FR3147748A1 - Vehicle power supply electrical system - Google Patents

Abstract

The invention relates to a method for managing the reactive power consumed by an on-board charger (31) for a motor vehicle, said vehicle comprising at least one battery (20), said on-board charger (31) being on the one hand connected to the battery (20) and on the other hand intended to be connected to an external power supply network (40) to the vehicle, said on-board charger (31) being characterized by a predefined maximum threshold value of apparent power, said external power supply network (40) being capable of supplying an electrical voltage, said on-board charger (31) being configured to: consume a so-called "apparent" power, from the voltage supplied by the external network (40), in order to recharge the battery (20), supply a so-called "reactive" power to the external network (40). Figure for the abstract: Fig 1

Description

Vehicle power supply electrical system

The invention relates to the field of hybrid or electric vehicles, and more specifically to a method for managing the power consumed by an on-board charger of a motor vehicle.

As is known, an electric or hybrid vehicle comprises an electric motor and at least one battery for supplying electrical energy to the various electrical equipment of the vehicle, in particular the electric motor.

In order to recharge the vehicle batteries, it is known to electrically connect the batteries to a charging station external to the vehicle. The charging station is connected to an electrical supply network and is therefore capable of providing an alternating supply voltage. This type of charging station is known to those skilled in the art by the name “EVSE” for “Electrical Vehicle Supply Equipment” in English.

The vehicle also includes an AC-DC voltage converter connected on the one hand to the batteries and intended to be connected on the other hand to the charging station, in order to convert the AC supply voltage provided by the charging station into a DC voltage capable of recharging the batteries.

A control unit is used to control the power supplied by the charging station, and therefore by the network, to each battery. The control unit receives in particular an initial instruction corresponding to the active power of each battery, the active power defining the power consumed by a battery on the external power supply network.

In addition, it is also possible that a so-called "reactive" power request is issued to the on-board charger, so that the charger also provides reactive power into the external network, in order to rectify the power factor of the network. Thus, in this way, the on-board charger makes it possible to compensate, in other words to correct, the phase shift between the voltage and the current in the external supply network, by providing part of its power into this network.

However, when the "apparent power", defined by the root of the sum of the squares of the active power and the reactive power, consumed by the on-board charger is high, this can create an overload of electrical energy converted by the on-board charger, and therefore overheating which can damage the various electrical power components of the charger.

In order to detect excess energy consumption, it is known to regularly measure the value of the active current supplied by the on-board charger to the battery and the value of the reactive current supplied by the on-board charger to the external network. The sum of the currents thus measured is then compared to a maximum threshold. It is therefore necessary to integrate into the calculator functions configured to control the charger and to check its correct operation and complex functions and devices to determine the phasing between the current and the voltage.

There is therefore a need for a solution to overcome, at least in part, the drawbacks described above.

• consommer une puissance dite « apparente », à partir de la tension fournie par le réseau externe, afin de recharger la batterie,
• fournir une puissance dite « réactive » au réseau externe,

ledit véhicule comprenant une unité de contrôle apte à mettre en œuvre le procédé, le procédé comprenant les étapes consistant à :

1. déterminer la valeur de la puissance apparente consommée par le chargeur embarqué,
2. déterminer la valeur de la puissance réactive maximale pouvant être fournie au réseau d’alimentation externe de sorte que la puissance apparente soit inférieure ou égale à la valeur du seuil de puissance apparente maximal,
3. commander la puissance réactive fournie par le chargeur embarqué au réseau d’alimentation externe, de sorte que ladite puissance réactive soit inférieure ou égale à la puissance réactive maximale déterminée.

To this end, the invention relates to a method for managing the reactive power consumed by an on-board charger for a motor vehicle, said vehicle comprising at least one battery, said on-board charger being on the one hand connected to the battery and on the other hand intended to be connected to a power supply network external to the vehicle, said on-board charger being characterized by a predefined maximum threshold value of apparent power, said external power supply network being capable of supplying an electrical voltage, said on-board charger being configured to:

• consume so-called “apparent” power, from the voltage supplied by the external network, in order to recharge the battery,
• provide so-called “reactive” power to the external network,

said vehicle comprising a control unit capable of implementing the method, the method comprising the steps of:

1. determine the value of the apparent power consumed by the on-board charger,
2. determine the value of the maximum reactive power that can be supplied to the external power supply network so that the apparent power is less than or equal to the value of the maximum apparent power threshold,
3. control the reactive power supplied by the on-board charger to the external power supply network, so that said reactive power is less than or equal to the determined maximum reactive power.

Maximum apparent power was predetermined based on the physical and technical characteristics of the on-board charger, and in particular the power factor corrector and its hardware design, in other words its structure, and based on the limitations of the charging station.

The method thus implemented has the advantages of studying only the apparent power, in order to control the reactive power. It is therefore not necessary to know and measure the active power and the reactive power and therefore it is also not necessary to measure the phase shift between the effective voltage URMS and the effective current IRMS between the electrical network and the on-board charger.

1. émettre une commande de puissance réactive au chargeur embarqué, égale à la puissance réactive maximale, si la valeur de la requête en puissance réactive est supérieure à la puissance réactive maximale,
2. émettre une commande de puissance réactive au chargeur embarqué, égale à la valeur de puissance de la requête reçue, si la valeur de la requête en puissance réactive est inférieure à la puissance réactive maximale.

Preferably, the reactive power control step comprises the substeps consisting of, when the control unit receives a request for reactive power to be supplied by the on-board charger:

1. issue a reactive power command to the on-board charger, equal to the maximum reactive power, if the value of the reactive power request is greater than the maximum reactive power,
2. issue a reactive power command to the on-board charger, equal to the power value of the received request, if the value of the reactive power request is less than the maximum reactive power.

So, in this way, the maximum reactive power is never exceeded, nor is the maximum apparent power. Indeed, the apparent power is proportional to the reactive power.

More preferably, the step of determining the value of the apparent power corresponds to the multiplication of the value of the voltage U _RMS and the value of the current I _RMS between the electrical network and the on-board charger. These values are simple values to measure. In addition, usually, sensors of voltage U _RMS and current I _RMS between the electrical network and the on-board charger are already integrated into the vehicle. This method makes it possible to use sensors already present in the vehicle.

• consommer une puissance dite « apparente » à partir de la tension fournie par le réseau externe, afin de recharger la batterie,
• fournir une puissance dite « réactive » au réseau externe,

l’unité de contrôle étant configurée pour mettre en œuvre le procédé tel que présenté précédemment.The invention also relates to an on-board charger control unit for a motor vehicle, said vehicle comprising at least one battery, said on-board charger being on the one hand connected to the battery and on the other hand intended to be connected to a power supply network external to the vehicle, said on-board charger being characterized by a predefined maximum threshold value of apparent power, said external power supply network being capable of supplying an electrical voltage, said on-board charger being configured to:

• consume so-called “apparent” power from the voltage supplied by the external network, in order to recharge the battery,
• provide so-called “reactive” power to the external network,

the control unit being configured to implement the method as presented previously.

1. consommer une puissance dite « apparente » à partir de la tension fournie par le réseau externe, afin de recharger la batterie,
2. fournir une puissance dite « réactive » au réseau externe.

The invention also relates to a power supply system for a motor vehicle comprising at least one battery, said system comprising an on-board charger and a control unit as presented previously, the on-board charger being on the one hand connected to the battery and on the other hand intended to be connected to a power supply network external to the vehicle, said on-board charger being characterized by a predefined maximum apparent power threshold value, said on-board charger being configured to:

1. consume so-called “apparent” power from the voltage supplied by the external network, in order to recharge the battery,
2. provide so-called “reactive” power to the external network.

The invention finally relates to a motor vehicle comprising an electrical power supply system as described above.

Other features and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and must be read in conjunction with the attached drawings in which:

There is a schematic representation of the power supply system according to the invention.

There is a representation of the process of managing the power supplied by a power system charger according to the .

Vehicle

The hybrid or electric vehicle comprises an electric motor 10, a battery 20 and a power system 30.

Battery 20

The battery 20 is used to supply the electric motor 10 with electrical energy.

S power supply system 30

More specifically, the power supply system 30 comprises an on-board charger 31 and a control unit 32. The power supply system 30 may also comprise a regulator.

The on-board charger 31, more commonly called “OBC” for “on board charger” by those skilled in the art, is connected to the battery 20.

Typically, the on-board charger 31 comprises a power factor corrector, commonly referred to as a “PFC”, for “Power Factor Corrector” in English, and a linking capacitor, commonly referred to as a “DCLink” by those skilled in the art. The power factor corrector makes it possible to convert an AC voltage into a DC voltage and the linking capacitor makes it possible to eliminate residual oscillations of a DC voltage resulting from the conversion of an AC voltage into a DC voltage.

More specifically, the on-board charger 31 is also intended to be connected to a charging station external to the vehicle. Said charging station is connected to an external electrical power supply network 40. In this way, the on-board charger 31 is able to recharge the battery 20 from the voltage supplied by the external network 40. In particular, it is defined by “active power”, the power drawn by the on-board charger 31 in order to recharge the battery 20. The active power therefore corresponds to the power transmitted from the external network 40 to the battery 20, via the on-board charger 31.

In addition, the on-board charger 31 can also make it possible to compensate for the power factor of the external network 40. To do this, a request for so-called "reactive" power P _react to be supplied to the external network 40 is sent to the on-board charger 31. In other words, the on-board charger 31 makes it possible to compensate for, in other words to correct, the phase shift between the voltage and the current in the external supply network 40, by supplying reactive power P _react into said network 40.

The on-board charger 31 is characterized by a maximum apparent power threshold value. The maximum apparent power P _{app_max} has been predetermined based on the physical and technical characteristics of the on-board charger 31, and in particular the power factor corrector and the connection capacity, and based on the limitations of the charging station. The maximum apparent power P _{app_max} represents, for example, the maximum power limit that the on-board charger 31 can provide without risking that one of its components will deteriorate.

Control unit 3 2

The control unit 32 is in particular capable of controlling the on-board charger 31. The control unit 32 is, among other things, capable of measuring or recovering, in particular via a sensor, the instantaneous apparent power P _app consumed by the on-board charger 31 in order to recharge the battery 20.

As is known, the apparent power P _app is defined as follows: P _app = √(P _{r eact} ^{2 +} P _act ² ), where P _act corresponds to the active power.

The active power P _act is imposed by the battery 20, so the only power value that can be modified in order to modify the instantaneous apparent power P _app is the reactive power P _react .

The apparent power can only vary between the instantaneous value P _app and the predefined maximum apparent power value P _{app_max} . In other words, the difference between the maximum apparent power value P _{app_max} and the determined instantaneous apparent power value P _app is used to indicate the degree of freedom regarding the possible variation for the apparent power value and therefore regarding the possible variation for the reactive power value P _react .

Thus, the control unit 32 is configured to determine the maximum reactive power P_{react_max} which can be supplied by the on-board charger 31, depending on the maximum apparent power P_{app_max} and apparent power P_appinstantaneous.

On the other hand, the control unit 32 is also configured to determine the value of the reactive power P _react to be supplied by the on-board charger 31, such that said power value P _react is less than the value of the maximum reactive power P _{react_max} and is configured to control the on-board charger 31 so that the latter supplies the determined reactive power P _react .

More precisely, when the on-board charger 31 is connected to an external network 40, the control unit 32 may be required to receive a request Pr, in other words a reactive power instruction to be supplied by the on-board charger 31 to the external network 40.

In a first case, if the received reactive power request value Pr is greater than the value of the maximum reactive power P _{react_max} , then the control unit 32 is configured to send a reactive power request to the on-board charger 31, the value of which is equal to the maximum reactive power P _{react_max} .

In a second case, if the value of the request Pr in reactive power received is less than the value of the maximum reactive power P _{react_max} , then the control unit 32 is configured to send a request for reactive power to the on-board charger 31, the value of which is equal to the value of the request Pr in reactive power received.

Actions concerning the control of the maximum reactive power P_{react_max} performed by the control unit 32 can also be performed by a regulator, also called a “proportional integral corrector”, configured to control the reactive power P_{r eact}.

The transfer function C(p) of the regulator corresponds to the following function:

with K: proportional gain and Ti: integrator gain.

Process

In reference to the , an embodiment of the method for managing the power supplied by an on-board charger 31 of a power supply system 30 as presented previously is shown. The method is implemented by the control unit 32.

As a reminder, the on-board charger 31 is characterized by a maximum apparent power threshold value P _{app_ max} .

The method comprises a step E1 of determining the value of the apparent power P _app consumed by the on-board charger 31 on the electrical network 40. For this, the control unit 32 calculates or measures or receives the value of the effective voltage U _RMS and of the effective current I _RMS between the electrical network 40 and the on-board charger 31.

The term RMS stands for "Root Mean Square value" in English and refers to the square of the average value of an alternating signal. The value of the apparent power P _app is determined by multiplying the value of the voltage U _RMS and the value of the current I _RMS .

Thus, this has the advantage that the determination of the apparent power P _app does not require measuring the phase shift between the value of the effective current I _RMS and the value of the effective voltage U _RMS .

The method then comprises a step E2 of determining the maximum reactive power P _{r eact _max} which can be supplied by the electrical network 40. In other words, the control unit 32 or the regulator determines which maximum reactive power P _{re a ct _max} can be supplied to the electrical network 40 so that the apparent power P _app is less than or equal to the maximum apparent power P _{app_max} .

When the control unit 32 receives a request P _r for reactive power intended for the on-board charger 31, the method also comprises a step E3 of controlling the on-board charger 31.

If the value of the reactive power request P _r is greater than the value of the maximum reactive power P _{react_max} , then the control unit 32 issues a reactive power command to the on-board charger 31, equal to the maximum reactive power P _{react _max} .

If the value of the power request P _r is less than the maximum reactive power P _{react_max} , then the control unit 32 issues a reactive power command to the on-board charger 31, equal to the power value of the received request P _r .

In other words, the control step E3 makes it possible to limit the reactive power command sent to the on-board charger 31 so that this power value is less than the maximum reactive power P _{react_max} .

The apparent power P _app , in other words, the square root of the sum of the squares of the active power and the reactive power, generated by the on-board charger, complies with the value of the maximum apparent power threshold P _{app_max} . This prevents any heating or overconsumption by the on-board charger 31. In other words, this prevents degradation of the electrical components due to a demand for apparent power, greater than the maximum apparent power threshold P _{app_max} .

In addition, this makes it possible to define the reactive power P _react which can be supplied by the on-board charger 31 as a function of the apparent power P _app consumed by the on-board charger 31. In other words, the active power P _act consumed by the on-board charger 31 is primarily emitted to recharge the battery 20, and not to the external network 40. The reactive power P _react is not sent to the network 40 to the detriment of recharging the battery 20.

Finally, this also makes it possible to prevent and anticipate exceeding the maximum apparent power threshold P_{app_max} before this happens.

Claims (6)

Method for managing the reactive power consumed by an on-board charger (31) for a motor vehicle, said vehicle comprising at least one battery (20), said on-board charger (31) being on the one hand connected to the battery (20) and on the other hand intended to be connected to an external power supply network (40) to the vehicle, said on-board charger (31) being characterized by a maximum threshold value (P_{app_max}) predefined apparent power, said external power supply network (40) being capable of providing an electrical voltage, said on-board charger (31) being configured to:

• consume a so-called “apparent” power (P _app ), from the voltage supplied by the external network (40), in order to recharge the battery (20),
• provide so-called “reactive” power (P _react ) to the external network (40),

said vehicle comprising a control unit (32) capable of implementing the method, the method comprising the steps of:

1. determine the value of the apparent power (P _app ) consumed by the on-board charger (31),
2. determining the value of the maximum reactive power (P _{react_max} ) that can be supplied to the external power supply network (40) so that the apparent power (P _app ) is less than or equal to the value of the maximum apparent power threshold (P _{app_max} ),
3. controlling the reactive power (P _react ) supplied by the on-board charger (31) to the external power supply network (40), so that said reactive power (P _react ) is less than or equal to the maximum reactive power (P _{react_max} ) determined.

Method according to the preceding claim, in which the step of controlling the reactive power comprises the sub-steps consisting of, when the control unit (32) receives a request (P_r) in reactive power to be provided by the on-board charger (31):

1. issue a reactive power command to the on-board charger (31), equal to the maximum reactive power (P _{react_max} ), if the value of the request (P _r ) in reactive power is greater than the maximum reactive power (P _{react_max} ),
2. issue a reactive power command to the on-board charger (31), equal to the power value of the request (P _r ) received, if the value of the request (P _r ) in reactive power is less than the maximum reactive power (P _{react_max} ).

Method according to any one of the preceding claims, in which the step of determining the value of the apparent power (P _app ) corresponds to the multiplication of the value of the voltage U _RMS and the value of the current I _RMS between the electrical network (40) and the on-board charger (31). On-board charger control unit (31) for a motor vehicle, said vehicle comprising at least one battery (20), said on-board charger (31) being on the one hand connected to the battery (20) and on the other hand intended to be connected to an external power supply network (40) to the vehicle, said on-board charger (31) being characterized by a maximum threshold value (P_{app_max}) predefined apparent power, said external power supply network (40) being capable of providing an electrical voltage, said on-board charger (31) being configured to:

1. consume a so-called “apparent” power (P _app ), from the voltage supplied by the external network (40), in order to recharge the battery (20),
2. provide so-called “reactive” power (P _react ) to the external network (40),

the control unit (32) being configured to implement the method according to any one of the preceding claims. Power supply system (30) for a motor vehicle comprising at least one battery, said system (30) comprising an on-board charger (31) and a control unit (32) according to the preceding claim, the on-board charger (31) being on the one hand connected to the battery (20) and on the other hand intended to be connected to an external power supply network (40) to the vehicle, said on-board charger (31) being characterized by a maximum threshold value (P_{app_max}) of predefined apparent power, said on-board charger (31) being configured to:

1. consume a so-called “apparent” power (P _app ), from the voltage supplied by the external network (40), in order to recharge the battery (20),
2. provide so-called “reactive” power (P _react ) to the external network (40).

Motor vehicle comprising an electrical power supply system (30) according to the preceding claim.