METHOD FOR DETERMINING A CAPACITANCE VALUE OF AT LEAST ONE SUPERCAPACITOR IN AN ELECTROMECHANICAL BRAKE SYSTEM OF AT LEAST ONE VEHICLE, ELECTROMECHANICAL BRAKE SYSTEM, AND VEHICLE - Patent application

Abstract

A method is described for determining a capacitance value of a first supercapacitor (100) of an electromechanical braking system (102), the electromechanical braking system (102) also comprising a second supercapacitor (101). The method comprises the following steps a)-f): a) measuring a first voltage value at the terminals of the second supercapacitor (101); b) if the first voltage value is greater than a predefined minimum voltage value, performing a charging or discharging operation of the first supercapacitor to bring the terminals of the first supercapacitor to a second voltage value equal to or greater than the minimum voltage value; c) determining a first voltage fluctuation at the terminals of the first supercapacitor (100); d) determining a first voltage fluctuation rate; e) measuring a first current value flowing through one of the terminals of the first supercapacitor (100); f) calculating the capacitance value of the first supercapacitor (100) by the ratio between the measured first current value and the first voltage fluctuation rate. An electromechanical braking system and vehicle using the method are also described.

Description

[Technical field]

[0001] The present invention generally belongs to the field of methods and braking systems for vehicles, in particular the present invention relates to a method for determining a capacitance value of at least one super capacitor of an electro-mechanical braking system of at least one vehicle, an electro-mechanical braking system and a vehicle equipped with this electro-mechanical braking system. [Background technology]

[0002] Today, new electromechanical brake systems based on mechatronic technology are being developed, e.g. for railway applications, whose design must functionally reproduce what was previously offered by a conventional electro-pneumatic brake, in particular with regard to safety-related functions.

[0003] These new electromechanical braking systems therefore need to ensure that: - an amount of energy is stored that is able to ensure at least one emergency braking action; - Emergency braking of the entire vehicle reaches a predetermined minimum safe level.

[0004] For example, braking systems typically include energy storage means configured to store sufficient energy to enable the electro-pneumatic braking system to perform at least one complete emergency braking operation.

[0005] Depending on the type of braking system, the energy storage means can take a variety of forms.

[0006] In the case of a pneumatic braking system, this energy storage means may conventionally be, for example, an auxiliary tank. In this case, the energy is stored by storing compressed air in the auxiliary tank, the volume of which is constant and invariable. In order to meet the necessary safety requirements, the internal pressure in the auxiliary tank is usually continuously measured by one or more pressure sensors (to meet any redundancy requirements).

[0007] By monitoring the pressure in the auxiliary tank, it is possible to immediately identify the loss of stored energy needed to perform emergency braking and, optionally, to intervene quickly to restore safety.

[0008] In an electromechanical braking system, however, the energy storage means may also be mechanical means for storing mechanical potential energy, which may for example be a helical spring. The mechanical means for storing mechanical potential energy stores the energy required to apply at least one emergency braking action and may obviously perform the same functions as those performed by the auxiliary tank described above.

[0009] Again, in order to meet the required safety requirements, the mechanical energy stored in the mechanical means for storing mechanical potential energy can be monitored by suitable sensors.

[0010] Again, by monitoring the energy stored in the mechanical means for storing mechanical potential energy, any loss of the stored energy required to perform emergency braking can be immediately identified and, optionally, rapid intervention can be performed to restore safety.

[0011] Obviously other forms of mechanical energy storage could also be used, such as, as a non-exclusive example, a flat helical spring, if the force transmission is rotational rather than translational.

[0012] In a further example, the stored energy may be kinetic energy, stored in a flywheel that is kept in proper rotation by an electric motor. Again, the stored kinetic energy can be monitored by suitable sensors to meet safety requirements. By monitoring the kinetic energy stored in a mechanical means for storing kinetic energy, any loss of stored kinetic energy required to perform emergency braking can be immediately identified and, optionally, rapid intervention can be performed to restore safety.

[0013] In yet another embodiment, the energy storage means of the electromechanical braking system may be an electrical energy storage device, for example a supercapacitor. In this case, an energy charger is able to transfer energy from a source to the supercapacitor. According to what has been said above, the supercapacitor performs the same function as that performed by the auxiliary tank, the supercapacitor storing (stores) the electrical energy required to apply at least one emergency braking action.

[0014] The energy stored in a supercapacitor is: Energy = 1 / 2 x C x V 2 and where C is the capacitance and V is the potential.

[0015] It is therefore necessary to monitor the voltage across the capacitor and its capacitance in order to be able to monitor the actual presence of sufficient energy for braking.

[0016] However, in terms of capacity, a supercapacitor typically has a nominal capacitance value that indicates the amount of electrical energy that can be stored within it. Unfortunately, a supercapacitor undergoes wear, which gradually reduces its capacity over the course of its use. This wear can even reach a level where the supercapacitor can no longer store a sufficient amount of electrical energy to perform a full emergency brake.

[0017] To measure the capacity of a supercapacitor, the prior art discloses systems and methods that require altering the availability of energy stored in the supercapacitor, temporarily impairing the ability to perform emergency safety braking. Summary of the Invention [Problem to be solved by the invention]

[0018] The object of the present invention is therefore to provide a solution which makes it possible to monitor the remaining capacity of a supercapacitor of an electromechanical braking system of at least one vehicle without temporarily impairing the ability to perform emergency safety braking, thus further increasing the safety level of the electromechanical braking system.

[0019] These and other objects and advantages are achieved according to one aspect of the invention by a method for determining a capacitance value of at least one supercapacitor of an electromechanical braking system of at least one vehicle, the method having the features defined in claim 1.

[0020] According to a further aspect of the present invention, the above and other objects and advantages are achieved by an electromechanical braking system for at least one vehicle, said system having the features defined in claim 13.

[0021] These and other objects and advantages are achieved according to a further aspect of the invention by a vehicle having the features defined in claim 20.

[0022] Preferred embodiments of the invention are defined in the dependent claims, the content of which is to be understood as an integral part of this description. [Brief description of the drawings]

[0023] The functional and structural features of some preferred embodiments of a method for determining the capacitance value of a supercapacitor of at least one vehicle electromechanical braking system, an electromechanical braking system, and a vehicle according to the invention will now be described with reference to the accompanying drawings.

[0024] [Figure 1] FIG. 1 is a first flow chart illustrating an embodiment of a method for determining a remaining capacity value of at least a first emergency supercapacitor of an electromechanical braking system of at least one rail vehicle according to the present invention. [Diagram 2] FIG. 2 illustrates a first embodiment of an electromechanical braking system comprising a first supercapacitor and a second supercapacitor. [Diagram 3] FIG. 3 illustrates a second embodiment of an electromechanical braking system comprising a first supercapacitor and a second supercapacitor. [Figure 4] FIG. 4 illustrates a second embodiment of an electromechanical braking system comprising a first supercapacitor and a second supercapacitor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Before describing the embodiments of the present invention in detail, it should be made clear that the present invention is not limited in its application to the design details and configuration of components set forth in the following description or illustrated in the drawings. The present invention can envision other embodiments and can actually be implemented or constructed in different ways. It is also to be understood that the phraseology and terminology are for descriptive purposes and should not be construed as limiting. The use of "include" and "comprise" and variations thereof are intended to encompass the elements described below and their equivalents, as well as additional elements and their equivalents.

[0026] By way of example, and with reference to Fig. 1, the following describes a first embodiment of a method for determining a capacitance value of at least a first supercapacitor 100 of at least one vehicle electromechanical braking system 102. The electromechanical braking system 102 further comprises a second supercapacitor 101. In particular, the first supercapacitor 100 is configured to store a first amount of electrical energy sufficient to cause the electromechanical braking system 102 to perform at least one emergency braking operation, and the second supercapacitor 101 is configured to store a second amount of electrical energy sufficient to cause the electromechanical braking system 102 to perform at least one emergency braking operation.

[0027] In a first embodiment, the method comprises the following steps a)-f): a) measuring a first voltage value at a terminal of the second supercapacitor 101; b) performing a charging or discharging operation of the first supercapacitor 100 during a first measurement time period if the first voltage value is greater than a predetermined minimum voltage value, the charging or discharging operation being configured such that the terminals of the first supercapacitor 100 assume a second voltage value; c) determining a first voltage variation at the terminals of the first supercapacitor during the first measurement time interval; d) determining a first voltage variation rate based on the first voltage variation at the terminals of the first supercapacitor 100 determined in step c) and a duration of the first measurement time interval; e) measuring a first current value through one of the terminals of the first supercapacitor 100 at a first measurement instant of the first measurement time interval; f) calculating the capacitance value of the first supercapacitor 100 according to the ratio between the first current value measured at the first measurement time and the first voltage fluctuation rate;

[0028] In other words, the voltage across the second supercapacitor 101 can be monitored to verify that it is greater than a predefined minimum voltage value. This minimum voltage value may be determined as a value indicative of the fact that the energy stored in the second supercapacitor 101 is sufficient to perform an emergency braking operation if necessary. Once it is verified that the second supercapacitor 101 is sufficiently charged to be able to perform an emergency braking operation, it is possible to charge or discharge the first supercapacitor 100 during a measurement time interval. This charging or discharging operation is configured such that the terminals of said supercapacitor can assume a second voltage value. This second voltage value may be either greater than or less than the minimum voltage value at the terminals of the second supercapacitor 101, if necessary, with a second supercapacitor sufficiently charged as a backup to perform an emergency braking operation. During said measurement time interval during which the charging or discharging operation is performed, the voltage variation at the terminals of the first supercapacitor 100 can be determined, for example by measurement. For example, if initially the voltage across a first supercapacitor is 50 V and at the end of a discharge operation the voltage across the supercapacitor is 40 V, the voltage variation at the terminals of the first supercapacitor is 10 V. However, if initially the voltage across the first supercapacitor is 50 V and at the end of a charge operation the voltage across the first supercapacitor is 55 V, the voltage variation at the terminals of the supercapacitor is 5 V.

[0029] Once the voltage variation at the terminals of the first supercapacitor 100 has been determined, a voltage variation rate, also known as a voltage variation speed, can be determined based on the voltage variation at the terminals of the first supercapacitor and the duration of the measurement time interval. A current value flowing at one terminal of the first supercapacitor at a measurement instant of the measurement time interval can also be measured. The measured current value flowing at one terminal of the first supercapacitor can be an absorption current entering the terminals of the supercapacitor during a charging operation experienced by the supercapacitor, or a current exiting the terminals of the supercapacitor during a discharging operation experienced by the supercapacitor.

[0030] For example, the measurement instant may be the instant immediately following the start of the measurement time interval, or the instant immediately preceding the end of the measurement time interval, or an instant between the instant immediately following the start of the measurement time interval and the instant immediately preceding the end of the measurement time interval. A current value flowing through one of the terminals of the supercapacitor may be measured at multiple measurement instants during the measurement time interval.

[0031] Finally, the capacitance value of the first supercapacitor can be calculated by the ratio between the first current value measured at the measurement time and the first voltage fluctuation rate. For example, the following formula can be applied: i = c*dv / dt -> c = i / (dv / dt) where i is the value of a first current flowing into one of the terminals of the first supercapacitor at a measurement time in the measurement time interval, c is the capacitance of the first supercapacitor, and dv / dt is the rate of voltage change (i.e., the derivative over time of the voltage across the first supercapacitor). This can be applied to the second supercapacitor as well.

[0032] For example, with respect to the field of rail vehicles, emergency braking is a braking action in which at least one rail vehicle stops or slows down to walking pace. Emergency braking may be activated automatically, for example, when a potentially dangerous situation is detected by at least one system of the rail vehicle. The prior art is analyzed with particular reference to the field of rail vehicles.

[0033] Within the railway sector the following European standards can be referenced: -EN50126 [Railway applications. Specification and demonstration of Reliability, Availability, Maintainability and Safety (RAMS)] -EN50128 ["Railway applications. Communication, signalling and processing systems. Software for railway control and protection systems"] -EN50129 ["Railway applications. Communication, signalling and processing systems. Safety-related electronic systems for signalling"]. -EN50159 ["Railway applications. Communication, signalling and processing systems. Safety-related communications in transmission systems"].

[0034] In particular, standard EN50126 defines a methodology for assigning safety levels SIL0 / 1 / 2 / 3 / 4 (with safety level SIL4 indicating the maximum safety level) to subsystems constituting a system based on the results of a safety analysis, and standards EN50128 and EN50129 define design criteria to be applied to software and hardware components, respectively, based on the SIL levels assigned based on the results of the safety analysis. Systems involved in braking are usually required to have a safety level SIL=4.

[0035] Referring instead to the road vehicle sector, the emergency brake may apply brakes in accordance with the required NCAPs related to emergency braking, which makes it possible to stop or slow down the road vehicle in order to protect pedestrians or to prevent an imminent accident with the vehicle.

[0036] Step a), i.e. measuring the first voltage value at the terminals of the second supercapacitor 101, is preferably performed when the second supercapacitor 101 is not undergoing a charging action, so that the measurement is not influenced by the charging voltage applied to the terminals of the second supercapacitor for charging it.

[0037] Step d), i.e. determining a first voltage variation rate based on the first voltage variation at the terminals of the first supercapacitor determined in step c) and on the duration of the first measurement time interval, preferably comprises: - determining a first voltage variation rate by the ratio between the first voltage variation determined in step c) and the duration of the first measurement time interval.

[0038] For example, if the voltage fluctuation at the terminals of the first supercapacitor is 10 V and the measurement time interval lasts for 2 s, the first voltage fluctuation rate is 5 V / s.

[0039] The method for determining the capacitance value of at least a first supercapacitor preferably comprises the following steps a')-f'): a') measuring a third voltage value at a terminal of the first supercapacitor 100; b') performing a charging or discharging operation of the second supercapacitor 101 during a second measurement time interval if the third voltage value is greater than the predetermined minimum voltage value, the charging or discharging operation being configured such that the terminals of the second supercapacitor 101 assume a fourth voltage value; c') determining a second voltage variation at the terminals of the second supercapacitor 101 during the second measurement time interval; d') determining a second voltage fluctuation rate based on the second voltage fluctuation at the terminals of the second supercapacitor 101 determined in step c) and the duration of the second measurement time interval; e') measuring a second current value through one of the terminals of the second supercapacitor 101 at a second measurement time point during the second measurement time interval; f') calculating the capacitance value of the second supercapacitor 101 according to the ratio between the second current value measured at the second measurement time point and the second voltage fluctuation rate.

[0040] In other words, not only can the capacitance value of the first supercapacitor be measured, but the capacitance value of the second supercapacitor can also be measured.

[0041] Said step a') is preferably carried out when the first supercapacitor is not undergoing a charging action, so that the measurement can be performed without being influenced by the charging voltage applied to its terminals in order to charge the first supercapacitor.

[0042] Said step d') preferably comprises: - determining a second voltage variation rate by the ratio between the second voltage variation determined in step c) and the duration of the second measurement time interval. For example, if the voltage fluctuation at the terminals of the second supercapacitor is 10 V and the measurement time interval lasts for 2 s, then the second voltage fluctuation rate is 5 V / s.

[0043] The first measurement time interval and the second measurement time interval are preferably equal, in other words, the measurement time applied to measure the capacitance value of the first supercapacitor and the measurement time applied to measure the capacitance value of the second supercapacitor may be the same.

[0044] The method for determining the capacitance value of at least a first supercapacitor preferably comprises: - comparing the calculated capacitance value of the first supercapacitor 100 with a first predetermined minimum capacitance threshold.

[0045] For example, a minimum capacity threshold may be determined based on a maximum allowed wear value above which the first supercapacitor can no longer store enough energy to perform emergency braking.

[0046] When the comparison indicates that the calculated capacitance value of the first supercapacitor 100 is less than the predetermined minimum capacitance threshold, the method preferably further comprises: - transmitting a first maintenance request or alarm signal to a remote control station; and / or - activating first signalling means arranged in a control room of the vehicle, and / or - transmitting a first error message to a control unit of the vehicle; and / or - preventing release of the braking force generated by the electromechanical brake system.

[0047] In the railway sector, for example, a control means, i.e. a Train Control Unit (BCU), can communicate with a control of the vehicle, a Central Train Control Unit (TCMS). The communication can be via various means of communication, for example via hardware networks or bus networks (Ethernet, CAN, MVB, etc.).

[0048] In other words, if excessive consumption of the first supercapacitor is detected, intervention can be made, for example, by sending a first maintenance request or alarm signal to a remote control station, and / or by operating a first signaling means arranged in the control room of the vehicle, and / or by sending an error message to the control unit of the vehicle, and / or by preventing release of the braking force generated by the electromechanical brake system.

[0049] For example, the first signalling means may be visual or audible, for example an indicator light, LED, display, speaker or the like.

[0050] The method for determining the capacitance value of at least a first supercapacitor preferably comprises: - comparing the calculated capacitance value of the second supercapacitor 101 with a second predetermined minimum capacitance threshold.

[0051] The first predetermined minimum capacity threshold and the second predetermined minimum capacity threshold may preferably be equal.

[0052] When the comparison indicates that the calculated capacitance value of the second supercapacitor 101 is less than the second predetermined minimum capacitance threshold, the method preferably further comprises: - transmitting a second maintenance request or alarm signal to a remote control station; and / or - activating said first signalling means arranged in a control room of the vehicle or activating a second signalling means arranged in a control room of the vehicle, and / or - transmitting a second error message to a control unit of the vehicle; and / or - preventing release of the braking force generated by the electromechanical brake system.

[0053] For example, the second signalling means may be visual or audible, for example an indicator light, LED, display, speaker or the like.

[0054] In a further aspect, the present invention relates to an electromechanical braking system for at least one vehicle.

[0055] By way of example, a first embodiment of an electromechanical braking system is described below with reference to FIG.

[0056] In this first embodiment, the electromechanical braking system comprises: - a first supercapacitor configured to store a first amount of electrical energy sufficient to cause the brake system 102 to perform at least one emergency braking operation; - a second supercapacitor configured to store a second amount of electrical energy sufficient to cause the brake system 102 to perform at least one emergency braking operation; - control means 104 configured to execute the method for determining the capacitance value of the first supercapacitor according to any of the embodiments described above.

[0057] For example, the control means 104 may be a controller, a microcontroller, an electronic control unit, a control unit, a control module, a PLC, or the like.

[0058] For example, the control means may directly include timing means (e.g. timers) and / or means for measuring current (e.g. current sensors) and / or means for measuring voltage (e.g. voltage sensors), and may receive data from timing means and / or means for measuring current and / or means for measuring voltage external to said control means and coupled to respective elements of the electromechanical brake system, in order to make available various voltage, current and time data for performing a method for determining a capacitance value of a supercapacitor, such as at least a first voltage value at the terminals of the second supercapacitor, a second voltage value at the terminals of the first supercapacitor, a first voltage variation, a duration of a first measurement time interval, a first current value flowing in one of said terminals of the first supercapacitor, etc.

[0059] The electromechanical braking system may also preferably be configured to receive at least a portion of the third amount of energy from an electric energy supply means 106 of said vehicle. For example, the electric energy supply means 106 may be a battery of the vehicle.

[0060] The electromechanical braking system preferably comprises: - an electromechanical actuator 108 arranged to receive electrical energy and convert it into a braking force; at least one selection means 110 configured to receive at least a portion of a first amount of electric energy stored in the first supercapacitor, at least a portion of a second amount of electric energy stored in the second supercapacitor, and at least a portion of a third amount of electric energy stored in the supply means, and to selectively supply at least a portion of the first amount of electric energy stored in the first supercapacitor or at least a portion of the second amount of electric energy stored in the second supercapacitor or at least a portion of the third amount of electric energy stored in the electric energy supply means 106 to the electromechanical actuator 108.

[0061] In other words, for example, the selection means 110 may receive at least a portion of a first amount of electrical energy stored in the first supercapacitor, at least a portion of a second amount of electrical energy stored in the second supercapacitor, and at least a portion of a third amount of electrical energy stored in a vehicle battery, for selectively sending energy to an electromechanical actuator.

[0062] The first supercapacitor 100 and the second supercapacitor 101 may preferably be arranged electrically in parallel.

[0063] When the brake system receives a request to perform a braking action, the at least one selection means is preferably capable of selecting the following actions: - supplying at least a portion of a third amount of electrical energy stored in said electrical energy supply means 106 to said electromechanical actuator if the voltage at the terminals of said supply means is higher than said minimum voltage value.

[0064] In other words, when the braking system receives a request to perform a braking operation, the at least one selection means may preferably be adapted to provide at least a portion of the first amount of electrical energy stored in the first supercapacitor to the electromechanical actuator if the following conditions are met: the voltage at the terminals of said power supply means (e.g. a battery of the vehicle) (indicative of the energy stored in the battery) is below said minimum voltage value, i.e. emergency braking cannot be performed, but the voltage at the terminals of the first supercapacitor (indicative of the electrical energy stored in the first supercapacitor) is greater than said minimum voltage value.

[0065] Alternatively, when the braking system receives a request to perform a braking operation, the at least one selection means may be adapted to provide at least a portion of the second amount of electrical energy stored in the second supercapacitor to the electromechanical actuator, preferably if the following conditions are met: the voltage at the terminals of the power supply means (e.g. a battery of the vehicle) (indicative of the energy stored in the battery) is below said minimum voltage value, i.e. emergency braking cannot be performed, and the voltage at the terminals of the first supercapacitor (indicative of the electrical energy stored in the first supercapacitor) is below said minimum voltage value, i.e. emergency braking cannot be performed.

[0066] Furthermore, alternatively, when the brake system receives a request to perform a braking operation, the at least one selection means may preferably be adapted to provide at least a portion of a third amount of electric energy stored in the electric energy supply means 106 (e.g. a battery of the vehicle) to the electromechanical actuator if the following condition is met: the voltage at the terminals of said supply means 106 is greater than said minimum voltage value, i.e. emergency braking can be performed.

[0067] The control means may preferably be arranged to receive a signal indicative of a voltage value at the terminals of the electric energy supply means 106 (e.g. a vehicle battery). If the signal indicative of a voltage value at the terminals of the electric energy supply means 106 is below the minimum voltage value, the control means, via the selection means: - providing at least a portion of a first amount of electrical energy stored in the first supercapacitor to the electromechanical actuator; and / or providing at least a portion of a second amount of electrical energy stored in the second supercapacitor to the electromechanical actuator.

[0068] In other words, when the control means detects that the vehicle's battery has failed or is overused or damaged, said control means may operate the selection means to provide at least a portion of the first amount of electrical energy stored in the first supercapacitor and / or at least a portion of the second amount of electrical energy stored in the second supercapacitor to the electromechanical actuator.

[0069] With reference to FIG. 3, the selection means preferably comprises at least: a first diode 300 connected between said electrical energy supply means 106 and said electromechanical actuator, a second diode 302 connected between said first supercapacitor 100 and said electromechanical actuator 108, and a third diode 304 connected between said second supercapacitor 101 and said electromechanical actuator 108.

[0070] Alternatively, with reference to FIG. 4, the selection means may include at least: - first switching means 400 connected between said electrical energy supply means 106 and said electromechanical actuator, second switching means 402 connected between said first supercapacitor 100 and said electromechanical actuator 108, and third switching means 404 connected between said second supercapacitor 101 and said electromechanical actuator 108.

[0071] For example, each switching means may be a switch arranged to be switchable by said control means.

[0072] The electromechanical braking system preferably comprises: - communication means configured to send a first maintenance request or alarm signal to a remote control station and / or a second maintenance request or alarm signal to the remote control station and / or a first error message to a control unit of the vehicle and / or a second error message to the control unit of the vehicle; - at least one first signal means arranged in a control room of the vehicle; - means for preventing release of the braking force generated by the electromechanical brake system.

[0073] Below are some embodiments of the electromechanical braking system.

[0074] In the following, a possible embodiment of an electromechanical braking system comprising a first supercapacitor and a second supercapacitor is described. For example, the electromechanical braking system is configured to be installed in at least one rail vehicle. The electromechanical braking system comprises at least a first emergency supercapacitor configured to store a first electric energy and a second emergency supercapacitor configured to store a second electric energy. In this case, the first electric energy stored in the first supercapacitor and the second electric energy stored in the second supercapacitor, when provided to an electromechanical assembly of the braking system, are sufficient to generate a braking force suitable for actuating the electromechanical assembly to cause the braking system to perform at least one emergency braking operation.

[0075] For example, the electromechanical assembly may include an electric motor, and the braking force generated by the electromechanical assembly may be adjusted by actuating the electric motor. Also, the braking system may include a control means, a first connecting means, and a second connecting means.

[0076] The control means may be configured to selectively connect or disconnect the first emergency supercapacitor to or from the electric motor via said first connecting means so as to selectively supply electrical energy stored in the first emergency supercapacitor to the electric motor.

[0077] The control means may also be configured to selectively connect or disconnect the second emergency supercapacitor to or from the electric motor via said second connecting means so as to selectively supply electrical energy stored in the second emergency supercapacitor to the electric motor.

[0078] The electric motor may be configured to operate upon receiving said electrical energy from the first supercapacitor or from the second supercapacitor, and the electromechanical assembly may be configured to generate a braking force suitable to cause the brake system to perform at least one emergency braking operation.

[0079] For example, when the first emergency supercapacitor must store electrical energy, the control means may be configured to connect the first supercapacitor to at least one railcar battery. Alternatively, or in addition, the control means may be configured to connect the first emergency supercapacitor to an electrical energy recovery system included in or associated with the braking system. The electrical energy recovery system may be configured to recover electrical energy while the electromechanical assembly is applying a braking force.

[0080] For example, instead, when the second emergency supercapacitor must store electrical energy, the control means may be configured to connect the second supercapacitor to the at least one rail car battery. Alternatively, or in addition, the control means may be configured to connect the second emergency supercapacitor to an electrical energy recovery system included within or associated with the braking system.

[0081] For example, an electromechanical assembly: - a transmission shaft rotatably connected to the electric motor; - a linear actuator capable of extending from a retracted position in which the two ends of the linear actuator are at a first distance dis1 to an extended position in which the ends of the linear actuator are at a second distance dis2, the second distance being greater than the first distance dis1; - a transmission mechanism arranged between the transmission shaft and the linear actuator, the transmission mechanism being arranged to convert rotational motion of the transmission shaft into linear motion of the linear actuator.

[0082] For example, an electric motor: - rotating the transmission shaft in a first direction d1, by rotating the transmission shaft in the first direction d1, increasing the distance between the two ends of the linear actuator; The transmission shaft may be rotated in a second direction d2 opposite to said first direction d1, and by rotating the transmission shaft in the second direction d2, the distance between the two ends of the linear actuator may be reduced.

[0083] In one example, the braking force generated by the braking system may increase as the linear actuator moves from the first retracted position toward the extended position, or the braking force generated by the braking system may decrease as the linear actuator moves from the first retracted position toward the extended position.

[0084] In a further aspect, the present invention relates to a vehicle comprising the following elements: - electric energy supply means 106; - an electromechanical braking system 102 for at least one vehicle according to any one of the above mentioned embodiments.

[0085] The vehicle is preferably at least one rail car.

[0086] The vehicle is preferably a rail train.

[0087] The resulting advantage is therefore to provide a solution that allows monitoring the remaining capacity of a first supercapacitor of an electromechanical braking system of at least one vehicle without temporarily compromising the ability to perform emergency safety braking.

[0088] The invention is preferably applicable to any type of vehicle, which may include, for example, rail cars / trains, automobiles, trucks (e.g. highway semi-trailer trucks, mining trucks, trucks for transporting timber, etc.), and the route may be a track, a road, or a trajectory.

[0089] Various aspects and embodiments of a supercapacitor of at least one vehicle electromechanical braking system, an electromechanical braking system, and a vehicle equipped with this electromechanical braking system according to the present invention have been described. It is to be understood that each embodiment can be combined with any other embodiment. Moreover, the present invention is not limited to the described embodiments, but may be modified within the scope defined by the appended claims.

Claims

1. A method for determining a capacitance value of at least a first supercapacitor (100) of an electromechanical braking system (102) of at least one vehicle, comprising: the electromechanical braking system (102) further comprises a second supercapacitor (101); the first supercapacitor (100) is configured to store a first amount of electrical energy sufficient to cause the electromechanical brake system (102) to perform at least one emergency braking event; the second supercapacitor (101) is configured to store a second amount of electrical energy sufficient to cause the electromechanical brake system (102) to perform the at least one emergency braking operation; The method comprises: a) measuring a first voltage value at the terminals of the second supercapacitor (101); b) if the first voltage value is greater than a predetermined minimum voltage value, performing a charging or discharging operation of the first supercapacitor (100) during a first measurement time interval, the charging or discharging operation being configured such that the terminals of the first supercapacitor (100) assume a second voltage value; c) determining a first voltage variation at the terminals of the first supercapacitor (100) during the first measurement time interval; d) determining a first voltage change rate based on the first voltage change at the terminals of the first supercapacitor (100) determined in step c) and the duration of the first measurement time interval; e) measuring a first current value flowing through one of the terminals of the first supercapacitor (100) at a first measurement time point during the first measurement time period; f) calculating a capacitance value of the first supercapacitor (100) using the ratio between the first current value measured at the first measurement time and the first voltage change rate; The method of claim 1, further comprising:

2. The method described in claim 1, wherein step a) is performed when the second supercapacitor (101) is not undergoing a charging operation.

3. A method as described in claim 1 or claim 2, wherein step d) includes a step of determining the first voltage fluctuation rate using a ratio between the first voltage fluctuation determined in step c) and the duration of the first measurement time interval.

4. a') measuring a third voltage value at a terminal portion of the first supercapacitor (100); b') if the third voltage value is greater than the predetermined minimum voltage value, performing a charging or discharging operation of the second supercapacitor (101) during a second measurement time interval, the charging or discharging operation being configured such that the terminals of the second supercapacitor (101) assume a fourth voltage value; c') determining a second voltage variation at the terminals of the second supercapacitor (101) during the second measurement time interval; d') determining a second voltage change rate based on the second voltage change at the terminals of the second supercapacitor (101) determined in step c') and the duration of the second measurement time interval; e') measuring a second current value flowing through one of the terminals of the second supercapacitor (101) at a second measurement time point during the second measurement time period; f') calculating the capacitance value of the second supercapacitor (101) using the ratio between the second current value measured at the second measurement time and the second voltage change rate; The method of claim 1 or claim 2, further comprising:

5. The method of claim 4, wherein step a') is performed when the first supercapacitor (100) is not undergoing a charging operation.

6. The method of claim 4, wherein step d') includes determining the second voltage fluctuation rate using a ratio between the second voltage fluctuation determined in step c') and the duration of the second measurement time interval.

7. The method of claim 4, wherein the first measurement time interval and the second measurement time interval are equal.

8. The method of claim 1 or claim 2, further comprising the step of comparing the calculated capacitance value of the first supercapacitor (100) with a first predetermined minimum capacitance threshold.

9. The method of claim 8, wherein if the comparison indicates that the calculated capacitance value of the first supercapacitor (100) is less than the first predetermined minimum capacitance threshold, the method further comprises: transmitting a first maintenance request or alarm signal to a remote control station; and / or - activating a first signalling means arranged in a control room of the vehicle; and / or transmitting a first error message to a control unit of the vehicle; and preventing release of the braking force generated by the electromechanical brake system; The method of claim 8 further comprising:

10. The method of claim 9, further comprising the step of comparing the calculated capacitance value of the second supercapacitor (101) with a second predetermined minimum capacitance threshold.

11. The method of claim 10, wherein the first predetermined minimum capacity threshold and the second predetermined minimum capacity threshold are equal.

12. The method of claim 1, wherein if the comparison indicates that the calculated capacitance value of the second supercapacitor (101) is less than the second predetermined minimum capacitance threshold, transmitting a second maintenance request or alarm signal to a remote control station; and / or activating a first signaling means located in the control room of the vehicle or a second signaling means located in the control room of the vehicle; and transmitting a second error message to a control unit of the vehicle; and Preventing release of the braking force generated by the electromechanical brake system (102); The method of claim 10 further comprising:

13. An electromechanical braking system (102) for at least one vehicle, comprising: a first supercapacitor (100) configured to store a first amount of electrical energy sufficient to cause the electromechanical brake system (102) to perform at least one emergency braking event; a second supercapacitor (101) configured to store a second amount of electrical energy sufficient to cause the electromechanical brake system (102) to perform the at least one emergency braking operation; and Control means (104) for carrying out the method according to claim 1 or 2; 1. An electromechanical brake system comprising:

14. The electromechanical braking system adapted to receive at least a portion of a third amount of electrical energy from an electrical energy supply means (106) of the vehicle; The electromechanical brake system (102) an electromechanical actuator (108) arranged to receive and convert electrical energy into a braking force; at least one selection means (110) configured to receive at least a portion of the first amount of electrical energy stored in the first supercapacitor (100), at least a portion of the second amount of electrical energy stored in the second supercapacitor (100), and at least a portion of the third amount of electrical energy stored in the electrical energy supply means (106), and to selectively supply at least a portion of the first amount of electrical energy stored in the first supercapacitor, or at least a portion of the second amount of electrical energy stored in the second supercapacitor, or at least a portion of the third amount of electrical energy stored in the electrical energy supply means (106) to the electromechanical actuator; 14. The electromechanical braking system of claim 13, comprising:

15. The electromechanical brake system of claim 13, wherein the first supercapacitor (100) and the second supercapacitor are arranged electrically in parallel with each other.

16. The electromechanical brake system according to claim 15, wherein when the electromechanical brake system receives a request to apply braking, 15. The electromechanical brake system of claim 14, wherein the at least one selection means (100) is configured to supply at least a portion of the third amount of electrical energy stored in the electrical energy supply means (106) to the electromechanical actuator (108) when a voltage at the terminals of the electrical energy supply means (106) is greater than the minimum voltage value.

17. The selection means comprises at least a first diode (300) connected between said electrical energy supply means (106) and said electromechanical actuator, a second diode (302) connected between said first supercapacitor (100) and said electromechanical actuator (108), and a third diode (304) connected between said second supercapacitor (101) and said electromechanical actuator (108); Or, a first switching means (400) connected between said electrical energy supply means and said electromechanical actuator, a second switching means (402) connected between said supercapacitor (100) and said electromechanical actuator (108), and a third switching means (404) connected between said second supercapacitor (101) and said electromechanical actuator (108); 15. The electromechanical brake system of claim 14, comprising:

18. The control means adapted to carry out the method according to claim 12, The electromechanical brake system further comprises: communication means arranged to transmit the first maintenance request or alarm signal to a remote control station and / or the second maintenance request or alarm signal to a remote control station and / or the first error message to the control unit of the vehicle and / or the second error message to the control unit of the vehicle; and / or at least one first signalling means provided in a control room of said vehicle; and / or means for preventing release of the braking force generated by said electromechanical brake system; 15. An electromechanical brake system as claimed in claim 13 or claim 14, comprising:

19. The control means is adapted to receive a signal indicative of the voltage value at the terminals of the electrical energy supply means; when the signal indicating the voltage value at the terminals of the electrical energy supply means indicates a voltage value at the terminals of the electrical energy supply means (106) that is less than the minimum voltage value, The control means, via the selection means, providing at least a portion of the first amount of electrical energy stored in the first supercapacitor to the electromechanical actuator to apply automatic emergency braking; and / or providing at least a portion of the second amount of electrical energy stored in the second supercapacitor to the electromechanical actuator to apply automatic emergency braking.

15. The electromechanical brake system of claim 14 configured as follows:

20. An electrical energy supply means (106), An electromechanical brake system according to claim 13 or claim 14; A vehicle equipped with the above.

21. The vehicle of claim 20, comprising at least one rail car.

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