Pre-charging control method and device and vehicle
By monitoring the bus voltage rise rate and optimizing the duty cycle, the target pre-charge voltage is accurately determined, solving the problem of overcharging or undercharging during the pre-charge process, improving charging efficiency and safety, reducing energy loss, and ensuring battery stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-27
- Publication Date
- 2026-04-07
AI Technical Summary
In the existing pre-charging process, the target voltage for pre-charging is not accurate enough, leading to frequent overcharging or undercharging, which affects the performance of the power battery and the vehicle's battery management system.
The pre-charge target voltage is determined by monitoring the rise rate of the bus voltage, and the pre-charge control is optimized based on the optimal duty cycle and objective function. A pre-charge loop is constructed to minimize the pre-charge duration and equivalent impedance, thereby optimizing the pre-charge process.
It achieves precision and safety in the pre-charging process, improves charging efficiency, reduces energy loss, avoids damage to the circuit from capacitor surge current, and ensures battery safety and performance.
Smart Images
Figure CN121799223A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle technology, and more particularly to the field of power battery technology, specifically to a pre-charging control method, device, and vehicle. Background Technology
[0002] Currently, the market for new energy vehicles is booming, and more and more new energy vehicles are entering people's lives. When the power battery of a new energy vehicle experiences a depletion of power, it needs to be charged promptly using a charging station to avoid affecting travel. However, directly using a charging station with its high voltage output can affect the performance of the power battery and the vehicle's battery management system. Therefore, pre-charging is necessary before formal charging to allow the voltage in the charging circuit to rise slowly, thereby avoiding safety risks.
[0003] Current pre-charging processes typically use a fixed differential voltage threshold for pre-charging judgment, without considering the actual state of the battery, which can lead to overcharging or undercharging. Therefore, a more effective pre-charging control method is urgently needed to control the pre-charging of power batteries. Summary of the Invention
[0004] This application provides a pre-charging control method, apparatus, and vehicle to at least solve the technical problem in related technologies where the pre-charging target voltage is not accurate enough, leading to overcharging or undercharging during the pre-charging process. The technical solution adopted in this application is as follows: In a first aspect, this application provides a pre-charge control method applied to a pre-charge loop, which is used to pre-charge the DC bus capacitor to increase the DC bus voltage. The method includes: during the pre-charge process, in response to the DC bus voltage rise rate being lower than a preset rise rate, determining the corresponding pre-charge target voltage for the DC bus; determining the optimal duty cycle of the pre-charge relay in the pre-charge loop based on the pre-charge target voltage and an objective function; wherein the objective function is constructed with the goal of minimizing the pre-charge duration and the equivalent impedance of the DC bus capacitor; and performing pre-charge control based on the optimal duty cycle.
[0005] Based on the aforementioned technical means, this application determines the pre-charge target voltage by monitoring the rise rate of the bus voltage, enabling the determined pre-charge target voltage to more accurately adapt to different pre-charge conditions and ensuring a safer pre-charge process for the battery. Constructing an objective function with the goals of minimizing the pre-charge duration and minimizing the equivalent impedance of the DC bus capacitor can improve pre-charge efficiency by shortening the pre-charge duration and reduce energy loss by reducing impedance. Furthermore, optimizing the duty cycle to optimize the pre-charge duration and the equivalent impedance of the DC bus capacitor can effectively suppress capacitor inrush current and avoid damage to the capacitor and pre-charge circuit from large currents, thereby improving charging performance.
[0006] In one possible implementation, the objective function is constructed with the goal of minimizing the precharge duration, the equivalent impedance, and the first voltage difference between the precharge target voltage and the expected voltage of the DC bus at the end of the precharge.
[0007] Based on the above technical means, this application can improve the charging efficiency of pre-charging by minimizing the pre-charging time, reduce the energy loss in the pre-charging circuit by minimizing the equivalent impedance, thereby improving energy utilization, and control the first voltage difference can make the DC bus voltage reach the expected voltage more accurately, avoiding overvoltage or undervoltage. Constructing the objective function with minimizing the pre-charging time, equivalent impedance, and first voltage difference as the objectives can make the optimization objectives of the objective function more comprehensive.
[0008] In one possible implementation, the objective function needs to satisfy the constraint that the bus voltage is maintained within a preset voltage range. The preset voltage range is determined based on the allowable voltage fluctuation range and the terminal voltage of the battery in the pre-charge circuit. The allowable voltage fluctuation range is used to prevent pre-charge overvoltage or pre-charge undervoltage.
[0009] Based on the above technical means, this application can avoid the pre-charge overvoltage state caused by excessive bus voltage or the pre-charge undervoltage state caused by excessive bus voltage by setting the constraint conditions of the objective function.
[0010] In one possible implementation, determining the pre-charge target voltage corresponding to the DC bus includes: determining a pre-charge voltage correction factor based on the current equivalent impedance of the DC bus capacitance; wherein the equivalent impedance is determined by the current duty cycle of the pre-charge relay in the pre-charge circuit; and determining the pre-charge target voltage based on the terminal voltage and the voltage correction factor.
[0011] Based on the above technical means, the terminal voltage of this application can reflect the current voltage state of the DC bus, and the voltage correction coefficient can take into account the influence of equivalent impedance on the circuit voltage. Based on this, the pre-charge target voltage can be determined by the terminal voltage and the voltage correction coefficient related to the current equivalent impedance, which can reduce the inaccuracy of the pre-charge target voltage setting caused by ignoring information such as equivalent impedance.
[0012] In one possible implementation, the voltage correction factor for pre-charging is determined based on the current equivalent impedance of the DC bus capacitor, including: determining the voltage correction factor based on the current parameter values of the battery state parameters at the battery terminal and the current equivalent impedance; wherein, the battery state parameters include, but are not limited to: battery state of charge and battery temperature.
[0013] Based on the above technical means, this application can take into account the influence of the remaining battery charge on the voltage by determining the voltage correction coefficient through the battery state of charge, and can compensate for the voltage fluctuation caused by temperature changes by determining the voltage correction coefficient through the battery temperature. The voltage correction coefficient of the pre-charge target voltage can be determined based on the battery state of charge, battery temperature, and current equivalent impedance, which can improve the voltage rationality of the pre-charge target voltage.
[0014] In one possible implementation, the voltage correction coefficient is determined based on the current parameter values of the battery state parameters and the current equivalent impedance at the battery terminal. This includes: determining the voltage correction coefficient based on a first correction coefficient corresponding to the current parameter value and a second correction coefficient corresponding to the current equivalent impedance; wherein the first correction coefficient is determined based on a third correction coefficient corresponding to the current battery state of charge and a fourth correction coefficient corresponding to the current battery temperature; the current equivalent impedance is positively correlated with the second correction coefficient; the current battery state of charge is negatively correlated with the third correction coefficient; and the current battery temperature is positively correlated with the fourth correction coefficient.
[0015] According to the above technical means, the larger the equivalent impedance of this application, the greater the voltage loss generated in the circuit. To compensate for the voltage loss caused by impedance, the second correction coefficient needs to be increased. When the state of charge is large, the battery itself is in a high-charge state. If the pre-charge target voltage is set too high, it will damage the battery. Therefore, the third correction coefficient needs to be reduced to lower the pre-charge target voltage and reduce battery damage. The further the battery temperature deviates from the suitable temperature range, the more the battery performance will be affected when the battery temperature is too high or too low, resulting in a voltage drop. Based on this, the fourth correction coefficient is increased to compensate for the voltage drop caused by excessively high or low temperatures. By correcting the pre-charge target voltage based on the second, third, and fourth correction coefficients, the pre-charge target voltage can be adjusted more comprehensively and accurately to effectively prevent insufficient or excessive pre-charge.
[0016] In one possible implementation, the pre-charge control method further includes: re-determining the optimal duty cycle in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds; performing pre-charge control based on the re-determined optimal duty cycle; and stopping pre-charge in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds after performing pre-charge control based on the re-determined optimal duty cycle.
[0017] Based on the above technical means, this application compares the parameter values of the battery state parameters and / or the equivalent impedance of the DC bus capacitor with their respective safety thresholds. When the parameter values and equivalent impedance exceed their respective safety thresholds, it indicates that there is an abnormality in the pre-charging circuit. Based on this, the optimal duty cycle is adjusted to intervene in the pre-charging process in a timely manner, avoiding overcharging or undercharging due to abnormal conditions, and ensuring the safety of the battery and capacitor.
[0018] In one possible implementation, the pre-charge control method further includes: switching the communication protocol of the pre-charge conversion message when the communication duration of the pre-charge conversion message is greater than a first preset duration; and stopping pre-charging if the communication duration of the pre-charge conversion message is still greater than the second preset duration within a second preset duration after the communication protocol is implemented.
[0019] According to the above technical means, if the communication duration of the precharge conversion message is longer than the first preset duration, it indicates that the current communication protocol cannot meet the protocol adaptation of precharge and it is necessary to change the communication protocol to avoid the inability to perform effective precharge due to protocol failure.
[0020] In one possible implementation, the pre-charge control method further includes: in response to receiving a pre-charge command, starting pre-charge control with the duty cycle of the pre-charge relay in the pre-charge circuit as the default duty cycle.
[0021] Based on the above technical means, this application enables pre-charge control with a default duty cycle when pre-charge is enabled, which can provide relatively stable initial pre-charge control when pre-charge is just enabled, thereby avoiding excessive current surges or slow charging caused by excessively large or small duty cycles.
[0022] In one possible implementation, the pre-charge control method further includes: stopping the pre-charge control in response to a second voltage difference between the main positive relay and the main negative relay of the pre-charge circuit not being greater than a preset voltage difference.
[0023] According to the above technical means, when the second voltage difference of this application is not greater than the preset voltage difference, it indicates that the DC bus voltage and the battery voltage are basically balanced. Based on this, the pre-charge control is terminated and the charging control process is carried out, which can avoid the problem of poor charging stability caused by voltage fluctuations and improve the charging performance of the battery.
[0024] Secondly, this application provides a pre-charge control device applied to a pre-charge circuit. The pre-charge circuit is used to pre-charge the DC bus capacitor to increase the DC bus voltage. The device includes: a voltage determination module, used to determine a pre-charge target voltage for the DC bus during the pre-charge process, in response to the DC bus voltage rise rate being lower than a preset rise rate; a duty cycle determination module, used to determine the optimal duty cycle of the pre-charge relay in the pre-charge circuit based on the pre-charge target voltage and an objective function; wherein the objective function is constructed with the goal of minimizing the pre-charge duration and the equivalent impedance of the DC bus capacitor; and a pre-charge control module, used to perform pre-charge control based on the optimal duty cycle.
[0025] In one possible implementation, the objective function is constructed with the goal of minimizing the precharge duration, the equivalent impedance, and the first voltage difference between the precharge target voltage and the expected voltage of the DC bus at the end of the precharge.
[0026] In one possible implementation, the objective function needs to satisfy the constraint that the bus voltage is maintained within a preset voltage range. The preset voltage range is determined based on the allowable voltage fluctuation range and the terminal voltage of the battery in the pre-charge circuit. The allowable voltage fluctuation range is used to prevent pre-charge overvoltage or pre-charge undervoltage.
[0027] In one possible implementation, a voltage determination module is used to determine a pre-charge voltage correction factor based on the current equivalent impedance of the DC bus capacitor; wherein the equivalent impedance is determined by the current duty cycle of the pre-charge relay in the pre-charge circuit; and the pre-charge target voltage is determined based on the terminal voltage and the voltage correction factor.
[0028] In one possible implementation, the voltage determination module is further configured to determine a voltage correction coefficient based on the current parameter values of the battery state parameters and the current equivalent impedance at the battery terminal; wherein the battery state parameters include, but are not limited to, the battery state of charge and the battery temperature.
[0029] In one possible implementation, the voltage determination module is specifically used to determine the voltage correction coefficient based on a first correction coefficient corresponding to the current parameter value and a second correction coefficient corresponding to the current equivalent impedance; wherein, the first correction coefficient is determined based on a third correction coefficient corresponding to the current battery state of charge and a fourth correction coefficient corresponding to the current battery temperature; the current equivalent impedance is positively correlated with the second correction coefficient; the current battery state of charge is negatively correlated with the third correction coefficient; and the current battery temperature is positively correlated with the fourth correction coefficient.
[0030] In one possible implementation, the pre-charge control device is further configured to: re-determine the optimal duty cycle in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds; perform pre-charge control based on the re-determined optimal duty cycle; and after performing pre-charge control based on the re-determined optimal duty cycle, stop pre-charging in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
[0031] In one possible implementation, the precharge control device is further configured to switch the communication protocol of the precharge conversion message when the communication duration of the precharge conversion message is greater than a first preset duration; and to stop precharging if the communication duration of the precharge conversion message is still greater than the second preset duration within a second preset duration after the communication protocol is implemented.
[0032] In one possible implementation, the aforementioned pre-charge control device is further configured to, in response to receiving a pre-charge command, activate pre-charge control with the duty cycle of the pre-charge relay in the pre-charge circuit as the default duty cycle.
[0033] In one possible implementation, the pre-charge control device is further configured to stop pre-charge control in response to a second voltage difference between the main positive relay and the main negative relay of the pre-charge circuit not being greater than a preset voltage difference.
[0034] Thirdly, this application provides a vehicle including a power battery, wherein the power battery uses the pre-charge control device described in the second aspect to control the pre-charge voltage.
[0035] Fourthly, this application provides an electronic device, including: a processor and a memory, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by the processor to implement the method described in the first aspect and any possible implementation thereof.
[0036] Fifthly, this application provides a computer-readable storage medium that, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the methods described in the first aspect and any possible implementation thereof.
[0037] In a sixth aspect, this application provides a computer program product comprising computer instructions that, when executed on an electronic device, cause the electronic device to perform the method described in the first aspect and any of its possible implementations.
[0038] It should be noted that the technical effects of any of the implementation methods in aspects two through six can be found in the technical effects of the corresponding implementation methods in aspect one, and will not be repeated here.
[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application, and do not constitute an undue limitation of this application.
[0041] Figure 1 This is a schematic diagram illustrating the application environment of a pre-charging control device according to an embodiment of this application; Figure 2 This is a flowchart illustrating a pre-charge control method according to an embodiment of this application; Figure 3 This is a flowchart illustrating a fault handling method according to an embodiment of this application; Figure 4 This is a flowchart illustrating another fault handling method shown in an embodiment of this application; Figure 5 This is a flowchart illustrating another pre-charge control method shown in an embodiment of this application; Figure 6 This is a block diagram illustrating a pre-charging control device according to an embodiment of this application; Figure 7 This is a block diagram illustrating an electronic device according to an embodiment of this application. Detailed Implementation
[0042] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.
[0043] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0044] In the embodiments of this application, the words "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the words "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a specific manner.
[0045] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0046] The pre-charge control device provided in this application embodiment is used for pre-charging control of the power battery of a vehicle (especially an intelligent driving vehicle). A vehicle can also be referred to as a vehicle, mobile carrier, electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), fuel cell vehicle (FCV), autonomous vehicle, intelligent and connected vehicle (ICV), driverless vehicle, etc.
[0047] In this application, the vehicle can be a sedan, a sport utility vehicle (SUV), a truck, a special vehicle (such as an ambulance, fire truck, police car, etc.), a driverless taxi, a smart connected bus, an autonomous logistics vehicle, an electric truck, etc. Furthermore, this method is also applicable to various special-purpose vehicles, such as agricultural vehicles, mining vehicles, forestry vehicles, airport vehicles, and port vehicles. This application does not impose specific limitations in this regard.
[0048] Figure 1 This is a schematic diagram illustrating the application environment of a pre-charging control device according to an embodiment of this application.
[0049] In one possible implementation, such as Figure 1 As shown, the above application environment includes vehicle 101 and power supply equipment 102.
[0050] The vehicle 101 includes a pre-charging control device 1001 and a data acquisition device 1002.
[0051] The data acquisition device 1002 includes a battery voltage sensor, a temperature sensor, and a relay status sensor, etc.
[0052] The data acquisition device 1002 is used to collect the state parameters of the power battery, such as the battery state of charge value, bus voltage, voltage across the fast charging positive relay and voltage across the fast charging negative relay, and transmit them to the pre-charge control device 1001.
[0053] The pre-charge control device 1001 is used to receive the bus voltage collected by the data acquisition device 1002, and determine the pre-charge target voltage of the DC bus when the voltage rise rate of the bus voltage is lower than the preset rise rate.
[0054] The precharge control device 1001 is also used to determine the optimal duty cycle of the precharge relay in the precharge circuit based on the precharge target voltage and the objective function.
[0055] The pre-charge control device 1001 is also used to perform pre-charge control of the vehicle 101 according to the optimal duty cycle when the power supply equipment 102 is charging the vehicle 101.
[0056] The aforementioned vehicle 101 also includes a protocol conversion device, which integrates CAN and PLC dual communication interfaces to automatically convert between Chinese and European standard messages.
[0057] As one possible approach, the dynamic conversion module in the aforementioned protocol conversion device communicates with the power supply equipment 102 via power line carrier communication (PLC) during European standard charging, and forwards data to the vehicle's battery management system (BMS) in real time via CAN communication.
[0058] The vehicle 101 also includes a communication controller. After the charging gun of the power supply device 102 is inserted into the vehicle 101, the communication controller is used to simulate the CC2 plug-in signal and the A+ wake-up signal.
[0059] The communication controller is also used to complete connection tests between the PLC and the power supply equipment 102 via power line carrier communication.
[0060] In practical applications, the data acquisition device 1002 can communicate with one or more pre-charge control devices 1001.
[0061] For ease of understanding, this application uses the example of a data acquisition device 1002 communicating with a pre-charge control device 1001 for illustration.
[0062] As a feasible approach, Figure 1The pre-charging control device 1001 and the data acquisition device 1002 are installed in the vehicle 101, and the pre-charging control device 1001 and the data acquisition device 1002 are independently installed devices. This application does not limit the comparison.
[0063] As a feasible approach, Figure 1 The pre-charge control device 1001 can be installed in a terminal, a server, or other types of electronic devices.
[0064] When the pre-charging control device 1001 is located at a terminal, the terminal can be a device providing data connectivity to vehicle users or vehicle owners, a handheld device with wireless connectivity, or other processing devices connected to a wireless modem. The terminal can communicate with one or more core networks via a radio access network (RAN). The terminal can be a mobile terminal, such as a computer with a mobile terminal, or a mobile device that exchanges voice and / or data with the radio access network, such as a mobile phone, tablet, laptop, netbook, or personal digital assistant (PDA). This application does not impose any limitations on this.
[0065] When the pre-charging control device 1001 is installed on a server, the server can be a single server or a server cluster consisting of multiple servers. In some embodiments, the server cluster can also be a distributed cluster. This application does not impose any limitations on this.
[0066] It should be noted that the structure illustrated in the embodiments of this application does not constitute a limitation on the pre-charge control device 1001. It may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of both.
[0067] For ease of understanding, the pre-charging control method provided in this application will be described in detail below with reference to the accompanying drawings.
[0068] Figure 2 This is a flowchart illustrating a pre-charge control method according to an embodiment of this application, referred to... Figure 2 This pre-charge control method is applied to a pre-charge circuit, which is used to pre-charge the DC bus capacitor to increase the DC bus voltage, including: The aforementioned pre-charge circuit is a circuit path designed to realize the battery pre-charge function. The pre-charge circuit includes components such as a power supply, a pre-charge relay, a resistor, and a DC bus capacitor. The power supply provides electrical energy, the pre-charge relay controls the on / off state of the pre-charge circuit, the resistor limits the magnitude of the pre-charge current, and the DC bus capacitor is the object being charged. Through the operation of the pre-charge circuit, the voltage across the DC bus capacitor is gradually increased, thereby increasing the DC bus voltage.
[0069] The aforementioned DC bus capacitor is a type of capacitor installed on the DC bus, used to store current, smooth DC bus voltage fluctuations, etc. During the pre-charging process, the DC bus capacitor acts as an energy storage element, absorbing electrical energy through the pre-charging circuit, causing the voltage across the DC bus capacitor to gradually increase, so as to obtain the final bus voltage.
[0070] The bus voltage mentioned above refers to the voltage value on the DC bus, which is a channel used for transmitting and distributing DC power.
[0071] S201. During the pre-charging process, in response to the DC bus voltage rise rate being lower than the preset rise rate, the pre-charging target voltage corresponding to the DC bus is determined.
[0072] The aforementioned pre-charging refers to the process of briefly charging the battery with a small current or a pulse current controlled by the duty cycle before charging the battery. The purpose of pre-charging is to allow the DC bus voltage to rise slowly, so as to approach the pre-charge target voltage, and to avoid the large inrush current generated by the excessive voltage difference between the DC bus and the battery during direct charging with a large current, which could damage the battery and circuit components such as relays.
[0073] As one possible approach, during the pre-charging process, the target pre-charge voltage can be set based on a preset percentage of the battery's rated voltage, for example, setting 90% of the battery voltage as the target pre-charge voltage.
[0074] As another possible implementation, during the pre-charging process, the voltage drop value of pre-charging is estimated based on the equivalent impedance of the DC bus capacitor, and the pre-charging target voltage is determined according to the battery rated voltage and the voltage drop value.
[0075] As another possible implementation, the pre-charge target voltage corresponding to the DC bus is determined by: determining the pre-charge voltage correction factor based on the current equivalent impedance of the DC bus capacitor; wherein the equivalent impedance is determined by the current duty cycle of the pre-charge relay in the pre-charge circuit; and determining the pre-charge target voltage based on the terminal voltage and the voltage correction factor.
[0076] The equivalent impedance mentioned above is used to reflect the capacitor's ability to impede current, in order to evaluate the battery's instantaneous response; an increase in equivalent impedance indicates that the equivalent impedance is in an aging or low-temperature state.
[0077] As one feasible approach, the equivalent impedance of the DC bus capacitor can be obtained based on the following formula: ; in, For equivalent impedance, The voltage difference between the positive and negative terminals of the pre-charge relay. This refers to the current flowing through the precharged relay.
[0078] The voltage correction factor mentioned above is used to characterize the influence of the equivalent impedance on the pre-charge target voltage. The larger the equivalent impedance, the larger the voltage correction factor.
[0079] The aforementioned precharge relay is a circuit control element that can control the on / off state of the precharge circuit. By controlling the on and off state of the precharge relay, the start, stop, and duty cycle adjustment of the precharge process can be achieved.
[0080] The duty cycle mentioned above refers to the ratio of the time the signal is at a high level to the total time of the cycle, which can be expressed as a percentage, fraction, etc. The cycle time refers to the time required for the signal to complete one full cycle from high level to low level.
[0081] The aforementioned terminal voltage refers to the voltage value between the current inflow end and the current outflow end. The essence of terminal voltage is the ratio of the work done by the electric field force to drive the movement of charges to the amount of charge.
[0082] S202. Determine the optimal duty cycle of the precharge relay in the precharge circuit based on the precharge target voltage and the objective function; wherein, the objective function is constructed with the goal of minimizing the precharge duration and the equivalent impedance of the DC bus capacitance.
[0083] The aforementioned pre-charge duration refers to the time interval between the start of battery pre-charge and the closing of the main positive relay.
[0084] As an achievable approach, the objective function is constructed with the goal of minimizing the precharge duration, equivalent impedance, and the first voltage difference between the precharge target voltage and the expected voltage of the DC bus at the end of the precharge.
[0085] As another feasible approach, the objective function is constructed with the goal of minimizing the precharge duration and the first voltage difference between the precharge target voltage and the expected voltage of the DC bus at the end of the precharge.
[0086] As another feasible approach, the objective function can also be constructed based on maximizing charging efficiency. For example, in a switching power supply, the power supply can usually operate with higher charging efficiency when the duty cycle is close to 0 or 1. Therefore, the pre-charge circuit can be made to operate in the corresponding range by adjusting the duty cycle.
[0087] As another feasible approach, the objective function can also be constructed based on the heat generated by the relay. For example, the objective can be to control the heat generated by the relay to be close to a preset temperature by adjusting the duty cycle.
[0088] In one possible implementation, the objective function needs to satisfy the constraint that the bus voltage is maintained within a preset voltage range. This preset voltage range is determined based on the allowable voltage fluctuation range and the terminal voltage at the battery terminals in the pre-charge circuit. The allowable voltage fluctuation range is used to prevent pre-charge overvoltage or pre-charge undervoltage. For example, the preset voltage range could be ±5% of the terminal voltage value.
[0089] S203. Pre-charge control is performed based on the optimal duty cycle.
[0090] As one possible approach, precharge control can be performed based on a default duty cycle, for example, a default duty cycle of 50%.
[0091] As an feasible approach, pre-charge control can be based on segmented duty cycles, dividing the pre-charge process into multiple pre-charge stages, each using a different duty cycle. For example, in the first stage, a higher duty cycle is used to rapidly increase the voltage; in the second stage, a medium duty cycle is used to charge smoothly; and in the third stage, a lower duty cycle is used to avoid overcharging. The first stage precedes the second stage, which in turn precedes the third stage. For instance, the higher duty cycle could be 70%, the medium duty cycle could be 50%, and the lower duty cycle could be 20%.
[0092] In one possible implementation, in response to receiving a pre-charge command, pre-charge control is activated with the duty cycle of the pre-charge relay in the pre-charge circuit as the default duty cycle, thereby avoiding excessive current surges or slow charging due to excessively large or small duty cycles.
[0093] The aforementioned pre-charge command is a control command used to indicate the start of the pre-charge operation.
[0094] The default duty cycle mentioned above refers to the duty cycle preset at the beginning of pre-charging, which serves as the initial parameter for pre-charging control to provide a suitable current in the early stages of pre-charging and ensure the stability of the pre-charging process. For example, the default duty cycle can be 50%.
[0095] Based on the aforementioned technical means, this application determines the pre-charge target voltage by monitoring the rise rate of the bus voltage, enabling the determined pre-charge target voltage to more accurately adapt to different pre-charge conditions and ensuring a safer pre-charge process for the battery. Constructing an objective function with the goals of minimizing the pre-charge duration and minimizing the equivalent impedance of the DC bus capacitor can improve pre-charge efficiency by shortening the pre-charge duration and reduce energy loss by reducing impedance. Furthermore, optimizing the duty cycle to optimize the pre-charge duration and the equivalent impedance of the DC bus capacitor can effectively suppress capacitor inrush current and avoid damage to the capacitor and pre-charge circuit from large currents, thereby improving charging performance.
[0096] In some embodiments, the voltage correction coefficient for pre-charging can also be determined based on the current parameter values of the battery state parameters and the current equivalent impedance at the battery terminal; wherein, the battery state parameters include, but are not limited to, the battery state of charge and the battery temperature.
[0097] As one possible approach, the voltage correction factor can be a single factor, namely a first voltage correction factor determined based on the current parameter value of the battery state parameters at the battery terminal and a second voltage correction factor determined based on the current equivalent impedance, with the average of the first and second voltage correction factors used as the voltage correction factor.
[0098] As another possible approach, the aforementioned voltage correction factor can be two factors: one determined based on the current value of the battery state parameters at the battery terminal, and another determined based on the current equivalent impedance. The pre-charge target voltage is then determined by multiplying these two voltage correction factors by the terminal voltage.
[0099] In one possible implementation, the voltage correction coefficient is determined based on the current parameter values of the battery state parameters and the current equivalent impedance at the battery terminal. This includes: determining the voltage correction coefficient based on a first correction coefficient corresponding to the current parameter value and a second correction coefficient corresponding to the current equivalent impedance; wherein the first correction coefficient is determined based on a third correction coefficient corresponding to the current battery state of charge and a fourth correction coefficient corresponding to the current battery temperature; the current equivalent impedance is positively correlated with the second correction coefficient; the current battery state of charge is negatively correlated with the third correction coefficient; and the current battery temperature is positively correlated with the fourth correction coefficient.
[0100] As one possible approach, the first correction factor can be determined by multiplying the coefficients of the third correction factor corresponding to the current battery state of charge and the fourth correction factor corresponding to the current battery temperature.
[0101] As another possible approach, the first correction factor can be determined based on the average of the coefficients of the third correction factor corresponding to the current battery state of charge and the fourth correction factor corresponding to the current battery temperature.
[0102] As another feasible approach, the voltage correction factor can be determined based on the average of the second, third, and fourth correction factors.
[0103] As another possible approach, the voltage correction factor can be determined based on the product of the second, third, and fourth correction factors.
[0104] The formula for calculating the voltage correction factor is as follows: ; in, This is the voltage correction factor. This is the second correction factor. This is the third correction factor. This is the fourth correction factor.
[0105] As an alternative approach, the second, third, and fourth correction coefficients can also be pre-set based on the prediction model.
[0106] Figure 3 This is a flowchart illustrating a fault handling method according to an embodiment of this application, with reference to... Figure 3 The fault handling method includes: S301. Monitor the parameter values of the battery status parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor.
[0107] S302. Determine whether the parameter values of the battery status parameters and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
[0108] For example, the safe threshold for the state of charge (SOC) parameter in battery status parameters can be 30%. That is, if the SOC parameter value is lower than 30%, it indicates that the SOC parameter value has exceeded the safe threshold.
[0109] If yes, then execute S303; otherwise, execute S301.
[0110] S303. Redetermine the optimal duty cycle.
[0111] As an option, if the battery's state of charge parameter exceeds a safety threshold, the pre-charge target voltage can be reduced to below the terminal voltage to avoid overcharging.
[0112] S304. Pre-charge control is performed based on the redefined optimal duty cycle.
[0113] S305. Determine whether the battery status parameters and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
[0114] If yes, then execute S306; otherwise, execute S307.
[0115] S306, Stop pre-charging.
[0116] S307, continue pre-charging.
[0117] As another possible approach Figure 4 This is a flowchart illustrating another fault handling method shown in the embodiments of this application, see below. Figure 4 The fault handling method includes: S401-S407.
[0118] S401, Monitor the communication duration of the precharge conversion message.
[0119] The aforementioned precharge transition message is a key control message in the electric vehicle charging communication protocol used to indicate the end of the precharge phase and trigger the closing of the main relay. Its core function is to achieve safe switching between the precharge circuit and the main circuit through standardized signals. For example, the types of precharge transition messages include battery charging demand messages or battery charging status messages.
[0120] The aforementioned precharge transition message typically includes key information such as capacitor voltage value and status code. The capacitor voltage value is used to confirm whether precharge is complete, while the status code indicates the status of the precharge transition.
[0121] S402. Determine whether the communication duration of the precharge conversion message is greater than the first preset duration.
[0122] If yes, then execute S403; otherwise, execute S401.
[0123] For example, the first preset duration can be set to 60 seconds.
[0124] S403, Communication protocol for switching precharge conversion messages.
[0125] The aforementioned communication protocols include European standard communication protocols and Chinese standard communication protocols, etc.
[0126] The aforementioned European standard communication protocol mainly uses power line carrier communication (PLC) technology to transmit data via high-frequency signals on power lines.
[0127] The aforementioned national standard communication protocol mainly uses CAN bus signals for control. Based on the preset national standard communication protocol, the communication rate is 250 kbit / s. The national standard communication protocol provides stable data transmission but has limited intelligent functions.
[0128] S404. Monitor the communication duration of the precharge conversion message after the switchover.
[0129] S405. Determine whether the communication duration of the precharge conversion message is greater than the second preset duration within the second preset duration after switching the communication protocol of the precharge conversion message.
[0130] As one possible approach, the second preset duration can be shorter than the first preset duration. For example, if the first preset duration is 5 seconds, the second preset duration can be set to 1 second.
[0131] If yes, then execute S406; otherwise, execute S407.
[0132] S406, Stop precharging.
[0133] S407, Continue pre-charging.
[0134] In one possible implementation, the pre-charge control method further includes: stopping the pre-charge control in response to a second voltage difference between the main positive relay and the main negative relay of the pre-charge circuit not being greater than a preset voltage difference, so as to improve the pre-charge efficiency.
[0135] As one feasible approach, if the second voltage difference between the main positive relay and the main negative relay in the pre-charge circuit is greater than a preset voltage difference, it indicates a significant voltage difference between the two relays. Based on this, closing the main positive relay would cause an arc discharge due to the high potential difference. Therefore, by setting a preset voltage difference to ensure that the voltage of the bus DC capacitor in the pre-charge circuit is close to the pre-charge target voltage, the potential difference can be eliminated.
[0136] As another possible implementation, the above-mentioned pre-charge control method further includes: stopping the pre-charge control when the voltage value of the main positive relay is greater than the voltage value of the main negative relay, in response to the voltage value of the main positive relay in the pre-charge circuit being greater than a first preset voltage value and / or the voltage value of the main negative relay being less than a second preset voltage value.
[0137] Figure 5 This is a flowchart illustrating another pre-charge control method according to an embodiment of this application. (Refer to...) Figure 5 The pre-charge control method includes: S501, Start the pre-charging process.
[0138] S502. Based on the current equivalent impedance of the DC bus capacitor and the current parameter values of the battery state parameters at the battery terminal, determine the voltage correction coefficient for pre-charging.
[0139] S503. Determine the pre-charge target voltage based on the terminal voltage and voltage correction coefficient.
[0140] S504. If the parameter values of the battery state parameters and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds, the optimal duty cycle shall be re-determined.
[0141] S505, Pre-charge control is performed based on the redefined optimal duty cycle.
[0142] S506. Determine whether the values of the battery status parameters and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
[0143] If yes, then execute S507; otherwise, execute S508.
[0144] S507, Stop pre-charging.
[0145] S508: Close the fast charging positive relay to complete the pre-charging.
[0146] Figure 6 This is a block diagram illustrating a pre-charge control device according to an embodiment of this application, with reference to... Figure 6 The pre-charge control device includes: a voltage determination module 601, a duty cycle determination module 602, and a pre-charge control module 603.
[0147] In one possible implementation, the objective function is constructed with the goal of minimizing the precharge duration, the equivalent impedance, and the first voltage difference between the precharge target voltage and the expected voltage of the DC bus at the end of the precharge.
[0148] In one possible implementation, the objective function needs to satisfy the constraint that the bus voltage is maintained within a preset voltage range. The preset voltage range is determined based on the allowable voltage fluctuation range and the terminal voltage of the battery in the pre-charge circuit. The allowable voltage fluctuation range is used to prevent pre-charge overvoltage or pre-charge undervoltage.
[0149] In one possible implementation, voltage determination module 601 is used to determine a pre-charge voltage correction factor based on the current equivalent impedance of the DC bus capacitor; wherein the equivalent impedance is determined by the current duty cycle of the pre-charge relay in the pre-charge circuit; and the pre-charge target voltage is determined based on the terminal voltage and the voltage correction factor.
[0150] In one possible implementation, the voltage determination module 601 is further configured to determine a voltage correction coefficient based on the current parameter values of the battery state parameters and the current equivalent impedance at the battery terminal; wherein the battery state parameters include, but are not limited to, the battery state of charge and the battery temperature.
[0151] In one possible implementation, the voltage determination module 601 is specifically used to determine a voltage correction coefficient based on a first correction coefficient corresponding to the current parameter value and a second correction coefficient corresponding to the current equivalent impedance; wherein, the first correction coefficient is determined based on a third correction coefficient corresponding to the current battery state of charge and a fourth correction coefficient corresponding to the current battery temperature; the current equivalent impedance is positively correlated with the second correction coefficient; the current battery state of charge is negatively correlated with the third correction coefficient; and the current battery temperature is positively correlated with the fourth correction coefficient.
[0152] In one possible implementation, the pre-charge control device is further configured to: re-determine the optimal duty cycle in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds; perform pre-charge control based on the re-determined optimal duty cycle; and after performing pre-charge control based on the re-determined optimal duty cycle, stop pre-charging in response to determining that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
[0153] In one possible implementation, the precharge control device is further configured to switch the communication protocol of the precharge conversion message when the communication duration of the precharge conversion message is greater than a first preset duration; and to stop precharging if the communication duration of the precharge conversion message is still greater than the second preset duration within a second preset duration after the communication protocol is implemented.
[0154] In one possible implementation, the aforementioned pre-charge control device is further configured to, in response to receiving a pre-charge command, activate pre-charge control with the duty cycle of the pre-charge relay in the pre-charge circuit as the default duty cycle.
[0155] In one possible implementation, the pre-charge control device is further configured to stop pre-charge control in response to a second voltage difference between the main positive relay and the main negative relay of the pre-charge circuit not being greater than a preset voltage difference.
[0156] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments of the pre-charge control method, and will not be elaborated upon here.
[0157] Figure 7 This is a block diagram illustrating an electronic device according to an embodiment of this application. Figure 7 As shown, the electronic device includes, but is not limited to, a processor 701 and a memory 702.
[0158] The memory 702 described above is used to store the executable instructions of the processor 701. It is understood that the processor 701 is configured to execute instructions to implement the vehicle operation control method in the above embodiments.
[0159] It should be noted that those skilled in the art will understand that Figure 7 The electronic device structure shown does not constitute a limitation on the electronic device; the electronic device may include, but is not limited to, other electronic devices. Figure 7 This may indicate more or fewer components, or combinations of certain components, or different component arrangements.
[0160] Processor 701 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in memory 702, and by calling data stored in memory 702, it performs various functions and processes data, thereby providing overall monitoring of the electronic device. Processor 701 may include one or more processing units. Processor 701 may integrate an application processor and a modem processor. The application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into processor 701.
[0161] The memory 702 can be used to store software programs and various data. The memory 702 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required by at least one functional module (such as deterministic components, integrated components, etc.), etc. Furthermore, the memory 702 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.
[0162] In an exemplary embodiment, a computer-readable storage medium including instructions is also provided, such as a memory 702 including instructions, which can be executed by a processor 701 of an electronic device to implement the methods in the above embodiments.
[0163] In actual implementation, Figure 6 The functions of the voltage determination module 601, duty cycle determination module 602, and pre-charge control module 603 can all be determined by... Figure 7 The processor 701 calls the computer program stored in the memory 702 to implement the process. The specific execution process can be found in the description of the method section in the previous embodiment, and will not be repeated here.
[0164] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium, such as a read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device. In an exemplary embodiment, this application also provides a computer program product including one or more instructions, which can be executed by the processor 701 of an electronic device to perform the methods in the above embodiments.
[0165] It should be noted that when one or more instructions in the computer-readable storage medium or computer program product are executed by the processor of an electronic device, they implement the various processes of the above method embodiments and achieve the same technical effect as the above method. To avoid repetition, they will not be described again here.
[0166] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.
[0167] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
[0168] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0169] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0170] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.
[0171] This application provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the methods described in the above method embodiments.
[0172] This application also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method in the method flow shown in the above method embodiments.
[0173] The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, a register, a hard disk, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof, or any other form of computer-readable storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an application-specific integrated circuit (ASIC). In embodiments of this application, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.
[0174] Since the pre-charge control device, computer-readable storage medium, and computer program product in the embodiments of this application can be applied to the above method, the technical effects that can be obtained can also be referred to the above method embodiments. The embodiments of this application will not be repeated here.
[0175] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A pre-charge control method, applied to a pre-charge circuit, wherein the pre-charge circuit is used to pre-charge the DC bus capacitor to increase the DC bus voltage, characterized in that, The pre-charge control method includes: During the pre-charging process, in response to the DC bus voltage rise rate being lower than the preset rise rate, the pre-charging target voltage corresponding to the DC bus is determined. The optimal duty cycle of the pre-charge relay in the pre-charge circuit is determined based on the pre-charge target voltage and the objective function; wherein, the objective function is constructed with the goal of minimizing the pre-charge duration and the equivalent impedance of the DC bus capacitor; Pre-charge control is performed based on the optimal duty cycle.
2. The pre-charge control method according to claim 1, characterized in that, The objective function is constructed with the goal of minimizing the pre-charge duration, the equivalent impedance, and the first voltage difference between the pre-charge target voltage and the expected voltage of the DC bus at the end of the pre-charge.
3. The pre-charge control method according to claim 1 or 2, characterized in that, The objective function needs to satisfy the constraint that the bus voltage is maintained within a preset voltage range. The preset voltage range is determined based on the allowable voltage fluctuation range and the terminal voltage of the battery in the pre-charge circuit; the allowable voltage fluctuation range is used to prevent pre-charge overvoltage or pre-charge undervoltage.
4. The pre-charge control method according to claim 3, characterized in that, Determining the pre-charge target voltage corresponding to the DC bus includes: The voltage correction factor for pre-charging is determined based on the current equivalent impedance of the DC bus capacitor; wherein the equivalent impedance is determined by the current duty cycle of the pre-charging relay in the pre-charging circuit. The pre-charge target voltage is determined based on the terminal voltage and the voltage correction coefficient.
5. The pre-charge control method according to claim 4, characterized in that, The determination of the pre-charge voltage correction factor based on the current equivalent impedance of the DC bus capacitor includes: The voltage correction coefficient is determined based on the current parameter values of the battery state parameters at the battery terminal and the current equivalent impedance. The battery state parameters include, but are not limited to, battery state of charge and battery temperature.
6. The pre-charge control method according to claim 5, characterized in that, The determination of the voltage correction coefficient based on the current parameter value of the battery state parameters at the battery terminal and the current equivalent impedance includes: The voltage correction coefficient is determined based on the first correction coefficient corresponding to the current parameter value and the second correction coefficient corresponding to the current equivalent impedance; The first correction factor is determined based on the third correction factor corresponding to the current battery state of charge and the fourth correction factor corresponding to the current battery temperature. The current equivalent impedance is positively correlated with the second correction factor; The current battery state of charge is negatively correlated with the third correction coefficient; The current battery temperature is positively correlated with the fourth correction factor.
7. The pre-charge control method according to claim 3, characterized in that, The pre-charge control method further includes: In response to the determination that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds, the optimal duty cycle is re-determined. Pre-charge control is performed based on the redefined optimal duty cycle; as well as After pre-charging control is performed based on the redefined optimal duty cycle, the pre-charging is stopped in response to the determination that the parameter values of the battery state parameters at the battery terminal and / or the equivalent impedance of the DC bus capacitor exceed their respective safety thresholds.
8. The pre-charge control method according to claim 3, characterized in that, The pre-charge control method further includes: If the communication duration of the precharge conversion message is greater than a first preset duration, the communication protocol of the precharge conversion message is switched. as well as, If, within a second preset time period following the communication protocol, the communication duration of the precharge conversion message is still greater than the second preset time period, the precharge is stopped.
9. The pre-charge control method according to claim 1, characterized in that, The pre-charge control method further includes: In response to receiving a pre-charge command, pre-charge control is initiated with the duty cycle of the pre-charge relay in the pre-charge circuit as the default duty cycle.
10. The pre-charge control method according to claim 1 or 9, characterized in that, The pre-charge control method further includes: In response to the second voltage difference between the main positive relay and the main negative relay of the pre-charge circuit not being greater than a preset voltage difference, the pre-charge control is stopped.
11. A pre-charge control device, applied to a pre-charge circuit, the pre-charge circuit being used to pre-charge a DC bus capacitor to increase the bus voltage of the DC bus, characterized in that, The pre-charge control device includes: A voltage determination module is used to determine the pre-charge target voltage corresponding to the DC bus in response to the bus voltage rise rate of the DC bus being lower than a preset rise rate during the pre-charging process. The duty cycle determination module is used to determine the optimal duty cycle of the precharge relay in the precharge circuit based on the precharge target voltage and the objective function; wherein, the objective function is constructed with the goal of minimizing the precharge duration and the equivalent impedance of the DC bus capacitor; A pre-charge control module is used to perform pre-charge control based on the optimal duty cycle.
12. A vehicle, characterized in that, The vehicle includes a power battery, and the power battery uses the pre-charge control device as described in claim 11 to control the pre-charge voltage.