METHOD AND SYSTEM FOR AUTOMATIC ENERGY MANAGEMENT ON BOARD OF AN ELECTRIC VEHICLE

Abstract

This method of automatically managing the energy carried by an electric vehicle for a mission on an interstation between departure and arrival stations consists of: providing mission characteristics, which include a reference speed profile on segments subdividing the interstation; evaluating a current position and speed of the vehicle; estimating a cruising speed of the vehicle on the remaining segments, based on the reference speed profile, current speed and position; calculating a total predicted energy (emis-prev) as an estimate of the energy to be consumed to reach the arrival station, based on the current position, estimated cruising speeds and auxiliary power supplied to passenger comfort devices; determining an available on-board energy (eemb-dis) as energy stored by the vehicle at the current position;and display the total predicted energy and the available onboard energy.

Description

[0001] The present invention relates to a method and system for the automatic management of on-board energy in an electric vehicle, in particular a rolling transport system with on-board energy, such as a tram, a bus, or the equivalent.

[0002] Electric trams or buses are currently designed with on-board energy, stored in a suitable energy storage system (such as batteries, supercapacitors, etc.) so that they can operate, in total autonomy, over an interstation, that is to say between two charging stations.

[0003] The energy stored in the energy storage system is consumed either as traction energy (to bring the tram to a certain speed, maintain it at a cruising speed, or bring it to a certain altitude), or as comfort energy (i.e., the energy used by auxiliary devices on board the tram to ensure a certain level of comfort for passengers, for example lighting, heating, etc.).

[0004] Energy storage systems are currently sized to be able, in nominal mode, to transport, with normal thermal comfort, the maximum passenger load over the interstation of the line which is the most penalizing in terms of traction energy; and, in degraded mode (corresponding to a failure of a charging station), to be able to transport, with reduced thermal comfort, the maximum passenger load over two successive interstations without recharging the storage system at the intermediate charging station.

[0005] For example, a tram's energy storage system can store a maximum of 13.5 kWh of energy.

[0006] On-board electric rolling stock transport systems have many advantages (less ground infrastructure in rail, ability to recover braking energy, etc.), but present a specific risk of failure due to depletion of on-board energy before reaching a charging station, in other words a risk of "running out of power".

[0007] Currently, strategies for shedding comfort energy and / or traction energy are implemented to preserve the range of the electric vehicle when the remaining on-board energy in the energy storage system falls below a predefined critical threshold.

[0008] These strategies are predetermined. They therefore lack robustness, as they do not account for the inherent risks of operation, such as traffic slowdowns or even unexpected stops (at pedestrian crossings or intersections, for example). These predetermined strategies can thus fail under normal operating conditions.

[0009] Moreover, these strategies are defined on worst-case scenarios, which can lead to their implementation in the absence of a real need, when operating conditions (passenger load, weather conditions, etc.) are not the most adverse.

[0010] Furthermore, in the case of electric cars, we know of document WO 2010 / 043833 A1 which discloses a range estimation method allowing the prediction of the vehicle's energy consumption on a remaining route; document US2013 / 166123 A1, which estimates the maximum distance the car can still travel taking into account the on-board energy and the predicted energy, the latter being evaluated solely from current quantities (instantaneous vehicle speed and instantaneous power of the auxiliaries); document EP 2 849 312 A1, which discloses a system for optimizing the transfer of energy from a charging station to an electric vehicle in order to increase the lifespan of the vehicle's batteries;and document GB 2 483 454, which discloses the determination of the current position, the entry of a proposed destination and the calculation of a route connecting these points, the calculated route then allowing the evaluation of the vehicle's energy requirements.

[0011] The aim of the invention is therefore to solve this problem, by proposing in particular a system and a method to manage the energy consumption of the transport system, in particular by adjusting its speed, to anticipate and avoid the occurrence of such a critical situation, and to allow the system to reach the next charging station autonomously, both as quickly as possible and in the best conditions of comfort for the passengers.

[0012] For this purpose the invention relates to a method for automatic management of the energy on board a tramway and an automatic management system for the energy on board a tramway according to the attached claims.

[0013] The invention and its advantages will be better understood upon reading the following detailed description of a particular embodiment, given solely by way of non-limiting example, this description being made with reference to the accompanying drawings in which: Figure 1 is a schematic representation of the system according to the invention equipping a tramway; Figure 2 represents, in block form, the process according to the invention implemented by the system of Figure 1; Figure 3 represents a possible display in the cab of the relevant information delivered during the implementation of the process of Figure 2; and, Figure 4 represents, for the calculation of an optimum speed - auxiliary power, different reference curves in a total predicted energy versus set speed frame.

[0014] The automatic energy management process for an electric vehicle, designed to ensure mission completion, relies on calculating a total predicted energy, denoted Emis-prev, defined as an estimate of the energy required to finish the mission. This estimate is calculated from the vehicle's current position and is updated periodically as the vehicle travels.

[0015] While the mission of a vehicle is to transport passengers over an interstation, from a departure charging station to an arrival charging station, "finishing its mission" means the vehicle's ability to reach the arrival charging station, either in a nominal operating mode, consisting of reaching the arrival station within a set time and with a predefined level of passenger comfort, or in a degraded operating mode, consisting of reaching the arrival station in a longer time and / or with reduced passenger comfort.

[0016] The total predicted energy Emis-prev is then periodically compared to the available onboard energy Eemb-dis, which corresponds to the onboard energy Eemb minus the reserve energy Eres. The onboard energy Eemb is the energy stored in the electric vehicle's energy storage system, advantageously reassessed periodically based on the vehicle's progress and the time elapsed since departure. The reserve energy Eres corresponds to the energy required to reach the next inter-station in the event of a malfunction in the charging system at the arrival station.

[0017] Comparing these two energy values, Emis-prev and Eemb-dis, allows for the periodic assessment of the electric vehicle's range, that is, its ability to complete its mission. This enables the electric vehicle's energy consumption to be managed appropriately, particularly by adjusting the vehicle's speed and / or the auxiliary power supply to auxiliary devices.

[0018] In particular, when the total predicted energy Emis-prev exceeds the available on-board energy Eemb-dis, the process advantageously provides for the automatic determination of an optimal operating point in terms of speed and auxiliary power. This optimal operating point is proposed to the driver or automatically applied as a setpoint to the speed control system and / or the auxiliary power control system.

[0019] In what follows, as shown in Figure 1, the invention will be described more particularly for an electric vehicle of the tram type 2, equipped with an energy storage system, for example batteries 4. Alternatively, other types of storage systems are conceivable, in particular supercapacitors.

[0020] The batteries 4 provide electrical power to a traction motor 6, as well as a converter 8 for powering auxiliary devices.

[0021] Tram 2 is equipped with a system 10 designed to implement the automatic on-board energy management process according to the invention.

[0022] The system 10 includes a calculator 12, which is a computer designed to execute the instructions of a computer program.

[0023] Based on raw input data received via its input / output interface from various peripherals, the computer 12 is capable of calculating different input data for the process according to the invention. This input data includes, for example and preferably: the onboard energy Eemb, which corresponds to the energy stored by the batteries 4 at the current time; the position X of the tram along the interstation considered; the speed V of the tram; the mass M of the tram; the auxiliary power Paux supplying the auxiliary devices at the current time; the location of the current interstation.

[0024] More specifically, the on-board energy Eemb is for example measured using a suitable sensor 24 associated with batteries 4.

[0025] Position X is the instantaneous position of tram 2 between the two departure and arrival stations defining the ends of the inter-station area. It corresponds to the distance traveled from the departure station. Position X is determined, for example, using odometric devices 22 equipping tram 2, in particular a phonic wheel that measures the distance traveled from the departure station, taken as the origin.

[0026] The current speed V is the average over a few seconds, for example three seconds, of the instantaneous speed provided for example by odometric means 22, in particular a tachometer suitable for measuring the instantaneous speed of the tram 2.

[0027] The mass M, for example, is the value provided by tram 2's braking subsystem 23 when the tram leaves the departure station. This subsystem determines the mass based on signals from appropriate load sensors. Therefore, the mass M takes into account the number of passengers on board tram 2.

[0028] The auxiliary power Paux is, for example, determined by the maximum value, over a window of a few minutes, for example six minutes (the characteristic cycling time of auxiliary air conditioning devices), of the average over a few seconds, for example ten seconds, of the instantaneous auxiliary power consumed at the given moment by all the auxiliary devices on board the tram, in particular the air conditioning and heating systems in the tram cars for passenger comfort. The instantaneous auxiliary power is, for example, measured by a suitable power sensor 28 fitted to the converter 8.

[0029] The location of the current interstation is obtained by querying a ground control system via the computer 12 at the time of the station stop. This is done, for example, via a wireless link established by a radio communication module 29 fitted to tram 2.

[0030] The location thus obtained allows computer 12 to query an on-board database of the tram, to determine the characteristics of the mission on the current interstation.

[0031] Specifically, this involves the distance D separating the end stations of the interstation, reference velocities Vref-i on each segment (indexed by the integer i) of the various segments subdividing the interstation, and an elevation profile. The elevation profile is, for example, a discretized diagram of the elevation Z as a function of the position X, preferably including only the points at the beginning and end of slope changes.

[0032] These features also include the Eres reserve energy to be provided in order, in the event of a malfunction of the charging system at the arrival station, to allow the tram to reach the next charging station.

[0033] The system outputs a plurality of output data, such as, for example and preferably: a total predicted energy Emis-prev(X) while the tram is at position X, corresponding to an estimate of the energy that is expected to be consumed to finish the mission from position X; an available on-board energy Eemb-dis(X), resulting from the difference between the on-board energy Eemb(X) and the reserve energy Eres; a real-time diagnosis on the ability to finish the mission, based on the comparison between the total predicted energy Emis-prev(X) and the available on-board energy Eemb-dis(X); an auxiliary power setpoint Paux*; a speed setpoint V*.

[0034] All or part of the output data is displayed on a screen 30 located in the cab to inform the tram driver 3 and help him to take appropriate actions. Preferably, all or part of the output data is transmitted to a control module 36 of the traction motor 6 and / or to a control module 38 of the converter 8.

[0035] The 100 method for automatic management of on-board energy will now be described with reference to Figure 2.

[0036] At stage 110, while tram 2 is stopped at the departure station, it collects the mission characteristics for the interstation. The interstation characteristics are communicated to the computer 12 via the ground-to-onboard link and the radio communication module 29.

[0037] Then, as tram 2 moves across the interstation between the departure and arrival stations, the following steps are periodically iterated.

[0038] At step 120, the calculator 12 determines the position X relative to the starting station and measures the time t elapsed since the departure from the starting station.

[0039] At stage 130, computer 12 estimates an auxiliary power Paux, a cruising speed Vcrois-i for each segment i on the end of the interstation, and a time T to complete the mission and reach the arrival station.

[0040] For example, in step 132, the calculator 12 determines the auxiliary power Paux from the measurement delivered by the sensor 28, as shown above.

[0041] At step 134, the calculator 12 determines the speed V from the measurement delivered by the system 22, as indicated above.

[0042] At step 135, it compares the speed V determined at the current moment to the reference speed Vref for the section of the intersection on which the tram is engaged.

[0043] It interprets a small difference between the speed V and the reference speed Vref-i on the current segment i as a minor disturbance and anticipates an imminent return of the speed V to the reference speed Vref-i. The cruising speed Vcrois-i is therefore taken to be equal to the speed Vref-i, not only on the current segment i but also on subsequent segments, i+1, i+2, etc.

[0044] It interprets a significant difference between the speed V and the reference speed Vref as a sign of traffic disruption caused by an unforeseen event and anticipates the tram continuing at this reduced speed V for the remainder of the section. The cruising speed Vc is therefore assumed to be equal to the speed V.

[0045] Finally, if the speed V is zero, it is advantageous to use, during the restart of the tram after stopping, a cruising speed equal to the cruising speed before stopping.

[0046] More specifically, the computer 12 can advantageously manage an unexpected stop (for example, at a pedestrian crossing or intersection). To do this, the computer 12 memorizes the cruising speed before the stop and anticipates a restart at this cruising speed. Thus, when the tram restarts, the memorized cruising speed is used for a predetermined duration for the implementation of the process, which can be a function of the acceleration time required to reach this cruising speed. Once the restart is complete, the system 10 again uses the measured speed V to predict a new cruising speed. In this way, during the acceleration phase, it is possible to obtain a reasonable estimate of the kinetic energy required to complete the journey, the cruising speed used being, a priori, the reference speed and not the tram's low speed when it leaves the stop.

[0047] At step 136, the calculator 12 relies on the results of step 135 to predict the cruising speeds Vcrois-i on the following sections of the interstation, up to the arrival station.

[0048] If at step 135 a small difference was observed, the calculator 12 considers that, on the following sections i, the tram's setpoint speed Vci will be the reference speed Vrefi associated with each of these sections.

[0049] If, on the other hand, at step 135, a significant discrepancy has been observed, the calculator 12 considers that, on the following sections i, the initially planned cruising speed Vcrois-i will be reduced compared to the reference speed Vref-i associated with each of these following sections.

[0050] At step 138, computer 12 uses the cruising speeds Vci on the current and subsequent sections, as well as the lengths of these sections, to predict the duration T of the mission.

[0051] Then, at step 140, computer 12 estimates the total predicted energy Emis-prev(X0), which is the energy that must be predicted to be consumed to complete the mission, when the tram is at position X0.

[0052] The total predicted energy Emis-prev is calculated as the sum of a traction energy Etrac and an auxiliary energy Eaux.

[0053] Traction energy includes a kinetic energy component Ekin (corresponding to the traction energy to be supplied to bring the vehicle to a certain speed), a potential component Epot (corresponding to the energy to be supplied to bring the vehicle to a certain altitude) and a friction component Efrot (corresponding to the energy to be supplied to overcome the resistance to forward motion).

[0054] Auxiliary power refers to the power to be supplied to auxiliary passenger comfort devices.

[0055] For these estimates, calculator 12 uses the results of step 130 (Paux, Vcrois-1, Vcrois-2, Vcrois-3,... and T) and step 120 (X, t) as well as the characteristics of the interstation (length of the interstation, altitude profile).

[0056] For example, the predicted kinetic energy is calculated using the vehicle's mass and the projected cruising speeds (Vcrois-i) for completing the mission. Furthermore, this calculation incorporates speed differences between the various segments and the traction phases during acceleration, or braking phases during deceleration (advantageously with regenerative braking). This calculation of predicted kinetic energy distinguishes the contributions of these phases by using a negative or positive sign, and considers traction efficiency and braking efficiency in the case of electric braking. Advantageously, the absence of regenerative braking below a threshold speed, such as 13 km / h, is taken into account; below this threshold, braking is mechanical by necessity and no longer electric.

[0057] For example, the expected duration T for the end of the mission multiplied by the auxiliary power Paux gives the expected auxiliary energy to be supplied to finish the mission.

[0058] For example, friction energy is accounted for as a fixed amount per station and allocated proportionally based on progress. This simplification is compatible with the precision required for tramways. The friction component can be calculated using a more specific model of resistance to forward motion for any onboard energy transport system.

[0059] The total predicted energy (Emis-prev) calculated at point X0 is the energy required to complete the mission. It is updated periodically to reflect the vehicle's progress. With each update, it is directly compared to the available onboard energy (Eemb-dis), which is also updated periodically to reflect the energy actually consumed to reach the current point. This calculation and comparison mechanism naturally adjusts the total energy required for the mission to be the sum of the energy already consumed and the energy remaining to be supplied to complete the mission.

[0060] Alternatively, step 140 is inhibited during the first five to ten seconds after a start-up, allowing the tram time to accelerate to a stabilized speed that can be considered cruising speed. This helps limit the risk of overestimating the total predicted energy Emis-prev(X).

[0061] Advantageously, the calculator 12 incorporates appropriate energy efficiencies into each of the energy estimates. For example, to provide a useful kinetic energy of 1 kWh, the motor 6 will need to consume 1.08 kWh of energy, taking into account a traction efficiency of 0.82, which corresponds to an onboard energy of 1.13 kWh, in the case of an electrical efficiency of 0.95 for the batteries 4.

[0062] If electrical losses are taken into account in this way, mechanical losses are taken into account through friction energy which encompasses all forms of mechanical and aerodynamic resistance to the advancement of the tram.

[0063] Fixed yields are considered for each type of energy transformation, which is consistent with the necessary accuracy of energy forecasting required to establish a prediction for the end of the mission.

[0064] Process 100 includes a step 144 of determining the available on-board energy Eemb-dis (X). This energy is the difference between the on-board energy Eemb(X) and the reserve energy Eres.

[0065] The on-board energy Eemb(X) is preferably updated periodically. It is derived from the measurement delivered by sensor 24 at the current time. Alternatively, it can be calculated based on the progress along the interstation.

[0066] Since the tram's autonomy is generally defined as two consecutive stops, a reserve energy (Eres) is set aside to allow for a restart at the arrival station and, in exceptional circumstances, the continuation of the tram's journey without recharging at the arrival station, up to the next charging station. Thus, tram 2 will be able to complete two stops without recharging in the event of a complete failure of the charging system at the arrival station. This means that the tram must reach the arrival station without having consumed this reserve energy.

[0067] At step 146, the information just calculated is displayed in the cabin on screen 30. For example, as illustrated in figure 3, the screen displays a gauge 200 indicating, by a first moving symbol 210, the total predicted energy Emis-prev(X) and, by a second symbol 220, the available on-board energy Eemb-dis(X), relative to the level 230 of the reserve energy Eres.

[0068] At step 150, the calculator 12 establishes an energy diagnosis by comparing the total predicted energy Emis-prev(X) and the available on-board energy Eemb-dis(X).

[0069] If the available onboard energy Eemb-dis(X) is greater than the energy required at the end of the mission Emis-prev(X), this means that the 4 batteries store enough energy to complete the mission, with the current regime in terms of cruising speed and auxiliary power.

[0070] Steps 120 to 146 are iterated (loop 101) leading to the update of the values ​​of Emis-prev(X) and Eemb-dis(X).

[0071] If the total available on-board energy Emis-prev(X) is less than or equal to the energy required to complete the total planned mission Emis-prev(X), this means that the energy stored by the batteries 4 is insufficient to complete the mission with the current regime.

[0072] Thus, in the case of an indicative diagnosis of a lack of autonomy, process 100 continues with a step 160 of identifying a speed-auxiliary power pair to complete the mission.

[0073] During step 160, the calculator 12 implements an optimization algorithm to identify, in real time, an optimum speed - auxiliary power.

[0074] This optimum is a compromise. A higher cruising speed requires more traction energy to reach that speed, but saves comfort energy by shortening the time spent at the end of the interstation and consequently the time required to use auxiliary equipment. Conversely, a lower cruising speed requires less traction energy, but increases the time to reach the arrival station and therefore more comfort energy, unless auxiliary power is reduced.

[0075] In the currently envisaged embodiment, the following constraints are successively implemented: The first constraint is to ensure that the tramway fulfills its mission of transporting passengers by reaching the arrival station. Therefore, the total projected energy must be less than the available energy.

[0076] The second constraint is to ensure that the mission is completed within the allotted time, for example, according to a tramway timetable. Therefore, a reduction in cruising speed will only be recommended when absolutely necessary. In other words, the plan is to begin by reducing auxiliary power and to reduce traction power only if reducing auxiliary power does not allow the mission to be completed.

[0077] The third constraint is to reduce auxiliary power consumption in a way that limits the impact on the thermal and visual comfort experienced by passengers. Therefore, reducing the power of auxiliary systems is only recommended when absolutely necessary to conserve onboard energy and regain autonomy at the arrival station.

[0078] The optimum operating point that allows reaching the arrival station as quickly and comfortably as possible is selected.

[0079] In one possible embodiment, several reference curves are first calculated, such as those shown in Figure 4. Each curve gives the total predicted energy Emis-prev(X) as a function of the setpoint speed Vc for a given value of the auxiliary power Paux. These curves are obtained by calculations similar to those presented above for estimating the total predicted energy.

[0080] Then, iteratively, a total predicted energy is calculated with an auxiliary power level lower than the current level. To do this, the calculator has a load shedding table indicating the different discrete levels of auxiliary power, between a nominal power and a minimum power.

[0081] If this reduction in auxiliary power allows for a new positive energy diagnosis, then the calculator 12 exits step 160.

[0082] If, on the contrary, this is not the case, the next iteration of the calculation of the total predicted energy is done with a reduced cruising speed of an increment of 5 km / h, for example.

[0083] If this reduction in cruising speed allows for a new positive energy diagnosis, the computer exits step 160.

[0084] If, on the other hand, this is not the case, the calculation is iterated.

[0085] Depending on the weight of the constraints described above, we can link two or three steps of the calculation by decreasing the level of auxiliary power before engaging a step of reducing the cruising speed.

[0086] Thus, in Figure 4, to reach the next station, the optimum must result in a total planned energy lower than the available energy (first constraint). If the available energy (Eemb-disp) is 10 MJ, this energy is insufficient to reach the next station with the maximum auxiliary power of 112 kW, regardless of speed; it is sufficient with an auxiliary power reduced to 65 kW for a speed range between 35 and 13 km / h, or with an auxiliary power reduced to 30 kW for a speed range between 43 and 10 km / h. If the arrival time at the destination station requires an optimal cruising speed of 37 km / h (second constraint), then the auxiliary power must be set at 30 kW (third constraint).

[0087] An optimum C(Vc*, Paux*) is thus determined at the output of step 160.

[0088] This optimum corresponds to speed setpoints Vc* and auxiliary power Paux*.

[0089] At step 170, these instructions are displayed as recommendations on screen 30 to inform driver 3. The driver carries out the recommended actions if he wishes, in particular taking into account other operating parameters of his vehicle.

[0090] Alternatively, these instructions are transmitted to adapted tramway systems for automatic processing.

[0091] Thus, a control module 36 can filter the driver's acceleration commands and limit their speed to the set speed or recommend that they accelerate if their speed is too low. Alternatively, the control module 36 directly regulates the motor based on the speed setpoint Vc* to modify the tram's instantaneous speed. A control module for managing auxiliary devices will regulate the instantaneous power supply to these devices based on the auxiliary power setpoint Paux*, notably by sending power limitation commands to the various auxiliary devices, which can include a stop command.

[0092] These instructions are updated in real time according to the train's progress. For this purpose, steps 120 to 170 of the process are iterated (loop 102).

[0093] At stage 180, the computer 12 advantageously detects arrival at the station thanks to the monitoring of its progress along the interstation and the detection of a zero speed.

[0094] The calculator 12 verifies that the planned recharging at the arrival station is effective, thanks for example to the evolution of the measurement of the energy stored by the batteries 4.

[0095] If so, the calculator 12 stops the load shedding of auxiliary devices if such load shedding was initiated, and resets the speed instructions.

[0096] Steps 110 to 180 are executed again (loop 103) on the next interstation.

[0097] On the contrary, if computer 12 detects a stop at a station and an absence of effective charging, it updates the total provisional energy according to the need on the new interstation and it evolves the calculation of the available on-board energy by including the reserve energy, which is planned to be used for this scenario.

[0098] In one embodiment, instead of measuring the onboard energy, it is proposed to calculate it using the same calculation principles as those for the total predicted energy. This embodiment can advantageously compensate for inaccuracies in the measurement of the onboard energy by the energy storage system.

[0099] In a second embodiment, the calculation of the optimum speed-auxiliary power can be done with a specific prioritization, according to the operator's preferences, for example with comfort first and travel time second.

[0100] In a variant where the tram is equipped to recover energy during braking, this recovered energy can be stored in the batteries, and the recovered energy is taken into account in determining the available on-board energy.

[0101] This recovered energy can be used directly to power auxiliary devices. The recovered energy is then taken into account in the estimation of the total predicted energy Emis-prev(X).

[0102] These calculations will be made taking into account the recovery efficiency of this braking energy, as well as the efficiency of the traction part and the efficiency of the storage part and taking into account the absence of recovery below a threshold speed which is for example 13 km / h.

Claims

1. A method (100) for managing automatically the energy stored by a tramway (2) for a transport mission over an interstation between a departure recharge station and an arrival recharge station, including the following steps: - providing (110) predetermined characteristics relative to the mission, the predetermined characteristics comprising a reference speed profile; - evaluating (132, 134) a current position and speed of the tramway; - estimating (135, 136) a cruising speed of the tramway over the segments remaining to be traveled, based on the reference speed profile, the current speed and the current position; - calculating (140) a total anticipated energy (Emis-prev) as an estimate of the energy to be consumed to reach the arrival recharge station, based on the current position, the estimated cruising speed and an auxiliary power (Paux) supplied to auxiliary passenger comfort devices of the tramway; - determining (144) an available stored energy (Eemb-dis) as energy stored by an energy storage system (4) of the tramway in the current position; - displaying (150), on a screen (30), the total anticipated energy and the available stored energy, - comparing (160) the available stored energy (Eemb-dis) and the total anticipated energy (Emis-prev), and, - when the total anticipated energy is greater than the available stored energy, identifying (170) a speed - auxiliary power optimum making it possible to reach the arrival station, the speed - auxiliary power optimum being identified so as first to make it possible to reach the arrival station, then to reach the arrival station at a predetermined arrival time, and lastly to reach the arrival station with a predetermined comfort level.

2. The method according to claim 1, wherein the speed-auxiliary power optimum is applied as input to a system for regulating the speed and / or a system for regulating the auxiliary power.

3. The method according to any one of claims 1 to 2, wherein the interstation is made up of a plurality of segments and the calculation of the total anticipated energy (Emis-prev) is done by providing a cruising speed on each segment (i) of the interstation remaining to be traveled and by providing a current auxiliary power (Paux) supplied to the auxiliary passenger comfort devices as auxiliary power on the segments of the interstation remaining to be traveled and by providing a travel time for the segments of the interstation remaining to be traveled.

4. The method according to any one of claims 1 to 3, wherein the calculation of the total anticipated energy (Emis-prev) is further done by using an altitude profile over the segments of the interstation remaining to be traveled.

5. The method according to claim 3, wherein the forecast of the auxiliary power is done by using the travel time and an averaged measurement of the auxiliary power.

6. The method according to claim 3 or 4, wherein the calculation of the total anticipated energy (Emis-prev) is further done by using the anticipated cruising speeds and speed deviations, by differentiating between accelerations and decelerations of the electric vehicle.

7. The method according to any one of claims 1 to 6, wherein the calculation of the stored available energy (Eemb-disp) is done from an energy stored by the storage system at the current moment, from which a reserve energy is subtracted, defined as the energy needed to cross the following intersection.

8. A system (10) for automatically managing energy stored by an electric vehicle (2), the system being stored on board the electric vehicle, characterized in that it is capable of carrying out the method according to any one of claims 1 to 7.