阅读说明：本技术 在混合牵引网络中控制激活对电机进行电气控制的方法 (Method for controlling the activation of an electric machine in a hybrid traction network ) 是由 D·维迪尔 J·拉柴泽 于 2020-03-13 设计创作，主要内容包括：本发明的主题是用于在机动车辆的电气网络中在所述车辆的牵引网络(3)中存在牵引电池组(1)故障之后控制激活对电机(4)进行电压控制的控制方法。牵引网络包括牵引电池组(1)、电机(4)、换流器(5)和将牵引电池组(1)连接到所述机动车辆的车载网络(2)的DCDC直流转换器(9)。该方法包括对存在于电气网络中的电容进行预充电的步骤和激活电机(4)的电气网络的电压控制的步骤。在停用预充电之前激活电机(4)处于电压控制的激活。(The subject of the invention is a control method for controlling the activation of the voltage control of an electric machine (4) in the electrical network of a motor vehicle after a traction battery (1) failure in the traction network (3) of said vehicle. The traction network comprises a traction battery (1), an electric machine (4), an inverter (5) and a DCDC direct current converter (9) connecting the traction battery (1) to the on-board network (2) of said motor vehicle. The method comprises a step of pre-charging a capacitance present in the electrical network and a step of activating a voltage control of the electrical network of the electrical machine (4). The activation motor (4) is in voltage-controlled activation before the deactivation of the pre-charging.)

1. Control method for controlling the activation of the voltage control of an electric machine (4) after a traction battery (1) fault in the traction network (3) of a motor vehicle in the electrical network of said vehicle, the traction network (3) comprising the traction battery (1), the electric machine (4), an inverter (5) and a DC/DC direct current converter (9) connecting the traction battery to the on-board network (2) of said motor vehicle, the method comprising:

a first step of pre-charging a capacitance present in the electrical network by means of a pre-charging device,

-a second step of activating a voltage control of the electric machine (4) when the voltage of the electric network reaches a predetermined threshold value, the electric machine (4) providing a current with a setting voltage, the setting voltage corresponding to an initial setting equal to the voltage of the electric network,

-a third step of gradually increasing the setting voltage to reach a target voltage value of the electrical network,

-a fourth step of deactivating the pre-charging according to the voltage of the electrical network.

2. Method according to claim 1, characterized in that the predetermined threshold value of the voltage of the electrical network corresponds to a voltage value comprised in a range of voltage values in which the electric machine (4) can be operated under voltage control.

3. Method according to claim 1 or 2, characterized in that the pre-charging means is embodied as a traction battery (1).

4. A method according to claim 3, characterized in that the fourth step of deactivating the pre-charging is performed when the voltage of the electrical network is greater than the target voltage value of the electrical network.

5. Method according to claim 4, characterized in that the target voltage of the electrical network corresponds to the voltage value of the electrical network for which the traction battery pack (1) is charged.

6. Method according to claim 1 or 2, characterized in that the pre-charging means is embodied as a DC/DC direct-current converter (9).

7. The method according to claim 6, characterized in that the fourth step of deactivating the pre-charging is performed when the voltage value of the electrical network is equal to the target electrical network voltage value.

8. Electrical network in a hybrid or electric vehicle, comprising a traction battery pack (1), the traction battery pack (1) feeding a traction network (3) equipped with an inverter (5) and a traction motor (4) and an on-board network (2) connected to the traction network (3) through a DC/DC direct-current converter (9), the motor (4), the converter (9), the traction battery pack (1) and the inverter (5) being operated by an electronic control unit present in the on-board network, characterized in that the electronic control unit (10) comprises means for implementing a control method according to any one of the preceding claims.

Technical Field

The invention relates to a method for controlling the activation of the voltage control of an electric machine in a traction network of an electric or hybrid vehicle.

Background

The electrical portion of an electric or hybrid vehicle typically includes a traction battery pack that enables feeding of the traction network and the on-board network.

The traction network includes traction motors for propelling the vehicle, and the traction motors are fed with high voltage current provided by a traction battery pack. An inverter may be interposed between the traction battery pack and the electric machine.

The traction battery packs also feed the on-board network, which requires a generally low-voltage or medium-voltage feed. Therefore, a DC/DC converter or a DC-DC converter with a lower voltage is inserted between the traction battery pack and the on-board network in order to convert the high-voltage current into a low-voltage or medium-voltage current.

The on-board network also comprises consumer elements, in particular devices enabling the management of the motor vehicle, such as electronic control units. The control unit is mounted on the vehicle to operate or control various control members. There are also multimedia devices, electric actuators or lighting sources in the vehicle network. In the event of a failure of the traction battery pack, the traction network may operate with the contactors of the traction battery pack open. The motor is then placed in a voltage control mode and becomes a current generator to regulate the voltage of the electrical network.

In order to control the placing of the electric machine in voltage control, the capacitance of the vehicle electrical network must be pre-charged. This makes it possible to secure the voltage operating range of the motor and the DC/DC converter. Thus, it is known to pre-charge the capacitor via the traction battery pack or DC/DC. The pre-charging is stopped when the voltage of the electrical network reaches a predetermined target voltage. The contactors of the traction battery pack remain open and components in the network, in particular the voltage control of the electric machine, are activated in parallel.

However, this known sequence of guiding the activation of the voltage control of the motor is not very robust, since the pre-charge may fail halfway. In fact, in a voltage control configuration with the contactors open, the equivalent capacitance of the network is limited. In particular, any current draw caused by the activation of the electric machine or the DC/DC can lead to a voltage dip of the electrical network and thus to a discharge of the previously precharged network capacitance.

The object of the present invention is to propose a reliable and robust method for controlling the activation of the voltage control of an electric machine over an electrical network.

Disclosure of Invention

The invention relates to a control method for controlling the activation of the voltage control of an electric machine after a traction battery failure in the traction network of a motor vehicle in the electrical network of said vehicle, the traction network comprising the traction battery, the electric machine, an inverter and a DC/DC direct-current converter connecting the traction battery to the on-board network of said motor vehicle, the method comprising:

a first step of pre-charging a capacitance present in the electrical network by means of a pre-charging device,

-a second step of activating a voltage control of the electrical machine when the voltage of the electrical network reaches a predetermined threshold value, the electrical machine providing a current with a setting voltage corresponding to an initial setting equal to the voltage of the electrical network,

-a third step of gradually increasing the setting voltage to reach a target voltage value of the electrical network,

-a fourth step of deactivating the pre-charging according to the voltage of the electrical network.

According to one embodiment of the invention, the predetermined threshold value of the voltage of the electrical network corresponds to a voltage value comprised in a range of voltage values in which the electric machine is operable under voltage control.

According to another embodiment of the invention, the pre-charging device is embodied as a traction battery pack.

Advantageously, the fourth step of deactivating the pre-charge is performed when the voltage of the electrical network is greater than a target voltage value of the electrical network.

Still advantageously, the target voltage of the electrical network corresponds to the voltage value of the electrical network for which the traction battery pack is charging.

According to a further embodiment of the invention, the pre-charging device is embodied as a DC/DC direct current converter.

Advantageously, the fourth step of deactivating the pre-charge is performed when the voltage value of the electrical network is equal to the target electrical network voltage value.

The invention also relates to an electrical network in a hybrid or electric vehicle, the electrical network comprising a traction battery pack (1), the traction battery pack (1) feeding a traction network (3) equipped with an inverter (5) and a traction motor (4) and an on-board network (2) connected to the traction network (3) by a DC/DC direct current converter (9), the motor (4), the converter (9), the traction battery pack (1) and the inverter (5) being operated by an electronic control unit present in the on-board network, characterized in that the electronic control unit (10) comprises means for implementing a control method according to any one of the preceding claims.

One advantage of the present invention resides in accurate and reliable control of the activation of an electric network voltage controlled motor.

Another advantage of the present invention resides in the reliability of the method.

Yet another advantage of the present invention is that it reduces electrical network voltage dips when activating voltage control of the electric machine.

Another advantage of the invention is that efficient operation of the motor under voltage control is ensured.

Drawings

Other characteristics, advantages and details of the invention will be better understood on reading the following supplementary description of an embodiment given by way of non-limiting example, in conjunction with the attached drawings, in which:

figure 1 shows an electrical network in a hybrid or electric vehicle,

FIG. 2 shows a schematic diagram of a method according to an embodiment of the invention, in which the traction battery pack is used as a pre-charging device, and

fig. 3 shows a schematic diagram of a method according to an embodiment of the invention, wherein a DCDC converter is used as a pre-charging device.

Detailed Description

Fig. 1 shows an electrical network in a hybrid or electric vehicle. The electrical network comprises a traction battery 1, which traction battery 1 feeds a high voltage traction network 3 equipped with an inverter 5 and a traction motor 4.

The traction battery 1 comprises a pre-charging branch 6a, which is branched from a positive branch 6b, the positive branch 6b connecting the positive pole + of the traction battery 1 to the positive branch of the traction network 3 and to the positive pole + of the capacitance present in the electrical network. The negative branch 6c connects the negative pole of the traction battery 1 to the negative branch of the traction network 3. All branches 6a to 6c of the traction battery 1 are provided with contactors 7, and the pre-charging branch 6a comprises a resistor 8. The resistor 8 enables the charging current to be limited.

Pre-charging systems are known to those skilled in the art and are typically placed in parallel or shunt with the main contactors of the battery pack. This system makes it possible to ensure that one or more input capacitances of a device connected to the battery pack are charged before the charging system itself takes over.

In this way, when the traction battery pack 1 precharges the capacitance of the electrical network, the contactors 7 of the positive branch 6b and the negative branch 6c remain open while the contactors 7 of the precharge branch 6a remain closed.

The low or medium voltage on-board network 2 is connected to the traction network and the traction battery pack via a DC/DC converter 9. The DC/DC converter 9 is arranged in shunt with the electric machine 4 of the traction network 3. The on-board network 2 at the output of the converter 9 comprises a number of consumer devices, in particular an electronic control unit 10.

The electronic control unit 10 ensures the management functions of the electrical network, in particular the operation of the traction battery 1, the inverter 5, the electric machine 4 and the DC/DC converter 8.

Thus, the control method according to the invention for controlling activation of voltage control of an electric machine in a hybrid traction network may be implemented in an electrical network as described above, but it is not limited to this particular type of electrical network.

The method according to the invention enables an effective control of placing the electric machine 4 in voltage control in case of a failure of the traction battery 1.

A failure of the traction battery 1 may occur for a number of reasons and under these conditions, the traction battery 1 is isolated from the electrical network for safety reasons. For this purpose, the contactor 7 remains open, so that it is necessary to maintain the current in the electrical network and to enable the devices of the electrical network to operate. The motor 4 then ensures the function of a current generator for controlling the voltage of the electrical network, which is referred to as putting the motor 4 in the voltage control mode of the electrical network.

In order to guarantee the voltage operating range of the DC/DC converter 9 and the motor 4, the capacitors of the electrical network need to be pre-charged. The pre-charging is performed by means of a pre-charging device, which may be the traction battery 1 or the DC/DC converter 9 via the pre-charging branch 6 a. The pre-charging also enables a predetermined voltage value of the electrical network to be reached. Advantageously, the predetermined voltage value is a voltage value at which the motor 4 can operate under voltage control. The voltage operating range varies depending on the type of motor, and is typically between 36V and 900V, preferably 36V and 54V, 265V and 450V, or 530V and 900V.

Depending on the electric machine (4) used, the traction battery pack (1) and the DCDC converter (9) are adjusted accordingly.

According to a second step of the method according to the invention, the electric machine 4 is activated in voltage control when the voltage across the electric network reaches a predetermined threshold. The predetermined voltage threshold depends in particular on the minimum value of the voltage operating range of the electric machine 4 used in the electrical network.

The electric machine 4 then becomes a generator which supplies current to the entire electrical network with a setting voltage equal to the voltage of the electrical network. In this step of the method, when the active machine 4 is in voltage control, the setting voltage applied to the machine is equal to the voltage of the electrical network. Thus, the initial setting value is called. This step makes it possible to activate the electric machine 4 in a safe manner, while avoiding electrical network voltage dips that may occur during activation. In fact, during its activation, the motor 4 may cause a current draw, which may evacuate the pre-charged capacitor. The fact that the pre-charging is always active enables the activation of the motor 4 to be supported, avoiding any voltage dip.

According to a third step of the method, the setting voltage applied to the motor 4 is gradually increased towards a target voltage value that is greater than the initial setting value. A first advantage of this step is to ensure that the motor 4 operates under voltage control. Finally, this step enables a gradual increase of the voltage value of the electrical network to ensure a gradual start-up of the electrical network devices. According to a fourth step of the method, the pre-charging of the capacitance of the electrical network is stopped. The pre-charging is stopped when the electric machine 4 supplies the current required for the activation and operation of the various devices of the electrical network. In this way, the pre-charging is stopped when the voltage of the electrical network reaches the target voltage value. This target voltage value depends inter alia on the type of electric machine 4 used and also on the pre-charging arrangement used. Depending on the pre-charging device used, the target voltage value that the motor 4 no longer needs to support by the pre-charging device is different.

The basic principle of the invention is based on the fact that the pre-charging remains active during the voltage control of the active motor 4. This is so that the electrical network is not collapsed when the motor 4 is activated, which would normally be the case if the pre-charge were deactivated before the motor 4 was activated. Furthermore, the third step of gradually increasing the setting voltage towards a target voltage greater than the initial setting voltage makes it possible to limit or even eliminate voltage dips that may occur in the electrical network, which may occur when other devices in the electrical network are activated. This step also makes it possible to ensure that the motor 4 operates in voltage control mode.

FIG. 2 is a schematic diagram illustrating steps of a method according to one embodiment of the invention. In this embodiment, the pre-charging of the electrical network capacitance is performed by the traction battery pack 1. In this embodiment, only the contactor 7 of the pre-charging branch 6a is closed.

The traction battery 1 is then configured, for example by the electronic control unit 10, to deliver current to the electrical network. Once the voltage of the electrical network reaches a predetermined threshold, the pre-charge voltage is said to be reached. The activation motor 4 is then in voltage control.

In this embodiment of the invention, the predetermined threshold corresponds to a voltage value of the traction battery pack.

The electric machine 4 is then configured, for example by the electronic control unit 10, to provide an electric current having a setting voltage corresponding to an initial setting value, which is equal to the voltage of the electric network.

And then gradually increasing the setting value to reach the target electrical network voltage value. In this embodiment shown in fig. 2, the pre-charging is deactivated when the voltage of the electrical network is greater than the value of the voltage provided by the traction battery 1. In this way, the target electrical network voltage value corresponds to the voltage value of the electrical network for which the traction battery pack is charging. In fact, as soon as the voltage generated by the electric machine 4 is greater than the voltage generated by the traction battery 1, the current in the pre-charging branch 6a of the traction battery 1 is reversed. The precharge must then be deactivated.

In this embodiment of the method depicted in fig. 2, the gradual increase of the setting voltage lasts for a predetermined period of time once the pre-charging is deactivated. When the voltage of the electrical network reaches the target electrical network voltage value within a predetermined time period, the devices of the electrical network are activated.

FIG. 3 is a schematic diagram illustrating steps of a method according to one embodiment of the invention. In this embodiment the pre-charging of the electrical network capacitance is performed by a DC/DC direct current converter 9. The DC/DC converter 9 is then configured to restore the current in the electrical network in order to pre-charge the capacitance. As soon as the voltage of the electrical network reaches a predetermined threshold, the electric machine 4 is activated in voltage control. Thus, is said to reach the precharge voltage.

According to this embodiment of the invention shown in fig. 3, the predetermined threshold value depends on the voltage operating range of the motor.

The electric machine 4 is then configured, for example by the electronic control unit 10, to provide an electric current having a setting voltage corresponding to an initial setting value, which is equal to the voltage of the electric network.

And then gradually increasing the setting value to reach the target electrical network voltage value. In this embodiment, the pre-charging is deactivated once the voltage of the electrical network reaches the target electrical network voltage value. In this embodiment of the invention, the target electrical network voltage value corresponds to a voltage value at which devices of the electrical network can be activated without collapsing the electrical network.

In this embodiment of the method depicted in fig. 3, the pre-charging is deactivated once the target electrical network voltage is reached. The devices of the electrical network are activated once the voltage of the electrical network reaches the target electrical network voltage value within a predetermined time period.