Household energy storage method and device for full-digital voltage and current double-closed-loop control

Abstract

The invention relates to the technical field of household energy storage, and particularly provides a household energy storage method and device for full-digital voltage and current double closed-loop control, a voltage sensor monitors the voltage at the positive and negative ends of a battery module in real time, a current sensor is connected in series on a line between the battery module and a bidirectional DC / DC converter, and the current flowing through the line is measured; collected analog signals are transmitted to the A / D converter, converted into digital signals and transmitted to the controller; the controller operates a full-digital double-closed-loop control algorithm, PID parameters of a voltage outer loop and a current inner loop are dynamically adjusted according to the real-time data, a generated control instruction is converted into an actual power control signal, and a power amplifier switching device is adopted. Compared with the prior art, the voltage and current can be accurately controlled, and the control precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of household energy storage, and specifically provides a household energy storage method and device with full digital voltage and current double closed-loop control. Background Art

[0002] In the development history of household energy storage systems, early control technologies were mainly based on simple open-loop control. Open-loop control operates based on preset fixed parameters and does not consider the state changes of the battery during the actual charging and discharging process. For example, when charging, charging is performed according to the set fixed current and voltage values, regardless of the actual capacity, internal resistance, and remaining power of the battery. This control method may be able to barely maintain basic charging and discharging functions when facing ordinary small-capacity batteries, but when applied to large-capacity batteries such as 100Ah square shell batteries, the disadvantages are exposed. Because the charging and discharging characteristics of large-capacity batteries are more complex, open-loop control cannot adjust parameters in real time according to their actual state, resulting in overcharging during charging, which not only accelerates battery aging and shortens battery life, but also greatly increases safety risks, such as battery bulging and even fire and explosion.

[0003] With the development of technology, single closed-loop control methods have gradually been applied to household energy storage systems. Single closed-loop control is mainly divided into voltage single closed-loop control and current single closed-loop control. Voltage single closed-loop control compares the actual voltage of the battery with the set target voltage, and adjusts the charging or discharging parameters according to the voltage deviation, but this method ignores the impact of current on battery performance and life. During the charging and discharging process of 100Ah square shell batteries, the magnitude and stability of the current have an important influence on the chemical reaction inside the battery. If you only pay attention to the voltage and do not control the current, the current may be too large during charging, causing severe heating of the battery cell, accelerating the loss of internal battery materials, and affecting the consistency and cycle life of the battery.

[0004] The current single closed-loop control only performs feedback control on the current, and adjusts the charging and discharging process according to the deviation between the set current value and the actual measured current value. However, this method ignores the key role of voltage on the battery. For a 100Ah square shell battery cell, during the discharge process, if only the current is stable without monitoring the voltage, and the battery voltage is too low and continues to discharge, it will cause over-discharge and seriously damage the battery performance.

[0005] In addition, whether it is open-loop control or single-closed-loop control, it seems inadequate when facing the thermal management and consistency issues during the charging and discharging process of 100Ah square-shell battery cells. Large-capacity battery cells generate a large amount of heat during charging and discharging. If heat dissipation management cannot be carried out in a timely and effective manner, the excessive temperature of the battery cells will further affect their performance and safety. At the same time, due to certain individual differences in the production process of battery cells, after being connected in series and parallel to form a battery pack, consistency issues are likely to occur, that is, parameters such as the voltage, capacity, and internal resistance of each battery cell are inconsistent. Traditional control methods cannot effectively compensate for and adjust these differences, resulting in a decline in the overall performance of the battery pack and the inability to fully utilize the advantages of 100Ah square-shell battery cells.

[0006] With the continuous improvement of the performance and safety requirements of households for energy storage systems, and the increasingly wide application of 100Ah square-shell battery cells in the household energy storage field, it is urgent to develop an advanced control technology that can comprehensively consider the precise control of voltage and current, and at the same time effectively solve the thermal management and consistency problems. Summary of the Invention

[0007] The present invention aims at the deficiencies of the above-mentioned existing technologies and provides a household energy storage method with strong practicability and full-digital voltage and current double-closed-loop control.

[0008] A further technical task of the present invention is to provide a household energy storage device with reasonable design, safety and applicability and full-digital voltage and current double-closed-loop control.

[0009] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0010] A household energy storage method with full-digital voltage and current double-closed-loop control. The voltage sensor monitors the voltage at both ends of the positive and negative poles of the battery module in real time. The current sensor is connected in series on the line between the battery module and the bidirectional DC / DC converter to measure the current flowing through this line. The collected analog signal is transmitted to the A / D converter, which converts it into a digital signal and transmits it to the controller.

[0011] The controller runs a full-digital double-closed-loop control algorithm. According to these real-time data, the PID parameters of the voltage outer loop and the current inner loop are dynamically adjusted. The generated control instruction is converted into an actual power control signal, and a power amplifier switching device is used.

[0012] Furthermore, the full-digital double-closed-loop control algorithm includes voltage outer loop control and current inner loop control. The voltage outer loop control takes the battery target voltage set by the user as a reference, and combines the real-time state of charge and health state of the battery to construct a dynamic voltage reference model.

[0013] When facing a 100Ah energy storage battery module, an adaptive filtering algorithm is used to preprocess the actually collected voltage. When calculating the voltage deviation adjustment amount through a PID regulator, fuzzy control rules are introduced, and the PID parameters are dynamically adjusted according to the SOC and temperature information of the battery.

[0014] Furthermore, when the battery SOC is close to the full charge state, the proportional coefficient is automatically reduced to prevent voltage overshoot; when the battery temperature is too high, the integral coefficient is increased to accelerate the correction of the voltage deviation.

[0015] Furthermore, in the current inner loop control, based on the current reference value output by the voltage outer loop, combined with the real-time change of the battery internal resistance and the charge and discharge power demand, the current control strategy is further optimized;

[0016] The predictive control algorithm is adopted to predict the current change trend in the next period of time according to the historical current data and the current operating state of the battery, and the control signal is adjusted in advance to achieve the forward-looking control of the charge and discharge current. At the same time, a ripple suppression circuit is designed, and a current ripple compensation link is added to the control algorithm.

[0017] Furthermore, in the current inner loop control, the specific operation is as follows:

[0018] Based on the current reference value output by the voltage outer loop, the controller compares it with the actually collected current value. The charging current reference value given by the voltage outer loop is a certain value, and the actually measured current is a certain value. Through the PID regulator, the adjustment amount for this current deviation is calculated;

[0019] Finally, this adjustment amount is converted into a control signal, which is amplified and then acts on the power switch device IGBT. By controlling the on and off time and frequency of the power switch device IGBT, the charge and discharge current is adjusted to approach the target value.

[0020] Furthermore, in the controller, when the battery is close to full charge, the internal resistance of the battery will change, changing the change characteristic of the charging current. At this time, the controller can automatically identify this change, adjust the PID parameters, and make the current drop smoothly to avoid overcharging.

[0021] Furthermore, during the discharge process, if the load changes, changing the current demand, the controller responds and stabilizes the output current by adjusting the control signal to ensure the stable operation of the system.

[0022] A household energy storage device with a fully digital voltage and current double closed-loop control includes: at least one memory and at least one processor;

[0023] The at least one memory is used to store machine-readable programs;

[0024] The at least one processor is used to call the machine-readable program and execute a household energy storage method with fully digital voltage-current double closed-loop control.

[0025] Compared with the prior art, a household energy storage method, device and system with fully digital voltage-current double closed-loop control of the present invention have the following outstanding beneficial effects:

[0026] The present invention constructs a fully digital voltage-current double closed-loop control technology system, combines a dynamic voltage reference model, an adaptive filtering algorithm, and fuzzy control rules to adjust PID parameters, realizes precise control of voltage and current, and improves control accuracy.

[0027] The predictive control algorithm is adopted to adjust the control signal in advance, and a ripple suppression circuit and a current ripple compensation link are designed to ensure smooth and stable output current and enhance the stability of the system under various working conditions.

[0028] A multi-core high-performance microcontroller is adopted, different core tasks are divided, a high-speed large-capacity memory and flash memory are equipped, and at the same time, communication interfaces are enriched to realize efficient data processing and intelligent interaction of the system. Specific embodiments

[0029] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0030] The following gives a best embodiment:

[0031] In a household energy storage method with fully digital voltage-current double closed-loop control in this embodiment, a voltage sensor monitors the voltage across the positive and negative terminals of the battery module in real time. A current sensor is connected in series on the line between the battery module and the bidirectional DC / DC converter to measure the current flowing through this line. The collected analog signal is transmitted to an A / D converter, which converts it into a digital signal and transmits it to the controller;

[0032] The controller runs a fully digital double closed-loop control algorithm. According to these real-time data, the PID parameters of the voltage outer loop and the current inner loop are dynamically adjusted. The generated control instruction is converted into an actual power control signal, and a power amplifier switching device is adopted.

[0033] The fully digital double closed-loop control algorithm includes voltage outer-loop control and current inner-loop control. In the voltage outer-loop control, based on the battery target voltage set by the user, combined with the real-time state of charge (SOC) and state of health (SOH) of the battery, a dynamic voltage reference model is constructed.

[0034] When facing a 100Ah energy storage battery module, fully consider the changes in the voltage platform characteristics during its charge and discharge process. Use an adaptive filtering algorithm to preprocess the actual voltage collected, remove noise interference, and improve the voltage detection accuracy. When calculating the voltage deviation adjustment amount through a PID regulator, introduce fuzzy control rules, and dynamically adjust the PID parameters according to multi-dimensional information such as the SOC and temperature of the battery. For example, when the battery SOC is close to the full charge state, automatically reduce the proportional coefficient to prevent voltage overshoot; when the battery temperature is too high, increase the integral coefficient to speed up the correction of the voltage deviation, ensuring that the charging voltage is always stable within a safe and efficient range.

[0035] After the controller receives the voltage data from the data acquisition module, it compares it with the battery target voltage set by the user. For example, if the set charging cut-off voltage is 54.6V and the currently collected battery voltage is 50V, a voltage deviation is generated at this time. The controller calculates an adjustment amount based on this voltage deviation through a PID (Proportional-Integral-Derivative) regulator. This adjustment amount is not directly used to control charge and discharge, but as the reference value for the current inner-loop. The proportional link responds quickly according to the current deviation size, the integral link is used to eliminate the deviation accumulated over a long time, and the derivative link predicts the change trend of the deviation, so that the PID regulator can give a more accurate adjustment amount by synthesizing various factors.

[0036] In the current inner-loop control, based on the current reference value output by the voltage outer-loop, combined with the real-time change of the battery internal resistance and the charge and discharge power requirements, further optimize the current control strategy. Adopt a predictive control algorithm, according to the historical current data and the current operating state of the battery, predict the current change trend in the next period of time, and adjust the control signal in advance to achieve forward-looking control of the charge and discharge current. At the same time, aiming at the problems of large charge and discharge current and easy generation of current ripple in the 100Ah energy storage battery module, design a ripple suppression circuit and add a current ripple compensation link to the control algorithm to ensure the smooth and stable output current and reduce the damage to the battery and electrical equipment.

[0037] Taking the current reference value output by the voltage outer loop as a benchmark, the controller compares it with the actually measured current value. Suppose the charging current reference value given by the voltage outer loop is 10A, while the actually measured current is 8A, then a current deviation is generated. Again, through the PID regulator, the adjustment amount for this current deviation is calculated. Finally, this adjustment amount is converted into a control signal, which is amplified and then acts on the power switch device (such as IGBT). By controlling the on and off time and frequency of the IGBT, the charge and discharge current is precisely adjusted to approach the target value.

[0038] Based on these real-time data, the controller dynamically adjusts the PID parameters of the voltage outer loop and the current inner loop. For example, when the battery is approaching full charge, the internal resistance of the battery changes, resulting in a change in the charging current characteristics. At this time, the controller can automatically identify this change and adjust the PID parameters to make the current drop smoothly and avoid overcharging.

[0039] Similarly, during the discharge process, if the load changes, resulting in a change in the current demand, the controller can also respond quickly. By adjusting the control signal, the output current is stabilized to ensure the stable operation of the system.

[0040] Example of charge and discharge control in the daily household electricity usage scenario:

[0041] Scenario setting: A household energy storage system equipped with a 100Ah energy storage battery module is installed in a certain household. This system is connected to the solar panels on the roof and is also connected to the household power grid and various electrical appliances.

[0042] Charging process: When there is sufficient sunlight during the day, the solar panels generate electrical energy. The data acquisition module continuously monitors parameters such as the output voltage and current of the solar panels, as well as the voltage, current, and temperature of the battery module. Based on the dual-loop control algorithm, the controller first constructs a voltage reference model according to the real-time SOC of the battery and the target full charge voltage. Since the SOC of the battery is relatively low at this time, the voltage outer loop uses the PID regulator combined with fuzzy control rules to give a relatively large charging current reference value. The current inner loop adjusts the control signal in advance according to the real-time change of the battery internal resistance and this reference value, and drives the IGBT in the execution module to charge the battery with appropriate on and off times. During the charging process, if the temperature sensor detects an increase in the battery temperature, the controller automatically increases the integral coefficient of the voltage outer loop PID regulator to slow down the increase rate of the charging current and prevent the battery from overheating. At the same time, the ripple suppression circuit and the current ripple compensation link ensure that the charging current is smooth and stable, avoiding damage to the battery.

[0043] Discharge process: At night, the solar panels stop generating electricity and the household electricity demand starts. At this time, the battery module begins to discharge. The controller dynamically adjusts the control parameters of the voltage outer loop and the current inner loop based on the real-time household electricity power demand and information such as the SOC and SOH of the battery. The voltage outer loop ensures that the battery discharge voltage is stable within a safe range, and the current inner loop adjusts the discharge current in real time according to the load change to ensure the normal operation of household electrical appliances. For example, when a high-power electrical appliance is turned on at home, the controller responds quickly and increases the discharge current by adjusting the switching state of the IGBT to meet the electricity demand; when some electrical appliances are turned off and the electricity power consumption decreases, the controller reduces the discharge current in a timely manner to maintain a reasonable discharge rate of the battery and extend the battery life.

[0044] Example of emergency power supply scenario for grid faults:

[0045] Scenario setting: In a certain area, a sudden grid fault occurs, and the household energy storage system of this family switches to the independent power supply mode to ensure the basic household electricity demand.

[0046] Power supply process: When the grid power outage signal is detected, the controller immediately activates the emergency power supply strategy. The data acquisition module continuously monitors the state parameters of the battery module. The voltage outer loop aims to ensure the normal operation of basic household electrical appliances with a voltage that combines the current SOC and remaining power of the battery to adjust the voltage reference value. The current inner loop uses a predictive control algorithm to plan the change of the discharge current in advance according to the power demand of household emergency electrical appliances. The drive module and the execution module cooperate closely to accurately control the conduction and cut-off of the IGBT to stably supply power to basic household electrical appliances such as lighting equipment, refrigerators, and routers in the family. At the same time, the overvoltage, overcurrent, overheat protection circuits and fault diagnosis circuits of the system monitor the whole process to ensure the safe operation of the energy storage system during the emergency power supply process. Once it is detected that the battery SOC is too low and will soon be unable to meet the power supply demand, the controller sends a warning signal to the user, prompting the user to arrange electricity consumption reasonably and wait for the grid to resume or take other emergency measures.

[0047] Among them, the drive module designs a drive circuit based on new power semiconductor devices such as silicon carbide (SiC), and uses its characteristics of high switching speed and low on-resistance to improve the efficiency and response speed of the drive module. In view of the large charge and discharge current of the 100Ah energy storage battery module, a multi-module parallel connection method is adopted to enhance the drive ability, and the current sharing technology is used to ensure uniform current distribution among the parallel modules. In addition, overvoltage, overcurrent, and overheat protection circuits are integrated in the drive module. Once an abnormal situation is detected, the drive signal is quickly cut off to protect the power switch device and the safety of the entire system.

[0048] The power switch device in the execution module adopts an advanced IGBT module, combined with an optimized heat dissipation fin and a liquid cooling system, which effectively reduces the temperature of the device during high-current operation, improves its reliability and service life. Through an intelligent gate drive circuit, the on and off times of the IGBT are precisely controlled to achieve precise control of the charge and discharge current. At the same time, a fault diagnosis circuit is added to the execution module to monitor the working state of the power switch device in real time. Once a device fault is detected, an alarm signal is immediately sent to the controller so that timely measures can be taken for repair or switching to a standby device to ensure the continuous and stable operation of the system.

[0049] Based on the above method, a household energy storage device with a fully digital voltage and current double closed-loop control in this embodiment includes: at least one memory and at least one processor;

[0050] The at least one memory is used to store machine-readable programs;

[0051] The at least one processor is used to call the machine-readable program and execute a household energy storage method with a fully digital voltage and current double closed-loop control.

[0052] The above specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the above specific embodiments. Any technical solution that conforms to the above specific embodiments of the present invention and any appropriate changes or substitutions made by those of ordinary skill in the art shall fall within the patent protection scope of the present invention.

[0053] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A household energy storage method with fully digital voltage and current double closed-loop control, characterized in that The voltage sensor monitors the voltage across the positive and negative terminals of the battery module in real time. The current sensor is connected in series on the line between the battery module and the bidirectional DC / DC converter to measure the current flowing through this line. The analog signals collected are transmitted to the A / D converter, which converts them into digital signals and then transmits them to the controller. The controller runs a fully digital dual-loop control algorithm. Based on this real-time data, it dynamically adjusts the PID parameters of the voltage outer loop and the current inner loop. The generated control instructions are converted into actual power control signals, and power amplifier switching devices are used.

2. The household energy storage method with fully digital voltage and current double closed-loop control according to claim 1, characterized in that, The fully digital dual-loop control algorithm includes voltage outer loop control and current inner loop control. The voltage outer loop control takes the battery target voltage set by the user as a reference, and combines the real-time state of charge and health state of the battery to construct a dynamic voltage reference model. When facing a 100Ah energy storage battery module, an adaptive filtering algorithm is used to preprocess the actually collected voltage. When calculating the voltage deviation adjustment amount through the PID regulator, fuzzy control rules are introduced, and the PID parameters are dynamically adjusted according to the SOC and temperature information of the battery.

3. A household energy storage method with fully digital voltage and current double closed-loop control according to claim 2, characterized in that When the battery SOC is close to the full charge state, the proportional coefficient is automatically reduced to prevent voltage overshoot. When the battery temperature is too high, the integral coefficient is increased to accelerate the correction of the voltage deviation.

4. A household energy storage method with fully digital voltage and current double closed-loop control according to claim 3, characterized in that, In the current inner loop control, based on the current reference value output by the voltage outer loop, combined with the real-time change of the battery internal resistance and the charge and discharge power requirements, the current control strategy is further optimized. The predictive control algorithm is adopted. According to the historical current data and the current operating state of the battery, the current change trend in the next period of time is predicted, and the control signal is adjusted in advance to achieve the forward-looking control of the charge and discharge current. At the same time, a ripple suppression circuit is designed, and a current ripple compensation link is added to the control algorithm.

5. A household energy storage method with fully digital voltage and current double closed-loop control according to claim 4, characterized in that, In the current inner loop control, the specific operation is as follows: Based on the current reference value output by the voltage outer loop, the controller compares it with the actually collected current value. The charging current reference value given by the voltage outer loop is a certain value, and the actually measured current is a certain value. Through the PID regulator, the adjustment amount for this current deviation is calculated. Finally, this adjustment amount is converted into a control signal. After the signal is amplified, it acts on the power switch device IGBT. By controlling the on and off time and frequency of the power switch device IGBT, the charge and discharge current is adjusted to approach the target value.

6. A household energy storage method with fully digital voltage and current double closed-loop control according to claim 5, characterized in that, In the controller, when the battery is close to full charge, the internal resistance of the battery changes, which changes the change characteristics of the charging current. At this time, the controller can automatically identify this change, adjust the PID parameters, and make the current drop smoothly to avoid overcharging.

7. A household energy storage method with fully digital voltage and current double closed-loop control according to claim 6, characterized in that During the discharge process, if the load changes and the current demand changes, the controller responds by adjusting the control signal to stabilize the output current and ensure the stable operation of the system.

8. A household energy storage device with fully digital voltage and current double closed-loop control, characterized in that, It includes: At least one memory and at least one processor; The at least one memory is used to store machine-readable programs; The at least one processor is used to call the machine-readable program and execute the method according to any one of claims 1 to 7.