CN113715648A

CN113715648A - Vehicle charging system and vehicle

Info

Publication number: CN113715648A
Application number: CN202111199837.XA
Authority: CN
Inventors: 甘银华; 毕路
Original assignee: Weilai Automobile Technology Anhui Co Ltd
Current assignee: Weilai Automobile Technology Anhui Co Ltd; NIO Technology Anhui Co Ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2021-11-30

Abstract

The invention relates to the technical field of vehicles, in particular to a vehicle charging system and a vehicle, and aims to solve the problem of how to safely, conveniently and effectively use a charging facility for charging under the condition that the voltage grades of a power battery and the charging facility are not matched. The charging control device in the vehicle charging system can firstly control the power battery, the voltage conversion device, the power distribution device and the charging port capacitor to form a conducting loop to pre-charge the charging port capacitor and then charge the power battery when the voltage grades of the power battery and the charging facility are not matched, and can also directly control the power battery, the voltage conversion device, the power distribution device and the charging port capacitor to form a charging loop to charge the power battery when the voltage grades are matched. Based on the above embodiment, the charging facility can be safely and effectively used for charging under the condition that the voltage grades are not matched, the charging process is simplified under the condition that the voltage grades are matched, and the operation convenience of charging is improved.

Description

Vehicle charging system and vehicle

Technical Field

The invention relates to the technical field of vehicles, and particularly provides a vehicle charging system and a vehicle.

Background

With the rapid development of electric vehicle technology, the voltage level of high voltage systems in electric vehicles is also increasing, such as from 400V to 800V. However, the charging facility is limited by factors such as cost and the like, and cannot be upgraded and modified in time, so that the charging facility cannot adapt to rapid changes of the voltage level of the high-voltage system in the electric vehicle. In order to solve the problem, patent application publication No. CN112600411A discloses a voltage conversion device, which multiplexes an inverter and a motor winding in a power control unit PEU in an electric vehicle, realizes a boosting function from a second direct-current voltage, such as 400V, to a first direct-current voltage, such as 800V, and can convert a lower voltage provided by a charging facility into a higher voltage to charge a power battery, thereby taking into account charging facilities of different voltage classes on the market.

However, in practical applications, a charging port capacitor is disposed on a side of the electric vehicle connected to the charging facility, and the charging port capacitor needs to be precharged when the electric vehicle is charged, so as to prevent surge current from being generated when a charging relay of a high-voltage system in the electric vehicle is closed and damaging the charging relay. Meanwhile, the charging port capacitor also needs to be discharged at the end of charging so as to prevent the user from being shocked by the electric energy stored in the charging port capacitor when the user disconnects the electric vehicle from the charging facility, such as pulling the charging gun out of the electric vehicle. When the voltage conversion device disclosed in the above patent application is used to charge the power battery, if different methods are respectively adopted for the charging facilities with different voltage levels to perform the pre-charging and discharging of the charging port capacitor, not only the complexity of the operation of charging the power battery is increased, but also the charging fault is very easy to occur.

Disclosure of Invention

In order to overcome the above-mentioned drawbacks, the present invention is proposed to provide a vehicle charging system and a vehicle that solve or at least partially solve the technical problem of how to safely, conveniently and efficiently use a charging facility to charge a vehicle in the case where a power battery in the vehicle does not match the charging facility.

In a first aspect, the present invention provides a vehicle charging system, the vehicle comprising a power battery and an electric drive system, the electric drive system comprises an inverter and a motor, wherein the direct current side of the inverter is connected with the power battery, an alternating current side of the inverter is connected with a stator winding of the motor, the vehicle charging system includes a voltage conversion device, the voltage conversion device includes the inverter, the stator winding, a first positive terminal, a second positive terminal, and a negative terminal, the first positive electrode terminal and the negative electrode terminal are connected to the positive electrode and the negative electrode on the direct current side, respectively, the second positive terminal is connected with a center tap of the stator winding, the charging system further comprises a charging port, a charging port capacitor, a power distribution device and a charging control device, the power distribution equipment is respectively connected with the voltage conversion equipment and the charging port capacitor;

the charge control device is configured to:

responding to the received charging starting instruction, and judging whether the output voltage level of an external charging facility connected with the charging port is matched with the charging voltage level of the power battery or not;

if yes, directly controlling the power battery, the voltage conversion equipment, the power distribution equipment and the charging port to form a charging loop and controlling the external charging facility to charge the power battery through the charging loop;

if not, the power battery, the voltage conversion equipment, the power distribution equipment and the charging port capacitor are controlled to form a conduction loop, the power battery is controlled to pre-charge the charging port capacitor through the conduction loop, and after pre-charging is completed, the power battery, the voltage conversion equipment, the power distribution equipment and the charging port are controlled to form a charging loop and the external charging facility is controlled to charge the power battery through the charging loop.

In one aspect of the vehicle charging system described above, the charging port includes a positive input terminal and a negative input terminal;

the power distribution apparatus includes a first switch, a second switch, and a third switch, the first switch being a single pole double throw switch; a first fixed contact and a second fixed contact of the first switch are respectively connected with the first positive terminal and a second end of the second switch, a first end of the second switch is connected with a second positive terminal, a first end of a movable contact of the first switch is connected with the positive input terminal, and a first end and a second end of the third switch are respectively connected with the negative terminal and the negative input terminal;

and the first end and the second end of the charging port capacitor are respectively connected with the second end of the second switch and the first end of the third switch.

In one technical solution of the above vehicle charging system, the charging control device includes a charging start control module, and the charging start control module includes a capacitor pre-charging sub-module;

the capacitance pre-charge sub-module is configured to pre-charge the charging port capacitance by performing the following operations:

in response to a received charging starting instruction, closing the second switch and the third switch, and controlling a second end of a movable contact in the first switch to be connected with the second fixed contact, so that the power battery, the voltage conversion device, the second switch and the charging port capacitor form a conducting loop;

and controlling the voltage conversion equipment to reduce the voltage of the electric energy output by the power battery, transmitting the reduced voltage electric energy to the charging port capacitor through the conducting loop for pre-charging, and stopping pre-charging when the voltage of the charging port capacitor reaches a set value.

In one technical solution of the above vehicle charging system, the charging start control module further includes a first power battery charging submodule;

the first power battery charging submodule is configured to charge the power battery when the output voltage level of the external charging facility matches the charging voltage level of the power battery by performing the following operations:

and in response to a received charging starting instruction, closing the third switch and controlling the second end of the movable contact piece in the first switch to be connected with the first fixed contact, so that the power battery, the voltage conversion device, the power distribution device, the charging port and the external charging facility form a charging loop, and the external charging facility is controlled to charge the power battery through the charging loop.

In one technical solution of the above vehicle charging system, the charging start control module further includes a second power battery charging submodule;

the second power battery charging submodule is configured to charge the power battery when the output voltage level of the external charging facility does not match the charging voltage level of the power battery by performing the following operations:

after the capacitor pre-charging submodule stops pre-charging, a connection switch of the charging port and the external charging facility is closed, so that the power battery, the voltage conversion device, the power distribution device, the charging port and the external charging facility form a charging loop, and the external charging facility is controlled to charge the power battery through the charging loop.

In one aspect of the above vehicle charging system, the charging control apparatus includes a charging stop control module configured to discharge the charging port capacitance by performing:

in response to a received charging stop instruction, disconnecting the connecting switch, then disconnecting the third switch and controlling a touch piece in the first switch to be suspended, so that the voltage conversion device, the power distribution device and the charging port capacitor form a conducting loop, and the charging port capacitor is controlled to discharge through the conducting loop;

the charging stop instruction is an instruction for stopping charging the power battery and controlling the power battery to continue to supply power to the high-voltage system in the vehicle after the charging is stopped, or an instruction for stopping charging the power battery and controlling the power battery to stop supplying power to the high-voltage system in the vehicle after the charging is stopped.

In one aspect of the above vehicle charging system, the voltage conversion device further includes a discharge circuit connected in parallel to a dc side of the inverter, the discharge circuit includes a power electronic device and a resistor, a first main electrode of the power electronic device is connected to a positive electrode of the dc side, a second main electrode of the power electronic device is connected to a first end of the resistor, and a second end of the resistor is connected to a negative electrode of the dc side.

In one aspect of the above vehicle charging system, when the charge stop instruction is an instruction to stop charging a power battery and to control the power battery to no longer supply power to a high-voltage system in the vehicle after the stop of charging, the charge stop control submodule is further configured to discharge the charging port capacitor by performing:

and in response to a received charging stop instruction, disconnecting the connecting switch, then disconnecting the third switch, controlling a touch piece in the first switch to be suspended, disconnecting the connecting switch between the power battery and the inverter, and finally controlling the power electronic device to be switched on, so that the voltage conversion equipment, the power distribution equipment and the charging port capacitor form a conducting loop, and controlling the charging port capacitor to discharge through the conducting loop.

In a second aspect, a vehicle is provided, where the vehicle includes a power battery and an electric drive system, the electric drive system includes an inverter and an electric motor, a dc side of the inverter is connected to the power battery, and an ac side of the inverter is connected to a stator winding of the electric motor, and the vehicle further includes the vehicle charging system according to any one of the above aspects of the vehicle charging system.

One or more technical schemes of the invention at least have one or more of the following beneficial effects:

in an embodiment of the present invention, the vehicle charging system may include a charging port, a voltage conversion device, a charging port capacitor, a power distribution device, and a charging control device, where the power distribution device is connected to the voltage conversion device and the charging port capacitor, respectively.

The voltage conversion device may multiplex an electric drive system of the vehicle, which may include an inverter and a motor, a dc side of the inverter being connected to the power battery, and an ac side of the inverter being connected to the stator windings of the motor. The voltage conversion device may include the inverter and the stator winding, and may further include a first positive terminal, a second positive terminal, and a negative terminal, wherein the first positive terminal and the negative terminal are connected to a positive electrode and a negative electrode of a dc side in the inverter, respectively, and the second positive terminal is connected to a center tap of the stator winding. The first positive terminal, the second positive terminal, and the negative terminal constitute an external power input side of the voltage conversion device, and the direct current side of the inverter constitutes an external power output side of the voltage conversion device. When the output voltage level of the external power supply connected with the input side of the external power supply is matched with the power supply voltage level of the load connected with the output side of the external power supply, the output electric energy of the external power supply can be directly transmitted to the load; when the output voltage level of the external power supply is not matched with the power supply voltage level of the load, the voltage of the electric energy output by the external power supply can be converted, and then the electric energy after voltage conversion is transmitted to the load.

The charging control apparatus may be configured to control the power battery, the voltage conversion apparatus, the power distribution apparatus, and the charging port capacitor to form a conductive loop in response to a received charging start instruction or charging stop instruction when an output voltage level of an external charging facility connected to a charging port of the vehicle charging system does not match a charging voltage level of the power battery, and control the power battery to pre-charge the charging port capacitor via the conductive loop or control the charging port capacitor to discharge via the conductive loop. By precharging the charging port capacitor, it is possible to prevent inrush current from being generated to damage the charging switch when the charging switch of the high-voltage system in the vehicle is closed (for example, the connection switches Kpos + and Kneg "between the power battery 1 and the inverter shown in fig. 2 are closed). By discharging the charging port capacitor, the user is prevented from being shocked by the stored energy on this charging port capacitor when the vehicle is disconnected from the external power source (e.g., disconnecting the charging port from the external charging facility connection switches K4 and K5 as shown in fig. 2). Based on the above embodiment, not only can charging facilities with different voltage levels on the market be compatible with the voltage conversion equipment, but also the charging port capacitor can be precharged and discharged through a conducting loop formed by the charging control equipment, the power distribution equipment and the like, so that the charging facility can be safely and effectively used for charging the vehicle under the condition that the voltage levels of the vehicle and the charging facility are not matched.

Further, the charging control device may be configured to directly control the power battery, the voltage conversion device, the power distribution device, the charging port and the external charging facility to form a charging loop in response to the received charging start instruction when the output voltage level matches the charging voltage level, and control the external charging facility to charge the power battery via this charging loop. Based on the embodiment, when the output voltage level is matched with the charging voltage level, the capacitor of the charging port is not required to be pre-charged, the power battery, the voltage conversion equipment, the power distribution equipment, the charging port and an external charging facility can be directly controlled to form a charging loop of the power battery, the power battery is charged, the capacitor of the charging port is not required to be discharged after the charging is finished, the charging process of the power battery is simplified, and the operation convenience of charging the power battery is improved.

Drawings

The disclosure of the present invention will become more readily understood with reference to the accompanying drawings. As is readily understood by those skilled in the art: these drawings are for illustrative purposes only and are not intended to constitute a limitation on the scope of the present invention. Moreover, in the drawings, like numerals are used to indicate like parts, and in which:

FIG. 1 is a block diagram of the main structure of a vehicle charging system according to one embodiment of the invention;

fig. 2 is a schematic diagram of a main structure of a vehicle charging system according to another embodiment of the invention;

FIG. 3 is a schematic diagram of the state of the vehicle charging system of FIG. 2 when used to charge an 800V power battery using an 800V charging post, according to one embodiment of the present invention;

FIG. 4 is a schematic diagram of a state of the vehicle charging system of FIG. 2 when used to charge an 800V power battery using a 400V charging post, according to one embodiment of the present invention;

FIG. 5 is a schematic diagram of a vehicle charging system state when the vehicle charging system of FIG. 2 is employed and a 400V charging post is used to charge an 800V power battery, according to another embodiment of the present invention;

FIG. 6 is a flow chart illustrating the main steps of pre-charging a charge port capacitor according to one embodiment of the present invention;

FIG. 7 is a flow chart illustrating the main steps of discharging the charging port capacitor after the 800V power battery is charged by using the 400V charging pile according to an embodiment of the present invention;

list of reference numerals：

1: a power battery; 2: a voltage conversion device; 3: a power distribution apparatus; 4: a charging port; 21: a first positive terminal; 22: a second positive terminal; 23: a negative terminal; 41: a positive input terminal of the charging port; 42: and a negative input terminal of the charging port.

Detailed Description

Some embodiments of the invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.

In the description of the present invention, a "module" or "processor" may include hardware, software, or a combination of both. A module may comprise hardware circuitry, various suitable sensors, communication ports, memory, may comprise software components such as program code, or may be a combination of software and hardware. The processor may be a central processing unit, a microprocessor, a digital signal processor, or any other suitable processor. The processor has data and/or signal processing functionality. The processor may be implemented in software, hardware, or a combination thereof. Non-transitory computer readable storage media include any suitable medium that can store program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random-access memory, and the like. The term "a and/or B" denotes all possible combinations of a and B, such as a alone, B alone or a and B. The term "at least one A or B" or "at least one of A and B" means similar to "A and/or B" and may include only A, only B, or both A and B. The singular forms "a", "an" and "the" may include the plural forms as well.

The following explains the terms related to the present invention.

The power electronic device may be a fully-controlled power Semiconductor device, such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), an Integrated Gate Commutated Thyristor (IGCT), or the like. Meanwhile, all the fully-controlled power semiconductor devices are three-terminal devices, such as a MOSFET (metal-oxide-semiconductor field effect transistor) comprising a source electrode, a drain electrode and a gate electrode, an IGBT comprising a collector electrode, an emitter electrode and a gate electrode, and an IGCT comprising a collector electrode, an emitter electrode and a gate electrode. Wherein the source, drain, collector and emitter are main electrodes and the gate and gate are control electrodes. For clarity of description of the main electrodes of the power electronic device, the main electrodes in the power input direction of the power electronic device are described as first main electrodes (such as the drain of a MOSFET and the collector of an IGBT) and the main electrodes in the power output direction are described as second main electrodes (such as the source of a MOSFET and the emitter of an IGBT).

Referring to fig. 1, fig. 1 is a main structural block diagram of a vehicle charging system according to an embodiment of the present invention. In the embodiment of the invention, the vehicle can comprise a power battery and an electric drive system, the electric drive system can comprise an inverter and an electric motor, the direct current side of the inverter is connected with the power battery, the alternating current side of the inverter is connected with the stator winding of the electric motor, the inverter can convert the direct current output by the power battery into alternating current, and then the electric motor can operate under the control of the alternating current to provide power for driving the vehicle to run. As shown in fig. 1, the vehicle charging system in the embodiment of the invention may include a power battery 1, a voltage conversion device 2, a power distribution device 3, a charging port 4, and a charging control device (not shown in fig. 1), each of which is specifically described below.

A voltage conversion device 2

In an embodiment of the present invention, the voltage conversion device 2 may include an inverter and a stator winding of a motor in the electric drive system, wherein the three-phase stator windings of the motor are connected in a Y-connection manner and form a center tap. Furthermore, the voltage conversion device 2 may further include a first positive terminal 21, a second positive terminal 22, and a negative terminal 23, the first positive terminal 21 and the negative terminal 23 being connected to a positive pole and a negative pole on the direct current side, respectively, and the second positive terminal 22 being connected to a center tap of the stator winding.

Referring to fig. 2, the inverter may be a three-phase full-bridge type inverter including three-phase legs, each of which includes an upper leg and a lower leg, respectively. The upper bridge arm and the lower bridge arm of the first phase bridge arm respectively comprise power electronic devices Q1 and Q2, the upper bridge arm and the lower bridge arm of the second phase bridge arm respectively comprise power electronic devices Q3 and Q4, the upper bridge arm and the lower bridge arm of the third phase bridge arm respectively comprise power electronic devices Q5 and Q6, the three phase bridge arms are respectively connected with a three-phase stator winding L, and the three-phase stator winding L is connected in a Y-shaped connection mode to form a center tap. The voltage conversion device 2 has a first positive terminal 21 connected to a positive electrode on the dc side of the inverter, a second positive terminal 22 connected to a center tap of the three-phase stator winding L, and a negative terminal 23 connected to a negative electrode on the dc side of the inverter.

With continued reference to fig. 2, in the present embodiment, the first positive terminal 21, the second positive terminal 22, and the negative terminal 23 constitute an external power supply input side of the voltage conversion device 2, and the direct current side in the inverter constitutes an external power supply output side of the voltage conversion device 2. When the output voltage level of the external power supply connected to the input side of the external power supply matches, if equal to, the supply voltage level of the load connected to the output side of the external power supply, the first positive terminal 21 and the negative terminal 23 may be controlled to be connected to the external power supply, so that the direct current output from the external power supply may be directly input to the load for supplying power via the first positive terminal 21 and the negative terminal 23, and the positive electrode and the negative electrode on the direct current side in the inverter. When the output voltage level of the external power supply does not match the supply voltage level of the load, the second positive terminal 22 and the negative terminal 23 can be controlled to be connected with the external power supply, the inverter is controlled to perform voltage conversion on the direct current input from the second positive terminal 22 and the negative terminal 23, and the direct current after the voltage conversion is input to the load through the positive electrode and the negative electrode on the direct current side in the inverter to perform power supply. For example: if the output voltage level of the external power supply is less than the supply voltage level of the load, the inverter can be controlled to perform boost conversion on the direct current.

Referring again to fig. 1, in the embodiment of the present invention, the load connected to the output side of the external power supply may be a power battery of the vehicle, and the external power supply connected to the input side of the external power supply may be an external charging facility capable of charging the power battery. The first positive terminal 21 and the negative terminal 23 are controlled to be connected to the external charging facility when the output voltage level of the external charging facility matches the charging voltage level of the power battery, and the second positive terminal 22 and the negative terminal 23 are controlled to be connected to the external charging facility when the output voltage level of the external charging facility does not match the charging voltage level of the power battery. Further, in the present embodiment, a voltage conversion device disclosed in patent application with publication number CN112600411A may be adopted, and detailed description of the specific structure and operation principle of the voltage conversion device is omitted here.

Second, the power distribution equipment 3

The power distribution device 3 may be connected to the voltage conversion device 2 and the charging port capacitor (not shown in fig. 1), respectively, in the embodiment of the present invention. The power distribution apparatus 3 may be configured to switch the connection between the voltage conversion apparatus 2 and the charging port capacitance in response to an instruction sent by the charging control apparatus to form a conductive loop with the power battery 1, the voltage conversion apparatus 2, the power distribution apparatus 3, and the charging port capacitance when the charging port capacitance needs to be precharged or discharged, and thus the charging port capacitance may be precharged or discharged through this conductive loop. Meanwhile, the power distribution device 3 may be configured to switch the connection manner between the voltage conversion device 2 and the charging port capacitance in response to an instruction transmitted by the charging control device to control the power battery 1, the voltage conversion device 2, the power distribution device 3, the charging port 4 and the external charging facility to form a charging loop, and thus the power battery 1 may be charged through this charging loop.

Referring to fig. 2, in one embodiment, the power distribution apparatus 3 may include a first switch K1, a second switch K2, and a third switch K3, the first switch K1 being a single pole double throw switch. A first stationary contact a and a second stationary contact B of the first switch K1 are connected to a first positive terminal 21 and a second terminal of the second switch K2, respectively, a first terminal of the second switch K2 is connected to a second positive terminal 22, a first terminal C of a movable contact of the first switch K1 is connected to a positive input terminal 41 of the charging port 4, and a first terminal and a second terminal of the third switch K3 are connected to a negative terminal 23 and a negative input terminal 42 of the charging port 4, respectively. The first terminal and the second terminal of the charging port capacitor Cport are connected to the second terminal of the second switch K2 and the first terminal of the third switch K3, respectively.

According to the embodiment of the voltage conversion device 2, when the output voltage level of the external charging facility matches the charging voltage level of the power battery 1, the first positive terminal 21 and the negative terminal 23 can be controlled to be connected to the external charging facility, so that the direct current output by the external charging facility can be directly input to the power battery 1 for charging through the first positive terminal 21 and the negative terminal 23 and the positive electrode and the negative electrode on the direct current side in the inverter. Referring to fig. 3, when the output voltage level of the external charging facility matches the charging voltage level of the power battery 1, the first end C of the movable contact in the first switch K1 may be connected to the first stationary contact a so that the first positive terminal 21 is connected to the positive input terminal 41 of the charging port 4, while the third switch K3 is closed so that the negative terminal 23 is connected to the negative input terminal 42 of the charging port 4, so that the power battery 1, the voltage conversion device 2, the power distribution device 3, and the external charging facility may form a charging loop through which the external charging facility may charge the power battery by the above-described switch control. Since the charging port capacitor Cport is not connected to the charging loop, the charging port capacitor Cport does not need to be pre-charged before the power battery is charged, and the external charging facility can be directly controlled to charge the power battery after the first switch K1 and the third switch K3 are controlled. Further, when the charging is finished, since the charging port capacitor Cport does not store electric energy, there is no safety risk, and therefore, it is not necessary to discharge the charging port capacitor Cport, and the movable contact of the first switch K1 can be directly controlled to suspend and open the third switch (the switch states of the first switch K1 and the third switch K3 shown in fig. 2), so as to finish the charging.

According to the embodiment of the voltage conversion device 2, when the output voltage level of the external charging facility does not match the charging voltage level of the power battery 1, the second positive terminal 22 and the negative terminal 23 can be controlled to be connected to the external charging facility, so that the direct current output by the external charging facility can be directly input to the power battery 1 for charging through the second positive terminal 22 and the negative terminal 23 and the positive electrode and the negative electrode on the direct current side in the inverter. Referring to fig. 4, the first end C of the movable contact of the first switch K1 may be connected to the second stationary contact B so that the second positive terminal 22 is connected to the positive input terminal 41 of the charging port 4, and the second switch K2 and the third switch K3 may be closed, whereby the power battery 1, the voltage conversion device 2, the power distribution device 3, and the external charging facility may form a charging loop through which the power battery may be charged by the external charging facility. Since the charging port capacitor Cport is connected to this charging circuit, the charging port capacitor Cport needs to be precharged before the power battery is charged, and also needs to be discharged when the charging is finished.

Third, charging control equipment

In the embodiment of the present invention, the charge control device may be configured to perform the following operations:

when the output voltage level of the external charging facility connected to the charging port 4 of the vehicle charging system does not match the charging voltage level of the power battery 1, the voltage conversion device 2, the power distribution device 3, and the charging port capacitor may be controlled to form a conduction loop in response to a received charging start instruction or charging stop instruction, and the power battery may be controlled to pre-charge the charging port capacitor through the conduction loop or the charging port capacitor may be controlled to discharge through the conduction loop. The charge start command is a command for starting charging of the power battery by the vehicle using the charging facility, and the charge stop command is a command for stopping charging of the power battery by the vehicle using the charging facility.

Specifically, the charge control apparatus may be configured to pre-charge or discharge the charging port capacitance by performing the following operations when the output voltage level of the external charging facility to which the charging port 4 of the vehicle charging system is connected does not match the charging voltage level of the power battery 1:

in response to the received charging start instruction, controlling the power battery 1, the voltage conversion device 2, the power distribution device 3 and the charging port capacitor to form a conducting loop, and controlling the power battery 1 to pre-charge the charging port capacitor through the conducting loop; and controlling the voltage conversion device 2, the power distribution device 3, and the charging port capacitor to form a conductive loop in response to the received charging stop instruction, and controlling the charging port capacitor to discharge through this conductive loop.

In one implementation of the embodiment of the present invention, the charging control device may include a charging start control module, and the charging start control module may include a capacitor pre-charging sub-module. In the present embodiment, the capacitance pre-charging sub-module may be configured to pre-charge the charging port capacitance Cport by performing the following operations when the power distribution apparatus 3 shown in fig. 2 is employed:

step 11: in response to the received charging start command, the second switch K2 and the third switch K3 are closed, and the second end of the movable contact in the first switch K1 is controlled to be connected with the second fixed contact B, so that the power battery 1, the voltage conversion device 2, the second switch K2 and the charging port capacitor Cport form a conducting loop.

Step 12: and controlling the voltage conversion equipment 2 to reduce the voltage of the electric energy output by the power battery 1, transmitting the reduced voltage electric energy to the charging port capacitor Cport for pre-charging through the conducting loop formed in the step 11, and stopping pre-charging when the voltage of the charging port capacitor Cport reaches a set value. That is, the charging port capacitor Cport is precharged with the electric energy stored in the power battery 1, and before the precharging, the electric energy output from the power battery 1 is stepped down so that the voltage level of the electric energy output from the power battery 1 matches the charging voltage level of the charging port capacitor Cport, and then the charging port capacitor Cport is precharged with the power battery 1.

In the present embodiment, the on/off control of the arms of the inverter in the voltage conversion device 2 may be performed so that the voltage conversion device 2 can step down the electric energy output from the power battery 1. For example, all upper arms in the inverter may be controlled to remain in an on state (i.e., power electronics Q1, Q3, and Q5 are controlled to remain in an on state), and all lower arms may be controlled to remain in an off state (i.e., power electronics Q2, Q4, and Q6 are controlled to remain in an off state). In addition, all upper bridge arms in the inverter can be controlled to be connected for a period of time, and then all the upper bridge arms are controlled to be disconnected. And controlling all the lower bridge arms to be switched off during the switching-on period of the upper bridge arm, controlling all the lower bridge arms to be switched on during the switching-off period of the upper bridge arm, and enabling the switching-on time of the upper bridge arm to be longer than that of the lower bridge arm.

Further, in the embodiment of the present invention, the charging start control module may further include a first power battery charging submodule and a second power battery charging submodule, the first power battery charging submodule may be used to charge the power battery 1 when the output voltage level of the external charging facility connected to the charging port 4 matches the charging voltage level of the power battery 1, and the second power battery charging submodule may be used to charge the power battery 1 when the output voltage level of the external charging facility connected to the charging port 4 does not match the charging voltage level of the power battery 1. The first power battery charging submodule and the second power battery charging submodule are specifically explained below.

1. First power battery charging submodule

In an embodiment of the present invention, the first power battery charging submodule may be configured to charge the power battery 1 by performing the following operations when the output voltage level of the external charging facility to which the charging port 4 is connected matches the charging voltage level of the power battery 1 using the power distribution apparatus 3 shown in fig. 2:

in response to the received charging start instruction, the third switch K3 is closed and the second end of the movable contact in the first switch K1 is controlled to be connected with the first stationary contact a, so that the power battery 1, the voltage conversion device 2, the power distribution device 3, the charging port 4 and the external charging facility form a charging loop, and the external charging facility is controlled to charge the power battery 1 through this charging loop.

2. Charging submodule of second power battery

In an embodiment of the present invention, the second power battery charging submodule may be configured to charge the power battery by performing the following operations when the output voltage level of the external charging facility to which the charging port 4 is connected and the charging voltage level of the power battery 1 are not matched using the power distribution apparatus 3 shown in fig. 2:

after the capacitor pre-charging submodule stops pre-charging, the connection switches (switches K4 and K5 shown in fig. 2) of the charging port 4 and the external charging facility are closed, so that the power battery 1, the voltage conversion device 2, the power distribution device 3, the charging port 4 and the external charging facility form a charging loop, and the external charging facility is controlled to charge the power battery 1 through the charging loop. Referring to the foregoing embodiment of the voltage conversion device 2, in the charging stage of the power battery, when the output voltage level of the external charging facility does not match the charging voltage level of the power battery 1, the voltage conversion device 2 needs to be controlled to perform electric energy conversion, such as boosting, on the dc power output by the external charging facility, so that the dc power after electric energy conversion matches the charging voltage level of the power battery 1.

The method for controlling the pre-charging of the charging port capacitor of the vehicle charging system shown in fig. 2 is further described with reference to fig. 6 by taking an external charging facility as an example of the charging pile. The charging voltage level of the power battery 1 in the vehicle is 800V in the present embodiment. Referring to fig. 6, the method for controlling the charging port capacitor precharge may include the following steps S101 to S105:

step S101: and (3) entering a handshake stage after the gun insertion is detected, and controlling the charging port 4 to be opened after connection switches K4 and K5 of the external charging facility are closed. That is, the control mode of connecting the switches K4 and K5 in the handshake phase is first closed and then opened after detecting that the charging gun of the charging post is inserted into the charging port (gun insertion) of the vehicle.

Step S102: it is detected whether the output voltage level of the external charging facility is 800V or 400V. If it is detected that the output voltage level is 800V, indicating that the output voltage level of the external charging facility matches the charging voltage level of the power battery 1, step S1031 is executed, and after the execution is completed, the process goes to step S105. If the output voltage level is detected to be 400V, which indicates that the output voltage level of the external charging facility does not match the charging voltage level of the power battery 1, the steps S1041 to S1043 are executed, and the process goes to the step S105 after the execution is completed.

Step S1031: closing the AC contact of the first switch K1 (connecting the movable contact of the first switch K1 with the first stationary contact a) and closing the third switch K3.

Step S1041: closing the BC contact of the first switch K1 (connecting the moving contact of the first switch K1 with the second stationary contact B)

Step S1042: the voltage conversion device 2 is controlled to step down the electric energy output by the power battery 1 and pre-charge the charging port capacitor.

Step S1043: the voltage conversion device 2 is controlled to stop operating after the completion of the precharge.

Step S105: the connection switches K4 and K5 of the charging port 4 and the external charging facility are closed. After the connection switches K4 and K5 are closed, the external charging facility can be controlled to charge the power battery 1. In the charging phase of the power battery, the control manner of the voltage conversion device 2 may refer to the foregoing method embodiment, and will not be described herein again.

In one implementation of the embodiment of the present invention, the charging control device may include a charging stop control module, and the charging stop control module may be configured to form a conducting loop for discharging the charging port capacitor by controlling the voltage conversion device 2 and the power distribution device 3 after stopping charging the power battery, and control the charging port capacitor to discharge through the conducting loop, so as to discharge the electric energy stored in the charging port capacitor in time after stopping charging the power battery, and avoid a safety accident such as an electric shock due to the electric energy stored in the charging port capacitor when a user disconnects an external charging facility from the vehicle charging system.

In the embodiment of the present invention, the charge stop instruction may include an instruction to stop charging the power battery and to control the power battery to continue to supply power to the high-voltage system in the vehicle after the charge stop (hereinafter, referred to as a first charge stop instruction), or may include an instruction to stop charging the power battery and to control the power battery to stop supplying power to the high-voltage system in the vehicle after the charge stop (hereinafter, referred to as a second charge stop instruction). Wherein, after stopping charging, controlling the power battery to continue to supply power to the high-voltage system in the vehicle means that: after the power battery is stopped to be charged, the power battery is still needed to be used for supplying power to a high-voltage system in the vehicle, and high-voltage accessories such as an air conditioner, an On Board Charger (OBC) (on charger) and a DC/DC converter in the high-voltage system are continuously supplied with power.

The following specifically describes the two types of charge stop commands.

(1) A first charging stop instruction

In the present embodiment, the second charge stop control submodule may be configured to discharge the charging port capacitance by performing the following operations when the power distribution apparatus 3 shown in fig. 2 is employed and the output voltage level does not match the charging voltage level:

in response to the received first charging stop instruction, the connection switches (switches K4 and K5 shown in fig. 2) of the charging port 4 and the external charging facility are opened, then the third switch K3 is opened and the movable contact in the first switch K1 is controlled to be suspended, so that the voltage conversion device 2, the power distribution device 3 and the charging port capacitance Cport form a conductive loop, and the charging port capacitance Cport is controlled to be discharged through this conductive loop.

In the present embodiment, the arms of the inverter in the voltage conversion device 2 may be on/off controlled so that the charging port capacitances Cport and the lower arms of the inverter form a plurality of short-time on-circuits, respectively. After each formation of a conductive loop, the charging port capacitor Cport may be discharged through the conductive loop.

Referring to fig. 2, the power electronic device Q2 may be first controlled to be turned on (all other power electronic devices are turned off), so that the charging port capacitor Cport, the stator winding L, and the power electronic device Q2 form a conducting loop, and the discharge current flows from the positive electrode of the charging port capacitor Cport (the end connected to the second switch K2) to the negative electrode of the charging port capacitor Cport (the end connected to the third switch K3) after sequentially flowing through the second positive electrode terminal 22, the stator winding L, the power electronic device Q2, and the negative electrode terminal 23. Then, the power electronic device Q4 is controlled to be turned on (other power electronic devices are all turned off), so that the charging port capacitor Cport, the stator winding L and the power electronic device Q2 form a conducting loop, and the discharge current flows from the positive electrode of the charging port capacitor Cport (the end connected to the second switch K2) to the negative electrode of the charging port capacitor Cport (the end connected to the third switch K3) after sequentially flowing through the second positive electrode terminal 22, the stator winding L, the power electronic device Q2 and the negative electrode terminal 23. Further, the power electronic device Q6 is controlled to be turned on (all other power electronic devices are turned off), so that the charging port capacitor Cport, the stator winding L, and the power electronic device Q2 form a conductive loop, and the discharge current flows from the positive electrode of the charging port capacitor Cport (the end connected to the second switch K2) to the second positive electrode terminal 22, the stator winding L, the power electronic device Q2, and the negative electrode terminal 23 in this order, and then flows to the negative electrode of the charging port capacitor Cport (the end connected to the third switch K3). And finally, continuously repeating the process until the voltage of the charging port capacitor Cport is reduced to a preset value, such as 60V, and stopping the discharge control.

(2) Second charge stop instruction

In the present embodiment, the charge stop control sub-module may be configured to directly discharge the charging port capacitance by performing the following operations when the power distribution apparatus 3 shown in fig. 2 is employed and the output voltage level does not match the charging voltage level:

in response to the received second charge stop instruction, the connection switches (switches K4 and K5 shown in fig. 2) of the charging port 4 and the external charging facility are opened, then the third switch K3 is opened and the movable contact in the first switch K1 is controlled to be suspended, so that the voltage conversion device 2, the power distribution device 3 and the charging port capacitance Cport form a conductive loop, and the charging port capacitance Cport is controlled to be discharged through this conductive loop.

In the present embodiment, the on/off control may be performed on the arms of the inverter in the voltage conversion device 2 so that the charging port capacitances Cport and the lower arms of the inverter form a plurality of short-time on-circuits. After each formation of a conductive loop, the charging port capacitor Cport may be discharged through the conductive loop.

It should be noted that, in the present embodiment, the control manner of the voltage conversion device 2 is the same as the control manner of the voltage conversion device 2 adopted by the charging stop control submodule according to the first charging stop instruction, and for brevity of description, no further description is given here.

Further, in an embodiment, referring to fig. 2, the voltage converting device 2 may further include a discharge circuit connected in parallel to the dc side of the inverter, and the discharge circuit may include a power electronic device Qdischarge and a resistor Rdischarge, a first main electrode of the power electronic device Qdischarge is connected to the positive electrode of the dc side, a second main electrode of the power electronic device Qdischarge is connected to a first end of the resistor Rdischarge, and a second end of the resistor Rdischarge is connected to the negative electrode of the dc side. That is, power electronics Qdischarge and resistor Rdischarge are connected in series and then connected in parallel to the dc side of the inverter.

In the present embodiment, the charge stop control submodule may be configured to discharge the charging port capacitance using the above-described discharge circuit and by performing the following operations when the power distribution apparatus 3 shown in fig. 2 is employed and the output voltage level does not match the charging voltage level:

in response to the received charge stop instruction, the connection switches (switches K4 and K5 shown in fig. 2) of the charging port 4 and the external charging facility are opened, then the third switch K3 is opened and the movable contact in the first switch K1 is controlled to be suspended, the connection switches (switches Kpos + and Kneg-shown in fig. 2) between the power battery 1 and the inverter are opened, and finally the power electronics Qdischarge is controlled to be turned on, so that the voltage conversion device 2, the power distribution device 3 and the charging port capacitance Cport form a conductive loop, and the charging port capacitance Cport is controlled to be discharged through the conductive loop.

In the present embodiment, one diode is provided in reverse parallel with each power electronic device in the voltage conversion device 2, and as shown in fig. 2, the power electronic devices Q1 to Q6 and the power electronic device Qdischarge are each in reverse parallel with one diode. After the power electronic device Qdischarge is controlled to be turned on, the charging port capacitor Cport may be connected in parallel (parallel branch) with the discharge circuit, or may be connected in parallel (series-parallel branch) with the dc bus capacitor Cbus of the inverter by forming a series branch through a diode in each upper bridge arm of the inverter in the voltage converting device 2. That is to say, the on circuit formed after controlling the power electronic device Qdischarge to be on includes the parallel branch and the series-parallel branch, and the charging port capacitor Cport can be discharged not only through the parallel branch but also through the series-parallel branch, so that the discharging speed of the charging port capacitor Cport is significantly increased.

The following will further describe the discharge control method of the charging port capacitor of the vehicle charging system shown in fig. 2 by taking an external charging facility as an example of the charging pile and referring to fig. 7. The charging voltage level of the power battery 1 in the vehicle is 800V in the present embodiment, and the output voltage level of the external charging facility is also 400V. Referring to fig. 7, the method for controlling the discharge of the charging port capacitor may include the following steps S201 to S205:

step S201: detecting whether the power battery 1 continues to supply power to the high-voltage system after the 400V charging is finished; if the power supply is continued, go to step S204 after step S2021-step S2023 are executed; if no power is supplied, step S2031 to step S2034 are executed, and the process proceeds to step S204.

Step S2021: the connection switches K4 and K5 of the charging port 4 and the external charging facility are disconnected.

Step S2022: open K1 (moving contact flying) and open K3.

Step S2023: the voltage conversion device 2 is controlled to discharge the charging port capacitance.

Step S2031: the connection switches K4 and K5 of the charging port 4 and the external charging facility are disconnected.

Step S2032: open K1 (moving contact flying) and open K3.

Step S2033: the connection switches Kpos + and Kneg-between the power battery 1 and the inverter are disconnected.

Step S2034: the voltage conversion device 2 is controlled to discharge the charging port capacitance.

Step S204: and detecting whether the voltage of the capacitor at the charging port reaches a set value. If not, go to step S2023 or step S2034. If so, go to step S205.

After the process goes to step S204 after step S2021-step S2023 are executed, the process goes to step S2023 if the voltage of the charging port capacitor does not reach the set value. After proceeding to step S204 after executing step S2031 to step S2034, the process proceeds to step S2034 if the voltage of the charging port capacitance does not reach the set value.

Step S205: the second switch K2 is opened. After the K2 is turned off, the charging gun can be pulled out of the vehicle (gun pulling), and the charging is finished.

So far, the technical solution of the vehicle charging system of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. The vehicle charging system can not only utilize the voltage conversion equipment to consider charging facilities with different voltage grades on the market, but also pre-charge and discharge the charging port capacitor through a conducting loop formed by the charging control equipment, the power distribution equipment and the like, so that the charging facilities can be safely and effectively used for charging the vehicle under the condition that the voltage grades of the vehicle and the charging facilities are not matched. Meanwhile, when the output voltage level is matched with the charging voltage level, the capacitor of the charging port is not required to be pre-charged, the power battery, the voltage conversion equipment, the power distribution equipment, the charging port and an external charging facility can be directly controlled to form a charging loop of the power battery, the power battery is charged, the capacitor of the charging port is not required to be discharged when the charging is finished, the charging process of the power battery is simplified, and the operation convenience of charging the power battery is improved.

Further, the present invention provides a vehicle, in an embodiment of the vehicle according to the present invention, the vehicle may include a power battery and an electric drive system, the electric drive system may include an inverter and an electric motor, a dc side of the inverter is connected to the power battery, an ac side of the inverter is connected to a stator winding of the electric motor, and the vehicle may further include the vehicle charging system described in the foregoing embodiment of the vehicle charging system. For convenience of explanation, only the parts related to the embodiments of the present invention are shown, and details of the specific technology are not disclosed.

It will be understood by those skilled in the art that all or part of the processes in the system implementing one embodiment of the present invention may also be implemented by instructing the relevant hardware through a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the above-described method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying said computer program code, media, usb disk, removable hard disk, magnetic diskette, optical disk, computer memory, read-only memory, random access memory, electrical carrier wave signals, telecommunication signals, software distribution media, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.

Further, it should be understood that, since the configuration of each module is only for explaining the functional units of the apparatus of the present invention, the corresponding physical devices of the modules may be the processor itself, or a part of software, a part of hardware, or a part of a combination of software and hardware in the processor. Thus, the number of individual modules in the figures is merely illustrative.

Those skilled in the art will appreciate that the various modules in the apparatus may be adaptively split or combined. Such splitting or combining of specific modules does not cause the technical solutions to deviate from the principle of the present invention, and therefore, the technical solutions after splitting or combining will fall within the protection scope of the present invention.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

Claims

1. A vehicle charging system, the vehicle including a power battery and an electric drive system, the electric drive system including an inverter and a motor, a direct current side of the inverter being connected with the power battery, an alternating current side of the inverter being connected with a stator winding of the motor, the vehicle charging system including a voltage conversion device, the voltage conversion device including the inverter, the stator winding, a first positive terminal, a second positive terminal and a negative terminal, the first positive terminal and the negative terminal being connected with a positive electrode and a negative electrode of the direct current side, respectively, the second positive terminal being connected with a center tap of the stator winding,

it is characterized in that the preparation method is characterized in that,

the vehicle charging system further comprises a charging port, a charging port capacitor, power distribution equipment and charging control equipment, wherein the power distribution equipment is respectively connected with the voltage conversion equipment and the charging port capacitor;

the charge control device is configured to:

2. The vehicle charging system of claim 1, wherein the charging port includes a positive input terminal and a negative input terminal;

3. The vehicle charging system of claim 2, wherein the charge control device comprises a charge initiation control module comprising a capacitor pre-charge sub-module;

4. The vehicle charging system of claim 3, wherein the charge initiation control module further comprises a first power battery charging sub-module;

5. The vehicle charging system of claim 3, wherein the charge initiation control module further comprises a second power battery charging submodule;

6. The vehicle charging system of claim 5, wherein the charging control device comprises a charging stop control module configured to discharge the charging port capacitance by performing the following operations:

7. The vehicle charging system according to claim 6, wherein the voltage conversion device further includes a discharge circuit connected in parallel to a direct current side in the inverter, the discharge circuit including a power electronic device and a resistor, a first main electrode of the power electronic device being connected to a positive electrode of the direct current side, a second main electrode of the power electronic device being connected to a first end of the resistor, and a second end of the resistor being connected to a negative electrode of the direct current side.

8. The vehicle charging system of claim 7, wherein when the charge stop command is a command to stop charging a power battery and to control the power battery to no longer power a high voltage system within the vehicle after stopping charging, the charge stop control submodule is further configured to discharge the charge port capacitance by performing the following operations:

9. A vehicle comprising a power battery and an electric drive system comprising an inverter and an electric motor, the dc side of the inverter being connected to the power battery and the ac side of the inverter being connected to the stator windings of the electric motor, characterized in that the vehicle further comprises a vehicle charging system as claimed in any one of claims 1 to 8.