MOTOR VEHICLE COMPRISING A POWER ALLOCATION MEANS COMPENSATING FOR POWER LOST IN THE CABLES, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising:- electric traction machines;- an electrical component;- a traction battery supplying said electric machine and said electrical component;- a circuit comprising cables;- means for evaluating the electrical resistance of the cables (7), the voltage of the battery and said electrical component;- a calculation means calculating a lost power (10a) from these data;- a power allocation means (11) allocating a power to said electric machine and said electrical component, the allocation means (11) further allocates a compensation power to compensate for the lost power (10a). The invention also relates to a method and a program based on such a vehicle. Figure 3

Description

Title of the invention: MOTOR VEHICLE COMPRISING A POWER ALLOCATION MEANS COMPENSATING FOR POWER LOST IN THE CABLES, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of power control systems and methods in electric vehicle circuits.

[0002] In this field, when using these vehicles, the power from the batteries is distributed to an electrical machine in a high voltage circuit, and to at least one electrical component in a low voltage network.

[0003] In practice, the circuit cables actually have a resistance. This resistance is not taken into account in the power allocation modules supplying power to the electrical machine and said electronic component.

[0004] Thus, voltage drops in the electrical cables of the high-voltage network lead to dangers linked to undervoltage or overcurrent, which implies risks of opening the contactors of the high-voltage battery, and an interruption of the high-voltage electrical network.

[0005] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution for limiting the risks of opening the high-voltage battery contactors, as well as the risks of interruption of the high-voltage electrical network.

[0006] To achieve this objective, the invention proposes a motor vehicle comprising: - at least one electric traction machine; - at least one electrical component; - a traction battery powering said electric machine and said electrical component; - a circuit comprising cables connecting the traction battery to said electric machine and to said electrical component; - a means of evaluating the electrical resistance of cables; - a means of evaluating the voltage of the traction battery; - a means for evaluating the voltage of said electrical component; - a calculation means calculating a lost power from the electrical resistance of the cables, the voltage of the traction battery, the voltage of said electrical component; - a power allocation means allocating power to said electrical machine and to said electrical component, the allocation means further allocating a compensation power to compensate for lost power.

[0007] Advantageously, the invention makes it possible to compensate for the power lost in the cables, and thus to limit the risks of opening the battery contactors and interruption of the electrical network.

[0008] Preferably, the calculating means calculates the lost power using a least squares method.

[0009] This makes it possible to precisely determine the lost power and to improve the effectiveness of the compensation.

[0010] Preferably, the motor vehicle further comprises a control means controlling the contactors, the voltage and the current of said electrical machine, and it further comprises a trigger connected to said control means, activating the calculation module if the voltage and the current are available and valid, if the current of the electrical machine is greater than a predetermined threshold, and / or if the contactors are closed.

[0011] This makes it possible to determine the power lost when necessary, and to limit calculation times.

[0012] Preferably, the motor vehicle has a front-rear axis, and comprises a traction mechanism at the front and a propulsion mechanism at the rear with reference to the front-rear axis, characterized in that it comprises a first electric machine coupled to the traction mechanism, and a second electric machine coupled to the propulsion mechanism.

[0013] This makes it possible to adapt the invention to vehicles having two electric machines on traction and propulsion mechanisms.

[0014] Preferably, the allocation means comprises a priority module implementing a decreasing priority scale giving priority to said electrical component, then to the cables, then to said electrical machine.

[0015] This allows power to be allocated as a priority to the electrical components and then to the cables.

[0016] The invention further relates to a method for controlling power in a motor vehicle according to the invention, characterized in that it comprises the following steps: - a step of evaluating the electrical resistance of the cables; - a step of evaluating the voltage of the traction battery; - a step of evaluating the voltage of said electrical component; - a calculation step in which the power lost is calculated from the electrical resistance of the cables, the voltage of the traction battery, the voltage of said electrical component; - a power allocation step in which power is allocated to said electrical machine and said electrical component, a compensation power is also allocated to compensate for the lost power

[0017] Preferably, in the calculation step, the lost power is calculated using a least squares method.

[0018] Preferably, the power control method further comprises a current control step in which the current of said electrical machine is controlled, characterized in that it further comprises a triggering step in which the calculation step is activated if the current of the electrical machine is greater than a predetermined threshold.

[0019] Preferably, in the allocation step, a decreasing priority scale is implemented giving priority to said electrical component, then to the cables, then to said electrical machine.

[0020] Another object of the invention relates to a computer program comprising program code instructions for executing the steps of the power control 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 figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a motor vehicle suitable for implementing the invention; - [Fig.2] schematically illustrates the operation of the calculation means of a vehicle according to a preferred variant of the invention; - [Fig.3] schematically illustrates the operation of the calculation means and a means of allocating power of a vehicle according to the preferred variant.

[0022] The invention relates to a motor vehicle which comprises two electrical machines M1, M2 on two traction mechanisms at the front, and propulsion at the rear; and at least one electrical component in particular in a low voltage circuit with a DCDC converter and low voltage consumers.

[0023] The vehicle further comprises a traction battery B powering said electric machine M1, M2 and said DC electrical component; and a circuit comprising cables C1 connecting the traction battery B to said electric machine M1, M2 and said electrical component.

[0024] The invention proposes a solution for compensating for voltage drops in the electrical cables Cl of the 48V network to prevent dangers linked to undervoltage or overcurrent, resulting from the omission of the resistance of the electrical cables CL. The objective is to prevent any risk of opening the contactors of the 48V battery, thus avoiding an interruption of the 48V electrical network.

[0025] The electrical resistance of these cables Cl is evaluated by the least squares method, based on the voltage of the 48V battery and the voltage of the electrical components, and mainly of the front machine Ml and rear M2 in the electric vehicle.

[0026] These resistances can then be used to calculate the power lost in the cables C1, which can be subtracted from the maximum power allocated to traction (lost power). The objective is to avoid any risk of opening the 48V battery contactors, thus preventing any interruption of the 48V electrical network.

[0027] In order to avoid interruption of the 48V electrical network following an overcurrent or undervoltage fault in the 48V battery, the losses in the electrical cables of the 48V network will be compensated by following the following steps: - estimation of the resistance of an electric cable at 48V; - estimation of loss in 48V electrical cables; - calculation of traction power allocation taking into account cable losses.

[0028] For the estimation of the resistance in an electric cable Cl, the recursive least squares method will be used, following the procedure illustrated in [Fig.2].

[0029] Reference box 1 receives the voltage measurements of the battery VHVB(k), and of the electric machine VMEL(k) - The equation of box 1 is as follows: - ^hvb: the voltage measurement of the 48V battery; - Vmel: the voltage measurement of the electrical machine; - VIn; the voltage in the cable between the 48 V battery and the electrical machine (voltage drop), identified by the reference la in [Fig.2]; - : a discrete time index.

[0030] Reference box 2 receives the measurement of the current of the electric machine IMEE(k)-The equation of box 2 is as follows: O(£) = IMEL(k^ec - Imel: measurement of the current of the electric machine; - <3Xk): a regression matrix used to relate voltage and current observations to a given resistance, identified by reference 2a in [Fig.2].

[0031] Reference box 3 concerns the following equation: - e: an error between the measured voltage (V^) and the estimated voltage, identified by reference 3a in [Fig.2]; - 6(k): the parameter to be estimated (resistance of the electric cable) identified by reference 7 in figures 2 and 3; - T ; a matrix transpose.

[0032] Reference box 4 concerns the following equation: K(k) = P[k-lj<3)(£)[X + O( / c) r P^ - K(k): a gain matrix, identified by reference 4a; - P(k): a covariance matrix; - A; a forgetting factor, it is a parameter that controls the speed of forgetting past information when updating its predictions or parameters.

[0033] Reference box 5 concerns the following equation: P(k) = ±(lK(k)®(^ 1)

[0034] This results in the reference value 5a identifying P(k -1).

[0035] Reference box 4 concerns the following equation: Q(k) = e(k-1)+K(k^

[0036] This results in the reference value 7 identifying 0(k).

[0037] The reference DA concerns an activation trigger (or “Activation Trigger” in English) for each electrical machine M1, M2. This is a condition of the estimation which is true when: - the 48V battery voltage and machine voltage information and machine current are available and valid; and - the current of the electrical machine Ml or M2 is greater than a calibrable threshold; and - the 48V battery contactors are closed.

[0038] For the estimation of the losses of the 48V electric cables (between the front machine M1 and the 48V battery B; and between the rear machine M2 and the 48V battery), [Fig.3] is applicable. The diagram on the left and above is similar to that of [Fig.2], applied to the front machine M1; the one below being applied to the rear machine M2. The DA triggers are specific to each machine.

[0039] The cable resistance Q(k) (reference 7) determined previously is at the input of step 10 for each machine. The corresponding equation is as follows: p _ ( nHVB-FEM -2 \ , ( pHVB-REM-2 \ with ^LossWire — [^Wire -lFEM ) + X^Wire -lREM ) - Ifem: the measurement of the current of the electric machine before Ml, represented by the reference 8 in [Fig.3]; -Irem: the measurement of the current of the rear electric machine M2, represented by the reference 9 in [Fig.3]; - estimated resistance in the cable between the 48V battery and the machine AXWire before Ml; - estimated resistance in the cable between the 48V battery and the machine AVWire rear M2; - PLossWire ■ loss at the level of the electrical cables on the 48V side mainly between the electric machines and the 48V battery, represented by the reference 10a; 'ipEM: measurement of the current of the electric machine before Ml in motor mode; - ^rem: measurement of the current of the rear electric machine M2 in motor mode.

[0040] i2FEM is located in: I FEM ; when the electric machine in motor mode 0; when the electric machine in generator mode ; And i^ EM est é sal to: Ir^; when the electric machine in motor mode 0 ; when the electric machine in generator mode

[0041]

[0042]

[0043]

[0044] The calculation of the traction power allocation is made taking into account the losses of the cables Cl. The calculation of the power vector with a peak, nominal and stabilized depends on: - the power available in high-voltage networks; - a power limitation vector; - priority index vectors; - instantaneous power vectors of consumers; - a calibration to define the maximum power of electrical consumers; and - the condition of the electrical system. The power available in the networks (P^se) is equal to the maximum power that the battery can provide (peak, nominal, stabilized), in addition to the power of the electric machine in generator mode. The power limitation vector (denoted PLim = [PEim . P^J) depends on activation, deactivation and power limit information for high voltage consumers. It consists of two main functions: - power limitation of high-voltage electrical consumers: it is calculated on the basis of the maximum potential that the DCDC converter can supply in the high-voltage or low-voltage network; or on the basis of a map dependent on the state of charge (SOC) and the battery temperature in the nominal case; or only on the battery temperature in the event of a failure of the thermal system (battery cooling); - the power limitation vector of electrical consumers can be based on the authorization of activation of electrical consumers based on a “48V electrical system request” and / or “the internal mission of the HV electrical system” in plugged-in mode (“Plugln”) or not. The priority index vector is based on several flows such as the “Request from the 48V electrical system" and / or "the needs of 48V electrical consumers".

[0045] In a first step, we calculate the power allocated to the highest priority electrical consumer P^^f idxJ with the equation: PM**,] =max(ftmin(PSfi PU PLx)) avecp U- la P uissance maximum of high voltage electrical consumers.

[0046] The priority index vectors allow to determine the component with the highest priority order index (the first index being idxd

[0047] Using this index, we can determine the power limit of this electrical consumer (p^. )) and the maximum power of the high voltage consumer (p* )). Max77

[0048] In the next step, we calculate the allocated power according to the following equation: PAfcbdxj] = max(ftnrinfp^-PSJ*^ Pf» pU))wherepS&L-»» is the sum of the powers of the HV electrical consumers having a higher priority than that of the 48V electrical consumer.

[0049] Similarly for the second electric motor, the priority index vectors make it possible to know the component with the priority order index j (the index idxj).

[0050] Using this index, we can determine the power limit of this electrical consumer (pi \ and the maximum power of the 48V (pi ). T Lim / 1 Max

[0051] The pMse power depends on the state of the 48V electrical system demand »UmEKonHiPrio and power allocation vectors and instantaneous power vectors.

[0052] In the case of front and rear dual-wheel drive vehicles such as that of [Fig. 1], there are the following electrical components: - 12V electrical system: with DCDC converter; - Traction system (traction device, front engine rear engine).

[0053] Power allocations are calculated in the following order of priority: - Highest priority: 12V system: DCDC; - 2nd priority: Loss of high voltage electrical cables (Ml / 48V battery, M2 / 48V battery); - 3rd priority order: Traction system (T).

[0054] This is achieved with the power allocated to the DCDC equal to: pPulse _mav (H- pDCDC. pDCDC\ )with ^AiiocDCDC-m^x(U, min( PAvS, PLim, PMax JJ with - Purræ the Limit Power of the DCDC converter on the high voltage side following a derating linked for example to its temperature or its voltage or to a fault; and - PMa?C the maximum power on the high voltage side that the DCDC converter is able to provide.

[0055] The allocated power cable losses are equal to: <r“) )*« = pPulse _ pPulse pPulse _ pPulse pPulse AvlLossWiœ ~ *Avl " SuniEiornHiPi-io — *Avl ” AllocDCDC

[0056] The power allocated to traction is equal to: PSl£ T „ = max(^^^ PÏS pPulse _ pPulse _ pPulse C( pPulse _ pPulse _ pPulse _ pPulse *AvlTrac — a Avl ^SumE!ConHiPrio ^AvlTrac — *Avl * Allocæ!^ ^AllocLœ;,Wjre

[0057] The power allocated to traction is then used to calculate the electrical power allocations: to the traction system T, and to the electrical machines, and then, on the basis of this power, we can construct the torque instructions sent to these machines M1, M2.

[0058] The invention makes it possible to improve the robustness of control and of the system by taking into account losses in the electrical cables in order to avoid opening of the 48V contactors following overcurrent and undervoltage faults. Furthermore, the invention makes it possible to minimize CO2 emissions by increasing the autonomy of the 48V battery.

Claims

Claims

1. Motor vehicle comprising: - at least one electric traction machine (Ml, M2); - at least one electrical component (DC); - a traction battery (B) powering said electric machine (Ml, M2) and said electrical component (DC); - a circuit comprising cables (Cl) connecting the traction battery (B) to said electric machine (Ml, M2) and to said electrical component (DC); - means for evaluating the electrical resistance of the cables (7); - means for evaluating the voltage of the traction battery; - means for evaluating the voltage of said electrical component; - calculating means calculating a lost power (10a) from the electrical resistance of the cables (7), the voltage of the traction battery, the voltage of said electrical component;- a power allocation means (11) allocating power to said electrical machine and said electrical component, the allocation means (11) further allocating compensation power to compensate for the lost power (10a).;

2. Motor vehicle according to claim 1, characterized in that the calculating means calculates the lost power (10a) by means of a least squares method.

3. Motor vehicle according to any one of claims 1 to 2, further comprising a control means controlling the contactors, the voltage and the current of said electrical machine, characterized in that it further comprises a trigger (DA) connected to said control means, activating the calculation module if the voltage and the current are available and valid, if the current of the electrical machine is greater than a predetermined threshold, and / or if the contactors are closed.

4. Motor vehicle according to any one of claims 1 to 3, having a front-rear axis (X), and comprising a traction mechanism at the front and a propulsion mechanism at the rear with reference to the front-rear axis (X), characterized in that it comprises a first electric machine (M1) coupled to the traction mechanism, and a second electric machine (M2) coupled to the propulsion mechanism.

5. Motor vehicle according to any one of claims 1 to 4, characterized in that the allocation means (11) comprises a priority module implementing a decreasing priority scale giving priority to said electrical component, then to the cables, then to said electrical machine.

6. Method for controlling power in a motor vehicle according to any one of claims 1 to 5, characterized in that it comprises the following steps: - a step of evaluating the electrical resistance of the cables; - a step of evaluating the voltage of the traction battery; - a step of evaluating the voltage of said electrical component; - a calculation step in which the lost power (10a) is calculated from the electrical resistance of the cables, the voltage of the traction battery, the voltage of said electrical component; - a power allocation step in which a power is allocated to said electrical machine and to said electrical component, a compensation power is further allocated to compensate for the lost power (10a).

7. Power control method according to claim 6, characterized in that in the calculation step, the lost power (10a) is calculated by means of a least squares method.

8. Power control method according to any one of claims 6 to 7, further comprising a current control step in which the current of said electrical machine is controlled, characterized in that it further comprises a triggering step in which the calculation step is activated if the current of the electrical machine is greater than a predetermined threshold.

9. Power control method according to any one of claims 6 to 8, characterized in that in the allocation step, a decreasing priority scale is implemented giving priority to said electrical component, then to the cables, then to said electrical machine.

10. A computer program comprising program code instructions for performing the steps of the power control method according to any one of claims 6 to 9, when said program is running on a computer.

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