METHOD FOR PROTECTING POWER ELECTRICAL COMPONENTS OF A VEHICLE

Abstract

One aspect of the invention relates to a method (100) for protecting electrical components of a vehicle's power electrical network, comprising the steps of: Determining (101) the internal resistance of a power battery during charging and discharging; Determining (102) the open-circuit voltage of the battery; Determining (103) the minimum and maximum voltage of electrical components; Determining (104) a first current limit during charging and discharging the battery as a function of said resistances and voltages determined; Determining (105) a first power limit during charging and discharging the battery as a function of said first current limits during charging and discharging, said minimum and maximum voltages, and a second current or power limit during charging and discharging; Limiting (106) the power during charging and discharging the battery to said first determined power limit. Figure 1

Description

Title of the invention: METHOD FOR PROTECTING ELECTRICAL COMPONENTS OF VEHICLE POWER

[0001] One aspect of the invention relates to a method for protecting electrical power components included in a vehicle. Another aspect of the invention relates to a vehicle, in particular a motor vehicle, constructed and arranged to implement a method for protecting electrical power components.

[0002] These aspects of the invention find particularly interesting applications in the field of electric or hybrid vehicles.

[0003] Such vehicles are usually equipped with electrical power components that can be powered according to a voltage provided by a power battery, for example 48V or 400V. These electrical power components can for example be formed by an electric traction machine of the vehicle or by an air conditioning compressor of the vehicle.

[0004] Each of these power electrical components has an operating voltage range. For example, some air conditioning compressors may have a minimum operating voltage of 200V and a maximum operating voltage of 450V.

[0005] According to such an example, when the voltage supplied to the air conditioning compressor is less than 200V, the latter can be deactivated. Conversely, when the voltage supplied to the air conditioning compressor is greater than 450V, the operation of the latter can be damaged.

[0006] Document WO-A1-2021224327 discloses a method for managing the charge and discharge currents admissible by the components constituting an electric battery of a vehicle. On the other hand, it does not make it possible to protect all the electrical components of a high-power network of a vehicle against undervoltages and overvoltages.

[0007] The aim of the invention is to overcome the drawbacks of the prior art by proposing a method for protecting electrical power components in a vehicle against undervoltages and overvoltages.

[0008] In this context, the invention thus relates, in its broadest acceptance, to a method for protecting electrical components of an electrical power network of an electric or hybrid vehicle, the method comprising the steps, executed by control means of the vehicle, of: • Determine an internal resistance under load and an internal resistance under discharge of a power battery of said vehicle; • Determine the no-load voltage of said power battery; • Determine a minimum operating voltage and a voltage maximum operating time of electrical components of said electrical power network; • Determine a first limit current in charge and a first limit current in discharge of said power battery; said first limit currents in charge and discharge being determined as a function of said determined internal resistances in charge and discharge, of said determined no-load voltage and of said determined minimum and maximum operating voltages; • Determine a first limit power in charge and a first limit power in discharge of said power battery, said first limit powers in charge and discharge being a function of: • of said first determined limit currents in charge and discharge, • of the said minimum and maximum operating voltages determined, and • a second limit current under load and a second limit current under discharge or a second limit power under load and a second limit power under discharge, said second limit currents and powers being determined independently of the minimum and maximum operating voltages determined; • Limit the charging power and the discharging power of said power battery to said first determined charging and discharging power limits.

[0009] Thanks to the method according to the invention, the first limit powers in charge and in discharge are determined so as not to exceed the minimum voltage, or even the maximum voltage, of the plurality of electrical components equipping the electrical power network of the vehicle. Thus, there is no risk of deactivation or damage to one of the electrical components of the electrical power network.

[0010] In addition to the characteristics which have just been mentioned in the preceding paragraph, the method according to this aspect of the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations.

[0011] According to a non-limiting aspect of the invention, the internal resistances during charging and discharging are determined as a function of a state of charge, a state of health and a temperature of the power battery.

[0012] According to a non-limiting aspect of the invention, the minimum and maximum operating voltages determined are a function of active electrical components of said electrical power network, operating voltage ranges of each of said components and operating priorities of said electrical components.

[0013] According to a non-limiting aspect of the invention, the active electrical components are identified as a function of electrical signals transmitted by said active electrical components.

[0014] According to a non-limiting aspect of the invention, the active electrical components are identified according to an operating mode of the vehicle.

[0015] According to a non-limiting aspect of the invention, the minimum and maximum operating voltages determined are also a function of a minimum voltage and a maximum voltage of the power battery.

[0016] According to a non-limiting aspect of the invention, the steps are executed by a vehicle control unit or a multifunction engine computer.

[0017] According to a non-limiting aspect of the invention, the no-load voltage is determined by a battery control system.

[0018] According to a non-limiting aspect of the invention, the internal resistances during charging and discharging are determined by a battery control system.

[0019] Another aspect of the invention relates to an electric or hybrid vehicle comprising control means arranged to implement the method for protecting electrical components of the vehicle's electrical power network according to any one of the aforementioned aspects of the invention.

[0020] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures.

[0021] [Fig-1] schematically represents a non-limiting mode of implementation of the method according to the invention.

[0022] [Fig.2] illustrates, schematically, a vehicle according to a non-limiting aspect of the invention.

[0023] [Fig.l] shows the steps of an embodiment of the method 100 for protecting electrical components of an electrical power network of an electric or hybrid vehicle according to one aspect of the invention.

[0024] In a non-limiting exemplary embodiment, the steps of the method 100 are executed by vehicle control means which may be formed by: • A vehicle control unit (better known by the acronym VCU for Vehicle Control Unit in English), • A multifunction engine computer, and • A battery control system (better known by the acronym BMS for Battery Management System in English).

[0025] The method 100 comprises a step 101 of determining an internal resistance under load and an internal resistance under discharge of a power battery of the vehicle.

[0026] In a non-limiting implementation, the internal resistances during charging and discharging are determined as a function of: • A state of charge (better known by the acronym SoC for State of Charge in English), • A state of health (better known by the acronym SoH for State of Health in English), and / or • A power battery temperature.

[0027] The internal resistances during charging and discharging are determined, for example, by means of maps reporting the state of charge, the state of health and the temperature. These parameters can for example be transmitted by the battery control system to the vehicle control unit, which then executes the determining step 101.

[0028] In a different non-limiting implementation, the internal resistances during charging and discharging are determined by the battery control system, then transmitted to the vehicle control unit.

[0029] The method 100 also comprises a step 102 of determining the no-load voltage of the power battery. This no-load voltage can, for example, be determined by means of a map reporting a state of charge as a function of a temperature. This step can, for example, be executed by the vehicle control unit.

[0030] In a different, non-limiting implementation, this no-load voltage is determined by the battery control system, then transmitted to the vehicle control unit.

[0031] The method 100 comprises a step 103 of determining a minimum operating voltage and a maximum operating voltage of electrical components of the vehicle's electrical power network.

[0032] The electrical power network may for example be formed by an electrical network electrically supplied by a voltage of 48V or 400V. Such an electrical power network may for example comprise an electric traction machine, an air conditioning compressor, an on-board charger arranged to charge the power battery of the vehicle, such an on-board charger being commonly designated by those skilled in the art by the acronym OBC for "On Board Charger" in English, and a direct-direct current converter arranged to electrically supply a service battery and the on-board network of the electric vehicle, such a direct-direct current converter being commonly designated by those skilled in the art by a DC / DC converter for "Direct Current / Direct Current" in English.

[0033] The electric traction machine, the air conditioning compressor, the on-board charger and the direct-direct current converter form, in our example, the electrical components of the power electrical network.

[0034] In a non-limiting exemplary embodiment, the minimum and maximum operating voltages are determined as a function of: • Active components of the power electrical network, • Operating voltage ranges of each of the electrical components, and • Operating priorities of electrical components.

[0035] In other words, if certain electrical components of the power electrical network are not active, they will not be taken into consideration to determine the minimum and maximum operating voltages.

[0036] In a non-limiting embodiment, the active electrical components are identified according to an operating mode of the vehicle. For example, when the vehicle is in an operating mode, called Drive in English, the vehicle control unit is able to determine that the electric traction machine, the air conditioning compressor and the direct-direct current converter are active but that the on-board charger is inactive.

[0037] In a different embodiment, the active electrical components are identified based on electrical signals transmitted by said active electrical components. These electrical signals can be identified by the vehicle control unit.

[0038] In a non-limiting implementation, the operating voltage range of an active electrical component may be determined by means of a map providing for this electrical component an operating voltage range as a function of its temperature. This operating voltage range may be determined by the vehicle control unit. In another implementation, the operating voltage range is transmitted by the component itself to the vehicle control unit.

[0039] In a non-limiting embodiment, the operating priorities of the electrical components may depend on safety, performance and comfort parameters. A safety component, for example an electric traction machine used to brake the vehicle, will have priority over a comfort component, for example the air conditioning compressor.

[0040] In this non-limiting example embodiment, the vehicle control unit will select the voltage range of the electric traction machine which is active and has priority over the air conditioning compressor.

[0041] The method 100 comprises a step of determining 104 a first limit current in charge and a first limit current in discharge of the power battery. The first limit currents in charge and discharge are determined as a function of • The determined internal resistances in charge and discharge, • The determined no-load voltage, and • The determined minimum and maximum operating voltages.

[0042] For example, / cWgel =

[0043] With, • Ichargel = first limit current under load; • Uocv = open-circuit voltage; • Umax = maximum operating voltage; • Rinternecharge = internal resistance under load.

[0044] For example, Idechargei = max(0.

[0045] With, • Idechargel = first limit current in discharge; • Uocv = open-circuit voltage; • Umin = minimum operating voltage; • Rinternedecharge = internal resistance during discharge.

[0046] The method 100 comprises a step 105 of determining a first limit power in charge and a first limit power in discharge of the power battery. The first limit powers in charge and in discharge are a function of: • First determined limit currents in charge and discharge, • Determined minimum and maximum operating voltages, and • A second limit current under load as well as a second limit current under discharge or a second limit power under load and a second limit power under discharge; said second limit currents and powers being determined independently of the minimum and maximum operating voltages determined.

[0047] These second currents and these second limit powers in charge and discharge can be determined by the BMS system by means of mapping and then transmitted to the vehicle control unit.

[0048] According to two non-limiting embodiments, the first limit powers in charge and discharge of the power battery can be determined according to two strategies.

[0049] First strategy:

[0050] Pchargeï = m&(lsyncharge*Umax, Pchargel}

[0051] With, • Pchargel = first limit power under load; • Isyncharge-mzx{lchargel, Ichargel!)', • Ichargel = first limit current under load; • Icharge2 = second limit current under load; • Umax = maximum operating voltage; • Pcharge2 = second limit power under load.

[0052] PdechargeV-màsilsyndecharge^Unùn, Pdecharge!)

[0053] With, • Pdechargel = first limit power in discharge; Isyndecharge = vw^(ldecharge\, I discharged!) • Idechargel = first limit current in discharge; • Idecharge2 = second limit current in discharge; • Umin = minimum operating voltage; • Pdecharge2 = second limit power in discharge.

[0054] Second strategy:

[0055] Pcharge\ = mwéjsynchargeWmaxlim, Pcharged!)

[0056] With, • Pchargel = first limit power under load; Isyncharge = maAlcharge 1, Icharge!)

[0057] u maxlim = Uocv + Isyncharge*Rinternecharge) • Pcharge2 = second limit power under load.

[0058] Pdecharge\ = mÿ^Isyndecharge*Unûnlim, Pdechargeü)

[0059] With, • Pdechargel = first limit power in discharge; Isyndecharge = va&\{ldecharge\, Idecharge!)

[0060] Unünlim = Uocv - Isyndecharge*Rintemedecharge) • Pdecharge2 = second limit power in discharge.

[0061] The method 100 then comprises a step 106 of limiting the charging power and the discharging power of the power battery to said first determined charging and discharging limit powers.

[0062] [Fig. 2] illustrates a vehicle 1 according to a non-limiting aspect of the invention. The vehicle 1 may be an electric or hybrid vehicle. This vehicle 1 comprises control means 2 arranged to implement the method 100 for protecting electrical components of the electrical power network described above.

Claims

1. Claims Method (100) for protecting electrical components of an electrical power network of an electric or hybrid vehicle (1), the method (100) comprising the steps, executed by control means (2) of said vehicle (1), of: • Determine (101) an internal resistance under load and an internal resistance under discharge of a power battery of said vehicle; • Determine (102) an open-circuit voltage of said power battery; • Determine (103) a minimum operating voltage and a maximum operating voltage of electrical components of said electrical power network of said vehicle (1), the minimum and maximum operating voltages determined being a function of active electrical components of the electrical power network, operating voltage ranges of each of said electrical components and operating priorities of said electrical components. • Determine (104) a first limit current in charge and a first limit current in discharge of said power battery; said first limit currents in charge and discharge being determined as a function of said determined internal resistances in charge and discharge, of said determined no-load voltage and of said determined minimum and maximum operating voltages; • Determine (105) a first limit power in charge and a first limit power in discharge of said power battery, said first limit powers in charge and in discharge being a function of: • of said first determined limit currents in charge and discharge, • of said determined minimum and maximum operating voltages, and • a second limit current in charge and a second limit current in discharge or a second limit power in charge and a second p discharge power limit, said second currents and power limits being determined independently of the determined minimum and maximum operating voltages; • Limiting (106) the charging power and the discharging power of said power battery to said first determined charging and discharging power limits.

2. Method (100) according to claim 1, characterized in that the internal resistances in charge and discharge are determined as a function of a state of charge, a state of health and a temperature of the power battery.

3. Method (100) according to the preceding claim, characterized in that the active electrical components are identified based on electrical signals transmitted by said active electrical components.

4. Method (100) according to any one of the preceding claims, characterized in that the active electrical components are identified according to an operating mode of the vehicle (1).

5. Method (100) according to any one of the preceding claims, characterized in that the determined minimum and maximum operating voltages are also a function of a minimum voltage and a maximum voltage of the power battery.

6. Method (100) according to any one of the preceding claims, characterized in that the steps are executed by a vehicle control unit or a multifunction engine computer.

7. Method (100) according to any one of claims 1 to 5, characterized in that the no-load voltage is determined by a battery control system.

8. Method (100) according to any one of claims 1 to 5, characterized in that the internal resistances during charging and discharging are determined by a battery control system.

9. Electric or hybrid vehicle (1) characterized in that it comprises control means (2) arranged to implement the method (100) for protecting electrical components of the electrical power network of said vehicle (1) according to any one of the preceding claims.

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