High-safety energy storage system suitable for zero-carbon power supply station and control method

Abstract

The embodiment of the invention provides a high-safety energy storage system suitable for a zero-carbon power supply station and a control method. The system comprises a direct-current bus, energy storage equipment, an energy storage converter and a protection device. The energy storage converter can collect bus voltage and protection current of an energy storage branch in real time through an electric energy sensor. When the bus voltage is smaller than or equal to the lower limit voltage, the energy storage converter is controlled to enter a maximum current discharge state; when the bus voltage is equal to the standard working voltage, the energy storage converter is controlled to be kept in a standby state; and when the bus voltage is greater than or equal to the upper limit voltage, controlling the energy storage converter to enter a maximum current charging state. The system can realize bidirectional flow of energy between the energy storage equipment and the direct current bus, so that the energy storage equipment can be flexibly charged and discharged according to the voltage of the direct current bus, the voltage fluctuation of the direct current bus is relieved, and the overall operation performance of the system is improved.

Description

Technical Field

[0001] This application relates to the technical field of DC system power distribution and protection, and particularly to a high - security energy storage system and control method applicable to a zero - carbon power supply station. Background Art

[0002] A zero - carbon power supply station refers to a power system supply service center integrating new energy power generation, energy storage, charging piles, and power - consuming facilities. By applying new energy power generation methods such as photovoltaic power generation and wind power generation, all - clean energy supply and zero - carbon operation within the power supply station can be achieved. Due to the distribution characteristics of new energy such as light energy and wind energy, it is necessary to make full use of new energy in a large distribution area. Therefore, the new energy power generation method needs to adopt distributed power generation, that is, the power generation equipment needs to be distributed in multiple areas.

[0003] In order to adapt to the new energy power generation method, a zero - carbon power supply station can adopt a DC system to accept distributed power generation. Among them, the DC system is a power system centered on direct current. Through high - efficiency and low - loss direct current, the direct current generated by new energy power generation is directly used for DC loads within the power supply station, and an energy storage system is used for energy storage and regulation to achieve efficient utilization and stable supply of energy.

[0004] However, the DC system has problems of low safety and discontinuous current during the charging and discharging process, resulting in limited application scenarios of the DC system in the zero - carbon power supply station. When safety incidents or current discontinuity problems occur, the safety and stability of the entire power supply station will be affected. Summary of the Invention

[0005] In view of this, the embodiments of this application provide a high - security energy storage system and control method applicable to a zero - carbon power supply station to solve the problem of discontinuous current during the charging and discharging process of the DC system.

[0006] According to one aspect of this application, a high - security energy storage system applicable to a zero - carbon power supply station is provided. The system includes: a DC bus, an energy storage device, an energy storage converter, and a protection device;

[0007] Among them, the energy storage device is connected to the DC bus through the energy storage converter to form an energy storage branch; the protection device includes a circuit breaker, an electric energy sensor, and a controller; the circuit breaker is arranged on the energy storage branch, and the circuit breaker is located between the DC bus and the energy storage converter; the electric energy sensor is arranged on the DC bus and / or the energy storage branch; the electric energy sensor is connected to the controller;

[0008] The controller is configured to:

[0009] Obtain the bus voltage collected by the power sensor and preset energy storage control parameters, where the energy storage control parameters include a standard operating voltage and a fluctuation range; the standard operating voltage is within the fluctuation range; the fluctuation range includes an upper limit voltage and a lower limit voltage;

[0010] If the bus voltage is less than or equal to the lower limit voltage, send a boost command to the energy storage converter, and the boost command is used to make the energy storage converter in the maximum current discharge state;

[0011] If the bus voltage is greater than or equal to the upper limit voltage, send a buck command to the energy storage converter, and the buck command is used to make the energy storage converter in the maximum current charge state;

[0012] If the bus voltage is equal to the standard operating voltage, send a standby command to the energy storage converter, and the standby command is used to make the energy storage converter stop discharging or charging.

[0013] Optionally, the energy storage converter includes a boost conversion branch and a buck conversion branch, the boost conversion branch and the buck conversion branch are arranged in parallel, and are alternately turned on based on the boost command or the buck command; the conduction signals of the power tubes on the boost conversion branch and the buck conversion branch are staggered by 180°.

[0014] Optionally, the energy storage converter includes: a first wire, a second wire, a third wire, a fourth wire, a first power tube, a second power tube, a first diode, and a second diode;

[0015] The first wire is connected to the positive electrode of the energy storage device; the second wire is connected to the negative electrode of the energy storage device; the third wire is connected to the positive electrode of the DC bus; the fourth wire is connected to the negative electrode of the DC bus; the second wire is also connected to the fourth wire;

[0016] The collector of the first power tube is connected to the negative electrode of the first diode; the emitter of the first power tube is connected to the positive electrode of the first diode; the collector of the second power tube is connected to the negative electrode of the second diode; the emitter of the second power tube is connected to the positive electrode of the second diode;

[0017] The first diode and the second diode are connected in series between the third wire and the fourth wire to form a first branch; the first wire is connected to the first connection point of the first branch, and the first connection point is located between the first diode and the second diode.

[0018] Optionally, the energy storage converter further includes: a third power tube, a fourth power tube, a third diode, and a fourth diode;

[0019] The collector of the third power transistor is connected to the negative electrode of the third diode; the emitter of the third power transistor is connected to the positive electrode of the third diode; the collector of the fourth power transistor is connected to the negative electrode of the fourth diode; the emitter of the fourth power transistor is connected to the positive electrode of the fourth diode;

[0020] The third diode and the fourth diode are connected in series between the third wire and the fourth wire to form a second branch; the first wire is connected to the second connection point of the second branch, and the second connection point is located between the third diode and the fourth diode.

[0021] Optionally, the energy storage converter is configured to:

[0022] When receiving the boost instruction, the second power transistor and the fourth power transistor generate switching actions, and freewheel through the first diode and the third diode;

[0023] When receiving the buck instruction, the first power transistor and the third power transistor generate switching actions, and freewheel through the second diode and the fourth diode.

[0024] Optionally, the energy storage converter further includes: a first inductor and a second inductor;

[0025] The first inductor is connected between the first wire and the first connection point;

[0026] The second inductor is connected between the first wire and the second connection point.

[0027] Optionally, the energy storage converter further includes: a first capacitor and a second capacitor;

[0028] One end of the first capacitor is connected to the first wire, and the other end of the first capacitor is connected to the second wire;

[0029] One end of the second capacitor is connected to the third wire, and the other end of the second capacitor is connected to the fourth wire.

[0030] Optionally, the protection device further includes a first transmitter; the electrical energy sensor includes a voltage sensor;

[0031] The voltage sensor is disposed on the DC bus, and the voltage sensor is connected to the controller; the voltage sensor is configured to sense a first electrical signal according to the voltage of the DC bus;

[0032] The first transmitter is arranged between the voltage sensor and the controller, and the first transmitter is configured to convert a first electrical signal sensed by the voltage sensor into an electrical signal acceptable to the controller, so as to obtain the bus voltage.

[0033] Optionally, the protection device further includes a second transmitter; the electrical energy sensor further includes a current sensor;

[0034] The current sensor is arranged between the DC bus and the energy storage converter, the current sensor is connected to the controller, and the current sensor is configured to sense a second electrical signal according to the current on the energy storage branch;

[0035] The second transmitter is arranged between the current sensor and the controller, and the second transmitter is configured to convert a second electrical signal sensed by the current sensor into an electrical signal acceptable to the controller, so as to obtain the protection current;

[0036] The controller is further configured to:

[0037] Obtain the protection current and a preset current judgment interval;

[0038] If the protection current is not within the current judgment interval, query the target energy storage branch to which the current sensor belongs;

[0039] Send a disconnection instruction to the circuit breaker on the target energy storage branch.

[0040] According to another aspect of the present application, there is provided an energy storage control method, which is applied to the high-security energy storage system suitable for a zero-carbon power supply station, and the method includes:

[0041] Obtain the bus voltage collected by the electrical energy sensor and preset energy storage control parameters, where the energy storage control parameters include a standard operating voltage and a fluctuation range; the standard operating voltage is within the fluctuation range; the fluctuation range includes an upper limit voltage and a lower limit voltage;

[0042] If the bus voltage is less than or equal to the lower limit voltage, send a boost instruction to the energy storage converter, and the boost instruction is used to make the energy storage converter in a maximum current discharge state;

[0043] If the bus voltage is greater than or equal to the upper limit voltage, send a buck instruction to the energy storage converter, and the buck instruction is used to make the energy storage converter in a maximum current charge state;

[0044] If the bus voltage is equal to the standard operating voltage, send a standby instruction to the energy storage converter, and the standby instruction is used to make the energy storage converter stop discharging or charging.

[0045] According to another aspect of the present application, there is provided a storage medium, on which a computer program is stored, and when the program is executed by a processor, the above-mentioned energy storage control method is implemented.

[0046] By means of the above technical solution, the embodiments of the present application provide a high-security energy storage system and control method applicable to a zero-carbon power supply station. The system includes: a DC bus, an energy storage device, an energy storage converter, and a protection device. Among them, the energy storage converter can collect the bus voltage and the protection current of the energy storage branch in real time through an electric energy sensor. When the bus voltage is less than or equal to the lower limit voltage, the energy storage converter is controlled to enter the maximum current discharge state; when the bus voltage is equal to the standard operating voltage, the energy storage converter is controlled to maintain the standby state; when the bus voltage is greater than or equal to the upper limit voltage, the energy storage converter is controlled to enter the maximum current charging state. The system can realize the bidirectional flow of energy between the energy storage device and the DC bus, enabling the energy storage device to perform flexible charging and discharging according to the DC bus voltage, alleviating the DC bus voltage fluctuation, and improving the overall operation performance of the system.

[0047] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically exemplified below. Description of the Drawings

[0048] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0049] Figure 1 is a schematic structural diagram of a high-security energy storage system applicable to a zero-carbon power supply station provided by an embodiment of the present application;

[0050] Figure 2 is a schematic structural diagram of an energy storage converter provided by an embodiment of the present application;

[0051] Figure 3 is a schematic flow diagram of an energy storage system control method provided by an embodiment of the present application;

[0052] Figure 4 is a schematic diagram of the discharging process of an energy storage device provided by an embodiment of the present application;

[0053] Figure 5 is a schematic diagram of the charging process of an energy storage device provided by an embodiment of the present application;

[0054] Figure 6 is a schematic diagram of the flexible charging and discharging effect provided by an embodiment of the present application;

[0055] Figure 7 Structural schematic diagram of the protection device provided by the embodiment of the present application;

[0056] Figure 8 Schematic diagram of the fault protection process provided by the embodiment of the present application. Detailed implementation manners

[0057] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0058] In order to alleviate the problem of discontinuous current during the charge and discharge process of the DC system, a high - safety energy storage system applicable to a zero - carbon power supply station is provided in this embodiment, as Figure 1 shown. The system includes: a DC bus, an energy storage device, an energy storage converter, and a protection device.

[0059] Among them, the energy storage device is used to convert electrical energy into other forms of energy to store electrical energy. In some embodiments, the energy storage device can convert electrical energy into chemical energy to achieve electrical energy storage. That is, the energy storage device includes an energy storage battery or an energy storage battery pack. For example, the energy storage device can include one or a combination of lithium - ion batteries, sodium - ion batteries, all - vanadium redox flow batteries, lead - carbon batteries. The energy storage device can improve the new - energy consumption capacity of the power supply station, enhance the stability and power supply reliability of the power grid, and contribute to promoting the zero - carbonization and intelligentization of the power supply station.

[0060] In addition to the energy storage battery, the energy storage device can also include functional devices for assisting charge and discharge. For example, battery management devices, charge - discharge testers, power routers, auxiliary channel devices, inverters, etc. By setting functional devices for assisting charge and discharge, the operation efficiency and reliability of the energy storage system can be improved, and the stable power supply of the power supply station can be guaranteed.

[0061] It should be noted that the power supply station can also store electrical energy in other ways, that is, the energy storage device can also store the electrical energy generated during the peak period of new - energy power generation based on physical energy storage, electromagnetic energy storage, etc. In some embodiments of the present application, the system is described by taking an energy storage battery or an energy storage battery pack as an example of the energy storage device. It should be understood that other types of energy storage devices associated by those skilled in the art based on the energy storage battery also belong to the protection scope of the present application.

[0062] The energy storage device is connected to the DC bus through an energy storage converter to form an energy storage branch. Among them, the energy storage converter is used to switch different connection modes under different DC - bus power - energy states to adapt to the charge - discharge modes of the energy storage device.

[0063] To meet the power storage requirements of the power supply station, multiple energy storage devices can be connected to a DC bus. The multiple energy storage devices can be connected in parallel with each other and are respectively connected to the DC bus through multiple energy storage converters to form multiple energy storage branches.

[0064] For this reason, in some embodiments, the energy storage converter includes a buck (step-down) branch and a boost (step-up) branch. The buck branch and the boost branch are arranged in parallel and conduct alternately based on a boost instruction or a buck instruction. Moreover, the conduction signals of the power tubes on the buck branch and the boost branch are staggered by 180°. The energy storage converter adopts a two-phase Buck-Boost parallel structure and an interleaved conduction control method, which can make the output ripple current frequency twice the switching frequency, thereby reducing the value and volume of the filter capacitor on the battery side, enabling the battery to charge and discharge efficiently, and the stable protection time of the bus voltage can reach the microsecond level.

[0065] As Figure 2 shown, in some embodiments, the energy storage converter includes: a first wire Lbat+, a second wire Lbat-, a third wire Lbus+, a fourth wire Lbus-, a first power tube S1, a second power tube S2, a first diode D1, and a second diode D2. Among them, the first wire Lbat+ is connected to the positive electrode of the energy storage device; the second wire Lbat- is connected to the negative electrode of the energy storage device; the third wire Lbus+ is connected to the positive electrode of the DC bus; the fourth wire Lbus- is connected to the negative electrode of the DC bus; the second wire Lbat- is also connected to the fourth wire Lbus-.

[0066] The first power tube S1 and the second power tube S2 can be switching tubes such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs), which are used to control the on and off of the corresponding current according to an input signal (or instruction). Therefore, both the first power tube S1 and the second power tube S2 include a gate, a collector, and an emitter. Among them, the gate is used to receive a control signal (or a control instruction), thereby controlling the connection state of the collector and the emitter according to the control signal received by the gate. The first diode D1 and the second diode D2 are diode devices used to achieve unidirectional flow. Both the first diode D1 and the second diode D2 can include a positive electrode and a negative electrode. In the circuit, current can flow from the positive electrode of the diode to the negative electrode, but cannot flow from the negative electrode of the diode to the positive electrode.

[0067] Therefore, the collector of the first power transistor S1 is connected to the negative electrode of the first diode D1; the emitter of the first power transistor S1 is connected to the positive electrode of the first diode D1; the collector of the second power transistor S2 is connected to the negative electrode of the second diode D2; the emitter of the second power transistor S2 is connected to the positive electrode of the second diode D2.

[0068] The first diode D1 and the second diode D2 are connected in series between the third wire Lbus+ and the fourth wire Lbus- to form a first branch; the first wire Lbat+ is connected to a first connection point of the first branch, and the first connection point is located between the first diode D1 and the second diode D2.

[0069] In order to better transfer electric energy, in some embodiments, the energy storage converter further includes: a third power transistor S3, a fourth power transistor S4, a third diode D3, and a fourth diode D4. The third power transistor S3 and the fourth power transistor S4 are the same as the first power transistor S1 and the second power transistor S2 described in the above embodiments, and are both specific types of switching transistor devices, that is, the third power transistor S3 and the fourth power transistor S4 also include a gate, a collector, and an emitter. Similarly, similar to the first diode D1 and the second diode D2, the third diode D3 and the fourth diode D4 also include a positive electrode and a negative electrode.

[0070] Therefore, the collector of the third power transistor S3 is connected to the negative electrode of the third diode D3; the emitter of the third power transistor S3 is connected to the positive electrode of the third diode D3; the collector of the fourth power transistor S4 is connected to the negative electrode of the fourth diode D4; the emitter of the fourth power transistor S4 is connected to the positive electrode of the fourth diode D4.

[0071] The third diode D3 and the fourth diode D4 are connected in series between the third wire Lbus+ and the fourth wire Lbus- to form a second branch; the first wire Lbat+ is connected to a second connection point of the second branch, and the second connection point is located between the third diode D3 and the fourth diode D4.

[0072] In some embodiments, the energy storage converter further includes: a first inductor L1 and a second inductor L2. The first inductor L1 is connected between the first wire Lbat+ and the first connection point P1; the second inductor L2 is connected between the first wire Lbat+ and the second connection point P2. Since the energy storage converter uses a two-phase parallel interleaved Buck-Boost bi-directional power circuit, the conduction signals of the switching devices in the two module circuits are staggered by 180°. For each single path of the dual Boost circuits with a switching frequency of f, in the case of interleaved parallel connection, the total switching frequency will be 2f. This means that the current harmonic frequency in the inductor will also be 2f. That is, the frequency of the total harmonic current of the inductor can be doubled. This frequency doubling effect can reduce the current ripple, reduce the inductor volume, and increase the power density of the circuit. And the ripple rate decreases and is related to the duty cycle. When the duty cycle increases, the conduction time of the switching tube increases, and the energy storage time of the inductor also increases accordingly. This results in more energy released by the inductor when the switching tube is turned off, which may increase the current ripple.

[0073] In some embodiments, the energy storage converter further includes: a first capacitor C1 and a second capacitor C2. One end of the first capacitor C1 is connected to the first wire Lbat+, and the other end of the first capacitor C1 is connected to the second wire Lbat-; one end of the second capacitor C2 is connected to the third wire Lbus+, and the other end of the second capacitor C2 is connected to the fourth wire Lbus-. The first capacitor C1 and the second capacitor C2 can serve as buffer capacitors of the energy storage converter, which can smooth the input and output voltages and reduce voltage fluctuations.

[0074] To achieve the charging and discharging functions, when the energy storage converter receives a boost command, the boost command can control the second power transistor S2 and the fourth power transistor S4 to generate switching actions, so that the second power transistor S2 and the fourth power transistor S4 are closed, and the first power transistor S1 and the third power transistor S3 are turned off. At this time, the energy storage converter switches to the boost conversion (Boost) branch to work, and continues to flow through the first diode D1 and the third diode D3. The current flows from the energy storage device (Ubat) side to the DC bus (Ubus) side, realizing the discharge of the energy storage device to the DC bus to increase the bus voltage of the DC bus.

[0075] Similarly, when the energy storage converter receives a buck command, the buck command can control the first power transistor S1 and the third power transistor S3 to generate switching actions, so that the first power transistor S1 and the third power transistor S3 are closed, and the second power transistor S2 and the fourth power transistor S4 are turned off. At this time, the energy storage converter switches to the buck conversion (Buck) branch to work, and continues to flow through the second diode D2 and the fourth diode D4. The current flows from the DC bus (Ubus) side to the energy storage device (Ubat) side, realizing the charging of the DC bus to the energy storage device to reduce the bus voltage of the DC bus.

[0076] It can be seen that through the boost branch and buck branch set by the energy storage converter, bidirectional power flow can be achieved in response to specific control instructions.

[0077] The protection device is used to monitor the power states of the DC bus and each energy storage branch, and control the on-off states of the corresponding lines according to the monitoring results, so as to control the circuit breaker to disconnect when a fault occurs in the corresponding line, clear the fault and reduce the impact of the corresponding line fault on the entire DC system. For example, the protection device can have multiple protection functions, including but not limited to overcurrent quick-break protection for multiple branches, overcurrent protection with low-voltage blocking for multiple branches, low (under) voltage protection, overvoltage protection, etc.

[0078] To implement the protection function, the protection device can include a circuit breaker, an electrical energy sensor, and a controller. Among them, the circuit breaker is used to control the on-off state of the corresponding line. For the energy storage branch, the circuit breaker can be set on the energy storage branch, and the circuit breaker is located between the DC bus and the energy storage converter. For example, the circuit breaker QF1 is set on the energy storage branch where the energy storage converter ESC-1 and the energy storage device ESE-1 are located; the circuit breaker QFN is set on the energy storage branch where the energy storage converter ESC-N and the energy storage device ESE-N are located. When a short circuit, overload or other faults occur in the energy storage branch, the circuit breaker can quickly cut off the connection state of the corresponding energy storage branch to prevent the accident from expanding. The circuit breaker can include a high-voltage circuit breaker and a low-voltage circuit breaker, which are respectively used for fault protection of high-voltage lines and low-voltage lines.

[0079] The protection device can have functions such as current, voltage, and power measurement. Therefore, the protection device can include an electrical energy sensor. The electrical energy sensor can collect information such as voltage, current, and power at the arranged position, and the collected information can be used to judge whether a fault occurs in the corresponding line and whether the fault is eliminated after performing the fault protection function. The protection device can set various fixed value parameters, then sample the voltage or current signal, and then compare it with the set value. If the voltage or current signal does not satisfy a specific relationship with the set value, such as the voltage or current is greater than the set value, it will control the circuit breakers QF1 - QFN to disconnect.

[0080] For example, for the branch overcurrent instantaneous protection, the current signal of the energy storage branch can be detected, and it is determined whether the current is greater than the set overcurrent value. If the current is greater than the set overcurrent value, the circuit breaker is controlled to disconnect the corresponding energy storage branch. For the branch overcurrent protection with low-voltage blocking, the voltage signal and the current signal can be detected, and it is determined whether the voltage is less than the set low-voltage value and whether the current is greater than the set overcurrent value. If the voltage is less than the set low-voltage value and the current is greater than the set overcurrent value, the circuit breaker is controlled to disconnect. For the low (under) voltage protection, the voltage signal can be detected, and it is determined whether the voltage value is less than the set low (under) voltage value. If the voltage value is less than the set low (under) voltage value, the circuit breaker is controlled to disconnect. For the overvoltage protection, the voltage can be detected, and it is determined whether the voltage value is greater than the set overvoltage protection threshold. If the voltage value is greater than the set overvoltage protection threshold, the circuit breaker is controlled to disconnect.

[0081] The electrical energy sensor can be arranged on the DC bus and / or the energy storage branch. According to the type of information detected and the detection principle of the sensor, the electrical energy sensor can be arranged on the DC bus or the energy storage branch in different ways.

[0082] In some embodiments, the electrical energy sensor can include a current sensor and a voltage sensor. The current sensor can sense an electrical signal according to the current condition of the corresponding line for detecting the current information of the corresponding line. The voltage sensor can sense an electrical signal according to the voltage condition of the corresponding line for detecting the voltage information of the corresponding line.

[0083] For example, the current sensor can be one or a combination of sensors such as a resistance shunt, a current transformer, a Hall effect device, etc. When the current sensor is a resistance shunt, the current sensor can be connected in series in the corresponding line. Then, based on Ohm's law, when current passes through a very small resistance (shunt), a voltage drop will be generated across the resistance. The current information of the corresponding line can be calculated by measuring this voltage drop and according to Ohm's law.

[0084] Similarly, the voltage sensor can be one or a combination of sensors such as a resistance voltage divider, an electromagnetic voltage transformer, a capacitive voltage transformer, a Hall voltage sensor, etc. When the voltage sensor is a Hall voltage sensor, the voltage sensor can limit the current to the milliampere level through an external or internal resistor. After this current passes through a multi-turn winding, the magnetic field generated by the primary current is detected by the Hall element in the air gap and induces a corresponding electromotive force. Then, after circuit adjustment, it is fed back to the compensation coil for compensation to obtain the voltage information of the corresponding line.

[0085] The information such as voltage, current, and power detected by the power sensor can be sent to the controller to determine whether there is a fault in the corresponding circuit through the controller. To this end, the power sensor can be connected to the controller. Among them, the controller can be a Central Processing Unit (CPU), a single-chip microcomputer, a Micro-Controller Unit, etc.

[0086] In some embodiments, to facilitate the controller to judge the working state according to the bus voltage, when the power sensor includes a voltage sensor, the protection device may further include a first transmitter. The voltage sensor is arranged on the DC bus, and the voltage sensor is connected to the controller; the voltage sensor is configured to induce a first electrical signal according to the voltage of the DC bus. The first transmitter is arranged between the voltage sensor and the controller, and the first transmitter is configured to convert the first electrical signal induced by the voltage sensor into an electrical signal that the controller can receive, so as to obtain the bus voltage. For example, the first transmitter can convert the collected voltage signal into a small digital voltage that the controller can receive and read after processing such as interval mapping and analog-to-digital conversion.

[0087] When performing the control function, the application program related to the control function can be pre-configured, and then the controller can implement the control function by executing the application program. In some embodiments, to simplify the structure of the energy storage system, on the premise that the control ability of the controller meets the requirements, while implementing the protection function, the controller can also be used to control the energy storage converter, that is, the controller can send different control instructions to the energy storage converter to control the energy storage converter to switch the working state.

[0088] Among them, the working states of the energy storage converter can include a discharging state, a standby state, and a charging state. When the energy storage converter is in the discharging state, the energy storage device can transfer electric energy to the DC bus to compensate for the DC bus voltage. When the energy storage converter is in the standby state, the energy storage device and the DC bus can be kept open and no longer transfer electric energy to each other. When the energy storage converter is in the charging state, the DC bus can transfer electric energy to the energy storage device to store the excess electric energy in the DC bus into the energy storage device and reduce the output voltage of the DC bus.

[0089] Therefore, as Figure 3 shown, the controller is configured to:

[0090] S101. Obtain the bus voltage collected by the power sensor and the preset energy storage control parameters.

[0091] Among them, the energy storage control parameters include the standard operating voltage U1 and the fluctuation range [U2, U3]. The fluctuation range [U2, U3] includes the upper limit voltage U3 and the lower limit voltage U2. The upper limit voltage U3 and the lower limit voltage U2 respectively refer to the highest voltage value and the lowest voltage value allowed for the DC bus during normal operation.

[0092] In different seasons and different time periods, due to different power generation amounts, the DC bus voltage of the power supply station will be maintained within a fluctuation range. The fluctuation range is the range within which the DC bus voltage is allowed to change under normal operating conditions, that is, the range from the lower limit voltage to the upper limit voltage. According to the designed power supply parameters of the power supply station, the upper limit voltage and the lower limit voltage of the fluctuation range can be dynamically set to ensure that the equipment in the power supply station can operate within a stable voltage range, improving the reliability and stability of the system.

[0093] The upper limit voltage, as the highest value that the DC bus is allowed to reach under normal operating conditions, can be used to limit the highest voltage of the DC bus, prevent equipment damage caused by excessive voltage, and ensure that the equipment operates within a safe voltage range. For example, in some zero-carbon power supply stations, the upper limit voltage of the DC bus may be set to 900V.

[0094] The lower limit voltage, as the lowest value that the DC bus is allowed to reach under normal operating conditions, can prevent the equipment from malfunctioning due to too low voltage and ensure that the equipment operates within an effective voltage range. For example, in some zero-carbon power supply station projects, the lower limit voltage of the DC bus may be set to 500V. Based on this, the fluctuation range of the power supply station can be [500V, 900V].

[0095] To meet the designed power supply requirements, the energy storage system can also be provided with a standard operating voltage U1. The standard operating voltage U1 is a voltage standard specified for the nominal voltage when the power supply station supplies power outward. That is, the standard operating voltage U1 is within the fluctuation range [U2, U3]. The standard operating voltage U1 can be set according to the rated voltage of the electrical equipment driven by the power supply station. For example, the standard operating voltage U1 can be set to 750V according to the rated voltage of the electrical equipment. The standard operating voltage U1 can also be comprehensively set according to factors such as the number, deployment method, time, and season of the power generation equipment in the power supply station.

[0096] After the power sensor senses an electrical signal based on the voltage of the DC bus, it can convert the electrical signal into bus voltage data and send the bus voltage to the controller. After receiving the bus voltage, the controller obtains the preset energy storage control parameters and reads the standard operating voltage U1 and the fluctuation range [U2, U3] from the preset energy storage control parameters. Then, it compares the received bus voltage with the standard operating voltage U1, the lower limit voltage U2, and the upper limit voltage U3.

[0097] S102. If the bus voltage is less than or equal to the lower limit voltage, send a boost command to the energy storage converter.

[0098] By comparing the bus voltage with the lower limit voltage U2, when the bus voltage U is less than or equal to the lower limit voltage U2, it indicates that the current bus voltage is too low and the power generation is insufficient. Therefore, the energy storage device can be used to compensate the bus voltage. Thus, the controller can generate a boost command and send the boost command to the energy storage converter, so that the energy storage converter switches to work through the boost conversion (Boost) branch. At this time, the energy storage device can transmit electric energy to the DC bus to compensate the bus voltage of the DC bus.

[0099] Among them, the boost command is used to make the energy storage converter in the maximum current discharge state. In some embodiments, the boost command is a set of switching signals used to control the target power transistor to generate switching actions. For example, when the energy storage converter adopts the energy storage conversion control through the two-phase Buck-Boost parallel structure and the interleaved conduction control method shown in the above embodiments, the boost command is a set of control signals used to close the second power transistor S2 and the fourth power transistor S4 and open the first power transistor S1 and the third power transistor S3. That is, the boost command includes the open signal sent to the first power transistor S1, the close signal sent to the second power transistor S2, the open signal sent to the third power transistor S3, and the close signal sent to the fourth power transistor S4.

[0100] In the boost state, the energy storage converter can close the second power transistor S2 and the fourth power transistor S4 and open the first power transistor S1 and the third power transistor S3, so that the Boost branch of the energy storage converter is activated, and the energy storage device can discharge to the DC bus, thereby compensating the voltage of the DC bus.

[0101] When the energy storage device discharges to the DC bus, in order to quickly compensate the bus voltage of the DC bus, the maximum current discharge method can be used for power transmission. The maximum current refers to the maximum continuous discharge current that the energy storage device can provide under the conditions of safe and reliable operation.

[0102] S103. If the bus voltage is greater than or equal to the upper limit voltage, send a buck command to the energy storage converter.

[0103] By comparing the bus voltage U with the upper limit voltage U2, when the bus voltage U is greater than or equal to the upper limit voltage U2, the controller can generate a buck command and send the buck command to the energy storage converter. Among them, the buck command is used to make the energy storage converter in the maximum current charge state, that is, the buck command can control the energy storage converter to switch to use the buck conversion branch, so that the current flows from the DC bus to the energy storage device to charge the energy storage device, so as to store the excess electric energy on the DC bus.

[0104] For example, after detecting the bus voltage U of the DC bus through a voltage sensor, the controller compares the bus voltage U with the upper limit voltage U3 of the fluctuation range [U2, U3]. When the bus voltage U of the DC bus rises to the set upper limit voltage U3, a set of control signals for closing the first power transistor S1 and the third power transistor S3 and disconnecting the second power transistor S2 and the fourth power transistor S4 can be generated to obtain a buck command. Then, the buck command is sent to the energy storage converter to switch the energy storage converter to the buck mode, enabling the DC bus to charge the energy storage device.

[0105] When the DC bus charges the energy storage device, the maximum current charging method can also be adopted, that is, the energy storage device can be adjusted to the highest charging power for fast charging. Similarly, according to the different types of energy storage devices, the maximum charging current can also be different. For example, when the energy storage device is a lithium iron phosphate battery, the maximum charging current is 80A.

[0106] S104. If the bus voltage is equal to the standard operating voltage, send a standby command to the energy storage converter.

[0107] By comparing the bus voltage with the standard operating voltage, when the bus voltage is equal to the standard operating voltage, the controller can generate a standby command and send the standby command to the energy storage converter. Among them, the standby command is used to make the energy storage converter stop discharging or charging, that is, to be in the standby state. In the standby state, the energy storage converter does not transfer electric energy between the energy storage device and the DC bus, which is equivalent to cutting off the connection between the energy storage device and the DC bus.

[0108] The controller can generate and send a standby command to the energy storage converter under different judgment results. In some embodiments, after sending a boost command or a buck command to the energy storage converter, the controller can monitor the bus voltage of the DC bus in real time. When the bus voltage rises to the standard operating voltage or drops to the standard operating voltage, a standby command can be generated.

[0109] For example, as Figure 4As shown, after initializing devices such as the execution clock, pins, PWM, interrupts, serial ports, digital-to-analog converters, analog-to-digital converters, timers, and comparators, the controller obtains the bus voltage of the DC bus in real time. When the bus voltage U of the DC bus drops below the set lower limit voltage U2, according to the control method of step S102, the energy storage converter can be switched to the boost mode, enabling the energy storage device to discharge to the DC bus. At this time, the energy storage device can discharge through the maximum current to supplement electrical energy to the DC bus. As the energy storage device continuously supplements electrical energy to the DC bus, the bus voltage of the DC bus will gradually increase. When it is detected that the DC bus voltage rises to the standard operating voltage U1, a standby command can be generated to switch the energy storage converter to standby. At this time, the energy storage device stops discharging and continuously detects the bus voltage of the DC bus, thereby maintaining the bus voltage of the DC bus within the set fluctuation range.

[0110] For another example, as Figure 5 shown, when the bus voltage U of the DC bus rises above the set upper limit voltage U3, according to the control method of step S103, the energy storage converter can be switched to the buck mode, enabling the energy storage device to discharge to the DC bus. At this time, the energy storage device can charge through the maximum current to obtain electrical energy from the DC bus and convert the electrical energy into other forms of energy for energy storage. During the process of the DC bus transmitting electrical energy to the energy storage device, the bus voltage of the DC bus can be reduced. When it is detected that the DC bus voltage drops to the standard operating voltage U1, a standby command can be generated to switch the energy storage converter to standby, so as to maintain the bus voltage of the DC bus within the set fluctuation range.

[0111] In some embodiments, the standby command can also be generated by comparing the bus voltage with the lower limit voltage U2 and the upper limit voltage U3. When the bus voltage is greater than the lower limit voltage U2 and less than the upper limit voltage U3 at the same time, it can be determined that the current power supply system is within the normal fluctuation range. At this time, a standby command can be generated to stop the transfer of electrical energy between the energy storage device and the DC bus, reducing the device loss caused by the frequent charging and discharging of the energy storage device.

[0112] As Figure 6 shown, by applying the technical solutions provided in the above embodiments, the system can achieve the bidirectional flow of energy between the energy storage device and the DC bus, enabling the energy storage device to perform flexible charging and discharging according to the DC bus voltage, alleviating the DC bus voltage fluctuation, and improving the overall operation performance of the system.

[0113] Furthermore, as a refinement and extension of the specific implementation manner of the above embodiments, in order to fully illustrate the specific implementation process of this embodiment, some embodiments of this application also provide a highly secure energy storage system applicable to a zero-carbon power supply station, as Figure 7As shown, the protection device of the system further includes second transmitters T1 to TN; the power sensor further includes a current sensor. Among them, the current sensor is arranged between the DC bus and the energy storage converter, and the current sensor is connected to the controller. The current sensor is configured to induce a second electrical signal according to the current on the energy storage branch. The second transmitter is arranged between the current sensor and the controller, and the second transmitter is configured to convert the second electrical signal induced by the current sensor into an electrical signal that the controller can receive to obtain the protection current. For example, the second transmitter can process the collected current through interval mapping, analog-to-digital conversion, etc. into a small digital voltage that the controller can read and receive.

[0114] As Figure 8 shown, the controller is further configured to:

[0115] S201. Obtain the protection current and the preset current judgment interval;

[0116] S202. If the protection current is not within the current judgment interval, query the target energy storage branch to which the current sensor belongs;

[0117] S203. Send a disconnection instruction to the circuit breaker on the target energy storage branch.

[0118] When the power sensor of the protection device includes a current sensor, the current sensors can be respectively arranged on each energy storage branch, and the protection device can detect the current information of each energy storage branch according to the current sensors on each energy storage branch, so as to realize fault protection according to the current information.

[0119] Since the current information of each energy storage branch is used to realize fault protection, in this embodiment, the current of each energy storage branch detected by the current sensor is called the protection current. After the current sensor induces a second electrical signal according to the current of each energy storage branch, the second electrical signal can be transmitted to the second transmitter, and the second transmitter converts the second electrical signal into protection current data that the controller can recognize, that is, protection currents I1 to IN. Then, the data corresponding to the protection currents I1 to IN is sent to the controller.

[0120] After receiving the protection current, the controller can extract the current judgment interval from the preset application program. According to different fault types for which fault protection is to be performed, the current judgment interval is also different. For example, when the protection device performs overcurrent instantaneous trip protection for multiple branches, the current threshold for overcurrent instantaneous trip protection, that is, the operating current, can be preset. Since the instantaneous current quick-break protection can include multiple current stages, multiple current thresholds can be set according to different current stages.

[0121] After obtaining the protection current and the preset current judgment interval, the controller can compare the protection current with the preset current judgment interval. If the protection current is within the current judgment interval, it indicates that the corresponding energy storage branch has not failed. Therefore, there is no need to perform a fault protection action, and it is only necessary to continuously monitor the protection current.

[0122] If the protection current is not within the current judgment interval, it indicates that the corresponding energy storage branch may have failed. At this time, the controller can query the target energy storage branch to which the current sensor belongs according to the identification information of the current sensor. For example, when the protection current I is not within the current judgment interval [I1, I2], the identification information A1 of the current sensor corresponding to the protection current I can be queried, and then the target energy storage branch can be queried according to the pre-determined corresponding relationship between the identification information A1 of the current sensor and the arrangement position (i.e., the energy storage branch).

[0123] Then, a disconnection instruction is sent to the circuit breaker on the target energy storage branch to control the circuit breaker to cut off the connection between the energy storage branch and the DC bus, so as to reduce the impact of the fault in the target energy storage branch on the DC bus and improve the overall power supply quality of the DC bus.

[0124] By applying the technical solution of this embodiment, the system can collect the protection current of each energy storage branch based on the current sensor and perform fault judgment according to the protection current, thereby improving the safety of the entire system. By configuring multiple protection functions in the controller of the system, when a fault occurs in a certain branch of the energy storage system, the faulty branch can be quickly cut off to avoid the further spread of the fault and ensure the normal operation of other branches.

[0125] Based on the system provided in the above embodiment, in some embodiments of the present application, an energy storage control method is further provided, which is applied to a high-safety energy storage system suitable for a zero-carbon power supply station. The method includes:

[0126] Obtain the bus voltage collected by the power sensor and the preset energy storage control parameters. The energy storage control parameters include the standard working voltage and the fluctuation range; the standard working voltage is within the fluctuation range; the fluctuation range includes the upper limit voltage and the lower limit voltage;

[0127] If the bus voltage is less than or equal to the lower limit voltage, send a boost instruction to the energy storage converter. The boost instruction is used to make the energy storage converter in the maximum current discharge state;

[0128] If the bus voltage is greater than or equal to the upper limit voltage, send a buck instruction to the energy storage converter. The buck instruction is used to make the energy storage converter in the maximum current charging state;

[0129] If the bus voltage is equal to the standard operating voltage, a standby instruction is sent to the energy storage converter, and the standby instruction is used to make the energy storage converter stop discharging or charging.

[0130] By applying the technical solution of this embodiment, the embodiment of the present application provides a high - security energy storage system control method applicable to a zero - carbon power supply station. The method can collect the bus voltage and the protection current of the energy storage branch in real time through an electric energy sensor. When the bus voltage is less than or equal to the lower limit voltage, the energy storage converter is controlled to enter the maximum current discharge state; when the bus voltage is equal to the standard operating voltage, the energy storage converter is controlled to maintain the standby state; when the bus voltage is greater than or equal to the upper limit voltage, the energy storage converter is controlled to enter the maximum current charging state. The method can realize the bidirectional flow of energy between the energy storage device and the DC bus, enable the energy storage device to perform flexible charging and discharging according to the DC bus voltage, relieve the DC bus voltage fluctuation, and improve the overall operation performance of the system.

[0131] The embodiment of the present application also provides a computer device, which can specifically be a personal computer, a server, a network device, etc. The computer device includes a bus, a processor, a memory, and a communication interface, and may also include an input - output interface and a display device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non - volatile storage medium and an internal memory. The non - volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non - volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in the method embodiments are implemented.

[0132] Those skilled in the art can understand that the structure of the above - mentioned computer device is only a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components, or combine some components, or have different component arrangements.

[0133] In one embodiment, a computer - readable storage medium is also provided. The computer - readable storage medium can be non - volatile or volatile, and a computer program is stored thereon. When the computer program is executed by the processor, the steps in the above - mentioned method embodiments are implemented.

[0134] In one embodiment, a computer program product is also provided, including a computer program. When the computer program is executed by the processor, the steps in the above - mentioned method embodiments are implemented.

[0135] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0136] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods.

[0137] Among them, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc.

[0138] Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0139] The databases involved in the embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., and are not limited thereto. The processors involved in the embodiments provided in this application can be general-purpose processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., and are not limited thereto.

[0140] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0141] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A high-safety energy storage system suitable for a zero-carbon power supply station, characterized in that: The system comprises: a DC bus, an energy storage device, an energy storage converter and a protection device; Wherein, the energy storage device is connected to the DC bus through the energy storage converter to form an energy storage branch; the protection device includes a circuit breaker, an electric energy sensor and a controller; the circuit breaker is arranged on the energy storage branch, and the circuit breaker is located between the DC bus and the energy storage converter; the electric energy sensor is arranged on the DC bus and / or the energy storage branch; the electric energy sensor is connected to the controller; The controller is configured to: Obtaining the bus voltage collected by the electric energy sensor and the preset energy storage control parameters, wherein the energy storage control parameters include a standard operating voltage and a fluctuation range; the standard operating voltage is within the fluctuation range; the fluctuation range includes an upper voltage limit and a lower voltage limit; If the bus voltage is less than or equal to the lower limit voltage, a voltage boost instruction is sent to the energy storage converter, wherein the voltage boost instruction is used to put the energy storage converter in a maximum current discharge state; If the bus voltage is greater than or equal to the upper limit voltage, a voltage reduction instruction is sent to the energy storage converter, wherein the voltage reduction instruction is used to put the energy storage converter in a maximum current charging state; If the bus voltage is equal to the standard operating voltage, a standby instruction is sent to the energy storage converter, where the standby instruction is used to stop the energy storage converter from being in a discharging state or a charging state.

2. The system according to claim 1, characterized in that The energy storage converter includes a boost conversion branch and a buck conversion branch, the boost conversion branch and the buck conversion branch are arranged in parallel, and are staggeredly turned on based on the boost instruction or the buck instruction; the power tube turn-on signals on the boost conversion branch and the buck conversion branch are staggered by 180°.

3. The system according to claim 2, characterized in that The energy storage converter comprises: a first wire, a second wire, a third wire, a fourth wire, a first power tube, a second power tube, a first diode and a second diode; The first wire is connected to the positive electrode of the energy storage device; the second wire is connected to the negative electrode of the energy storage device; the third wire is connected to the positive electrode of the DC bus; the fourth wire is connected to the negative electrode of the DC bus; the second wire is also connected to the fourth wire; The collector of the first power tube is connected to the cathode of the first diode; the emitter of the first power tube is connected to the anode of the first diode; the collector of the second power tube is connected to the cathode of the second diode; the emitter of the second power tube is connected to the anode of the second diode; The first diode and the second diode are connected in series between the third wire and the fourth wire to form a first branch; the first wire is connected to a first connection point of the first branch, and the first connection point is located between the first diode and the second diode.

4. The system according to claim 3, characterized in that The energy storage converter further includes: a third power tube, a fourth power tube, a third diode and a fourth diode; The collector of the third power tube is connected to the cathode of the third diode; the emitter of the third power tube is connected to the anode of the third diode; the collector of the fourth power tube is connected to the cathode of the fourth diode; the emitter of the fourth power tube is connected to the anode of the fourth diode; The third diode and the fourth diode are connected in series between the third wire and the fourth wire to form a second branch; the first wire is connected to a second connection point of the second branch, and the second connection point is located between the third diode and the fourth diode.

5. The system according to claim 4, characterized in that The energy storage converter is configured as follows: When receiving the boost instruction, the second power tube and the fourth power tube generate a switching action, and freewheel through the first diode and the third diode; When receiving the voltage reduction instruction, the first power tube and the third power tube generate switching action, and freewheeling is performed through the second diode and the fourth diode.

6. The system according to claim 4, characterized in that The energy storage converter further includes: a first inductor and a second inductor; The first inductor is connected between the first conductor and the first connection point; The second inductor is connected between the first conductive line and the second connection point.

7. The system according to claim 4, characterized in that The energy storage converter further includes: a first capacitor and a second capacitor; One end of the first capacitor is connected to the first wire, and the other end of the first capacitor is connected to the second wire; One end of the second capacitor is connected to the third wire, and the other end of the second capacitor is connected to the fourth wire.

8. The system according to claim 1, characterized in that The protection device further comprises a first transmitter; the electric energy sensor comprises a voltage sensor; The voltage sensor is arranged on the DC bus and connected to the controller; the voltage sensor is configured to sense a first electrical signal according to the voltage of the DC bus; The first transmitter is disposed between the voltage sensor and the controller, and is configured to convert a first electrical signal sensed by the voltage sensor into an electrical signal acceptable to the controller, so as to obtain the bus voltage.

9. The system according to claim 1, characterized in that The protection device further comprises a second transmitter; the electric energy sensor further comprises a current sensor; The current sensor is arranged between the DC bus and the energy storage converter, the current sensor is connected to the controller, and the current sensor is configured to sense a second electrical signal according to the current on the energy storage branch; The second transmitter is arranged between the current sensor and the controller, and the second transmitter is configured to convert the second electrical signal sensed by the current sensor into an electrical signal acceptable to the controller to obtain a protection current; The controller is also configured to: Obtaining the protection current and the preset current judgment interval; If the protection current is not within the current judgment interval, query the target energy storage branch to which the current sensor belongs; A disconnect instruction is sent to the circuit breaker on the target energy storage branch.

10. A method for controlling energy storage, characterized in that: The high-safety energy storage system applicable to a zero-carbon power supply station as described in any one of claims 1 to 9, the method comprising: Obtaining the bus voltage collected by the electric energy sensor and the preset energy storage control parameters, wherein the energy storage control parameters include a standard operating voltage and a fluctuation range; the standard operating voltage is within the fluctuation range; the fluctuation range includes an upper voltage limit and a lower voltage limit; If the bus voltage is less than or equal to the lower limit voltage, a voltage boost instruction is sent to the energy storage converter, wherein the voltage boost instruction is used to put the energy storage converter in a maximum current discharge state; If the bus voltage is greater than or equal to the upper limit voltage, a voltage reduction instruction is sent to the energy storage converter, wherein the voltage reduction instruction is used to put the energy storage converter in a maximum current charging state; If the bus voltage is equal to the standard operating voltage, a standby instruction is sent to the energy storage converter, where the standby instruction is used to stop the energy storage converter from being in a discharging state or a charging state.

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