Integrated energy storage system and control method

Abstract

The invention discloses an integrated energy storage system and a control method, the integrated energy storage system comprises a battery management system, an energy management system and an energy storage converter, the energy management system generates a charging and discharging control signal to the energy storage converter according to battery information of an energy storage battery acquired by the battery management system and a received charging and discharging instruction; and the energy storage converter is controlled through the charging and discharging control signal, so that the energy storage converter transmits the electric energy stored by the energy storage battery to a power grid or stores the electric energy in the power grid into the energy storage battery, namely, charging and discharging between the energy storage battery and the power grid are realized. Visibly, the battery management system, the energy management system and the energy storage converter are integrated, the battery management system and the energy storage converter only need to communicate with the energy management system, and the energy management system performs centralized management on the battery management system and the energy storage converter; and the system can be put into use without connecting and testing each part, so that the charging and discharging efficiency of the energy storage system is improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage systems, and in particular to an integrated energy storage system and a control method. Background Art

[0002] Energy storage system is a device that can store electrical energy and release it when needed. It plays a vital role in the fields of power system, utilization of renewable energy and power supply and demand regulation. Energy storage system in the prior art is usually a distributed system. The control strategies of each distributed node of the energy storage system are different. The communication and coordination between different nodes are very complex. Before it is put into use, each distributed node needs to be connected and tested, which is time-consuming and complicated. Summary of the invention

[0003] The purpose of the present invention is to provide an integrated energy storage system and control method, which integrates a battery management system, an energy management system and an energy storage inverter. The battery management system and the energy storage inverter only need to communicate with the energy management system, and the energy management system centrally manages the battery management system and the energy storage inverter. They can be put into use without connecting and testing each part, thereby improving the charging and discharging efficiency of the energy storage system.

[0004] In order to solve the above technical problems, the present invention provides an integrated energy storage system, including a battery management system, an energy management system and an energy storage converter; the energy storage converter is connected between the energy storage battery and the power grid, the battery management system is connected to the energy storage battery and the energy management system, and the energy management system is connected to the energy storage converter;

[0005] The battery management system is used to obtain battery information of the energy storage battery and send it to the energy management system;

[0006] The energy management system is used to send a charge and discharge control signal to the energy storage converter based on the battery information and the charge and discharge instruction;

[0007] The energy storage converter is used to transmit the electric energy stored in the energy storage battery to the power grid, or to store the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal.

[0008] Preferably, it also includes a DC circuit breaker connected between the energy storage converter and the energy storage battery and an AC circuit breaker connected between the energy storage converter and the power grid;

[0009] The energy management system is also used to send a circuit breaker on command to the battery management system when power is turned on, and send a circuit breaker off command to the battery management system when it is determined based on the battery information that the energy storage battery is in an abnormal working state;

[0010] The battery management system is connected to the control end of the DC circuit breaker and the control end of the AC circuit breaker, and is also used to control the DC circuit breaker and the AC circuit breaker to be turned on when receiving the circuit breaker turn-on instruction, and to control the DC circuit breaker and the AC circuit breaker to be turned off when receiving the circuit breaker turn-off instruction.

[0011] Preferably, it also includes:

[0012] An AC side residual current transformer having an input end connected to the AC side of the energy storage converter, and used for collecting AC side leakage current of the energy storage converter;

[0013] An electrical fire monitoring module whose input end is connected to the output end of the AC side residual current transformer, and is used to output a leakage current prompt signal when the AC side leakage current is greater than a preset leakage current;

[0014] The fire protection system, whose input end is connected to the output end of the electrical fire monitoring module and whose output end is connected to the battery management system, is used to output the circuit breaker shutdown instruction after receiving the leakage current prompt signal, so that the battery management system controls the DC circuit breaker and the AC circuit breaker to shut down when receiving the circuit breaker shutdown instruction.

[0015] Preferably, it also includes:

[0016] A power supply module having an input end connected to the energy storage battery and the power grid, and an output end respectively connected to the battery management system, the energy management system and the energy storage inverter, for powering the battery management system, the energy management system and the energy storage inverter based on the electric energy stored in the energy storage battery or the electric energy of the power grid.

[0017] Preferably, the energy storage converter comprises an AC / DC conversion module and a control module; the AC / DC conversion module is connected between the energy storage battery and the power grid, and the control module is connected between the AC / DC conversion module and the energy management system;

[0018] The control module is used to control the AC / DC conversion module based on the charge and discharge control signal, so that the AC / DC conversion module converts the DC power in the energy storage battery into AC power and transmits it to the power grid, or converts the AC power in the power grid into DC power and stores it in the energy storage battery.

[0019] Preferably, the energy storage converter further includes:

[0020] The bus capacitor connected between the energy storage battery and the AC / DC conversion module is used to filter the direct current output by the energy storage battery and transmit it to the AC / DC conversion module, or to filter the direct current output by the AC / DC conversion module and transmit it to the energy storage battery.

[0021] In order to solve the above technical problems, the present invention provides a control method of an integrated energy storage system, which is applied to the energy management system in the above integrated energy storage system, and the method comprises:

[0022] Obtain the battery information of the energy storage battery output by the battery management system;

[0023] When receiving a charge and discharge instruction, a charge and discharge control signal is generated based on the battery information, so that the energy storage inverter transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal.

[0024] Preferably, the battery information of the energy storage battery includes the remaining battery capacity and battery health parameters of the energy storage battery;

[0025] When receiving a charge and discharge instruction, a charge and discharge control signal is generated based on the battery information, so that the energy storage converter transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal, including:

[0026] Upon receiving a discharge instruction, a discharge control signal is generated based on the battery information, so that the energy storage converter transmits the electric energy stored in the energy storage battery to the power grid based on the discharge control signal, and stops outputting the discharge control signal when the remaining battery capacity of the energy storage battery is greater than a preset maximum capacity threshold;

[0027] When a charging instruction is received, a charging control signal is generated based on the battery information, so that the energy storage inverter stores the electric energy in the power grid into the energy storage battery based on the charging control signal, and stops outputting the charging control signal when the remaining battery capacity of the energy storage battery is less than a preset minimum capacity threshold.

[0028] Preferably, the battery information of the energy storage battery also includes battery temperature information;

[0029] After obtaining the battery information of the energy storage battery output by the battery management system, it also includes:

[0030] When it is determined based on the battery temperature information that the temperature of the energy storage battery is greater than a preset temperature threshold, the charge and discharge control signal is stopped from being output, and an over-temperature alarm signal is output to the battery management system, so that the battery management system issues a battery over-temperature alarm based on the over-temperature alarm signal.

[0031] Preferably, the battery information of the energy storage battery also includes the voltage of each single cell in the energy storage battery;

[0032] After obtaining the battery information of the energy storage battery output by the battery management system, it also includes:

[0033] When the voltages of the individual cells in the energy storage battery are inconsistent, the charge and discharge control signal is stopped from being output, and a battery balancing instruction is output to the battery management system, so that the battery management system performs balancing processing on the individual cells in the energy storage battery based on the battery balancing instruction until the voltages of the individual cells in the energy storage battery are consistent.

[0034] The present application provides an integrated energy storage system and control method, which includes a battery management system, an energy management system and an energy storage inverter. The energy management system generates a charge and discharge control signal to the energy storage inverter based on the battery information of the energy storage battery obtained by the battery management system and the charge and discharge instructions received, thereby controlling the energy storage inverter through the charge and discharge control signal, so that the energy storage inverter transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid into the energy storage battery, that is, realizes the charge and discharge between the energy storage battery and the power grid. It can be seen that the battery management system, the energy management system and the energy storage inverter are integrated in the present application, and the battery management system and the energy storage inverter only need to communicate with the energy management system, and the energy management system centrally manages the battery management system and the energy storage inverter, and can be put into use without connecting and testing each part, thereby improving the charge and discharge efficiency of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the structure of an integrated energy storage system provided in this application;

[0037] Figure 2 A specific structural schematic diagram of an integrated energy storage system provided in this application;

[0038] Figure 3A schematic flow chart of a control method for an integrated energy storage system provided in the present application. DETAILED DESCRIPTION

[0039] The core of the present invention is to provide an integrated energy storage system and control method, which integrates a battery management system, an energy management system and an energy storage inverter. The battery management system and the energy storage inverter only need to communicate with the energy management system, and the energy management system centrally manages the battery management system and the energy storage inverter. They can be put into use without connecting and testing each part, thereby improving the charging and discharging efficiency of the energy storage system.

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Please refer to Figure 1 , Figure 1 A structural schematic diagram of an integrated energy storage system provided in the present application, including a battery management system 1, an energy management system 2 and an energy storage converter 3; the energy storage converter 3 is connected between the energy storage battery and the power grid, the battery management system 1 is connected to the energy storage battery and the energy management system 2, and the energy management system 2 is connected to the energy storage converter 3;

[0042] The battery management system 1 is used to obtain the battery information of the energy storage battery and send it to the energy management system 2;

[0043] The energy management system 2 is used to send a charge and discharge control signal to the energy storage converter 3 based on the battery information and the charge and discharge instructions;

[0044] The energy storage converter 3 is used to transmit the electric energy stored in the energy storage battery to the power grid, or to store the electric energy in the power grid into the energy storage battery based on the charge and discharge control signal.

[0045] An energy storage system is a device that can store electrical energy or output the stored electrical energy. An energy storage system applied to a power grid can store excess electrical energy when the power supply of the power grid exceeds the demand, and release the stored electrical energy at the peak of the power demand of the power grid to reduce the load fluctuation of the power grid, ensure the smooth operation of the power grid, and improve the operating efficiency of the power grid. In addition, by quickly responding to the frequency and voltage changes of the power grid, the energy storage system can provide frequency regulation and voltage support for the power grid, and enhance the stability and reliability of the power grid. In particular, for renewable energy, the energy storage system can smooth the output fluctuations of renewable energy, such as wind power and photovoltaics, improve their reliability and stability, and thus increase the proportion of renewable energy in the power grid. If the energy storage system is a distributed system, it is necessary to connect the distributed nodes before it is put into use. Since different distributed nodes may be manufactured by different manufacturers, their control strategies may be different. When connecting and debugging the distributed nodes, there may be failures such as failure to communicate normally. At this time, relevant professionals are required to perform targeted maintenance and management operations. The process of troubleshooting is complicated and tedious. If it takes too long, the energy storage system will not be able to be put into use for a long time. Or if the energy storage system fails after it is put into use, relevant professionals are also required to troubleshoot the failure, which will also cause the energy storage system to be unable to work normally for a long time.

[0046] In order to solve the above technical problems, the integrated energy storage system in the present application includes a battery management system 1, an energy management system 2 and an energy storage inverter 3, wherein the energy management system 2 uniformly manages the battery management system 1 and the energy storage inverter 3, the battery management system 1 is responsible for acquiring the battery information of the energy storage battery, and the energy management system 2 controls the energy storage inverter 3 based on the battery information, so that the energy storage inverter 3 stores the electric energy in the power grid into the energy storage battery, or releases the electric energy stored in the energy storage battery to the power grid. That is, the battery management system 1, the energy management system 2 and the energy storage inverter 3 are integrated together, and the energy management system 2 uniformly dispatches them. If a fault occurs, the cause of the fault can be located through the energy management system 2, such as determining that the battery information obtained by the battery management system 1 is abnormal, or determining that the energy storage inverter 3 cannot normally execute the charge and discharge control signal, or determining that the fault is caused by the energy management system 2 being unable to normally output the charge and discharge control signal.

[0047] Based on this, the battery management system 1, the energy management system 2 and the energy storage inverter 3 are integrated into a control cabinet before being put into use. The integrated control cabinet can be directly used to store the electric energy in the power grid or release the electric energy in the energy storage battery. It can be put into use without debugging, and there is no need for different technicians to perform fault analysis separately, which improves the working efficiency of the integrated energy storage system.

[0048] Among them, the energy management system 2 can interact with the staff, receive the charge and discharge instructions sent by the staff, and then output the corresponding charge and discharge control signal based on the charge and discharge instructions, so that the energy storage converter 3 can perform corresponding charge and discharge control on the energy storage battery. In addition, when the energy storage battery is charged and discharged, the battery information of the energy storage battery must also be considered, such as whether the energy storage battery can currently store and release electric energy normally, so as to ensure the normal operation of the energy storage battery. Through human-computer interaction with the staff, the energy management system 2 can also show the staff the working process of the battery management system 1, the energy management system 2 and the energy storage converter 3. For example, if the energy management system 2 is connected to a display screen, the battery parameters of the energy storage battery obtained by the battery management system 1 can be displayed on the display screen, the battery parameters received by the energy management system 2, the received charge and discharge instructions, and the output charge and discharge control signals, and the output voltage, output current, and output power of the energy storage converter 3 can be displayed, so that the staff can view the working status of the entire integrated energy storage system and locate the cause of the fault when the integrated energy storage system works abnormally.

[0049] It should also be noted that since the battery management system 1, the energy management system 2 and the energy storage inverter 3 are integrated in the present application, the integrated energy storage system in the present application can be put into use directly without the need to test or maintain the battery management system 1, the energy management system 2 and the energy storage inverter 3 separately before putting them into use, and the working stability of the integrated energy storage system is also higher.

[0050] In summary, in this application, the battery management system 1, the energy management system 2 and the energy storage inverter 3 are integrated. The battery management system 1 and the energy storage inverter 3 only need to communicate with the energy management system 2, and the energy management system 2 centrally manages the battery management system 1 and the energy storage inverter 3. They can be put into use without connecting and testing each part, thereby improving the charging and discharging efficiency of the energy storage system.

[0051] Based on the above embodiments:

[0052] Please refer to Figure 2 , Figure 2 A specific structural schematic diagram of an integrated energy storage system provided in this application.

[0053] As a preferred embodiment, it also includes a DC circuit breaker connected between the energy storage converter 3 and the energy storage battery and an AC circuit breaker connected between the energy storage converter 3 and the power grid;

[0054] The energy management system 2 is also used to send a circuit breaker on command to the battery management system 1 when power is turned on, and to send a circuit breaker off command to the battery management system 1 when it is determined based on the battery information that the energy storage battery is in an abnormal working state;

[0055] The battery management system 1 is connected to the control end of the DC circuit breaker and the control end of the AC circuit breaker, and is also used to control the DC circuit breaker and the AC circuit breaker to be turned on when a circuit breaker turn-on instruction is received, and to control the DC circuit breaker and the AC circuit breaker to be turned off when a circuit breaker turn-off instruction is received.

[0056] In this embodiment, a DC circuit breaker and an AC circuit breaker are respectively provided at both ends of the energy storage inverter 3. The on and off of the DC circuit breaker determines the on and off of the circuit between the energy storage inverter 3 and the energy storage battery, and the on and off of the AC circuit breaker determines the on and off of the circuit between the energy storage inverter 3 and the power grid.

[0057] When the energy management system 2 is powered on, it outputs a circuit breaker conduction instruction to the battery management system 1, so that the battery management system 1 controls the DC circuit breaker and the AC circuit breaker to be turned on, so that the energy storage inverter 3 is connected to the energy storage battery and the power grid. Subsequently, when the energy management system 2 receives the charge and discharge instruction, it sends a charge and discharge control signal to the energy storage inverter, so that the energy storage inverter performs energy transmission between the energy storage battery and the power grid based on the charge and discharge control signal, including charging or discharging the energy storage battery; however, if the energy management system 2 determines that the energy storage battery is in an abnormal working state, it promptly outputs a circuit breaker shutdown instruction, so that the battery management system 1 controls the DC circuit breaker and the AC circuit breaker to be turned off, and disconnects the energy storage inverter 3 from the energy storage battery and the power grid.

[0058] Therefore, as long as the energy management system 2 or the integrated energy storage system is powered on, the energy management system 2 will output a circuit breaker conduction instruction to enable the battery management system 1 to control the DC circuit breaker and the AC circuit breaker to be turned on. When the charge and discharge control signal is not received, the energy storage converter 3 is connected to the energy storage battery and the power grid, but does not perform charging or discharging. The corresponding energy storage battery charging or discharging operation is performed only after the charge and discharge control signal is received. In addition, the DC circuit breaker and the AC circuit breaker can also be turned on based on manual operation by the user, that is, before the energy management system 2 or the integrated energy storage system is powered on, the user first turns on the DC circuit breaker and the AC circuit breaker through manual control, so that the energy management system 2 can subsequently directly output the charge and discharge control signal according to the charge and discharge signal to improve the power conversion efficiency.

[0059] It can be seen that in this embodiment, the energy management system 2 is also centrally controlled. After the energy management system 2 outputs the corresponding circuit breaker conduction instruction and circuit breaker shutdown instruction, the battery management system 1 controls the conduction and shutdown of the DC circuit breaker and the AC circuit breaker, so that it is convenient for the staff to locate the cause of the fault when a fault occurs. For example, if the DC circuit breaker and the AC circuit breaker cannot be normally turned on after power-on, it can be determined that the DC circuit breaker and the AC circuit breaker cannot be normally turned on because the energy management system 2 cannot output the circuit breaker conduction instruction or because the battery management system 1 cannot execute the circuit breaker conduction instruction, so as to facilitate targeted maintenance of the integrated energy storage system. Correspondingly, the energy management system 2 can also display the power-on status of the energy management system 2, as well as the status of the output circuit breaker conduction instruction and circuit breaker shutdown instruction through the display screen, and display the status of the battery management system 1 executing the circuit breaker conduction instruction and circuit breaker shutdown instruction, so as to facilitate the staff to view the working status of the integrated energy storage system.

[0060] In addition, the battery management system 1 can also connect with the DC circuit breaker and the AC circuit breaker to perform insulation sampling on the DC side and the AC side, thereby determining the insulation status of the DC side and the AC side, and feeding back the insulation status to the energy management system 2. When the energy management system 2 determines that the insulation is abnormal, it outputs a circuit breaker shutdown instruction so that the battery management system 1 controls the DC circuit breaker and the AC circuit breaker to shut down, so as to avoid leakage of the DC circuit breaker or the AC circuit breaker and affect the safety of personnel.

[0061] As a preferred embodiment, it also includes:

[0062] An AC side residual current transformer whose input end is connected to the AC side of the energy storage converter 3, and is used to collect the AC side leakage current of the energy storage converter 3;

[0063] An electrical fire monitoring module whose input end is connected to the output end of the AC side residual current transformer, and is used to output a leakage current prompt signal when the AC side leakage current is greater than a preset leakage current;

[0064] The fire protection system whose input end is connected to the output end of the electrical fire monitoring module and whose output end is connected to the battery management system 1 is used to output a circuit breaker shutdown command after receiving a leakage current prompt signal, so that the battery management system 1 controls the DC circuit breaker and the AC circuit breaker to shut down when receiving the circuit breaker shutdown command.

[0065] In this embodiment, an AC side residual current transformer is arranged between the AC side of the energy storage converter 3 and the AC circuit breaker to collect the AC side leakage current of the energy storage converter 3, and transmit the AC side leakage current to the electrical fire monitoring module, so that the electrical fire monitoring module compares the AC side leakage current with the preset leakage current. If the AC side leakage current is not greater than the preset leakage current, it can be determined that the AC side leakage current is too large, and there may be an abnormal situation. At this time, the electrical fire monitoring module outputs a leakage current prompt signal to the fire protection system. In order to avoid the AC side leakage current causing a failure of the entire integrated energy storage system, the fire protection system outputs a circuit breaker shutdown command to the battery management system 1, so that the battery management system 1 shuts down the DC circuit breaker and the AC circuit breaker, thereby avoiding the transmission of power between the power grid and the energy storage battery when the AC side leakage current is large, causing greater damage to the system, and protecting the overall system.

[0066] It should be noted that the AC side residual current transformer is connected to the three-phase line and the neutral line of the AC side of the energy storage converter 3 , so as to detect the AC side leakage current of the energy storage converter 3 .

[0067] As a preferred embodiment, it also includes:

[0068] A power supply module whose input end is connected to the energy storage battery and the power grid, and whose output end is respectively connected to the battery management system 1, the energy management system 2 and the energy storage inverter 3, is used to power the battery management system 1, the energy management system 2 and the energy storage inverter 3 based on the electric energy stored in the energy storage battery or the electric energy of the power grid.

[0069] In this embodiment, a power module is also provided, and the power module draws power from the energy storage battery or from the power grid to charge the battery management system 1, the energy management system 2 and the energy storage inverter 3, thereby ensuring the normal operation of the battery management system 1, the energy management system 2 and the energy storage inverter 3.

[0070] Specifically, when the power module draws power from the energy storage battery, the DC power output by the energy storage battery can be boosted or bucked to output the voltage required for the normal operation of the battery management system 1, the energy management system 2 and the energy storage converter 3, and the battery management system 1, the energy management system 2 and the energy storage converter 3 can be powered after filtering and voltage stabilization. If the power module draws power from the power grid, the AC power output by the power grid can be rectified, and the battery management system 1, the energy management system 2 and the energy storage converter 3 can be powered after filtering and voltage stabilization. If the voltage required for the normal operation of the battery management system 1, the energy management system 2 and the energy storage converter 3 is 24V DC, the power module outputs 24V DC after drawing power from the energy storage battery or the power grid to power the battery management system 1, the energy management system 2 and the energy storage converter 3.

[0071] It should be noted that when the energy in the energy storage battery is insufficient, that is, when the remaining battery capacity of the energy storage battery is greater than the preset maximum capacity threshold, the power module draws power from the power grid, but when the load on the power grid is large, the power module draws power from the energy storage battery, thereby realizing a black start of the battery management system 1, the energy management system 2 and the energy storage inverter 3 powered by the energy storage battery instead of the power grid.

[0072] As a preferred embodiment, the energy storage converter 3 includes an AC / DC conversion module and a control module; the AC / DC conversion module is connected between the energy storage battery and the power grid, and the control module is connected between the AC / DC conversion module and the energy management system 2;

[0073] The control module is used to control the AC / DC conversion module based on the charge and discharge control signal, so that the AC / DC conversion module converts the DC power in the energy storage battery into AC power and transmits it to the power grid, or converts the AC power in the power grid into DC power and stores it in the energy storage battery.

[0074] In this embodiment, the energy storage inverter 3 includes an AC / DC (alternating current / direct current) conversion module and a control module, wherein the control module can control the AC / DC conversion module based on the charge and discharge control signal, so that the AC / DC conversion module inverts the DC power in the energy storage battery into AC power and transmits it to the power grid to realize the discharge of the energy storage battery, or the AC / DC conversion module rectifies the AC power in the power grid into DC power to realize the charging of the energy storage battery.

[0075] It should be noted that the AC / DC conversion module can be implemented by multiple switch tubes, such as Figure 2 The switch tubes Q1, Q2, Q3, Q4, Q5 and Q6 shown in the figure, and the control module can adjust the modulation wave of each switch tube in the AC / DC conversion module based on the charge and discharge control signal, thereby realizing the switching and control of the rectification function or the inverter function of the AC / DC conversion module.

[0076] It should also be noted that when the AC / DC conversion module is connected to the power grid, the three grid connection terminals of the AC / DC conversion module can be connected to the three-phase lines of the power grid respectively, and the neutral line connection terminal of the AC / DC conversion module can be connected to the neutral line of the power grid, so as to obtain the three-phase alternating current of the power grid or output the inverted three-phase alternating current to the power grid. The three grid connection terminals of the AC / DC conversion module connected to the three-phase lines of the power grid are respectively connected to a filter capacitor between the neutral line, such as a first filter capacitor is connected between the first grid connection terminal connected to the a-phase line of the power grid and the neutral line in the AC / DC conversion module, a second filter capacitor is connected between the second grid connection terminal connected to the b-phase line of the power grid and the neutral line, and a third filter capacitor is connected between the third grid connection terminal connected to the c-phase line of the power grid and the neutral line, so that the alternating current obtained from the power grid is filtered and stabilized before being rectified to ensure the stability of the direct current output by the AC / DC conversion module, or the alternating current obtained by inversion is filtered and stabilized, high-frequency noise is filtered out, and energy buffering is performed when instantaneous energy changes occur in the AC / DC conversion module, and then transmitted to the power grid to ensure the stability of the power grid voltage.

[0077] In addition, since the AC / DC conversion module of the integrated energy storage system continuously performs rectification or inversion during the grid-connected process, the heat generated during the operation of the AC / DC conversion module is relatively large. Therefore, the AC / DC conversion module can be placed near the back of the integrated cabinet in the integrated cabinet, and the cooling device can be set on the back of the integrated cabinet to effectively cool the AC / DC conversion module and ensure the normal operation of the AC / DC conversion module. Accordingly, since the heat dissipation of the battery management system 1 and the energy management system 2 is relatively low, the battery management system 1 and the energy management system 2 can be placed near the front of the integrated cabinet, and a small degree of cooling can also be performed by the cooling device.

[0078] As a preferred embodiment, the energy storage converter 3 further includes:

[0079] The bus capacitor connected between the energy storage battery and the AC / DC conversion module is used to filter the DC power output by the energy storage battery and transmit it to the AC / DC conversion module, or to filter the DC power output by the AC / DC conversion module and transmit it to the energy storage battery.

[0080] In this embodiment, a bus capacitor is further provided between the AC / DC conversion module and the energy storage battery, the first end of the bus capacitor is connected to the first end of the energy storage battery and the first end of the AC / DC conversion module, and the second end of the bus capacitor is connected to the second end of the energy storage battery and the second end of the AC / DC conversion module, so that the DC power output by the energy storage battery is filtered and / or voltage stabilized before being transmitted to the AC / DC conversion module to ensure the normal operation of the AC / DC conversion module, or the DC power output by the AC / DC conversion module after rectification is filtered and / or voltage stabilized before being transmitted to the energy storage battery to ensure the stability of the DC bus and the normal operation of the energy storage battery. The first end of the energy storage battery may be a DC positive end, and the second end may be a DC negative end, which is not limited in this application.

[0081] Of course, multiple bus capacitors can be connected in parallel to improve the filtering and voltage stabilization effects on the passing DC power.

[0082] In addition, the bus capacitor can also pre-charge the capacitor in the AC / DC conversion module before the AC / DC conversion module rectifies the DC power output by the energy storage battery to ensure stable operation of the AC / DC conversion module.

[0083] In summary, the first battery terminal of the DC circuit breaker is connected to the first terminal of the energy storage battery, the first conversion terminal is connected to the first DC terminal of the AC / DC conversion module, the second battery terminal is connected to the second terminal of the energy storage battery, and the second conversion terminal is connected to the second DC terminal of the AC / DC conversion module. When the DC circuit breaker is turned on, the first battery terminal of the DC circuit breaker is connected to the first conversion terminal, so that the first terminal of the energy storage battery is connected to the first DC terminal of the AC / DC conversion module, and the second battery terminal of the DC circuit breaker is connected to the second conversion terminal, so that the second terminal of the energy storage battery is connected to the second DC terminal of the AC / DC conversion module; the first grid terminal of the AC circuit breaker is connected to the a phase line of the grid, the second grid terminal is connected to the b phase line of the grid, the third grid terminal is connected to the c phase line of the grid, the neutral line terminal is connected to the neutral line of the grid, the first conversion terminal is connected to the first grid connection terminal of the AC / DC conversion module, and the second conversion terminal is connected to the first grid connection terminal of the AC / DC conversion module. The first grid connection terminal of the AC / DC conversion module is connected to the second grid connection terminal, the third conversion terminal is connected to the third grid connection terminal of the AC / DC conversion module, and the fourth conversion terminal is connected to the neutral line connection terminal of the AC / DC conversion module. When the AC circuit breaker is turned on, the first grid terminal of the AC circuit breaker and the first conversion terminal are turned on, the second grid terminal and the second conversion terminal are turned on, the third grid terminal and the third conversion terminal are turned on, and the neutral line terminal and the fourth conversion terminal are turned on, so that the first grid connection terminal of the AC / DC conversion module is connected to the a phase line of the grid, the second grid connection terminal is connected to the b phase line of the grid, and the third grid connection terminal is connected to the c phase line of the grid. When the battery management system 1 receives the circuit breaker shutdown instruction, the first battery terminal of the DC circuit breaker and the first conversion terminal are disconnected, the second battery terminal and the second conversion terminal are disconnected, the first grid terminal of the AC circuit breaker and the first conversion terminal are disconnected, the second grid terminal and the second conversion terminal are disconnected, the third grid terminal and the third conversion terminal are disconnected, and the neutral line terminal and the fourth conversion terminal are disconnected. A DC fuse can be set between the first conversion terminal of the DC circuit breaker and the first DC terminal of the AC / DC conversion module, which will be blown when the current is too large to provide protection. A DC relay may be provided between the first conversion terminal of the DC circuit breaker and the first DC terminal of the AC / DC conversion module, and between the second conversion terminal and the second DC terminal of the AC / DC conversion module. Figure 2 The main positive relay shown in the figure can also be set with a soft start circuit at both ends of the main positive relay, that is, Figure 2The pre-charging resistor and pre-charging relay in the energy management system 2, before the energy management system 2 outputs the charge and discharge control signal, first turns on the soft start circuit, that is, the pre-charging relay, and turns off the main positive relay, so that when the circuit between the energy storage battery and the AC / DC conversion module is turned on, a smaller current passes through first for protection. After the energy management system 2 outputs the charge and discharge control signal, it first controls the main positive relay to turn on, and then controls the pre-charging relay to turn off, to achieve switching between the pre-charging relay and the main positive relay, to ensure that the current of the energy storage battery and the AC / DC conversion module is uninterrupted, while improving the voltage conversion efficiency of the AC / DC conversion module. Of course, a grid-connected contactor can also be set between the three conversion terminals of the AC circuit breaker and the three grid connection terminals of the AC / DC conversion module. The grid-connected contactor includes three groups of grid-connected contactor contacts, each group of grid-connected contactor contacts is respectively connected between the first conversion terminal of the AC circuit breaker and the first grid connection terminal of the AC / DC conversion module, between the second conversion terminal of the AC circuit breaker and the second grid connection terminal of the AC / DC conversion module, and between the third conversion terminal of the AC circuit breaker and the third grid connection terminal of the AC / DC conversion module. Both ends of each group of grid-connected contactor contacts are respectively connected in parallel with a group of soft start circuits, that is, Figure 2 The soft start resistor and soft start contactor in the energy storage converter 3, before the control module in the energy storage converter 3 receives the charge and discharge control signal, each group of soft start circuits is first turned on, that is, each soft start contactor is turned on first, and then the AC / DC conversion module is controlled to charge or discharge, so that a smaller current passes through the circuit first; after the current of the AC / DC conversion module is stable, each grid-connected contactor contact is turned on first, and then each group of soft start contactors is turned off, so that the AC / DC conversion module performs normal and stable charge and discharge operations. In addition, fuses connected in series with each group of grid-connected contactor contacts can be set to ensure that the circuit between the AC / DC conversion module and the power grid is turned on to protect the circuit. Multiple groups of AC reactors can also be set between the three conversion terminals of the AC circuit breaker and the three power grid connection terminals of the AC / DC conversion module, so as to limit the current between the AC / DC conversion module and the power grid to protect each device. In addition, the battery management system 1 can also collect the voltage of the three-phase line of the power grid through the electric energy meter and transmit it to the energy management system 2, so that the energy management system 2 can adjust the charging and discharging control signal so that the alternating current output by the AC / DC conversion module maintains the stability of the power grid.

[0084] In addition, if Figure 2 As shown, an SPD (Surge Protective Device) may also be connected to the AC side of the energy storage converter 3 to protect the energy storage converter 3 and the power grid from damage caused by surge voltage.

[0085] Please refer to Figure 3 , Figure 3A flow chart of a control method for an integrated energy storage system provided in the present application is applied to an energy management system 2 in the above-mentioned integrated energy storage system. The method includes:

[0086] S11: Obtaining battery information of the energy storage battery output by the battery management system 1;

[0087] S12: upon receiving the charge and discharge instruction, generating a charge and discharge control signal based on the battery information, so that the energy storage converter 3 transmits the electric energy stored in the energy storage battery to the grid, or stores the electric energy in the grid into the energy storage battery based on the charge and discharge control signal.

[0088] In the control of the integrated energy storage system in this embodiment, the energy management system 2 is used for centralized control, so as to ensure the control of the charging and discharging of the energy storage battery by the energy storage inverter 3. For the introduction of the control method of the integrated energy storage system provided by the present invention, please refer to the above-mentioned embodiment of the integrated energy storage system, and the present invention will not be repeated here.

[0089] As a preferred embodiment, the battery information of the energy storage battery includes the remaining battery capacity and battery health parameters of the energy storage battery;

[0090] When receiving the charge and discharge instruction, a charge and discharge control signal is generated based on the battery information, so that the energy storage converter 3 transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal, including:

[0091] When a discharge instruction is received, a discharge control signal is generated based on the battery information, so that the energy storage converter 3 transmits the electric energy stored in the energy storage battery to the power grid based on the discharge control signal, and stops outputting the discharge control signal when the remaining battery capacity of the energy storage battery is greater than a preset maximum capacity threshold;

[0092] When a charging instruction is received, a charging control signal is generated based on the battery information, so that the energy storage inverter 3 stores the electric energy in the power grid into the energy storage battery based on the charging control signal, and stops outputting the charging control signal when the remaining battery capacity of the energy storage battery is less than the preset minimum capacity threshold.

[0093] In this embodiment, when a charging instruction is received, not only a charging control signal is generated to enable the energy storage inverter 3 to charge the energy storage battery based on the charging control signal, but also the remaining battery capacity of the energy storage battery is considered. When the remaining battery capacity of the energy storage battery is insufficient, that is, when the energy storage battery stores a large amount of electrical energy, it is necessary to stop charging the energy storage battery to avoid overcharging the energy storage battery.

[0094] When receiving a discharge instruction, not only a discharge control signal is generated to enable the energy storage inverter 3 to control the energy storage battery to discharge based on the discharge control signal, but also whether the remaining battery capacity of the energy storage battery is too large, that is, whether the electric energy stored in the energy storage battery is insufficient, if insufficient, the energy storage battery cannot be discharged to avoid over-discharge of the energy storage battery.

[0095] Based on the battery health parameters in the battery information, the health status of the energy storage battery can be determined, that is, the ratio of the actual capacity of the energy storage battery to its designed capacity, so as to determine the degree of degradation, service life and performance of the energy storage battery, so as to adjust the preset maximum capacity threshold and the preset minimum capacity threshold of the energy storage battery, or issue a prompt to replace the energy storage battery.

[0096] As a preferred embodiment, the battery information of the energy storage battery also includes battery temperature information;

[0097] After obtaining the battery information of the energy storage battery output by the battery management system 1, it also includes:

[0098] When it is determined based on the battery temperature information that the temperature of the energy storage battery is greater than the preset temperature threshold, the charge and discharge control signal is stopped from being output, and an over-temperature alarm signal is output to the battery management system 1, so that the battery management system 1 issues a battery over-temperature alarm based on the over-temperature alarm signal.

[0099] In this embodiment, the battery information of the energy storage battery collected by the battery management system 1 also includes battery temperature information. The energy management system 2 analyzes the battery temperature information to determine whether the temperature of the energy storage battery is greater than a preset temperature threshold. If greater, the charge and discharge control signal is stopped from being output, so that the energy storage inverter 3 stops charging or discharging the energy storage battery to avoid greater damage to the energy storage battery, and an over-temperature alarm signal is output to the battery management system 1 so that the battery management system 1 issues a battery over-temperature alarm to prompt the staff to cool down the battery.

[0100] If a DC circuit breaker and an AC circuit breaker are provided, then in order to protect the energy storage battery from over-temperature, the DC circuit breaker and the AC circuit breaker may also be disconnected to avoid continued charging or discharging of the energy storage battery, thereby increasing the service life of the energy storage battery.

[0101] Of course, if it is subsequently determined through the battery temperature information that the temperature of the energy storage battery is not greater than the preset temperature threshold, the energy management system 2 can re-output the circuit breaker conduction instruction and the charge and discharge control signal, so that the battery management system 1 controls the DC circuit breaker and the AC circuit breaker to be turned on, so that the energy storage inverter 3 continues to charge and discharge the energy storage battery, so that the energy storage battery can be put into use again.

[0102] As a preferred embodiment, the battery information of the energy storage battery also includes the voltage of each single cell in the energy storage battery;

[0103] After obtaining the battery information of the energy storage battery output by the battery management system 1, it also includes:

[0104] When the voltages of the individual cells in the energy storage battery are inconsistent, the charge and discharge control signal is stopped from being output, and a battery balancing instruction is output to the battery management system 1, so that the battery management system 1 performs balancing processing on the individual cells in the energy storage battery based on the battery balancing instruction until the voltages of the individual cells in the energy storage battery are consistent.

[0105] In this embodiment, the battery management system 1 collects the voltage of each single cell in the energy storage battery, and determines whether the voltage of each single cell is consistent, so as to determine whether each single cell is working normally. If the voltage of each single cell is consistent, then each single cell can be charged and discharged normally. However, if the voltage of the single cell is inconsistent, and the voltage of at least one single cell is inconsistent with that of other single cells, it will affect the overall life and charging and discharging efficiency of the energy storage system. At this time, the energy management system 2 stops outputting the charging and discharging control signal to stop the energy storage inverter 3 from charging or discharging the energy storage battery, that is, the energy storage battery is in a static state, and outputs the battery balancing instruction, so that the battery management system 1 balances the single cells of the specification to ensure the consistency of the voltage of each single cell.

[0106] It should be noted that when the battery management system 1 performs balancing on each single cell, it can be achieved through passive balancing or active balancing. Among them, passive balancing is to balance the charge state of each single cell by consuming excess electrical energy. When the voltage of a single cell is higher than the voltage of other single cells, the battery management system 1 releases the excess energy through a resistor in parallel with the single cell, so that the voltage of the single cell is consistent with that of other single cells. The advantages of passive balancing are low cost, simple circuit design, and easy implementation of software and hardware. Active balancing achieves the purpose of balancing by energy transfer, specifically by cutting high and filling low, including capacitive balancing, inductive balancing, and transformer balancing, that is, transferring part of the energy of the single cell with higher voltage to the single cell with lower voltage, so that the voltage of each single cell is kept consistent. The advantages of active balancing are high efficiency and low loss. This application does not limit the selection of which balancing method to use.

[0107] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0108] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An integrated energy storage system, characterized in that: It includes a battery management system, an energy management system and an energy storage converter; the energy storage converter is connected between the energy storage battery and the power grid, the battery management system is connected to the energy storage battery and the energy management system, and the energy management system is connected to the energy storage converter; The battery management system is used to obtain battery information of the energy storage battery and send it to the energy management system; The energy management system is used to send a charge and discharge control signal to the energy storage converter based on the battery information and the charge and discharge instruction; The energy storage converter is used to transmit the electric energy stored in the energy storage battery to the power grid, or to store the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal.

2. The integrated energy storage system according to claim 1, characterized in that: It also includes a DC circuit breaker connected between the energy storage converter and the energy storage battery and an AC circuit breaker connected between the energy storage converter and the power grid; The energy management system is also used to send a circuit breaker on command to the battery management system when power is turned on, and send a circuit breaker off command to the battery management system when it is determined based on the battery information that the energy storage battery is in an abnormal working state; The battery management system is connected to the control end of the DC circuit breaker and the control end of the AC circuit breaker, and is also used to control the DC circuit breaker and the AC circuit breaker to be turned on when receiving the circuit breaker turn-on instruction, and to control the DC circuit breaker and the AC circuit breaker to be turned off when receiving the circuit breaker turn-off instruction.

3. The integrated energy storage system according to claim 2, characterized in that: Also includes: An AC side residual current transformer having an input end connected to the AC side of the energy storage converter, and used for collecting AC side leakage current of the energy storage converter; An electrical fire monitoring module whose input end is connected to the output end of the AC side residual current transformer, and is used to output a leakage current prompt signal when the AC side leakage current is greater than a preset leakage current; The fire protection system, whose input end is connected to the output end of the electrical fire monitoring module and whose output end is connected to the battery management system, is used to output the circuit breaker shutdown instruction after receiving the leakage current prompt signal, so that the battery management system controls the DC circuit breaker and the AC circuit breaker to shut down when receiving the circuit breaker shutdown instruction.

4. The integrated energy storage system according to claim 1, characterized in that: Also includes: A power supply module having an input end connected to the energy storage battery and the power grid, and an output end respectively connected to the battery management system, the energy management system and the energy storage inverter, for powering the battery management system, the energy management system and the energy storage inverter based on the electric energy stored in the energy storage battery or the electric energy of the power grid.

5. The integrated energy storage system according to any one of claims 1 to 4, characterized in that: The energy storage converter includes an AC / DC conversion module and a control module; the AC / DC conversion module is connected between the energy storage battery and the power grid, and the control module is connected between the AC / DC conversion module and the energy management system; The control module is used to control the AC / DC conversion module based on the charge and discharge control signal, so that the AC / DC conversion module converts the DC power in the energy storage battery into AC power and transmits it to the power grid, or converts the AC power in the power grid into DC power and stores it in the energy storage battery.

6. The integrated energy storage system according to claim 5, characterized in that: The energy storage converter also includes: The bus capacitor connected between the energy storage battery and the AC / DC conversion module is used to filter the direct current output by the energy storage battery and transmit it to the AC / DC conversion module, or to filter the direct current output by the AC / DC conversion module and transmit it to the energy storage battery.

7. A control method for an integrated energy storage system, characterized in that: An energy management system applied to an integrated energy storage system according to any one of claims 1 to 6, the method comprising: Obtain the battery information of the energy storage battery output by the battery management system; When receiving a charge and discharge instruction, a charge and discharge control signal is generated based on the battery information, so that the energy storage inverter transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal.

8. The control method of the integrated energy storage system according to claim 7, characterized in that: The battery information of the energy storage battery includes the remaining battery capacity and battery health parameters of the energy storage battery; When receiving a charge and discharge instruction, a charge and discharge control signal is generated based on the battery information, so that the energy storage converter transmits the electric energy stored in the energy storage battery to the power grid, or stores the electric energy in the power grid in the energy storage battery based on the charge and discharge control signal, including: Upon receiving a discharge instruction, a discharge control signal is generated based on the battery information, so that the energy storage converter transmits the electric energy stored in the energy storage battery to the power grid based on the discharge control signal, and stops outputting the discharge control signal when the remaining battery capacity of the energy storage battery is greater than a preset maximum capacity threshold; When a charging instruction is received, a charging control signal is generated based on the battery information, so that the energy storage inverter stores the electric energy in the power grid into the energy storage battery based on the charging control signal, and stops outputting the charging control signal when the remaining battery capacity of the energy storage battery is less than a preset minimum capacity threshold.

9. The control method of the integrated energy storage system according to claim 8, characterized in that: The battery information of the energy storage battery also includes battery temperature information; After obtaining the battery information of the energy storage battery output by the battery management system, it also includes: When it is determined based on the battery temperature information that the temperature of the energy storage battery is greater than a preset temperature threshold, the charge and discharge control signal is stopped from being output, and an over-temperature alarm signal is output to the battery management system, so that the battery management system issues a battery over-temperature alarm based on the over-temperature alarm signal.

10. The control method of the integrated energy storage system according to claim 8, characterized in that: The battery information of the energy storage battery also includes the voltage of each single cell in the energy storage battery; After obtaining the battery information of the energy storage battery output by the battery management system, it also includes: When the voltages of the individual cells in the energy storage battery are inconsistent, the charge and discharge control signal is stopped from being output, and a battery balancing instruction is output to the battery management system, so that the battery management system performs balancing processing on the individual cells in the energy storage battery based on the battery balancing instruction until the voltages of the individual cells in the energy storage battery are consistent.

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