Ac power generation comprising a non-inductive overvoltage protection device

Abstract

The invention relates to a fast overvoltage and slow overvoltage protection device (1) arranged in parallel with an alternating current generation channel (L1-L2), the protection device (1) comprising: - a first current source (S1) comprising an input (S11) and an output (S12), the input (S11) of the first current source (S1) being connected to a first terminal (L1) of the generation channel; - a second current source (S2) comprising an input (S21) and an output (S22), the input (S21) of the second current source (S2) being connected to a second terminal (L2) of the generation channel, the output (S22) of the second current source (S2) being connected to the output (S12) of the first current source (S1).

Description

DESCRIPTION AC ELECTRICAL GENERATION INCLUDING A NON-INDUCTIVE OVERVOLTAGE PROTECTION DEVICE

[0001] The invention relates to the protection of loads connected to an alternating current electrical generation channel. More specifically, the invention concerns protection against overvoltages in an alternating current electrical network. The invention is of particular interest in the field of aeronautics in which the safety of alternating current electrical circuits and networks is essential, but is also of interest in the field of electricity generation in a network requiring, for example, the use of an inductive machine.

[0002] In an AC power grid, different types of surges can be detected, either fleeting or more lasting. And, these surges can damage electrical or electronic equipment and lead to catastrophic events, particularly for systems associated with high availability and a low failure rate.

[0003] Currently, two types of overvoltage can be identified: - “Fast” surges for which the reaction time to compensate for the surge must be short otherwise it will have a major impact on the electrical network, - “Slow” surges inducing greater energy generation but not requiring a low reaction time for surge management in the network.

[0004] Usually, protection against fast overvoltages and slow overvoltages is achieved by different protection systems.

[0005] Thus, in order to protect the AC power grid against a rapid surge, a user may decide to incorporate into the circuit: - A Zener Transil diode or an active clipper which has a very low reaction time, i.e. less than a nanosecond, but only allows a small amount of energy to be absorbed. In addition, this type of component has an overvoltage tolerance of less than 5%, i.e. the overvoltage must not be very high compared to the voltage usually measurable in the network and generates high frequency disturbances when used, - A zinc oxide varistor which has a low reaction time, between ten nanoseconds and a hundred nanoseconds but can also only absorb a small amount of energy. In addition, this type of component has a tolerance to overvoltage that is relatively higher compared to the zener diode but still low. However, unlike the zener diode, the ZNO varistor has the advantage of not generating any disturbance in the network, - A gas discharger which has a relatively longer reaction time compared to the components mentioned above, namely from a few microseconds to milliseconds, but which has the advantage of absorbing a large amount of energy during the overvoltage. In addition, its tolerance to the overvoltage is then also significant compared to the components mentioned above. However, this component has the disadvantage of making the network unavailable, - Finally, a crowbar resistor can also be considered. This component has a reaction time and energy absorption capacity equivalent to the characteristics of the gas discharger. However, this component has an overvoltage tolerance equivalent to the ZNO varistor and induces unavailability of the electrical network during its use.

[0006] However, none of these components can protect the network when a slow surge occurs, generating significant energy in the network.

[0007] Therefore, in order to protect the circuit during a slow overvoltage, the skilled person may decide to add a switched resistor to the circuit to absorb the energy generated. However, this component also generates an overvoltage when opened.

[0008] Thus, there is currently no component that can accommodate a fast surge and a slow surge, and the person skilled in the art is forced to add several components to their network, which is sometimes not feasible when the available space is limited.

[0009] The invention aims to overcome all or part of the problems mentioned above by proposing a protection device against rapid overvoltages and slow overvoltages which does not generate distortion and does not reduce the available power of the electrical network.

[0010] In addition, this protection device is advantageously characterized by a low reaction time, namely less than a microsecond, and its ability to clip positive and negative overvoltages independently.

[0011] To this end, the subject of the invention is an electrical energy generator configured to generate electrical energy to a load via an alternating current generation channel, the electrical energy generator comprising a fast overvoltage and slow overvoltage protection device arranged in parallel with the alternating current generation channel, the protection device comprising: - A first current source comprising an input and an output, the input of the first current source being connected to a first terminal of the generation channel, - A second current source comprising an input and an output, the input of the second current source being connected to a second terminal of the generation channel, the output of the second current source being connected to the output of the first current source.

[0012] According to one aspect of the invention, the first current source and / or the second current source are configured to generate a current proportional to a voltage measurable at the first current source or the second current source.

[0013] According to one aspect of the invention, the overvoltage protection device comprises an overvoltage detector configured to detect an overvoltage level between the first terminal and the second terminal of the generation channel, the overvoltage level being a voltage value between the first terminal and the second terminal of the generation channel greater than a first predefined threshold voltage value.

[0014] According to one aspect of the invention, the first current source comprises: a first transistor, the first transistor comprising: o a first terminal connected to the first terminal of the generation channel, o a second terminal connected to the first terminal of the generation channel, o a third terminal connected to the second current source, - a first diode comprising a cathode connected to the first terminal of the first transistor and an anode connected to the third terminal of the first transistor, - a first resistor arranged between the first terminal of the generation channel and the second terminal of the first transistor and connected to the overvoltage detector, - a first current regulating device connected to the overvoltage detector, arranged between the first resistor and the second terminal of the first transistor and configured to limit the current flowing through the first transistor to a predefined current value.

[0015] According to one aspect of the invention, the first current source comprises a first activation device of the first regulation device connected to the overvoltage detector configured to switch from a deactivated state, in which the first regulation device is inactive, to an activated state, in which the first regulation device is active, when the overvoltage detector detects the overvoltage level, the first activation device comprising: - A first auxiliary voltage detector configured to determine a voltage value between the first terminal and the second terminal of the generation channel, - A first current detector disposed between the third terminal of the first transistor and the second current source configured to determine a current value at the third terminal of the first transistor, the first activation device being configured to switch from the activated state to the deactivated state when the voltage value determined by the first auxiliary voltage detector is less than a second predefined voltage value and when the current value determined by the first current detector is zero.

[0016] According to one aspect of the invention, the second current source comprises: - a second transistor, the second transistor comprising: o a first terminal connected to the second terminal of the generation channel, o a second terminal connected to the second terminal of the generation channel, o a third terminal connected to the first current source, - a second diode comprising a cathode connected to the first terminal of the second transistor and an anode connected to the third terminal of the second transistor, - a second resistor arranged between the second terminal of the generation channel and the second terminal of the second transistor and connected to the overvoltage detector, - a second current regulating device connected to the overvoltage detector, arranged between the second resistor and the second terminal of the second transistor and configured to limit the current flowing through the second transistor to a predefined current value.

[0017] According to one aspect of the invention, the second current source comprises a second activation device of the second regulation device connected to the overvoltage detector configured to switch from a deactivated state, in which the second regulation device is inactive, to an activated state, in which the second regulation device is active, when the overvoltage detector detects the overvoltage level, the second activation device comprising: - A second auxiliary voltage detector configured to determine a voltage value between the first terminal and the second terminal of the generation channel, - A second current detector disposed between the third terminal of the second transistor and the first current source configured to determine a current value at the third terminal of the second transistor, the second activation device being configured to switch from the activated state to the deactivated state when the voltage value determined by the second auxiliary voltage detector is less than a third predefined voltage value and when the current value determined by the second current detector is zero.

[0018] According to one aspect of the invention, the first transistor is a bipolar transistor.

[0019] According to one aspect of the invention, the second transistor is a bipolar transistor.

[0020] According to one aspect of the invention, the protection device comprises a device for opening the protection device.

[0021] According to one aspect of the invention, the protection device comprises a first protection unit, the first protection unit comprising the first current source and the second current source, the protection device comprising at least one additional protection unit comprising a first additional current source identical to the first current source and a second additional current source identical to the second current source, the at least one additional protection unit being arranged in bypass of the first protection unit.

[0022] The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

[0023] [Fig.1] Figure 1 represents a schematic view of a fast overvoltage and slow overvoltage protection device according to the invention;

[0024] [Fig.2] Figure 2 represents an enlarged view of the protection device of Figure 1;

[0025] [Fig.3] Figure 3 represents a structural view of the protection device of Figure 1;

[0026] [Fig.4] Figure 4 represents the protection device according to a first variant;

[0027] [Fig.5] Figure 5 represents the protection device according to a second variant;

[0028] [Fig.6] Figure 6 represents a timing diagram of the impact of the protection device on the electrical machine according to the invention;

[0029] [Fig.7A] Figure 7A represents a timing diagram of the wave behavior in an electrical generation channel in the absence of the protection device according to the invention;

[0030] [Fig.7B] Figure 7B represents a timing diagram of the wave behavior in an electrical generation channel in the presence of the protection device according to the invention.

[0031] For the sake of clarity, the same elements will have the same references in the different figures.

[0032] Figure 1 thus represents a schematic view of an electrical energy generator 100 configured to generate electrical energy to a load CH by means of a channel for generating an electric current L1-L2. The load CH is thus connected in parallel with the channel for generating the electric current L1-L2. The energy generator comprises a fast overvoltage and slow overvoltage protection device 1 arranged in parallel with a channel for generating an alternating current L1-L2 between a first terminal L1 and a second terminal L2. The protection device is arranged in parallel with the load CH. As stated previously, the current between the first terminal L1 and the second terminal L2 at the generation channel L1-L2 is an alternating current, which means that the direction of the electric current can be from the first terminal L1 towards the second terminal L2 or from the second terminal L2 towards the first terminal L1.The protection device 1 is therefore arranged according to its own channel 10 parallel to the generation channel L1 -L2.

[0033] The protection device 1 comprises a first current source S1 comprising an input S11 and an output S12. And, the input S11 of the first current source S1 is connected to the first terminal L1 of the generation channel L1-L2.

[0034] The protection device 1 also comprises a second current source S2 which also comprises an input S21 and an output S22. And, the input S21 of the second current source S2 is connected to the second terminal L2 of the generation channel L1 -L2 while the output S22 of the second current source S2 is connected to the output S12 of the first current source S1.

[0035] The first current source S1 is thus directly connected to the second current source S2 via the connection between the output S12 of the first current source S1 and the output S22 of the second current source S2.

[0036] This arrangement thus has the advantage of being able to regulate any positive or negative overvoltage depending on the direction of the current.

[0037] In other words, the first current source S1 and the second current source S2 are positioned in series on the channel 10. And, the second current source S2 is positioned so as to be opposite the first current source S1. The second current source S2 is thus positioned "head to tail" with respect to the first current source S1.

[0038] Thus, when the direction of the current is from the first terminal L1 towards the second terminal L2, then the first current source S1 is active because it is in the direction of the current while the second current source S2 is, for its part, opposite to the direction of the current and therefore inactive. Conversely, when the direction of the current is from the second terminal L2 towards the first terminal L1, then the second current source S2 is active because it is in the direction of the current while the first current source S1 is, for its part, opposite to the direction of the current and therefore inactive.

[0039] Alternatively, the first current source S1 and / or the second current source S2 may be an active controlled current generation means.

[0040] By first current source S1 and second current source S2, it is understood that the first current source S1 and the second current source S2 are devices capable of producing an electric current operating over a voltage range.

[0041] More precisely, the measurable voltage at the generation channel L1 - L2 being identical to the measurable voltage at the channel 10. If an overvoltage is detected between the first terminal L1 and the second terminal L2, this overvoltage is also detected at the protection device 1. Now, the current being proportional to the voltage at the terminals of the generation channel L1 - L2 and in the channel 10, the protection device 1 makes it possible, by adapting the current, to regulate the voltage in the protection device 1 and in the generation channel L1 - L2.

[0042] In other words, when the direction of the electric current is from the first terminal L1 to the second terminal L2 and an overvoltage is detected at the generation channel L1-L2, then the first current source S1 makes it possible to generate an electric current in the channel 10 so as to regulate the voltage on this same channel 10 and therefore also in the generation channel L1-L2 so as to limit the overvoltage. And, when the direction of the electric current is from the second terminal L2 to the first terminal L1 and an overvoltage is detected at the generation channel L1-L2, then the second current source S2 makes it possible to generate an electric current in the channel 10 so as to regulate the voltage on this same channel 10 and therefore also in the generation channel L1-L2 so as to limit the overvoltage.The protection device 1 therefore makes it possible to limit the voltage in the circuit, namely the generation channel L1 -L2 and the channel 10, by regulating the current passing through the protection device 1 in a very short time, less than a nanosecond.

[0043] Figure 2 shows an enlarged view of the protection device 1.

[0044] The first current source S1 comprises a first transistor T1 connected to the first terminal L1. The first transistor T1 comprises: - a first terminal T11 connected to the first terminal L1 of the generation channel L1-L2, - a second terminal T12 also connected to the first terminal L1 of the generation channel L1-L2, - and a third terminal T 13 connected to the second current source S2.

[0045] The first transistor T1 is a power IGBT transistor. It can also be considered that the first transistor T1 is a bipolar transistor. Therefore, the first terminal T11 of the bipolar transistor is then a collector, the second terminal T12 of the bipolar transistor is then a base and the third terminal T13 of the bipolar transistor is an emitter.

[0046] It can also be considered that the first transistor T1 is a MOS type transistor. Therefore, the first terminal T11 of the MOS transistor is then a drain, the second terminal T12 of the MOS transistor is then a gate and the third terminal T13 of the MOS transistor is a source.

[0047] The first current source S1 also comprises a first diode 31 arranged between the first terminal T11 of the first transistor T1 and the third terminal T13 of the first transistor T1. In other words, the first diode 31 comprises a cathode 311 connected to the first terminal T11 of the first transistor T1 and an anode 312 connected to the third terminal T13 of the first transistor T1.

[0048] Thus, as previously stated, when the direction of the current is from the first terminal L1 to the second terminal L2, then the current from the first terminal L1 only passes through the power transistor T1 which is on since the first diode 31, and more precisely the cathode 311 is blocked.

[0049] Thus, in order to be able to detect the possible overvoltage in the generation channel L1 - L2 and in the channel 10, the protection device 1 comprises a first overvoltage detector 21 configured to detect an overvoltage level OvH between the first terminal L1 and the second terminal L2 of the generation channel L1 - L2. The overvoltage level OvH is a voltage value between the first terminal L1 and the second terminal L2 of the generation channel L1 - L2 greater than a first voltage value V haut predefined threshold. As an indicative example, the first voltage value V haut threshold can be 200 Volts for a generation of 115 Vac.

[0050] The first overvoltage detector 21 is arranged to measure the voltage between the first terminal L1 and the second terminal T12 of the first transistor T1. It may also be envisaged that the first overvoltage detector 21 is arranged to measure the voltage between the first terminal L1 and the first terminal T11 of the first transistor T1.

[0051] Furthermore, the first current source S1 comprises a first resistor R1 so as to make it possible to know the electrical potential between the first terminal L1 and the second terminal L2 in the electrical generation channel L1-L2. It may be envisaged, in a preferred configuration, that the first overvoltage detector 21 is connected to the first resistor R1 in order to facilitate the measurement of the voltage in the channel 10.

[0052] The first current source S1 also comprises a first current regulating device 41 connected to the first overvoltage detector 21 and configured to regulate the current flowing through the first transistor T1 to a current value proportional to the voltage present between the first terminal L1 and the second terminal L2, with a maximum value of 20 amps for example.

[0053] In addition, the first current source S1 comprises a first activation device 51 of the first regulation device 41 connected to the first overvoltage detector 21 configured to switch from a deactivated state, in which the first regulation device 41 is inactive, to an activated state, in which the first regulation device 41 is active, when the first overvoltage detector 21 detects the overvoltage level OvH. In other words, the first activation device 51 of the first regulation device 41 is a state device configured to switch between two states: an activated state and a deactivated state.

[0054] When the first activation device 51 of the first regulation device 41 is in the activated state, then the first activation device 51 allows the first regulation device 41 to regulate the current flowing through the first current source S1 and the channel 10 from the first terminal L1 to the second terminal L2. And, when the first activation device 51 of the first regulation device 41 is in the deactivated state, then the first activation device 51 blocks the first regulation device 41 in its regulation of the current in the channel 10 from the first terminal L1 to the second terminal L2 so that the first current source S1 and, more particularly the first regulation device 41, does not apply regulation in the channel 10.Therefore, the first activation device 51 of the first regulation device 41 switches to an activated state when the first overvoltage detector 21 detects the overvoltage level OvH and to the deactivated state when no overvoltage is detected by the first overvoltage detector 21.

[0055] The first activation device 51 comprises a first auxiliary voltage detector 61 configured to determine a voltage value between the first terminal L1 and the second terminal L2 of the generation channel L1-L2. More specifically, the first auxiliary voltage detector 61 may be configured to measure the voltage between the second terminal T12 of the first transistor T1 and the second terminal L2. To do this, a first auxiliary resistor R1' may be positioned between the second terminal T12 of the first transistor T1 and the second terminal L2 so as to allow the first auxiliary voltage detector 61 to measure the voltage across the first auxiliary resistor R1'. In other words, the first resistor auxiliary R1 ' makes it possible to give an image of the voltage between the second terminal T12 of the first transistor T1 and the second terminal L2. The first auxiliary voltage detector 61 thus makes it possible to generate a first condition C1 at the flip-flop of the first activation device 51 of the first regulation device 41 between the activated state and the deactivated state. This first flip-flop condition C1 is interpreted as the measurement of a voltage by the first auxiliary voltage detector 61 whose absolute value is less than a second voltage value V nom predefined threshold. As an indicative example, the second voltage value V nom threshold can be 170 Volts for a generation of 115 Vac.

[0056] The first current source S1 may also comprise a first regulating resistor R1” configured to measure the electrical potential between the first terminal L1 and a terminal C located between the first current source S1 and the second current source S2. This first regulating resistor then makes it possible to generate a proportionality between the measurable voltage between the first terminal L1 and this terminal C and the current flowing through the first current source S1.

[0057] The first activation device 51 also comprises a first current detector 71 arranged between the third terminal T13 of the first transistor T1 and the second current source S2 and configured to determine a current value at the third terminal T13 of the first transistor T1. The first current detector 71 thus makes it possible to have a reliable measurement of the current at the output of the first transistor T1. The first current detector 71 thus makes it possible to generate a second condition C2 at the flip-flop of the first activation device 51 of the first regulation device 41 between the activated state and the deactivated state. This second flip-flop condition C2 is interpreted as the measurement of a current by the first current detector 71 of zero at the output of the first transistor T1. It may be envisaged that the first current detector 71 is connected to a first transistor resistor R1. igbtconnected to the third terminal T13 of the first transistor T1. The first transistor resistor Rl igbt is a low value resistor allowing to give an image of the current passing through the first current source S1.

[0058] Thus, the first activation device 51 is configured to switch from the activated state to the deactivated state when the voltage value determined by the first auxiliary voltage detector 61 is lower than the second voltage value V nom predefined and when the current value determined by the first current detector 71 is zero. In other words, the first activation device 51 can only switch from the activated state to the deactivated state when the first condition C1 and the second condition C2 are both met. Therefore, when the first condition C1 and the second condition C2 are met, then the first regulation device 41 is inactive, thus reflecting a nominal operating state in the electrical generation channel L1-L2 and in the channel 10 and an absence of overvoltage.

[0059] Conversely, the only condition allowing the first activation device 51 of the first regulation device 41 to switch from the inactivated state to the activated state is the detection of a voltage value by the first overvoltage detector 21 greater than the first voltage value V hautthreshold and therefore an OvH overvoltage level. From then on, the first regulation device 41 is active, thus reflecting a state of malfunction in the electrical generation channel L1 -L2 and in channel 10 and the presence of an overvoltage.

[0060] In fact, the presence of a voltage measurement lower than the second voltage value V nom threshold thus makes it possible to highlight the fact that the voltage between the first terminal L1 and the second terminal L2 makes it possible not to degrade the components between the first terminal L1 and the second terminal L2. And, the presence of a cancellation of the current between the output of the first transistor T1 thus reflects an inversion of the direction of the current between the first terminal L1 and the second terminal L2.

[0061] And, similarly, the second current source S2 comprises a second transistor T2 connected to the second terminal L2. The second transistor T2 comprises: - a first terminal T21 connected to the second terminal L2 of the generation channel L1-L2, - a second terminal T22 also connected to the second terminal L2 of the generation channel L1-L2, - and a third terminal T23 connected to the first current source S1.

[0062] The second transistor T2 is a power transistor. It can also be considered that the second transistor T2 is a bipolar transistor. Therefore, the first terminal T21 of the bipolar transistor is then a collector, the second terminal T22 of the bipolar transistor is then a base and the third terminal T23 of the bipolar transistor is an emitter.

[0063] It can also be considered that the second transistor T2 is a MOS type transistor. Therefore, the first terminal T21 of the MOS transistor is then a drain, the second terminal T22 of the MOS transistor is then a gate and the third terminal T23 of the MOS transistor is a source.

[0064] The second current source S2 also comprises a second diode 32 disposed between the first terminal T21 of the second transistor T2 and the third terminal T23 of the second transistor T2. In other words, the second diode 32 comprises a cathode 321 connected to the first terminal T21 of the second transistor T2 and an anode 322 connected to the third terminal T23 of the second transistor T2.

[0065] Thus, when the direction of the current is from the second terminal L2 to the first terminal L1, then the current from the second terminal L2 only passes through the second transistor T2 which is conducting since the second diode 32 is blocking. More precisely, when the current is directed from the first terminal L1 to the second terminal L2, then the current passes through the first transistor T1 which is conducting, while the first diode 31 is blocking, then the second diode 32 which is conducting, while the second transistor T2 is blocking, before arriving at the level of the second terminal L2. Conversely, when the current is directed from the second terminal L2 to the first terminal L1, then the current passes through the second transistor T2 which is conducting, while the second diode 32 is blocking, then the first diode 31 which is conducting, while the first transistor T1 is blocking, before arriving at the level of the first terminal L1.

[0066] Thus, in order to be able to detect the possible overvoltage in the generation channel L1 -L2 and in the channel 10 when the current is directed from the second terminal L2 to the first terminal L1, the protection device 1 comprises a second overvoltage detector 22 configured to detect a second overvoltage level OvH' between the second terminal L2 and the first terminal L1 of the generation channel L1 -L2. The second overvoltage level OvH' is a voltage value between the second terminal L2 and the first terminal L1 of the generation channel L1 -L2 greater than a third voltage value V' haut predefined threshold. As an indicative example, the third voltage value V' haut threshold may be -200 Volts for a generation of 115 Vac. Indeed, the voltage being measured from the second terminal L2 to the first terminal L1, the voltage is negative compared to the electrical generation channel L1 -L2.

[0067] According to a preferred configuration, the first overvoltage detector 21 and the second overvoltage detector 22 are included in a single overvoltage detector comprising different voltage measurement sensors at the level of the first transistor T1 and the second transistor T2. This configuration has the advantage of making it possible to limit the size in the protection device 1.

[0068] Furthermore, it can also be considered that the absolute value of the third voltage value V' haut threshold is identical to the absolute value of the first voltage value V hautthreshold so that the single overvoltage detector is configured to measure the absolute value of the voltage in the electrical generation channel L1 -L2, regardless of the direction of the current. Therefore, the absolute value of the overvoltage level OvH is identical to the absolute value of the second overvoltage level OvH' so that the voltage is estimated as acceptable when the measurement of the voltage value by the single overvoltage detector or by the first overvoltage detector 21 or by the second overvoltage detector 22 is between the first voltage value V haut threshold and the third voltage value V' haut threshold.

[0069] The second overvoltage detector 22 is arranged to measure the voltage between the second terminal L2 and the second terminal T22 of the second transistor T2. It may also be envisaged that the second overvoltage detector 22 is arranged to measure the voltage between the second terminal L2 and the first terminal T21 of the second transistor T2.

[0070] Furthermore, the second current source S2 comprises a second resistor R2 so as to make it possible to know the electrical potential between the first terminal L1 and the second terminal L2 in the electrical generation channel L1-L2. It may be envisaged, in a preferred configuration, that the second overvoltage detector 22 is connected to the second resistor R2 in order to facilitate the measurement of the voltage in the channel 10.

[0071] It can also be envisaged, as mentioned previously, that the single overvoltage detector is connected to the first resistor R1 and to the second resistor R2.

[0072] The second current source S2 also comprises a second current regulating device 42 connected to the second overvoltage detector 22 and configured to limit the current flowing through the second transistor T2 to a predefined current value, with a maximum value of 20 amperes for example. According to a preferred configuration, the second regulating device 42 is arranged between the second resistor R2 and the second terminal T22 of the second transistor T2. However, any other arrangement can be envisaged as long as the second current regulating device 42 is connected to the second overvoltage detector 22.

[0073] Alternatively, the first regulation device 41 and the second regulation device 42 can be included in a single regulation device making it possible to limit the space requirement in the protection device 1.

[0074] In addition, the second current source S2 comprises a second activation device 52 of the second regulation device 42 connected to the second overvoltage detector 22 configured to switch from a deactivated state, in which the second regulation device 42 is inactive, to an activated state, in which the second regulation device 42 is active, when the second overvoltage detector 22 detects the second overvoltage level OvH'. In other words, the second activation device 52 of the second regulation device 42 is a state device configured to switch between two states: an activated state and a deactivated state.

[0075] When the second activation device 52 of the second regulating device 42 is in the activated state, then the second activation device 52 enables the second regulating device 42 to regulate the current flowing through the second current source S2 and the channel 10 from the second terminal L2 to the first terminal L1. And, when the second activation device 52 of the second regulating device 42 is in the deactivated state, then the second activation device 52 blocks the second regulating device 42 from regulating the current in the channel 10 from the second terminal L2 to the first terminal L1 so that the second current source S2 and, more particularly, the second regulation device 42, does not apply regulation in the channel 10. Therefore, the second activation device 52 of the second regulation device 42 switches to an activated state when the second overvoltage detector 22 detects the second overvoltage level OvH' and to the deactivated state when no overvoltage is detected by the second overvoltage detector 22.

[0076] The second activation device 52 comprises a second auxiliary voltage detector 62 configured to determine a voltage value between the second terminal L2 and the first terminal L1 of the generation channel L1-L2. More specifically, the second auxiliary voltage detector 62 can be configured to measure the voltage between the second terminal T22 of the second transistor T2 and the first terminal L1. To do this, a second auxiliary resistor R2' can be positioned between the second terminal T22 of the second transistor T2 and the first terminal L1 so as to allow the second auxiliary voltage detector 62 to measure the voltage across the second auxiliary resistor R2'. In other words, the second auxiliary resistor R2' makes it possible to give an image of the voltage between the second terminal T22 of the second transistor T2 and the first terminal L1.The second auxiliary voltage detector 62 thus also makes it possible to generate the first condition C1 at the switchover of the second activation device 52 of the second regulation device 42 between the activated state and the deactivated state. And, similarly, the first switchover condition C1 is interpreted as the measurement of a voltage by the second auxiliary voltage detector 62 whose absolute value is lower than the second voltage value V. nom predefined threshold.

[0077] The second current source S2 may also comprise a second regulating resistor R2” configured to measure the electrical potential between the second terminal L2 and the terminal C located between the first current source S1 and the second current source S2. This second regulating resistor R2” then makes it possible to generate a proportionality between the measurable voltage between the second terminal L2 and this terminal C and the current flowing through the second current source S1.

[0078] The second activation device 52 also comprises a second current detector 72 disposed between the third terminal T23 of the second transistor T2 and the first current source S1 and configured to determine a value of current at the third terminal T23 of the second transistor T2. The second current detector 72 thus makes it possible to have a reliable measurement of the current at the output of the second transistor T2. It can be envisaged that the second current detector 72 is connected to a second transistor resistor R2 igbt connected to the third terminal T23 of the second transistor T2. The second transistor resistor R2 igbtis a low-value resistor making it possible to give an image of the current flowing through the second current source S2. The second current detector 72 thus makes it possible to generate the second condition C2 at the flip-flop of the second activation device 52 of the second regulation device 42 between the activated state and the deactivated state. Similarly, the second flip-flop condition C2 is interpreted as the measurement of a current by the second current detector 72 being zero at the output of the second transistor T2. Therefore, the second condition C2 is active when a current measurement equal to zero is observed between the first transistor T1 and the second transistor T2, reflecting a reversal of the direction of the current between the first transistor T1 and the second transistor T2.

[0079] Thus, the second activation device 52 is configured to switch from the activated state to the deactivated state when the absolute value of the voltage determined by the second auxiliary voltage detector 62 is less than the second voltage value V nomand when the current value determined by the second current detector 72 is zero. In other words, the second activation device 52 can only switch from the activated state to the deactivated state when the first condition C1 and the second condition C2 are both met, the validations of these two conditions, namely the first condition C1 and the second condition C2, being respectively transmitted by the second auxiliary voltage detector 62 and by the second current detector 72. Conversely, the first activation device 51 switches from the activated state to the inactivated state only when the first condition C1 and the second condition C2 are both met, the validations of these two conditions, namely the first condition C1 and the second condition C2, being respectively transmitted by the first auxiliary voltage detector 61 and by the second current detector 71.

[0080] Therefore, when the first condition C1 and the second condition C2 are met, then the second regulation device 42 is inactive, thus translating a nominal operating state in the electrical generation channel L1-L2 and in channel 10 and an absence of overvoltage.

[0081] Conversely, the only condition allowing the second activation device 52 of the second regulation device 42 to switch from the inactivated state to the activated state is the detection of an absolute voltage value by the second overvoltage detector 22 greater than the first voltage value V haut threshold and therefore an overvoltage level OvH. In other words, the second regulation device 42 can switch from the inactivated state to the activated state only if the voltage value measured by the second overvoltage detector 22 is lower than the third voltage value V' haut threshold, in the case where || V' haut || = ||VhaMt ||.

[0082] From then on, the second regulation device 42 is active, thus reflecting a state of malfunction in the electrical generation channel L1-L2 and in the channel 10 and the presence of an overvoltage.

[0083] Furthermore, the protection device 1 may also comprise an opening device 8 for the protection device 1. This opening device 8 provides a function of protecting the generation channel L1-L2 with respect to a possible overvoltage generated by the protection device 1 following a malfunction of the first current source S1 or the second current source S2. The opening device 8 is thus configured to open the channel 10 so as to no longer allow transmission of current in the channel 10.

[0084] As an indicative example, the opening device 8 may be a controlled switch, a circuit breaker or, according to a preferred aspect, a fuse.

[0085] The opening device 8 can be positioned randomly in the channel 10, that is to say between the first terminal L1 and the first source S1, or between the first source S1 and the second source S2 or between the second source S2 and the second terminal L2.

[0086] Figure 3 thus represents a structural view of the protection device 1. Thus, it can be envisaged that the first overvoltage detector 21, the first auxiliary voltage detector 61, the first current detector 71 and the first current regulating device 41 are operational amplifiers. And, in an identical manner, the second overvoltage detector 22, the second auxiliary voltage detector 62, the second current detector 72 and the second current regulating device 42 may also be operational amplifiers. Alternatively, a set of transistors may be considered.

[0087] Thus, the assembly comprising the opening device 8, first current source S1 and second current source S2, forming the channel 10 in particular, thus form a first protection unit 1'. Therefore, it can be envisaged that the protection device 1 comprises a plurality of protection units, as shown in FIG. 4 with a second additional protection unit 1" and a n ième additional protection unit l n .

[0088] Each additional protection unit thus comprises a structure equivalent to the first protection unit 1', that is to say that each additional protection unit comprises a first additional current source S3 identical to the first current source S1, a second additional current source S4 identical to the second current source S2 and an additional opening device 8'. And, as in the first protection unit 1', the first additional current source S3 is in an opposite direction to the second additional current source S4.

[0089] Each additional 1” protection unit to the n is arranged in bypass of the first protection unit 1' and the electrical generation channel L1 -L2 so as to regulate the current effectively and limit any detected overvoltage.

[0090] Indeed, the overvoltage generated between the first terminal L1 and the second terminal L2 has a defined energy. The use of several protection units, comprising the first protection unit 1 ' as shown in figures 1 to 3, and one or more additional protection units 1 ” to the n , has the advantage of distributing the absorption of the energy generated by this overvoltage over several channels without adding a component dedicated to this absorption. Thus, as an indicative example, for an overvoltage generating an energy equivalent to a value of one hundred watts, it is possible to envisage the use of a single protection unit 1 '. And, for an overvoltage generating, for example, an energy equivalent to a value of approximately two hundred watts, it can then be envisaged to add an additional protection unit 1 ”. The protection device 1 then comprises two units protection 1' and 1” connected in parallel to each other and also in parallel to the electrical generation channel L1 -L2.

[0091] Furthermore, the use of several additional protection units also has the advantage of allowing the protection device 1 to operate even if one of the additional protection units is not functioning correctly and it is necessary to open the channel of the defective additional protection unit by means of the additional opening device 8' of the defective additional protection unit.

[0092] Furthermore, in the case of operation of an electrical machine in several phases, as shown in Figure 5, it can be envisaged that each phase comprises a set of one or more protection units in order to protect each phase of the electrical machine against a possible overvoltage. Thus, a first phase N1 formed between the first terminal L1 and the second terminal L2 can comprise a first protection set P1 formed by the first protection unit 1 ' and possibly one or more additional protection units 1 ” to the n . And, for a second phase N2 of the electrical machine formed between the second terminal L2 and a third terminal L3, it may also be envisaged to incorporate a second protection assembly P2 formed by a second main protection unit 2' and possibly one or more additional protection units 2” to 2 n. And, similarly, each phase Nx formed between two terminals can include an identical protection assembly Px.

[0093] Figure 6 represents a chronogram of the evolution over time of an overvoltage detected by the protection device 1.

[0094] The first line of this timing diagram represents the voltage measured by the first overvoltage detector 21 or by the second overvoltage detector 22, depending on the direction of the current, as well as by the first auxiliary voltage detector 61 or by the second auxiliary voltage detector 62, depending on the direction of the current, in the electrical generation channel L1 -L2 between the first load L1 and the second load L2. On this first line of the timing diagram is also represented the first voltage value V haut threshold for detecting an OvH overvoltage level and the second voltage value V nom threshold allowing to detect a nominal voltage value and the end of the measured overvoltage.

[0095] Thus, as shown on the first line of the timing diagram, an overvoltage is detected with a voltage measurement, by the first overvoltage detector 21 or by the second overvoltage detector 22, depending on the direction of the current, greater than the first voltage value V haut threshold.

[0096] The second line of the timing diagram of Figure 6 is a binary representation of the cancellation of the current measured by the first current detector 71 or by the second current detector 72 in the protection device 1, and more particularly in the channel 10. More precisely, this signal is a square wave representation, each edge of which represents a cancellation of the current in the channel 10, thus making it possible to be in agreement with the second condition C2 in order to allow the switching of the first activation device 51 of the first regulation device 41 or of the second activation device 52 of the second regulation device 42 between the activated state and the deactivated state. Therefore, the second condition C2 is respected at each edge of the square wave.

[0097] The third line of the timing diagram is also a binary representation of the detection by the first auxiliary voltage detector 61 or the second auxiliary voltage detector 62, depending on the direction of the current, of a voltage lower than the second voltage value V nom threshold. More precisely, the binary signal is in a high position when the voltage measured by the first auxiliary voltage detector 61 or the second auxiliary voltage detector 62 is lower than the second voltage value V nom threshold and in a low position when the measured voltage is higher than the second voltage value V nomthreshold. In other words, the third line of this timing diagram is a binary representation of compliance with the first condition C1 allowing the first activation device 51 of the first regulation device 41 or the second activation device 52 of the second regulation device 42 to switch between the activated state and the deactivated state. Therefore, the first condition C1 is respected when the signal is in its high position.

[0098] Thus, the second line and the third line of the timeline in Figure 6 are graphical representations of the cumulative conditions, namely the first condition C1 and the second condition C2 allowing the first activation device 51 of the first regulation device 41 or the second activation device 52 of the second regulation device 42 to switch between the activated state and the deactivated state. Therefore, the second condition C2 is respected at each edge of the square wave. Therefore, this switch between the activated state and the deactivated state takes place when simultaneously, an edge is detected in the square wave signal of the second line and the signal of the third line is in its high position.

[0099] The fourth line of the timing diagram of Figure 6 represents the detection of an overvoltage level OvH by the first overvoltage detector 21 or by the second overvoltage detector 22, depending on the direction of the current in the electrical generation channel L1-L2. This detection is done by means of a binary representation in which a high position represents a detected overvoltage and a low position represents the absence of an overvoltage detection. Therefore, the switch from the inactivated state to the activated state of the first activation device 51 of the first regulation device 41 or of the second activation device 52 of the second regulation device 42 is done when this overvoltage level is detected, that is to say when the signal switches to the high position.

[0100] The fifth line of the timing diagram of Figure 6 then represents the duration during which the first activation device 51 of the first regulation device 41 or the second activation device 52 of the second regulation device 42 is in the activated state or in the deactivated state. More precisely, this binary representation makes it possible to indicate that when the signal is in a high position, then the first activation device 51 of the first regulation device 41 or the second activation device 52 of the second regulation device 42 is in the activated state following detection of an overvoltage whereas when the signal is in a low position, then the first activation device 51 of the first regulation device 41 or the second activation device 52 of the second regulation device 42 is in the deactivated state following the simultaneous detection of the first condition C1 and the second condition C2.

[0101] Finally, the fifth line of the timing diagram in Figure 6 represents the value of the voltage between the first terminal L1 and the second terminal L2 following an overvoltage, highlighting the limitation of the overvoltage detected over a reduced time by means of the protection device 1.

[0102] Figures 7A and 7B thus present waveforms associated with the voltage measured in the electrical generation channel L1 -L2 crossed by an alternating current. More precisely, Figure 7A presents a situation in which the electrical generation channel L1 -L2 operates without input from the protection device while Figure 7B represents a situation in which the electrical generation channel L1 -L2 is supplemented, in the event of an overvoltage, by the protection device 1.

[0103] Therefore, the protection device 1 makes it possible to limit any overvoltage peak detected beyond the thresholds V haut and V' hautso as not to impact the electrical components present in the L1-L2 electrical generation channel.

[0104] The proposed protection device 1 therefore aims, by a single means, to overcome rapid and slow overvoltages without distortion and without reducing the available power of the electrical network. The modularity of this means makes this protection function available and adaptable to the more or less significant energies to be absorbed.

[0105] This protection device 1 is characterized by: - its speed, less than a microsecond, for impulsive surges called “fast”, - its low distortion, less than 2%, for so-called "slow" overvoltages, i.e. at the frequency of electrical generation, i.e. for frequency ranges of approximately 50 / 60Hz, 400 / 800 Hz for example, - its ability to clip positive and negative overvoltages independently, - without impact on the available power of the generation channel, i.e. with disconnection of the protection when the overvoltage is within the desired gauge, - without generating a surge itself when disconnected, - unique protection that protects against both rapid and slow surges, - redundancy to ensure the availability of the protection function, - modularity allowing the protection device 1 to be adapted to the energy to be absorbed depending on the overvoltage and the more or less significant time in the generation channel, - the presence of a safety device, i.e. an element which opens if the protection function is short-circuited, - its ability to carry out automatic regulation to guarantee the availability of the protection function.

Claims

CLAIMS 1. Electrical energy generator (100) configured to generate electrical energy to a load (CH) via an alternating current generation channel (L1-L2), the electrical energy generator (100) comprising a fast overvoltage and slow overvoltage protection device (1) arranged in parallel with the alternating current generation channel (L1-L2), the protection device (1) comprising: - A first current source (S1) comprising an input (S11) and an output (S12), the input (S11) of the first current source (S1) being connected to a first terminal (L1) of the generation channel, - A second current source (S2) comprising an input (S21) and an output (S22), the input (S21) of the second current source (S2) being connected to a second terminal (L2) of the generation channel, the output (S22) of the second current source (S2) being connected to the output (S12) of the first current source (S1).

2. Overvoltage protection device (1) according to claim 1, wherein the first current source (S1) and / or the second current source (S2) are configured to generate a current proportional to a voltage measurable at the first current source (S1) or at the second current source (S2).

3. An electrical energy generator (100) according to claim 1 or claim 2, wherein the overvoltage protection device (1) comprises an overvoltage detector (21-22) configured to detect an overvoltage level between the first terminal (L1) and the second terminal (L2) of the generation channel (L1-L2), the overvoltage level being a voltage value between the first terminal (L1) and the second terminal (L2) of the generation channel (L1-L2) greater than a first predefined threshold voltage value.

4. Electric power generator (100) according to claim 3, wherein the first current source (S1) comprises: - a first transistor (T 1 ), the first transistor (T 1 ) comprising: o a first terminal (T11 ) connected to the first terminal (L1 ) of the generation channel (L1 -L2), o a second terminal (T12) connected to the first terminal (L1 ) of the generation channel (L1 -L2), o a third terminal (T13) connected to the second current source (S2), - a first diode (31) comprising a cathode (311) connected to the first terminal (T11) of the first transistor (T1) and an anode (312) connected to the third terminal (T13) of the first transistor (T1), - a first resistor (R1) arranged between the first terminal (L1) of the generation channel (L1-L2) and the second terminal (T12) of the first transistor (T1) and connected to the overvoltage detector (21-22), - a first current regulating device (41) connected to the overvoltage detector (21-22), arranged between the first resistor (R1) and the second terminal (T12) of the first transistor (T1) and configured to limit the current flowing through the first transistor (T1) to a predefined current value.

5. An electrical energy generator (100) according to claim 4, wherein the first current source (S1) comprises a first activation device (51) of the first regulation device (41) connected to the overvoltage detector (21-22) configured to switch from a deactivated state, in which the first regulation device (41) is inactive, to an activated state, in which the first regulation device (41) is active, when the overvoltage detector (21-22) detects the overvoltage level, the first activation device (51) comprising: - A first auxiliary voltage detector (61) configured to determine a voltage value between the first terminal (L1) and the second terminal (L2) of the generation channel (L1-L2), - A first current detector (71) arranged between the third terminal (T13) of the first transistor (T1) and the second current source (S2) configured to determine a current value at the third terminal (T13) of the first transistor (T1), the first activation device (51) being configured to switch from the activated state to the deactivated state when the voltage value determined by the first auxiliary voltage detector (61) is less than a second predefined voltage value and when the current value determined by the first current detector (71) is zero.

6. Electric power generator (100) according to claim 3, wherein the second current source (S2) comprises: - a second transistor (T2), the second transistor (T2) comprising: o a first terminal (T21) connected to the second terminal (L2) of the generation channel (L1-L2), o a second terminal (T22) connected to the second terminal (L2) of the generation channel (L1-L2), o a third terminal (T23) connected to the first current source (S1), - a second diode (32) comprising a cathode (321) connected to the first terminal (T21) of the second transistor (T2) and an anode (322) connected to the third terminal (T23) of the second transistor (T2), - a second resistor (R2) arranged between the second terminal (L2) of the generation channel (L1-L2) and the second terminal (T22) of the second transistor (T2) and connected to the overvoltage detector (21-22), - a second current regulating device (42) connected to the overvoltage detector (2), arranged between the second resistor (R2) and the second terminal (T22) of the second transistor (T2) and configured to limit the current flowing through the second transistor (T2) to a predefined current value.

7. An electrical energy generator (100) according to claim 6, wherein the second current source (S2) comprises a second activation device (52) of the second regulation device (42) connected to the overvoltage detector (21-22) configured to switch from a deactivated state, in which the second regulation device (42) is inactive, to an activated state, in which the second regulation device (42) is active, when the overvoltage detector (21-22) detects the overvoltage level, the second activation device (52) comprising: - A second auxiliary voltage detector (62) configured to determine a voltage value between the first terminal (L1) and the second terminal (L2) of the generation channel (L1-L2), - A second current detector (72) arranged between the third terminal (T32) of the second transistor (T2) and the first current source (S1) configured to determine a current value at the third terminal (T32) of the second transistor (T2), the second activation device (52) being configured to switch from the activated state to the deactivated state when the voltage value determined by the second auxiliary voltage detector (62) is less than a third predefined voltage value and when the current value determined by the second current detector (72) is zero.

8. Electrical energy generator (100) according to one of claims 4 or 5, in which the first transistor (T1) is a bipolar transistor.

9. Electrical energy generator (100) according to one of claims 6 or 7, in which the second transistor (T2) is a bipolar transistor.

10. Electric energy generator (100) according to one of the preceding claims, in which the protection device (1) comprises an opening device (8) for the protection device.

11. Electric power generator (100) according to one of the preceding claims, wherein the protection device (1) comprises a first protection unit, the first protection unit comprising the first current source (S1) and the second current source (S2), the protection device (1) comprising at least one additional protection unit comprising a first additional current source (S3) identical to the first current source (S1) and a second additional current source (S4) identical to the second current source (S2), the at least one additional protection unit being arranged in bypass of the first protection unit.

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