Distributed energy storage system emergency power supply method, device and system

Abstract

The invention provides an emergency power supply method, equipment and system for a distributed energy storage system, and the method comprises the steps: precisely calculating the state of charge of a battery through an ampere-hour integral method and a temperature compensation method, and achieving the quick and reliable switching control decision of the distributed energy storage system in a grid-connected standby mode, a grid-connected constant-power charging mode and an off-grid frequency conversion mode in combination with the operation state of a power grid. The complex sequential control process is simplified, and the emergency power supply stability and reliability of the distributed energy storage system are improved; the equipment comprises a controller, a distributed energy storage system, a grid-connected switch, a load switch and safety sub-equipment, an electrical topology circuit is simplified, debugging, operation and maintenance are convenient, safety protection functions are complete, and safety and reliability of emergency power supply operation of the distributed energy storage system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy storage, and in particular relates to an emergency power supply method, equipment and system for a distributed energy storage system. Background Art

[0002] In the scenario where the distributed energy storage system and the power grid are used for power supply, there is a key technical problem: how to achieve seamless switching and smooth transition between the energy storage system and the power grid when the power grid status changes frequently. Specifically, when the grid voltage is normal, the system needs to control the dual power supply switch so that the grid can supply power to the load. At the same time, the battery power must be monitored and charged through the grid-connected switch and converter when it is below the threshold. When the power grid is powered off, the system needs to quickly switch to the off-grid mode and be powered independently by the energy storage system. This process involves the coordinated control of multiple devices, including dual power supply switches, grid-connected switches, energy storage converters, etc. Especially in the case of frequent power outages and restoration of the power grid, how to ensure the stability and reliability of each switch and avoid power outages caused by untimely or improper switching is a complex control problem. In addition, how to ensure the stability of power quality indicators such as voltage and frequency during the switching process between different working modes is also a technical challenge that needs to be considered. The solution to this problem requires accurate state detection, fast decision-making algorithms and reliable execution mechanisms, which places high demands on the real-time performance and reliability of the control system. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies of the prior art, the present invention proposes a distributed energy storage system emergency power supply method, comprising:

[0004] Obtain battery parameters of the distributed energy storage system when the power grid is in normal operation;

[0005] Based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using an ampere-hour integration method and a temperature compensation method;

[0006] When the battery state of charge is not lower than a set state threshold, controlling the distributed energy storage system to be grid-connected and in standby mode;

[0007] When the battery state of charge is lower than the set state threshold, controlling the power grid to charge the distributed energy storage system with constant power until the power of the distributed energy storage system exceeds a preset usable threshold;

[0008] When the power grid cannot normally supply power to the load, the distributed energy storage system controls the battery state of charge to be not lower than the set state threshold to supply power to the load in an off-grid frequency conversion mode.

[0009] Preferably, controlling the distributed energy storage system to be grid-connected and in standby mode comprises:

[0010] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect, so that the distributed energy storage system is disconnected from the power grid;

[0011] The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

[0012] Preferably, the controlling the power grid to charge the distributed energy storage system with a constant power for grid connection includes:

[0013] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power for grid-connected charging;

[0014] At the same time, the load is controlled to be electrically connected to the power grid, and the load is controlled to be disconnected from the distributed energy storage system.

[0015] Preferably, the distributed energy storage system controlling the battery state of charge to be not less than the set state threshold supplies power to the load in the off-grid frequency conversion mode, including:

[0016] Controlling the distributed energy storage systems whose load and power exceed the available threshold to be disconnected from the power grid;

[0017] The load switch connected between the distributed energy storage system and the load is controlled to be closed, so that the distributed energy storage system with power exceeding the usable threshold supplies power to the load.

[0018] Preferably, the normal operating state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

[0019] Preferably, the state in which the power grid is unable to supply power to the load normally includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

[0020] Preferably, the method further includes: monitoring the voltage of the power grid and the amount of energy stored in the distributed energy storage system in real time through a human-machine interface, and recording the waveforms.

[0021] Based on the same inventive concept, the present invention also provides a distributed energy storage system emergency power supply device, the emergency power supply device is connected to an external power grid and a load respectively; the emergency power supply device comprises: a controller, and a distributed energy storage system, a grid-connected switch, a load switch and a safety sub-device which are all electrically connected to the controller;

[0022] The distributed energy storage system is connected to the power grid via the grid-connected switch in one path and connected to the load switch in another path; the load is switched and connected to the power grid and the load switch respectively via the safety sub-device;

[0023] The controller is used to obtain the battery parameters of the distributed energy storage system when the power grid is in a normal operating state; based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using the ampere-hour integration method and the temperature compensation method; when the battery state of charge is not lower than the set state threshold, the distributed energy storage system is controlled to be grid-connected and standby; when the battery state of charge is lower than the set state threshold, the power grid is controlled to charge the distributed energy storage system with grid-connected constant power until the power of the distributed energy storage system exceeds the preset usable threshold; when the power grid cannot supply power to the load normally, the distributed energy storage system with a battery state of charge not lower than the set state threshold is controlled to supply power to the load in an off-grid variable frequency mode.

[0024] Preferably, the distributed energy storage system includes an energy storage inverter, an energy storage battery connected to the DC end of the energy storage inverter, and a power detection module connected to the energy storage battery, and the grid-connected switch and the load switch are both connected to the AC end of the energy storage inverter.

[0025] Preferably, the safety sub-device comprises a dual-way automatic switching switch, and the load is connected to the power grid and the load switch respectively via two sub-switches of the dual-way automatic switching switch.

[0026] Preferably, the number of the loads is multiple, and the number of the two-way automatic switching switches is the same as the number of the loads and corresponds one to one; the multiple loads are connected in parallel to the power grid and the load switch via the two-way automatic switching switch.

[0027] Based on the same inventive concept, the present invention also provides a distributed energy storage system emergency power supply system, including: a parameter acquisition module, used to obtain battery parameters of the distributed energy storage system when the power grid is in a normal operating state;

[0028] A calculation module, used to calculate the battery state of charge of the distributed energy storage system based on the battery parameters by using an ampere-hour integration method and a temperature compensation method;

[0029] A first control module, used for controlling the distributed energy storage system to be grid-connected and in standby mode when the battery state of charge is not lower than a set state threshold;

[0030] A second control module is used to control the power grid to charge the distributed energy storage system with constant power when the battery state of charge is lower than the set state threshold, until the power of the distributed energy storage system exceeds a preset usable threshold;

[0031] The third control module is used to control the distributed energy storage system so that the battery state of charge is not lower than the set state threshold to supply power to the load in an off-grid frequency conversion mode when the power grid cannot supply power to the load normally.

[0032] Preferably, the first control module is specifically used for:

[0033] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect, so that the distributed energy storage system is disconnected from the power grid;

[0034] The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

[0035] Preferably, the second control module is specifically used for:

[0036] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power for grid-connected charging;

[0037] At the same time, the load is controlled to be electrically connected to the power grid, and the load is controlled to be disconnected from the distributed energy storage system.

[0038] Preferably, the third control module is specifically used for:

[0039] Controlling the distributed energy storage systems whose load and power exceed the available threshold to be disconnected from the power grid;

[0040] The load switch connected between the distributed energy storage system and the load is controlled to be closed, so that the distributed energy storage system with power exceeding the usable threshold supplies power to the load.

[0041] Preferably, the normal operating state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

[0042] Preferably, the state in which the power grid is unable to supply power to the load normally includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

[0043] Preferably, it also includes:

[0044] The monitoring module is used to monitor the voltage of the power grid and the energy storage capacity of the distributed energy storage system in real time through a human-machine interface, and to record the waveforms.

[0045] Based on the same inventive concept, the present invention also provides a computer device, including: one or more processors;

[0046] A memory for storing one or more programs;

[0047] When the one or more programs are executed by the one or more processors, the above-mentioned method for emergency power supply of a distributed energy storage system is implemented.

[0048] Based on the same inventive concept, the present invention also provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, an emergency power supply method for a distributed energy storage system as described above is implemented.

[0049] Compared with the closest prior art, the present invention has the following beneficial effects:

[0050] The present invention provides a distributed energy storage system emergency power supply method and system, comprising obtaining battery parameters of the distributed energy storage system when the power grid is in a normal operating state; based on the battery parameters, using the ampere-hour integration method and the temperature compensation method to calculate the battery state of charge of the distributed energy storage system; when the battery state of charge is not lower than a set state threshold, controlling the distributed energy storage system to be grid-connected and in standby mode; when the battery state of charge is lower than the set state threshold, controlling the power grid to charge the distributed energy storage system with grid-connected constant power until the power of the distributed energy storage system exceeds a preset usable threshold; when the power grid cannot supply power to the load normally, controlling the distributed energy storage system with a battery state of charge not lower than the set state threshold to supply power to the load in an off-grid variable frequency mode; the method and system are aimed at the green emergency reliable power supply demand of the load of important facilities, accurately detecting the battery state of charge of the distributed energy storage system through the ampere-hour integration method and the temperature compensation method, making a quick decision on the mode switching of the distributed energy storage system according to the battery state of charge and the power grid state, simplifying the complex sequential control process, and improving the stability and reliability of the emergency power supply of the distributed energy storage system.

[0051] The present invention also provides a distributed energy storage system emergency power supply device, including a controller, and a distributed energy storage system, a grid-connected switch, a load switch and a safety sub-device electrically connected to the controller; the distributed energy storage system is connected to the power grid via the grid-connected switch in one way and connected to the load switch in another way; the load is switched and connected to the power grid and the load switch respectively via the safety sub-device; by setting the grid-connected switch and the load switch, the device makes the overall electrical topology circuit of the device simple, is easy to debug and maintain, has complete safety protection functions, and improves the safety and reliability of the emergency power supply operation of the distributed energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of a flow chart of an emergency power supply method for a distributed energy storage system provided by the present invention;

[0053] Figure 2 A schematic diagram of the topological structure of emergency power supply equipment of a distributed energy storage system provided by the present invention;

[0054] Figure 3 A schematic diagram of the structure of a distributed energy storage system emergency power supply system provided by the present invention;

[0055] Figure 4 The present invention provides a schematic diagram of the structure of an electronic device. DETAILED DESCRIPTION

[0056] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0057] Embodiment 1:

[0058] The present invention provides a distributed energy storage system emergency power supply method, such as Figure 1 As shown, including:

[0059] S1. Obtaining battery parameters of the distributed energy storage system when the power grid is in normal operation;

[0060] S2. Based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using the ampere-hour integration method and the temperature compensation method;

[0061] S3. When the battery state of charge is not lower than the set state threshold, the distributed energy storage system is controlled to be grid-connected and in standby mode;

[0062] S4. When the battery state of charge is lower than the set state threshold, the power grid is controlled to charge the distributed energy storage system at a constant power until the power of the distributed energy storage system exceeds the preset usable threshold;

[0063] S5. When the power grid cannot supply power to the load normally, the distributed energy storage system that controls the battery state of charge to be not lower than the set state threshold supplies power to the load in the off-grid variable frequency mode.

[0064] Aiming at the green emergency reliable power supply demand of important facility loads, the present invention accurately detects the battery charge state of the distributed energy storage system through the ampere-hour integration method and the temperature compensation method, and makes a rapid decision on the mode switching of the distributed energy storage system according to the battery charge state and the power grid state, thereby simplifying the complex sequential control process and improving the stability and reliability of the emergency power supply of the distributed energy storage system.

[0065] This method includes three operating modes: emergency off-grid variable frequency power supply mode, grid-connected standby mode, and grid-connected constant power charging. It is suitable for emergency power supply scenarios for important loads by distributed energy storage systems. The system changes the operating mode by judging whether the grid-side voltage, i.e., the operating state, and the remaining power of the distributed energy storage battery, i.e., the battery charge state, exceed the threshold. When the load grid loses power, the distributed energy storage system works in the off-grid variable frequency mode to provide power to the load, thereby ensuring power supply reliability; when the grid has power and the distributed energy storage system battery is insufficient, it automatically charges and maintains the energy storage battery, so that the distributed energy storage system can automatically operate to provide power to important facilities in an unattended manner.

[0066] Considering the need to ensure a stable charging state during grid-connected constant power charging, the operating state of the grid is determined in the above S1;

[0067] In this embodiment, the normal operation state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

[0068] Specifically, S1 may include:

[0069] S101. Obtain the amplitude, frequency, phase and distortion rate of the grid voltage through a PT42 voltage sensor, wherein the voltage sensor has a range of 0 to 500 V, an accuracy of 0.5, and a sampling rate of 6.4 kHz;

[0070] S102, judging whether the obtained grid voltage amplitude is within the range of ±7% of 220V, whether the frequency is within the range of ±0.2Hz of 50Hz, whether the phase difference is less than 120°, and whether the distortion rate is less than 5%;

[0071] S103. If the voltage amplitude, frequency, phase difference and distortion rate of the power grid all meet the normal operation conditions of the power grid, then control Figure 2The dual power automatic transfer switch (ATS, Automatic Transfer Switch) as a safety sub-device is closed, so that the power grid supplies power to the load; specifically, the dual power automatic transfer switch ATS1 is controlled to close Q3 and open Q4, the dual power automatic transfer switch ATS2 is controlled to close Q5 and open Q6, the dual power automatic transfer switch ATS3 is controlled to close Q7 and open Q8, the dual power automatic transfer switch ATS4 is controlled to close Q9 and open Q10, and the dual power automatic transfer switch ATS5 is controlled to close Q11 and open Q12;

[0072] S104: Obtain the load power supply voltage, current and power, determine that the load power supply status is normal, and obtain the battery parameters of the distributed energy storage system.

[0073] Considering that the working mode switching of the distributed energy storage system is related to the battery charge state of the distributed energy storage system, a fast and accurate method is needed to obtain the battery charge state in real time. In the above S2, the battery charge state of the distributed energy storage system is accurately detected by the ampere-hour integration method and the temperature compensation method, so as to facilitate the rapid decision-making of the subsequent working mode switching;

[0074] In the above S2, it may include: using the ampere-hour integration method and the temperature compensation method to calculate the battery state of charge SOC (State of Charge) and health state SOH (State of Health) of the distributed energy storage system, obtaining the battery voltage, current and temperature of the distributed energy storage system as calculation input parameters, and judging whether the battery state of charge SOC is lower than a set state threshold. For example, the set state threshold is 30%;

[0075] Specifically, the battery state of charge SOC is calculated using the ampere-hour integration method and the temperature compensation method, including:

[0076] In the distributed energy storage system, a high-precision PT42 voltage sensor is installed to collect key battery data such as battery voltage, current, temperature, etc. of the distributed energy storage system in real time. Data filtering and denoising technologies such as Kalman filtering and wavelet transform are used to eliminate sensor noise and external interference, improve data quality, and perform time synchronization processing on the collected battery data to ensure the consistency of data from different sensors;

[0077] Then, the ampere-hour integration method is used to estimate the SOC of the distributed energy storage system battery by integrating the charge and discharge current of the battery. The specific steps are as follows:

[0078] Calculate the net charge of the battery over a period of time (current integral), that is, the integral of the current over time; convert the net charge into the change in SOC based on the rated capacity and actual charge and discharge efficiency of the battery; accumulate the change in SOC and combine it with the initial SOC of the battery to obtain the current SOC value;

[0079] Since the charging and discharging efficiency of the battery is greatly affected by temperature, a temperature compensation method is needed to improve the accuracy of SOC calculation. The specific steps include: establishing a relationship model between temperature and battery internal resistance, capacity and other parameters based on the temperature characteristics of the battery; when calculating SOC, correcting the SOC value obtained by the ampere-hour integration method based on the real-time collected battery temperature data.

[0080] Real-time monitoring of the battery SOC and adjustment of the charge and discharge strategy according to the SOC value can ensure that the battery operates within the optimal operating range and extend the battery life. This can achieve real-time and accurate calculation of the battery charge state of the distributed energy storage system, providing strong support for the operation management and maintenance of the system.

[0081] Considering the stability of the power grid when supplying power to the load, the distributed energy storage system does not need to be charged by the power grid at any time when it is not supplying power to the load. Therefore, when the battery state of charge is not less than 30% of the set state threshold, the distributed energy storage system is controlled to be grid-connected and standby. Specifically, in this embodiment, the distributed energy storage system is controlled to be grid-connected and standby, including:

[0082] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect the distributed energy storage system from the power grid;

[0083] The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

[0084] In this embodiment, when the battery state of charge is lower than the set state threshold by 30%, the power grid is controlled to charge the distributed energy storage system with constant power, including:

[0085] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power;

[0086] At the same time, the load is controlled to be electrically connected to the grid, and the load is disconnected from the distributed energy storage system.

[0087] Specifically, Figure 2 As shown, if the SOC is lower than 30%, the grid-connected switch Q1 is controlled to be closed, and the energy storage inverter in the system automatically operates in the grid-connected constant power charging mode, and the charging power is set to 50% of the rated power to charge the battery; the grid replenishes the battery until the battery power exceeds the preset usable threshold. For example, the usable threshold is the full charge threshold, that is, until the battery is fully charged.

[0088] Considering that when the battery state of charge is not lower than the set state threshold, the distributed energy storage system has the ability to supply power to the load in the off-grid state, whether the set state threshold is met is used as a condition for the distributed energy storage system to switch to the off-grid VF (Voltage Frequency, variable frequency) mode. Another off-grid variable frequency mode switching condition is that the grid is disconnected, that is, the grid is in an abnormal operating state. Therefore, in S5, when the first two conditions are met, the distributed energy storage system switches to the off-grid variable frequency mode to supply power to the load.

[0089] In this embodiment, the power grid is in an abnormal operating state when it is unable to supply power to the load normally. The abnormal operating state includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

[0090] Specifically, if the grid voltage amplitude exceeds the range of ±10% of 220V, or the frequency exceeds the range of ±0.5Hz of 50Hz, or the phase difference exceeds 180°, or the distortion rate exceeds 8%, and the abnormal duration exceeds 5 cycles, and occurs 3 times in a row, it is judged that the grid is out of power, that is, the grid is in an abnormal operating state; there is a certain error tolerance between the abnormal operating state of the grid and the aforementioned normal operating state, which is used to avoid frequent switching of the working state of the distributed energy storage system, affecting the stability of the system;

[0091] When it is determined that the grid is out of power, the system will switch from the grid-connected constant power charging state to the shutdown state, that is, the energy storage inverter of the distributed energy storage system is controlled to shut down, and then the grid-connected switch Q1 is disconnected. After confirming that the grid-connected switch Q1 is disconnected, the energy storage inverter will operate in the off-grid frequency conversion mode. At this time, the distributed energy storage system can be regarded as a constant voltage source, and the output voltage amplitude is set to 220V and the frequency is 50Hz. Subsequently, the distributed energy storage system is controlled to supply power to the load. Specifically, in this embodiment, the distributed energy storage system whose battery charge state is not lower than the set state threshold is controlled to supply power to the load in the off-grid frequency conversion mode, including:

[0092] Distributed energy storage systems that control loads and power that exceed the available threshold are disconnected from the grid;

[0093] The load switch Q2 connected between the distributed energy storage system and the load is controlled to be closed, and the distributed energy storage system whose power exceeds the usable threshold supplies power to the load.

[0094] Specifically, after the distributed energy storage system is started in the off-grid VF mode, if the output voltage meets the load power supply demand, Q3 of the dual power automatic switching switch ATS1 is opened and Q4 is closed, Q5 of the dual power automatic switching switch ATS2 is opened and Q6 is closed, Q7 of the dual power automatic switching switch ATS3 is opened and Q8 is closed, Q9 of the dual power automatic switching switch ATS4 is opened and Q10 is closed, Q11 of the dual power automatic switching switch ATS5 is opened and Q12 is closed, and the distributed energy storage system supplies power to the load. In the emergency power supply mode, the distributed energy storage system will continue to output until the power grid is re-energized, that is, the power grid returns to normal operation or the battery is discharged and the system shuts down.

[0095] In this embodiment, it also includes: real-time monitoring of the voltage of the power grid and the storage energy of the distributed energy storage system through a human-machine interface, and recording.

[0096] The aforementioned steps S1 to S5 are the sequential switching process of the three working modes of the distributed energy storage system. The subsequent control process refers to the following cycle:

[0097] S6. When the distributed energy storage system works in the off-grid VF mode to supply power to the load, if it is detected that the grid is powered again, the distributed energy storage system will shut down. After confirming that the system is shut down and there is no voltage output at the AC port of the converter, the Q1 switch is closed, Q3 of the dual power automatic switching switch ATS1 is closed and Q4 is separated, Q5 of the dual power automatic switching switch ATS2 is closed and Q6 is separated, Q7 of the dual power automatic switching switch ATS3 is closed and Q8 is separated, Q9 of the dual power automatic switching switch ATS4 is closed and Q10 is separated, Q11 of the dual power automatic switching switch ATS5 is closed and Q12 is separated, and the mode of powering the load by the grid is restored. At this time, according to step S2, if the battery voltage, that is, the battery state of charge SOC, is higher than the state threshold, the energy storage system works in the grid-connected standby mode. If the battery voltage is lower than the state threshold, the operation of step S4 is continued to allow the grid to replenish power for the battery of the distributed energy storage system;

[0098] S7. When the grid supplies power to the load and the distributed energy storage system works in the grid-connected standby mode, the grid is powered off. The sensor collects the voltage on the grid side of the load. According to the judgment rule of step S102, when the grid voltage amplitude exceeds the normal range, the system will switch from the grid-connected standby state to the shutdown state, and then separate the Q1 switch. After confirming that the grid-connected switch Q1 is separated, the energy storage inverter will work in the off-grid VF mode. At this time, the distributed energy storage system can be regarded as a constant voltage source;

[0099] S8. After the distributed energy storage system is started in the off-grid VF mode, if the output voltage meets the load power supply demand, Q3 of the dual power automatic switching switch ATS1 is opened and Q4 is closed, Q5 of the dual power automatic switching switch ATS2 is opened and Q6 is closed, Q7 of the dual power automatic switching switch ATS3 is opened and Q8 is closed, Q9 of the dual power automatic switching switch ATS4 is opened and Q10 is closed, Q11 of the dual power automatic switching switch ATS5 is opened and Q12 is closed, and the distributed energy storage system supplies power to the load. In the emergency power supply mode, the distributed energy storage system will continue to output until the grid is powered again or the battery is discharged and the system is shut down, that is, step S5 is repeated. If the grid side is powered again when the system is running in the off-grid VF mode, the system will operate according to step S6.

[0100] In summary, in response to the green emergency reliable power supply needs of important facilities, when the load grid side loses power, the distributed energy storage system works in the off-grid VF mode to provide power for the load, thereby ensuring the reliability of power supply. When the grid has power and the distributed energy storage system battery is insufficient, the energy storage battery is automatically charged and maintained; the complex sequential control process is simplified, and the stability and reliability of the distributed energy storage emergency power supply system are improved; the measurement and control protection performance is good, and the overcurrent risk caused by the closing of the grid-connected switch when the system works in the off-grid VF mode is avoided through software and hardware locking; in addition, automatic control can be achieved, which is more convenient, safer and more reliable than the emergency power supply device operated on site; and by setting up a friendly human-machine interface, all switch quantity, analog quantity, fault alarm status and other information are summarized in the monitoring background, which is convenient for intuitive monitoring of the system operation status and easy for on-site personnel to operate, so that once an emergency occurs, it can be handled quickly and promptly.

[0101] Embodiment 2:

[0102] Based on the same inventive concept, the present invention also provides a distributed energy storage system emergency power supply device, such as Figure 2 As shown, the emergency power supply equipment is connected to the external power grid and load respectively; the emergency power supply equipment includes: a controller, and a distributed energy storage system, a grid-connected switch, a load switch and a safety sub-device which are all electrically connected to the controller;

[0103] The distributed energy storage system is connected to the grid via a grid-connected switch on one side and to a load switch on the other side; the load is connected to the grid and the load switch via a safety sub-device;

[0104] The controller is used to obtain the battery parameters of the distributed energy storage system when the power grid is in normal operation; based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using the ampere-hour integration method and the temperature compensation method; when the battery state of charge is not lower than the set state threshold, the distributed energy storage system is controlled to be grid-connected and standby; when the battery state of charge is lower than the set state threshold, the power grid is controlled to charge the distributed energy storage system with constant power until the power of the distributed energy storage system exceeds the preset usable threshold; when the power grid cannot supply power to the load normally, the distributed energy storage system with a battery state of charge not lower than the set state threshold is controlled to supply power to the load in off-grid variable frequency mode.

[0105] The present invention provides a grid-connected switch and a load switch to simplify the overall electrical topology circuit of the equipment, facilitate debugging and maintenance, and provide complete safety protection functions, thereby improving the safety and reliability of emergency power supply operation of the distributed energy storage system.

[0106] In this embodiment, the distributed energy storage system includes an energy storage inverter, an energy storage battery connected to the DC end of the energy storage inverter, and a power detection module connected to the energy storage battery. The grid-connected switch and the load switch are both connected to the AC end of the energy storage inverter.

[0107] Specifically, Figure 2 As shown, the DC end of the energy storage converter AC / DC is connected to the energy storage battery, and the AC end is connected to the grid-connected switch Q1 and the load switch Q2.

[0108] In this embodiment, the safety sub-device includes a dual-way automatic switching switch, and the load is connected to the power grid and the load switch respectively through two sub-switches of the dual-way automatic switching switch.

[0109] like Figure 2 As shown, the ATS automatic switching switch as a safety sub-device and the safety-critical equipment control part are both arranged in the control cabinet. The dual power automatic switching switch ATS1 in the aforementioned embodiment corresponds to the ATS automatic switching switch in the control cabinet 1, and the subsequent switch numbers are numbered accordingly.

[0110] In this embodiment, there are multiple loads, and the number of dual-way automatic switching switches is the same as the number of loads and corresponds one to one; the multiple loads are connected in parallel to the power grid and the load switch via the dual-way automatic switching switch.

[0111] like Figure 2 As shown, the safety-critical devices 1-5 are the aforementioned multiple externally connected loads.

[0112] Embodiment 3:

[0113] Based on the same inventive concept, the present invention also provides a distributed energy storage system emergency power supply system, such as Figure 3As shown, it includes: a parameter acquisition module, which is used to obtain the battery parameters of the distributed energy storage system when the power grid is in a normal operating state;

[0114] A calculation module, used to calculate the battery state of charge of the distributed energy storage system based on battery parameters by using an ampere-hour integration method and a temperature compensation method;

[0115] The first control module is used to control the distributed energy storage system to be grid-connected and in standby mode when the battery state of charge is not lower than a set state threshold;

[0116] The second control module is used to control the power grid to charge the distributed energy storage system at a constant power when the battery state of charge is lower than a set state threshold, until the power of the distributed energy storage system exceeds a preset usable threshold;

[0117] The third control module is used to control the distributed energy storage system to ensure that the battery state of charge is not lower than a set state threshold to supply power to the load in an off-grid frequency conversion mode when the power grid cannot supply power to the load normally.

[0118] In this embodiment, the first control module is specifically used for:

[0119] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect the distributed energy storage system from the power grid;

[0120] The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

[0121] In this embodiment, the second control module is specifically used for:

[0122] Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power;

[0123] At the same time, the load is controlled to be electrically connected to the grid, and the load is disconnected from the distributed energy storage system.

[0124] In this embodiment, the third control module is specifically used for:

[0125] Distributed energy storage systems that control loads and power that exceed the available threshold are disconnected from the grid;

[0126] The load switch connected between the distributed energy storage system and the load is controlled to be closed, and the distributed energy storage system whose power exceeds the usable threshold supplies power to the load.

[0127] In this embodiment, the normal operation state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

[0128] In this embodiment, the state where the power grid cannot supply power to the load normally includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

[0129] In this embodiment, it also includes:

[0130] The monitoring module is used to monitor the voltage of the power grid and the energy storage capacity of the distributed energy storage system in real time through the human-machine interface, and to record the waveform.

[0131] Example 4

[0132] like Figure 4 As shown, the present invention also provides an electronic device, which may be a computer device, a single-chip device, an intelligent mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, the processor, and the transceiver component are connected via a bus; the memory may be used to store an execution program, and an exemplary execution program may include instructions; the processor is used to execute the instructions stored in the memory. The memory may also be used to store data, which may be called and / or modified when the instructions are executed.

[0133] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in a storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of a distributed energy storage system emergency power supply method in the above embodiment.

[0134] Example 5

[0135] Based on the same invention concept of a distributed energy storage system emergency power supply method, device and system, the present invention also provides a distributed energy storage system emergency power supply method, device and system readable storage medium, specifically an electronic device readable storage medium (Memory), the electronic device readable storage medium is a memory device in an electronic device, used to store programs and data. It can be understood that the storage medium here can include both built-in storage media in electronic devices and, of course, extended storage media supported by electronic devices. The storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more execution programs (including program codes). It should be noted that the storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor loads and executes one or more instructions stored in the storage medium, which can implement the steps of a distributed energy storage system emergency power supply method in the above embodiment.

[0136] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0138] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0139] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims of the present invention.

Claims

1. A distributed energy storage system emergency power supply method, characterized in that: include: Obtain battery parameters of the distributed energy storage system when the power grid is in normal operation; Based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using an ampere-hour integration method and a temperature compensation method; When the battery state of charge is not lower than a set state threshold, controlling the distributed energy storage system to be grid-connected and in standby mode; When the battery state of charge is lower than the set state threshold, controlling the power grid to charge the distributed energy storage system with constant power until the power of the distributed energy storage system exceeds a preset usable threshold; When the power grid cannot normally supply power to the load, the distributed energy storage system controls the battery state of charge to be not lower than the set state threshold to supply power to the load in an off-grid frequency conversion mode.

2. The method according to claim 1, characterized in that The controlling the distributed energy storage system to be grid-connected and in standby mode comprises: Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect, so that the distributed energy storage system is disconnected from the power grid; The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

3. The method according to claim 1, characterized in that The controlling the power grid to charge the distributed energy storage system with a constant power for grid connection includes: Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power for grid-connected charging; At the same time, the load is controlled to be electrically connected to the power grid, and the load is controlled to be disconnected from the distributed energy storage system.

4. The method according to claim 1, characterized in that The distributed energy storage system controlling the battery state of charge to be not lower than the set state threshold to supply power to the load in the off-grid frequency conversion mode includes: Controlling the distributed energy storage systems whose load and power exceed the available threshold to be disconnected from the power grid; The load switch connected between the distributed energy storage system and the load is controlled to be closed, so that the distributed energy storage system with power exceeding the usable threshold supplies power to the load.

5. The method according to claim 1, characterized in that The normal operating state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

6. The method according to claim 1, characterized in that The state in which the power grid cannot normally supply power to the load includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

7. The method according to claim 1, characterized in that Also includes: The voltage of the power grid and the energy storage capacity of the distributed energy storage system are monitored in real time through a human-machine interface, and waveforms are recorded.

8. A distributed energy storage system emergency power supply device, characterized in that: The emergency power supply equipment is connected to the external power grid and load respectively; the emergency power supply equipment includes: a controller, and a distributed energy storage system, a grid-connected switch, a load switch and a safety sub-device which are all electrically connected to the controller; The distributed energy storage system is connected to the power grid via the grid-connected switch in one path and connected to the load switch in another path; the load is switched and connected to the power grid and the load switch respectively via the safety sub-device; The controller is used to obtain the battery parameters of the distributed energy storage system when the power grid is in a normal operating state; based on the battery parameters, the battery state of charge of the distributed energy storage system is calculated using the ampere-hour integration method and the temperature compensation method; when the battery state of charge is not lower than the set state threshold, the distributed energy storage system is controlled to be grid-connected and standby; when the battery state of charge is lower than the set state threshold, the power grid is controlled to charge the distributed energy storage system with grid-connected constant power until the power of the distributed energy storage system exceeds the preset usable threshold; when the power grid cannot supply power to the load normally, the distributed energy storage system with a battery state of charge not lower than the set state threshold is controlled to supply power to the load in an off-grid variable frequency mode.

9. The device according to claim 8, characterized in that The distributed energy storage system includes an energy storage converter, an energy storage battery connected to the DC end of the energy storage converter, and a power detection module connected to the energy storage battery. The grid-connected switch and the load switch are both connected to the AC end of the energy storage converter.

10. The device according to claim 8, characterized in that The safety sub-device comprises a dual-way automatic switching switch, and the load is connected to the power grid and the load switch respectively via two sub-switches of the dual-way automatic switching switch.

11. The device according to claim 10, characterized in that The number of the loads is multiple, and the number of the two-way automatic switching switches is the same as that of the loads and corresponds one to one; the multiple loads are connected in parallel to the power grid and the load switch via the two-way automatic switching switch.

12. A distributed energy storage system emergency power supply system, characterized in that: include: A parameter acquisition module, used to obtain battery parameters of a distributed energy storage system when the power grid is in normal operation; A calculation module, used to calculate the battery state of charge of the distributed energy storage system based on the battery parameters by using an ampere-hour integration method and a temperature compensation method; A first control module, used for controlling the distributed energy storage system to be grid-connected and in standby mode when the battery state of charge is not lower than a set state threshold; A second control module is used to control the power grid to charge the distributed energy storage system with constant power when the battery state of charge is lower than the set state threshold, until the power of the distributed energy storage system exceeds a preset usable threshold; The third control module is used to control the distributed energy storage system so that the battery state of charge is not lower than the set state threshold to supply power to the load in an off-grid frequency conversion mode when the power grid cannot supply power to the load normally.

13. The system of claim 12, wherein: The first control module is specifically used for: Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to disconnect, so that the distributed energy storage system is disconnected from the power grid; The safety sub-device connected between the load and the power grid is controlled to be closed, and the safety sub-device connected between the load and the distributed energy storage system is controlled to be disconnected, so that the load is electrically connected to the power grid.

14. The system of claim 12, wherein: The second control module is specifically used for: Controlling the grid-connected switch connected between the distributed energy storage system and the power grid to close, so that the distributed energy storage system is electrically connected to the power grid, and the power grid charges the distributed energy storage system with a constant power for grid-connected charging; At the same time, the load is controlled to be electrically connected to the power grid, and the load is controlled to be disconnected from the distributed energy storage system.

15. The system of claim 12, wherein: The third control module is specifically used for: Controlling the distributed energy storage systems whose load and power exceed the available threshold to be disconnected from the power grid; The load switch connected between the distributed energy storage system and the load is controlled to be closed, so that the distributed energy storage system with power exceeding the usable threshold supplies power to the load.

16. The system of claim 12, wherein: The normal operating state of the power grid includes: the voltage amplitude of the power grid is within the range of ±7% of 220V, the voltage frequency of the power grid is within the range of ±0.2Hz of 50Hz, the voltage phase difference of the power grid is less than 120°, and the voltage distortion rate of the power grid is less than 5%.

17. The system of claim 12, wherein: The state in which the power grid cannot normally supply power to the load includes: the voltage amplitude of the power grid exceeds the range of ±10% of 220V, or the voltage frequency of the power grid exceeds the range of ±0.5Hz of 50Hz, or the voltage phase difference of the power grid exceeds 180°, or the voltage distortion rate of the power grid exceeds 8%.

18. The system of claim 12, wherein: Also includes: The monitoring module is used to monitor the voltage of the power grid and the energy storage capacity of the distributed energy storage system in real time through a human-machine interface, and to record the waveforms.

19. A readable storage medium, characterized in that: An execution program is stored thereon, and when the execution program is executed, a distributed energy storage system emergency power supply method as described in any one of claims 1 to 7 is implemented.

Images