MOTOR VEHICLE COMPRISING A MEANS FOR COMPENSATING CHARGING CURRENT BELOW AN OVERCHARGE THRESHOLD, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising a traction battery; an on-board charger for connecting the battery to a current source, and controlling a charging current demand; accessory components; and a correction system which comprises:- means for monitoring the instantaneous current of the battery (MBi);- means for evaluating an overload limit (SC);- means for evaluating a consumption of the accessory components (ACR, ACC);- compensation means activated if said instantaneous current (MBi) is greater than said overload limit (SC), the compensation means correcting the charging current demand by removing therefrom the consumption of the accessory components (ACR, ACC). The invention also relates to a method and a program based on such a vehicle. Figure 1

Description

Title of the invention: MOTOR VEHICLE COMPRISING A CHARGING CURRENT COMPENSATION MEANS BELOW AN OVERLOAD THRESHOLD, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of architectures of traction battery motors for motor vehicles, as well as to the charging controls of these batteries.

[0002] These architectures generally include an on-board charger connected to the traction battery, and connected or connectable to a current source to recharge the traction battery.

[0003] Unfortunately, it is common that due to uncertainties in measuring the consumption of accessory components of the high voltage circuit, the charging current requested from the charging source exceeds a specific threshold of the battery beyond which there is a risk of thermal runaway, interruptions in battery charging (in particular for accessory components controlled by pulse width modulation) and risks of battery discharge. Such overcurrents can cause battery contactors to open.

[0004] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution for protecting the battery against overcharges and avoiding overcurrents and thermal runaways, while ensuring the availability of the battery.

[0005] To achieve this objective, the invention provides a motor vehicle comprising a traction battery; an on-board charger connected to the battery, configured to connect the battery to a current source, and controlling a charging current demand from the source; accessory components powered by the traction battery; and a correction system which comprises: - a monitoring means monitoring an instantaneous current of the traction battery; - a means of assessing an overload limit of the traction battery; - a means of evaluating the consumption of accessory components; - a compensation means activated if the instantaneous current of the traction battery is greater than the overload limit of the traction battery, the compensation means correcting the charging current demand by removing the consumption of the accessory components.

[0006] In particular, the compensation means is deactivated if the instantaneous current of the traction battery is lower than the overload limit of the traction battery.

[0007] Advantageously, the invention proposes an intelligent charge management system for high voltage batteries in electric vehicles. It corrects in real time the current requested from the charging source in order to avoid any overcharging of the battery despite the inaccuracies of the electrical components.

[0008] In particular, thanks to a current monitoring and compensation algorithm calibrated according to the battery limit, the system guarantees that the instantaneous current will always remain within the tolerated limits. This makes it possible to effectively protect the battery while ensuring continuity of charging, even in the presence of uncertainties.

[0009] According to a variant, the compensation means corrects the charging current demand by further requesting a compensation current opposite to the charging current.

[0010] This allows the corrected requested current to be efficiently evaluated.

[0011] According to a variant, the compensation means implements the formula: ichrgn = ichLimHVB + hnstAux + ÎCompOÙ ichrgn: is the charging current requested from the source; ÎLimChHVB: is the limit charge current of the traction battery; hnstAux: is the instantaneous auxiliary current; and icomp: is the compensation current.

[0012] This allows the corrected requested current to be evaluated efficiently and accurately.

[0013] According to a variant, the system comprises a means of connection to the source which is a terminal in mode 4, a charger in mode 2 or in mode 3, or an electrical machine in the regeneration phase.

[0014] This allows different types of recharging to be taken into account.

[0015] The invention further relates to a method for correcting the load demand of a motor vehicle according to the invention, comprising the following steps: - a monitoring step in which an instantaneous current of the traction battery is monitored; - a step of evaluating an overload limit of the traction battery; - a step of evaluating the consumption of accessory components; - a compensation step carried out if the instantaneous current of the traction battery is greater than the overload limit of the traction battery, in which the charging current demand is corrected by removing the consumption of the accessory components.

[0016] In particular, the compensation step is not carried out if the instantaneous current of the traction battery is lower than the overload limit of the traction battery.

[0017] According to a variant, in the compensation step, the charging current demand is corrected by further requesting a compensation current opposite to the charging current. charge.

[0018] According to a variant, in the compensation step, the formula is implemented: ichLimHVB + iInstAux + ÎCompOÙ ictogn: is the recharge current requested from the source; ^LimChHVB: is the limit charge current of the traction battery; hnstAux: is the instantaneous auxiliary current; and icomp: is the compensation current.

[0019] According to a variant, the method comprises a step of connection to the source which is a terminal in mode 4, a charger in mode 2 or in mode 3, or an electrical machine in the regeneration phase.

[0020] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the load demand correction method according to the invention, when said program operates on a computer.

[0021] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended [Fig.l] illustrating an example of implementation of the invention.

[0022] The invention proposes a correction strategy to avoid overcharging of the traction battery (also called high voltage battery), by monitoring a current limit of the high voltage battery (at 0A for example when the battery is fully charged) as well as the instantaneous current of the battery.

[0023] The invention makes it possible to ensure that the difference between these two values is compensated and does not exceed the battery current limits due to uncertainties originating from the accessory consumers of the high-voltage circuit, and in particular the electrical components controlled by pulse width modulation. This makes it possible to avoid an overcurrent fault which can cause the contactors to open and / or thermal runaway.

[0024] In order to recharge a high voltage battery in electric or hybrid vehicles, recharges can be implemented: - using an external energy source: terminal in mode 2 or mode 3 (AC) or in mode 4; - in regeneration, produced during braking or deceleration of an electric vehicle, and converted into electrical energy to recharge the traction battery.

[0025] If the traction battery is fully charged, there is a risk of it being overcharged due to uncertainties from high-voltage consumers and electrical components controlled by pulse width modulation.

[0026] In this case, a function is developed to monitor the instantaneous current. of the traction battery so that it does not exceed the SC limit current of the traction battery. If this is the case, the current requested at the terminal and / or the charger and / or the electric machine is corrected.

[0027] In the step enabling correction to avoid overloads, the traction battery current limit and the instantaneous current are monitored, ensuring that the error between these two values is compensated and does not exceed the battery current limits due to uncertainties of high voltage consumers. In addition, a fixed limitation is added, applied when activating an electrical component controlled by pulse width modulation.

[0028] The strategy is composed of the following steps:

[0029] The following conditions must first be checked: - if the high voltage electrical system is activated, or - the charging process is an energy transfer and the maximum charging current of the on-board charger is greater than the maximum charging current of the high-voltage battery minus a calibration value; - and the maximum charging current of the high voltage battery is greater than the SC calibration threshold; - and the battery state of charge is above a state of charge threshold; - and no reconfiguration is enabled.

[0030] If the conditions are verified, then the correction strategy is activated; otherwise: a correction equal to 0A will be applied: icomp “ OA where icomp: is the compensation current.

[0031] The correction strategy is based on the following steps:

[0032] In a first step, the maximum auxiliary current ACR is calculated: ÎMaxAux = pMaxAux / u1IVB °ù PM®Aux ; is the maximum power consumed by the accessory (axillary) electrical components of the high-voltage circuit; and Uhvb is the instantaneous voltage of the traction battery.

[0033] This variable is used to determine the maximum compensation correction, based on this value as well as the instantaneous current of the accessory components.

[0034] Then, we calculate the high voltage current of the components driven by pulse width modulation: ÎMaxAuxPMW “ pm®auxpmw / ur where PMaxA«xPMW: is the maximum power consumed by the axillary components driven by pulse width modulation.

[0035] This variable takes into account high voltage consumers controlled by pulse width modulation. Thus, this current is part of the current maximum auxiliary.

[0036] Then, the instantaneous auxiliary current ACc is calculated: iinstAux- The reference ACc concerns the calculated value, and the reference ACR concerns the actual value.

[0037] Then, the minimum instantaneous current MBi of the high-voltage battery is calculated during a time window Ti; i^^. In particular, this is the instantaneous current of the battery taking into account the compensation in order to avoid exceeding the limit current under load. The time window Tl makes it possible to have a stable correction and to filter out the fluctuations / oscillations of the instantaneous current measured by the battery.

[0038] Then, we calculate the maximum charge limit of the current of the high voltage battery SC during a time window T7: i^nChHVB- Particularly, this is the maximum current that the battery can accept in recharging during the time window T2. Depending on the calibrations, T1 can be greater than, less than or equal to T2. The time window T2 refers to pulses (for example 2s, 10s, 30s, or continuous).

[0039] In a second step, we calculate the maximum compensation current: IMaxComp iMaxAux “ hnstAux-

[0040] Then, we calculate the compensation current of the maximum saturation threshold: / iMaxComp - iwaxPWM: when modulation-controlled components are enabled \ iMaxAux ~ mUX 0; . aa' ■ ' I \ IMaxComp: when deactivated /

[0041] Then, we calculate the error current: _ ;Min -Max lErr ~ WB ' timChHVB'

[0042] In a third step, integral regulation is used to eliminate static errors and ensure that the battery current limit is respected. Thus, the compensation current is calculated: ; — ; m civ / n- ; • Iâ' \ with: The coefficient of iComp — IMaxComp- niSX^ U, ÏHinI IMaxAux' J^i ^Err^'' / j regulator correction.

[0043] Thus, the current required for recharging is based on the following formula: ichrgn = ichLimHVB+ iinstAux + ÎCompOÙ ichrgn: is the recharge current requested from the source; ÎLimChHVB: is the limit charge current of the traction battery; iinstAux: is the instantaneous auxiliary current; and icomp: is the compensation current.

[0044] The MBC reference concerns the compensated current demand, which remains below the SC threshold.

[0045] The invention further relates to a program for implementing a method as described above. The program can be loaded into the memory of a controller of the motor vehicle, for example in a traction battery controller or an on-board charger controller.

Claims

Claims

1. A motor vehicle comprising a traction battery; an on-board charger connected to the battery, configured to connect the battery to a current source, and controlling a charging current demand from the source; accessory components powered by the traction battery; and a correction system which comprises: - monitoring means monitoring an instantaneous current of the traction battery (MB;); - means for evaluating an overcharge limit of the traction battery (SC); - means for evaluating a consumption of the accessory components (ACr, ACc); - compensation means activated if the instantaneous current of the traction battery (MB;) is greater than the overcharge limit of the traction battery (SC), the compensation means correcting the charging current demand by removing the consumption of the accessory components (ACr, ACc) therefrom.

2. Motor vehicle according to claim 1, characterized in that the compensation means corrects the charging current demand by further requesting a compensation current (Cp) opposite to the charging current.

3. Motor vehicle according to any one of claims 1 to 2, characterized in that the compensation means implements the formula: ÎChrgn ~ ^ChLimHVB 4nstAux ^Comp°Ù ^Chign: is the recharge current requested from the source; ÎLimChHVB: is the limit charge current of the traction battery; hnstAux: is the instantaneous auxiliary current; and icomp: is the compensation current.

4. Motor vehicle according to any one of claims 1 to 3, characterized in that it comprises a means of connection to the source which is a terminal in mode 4, a charger in mode 2 or in mode 3, or an electrical machine in the regeneration phase.

5. A method for correcting the charge demand of a motor vehicle according to any one of claims 1 to 4, comprising the following steps: - a monitoring step in which a current is monitored instantaneous current of the traction battery (MB;); - a step of evaluating an overload limit of the traction battery (SC); - a step of evaluating a consumption of the accessory components (ACR, ACc); - a compensation step carried out if the instantaneous current of the traction battery (MB;) is greater than the overload limit of the traction battery (SC), in which the charging current demand is corrected by removing the consumption of the accessory components (ACR, ACc).

6. Correction method according to claim 5, characterized in that in the compensation step, the charging current demand is corrected by further requesting a compensation current (Cp) opposite to the charging current.

7. Correction method according to any one of claims 5 to 6, characterized in that in the compensation step, the formula is implemented: ÎChrgn — îchLimHVB hnstAux ÎComp°Ù ÎChrgn • is the recharge current requested from the source; ÎLimChHVB: is the limit charge current of the traction battery; iinstAux: is the instantaneous auxiliary current; and icomp: is the compensation current.

8. Correction method according to any one of claims 5 to 7, characterized in that it comprises a step of connection to the source which is a terminal in mode 4, a charger in mode 2 or in mode 3, or an electrical machine in the regeneration phase.

9. A computer program comprising program code instructions for performing the steps of the load demand correction method according to any one of claims 5 to 8, when said program is running on a computer.

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