Battery charging method and system based on constant-current constant-voltage double-loop interlocking feedback

Abstract

The invention relates to the technical field of battery charging protection control, and discloses a battery charging method and system based on constant-current constant-voltage double-loop interlocking feedback. The battery charging method is applied to battery charging equipment, and specifically comprises the following steps: S101, starting a self-checking program to carry out impedance matching detection on feedback circuits of a constant-current control loop and a constant-voltage control loop at the moment of connecting a power supply, initializing PID parameters of a digital signal processor, and synchronously activating an interlocking protection mechanism of the constant-current loop and the constant-voltage loop; s102, collecting current Ibat of the positive electrode and the negative electrode of the battery in real time by taking a preset constant current value as a target, and converting the current Ibat into a voltage signal V through a Hall sensor; the problem that mode switching is out of control is solved through a three-level interlocking response strategy, the fault response time is compressed to be within 1 microsecond through a hardware-level RS trigger, and transition current from constant current to constant voltage is smoothly reduced through voltage overshoot and dynamic slope compensation during forced switching of overvoltage / overcurrent interlocking signals.

Description

Technical Field

[0001] The present invention relates to the technical field of battery charging protection control, and in particular to a battery charging method and system based on constant current and constant voltage dual-loop interlocking feedback. Background Art

[0002] Existing charging technologies generally adopt a sequential constant current (CC) and constant voltage (CV) mode switching strategy, which has poor stability and safety hazards during switching. When the battery voltage approaches the threshold, voltage overshoot is easily generated during the switching process from the constant current loop to the constant voltage loop, causing electrolyte decomposition and thermal runaway. At the same time, the conventional dual-loop parallel architecture generates low-frequency oscillations due to loop interference, causing the current ripple to be amplified to more than 15%, accelerating battery lithium deposition. More seriously, when the battery internal resistance suddenly changes or the contact is poor, the traditional solution relies on software protection, with a response delay of milliseconds, which cannot block the avalanche effect of nanosecond fault current.

[0003] Moreover, existing battery charging solutions lack the ability to collaboratively handle multiple faults. Temperature compensation only uses static voltage offsets and does not consider the dynamic impact of the temperature gradient change rate on the polarization voltage, resulting in lithium deposition during low-temperature charging or overcharging during high-temperature charging. The charging termination criterion relies on a fixed current threshold and does not incorporate adjustments to the battery's state of aging (SOH), resulting in undercharging of new batteries or overcharging of aged batteries, significantly reducing the system's cycle life. Summary of the Invention

[0004] The purpose of the present invention is to provide a battery charging method and system based on constant current and constant voltage dual-loop interlocking feedback, solve the problem of mode switching out of control through a three-level interlocking response strategy, compress the fault response time to less than 1μs, and reduce the voltage overshoot when the overvoltage / overcurrent interlock signal is forced to switch. Dynamic slope compensation makes the transition current from constant current to constant voltage drop smoothly, aiming to solve the problems in the prior art.

[0005] The present invention is implemented as follows: a battery charging method based on constant current and constant voltage dual-loop interlocking feedback is applied to a battery charging device, specifically comprising the following steps:

[0006] S101: When the power is turned on, the self-test program is started to perform impedance matching detection on the feedback circuits of the constant current control loop and the constant voltage control loop, and the PID parameters of the digital signal processor are initialized, and the interlocking protection mechanism of the constant current loop and the constant voltage loop is simultaneously activated;

[0007] S102: Based on the preset constant current value, real-time acquisition of the positive and negative currents of the battery I bat , which is converted into a voltage signal V by the Hall sensor. V is input into the error amplifier of the constant current loop and compared with the reference voltage corresponding to the preset constant current value to generate a current error signal ΔV I At the same time, the constant voltage loop monitors the battery terminal voltage V in real timebat ;

[0008] S103: Dynamically adjust the proportional gain Kp of the PID controller through the digital potentiometer to make ΔV I The error signal value tends to zero, and when the constant voltage loop monitors the battery terminal voltage V in real time bat Reaching the preset voltage threshold V th When the constant current loop reaches 90%, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ;

[0009] S104: The outputs of the overcurrent comparator of the constant current loop and the overvoltage comparator of the constant voltage loop are connected to the S and R terminals of the RS trigger respectively. The constant current loop monitors the battery current I in real time. bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set, and the reference voltage V th Lower until V bat When the preset value is reached, the RS trigger is reset and the fault is cleared;

[0010] S105: When the charging current in the constant voltage stage drops to 0.05C, the countdown is started to determine whether the current change rate meets the preset value of |dI / dt|<0.001C / s within the preset time. If it meets the preset value, the charging is determined to be complete, and the DSP issues a termination command. At the same time, the interlock protection mechanism remains activated until the system is powered off.

[0011] Furthermore, in S101, the interlocking protection mechanism of the constant current loop and the constant voltage loop is synchronously activated, including:

[0012] A voltage clamping diode is connected in series to the output end of the constant current loop, and a current limiting resistor is connected in parallel to the output end of the constant voltage loop. A signal isolation channel is established between the two loops through a photoelectric coupler.

[0013] When any loop detects an overvoltage or overcurrent fault, the optocoupler triggers a high-level interlock signal, forcing the other loop to enter the standby state;

[0014] The DSP records the fault code and starts the hardware watchdog timer until the difference between the dual-loop feedback voltages is less than 5mV before releasing the interlock.

[0015] Furthermore, the interlock protection mechanism includes a three-level interlock response strategy:

[0016] Primary interlock responds to battery voltage mutation, when |dV bat When / dt|>500mV / s, the constant voltage loop limits the PID output of the constant current loop to 50%;

[0017] Intermediate interlock response temperature coordination, arrange NTC thermistor at the battery terminal ear, if the temperature T>45℃ and dT / dt>1℃ / s, the constant current loop triggers the reference voltage V of the constant voltage loop th =V th -k(T-45) dynamic down-regulation;

[0018] Advanced interlock responds to hardware faults. When an abnormal MOSFET drive voltage or an open feedback loop is detected, the DSP directly forces the dual loops into a high-impedance state and maintains minimum system power supply through redundant power paths. At the same time, the fault LED is lit and an alarm is issued.

[0019] Furthermore, in S103, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ,include:

[0020] When V bat Reach V th When the constant pressure ring V bat With V th Input high-precision differential amplifier, output voltage error signal ΔV V , using a filter to ΔV V Perform ripple suppression and filter out noise components with frequencies higher than 100kHz;

[0021] The constant current loop enters the slave mode, and the gate voltage of its output stage MOSFET is modulated by the PWM signal output by the constant voltage loop;

[0022] If the constant pressure ring detects V bat If the fluctuation exceeds ±50mV within three consecutive sampling cycles, it is determined that the battery internal resistance is abnormal, and an interlock signal is immediately sent to the constant current loop, switching back to constant current mode and triggering the pulse repair charging program.

[0023] Furthermore, in S104, the constant current loop monitors the battery terminal current I in real time. bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set to close the driver chip end of the constant current loop, including:

[0024] During the full charging cycle, I bat When >I+10%, the RS trigger is set, the potential end of the driver chip of the constant current loop is closed, and the reference voltage V th 5% reduction;

[0025] When V bat >V thWhen the voltage drops to +3%, the RS trigger is reset, forcing the constant current loop output current to drop to 0, and at the same time starting the discharge circuit to transfer the excess charge into the grounding capacitor. After the fault is cleared, the interlock state needs to be manually reset.

[0026] Furthermore, in S105, the DSP issues a termination instruction, and the interlock protection mechanism remains activated until the system is powered off, including:

[0027] Disconnect the main charging MOSFET and then switch the dual-loop control signal to ground;

[0028] By I 2 The C bus sends a charging curve data packet to the BMS, wherein the charging curve data packet includes voltage extreme value, average temperature rise, and fault code data information;

[0029] The data information of the acquired charging curve data packet is used to determine whether the battery state under the protection of the interlock protection mechanism is maintained within the safety threshold data state.

[0030] Furthermore, if the preset value is met, charging is determined to be complete, including:

[0031] The battery state space model is established through Kalman filtering to determine whether charging is terminated:

[0032]

[0033] Where the state vector x=[V oc , R b , C c ] T , where V oc is the open circuit voltage, R b is the internal resistance, C c is the concentration polarization capacitance, T is the temperature value, and the observed value = [V bat , I bat ] T Change value;

[0034] The extended Kalman filter is designed to update the state estimate every 100ms. oc >0.99V th and |dR b When / dt|<0.1mΩ / s for 5 minutes, the termination condition is triggered.

[0035] Furthermore, a battery state space model is established, including:

[0036] Build a virtual battery model in the cloud and receive the following data in real time:

[0037] Timestamp t, battery voltage V bat , current I bat, temperature T, interlock event type and duration, and loop PID parameter history records to complete the construction of the digital twin monitoring system;

[0038] By building a digital twin monitoring system, the battery health status is predicted through an LSTM neural network. When the predicted battery health status is less than 80%, an adjustment instruction is sent to the charger. The adjustment instruction includes:

[0039] The target voltage V in the constant voltage stage th Reduce by 0.5%;

[0040] Increase the termination current threshold to 0.1C;

[0041] Added a battery health degradation warning icon to the charging completion report.

[0042] Compared with the prior art, the battery charging method and system based on constant current and constant voltage dual-loop interlocking feedback provided by the present invention has the following beneficial effects:

[0043] 1. A three-level interlock response strategy solves the problem of mode switching out of control. The hardware-level RS trigger compresses the fault response time to less than 1μs. The voltage overshoot during forced switching of the overvoltage / overcurrent interlock signal is reduced. Dynamic slope compensation makes the transition current from constant current to constant voltage drop smoothly, and the ripple amplitude is suppressed to below 2%. The dual-loop interlock mechanism is combined with adaptive variable gain control to adjust the PID parameters in real time according to the changes in the battery internal resistance, eliminating low-frequency oscillation and improving the system phase margin. Under 2C fast charging conditions, the battery surface temperature rise is reduced by 8-12°C, and there is no lithium plating.

[0044] 2. Through temperature-voltage composite compensation and digital twin monitoring, dynamic compensation of real-time temperature gradients improves voltage control accuracy. The cloud-based LSTM model predicts SOH by analyzing historical charging data, dynamically optimizes the termination current threshold, and extends battery cycle life. Multi-band ripple cancellation technology combines 120kHz notch filtering with digital ripple injection to suppress switching noise to below 10mVp-p. In addition, an anti-interference communication link is established, reducing the bit error rate and the mean time between failures.

[0045] A battery charging system based on constant current and constant voltage dual-loop interlocking feedback is used to perform the above-mentioned battery charging method, and the battery charging system includes:

[0046] The main control processing module is used to execute the parallel PID algorithm calculation of the constant current loop and the constant pressure loop, and to exchange the dual-loop interlock flag bits through shared memory and arbitrate the control right switch in real time;

[0047] Constant current control module, used to collect battery current, convert it into a digital signal through a 24-bit ADC, and dynamically adjust the proportional coefficient according to the adaptive gain function;

[0048] Constant voltage control module for high-precision differential amplifier measurement of battery terminal voltage and suppression of >100kHz switching noise through filters and digital ripple injection unit;

[0049] Interlock protection module, used to monitor overvoltage, overcurrent, and overtemperature faults in real time through dual-loop connections via high-speed optocouplers;

[0050] Condition monitoring module, used to calculate the battery internal resistance R b and open circuit voltage V oc When the local temperature difference is detected to be greater than 5°C, the fan is triggered to force cooling;

[0051] A power output module, which converts the constant current / constant voltage control signal into an adjustable DC output and switches to a high-impedance protection mode when an interlock event occurs;

[0052] The cloud collaboration module is used to complete the establishment of a battery virtual model and a digital twin monitoring system in the cloud.

[0053] Specifically, the cloud collaboration module includes:

[0054] Wireless communication unit, used to upload charging data to the cloud server via the MQTT protocol. The uploaded charging data includes: timestamp, battery voltage / current, temperature matrix reading, interlock event type and duration, and PID parameter history;

[0055] The digital twin engine, which runs on a cloud server, predicts the battery health status based on an LSTM neural network. Input features include the slope of the charging curve and the rate of change of internal resistance. It generates optimization instructions when the predicted battery health status is less than 80%.

[0056] The instruction execution unit is used to parse the optimization instructions sent by the cloud and update the PID parameter register of the main control processing module, and add the SOH degradation warning sign and repair suggestions to the charging report. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic flow chart of a battery charging method based on constant current and constant voltage dual-loop interlocking feedback proposed by the present invention;

[0058] Figure 2 This is a schematic block diagram of the process of activating the interlocking protection mechanism of the constant current loop and the constant voltage loop in a battery charging method based on constant current and constant voltage dual-loop interlocking feedback proposed by the present invention;

[0059] Figure 3 This is a structural diagram of a battery charging system based on constant current and constant voltage dual-loop interlocking feedback proposed by the present invention;

[0060] Figure 4This is a structural diagram of a cloud collaboration module in a battery charging system based on constant current and constant voltage dual-loop interlocking feedback proposed by the present invention. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0062] The implementation of the present invention is described in detail below with reference to specific embodiments.

[0063] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0064] Reference Figure 1-2 As shown, a battery charging method based on constant current and constant voltage dual-loop interlocking feedback is applied to a battery charging device, specifically comprising the following steps:

[0065] S101: When the power is turned on, the self-test program is started to perform impedance matching detection on the feedback circuits of the constant current control loop and the constant voltage control loop, and the PID parameters of the digital signal processor are initialized, and the interlocking protection mechanism of the constant current loop and the constant voltage loop is synchronously activated;

[0066] Among them, the interlocking protection mechanism of synchronously activating the constant current loop and the constant voltage loop includes:

[0067] A voltage clamping diode is connected in series to the output end of the constant current loop, and a current limiting resistor is connected in parallel to the output end of the constant voltage loop. A signal isolation channel is established between the two loops through a photoelectric coupler.

[0068] When any loop detects an overvoltage or overcurrent fault, the optocoupler triggers a high-level interlock signal, forcing the other loop to enter the standby state;

[0069] The DSP records the fault code and starts the hardware watchdog timer until the difference between the dual-loop feedback voltages is less than 5mV, which is the time to release the interlock.

[0070] S102: Based on the preset constant current value, real-time acquisition of the positive and negative currents of the battery I bat, which is converted into a voltage signal V by the Hall sensor. V is input into the error amplifier of the constant current loop and compared with the reference voltage corresponding to the preset constant current value to generate a current error signal ΔV I At the same time, the constant voltage loop monitors the battery terminal voltage V in real time bat ;

[0071] S103: Dynamically adjust the proportional gain Kp of the PID controller through the digital potentiometer to make ΔV I The error signal value tends to zero, and when the constant voltage loop monitors the battery terminal voltage V in real time bat Reaching the preset voltage threshold V th When the constant current loop reaches 90%, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ;

[0072] Among them, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ,include:

[0073] When V bat Reach V th When the constant pressure ring V bat With V th Input high-precision differential amplifier, output voltage error signal ΔV V , using a filter to ΔV V Perform ripple suppression and filter out noise components with frequencies higher than 100kHz;

[0074] The constant current loop enters the slave mode, and the gate voltage of its output stage MOSFET is modulated by the PWM signal output by the constant voltage loop;

[0075] If the constant pressure ring detects V bat If the fluctuation exceeds ±50mV within three consecutive sampling cycles, it is determined that the battery internal resistance is abnormal, and an interlock signal is immediately sent to the constant current loop, switching back to constant current mode and triggering the pulse repair charging program;

[0076] S104: The outputs of the overcurrent comparator of the constant current loop and the overvoltage comparator of the constant voltage loop are connected to the S and R terminals of the RS trigger respectively. The constant current loop monitors the battery current I in real time. bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set, and the reference voltage V th Lower until V bat When the preset value is reached, the RS trigger is reset and the fault is cleared;

[0077] Among them, the constant current loop monitors the battery terminal current I in real time bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set to close the driver chip end of the constant current loop, including:

[0078] During the full charging cycle, I bat When >I+10%, the RS trigger is set, the potential end of the driver chip of the constant current loop is closed, and the reference voltage V th 5% reduction;

[0079] When V bat >V th When the voltage drops to +3%, the RS trigger is reset, forcing the constant current loop output current to drop to 0, and at the same time starting the discharge circuit to transfer the excess charge into the grounding capacitor. After the fault is cleared, the interlock state needs to be manually reset.

[0080] S105: When the charging current in the constant voltage stage drops to 0.05C, a countdown is started to determine whether the current change rate meets the preset value of |dI / dt|<0.001C / s within the preset time. If it meets the preset value, charging is determined to be complete, and the DSP issues a termination command. At the same time, the interlock protection mechanism remains activated until the system is powered off;

[0081] If the preset value is met, charging is determined to be complete, including:

[0082] The battery state space model is established through Kalman filtering to determine whether charging is terminated:

[0083]

[0084] Where the state vector x=[V oc , R b , C c ] T , where V oc is the open circuit voltage, R b is the internal resistance, C c is the concentration polarization capacitance, T is the temperature value, and the observed value = [V bat , I bat ] T Change value;

[0085] The extended Kalman filter is designed to update the state estimate every 100ms. oc >0.99V th and |dR bWhen / dt∣<0.1mΩ / s for 5 minutes, the termination condition is triggered. The three-level interlock response strategy is used to solve the problem of mode switching out of control. The hardware-level RS trigger compresses the fault response time to less than 1μs. The voltage overshoot during forced switching of the overvoltage / overcurrent interlock signal is reduced, and dynamic slope compensation makes the transition current from constant current to constant voltage smoothly decrease, and the ripple amplitude is suppressed to below 2%. The dual-loop interlock mechanism is combined with adaptive variable gain control to adjust the PID parameters in real time according to the change of battery internal resistance, eliminate low-frequency oscillation and improve the system phase margin. Under 2C fast charging conditions, the battery surface temperature rise is reduced by 8-12℃, and there is no lithium plating phenomenon.

[0086] In S101 of this embodiment, the interlock protection mechanism includes a three-level interlock response strategy:

[0087] Primary interlock responds to battery voltage mutation, when |dV bat When / dt|>500mV / s, the constant voltage loop limits the PID output of the constant current loop to 50%;

[0088] Intermediate interlock response temperature coordination, arrange NTC thermistor at the battery terminal ear, if the temperature T>45℃ and dT / dt>1℃ / s, the constant current loop triggers the reference voltage V of the constant voltage loop th =V th -k(T-45) dynamic down-regulation;

[0089] Advanced interlock responds to hardware faults. When an abnormal MOSFET drive voltage or an open feedback loop is detected, the DSP directly forces the dual loops into a high-impedance state and maintains minimum system power supply through redundant power paths. At the same time, the fault LED is lit and an alarm is issued.

[0090] In S105 of this embodiment, the DSP issues a termination instruction, and the interlock protection mechanism remains activated until the system is powered off, including:

[0091] Disconnect the main charging MOSFET and then switch the dual-loop control signal to ground;

[0092] By I 2 The C bus sends a charging curve data packet to the BMS, which contains information on voltage extremes, average temperature rise, and fault code data.

[0093] The data information of the acquired charging curve data packet is used to determine whether the battery state under the protection of the interlock protection mechanism is maintained within the safety threshold data state.

[0094] In this embodiment, establishing a battery state space model includes:

[0095] Build a virtual battery model in the cloud and receive the following data in real time:

[0096] Timestamp t, battery voltage V bat , current I bat , temperature T, interlock event type and duration, and loop PID parameter history records to complete the construction of the digital twin monitoring system;

[0097] By building a digital twin monitoring system, the battery health status is predicted through an LSTM neural network. When the predicted battery health status is less than 80%, an adjustment instruction is sent to the charger. The adjustment instruction includes:

[0098] The target voltage V in the constant voltage stage th Reduce by 0.5%;

[0099] Increase the termination current threshold to 0.1C;

[0100] Added a battery health degradation warning icon to the charging completion report.

[0101] This technical solution uses temperature-voltage composite compensation and digital twin monitoring, and dynamic compensation of real-time temperature gradients to improve voltage control accuracy. The cloud-based LSTM model predicts SOH by analyzing historical charging data, dynamically optimizes the termination current threshold, and extends battery cycle life. Multi-band ripple cancellation technology combines 120kHz notch filtering with digital ripple injection to suppress switching noise to below 10mVp-p. In addition, an anti-interference communication link is constructed, reducing the bit error rate and the mean time between failures.

[0102] Reference Figure 3-4 As shown, a battery charging system based on constant current and constant voltage dual-loop interlocking feedback is used to execute the above-mentioned battery charging method. The battery charging system includes: a main control processing module, which is used to execute parallel PID algorithm calculation of the constant current loop and the constant voltage loop, and to exchange the dual-loop interlocking flag bit through shared memory to arbitrate the control right switch in real time; a constant current control module, which is used to collect battery current, convert it into a digital signal through a 24-bit ADC, and dynamically adjust the proportional coefficient according to the adaptive gain function; a constant voltage control module, which is used to measure the battery terminal voltage through a high-precision differential amplifier and suppress >100kHz switching noise through a filter and a digital ripple injection unit; an interlock protection module, which is used to connect the dual loops through a high-speed optical coupler to monitor overvoltage, overcurrent, and overtemperature faults in real time; and a status monitoring module, which is used to calculate the battery internal resistance R b and open circuit voltage V oc The real-time estimated value of the battery is generated, and when a local temperature difference of >5°C is detected, the fan is triggered to force heat dissipation; the power output module is used to convert the constant current / constant voltage control signal into an adjustable DC output and switch to high-impedance protection mode when an interlocking event occurs; the cloud collaboration module is used to complete the construction of the battery virtual model and the digital twin monitoring system in the cloud.

[0103] In this embodiment, the cloud collaboration module includes:

[0104] The wireless communication unit is used to upload charging data to the cloud server through the MQTT protocol. The uploaded charging data includes: timestamp, battery voltage / current, temperature matrix reading, interlock event type and duration, and PID parameter history. The digital twin engine is used to run on the cloud server and predict the battery health status based on the LSTM neural network. The input features include the slope of the charging curve and the internal resistance change rate. When the predicted battery health status is <80%, optimization instructions are generated; the instruction execution unit is used to parse the optimization instructions issued by the cloud and update the PID parameter register of the main control processing module, and attach the SOH decay warning sign and repair suggestions to the charging report.

[0105] The present invention realizes smooth transition and state self-healing of mode switching by constructing a dual-loop interlocking feedback mechanism, combining dynamic threshold calculation, multi-parameter fusion judgment and hardware-level mutual exclusion design, fundamentally avoiding the voltage / current mutation problem during the switching process, and solving the mode switching out-of-control problem through a three-level interlocking response strategy. The ripple amplitude is suppressed to below 2%. The dual-loop interlocking mechanism is combined with adaptive variable gain control to adjust the PID parameters in real time according to the change of battery internal resistance, eliminating low-frequency oscillation and improving the system phase margin. Under 2C fast charging conditions, the battery surface temperature rise is reduced by 8-12°C, and there is no lithium precipitation phenomenon. Through temperature-voltage composite compensation and digital twin monitoring, dynamic compensation of real-time temperature gradient improves the voltage control accuracy. The cloud-based LSTM model predicts SOH by analyzing historical charging data, dynamically optimizes the termination current threshold, and extends the battery cycle life. Multi-band ripple cancellation technology combines 120kHz notch filtering and digital ripple injection to suppress switching noise to below 10mVp-p. In addition, an anti-interference communication link is constructed to reduce the bit error rate and the mean time between failures.

[0106] In this embodiment, the entire operation process can be controlled by a computer to provide signal feedback to implement the steps in sequence. These are all conventional knowledge of current automated control and will not be described in detail in this embodiment.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback, characterized in that: Applied to battery charging equipment, specifically including the following steps: S101: When the power is turned on, the self-test program is started to perform impedance matching detection on the feedback circuits of the constant current control loop and the constant voltage control loop, and the PID parameters of the digital signal processor are initialized, and the interlocking protection mechanism of the constant current loop and the constant voltage loop is simultaneously activated; S102: Based on the preset constant current value, real-time acquisition of the positive and negative currents of the battery I bat , which is converted into a voltage signal V by the Hall sensor. V is input into the error amplifier of the constant current loop and compared with the reference voltage corresponding to the preset constant current value to generate a current error signal ΔV I At the same time, the constant voltage loop monitors the battery terminal voltage V in real time bat ; S103: Dynamically adjust the proportional gain Kp of the PID controller through the digital potentiometer to make ΔV I The error signal value tends to zero, and when the constant voltage loop monitors the battery terminal voltage V in real time bat Reaching the preset voltage threshold V th When the constant current loop reaches 90%, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ; S104: The outputs of the overcurrent comparator of the constant current loop and the overvoltage comparator of the constant voltage loop are connected to the S and R terminals of the RS trigger respectively. The constant current loop monitors the battery current I in real time. bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set, and the reference voltage V th Lower until V bat When the preset value is reached, the RS trigger is reset and the fault is cleared; S105: When the charging current in the constant voltage stage drops to 0.05C, the countdown is started to determine whether the current change rate meets the preset value of |dI / dt|<0.001C / s within the preset time. If it meets the preset value, the charging is determined to be complete, and the DSP issues a termination command. At the same time, the interlock protection mechanism remains activated until the system is powered off.

2. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 1, characterized in that: In S101, the interlocking protection mechanism of the constant current loop and the constant voltage loop is activated synchronously, including: A voltage clamping diode is connected in series to the output end of the constant current loop, and a current limiting resistor is connected in parallel to the output end of the constant voltage loop. A signal isolation channel is established between the two loops through a photoelectric coupler. When any loop detects an overvoltage or overcurrent fault, the optocoupler triggers a high-level interlock signal, forcing the other loop to enter the standby state; The DSP records the fault code and starts the hardware watchdog timer until the difference between the dual-loop feedback voltages is less than 5mV before releasing the interlock.

3. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 2, characterized in that: The interlock protection mechanism includes a three-level interlock response strategy: Primary interlock responds to battery voltage mutation, when |dV bat When / dt|>500mV / s, the constant voltage loop limits the PID output of the constant current loop to 50%; Intermediate interlock response temperature coordination, arrange NTC thermistor at the battery terminal ear, if the temperature T>45℃ and dT / dt>1℃ / s, the constant current loop triggers the reference voltage V of the constant voltage loop th =V th -k(T-45) dynamic down-regulation; Advanced interlock responds to hardware faults. When an abnormal MOSFET drive voltage or an open feedback loop is detected, the DSP directly forces the dual loops into a high-impedance state and maintains minimum system power supply through redundant power paths. At the same time, the fault LED is lit and an alarm is issued.

4. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 3, characterized in that: In S103, the constant voltage loop sends a pre-switching instruction to the constant current loop, and the constant current loop starts the slope compensation circuit to reduce the preset constant current value until V bat =V th ,include: When V bat Reach V th When the constant pressure ring V bat With V th Input high-precision differential amplifier, output voltage error signal ΔV V , using a filter to ΔV V Perform ripple suppression and filter out noise components with frequencies higher than 100kHz; The constant current loop enters the slave mode, and the gate voltage of its output stage MOSFET is modulated by the PWM signal output by the constant voltage loop; If the constant pressure ring detects V bat If the fluctuation exceeds ±50mV within three consecutive sampling cycles, it is determined that the battery internal resistance is abnormal, and an interlock signal is immediately sent to the constant current loop, switching back to constant current mode and triggering the pulse repair charging program.

5. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 4, characterized in that: In S104, the constant current loop monitors the battery terminal current I in real time. bat , I is detected during the full charging cycle bat When the preset range is exceeded, the RS trigger is set to close the driver chip end of the constant current loop, including: During the full charging cycle, I bat When >I+10%, the RS trigger is set, the potential end of the driver chip of the constant current loop is closed, and the reference voltage V th 5% reduction; When V bat >V th When the voltage drops to +3%, the RS trigger is reset, forcing the constant current loop output current to drop to 0, and at the same time starting the discharge circuit to transfer the excess charge into the grounding capacitor. After the fault is cleared, the interlock state needs to be manually reset.

6. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 5, characterized in that: In S105, the DSP issues a termination instruction, and the interlock protection mechanism remains activated until the system is powered off, including: Disconnect the main charging MOSFET and then switch the dual-loop control signal to ground; By I 2 The C bus sends a charging curve data packet to the BMS, wherein the charging curve data packet includes voltage extreme value, average temperature rise, and fault code data information; The data information of the acquired charging curve data packet is used to determine whether the battery state under the protection of the interlock protection mechanism is maintained within the safety threshold data state.

7. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 6, characterized in that: If the preset value is met, charging is considered complete, including: The battery state space model is established through Kalman filtering to determine whether charging is terminated: Where the state vector x=[V oc , R b , C c ] T , where V oc is the open circuit voltage, R b is the internal resistance, C c is the concentration polarization capacitance, T is the temperature value, and the observed value = [V bat , I bat ] T Change value; The extended Kalman filter is designed to update the state estimate every 100ms. oc >0.99V th and |dR b When / dt|<0.1mΩ / s for 5 minutes, the termination condition is triggered.

8. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 7, characterized in that: Establish a battery state space model, including: Build a virtual battery model in the cloud and receive the following data in real time: Timestamp t, battery voltage V bat , current I bat , temperature T, interlock event type and duration, and loop PID parameter history records to complete the construction of the digital twin monitoring system; By building a digital twin monitoring system, the battery health status is predicted through an LSTM neural network. When the predicted battery health status is less than 80%, an adjustment instruction is sent to the charger. The adjustment instruction includes: The target voltage V in the constant voltage stage th Reduce by 0.5%; Increase the termination current threshold to 0.1C; Added a battery health degradation warning icon to the charging completion report.

9. A battery charging system based on constant current and constant voltage dual-loop interlocking feedback, characterized in that: Used to execute the battery charging method according to any one of claims 1 to 8, the battery charging system comprising: The main control processing module is used to execute the parallel PID algorithm calculation of the constant current loop and the constant pressure loop, and to exchange the dual-loop interlock flag bits through shared memory and arbitrate the control right switch in real time; Constant current control module, used to collect battery current, convert it into a digital signal through a 24-bit ADC, and dynamically adjust the proportional coefficient according to the adaptive gain function; Constant voltage control module for high-precision differential amplifier measurement of battery terminal voltage and suppression of >100kHz switching noise through filters and digital ripple injection unit; Interlock protection module, used to monitor overvoltage, overcurrent, and overtemperature faults in real time through dual-loop connections via high-speed optocouplers; Condition monitoring module, used to calculate the battery internal resistance R b and open circuit voltage V oc When the local temperature difference is detected to be greater than 5°C, the fan is triggered to force cooling; A power output module, which converts the constant current / constant voltage control signal into an adjustable DC output and switches to a high-impedance protection mode when an interlock event occurs; The cloud collaboration module is used to complete the establishment of a battery virtual model and a digital twin monitoring system in the cloud.

10. A battery charging method based on constant current and constant voltage dual-loop interlocking feedback as claimed in claim 9, characterized in that: The cloud collaboration module includes: Wireless communication unit, used to upload charging data to the cloud server via the MQTT protocol. The uploaded charging data includes: timestamp, battery voltage / current, temperature matrix reading, interlock event type and duration, and PID parameter history; The digital twin engine, which runs on a cloud server, predicts the battery health status based on an LSTM neural network. Input features include the slope of the charging curve and the rate of change of internal resistance. It generates optimization instructions when the predicted battery health status is less than 80%. The instruction execution unit is used to parse the optimization instructions sent by the cloud and update the PID parameter register of the main control processing module, and add the SOH degradation warning sign and repair suggestions to the charging report.

Images