Method for controlling the temperature of at least one capacitor suitable for an embedded charger

Abstract

The invention relates to a method for optimizing the lifespan of at least one capacitor of a capacitor module (400) of an electronic device (100), the electronic device (100) being suitable for charging a high-voltage battery (600) of an electric vehicle, the device comprising a power-factor-correction circuit (300), a DC / DC converter (500), a cooling device (700) suitable for cooling at least one capacitor of the capacitor module (400), and a second temperature sensor (910) placed on at least one capacitor of the capacitor module (400) and suitable for measuring an actual temperature of the at least one capacitor, the method comprising the following steps: • a first step a1) of activating the charger (100) with a view to charging the high-voltage battery (600), • a second step a2) of charging the high-voltage battery (600) using the charger (100) with a first setpoint power (P1_cons), and • a third step a3) of waiting a first determined time (tp1) during which the first setpoint power (P1_cons) is delivered to the battery (600).

Description

Method for controlling the temperature of at least one capacity suitable for an on-board charger. DESCRIPTION [Technical field]

[0001] The invention relates to the field of electric vehicles and more specifically to a method for controlling the temperature of at least one capacity suitable for an on-board charger of an electric vehicle. [State of the prior art]

[0002] An electric vehicle comprises at least one high-voltage battery, for example a 400-volt or 800-volt battery, coupled to a high-voltage electrical network (internal network of the electric vehicle) and a low-voltage battery, for example 12 volts, coupled to a low-voltage electrical network (internal network of the electric vehicle). The high-voltage battery and the low-voltage battery are adapted to deliver electrical energy and to store electrical energy respectively on the high-voltage electrical network and on the low-voltage electrical network.

[0003] To do this, the electric vehicle includes an on-board charger, better known as an OBC for "On Board Charger" in English, connected to the high-voltage battery called "BHT" via the high-voltage electrical network. The on-board charger is suitable for, once connected to a power supply network, converting the alternating voltage supplied by an external electrical network into a high-voltage direct voltage capable of recharging the high-voltage battery.

[0004] Figure 1 represents a schematic diagram of a state-of-the-art on-board electric charger 10 adapted to charge the high-voltage battery 60 dedicated, for example, to the power supply of an electric machine for the propulsion of an electric or hybrid vehicle.

[0005] The on-board electrical charger 10 comprises an electromagnetic filtering circuit 20, and a power factor correction circuit 30 called “PFC” which can be bidirectional. Said power factor correction circuit 30 further comprises an AC-DC converter circuit adapted to receive, for example, an electric current from a domestic AC power supply network.

[0006] The on-board electric charger 10 also comprises a capacity module 40 arranged between the power factor correction circuit 30 and a direct-direct DC / DC converter 50 adapted to charge the high voltage battery 60.

[0007] As is known to those skilled in the art, the charging of the low voltage power supply battery, not shown in FIG. 1, is carried out by the high voltage battery 60, by a second DC-DC converter, not shown in FIG. 1 connected between the high voltage battery 60 and the low voltage power supply battery.

[0008] The high voltage battery is charged using the on-board electric charger 10 once coupled to the electrical network 70.

[0009] The capacitor module 40 is composed of a determined number of electrochemical capacitors whose equivalent value is relatively large to accept a relatively large effective current value when charging the battery and to reduce, or sufficiently filter the ripples of the rectified voltage at the output of the power factor correction circuit 30 so that said ripples, once filtered, are compatible with the input characteristics of the DC / DC converter 50.

[0010] A solution well known to those skilled in the art for producing the capacitor module 40 is to implement a relatively large number of capacitors to obtain a large equivalent capacity value to be able to both control the ripples and accept large effective currents (or RMS currents for "Root Mean Square" in English) when charging the high voltage battery at full power.

[0011] A disadvantage of this solution is the need to increase the surface area of the printed circuit board or PCB to accommodate said capacities, significantly increasing the cost of the on-board charger 10.

[0012] Furthermore, the effective current value and more precisely the maximum effective current value depends on the battery charge level and the charger power. For example, an on-board charger may have a nominal power of 7KW.

[0013] Thus, depending on said maximum value of the effective current passing through said capacitors of the capacitor module 40, the latter heat up and can sometimes reach temperatures equal to or greater than a critical capacitor threshold temperature Tcritcap which is given by the capacitor manufacturer.

[0014] For example, the critical capacity threshold temperature Tcritcap is 85°C. Thus, in the case where, during charging of the high voltage battery by the charger, the temperature of the capacities reaches or exceeds the critical capacity threshold temperature Tcritcap then the lifespan of said capacities is reduced compared to use of said capacities at temperatures below the critical capacity threshold temperature Tcritcap.

[0015] To limit the temperature increase of the capacitors of the capacitor module 40, it is common to use a cooling device arranged for example on said capacitor module 40. The cooling device is suitable for cooling the capacitors through the capacitor module 40, but also for cooling electronic components arranged on the printed circuit of the on-board charger 10. Such a solution can use air cooling. However, since the quantities of calories to be evacuated are relatively large, the cooling device can also be based on a principle of cooling by a liquid, i.e. water or glycol. Thus, it is possible to improve the elimination of the calories generated by the electronic components and the capacitors.

[0016] As mentioned above, it is necessary to check the lifespan of the capacities of the on-board charger 10 because the latter is given for a minimum duration of use by the vehicle manufacturer, for example 20,000 hours, under conventional usage and recharging conditions.

[0017] However, sometimes, said charger 10 and therefore the capacities of the capacity module 40 of said charger 10 are used in extreme conditions, for example when recharging the electric vehicle on a charging station in full sun in summer in a supermarket parking lot which causes abnormal heating of the capacities and therefore overheating of said charger which can reduce its duration of use.

[0018] There is therefore a real need to ensure temperature control of the capacities to avoid exceeding the critical temperature in order to avoid premature deterioration of the said capacities. [Statement of the invention] The invention relates to a method for controlling the temperature of at least one capacitor to optimize the lifetime of at least one capacitor of a capacitor module of an electronic device, said electronic device being suitable for charging a high voltage battery of an electric vehicle, said device comprising a power factor correction circuit, a DC / DC direct-direct converter, a device for cooling adapted to cool at least one capacity of the capacity module, a second temperature sensor arranged on at least one capacity of the capacity module and adapted to measure an actual temperature of said at least one capacity, the method comprising the following steps: • a first step a1) consisting of activating the charger to charge the high voltage battery, • a second step a2), consisting of charging the high voltage battery using the charger with a first set power, • a third step a3) consisting of waiting for a first determined duration during which the first setpoint power is delivered to the battery, a fourth step a4) consisting of measuring, using the second temperature sensor, a first actual temperature of at least one capacity representative of the temperature of all the capacities of the capacity module, and comparing the first actual temperature to a first threshold value; in the case where the value of the first actual temperature is lower than the first threshold value then move to the second step a2), in the case where the value of the first actual temperature is higher than the first threshold value then move to a fifth step a5), • the fifth step a5), consisting of providing the battery with a second setpoint power equal to a percentage of the value of the first setpoint power, • a sixth step a6) consisting of waiting for a second determined duration during which the charger delivers the second set power to the battery, • a seventh step a7) consisting of measuring, using the second temperature sensor, a second actual temperature of at least one capacity representative of the temperature of all the capacities of the capacity module, and comparing the second actual temperature to a second threshold value; in the case where the value of the second actual temperature is lower than the second threshold value, then move on to the fourth step a4), and in the case where the value of the second actual temperature is higher than the second threshold value, then move on to an eighth step a8), • the eighth step a8) consisting of providing the battery with a third setpoint power equal to a percentage of the value of the first setpoint power, • the ninth step a9) consisting of waiting for a third determined duration during which the charger delivers the third set power to the battery, • the tenth step a10) consisting of measuring, using the second temperature sensor, a third actual temperature of at least one capacity representative of the temperature of all the capacities of the capacity module, and comparing the third actual temperature to a third threshold value; in the case where the value of the third actual temperature is lower than the third threshold value, then move on to an eleventh step a11), and in the case where the value of the third threshold value is higher than the third threshold value, then move on to a twelfth step a12), • the eleventh step a11) consisting of, in the case where the value of the third actual temperature is lower than a fourth threshold value Tseuil_4, moving to the fifth step a5) and, in the case where the value of the third actual temperature is higher than the value of the fourth threshold value, then moving to the eighth step a8), • the twelfth step a12) consisting of delivering to the battery (600) a fourth setpoint power equal to 0W, • the thirteenth step a13) consisting of measuring, using the second temperature sensor, a fifth actual temperature of at least one capacity representative of the temperature of all the capacities of the capacity module, and comparing the fifth actual temperature to a fifth threshold value; in the case where the value of the fifth actual temperature is greater than the fifth threshold value, then move on to the twelfth step a12), in the case where the value of the fifth actual temperature is less than the fifth threshold value, move on to a second step a2).

[0019] In an exemplary embodiment, the first setpoint power has a value of 11 KW.

[0020] In an exemplary embodiment, the first setpoint power has a value of 7KW.

[0021] For example, the first threshold value has a value of 75°C.

[0022] In another example, the second threshold value has a value of 85°C. [Description of the drawings] Other characteristics 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 appended drawings in which:

[0023] Figure 1 is a structural illustration of a prior art charger,

[0024] Figure 2 shows a structural diagram of the charger according to the invention,

[0025] Figure 3 is an illustration of the method according to the invention. [Description of embodiments]

[0026] The invention will be presented in the case of an implementation in an electric vehicle comprising at least one electrical machine capable of converting electrical energy into mechanical energy in order to drive at least one wheel of the electric vehicle in rotation.

[0027] With reference to Figure 2, there is shown a block diagram of an on-board electric charger 100 according to the invention. Said on-board electric charger 100 is adapted to charge the high voltage battery 600 dedicated for example to the power supply of a three-phase machine for the propulsion of an electric or hybrid vehicle.

[0028] The 100 on-board electric charger can be unidirectional or bidirectional.

[0029] The latter comprises an electromagnetic filtering circuit 200 and a power factor correction circuit 300 called “PFC” which can be bidirectional, said power factor correction circuit 300 comprising an AC-DC converter circuit adapted to receive an electric current from a domestic AC power supply network for example.

[0030] A capacity module 400 arranged between the power factor correction circuit 300 and a DC / DC converter 500 adapted to charge the high voltage battery 600. The capacity module 400 is also called by those skilled in the art “DC LINK” module.

[0031] As is known to those skilled in the art, the charging of the low voltage power supply battery, not shown in FIG. 2, is carried out by the high voltage battery 600, by a second DC-DC converter connected between the high voltage battery 600 and the low voltage power supply battery.

[0032] The high voltage battery is charged using the on-board electric charger 100 once coupled to the electrical network.

[0033] Cleverly, the capacitor module 400 is composed of a determined number of capacitors, for example electrochemical capacitors, adapted to accept a relatively high effective current value when charging the battery and to sufficiently filter the ripples of the rectified voltage at the output of the power factor correction circuit 300 so that said ripples, once filtered, are compatible with the input characteristics of the DC / DC converter 500. Cleverly, the device of the invention proposes to control an actual temperature of at least one capacitor called Trelcap.

[0034] The on-board charger 100 cleverly comprises a cooling device 800 arranged for example on the capacity module 400 but also on the power factor correction circuit 300 and on the DC / DC converter 500. The cooling device 800 comprises for example at least one pipe adapted to allow a cooling liquid to circulate. The cooling liquid is adapted to absorb calories originating from the heating of the electronic components of the power factor correction circuit 300 and the DC / DC converter 500 but also adapted to absorb the calories generated by the capacities of the capacity module 400. The mechanical fixing and the thermal coupling between the different elements are obvious to those skilled in the art.

[0035] Advantageously, a first temperature sensor 900 is arranged at the level of the pipe of the cooling device 800 allowing measurements of the temperature of the coolant Tliq. In a variant, the temperature of the liquid is given by measuring means arranged on the cooling circuit of the electric vehicle.

[0036] Advantageously, a second temperature sensor 910 is arranged on at least one capacitor of the capacitor module 400. Alternatively, the second temperature sensor 910 is arranged on packaging of the capacitor module 400. The second temperature sensor 910 is adapted to measure the actual Trelcap temperature of at least one capacitor representative of the temperature of all the capacitors of the capacitor module 400. Thus, thanks to the device of the invention, it is possible to know the temperature in real time of the capacitor module 400 and, depending on this, to activate or not the on-board charger 100.

[0037] The first temperature sensor 900 and the second temperature sensor 910 may use thermistor technology or alternatively semiconductor technology.

[0038] The invention proposes a method for controlling the temperature of at least one capacity of a capacity module 400 of an on-board charger 100.

[0039] To do this, the method of the invention comprises and as illustrated in FIG. 3 in the case where the electric vehicle is coupled to an external voltage outlet and recharging of the high voltage battery 600 is necessary, a first step a1) consisting of activating the charger 100 to charge the high voltage battery 600.

[0040] In a second step a2), the high-voltage battery 600 is charged by the charger 100 with a first setpoint power P1_cons. For example, the first setpoint power P1_cons is that determined by the vehicle manufacturer in the case of optimal charging of the battery 600. For example, in the case of an 11 kW charger, the first setpoint power P1_cons has a value of 11 kW.

[0041] The method then proposes a third step a3) consisting of waiting for a first determined duration tp1 during which the first setpoint power P1_cons is delivered to the battery 600. In an exemplary embodiment, the first determined duration tp 1 has a value of one minute.

[0042] The method proposes, after the elapse of the time of the first determined duration tp 1, the transition to a fourth step a4).

[0043] The fourth step a4) consists of measuring, using the second temperature sensor 910, a first actual temperature Trelcap_1 of at least one capacity representative of the temperature of all the capacities of the capacity module 400. The method also proposes, during this fourth step a4), to compare the first actual temperature Trelcap_1 with a first threshold value Tseuil_1. For example, the value of the first threshold value Tseuil_1 is equal to 75°C. Alternatively, the first actual temperature Trelcap_1 is an average of n temperature measurements from the second temperature sensor 910.

[0044] In the case where the value of the first actual temperature T relcap_1 is lower than the first threshold value T seu il_ 1 , the method proposes to move to the second step a2). In the case where the value of the first actual temperature Trelcap_1 is higher than the first threshold value Tseuil_1 , the method proposes to move to a fifth step a5).

[0045] During the fifth step a5), the method of the invention proposes that the on-board charger 100 delivers to the battery 600 a second setpoint power P2_cons equal to half the value of the first setpoint power P1_cons. It is easy for the person skilled in the art to control the charger 100 and its components to decrease and thus obtain such power. Then, the method proposes moving to a sixth step a6).

[0046] The sixth step a6) consists of waiting for a second determined duration tp2 during which the charger 100 delivers the second setpoint power P2_cons to the battery 100. In an exemplary embodiment, the second determined duration tp2 has a value of one minute. The method proposes, after the second determined duration tp2 has passed, the transition to a seventh step a7).

[0047] The seventh step a7) consists of measuring, using the second temperature sensor 910, a second actual temperature Trelcap_2 of at least one capacity representative of the temperature of all the capacities of the capacity module 400. The method also proposes, during this seventh step a7), to compare the second actual temperature Trelcap_2 with a second threshold value Tseuil_2. For example, the value of the second threshold value Tseuil_2 is equal to 80°C. Alternatively, the second actual temperature Trelcap_2 is an average of n temperature measurements from the second temperature sensor 910.

[0048] In the case where the value of the second actual temperature T relcap_2 is lower than the second threshold value Tseuil_2, the method proposes to move to the fourth step a4). In the case where the value of the second actual temperature Trelcap_2 is higher than the second threshold value Tseuil_2, the method proposes to move to an eighth step a8).

[0049] During the eighth step a8), the method of the invention proposes that the on-board charger 100 delivers to the battery 600 a third setpoint power P3_cons equal to a quarter of the value of the first setpoint power P1_cons. It is easy for those skilled in the art to control the charger 100 and its components to decrease and thus obtain such a power. Then, the method proposes moving to a ninth step a9).

[0050] In the ninth step a9) the method of the invention consists of waiting for a third determined duration tp3 during which the charger 100 delivers the third setpoint power P3_cons to the battery 100. In an exemplary embodiment, the third determined duration tp3 has a value of one minute. The method proposes, after the third determined duration tp3 has elapsed, the transition to a tenth step a10).

[0051] The tenth step a10) consists of measuring, using the second temperature sensor 910, a third actual temperature Trelcap_3 of at least one capacity representative of the temperature of all the capacities of the capacity module 400. The method also proposes, during this tenth step a10), to compare the third actual temperature Trelcap_3 with a third threshold value Tseuil_3. For example, the value of the third threshold value Tseuil_3 is equal to 85°C. Alternatively, the third actual temperature Trelcap_3 is an average of n temperature measurements from the second temperature sensor 910.

[0052] In the case where the value of the third actual temperature T relcap_3 is lower than the third threshold value Tseuil_3, the method proposes to move to an eleventh step a11). In the case where the value of the third actual temperature Trelcap_3 is higher than the third threshold value Tseuil_3, the method proposes to move to a twelfth step a12).

[0053] In the eleventh step a11) in the case where the value of the third actual temperature Trelcap_3 is lower than a fourth threshold value Tseuil_4, which is, for example, 75°C, the method proposes to move to the fifth step a5) and in the case where the value of the third actual temperature Trelcap_3 is higher than the value of the fourth threshold value Tseuil_4 then the method proposes to move to the eighth step a8).

[0054] During the twelfth step a12), the method of the invention proposes that the on-board charger 100 delivers to the battery 600 a fourth setpoint power P4_cons equal to 0W. It is easy for those skilled in the art to control the charger 100 and its components to decrease and thus obtain such power. Then, the method proposes moving to a thirteenth step a13).

[0055] The thirteenth step a13) consists of measuring, using the second temperature sensor 910, a fifth actual temperature Trelcap_5 of at least one capacity representative of the temperature of all the capacities of the capacity module 400. The method also proposes, during this thirteenth step a13), to compare the fifth actual temperature T relcap_5 with a fifth threshold value T threshold_5. For example, the value of the fifth threshold value T threshold_5 is equal to 75°C. Alternatively, the fifth actual temperature Trelcap_5 is an average of n temperature measurements from the second temperature sensor 910.

[0056] In the case where the value of the fifth actual temperature Trelcap_5 is greater than the fifth threshold value Tseuil_5, the process proposes the transition to the twelfth step a12). In the case where the value of the fifth actual temperature Trelcap_5 is lower than the fifth threshold value Tseuil_5, the method proposes moving to a second step a2).

[0057] Thus, thanks to the method of the invention and its modulation of the power setpoint time width, it is possible to regulate the power of the charger in stages allowing the battery to be charged optimally while ensuring control of the temperature of the capacities of the capacity module 400.

Claims

Claims

1. Method for optimizing the lifetime of at least one capacitor of a capacitor module (400) of an electronic device (100), said electronic device (100) being adapted to charge a high voltage battery (600) of an electric vehicle, said device comprising a power factor correction circuit (300), a DC / DC converter (500), a cooling device (700) adapted to cool at least one capacitor of the capacitor module (400), a second temperature sensor (910) arranged on at least one capacitor of the capacitor module (400) and adapted to measure an actual temperature of said at least one capacitor, the method comprising the following steps: • a first step a1) consisting of activating the charger (100) to charge the high voltage battery (600), • a second step a2), consisting of charging the high voltage battery (600) using the charger (100) with a first set power (P1_cons), • a third step a3) consisting of waiting for a first determined duration (tp1) during which the first set power (P1_cons) is delivered to the battery (600), • a fourth step a4) consisting of measuring, using the second temperature sensor (910), a first actual temperature (Trelcap_1) of at least one capacity representative of the temperature of all the capacities of the capacity module (400), and comparing the first actual temperature (Trelcap_1) to a first threshold value (Tseuil_1); in the case where the value of the first actual temperature (Trelcap_1) is lower than the first threshold value (Tseuil_1) then move to the second step a2), in the case where the value of the first actual temperature (Trelcap_1) is higher than the first threshold value (Tseuil_1) then move to a fifth step a5), • the fifth step a5), consisting of supplying the battery (600) with a second setpoint power (P2_cons) equal to half the value of the first setpoint power (P1_cons), • a sixth step a6) consisting of waiting for a second determined duration (tp2) during which the charger (100) delivers the second set power (P2_cons) to the battery (100), • a seventh step a7) consisting of measuring using the second temperature sensor (910) a second actual temperature (Trelcap_2) of at least one capacity representative of the temperature of all the capacities of the capacity module (400), and to compare the second actual temperature (Trelcap_2) to a second threshold value (Tseuil_2); in the case where the value of the second actual temperature (Trelcap_2) is lower than the second threshold value (Tseuil_2) then go to the fourth step a4), and in the case where the value of the second actual temperature (Trelcap_2) is higher than the second threshold value (Tseuil_2) then go to an eighth step a8), • the eighth step a8) consisting of supplying the battery (600) with a third setpoint power (P3_cons) equal to a quarter of the value of the first setpoint power (P1_cons), • the ninth step a9) consisting of waiting for a third determined duration (tp3) during which the charger (100) delivers the third set power (P3_cons) to the battery (100), • the tenth step a10) consisting of measuring, using the second temperature sensor (910), a third actual temperature (Trelcap_3) of at least one capacity representative of the temperature of all the capacities of the capacity module (400), and comparing the third actual temperature Trelcap_3) to a third threshold value (Tseuil_3); in the case where the value of the third actual temperature (Trelcap_3) is lower than the third threshold value (Tseuil_3) then moving to an eleventh step a11), and in the case where the value of the third threshold value (Tseuil_3) is higher than the third threshold value (Tseuil_3) then moving to a twelfth step a12), • the eleventh step a11) consisting of, in the case where the value of the third actual temperature (Trelcap_3) is lower than a fourth threshold value Tseuil_4, moving to the fifth step a5) and, in the case where the value of the third actual temperature (Trelcap_3) is higher than the value of the fourth threshold value (Tseuil_4) then moving to the eighth step a8). • the twelfth step a12) consisting of delivering to the battery (600) a fourth setpoint power (P4_cons) equal to 0W, • the thirteenth step a13) consisting of measuring, using the second temperature sensor (910), a fifth actual temperature (Trelcap_5) of at least one capacity representative of the temperature of all the capacities of the capacity module (400), and comparing the fifth actual temperature (Trelcap_5) to a fifth threshold value (Tseuil_5); in the case where the value of the fifth actual temperature (Trelcap_5) is greater than the fifth threshold value (Tseuil_5) then move on to the twelfth step a12), in the case where the value of the fifth actual temperature (Trelcap_5) is lower than the fifth threshold value (Tseuil_5) go to a second step a2).

2. Method for optimizing the lifetime of at least one capacitor of a capacitor module (400) of an electronic device (100) according to claim 1, characterized in that the first setpoint power (P1_cons) has a value of 11 KW.

3. Method for optimizing the lifetime of at least one capacitor of a capacitor module (400) of an electronic device (100) according to claim 1, characterized in that the first setpoint power (P1_cons) has a value of 7KW.

4. Method for optimizing the lifetime of at least one capacitor of a capacitor module (400) of an electronic device (100) according to any one of claims 1 to 3, characterized in that the first threshold value (Tseuil_1) has a value of 75°C.

5. Method for optimizing the lifetime of at least one capacitor of a capacitor module (400) of an electronic device (100) according to any one of claims 1 to 4, characterized in that the second threshold value (Tseuil_2) has a value of 85°C.

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