Battery Management System for Detecting Abnormal Voltage

Abstract

A battery management system for detecting abnormal voltage according to the present invention comprises an Infinite Impulse Response (IIR) filter that determines the current output voltage by adding a value obtained by multiplying the difference between the current input voltage and the output voltage from one cycle prior by a filter coefficient to the output voltage from one cycle prior, a comparator that outputs a result of comparing the difference between the current input voltage and the input voltage from one cycle prior with a limit voltage, and a multiplexer that selects and outputs one of the current output voltage of the IIR filter and the current input voltage according to the output result of the comparator. This battery management system can rapidly detect abnormal conditions when measuring voltage and can rapidly prevent the spread of abnormalities to a battery module or battery pack by rapidly recognizing and removing a battery cell indicating an abnormal condition.

Description

Technology Field

[0001] The present invention relates to a battery management system, and more specifically, to a battery management device equipped with a function to detect abnormal voltage of a battery or fuel cell. Background Technology

[0003] Unlike conventional internal combustion engine vehicles, electric vehicles operate by obtaining driving energy from electrical energy stored in battery cells rather than fossil fuels.

[0004] In order to provide high voltage used in a vehicle, a plurality of battery cells can be connected in series to form a battery module, and battery modules can be connected in series to form a battery pack.

[0005] The Battery Management System (BMS) that manages the batteries of electric vehicles monitors the battery's charging and discharging status, current voltage, and current, and plays a role in adjusting the cells to maintain uniform voltage and state in the event of cell imbalance. To perform this role, the BMS senses and stores various information, such as the voltage, current, and temperature of the battery cells, through the cell monitoring process.

[0006] When a battery management system measures battery cell information, various types of noise caused by the external environment (temperature, humidity, vibration, shock, etc.) may be inserted during measurement, thereby distorting the battery cell information. Due to this distortion, a battery providing normal voltage may be judged to be operating abnormally, or a battery operating abnormally may be judged to be operating normally.

[0007] In addition, digital filters used to remove noise causing distortion from measured signals may reduce the signal magnitude during distortion correction or cause time delays during the filtering process. The problem to be solved

[0009] The present invention proposes a battery management system capable of detecting abnormal voltage while resolving the problem of signal magnitude reduction or time delay caused by a filter used to correct a signal distorted by noise during battery cell voltage measurement, which is intended to solve the aforementioned problem.

[0010] The technical problems intended to be solved in this document are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below. means of solving the problem

[0012] According to various embodiments, a battery management system for detecting overvoltage may include an Infinite Impulse Response (IIR) filter that determines a current output voltage by adding a current input voltage and a value obtained by multiplying the output voltage from one cycle prior by a filter coefficient to an output voltage from one cycle prior; a comparator that outputs a result of comparing the difference between the current input voltage and the input voltage from one cycle prior with a limit voltage; and a multiplexer that selects and outputs one of the current output voltage of the IIR filter and the current input voltage according to the output result of the comparator.

[0013] According to one embodiment, if the difference between the input voltage from one cycle prior and the current measured voltage is greater than the limit voltage, a first value is output, and if the difference between the input voltage from one cycle prior and the current measured voltage is less than the limit voltage, a second value different from the first value is output, and the multiplexer can select and output the current input voltage when receiving the first value as a selection input, and select and output the output voltage of the IIR filter when receiving the second value as a selection input.

[0014] According to one embodiment, the comparator may output the first value immediately when the output value changes from the second value to the first value, and output the second value with a one-cycle delay when the output value changes from the first value to the second value.

[0016] According to various other embodiments, the apparatus may include a moving average filter that averages and outputs input voltages input over a plurality of consecutive cycles, a comparator that outputs a result of comparing the difference between the input voltage one cycle prior and the current input voltage with a threshold voltage, and a multiplexer that selects and outputs one of the output voltage of the moving average filter and the current input voltage according to the output result of the comparator.

[0017] According to one embodiment, the comparator outputs a first value when the difference between the input voltage one cycle prior and the current measured voltage is greater than the limit voltage, and outputs a second value different from the first value when the difference between the input voltage one cycle prior and the current measured voltage is less than the limit voltage, and the multiplexer can select and output the current input voltage when receiving the first value as a selection input, and select and output the output voltage of the moving average filter when receiving the second value as a selection input.

[0018] According to one embodiment, the moving average filter is configured such that a plurality of delay buffers are connected in a sequence, and in each cycle, the first delay buffer among the plurality of delay buffers receives and stores the current input voltage, and the remaining delay buffers among the plurality of delay buffers, excluding the first delay buffer, receive and store the value stored in the preceding delay buffer, and calculate and output the average of the value stored in the plurality of delay buffers and the current input voltage.

[0019] According to one embodiment, the comparator may output the first value immediately when the output value changes from the second value to the first value, and output the second value after delaying it by a number of cycles equal to the number of delay buffers when the output value changes from the first value to the second value.

[0020] According to one embodiment, the comparator may not execute the output of the second value and may maintain the output of the first value as is when the output value changes from the second value to the first value while the output value is delayed as the output value changes from the first value to the second value.

[0021] According to another embodiment, a method for a battery management system to detect an abnormal voltage may include the steps of: determining the current output voltage of an IIR (Infinite Impulse Response) filter by adding a value obtained by multiplying the difference between the current input voltage and the output voltage one cycle prior by a filter coefficient to the output voltage one cycle prior; outputting a result of comparing the difference between the current input voltage and the input voltage one cycle prior with a limit voltage; and selecting and outputting one of the current output voltage of the IIR filter and the current input voltage according to the result of the comparison.

[0022] According to one embodiment, the step of outputting a result of comparing the difference between the current input voltage and the input voltage from one cycle prior with a limit voltage is to output a first value when the difference between the input voltage from one cycle prior and the current measured voltage is greater than the limit voltage, and to output a second value different from the first value when the difference between the input voltage from one cycle prior and the current measured voltage is less than the limit voltage. The step of selecting and outputting one of the current output voltage of the IIR filter and the current input voltage according to the result of the comparison is to select and output the current input voltage when the first value is received as a selection input, and to select and output the output voltage of the IIR filter when the second value is received as a selection input.

[0023] According to one embodiment, the step of outputting the result of comparing the difference between the current input voltage and the input voltage from one cycle prior with the limit voltage may output the first value immediately when the output value changes from the second value to the first value, and output the second value with a one-cycle delay when the output value changes from the first value to the second value.

[0024] According to another embodiment, the method may include the steps of determining the current output voltage of a moving average filter that averages input voltages input over a plurality of consecutive cycles, determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with a limit voltage, and selecting and outputting one of the output voltage of the moving average filter and the current input voltage according to the output result of the comparator.

[0025] According to one embodiment, the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage comprises outputting a first value when the difference between the input voltage one cycle prior and the current measured voltage is greater than the limit voltage, and outputting a second value different from the first value when the difference between the input voltage one cycle prior and the current measured voltage is less than the limit voltage, and selecting and outputting one of the output voltage of the moving average filter and the current input voltage according to the comparator output result, wherein when the first value is received as a selection input, the current input voltage is selected and output, and when the second value is received as a selection input, the output voltage of the moving average filter is selected and output.

[0026] According to one embodiment, the method comprises the step of determining the current output voltage of a moving average filter that averages and outputs input voltages received in a plurality of consecutive cycles, wherein a plurality of delay buffers are connected in a sequence and, for each cycle, the first delay buffer among the plurality of delay buffers receives and stores the current input voltage, and the remaining delay buffers among the plurality of delay buffers, excluding the first delay buffer, receive and store the value stored in the preceding delay buffer, and calculate and output the average of the value stored in the plurality of delay buffers and the current input voltage.

[0027] According to one embodiment, the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage may be such that if the output value changes from the second value to the first value, the first value is output immediately, and if the output value changes from the first value to the second value, the second value is output after delaying by a number of cycles equal to the number of delay buffers.

[0028] According to one embodiment, the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage may, when the output value changes from the second value to the first value while the output of the second value is being delayed as the output value changes from the first value to the second value, not execute the output of the second value and maintain the output of the first value as is. Effects of the invention

[0030] According to various embodiments, the battery management system can quickly detect abnormal situations when measuring voltage.

[0031] According to various embodiments, the battery management system can quickly prevent the spread of abnormalities to the battery module or battery pack by quickly recognizing and removing a battery cell indicating an abnormal condition.

[0032] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure pertains from the description below. Brief explanation of the drawing

[0034] Figure 1 is a diagram illustrating a Battery Monitor Integrated Circuit (BMIC) connected to a battery module composed of multiple battery cells. Figure 2 is an example showing the noise filtering results in an IIR (Infinite Impulse Response) filter or a Moving Average filter. Figure 3 is an example diagram showing the result of filtering out abnormal transfers in an IIR filter or a moving average filter. Figure 4 is a diagram illustrating an IIR filter. Figure 5 is a diagram showing the result of filtering the overvoltage through the IIR filter of Figure 4. FIG. 6 is a diagram illustrating an IIR filter that adds a path for the input to bypass the filter when an overvoltage is detected, according to various embodiments of the present invention. FIG. 7 is a diagram illustrating the filtering result of an IIR filter that adds a path for the input to bypass the filter when an overvoltage is detected, according to various embodiments of the present invention. Figure 8 is a diagram illustrating a moving average filter. Figure 9 is a diagram showing the result of filtering the abnormal voltage through the moving average filter of Figure 7. FIG. 10 is a diagram illustrating a moving average filter that adds a path for the input to bypass the filter when an abnormal voltage is detected, according to various embodiments of the present invention. FIG. 11 is a diagram illustrating the result of filtering a moving average filter with an additional path that bypasses the filter when an input detects an abnormal voltage according to various embodiments of the present invention. Specific details for implementing the invention

[0035] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, like reference numerals refer to like components.

[0036] When one component is referred to as being "connected to" or "coupled to" another component, it includes cases where it is directly connected or coupled to the other component, or cases where another component is interposed. Conversely, when one component is referred to as being "directly connected to" or "directly coupled to" another component, it indicates that no other component is interposed. "And / or" includes each of the mentioned items and all combinations of one or more of them.

[0037] The terms used herein are for describing embodiments and are not intended to limit the disclosure. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0038] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another.

[0039] Therefore, it is obvious that the first component mentioned below may be the second component within the technical scope of this disclosure. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which this disclosure pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0040] The terms 'part' or 'module' as used in this embodiment refer to software or hardware components such as FPGAs or ASICs, and the 'part' or 'module' performs certain roles. However, the meaning of 'part' or 'module' is not limited to software or hardware. The 'part' or 'module' may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the 'part' or 'module' may include components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided within the 'part' or 'module' may be combined into a smaller number of components and 'part' or 'module', or further separated into additional components and 'part' or 'module'.

[0041] Steps of a method or algorithm described in connection with some embodiments of the present disclosure may be directly implemented in hardware, software modules, or a combination of both, executed by a processor. Software modules may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of recording medium known in the art. An exemplary recording medium is coupled to a processor, and the processor can read information from the recording medium and write information to the storage medium. Alternatively, the recording medium may be integral with the processor. The processor and the recording medium may reside within an Application-Specific Integrated Circuit (ASIC). The ASIC may reside within a user terminal.

[0042] Hereinafter, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0044] Figure 1 is a diagram illustrating a Battery Monitor Integrated Circuit (BMIC) connected to a battery module composed of multiple battery cells.

[0045] Referring to FIG. 1, a battery module (100) may be composed of a plurality of battery cells (110) connected in series. A battery system in the field of eco-friendly energy vehicles, such as electric vehicles and hydrogen vehicles, may be able to provide a high voltage by forming a battery module (100) by connecting a plurality of battery cells (110) in series and providing a battery pack formed by connecting a plurality of battery modules (100) in series. FIG. 1 is exemplarily shown in which N battery cells (110) are connected in series to a single battery module (100) to form N channels (Ch1, ..., Chn It is composed of ), and the number of battery cells (110) in one battery module (100) can be set differently considering the voltage that the battery system must supply, the stability of the system, etc.

[0046] Referring to FIG. 1, the BMIC (200) may be composed of a monitoring unit (210) that is connected to each of N battery cells (110) to measure data of each battery cell (110), a processing unit (220) that processes the battery cell (110) data transmitted by the monitoring unit (210), and a communication unit (230) that can communicate with an adjacent BMIC (200) or a host MCU.

[0047] The monitoring unit (210) can be connected to the battery cell (110). The monitoring unit (210) can measure information such as the voltage, current, and temperature of the battery cell (110) and provide information to the calculation unit (220) that can monitor the battery cell (110).

[0048] The processing unit (220) can process battery cell (110) information and transmit it to the communication unit (230). At this time, the battery cell (110) information provided by the monitoring unit (210) can be used by the processing unit (220) to determine whether there is an abnormality in the battery cell (210) voltage, and a process of removing noise from the battery cell (110) voltage using an IIR (Infinite Impulse Response) filter or a moving average filter may be required.

[0049] The communication unit (230) can transmit battery cell (110) information processed by the operation unit (230) to the host MCU (Micro Controller Unit) or receive commands from the host MCU.

[0050] Figure 2 is an example showing the result of noise filtering in an IIR (Infinite Impulse Response) filter or a moving average filter, and Figure 3 is an example showing the result of overvoltage being filtered in an IIR filter or a moving average filter.

[0051] Referring to FIGS. 2 and 3, when a measurement signal is filtered using an IIR filter and a moving average filter, which are most commonly used when measuring voltage in a general Battery Management System (BMS), it can be observed that when noise and abnormal voltage pass through the filter, the magnitude of the signal decreases and a delay in the response signal occurs.

[0052] In a battery management system, battery or fuel cell voltage measurements can be performed at cycles of 50ms to 200ms. Consequently, when a filter is used at the downstream end, detection of sudden voltage fluctuations may occur after several cycles, although this varies depending on the type of filter. Furthermore, the detected value may be smaller than the actual value, which can lead to differences in severity.

[0053] In the case of currently most widely used IIR filters or moving average filters, detection becomes possible after approximately 10 cycles or more have passed since the occurrence of abnormal operation. When converted to time, this corresponds to a point in time of about 0.5 to 2 seconds, during which time phenomena such as thermal runaway may occur in batteries.

[0054] The reasons for the time delay occurring in these IIR filters and moving average filters are as follows.

[0055] IIR filters utilize a feedback structure that allows them to perform filtering by considering both past and current input values. Consequently, while they offer significant noise reduction in the measurement signal, the output signal may change slowly due to the continuous incorporation of past data, and abnormal voltages may only be detected after several measurements.

[0056] Moving average filters determine the size of the window used for filtering and provide the average of the input data as an output. While they offer significant noise reduction depending on the window size, they may not provide accurate values ​​until data has accumulated, which can lead to reduced sensitivity to signal changes. In other words, detection of abnormal voltage caused by rapid voltage fluctuations is only possible after a certain number of measurement data points have been accumulated in the filter register. Furthermore, since the output value is generated based on the average even when abnormal voltage occurs, it changes gradually, making it difficult to respond immediately to the detection of instantaneous abnormal voltages.

[0057] Accordingly, the present invention relates to a method and circuit that can compensate for the time delay problem that may occur when detecting abnormal voltage in an IIR filter and a moving average filter, which are commonly used when measuring the voltage of a battery cell (110) in a battery management system.

[0058] Figure 4 is a diagram showing an IIR filter, and Figure 5 is a diagram showing the result of filtering abnormal voltage through an IIR filter.

[0059] The IIR filter (300) of FIG. 4 may be Y[n] = A(X[n] - Y[n-1]) + Y[n-1]. Here, Y[n] may be the current output value (result value), X[n] may be the current input value (current measurement data), Y[n-1] may be the previous output value (result value), and A may be the filter coefficient (attenuation coefficient).

[0060] Referring to FIG. 4, the subtractor (310) delays the current input value (X[n]) of the IIR filter (300) by the delay buffer (Z -1 The previous output value (Y[n-1]) stored in ) can be subtracted. That is, the subtractor (310) can perform the operation X[n]-Y[n-1]. The output of the subtractor (310) can be output after being multiplied by the filter coefficient A in the multiplier (320). Accordingly, the output of the multiplier (320) can be A(X[n]-Y[n-1]). The output of the multiplier (320) is input to the adder (330). In the adder (330), the delay buffer (Z -1 The output signal (Y[n]) can be generated by adding it to the previous output value (Y[n-1]) stored in ). That is, the result Y[n] = A(X[n] - Y[n-1]) + Y[n-1] can be output.

[0061] The IIR filter (300) can detect abnormal voltage by calculating the difference between the input signal and the output signal, and can optimize abnormal voltage detection and noise removal performance by adjusting the filter coefficient (A). In addition, since the structure is very simple, it can be implemented with a small amount of computation, which can be advantageous for systems requiring real-time processing.

[0062] Adjusting the filter coefficient (A) allows for simple transmission, that is, outputting the original signal as is without filtering, when the filter coefficient (A) is 1. As the filter coefficient (A) becomes smaller, the amount of change in the output signal decreases and the noise removal effect increases, but there may be a disadvantage of a slower response speed. Finally, as the filter coefficient (A) becomes larger, the amount of change in the output signal increases and the response speed increases, but the noise removal effect may decrease.

[0063] Since the IIR filter (300) has a feedback structure, it can become unstable depending on the coefficient values ​​and may cause divergence problems. In addition, to stabilize the output signal, the smaller the filter coefficient (A), the slower the signal changes, which may slow down the speed at which abnormal voltage is detected when monitoring battery cell voltage in a battery management system.

[0064] Referring to FIG. 5, the actual value of the measured voltage and the filtered result value using an IIR filter (300) with a filter coefficient (A) of 32 can be examined. When comparing the actual measured value and the filtered result value, it is observed that the measured value remains at 2.5V (normal voltage) from cycle 1 to 15, then drops from cycle 15, drops to -2.5V at cycle 20, gradually recovers from cycle 29, and recovers to 2.5V (normal voltage) at cycle 35. On the other hand, the filtered correction value drops from cycle 19, so there may be a time delay of 4 cycles compared to the actual measured value. Also, starting from cycle 19, it can be seen that it only drops from 2.5V to 0.8V up to cycle 32. In other words, the difference between the normal voltage and the abnormal voltage is 5V (-2.5V to 2.5V) in the case of the actual measured value and 1.7V (0.8V to 2.5V) in the case of the filtered value, so it can be observed that the amount of voltage change is not sufficiently kept up. Finally, in the case of the actual measured value, it recovered to 2.5V (normal voltage) in 35 cycles, but in the case of the filtered value, it can be observed that the voltage, which dropped to 0.8V in 32 cycles, started to recover slowly and did not recover to 2.5V (normal voltage) over the entire measurement range of 1 to 45 cycles.

[0065] Detecting overvoltage with an IIR filter (300) as shown in Fig. 4 may be difficult to apply to a battery management system that needs to measure the voltage of a battery cell (110) at a period of 50ms to 200ms due to the delay time of the detection result.

[0066] FIG. 6 is a diagram illustrating an IIR filter with an added path for the input to bypass the filter when an overvoltage is detected according to various embodiments of the present invention, and FIG. 7 is a diagram illustrating the filtering result of the IIR filter with an added path for the input to bypass the filter when an overvoltage is detected, as proposed in FIG. 6.

[0067] The IIR filter (400) of Fig. 6 may be a filter that resolves the time delay in deriving the result value and the reduction in the amount of voltage change when using the IIR filter (300) of Fig. 4.

[0068] Referring to FIG. 6, the IIR filter (400) with an added overvoltage bypass path may have a circuit that calculates the difference (Vd) between the previous measurement and the current measurement and bypasses the filter to update the register with the current measurement when the measured value is greater than or equal to the threshold voltage (|Vx|).

[0069] Referring to FIG. 6, the IIR filter (400) with an added overvoltage bypass path can have a multiplexer (430) and a comparator (420) added to the IIR filter (410).

[0070] The multiplexer (430) can output the output of the IIR filter (410) as a result value when receiving a low (0) input through the selection input, and output the current measurement value (X[n]) when receiving a high (1) input.

[0071] The output of the comparator (420) is connected to the selection input of the multiplexer (430) so that the multiplexer (430) can select the input to be output based on the comparison result of the comparator (420).

[0072] The comparator (420) compares the difference between the current input value (X[n]) and the previous input value (X[n-1]), Vd (X[n] - X[n-1]), with the limit voltage (|Vx|). If the difference between the current input value and the previous input value (Vd) is greater than the limit voltage (|Vx|), it outputs a high (1) signal, and if it is smaller, it outputs a low (0) signal.

[0073] The comparator (420) can set the overvoltage determination criterion to when the difference (Vd) between the current input value and the previous input value is greater than the threshold voltage (|Vx|), and if the difference (Vd) is greater than the threshold voltage (|Vx|), it determines it as an overvoltage and outputs the current input value (X[n]), which is the high input of the multiplexer (430). At this time, the IIR filter (410) can be reset and updated starting from the current measurement value.

[0074] The comparator (420) can output a low output (0) when the difference (Vd) is less than the limit voltage (|Vx|) so that the IIR filter output value, which is the low input of the multiplexer (430), is output.

[0075] Accordingly, the IIR filter (400) with the added overvoltage bypass path shown in FIG. 6 of the present invention can immediately determine that there is an overvoltage when the difference between the current measurement value and the previous measurement value is large, and output the current measurement value as an output value without passing through the filter, thereby reducing the delay caused by time delay and allowing the amount of change in the measurement voltage to be output similarly to the actual value.

[0076] FIG. 7 illustrates the filtered result and the actual input measurement value after passing through the IIR filter (400) with the added overvoltage bypass path of FIG. 6, and it can be seen that the measurement value and the signal filtered by the IIR filter (400) with the added overvoltage bypass path match very closely. As a result, overvoltage due to voltage fluctuations can be quickly detected in battery cell monitoring while maintaining the magnitude of the voltage fluctuation.

[0077] FIG. 8 is a drawing showing a moving average filter (500), and FIG. 9 is a drawing showing the result of filtering an abnormal voltage through the moving average filter (500).

[0078] Referring to FIG. 8, the moving average filter (500) processes the input signal (X[n]) through four delay buffers (Z -1 By using ) to temporarily store and delay 5 input signals (X[n], X[n-1], X[n-2], X[n-3], X[n-4]), the average of these values ​​can be used to generate the final output signal. That is, Y[n] can be expressed as Y[n] = (X[n] + X[n-1] + X[n-2] + X[n-3] + X[n-4]) / 5.

[0079] Since the moving average filter (500) generates output values ​​with five values, time delay may inevitably occur, and the time delay may increase as the window of the input values ​​becomes larger. Therefore, it may be difficult to detect rapid changes in systems that require real-time processing. In addition, since data equal to the window size of the input values ​​cannot be used at the beginning and end of the data, accuracy may be reduced and distorted.

[0080] Referring to FIG. 9, when comparing the actual measured value with the result filtered using the moving average filter (500), it is observed that the actual measured value remains at 2.5V (normal voltage) from cycle 1 to cycle 15. An abnormal situation occurs at cycle 15, causing the voltage to drop sharply from 2.5V (normal voltage) to -2.5V at cycle 20, and then gradually recover from cycle 29 to 2.5V (normal voltage) at cycle 35. On the other hand, the result filtered using the moving average filter (500) begins to drop slowly from cycle 16, while the actual measured value drops sharply from cycle 15, which may result in a time delay of 1 cycle. Additionally, the filtered result can be seen to drop from cycle 16 to -2.5V at cycle 29. In other words, when comparing the time taken to reach -2.5 from 2.5V (normal voltage), the actual measured value is 20 cycles and the filtered result is 29 cycles, showing a time delay of 9 cycles. Finally, in the case of the actual measured value, it recovered to 2.5V (normal voltage) in 35 cycles, whereas in the case of the filtered value, it recovered slowly to 2.5 in 43 cycles, showing a delay of 8 cycles.

[0081] That is, detecting abnormal voltage with a moving average filter (500) may be difficult to apply in a battery management system that measures the voltage of a battery cell (110) at a period of 50ms to 200ms due to the delay in the time of detection of abnormal voltage caused by filtering.

[0082] FIG. 10 is a diagram illustrating a moving average filter with an additional path for the input to bypass the filter when an abnormal voltage is detected according to various embodiments of the present invention, and FIG. 11 is a diagram illustrating the filtered result of the moving average filter with an additional path for the input to bypass the filter when an abnormal voltage is detected, as proposed in FIG. 10.

[0083] The moving average filter (600) with the added bypass path of Fig. 10 may be designed to solve the time delay problem of the correction value caused by the filter correction that occurred in the moving average filter (500) of Fig. 8 described above.

[0084] Referring to FIG. 10, a moving average filter (600) with an added overvoltage bypass path can calculate (621) the difference (Vd) between a previous measurement and a current measurement, and compare (623) the difference (Vd) with a limit voltage (|Vx|). If the difference (Vd) is greater than the limit voltage (|Vx|), the moving average filter can be bypassed so that the current measurement is output as is, and if the difference (Vd) is less than the limit voltage (|Vx|), the result of the moving average filter can be output as output (Y).

[0085] Referring to FIG. 10, the moving average filter (600) with an added overvoltage bypass path can add a multiplexer (630) and a comparator (620) to the moving average filter (610).

[0086] The multiplexer (630) can output the output of the moving average filter (610) as the result value when receiving a low (0) input through the selection input, and output the current single measurement value (X[n]) when receiving a high (1) input.

[0087] The output of the comparator (620) is connected to the selection input of the multiplexer (630) so that the multiplexer (630) can select the input to be output based on the comparison result of the comparator (620).

[0088] The comparator (620) compares the difference between the current input value (X[n]) and the previous input value (X[n-1]), Vd (X[n] - X[n-1]), with the limit voltage (|Vx|). If the difference between the current input value and the previous input value (Vd) is greater than the limit voltage (|Vx|), it outputs a high (1) signal, and if it is smaller, it outputs a low (0) signal.

[0089] The comparator (620) sets the abnormal voltage determination criterion to when the difference (Vd) between the current input value and the previous input value is greater than the threshold voltage (|Vx|), and if the difference (Vd) is greater than the threshold voltage (|Vx|), it determines it as an abnormal voltage, and allows the multiplexer (630) to select the current input value (X[n]) as the output value without filter correction. Then, the moving average filter (610) is reset, and the delay buffer (Z) of the moving average filter (610) from the current measured voltage -1 It can be accumulated again in ).

[0090] The comparator (620) can output a low (0) when the difference (Vd) is less than the threshold voltage (|Vx|), thereby allowing the output value of the moving average filter (610), which is the low (0) side input of the multiplexer (630), to be output. At this time, when the result of the comparator (623) changes from high (1) to low (0), the comparator (620) does not immediately transmit the low (0) to the selection input of the multiplexer (630), but rather uses the delay buffer (Z) provided by the moving average filter (610). -1 After delaying (625) by the number of ) values, it can be passed to the selection input of the multiplexer (630). This is the delay buffer (Z) of the moving average filter (610). -1 This is to wait for the time when all input values ​​are updated. This is because if this delay is not introduced, the output value of the moving average filter (610) is output immediately from the current value output, and the values ​​prior to the current value are reflected, resulting in an incorrect output.

[0091] Accordingly, the comparator (620) immediately transmits the output value to the multiplexer (630) when the output value changes from low to high, and when the output value changes from high to low, the delay buffer (Z) provided by the moving average filter (610) -1 After delaying (625) by the number of ) values, it can be transmitted to the multiplexer (630). According to one embodiment, it changes from high to low and then the delay buffer (Z) equipped with the moving average filter (610) changes from high to low. -1If the output changes back from low to high before the number of cycles proceeds, the low output is not transmitted to the multiplexer (630) and the high output can continue to be transmitted to the multiplexer (630).

[0092] Accordingly, the moving average filter (600) with the added abnormal voltage bypass path shown in FIG. 10 can immediately determine that there is an abnormal operation when the difference between the current measurement value and the previous measurement value is large, and output the current measurement value as the result value without passing through the filter, thereby reducing the delay caused by time delay.

[0093] Referring to FIG. 11, the result value filtered by the moving average filter (600) with the added abnormal voltage bypass path of FIG. 10 and the actual measured value are shown, and it can be seen that the measured value and the result value filtered by the moving average filter (600) with the added abnormal voltage bypass path match very closely. As a result, abnormal operation during voltage fluctuation in battery cell monitoring can be quickly detected while maintaining the magnitude of the voltage fluctuation.

[0094] The moving average filter (600) with the added overvoltage bypass path of FIG. 10 described above is designed to take a moving average of five consecutive cycles by having four delay buffers, but the number of delay buffers provided by the moving average filter (600) can be increased or decreased depending on the specifications or conditions of the system.

[0095] The IIR filter and moving average filter with the added overvoltage bypass path of FIGS. 6 to 10 of the present invention described above can detect abnormal operation by rapidly determining the overvoltage, and thus can be applied to all systems that require monitoring the battery at short intervals. For example, it can be applied to battery systems such as electric vehicles and hydrogen vehicles that have built-in batteries.

[0096] In addition, the threshold voltage (Vx) for determining overvoltage may vary depending on the system or usage situation, as the noise level varies depending on the system or usage situation.

[0097] As described above, the present invention has been explained by limited embodiments and drawings, but the present invention is not limited to the above embodiments and modifications or variations of the described matters are possible. Therefore, the scope of the invention is not limited to the described embodiments but should be defined by the claims set forth below as well as equivalents thereof.

[0098] Those skilled in the art related to the embodiments described above will understand that they may be implemented in modified forms without departing from the essential characteristics of the description. Therefore, the disclosed methods should be considered in an illustrative rather than a limiting sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalence should be interpreted as being included in the invention. Explanation of the symbols

[0100] 100: Battery module 110: Battery cell 200: BMIC (Battery Monitor Integrated Circuit) 210: Monitoring Department 220: Operation unit 230: Communications Department 300: IIR (Infinite Impulse Response) Filter 310: Subtractor 320: Comparator 330: Adder 400: IIR filter with added overvoltage bypass path 410: IIR filter 420: Comparator 430: Multiplexer 500: Moving Average Filter 600: Moving average filter with added overvoltage bypass path 610: Moving Average Filter 620: Comparator 621: Subtractor 623: Comparator 625: Delay buffer 630: Multiplexer

Claims

Claim 1 A battery management system for detecting overvoltage, comprising: an Infinite Impulse Response (IIR) filter that determines the current output voltage by adding a value obtained by multiplying the difference between the current input voltage and the output voltage one cycle prior by a filter coefficient to the output voltage one cycle prior; a comparator that outputs a result of comparing the difference between the current input voltage and the input voltage one cycle prior with a limit voltage; and a multiplexer that selects and outputs one of the current output voltage of the IIR filter and the current input voltage according to the output result of the comparator. Claim 2 A battery management system according to claim 1, wherein the comparator outputs a first value when the difference between the input voltage one cycle prior and the current measured voltage is greater than the limit voltage, and outputs a second value different from the first value when the difference between the input voltage one cycle prior and the current measured voltage is less than the limit voltage, and the multiplexer selects and outputs the current input voltage when the first value is received as a selection input, and selects and outputs the output voltage of the IIR filter when the second value is received as a selection input. Claim 3 A battery management system according to claim 1 or 2, wherein the comparator outputs the first value immediately when the output value changes from the second value to the first value, and outputs the second value with a one-cycle delay when the output value changes from the first value to the second value. Claim 4 A battery management system comprising: a moving average filter that averages and outputs input voltages input over a plurality of consecutive cycles; a comparator that outputs a result of comparing the difference between an input voltage one cycle prior and a current input voltage with a limit voltage; and a multiplexer that selects and outputs one of the output voltage of the moving average filter and the current input voltage according to the output result of the comparator. Claim 5 A battery management system according to claim 4, wherein the comparator outputs a first value when the difference between the input voltage one cycle prior and the current measured voltage is greater than the limit voltage, and outputs a second value different from the first value when the difference between the input voltage one cycle prior and the current measured voltage is less than the limit voltage, and the multiplexer selects and outputs the current input voltage when the first value is received as a selection input, and selects and outputs the output voltage of the moving average filter when the second value is received as a selection input. Claim 6 A battery management system according to claim 4, wherein the moving average filter is configured such that a plurality of delay buffers are connected in a sequence, and in every cycle, the first delay buffer among the plurality of delay buffers receives and stores the current input voltage, the remaining delay buffers among the plurality of delay buffers, excluding the first delay buffer, receive and store the value stored in the preceding delay buffer, and calculate and output the average of the value stored in the plurality of delay buffers and the current input voltage. Claim 7 A battery management system according to claim 5 or 6, wherein the comparator outputs the first value immediately when the output value changes from the second value to the first value, and outputs the second value after delaying it by the number of cycles of the plurality of delay buffers when the output value changes from the first value to the second value. Claim 8 A battery management system according to claim 7, wherein the comparator, while delaying the output of the second value as the output value changes from the second value to the first value, does not execute the output of the second value and maintains the output of the first value. Claim 9 A method for detecting an abnormal voltage in a battery management system, comprising: a step of determining the current output voltage of an IIR (Infinite Impulse Response) filter by adding a value obtained by multiplying the difference between the current input voltage and the output voltage one cycle prior by a filter coefficient to the output voltage one cycle prior; a step of outputting a result of comparing the difference between the current input voltage and the input voltage one cycle prior with a limit voltage; and a step of selecting and outputting one of the current output voltage of the IIR filter and the current input voltage according to the result of the comparison. Claim 10 In claim 9, the step of outputting the result of comparing the difference between the current input voltage and the input voltage from one cycle prior with the limit voltage is to output a first value when the difference between the input voltage from one cycle prior and the current measured voltage is greater than the limit voltage, and to output a second value different from the first value when the difference between the input voltage from one cycle prior and the current measured voltage is less than the limit voltage, and the step of selecting and outputting one of the current output voltage of the IIR filter and the current input voltage according to the result of the comparison is to select and output the current input voltage when the first value is received as a selection input, and to select and output the output voltage of the IIR filter when the second value is received as a selection input. Claim 11 An overvoltage detection method according to claim 9 or 10, wherein the step of outputting the result of comparing the difference between the current input voltage and the input voltage one cycle prior with the limit voltage is to output the first value immediately when the output value changes from the second value to the first value, and output the second value with a one-cycle delay when the output value changes from the first value to the second value. Claim 12 An abnormal voltage detection method comprising: a step of determining the current output voltage of a moving average filter that averages input voltages input over a plurality of consecutive cycles; a step of determining the result of comparing the difference between the input voltage one cycle prior and the current input voltage with a limit voltage as the output voltage; and a step of selecting and outputting one of the output voltage of the moving average filter and the current input voltage according to the result of the step of determining the comparison result as the output voltage. Claim 13 In claim 12, the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage is to output a first value when the difference between the input voltage one cycle prior and the current measured voltage is greater than the limit voltage, and to output a second value different from the first value when the difference between the input voltage one cycle prior and the current measured voltage is less than the limit voltage, and the step of selecting and outputting one of the output voltage of the moving average filter and the current input voltage according to the output result of the comparator is to select and output the current input voltage when the first value is received as the selection input, and to select and output the output voltage of the moving average filter when the second value is received as the selection input. Claim 14 In claim 12, a step of determining the current output voltage of a moving average filter that averages and outputs input voltages input in a plurality of consecutive cycles; a plurality of delay buffers are configured to be connected in a sequence, and for each cycle, the first delay buffer among the plurality of delay buffers receives and stores the current input voltage, and the remaining delay buffers among the plurality of delay buffers, excluding the first delay buffer, receive and store the value stored in the preceding delay buffer, and calculate and output the average of the value stored in the plurality of delay buffers and the current input voltage. Claim 15 A method for detecting abnormal voltage according to claim 13 or 14, wherein the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage is to output the first value immediately when the output value changes from the second value to the first value, and output the second value after delaying it by the number of cycles of the plurality of delay buffers when the output value changes from the first value to the second value. Claim 16 In claim 15, the step of determining the output voltage by comparing the difference between the input voltage one cycle prior and the current input voltage with the limit voltage is an overvoltage detection method in which, when the output value changes from the second value to the first value while delaying the output of the second value as the output value changes from the first value to the second value, the output of the second value is not executed and the output of the first value is maintained as is.

Images