance and operating costs become excessive.
[0007] As an alternative, some designs offer contactless transmission of electrical power and controls.
[0008] For example, it is known to perform transmission by magnetic induction by superimposing a low-energy, high-frequency signal, for the control signals, onto a power signal, for the electrothermal effect. This implementation is attractive, particularly because it is compact. However, this implementation is complex to Implementation is challenging due to constraints related to managing interference between the two superimposed signals, on the one hand, and the risk of data corruption, on the other. The reliability of this implementation is not guaranteed, given the multitude of potential sources of interference: the presence of transient effects related to load switching in a rotating control unit, a large air gap, and variations in the air gap due to radial and axial displacements of the moving part relative to the fixed part.
[0009] Another example of magnetic induction transmission of power and control signals uses a second auxiliary rotating transformer dedicated to transmitting control signals. This implementation is expensive, bulky, and difficult to install on the turbomachine.
[0010] Another example of power and control transmission implements a capacitive effect. This implementation is suitable for applications where the transformer is equipped with its own bearings, therefore with a small air gap, on the order of a millimeter, and moreover controlled. Description of the invention
[0011] The invention seeks to overcome the aforementioned disadvantages and has as its general purpose the improvement of power transfer and control between a fixed reference frame and a rotating reference frame, particularly for an aircraft turbomachine.
[0012] The invention aims in particular to optimize the sequencing of power supplies for electrical resistors used in de-icing propeller blades. The invention also aims to achieve a long service life and limit maintenance interventions on the turbomachine. The invention further seeks to simplify power transfer and control transfer by reducing, or even eliminating, interference and distortions. Another objective of the invention is to simplify the structure of a turbomachine. A further objective is to limit manufacturing and operating costs. Finally, the invention aims to implement its specific features on turbomachines with a large rotating section diameter, for example, one meter or more.
[0013] In view of the foregoing, the invention relates to a data communication method for a turbomachine de-icing system comprising a fixed frame of reference and a rotating frame of reference, the system comprising a non-contact rotating electrical transformer, the primary of which is attached to the fixed frame of reference and the secondary of which is attached to the rotating frame of reference, the fixed frame of reference comprising an ice protection and control unit and a device for supplying the primary with alternating current, the protection and control unit transmitting instructions to the power supply device to adjust the level of electrical power supplied to the primary, the rotating frame of reference comprising a propeller to which are subjected to resistors, and a switch for the sequential distribution to the resistors of the electrical power transmitted to the secondary.
[0014] The protection and control unit is programmed to transmit switching commands to the switch, via the power supply and transformer, giving the power supply instructions to encode a voltage wave train applied to the primary, the switch being programmed to decode the voltage wave train recovered from the secondary.
[0015] The communication method uses the same channel dedicated to power transmission to also transmit switching commands. The same channel transmits values of different types. Therefore, the de-icing system has a simple structure, in that it is not necessary to provide a separate channel for transmitting switching commands. Among the resulting advantages are control over mass, size, and manufacturing and maintenance costs.
[0016] The voltage wave train has activation times, fixed pre-calibrated interruption times, and variable interruption times. The different durations are recognized and used by the switch to distribute electrical power to the resistors. In this way, the power supply of the fixed reference frame acts as a transmitter, and the switch of the rotating reference frame acts as a receiver. This allows for the management of two quantities: a defrost activation time and a defrost cycle time. A resulting advantage is the reliability of the transmission of switching commands and, consequently, high defrosting efficiency.
[0017] The switch performs a switching operation when the voltage wave train is interrupted. Consequently, continuity of the wave train maintains the switch in its current state. A very short interruption of the wave train is sufficient to manage the switching. Advantageously, this results in the transmission of electrical power to the resistors with the highest possible efficiency.
[0018] Switching of the switch is performed at low, or even no-load, current and voltage. This reduces stress on the switching components and improves energy efficiency by eliminating switching losses. Only conduction losses need to be considered.
[0019] The power supply device measures the primary current in order to monitor and protect the rotating frame of reference. In fact, the measurement is taken on the side of the fixed frame of reference. In this way, the power supply device is able to supervise the operation of the system on the side of the rotating frame of reference. A resulting advantage is the detection of faults such as a short circuit or an open circuit. Another advantage is ease of maintenance through the identification of faulty sectors. Furthermore, the rotating electronics are simplified.
[0020] The power supply device converts a direct current voltage into an alternating current voltage. In this case, but not limited to, the direct current voltage is high, which allows the device to receive electrical power with a low ground connection. Advantageously, this results in an aircraft equipped with the system for implementing the method being lighter.
[0021] The power supply device is duplicated. The system operates with two power supply devices to improve defrost availability.
[0022] The propeller comprises at least one pair of blades. Preferably, the two blades of a pair are diametrically opposed and heated simultaneously. Thus, the de-icing action is simultaneous on both blades. This advantageously preserves the dynamic equilibrium of the propeller, even if all pairs of blades are not at the same level of de-icing.
[0023] The invention also relates to a system implementing the data communication method for de-icing a turbomachine which includes a fixed reference frame and a rotating reference frame.
[0024] The invention also relates to an aircraft comprising the system implementing the method. Brief description of the drawings
[0025] Other objects, features and advantages of the invention will become apparent from the following description, given by way of non-limiting example, and made with reference to the accompanying drawings in which:
[0026] [Fig.1] is a descriptive diagram of an electrical power supply for a de-icing system of a turbomachine according to the proposed example of the invention,
[0027] [Fig.2] schematically represents a propeller comprising twelve blades, for the turbomachine implementing a de-icing process for the system of [Fig.1],
[0028] [Fig.3] illustrates a power-up cycle of a pair of blades of the propeller of [Fig.2],
[0029] [Fig.4] illustrates a principle of switching from one pair of blades to the next, for intermittent de-icing, for the propeller of [Fig.1] and of [Fig.2],
[0030] [Fig.5] illustrates a voltage wave train, for data communication according to the proposed example. Detailed description
[0031] Generally speaking, without this being represented, an aircraft is powered for example by at least one turbomachine comprising a propeller.
[0032] The turbomachine comprises a fixed frame of reference and a rotating frame of reference, the first being fixed to the structure of the aircraft, the second being guided by the first and carrying the propeller.
[0033] A propeller de-icing system comprises a fixed frame of reference, a rotating frame of reference, and a non-contact rotating electrical transformer (RTU) whose primary winding is attached to the fixed frame of reference and whose secondary winding is attached to the rotating frame of reference. The RTU is part of the diagram in [Fig. 1], to which reference is made.
[0034] By way of example, the rotating transformer (RTU) may include a radial air gap or an axial air gap. Regardless of its structure, the RTU ensures contactless electrical power transfer between the fixed and rotating frames of reference. Power is transferred from the primary to the secondary winding. The absence of electrical contact increases the lifespan of the RTU and contributes to improved cleanliness. Indeed, no wear dust is produced on an electrically conductive part.
[0035] The fixed reference system includes an IPC frost protection and control unit and a device for supplying the DC / AC primary with alternating current, the IPC frost protection and control unit transmitting instructions to the DC / AC power supply device to adjust a level of electrical power supplied to the primary of the RTU transformer.
[0036] By way of non-limitation, the system includes two power supply devices to increase its availability.
[0037] The turbomachine is connected to an electrical network supplying high-voltage direct current (HVDC), allowing it to be powered by a low-mass electrical chain. Values of 450V or 800V for the direct current are very suitable. In fact, the primary winding supply converts direct current into alternating current. Thus, the voltage available to supply the primary winding of the RTU transformer is alternating, which allows power to be transferred to the secondary winding by the action of an alternating magnetic field.
[0038] The IPC protection and control unit transmits instructions to the DC / AC power supply device to adjust a level of electrical power supplied to the primary.
[0039] The rotating frame of reference, for its part, comprises the propeller to which resistances are attached. These are, for example, in the form of heating mats operating by electrothermal effect, mats integrated into the blades in areas exposed to frost.
[0040] The rotating reference frame also includes a switch for the sequential distribution to the resistors of the electrical power transmitted to the secondary.
[0041] The IPC protection and control unit is programmed to transmit switching commands to the switch via the DC / AC power supply and the RTU transformer. The IPC instructs the DC / AC power supply to encode a voltage wave train applied to the primary winding. The switch is programmed to decode the voltage wave train transmitted to the secondary winding by the primary winding. This encoding creates on-times and off-times within the voltage wave train. Consequently, the wave train carries electrical power on the one hand, and codes used for the operation of the switch on the other.
[0042] In the example described, as shown in [Fig. 2] without limitation, a propeller 1 comprises six pairs of blades PI, P2, P3, P4, P5, P6, each pair being called a segment. The two blades of a segment are diametrically opposed. The blades are evenly distributed around the periphery of the propeller, with two sets of blades PI to P6. The angular separation between two successive blades is 30°, and the angular separation between two blades of a segment is 180°.
[0043] Without limitation, the blades PI to P6 all have the same structure. They all have the same length.
[0044] The sequential distribution of electrical power to the resistors is done segment by segment. The two blades of the same segment are powered simultaneously. Segments P1 to P6 are powered in turn, according to cycles, for example successively.
[0045] Figure 3 shows the power supply to the first PI segment, with a defrost activation time DI along the x-axis (Ox), a cycle time D along the x-axis (Ox), and the electrical power intensity along the y-axis (Oy). The DI duration is variable and depends on the icing conditions. The switch intrinsically receives information on the icing conditions by adjusting the DI duration.
[0046] Figure 4 shows the successive activation of the six pairs of blades or segments P1, P2, P3, P4, P5, and P6. Without limitation, the respective de-icing activation times D1, D2, D3, D4, D5, and D6, along the x-coordinate Ox, are equal. These times are variable, depend on the icing conditions, and are calculated by the system supervisor. The switch receives information on the icing conditions intrinsically by adjusting the times D1 to D6. The cycle time D is also referenced in Figure 4. An activation interruption I separates two successive activation sequences of segments P1 to P6.
[0047] The sequential power distribution is carried out by the switch, on instructions from the IPC frost protection and control unit, as shown in [Fig. 5]. The wave train supplied to the switch, referenced To, occurs over time along the x-axis Ox, with intensity along the y-axis Oy. The IPC protection and control unit interrupts the wave train To with varying durations.
[0048] First, fixed-duration interrupts Ic2, Ic3, Ic4, and Ic5 are provided. These are interpreted by the switch as segment change commands, to move from segment n to segment n+1. Second, variable-duration Intl interrupts are provided, depending on the icing conditions. Each of these is interpreted by the switch as the end of a power supply sequence for all segments P1 to P6. The duration of this Intl interrupt is adjusted to account for the duration D of a defrost cycle. A variable Intl interrupt duration can occur at any time.
[0049] The switch is programmed to restart a new defrosting sequence from the first PI segment when power is restored.
[0050] Each switching operation performed by the switch, both opening and closing, is carried out at low, or even negligible, current and voltage. This reduces stress on the components and improves efficiency by eliminating switching losses.
[0051] By controlling the applied cycles, the power supply device is aware at all times of the reference of the powered segment. Thus, by measuring the current taken at the primary of the transformer, on the stationary side, the power supply device is able to monitor the rotating reference frame; it can detect faults such as a short circuit or an open circuit for each of the segments P1 to P6.
[0052] A variant of the described example involves introducing additional encoding of the interrupt duration to transmit the segment reference P1, P2, P3, P4, P5, P6 to the switch. The fixed interrupt duration Ic2, Ic3, Ic4, Ic5 is replaced by a set of duration ranges, according to the following values.
[0053] PI segment: upon power-up,
[0054] Segment P2: interruption duration, for example from 10 to 15ms,
[0055] Segment P3: interruption duration, for example from 20 to 25ms,
[0056] Segment P4: interruption duration, for example from 30 to 35ms,
[0057] Segment P5: interruption duration, for example 35 to 40ms,
[0058] Segment P6: interruption duration for example of 45 to 50ms.
[0059] Pause between two cycles with a duration that varies depending on the cycles.
[0060] In general, the invention has the advantage of simplicity, its implementation being carried out by specific programming at the level of the protection and control unit, as well as at the level of the switch.
[0061] Obviously, the invention is not limited to the example of embodiment and implementation described above, and includes all equivalents which fall within the scope of the claims that will follow.
[0062] In particular, it is possible to provide for a different number of blades. Furthermore, a power supply device can use an alternating voltage available on the aircraft.
Claims
Demands
1. A data communication method for a turbomachine de-icing system comprising a fixed reference frame and a rotating reference frame, the system comprising a non-contact rotating electrical transformer (RTU) having a primary connected to the fixed reference frame and a secondary connected to the rotating reference frame, the fixed reference frame comprising an ice protection and control unit (IPC) and a device for supplying (DC / AC) power to the primary with alternating current, the protection and control unit (IPC) transmitting instructions to the power supply device (DC / AC) to adjust the level of electrical power supplied to the primary, the rotating reference frame comprising a propeller (1) to which resistors are connected, and a switch for the sequential distribution to the resistors of the electrical power transmitted to the secondary,characterized by the fact that the protection and control unit (IPC) is programmed to transmit switching commands to the switch, via the power supply device (DC / AC) and the transformer (RTU), giving the power supply device (DC / AC) instructions (Ici, Ic2, Ic3, Ic4, Ic5, Intl) to encode a voltage wave train (To) applied to the primary, the switch being programmed to decode the voltage wave train (To) recovered from the secondary.
2. A method according to claim 1, wherein the voltage wave train (To) has activation times (D1, D2, D3, D4, D5, D6), pre-calibrated fixed interruption times (Ici, Ic2, Ic3, Ic4, Ic5), and variable interruption times (Intl).
3. Method according to claim 1 or 2, wherein a switching is performed by the switch during an interruption of the voltage wave train.
4. A method according to any one of claims 1 to 3, wherein switching of the switch is carried out at low current and voltage, or even nuisance.
5. A method according to any one of claims 1 to 4, wherein the (DC / AC) power supply device measures the primary current, in order to monitor and protect the rotating reference frame.
6. A method according to any one of claims 1 to 5, wherein the (DC / AC) power supply device converts a direct current voltage into an alternating current voltage.
7. A method according to any one of claims 1 to 6, wherein the (DC / AC) power supply device is doubled.
8. A method according to any one of claims 1 to 7, wherein the propeller (1) comprises at least one pair of blades (PI, P2, P3, P4, P5, P6).
9. A turbomachine de-icing system comprising a fixed reference frame and a rotating reference frame, the system comprising a non-contact rotating electrical transformer (RTU) having a primary connected to the fixed reference frame and a secondary connected to the rotating reference frame, the fixed reference frame comprising an ice protection and control unit (IPC) and a device for supplying (DC / AC) power to the primary with alternating current, the protection and control unit (IPC) transmitting instructions to the power supply device (DC / AC) to adjust the level of electrical power supplied to the primary, the rotating reference frame comprising a propeller (1) to which resistors are connected, and a switch for the sequential distribution to the resistors of the electrical power transmitted to the secondary,characterized by the fact that the protection and control unit (IPC) is programmed to transmit switching commands to the switch, via the power supply device (DC / AC) and the transformer (RTU), giving the power supply device (DC / AC) instructions (Ici, Ic2, Ic3, Ic4, Ic5, Intl) to encode a voltage wave train (To) applied to the primary, the switch being programmed to decode the voltage wave train (To) recovered from the secondary.
10. Aircraft comprising the system according to claim 9.