FR2964509A1 - METHOD FOR CHARGING A POWER BATTERY OF A DRIVE MOTOR OF A MOTOR VEHICLE - Google Patents

Abstract

The method involves implementing a proportional integral type closed loop control phase by generating a control signal for controlling intensity of charging current of a power supply battery (1), where set point of the charging current intensity depends on a maximum electric power supplied by a battery charger (2) and/or a maximum electric power received by the battery. The intensity of charging current of the battery is measured, and difference between the measured intensity and the intensity set point is utilized during the control phase. Independent claims are also included for the following: (1) a computer readable recording medium comprising a set of instructions for implementing a power supply battery charging method (2) a computer module comprising hardware and/or software units to implement the power supply battery charging method (3) a power supply battery charging device comprising a computer module.

Description

The invention relates to a method for charging a battery for powering a drive motor of a motor vehicle. It also relates to a calculator of a motor vehicle governing such a method. It further comprises a charging device comprising such a calculator.

Some motor vehicles, such as electric or hybrid vehicles, include a battery for powering an electric drive motor of the vehicle, including a high-voltage battery. Different components intervene in the charge of the battery of an electric vehicle. We find: - the battery and its computer, - the battery charger and its calculator, - the vehicle supervision computer.

These three computers exchange information that allows the charging of the battery. Thus, from a number of information from the charger and the battery, the supervision computer can calculate a current setpoint that is sent to the charger. Then, the latter supplies the battery with a current according to the instruction and necessary to charge it.

However, the battery is not the only consumer of this current. Other consumers of "accessories" type (radio, headlight, heating, air conditioning ...) can be active during the charging of the battery. But these consumers should not limit the performance of the battery charge.

Moreover, at the end of charging, it is necessary to protect the battery against overvoltages. For this, it is important to be able to rapidly decrease the current setpoint sent to the charger by following the power instruction sent by the computer of the battery. MS \ REN232EN.doc.doc EP-265879, US20080084182, US20090295332, WO200904284 and EP2115852 disclose various battery charging devices and methods. In particular, the document WO200904284 describes a method of charging the battery in which the internal resistance of the battery is used.

The document EP2115852 describes a method of charging a battery in three phases: a first phase where the battery is charged with a low current, a second phase where the battery is charged with a constant current and a third phase where the battery is charged at constant voltage. Complex means, including several correctors, are necessary for the implementation of such a charging method. In addition, none of the documents cited above describes a solution that makes it possible to respond to the constraints mentioned above.

The object of the invention is to provide a battery charging method 20 improving the charging methods known from the prior art. In particular, the invention provides a charging method for rejecting the load disturbances due to consumers and in particular the power consumption variations thereof, to control the dynamics of the charger to protect the battery and ensure the stability of the charge of the battery.

The method according to the invention governs the charging of a supply battery of a drive motor of a motor vehicle. It is characterized in that a closed loop control phase of the intensity of the charging current of the battery is carried out, the charge current intensity setpoint being dependent on the maximum electric power that can be used. .dpt.doc5 provided by the charger and / or dependent on the maximum electrical power that can be received by the battery.

The regulation phase may comprise a step of generating a control signal of the intensity of the charging current, this control signal driving a charger generating a charging current of the battery. The intensity of the charging current of the battery can be measured and the difference between this measured current of the charging current of the battery and the charging current intensity of the battery can be used in the control phase.

The regulation phase may be of the proportional-integral type. The load current intensity reference can be determined by the following formula: I_Setpoint = min (P_ChargeAvailable_bcb_est, P_ChargeMax_bhv_est) 20 with: I_Setpoint: the load current intensity reference, P_ChargeAvailable_bcb_est: the maximum electrical power that can be supplied by the charger, P_ChargeMax_bhv_est: the maximum electrical power that can be received in the battery, Volt_HVNet_Triangulation_mes: the electrical voltage of the network powered by the battery. The regulation phase can be activated when the charge level of the battery is below a predefined threshold. MS \ REN232EN.doc.doc.doc Volt HVNet Triangulation mes A maximum electrical power information that can be supplied by the charger can be transmitted by the charger and / or a maximum electrical power information that can be received by the battery can be emitted by the battery . The regulation phase may comprise a step of saturation of the control of the intensity of the charging current of the battery.

The invention also relates to a data recording medium readable by a computer on which is recorded a computer program comprising software means for implementing the steps of the method defined above.

The invention also relates to a computer comprising hardware and / or software means for implementing the charging method defined above, in particular implementing the regulation phase of the previously defined method. The hardware and / or software means may comprise a load current intensity reference generator and a regulator. The hardware and / or software means may comprise a subtractor calculating the difference between the charging current intensity setpoint and a measurement of the charging current intensity. The invention also relates to a device for charging a battery for powering a drive motor of a motor vehicle. It includes a calculator previously defined and a charger. According to the invention, the motor vehicle comprises a previously defined computer or a charging device defined above. The accompanying drawings show, by way of example, an embodiment of the charging method according to the invention and an embodiment of a charging device according to the invention.

Figure 1 is a diagram of an installation comprising a charging device for charging a battery according to the invention.

Figure 2 is a diagram showing an embodiment of a supervision computer of a motor vehicle governing the charging method according to the invention.

FIG. 3 is a detailed electronic diagram of the embodiment of the supervision computer.

FIG. 4 is a detailed diagram of a first block of the supervision computer embodiment.

Figure 5 is a detail diagram of a second block of the supervisory computer embodiment. Figure 6 is a diagram similar to that of Figure 1, various functions of the supervision computer being shown in detail.

Figure 7 is a diagram of an installation for charging a battery according to the invention.

Figures 8 and 9 are gain and phase Bode diagrams of the charger.

Figure 10 is an abacus for determining a damping coefficient. Figure 11 is a diagram showing the response of the charger to a voltage step.

FIG. 12 is a diagram of an embodiment of a corrector used to implement the method according to the invention.

Figure 13 is a Bode diagram of the charging device according to the invention in open loop and closed loop. The invention relates to a method of charging a battery. This method comprises in particular a regulation step for regulating the charge of the battery.

One embodiment of a device 8 for charging a battery according to the method of the invention is shown in FIGS. 1 and 6. The charging device 8 comprises in particular: a battery charger 2 and its computer, a supervision computer 3 of the vehicle. The computers of the battery to be charged, the charger and the supervision exchange information which makes it possible to charge the battery. Thus, from a number of information from the charger and the battery, the supervision computer can calculate a current setpoint that is sent to the charger. The supervision computer also uses battery charging current information. To this end, the charging device 8 also comprises a sensor 9 for measuring the charging current of the battery. At the output, the charger supplies the battery with a current according to the instruction and necessary to charge it. Preferably, the supervision computer is an on-board computer of the vehicle. Preferably, also, the charger is embedded on the vehicle.

The battery is not the only consumer of this current. Other consumers 4 type "accessories" (radio, headlight, heating, air conditioning ...) can be active during the charging of the battery. But these consumers should not limit the performance of the battery charge. The supervision computer and the charging method that it governs make it possible to optimize the performance of the load and to protect the battery, especially during variations in the consumers' power consumption.

To do this, as shown in FIG. 6, the supervision computer preferably comprises a generator 69 of current setpoint and a regulator 70 or corrector. The regulator is preferably a PI (proportional-integral) type regulator.

An embodiment of a supervision computer according to the invention is described below by way of example. The supervision computer 3 shows the inputs and outputs listed in the following table: Inputs Outputs B_Failure_Charger: Logic signal I_OutChargeSet_bcb: Setpoint indicating whether a fault in the load current (in A). charger has been detected If B_Failure_Chargeur = 1, a fault is present at the charger. If B_Failure_Chargeur = 0, the charger has no fault. MS \ REN232EN.dp.doc20 This signal is generated by the charger computer. B_Failure_Batterie: Logic signal indicating if a fault in the battery has been detected If B_Failure_Batterie = 1, a fault is present on the battery. If B_Failure_Batterie = 0, the battery has no fault. This signal is elaborated by the computer of the battery. Pct_UserSOC_bhv_est: Signal indicating the state of charge of the battery in%. This signal is calculated by the computer of the battery. B_EndOfCharge_bhv_req: Logic signal indicating whether the load is finished. B_EndOfCharge_bhv_req = 1 - the load is finished. 0 - the B_EndOfCharge_bhv_req = load is not finished. This signal is calculated by the computer of the battery. I_bhv mes: Signal indicating the current measured at the input of the battery at A. This signal comes from a sensor. This signal can be transmitted by the computer of the battery. Volt_HVNet_Triangulation_mes: Signal indicating the V voltage of the MS \ REN232FR.dt.doc network powered by the battery. This signal comes from a sensor. This signal can be transmitted by the computer of the battery. P_ChargeMax_bhv_est: Signal indicating the maximum load power that the battery can receive in kW. This signal is calculated by the battery calculator. P_ChargeAvailable_bcb_est: Signal indicating the maximum load power the charger can provide in kW. This signal is calculated by the charger computer. In the embodiment described, the supervision computer comprises a first block 5 and a second block 6 shown in FIG.

The first block 5 of the supervision computer 3 has the inputs and outputs listed in the following table: Inputs Outputs B_Failure_Charger B_ActivationCurrentRegulation: Logic signal for activating a regulation loop of the charging current of the battery. B_ActivationCurrentRegulation = 1 - the current regulation is activated. B_ActivationCurrentRegulation = 0 - the current control is deactivated. MS \ REN232EN.doc.doc B Failure Battery Pct_UserSOC_bhv_est B_EndOfCharge_bhv_req The current regulation is activated under certain conditions. The conditions for activating the regulation of the charge of the battery are the following: - No fault in the charger (short circuit, state of the lock, presence of the network ...) that is to say B_Failure_Chargeur = O, - No fault on the battery (sensors, overvoltage / overvoltage ...) ie B_Failure_Batterie = O, - The state of charge of the battery must be lower than a certain percentage C_UserSOCLim_SC (do not overload the battery) ie Pct_UserSOC_bhv_is <C_UserSOCLim_SC, - the load must not be terminated, that is B_EndOfCharge_bhv_req must be equal to O.

When all these conditions are met, you can activate the regulation of the battery charge. To do this, a logic signal B_ActivationCurrentRegulation goes high. This logic can be implemented, as shown in FIG. 4, by means of comparators 51 to 54 and an AND logic gate 55.

The second block 6 of the supervision computer 3 has the inputs and outputs listed in the following table: it is noted that the output of the first block 5 constitutes an input of the second block 6. Inputs Outputs B_ActivationCurrentRegulation: Signal I_OutChargeSet_bcb: Setpoint MS \ REN232FR.dpt .doc25 logic to activate the load current loop in A. It is regulation. the computer output of B_ActivationCurrentRegulation = 1 - supervision 3. the current regulation is activated. B_ActivationCurrentRegulation = 0 - the current control is deactivated. I bhv mes: Volt_HVNet_Triangulation_mes: P_ChargeMax_bhv_est: P_ChargeAvai Iable_bcb_est: The parameters used in this block are as follows: Parameters Definition Kp Proportional gain of a corrector Ki Integral gain of a corrector Kp Term translating the frequency of Ti = interruption of the action integral. Ki Ts Sampling period of the system FIG. 5 represents an exemplary embodiment making it possible to implement the logic described hereinafter.

As we have seen previously, the regulation of the charging current of the battery is activated when the signal B_ActivationCurrentRegulation is in the high state (B_ActivationCurrentRegulation = 1). This activation is done through the "enable" block 7. When the B_ActivationCurrentRegulation signal is high, the output of the Regulation_Charge_Battery block is determined by the signal I_OutChargeSet_bcb calculated in the second block. MS \ REN232EN.doc.doc When the B_ActivationCurrentRegulation signal is low, the output of the Regulation_Charge_Battery block is equal to zero. V olt_HVNet_Triangulation_mes This current setpoint is thus calculated from the maximum power that the charger can provide, the maximum power that can receive the battery (which is in particular a function of the state of charge of the battery and its temperature. ..) and the voltage of the high voltage network. For example, as shown in FIG. 5, this calculation can be performed by a first sub-block 69 comprising a logic gate 61 having at its output a signal whose value is equal to the value of the signal of lower intensity attacking its inputs. and having a division logic gate 62. The current setpoint signal I_Setpoint is output from this sub-block 69.

This current setpoint I_Setpoint is then compared to the current measured at the input of the battery I_bhv_mes. One derives, for example thanks to a subtraction operator, an error: Error = I_Setpoint - I_bhv mes.

If electrical consumers of the vehicle are active, the current measured at the input of the battery will decrease. To avoid this, it is necessary to set up a current regulation loop. This loop makes it possible to reject the disturbances that consumers represent and to respect the response time required to protect the battery in the event of an overvoltage while guaranteeing good stability margins. This regulation can for example be carried out by means of a corrector 70. A current setpoint I_Setpoint is calculated in the second block 5 according to the formula: Setpoint = min (P_ChargeAvailable_bcb_est, P_ChargeMax_bhv_est) I_ comprising a second subset block 68, a logic gate 66 and an amplifier 65.

To set the regulation, it is necessary to know the transfer function between the setpoint current I_cons_EVC given by the vehicle supervision computer and the input current of the battery I_bhv_mes as shown in Figure 7. In the following, we The term "system" refers to the loader represented by this transfer function.

For this purpose, it is possible to carry out a frequency identification on a vehicle: - Thanks to the Bode diagram of the gain shown in FIG. 8, it is possible to determine the gain of the transfer function of the charger: K (in dB). - The cutoff frequency of the system can be read using the two diagrams of Figures 9 and 10. Using the Bode diagram of the phase (Figure 9): at 90 ° phase, we look at how often we are. We can then read the frequency w0. - Then thanks to the chart in Figure 10, we find a damping coefficient

We then identify a 2nd order transfer function whose three coefficients K (in dB), w0, its identified: The parameters of the corrector can then be calculated. Choice of the parameters of the corrector: MS \ REN232EN.dpt.doc K 1 * p2 + 2 * p + 1 a) 02 (110 FTBCB = 25 Let us first look at the answer index (response to a step) of the open-loop system (shown in figure 11) A static error and a response time of about 3 s are observed This response time does not meet the protection requirements of the high voltage battery However, the corrector will allow to accelerate the system and to answer the constraints of protection of the battery C (s) = Kp + Ki - We synthesize a corrector of type PI of the form s with anti-wind-up With s which is the variable of Laplace.

FIG. 12 shows the generic structure of this type of corrector which has the advantage of naturally integrating an anti Wind Up device. This device is an anti-saturation device that allows to take into account the saturations in the generation of the command (the integral action is calculated from the saturated command).

Proportional action adjustment Let's look at Figure 13, the Bode diagram of the system's open-loop transfer function. To guarantee robustness, it is desirable for the corrector to guarantee a phase margin of at least 45 °. Let's look at what is the maximum proportional gain that we can put while respecting this criterion. To do this, simply read the gain at the frequency where the phase is 135 ° and take a slightly lower value. We thus obtain the gain Kp of the corrector.

Adjustment of integral action The frequency of the integral action (fi in Hz) is chosen at a frequency equal to one decade below the frequency where the phase is 135 ° in open loop. Indeed the purpose of the integral action is to cancel the static error.

Its action is therefore important for low frequencies. The goal is MS \ REN232FR.dt.doc to gain low frequencies. On the other hand an integral action causes a phase shift of 90 °, which can degrade the margins of stability. Thus, around the frequencies that interest us, it is desired that the phase shift induced by the corrector is zero. We get the gain Ki of the corrector.

Realization of the corrector As mentioned above, a possible embodiment of the corrector 70 is given in FIG.

The command is saturated between the minimum value 0 and the maximum value P_ChargeAvailable_bcb_est which is obtained at the output of the gate 63 and is the maximum power that the charger can provide. The saturation is obtained thanks to the gate 67. The sub-block 68 is a discretized embodiment of the integral action with anti-wind-up (discretization of the formula 1 + 1sTi shown in FIG. 12).

Figure 13 shows the open loop and closed loop responses of the system. As we can see thanks to the corrector set up, the response of the system is accelerated and its improved precision (zero gain at low frequencies) while guaranteeing a phase margin greater than 45 °. The adjustments of the corrector can be fine-tuned for fine tuning on the vehicle in the debugging phase.

Ending a Charge If a fault from the charger or battery appears during charging. The control is deactivated and the load stops. At the end of charging, the battery sends an end of charge signal to stop charging B_EndOfCharge_bhv_req. Indeed, thanks to the state of charge information of the battery Pct_UserSOC_bhv_est, when the battery reaches a high charge level, it stops the load.

The method and the computer according to the invention have advantages over the charging methods and devices known from the state of the art: the corrector used is simple, it is preferably of the type PI; 10 - The closed-loop structure makes it possible to reject the disturbances of the system; - The management of the saturations of the control is taken into account at the level of the control of current by well controlled means (anti-wind-up) 15 We can add the following advantages: - The control structure in closed loop is simple and robust to the uncertainties of the system. - Nominal setting parameters guarantee good stability margins to the system. The Proportional Integral type corrector is inexpensive in computation time and well controlled. The invention applies to all types of charger and / or battery technologies.

MS \ REN232EN.doc.doc

Claims (14)

1. A method of charging a battery (1) for supplying a drive motor of a motor vehicle, characterized in that a closed-loop control phase of the intensity of the current is carried out. charging the battery, the charge current intensity setpoint being dependent on the maximum electric power that can be provided by the charger and / or dependent on the maximum electrical power that can be received by the battery. 2. Charging method according to the preceding claim, characterized in that the regulation phase comprises a step of generating a control signal of the intensity of the charging current, this control signal driving a charger (2) generating a charging current of the battery. 3. Charging method according to the preceding claim, characterized in that the intensity of the charging current of the battery is measured and in that the difference between this measured intensity of the charging current of the battery and the current intensity of the Battery charging current is used in the regulation phase. 4. Charging method according to one of the preceding claims, characterized in that the regulation phase is of the proportional-integral type. 5. Charging method according to one of the preceding claims, characterized in that the load current intensity setpoint is determined by the following formula: I_Setpoint = min (P_ChargeAvailable_bcb_est, P_ChargeMax_bhv_est) V olt_HVNet_Triangulation_mes MS \ REN232EN.dt.doc 1730with: I_Setpoint: the load current intensity reference, P_ChargeAvailable_bcb_est: the maximum electrical power that can be supplied by the charger, P_ChargeMax_bhv_est: the maximum electrical power that can be received in the battery, Volt_HVNet_Triangulation_mes: the electrical voltage of the network supplied by the drums. 6. Charging method according to one of the preceding claims, characterized in that the regulation phase is activated when the battery charge level is below a predefined threshold. 7. Charging method according to one of the preceding claims, characterized in that information of maximum electrical power that can be provided by the charger is transmitted by the charger and / or information of maximum electrical power that can be received by the battery is emitted by the battery. 8. Charging method according to one of the preceding claims, characterized in that the regulating phase comprises a step of saturation of the control of the intensity of the charging current of the battery. 9. Data storage medium readable by a computer (3) on which is recorded a computer program comprising software means for implementing the steps of the method according to one of the preceding claims. 10. Computer (3) comprising hardware and / or software means for implementing the charging method according to one of claims 1 MS \ REN232FR.dpt.doc to 8, in particular implementation of the control phase of claim 1. 11. Calculator (3) according to claim 10, characterized in that the hardware and / or software comprises a generator (69) charge current intensity setpoint and a regulator (70). 12. Calculator (3) according to claim 11, characterized in that the hardware and / or software means comprise a subtractor (64) calculating the difference between the charging current intensity setpoint and a measurement of the current intensity. charge. 13. Device (8) for charging a battery (1) for supplying a driving motor of a motor vehicle, characterized in that it comprises a computer according to one of claims 10 to 12 and a charger (2). 14. Motor vehicle, characterized in that it comprises a computer according to one of claims 10 to 12 or a charging device (8) according to the preceding claim. MS \ REN232FR.dpt.doc