Battery management system, battery system and electric device

Abstract

The invention discloses a battery management system, a battery system and an electric device. The battery management system comprises a current acquisition circuit, a control circuit, a driving circuit and a voltage conversion circuit. The current sampling resistor is arranged on the main circuit; the control circuit is connected to the current sampling resistor; the driving circuit is connected to the control circuit and the current sampling resistor; the voltage conversion circuit is connected to the driving circuit and is arranged on the main circuit; the control circuit is configured to collect actual current flowing through the current sampling resistor, read a target current value corresponding to the battery information based on the battery information, and generate a current adjusting signal based on the current value of the actual current and the target current value; and the driving circuit is configured to collect the actual current flowing through the current sampling resistor and generate a driving signal based on the actual current and the current adjusting signal so as to drive the voltage conversion circuit, so that the current value of the actual current approaches the target current value. According to the embodiment of the invention, the control precision of the voltage conversion circuit can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power supply, and particularly relates to a battery management system, a battery system and a power utilization device. BACKGROUND

[0002] With the development and popularization of new energy technology, recycling and reuse of batteries have become inevitable, whether for environmental protection or economic value considerations.

[0003] In some reuse scenarios, such as in an electric tricycle system, the input voltage of the vehicle controller is relatively high, which makes the step battery utilization system possibly subject to battery module voltage limitation, so that step battery modules with low string number are difficult to be directly configured for occasions requiring high voltage. Therefore, by introducing a one-stage bidirectional DCDC voltage conversion circuit for step-up / down control, compatibility of different battery string numbers to the system can be achieved.

[0004] However, the related art has the problem of low control accuracy when controlling the voltage conversion circuit. SUMMARY

[0005] The application embodiments provide a battery management system, a battery system and a power utilization device, which can improve the control accuracy of the voltage conversion circuit.

[0006] In a first aspect, the application embodiments provide a battery management system, comprising: a current sampling resistor arranged on a main circuit; a control circuit connected to the current sampling resistor; a drive circuit connected to the control circuit and the current sampling resistor; a voltage conversion circuit connected to the drive circuit, the voltage conversion circuit being arranged on the main circuit; the control circuit is configured to: collect an actual current flowing through the current sampling resistor, read a target current value corresponding to battery information based on the battery information, and generate a current adjustment signal based on the current value of the actual current and the target current value; the drive circuit is configured to: collect the actual current flowing through the current sampling resistor, generate a drive signal based on the actual current and the current adjustment signal, and use the drive signal to drive the voltage conversion circuit so that the current value of the actual current approximates the target current value; wherein the battery information includes battery temperature and battery voltage, or the battery information includes battery temperature and battery SOC.

[0007] In a first aspect, in a possible embodiment, the current sampling resistor comprises a first current sampling resistor and a second current sampling resistor; The first current sampling resistor is connected to the control circuit, and the second current sampling resistor is connected to the driving circuit. The control circuit is specifically configured to: read, based on the battery information, a target current value from a preset mapping function, calculate a duty cycle compensation amount based on a difference between the actual current value and the target current value; generate a current adjustment signal based on the duty cycle compensation amount and an initial duty cycle, wherein the initial duty cycle represents a duty cycle corresponding to the target current value.

[0008] In a possible implementation of the first aspect, The driving circuit is specifically configured to: generate, through closed-loop control of the driving circuit, a driving signal based on a difference between a voltage value represented by the voltage signal and a voltage value represented by the current adjustment signal.

[0009] In a possible implementation of the first aspect, The control circuit comprises an analog front-end circuit and a micro control unit, the analog front-end circuit is connected to the battery and the current sampling resistor, and the micro control unit is connected to the analog front-end circuit. The battery management system comprises a filter circuit, and the filter circuit is connected to the micro control unit and the driving circuit. The micro control unit is configured to: obtain a target current value, calculate a duty cycle compensation amount based on a difference between an actual current value and the target current value, adjust an initial duty cycle based on the duty cycle compensation amount to obtain a target duty cycle, and generate an electrical signal with the target duty cycle; The filter circuit is configured to: filter the electrical signal with the target duty cycle to obtain a current adjustment signal; The initial duty cycle represents a duty cycle corresponding to the target current value.

[0010] In a possible implementation of the first aspect, The micro control unit is specifically configured to: multiply the duty cycle compensation amount by a preset influence factor to obtain a target compensation amount, and add the target compensation amount to the initial duty cycle to obtain the target duty cycle.

[0011] In a possible implementation of the first aspect, The micro control unit is specifically configured to: in response to the target duty cycle being less than or equal to a preset duty cycle threshold, generate the electrical signal with the target duty cycle; and in response to the target duty cycle being greater than the duty cycle threshold, generate the electrical signal with the duty cycle threshold.

[0012] In a possible implementation of the first aspect, the filter circuit comprises: A first filter sub-circuit connected to the micro control unit. a second filter sub-circuit connected to the first filter sub-circuit; a diode, an anode of the diode connected to the second filter sub-circuit, and a cathode of the diode connected to the driving circuit.

[0013] In a possible implementation of the first aspect, the voltage conversion circuit includes N voltage conversion sub-circuits, N being an integer greater than or equal to 1; The N voltage conversion sub-circuits are connected in parallel, and the voltage conversion sub-circuits are connected to the driving circuit.

[0014] In a possible implementation of the first aspect, A phase difference between the N driving signals output by the driving circuit is 2Π / N.

[0015] Based on the same inventive concept, in a second aspect, the embodiments of the present application further provide a battery system including a battery module and the battery management system according to any of the embodiments of the first aspect.

[0016] Based on the same inventive concept, in a third aspect, the embodiments of the present application further provide a power consumption device including the battery system according to the embodiments of the second aspect.

[0017] The battery management system, the battery system and the power utilization device provided by the embodiments of the present application comprise a current collection circuit, a control circuit, a driving circuit and a voltage conversion circuit. The current sampling resistor is arranged on the main circuit, and the actual current of the main circuit can be obtained by collecting the actual current flowing through the current sampling resistor. The control circuit is connected to the current sampling resistor. The driving circuit is connected to the control circuit and the current sampling resistor. The voltage conversion circuit is connected to the driving circuit, and the voltage conversion circuit is arranged on the main circuit. The control circuit is configured to collect the actual current flowing through the current sampling resistor, read the target current value corresponding to the battery information based on the battery information, and generate the electric signal corresponding to the target current value (the electric signal can be referred to as the current adjustment signal) based on the difference between the current value of the actual current and the target current value, that is, the target current value is converted into the corresponding electric signal (such as a voltage signal). Subsequently, the driving circuit can compare the current adjustment signal with the actual current. If the current adjustment signal is a voltage signal, the current adjustment signal is compared with the voltage signal corresponding to the actual current. The driving circuit is configured to collect the actual current flowing through the current sampling resistor and generate the driving signal based on the actual current and the current adjustment signal, that is, the driving signal is obtained by the driving circuit based on the feedback actual current for hardware closed-loop control. The driving signal is used to drive the voltage conversion circuit to adjust the actual current in the battery charging and discharging loop, so that the current value of the actual current approaches the target current value. Therefore, by combining software control (the actual current is fed back to the control circuit, and the control circuit adjusts the current adjustment signal corresponding to the target current value based on the feedback actual current for closed-loop control) and hardware control (the actual current is fed back to the driving circuit, and the driving circuit adjusts the driving signal of the switching tube based on the feedback actual current for closed-loop control), the control accuracy of the voltage conversion circuit is improved, the current value of the actual current on the main circuit approaches the target current value, and the fine control of the charging and discharging power is realized without increasing additional cost. BRIEF DESCRIPTION OF DRAWINGS

[0018] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments thereof as taken in conjunction with the accompanying drawings, in which like references denote like features, and in which:

[0019] Figure 1 is a circuit principle diagram for generating a current adjustment signal in the battery management system provided by the embodiments of the present application; Figure 2 is a structural schematic diagram of the battery management system provided by the embodiments of the present application; Figure 3 is a structural schematic diagram of the battery management system provided by the embodiments of the present application; Figure 4is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 5 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 6 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 7 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 8 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 9 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 10 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 11 is another structural schematic diagram of a battery management system provided by an embodiment of the present application; Figure 12 is another structural schematic diagram of a battery management system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. To make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are configured only to explain the present application, and are not configured to limit the present application. The present application can be implemented without some of the specific details by those skilled in the art. The following description of the embodiments is merely to provide a better understanding of the present application by showing examples of the present application.

[0021] It should be noted that, in this document, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0022] It should be understood that the term "and / or" used herein is only to describe an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which can represent three cases of existence of A alone, existence of A and B at the same time, and existence of B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0023] Various modifications and changes can be made to the present application in light of the foregoing description, without departing from the spirit or scope thereof. Accordingly, the present application is intended to embrace all such modifications and changes as fall within the scope of the corresponding claims (technical solutions claimed to be protected), and their equivalents. It should be noted that the embodiments provided by the present application can be combined with each other without contradiction, if possible.

[0024] Before describing the technical solutions provided by the embodiments of the present application, in order to facilitate the understanding of the embodiments of the present application, the present application first specifically describes the problems existing in the related art: With the development and popularization of new energy technology, whether for environmental protection or economic value considerations, recycling of batteries has become inevitable.

[0025] In some recycling scenarios, such as in an electric tricycle system, the input voltage of the vehicle controller is relatively high, which makes the step battery utilization system may be limited by the voltage of the battery module, making it difficult for low-string step battery modules to be directly configured to occasions that require higher voltage.

[0026] By introducing a one-stage bidirectional DCDC voltage conversion circuit (including a BOOST boost circuit and a BUCK buck circuit) in series in the main circuit (the charge and discharge circuit of the battery module) for boost and buck control, the compatibility of different battery string numbers to the system can be achieved. For example, when the voltage of the low-string step battery module is low, the BOOST circuit can be used to boost the voltage to power the load (such as the vehicle controller). For example, when the voltage of the power supply is relatively high, the BUCK circuit can be used to step down the voltage to charge the battery module.

[0027] However, the related art has the problem of low control precision when controlling the voltage conversion circuit to boost and buck.

[0028] For example, some related technologies employ pure software control. Pure software control refers to implementing control logic using software algorithms within a microcontroller unit (MCU), without relying on hardware control circuits or dedicated hardware control chips. Software control offers high flexibility (e.g., PID parameters or control strategies can be adjusted through software upgrades), but it suffers from significant technical bottlenecks: limited by the ADC sampling period, software calculation delay, and loop bandwidth, its dynamic response and accuracy are insufficient, resulting in weak tracking ability of input signals, low real-time performance, and an inability to promptly correct control deviations. Furthermore, delay and accuracy issues can easily lead to system instability, failing to meet the demands for high dynamics and high precision control.

[0029] In view of this, in order to improve development efficiency and meet the requirements of high dynamic and high precision control, some related technologies use dedicated hardware control chips (such as dedicated DC-DC control chips: LM5171) to implement control logic.

[0030] For example, such as Figure 1 As shown, the microcontroller unit (MCU) can read the target current value (e.g., 4.5A) on the main circuit from the preset mapping function by collecting battery information such as the real-time temperature of the battery. Then, the MCU calculates the duty cycle D (e.g., 0.5) corresponding to the target current value (e.g., 4.5A) on the main circuit through a software algorithm, and generates a two-level electrical signal with this duty cycle. After passing through a second-order RC filter circuit, it generates the corresponding analog voltage signal ISETx.

[0031] The hardware control chip LM5171 needs to refer to the ISETx voltage value to generate the drive signal. The more accurate the ISETx voltage value, the more accurate the drive signal of the switching transistor generated by the hardware control chip LM5171 will be.

[0032] The drive signal generated by the hardware control chip LM5171 drives the switching transistors in the DC-DC voltage conversion circuit to turn on or off at appropriate times, thereby controlling the actual current in the main circuit to make the actual current close to the target current value. The more accurate the ISETx voltage value, the more accurate the drive signal generated by the hardware control chip LM5171, and the closer the actual current is to the target current value.

[0033] However, the device parameters of the dedicated hardware control chip LM5171 are affected by temperature, which can cause deviations and thus affect its control accuracy. Furthermore, the accuracy of the ISETx voltage value transmitted from the microcontroller unit (MCU) to the LM5171 hardware control chip via the RC filter circuit is affected by the following four factors: 1) The voltage accuracy of the power supply voltage Vpwmh of the microcontroller unit (MCU). For example, if the power supply voltage Vpwmh of the MCU is 3.3V, then the 3.3V voltage accuracy will affect the ISETx voltage value.

[0034] 2) the filtering accuracy of the second-order RC filter network.

[0035] 3) the turn-on voltage drop accuracy of the front-end diode VD of the ISETx voltage (the turn-on voltage drop of the diode VD is affected by temperature, current, or device consistency).

[0036] 4) the voltage difference caused by the line impedance Rgnd (for example, Rgnd = 0.64 x 10^-3 Ω) between the GND of the micro control unit MCU and the GND of the hardware control chip LM5171, so that the potential (for example, 0 V) of the GND of the dedicated hardware control chip LM5171 is different from the potential (for example, 4 x Rgnd x I_dc) of the reference ground GND of the micro control unit MCU. Therefore, the potential of the high level of the two-level electrical signal with a duty ratio output by the micro control unit MCU is Vpwmh + 4 x Rgnd x I_dc, and there is an error between Vpwmh, which affects the ISETx voltage value.

[0037] The above four reasons are related to the devices themselves and temperature rise, and have no regular characteristics, and cannot be eliminated by simply modifying the hardware circuit or compensation. The driving signal of the switch generated by the dedicated hardware control chip LM5171 has an error, and the switch in the DCDC voltage conversion circuit cannot be accurately controlled to turn on or turn off at the right time, so that the actual current on the main circuit (the charge and discharge circuit of the battery module) is inconsistent with the target current value, which affects the safety of battery charging and the reliability of the system.

[0038] It should be noted that the selection of the dedicated hardware control chip LM5171 and the second-order RC filter circuit in the above examples is only an example and does not limit the present application.

[0039] Therefore, the embodiments of the present application provide a battery management system, a battery system, and a power utilization device, which can improve the control accuracy of the voltage conversion circuit by combining software control (the actual current is fed back to the control circuit, and the control circuit adjusts the current adjustment signal corresponding to the target current value based on the feedback actual current) and hardware control (the actual current is fed back to the driving circuit, and the driving circuit adjusts the driving signal of the switch based on the feedback actual current), so that the current value of the actual current on the main circuit approaches the target current value, and the fine control of the charging and discharging power is realized without increasing additional costs.

[0040] The data update conflict monitoring method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0041] Figure 2 is a structural schematic diagram of a battery management system provided by the embodiments of the present application, asFigure 2 As shown in the figure, the battery management system 100 can include a current sampling resistor 10, a control circuit 20, a driving circuit 30 and a voltage conversion circuit 40.

[0042] The current sampling resistor 10 is arranged on the main circuit.

[0043] The main circuit is the charging and discharging circuit of the battery module. For example, as shown in the figure, the main circuit refers to the charging loop in which the charger 300 charges the battery module 200 through the voltage conversion circuit 40; as shown in the figure, the main circuit refers to the discharging loop in which the battery module 200 supplies power to the load 400 through the voltage conversion circuit 40. Figure 2 The main circuit refers to the charging loop in which the charger 300 charges the battery module 200 through the voltage conversion circuit 40; as shown in the figure, the main circuit refers to the discharging loop in which the battery module 200 supplies power to the load 400 through the voltage conversion circuit 40. Figure 3 The main circuit refers to the charging loop in which the charger 300 charges the battery module 200 through the voltage conversion circuit 40; as shown in the figure, the main circuit refers to the discharging loop in which the battery module 200 supplies power to the load 400 through the voltage conversion circuit 40.

[0044] The current sampling resistor 10 is arranged on the main circuit, so the actual current flowing through the current sampling resistor 10 is the actual current of the main circuit, and thus the actual current of the main circuit can be collected by arranging the current sampling resistor 10 on the main circuit.

[0045] It should be noted that the ultimate control target of the embodiment of the present application is to make the current value of the actual current of the main circuit approach the target current value, wherein the target current value is not a fixed value, but is determined by the actual state of the battery module in real time. For example, the target current value under the actual working condition can be read from a pre-set mapping function according to the actual temperature of each battery cell in the battery module and the actual voltage of the battery cell, or the target current value under the actual working condition can also be read from a pre-set mapping function according to the temperature of each battery cell in the battery module and the battery state of charge (SOC), wherein the battery state of charge SOC refers to the percentage of the remaining capacity of the battery to its total capacity, and the value range is 0-100%.

[0046] The control circuit 20 is connected to the current sampling resistor 10.

[0047] The driving circuit 30 is connected to the control circuit 20 and the current sampling resistor 10.

[0048] The voltage conversion circuit 40 is connected to the driving circuit 30, and the voltage conversion circuit 40 is arranged on the main circuit.

[0049] The control circuit 20 and the driving circuit 30 are both connected to the current sampling resistor 10, which means that the control circuit 20 can collect the actual current flowing through the current sampling resistor 10 for closed-loop control, and the driving circuit 30 can also collect the actual current flowing through the current sampling resistor 10 for closed-loop control. The control circuit 20 realizes closed-loop control through software algorithm, and the driving circuit 30 realizes closed-loop control through hardware circuit. Closed-loop control can be simply understood as adjusting the output by comparing the error between two input signals (one is the actual quantity and the other is the target quantity).

[0050] The control circuit 20 is configured to: collect an actual current flowing through the current sampling resistor 10 (for example, the actual current flowing through the current sampling resistor 10 can be obtained by dividing a voltage across the current sampling resistor 10 by a resistance value of the current sampling resistor 10), read a target current value corresponding to the battery information based on the battery information, and generate a current regulation signal ISETx based on the current value of the actual current and the target current value.

[0051] The battery information includes a battery temperature and a battery voltage, or the battery information includes a battery temperature and a battery state of charge SOC.

[0052] The target current value can be understood as a maximum charging / discharging current that can meet safety requirements under the current working condition.

[0053] Exemplarily, the target current value can be obtained by querying a preset mapping table according to a single cell temperature and a single cell voltage. For example, four combinations of the highest single cell voltage, the lowest single cell voltage, the highest single cell temperature, and the lowest single cell temperature (the highest single cell voltage and the highest single cell temperature, the highest single cell voltage and the lowest single cell temperature, the lowest single cell voltage and the highest single cell temperature, and the lowest single cell voltage and the lowest single cell temperature) are used to query the preset mapping table, and four current values can be obtained. The minimum current value is taken as the target current value to ensure compliance with safety requirements. Alternatively, the target current value can be obtained by querying the preset mapping table according to the single cell temperature and the state of charge SOC of the entire battery system. The target current value can be used as the maximum charging / discharging current of the battery under the current working condition to meet safety requirements, and the target current value can be used as the target output of the voltage conversion circuit.

[0054] The current regulation signal ISETx is an electrical signal corresponding to the target current value, which is an electrical signal representation of the target current value. The current regulation signal ISETx is used to adjust the current on the main circuit through the drive circuit 30.

[0055] The control circuit 20 performs closed-loop control on the actual current flowing through the current sampling resistor 10 (i.e., the actual current on the main circuit) from a software algorithm, mainly to adjust the current regulation signal ISETx to make ISETx more accurate. The software closed-loop control can compensate for the deviation of the device parameters of the hardware control chip LM5171 itself due to the influence of temperature, and can also compensate for the deviation of the actual current due to the influence of the temperature of the main circuit. Figure 1The 4-point cause (① the supply voltage precision of the micro control unit MCU in the control circuit 20 (such as 3V3 voltage precision or 5V voltage precision); ② the filtering precision of the second-order RC filter network; ③ the conduction voltage drop precision of the front-end diode of the ISETx voltage; ④ the voltage difference caused by the line impedance between the GND of the micro control unit MCU and the GND of the hardware control chip LM5171) of the error of the driving signal of the switch tube output by the special hardware control chip LM5171 described in the embodiment, so that the ISETx can be more accurate, and the hardware control chip LM5171 can more accurately control the switch tube in the voltage conversion circuit 40 to turn on or turn off at the right time, so that the actual current on the main circuit (the charge-discharge loop of the battery module) tends to be consistent with the target current value, ensuring the safety of battery charging and the reliability of the system.

[0056] The driving circuit 30 is configured to: collect the actual current flowing through the current sampling resistor 10, generate a driving signal based on the actual current and the current regulation signal ISETx, and the driving signal is used to drive the voltage conversion circuit 40, so that the current value of the actual current approximates the target current value.

[0057] Among them, the hardware circuit with closed-loop control included in the driving circuit 30 can realize hardware closed-loop control. The driving circuit 30 can compare two input signals (actual current and current regulation signal ISETx) based on the hardware circuit and adjust the output according to the error between the two, for example, the current regulation signal ISETx is a voltage signal, then the driving circuit 30 can compare the actual current converted into a voltage signal with the current regulation signal ISETx, so as to adjust the driving signal of the switch tube.

[0058] According to the battery management system provided in the embodiments of the present application, the battery management system 100 can include a current sampling resistor 10, a control circuit 20, a driving circuit 30 and a voltage conversion circuit 40. The current sampling resistor 10 is arranged on a main circuit, and the actual current of the main circuit can be obtained by collecting the actual current flowing through the current sampling resistor 10. The control circuit 20 is connected to the current sampling resistor 10. The driving circuit 30 is connected to the control circuit 20 and the current sampling resistor 10. The voltage conversion circuit 40 is connected to the driving circuit 30, and the voltage conversion circuit 40 is arranged on the main circuit. The control circuit 20 is configured to collect the actual current flowing through the current sampling resistor 10, read a target current value corresponding to the battery information based on the battery information, and generate an electric signal ISETx corresponding to the target current value (the electric signal can be referred to as a current adjustment signal) based on the difference between the current value of the actual current and the target current value, that is, the target current value is converted into a corresponding electric signal ISETx (such as a voltage signal). Subsequently, the driving circuit 30 can compare the current adjustment signal ISETx with the actual current, for example, if the current adjustment signal ISETx is a voltage signal, the current adjustment signal is compared with the voltage signal corresponding to the actual current. The driving circuit 30 is configured to collect the actual current flowing through the current sampling resistor 10, and generate a driving signal based on the actual current and the current adjustment signal, that is, the driving signal is obtained by the driving circuit 30 based on the feedback actual current for hardware closed-loop control, and the driving signal is used to drive the voltage conversion circuit 40 to adjust the actual current in the battery charging and discharging loop, so that the current value of the actual current approaches the target current value. Therefore, by combining software control (the actual current is fed back to the control circuit, and the control circuit adjusts the current adjustment signal corresponding to the target current value based on the feedback actual current for closed-loop control) and hardware control (the actual current is fed back to the driving circuit, and the driving circuit adjusts the driving signal of the switching tube based on the feedback actual current for closed-loop control), the control accuracy of the voltage conversion circuit is improved, the current value of the actual current on the main circuit approaches the target current value, and the fine control of the charging and discharging power is realized without increasing additional cost.

[0059] In some embodiments, as shown in Figure 4 The current sampling resistor 10 includes a first current sampling resistor R1 and a second current sampling resistor R2, The first current sampling resistor R1 is connected to the control circuit 20, and the second current sampling resistor R2 is connected to the driving circuit 30.

[0060] ​In this circuit, control circuit 20 and drive circuit 30 acquire the actual current in the main circuit through different sampling resistors. Therefore, the actual current acquired by control circuit 20 and drive circuit 30 also contains errors. Control circuit 20 performs closed-loop control based on the actual current in the main circuit using a software algorithm, adjusting the current regulation signal ISETx to achieve greater accuracy. The adjusted current regulation signal ISETx can compensate for: 1) The device parameters of the hardware control chip LM5171 itself are affected by temperature.

[0061] 2) such as Figure 1 The four reasons mentioned in the example are: (① the power supply voltage accuracy of the microcontroller unit MCU in the control circuit 20 (such as 3V3 voltage accuracy or 5V voltage accuracy); (② the filtering accuracy of the second-order RC filter network); (③ the forward voltage drop accuracy of the front-end diode of the ISETx voltage); (④ the voltage difference caused by the line impedance between the GND of the microcontroller unit MCU and the GND of the hardware control chip LM5171).

[0062] 3) The different sampling resistors connected to the control circuit 20 and the drive circuit 30 cause current sampling errors between the actual currents collected on the main circuit. The reason for compensating for these current sampling errors is that the actual current collected by the control circuit 20 is used as a reference (e.g., high-precision acquisition via an analog front-end circuit), and the duty cycle compensation amount ΔD is dynamically calculated through a software closed-loop control algorithm. Although there is a difference between the actual current value collected by the drive circuit (e.g., LM5171) through the second current sampling resistor R2 and the value collected by the control circuit 20 through the first current sampling resistor R1, the software algorithm incorporates this difference into the calculation of the duty cycle compensation amount ΔD, ultimately making the actual current value on the main circuit approach the target current value.

[0063] The adjusted current regulation signal ISETx enables the hardware control chip LM5171 to more accurately control the switching transistors in the voltage conversion circuit 40 to turn on or off at the appropriate time, so that the actual current in the main circuit (the charging and discharging circuit of the battery module) tends to be consistent with the target current value, ensuring battery charging safety and system reliability.

[0064] The control circuit 20 is specifically configured as follows: Based on battery information, the target current value is read from a preset mapping function; The duty cycle compensation amount (which can be denoted as ΔD) is calculated based on the difference between the actual current value and the target current value. Based on the duty cycle compensation amount ΔD and the initial duty cycle (which can be denoted as D0), a current regulation signal ISETx is generated, where the initial duty cycle D0 represents the duty cycle corresponding to the target current value.

[0065] In this context, the actual current value is a numerical value, and the target current value is also a numerical value. The control circuit 20 can directly calculate the difference between the actual current value and the target current value through a software algorithm, and calculate the duty cycle compensation amount ΔD based on the difference between the actual current value and the target current value. The duty cycle compensation amount ΔD is also a numerical value.

[0066] The initial duty cycle D0 is calculated by control circuit 20 based on the target current value.

[0067] The duty cycle compensation amount ΔD is used to adjust the initial duty cycle D0 to obtain the target duty cycle D0'. For example, if the initial duty cycle D0 is 0.3 and the duty cycle compensation amount ΔD is 0.1, then the target duty cycle D0' = 0.3 + 0.1 = 0.4. As another example, if the initial duty cycle D0 is 0.3 and the duty cycle compensation amount ΔD is -0.1, then the target duty cycle D0' = 0.3 + (-0.1) = 0.2.

[0068] For example, the control circuit 20 calculates the duty cycle compensation amount ΔD through a software algorithm, and adjusts the initial duty cycle D0 based on the duty cycle compensation amount ΔD to obtain the target duty cycle D0'. Then, it generates a two-level electrical signal with the target duty cycle D0' according to the internal two-level electrical signal generation circuit. The discrete digital signal with the target duty cycle D0' is then converted into a continuous analog voltage signal (i.e., the current adjustment signal ISETx) through the internal filtering circuit. This signal is used by the drive circuit 30 to compare the current adjustment signal ISETx with the actual continuous analog voltage signal (the voltage signal corresponding to the actual current) through the internal hardware circuit (such as a voltage comparator).

[0069] In one example, a preset mapping function can determine the target current value based on the temperature and voltage of a single cell. For instance, the preset mapping function can correspond to four current values ​​from four combinations (highest single cell voltage and highest single cell temperature, highest single cell voltage and lowest single cell temperature, lowest single cell voltage and highest single cell temperature, and lowest single cell voltage and lowest single cell temperature), and take the minimum current value as the target current value to ensure compliance with safety requirements. Alternatively, the preset mapping function can also determine the target current value based on the temperature of a single cell and the state of charge (SOC) of the entire battery system. Using the target current value as the maximum charging / discharging current of the battery under the current operating conditions can meet safety requirements, and the target current value can be used as the target output of the voltage conversion circuit.

[0070] This embodiment of the application achieves independent acquisition of the main circuit current by the control circuit 20 and the drive circuit 30 through a dual current sampling resistor design. Combined with the software closed-loop control algorithm of the control circuit 20, the current regulation signal ISETx is dynamically adjusted, which can effectively compensate for multiple sources of errors such as temperature drift of the hardware control chip LM5171, power supply voltage accuracy error of the microcontroller unit MCU in the control circuit 20, filter network deviation, diode voltage drop difference, ground voltage difference, and current sampling difference caused by different sampling resistors. Ultimately, the drive circuit 30 (including the hardware control chip, such as LM5171) accurately controls the switching of the switching transistor in the voltage conversion circuit, ensuring that the actual current value of the main circuit is highly consistent with the target current value, significantly improving battery charging safety and system reliability.

[0071] In some embodiments, The drive circuit 30 is specifically configured as follows: The difference between the voltage value represented by the voltage signal (which is derived from the actual current and therefore represents the sampled actual current) and the voltage value represented by the current regulation signal is used to generate a drive signal through the closed-loop control of the drive circuit 30.

[0072] In other words, the physical essence of the current regulation signal ISETx is to convert the target current value into a voltage signal. For example, the voltage value of the current regulation signal ISETx is 1.1V. The drive circuit 30 compares the voltage value of 1.1V represented by the current regulation signal ISETx with the voltage value of the voltage signal obtained by converting the actual current (e.g., 1V, where 1V represents the sampled actual current) through its internal hardware circuit (hardware control chip, such as LM5171). The difference between the two is 0.1V. Then, 0.1V is used as the compensation amount of the drive signal to compensate the original drive signal, thereby obtaining the compensated drive signal and realizing the closed-loop control of the hardware.

[0073] The driving circuit 30 in this embodiment compares the difference between the current adjustment signal ISETx (the voltage expression of the target current) and the voltage signal converted from the actual current (the voltage expression of the actual current) through closed-loop control of the hardware circuit, and generates a driving signal based on the difference. This can meet the requirements of high dynamic and high precision control, and can quickly and accurately control the on and off of the switching transistor to ensure that the actual current of the main circuit is consistent with the target current.

[0074] In some embodiments, such as Figure 5 As shown, The control circuit 20 may include an analog front-end circuit 21 and a microcontroller unit 22. The analog front-end circuit 21 is connected to the battery module 200 and the current sampling resistor 10, and the microcontroller unit 22 is connected to the analog front-end circuit 21.

[0075] The analog front-end circuit 21 can acquire the actual voltage across the current sampling resistor 10, and then divide the actual voltage across the current sampling resistor 10 by the resistance value of the current sampling resistor 10 to obtain the current value of the actual current flowing through the current sampling resistor 10.

[0076] In one example, the analog front-end circuit 21 can also be connected to the battery module 200, enabling it to collect information such as the temperature and voltage of individual cells, and send the collected information (such as the actual current value flowing through the current sampling resistor 10, the temperature of individual cells, and the voltage of individual cells) to the microcontroller unit 22. The microcontroller unit 22 can read the target current value based on the battery information; therefore, the microcontroller unit 22 can obtain the target current value and the actual current value through the analog front-end circuit 21.

[0077] The battery management system 100 may also include a filter circuit 50, which is connected to the microcontroller unit 22 and the drive circuit 30.

[0078] The microcontroller unit 22 is configured to: acquire a target current value, calculate a duty cycle compensation amount ΔD based on the difference between the actual current value and the target current value, adjust the initial duty cycle D0 based on the duty cycle compensation amount ΔD to obtain a target duty cycle D0', and generate an electrical signal with the target duty cycle D0' (for example, the electrical signal has only high and low levels, that is, a two-level electrical signal, and the duty cycle of the electrical signal is the target duty cycle D0').

[0079] The filter circuit 50 is configured to filter the electrical signal with the target duty cycle D0' to obtain the current regulation signal ISETx.

[0080] The initial duty cycle D0 represents the duty cycle corresponding to the target current value. The initial duty cycle D0 is calculated based on the target current value.

[0081] The filter circuit 50 converts the discrete digital signal, a two-level electrical signal with a target duty cycle D0', into a continuous analog voltage signal (i.e., the current adjustment signal ISETx) through an internal filter circuit. This signal is then used by the drive circuit 30 to compare the current adjustment signal ISETx with the actual continuous analog voltage signal (the voltage signal corresponding to the actual current) through an internal hardware circuit (such as a voltage comparator).

[0082] In other words, the current regulation signal ISETx can be directly output by the microcontroller unit 22; or it can be generated by the microcontroller unit 22 in conjunction with an external filter circuit 50. After the microcontroller unit 22 generates a two-level digital signal, the waveform is converted and noise is suppressed by the external optional filter circuit 50 (such as a second-order RC filter network or an integrated filter module), and finally a continuous analog voltage signal (i.e., the current regulation signal ISETx) is output. The external filter circuit 50 can further improve the signal quality and achieve higher accuracy. The two solutions can be flexibly selected according to accuracy requirements, cost constraints, or space limitations.

[0083] This embodiment of the application achieves high-precision synchronous acquisition of multiple parameters such as current, voltage, and temperature through the analog front-end circuit 21. Combined with the software closed-loop control algorithm of the microcontroller unit 22, the duty cycle compensation amount ΔD is calculated based on the difference between the actual current value and the target current value, and a target duty cycle signal D0' is generated. This signal is then converted into a continuous analog voltage signal ISETx by the filter circuit 50, forming a full-link closed-loop control of "sampling-calculation-compensation-conversion". This effectively compensates for deviations such as hardware errors and environmental factors, ensuring a high degree of matching between the actual current and the target current in the main circuit. This significantly improves the current regulation accuracy and provides a solid guarantee for battery charging and discharging safety and system reliability.

[0084] In some embodiments, The microcontroller is specifically configured to: multiply the duty cycle compensation amount ΔD by a preset influence factor to obtain the target compensation amount, and add the target compensation amount to the initial duty cycle D0 to obtain the target duty cycle D0'.

[0085] The preset impact factor represents the weight of the software algorithm, and the preset impact factor can be set according to actual needs.

[0086] For example, if the duty cycle compensation amount ΔD is 0.2 and the preset influence factor is 0.1, then the target compensation amount = 0.2 × 0.1 = 0.02. If the initial duty cycle D0 is 0.3, then the target duty cycle D0' = 0.3 + 0.02 = 0.32.

[0087] This application embodiment introduces a preset influence factor to weight and adjust the duty cycle compensation amount, realizing the flexible configurability of the software algorithm compensation. The compensation weight can be dynamically adjusted according to the actual working conditions, enhancing the precision control of current regulation, improving the system's adaptability to multiple scenarios, effectively balancing the compensation intensity and system stability, and ultimately achieving more precise closed-loop control of the main circuit current, ensuring battery safety and system reliability.

[0088] In some embodiments, The microcontroller is specifically configured to: generate an electrical signal with the target duty cycle in response to a target duty cycle being less than or equal to a preset duty cycle threshold, and generate an electrical signal with the duty cycle threshold in response to a target duty cycle being greater than the duty cycle threshold.

[0089] The preset duty cycle threshold is used to limit the amplitude of the target duty cycle and avoid the risk of overshoot caused by the failure of the software control algorithm of the microcontroller unit 22. The preset duty cycle threshold can be set according to actual needs.

[0090] In other words, the duty cycle of the two-level signal output by the microcontroller 22 cannot exceed the duty cycle threshold. After determining the target duty cycle, it is necessary to compare the target duty cycle with the duty cycle threshold. If the target duty cycle is less than the threshold, it means that the software control algorithm of the microcontroller 22 has not failed, and it can output normally; if the target duty cycle is greater than the threshold, it means that the software control algorithm of the microcontroller 22 has failed, and the duty cycle of the two-level signal output by the microcontroller 22 can only be equal to the duty cycle threshold at most.

[0091] This application embodiment achieves intelligent limiting protection by preset duty cycle threshold. When the target duty cycle is within the safe range, it outputs normally. When it exceeds the threshold, it automatically clamps to the threshold, effectively preventing the risk of over-adjustment caused by software algorithm failure. This not only ensures accurate control under normal operating conditions, but also avoids device damage or system instability caused by abnormal increase in duty cycle in extreme cases, significantly improving the safety redundancy and operational reliability of the battery management system.

[0092] In some embodiments, such as Figure 6 As shown, the filter circuit 50 may include a first filter sub-circuit 51, a second filter sub-circuit 52, and a diode 53.

[0093] The first filter circuit 51 is connected to the microcontroller unit.

[0094] The second filter circuit 52 is connected to the first filter circuit 51.

[0095] The anode of diode 53 is connected to the second filter circuit 52, and the cathode of diode 53 is connected to the drive circuit 30.

[0096] The filter circuit 50 provided in this embodiment achieves multi-level signal smoothing through two-stage filter sub-circuits (first filter sub-circuit 51 and second filter sub-circuit 52), effectively reducing noise and ripple in the digital-to-analog signal conversion process, improving the purity of the current regulation signal ISETx, and at the same time, the diode 53 can prevent reverse current surges, protect the drive circuit 30 from abnormal voltage, and stabilize the auxiliary voltage, significantly enhancing the anti-interference capability and accuracy of the current regulation signal, and ensuring the stable operation and precise current control of the battery management system under complex operating conditions.

[0097] In one example, the drive circuit 30 uses a dedicated DC-DC control chip LM5171. The equivalent diagram of the single-phase current loop control of the DC-DC control chip LM5171 operating in buck mode is shown below. Figure 7 As shown, VHV is the input of the main circuit, VLV is the output of the main circuit, Lm is the power inductor (the inductor in a general-purpose BOOST / BUCK circuit), Rcs is the current sampling resistor, and C... OUT_BK In buck mode, is the total output capacitor, and RESR_BK is the equivalent series resistance of the total output capacitor. The current regulation signal ISETx serves as the loop reference for the LM5171, obtained by the microcontroller unit through software closed-loop control. The LM5171 has an internal current sampling circuit that can acquire the actual current of the main circuit through the current sampling resistor Rcs. Gm can calculate the difference between the two input voltages, that is, the voltage value represented by the current regulation signal ISETx and the voltage value represented by the actual current, to obtain the voltage error value. The internal circuit of the LM5171 can compensate the original drive signal based on the voltage error value, generate a new drive signal PWM, and output it to control the switching transistor in the voltage conversion circuit 40 to turn on or off.

[0098] This application's embodiments employ a control algorithm combining hardware and software, which not only improves efficiency and control precision but also allows for real-time adaptation to changes in system operating conditions. Without adding additional steps, it achieves refined control of charging and discharging power; significantly improving battery usability and safety while also extending its lifespan.

[0099] In some embodiments, such as Figure 8 As shown, the voltage conversion circuit 40 may include N voltage conversion sub-circuits 41, where N is an integer greater than or equal to 1.

[0100] N voltage conversion sub-circuits 41 are connected in parallel, and the voltage conversion sub-circuits 41 are connected to the drive circuit 30.

[0101] Where N is the number of voltage conversion sub-circuits 41, the number of which can be set according to actual needs.

[0102] For example, such as Figure 9 As shown, N is 4, and the four voltage conversion sub-circuits 41 are connected in parallel. The driving circuit 30 can provide an independent driving signal for each voltage conversion sub-circuit 41.

[0103] In this embodiment, the total power handling capacity of the voltage conversion circuit 40 can be improved by connecting the parallel voltage conversion sub-circuits 41. At the same time, the drive circuit 30 can provide an independent drive signal for each voltage conversion sub-circuit 41. The independent drive signal supports precise current distribution and dynamic balance control, which can achieve highly reliable and scalable voltage conversion and adapt to different power levels and complex operating conditions.

[0104] In some embodiments, see [link to relevant documentation]. Figure 8 or Figure 9 , The phase difference between the N drive signals output by the drive circuit 30 is 2π / N.

[0105] For example, such as Figure 9 As shown, four voltage conversion sub-circuits 41 are connected in parallel. Each voltage conversion sub-circuit 41 is a BUCK circuit. The drive circuit 30 can provide a different phase drive signal PWM for each voltage conversion sub-circuit 41, which can be called a four-phase interleaved parallel BUCK circuit. The drive circuit 30 includes two DC-DC control chips LM5171. The input to both LM5171 is a current regulation signal ISETx. One LM5171 can control two voltage conversion sub-circuits 41. For example, the phase difference between the four drive signals is 2π / 4. Among the four drive signal PWM signals, one drive signal has a peak value of 0°, one drive signal has a peak value of 90°, one drive signal has a peak value of 180°, and another drive signal has a peak value of 270°. The current from the four voltage conversion sub-circuits 41 is superimposed to form the main circuit current.

[0106] For example, such as Figure 10 As shown, the currents in the four-channel voltage conversion sub-circuit 41 are IL1, IL2, IL3 and IL4, respectively. The superposition of the four currents results in the main circuit current Iout, which significantly reduces the current ripple of the main circuit.

[0107] This application embodiment achieves both ripple suppression and power density improvement through a multi-phase interleaved parallel BUCK circuit. The N-channel drive signals adopt a 2π / N phase difference (e.g., 0° / 90° / 180° / 270° staggered peaks in four-phase circuits), which cancels out the peak / valley current values ​​of each voltage conversion sub-circuit 41. After superposition, the ripple of the main circuit current Iout is significantly reduced. At the same time, the parallel structure effectively improves the total power handling capacity. Combined with the design of dual LM5171 chips independently controlling the two voltage conversion sub-circuits 41, efficient current distribution and dynamic balance are achieved. Ultimately, while ensuring high-precision current regulation, the hardware redundancy and phase interleaving technology can meet the requirements of low ripple and high reliability.

[0108] It should be noted that the embodiments of this application, through the combined action of software loop correction and hardware loop, can eliminate the error of single hardware loop control, and can make the actual current value on the main circuit infinitely close to the target current value.

[0109] Based on the same inventive concept, such as Figure 11 As shown, this application embodiment also provides a battery system 1000, including a battery module 200 and the battery management system 100 described in any of the above embodiments.

[0110] The battery system 1000 includes the battery management system 100 provided in any of the above embodiments, and therefore the battery system 1000 has all the beneficial effects of the battery management system 100.

[0111] Based on the same inventive concept, such as Figure 12 As shown, this application embodiment also provides an electrical device 2000, including the battery system 1000 described in any of the above embodiments.

[0112] The power-consuming device 2000 includes the battery system 1000 described in any of the above embodiments, and the battery system 1000 includes the battery management system 100 provided in any of the above embodiments. Therefore, the power-consuming device 2000 has all the beneficial effects of the battery management system 100 described above.

[0113] It should be noted that in the embodiments shown in the figures above, the resistor is presented as a single resistor, and the capacitor as a single capacitor. In other embodiments, the resistor may be an integrated combination of series, parallel, or mixed resistors, and the capacitor may be an integrated combination of series, parallel, or mixed capacitors. The specific parameters of each device can be set according to actual needs, and this application does not limit this.

[0114] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered 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 battery management system, characterized in that, include: The current sampling resistor is set on the main circuit; The control circuit is connected to the current sampling resistor; The driving circuit is connected to the control circuit and the current sampling resistor; A voltage conversion circuit is connected to the drive circuit, and the voltage conversion circuit is disposed on the main circuit; The control circuit is configured to: acquire the actual current flowing through the current sampling resistor, read the target current value corresponding to the battery information based on the battery information, and generate a current adjustment signal based on the actual current value and the target current value; The driving circuit is configured to: acquire the actual current flowing through the current sampling resistor, generate a driving signal based on the actual current and the current adjustment signal, and use the driving signal to drive the voltage conversion circuit so that the current value of the actual current approaches the target current value. The battery information includes battery temperature and battery voltage, or the battery information includes battery temperature and battery SOC.

2. The battery management system according to claim 1, characterized in that, The current sampling resistor includes a first current sampling resistor and a second current sampling resistor. The first current sampling resistor is connected to the control circuit, and the second current sampling resistor is connected to the drive circuit; The control circuit is specifically configured as follows: Based on the battery information, the target current value is read from a preset mapping function; The duty cycle compensation is calculated based on the difference between the actual current value and the target current value. The current adjustment signal is generated based on the duty cycle compensation amount and the initial duty cycle, wherein the initial duty cycle represents the duty cycle corresponding to the target current value.

3. The battery management system according to claim 1 or 2, characterized in that, The driving circuit is specifically configured as follows: The driving signal is generated based on the difference between the voltage value represented by the voltage signal and the voltage value represented by the current regulation signal, through closed-loop control of the driving circuit.

4. The battery management system according to any one of claims 1-3, characterized in that, The control circuit includes an analog front-end circuit and a microcontroller unit, wherein the analog front-end circuit is connected to the battery and the current sampling resistor, and the microcontroller unit is connected to the analog front-end circuit controller; The battery management system includes: a filter circuit, which is connected to the microcontroller unit and the drive circuit; The microcontroller unit is configured to: acquire the target current value, calculate a duty cycle compensation amount based on the difference between the actual current value and the target current value, adjust the initial duty cycle based on the duty cycle compensation amount to obtain the target duty cycle, and generate an electrical signal with the target duty cycle. The filtering circuit is configured to filter an electrical signal having the target duty cycle to obtain the current regulation signal. The initial duty cycle represents the duty cycle corresponding to the target current value.

5. The battery management system according to any one of claims 2-4, characterized in that, The microcontroller unit is specifically configured to: multiply the duty cycle compensation amount by a preset influence factor to obtain a target compensation amount, and add the target compensation amount to the initial duty cycle to obtain a target duty cycle.

6. The battery management system according to claim 5, characterized in that, The microcontroller unit is specifically configured to: generate an electrical signal having the target duty cycle in response to the target duty cycle being less than or equal to a preset duty cycle threshold, and generate an electrical signal having the duty cycle threshold in response to the target duty cycle being greater than the duty cycle threshold.

7. The battery management system according to any one of claims 4-6, characterized in that, The filtering circuit includes: The first filter circuit is connected to the microcontroller unit; The second filter sub-circuit is connected to the first filter sub-circuit; A diode, wherein the anode of the diode is connected to the second filter sub-circuit, and the cathode of the diode is connected to the drive circuit.

8. The battery management system according to any one of claims 1 to 7, characterized in that, The voltage conversion circuit includes N voltage conversion sub-circuits, where N is an integer greater than or equal to 1; N voltage conversion sub-circuits are connected in parallel, and the voltage conversion sub-circuits are connected to the drive circuit.

9. The battery management system according to claim 8, characterized in that, The phase difference between the N driving signals output by the driving circuit is 2π / N.

10. A battery system, characterized in that, Includes a battery module and a battery management system as described in any one of claims 1 to 9.

11. An electrical appliance, characterized in that, Includes the battery system as described in claim 10.

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