FR3137879A1 - METHOD FOR PROTECTING ELECTRICAL POWER COMPONENTS OF A VEHICLE - Google Patents

Abstract

One aspect of the invention relates to a method (100) for protecting electrical components of an electrical power network of a vehicle comprising the steps of: Determine (101) an internal resistance in charging and discharging of a power battery; Determine (102) a no-load voltage of the battery; Determine (103) a minimum and maximum voltage of electrical components, Determine (104) a first limit current for charging and discharging the battery as a function of said determined resistances and voltages; (105) a first limit power in charging and discharging of said battery as a function of said first limit currents in charge and discharge, said minimum and maximum voltages and a second current or a second limit power in charge and discharge , Limit (106) the charging and discharging power of said battery, said first determined limit power. Figure 1

Description

METHOD FOR PROTECTING POWER ELECTRICAL COMPONENTS OF A VEHICLE

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 an automobile, constructed and arranged to implement a method for protecting electrical power components.

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

Such vehicles are usually equipped with electrical power components that can be supplied at 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.

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

According to such an example, when the voltage supplied to the air conditioning compressor is less than 200V, the latter may be disabled. Conversely, when the voltage supplied to the air conditioning compressor is greater than 450V, the operation of the latter may be damaged.

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.

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

• Déterminer une résistance interne en charge et une résistance interne en décharge d’une batterie de puissance dudit véhicule ;
• Déterminer une tension à vide de ladite batterie de puissance ;
• Déterminer une tension minimale de fonctionnement et une tension maximale de fonctionnement de composants électriques dudit réseau électrique de puissance ;
• Déterminer un premier courant limite en charge et un premier courant limite en décharge de ladite batterie de puissance ; lesdits premiers courants limites en charge et en décharge étant déterminés en fonction desdites résistances internes en charge et en décharge déterminées, de ladite tension à vide déterminée et desdites tensions minimale et maximale de fonctionnement déterminées ;
• Déterminer une première puissance limite en charge et une première puissance limite en décharge de ladite batterie de puissance, lesdites premières puissances limites en charge et en décharge étant fonction :
  • desdits premiers courants limites en charge et en décharge déterminés,
  • desdites tensions minimale et maximale de fonctionnement déterminées, et
  • d’un deuxième courant limite en charge et d’un deuxième courant limite en décharge ou d’une deuxième puissance limite en charge et une deuxième puissance limite en décharge, lesdits deuxièmes courants et puissances limites étant déterminés indépendamment des tensions minimale et maximale de fonctionnement déterminées ;
• Limiter la puissance en charge et la puissance en décharge de ladite batterie de puissance auxdites premières puissances limites en charge et en décharge déterminées.

In this context, the invention thus relates, in its broadest sense, to a method for protecting electrical components of an electrical power network of an electric or hybrid vehicle, the method comprising the steps, carried out 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 an open-circuit voltage of said power battery;
• Determine a minimum operating voltage and a maximum operating voltage of electrical components of said power electrical network;
• Determining 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 said determined minimum and maximum operating voltages, and
  • of a second limit current under load and a second limit current under discharge or of 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 limit powers.

By means of the method according to the invention, the first limit powers in charge and 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.

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.

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.

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.

According to a non-limiting aspect of the invention, the active electrical components are identified based on electrical signals transmitted by said active electrical components.

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

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.

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

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

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

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

The invention and its various applications will be better understood by reading the description which follows and by examining the figures which accompany it.

schematically represents a non-limiting mode of implementation of the method according to the invention.

schematically illustrates a vehicle according to a non-limiting aspect of the invention.

There 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.

• Une unité de contrôle véhicule (plus connue sous l’acronyme VCU pour Vehicle Control Unit en anglais),
• Un calculateur moteur multifonctions, et
• Un système de contrôle batterie (plus connu sous l’acronyme BMS pour Batterie Management System en anglais).

In a non-limiting exemplary embodiment, the steps of the method 100 are executed by vehicle control means which can be formed by:

• A vehicle control unit (better known by the acronym VCU for Vehicle Control Unit in English),
• A multifunction engine calculator, and
• A battery management system (better known by the acronym BMS for Battery Management System in English).

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

• D’un état de charge (plus connu sous l’acronyme SoC pour State of Charge en anglais),
• D’un état de santé (plus connu sous l’acronyme SoH pour State of Health en anglais), et/ou
• D’une température de la batterie de puissance.

In a non-limiting implementation, the internal resistances during charge and discharge are determined according to:

• From a state of charge (better known by the acronym SoC for State of Charge in English),
• Of a state of health (better known by the acronym SoH for State of Health in English), and/or
• From a power battery temperature.

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 performs the determining step 101.

In a different, non-limiting implementation, the internal resistances during charge and discharge are determined by the battery control system and then transmitted to the vehicle control unit.

The method 100 also comprises a step of determining 102 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.

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

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.

The electrical power network may for example be formed by an electrical network electrically supplied with a voltage of 48 V or 400 V. 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 referred to by the skilled person 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 referred to by the skilled person by a DC/DC converter for "Direct Current/Direct Current" in English.

In our example, the electric traction machine, the air conditioning compressor, the on-board charger and the direct-direct current converter form the electrical components of the power grid.

• De composants actifs du réseau électrique de puissance,
• De plages de tension de fonctionnement de chacun des composants électriques, et
• De priorités de fonctionnement des composants électriques.

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 electrical component, and
• Of operating priorities of electrical components.

In other words, if certain electrical components of the power grid are not active, they will not be taken into consideration when determining the minimum and maximum operating voltages.

In a non-limiting embodiment, the active electrical components are identified based on 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.

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.

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.

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.

In this non-limiting exemplary 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.

• Des résistances internes en charge et en décharge déterminées,
• De la tension à vide déterminée, et
• Des tensions minimale et maximale de fonctionnement déterminées.

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 according to

• Internal resistances under load and discharge determined,
• From the determined no-load voltage, and
• Minimum and maximum operating voltages determined.

For example,

• Icharge1 = premier courant limite en charge ;
• Uocv = tension à vide ;
• Umax = tension maximale de fonctionnement ;
• Rinternecharge = résistance interne en charge.

With,

• Icharge1 = first limit current under load;
• Uocv = open circuit voltage;
• Umax = maximum operating voltage;
• Rinternecharge = internal resistance under load.

For example,

• Idecharge1 = premier courant limite en décharge ;
• Uocv = tension à vide ;
• Umin = tension minimale de fonctionnement ;
• Rinternedecharge = résistance interne en décharge.

With,

• Idecharge1 = first limit current in discharge;
• Uocv = open circuit voltage;
• Umin = minimum operating voltage;
• Rinternedecharge = internal resistance during discharge.

• Des premiers courants limites en charge et en décharge déterminés,
• Des tensions minimale et maximale de fonctionnement déterminées, et
• D’un deuxième courant limite en charge ainsi que d’un deuxième courant limite en décharge ou d’une deuxième puissance limite en charge et une deuxième puissance limite en décharge ; lesdits deuxièmes courants et puissances limites étant déterminés indépendamment des tensions minimale et maximale de fonctionnement déterminées.

The method 100 comprises a step of determining 105 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
• Of a second limit current under load as well as a second limit current under discharge or of 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.

These second currents and 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.

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.

First strategy:

• Pcharge1 = première puissance limite en charge ;
• ;
• Icharge1 = premier courant limite en charge ;
• Icharge2 = deuxième courant limite en charge ;
• Umax = tension maximale de fonctionnement ;
• Pcharge2 = deuxième puissance limite en charge.

With,

• Pcharge1 = first limit power under load;
• ;
• Icharge1 = first limit current under load;
• Icharge2 = second limit current under load;
• Umax = maximum operating voltage;
• Pcharge2 = second limit power under load.

• Pdecharge1 = première puissance limite en décharge ;

• Idecharge1 = premier courant limite en décharge ;
• Idecharge2 = deuxième courant limite en décharge ;
• Umin = tension minimale de fonctionnement ;
• Pdecharge2 = deuxième puissance limite en décharge.

With,

• Pdecharge1 = first limit power in discharge;

• Idecharge1 = first limit current in discharge;
• Idecharge2 = second discharge limit current;
• Umin = minimum operating voltage;
• Pdecharge2 = second limit power in discharge.

Second strategy:

• Pcharge1 = première puissance limite en charge ;

With,

• Pcharge1 = first limit power under load;

• Pcharge2 = second limit power under load.

• Pdecharge1 = première puissance limite en décharge ;

With,

• Pdecharge1 = first limit power in discharge;

• Pdecharge2 = second limit power in discharge.

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.

There 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 (10)

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),
• Determining (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 discharge being a function of:
  • of said first determined limit currents in charge and discharge,
  • of said determined minimum and maximum operating voltages, and
  • of a second limit current under charge and a second limit current under discharge or of a second limit power under charge and a second limit power under discharge, said second limit currents and powers being determined independently of the minimum and maximum operating voltages determined;
• Limiting (106) the charging power and the discharging power of said power battery to said first determined charging and discharging limit powers.

Method (100) according to claim 1, characterized in that 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. Method (100) according to any one of the preceding claims, characterized in that the minimum and maximum operating voltages determined are functions of active electrical components of the electrical power network, of operating voltage ranges of each of said electrical components and of operating priorities of said electrical components. Method (100) according to the preceding claim, characterized in that the active electrical components are identified as a function of electrical signals transmitted by said active electrical components. Method (100) according to claim 3, characterized in that the active electrical components are identified according to an operating mode of the vehicle (1). Method (100) according to any one of claims 3 to 5, characterized in that the minimum and maximum operating voltages determined are also a function of a minimum voltage and a maximum voltage of the power battery. 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. Method (100) according to any one of claims 1 to 6, characterized in that the no-load voltage is determined by a battery control system. Method (100) according to any one of claims 1 to 6, characterized in that the internal resistances during charge and discharge are determined by a battery control system. 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.