Current detection device and method

Abstract

The invention discloses a current detection device and method, and relates to the technical field of battery management. The current detection device comprises a shunt, a signal adjustment and detection system, a short-circuit protection system and a control module, the shunt is electrically connected with the battery management system and is used for detecting a first voltage signal of the battery management system; the signal adjusting and detecting system is electrically connected with the diverter and the control module, and the signal adjusting and detecting system is used for determining a target voltage signal according to the first voltage signal and a preset modulation locking amplification strategy; the short-circuit protection system is electrically connected with the diverter and the control module and is used for monitoring the first voltage signal and outputting a trigger signal to the control module under the condition that the first voltage signal does not meet a preset protection condition; the control module is used for determining the current abnormal condition of the battery management system according to the target voltage signal and the trigger signal. According to the invention, the dual requirements of high-precision measurement and rapid protection can be met.

Description

Technical Field

[0001] This application relates to the field of battery management technology, specifically to current detection devices and methods. Background Technology

[0002] In a battery management system (BMS), high-precision current sensing technology is a key foundation for achieving safe battery operation and accurate state estimation. Traditional current sensing schemes mainly employ a direct measurement method using a shunt combined with an instrumentation amplifier. While this method is simple in structure, it faces significant technical challenges in practical applications.

[0003] Traditional current sensing schemes directly amplify and sample the voltage signal output by the shunt, exposing the system to complex noise environments. Especially in high-reliability applications such as new energy vehicles, these methods still struggle to meet the dual requirements of high-precision measurement and rapid protection. Summary of the Invention

[0004] Purpose of the invention: The embodiments of this application provide a current detection device and method to meet the dual requirements of high-precision measurement and rapid protection of current detection in battery management systems.

[0005] Technical solution: The current detection device described in this application includes: a shunt, a signal conditioning and detection system, a short-circuit protection system, and a control module; wherein, the shunt is electrically connected to the battery management system and is used to detect the first voltage signal of the battery management system;

[0006] The signal conditioning and detection system is electrically connected to the shunt and the control module respectively. The signal conditioning and detection system is used to determine the target voltage signal based on the first voltage signal and the preset modulation lock-in amplification strategy.

[0007] The short-circuit protection system is electrically connected to the shunt and the control module respectively. It is used to monitor the first voltage signal and output a trigger signal to the control module when the first voltage signal does not meet the preset protection conditions.

[0008] The control module is used to determine abnormal current conditions in the battery management system based on the target voltage signal and the trigger signal.

[0009] In some embodiments, the signal conditioning and detection system includes a signal modulation module and a lock-in amplification module;

[0010] The signal modulation module is electrically connected to the shunt and the lock-in amplifier module respectively. The signal modulation module is used to modulate the first voltage signal into a high-frequency carrier modulation signal.

[0011] The locking amplifier module is electrically connected to the control module. The locking amplifier module is used to extract the target voltage signal from the high-frequency carrier modulation signal.

[0012] In some embodiments, the signal modulation module includes: an amplification unit, a first signal generation unit, a first analog multiplication unit, and a first filtering unit; wherein, the amplification unit is used to amplify the first voltage signal by a preset factor to obtain a second voltage signal;

[0013] The first signal generating unit is used to generate a carrier signal;

[0014] The first analog multiplication unit is used to amplitude modulate the second voltage signal and the carrier signal to obtain the third voltage signal;

[0015] The first filtering unit is used to reduce the noise of the third voltage signal to obtain a high-frequency carrier modulated signal.

[0016] In some embodiments, the locking amplification module includes: a second signal generation unit, a second analog multiplication unit, and a second filtering unit; the second signal generation unit is used to generate a reference signal; the second analog multiplication unit is used to multiply the reference signal and the high-frequency carrier modulation signal to obtain a baseband demodulated signal; and the second filtering unit is used to filter out noise from the baseband demodulated signal to obtain a target voltage signal.

[0017] In some embodiments, the current detection device further includes a temperature compensation module; the temperature compensation module is electrically connected to the shunt, the amplification unit and the control module respectively, and is used to obtain the current temperature of the shunt, determine the target gain according to the current temperature and the preset temperature drift compensation strategy, and adjust the preset multiple according to the target gain.

[0018] In some embodiments, the temperature compensation module includes: a distributed temperature detection unit, a thermal gradient compensation circuit, and a gain adjustment unit; wherein, the distributed temperature detection unit is disposed in the critical heat-sensitive area of ​​the shunt and is used to detect the current temperature of the critical heat-sensitive area;

[0019] The thermal gradient compensation circuit is electrically connected to the distributed temperature detection unit to obtain the current temperature and historical temperature of the heat-sensitive area. It divides the temperature range into multiple temperature ranges based on the historical temperature and determines the shunt coefficient deviation corresponding to each temperature range based on the current temperature and a preset piecewise polynomial fitting algorithm.

[0020] The gain adjustment unit is used to determine the target gain based on the preset reference gain, the preset temperature drift compensation coefficient, and the shunt coefficient deviation corresponding to each temperature range, and adjust the preset multiple according to the target gain.

[0021] In some embodiments, the short-circuit protection system includes a comparison module, which is used to compare a first voltage signal with a preset voltage threshold, and output a trigger signal to the control module when the first voltage signal exceeds the preset voltage threshold.

[0022] In some embodiments, the short-circuit protection system further includes an optocoupler isolation module, which is electrically connected to the comparison module and the control module respectively, and is used to isolate and reduce noise from the trigger signal.

[0023] In some embodiments, the control module is further configured to: determine a target current signal based on the target voltage signal and the resistance of the shunt;

[0024] And if the target current signal exceeds the preset current threshold, and / or, upon receiving a trigger signal, determine that the battery management system has a current anomaly.

[0025] Accordingly, this application also provides a current detection method, including:

[0026] Detect the first voltage signal of the battery management system;

[0027] The target voltage signal is determined based on the first voltage signal and a preset modulation lock-in amplification strategy;

[0028] Monitor the first voltage signal, and output a trigger signal if the first voltage signal does not meet the preset protection conditions;

[0029] The abnormal current condition of the battery management system is determined based on the target voltage signal and the trigger signal.

[0030] Beneficial Effects: Compared with the prior art, the current detection device and method of this application include: a shunt, a signal adjustment and detection system, a short-circuit protection system, and a control module; wherein, the shunt is electrically connected to the battery management system and is used to detect the first voltage signal of the battery management system; the signal adjustment and detection system is electrically connected to the shunt and the control module respectively, and is used to determine the target voltage signal according to the first voltage signal and a preset modulation lock-in amplification strategy; the short-circuit protection system is electrically connected to the shunt and the control module respectively, and is used to monitor the first voltage signal, and output a trigger signal to the control module when the first voltage signal does not meet the preset protection conditions; the control module is used to determine the current abnormality of the battery management system according to the target voltage signal and the trigger signal. The current detection device provided by this application fundamentally solves the noise interference problem by setting up a dual-path parallel processing architecture of the signal adjustment and detection system and the short-circuit protection system, thereby improving the detection accuracy, and realizing short-circuit protection through the short-circuit protection system. This decouples the high-precision current detection and fast protection functions, resolves the contradiction between protection speed and measurement accuracy, and meets the dual requirements of high-precision measurement and fast protection. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the principle structure of a current detection device provided in the embodiments of this application;

[0033] Figure 2 This is a schematic diagram of another current detection device provided in the embodiments of this application;

[0034] Figure 3 This is a locking amplification timing diagram provided in the embodiments of this application;

[0035] Figure 4 This is a flowchart of a temperature compensation algorithm provided in an embodiment of this application;

[0036] Figure 5 This is a schematic diagram of the structure of a non-inverting proportional operational circuit provided in the embodiments of this application;

[0037] Figure 6 This is an overall architecture diagram of a current detection device provided in the embodiments of this application;

[0038] Figure 7This is a flowchart of a current detection method provided in the embodiments of this application.

[0039] Figure label:

[0040] 10-Battery Management System; 20-Shunter; 30-Control Module; 100-Signal Adjustment and Detection System; 110-Signal Modulation Module; 111-Amplification Unit; 112-First Signal Generation Unit; 113-First Analog Multiplication Unit; 114-First Filtering Unit; 120-Lock-in Amplification Module; 121-Second Signal Generation Unit; 122-Second Analog Multiplication Unit; 123-Second Filtering Unit; 200-Short Circuit Protection System; 210-Comparison Module; 220-Optical Isolation Module; 300-Temperature Compensation Module; 310-Distributed Temperature Detection Unit; 320-Thermal Gradient Compensation Circuit; 330-Gain Adjustment Unit. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0042] It should be understood that although the terms first, second, etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component discussed below may be referred to as the second component without departing from the teachings of this application. As used herein, the term "and / or" includes all combinations of any and more of the associated listed items.

[0043] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments and may not be to scale. The modules or processes shown in the drawings are not necessarily essential for implementing this application and therefore should not be used to limit the scope of protection of this application.

[0044] The applicant's research revealed that high-precision current sensing technology is a crucial foundation for achieving safe battery operation and accurate state estimation in battery management systems. Traditional current sensing schemes primarily employ a direct measurement method combining a shunt and an instrumentation amplifier. While this method is structurally simple, it faces significant technical challenges in practical applications.

[0045] First, traditional solutions perform poorly in suppressing electromagnetic interference. The BMS operating environment contains a significant amount of high-frequency switching noise, including noise generated by power metal-oxide-semiconductor field-effect transistor (MOSFET) switches and electromagnetic radiation interference. These interference signals directly couple into the microvolt-level current sensing signal, resulting in a severe deterioration of the signal-to-noise ratio.

[0046] Secondly, there is the issue of temperature drift compensation. Commonly used copper shunts operate over a wide temperature range of -40℃ to 85℃, resulting in significant resistance variations. Traditional single-point calibration and linear compensation methods struggle to accurately match the shunt's nonlinear temperature characteristic curve, especially under conditions of sudden temperature changes, leading to substantial compensation errors. Furthermore, the temperature gradient effect present in the shunt further complicates the compensation process.

[0047] In terms of system protection, traditional architectures present a trade-off between speed and accuracy. On the one hand, battery systems require short-circuit protection to be completed in a short time, while software-based processing paths suffer from delays due to signal chains. On the other hand, while simple hardware comparator solutions offer fast responses, they lack temperature compensation mechanisms, leading to a significant increase in false trigger rates under extreme temperature conditions.

[0048] For example, patent application CN202010920530.3 discloses a current detection circuit, a current detection system, and a method for adjusting the current detection circuit. The embodiments of this invention relate to a current detection circuit, a current detection system, and a method for adjusting the current detection circuit. The current detection circuit in this embodiment includes: a current detection unit that has an operational amplifier that compares a first voltage proportional to the load current and a second voltage proportional to the detected current, and outputs a detected current; and an adjustment unit that generates data corresponding to the result of comparing a monitoring voltage proportional to the detected current and a reference voltage, and adjusts the input bias of the operational amplifier.

[0049] For example, patent application CN201621164329.2 discloses a lock-in amplifier. This lock-in amplifier includes a first resistor divider network, a second resistor divider network, an adder, a bandpass filter, a phase-sensitive detector, a low-pass filter, a phase shifter, and a sampling and display circuit. Interference signals enter the lock-in amplifier through the first resistor divider network. The reference signal is split into two paths: one path enters through the second resistor divider network, and the other path enters the phase shifter. The output of the phase shifter is connected to the phase-sensitive detector. This lock-in amplifier effectively detects weak signal amplitudes in strong noise environments. The research focuses on phase-sensitive detection technology in weak signal detection methods, involving the superposition, attenuation, filtering, and detection of the amplified noise source and sinusoidal interference signal, followed by AD sampling processing and display, forming a complete lock-in amplification system.

[0050] For example, patent application CN201010527363.2 discloses a current detection device, a current detection signal comparison device, a current detection method, and a current detection signal comparison method. It includes a current detection circuit for detecting a current signal of a switching circuit to generate a current detection signal; a control circuit for outputting a control signal; and a compensation circuit for compensating the current detection signal according to the control signal. The compensated current detection signal is compared with a constant current reference signal to output a constant current control signal. Furthermore, another aspect of the present invention configures the compensation circuit to compensate for a constant current reference signal and compares the current detection signal with the compensated constant current reference signal to output a constant current control signal.

[0051] However, traditional current sampling schemes directly amplify and sample the voltage signal output by the shunt, exposing the system to complex noise environments. Traditional temperature compensation uses fixed coefficients, resulting in significant errors. In high-reliability applications such as new energy vehicles, these methods still fall short of meeting the requirements for accurate measurement. Therefore, it is necessary to develop a current sensing technology that can simultaneously address high-frequency noise suppression, wide-temperature-range nonlinear compensation, and rapid protection optimization.

[0052] In view of this, embodiments of this application provide a current detection device and method. This application sets up a dual-path parallel processing architecture of a signal adjustment and detection system and a short-circuit protection system, and uses a preset modulation lock-in amplification strategy to fundamentally solve the noise interference problem, thereby improving the detection accuracy. Short-circuit protection is achieved through the short-circuit protection system, thereby decoupling the functions of high-precision current detection and fast protection, resolving the contradiction between protection speed and measurement accuracy, and meeting the dual requirements of high-precision measurement and fast protection.

[0053] Figure 1This is a schematic block diagram of a current detection device provided in an embodiment of this application. Please refer to... Figure 1 The current detection device of the battery management system 10 includes: a shunt 20, a signal adjustment and detection system 100, a short-circuit protection system 200, and a control module 30. The shunt 20 is electrically connected to the battery management system 10 and is used to detect a first voltage signal of the battery management system 10. The signal adjustment and detection system 100 is electrically connected to the shunt 20 and the control module 30, respectively, and is used to determine a target voltage signal based on the first voltage signal and a preset modulation lock-in amplification strategy. The short-circuit protection system 200 is electrically connected to the shunt and the control module 30, respectively, and is used to monitor the first voltage signal. If the first voltage signal does not meet the preset protection conditions, it outputs a trigger signal to the control module 30. The control module 30 is used to determine the abnormal current condition of the battery management system 10 based on the target voltage signal and the trigger signal.

[0054] For example, shunt 20 can be selected as a shunt with a resistance of 0.05mΩ. The specific value can be set according to the actual situation, and no specific limitation is made here.

[0055] The first voltage signal is a DC / low-frequency small (e.g., μV to mV level) voltage signal (containing noise).

[0056] Among them, the preset modulation lock-in amplification strategy adopts an innovative architecture that combines signal modulation and lock-in amplification. It shifts the weak current signal to a high-frequency carrier and then performs synchronous demodulation, which fundamentally solves the problem of high-frequency noise interference and thus improves the accuracy of current detection.

[0057] When the first voltage signal meets the preset protection conditions, the short-circuit protection system 200 outputs a trigger signal to the control module 30. The preset protection conditions include comparing the first voltage signal with a preset short-circuit protection voltage threshold. For example, if the first voltage signal exceeds the preset short-circuit protection voltage threshold, a trigger signal is output to the control module 30, indicating an abnormal current and a possible short circuit in the battery management system 10. Otherwise, no trigger signal is output. The specific value of the preset short-circuit protection voltage threshold can be set according to actual conditions and is not specifically limited here.

[0058] The trigger signal can be either a high-level signal or a low-level signal, and the specific setting can be determined according to the actual situation. No specific limitation is made here.

[0059] The control module 30 can be a microcontroller, such as an STM32 microcontroller or other control chip. The specific configuration can be set according to the actual situation, and no specific limitations are made here.

[0060] In the technical solution of this application embodiment, the implementation process of the current detection device is as follows: For example, please refer to... Figure 1 The battery management system 10 is electrically connected to the shunt 20, which is in turn electrically connected to the signal conditioning and detection system 100 and the short-circuit protection system 200. Both the signal conditioning and detection system 100 and the short-circuit protection system 200 are electrically connected to the control module 30. First, the shunt 20 detects and obtains the first voltage signal of the battery management system 10. Then, the signal conditioning and detection system 100 uses an innovative architecture combining signal modulation and lock-in amplification to modulate the first voltage signal onto a specific high-frequency carrier, shifting the signal spectrum to a less noisy frequency band. Lock-in amplification technology is then used for synchronous demodulation to obtain the target voltage signal, fundamentally solving the high-frequency noise interference problem and improving current detection accuracy. Furthermore, the short-circuit protection system 200 monitors the first voltage signal, and if the first voltage signal does not meet preset protection conditions, such as exceeding a preset short-circuit protection voltage threshold, it outputs a trigger signal to the control module 30 to monitor short-circuit risk. The control module 30 determines whether the current of the battery management system 10 is abnormal based on the received target voltage signal and trigger signal. Therefore, this application fundamentally solves the noise interference problem by setting up a dual-path parallel processing architecture of signal adjustment and detection system and short-circuit protection system, and by using a preset modulation lock-in amplification strategy to improve detection accuracy. Short-circuit protection is achieved through the short-circuit protection system, thereby decoupling the functions of high-precision current detection and fast protection, resolving the contradiction between protection speed and measurement accuracy, and meeting the dual requirements of high-precision measurement and fast protection.

[0061] Figure 2 This is a schematic block diagram of another current detection device provided in the embodiments of this application. Based on the above embodiments, please refer to... Figure 2 The signal adjustment and detection system 100 includes a signal modulation module 110 and a lock-in amplification module 120. The signal modulation module 110 is electrically connected to the shunt 20 and the lock-in amplification module 120 respectively. The signal modulation module 110 is used to modulate the first voltage signal into a high-frequency carrier modulation signal. The lock-in amplification module 120 is electrically connected to the control module 30. The lock-in amplification module 120 is used to extract the target voltage signal from the high-frequency carrier modulation signal.

[0062] The input signal to the signal modulation module 110 is a μV to mV level DC / low-frequency voltage signal (including noise) output from the shunt 20, i.e., the first voltage signal. The principle and function of the signal modulation module 110 are as follows: A high-frequency carrier wave (e.g., a 50kHz sine wave) is used to amplitude modulate the initially amplified input signal (i.e., the initially amplified first voltage signal) through an analog multiplier. This shifts the spectrum of the low-frequency current signal to near the carrier frequency, and after bandpass filtering and noise reduction, the signal is output, avoiding low-frequency 1 / f noise and power frequency interference, improving the signal-to-noise ratio, and creating conditions for subsequent lock-in amplification. The output signal of the signal modulation module 110 is a modulated AC signal (whose amplitude is proportional to the first voltage signal of the shunt 20, and whose frequency is synchronized with the carrier signal), i.e., a high-frequency carrier modulated signal.

[0063] Lock-in amplifier is a precision measurement technique used to extract weak signals. Its core principle is to recover a target signal of a specific frequency from a strong noise background through synchronous demodulation.

[0064] The input signal to the lock-in amplifier module 120 is the high-frequency modulated signal (including noise) output by the signal modulation module 110, i.e., the high-frequency carrier modulation signal. The principle and function of the lock-in amplifier module 120 are as follows: by multiplying with a reference signal in phase with the carrier signal, the high-frequency carrier modulation signal is shifted back to the fundamental frequency, thus suppressing noise due to phase randomness. A low-pass filter removes high-frequency noise and demodulated harmonic components, retaining the DC component (i.e., the original current signal), thereby extracting weak effective signals and suppressing asynchronous noise, achieving high-precision current measurement. The output signal of the lock-in amplifier module 120 is the demodulated DC voltage (corresponding to the current value), i.e., the target voltage signal, which is sampled by an analog-to-digital converter (ADC) and then sent to the subsequent control module 30.

[0065] It should be noted that the lock-in amplifier module 120 can also utilize a digital quadrature demodulation scheme, performing signal processing in the digital domain after sampling by an ADC. The specific implementation principle and process of the digital quadrature demodulation scheme are as follows: The traditional analog lock-in amplifier circuit is replaced by ADC sampling and digital signal processing technology. This scheme first uses an ADC to digitize the input signal, with the sampling rate typically needing to be at least four times the signal frequency to satisfy the Nyquist sampling theorem. The sampled digital signal is then mixed and multiplied with two orthogonal digital reference signals (sine and cosine), a process that achieves synchronous signal detection in the digital domain. The mixed signal is then processed by a digital low-pass filter to remove high-frequency components, resulting in a DC component containing amplitude and phase information. Finally, the signal amplitude is extracted by calculating the square root of the sum of the squares of these two orthogonal components, and the phase difference is calculated using the arctangent function.

[0066] In some embodiments, please continue reading Figure 2 The short-circuit protection system 200 includes a comparison module 210, which compares a first voltage signal with a preset voltage threshold and outputs a trigger signal to the control module 30 when the first voltage signal exceeds the preset voltage threshold.

[0067] Among them, the comparison module 210 is a hardware comparator, such as a high-speed comparator.

[0068] It should be noted that the high-speed comparator in the short-circuit protection system can use an ADC and a Field-Programmable Gate Array (FPGA) to implement programmable threshold protection. Specifically, the implementation principle and process of programmable threshold protection using an ADC and FPGA are as follows: The current signal is sampled in real time using a high-speed ADC. The selection of the ADC needs to consider the sampling rate and resolution, typically requiring a sampling rate of at least 1 MSPS and a resolution of at least 12 bits to ensure accurate capture of rapid current changes. The sampled digital signal is sent to the FPGA for processing. The FPGA has a programmable threshold register that can store multiple levels of protection thresholds, such as warning values ​​and shutdown values. The FPGA uses parallel comparison logic to compare the ADC sampled data with the preset threshold in real time every clock cycle. When the current exceeds the threshold, the protection mechanism is immediately triggered. To improve the system's anti-interference capability, the FPGA also performs digital filtering on the sampled data, such as using a moving average filtering algorithm to suppress transient noise interference. Simultaneously, pulse counting protection logic is set up; protection is only triggered when the current continuously exceeds the limit for a preset number of cycles, thus effectively avoiding false triggering.

[0069] The protection logic output of the FPGA can directly drive optocouplers or power switching devices to achieve fast shutdown. Its response time can be controlled within 500 nanoseconds. The protection threshold can also be dynamically adjusted through the host computer communication interface, and the protection parameters can be flexibly configured according to the actual working conditions.

[0070] The specific value of the preset voltage threshold can be set according to the actual situation, and no specific limit is made here.

[0071] It is understood that this application adopts a unique dual-path parallel processing architecture, namely, a signal adjustment and detection system 100 and a short-circuit protection system 200. The signal adjustment and detection system 100 is a high-precision monitoring path. Specifically, the signal modulation module 110 modulates the μV to mV level micro-voltage signal output from the shunt 20 onto a specific high-frequency carrier (i.e., a high-frequency carrier modulation signal), shifting the spectrum of the high-frequency carrier modulation signal to a less noisy frequency band. Then, through the lock-in amplification module 120, synchronous demodulation technology, combined with low-pass filtering, accurately extracts the target voltage signal from the modulated signal, effectively suppressing noise interference and improving current detection accuracy. The short-circuit protection system 200 is a fast protection path. An independent hardware comparator directly monitors the first voltage signal of the shunt 20, achieving μs-level short-circuit protection. Thus, through this dual-path parallel processing architecture, high-precision detection and fast protection functions are decoupled. The coordinated operation of the hardware comparator and the software algorithm (i.e., the preset modulation lock-in amplification strategy) resolves the contradiction between protection speed and measurement accuracy, meeting the dual requirements of high-precision measurement and fast protection for current detection in the battery management system.

[0072] In some embodiments, please continue reading Figure 2 The short-circuit protection system 200 also includes an optocoupler isolation module 220, which is electrically connected to the comparison module 210 and the control module 30 respectively, and is used to isolate and reduce noise of the trigger signal.

[0073] The optical isolation module 220 can be a high-speed optical coupler or a general-purpose optical coupler, and the specific configuration can be made according to the actual situation. No specific limitations are made here.

[0074] In some embodiments, please continue reading Figure 2 The signal modulation module 110 includes: an amplification unit 111, a first signal generation unit 112, a first analog multiplication unit 113, and a first filtering unit 114; wherein, the amplification unit 111 is used to amplify the first voltage signal by a preset factor to obtain a second voltage signal; the first signal generation unit 112 is used to generate a carrier signal; the first analog multiplication unit 113 is used to perform amplitude modulation on the second voltage signal and the carrier signal to obtain a third voltage signal; and the first filtering unit 114 is used to perform noise reduction processing on the third voltage signal to obtain a high-frequency carrier modulation signal.

[0075] The amplification unit 111 is an instrumentation amplifier. For example, the initial gain G of the instrumentation amplifier is 100. The gain of the instrumentation amplifier can be adjusted in real time according to temperature compensation to ensure the amplification factor of the first voltage signal is reasonable, thereby improving the accuracy of subsequent current detection.

[0076] The first signal generating unit 112 is a carrier generator used to generate a carrier signal. The carrier signal is a high-frequency carrier signal, such as a 50Hz sinusoidal carrier signal.

[0077] The first analog multiplication unit 113 is an analog multiplier used to multiply the first voltage signal (i.e. the second voltage signal) after being amplified by a preset factor with the carrier signal to perform amplitude modulation to obtain the third voltage signal.

[0078] The first filtering unit 114 is a bandpass filter, and its center frequency is the same as the frequency of the carrier signal.

[0079] In some embodiments, please continue reading Figure 2 The locked amplification module 120 includes: a second signal generation unit 121, a second analog multiplication unit 122, and a second filtering unit 123; the second signal generation unit 121 is used to generate a reference signal; the second analog multiplication unit 122 is used to multiply the reference signal and the high-frequency carrier modulation signal to obtain a baseband demodulated signal; the second filtering unit 123 is used to filter out noise from the baseband demodulated signal to obtain the target voltage signal.

[0080] The second signal generating unit 121 is a signal generator used to generate a reference signal. The reference signal is in phase and frequency with the carrier signal.

[0081] The second analog multiplication unit 122 is an analog multiplier used to multiply the reference signal with the high-frequency carrier modulation signal to obtain the baseband demodulated signal.

[0082] The second filtering unit 123 is a low-pass filter. For example, the cutoff frequency of the low-pass filter is 100Hz.

[0083] Figure 3 This is a locking amplification timing diagram provided in an embodiment of this application. For an example, please refer to... Figure 3 The principle of locking amplified detection of shunt current is as follows: the signal modulation module 110 multiplies the small voltage signal (containing noise) detected by the shunt 20 with the carrier signal, shifting the current signal spectrum to near the carrier frequency to avoid low-frequency noise (such as 1 / f noise). The specific process is as follows:

[0084] First, current input: The original signal (i.e., the first voltage signal) from the shunt 20 is amplified by the instrumentation amplifier to obtain the second voltage signal V(t):

[0085] V(t) = I(t) × R + N(t);

[0086] Where I(t) represents the current signal to be measured (which may contain a DC component I0 and an AC component i(t)); R represents the resistance value of the shunt 20 (which is precisely known); and N(t) represents the noise signal (which includes 1 / f noise, thermal noise, etc.).

[0087] Second, the carrier signal C(t) is:

[0088]

[0089] Where w0 represents the carrier angular frequency, w0 = 2πf0; A represents the initial phase; A_m represents the modulation amplitude, which is usually normalized to 1.

[0090] Third, the high-frequency carrier modulated signal is equal to the signal obtained by multiplying the second voltage by the carrier signal and then reducing noise through a bandpass filter. The formula for calculating the high-frequency carrier modulated signal V_mod(t) is:

[0091]

[0092] Fourth, the synchronous demodulation module (including the second signal generation unit 121 and the second analog multiplication unit 122) is used to multiply with the reference signal to restore the target signal (i.e., the high-frequency carrier modulation signal) to the fundamental frequency demodulated signal, thereby significantly suppressing noise due to phase randomness. The reference signal D(t) is:

[0093]

[0094] Where A_d represents the demodulation amplitude, which is usually normalized to 1; This represents the initial phase of the reference signal. The fundamental frequency demodulated signal V_demod(t) is:

[0095] V_demod(t)=V_mod(t)·D(t);

[0096]

[0097] in, Indicates phase difference,

[0098] Fifth, the low-pass filter module is used to retain the DC component (i.e., the current signal), filter out high-frequency noise and demodulation harmonics, and finally output a DC voltage proportional to the current to achieve high-precision measurement. The target voltage signal V_out output after the fundamental frequency demodulated signal is low-pass filtered is:

[0099]

[0100] Where N_LPF(t) represents the residual component of the original noise N(t) after modulation and demodulation.

[0101] When phase locked:

[0102] V_out=(1 / 2)·I(t)·R+(1 / 2)·N_eff(t);

[0103] Where N_eff(t) represents the remaining equivalent noise component after low-pass filtering (LPF).

[0104] Traditional temperature compensation methods, which use fixed coefficients, suffer from significant errors. In high-reliability applications such as new energy vehicles, these methods still fall short of meeting the demands for accurate measurement. Therefore, it is necessary to develop a current sensing technology that can simultaneously address high-frequency noise suppression, wide-temperature-range nonlinear compensation, and rapid protection optimization.

[0105] In some embodiments, please continue reading Figure 2 The current detection device also includes a temperature compensation module 300; the temperature compensation module 300 is electrically connected to the shunt 20, the amplification unit 111 and the control module 30 respectively, and is used to obtain the current temperature of the shunt 20, determine the target gain according to the current temperature and the preset temperature drift compensation strategy, and adjust the preset multiple according to the target gain.

[0106] The preset factor is the amplification factor of the first voltage signal by the amplification unit 111. This preset factor can be dynamically modulated according to the target gain, which facilitates the introduction of temperature drift compensation (compensating for the nonlinear temperature drift of the shunt 20) based on the actual temperature of the battery management system 10. Dynamically adjusting the preset factor helps to reasonably amplify the first voltage signal, thereby improving the accuracy of current detection.

[0107] The input signal to the temperature compensation module 300 is the current temperature of the shunt. The principle and function of the temperature compensation module 300 are: to establish a nonlinear relationship between the shunt sampling coefficient offset and temperature, and to correct the gain (i.e., the preset multiple) of the instrumentation amplifier in the signal modulation module based on the real-time temperature (i.e., the current temperature). The output signal of the temperature compensation module 300 is the gain adjustment digital-to-analog converter (DAC) output, i.e., the target gain.

[0108] In some embodiments, please continue reading Figure 2The temperature compensation module 300 includes a distributed temperature detection unit 310, a thermal gradient compensation circuit 320, and a gain adjustment unit 330. The distributed temperature detection unit 310 is located in the critical heat-sensitive area of ​​the shunt 20 and is used to detect the current temperature of the critical heat-sensitive area. The thermal gradient compensation circuit 320 is electrically connected to the distributed temperature detection unit 310 and is used to acquire the current temperature and historical temperature of the heat-sensitive area, divide it into multiple temperature ranges based on the historical temperature, and determine the shunt coefficient deviation corresponding to each temperature range based on the current temperature and a preset piecewise polynomial fitting algorithm. The gain adjustment unit 330 is used to determine the target gain based on a preset reference gain, a preset temperature drift compensation coefficient, and the shunt coefficient deviation corresponding to each temperature range, and adjust the target gain by a preset factor.

[0109] Figure 4 This is a flowchart of a temperature compensation algorithm provided in an embodiment of this application. For an example, please refer to [link / reference]. Figure 4 The specific implementation process of temperature compensation is as follows: A segmented model is constructed. The distributed temperature detection unit 310 is a distributed temperature sensor, which is arranged in the key heat-sensitive areas of the shunt 20 to detect the current temperature of each key sensitive area, forming a temperature matrix T = [T1, T2, ..., T...]. n For example, [-40℃, -20℃, 0℃, 25℃, 50℃, 85℃].

[0110] Historical temperatures of key heat-sensitive areas detected by the distributed temperature detection unit 310 are collected, and temperature intervals are divided based on these historical temperatures. The specific process for dividing these temperature intervals is as follows: for example, the historical temperature range of -40℃ to 85℃ is divided into M overlapping intervals (e.g., a first temperature interval of -40℃ to 0℃, a second temperature interval of -20℃ to 40℃, and a third temperature interval of 25℃ to 85℃). Abrupt changes should be avoided in the design of these overlapping intervals.

[0111] Thermal gradient compensation: Specifically, the process of determining the shunt coefficient deviation for each temperature range based on the current temperature and a preset piecewise polynomial fitting algorithm is as follows:

[0112] Output the actual shunt sampling coefficient deviation ΔB = [ΔB1, ΔB2, ..., ΔB] corresponding to the above temperature. n For example, [0.12, 0.08, 0.02, -0.01, -0.05, -0.10], to achieve three-segment piecewise fitting, as follows:

[0113]

[0114] Dynamic compensation mechanism: Specifically, the process of determining the target gain based on the preset reference gain, the preset temperature drift compensation coefficient, and the shunt coefficient deviation corresponding to each temperature range is as follows:

[0115] Referring to the aforementioned thermal gradient compensation circuit, the target gain adjustment DAC output is used to control the gain parameter G of the instrumentation amplifier. The final gain G of the instrumentation amplifier (i.e., the target gain, which is a preset multiple) is determined by the preset reference gain G0 and the temperature drift compensation gain ΔG. The temperature drift compensation gain ΔG is:

[0116] ΔG = kΔB;

[0117] Where k represents the preset temperature drift compensation coefficient, which is determined through experimental calibration.

[0118] The final gain G of the instrumentation amplifier is:

[0119] G = G0(1 + kΔB(T));

[0120] Here, G0 represents the initial reference gain (i.e., preset reference gain) of the instrumentation amplifier, which is configured by a hardware resistor network.

[0121] Figure 5 This is a schematic diagram of a non-inverting proportional operational circuit provided in an embodiment of this application. Exemplarily, the process of configuring G0 by the hardware resistor network is as follows:

[0122] For example, if G0 needs to be configured as 10, the hardware configuration would be as follows:

[0123] According to the gain formula of the instrumentation amplifier, G = 1 + Rf / Rg (where Rf is the feedback resistor and Rg is the gain resistor), its circuit diagram is as follows: Figure 5 As shown, Figure 5 In this context, R1 is equivalent to Rg, so Rf can be chosen as 9kΩ and Rg can be chosen as 1kΩ. The formulas for calculating the output voltage u0 and the second resistor R2 of the non-inverting proportional operational circuit are as follows:

[0124]

[0125] R2 = R1 / / Rf;

[0126] Where ui represents the input voltage; R1 represents the first resistor.

[0127] This embodiment utilizes the DAC output voltage to precisely control the amplification factor (i.e., the preset factor) of the instrumentation amplifier. The voltage signal output by the DAC is directly used as the reference voltage for the gain control terminal of the instrumentation amplifier, and is automatically converted into an equivalent resistance Rg by the built-in circuit. According to the gain formula of the instrumentation amplifier, G = 1 + Rf / Rg (where Rf is the feedback resistor), when the amplification factor needs to be adjusted, the system automatically calculates the required voltage value and changes the resistance value of the equivalent resistance Rg by outputting the corresponding voltage through the DAC, thereby precisely setting the amplification factor G.

[0128] For example, the experimental results of this system using the intelligent temperature drift compensation mechanism are shown in Table 1.

[0129] Table 1 Experimental Results

[0130]

[0131] It is understood that the intelligent temperature compensation module provided in this application embodiment, through a novel architecture that constructs a distributed temperature sensing network and an intelligent compensation algorithm to work together, achieves accurate compensation for the nonlinear temperature drift of the shunt 20 by using multi-sensor data fusion and dynamic algorithm selection. Specifically, it monitors the real-time temperature of the shunt in real time through the distributed temperature sensor network and dynamically adjusts the gain parameters of the instrumentation amplifier. This modular design, through signal modulation and demodulation, dual-path collaboration, dynamic compensation, and multi-mode optimization, achieves high-precision current detection across the entire temperature range (e.g., -40℃ to 85℃), and to a certain extent solves the technical problems of traditional solutions in noise suppression and temperature drift compensation.

[0132] In some embodiments, the control module 30 is further configured to: determine a target current signal based on the target voltage signal and the resistance of the shunt; and determine a current anomaly in the battery management system if the target current signal exceeds a preset current threshold, and / or, upon receiving a trigger signal.

[0133] The specific value of the preset current threshold can be set according to the actual situation, and no specific limit is made here.

[0134] Specifically, upon receiving the target voltage signal from the locking amplification module 120, the control module 30 calculates the target current signal using Ohm's law and the resistance of the shunt. It then compares the target current signal with a preset current threshold. If the target current signal exceeds the preset current threshold, it indicates an abnormal current in the battery management system 10, and the control module 30 issues corresponding current detection anomaly information. Similarly, upon receiving a trigger signal, the control module 30 indicates an abnormal current and a potential short-circuit risk, and issues corresponding current detection anomaly information.

[0135] It is understandable that the embodiments of this application achieve technological advancements through architectural innovation. An innovative architecture combining signal modulation and lock-in amplification is employed to shift weak current signals to a high-frequency carrier wave before synchronous demodulation, fundamentally solving the problem of high-frequency noise interference. Secondly, a novel architecture is constructed that integrates a distributed temperature sensing network with an intelligent compensation algorithm. Through multi-sensor data fusion and dynamic algorithm selection, accurate compensation for nonlinear temperature drift is achieved. Finally, a dual-path parallel processing architecture decouples high-precision detection from rapid protection functions. The coordinated use of hardware comparators and software algorithms resolves the conflict between protection speed and measurement accuracy.

[0136] Furthermore, the embodiments of this application achieve effective isolation from broadband interference in terms of noise suppression, ensure measurement stability across the entire temperature range in terms of temperature adaptability, and simultaneously meet the dual requirements of high-precision detection and rapid protection in terms of system reliability. Compared with traditional solutions, this application provides a new technical path for improving the performance of current detection in battery management systems. It addresses three key issues faced by traditional BMS current detection methods: first, in the signal acquisition stage, direct measurement schemes struggle to effectively isolate high-frequency switching noise; second, in terms of temperature adaptability, traditional compensation methods cannot accurately fit the nonlinear temperature drift characteristics of the shunt; and third, at the system protection level, a single detection path cannot simultaneously meet the requirements of high-precision measurement and rapid protection.

[0137] Figure 6 This is an overall architectural diagram of a current detection device provided in an embodiment of this application. For an example, please refer to [link to example diagram]. Figure 6The current detection device includes a signal modulation module 110, a lock-in amplification module 120, a short-circuit protection system 200, a temperature compensation module 300, and a control module 30. First, the signal modulation module 110 modulates the μV to mV level micro-voltage signal output from the shunt 20 onto a specific high-frequency carrier wave to shift the signal spectrum to a less noisy frequency band. The lock-in amplification module 120, through synchronous demodulation technology and low-pass filtering, accurately extracts the target current signal from the modulated signal, effectively suppressing noise interference. This application employs a unique dual-path architecture: the high-precision detection path (i.e., the signal adjustment and detection system 100) obtains accurate current values ​​through lock-in amplification, while the fast protection path (i.e., the short-circuit protection system 200) directly monitors the shunt 20 voltage using an independent hardware comparator, achieving μs-level short-circuit protection. The intelligent temperature drift compensation module (i.e., the temperature compensation module 300) monitors the shunt temperature in real time through a distributed temperature sensor network and dynamically adjusts the gain parameters of the instrumentation amplifier to compensate for the nonlinear temperature drift of the shunt. This modular design achieves high-precision current detection across the entire temperature range (-40℃ to 85℃) through signal modulation and demodulation, dual-path coordination, dynamic compensation, and multi-mode optimization, thus solving to some extent the technical problems of noise suppression and temperature drift compensation in traditional solutions. The implementation of this current detection device specifically includes the following steps:

[0138] The first step is to modulate the shunt signal onto a high-frequency carrier.

[0139] The second step is to extract the target frequency band signal by locking and amplifying, and then demodulate it.

[0140] The third step is to collect the shunt temperature in real time and dynamically adjust the gain to compensate for temperature drift.

[0141] The fourth step involves parallel processing along two paths. The high-precision signal from the current sample, after being processed by lock-in amplification, is output to the MCU. At the same time, a multi-threshold hardware comparator is used to monitor the risk of short circuits.

[0142] The fifth step is to adaptively optimize system parameters based on temperature and operating conditions.

[0143] In summary, the embodiments of this application achieve high-precision and high-reliability current detection through an innovative system architecture. Specifically, this application mainly achieves the following three core objectives:

[0144] First, it improves detection accuracy in high-frequency noise environments. Specifically, addressing the poor signal-to-noise ratio of traditional shunt solutions under noise interference, this application's embodiments introduce lock-in amplification technology into the BMS field, employing high-frequency carrier modulation and synchronous demodulation techniques to effectively isolate broadband interference. The signal modulation architecture can shift the spectrum of the microvolt-level current signal to a low-noise frequency band, and with the precise phase synchronization of the digital phase-locked loop, enhances high-frequency noise suppression capabilities.

[0145] Secondly, it achieves wide-range nonlinear temperature drift compensation. Specifically, addressing the temperature drift characteristics of the shunt, this application proposes an intelligent temperature drift compensation mechanism. This mechanism uses a distributed temperature sensor network to monitor the shunt temperature gradient in real time and, combined with a piecewise polynomial fitting algorithm, dynamically adjusts the gain parameters of the instrumentation amplifier in the signal modulation module.

[0146] Third, a detection system that balances speed and accuracy is constructed. Specifically, to resolve the conflict between protection speed and detection accuracy, this application designs a dual-path parallel processing architecture: a high-precision detection path achieves high measurement accuracy through lock-in amplification technology, while an independent hardware comparator path provides fast short-circuit protection. Multi-level threshold comparators, combined with a software secondary verification mechanism, ensure both timely protection and prevent false triggering.

[0147] Figure 7 This is a flowchart of a current detection method provided in an embodiment of this application. Correspondingly, an embodiment of this application also provides a current detection method. Please refer to... Figure 7 The current detection method includes the following steps:

[0148] Step 101: Detect the first voltage signal of the battery management system.

[0149] Step 102: Determine the target voltage signal based on the first voltage signal and the preset modulation lock-in amplification strategy.

[0150] Step 103: Monitor the first voltage signal, and output a trigger signal if the first voltage signal does not meet the preset protection conditions.

[0151] Step 104: Determine the abnormal current status of the battery management system based on the target voltage signal and the trigger signal.

[0152] The technical solution of this application provides a current detection method. By setting up a dual-path parallel processing architecture of a signal adjustment and detection system and a short-circuit protection system, and using a preset modulation lock-in amplification strategy, the noise interference problem is fundamentally solved to improve detection accuracy. Short-circuit protection is achieved through the short-circuit protection system, thereby decoupling the functions of high-precision current detection and fast protection, resolving the contradiction between protection speed and measurement accuracy, and meeting the dual requirements of high-precision measurement and fast protection.

[0153] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0154] The current detection device and method provided in the embodiments of this application have been described in detail above, and specific examples have been used to illustrate the principle and implementation of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A current detection device, characterized in that, include: The system comprises a shunt, a signal conditioning and detection system, a short-circuit protection system, and a control module; wherein the shunt is electrically connected to the battery management system and is used to detect the first voltage signal of the battery management system. The signal adjustment and detection system is electrically connected to the shunt and the control module respectively. The signal adjustment and detection system is used to determine the target voltage signal based on the first voltage signal and the preset modulation lock-in amplification strategy. The short-circuit protection system is electrically connected to the shunt and the control module respectively, and is used to monitor the first voltage signal, and output a trigger signal to the control module when the first voltage signal does not meet the preset protection conditions; The control module is used to determine the abnormal current condition of the battery management system based on the target voltage signal and the trigger signal.

2. The current detection device according to claim 1, characterized in that, The signal adjustment and detection system includes a signal modulation module and a lock-in amplification module; The signal modulation module is electrically connected to the shunt and the locked amplifier module, respectively, and the signal modulation module is used to modulate the first voltage signal into a high-frequency carrier modulation signal; The locking amplification module is electrically connected to the control module, and the locking amplification module is used to extract the target voltage signal from the high-frequency carrier modulation signal.

3. The current detection device according to claim 2, characterized in that, The signal modulation module includes: an amplification unit, a first signal generation unit, a first analog multiplication unit, and a first filtering unit; wherein, the amplification unit is used to amplify the first voltage signal by a preset factor to obtain a second voltage signal; The first signal generating unit is used to generate a carrier signal; The first analog multiplication unit is used to amplitude modulate the second voltage signal and the carrier signal to obtain a third voltage signal; The first filtering unit is used to reduce the noise of the third voltage signal to obtain the high-frequency carrier modulation signal.

4. The current detection device according to claim 3, characterized in that, The locked amplification module includes: a second signal generation unit, a second analog multiplication unit, and a second filtering unit; the second signal generation unit is used to generate a reference signal; the second analog multiplication unit is used to multiply the reference signal and the high-frequency carrier modulation signal to obtain a baseband demodulated signal; the second filtering unit is used to filter out noise from the baseband demodulated signal to obtain the target voltage signal.

5. The current detection device according to claim 3, characterized in that, The current detection device further includes a temperature compensation module; the temperature compensation module is electrically connected to the shunt, the amplification unit and the control module respectively, and is used to obtain the current temperature of the shunt, determine the target gain according to the current temperature and the preset temperature drift compensation strategy, and adjust the preset factor according to the target gain.

6. The current detection device according to claim 5, characterized in that, The temperature compensation module includes: a distributed temperature detection unit, a thermal gradient compensation circuit, and a gain adjustment unit; wherein, the distributed temperature detection unit is located in the critical heat-sensitive area of ​​the shunt and is used to detect the current temperature of the critical heat-sensitive area; The thermal gradient compensation circuit is electrically connected to the distributed temperature detection unit and is used to obtain the current temperature and historical temperature of the heat-sensitive area, divide multiple temperature intervals according to the historical temperature, and determine the shunt coefficient deviation corresponding to each temperature interval according to the current temperature and a preset piecewise polynomial fitting algorithm. The gain adjustment unit is used to determine the target gain based on the preset reference gain, the preset temperature drift compensation coefficient, and the shunt coefficient deviation corresponding to each of the temperature ranges, and adjust the preset multiple based on the target gain.

7. The current detection device according to claim 1, characterized in that, The short-circuit protection system includes a comparison module, which is used to compare the first voltage signal with a preset voltage threshold, and output the trigger signal to the control module when the first voltage signal exceeds the preset voltage threshold.

8. The current detection device according to claim 7, characterized in that, The short-circuit protection system also includes an optocoupler isolation module, which is electrically connected to the comparison module and the control module respectively, and is used to isolate and reduce noise from the trigger signal.

9. The current detection device according to claim 1, characterized in that, The control module is also used for: The target current signal is determined based on the target voltage signal and the resistance of the shunt. And if the target current signal exceeds a preset current threshold and / or if the trigger signal is received, the current abnormality of the battery management system is determined.

10. A current detection method, characterized in that, include: Detect the first voltage signal of the battery management system; The target voltage signal is determined based on the first voltage signal and a preset modulation lock-in amplification strategy; Monitor the first voltage signal, and output a trigger signal if the first voltage signal does not meet the preset protection conditions; The abnormal current condition of the battery management system is determined based on the target voltage signal and the trigger signal.

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