Battery pack boost charging method, device, vehicle and storage medium

Abstract

The present application provides a boost charging method, device, vehicle and storage medium for a battery pack, which is applied to the vehicle field. The method includes: when there is a boost charging demand for the battery pack, obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage, determining the duty cycle target value according to the requested output voltage, the actual voltage and the charging port voltage, and outputting a corresponding drive signal to each phase bridge arm of the inverter circuit based on the duty cycle target value, thereby boost charging the battery pack. This method can adjust the control logic of the motor controller, that is, dynamically adjust the PWM duty cycle, so that the voltage control loop of the charging pile is in a saturated state, thereby ensuring that all charging piles can perform boost charging in the constant current output mode, thereby improving the charging efficiency and stability.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically, to a boost charging method, device, vehicle and storage medium for a battery pack in the field of vehicles. Background Art

[0002] With the rapid development of the electric vehicle market, more and more models are beginning to be equipped with 800V platform battery packs. These high-voltage platform vehicles can be quickly charged on high-voltage 750V or even 1000V charging piles. However, there are still some low-voltage 500V charging piles on the market, which cannot directly meet the charging needs of high-voltage platform vehicles.

[0003] In the related technology, the battery management unit of most manufacturers requests the charging pile to operate in a constant voltage output mode. The motor controller adjusts the duty cycle of the power device according to the output current requested by the battery management unit to achieve the purpose of making the collected current and the requested output current the same, thereby achieving the required charging current.

[0004] However, in early low-voltage charging piles, the constant voltage output mode is not supported, which causes the charging pile to fail to work properly when the battery management unit requests constant voltage output, thus affecting the user's charging experience, which urgently needs to be solved. Summary of the invention

[0005] The present application provides a boost charging method, device, vehicle and storage medium for a battery pack. The method can adjust the control logic of the motor controller, that is, dynamically adjust the PWM (Pulse Width Modulation) duty cycle, so that the voltage control loop of the charging pile is in a saturated state, thereby ensuring that all charging piles can perform boost charging in a constant current output mode, thereby improving the charging efficiency and stability.

[0006] In a first aspect, a boost charging method for a battery pack is provided, wherein the battery pack is connected in parallel with an inverter circuit, the method comprising: determining whether there is a boost charging demand for the battery pack; if there is the boost charging demand, obtaining a requested output voltage sent by a battery management unit to a charging pile, an actual voltage of the battery pack, and a charging port voltage; determining a duty cycle target value according to the requested output voltage, the actual voltage, and the charging port voltage, and outputting a corresponding drive signal to each phase bridge arm of the inverter circuit based on the duty cycle target value to boost charge the battery pack.

[0007] Through the above technical solution, the control logic of the motor controller can be adjusted, that is, the PWM duty cycle is dynamically adjusted, so that the voltage control loop of the charging pile is in a saturated state, thereby ensuring that all charging piles can perform boost charging in constant current output mode, thereby improving charging efficiency and stability.

[0008] In combination with the first aspect, in some possible implementations, determining the duty cycle target value based on the requested output voltage, the actual voltage and the charging port voltage includes: obtaining a duty cycle reference value based on the requested output voltage and the actual voltage, and determining a duty cycle compensation value based on the requested output voltage and the charging port voltage; obtaining the duty cycle target value based on the duty cycle reference value and the duty cycle compensation value.

[0009] Through the above technical scheme, the actual voltage of the battery pack and the output voltage of the charging pile are comprehensively considered through the duty cycle reference value, the duty cycle compensation value and the final superposition of the duty cycle target value, ensuring that the inverter circuit can dynamically adjust the output voltage according to the needs of the battery pack while compensating for the voltage drop caused by factors such as cable loss.

[0010] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, determining the duty cycle compensation value based on the requested output voltage and the charging port voltage includes: judging whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage; if the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, then using the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle, and re-executing the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage, until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0011] Through the above technical solution, when the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, the preset duty cycle can be reduced, so that the voltage and current control can be dynamically adjusted, thereby flexibly responding to changes in the battery pack and ensuring the safety and efficiency of the charging process.

[0012] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, after determining whether the difference between the requested output voltage and the charging port voltage is equal to the preset voltage, it also includes: if the difference between the requested output voltage and the charging port voltage is less than the preset voltage, then the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle is used as the duty cycle of the next control cycle, and the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage is re-executed until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0013] Through the above technical solution, when the difference between the requested output voltage and the charging port voltage is less than the preset voltage, the preset duty cycle can be increased, so that the voltage and current control can be dynamically adjusted, thereby flexibly responding to changes in the battery pack and ensuring the safety and efficiency of the charging process.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, obtaining the duty cycle reference value based on the requested output voltage and the actual voltage includes: calculating a first difference between the requested output voltage and the preset voltage; calculating a ratio of the first difference to the actual voltage, and obtaining the duty cycle reference value based on a preset threshold and the ratio.

[0015] Through the above technical solution, it is possible to ensure that the inverter circuit can dynamically adjust the output voltage according to the needs of the battery pack based on the calculation of the duty cycle reference value, so that the voltage of the battery pack gradually approaches the requested output voltage of the battery management unit.

[0016] In a second aspect, a boost charging device for a battery pack is provided, wherein the battery pack is connected in parallel with an inverter circuit, and the device comprises:

[0017] A judgment module, used to judge whether the battery pack has a boost charging requirement;

[0018] An acquisition module, used for acquiring the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage if the boost charging demand exists;

[0019] A charging module is used to determine a duty cycle target value according to the requested output voltage, the actual voltage and the charging port voltage, and output a corresponding drive signal to each phase arm of the inverter circuit based on the duty cycle target value to boost charging of the battery pack.

[0020] In conjunction with the second aspect, in some possible implementations, the charging module includes:

[0021] a determining unit, configured to obtain a duty cycle reference value according to the requested output voltage and the actual voltage, and determine a duty cycle compensation value according to the requested output voltage and the charging port voltage;

[0022] An acquisition unit is used to obtain the duty cycle target value according to the duty cycle reference value and the duty cycle compensation value.

[0023] In combination with the second aspect and the foregoing implementation manner, in some possible implementation manners, the determining unit includes:

[0024] A judging subunit, used to judge whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage;

[0025] A loop subunit, for using the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle if the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, and re-executing the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage, until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0026] In combination with the second aspect and the above implementation manner, in some possible implementation manners, after determining whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage, the determination subunit further includes:

[0027] A loop sub-component, which is used to use the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle if the difference between the requested output voltage and the charging port voltage is less than the preset voltage, and re-execute the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage, until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0028] In combination with the second aspect and the foregoing implementation manner, in some possible implementation manners, the determining unit includes:

[0029] A first calculation subunit, configured to calculate a first difference between the requested output voltage and the preset voltage;

[0030] The second calculation subunit is used to calculate the ratio of the first difference to the actual voltage, and obtain the duty cycle reference value according to a preset threshold and the ratio.

[0031] In a third aspect, a vehicle is provided, comprising the boost charging method for the battery pack described in the above embodiment.

[0032] In a fourth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first aspect or any possible implementation of the first aspect.

[0033] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the method in the above-mentioned first aspect or any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1A schematic diagram of a boost charging method for a battery pack in the related art;

[0035] Figure 2 A flowchart of a boost charging method for a battery pack provided in an embodiment of the present application;

[0036] Figure 3 A schematic diagram of the topology of a neutral point boost system according to an embodiment of the present application;

[0037] Figure 4 A topological diagram of a charging pile control algorithm according to an embodiment of the present application;

[0038] Figure 5 This is an overall flow chart of charging pile control according to an embodiment of the present application;

[0039] Figure 6 An example block diagram of a boost charging device for a battery pack provided in an embodiment of the present application;

[0040] Figure 7 A schematic diagram of the structure of a vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0042] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0043] With the rapid development of the electric vehicle market, more and more models are equipped with 800V platform battery packs. These high-voltage platform vehicles can be quickly charged on high-voltage 750V or even 1000V charging piles. However, there are still some low-voltage 500V charging piles on the market. These charging piles cannot directly meet the charging needs of high-voltage platform vehicles, such as Figure 1As shown, during the boost charging process, the battery management unit, the motor controller and the charging pile interact with each other. During the interaction process, the battery management unit of most automobile manufacturers requests the charging pile to work in the constant voltage output mode, and the motor controller adjusts the duty cycle of the power device according to the output current requested by the battery management unit, thereby achieving the purpose of the collected current being the same as the requested output current. However, for the early charging pile, there is no constant voltage output mode in its working mode, which results in that when the battery management unit requests the early charging pile constant voltage output, the charging pile does not work and cannot be charged, which affects the customer experience and causes complaints. Therefore, based on the above-mentioned problems, in order to perform boost charging on the early low-voltage charging pile, the motor controller needs to take certain measures to make the charging pile work in the constant current mode. The embodiment of the present application provides a boost charging strategy that enables the charging pile to work in the constant current output mode, so as to solve the problem that the early low-voltage charging pile does not support the constant voltage output mode in the prior art. By adjusting the control logic of the motor controller, both the early charging pile and the emerging charging pile can realize the boost charging in the constant current output mode, and improve the charging efficiency and stability.

[0044] Figure 2 It is a schematic flow chart of a boost charging method for a battery pack provided in an embodiment of the present application.

[0045] For example, Figure 2 As shown, the battery pack is connected in parallel with the inverter circuit, and the method includes:

[0046] In step S201, it is determined whether the battery pack has a voltage boost charging requirement.

[0047] Specifically, in order to solve the problem that the early low-voltage charging pile in the related art does not support the constant voltage output mode, the embodiment of the present application adopts a neutral point boost topology structure, and its main circuit connection relationship is as follows: Figure 3As shown, two ends of a battery pack (i.e., HVBattery (High Voltage Battery)) are connected in parallel with a first capacitor (i.e., bus capacitor C2 of a motor controller) and two ends of a first phase bridge arm (i.e., D1) of an inverter circuit, the midpoints of the three-phase bridge arms of the inverter circuit are respectively connected to the three-phase windings of the motor, two ends of a third phase bridge arm (i.e., D3) of the inverter circuit are connected to two ends of a second capacitor (i.e., C1) at a charging port of the motor controller (i.e., a fast charging pile), one end of the second capacitor is connected to one end of the third phase bridge arm through a first switch (i.e., K1), and the other end of the second capacitor is connected to the other end of the third phase bridge arm through a second switch (i.e., K2), a third switch (i.e., K3) is provided between the positive electrode of the battery pack and one end of the first capacitor, a fourth switch (i.e., K4) is provided between the negative electrode of the battery pack and the other end of the first capacitor, and a fifth switch (i.e., K5) is provided between the neutral point of the motor and a connection node between the first switch and the second capacitor.

[0048] Furthermore, if Figure 3 As shown, this topology connects the motor controller, power devices (D1, D2, D3) and capacitor C2 through the closure of relays K2, K3, K4 and K5, so that when there is a boost charging demand for the battery pack, the motor controller can dynamically adjust the duty cycle of the PWM signal according to the current requested by the battery management unit, and raise the voltage at the C2 capacitor, thereby achieving boost charging of the battery pack. The switching state of the relay is controlled by the motor controller, which is usually closed when the system starts and disconnected after charging is completed to ensure the safety and reliability of the system.

[0049] In step S202, if there is a boost charging demand, the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage are obtained.

[0050] Specifically, Figure 4 As shown in the figure, this is the control topology diagram of the charging pile, which mainly includes the outer loop - voltage control loop and the inner loop - current control loop. The dual-loop control structure can ensure the stability of voltage and current during the charging process, and can dynamically adjust the output according to the request of the battery management unit.

[0051] Specifically, when the battery pack has a boost charging demand, in the outer loop-voltage control loop, based on the request of the battery management unit, the requested output voltage of the charging pile is adjusted to ensure that it meets the needs of the battery pack. First, the actual voltage of the battery pack (i.e., Vout) is obtained. The battery management unit will send an initial requested output voltage (i.e., Vbms) to the charging pile according to the current state of the battery pack (such as power, temperature, etc.) to indicate the voltage that the charging pile needs to output. In order to protect the safety of the charging pile and the battery pack, the charging pile is provided with a maximum allowable output voltage (i.e., Vmax). The maximum allowable output voltage Vmax is usually determined by the hardware design of the charging pile to prevent overvoltage damage to the equipment; secondly, in order to ensure the output voltage of the charging pile The voltage meets the needs of the battery pack and does not exceed the safety range of the charging pile. The initial requested output voltage Vbms is compared with the maximum allowable output voltage Vmax of the charging pile, and the smaller value of the two is taken as the command input (i.e., Vref) of the voltage control loop. The battery management unit sends the requested output voltage Vref to the charging pile. That is to say, when Vbms≤Vmax, Vbms=Vref, and when Vbms>Vmax, Vmax=Vref. The command input is the set output voltage of the charging pile, that is, the requested output voltage Vref that the charging pile can ultimately output. This ensures that the requested output voltage Vref of the charging pile meets the needs of the battery pack and does not exceed the safety range of the charging pile.

[0052] Furthermore, in the dual-loop control structure of the charging pile, voltage feedback is the key signal in the voltage control loop, which reflects the voltage actually output from the charging pile to the battery pack. Voltage feedback is usually collected through devices such as voltage sensors or voltage divider resistors, which are mainly installed at the vehicle charging interface (such as Figure 3 The voltage across C1 in the figure is used to measure the actual voltage transmitted from the charging pile to the battery pack, that is, the charging port voltage (i.e. Vfb). This provides the real-time output voltage information of the charging pile, which can help the system dynamically adjust the output voltage information to ensure the stability of the charging process.

[0053] Furthermore, the requested output voltage Vref and the charging port voltage Vfb are compared, the difference is calculated, and the difference is processed by a PI controller to output a current command, whose main function is to eliminate the voltage error through proportional and integral terms to ensure that the output voltage quickly and stably tracks the voltage command, and the current command is compared with the initial requested output current Ibms sent by the battery management unit to the charging pile, and the smaller value of the two is taken to obtain the command input (i.e., Iref) of the current control loop. That is to say, when the current command ≤Ibms, the current command = Iref, and when the current command >Ibms, Ibms = Iref. The command input sets the output current of the charging pile, that is, the requested output current Iref that the charging pile can ultimately output, thereby ensuring that the requested output current of the charging pile meets the needs of the battery pack and does not exceed the safety range of the charging pile.

[0054] Furthermore, in the dual-loop control structure of the charging pile, current feedback is a key signal in the current control loop, which is derived from the current sampling (i.e., Ifb) on the input side of the charging pile, reflecting the current actually output by the charging pile to the battery pack, and then further comparing the requested output current Iref with the actual current sampling Ifb, and calculating the difference. After being processed by the loop PI controller, the output controls the PWM duty cycle of the bridge arms D1, D2, and D3 to adjust the on-time of the power device, thereby adjusting the output current and ensuring that it tracks the current command. Since Iref is actually equal to the initial requested output current Ibms of the battery management unit, the current control loop will ensure that the requested output current Iref is always equal to the initial requested output current Ibms of the battery management unit. At this time, the charging pile operates in a constant current output mode, which can enable a charging pile without a constant voltage output mode to perform boost charging.

[0055] It should be noted that since the early low-voltage charging piles did not have a constant voltage working mode, in order to boost charging on the early low-voltage charging piles, the motor controller needs to take certain measures to make the charging pile work in a constant current mode, such as Figure 4 As shown, if the charging pile is to work in constant current output mode and make the charging pile output according to the requested current of the battery management unit, it is necessary to make the voltage control loop of the charging pile work in saturation mode, that is, make Vref greater than Vfb by a certain value, so that the current command output by the PI controller in the voltage control loop is infinite. When the current command is infinite, at this time, Iref is actually equal to the initial requested output current Ibms of the battery management unit, and the output of the voltage control loop will no longer affect the current control loop. At this time, the charging pile works in constant current output mode, that is, the charging pile without constant voltage output mode can be boosted and charged.

[0056] Since Vref is the requested output voltage of the battery management unit received by the charging pile, the motor controller software cannot process this signal. Since the C1 capacitor is inside the motor controller, based on the Boost circuit characteristics and the duty cycle calculation principle, the motor controller software uses relevant formulas for calculation. To facilitate the understanding of those skilled in the art, the duty cycle dynamic adjustment process in the dual control loop will be discussed in detail below.

[0057] In step S203, the duty cycle target value is determined according to the requested output voltage, the actual voltage and the charging port voltage, and a corresponding drive signal is output to each phase arm of the inverter circuit based on the duty cycle target value to boost and charge the battery pack.

[0058] Optionally, in one embodiment of the present application, the duty cycle target value is determined based on the requested output voltage, the actual voltage and the charging port voltage, including: obtaining a duty cycle reference value based on the requested output voltage and the actual voltage, and determining a duty cycle compensation value based on the requested output voltage and the charging port voltage; obtaining the duty cycle target value based on the duty cycle reference value and the duty cycle compensation value.

[0059] Optionally, in one embodiment of the present application, a duty cycle reference value is obtained based on the requested output voltage and the actual voltage, including: calculating a first difference between the requested output voltage and a preset voltage; calculating a ratio of the first difference to the actual voltage, and obtaining the duty cycle reference value based on a preset threshold and the ratio.

[0060] Among them, the preset voltage, preset threshold and preset duty cycle can be set by technical personnel in this field according to actual test requirements, or can be obtained through a limited number of computer simulations, and are not specifically limited here.

[0061] Specifically, when the requested output voltage Vref, the actual voltage Vout of the battery pack and the charging port voltage Vfb sent by the battery management unit to the charging pile are obtained, it is necessary to further determine the duty cycle target value based on the requested output voltage Vref, the actual voltage Vout of the battery pack and the charging port voltage Vfb, so as to output the corresponding drive signal to each phase arm of the inverter circuit through dynamic adjustment of the duty cycle target value, so as to boost and charge the battery pack.

[0062] Specifically, if Figure 4 and Figure 5As shown, first, the requested output voltage Vref and the actual voltage Vout of the battery pack are sent to the duty cycle calculation unit, and the difference between the requested output voltage Vref and the preset voltage (for example, △V) is further calculated to obtain a first difference between the requested output voltage Vref and the preset voltage; secondly, the calculated first difference is compared with the actual voltage Vout of the battery pack to obtain a ratio of the first difference to the actual voltage Vout of the battery pack; finally, a duty cycle reference value is obtained according to a preset threshold value (for example, 1) and the ratio, so that the output voltage can be dynamically adjusted based on the duty cycle reference value, and the formula can be expressed as:

[0063]

[0064] Optionally, in one embodiment of the present application, the duty cycle compensation value is determined based on the requested output voltage and the charging port voltage, including: judging whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage; if the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, then using the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle, and re-executing the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack, and the charging port voltage, until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0065] Specifically, after calculating the duty cycle reference value, the embodiment of the present application can determine the duty cycle compensation value based on the requested output voltage Vref and the charging port voltage Vfb. The duty cycle compensation value is an additional duty cycle adjustment amount calculated based on the charging port voltage Vfb and the requested output voltage Vref. Its purpose is to compensate for the voltage drop caused by cable loss, connector resistance and other factors to ensure that the output voltage of the charging pile always tracks the requested output voltage Vref of the battery management unit.

[0066] Specifically, first, calculate whether the difference between the requested output voltage Vref and the charging port voltage Vfb on both sides of C1 is equal to the preset voltage △V (for example, 20V) to determine whether the difference between Vref and Vfb is within an acceptable range, that is, whether duty cycle compensation is required; secondly, if the difference between the requested output voltage Vref and the charging port voltage Vfb is greater than the preset voltage, that is, Vref-Vfb>△V, then it means that the charging port voltage Vfb is lower than the requested output voltage Vref, and the output voltage of the charging pile is insufficient, so the output voltage needs to be increased. In order to increase the output voltage, the system will additionally reduce the preset duty cycle δ of the inverter circuit in each control cycle. The preset duty cycle δ is the duty cycle compensation value, so as to reduce the preset duty cycle. δ dynamically adjusts the output voltage, so that the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle δ can be used as the duty cycle of the next control cycle, and the steps of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage are re-executed. At this time, Vref-Vfb gradually decreases and approaches △V until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage. By gradually reducing the preset duty cycle δ, the conduction time of the inverter circuit is shortened, thereby gradually increasing the output voltage to ensure that the new charging port voltage Vfb gradually approaches the new requested output voltage Vref, and finally makes the new Vref-new Vfb=△V, thereby achieving precise control of the output voltage.

[0067] Optionally, in one embodiment of the present application, after determining whether the difference between the requested output voltage and the charging port voltage is equal to the preset voltage, it also includes: if the difference between the requested output voltage and the charging port voltage is less than the preset voltage, then the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle is used as the duty cycle of the next control cycle, and the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage is re-executed until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0068] Specifically, if the difference between the requested output voltage Vref and the charging port voltage Vfb is less than the preset voltage, that is, Vref-Vfb<△V, it means that the charging port voltage Vfb is higher than the requested output voltage Vref, and the output voltage of the charging pile is too high, so the output voltage needs to be reduced. In order to reduce the output voltage, the system will increase the preset duty cycle δ of the inverter circuit in each control cycle to dynamically adjust the output voltage by increasing the preset duty cycle δ, so that the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle δ can be used as the duty cycle of the next control cycle, and the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage is re-executed. At this time, Vref-Vfb gradually increases and approaches △V until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage. By gradually increasing the duty cycle δ, the system can gradually reduce the output voltage to ensure that the new charging port voltage Vfb gradually approaches the new requested output voltage Vref, and finally make the new Vref-new Vfb=△V, thereby achieving precise control of the output voltage.

[0069] Furthermore, if the difference between the requested output voltage Vref and the charging port voltage Vfb is equal to the preset voltage, that is, Vref-Vfb=△V, it means that the charging port voltage Vfb is close to the requested output voltage Vref, and the system does not need to further dynamically adjust the duty cycle. It will continue to monitor the changes of the requested output voltage Vref and the charging port voltage Vfb based on the duty cycle of the current cycle, and perform dynamic adjustment again when a new voltage difference appears between the requested output voltage Vref and the charging port voltage Vfb in the subsequent period, so as to ensure the stability of the charging process.

[0070] Therefore, based on the duty cycle reference value and duty cycle compensation value calculated above, the duty cycle reference value and the duty cycle compensation value are superimposed to obtain the duty cycle target value, which comprehensively considers the actual voltage of the battery pack and the output voltage of the charging pile to ensure that the inverter circuit can dynamically adjust the output voltage according to the needs of the battery pack, and then sends the duty cycle target value to the underlying drive module, which converts the duty cycle target value into a PWM signal and outputs a corresponding drive signal to each phase arm of the inverter circuit, that is, outputs the PWM signal to D1, D2, and D3 respectively, thereby controlling the output voltage and current of the inverter circuit to ensure that it always tracks the requested output voltage of the battery management unit, thereby protecting the safety of the battery and the charging pile and improving the charging efficiency.

[0071] Through the above control strategy, the charging pile can operate in constant current mode to output a stable current. Even if the output voltage of the charging pile is low, due to the precise adjustment of the current control loop, the battery pack can still obtain the required charging current. As the battery voltage gradually increases, the output voltage of the charging pile will also increase accordingly, thereby achieving boost charging.

[0072] Therefore, based on the specific discussion of the above embodiments, the following beneficial effects can be achieved:

[0073] (1) Improves the compatibility of early charging piles and emerging charging piles by allowing the voltage control loop to enter a saturated state, forcing the charging pile to output a constant current according to the current requested by the battery management unit, so that all charging piles can operate in a constant current output mode for boost charging;

[0074] (2) Ensure safety and stability during the charging process. In constant current mode, the current output by the charging pile is always kept within the range requested by the battery management unit, avoiding overcurrent or undercurrent. At the same time, by allowing the voltage control loop to enter a saturated state, the system no longer attempts to adjust the output voltage, but instead focuses on maintaining a constant output current, thereby reducing the risk of voltage fluctuations and ensuring the stability of the charging process.

[0075] (3) Optimize battery charging efficiency. Through precise adjustment of the current control loop, the system can dynamically adjust the output current according to the status of the battery pack (such as power, temperature, etc.), reduce current ripple, reduce motor heating, and ensure that the charging current in each stage is in the optimal state. The charging rate is significantly improved compared to before, reducing the charging time.

[0076] In summary, according to the boost charging method of the battery pack of the embodiment of the present application, when there is a boost charging demand for the battery pack, the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage are obtained, and the duty cycle target value is determined according to the requested output voltage, the actual voltage and the charging port voltage, so as to output a corresponding drive signal to each phase bridge arm of the inverter circuit based on the duty cycle target value, thereby boost charging the battery pack. This method can adjust the control logic of the motor controller, that is, dynamically adjust the PWM duty cycle, so that the voltage control loop of the charging pile is in a saturated state, thereby ensuring that all charging piles can perform boost charging in the constant current output mode, thereby improving the charging efficiency and stability.

[0077] Figure 6 It is a structural schematic diagram of a boost charging device for a battery pack provided in an embodiment of the present application.

[0078] For example, Figure 6 As shown, the battery pack is connected in parallel with the inverter circuit, and the device may include: a judgment module 100, an acquisition module 200 and a charging module 300.

[0079] The determination module 100 is used to determine whether the battery pack has a boost charging requirement;

[0080] The acquisition module 200 is used to obtain the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage if there is a boost charging demand;

[0081] The charging module 300 is used to determine the duty cycle target value according to the requested output voltage, the actual voltage and the charging port voltage, and output a corresponding drive signal to each phase bridge arm of the inverter circuit based on the duty cycle target value to boost and charge the battery pack.

[0082] Optionally, in one embodiment of the present application, the charging module 300 includes:

[0083] A determination unit, configured to obtain a duty cycle reference value according to a requested output voltage and an actual voltage, and determine a duty cycle compensation value according to the requested output voltage and a charging port voltage;

[0084] The acquisition unit is used to obtain the duty cycle target value according to the duty cycle reference value and the duty cycle compensation value.

[0085] Optionally, in one embodiment of the present application, the determining unit includes:

[0086] A judging subunit, used to judge whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage;

[0087] A loop sub-unit is used to use the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle if the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, and re-execute the steps of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0088] Optionally, in one embodiment of the present application, after determining whether the difference between the requested output voltage and the charging port voltage is equal to the preset voltage, the determination subunit further includes:

[0089] A loop sub-component is used to use the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle if the difference between the requested output voltage and the charging port voltage is less than the preset voltage, and re-execute the steps of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

[0090] Optionally, in one embodiment of the present application, the determining unit includes:

[0091] A first calculation subunit, configured to calculate a first difference between a requested output voltage and a preset voltage;

[0092] The second calculation subunit is used to calculate the ratio of the first difference to the actual voltage, and obtain a duty cycle reference value according to a preset threshold and the ratio.

[0093] In summary, according to the boost charging device of the battery pack of the embodiment of the present application, when there is a boost charging demand for the battery pack, the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage are obtained, and the duty cycle target value is determined according to the requested output voltage, the actual voltage and the charging port voltage, so as to output a corresponding drive signal to each phase bridge arm of the inverter circuit based on the duty cycle target value, thereby boost charging the battery pack. This method can adjust the control logic of the motor controller, that is, dynamically adjust the PWM duty cycle, so that the voltage control loop of the charging pile is in a saturated state, thereby ensuring that all charging piles can perform boost charging in the constant current output mode, thereby improving the charging efficiency and stability.

[0094] Figure 7 A schematic structural diagram of a vehicle provided in an embodiment of the present application.

[0095] It should be understood that the above-described method can be applied to Figure 7 In a vehicle of the structure shown.

[0096] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute the boost charging method for the battery pack provided in the embodiment of the present application.

[0097] Furthermore, the device also includes: a communication interface 703 for communication between the memory 701 and the processor 702 .

[0098] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0099] It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0100] It should be understood that the device provided in this embodiment is used to execute the above-mentioned boost charging method for a battery pack, and thus can achieve the same effect as the above-mentioned implementation method.

[0101] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to a vehicle, the processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing mutual program codes, etc.

[0102] The processing module may be a processor 702 or a controller, which may implement or execute various exemplary logic blocks, modules and circuits disclosed in the present application. The processor 702 may also be a combination that implements a computing function, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory 701.

[0103] In addition, the device provided in the embodiments of the present application may specifically be a chip, a component or a module, and the chip may include a connected processor 702 and a memory 701; wherein the memory 701 is used to store instructions, and when the processor calls and executes the instructions, the chip can execute the boost charging method for the battery pack provided in the above embodiments.

[0104] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a battery pack boost charging method provided in the above embodiment.

[0105] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a boost charging method for a battery pack provided in the above-mentioned embodiment.

[0106] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0107] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned 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.

[0108] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0109] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A boost charging method for a battery pack, characterized in that: The battery pack is connected in parallel with the inverter circuit, wherein the method comprises the following steps: Determine whether the battery pack has a boost charging requirement; If the boost charging requirement exists, the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage are obtained; A duty cycle target value is determined according to the requested output voltage, the actual voltage and the charging port voltage, and a corresponding drive signal is output to each phase arm of the inverter circuit based on the duty cycle target value to boost and charge the battery pack.

2. The method according to claim 1, characterized in that The step of determining a duty cycle target value according to the requested output voltage, the actual voltage, and the charging port voltage includes: Obtaining a duty cycle reference value according to the requested output voltage and the actual voltage, and determining a duty cycle compensation value according to the requested output voltage and the charging port voltage; The duty ratio target value is obtained according to the duty ratio reference value and the duty ratio compensation value.

3. The method according to claim 2, characterized in that The determining the duty cycle compensation value according to the requested output voltage and the charging port voltage includes: Determining whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage; If the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle is used as the duty cycle of the next control cycle, and the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage is re-executed until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

4. The method according to claim 3, characterized in that After determining whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage, the method further includes: If the difference between the requested output voltage and the charging port voltage is less than the preset voltage, the sum of the duty cycle of the current control cycle of the motor controller and the preset duty cycle is used as the duty cycle of the next control cycle, and the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage is re-executed until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

5. The method according to claim 3, characterized in that: The obtaining a duty cycle reference value according to the requested output voltage and the actual voltage comprises: Calculating a first difference between the requested output voltage and the preset voltage; The ratio of the first difference to the actual voltage is calculated, and the duty cycle reference value is obtained according to a preset threshold and the ratio.

6. A boost charging device for a battery pack, characterized in that: The battery pack is connected in parallel with the inverter circuit, which includes: A judgment module, used to judge whether the battery pack has a boost charging requirement; An acquisition module, used for acquiring the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage if the boost charging demand exists; A charging module is used to determine a duty cycle target value according to the requested output voltage, the actual voltage and the charging port voltage, and output a corresponding drive signal to each phase arm of the inverter circuit based on the duty cycle target value to boost charging of the battery pack.

7. The device according to claim 6, characterized in that The charging module comprises: a determining unit, configured to obtain a duty cycle reference value according to the requested output voltage and the actual voltage, and determine a duty cycle compensation value according to the requested output voltage and the charging port voltage; An acquisition unit is used to obtain the duty cycle target value according to the duty cycle reference value and the duty cycle compensation value.

8. The device according to claim 7, characterized in that The determining unit comprises: A judging subunit, used to judge whether the difference between the requested output voltage and the charging port voltage is equal to a preset voltage; A loop subunit, for using the difference between the duty cycle of the current control cycle of the motor controller and the preset duty cycle as the duty cycle of the next control cycle if the difference between the requested output voltage and the charging port voltage is greater than the preset voltage, and re-executing the step of obtaining the requested output voltage sent by the battery management unit to the charging pile, the actual voltage of the battery pack and the charging port voltage, until the difference between the new requested output voltage and the new charging port voltage is equal to the preset voltage.

9. A vehicle, characterized in that: The vehicle comprises: a boost charging method for a battery pack as described in any one of claims 1 to 5 above.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 5 is implemented.

Images