Method for prioritization of electrical power supply of in-vehicle networks

Abstract

An aspect of the invention relates to a prioritization method (100) for prioritizing the electrical powering of an on-board network with respect to the recharging of a vehicle battery, the method (100) comprising: - an activation step (101) for activating by a computer the prioritization of the electrical powering of the on-board network when the following conditions are verified: - an estimated charging rate percentage of an electrical energy generator greater than or equal to a predetermined maximum charging rate, - an estimated current of an electrical energy storage greater than or equal to a predetermined activation current, and - no intentional saturation request for intentionally saturating the electrical energy generator being requested, - a determination step (102) for determining a voltage to be applied by the electrical energy generator to the terminals of the electrical energy storage, - a transmission step (103) for transmitting by the computer a maximum voltage set value, the maximum voltage set value being equal to the determined voltage to be applied to the terminals of the electrical energy storage.

Description

Technical Field

[0001] This invention claims priority to French application No. 2001728, filed on February 21, 2020, the contents of which (text, drawings and claims) are incorporated herein by reference.

[0002] One aspect of the invention relates to a prioritization method for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of the vehicle's (especially a motor vehicle's) electrical energy storage. Another aspect of the invention relates to a vehicle (especially a motor vehicle) configured and arranged to implement the steps of the prioritization method for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of the vehicle's electrical energy storage. Background Technology

[0003] During the charging of an energy storage device (which is, for example, formed by a vehicle battery), excessive current may be generated by the charger, which inevitably alters the battery's lifespan. A charging method for charging a motor vehicle battery is known from patent application WO2018 / 205425A1, which aims to address the risk of changes in motor vehicle battery lifespan caused by excessive current.

[0004] Also known from document FR3001931A1 is a vehicle-mounted circuit comprising an electric generator, a battery, and a power management system, the power management system including limiting components for limiting voltage and current applied to the battery, the battery integrating a minimum voltage constraint applied to an on-board network.

[0005] Also known from document DE102014208999A1 is a vehicle-mounted electrical system comprising two batteries, wherein energy in braking mode is recovered to recharge the two batteries. The voltage at the terminals of the battery mounted in parallel with the generator is maintained below a limit value.

[0006] However, this method cannot solve the saturation problem of the power generator used to recharge the power battery of the motor vehicle on the one hand and to power the components of the vehicle's on-board network on the other hand.

[0007] In fact, if the use of 12V lithium-ion battery packs (e.g., auxiliary batteries in the automotive sector) offers significant advantages, the inherent internal resistance of this type of battery pack can naturally generate very high charging currents if these currents are not actively controlled. This can become problematic when a less powerful generator is used to power both the vehicle's onboard network and the 12V lithium-ion battery pack. Because the current of the charging 12V battery pack is uncontrolled, this can lead to unintended saturation of the generator and insufficient power to supply the components of the onboard network. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art by providing a prioritization method for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of a vehicle battery, wherein the prioritization method can recharge the energy storage device without affecting the electrical power supply of the components of the in-vehicle network.

[0009] In this context, the present invention thus relates, in its broadest sense, to a prioritization method for prioritizing the electrical power supply of an onboard network relative to the recharging of the energy storage of a vehicle (especially a motor vehicle), the method comprising: - An activation step, which is used to activate the priority of electrical power supply to the in-vehicle network by a computer when the following conditions are verified: - The estimated charge ratio percentage of the power generator is greater than or equal to the predetermined maximum charge ratio. - The estimated current of the energy storage device is greater than or equal to the predetermined activation current, and - No request was made for the intentional saturation of the power generator in order to recover vehicle kinetic energy. - A determination step, wherein the determination step is used to determine the voltage that needs to be applied by the power generator to the terminals of the power storage device. - A transmission step, wherein the computer transmits a maximum voltage setting value, the maximum voltage setting value being equal to a determined voltage to be applied to the terminals of the energy storage device.

[0010] According to this invention, the electrical power supply of the vehicle network is prioritized relative to the recharging of the vehicle battery based on the stress level of the power generator and the charging level of the energy storage device. This prioritization is implemented by managing the voltage at the terminals of the energy storage device. The energy storage device may be formed, for example, by at least one 12V lithium-ion battery or lead-acid battery. This prioritization ensures that the recharging of the vehicle battery does not affect the power supply to the components of the vehicle network.

[0011] In addition to the features mentioned in the preceding paragraph, a priori method for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of an energy storage device, according to one aspect of the invention, may have one or more additional features from the following features, which may be considered individually or in all possible combinations.

[0012] According to one aspect of the invention, if the determined voltage to be applied to the terminals of the energy storage device is greater than a predetermined maximum voltage of the energy storage device, then the maximum voltage setting is equal to the predetermined maximum voltage of the energy storage device.

[0013] According to one aspect of the invention, the determined voltage to be applied to the terminals of the energy storage device depends on: - The estimated internal resistance of the energy storage device, - The estimated no-load voltage of the energy storage device - The estimated temperature of the energy storage device, and - The estimated state of charge of the energy storage device.

[0014] According to one aspect of the invention, the estimated open-circuit voltage of the energy storage device is OCVse = Use - (Ise) Rse), where: - Use = the estimated voltage of the energy storage device, and - Ise = the estimated current of the energy storage device.

[0015] According to one aspect of the invention, the voltage to be applied to the terminals of the energy storage device is determined to be equal to OCVse + (Rse) Ise_I), where Ise_I = the limiting current of the energy storage device, the limiting current depending on the estimated state of charge of the energy storage device and the temperature of the energy storage device.

[0016] According to one aspect of the invention, the method includes a stopping step, the stopping step being used by the computer to stop the application of the maximum voltage setpoint if the estimated charge ratio percentage of the electrical generator is less than or equal to a predetermined maximum desaturation charge ratio and the estimated current of the energy storage is less than or equal to a predetermined deactivation current of the energy storage.

[0017] According to one aspect of the invention, the method includes a stopping step, the stopping step being used by the computer to stop the application of the maximum voltage setpoint if a request for intentional saturation of the power generator in order to recover vehicle kinetic energy is requested.

[0018] According to one aspect of the invention, the energy storage device is a 12V lithium-ion storage device.

[0019] According to one aspect of the invention, the power generator is a rotating electric motor or a system including at least one power storage device and a converter, the converter being constructed and configured to convert DC voltage into different DC voltages.

[0020] On the other hand, the present invention relates to a vehicle (especially a motor vehicle) configured and arranged to implement steps of a prioritization method according to at least one of the above embodiments for prioritizing the electrical power supply of an on-board network relative to the recharging of a vehicle battery. Attached Figure Description

[0021] The invention will be better understood by reading the detailed description and accompanying drawings, in which: Figure 1 The illustration schematically depicts a prioritization method according to an embodiment of the present invention for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of the vehicle's energy storage.

[0022] Figure 2 An embodiment of a vehicle conforming to one aspect of the invention is illustrated schematically, the vehicle being constructed and configured to implement steps of a prioritization method for prioritizing the electrical power supply to the on-board network relative to the recharging of the vehicle's energy storage. Detailed Implementation

[0023] The descriptions below are to be referenced without distinction. Figure 1 and Figure 2 .

[0024] Figure 1 An example of an implementation of a priori method 100 for prioritizing the electrical power supply of an in-vehicle network relative to the recharging of the vehicle's energy storage is shown, according to one aspect of the invention.

[0025] Figure 2 This illustrates another aspect of the invention, relating to a vehicle 1 constructed and configured to implement a prioritization method 100, conforming to the invention, for prioritizing the electrical power supply to an onboard network relative to the recharging of the vehicle's energy storage. For this purpose, vehicle 1 includes: - Energy storage device 2, - Electrical generator 3, - Controller 4, and - Computer 5.

[0026] The method 100 includes an activation step 101, which is used to activate the priority of electrical power supply to the vehicle network by the computer 5 when the following conditions are verified: - The estimated charge ratio percentage RCOpe of the power generator is greater than or equal to the predetermined maximum charge ratio RCO_m. - The estimated current Ise of the energy storage device is greater than or equal to the predetermined activation current IA, and - No intentional saturation request DL for intentionally saturating the power generator 3 has been requested.

[0027] The intentional saturation request DL can be executed, for example, during regenerative braking, in which an electrical energy generator 3 formed by a rotating motor converts mechanical energy into electrical energy to recharge the energy storage 2.

[0028] In one embodiment, the energy storage device 2 is formed from a 12V lithium-ion battery. The energy generator 3 can be an alternator or a rotating motor of the AC starter type. In different embodiments, the energy generator 3 can be formed from a system including an energy storage device and a converter constructed and configured to convert DC voltage into different DC voltages. For example, this type of system is capable of converting 48V or 300V voltage to 12V voltage.

[0029] The predetermined maximum charge ratio RCO_m is formed by the percentage of the maximum charge ratio, from which the power generator is considered to be saturated. For example, the predetermined maximum charge ratio RCO_m can be fixed at 95%.

[0030] The predetermined activation current IA is formed by the current of the energy storage device. Above this current, the current drawn from the 12V storage device needs to be limited to desaturate the generator through an activation priority strategy. For example, the predetermined activation current IA can be fixed at 20A.

[0031] The three conditions required for the priority step 101 of the vehicle network's electrical power supply are verified by computer 5. For this purpose, the estimated charge ratio percentage RCOpe of the power generator is transmitted from power generator 3 to computer 5. The estimated current Ise of the energy storage is transmitted from energy storage 2 to computer 5. If no intentional saturation request DL is transmitted from controller 4 to computer 5, computer 5 can trigger step 101. This priority strategy is activated only if the management system for the overall management of the vehicle's 12V electrical power does not intentionally saturate the power generator in order to recover vehicle kinetic energy. This is especially true during the ballast phase of the alternator (which is used to implement energy recovery during deceleration or braking).

[0032] The activation step 101, which prioritizes the electrical power supply to the vehicle network relative to the recharging of the energy storage, can detect the saturation stage of the vehicle's 12V power generator and determine the authorization for activation of the priority strategy by limiting the current drawn from the 12V storage.

[0033] Once activation step 101 is triggered, method 100 includes step 102, which is used to determine the voltage Upe that needs to be applied by the power generator to the terminals of the power storage.

[0034] The method 100 further includes step 103, which is used to transmit a maximum voltage setting value Upe_m by the computer 5, the maximum voltage setting value Upe_m being equal to the determined voltage Upe that needs to be applied by the power generator 3 to the terminals of the power storage 2.

[0035] It should be noted that without any control strategy to manage this current, the 12V lithium-ion energy storage tends to draw maximum current from the power generator 3 for charging, which is undesirable, especially when the power generator 3, with its relatively weak capacity, also needs to power the vehicle network. The maximum voltage setting Upe_m determines the limiting voltage to be considered at the 12V lithium-ion battery location, specifically to desaturate the power generator 3 and allow for proper power supply to the vehicle network. For this purpose, the current drawn by this type of 12V lithium-ion energy storage is limited.

[0036] According to one aspect of the invention, if the determined voltage Upe to be applied to the terminal of the energy storage device is greater than the predetermined maximum energy storage device voltage Use_m, then the maximum voltage setting Upe_m is equal to the predetermined maximum energy storage device voltage Use_m.

[0037] The pre-determined maximum energy storage voltage Use_m is a battery voltage setting value determined to maximize various requirements and constraints, particularly such as battery durability, energy recovery, or the performance of some components of the vehicle network. This selection thus produces a battery limit voltage that must be considered by the overall energy management system to subsequently determine the prioritized maximum voltage setting Upe_m that must be applied by the energy generator to the terminals of the energy storage.

[0038] According to one aspect of the invention, the determined voltage Upe to be applied to the terminals of the energy storage device depends on: - The estimated internal resistance Rse of the energy storage device, - The estimated no-load voltage OCVse of the energy storage device, - The estimated temperature Tse of the energy storage device, and - The estimated state of charge (SOCse) of the energy storage device.

[0039] The estimated internal resistance Rse of the energy storage device is estimated based on the temperature of the 12V lithium-ion battery. For example, the estimated internal resistance Rse of the energy storage device can be determined by the computer 5 using a pre-established mapping. To this end, the energy storage device 2 transmits its own temperature Tse to the computer 5.

[0040] According to one aspect of the invention, the estimated open-circuit voltage of the energy storage device is OCVse = Use - (Ise) Rse), where: Use = the estimated voltage of the energy storage device 2, and Ise = the estimated current of the energy storage device 2.

[0041] The estimated open-circuit voltage OCVse of the energy storage device is estimated by the computer 5. Therefore, the energy storage device 2 transmits its estimated voltage Use and its estimated current Ise to the computer 5.

[0042] The estimated no-load voltage can then be filtered using, for example, a first-order low-pass filter to obtain noise-processed information.

[0043] According to one aspect of the invention, the determined voltage Upe to be applied to the terminals of the energy storage device is equal to OCVse + (Rse) Ise_I), where: - Ise_I = the limiting current of the energy storage device, which depends on the estimated state of charge SOCse of the energy storage device and the temperature Tse of the energy storage device.

[0044] The limiting current Ise_I of the energy storage device can be determined by the computer 5 using a predetermined mapping, which depends on the estimated state of charge SOCse of the energy storage device and the temperature Tse of the energy storage device. For this purpose, the energy storage device 2 transmits its own temperature Tse and its own estimated state of charge SOCse to the computer 5.

[0045] The purpose of this calculation is to determine the authorized maximum voltage at the terminals of the 12V lithium-ion energy storage device based on the required maximum target current for the energy storage device 3. This current can be a positive (charging), zero (holding charge), or negative (battery discharging) maximum current.

[0046] According to one aspect of the invention, the method 100 includes step 104, which is used to stop the application of the maximum voltage setpoint Upe_m if: - The estimated charge ratio percentage RCOpe of the electrical generator is less than or equal to the predetermined maximum desaturation charge ratio RCOd_m and the estimated current Ise of the energy storage is less than or equal to the predetermined deactivation current Ise_D of the energy storage, or - A request for intentional saturation of the power generator 3 has been made.

[0047] The predetermined maximum desaturation charge ratio RCOd_m is the percentage of the maximum charge ratio from which the power generator 3 no longer stably remains at saturation. For example, the predetermined maximum desaturation charge ratio RCOd_m can be fixed at 70%.

[0048] The predetermined deactivation current Ise_D of the energy storage device is the current of the energy storage device, below which the desaturation strategy of the electrical generator 3 may be deactivated. For example, the deactivation current Ise_D of the energy storage device can be fixed at 5A.

[0049] Typically, due to the present invention, when it is desired to sized the vehicle power generator 3 using lithium-ion memory as appropriately as possible for economic reasons, the current drawn from the electrical memory 2 can be controlled.

Claims

1. A prioritization method (100) for prioritizing the electrical power supply of an on-board network relative to the recharging of the vehicle's electrical energy storage device (2), characterized in that, The prioritization method (100) includes: - Activation step (101), the activation step being used by computer (5) to activate the priority of electrical power supply to the vehicle network when the following conditions are verified: The estimated charge ratio percentage RCOpe of the power generator is greater than or equal to the predetermined maximum charge ratio RCO_m. The estimated current Ise of the energy storage device is greater than or equal to the predetermined activation current IA, and No intentional saturation request (DL) was requested for intentionally saturating the power generator (3) in order to recover vehicle kinetic energy; - Determining step (102), the determining step being used to determine the voltage Upe to be applied by the power generator (3) to the terminals of the power storage (2); - Transmission step (103), the transmission step being used by the computer (5) to transmit a maximum voltage setting Upe_m, the maximum voltage setting Upe_m being equal to the determined voltage Upe to be applied to the terminal of the energy storage (2).

2. The prioritization method (100) according to claim 1, characterized in that, When the voltage Upe to be applied to the terminal of the energy storage device (2) is greater than the predetermined maximum voltage Use_m of the energy storage device, the maximum voltage setting Upe_m is equal to the predetermined maximum voltage Use_m of the energy storage device.

3. The prioritization method (100) according to claim 1 or 2, characterized in that, The voltage Upe to be applied to the terminals of the energy storage device depends on: - The estimated internal resistance Rse of the energy storage device, - The estimated no-load voltage OCVse of the energy storage device, - The estimated temperature Tse of the energy storage device, and - The estimated state of charge (SOCse) of the energy storage device.

4. The prioritization method (100) according to claim 3, characterized in that, The estimated open-circuit voltage of the energy storage device is OCVse = Use - (Ise). Rse), where - Use = the estimated voltage of the energy storage device, and - Ise = the estimated current of the energy storage device.

5. The prioritization method (100) according to claim 3, characterized in that, The voltage Upe to be applied to the terminals of the energy storage device is determined to be equal to OCVse + (Rse). Ise_I), where - Ise_I = the limiting current of the energy storage device, which depends on the estimated state of charge SOCse of the energy storage device and the temperature Tse of the energy storage device.

6. The prioritization method (100) according to any one of claims 1, 2, 4 and 5, characterized in that, The prioritization method includes a stop step (104), which is used by the computer (5) to stop applying the maximum voltage setting Upe_m when the estimated charge ratio percentage RCOpe of the power generator is less than or equal to the predetermined maximum desaturation charge ratio RCOd_m and the estimated current Ise of the power storage is less than or equal to the predetermined deactivation current Ise_D of the power storage.

7. The prioritization method (100) according to any one of claims 1, 2, 4 and 5, characterized in that, The prioritization method includes a stop step (104) for the computer (5) to stop the application of the maximum voltage setting Upe_m when a request for intentional saturation of the power generator (3) in order to recover vehicle kinetic energy is requested.

8. The prioritization method (100) according to any one of claims 1, 2, 4 and 5, characterized in that, The energy storage device (2) is a 12V lithium-ion storage device.

9. The prioritization method (100) according to any one of claims 1, 2, 4 and 5, characterized in that, The power generator (3) is a rotating motor or a system including at least one power storage device and a converter, the converter being constructed and configured to convert DC voltage into different DC voltages.

10. A vehicle (1) configured and equipped to implement the steps of a prioritization method (100) according to any one of claims 1 to 9 for prioritizing the electrical power supply of an on-board network relative to the recharging of a vehicle battery.

Images