A method for crossing a neutral zone of an electrical power system by an electric vehicle, consisting of at least two units; associated electric vehicle

Abstract

A method for crossing a neutral zone of an electrical power system by an electric vehicle consisting of at least two units; associated electric vehicle. This method is carried out by an electric vehicle, each unit of which comprises: a motor; a contact shoe (11, 13, 14, 16) collecting external electrical power; and a battery delivering internal electrical power, each unit being in an operating mode selected from a primary mode in which the motor uses external electrical power; and at least one alternative mode in which the motor does not use external electrical power.For crossing the neutral zone (24), when at least one unit of the vehicle (10) detects that it is unable to collect external electrical power, said at least one unit switches to alternating current mode and transmits information indicating this switchover to the other units of the vehicle. Upon receiving this information, each of the other units switches to said alternating current mode. (See Figure 2 for abbreviations.)

Description

Title of the invention: Method for crossing by an electric vehicle consisting of at least two units of a neutral zone of an electrical power supply system; associated electric vehicle.

[0001] The invention relates to the field of electric vehicles, in particular guided electric vehicles (such as trams), capable, during their movement, of capturing electrical power from an electrical supply system.

[0002] Electrical power supply systems for moving vehicles are well known. For example, ground-based power supply systems are known, which include a power supply rail made up of a plurality of segments arranged end to end along the longitudinal direction of the roadway.

[0003] The plurality of segments consists of an alternation of conducting segments and insulating segments.

[0004] Control means allow the state of switches to be controlled in order to selectively supply the conductive segments of the supply rail when a vehicle passes over them.

[0005] The electric vehicle moves on the road. It is advantageously equipped with two contactors, so that at least one contactor is in contact with a conductive segment at every instant, this conductive segment being supplied so that the electric vehicle can capture electrical power by conduction from the ground.

[0006] However, in certain situations, the distance between two consecutive conductive segments along the direction of travel of the vehicle is too great for at least one of the contact strips to be in contact with a conductive segment. This is generally referred to as a neutral zone of the electrical supply system.

[0007] This is the case, for example, when the switches associated with one or more successive conductive segments malfunction so that the corresponding conductive segments can no longer be powered when a vehicle passes over them.

[0008] This is also the case at singular points, such as a track switch or a crossing between the roadway on which the electric vehicle travels and a road used, for example, by automobiles.

[0009] In the latter case, to avoid premature wear of the feed rail segments and consequently a greater number of breakdowns, due to the repeated passage of automobiles, it is recommended to interrupt the feed rail at the crossing, or at least to use only one or more insulating segments to make the feed rail at the crossing.

[0010] Thus, between the upstream and downstream conducting segments provided on either side of a In a neutral zone, the electric vehicle cannot draw any electrical power from the ground-based power supply system. A neutral zone is therefore an area where the external power supply system to the vehicle (notably the power rail or overhead line) is unable to provide energy to the rail vehicle because it is not powered. A fault in a segment of the power rail, leading to the opening of a power contactor on that rail, can create a neutral zone at that segment within the power supply system.

[0011] However, in the case where the electric vehicle consists of the coupling of at least two units, crossing such a neutral zone presents the following disadvantages.

[0012] Figure 1 shows seven successive stages of an electric vehicle 10 crossing a neutral zone 24 of a power rail 20 of a ground-based power supply system. On either side of the neutral zone 24, the power rail 20 is made up of insulating segments 22 and conductive segments 21, 23, 25, the conductive segment 23 being the conductive segment upstream of the neutral zone 24 and the conductive segment 25 being the conductive segment downstream of the neutral zone 24, according to the direction of travel of the electric vehicle 10, which is indicated by the arrow V.

[0013] The vehicle 10 consists of two units, 11 and 12, mechanically coupled to each other. These units are advantageously identical to each other. They are powered and each capable of collecting electrical energy from the supply rail 20 by means of at least one, or even a pair, of contact shoes, respectively 13 and 15 for unit 11 and 14 and 16 for unit 12.

[0014] At the first stage 110, the vehicle 10 is located upstream of the neutral zone 24. The pair of brushes equipping each of the units 11 and 12 of the vehicle allows them to capture energy from the conductive segments 21 which are properly powered by the passage of the vehicle 10. Each unit then operates in a mode in which the electric motors of a unit operate in traction using the power captured from the ground supply system.

[0015] In the second stage 120, when the head unit 11 enters the neutral zone 24, these contact shoes, 13 and 15, can no longer receive power from the ground power supply system. Thus, the motors of the head unit 11 cease to operate in traction. However, at the same time, the tail unit 12 continues to be able to draw electrical power from the ground power supply system, so its motors continue to operate in traction. Consequently, the head unit 11 decelerates, sometimes abruptly, before being pushed by the tail unit 12. Thus, upon entering the neutral zone 24, the vehicle is jolted.

[0016] In the third stage 130, the vehicle 10 moves forward onto the neutral zone 24, the head unit 11 being pushed by the tail unit 12, which is the only driving unit.

[0017] At the fourth step 140, the head unit crossed the neutral zone 24 and its wipers reach the downstream conductive segment 25 so that this unit can again operate in traction.

[0018] At the fifth stage 150, the tail unit 12 enters the neutral zone 24. Its contact shoes, 14 and 16, no longer able to receive electrical power from the ground, cause its motors to cease traction. However, at the same time, the head unit 11 continues to be able to draw electrical energy from the ground power supply system, so its motors continue to operate in traction. Consequently, the tail unit 12 decelerates and is pulled by the head unit. Thus, the vehicle is jolted by a further shock.

[0019] At the sixth stage 160, the vehicle 10 continues its movement, the tail unit being passive and towed by the head unit 11, whose engines, powered from the ground, operate in traction.

[0020] Finally, at the seventh stage 170, the tail unit 12 has passed the neutral zone 24 and its skids, 14 and 16, can again capture electrical power by contact on the downstream conductive segment 25. Both units then both operate again in traction.

[0021] Thus, at least upon each unit entering the neutral zone (and possibly upon each unit exiting this same neutral zone), that is, with each change in the operating mode of a unit, the electric vehicle is jolted, which induces temporary discomfort. These sudden accelerations, or rather these sudden variations in acceleration ("jerk"), can sometimes have more serious consequences, for example, when a passenger standing inside the vehicle loses their balance and falls.

[0022] The object of the present invention is therefore to remedy this problem.

[0023] Thus, the invention relates to a method for crossing, by an electric vehicle consisting of at least two units, a neutral zone of an electrical power supply system, each unit comprising: a motor; at least one collection means suitable for collecting external electrical power from the electrical power supply system; and a battery suitable for delivering internal electrical power, each unit being suitable for operating at the current time in an operating mode selected from a plurality of operating modes, the plurality of operating modes comprising: a main operating mode in which the motor operates using external electrical power;and at least one alternative operating mode in which the motor is not supplied by external electrical power, said method comprising a neutral zone crossing step, in which, when at least one unit of the electric vehicle detects that it is unable to collect external electrical power, said at least one unit switches to the alternative operating mode, and transmits an input; training to each of the other units of the vehicle, said information being indicative of said switchover to the alternative operating mode, and in that, upon receipt of said information, each of said other units switches over to said alternative operating mode, so that at any time, each unit is in the same common operating mode so that the vehicle adopts a homogeneous dynamic.

[0024] According to particular embodiments, the process comprises one or more of the following characteristics taken individually or in all technically possible combinations:

[0025] - during the crossing stage, when all the units of the vehicle electric are in the alternative operating mode and that all the units of the electric vehicle detect that they are able to collect external electrical power, the units are able to communicate with each other to switch into the main operating mode;

[0026] - the crossing step is implemented for crossing an area neutral when the speed of the electric vehicle is greater than a first threshold speed, the first threshold speed being between 2 and 10 km / h, preferably equal to 5 km / h;

[0027] - said main operating mode is a first operating mode and said at least one alternative operating mode includes: a second operating mode, in which the motor is in inhibited traction, the unit moving on its own momentum; and a third operating mode, in which the motor operates in traction using the internal electrical power supplied by the battery;

[0028] - during the crossing step, the alternative operating mode corresponds to the third operating mode if the speed of the electric vehicle is less than a second threshold speed, and the alternative operating mode corresponds to the second operating mode if the speed of the electric vehicle is greater than or equal to the second threshold speed, the second threshold speed being between 15 and 30 km / h, preferably equal to 20 km / h;

[0029] - each unit includes a first clean battery contactor, in a closed state, to connect the battery to auxiliary devices of the unit in question, and wherein when the common operating mode is the second operating mode: the first battery contactor of a unit, which detects that it is capable of collecting external electrical power, is placed in an open state, the auxiliary devices being powered by the external electrical power; and the first battery contactor of a unit, which detects that it is incapable of collecting external electrical power, is placed in a closed state, the auxiliary devices being powered by the internal electrical power;

[0030] - each unit includes a second, separate battery contactor, in a state closed, to connect the battery to the motor and advantageously to auxiliary devices of the unit in question, and in which when the common operating mode is the third operating mode, the second battery contactor is in the closed state and when the common operating mode is the first operating mode the second battery contactor is in an open state.

[0031] The invention also relates to an electric vehicle consisting of at least two units, each unit comprising: a motor; at least one collection means suitable for collecting external electrical power from the electrical supply system; and a battery suitable for delivering internal electrical power, each unit being suitable for operating at the current time in an operating mode selected from a plurality of operating modes, the plurality of operating modes comprising: a main operating mode in which the motor operates in traction using the external electrical power collected by the collection means;and an alternative operating mode in which the motor is not powered by external electrical power, characterized in that said electric vehicle is capable of implementing a crossing method conforming to the preceding method, a communication link being established between the units of the electric vehicle in order to allow the transmission, between a first and a second unit, of information indicative of the operating mode at the current time of the first unit, so that the second unit adapts its operating mode at the current time accordingly, and vice versa.

[0032] Preferably, said vehicle is a guided vehicle, more preferably a tram.

[0033] Preferably, the means for collecting a unit of said electric vehicle includes a contact shoe suitable for making electrical contact with a power rail embedded in the ground of the power supply system.

[0034] The invention and its advantages will be better understood upon reading the following detailed description of a particular embodiment, given solely by way of illustration and not limitation, this description being made with reference to the accompanying drawings in which:

[0035] [fig. 1] Figure 1 represents a first way of crossing a neutral zone of a ground power supply installation by an electric vehicle consisting of two units;

[0036] [fig.2] Figure 2 is a representation of a second way of crossing the zone neutral of figure 1;

[0037] [fig.3] Figure 3 is a representation of a third way of crossing an area neutral of figure 1.

[0038] For clarity, reference numerals have been entered only in the first step of each figure. However, identical objects from one step to the next will be indicated by the same reference numerals.

[0039] The figures represent an electric vehicle 10, preferably a tram, consisting of two units coupled to each other, a head unit 11 and a tail unit 12, considering the direction of movement of the vehicle indicated by arrow V. Alternatively, the vehicle consists of more than two units.

[0040] Preferably, these units are identical to each other.

[0041] A unit comprises one or more traction motors.

[0042] A unit includes various auxiliary devices (air conditioning, lights, etc.). These are the equipment that does not participate in traction.

[0043] A unit comprises one or more contact shoes which, in the lowered position, are designed to make mechanical and electrical contact with the segments of a power supply rail of a ground-based power supply system. Thus, unit 11 comprises contact shoes 13 and 15, and the tail unit 12 comprises contact shoes 14 and 16. The external electrical energy captured from the ground is then suitable for supplying power to the equipment of the unit in question (motor and / or auxiliary devices).

[0044] A unit carries one or more batteries, suitable for storing energy and providing internal electrical energy to the equipment of the unit in question (engine and / or auxiliary devices).

[0045] A unit is equipped with a battery contactor. The contactor allows the battery to be connected to the various equipment of the unit so that the battery temporarily supplements the external power supply.

[0046] The battery then powers either only the auxiliary devices, when traction is inhibited, or the auxiliary devices and the motor, when traction is not inhibited.

[0047] The battery contactor can thus be in two different states: in a first state, the battery contactor is closed so as to electrically connect the batteries to the equipment to be powered; in a second state, the battery contactor is open isolating the batteries from the various equipment of the unit.

[0048] A unit includes a control / command computer, which is designed to control the various components of this unit so that it operates in an operating mode selected from among three possible operating modes:

[0049] In a first operating mode, or main operating mode, the unit is designed to capture electrical power from the ground power supply system, and the motors operate in traction using this captured electrical power. In this first operating mode, the battery contactor is in the open state.

[0050] In a second operating mode, which constitutes an alternative operating mode, the unit no longer draws electrical power from the ground. The unit's motors do not operate in traction mode. Traction is said to be inhibited. The unit then moves using its momentum. In this second operating mode, the battery contactor can be either in the open state, in which case the battery does not power any of the vehicle's onboard components, or in the closed state, in which case the battery powers the auxiliary devices.

[0051] In a third operating mode, which constitutes another alternative operating mode, the unit no longer draws electrical power from the ground, but the motors operate in traction using electrical power supplied by the batteries on board the unit. In this third operating mode, the battery contactor is in the closed state.

[0052] Finally, the vehicle 10 includes a communication link between the on-board computers of each of the units constituting the vehicle, so that a unit can at any time select an operating mode that is consistent with the operating modes of the other units. This link can be wired or wireless.

[0053] In the figures, each operating mode is represented by a specific motif within the rectangle representing a unit. Furthermore, the state of the battery contactor is represented by a frame of specific thickness delimiting the rectangle representing a unit. More precisely, a frame of reduced thickness represents a closed state of the battery contactor, and a frame of increased thickness represents an open state of the battery contactor.

[0054] The method according to the invention preferably combines three ways of crossing a neutral zone depending on the instantaneous speed of the electric vehicle.

[0055] If the speed of the vehicle 10 is less than a first threshold speed, for example equal to 5 km / h, the way of crossing the neutral zone 24 is in accordance with the prior art represented in Figure 1 and presented above.

[0056] If the speed of the vehicle 10 is greater than or equal to the first threshold speed, but less than a second threshold speed, for example equal to 20 km / h, the way of crossing the neutral zone 24 is represented by figure 2.

[0057] Finally, if the speed of the vehicle 10 is greater than or equal to the second threshold speed, the way of crossing the neutral zone 24 is represented by Figure 3.

[0058] Alternatively, the crossing method implements either the second way of crossing the neutral zone and the third way of crossing the neutral zone (which amounts to saying that the first threshold speed is zero), or only the second way of crossing the neutral zone or only the third way of crossing the neutral zone.

[0059] With reference to Figure 1, according to the first method of crossing the neutral zone, The unit that cannot draw energy from the ground is placed in the second operating mode, i.e., in inhibited traction, while the unit that can draw energy from the ground is placed in the first operating mode, its motors operating in traction. This unit then propels the other unit. Advantageously, and as represented in Figure 1 by a reduced-thickness frame, in the second operating mode the battery contactor is in the closed state and the auxiliary devices are powered by the battery while traction is inhibited.

[0060] This first way of crossing the neutral zone 24 is retained when the vehicle 10 has a low speed.

[0061] Indeed, at low speeds, although the train is still subject to jolts, the main risk lies in the train coming to a complete stop in the unpowered zone if the initial speed is insufficient to cross this zone under momentum. Thus, a non-uniform behavior is favored, so that the conservation of traction helps to limit this risk.

[0062] Referring to Figure 2, in the second way of crossing the neutral zone 24, as long as at least one unit of the vehicle cannot capture energy from the ground, all the units of the vehicle are maintained in the third mode of operation, in which traction is provided from the energy stored by the on-board batteries.

[0063] Thus, in the first stage 210, upstream of the neutral zone 24, the two units 11 and 12 of the vehicle 10 are in the first operating mode.

[0064] In the second step 220, when the rear contact shoe 15 of the head unit 11 loses contact with the upstream conduction segment 23, the head unit 11 can no longer collect energy from the ground. Consequently, the head unit 11 switches to the third operating mode. It communicates this change in operating mode to the tail unit 12. The tail unit 12 reacts to this information by also switching to the third operating mode.

[0065] At the third stage 230, as long as at least one of the units cannot capture energy from the ground, all the units remain in the third operating mode.

[0066] In the fourth step 240, when its front wiper 13 makes contact with the downstream conduction segment 25, the head unit 11 can again draw power from the ground. Since at the same time the wipers of the tail unit can still draw energy from the upstream conduction segment 23, both units switch to the first operating mode.

[0067] At the fifth stage 250, when the rear wiper 16 of the tail unit 12 loses contact with the upstream conduction segment 23, the tail unit 12 can no longer be powered from the ground. As a result, the tail unit 12 switches to the third operating mode. It communicates this mode change to the head unit. of operation. The head unit 11 reacts to the reception of this information by switching in turn to the third operating mode.

[0068] In the sixth step 260, as long as at least one of the units cannot capture energy from the ground, all the units remain in the third operating mode.

[0069] Finally, at the seventh stage 270, as soon as the tail unit 12 can capture energy from the ground (that is, when its front wiper 14 comes into contact with the downstream conducting segment 25), the two units switch back into the first operating mode.

[0070] In this second embodiment, when a unit is in the first operating mode, its battery contactor is in the open state, whereas when a unit is in the third operating mode, its battery contactor is in the closed state.

[0071] This second method of crossing the neutral zone has the advantage of using the third operating mode, namely battery traction, as a common mode of operation. Vehicle traction is therefore ensured, as well as passenger comfort due to consistent vehicle behavior.

[0072] However, this method leads to increased stress on the batteries and consequently to premature aging of the batteries.

[0073] Figure 3 illustrates a third way of crossing the neutral zone.

[0074] In a first step 310, upstream of the neutral zone 24, the two units They are in the first operating mode. Their battery contacts are in the open state.

[0075] In the second step 320, as soon as the head unit 11 can no longer collect energy from the ground, it switches to the second operating mode, i.e., inhibited traction. Thus, from this moment on, the head unit 11 operates on momentum. At this moment, the battery contactor of the head unit 11 is switched to the closed state so that the batteries supply power to the auxiliary devices.

[0076] The head unit 11 informs the tail unit 12 of this change in operating mode. In response, the tail unit 12 switches to the second operating mode, i.e., inhibited traction. However, the battery contactor of the tail unit 12 remains in the open state, as the auxiliary devices are powered by the electrical power that the contact shoes of the tail unit 12 can collect from the power rail.

[0077] In the third step 330, the two units remain in inhibited traction, as long as both units have not regained the ability to capture energy from the ground.

[0078] At the fourth stage 340, the head unit 11 regains the ability to collect energy from the ground. It then queries the tail unit 12 to determine if it can capture energy from the ground. If so, the head unit 11 switches to the first operating mode and its battery contactor is placed in the open state.

[0079] The head unit 11 informs the tail unit 12 of this change in operating mode. In response, the tail unit 12 also switches to the first operating mode. Its battery contactor, which was in the open state, remains in the open state.

[0080] In the fifth step 350, the tail unit 12 in turn enters the neutral zone 24 and loses power from the ground. At this moment, the tail unit 12 switches to the second operating mode and its battery contactor is placed in the closed state.

[0081] The tail unit 12 informs the head unit 11 of this change in operating mode, so that the head unit 11 in turn switches to the second operating mode. However, the battery contactor of the head unit 11 remains in the open state, the auxiliary devices being powered by the electrical power that the contact shoes of the head unit 11 can collect from the power rail.

[0082] In the sixth step 360, the two units remain in inhibited traction, as long as the two units have not regained the ability to capture energy from the ground.

[0083] In the seventh step 370, the tail unit 12 regains the ability to collect electrical power from the ground. It then queries the head unit 11 to determine if it is able to collect energy from the ground. If so, the tail unit 12 switches to the first operating mode. Simultaneously, its battery contactor switches to the open state.

[0084] This change in operating mode is communicated from the tail unit 12 to the head unit 11. Upon receiving this information, the head unit 11 switches to the first operating mode. Its battery contactor, which was in the open state, remains in the open state.

[0085] This third method of crossing a neutral zone allows for homogeneous vehicle operation, without using battery traction, but solely the inertia of the vehicle's units. This has the advantage of reducing the load on the onboard batteries, which only supply energy to auxiliary devices and only when it is not possible to power these auxiliary devices with energy captured from the ground system.

[0086] The process just described therefore consists of propagating the alternative operating mode selected by a unit which has lost the ability to collect current from the supply rail, to the other units of the vehicle.

[0087] Placing the units in a common alternative operating mode allows to have a homogeneous dynamic behavior between the different units at any time of crossing the neutral zone, in particular at the moment when, upon entering or leaving the neutral zone, a unit loses or regains ground power.

[0088] This results in increased comfort for passengers.

[0089] If in the previous description, the case of a power supply system by the While the ground has been specifically mentioned, those skilled in the art are familiar with other types of electrical power systems for which the present invention can be implemented. These include, for example, power supply systems using an overhead contact line, where the vehicle collects electrical power by means of pantographs.

[0090] Furthermore, the state of the battery contactors constitutes only an advantageous variant of the method according to the invention. Indeed, the choice can be made not to power the auxiliary devices when crossing a neutral zone, or at least to power only certain auxiliary devices considered essential.

Claims

Claims

1. A method for an electric vehicle (10) consisting of at least two units (11, 12) to cross a neutral zone (24) of an electrical power supply system, each unit comprising: a motor; at least one collection means (11, 13, 14, 16) capable of collecting external electrical power from the electrical power supply system; and a battery capable of delivering internal electrical power, each unit being capable of operating at the current time in an operating mode selected from a plurality of operating modes, the plurality of operating modes comprising: a main operating mode in which the motor operates using the external electrical power;and at least one alternative operating mode in which the motor is not powered by external electrical power, said method being characterized in that it comprises a step of crossing the neutral zone (24), in which, when at least one unit of the electric vehicle (10) detects that it is unable to collect external electrical power, said at least one unit switches to the alternative operating mode, and transmits information to each of the other units of the vehicle, said information being indicative of said switch to the alternative operating mode, and in that, upon receipt of said information, each of said other units switches to said alternative operating mode, so that at any time, each unit is in the same common operating mode so that the vehicle adopts a homogeneous dynamic.;

2. Method according to claim 1, in which, during the crossing step, when all the units of the electric vehicle are in the alternative operating mode and all the units of the electric vehicle detect that they are capable of collecting external electrical power, the units are able to communicate with each other to switch to the main operating mode.

3. Method according to claim 1 or 2, in which the crossing step is implemented for crossing a neutral zone when the speed of the electric vehicle (10) is greater than a first threshold speed, the first threshold speed being between 2 and 10 km / h, preferably equal to 5 km / h.

4. A method according to any one of claims 1 to 3, wherein said primary operating mode is a first operating mode and said at least one alternative operating mode comprises: a second operating mode, in which the motor is in inhibited traction, the unit moving on the ground; and a third operating mode, in which the motor operates in traction using internal electrical power supplied by the battery.

5. Method according to claim 4, wherein during the crossing step, the alternative operating mode corresponds to the third operating mode if the speed of the electric vehicle (10) is lower than a second threshold speed, and the alternative operating mode corresponds to the second operating mode if the speed of the electric vehicle (10) is greater than or equal to the second threshold speed, the second threshold speed being between 15 and 30 km / h, preferably equal to 20 km / h.

6. Method according to claim 4 or claim 5, wherein each unit (11, 12) comprises a first battery contactor suitable, in a closed state, for connecting the battery to auxiliary devices of the unit in question, and wherein when the common operating mode is the second operating mode: - the first battery contactor of a unit, which detects being able to collect the external electric power, is placed in an open state, the auxiliary devices being powered by the external electric power; and - the first battery contactor of a unit, which detects being unable to collect the external electric power, is placed in the closed state, the auxiliary devices being powered by the internal electric power.

7. Method according to any one of claims 4 to 6, in which each unit (11, 12) comprises a second battery contactor suitable, in a closed state, for connecting the battery to the engine and advantageously to auxiliary devices of the unit in question, and in which when the common operating mode is the third operating mode, the second battery contactor is in the closed state and when the common operating mode is the first operating mode the second battery contactor is in an open state.

8. Electric vehicle (10) consisting of at least two units (11, 12), each unit comprising: a motor; at least one collection means (13, 15, 14, 16) capable of collecting external electrical power from the electrical power supply system; and a battery capable of delivering internal electrical power, each unit being capable of operating at the current time in an operating mode selected from a plurality of operating modes, the plurality of operating modes comprising: a main operating mode in which the motor operates in traction using the external electrical power collected by the collection means;and an alternative operating mode in which the motor is not powered by external electrical power, characterized in that said electric vehicle is capable of implementing a crossing method according to any one of claims 1 to 7, a communication link being established between the units (11, 12) of the electric vehicle (10) in order to allow the transmission, between a first and a second unit, of information indicative of the operating mode at the current time of the first unit, so that the second unit adapts its operating mode at the current time accordingly, and vice versa.;

9. An electric vehicle (10) according to claim 1, wherein said vehicle is a guided vehicle, preferably a tram.

10. An electric vehicle (10) according to any one of claims 8 to 9, wherein the collecting means of a unit of said electric vehicle comprises a collector adapted to come into electrical contact with a power rail implanted in the ground of the electrical power system.

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