ELECTRICAL CURRENT REGULATION DEVICE SUPPLIED TO A SET OF CONTACTORS

Abstract

The invention relates to a device for regulating the electric current supplied to a set of contactors, each contactor comprising a coil. The device includes means for measuring (Temp) the temperature and means for regulating (RC, R1, R2, Amp) the current delivered to the contactor coils based on the measured temperature. Figure to be published with the abbreviation: Fig. 2

Description

Title of the invention: DEVICE FOR REGULATING THE ELECTRIC CURRENT SUPPLIED TO A SET OF CONTACTORS Technical field

[0001] The present invention relates to a device for regulating the electric current supplied to a set of contactors. STATE OF PRIOR ART

[0002] Aircraft today have a large number of contactors which can be arranged in different parts of the aircraft, such as for example in the fuselage, in the nacelle of an engine or in a turbomachine.

[0003] Depending on the location of the contactor, it may be subject to large temperature variations, which is particularly the case in an aircraft.

[0004] A contactor is an electrotechnical device intended to establish or interrupt the passage of a current. A contactor is composed of a coil and two separate parts, a fixed part called the "fixed armature" and a moving part called the "moving armature". When the coil is not carrying any electric current, the fixed armature does not exert any magnetic attraction on the moving armature. The latter is kept away from the fixed armature by one or more springs, the electrical circuit is then open. When the coil is carrying sufficient current, the fixed armature attracts the moving armature which sticks to it, the circuit is now closed.

[0005] When voltage is applied to the coil of a contactor, the current is determined by the resistance value presented by the coil winding. However, the resistivity of the coil winding material varies with temperature. Thus, the current, for a given voltage, can have very different values ​​simply due to the effect of temperature.

[0006] For example, between -40°C and 150°C, the resistance presented by the winding of a coil made of a copper conductor varies from single to double. The value of the current flowing in the coil changes inversely and in the same proportion.

[0007] A current greater than necessary saturates the coil, slows down the opening of the contactor and induces a different behavior depending on the temperature. A few milliseconds of difference introduce variability to be taken into account in the validation of a system composed of a plurality of contactors. In addition, a current greater than required creates unnecessary overconsumption and Joule losses.

[0008] One solution could be to integrate into each contactor a regulation of the current delivered to the coil. This solution adds complexity to the system and risks reducing the reliability of the contactors.

[0009] It is particularly desirable to provide a solution which makes it possible to regulate the current flowing in contactor coils as a function of temperature, which does not require significant modifications to the structure of the contactors, which is simple and robust and which makes it possible to maintain a single voltage supply for controlling a plurality of contactor coils. Statement of the invention

[0010] A device is proposed for regulating the electric current supplied to a set of contactors, each contactor comprising a coil, characterized in that the device comprises:

[0011] - temperature measuring means,

[0012] - means for regulating the current delivered to the coils of the contactors from the measured temperature.

[0013] Thus, the present invention makes it possible to regulate the current flowing in contactor coils as a function of temperature without requiring significant modifications to the structure of the contactors while maintaining a single voltage supply for controlling a plurality of contactor coils.

[0014] According to a particular embodiment, the means for regulating the current delivered to the coils of the contactors based on the measured temperature vary the voltage delivered to the coils of the contactors according to a linear function.

[0015] Thus, the regulation of the current delivered to the coils of the contactors is carried out in a simple manner without adding a large number of electronic components. The linear variation of the voltage makes it possible to follow the linear variation of the resistivity of the material used for the winding of the coil.

[0016] According to a particular embodiment, the value of the delivered voltage is the same for all the coils.

[0017] Thus, the present invention makes it possible to regulate the current flowing in contactor coils as a function of temperature without requiring significant modifications to the structure of the contactors while maintaining a single voltage supply for controlling a plurality of contactor coils.

[0018] According to a particular embodiment, the value of the voltage delivered to the coils of the contactors is expressed as a function of the temperature by:

[0019] Voltage = CoeffA . Temperature + CoeffB with CoeffA = 0.08226 V / °C and CoeffB = 19.29 V.

[0020] Thus, the linear variation of the voltage makes it possible to follow the linear variation of the re- sistivity of the material used for winding the coil.

[0021] According to a particular embodiment, the value of the voltage delivered to the coils of the contactors is expressed by:

[0022] Voltage = CoeffA2 . PT100 + CoeffB2 with CoeffA2 = 0.2136 V / Ohm and CoeffB2 = -2.17 V where PT 100 is the resistance value of a PT 100 used as a temperature sensor.

[0023] Thus, the linear variation of the voltage makes it possible to follow the linear variation of the resistivity of the material used for winding the coil.

[0024] According to a particular embodiment, the temperature sensor is made of the same material used for winding the coils.

[0025] Thus, the linear variation of the voltage makes it possible to follow the linear variation of the resistivity of the material used for winding the coil.

[0026] According to a particular embodiment, the temperature sensor is arranged near the contactors.

[0027] Thus, the current regulation precisely follows the variations in the temperature of the contactors.

[0028] The invention also relates to a distribution box characterized in that it comprises a device for regulating the electric current supplied to the set of contactors and the contactors.

[0029] According to a particular embodiment, the distribution box comprises the temperature sensor.

[0030] The invention also relates to an aircraft characterized in that it comprises at least one regulation device according to the present invention. Brief description of the drawings

[0031] The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of at least one exemplary embodiment, said description being made in relation to the attached drawings, among which:

[0032] [Fig. 1] illustrates an example of a distribution box for a plurality of contactors in which the present invention is implemented;

[0033] [Fig.2] illustrates an example of implementing a regulation as a function of the temperature temperature of the voltage delivered to the plurality of contactors;

[0034] [Fig.3] illustrates an example of a table showing the variations of different pa meters depending on the temperature.

[0035] DETAILED DESCRIPTION OF EMBODIMENTS

[0036] [Fig. 1] illustrates an example of a distribution box for a plurality of contactors in which the present invention is implemented.

[0037] According to the invention, a distribution box Boi comprises a device Reg for regulating the current supplied to a plurality of contactors Contl, Cont2, Cont Nl to ContN as a function of the temperature of the distribution box Boi.

[0038] The principle of regulating the electric current delivered to the contactors Cont2 to ContN is to provide the same temperature-regulated voltage to each contactor.

[0039] The variations in the resistance presented by the coils following a known law as a function of the temperature, the value of the voltage delivered to the coils of the contactors Contl to ContN is modified so that the current flowing in the coils of the contactors is substantially constant as a function of the temperature.

[0040] The distribution box Boi comprises a controller Ctrl and a plurality of contactors Contl to ContN where N is an integer.

[0041] The Ctrl controller is for example made up of an electronic card not shown and a regulator Reg.

[0042] The controller Ctrl includes a converter (not shown) which supplies electrical energy to the coils of the contactors Contl to ContN.

[0043] For example, the distribution box Boi is supplied with electrical energy by an electrical energy supply network Res of an aircraft or by another source such as an autonomous magnet alternator. The voltage delivered by the network is for example 28 Volts DC and which can vary between 22 and 29 Volts, or even 18 and 32 V.

[0044] The converter also provides a continuous power supply Vcc to the electronic card.

[0045] [Fig.2] illustrates an example of implementing a regulation as a function of the temperature temperature of the power delivered to the plurality of contactors.

[0046] The regulator Reg is powered by a direct voltage source Vcc at least equal to 32 Volts.

[0047] The regulator Reg consists of an operational amplifier Amp, three resistors RC, RI and R2, a power stage symbolized by a transistor Tl and a diode DI.

[0048] The load BO represents the loads presented by the coils of the contactors Contl to ContN.

[0049] A first termination of the resistor RC is connected to the power supply Vcc. A second termination of the resistor RC is connected to the positive input of the operational amplifier Amp and to a first termination of a temperature sensor Temp.

[0050] The temperature sensor Temp is for example a copper resistor, or is a resistor made of the same material as the material used for winding the coils or is a PT 100 probe.

[0051] The temperature sensor Temp is for example arranged so as to provide a temperature measurement which is as close as possible to the temperature of the contactors Contl to ContN. The temperature sensor Temp is arranged in the distribution box Boi or near the Contl to ContN contactors.

[0052] The RC and Temp resistors form a divider bridge for the Vcc power supply.

[0053] A second termination of the temperature sensor Temp is connected to ground.

[0054] A first termination of the resistor RI is connected to the negative input of the operational amplifier Amp and a second termination of the resistor RI is connected to the output of the operational amplifier Amp, to the input (here the base) of the power stage T1 and to a first termination of the resistor R2.

[0055] Resistors RI and R2 define the voltage gain.

[0056] The collector of the power stage T1 is connected to the power supply Vcc and the emitter of the power stage T1 is connected to the ground and to the coils of the contactors contl to ContN.

[0057] Thus the output voltage of the regulator varies according to the temperature of the Boi case as shown in the table in [Fig.3].

[0058] [Fig.3] illustrates an example of a table showing the variations of different parameters as a function of temperature.

[0059] In the example of [Fig.3], the aircraft's electrical power supply network Res delivers a direct voltage of 28 Volts DC to 0 Volts DC.

[0060] In [Fig.3] the temperature varies from -40°C to +150°C, the variations in the resistance of the coils vary in a proportion of 1 to 1.98, the voltage delivered by the regulator Reg varies from 16 Volts at -40°C to 31.6 Volts at 150°C.

[0061] A similar table can also be obtained for other values ​​of direct voltage delivered to the contactors Contl to ContN such as for example a voltage of 100 Volts DC at 0°C.

[0062] The temperature sensor is for example a PT 100 whose value varies from 84.3 Ohms at -40°C to 157.3 Ohms at 150°C.

[0063] The coefficient to be applied to the theoretical value of the resistance of a coil at 0°C varies from 0.829 at -40°C to 1.64 at 150°C.

[0064] The output voltage value of the power stage is then expressed as a function of the temperature by:

[0065] Voltage = CoeffA . Temperature + CoeffB with CoeffA = 0.08226 V / °C and CoeffB = 19.29 V,

[0066] or depending on the measurement of a PT100 platinum probe by:

[0067] Voltage = CoeffA2 . PT100 + CoeffB2 with CoeffA2 = 0.2136 V / Ohm and CoeffB2 = -2.17 V where PT 100 is the resistance value of the PT 100.

[0068] It should be noted here that the invention has been described in the context of an implementation using analog components. The present invention can also be implemented in digital form.

[0069] The temperature sensor Temp could be a temperature measuring probe usual, for example a platinum probe.

[0070] To increase the reliability of the function, it is possible to have the same system with a double reference to ensure redundancy in the event of a measurement circuit failure.

[0071] The invention can be used in a distribution box with contactors in a highly variable environment, in particular when the distribution box is in the engine nacelle or turbomachine, in an electric hybridization system or when the distribution box is in a military aircraft hold, such as a fighter plane.

Claims

Claims

1. A device for regulating the electric current supplied to a set of contactors, each contactor comprising a coil, characterized in that the device comprises: - a temperature sensor (Temp), - means for regulating (RC, RI, R2, Amp) the current delivered to the coils of the contactors from the measured temperature.

2. The device according to claim 1, characterized in that the means for regulating the current delivered to the coils of the contactors from the measured temperature vary the voltage delivered to the coils according to a linear function.

3. The device according to claim 2, characterized in that the value of the delivered voltage is the same for all the coils.

4. The device according to claim 3, characterized in that the value of the voltage delivered to the coils is expressed as a function of the temperature by: Voltage = CoeffA. Temperature + CoeffB with CoeffA = 0.08226 V / °C and CoeffB = 19.29 V.

5. The device according to claim 3, characterized in that the temperature sensor is a PT 100 probe, the value of the voltage delivered to the coils is expressed by: Voltage = CoeffA2 . PT 100 + CoeffB2 with CoeffA2 = 0.2136 V / Ohm and CoeffB2 = -2.17 V where PT 100 is the value of the resistance of the PT 100 probe.

6. The device according to claim 1, characterized in that the temperature sensor is made of the same material used for winding the coils.

7. The device according to any one of the preceding claims, characterized in that the temperature sensor is arranged near the contactors.

8. A distribution box comprising a set of contactors characterized in that it comprises a device for regulating the electric current supplied to the set of contactors according to any one of claims 1 to 7.

9. The distribution box according to claim 8, characterized in that it comprises the temperature sensor.

10. An aircraft characterized in that it comprises at least one device for regulation according to any one of claims 1 to 7.

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