Electric vehicle DC boost charging control system, control method and vehicle

Abstract

The present invention discloses a DC boost charging control system, a control method and a vehicle for electric vehicles, including a charging mode recognition module, a power battery control module, an electric system capacity estimation module, a charging port temperature acquisition module, a charging parameter configuration module, a DC charging pile control module, a relay control module, a whole vehicle charging condition judgment module, a DC charging state control module and an electric drive charging boost coordination module; the electric system capacity estimation module is connected to the charging mode recognition module; the charging parameter configuration module is respectively connected to the power battery control module, the electric system capacity estimation module and the charging port temperature acquisition module; the DC charging state control module is respectively connected to the charging parameter configuration module, the DC charging pile control module, the relay control module and the whole vehicle charging condition judgment module. The present invention can solve the problem that the charging process of a vehicle equipped with an energy conversion device is not fully matched with the DC charging pile, resulting in failure to charge.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current charging of electric vehicles, and in particular relates to a direct current boost charging control system, a control method and a vehicle for electric vehicles. Background Art

[0002] As people's demand for the driving range of new energy vehicles continues to increase, more and more vehicle manufacturers are developing high-voltage platform batteries to meet customers' demand for driving range. However, most DC charging piles on the market are limited by the charging output voltage and cannot support the charging of high-voltage platform batteries, which requires customers to find suitable DC charging piles, affecting customer experience.

[0003] In order to solve the above problems, energy conversion devices have emerged, such as an energy conversion device and a vehicle disclosed in patent document CN 210225008 U, which realizes charging in a wide voltage range by using an energy conversion device. However, the interactive judgment logic between the vehicle and the DC charging pile is complex, and the motor controller and the motor are used for boost charging throughout the whole process. If no further processing is done, it will not only lead to low vehicle charging efficiency and affect the service life of the motor and electronic control, but also the charging process of the vehicle equipped with the energy conversion device will not fully match the DC charging pile, resulting in the phenomenon of being unable to charge. Secondly, the power modules of most DC charging piles are started in stages. If the current output is too large under constant voltage output, the DC charging pile output will be undervoltage, thereby terminating charging.

[0004] Therefore, it is necessary to develop a new electric vehicle DC boost charging control system, control method and vehicle. Summary of the invention

[0005] The object of the present invention is to provide an electric vehicle DC boost charging control system, a control method and a vehicle, which can solve the problem that the charging process of a vehicle equipped with an energy conversion device is not completely matched with a DC charging pile, resulting in failure to charge.

[0006] In the first aspect, the present invention provides an electric vehicle DC boost charging control system, comprising a charging mode recognition module, a power battery control module, an electric system capacity estimation module, a charging port temperature acquisition module, a charging parameter configuration module, a DC charging pile control module, a relay control module, a vehicle charging condition judgment module, a DC charging state control module, an electric drive charging boost coordination module and an execution electronic control;

[0007] The charging mode identification module is used to determine whether the current charging mode is a DC charging mode or an AC charging mode after the CC signal is connected;

[0008] The power battery control module is used to monitor and feedback the battery current, the highest cell voltage, the lowest cell voltage, the highest cell temperature, the lowest cell temperature, the average temperature and the battery heating demand, and calculate and feedback the current allowable charging capacity of the battery;

[0009] The electric system capacity estimation module is used to calculate and feed back the sum of the actual power consumption of the high-voltage load, and the electric system capacity estimation module is connected to the charging mode identification module;

[0010] The charging port temperature collection module is used to collect the temperature of the charging plug socket;

[0011] The charging parameter configuration module is used to calculate the required voltage and current during external charging according to the power supply system, temperature limit coefficient and battery demand. The charging parameter configuration module is respectively connected to the power battery control module, the power system capacity estimation module and the charging port temperature acquisition module;

[0012] The DC charging pile control module is used to collect the working voltage and current range of the DC charging pile;

[0013] The relay control module is used to control the closing and opening of each relay in the charging circuit;

[0014] The vehicle charging condition judgment module is used to judge the conditions for allowing or prohibiting charging of the vehicle, and to feed back the judgment result;

[0015] The DC charging state control module parses the signals and instructions fed back by the charging mode identification module, the power battery control module, the electric system capacity estimation module, the charging port temperature acquisition module, the charging parameter configuration module, the DC charging pile control module, the relay control module, and the whole vehicle charging condition judgment module into the corresponding electric drive charging transformer mode request and sends it to the electric drive charging boost coordination module, and is also responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the highest output voltage of the DC charging pile received is less than or equal to the preset value, the control system enters the boost charging process; if the highest output voltage of the DC charging pile received is greater than the preset value, the control system enters the DC charging process, and the DC charging state control module is respectively connected to the charging parameter configuration module, the DC charging pile control module, the relay control module, and the whole vehicle charging condition judgment module;

[0016] The electric drive charging boost coordination module enters a corresponding mode according to the electric drive charging voltage transformation mode request sent by the DC charging state control module and controls the execution electronic control to perform corresponding actions. The electric drive charging boost coordination module is respectively connected to the DC charging state control module and the execution electronic control.

[0017] In a second aspect, a DC boost charging control method for an electric vehicle described in the present invention establishes a connection between the vehicle end and the DC charging pile; wherein the vehicle end includes a power battery, a main positive relay, a pre-charging relay, a pre-charging resistor, a charging positive relay, an energy conversion device, a charging port capacitor, a boost charging relay and a DC charging relay, the positive end of the power battery is respectively connected to the energy conversion device and one end of the charging positive relay via the main positive relay, the other end of the charging positive relay is respectively connected to the energy conversion device and one end of the boost charging relay via the charging port capacitor, the other end of the boost charging relay is connected to the negative end of the power battery via the DC charging relay, the pre-charging relay and the pre-charging resistor are connected in series and then connected in parallel with the main positive relay; the vehicle end is also integrated with the electric vehicle DC boost charging control system as described in the present invention, and its control method includes:

[0018] The charging mode identification module determines whether the current charging mode is a DC charging mode or an AC charging mode according to the CC signal access;

[0019] The power battery control module monitors and feeds back the battery current, maximum cell voltage, minimum cell voltage, maximum cell temperature, minimum cell temperature, average temperature and battery heating requirements, and calculates and feeds back the current allowable charging capacity of the battery;

[0020] The electrical system capacity estimation module calculates and feeds back the sum of the actual power consumption of the high voltage load;

[0021] The charging port temperature collection module collects the temperature of the charging plug socket;

[0022] The charging parameter configuration module calculates the required voltage and current for external charging according to the power supply system, temperature limit coefficient and battery requirements;

[0023] The DC charging pile control module collects the operating voltage and current range of the DC charging pile;

[0024] The vehicle charging condition judgment module judges the conditions for allowing or prohibiting charging of the vehicle, and feeds back the judgment result;

[0025] The DC charging state control module parses the signals and instructions fed back by the charging mode identification module, the power battery control module, the electric system capacity estimation module, the charging port temperature acquisition module, the charging parameter configuration module, the DC charging pile control module, the relay control module, and the vehicle charging condition judgment module into corresponding electric drive charging transformer mode requests and sends them to the electric drive charging boost coordination module. At the same time, it is responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the maximum output voltage of the DC charging pile is less than or equal to the preset value, the control system enters the boost charging process; if the maximum output voltage of the DC charging pile is greater than the preset value, the control system enters the DC charging process;

[0026] The electric drive charging boost coordination module enters the corresponding mode according to the electric drive charging voltage transformation mode request sent by the DC charging state control module and controls the execution electronic control 11 to perform corresponding actions.

[0027] Optionally, the boost charging process is specifically as follows:

[0028] Step 301: configure charging parameters;

[0029] Step S302: After confirming that the parameter configuration is complete, the DC charging state control module requests the energy conversion device to enter the boost mode, and the electric drive charging boost coordination module responds to the instruction;

[0030] Step S303: The DC charging state control module determines whether the maximum output voltage of the DC charging pile is less than or equal to a preset value; if not, proceed to step S304; if so, proceed to step S305 and step S306;

[0031] Step S304: Jump to the DC charging process;

[0032] Step S305: Send the required voltage U1 and the required current I1 to the DC charging pile, and proceed to step S307;

[0033] Step S306: Send the required voltage U to the energy conversion device req , the required current is I req ;

[0034] Step S307: The DC charging state control module determines the output current of the DC charging pile. If the DC charging pile has output current, the process proceeds to step S308, otherwise, the process returns to step S305;

[0035] Step S308: the required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1;

[0036] Step S309: The DC charging state control module determines whether the required voltage sent to the DC charging pile rises to U2. If so, it proceeds to step S310, otherwise it returns to step S308;

[0037] Step S310: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is to slowly increase the current from I1 to I2 at a preset rate;

[0038] Step S311: The system enters a normal boost charging state.

[0039] Optionally, the DC charging process is specifically as follows:

[0040] Step S401: configure charging parameters;

[0041] Step S402: After confirming that the parameter configuration is complete, the DC charging state control module requests the energy conversion device to enter the boost mode, and the electric drive charging boost coordination module responds to the instruction;

[0042] Step S403: The DC charging state control module determines whether the maximum output voltage of the DC charging pile is greater than a preset value. If the maximum output voltage of the DC charging pile is greater than 500V, the process proceeds to step S405 and step S406; otherwise, the process proceeds to step S404;

[0043] Step S404: Jump to the boost charging process;

[0044] Step S405: Sending the required voltage U1 and the required current I1 to the DC charging pile, and proceeding to step S407;

[0045] Step S406: Send the required voltage U to the energy conversion device req , the required current is I req , and proceed to step S415;

[0046] Step S407: The DC charging state control module determines whether the DC charging pile outputs current. If the DC charging pile outputs current, the process proceeds to step S408; otherwise, the process returns to step S405.

[0047] Step S408: The required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1;

[0048] Step S409: The DC charging state control module determines whether the required voltage rises to U2, if so, proceeds to step S410, otherwise returns to step S408;

[0049] Step S410: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is I3;

[0050] Step S411: The DC charging state control module determines the output current of the DC charging pile. If the output current of the DC charging pile drops to I3, the process proceeds to step S412, otherwise, the process returns to step S410;

[0051] Step S412: closing the DC charging relay and disconnecting the boost charging relay;

[0052] Step S413: Sending a required voltage U to the DC charging pile req , the demand current is I2;

[0053] Step S414: the system enters a normal DC charging state;

[0054] Step S415: The DC charging state control module determines the state of the boost charging relay. If the boost charging relay is disconnected, proceed to step S416, otherwise, return to step S406;

[0055] Step S416: turning off the output of the energy conversion device;

[0056] Step S417: Control the energy conversion device to enter the no-request mode.

[0057] Optionally, the charging parameter configuration process includes:

[0058] Step S201: The DC charging pile control module inputs the DC charging pile insulation detection completion status;

[0059] Step S202: After the insulation test is completed, the vehicle sends the current battery voltage U1 to the DC charging pile;

[0060] Step S203: The DC charging state control module determines whether the maximum output capacity of the DC charging pile is received. If so, it proceeds to step S204; if not, it returns to step S202;

[0061] Step S204: Control the boost charging relay to close and complete the high voltage power-on operation;

[0062] Step S205: The DC charging state control module requests the energy conversion device to enter the step-down mode and requests to step down the voltage to U1, and the electric drive charging boost coordination module responds to the instruction and performs the step-down operation;

[0063] Step S206: The DC charging state control module determines whether the voltage reduction is completed. If it is completed, it goes to step S207, otherwise it returns to step S205;

[0064] Step S207: Inform the DC charging pile that the vehicle is ready.

[0065] Optionally, the value of U1 is the smaller value of the minimum total discharge voltage of the battery minus the first offset and the maximum output voltage of the DC charging pile; the value of I1 is the smaller value of the allowable charging current of the battery and the safe charging current; wherein, subtracting the first offset from the minimum total discharge voltage of the battery can ensure that the output voltage of the DC charging pile is lower than the battery voltage, so that the energy conversion device can be used for boost charging; taking the smaller value of the maximum output voltage of the DC charging pile can ensure that the battery voltage is within the range allowed by the DC charging pile each time, and prevent the DC charging pile from reporting a charging parameter mismatch fault. Taking the smaller value of the allowable charging current of the battery and the safe charging current can ensure that when the DC charging pile quickly adjusts the output voltage, the voltage will not be unstable due to excessive current, and the safe current can be calibrated.

[0066] Optionally, the value of U2 is the smaller value of the current total voltage of the battery minus the second offset and the maximum output voltage of the DC charging pile; the value of I2 is the allowable charging current of the battery.

[0067] Optionally, the U req The value of is the total battery voltage plus the third offset;

[0068] I req The value of Among them, BCL is the code specified by the national standard, which refers to the charging demand sent by the battery to the DC charging pile.

[0069] Optionally, the value of I3 is the minimum output current of the DC charging pile.

[0070] In a third aspect, a vehicle described in the present invention adopts the electric vehicle DC boost charging control system described in the present invention.

[0071] The present invention has the following advantages: the present invention solves the problem that the charging process of a vehicle equipped with an energy conversion device is not fully matched with a DC charging pile, resulting in the inability to charge, greatly reduces the problem of long-term use of boost charging affecting the charging efficiency and the service life of the motor and electronic control, and at the same time solves the problem of undervoltage caused by slow output power adjustment of some DC charging piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a structural diagram of the electric vehicle DC boost charging control system in this embodiment;

[0073] Figure 2 Schematic diagram of the DC boost charging structure in this embodiment;

[0074] Figure 3 is a flow chart of the DC boost charging parameter configuration stage in this embodiment;

[0075] Figure 4 is a flow chart of the charging phase using a boost charging circuit in this embodiment;

[0076] Figure 5 FIG. 4 is a flow chart of the charging phase using a DC charging circuit in this embodiment. DETAILED DESCRIPTION

[0077] The present invention will be described in detail below with reference to the accompanying drawings.

[0078] like Figure 1As shown, in this embodiment, a DC boost charging control system for an electric vehicle includes a charging mode recognition module 1, a power battery control module 2, an electric system capacity estimation module 3, a charging port temperature acquisition module 4, a charging parameter configuration module 5, a DC charging pile control module 6, a relay control module 7, a vehicle charging condition judgment module 8, a DC charging state control module 9, an electric drive charging boost coordination module 10 and an execution electronic control 11; wherein:

[0079] The charging mode identification module 1 is used to determine whether the current charging mode is a DC charging mode or an AC charging mode after the CC signal is connected;

[0080] The power battery control module 2 is used to monitor and feedback the battery current, the highest cell voltage, the lowest cell voltage, the highest cell temperature, the lowest cell temperature, the average temperature and the battery heating demand, and calculate and feedback the current allowable charging capacity of the battery;

[0081] The electric system capacity estimation module 3 is used to calculate and feed back the sum of the actual power consumption of high-voltage loads (including DCDC, DCAC, drive motor and other high-voltage loads), and the electric system capacity estimation module 3 is connected to the charging mode identification module 1;

[0082] The charging port temperature collection module 4 is used to collect the temperature of the charging plug socket;

[0083] The charging parameter configuration module 5 is used to calculate the required voltage and required current during external charging according to the power supply system, temperature limit coefficient and battery demand. The charging parameter configuration module 5 is respectively connected to the power battery control module 2, the power system capacity estimation module 3 and the charging port temperature acquisition module 4;

[0084] The DC charging pile control module 6 is used to collect the working voltage and current range of the DC charging pile;

[0085] The relay control module 7 is used to control the closing and opening of each relay in the charging circuit;

[0086] The vehicle charging condition judgment module 8 is used to judge the conditions for allowing or prohibiting charging of the vehicle, and to feed back the judgment result;

[0087] The DC charging state control module 9 parses the signals and instructions fed back by the charging mode identification module 1, the power battery control module 2, the electric system capacity estimation module 3, the charging port temperature acquisition module 4, the charging parameter configuration module 5, the DC charging pile control module 6, the relay control module 7, and the vehicle charging condition judgment module 8 into corresponding electric drive charging transformer mode requests (no request, boost mode, buck mode) and sends them to the electric drive charging boost coordination module 10, and is also responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the highest output voltage of the DC charging pile is less than or equal to the preset value (500V), the control system enters the boost charging process (see attached Figure 4 ); If the maximum output voltage of the DC charging pile is greater than the preset value (500V), the control system enters the DC charging process (see Appendix Figure 5 ), the DC charging state control module 9 is respectively connected to the charging parameter configuration module 5, the DC charging pile control module 6, the relay control module 7, and the vehicle charging condition judgment module 8;

[0088] The electric drive charging boost coordination module 10 enters the corresponding mode according to the electric drive charging voltage transformation mode request (no request, boost mode, buck mode) sent by the DC charging state control module 9 and controls the execution electronic control 11 to perform corresponding actions. The electric drive charging boost coordination module 10 is respectively connected to the DC charging state control module 9 and the execution electronic control 11.

[0089] The execution electronic control 11 performs corresponding actions according to the control signal of the DC charging state control module 9 .

[0090] In this embodiment, a DC boost charging control method for an electric vehicle is provided, wherein a vehicle end is connected to a DC charging pile; wherein the vehicle end includes a power battery, a main positive relay, a pre-charging relay, a pre-charging resistor, a charging positive relay, an energy conversion device (composed of a high voltage part of a motor controller and a motor winding), a charging port capacitor, a boost charging relay and a DC charging relay, wherein the positive end of the power battery is respectively connected to the energy conversion device and one end of the charging positive relay via the main positive relay, the other end of the charging positive relay is respectively connected to the energy conversion device and one end of the boost charging relay via the charging port capacitor, the other end of the boost charging relay is connected to the negative end of the power battery via the DC charging relay, the pre-charging relay and the pre-charging resistor are connected in series and then connected in parallel with the main positive relay; the vehicle end is also integrated with a DC boost charging control system for an electric vehicle as described in the present invention, and the control method thereof includes:

[0091] The charging mode identification module 1 determines whether the current charging mode is a DC charging mode or an AC charging mode according to the CC signal access;

[0092] The power battery control module 2 monitors and feeds back the battery current, the highest cell voltage, the lowest cell voltage, the highest cell temperature, the lowest cell temperature, the average temperature and the battery heating requirement, and calculates and feeds back the current allowable charging capacity of the battery;

[0093] The electrical system capacity estimation module 3 calculates and feeds back the sum of the actual power consumption of the high voltage load;

[0094] The charging port temperature collection module 4 collects the temperature of the charging plug socket;

[0095] The charging parameter configuration module 5 calculates the required voltage and current during external charging according to the power supply system, temperature limit coefficient and battery requirements;

[0096] The DC charging pile control module 6 collects the operating voltage and current range of the DC charging pile;

[0097] The vehicle charging condition judgment module 8 judges the conditions for allowing or prohibiting charging of the vehicle, and feeds back the judgment result;

[0098] The DC charging state control module 9 parses the signals and instructions fed back by the charging mode identification module 1, the power battery control module 2, the electric system capacity estimation module 3, the charging port temperature acquisition module 4, the charging parameter configuration module 5, the DC charging pile control module 6, the relay control module 7, and the vehicle charging condition judgment module 8 into corresponding electric drive charging transformer mode requests and sends them to the electric drive charging boost coordination module 10. At the same time, it is responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the maximum output voltage of the DC charging pile received is less than or equal to the preset value, the control system enters the boost charging process; if the maximum output voltage of the DC charging pile received is greater than the preset value, the control system enters the DC charging process;

[0099] The electric drive charging boost coordination module 10 enters a corresponding mode according to the electric drive charging voltage transformation mode request sent by the DC charging state control module 9 and controls the execution electronic control 11 to perform corresponding actions.

[0100] In this embodiment, two charging circuits are provided. When the maximum output voltage of the DC charging pile does not meet the maximum voltage of the battery, the boost charging relay is closed to make the DC charging pile output to the energy conversion device (composed of a motor controller and a motor winding), and the energy conversion device provides energy to the battery system after completing the boost. When the maximum output voltage of the DC charging pile meets the maximum voltage of the battery, the DC charging relay is closed to directly connect the DC charging pile to the battery system, avoiding energy transmission through the energy conversion device, reducing the loss of the motor winding and IGBT, and improving the charging efficiency.

[0101] In this embodiment, when boost charging is proposed, the problem of DC charging pile output undervoltage caused by slow output power regulation of some DC charging piles is solved by adjusting the charging current rising rate, thereby improving the reliability and compatibility of boost charging.

[0102] In this embodiment, the interactive control process of electric vehicles being compatible with DC charging piles with different output voltage ranges is clarified, which solves the problem of being unable to charge due to the incomplete matching of the charging process of vehicles equipped with energy conversion devices with DC charging piles.

[0103] In this embodiment, after the handshake phase of the DC charging process is completed, the vehicle closes the boost charging relay and completes the high-voltage power-on. In the charging parameter message, the "current battery voltage of the vehicle power battery" is sent as U1. After receiving the output capacity of the DC charging pile, the energy conversion device is made to step down and output, and the capacitor voltage of the vehicle charging port is precharged to U1 for external voltage judgment of the DC charging pile. Since the national standard requires that the message interaction type between the vehicle and the DC charging pile is event-type, and stipulates that the DC charging pile will feedback the output capacity only after the vehicle sends its current voltage parameters, before receiving the output capacity of the DC charging pile, a battery voltage that meets the output voltage capacity of all specifications of the DC charging pile is first fed back, and the capacitor voltage of the vehicle charging port is precharged to the target value through the energy conversion device to ensure that the DC charging pile determines that the vehicle battery voltage meets the output capacity range, so that it can successfully enter the charging process.

[0104] In this embodiment, after completing the parameter configuration, the vehicle determines the charging demand and the charging circuit switching process according to the output capacity of the DC charging pile received previously.

[0105] like Figure 2 The figure shows a schematic diagram of the DC boost charging structure. After closing the main positive relay, the charging positive relay and the boost charging relay, the step-down capacitor is charged to the target voltage through the energy conversion device for detection by the DC charging pile. If boost charging is required after entering the charging process, the boost charging relay is kept closed. If DC charging is required, the DC charging relay is closed and the boost charging relay is disconnected.

[0106] In this embodiment, Figure 3 As shown, the process of the DC boost charging parameter configuration stage is as follows, including:

[0107] Step S201: The DC charging pile control module inputs the DC charging pile insulation detection completion status;

[0108] Step S202: After the insulation test is completed, the vehicle sends the current battery voltage U1 to the DC charging pile;

[0109] Step S203: The DC charging state control module determines whether the maximum output capacity of the DC charging pile is received. If so, it proceeds to step S204; if not, it returns to step S202;

[0110] Step S204: Control the boost charging relay to close and complete the high voltage power-on operation;

[0111] Step S205: The DC charging state control module 9 requests the energy conversion device to enter the voltage reduction mode and requests to reduce the voltage to U1. The electric drive charging boost coordination module 10 responds to the instruction and performs the voltage reduction operation;

[0112] Step S206: The DC charging state control module 9 determines whether the voltage reduction is completed. If it is completed, it goes to step S207, otherwise it returns to step S205;

[0113] Step S207: Inform the DC charging pile that the vehicle is ready.

[0114] In this embodiment, Figure 4 As shown in FIG. 1 , the process of the charging phase using the boost charging circuit includes:

[0115] Step S301: perform parameter configuration;

[0116] Step S302: After confirming that the parameter configuration is complete, the DC charging state control module 9 requests the energy conversion device to enter the boost mode, and the electric drive charging boost coordination module 10 responds to the instruction;

[0117] Step S303: The DC charging state control module 9 determines whether the maximum output voltage of the DC charging pile is less than or equal to a preset value (500V); if not, proceed to step S304; if yes, proceed to step S305 and step S306;

[0118] Step S304: Jump to the DC charging process;

[0119] Step S305: Send the required voltage U1 and the required current I1 to the DC charging pile, and proceed to step S307;

[0120] Step S306: Send the required voltage U to the energy conversion device req , the required current is I req ;

[0121] Step S307: The DC charging state control module 9 determines the output current of the DC charging pile. If the DC charging pile has output current, the process proceeds to step S308, otherwise, the process returns to step S305;

[0122] Step S308: the required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1;

[0123] Step S309: The DC charging state control module 9 determines whether the required voltage sent to the DC charging pile rises to U2. If so, it proceeds to step S310, otherwise it returns to step S308;

[0124] Step S310: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is to slowly increase the current from I1 to I2 at a preset rate;

[0125] Step S311: The system enters a normal boost charging state.

[0126] In this embodiment, Figure 5 As shown, the process of charging using a DC charging circuit is as follows, including:

[0127] Step S401: configure charging parameters;

[0128] Step S402: After confirming that the parameter configuration is complete, the DC charging state control module 9 requests the energy conversion device to enter the boost mode, and the electric drive charging boost coordination module 10 responds to the instruction;

[0129] Step S403: The DC charging state control module 9 determines whether the maximum output voltage of the DC charging pile is greater than a preset value. If the maximum output voltage of the DC charging pile is greater than 500V, the process proceeds to step S405 and step S406; otherwise, the process proceeds to step S404;

[0130] Step S404: Jump to the boost charging process;

[0131] Step S405: Sending the required voltage U1 and the required current I1 to the DC charging pile, and proceeding to step S407;

[0132] Step S406: Send the required voltage U to the energy conversion device req , the required current is I req , and proceed to step S415;

[0133] Step S407: The DC charging state control module 9 determines whether the DC charging pile outputs current. If the DC charging pile outputs current, the process proceeds to step S408; otherwise, the process returns to step S405.

[0134] Step S408: The required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1;

[0135] Step S409: the DC charging state control module 9 determines whether the required voltage rises to U2, if so, proceeds to step S410, otherwise returns to step S408;

[0136] Step S410: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is I3;

[0137] Step S411: The DC charging state control module 9 determines the output current of the DC charging pile. If the output current of the DC charging pile drops to I3, the process proceeds to step S412, otherwise, the process returns to step S410;

[0138] Step S412: closing the DC charging relay and disconnecting the boost charging relay;

[0139] Step S413: Sending a required voltage U to the DC charging pile req , the demand current is I2;

[0140] Step S414: the system enters a normal DC charging state;

[0141] Step S415: the DC charging state control module 9 determines the state of the boost charging relay. If the boost charging relay is disconnected, proceed to step S416, otherwise, return to step S406;

[0142] Step S416: turning off the output of the energy conversion device;

[0143] Step S417: Control the energy conversion device to enter the no-request mode.

[0144] In this embodiment, the value of U1 is the smaller value of the minimum total discharge voltage of the battery minus the first offset (calibrated value) and the maximum output voltage of the DC charging pile. The purpose of the minimum total discharge voltage of the battery minus the first offset is to ensure that the output voltage of the DC charging pile is lower than the battery voltage so that the energy conversion device can be used for boost charging; the purpose of taking the smaller value of the maximum output voltage of the DC charging pile is to ensure that the battery voltage is within the range allowed by the DC charging pile each time to prevent the DC charging pile from reporting a charging parameter mismatch fault.

[0145] The value of I1 is the smaller of the allowable charging current and the safe charging current of the battery. The purpose is to ensure that when the DC charging pile adjusts the output voltage quickly, the voltage will not be unstable due to excessive current, and the safe current can be calibrated.

[0146] The value of U2 is: the smaller of the current total voltage of the battery minus the second offset (calibrated value) and the maximum output voltage of the DC charging pile.

[0147] The value of I2 is: the battery allows charging current.

[0148] U req The value is: total battery voltage plus the third offset (calibrated value).

[0149] I req The values ​​are:

[0150] The value of I3 is: the minimum output current of the DC charging pile, where BCL is the code specified by the national standard, which refers to the charging demand sent by the battery to the DC charging pile.

[0151] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A DC boost charging control system for electric vehicles, characterized in that: It includes a charging mode recognition module (1), a power battery control module (2), an electric system capacity estimation module (3), a charging port temperature acquisition module (4), a charging parameter configuration module (5), a DC charging pile control module (6), a relay control module (7), a vehicle charging condition judgment module (8), a DC charging state control module (9), an electric drive charging boost coordination module (10) and an execution electronic control (11); The charging mode identification module (1) is used to determine whether the current charging mode is a DC charging mode or an AC charging mode after the CC signal is connected; The power battery control module (2) is used to monitor and feedback the battery current, the highest cell voltage, the lowest cell voltage, the highest cell temperature, the lowest cell temperature, the average temperature and the battery heating demand, and calculate and feedback the current allowable charging capacity of the battery; The electric system capacity estimation module (3) is used to calculate and feed back the sum of the actual power consumption of the high-voltage load, and the electric system capacity estimation module (3) is connected to the charging mode identification module (1); The charging port temperature collection module (4) is used to collect the temperature of the charging plug socket; The charging parameter configuration module (5) is used to calculate the required voltage and required current during external charging according to the power supply system, the temperature limit coefficient and the battery demand, and the charging parameter configuration module (5) is respectively connected to the power battery control module (2), the electric system capacity estimation module (3) and the charging port temperature acquisition module (4); The DC charging pile control module (6) is used to collect the working voltage and current range of the DC charging pile; The relay control module (7) is used to control the closing and opening of each relay in the charging circuit; The vehicle charging condition judgment module (8) is used to judge the conditions under which the vehicle is allowed to charge or prohibited to charge, and to feed back the judgment result; The DC charging state control module (9) parses the signals and instructions fed back by the charging mode identification module (1), the power battery control module (2), the electric system capacity estimation module (3), the charging port temperature acquisition module (4), the charging parameter configuration module (5), the DC charging pile control module (6), the relay control module (7), and the vehicle charging condition judgment module (8) into corresponding electric drive charging voltage conversion mode requests and sends them to the electric drive charging boost coordination module (10), and is also responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the highest output voltage of the DC charging pile is less than or equal to a preset value, the control system enters the boost charging flow The control system enters the DC charging process and sends a required voltage U1 and a required current I1 to the DC charging pile; if the highest output voltage received from the DC charging pile is greater than a preset value, the control system enters the DC charging process and sends a required voltage U1 and a required current I1 to the DC charging pile; the DC charging state control module (9) is respectively connected to the charging parameter configuration module (5), the DC charging pile control module (6), the relay control module (7), and the vehicle charging condition judgment module (8); wherein the value of U1 is the smaller value of the minimum total discharge voltage of the battery minus the first offset and the maximum output voltage of the DC charging pile; and the value of I1 is the smaller value of the allowable charging current of the battery and the safe charging current; The electric drive charging voltage boost coordination module (10) enters a corresponding mode according to an electric drive charging voltage transformation mode request sent by a DC charging state control module (9) and controls the execution electronic control (11) to perform a corresponding action. The electric drive charging voltage boost coordination module (10) is respectively connected to the DC charging state control module (9) and the execution electronic control (11).

2. A DC boost charging control method for electric vehicles, connecting the vehicle end with a DC charging pile; wherein: The vehicle end includes a power battery, a main positive relay, a pre-charging relay, a pre-charging resistor, a charging positive relay, an energy conversion device, a charging port capacitor, a boost charging relay and a DC charging relay. The positive end of the power battery is connected to the energy conversion device and one end of the charging positive relay respectively through the main positive relay, and the other end of the charging positive relay is connected to the energy conversion device and one end of the boost charging relay respectively through the charging port capacitor. The other end of the boost charging relay is connected to the negative end of the power battery through the DC charging relay. The pre-charging relay and the pre-charging resistor are connected in series and then connected in parallel with the main positive relay. It is characterized in that: the vehicle end is also integrated with the electric vehicle DC boost charging control system as claimed in claim 1, and its control method includes: The charging mode identification module (1) determines whether the current charging mode is a DC charging mode or an AC charging mode according to the CC signal access; The power battery control module (2) monitors and feeds back the battery current, the highest cell voltage, the lowest cell voltage, the highest cell temperature, the lowest cell temperature, the average temperature and the battery heating demand, and calculates and feeds back the current allowable charging capacity of the battery; The electrical system capacity estimation module (3) calculates and feeds back the sum of the actual power consumption of the high voltage load; The charging port temperature collection module (4) collects the temperature of the charging plug socket; The charging parameter configuration module (5) calculates the required voltage and required current during external charging according to the power supply system, temperature limit coefficient and battery requirements; The DC charging pile control module (6) collects the operating voltage and current range of the DC charging pile; The vehicle charging condition judgment module (8) judges the conditions for allowing or prohibiting charging of the vehicle, and feeds back the judgment result; The DC charging state control module (9) parses the signals and instructions fed back by the charging mode identification module (1), the power battery control module (2), the electric system capacity estimation module (3), the charging port temperature acquisition module (4), the charging parameter configuration module (5), the DC charging pile control module (6), the relay control module (7), and the vehicle charging condition judgment module (8) into corresponding electric drive charging voltage conversion mode requests, and sends them to the electric drive charging boost coordination module (10), and is also responsible for the communication interaction between the vehicle and the DC charging pile during the entire DC boost charging process; if the maximum output voltage of the DC charging pile received is less than or equal to the preset value, the control system enters the boost charging process; if the maximum output voltage of the DC charging pile received is greater than the preset value, the control system enters the DC charging process; The electric drive charging voltage boost coordination module (10) enters a corresponding mode according to the electric drive charging voltage transformation mode request sent by the DC charging state control module (9) and controls the execution electronic control (11) to perform corresponding actions.

3. The electric vehicle DC boost charging control method according to claim 2, characterized in that: The boost charging process is specifically as follows: Step 301: configure charging parameters; Step S302: after confirming that the parameter configuration is complete, the DC charging state control module (9) requests the energy conversion device to enter a boost mode, and the electric drive charging boost coordination module (10) responds to the instruction; Step S303: The DC charging state control module (9) determines whether the maximum output voltage of the DC charging pile is less than or equal to a preset value; if not, proceed to step S304; if yes, proceed to step S305 and step S306; Step S304: Jump to the DC charging process; Step S305: Send the required voltage U1 and the required current I1 to the DC charging pile, and proceed to step S307; Step S306: Send the required voltage U to the energy conversion device req , the required current is I req ; Step S307: The DC charging state control module (9) determines the output current of the DC charging pile. If the DC charging pile has output current, the process proceeds to step S308; otherwise, the process returns to step S305. Step S308: the required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1; Step S309: The DC charging state control module (9) determines whether the required voltage sent to the DC charging pile rises to U2. If so, it proceeds to step S310, otherwise it returns to step S308; Step S310: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is to slowly increase the current from I1 to I2 at a preset rate; Step S311: The system enters a normal boost charging state.

4. The electric vehicle DC boost charging control method according to claim 3, characterized in that: The DC charging process is specifically as follows: Step S401: configure charging parameters; Step S402: After confirming that the parameter configuration is complete, the DC charging state control module (9) requests the energy conversion device to enter a boost mode, and the electric drive charging boost coordination module (10) responds to the instruction; Step S403: The DC charging state control module (9) determines whether the maximum output voltage of the DC charging pile is greater than a preset value. If the maximum output voltage of the DC charging pile is greater than the preset value, the process proceeds to step S405 and step S406; otherwise, the process proceeds to step S404. Step S404: Jump to the boost charging process; Step S405: Sending the required voltage U1 and the required current I1 to the DC charging pile, and proceeding to step S407; Step S406: Send the required voltage U to the energy conversion device req , the required current is I req , and proceed to step S415; Step S407: The DC charging state control module (9) determines whether the DC charging pile outputs current. If the DC charging pile outputs current, the process proceeds to step S408; otherwise, the process returns to step S405. Step S408: The required voltage sent to the DC charging pile is increased to U2 at a faster rate, and the required current is I1; Step S409: The DC charging state control module (9) determines whether the required voltage rises to U2, if so, proceeds to step S410, otherwise returns to step S408; Step S410: the required voltage sent to the DC charging pile reaches U2, and the required current sent to the DC charging pile is I3; Step S411: The DC charging state control module (9) determines the output current of the DC charging pile. If the output current of the DC charging pile drops to I3, the process proceeds to step S412; otherwise, the process returns to step S410. Step S412: closing the DC charging relay and disconnecting the boost charging relay; Step S413: Sending a required voltage U to the DC charging pile req , the demand current is I2; Step S414: the system enters a normal DC charging state; Step S415: the DC charging state control module (9) determines the state of the boost charging relay. If the boost charging relay is disconnected, proceed to step S416; otherwise, return to step S406; Step S416: turning off the output of the energy conversion device; Step S417: Control the energy conversion device to enter the no-request mode.

5. The electric vehicle DC boost charging control method according to claim 4, characterized in that: The process of configuring the charging parameters includes: Step S201: the DC charging pile control module (6) inputs the DC charging pile insulation detection completion status; Step S202: After the insulation test is completed, the vehicle sends the current battery voltage U1 to the DC charging pile; Step S203: The DC charging state control module (9) determines whether the maximum output capacity of the DC charging pile is received, if so, proceeds to step S204, if not, returns to step S202; Step S204: Control the boost charging relay to close and complete the high voltage power-on operation; Step S205: the DC charging state control module (9) requests the energy conversion device to enter the voltage reduction mode and requests to reduce the voltage to U1, and the electric drive charging boost coordination module (10) responds to the instruction and performs the voltage reduction operation; Step S206: The DC charging state control module (9) determines whether the voltage reduction is completed. If it is completed, the process proceeds to step S207; otherwise, the process returns to step S205; Step S207: Inform the DC charging pile that the vehicle is ready.

6. The electric vehicle DC boost charging control system according to claim 5, characterized in that: The value of U2 is the smaller value of the current total voltage of the battery minus the second offset and the maximum output voltage of the DC charging pile; the value of I2 is the allowable charging current of the battery.

7. The electric vehicle DC boost charging control system according to claim 3, 4, 5 or 6, characterized in that: The U req The value of is the total battery voltage plus the third offset; I req The value of 8. The control method of the electric vehicle DC boost charging control system according to claim 4 or 5, characterized in that: The value of I3 is the minimum output current of the DC charging pile.

9. A vehicle, characterized in that: The electric vehicle DC boost charging control system as claimed in claim 1 is adopted.

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