WO2020187814A1

WO2020187814A1 - Method for controlling the electromagnetic relays of an electric or hybrid motor vehicle

Info

Publication number: WO2020187814A1
Application number: PCT/EP2020/057031
Authority: WO
Inventors: Elise JEAN; Thibaud ROLLAND; Arnaud SZEWCZYK
Original assignee: Renault S.A.S; Nissan Motor Co., Ltd.
Priority date: 2019-03-18
Filing date: 2020-03-16
Publication date: 2020-09-24
Also published as: FR3094150B1; FR3094150A1

Abstract

The invention relates to a method (1) for controlling electromagnetic relays (25) of an electric or hybrid motor vehicle (20) comprising an electric storage battery (26) defining a set voltage, EVTargetVoltage, said motor vehicle being connected to an electric charging terminal (21) delivering a charging voltage, EVSEPresentVoltage, said method (1) comprising: - a step of controlling the closing of the electromagnetic relays 25 if the acquired charging voltage value, EVSEPresentVoltage, at the current instant t, is evaluated during the first evaluation step (11) as being stabilised, and if the deviation between the acquired charging voltage, EVSEPresentVoltage, at the current instant and the set voltage, EVTargetVoltage, is evaluated as being lower than said first voltage threshold.

Description

Title of the invention: Method for controlling the electromagnetic relays of an electric or hybrid motor vehicle The present invention relates to a method for controlling the electromagnetic relays of an electric or hybrid motor vehicle.

In the field of electric and hybrid motor vehicles, it is well known to control the connection of the battery terminals by electromagnetic relays, more simply called relays. The battery referred to in this application is a "traction battery", that is to say the high voltage battery supplying the electric powertrain, the associated vehicle being able to operate in traction or in propulsion.

Referring to Figure 1 showing a charging assembly of an electric or hybrid motor vehicle 20 known from the prior art, the motor vehicle 20 is connected by an electric cable 27 to an electric charging station 21.

The motor vehicle 20 comprises an electric accumulator battery 26, also called more simply battery 26, connected on the one hand to the power members of the vehicle such as the inverter, and on the other hand to direct voltage electromagnetic relays 25, also called DC 25 relays or more simply 25 relays.

When these relays 25 are open, the battery 26, forming part of the power units of the motor vehicle, is able to supply the electrical energy necessary for the power units of the motor vehicle. However in this state, the relays 25 prevent the recharging of the battery 26.

When the relays 25 are closed, then the battery 26 is able to receive the electrical energy supplied by the electric charging station 21.

In the context of the rapid recharging of electric or hybrid motor vehicles, it is known that a precharging step is generally required before the vehicle closes its relays 25.

During this precharging period, the recharging terminal 21 adjusts the direct DC voltage supplied to the same level as the voltage of the battery 26 of the vehicle, so that when the relays 25 are closed, the voltages are substantially balanced.

Indeed, an inrush current can occur when the relays 25 close if too great a voltage difference persists between the voltage upstream of the relays 25 and the voltage downstream of the relays 25, in other words between the voltage across the terminals. battery 26 and the voltage at the outlet of the charging station 21.

A high inrush current not only presents risks of damage to the relays 25 of the motor vehicle 20, but also leads to charging refusals on the charging stations 21 which detect a fault if the current during the precharging exceeds a certain threshold. .

Also, a known objective is to seek to optimally balance the upstream and downstream voltages of the relays 25 so as to reduce the inrush current that may occur when the relays 25 of the motor vehicle 20 close.

Several fast charging standards have been developed by car manufacturers. The COMBO standards are known in particular for direct current recharging, also called DC COMBO, and GB / T.

The IEC 61851-23 standard notably imposes normative limits for DC COMBO charging: the terminal must regulate the charging voltage during the precharging to +/- 20V of the setpoint voltage sent by the motor vehicle 20 as well as a limit of inrush current at 2A.

In order to regulate their precharge voltage, terminal manufacturers use various technical solutions.

The installation of a precharge resistor makes it possible to limit the precharge current, but some charging stations 21 do not have one and implement only software regulation.

In addition, some charging stations 21 do not have a diode allowing progressive balancing, so the inrush current depends on the voltages upstream and downstream of the relays 25 and on the impedance of the circuit. For example, it happens to measure inrush currents of up to 150A in the reverse direction, which is far beyond the desired values.

A solution to reduce the inrush current is then to add a differential sensor for the upstream / downstream voltages of the relays 25 of the motor vehicle 20. However, this solution requires costly hardware modifications which cannot necessarily be implemented in an existing fleet of vehicles.

Also, there is a need for a solution to reduce the inrush current when closing relays in a simple and robust manner without impacting the technical structures of power units.

To this end, a method is proposed for controlling electromagnetic relays of an electric or hybrid motor vehicle comprising an electric accumulator battery defining a setpoint voltage, said motor vehicle being connected to an electric charging station delivering a charging voltage. , said method comprising:

- a step of acquiring said setpoint voltage value;

- a step of acquiring said charge voltage value at a current instant and at least one other instant preceding the current instant;

- a first evaluation step, during which it is evaluated whether the value of the charge voltage acquired is stabilized between the different acquisition instants;

- a second evaluation step, during which it is evaluated whether the difference in absolute value between the charge voltage acquired at the current instant and the setpoint voltage is less than a first voltage threshold, for example 5V;

a step for controlling the closing of the electromagnetic relays 25 if the charge voltage value acquired at the current instant is evaluated during the first evaluation step as being stabilized, and if the difference in absolute value between the charge voltage acquired at the current instant and the setpoint voltage is evaluated as being below said first voltage threshold.

Thus, it is possible to obtain a method for controlling the closing of the relays of the motor vehicle that is relatively simple, robust and does not require any material adaptation whatsoever to the vehicle or to the charging station.

Advantageously and in a nonlimiting manner, the first evaluation step comprises a first sub-step during which it is estimated whether the voltage difference in absolute value between the charge voltage value at the current instant and the setpoint voltage is less than a second voltage threshold, for example 30V, greater than the first voltage threshold. So we can ensure that the charging voltage has reached a substantially stabilized value, below this second threshold, for example 30V, corresponding substantially to the maximum error that may derive from the various measurement sensors and regulation means.

Advantageously and in a nonlimiting manner, the first evaluation step comprises a second sub-step during which the difference in absolute value between the charge voltage value acquired at the current instant, and another voltage value is calculated. of charge acquired at another instant preceding said current instant, so that it is estimated during said second sub-step whether said calculated difference is less than a third voltage threshold, for example 2V, below said second voltage threshold. Thus, it is estimated whether the charging voltage has changed during a predefined time interval, for example during the last 1 5 seconds, corresponding to a time interval provided by the standards as an objective of stabilization of voltage rise of charge for charging stations.

Advantageously and in a nonlimiting manner, during the first evaluation step, it is positively evaluated that the acquired charge voltage value is stabilized if the estimates of the two sub-steps are verified. Thus, a relatively robust assessment of the stabilization of the charging voltage during the precharging period is obtained.

Advantageously and in a non-limiting manner, the second verification step is implemented only when the first verification step has positively evaluated that the value of the charge voltage acquired is stabilized, otherwise said control method begins again in its first step. Thus, it is possible to optimize the operation of the method and limit the quantity of calculations carried out.

Advantageously and in a nonlimiting manner, when during the second evaluation step, it is evaluated that the difference between the charge voltage acquired at the current instant and the setpoint voltage is between the first voltage threshold and a fourth voltage threshold, for example 30 V, then a step is carried out for modifying said setpoint voltage value as a function of said difference value between the charge voltage acquired at the current instant and the setpoint voltage, and in that said method resumes from first step with said modified setpoint voltage value. Thus, the setpoint voltage can be modified in order to take account of a potential measurement error, which may arise in particular from the various voltage sensors, so as to allow a better match between the setpoint voltage and the load voltage, and to reduce the risk of inrush currents when the relays are closed.

Advantageously and in a non-limiting manner, said modified setpoint voltage value is equal to said acquired setpoint value to which is added the difference between the setpoint voltage at the previous iteration and the charge voltage acquired at the current instant. Thus, the setpoint voltage is modified in a relatively simple and robust manner.

Advantageously and in a nonlimiting manner, when the method is repeated for a continuous period of time, for example between 30 seconds and 1 minute, due to the fact that during the first verification step it is evaluated negatively that the voltage value of acquired charge is stabilized, then an alternative verification step is implemented, during which it is evaluated whether the difference in absolute value between the charge voltage at the current instant and the setpoint voltage is between the first threshold of voltage and the second voltage threshold, so that the step of controlling the closing of the relays independently of the two evaluation steps is carried out, if necessary. Thus, a refusal of charge by the charging station can be avoided if the first verification step cannot be positively evaluated, for example because a voltage sensor is faulty, or because the voltage regulation is not enough. precise.

The invention also relates to a device for controlling the electromagnetic relays of an electric or hybrid motor vehicle comprising an electric accumulator battery defining a setpoint voltage, said motor vehicle being intended to be connected to an electric charging terminal delivering a voltage. load, adapted to implement the method as described above.

The invention also relates to an electric or hybrid motor vehicle comprising an electric accumulator battery defining a setpoint voltage, said motor vehicle further comprising relays. electromagnetic and being configured to be connected to an electric charging station delivering a charging voltage, said vehicle comprising a device for controlling electromagnetic relays as described above.

Other features and advantages of the invention will emerge on reading the description given below of a particular embodiment of the invention, given by way of indication but not limitation, with reference to the accompanying drawings in which:

[Fig. 1] is a schematic view of an electric or hybrid motor vehicle according to the invention connected to an electric charging station;

[Fig. 2] is a flowchart of the method according to the main embodiment of the invention; and

[Fig. 3] is a diagram showing the stepwise evolution of the EVSEPresentVoltage charge voltage upstream of the motor vehicle relays.

The invention relates to a method 1 for managing the charging of an electric or rechargeable hybrid motor vehicle 20, connected by an electric cable 27 adapted to an electric charging station 21, according to the ISO 15118 standard.

ISO 15118 defines the physical and data link layer requirements for high level communication, directly between battery electric vehicles or plug-in hybrid electric vehicles, based on wired communication technology, and fixed installation of electric recharging.

The motor vehicle 20 is also able to communicate with the charging station 21 via a communication channel 22, here a communication cable 22. In particular in this embodiment, the communication cable 22 corresponds to the electric cable 27, the communication being carried out by line powerline, frequently abbreviated as CPL.

In the remainder of the description, the voltage values will be named, in accordance with the standards in force in the technical field, with reference to the abbreviations EVSE 21 from the English Electric Vehicle Supply Equipment, in French motor vehicle supply equipment , in other words the electric charging station 21 of the motor vehicle, and EV, from the English Electric Vehicle, corresponding to the electric or hybrid motor vehicle.

The motor vehicle 20 includes an electric storage battery 26 separated from the charging station 21 by charging relays 25.

According to this communication standard, the motor vehicle 20 first sends a request 23, comprising a message frequently called Preloaded, requiring preloading, to the recharging terminal 21, providing a setpoint voltage value EVTargetVoltage as argument of the message.

The setpoint voltage value EVTargetVoltage corresponds here to the voltage measured at the terminals of the battery 26, therefore downstream of the relays 25, and acquired with a view to transmitting the request message 23. It is more generally the battery voltage. , measured or estimated.

A response message 24 is then sent by the charging station 21 to the motor vehicle 20 via the communication channel 22, the message being frequently called PreChargeRes (from the English Préchargé Response, in French response to the precharge request), comprising a measurement of the current voltage on the EVSEPresentVoltage recharging terminal side, in other words of the voltage upstream of the relays 25. This is therefore the direct voltage supplied by the charging terminal.

The response time provided between the request message from the motor vehicle 20 and the response from the charging station 21 to restore this measurement is provided for by the ISO 15118 standard at 1.5 seconds, leaving time at the charging station 21 to regulate its voltage to the setpoint voltage EVTargetVoltage. However, in practice this response time is much shorter.

In addition, the accuracy of the upstream voltage measurement sensor of the relays

25 in the recharging terminal 21 varies between +/- 10V, and the precision of the sensor for measuring the voltage of the battery 26 of the motor vehicle 20 varies between +/- 5V.

Consequently, the total possible difference between the two voltage measurements is +/- 15V which is relatively large, especially since the precision of the voltage regulation of the charging station 21 is +/- 20V .

Thus, although the charging station 21 may have completed its regulation to the setpoint voltage EVTargetVoltage, it may deliver a value of voltage deviating by +/- 30V from this setpoint voltage, creating an unwanted and potentially high inrush current.

The invention therefore relates to a method 1 aimed at ensuring that the voltage delivered by the charging station 21 substantially corresponds to the setpoint voltage EVTargetVoltage, so as to avoid an inrush current.

To this end, the method 1 comprises a first step of acquiring a setpoint voltage EVTargetVoltage, also called initial setpoint voltage EVTargetVoltage, corresponding to the setpoint voltage EVTargetVoltage transmitted by the motor vehicle 20 to the charging station 21 .

Method 2 then comprises a step of receiving 10 ′ of a charge voltage value EVSEPresentVoltage, corresponding to the voltage upstream of the relays 25 measured by the charging terminal 21 at the present instant, called instant t.

Then, the method implements a first evaluation step 11 of the stabilization of the measurement of the charging voltage EVSEPresentVoltage measured on the charging station 21.

Indeed, we know that some terminals increase their precharge voltage step by step during the transient regulation phase, as shown as an example in Figure 3, for a setpoint voltage of 359 V.

Thus the first stabilization evaluation step 11 comprises two sub-steps implemented substantially simultaneously and each verifying a stabilization criterion. If both stabilization criteria are met then the charge voltage EVSEPresentVoltage is considered stabilized.

On the one hand, a first stabilization criterion is checked, in the first sub-step, verifying whether the voltage difference in absolute value between the load voltage measurement EVSEPresentVoltage on the terminal 21 side and the setpoint voltage EVTargetVoltage is less than 30V.

The difference between the charge voltage value EVSEPresentVoltage at the current instant, called instant t, and the charge voltage value EVSEPresentVoltage at the instant t is calculated on the other hand, during a second sub-step -1, 5s, or as measured 1.5 seconds previously the current moment. The second criterion is then checked, during the second sub-step, verifying whether the difference in absolute value between these two charge voltage values EVSEPresentVoltage, respectively at times t and t-1 5s, is less than 2V .

The threshold value of 2V can be freely adapted by a person skilled in the art, it can for example be less than 2V, or greater than 2V, but it is advisable to keep a value as small as possible, preferably less than or equal to 2V, in order to optimize the operation of the process 1.

If the two criteria of the first evaluation step 11 are met, then a second evaluation step 12 is implemented.

If the two criteria of the first evaluation step 11 are not met, then process 1 starts over.

During the second evaluation step 12, it is checked whether the difference in absolute value between the charge voltage EVSEPresentVoltage at time t and the initial setpoint voltage EVTargetVoltage is less than 5V.

If the difference is effectively less than 5V, then the relays 25 are closed 14 and the motor vehicle 20 is recharged.

If the difference is between 5V and 30V, a step 13 is then carried out for modifying the setpoint voltage value EVTargetVoltage so that the new setpoint voltage EVTargetVoltage _new is equal to the previous setpoint voltage EVTargetVoltage to which is added the error, here the difference between the previous setpoint voltage EVTargetVoltage and the load voltage EVSEPresentVoltage at time t, i.e.:

[Math. 1]

EVTargetVoltage _new

= EVTargetVoltage

+ (EVTargetVoltage - EVSEPresentVoltage (t))

After the modification 13 of the setpoint value EVTargetVoltage _new, process 1 starts again, keeping the modified setpoint value EVTargetVoltage _new as the new setpoint value EVTargetVoltage.

This method of adjusting the EVTargetVoltage setpoint sent by the motor vehicle 20 to the charging station 21 makes it possible to reduce the error, here the voltage difference between the upstream and downstream relays 25 and therefore reduce the inrush current when the relays 25 close.

In a particular embodiment, in order to avoid a refusal to charge the charging station 21; if after 35 seconds, the criteria of the first evaluation step 11 are not met, in other words if after 35 seconds the method 1 starts again without ever fulfilling the criteria of the first evaluation step 11, a step of alternative verification, during which it is evaluated whether the difference between the load voltage EVSEPresentVoltage at time t and the initial setpoint voltage EVTargetVoltage is between 5V and 30V, and in this case we proceed directly to the closing of the relays 25 of the motor vehicle 20.

Claims

1. A control method (1) of electromagnetic relays (25) of an electric or hybrid motor vehicle (20) comprising an electric accumulator battery (26) defining a setpoint voltage, EVTargetVoltage, said motor vehicle being connected to a electric charging station (21) delivering a charging voltage, EVSEPresentVoltage, said method (1) comprising:

- a step of acquiring (10) said setpoint voltage value, EVTargetVoltage, corresponding to the voltage of the electric storage battery (26);

- a step of acquiring (10 ′) of said charge voltage value, EVSEPresentVoltage, at a current instant t, and at least one other instant preceding the current instant t;

a first evaluation step (11), during which it is evaluated whether the acquired charge voltage value, EVSEPresentVoltage, is stabilized between the different acquisition instants;

- a second evaluation step (12), during which it is evaluated whether the difference in absolute value between the acquired charge voltage, EVSEPresentVoltage, at the current instant t, and the setpoint voltage, EVTargetVoltage, is less at a first voltage threshold;

- a step of controlling the closing of the electromagnetic relays (25) if the acquired charge voltage value, EVSEPresentVoltage, at the current instant t, is evaluated during the first evaluation step (11) as being stabilized, and if the difference in absolute value between the acquired charge voltage, EVSEPresentVoltage, at the current instant t, and the setpoint voltage, EVTargetVoltage, is evaluated as being less than said first voltage threshold.

2. Control method (1) according to claim 1, characterized in that the first evaluation step (11) comprises a first sub-step during which it is estimated whether the voltage difference in absolute value between the value of charge voltage, EVSEPresentVoltage, at current time t, and the voltage of setpoint, EVTargetVoltage, is less than a second voltage threshold, greater than the first voltage threshold.

3. Control method (1) according to claim 1 or 2, characterized in that the first evaluation step (11) comprises a second sub-step during which the difference in absolute value between the voltage value is calculated. of charge acquired, EVSEPresentVoltage, at the current instant t, and another value of charge voltage, EVSEPresentVoltage, acquired at another instant preceding said current instant t, so that it is estimated during said second sub-step if said calculated difference is less than a third voltage threshold, less than said second voltage threshold.

4. Control method (1) according to claim 3 when it depends on 2, characterized in that during the first evaluation step (11), it is positively evaluated that the value of the charge voltage acquired , EVSEPresentVoltage, is stabilized if the estimates of the two substeps are true.

5. Control method (1) according to any one of claims 1 to 4, characterized in that the second verification step (12) is implemented only when the first verification step (11) has evaluated positively. that the acquired charge voltage value, EVSEPresentVoltage, is stabilized, otherwise said control method (1) begins again in its first step.

6. A control method (1) according to any one of claims 1 to 5, characterized in that when during the second evaluation step (12), it is evaluated that the difference between the charge voltage acquired, EVSEPresentVoltage, at the current instant t, and the setpoint voltage, EVTargetVoltage, is between the first voltage threshold and a fourth voltage threshold, for example 30 V, then a modification step (13) of said setpoint voltage value, EVTargetVoltage, as a function of said difference value between the acquired charge voltage, EVSEPresentVoltage, at the current instant t, and the setpoint voltage, EVTargetVoltage, and in that said method resumes at the first step with said modified setpoint voltage value, EVTargetVoltagenew ,.

7. Control method (1) according to claim 6, characterized in that said modified setpoint voltage value, EVTargetVoltagenew, is equal to said acquired setpoint value, EVTargetVoltage, to which is added the difference between the setpoint voltage, EVTargetVoltage, at the previous iteration and the acquired charge voltage, EVSEPresentVoltage, at the current time, t.

8. A control method (1) according to any one of claims 1 to 7, characterized in that when the method (1) is repeated for a continuous period of time, for example between 30 seconds and 1 minute, because 'during the first verification step (11) it is evaluated negatively that the acquired charge voltage value, EVSEPresentVoltage, is stabilized, then an alternating verification step is implemented, during which it is evaluated whether the difference in absolute value between the load voltage, EVSEPresentVoltage, at the current instant t, and the setpoint voltage, EVTargetVoltage, is between the first voltage threshold and the second voltage threshold, so that the the step of controlling the closing of the relays independently of the two evaluation steps (11, 12).

9. Device for controlling the electromagnetic relays (25) of an electric or hybrid motor vehicle (20) comprising an electric accumulator battery (26) defining a setpoint voltage, EVTargetVoltage, said motor vehicle being intended to be connected to a electric charging station (21) delivering a charging voltage, EVSEPresentVoltage, adapted to implement the method according to any one of claims 1 to

8.

10. Electric or hybrid motor vehicle (20) comprising an electric accumulator battery (26) defining a setpoint voltage, EVTargetVoltage, said motor vehicle further comprising relays. electromagnetic (25) and being configured to be connected to an electric charging station (21) delivering a charging voltage, EVSEPresentVoltage, said vehicle comprising a control device for the electromagnetic relays (25) according to claim 9.