Power supply system, associated method and computer program

Abstract

Power supply system, method and associated computer program This power supply system (10) includes: a set of power battery(ies) (1) and a set of energy battery(ies) (2), such that the set of power battery(ies) (1) has a higher power density than the set of energy battery(ies) (2) and the set of energy battery(ies) (2) has a higher energy density than the set of power battery(ies) (1); a control block (8, 3, 6) adapted to control the distribution of energy between the set of power battery(ies) (1) and the set of energy battery(ies).The control block is adapted to limit the portion of power delivered by the energy battery set (2) to PmaxEnergy_discharge if the current power P to be supplied by the power supply system is greater than PmaxEnergy_discharge, and to have the remaining power, P – PmaxEnergy_discharge, delivered by the power battery set (1). Figure for the abbreviation: FIG 1.

Description

Title of the invention: Electric power supply system, method and computer program therefor

[0001] The present invention relates to the field of power supply systems comprising batteries. Such power supply systems are used in particular to power trains without catenary. However, the quantity of energy required is significant for long distances in autonomy, of the order of 500 kWh for 80 km of autonomy. The batteries used are generally power batteries, which are heavy and expensive. Since the batteries cannot be discharged every day to respect their lifespan, the power supply system must be oversized, by a factor of approximately two, increasing the weight and the price, or otherwise forcing a reduction in the autonomy distance.

[0002] There is therefore a need to have a power supply system that makes it possible to increase the autonomy of the powered machines while reducing the size and weight of the power supply system.

[0003] To this end, according to a first aspect, the invention proposes an electrical power supply system comprising:

[0004] - a set of power battery(ies) and a set of energy battery(ies) arranged in parallel, such that the set of power batteries has a higher power density than the set of energy batteries and the set of energy batteries has a higher energy density than the set of power batteries;

[0005] - a control block adapted to control the distribution of energy between the set of power battery(ies) and the energy battery assembly(s);

[0006] said power supply system being characterized in that the control block is adapted to, if the current power P to be supplied by the electrical power supply system is greater than PmaXEnergy_discharge, where PmaXEnergy_discharge is the value of the maximum power deliverable by the set of energy batteries, limit the portion of power delivered by the set of energy batteries to PmaxEnergy_dischargeCt to cause the set of power batteries to deliver the balance of power, P - PmaxF.nergi

[0007] The invention thus makes it possible to increase the autonomy of the powered machines while reducing the size and weight of the power supply system.

[0008] In embodiments, a power supply system according to the invention further comprises one or more of the following features:

[0009] - the control block is adapted to, if the current power P to be supplied by the electrical power supply system is less than PmaxEnergy_discharge, cause the set of energy batteries to deliver said power P; - the control block is adapted to, if the current electric braking power P to be stored by the electrical power supply system is less than PmaxPower_charge, OR PmaxPower_charge OSt the Value of the maximum power receivable by the set of power batteries, have the set of power batteries store said power P; - the control block is adapted to, if the current electric braking power P to be stored by the electrical power supply system is greater than the sum of PmaxPower_charge Ot of PmaxEnergy_c|large, OR PmuxPower_Charge OSt the value of the maximum power receivable by the set of power batteries and PmuxEnergy-Charge is the value of the maximum power receivable by the set of energy batteries, limit the power in the sets of batteries to a maximum threshold, the excess braking power required being ensured mechanically and / or thermally; - the control block is adapted to, if the current electric braking power P to be stored by the electrical power supply system is less than the sum of Pm^Energie-ch^ge and PmuxPuissiince-chiirge? and is greater than PmuxPuissiince-chiirge? where PmuxPuissiince-chiirge is the value of the maximum power receivable by the set of power battery(ies) and Pm^Energie-ch^ge is the value of the maximum power receivable by the set of energy battery(ies), store the product of k and P, kP, by the set of energy battery(ies), with predefined real k included in ]0,1 [, and (lk).P) by the set of power battery(ies); - k is equal to 0.5; and - the system is suitable for being transported on a support attached to a railway vehicle and suitable for powering said railway vehicle when it is in a traction situation and for recovering the energy from braking when it is in a braking situation. According to a second aspect, the present invention provides an electrical power supply method implemented by an electrical power supply system comprising: - a set of power battery(ies) and a set of energy battery(ies) arranged in parallel, such that the set of power battery(ies) has a higher power density than that of the set of energy battery(ies) and the set of energy battery(ies) has a higher energy density than that of the set of power battery(ies); - a control block adapted to control the distribution of energy between the set of power batteries and the set of energy batteries;

[0010] said electrical power supply method being characterized in that if the current power P to be supplied by the electrical power supply system is greater than PmaxEnergy.discharge, where PmaXEnergy_discharge is the value of the maximum power deliverable by the set of energy batteries, the control block limits the portion of power delivered by the set of energy batteries to PmaxEnergy_discharge and causes the set of power batteries to deliver the remaining power, P - Pm^pnergi

[0011] In embodiments, a power supply method according to the invention further comprises one or more of the following features: - if the current power P to be supplied by the electrical power supply system is less than PmaxEnergy_discharge, the control unit causes the set of energy batteries to deliver said power P; - if the current electric braking power P to be stored by the electrical power supply system is less than PmaxPower_charge? or PmaxPower_charge is the value of the maximum power receivable by the set of power batteries, the control unit causes the set of power batteries to store said power P; - if the current electric braking power P to be stored by the electrical power supply system is greater than the sum of PmaxPower_charge and PmaxEnergy_charge, where PmaxPower_charge is the value of the maximum power receivable by the set of power battery(ies) and PmaxEnergy_charge is the value of the maximum power receivable by the set of energy battery(ies), the control unit limits the power in the battery(ies) sets to a maximum threshold, the excess braking power required being ensured mechanically and / or thermally; - if the current electric braking power P to be stored by the electrical power system is less than the sum of PmaxEnergy_charge and PmaxPower_charge and CSt Greater than PmaxPower_charge, OR PmaxPower_charge is the value of the maximum power receivable by the set of power batteries and where PmaxEnergy_charge is the value of the maximum power receivable by the set of energy batteries, the control block causes the product of k and P, kP, to be stored by the set of energy batteries, with k predefined real value included in ]0,1[, and (lk).P by the set of power batteries; - k is equal to 0.5; and - the electrical power supply system is adapted to be transported on a support secured to a railway vehicle, the system supplying said railway vehicle when in traction mode and recovering energy from braking when in braking mode.

[0012] According to a third aspect, the present invention provides a computer program comprising software instructions which, when executed by a computer, implement a method as defined above.

[0013] These characteristics and advantages of the invention will appear on reading the description which follows, given solely by way of example, and made with reference to the appended drawings, in which:

[0014] [Fig-1] [Fig.l] represents a schematic view of a power supply system in an embodiment of the invention;

[0015] [Fig.2] [Fig.2] is a flowchart of steps implemented in a mode of realization of the invention.

[0016] [Fig.l] shows a power supply system 10 in one embodiment of the invention.

[0017] The power supply system 10 according to the invention is, in the embodiment considered, embedded in a tender, that is to say in a car dedicated to receiving the power supply system and generally positioned just behind a motor car to be supplied with electrical energy. In other embodiments, the system 10 is for example integrated in boxes in the roof of the train, or inside the train or under the floor of the train...

[0018] It will be noted that the invention is also applicable to trains with distributed propulsion (without a motor).

[0019] The power supply system 10 is adapted, in a first operating mode, to deliver, in the manner described below, electrical energy to the train, which is used by a set of electrical equipment 20 (the traction motor of the train locomotive, the auxiliary equipment, etc.).

[0020] The power supply system 10 is adapted, in a second operating mode, to receive electrical energy and to store the latter, in the manner described below.

[0021] The power supply system 10 comprises, in the case considered, a set of power battery(ies) BattP 1, a set of energy battery(ies) 2, two DC / DC converters 3 and 6 and an electronic control device 8.

[0022] The power battery assembly 1 comprises a power battery or several branches of power batteries, arranged in parallel. Each battery branch has at its terminals the nominal voltage of the battery. In the majority of cases, this electrical branch is constituted by a pack (mechanical box removable in line), single battery, but in certain cases, the battery branch may be made up of packs connected in series. Subsequently, we will refer to the power battery 1 to designate the set of power battery(ies).

[0023] The BattEn 2 energy battery assembly comprises one or more energy batteries, arranged in parallel. Each battery branch has the nominal voltage of the battery at its terminals. In the majority of cases, this electrical branch is made up of a pack (mechanical box removable in line), a single battery, but in certain cases the battery branch may be made up of packs placed in series. Hereinafter, we will refer to the energy battery 2 to designate the energy battery assembly 2.

[0024] As is known, a battery is a set of rechargeable electric accumulators connected together so as to create an electric generator of desired voltage and capacity.

[0025] The accumulator battery makes it possible to store electrical energy in chemical form and to restore it in the form of direct current, in a controlled manner.

[0026] The BattEn 2 energy battery has a higher energy density (i.e. energy per unit of weight or size, thus expressed in kWh / kg or kWh / 1) than the BattP 1 power battery, for example at least 50% higher. For example, the BattEn 2 energy battery is a battery made up of a NMC Lithium ion cell characterized by an energy density of 200 Wh / kg. The BattP 1 power battery is a battery made up of a Titanate-Lithium cell of approximately 70 Wh / kg.

[0027] The BattP 1 power battery has a power density (i.e. an electrical power per unit of weight or size, thus expressed in kW / kg or kW / 1) higher than the BattEn 2 energy battery, for example higher by at least 100%. An energy battery is capable of delivering approximately 170kWmax per tonne while a power battery is at 400kW per tonne. This ratio is also found in the other direction for energy, namely the energy density of an energy battery is around 130kWh per tonne while for a power battery it is only 50kWh per tonne.

[0028] The power battery BattP 1 is connected to the DC / DC converter 3.

[0029] The energy battery BattEn 2 is connected to the DC / DC converter 6.

[0030] The power supply / storage chain comprising the DC / DC converter 3 and the power battery BattP 1 is arranged in parallel with the power supply / storage chain comprising the DC / DC converter 6 and the energy battery BattEn 2.

[0031] The input of the DC / DC converter 3 is connected to the consumer equipment 5 in the train, via a Traction bus (for the train's motor consumer equipment) or an Auxiliary bus (for auxiliary consumer equipment such as air conditioning, heating, etc.). The exchanges of electrical energy between the train and the power supply system 10 are done via these buses, each comprising a high voltage power supply cable (typically between 700 and 3000 V) which plays the role of local “catenary” and through isolation contactors 4, 7.

[0032] The isolation contactor 4 is adapted to isolate, when it is commanded to open, the chain comprising the DC / DC converter 3 and the power battery Battp 1, the isolation contactor 7 is adapted to isolate, when it is commanded to open, the chain comprising the DC / DC converter 6 and the energy battery BattEn 2.

[0033] The DC / DC converter 3 via its control software is adapted to control the charging and discharging of the power battery Battp 1, i.e. to modulate the charging and discharging power.

[0034] The DC / DC converter 6 via its control software is suitable for controlling the charging and discharging of the BattEn 2 energy battery.

[0035] The electronic control device 8 is adapted to define the power distribution of the 2 energy sources by defining the operation of the DC / DC 3 and DC / DC 6 converters, and thus to control the charging and discharging of each of the power batteries Battp 1 and energy batteries BattEn 2.

[0036] In the embodiment considered, the electronic control device 8 comprises a memory and a processor (not shown) such that the memory comprises software instructions, which, when executed on the processor, implement the steps described below with reference to [Fig.2] and incumbent on the control device 8.

[0037] In [Fig.2], the set 100 of steps of a power supply method in one embodiment of the invention is described.

[0038] The control device 8 determines the energy distribution in the manner described in [Fig.2], then controls the two DC / DC converters 3 and 6 to implement this energy distribution, with respective current setpoints to carry out this energy distribution.

[0039] In a step 101, the control device 8 identifies whether the operating mode is a traction mode (i.e. a mode where electrical energy must be supplied to the train by the power supply system 10) or a braking mode (electrical energy, following braking of the train, is supplied to the power supply system 10 from the train).

[0040] If the identified operating mode is the traction mode, in a step 102, the control device 8 determines the current value P of the power required by the train from the power supply system 10 coming from the driving manipulator then compares this power P to a value PmaxEnergy .discharge-

[0041] The PmaxEnergie .discharge value is the maximum power value deliverable by the BattEn 2 energy battery determined by the capacity of the installed battery and the instantaneous conditions of the battery (state of charge, cell temperature). It is therefore a value that the battery management system, or BMS (from the English "Battery Management System"), calculates continuously and not a fixed value (its variation range is however fixed).

[0042] In the event of high power required, i.e. if P > PmaxEnergy .discharge, in a step 103, the control device 8 establishes the setpoints of the converters 3 and 6 so that the power supplied PI by the energy battery BattEn 2 is limited to PmaxEnergy .discharge (PI = PmaxEnergy .discharge), and that the remainder P2 of the required power (P2 = P - PI) is supplied by the power battery BattP 1.

[0043] Since two batteries are installed, the power battery has limited power due to its limited volume / mass. It cannot therefore provide the total maximum power on its own. The energy battery, which is already present, therefore provides the other part of the total power.

[0044] In the event of low power required, i.e. if P < PmaxEnergie .discharge, in a step 104, the control device controls the converters 3 and 6 so that all the required power P is supplied by the energy battery BattEn 2.

[0045] The advantage of this arrangement rather than having the maximum delivered by the BattP 1 power battery is that, taking into account the differences in energy density between a BattEn energy battery and a BattP power battery, it is often impossible to satisfy the energy needs on a journey by a power battery (too heavy, too bulky).

[0046] If the identified operating mode is the braking mode, in a step 105, the control device 8 determines the current value P of the electrical power coming from the braking by the train and delivered to the power supply system 10 from the driving manipulator then compares this power P to a value Pmax P uissance_charge , where PmaxP uissance.charge is the value of the maximum power receivable by the set of power battery(ies) 1.

[0047] In the event of low braking power delivered, ie if Pbraking Pmax power .load (where Pfeinage is the delivered braking power), in a step 106, the control device 8 establishes the instructions of the converters 3 and 6 so that all the delivered braking power P is supplied to the power battery BattP 1 for storage by the latter.

[0048] The interest is to recharge as much as possible the power battery which will be used in the next traction phase (discharge) and which has a small capacity. Moreover, this cycle recharging has less impact in terms of lifespan on the power battery than on the energy battery which is less “cyclable” than the power battery.

[0049] In the case of average braking power, i.e. if (PmaxEnergy_charge+ Pmax power_charge)> P > PmaxPower_charge (where PmaxEnergy_charge is the value of the maximum power receivable by the set of energy batteries 2), in a step 107, the control device 8 establishes the instructions for the converters 3 and 6 so that the power is distributed between the 2 types of battery:

[0050] - a percentage of the power supplied, i.e. the product of an index k and the power supplied P, kP is supplied to the energy battery BattEn 2 (with real k included in ]0,l[; for example, in the case considered, k = 0.5);

[0051] - the remainder of the supplied power, i.e. (lk).P is delivered to the power battery Battp 1.

[0052] The advantage of this arrangement is, in this case where the braking power exceeds the maximum power of the power battery, to send the excess to the energy battery.

[0053] In the case of high braking power, i.e. if P > Pmax P uissance _chaige + PmaxEnergie charge, the control device 8 controls the converters 3 and 6 so as to limit the power in the 2 batteries to a maximum threshold, for example equal to the sum of PmaxPuiSsance_char ge and PmaxEnergie_charge- The excess braking power required is ensured mechanically and / or thermally, for example by the mechanical brake and no longer the electrical braking and / or by heat dissipation in a rheostat of the vehicle.

[0054] The control block 8, 3, 6, is adapted to, if the current electric braking power P to be stored by the electrical power supply system is greater than the sum of PmaxPower_charge ^t of PmaxEnergy_cEarge, OR PmaxPower_charge ^St the value of the maximum power receivable by the set of power batteries 1 and PmaxEnergy^arap is the value of the maximum power receivable by the set of energy batteries 2, limit the power in the sets of batteries 1, 2, to a maximum threshold, the excess braking power required being ensured mechanically and / or thermally.

[0055] The invention thus proposes a power supply system separated into two parts and controllable as described above, which provides a distribution solution between the two types of battery in the power supply and storage situation making it possible to increase the ratio of autonomy distance to size of the power supply system.

[0056] In the power supply system 10, the power battery BattP makes it possible to absorb the power peaks required by the train, while the energy battery BattEn makes it possible to absorb the auxiliary energy variations required (linked for example to seasonal variation).

[0057] Compared to a solution of supercapacitors combined with a battery, the proposal with two types of battery according to the invention makes it possible to offer longer power peaks than those which could be offered with a supercapacitor. The supercapacitor is generally used for charging or discharging times of the order of 30s to 1min, it could allow a train to start, but not to cross a slope which would require a longer supply of power and therefore more energy

[0058] Compared to a fuel cell solution combined with supercapacitors, we find the same remark for the supercapacitor which, for a train, has the disadvantage of being limited in energy and therefore of not being able to offer power over a sufficiently long period.

[0059] For this same comparison with a solution comprising a fuel cell combined with supercapacitors, the difference between the fuel cell and the energy battery is the size of the system which is much smaller and lighter in the case of the energy battery than a fuel cell system including bulky tanks. The limit being with the energy battery, the storable energy. Today we have a limit of 80-100 km of autonomy for a pure battery system, where a fuel cell solution allows 400 to 1000 km of autonomy, to the extent that the space for integration is available

[0060] In another embodiment, the electronic control device 8 is produced in the form of a programmable logic component, such as an FPGA (Field Programmable Gate Array), or in the form of a dedicated integrated circuit, such as an ASIC (Applications Specific Integrated Circuit).

[0061] The invention has been described above with reference to a railway train application, but it is applicable to any situation where an electrical power supply and / or electrical storage system is adapted to supply and / or store energy, for example a tram or even an electric bus.

Claims

Claims

1. Power supply system (10) comprising: - a set of power batteries (1) and a set of energy batteries (2) arranged in parallel, such that the set of power batteries (1) has a higher power density than that of the set of energy batteries (2) and the set of energy batteries (2) has a higher energy density than that of the set of power batteries (1); - a control block (8, 3, 6) adapted to control the distribution of energy between the set of power batteries (1) and the set of energy batteries;the control block being adapted to, if the current power P to be supplied by the electrical power supply system is greater than PmaxEnergy_discharge, OR PmaxEnergy_discharge OSt the value of the maximum power deliverable by the set of energy batteries (2), limit the part of the power delivered by the set of energy batteries (2) to PmaxEnergy_discharge and cause the power balance, P - Pm, to be delivered by the set of power batteries (1), said power supply system being characterized in that the control block (8,3,6) is further adapted to, if the current electrical braking power P to be stored by the electrical power supply system is less than Pmax Power_charge, OR PmaxPower_charge is the value of the maximum power receivable by the set of power batteries (1), cause the set of power batteries (1) to store the balance of power, P - Pm, ... power (1), said current electric braking power P.;

2. Electrical power supply system (10) according to claim 1, in which the control block (8, 3, 6) is adapted to, if the current power P to be supplied by the electrical power supply system is less than PmaxEnergy_discharge, cause the set of energy batteries (2) to deliver said power P.

3. An electrical power supply system (10) according to any preceding claim, wherein the control unit (8, 3, 6) is adapted to, if the current electrical braking power P to be stored by the electrical power supply system is greater to the Sum of PmaxPower_charge ofPmaxEnergy_charge? OR PmaxPower_charge is the value of the maximum power receivable by the set of power battery(ies) (1) and PmaxEnergy_charge is the value of the maximum power receivable by the set of energy battery(ies) (2), limit the power in the sets of battery(ies) (1, 2) to a maximum threshold, the excess braking power required being ensured mechanically and / or thermally.

4. Electrical power supply system (10) according to one of the preceding claims, wherein the control block (8, 3, 6) is adapted to, if the current electrical braking power P to be stored by the electrical power supply system is less than the sum of P maxEnergie _chargeOt of Pmax P uissance_charge, Ot CSt Greater than PmaxPuiSSance_charge, where PmaxP uiSSance_charge is the value of the maximum power receivable by the set of power batteries (1) and PmaxEnergie_charge is the value of the maximum power receivable by the set of energy batteries (2), store the product of k and P, kP, by the set of energy batteries (2), with predefined real k included in ]0,1[, and (lk).P by the set of power batteries (1).

5. The power supply system (10) of claim 4, wherein k is 0.

5.

6. Electrical power supply system (10) according to one of the preceding claims, adapted to be transported on a support secured to a railway vehicle and adapted to power said railway vehicle when it is in a traction situation and to recover the energy from braking when it is in a braking situation.

7. An electrical power supply method implemented by an electrical power supply system (10) comprising: - a set of power batteries (1) and a set of energy batteries (2) arranged in parallel, such that the set of power batteries (1) has a higher power density than that of the set of energy batteries (2) and the set of energy batteries (2) has a higher energy density than that of the set of power batteries (1); - a control block (8, 3, 6) adapted to control the distribution of energy between the set of power batteries (1) and the set of energy batteries; wherein if the current power P to be supplied by the electrical power supply system is greater than PmaxEnergy_discharge, where PmaxEnergy_discharge is the value of the maximum power deliverable by the set of energy batteries (2), the control block limits the portion of power delivered by the set of energy batteries (2) to PmaxEnergy_discharge and causes the set of power batteries (1) to deliver the remaining power, P - PmaXEnergy_discharge, and said electrical power supply method being characterized in that, if the current electrical braking power P to be stored by the electrical power supply system is less than Pmax Power ch^ge, where PmaxPower-churge is the value of the maximum power receivable by the set of power batteries (1), the control block (8, 3, 6) causes the set of power batteries (1) to store said current electric braking power P.

8. Electrical power supply method according to claim 7, wherein if the current power P to be supplied by the electrical power supply system is less than Pm^Energy-discharge^ge, the control block (8, 3, 6) causes the set of energy batteries (2) to deliver said power P.

9. A computer program comprising software instructions which, when executed by a computer, implement a method according to any one of claims 7 to 8.

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