Patent Application
20250105662
Embodiments relate to the field of energy storage technologies, and to an energy storage cabinet and an energy storage system.
An energy storage system is a bidirectional energy interaction product and is used in scenarios such as a backup power supply, power smoothing on a power generation side, and peak cutting and valley filling on a user side. When a power failure occurs on an entire power grid or the energy storage system is installed for the first time, the system is in an off-grid mode and no alternating current is input. The energy storage system is a core of energy interaction. Therefore, in addition to complying with national standards, the energy storage system is also mandatorily required to have a black-start function. To be specific, in the off-grid mode, the energy storage system can be converted into a power supply with an independent power output, to supply power to important devices.
Currently, a common black-start manner is to dispose an uninterruptible power supply (UPS). The UPS is separately connected to a power grid and the energy storage system, and is configured to: before the power grid is powered off, store electric energy transmitted on the power grid; and when the power grid is powered off, provide the electric energy stored in the UPS to a control device in the energy storage system. After a power supply is restored, the control device controls the energy storage system to be started and re-output the stored electric energy to the power grid or a load, to implement a black start. The energy storage system includes a plurality of energy storage cabinets. In the foregoing black-start manner, the UPS needs to be connected to each energy storage cabinet through a cable. However, a cable connection between the UPS and the energy storage cabinet needs to be manually performed, and a cable connection error rate is high. As a result, the energy storage cabinet cannot be normally started.
Embodiments provide an energy storage cabinet and an energy storage system to improve black-start reliability of the energy storage cabinet.
According to a first aspect, an embodiment provides an energy storage cabinet. The energy storage cabinet is used in an energy storage system. A single energy storage cabinet includes a battery rack and a power conversion system.
The battery rack includes a battery unit, a switch unit, and a start unit; the battery unit includes a plurality of energy storage batteries connected in series; the switch unit is connected between the battery unit and the power conversion system; a first end of the power conversion system is configured to be connected to a bus in an energy storage system to which the energy storage cabinet belongs; when a voltage at the first end of the power conversion system is greater than a first preset voltage, the power conversion system is configured to: convert the voltage at the first end of the power conversion system into a target voltage, and supply power to the start unit through a second end of the power conversion system; and the start unit is configured to: when the power supplied by the power conversion system is received, control the switch unit to be turned on, so that the battery unit is connected to the power conversion system.
When a power grid is powered off or the energy storage cabinet is installed for the first time, the energy storage cabinet needs to be started to form a connection to the power grid or a load. Because first ends of power conversion systems in a plurality of energy storage cabinets are configured to be connected to the bus, after another energy storage cabinet in the system is successfully started, electric energy exists on the bus, and the electric energy also exists at the first end of the power conversion system in the to-be-started energy storage cabinet. Therefore, the to-be-started energy storage cabinet may obtain the electric energy from the first end of the power conversion system, convert the obtained electric energy into the target voltage required for starting operating. After obtaining the electric energy, the start unit controls the switch unit to be turned on, to normally start the energy storage cabinet. In this way, black-start reliability of the energy storage cabinet is improved.
In a possible implementation, the start unit is further configured to: receive power supplied by the battery unit or an alternating current power supply, and control the switch unit to be turned on.
In an embodiment, an externally disposed uninterruptible power supply UPS may be used as an external alternating current power supply connected to the energy storage cabinet. If a cable connection between the energy storage cabinet and the UPS is correct and the UPS is normal, the start unit in the energy storage cabinet may obtain electric energy required for power supply from the UPS, and control the switch unit to be turned on, to start the energy storage cabinet. If the cable connection between the UPS and the energy storage cabinet is incorrect or the UPS is faulty, the start unit may alternatively obtain electric energy required for power supply from the battery unit in the energy storage cabinet, and control the switch unit to be turned on, to start the energy storage cabinet.
In a possible implementation, the start unit includes a first power supply circuit and a control circuit.
The first power supply circuit is connected between the second end of the power conversion system and the control circuit, and is configured to: when the power supplied by the power conversion system is received, supply the power to the control circuit; and the control circuit is connected to the switch unit, and is configured to: when the power supplied by the first power supply circuit is received, control the switch unit to be turned on.
In an embodiment, the first power supply circuit uses the power conversion system as a power supply. When the started energy storage cabinet exists in the energy storage system, the power conversion system in the to-be-started energy storage cabinet may obtain electric energy from the started energy storage cabinet through the first end, and supply power to the control circuit through the second end by using the obtained electric energy, to control the switch unit to be turned on, so as to normally start the energy storage cabinet and ensure start reliability of the energy storage cabinet.
In a possible implementation, the first power supply circuit includes a first auxiliary power supply. A first input end of the first auxiliary power supply is connected to a positive electrode of the second end of the power conversion system, a second input end of the first auxiliary power supply is connected to a negative electrode of the second end of the power conversion system, and an output end of the first auxiliary power supply is connected to the control circuit. The positive electrode of the second end of the power conversion system may be an interface for outputting a high level by the power conversion system, and the negative electrode of the second end of the power conversion system may be an interface for outputting a low level by the power conversion system.
In an embodiment, when the started energy storage cabinet exists in the energy storage system, the power conversion system in the to-be-started energy storage cabinet may obtain, through the first end, the electric energy output by the started energy storage cabinet, perform voltage regulation or other processing on the received electric energy, and then supply power to the first auxiliary power supply through the second end of the power conversion system. After obtaining the power, the first auxiliary power supply supplies the power to the control circuit, to control the switch unit to be turned on, so as to start the energy storage cabinet.
In a possible implementation, the first power supply circuit further includes: a first diode connected between the positive electrode of the second end of the power conversion system and the first input end of the first auxiliary power supply, and a second diode connected between the negative electrode of the second end of the power conversion system and the second input end of the first auxiliary power supply.
In an embodiment, the first diode and the second diode may be used to control a flow direction of a current in a process in which the power conversion system supplies the power to the start unit.
In a possible implementation, the first power supply circuit further includes a first switch and a second switch.
The first switch and the second switch are connected in parallel between the first input end of the first auxiliary power supply and a positive electrode of the battery unit; the second input end of the first auxiliary power supply is further connected to a negative electrode of the battery unit; when the first switch is turned on, the first power supply circuit receives the power supplied by the battery unit; and the second switch is configured to be turned on when the first switch is turned off, so that the first power supply circuit receives the power supplied by the battery unit.
In an embodiment, the first switch is turned on after receiving a drive signal, and the first switch is turned on to form an electric energy transmission path between the battery unit and the first auxiliary power supply. The battery unit may supply the power to the first auxiliary power supply. After obtaining the power, the first auxiliary power supply supplies power to the control circuit, so that the switch unit is turned on, to start the energy storage cabinet.
In a possible implementation, the first power supply circuit further includes: a third diode connected between the second switch and the positive electrode of the battery unit, and a fourth diode connected between the second input end of the first auxiliary power supply and the negative electrode of the battery unit.
In an embodiment, the third diode and the fourth diode may be used to control a flow direction of a current in a process in which the battery unit supplies the power to the first auxiliary power supply.
In a possible implementation, the start unit further includes a second power supply circuit. The second power supply circuit is connected to the control circuit and the alternating current power supply, and is configured to: receive the power supplied by the alternating current power supply, and supply the power to the control circuit. The control circuit is further configured to: when the power supplied by the second power supply circuit is received, control the switch unit to be turned on.
In an embodiment, the second power supply circuit uses the alternating current power supply as a power supply. When the external alternating current power supply is normal and the cable connection between the external alternating current power supply and the energy storage cabinet is correct, the external alternating current power supply may provide electric energy required for starting the start unit, to normally start the energy storage cabinet. In addition, because the first power supply circuit and the second power supply circuit operate independently, black-start reliability can be ensured.
In a possible implementation, the second power supply circuit includes a second auxiliary power supply, an input end of the second auxiliary power supply is configured to be connected to the alternating current power supply, and an output end of the second auxiliary power supply is connected to the control circuit.
In an embodiment, the second auxiliary power supply may obtain electric energy from the external alternating current power supply, and supply power to the control circuit. After obtaining the power, the control circuit may control the switch unit to be turned on, to implement black start of the energy storage cabinet.
In a possible implementation, the start unit is configured to: when an output voltage of the alternating current power supply is greater than a second preset voltage, receive the power supplied by the alternating current power supply.
In an embodiment, a minimum voltage required by the second auxiliary power supply for operating may be set to the second preset voltage. When the output voltage of the external alternating current power supply is greater than the second preset voltage, the voltage output by the external alternating current power supply may meet a requirement of the second auxiliary power supply for a power supply voltage.
In a possible implementation, the second power supply circuit further includes: a third switch connected between the alternating current power supply and a first input end of the second auxiliary power supply, and a fourth switch connected between the alternating current power supply and a second input end of the second auxiliary power supply. When the third switch and the fourth switch are turned on, the second power supply circuit receives the power supplied by the alternating current power supply.
In an embodiment, the third switch and the fourth switch are turned on after receiving a drive signal, and the third switch and the fourth switch form an electric energy transmission path between the alternating current power supply and the second auxiliary power supply. The second auxiliary power supply may obtain the electric energy from the external alternating current power supply, and supply the power to the control circuit. After obtaining the power, the control circuit controls the switch unit to be turned on, to implement black start of the energy storage cabinet.
In a possible implementation, the switch unit includes a fifth switch and a sixth switch.
The fifth switch is connected between the positive electrode of the battery unit and the positive electrode of the second end of the power conversion system, and the sixth switch is connected between the negative electrode of the battery unit and the negative electrode of the second end of the power conversion system.
In a possible implementation, the battery rack further includes an undervoltage protection circuit, and an action voltage of the undervoltage protection circuit may be set based on a quantity of energy storage batteries in the battery unit.
In an embodiment, with use of the energy storage cabinet or maintenance of the energy storage cabinet, the quantity of energy storage batteries in the battery unit may change. To implement safety protection of the energy storage cabinet, the undervoltage protection circuit may be disposed in the battery rack, and the action voltage of the undervoltage protection circuit may be set based on the quantity of energy storage batteries in the battery unit, to protect the energy storage cabinet.
According to a second aspect, an embodiment provides an energy storage system. The energy storage system includes a plurality of energy storage cabinets according to any possible implementation or design of the first aspect and a bus, and a first end of a power conversion system in each energy storage cabinet is connected to the bus.
In a possible implementation, a power conversion system in at least one energy storage cabinet is a DC/DC converter, the energy storage system further includes a DC/AC converter, and the DC/DC converter is connected to the DC/AC converter.
According to a third aspect, an embodiment provides a photovoltaic system. The photovoltaic system includes a plurality of photovoltaic modules, a DC/DC converter, a DC/AC converter, and the energy storage system according to any possible implementation or design of the second aspect.
The plurality of photovoltaic modules are connected to the DC/DC converter, and the plurality of photovoltaic modules are configured to convert light energy into a first direct current, and output the first direct current to the DC/DC converter. The DC/DC converter is connected to the DC/AC converter, and the DC/DC converter is configured to convert the first direct current into a second direct current, and output the second direct current to the DC/AC converter. The DC/AC converter is connected to the energy storage system, and is configured to convert the second direct current into an alternating current, and output the alternating current to a power-consuming device or the energy storage system. The energy storage system is configured to convert the alternating current into a third direct current and store the third direct current, or convert stored electric energy into the alternating current and output the alternating current to the power-consuming device.
According to a fourth aspect, an embodiment provides a power supply system. The power supply system includes: an alternating current power supply, at least one power-consuming device, and the energy storage system according to any possible implementation or design of the second aspect.
The alternating current power supply is connected to a part of or all energy storage cabinets in the energy storage system, and is configured to obtain electric energy from a power grid and supply power to the part of or all energy storage cabinets in the energy storage system. The energy storage system is connected to the at least one power-consuming device, and is configured to obtain electric energy from the power grid and store the electric energy, or use stored electric energy to supply power to the at least one power-consuming device.
For effects that can be achieved by any possible implementation or design of any one of the second aspect to the fourth aspect, refer to descriptions of effects that can be achieved by any possible implementation or design of the first aspect. Details are not described herein.
The following describes in detail embodiments with reference to the accompanying drawings.
To make objectives, solutions, and advantages clearer, the following further describes the embodiments in detail with reference to the accompanying drawings. A specific operation method in a method embodiment may also be applied to an apparatus embodiment or a system embodiment. It should be noted that, in the descriptions of the embodiments, “a plurality” refers to two or more. In view of this, in embodiments, “a plurality of” may also be understood as “at least two”. In addition, it should be understood that, in the descriptions of the embodiments, terms such as “first” and “second” are merely used for distinguishing and description, cannot be understood as an indication or implication of relative importance, and cannot be understood as an indication or implication of a sequence.
It should be noted that a “connection” in embodiments refers to an electrical connection, and a connection between two electrical elements may be a direct or indirect connection between the two electrical elements. For example, that A is connected to B may be that A is directly connected to B, or may be that A is indirectly connected to B through one or more other electrical elements. For example, that A is connected to B may alternatively be that A is directly connected to C, C is directly connected to B, A and B are connected through C.
It should be noted that a switch in embodiments may be one or more of a plurality of types of switch devices, such as a relay, a metal-oxide semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), or a silicon carbide (SiC) power transistor. The switch devices are not listed one by one in embodiments. Each switch device may include a first electrode (a first end), a second electrode (a second end), and a control electrode (a control end), and the control electrode is configured to control turning on or turning off of the switch. When the switch is turned on, a current may be transmitted between the first electrode and the second electrode of the switch. When the switch is turned off, a current cannot be transmitted between the first electrode and the second electrode of the switch. The MOSFET is used as an example. The control electrode of the switch is a gate. The first electrode of the switch may be a source of the switch, and the second electrode may be a drain of the switch. Alternatively, the first electrode may be a drain of the switch, and the second electrode may be a source of the switch.
The following clearly and completely describes the solutions in embodiments with reference to the accompanying drawings. The solutions provided in embodiments are applied to a large power supply device or a new energy system in which an energy storage cabinet is internally configured as a backup power supply. The new energy system includes, but is not limited to, a photovoltaic system, a wind power system, and a hydraulic system. The power supply device includes, but is not limited to, an industrial device, a smart factory device, and the like.
The following uses an example in which the new energy system is a photovoltaic system.
The plurality of photovoltaic modules are connected to the DC/DC converter; and the plurality of photovoltaic modules may convert light energy into a first direct current, and output the first direct current to the DC/DC converter. The DC/DC converter is connected to the DC/AC converter, and the DC/DC converter may convert the received first direct current into a second direct current. The DC/AC converter is connected to the power grid or the load; and the DC/AC converter may convert the received direct current into an alternating current, and output the alternating current to the power grid or the load. The energy storage system is connected to the DC/AC converter; and the energy storage system may store redundant electric energy when electric energy output by the DC/AC converter exceeds an electric energy requirement of the power grid or the load, and output the stored electric energy to the power grid or the load when the electric energy output by the DC/AC converter is less than the electric energy requirement.
In actual application, the photovoltaic system shown in
It should be understood that a connection relationship between the photovoltaic system and the power grid in
In a possible implementation, a direct current energy storage battery is used in the energy storage system to store energy. A voltage of the direct current output by the DC/AC converter fluctuates greatly, and a voltage value of the output direct current cannot meet a voltage requirement of the energy storage system. Therefore, a power conversion system may be further configured in the energy storage system. The power conversion system may perform rectification and voltage regulation on the alternating current output by the DC/AC converter, to output a direct current voltage available to the energy storage battery in the energy storage system.
In actual application, when the connected power grid or load is powered off due to a fault, periodic maintenance, initial installation of the energy storage system, or the like, the energy storage system needs to be used as an independent power supply to supply power to the load or the power grid. In other words, a black start is performed.
Currently, a common black-start manner is to dispose an uninterruptible power supply (UPS) in the photovoltaic system. As shown in
In actual application, a plurality of energy storage cabinets can be configured in the energy storage system, to implement high power supplying or output electric energy to the power grid or the load. In the black start manner, the UPS needs to be connected to each energy storage cabinet. A cable connection in this part can be performed manually, and a cable connection error rate is high. As a result, the energy storage system cannot be normally started.
In view of this, the embodiments provide an energy storage cabinet and an energy storage system. The energy storage cabinet may be used in the photovoltaic system shown in
As shown in
The following describes a structure of the energy storage cabinet in detail with reference to embodiments.
For example, the battery unit includes a plurality of energy storage batteries connected in series, a first end of the switch unit is connected to the battery unit, and a second end of the switch unit is connected to a second end of the power conversion system. When the switch unit is turned on, the battery unit is connected to the second end of the power conversion system. If the switch unit is turned off, the battery unit is disconnected from the second end of the power conversion system. A first end of the power conversion system may be connected to an electric energy output port of the energy storage cabinet. Therefore, the energy storage cabinet may be connected to a bus in an energy storage system to which the energy storage cabinet belongs through the first end of the power conversion system. The power conversion system is configured to: when a voltage at the first end of the power conversion system is greater than a first preset voltage, convert the voltage at the first end of the power conversion system into a target voltage, and supply power to the start unit by using the target voltage through the second end of the power conversion system. The start unit is connected to the second end of the power conversion system and the switch unit, and is configured to: when the power supplied by the power conversion system is received, control the switch unit to be turned on, so that the battery unit is connected to the power conversion system. The target voltage may be a rated voltage of the battery unit, or may be a power supply voltage of the start unit.
In an actual application scenario, the energy storage cabinet may be fastened on the energy storage system. Alternatively, the energy storage cabinet may be in a flexible and detachable form. For example, a fixed interface is disposed on the energy storage system, and the energy storage cabinet may be connected to another energy storage cabinet in the energy storage system through the fixed interface. In this case, the energy storage cabinet may be considered as an apparatus independent of the energy storage system.
For example, electric energy output ports of a plurality of energy storage cabinets in the energy storage system are connected together, and the first end of the power conversion system in the energy storage cabinet is connected to the electric energy output port of the energy storage cabinet. Therefore, when any energy storage cabinet in the energy storage system is normally started, electric energy exists on the bus, and the electric energy exists on a first end of a power conversion system in each energy storage cabinet. The power conversion system may not only process a direct current output by the battery unit and output the direct current to another energy storage cabinet and a power-consuming device through the first end of the power conversion system, but also process electric energy at the first end of the power conversion system and output the electric energy to the start unit through the second end of the power conversion system. Therefore, a power conversion system in a to-be-started energy storage cabinet may process electric energy output by another energy storage cabinet, and output the electric energy to a start unit through a second end of the power conversion system. The start unit may operate by using the electric energy output by the power conversion system and control a switch unit to be turned on. In this case, a battery unit is connected to the power conversion system, and may output the stored electric energy to the power-consuming device through the power conversion system, to start the energy storage cabinet. The first preset voltage may be a minimum voltage value of the first end when the power conversion system normally operates.
In actual application, the plurality of energy storage cabinets in the energy storage system may be connected to a direct current bus or an alternating current bus through first ends of power conversion systems. After one or more energy storage cabinets in the energy storage system are started, a voltage is generated on the direct current bus or the alternating current bus. When it is detected that the voltage on the direct current bus or the alternating current bus is greater than the first preset voltage, it is determined that an energy storage cabinet in the energy storage system is successfully started, and an energy storage cabinet that is not started may obtain electric energy from the alternating current bus or the direct current bus through a first end of a power conversion system, process the obtained electric energy, and then supply the electric energy to a start unit through a second end of the power conversion system. After receiving the electric energy, the start unit may control a switch unit to be turned on, to start the energy storage cabinet.
It can be understood from the foregoing descriptions that the power conversion system is a bidirectional conversion device. When the electric energy is transmitted from the first end of the power conversion system to the second end of the power conversion system, the first end of the power conversion system is used as an input end of the power conversion system to receive the electric energy, and the second end of the power conversion system is used as an output end of the power conversion system to output the electric energy. When the electric energy is transmitted from the second end of the power conversion system to the first end of the power conversion system, the second end of the power conversion system is used as an input end of the power conversion system to receive the electric energy, and the first end of the power conversion system is used as an output end of the power conversion system to output the electric energy.
The following describes a starting manner of the energy storage cabinet with reference to specific structures of the battery rack and the power conversion system in the energy storage cabinet.
A plurality of energy storage batteries may be disposed in the battery unit in the battery rack; and each energy storage battery may be a storage battery, or may be a storage battery cluster including a plurality of storage batteries. The energy storage battery may be a secondary battery or an energy storage capacitor. The secondary battery includes, but is not limited to, a lithium-ion battery, a sodium-ion battery, a potassium-ion battery, a magnesium-ion battery, a calcium-ion battery, an air battery, a lead-acid battery, a nickel-cadmium battery, and the like. A specific type of the secondary battery is not limited, provided that the battery can implement charging and discharging.
In an example, the plurality of energy storage batteries may be connected in series, a positive electrode of a first energy storage battery in the plurality of energy storage batteries is a positive electrode of the battery unit, and a negative electrode of a last energy storage battery in the plurality of energy storage batteries is a negative electrode of the battery unit.
In another example, the plurality of energy storage batteries may be connected in parallel, positive electrodes of the plurality of energy storage batteries are connected and used as a positive electrode of the battery unit, and negative electrodes of the plurality of energy storage batteries are connected and used as a negative electrode of the battery unit.
The start unit in the battery rack is connected to the switch unit, and the start unit may control the switch unit to be turned on or turned off. When the switch unit is turned on, the battery unit is connected to the second end of the power conversion system, and the power conversion system may process the electric energy stored in the battery unit and output the electric energy to the power-consuming device, to start the energy storage cabinet. When the switch unit is turned off, the battery unit is disconnected from the second end of the power conversion system.
In actual application, when the energy storage cabinet is installed for the first time or the power grid is powered off, the start unit may obtain electric energy output by another energy storage cabinet through the power conversion system, and operate by using the electric energy, to control the switch unit to be turned on, so as to start the energy storage cabinet.
The second end of the power conversion system is connected to the battery unit through the switch unit, and the first end of the power conversion system is connected to the bus in the energy storage system and the power-consuming device. The power conversion system may have one or more of a voltage regulation function, an inversion function, and a rectification function.
In a possible implementation, when a voltage amplitude of the second end of the power conversion system can meet a voltage requirement of a first end connection device, only a DC/AC converter may be disposed in the power conversion system, and the DC/AC converter is disposed between the first end and the second end of the power conversion system. The DC/AC converter may invert the electric energy output by the battery unit, and then output the electric energy to the power-consuming device or the bus through the first end of the power conversion system; or rectify the voltage received by the first end of the power conversion system, and then output the voltage to the start unit through the second end of the power conversion system.
In another possible implementation, when a voltage amplitude of the second end of the power conversion system cannot meet a voltage requirement of a first end connection device, a DC/DC converter may be disposed in the power conversion system, and the DC/DC converter is connected between the first end and the second end of the power conversion system. The DC/DC converter may perform voltage regulation on the electric energy output by the battery unit, and then output the electric energy to the power-consuming device or the bus through the first end of the power conversion system; or perform voltage regulation on the voltage received by the first end of the power conversion system, and then output the voltage to the start unit through the second end of the power conversion system.
In an example, because the energy storage system can be configured to supply power to the power grid or an alternating current load, a DC/AC converter connected between the DC/DC converter and the first end of the power conversion system may be further disposed in the power conversion system. The DC/AC converter may convert the direct current output by the DC/DC converter into an alternating current, to supply power to the power grid or the alternating current load.
In another example, to reduce a quantity and costs of devices in the energy storage system, the first end of the power conversion system is connected to the DC/AC converter. In other words, DC/DC converters in all the energy storage cabinets share one DC/AC converter.
The following describes in detail, with reference to embodiments, a process in which the start unit obtains electric energy from another started energy storage cabinet through the power conversion system and uses the obtained electric energy to control starting of the energy storage cabinet.
For example, as shown in
When the first power supply circuit shown in
In a possible implementation, as shown in
In the foregoing embodiment, the start unit uses the electric energy output by the another energy storage cabinet to control the switch unit to be turned on, to implement the process of starting the energy storage cabinet. In actual application, as shown in
In an example, as shown in
In another example, as shown in
The following describes in detail, with reference to embodiments, a process in which the start unit controls the switch unit to be turned on by using the electric energy of the UPS or the battery unit.
As shown in
The first switch K1 may be a mechanical switch. For example, the first switch K1 may be a button switch shown in
When the first power supply circuit shown in
In actual application, if the first switch K1 is a button switch, when the first switch K1 pops up, the first auxiliary power supply is disconnected from the battery unit. To ensure that the first auxiliary power supply can obtain power for a long time, after obtaining power from the first auxiliary power supply, the control circuit may send, to a control end of the second switch K2, a drive signal used to control the second switch K2 to be turned on, to control the second switch K2 to be in a turned-on state for a long time. Therefore, when the first switch K1 pops up and is in a turned-off state, the second switch K2 is still in the turned-on state, and maintains a connection between the battery unit and the first auxiliary power supply, so that the first power supply circuit receives the power supplied by the battery unit.
In a possible implementation, as shown in
In a possible implementation, a switch device is connected to the UPS side. When the switch device is turned on, an electric energy transmission path is formed between the UPS and the second auxiliary power supply. The UPS outputs the stored electric energy to the second auxiliary power supply, and a voltage received by the second auxiliary power supply is greater than the second preset voltage. Therefore, when it is detected that the output voltage on the UPS side is greater than the second preset voltage, the second power supply circuit may receive the power supplied by the UPS.
In another possible implementation, as shown in
It should be noted that a quantity of switches disposed between the UPS and the second auxiliary power supply in the second power supply circuit is not limited in embodiments. Alternatively, only one switch may be disposed. For example, a branch in which the fourth switch is located in
With reference to the foregoing descriptions, it can be understood that when the cable connection between the external alternating current power supply UPS and the energy storage cabinet is normal, the UPS may supply power to the second auxiliary power supply. After obtaining the power, the second auxiliary power supply supplies the power to the control circuit. The control circuit may control the switch unit to be turned on by sending a control signal to the switch in the switch unit, to implement black start of the energy storage cabinet. When the cable connection between the external alternating current power supply UPS and the energy storage cabinet is incorrect, the first switch K1 is pressed, so that the battery unit supplies power to the first auxiliary power supply. After obtaining the power, the first auxiliary power supply may supply the power to the control circuit. The control circuit may control the switch unit to be turned on by sending a control signal to the switch in the switch unit, to implement black start of the energy storage cabinet.
In a specific implementation, as shown in
As shown in
It should be noted that a quantity of switches disposed in the switch unit is not limited in embodiments. Alternatively, only one switch may be disposed. For example, a branch in which the sixth switch is located in
When the battery unit in the energy storage cabinet is faulty, an energy storage battery in the battery unit may be replaced, causing a change in the quantity of energy storage batteries in the battery unit. The undervoltage protection circuit and the overvoltage protection circuit in the energy storage cabinet may be configured based on the quantity of energy storage batteries in the battery unit.
Based on a same concept, an embodiment further provides an energy storage system. As shown in
In an example, the energy storage system may further include a battery management system (BMS). The BMS is connected to all the energy storage cabinets, and is configured to monitor a running status of each energy storage cabinet in the energy storage system. The running status may be a start state and a remaining capacity. Monitoring of the running status may be implemented by detecting parameters such as a current, a voltage, and power of each energy storage cabinet.
For example, the plurality of energy storage cabinets are connected in parallel to a power-consuming device, and are configured to output stored electric energy to the power-consuming device. In addition, because the plurality of energy storage cabinets are connected in parallel, electric energy output by each energy storage cabinet may be transmitted to the bus. The power-consuming device may be a power grid or a load. The following uses an example in which the power-consuming device is the power grid for description.
In a possible implementation, the energy storage system may include N energy storage cabinets, where some energy storage cabinets are the foregoing energy storage cabinets, and the remaining energy storage cabinets are in an existing energy storage cabinet architecture. N is a positive integer greater than or equal to 2.
In another possible implementation, the energy storage system may include N energy storage cabinets, and the N energy storage cabinets are all the foregoing energy storage cabinets.
In an example, as shown in
In another example, a single energy storage cabinet may obtain electric energy from a started energy storage cabinet and implement starting. Therefore, to avoid a cable connection error, as shown in
In a possible implementation, as shown in
In a possible implementation, when a voltage amplitude output by a battery unit can meet a voltage amplitude requirement of the power-consuming device, as shown in
In a possible implementation, as shown in
It should be understood that, in
Based on a same concept, an embodiment provides a photovoltaic system. As shown in
The plurality of photovoltaic modules are connected to the DC/DC converter, and the plurality of photovoltaic modules are configured to convert light energy into a first direct current, and output the first direct current to the DC/DC converter. The DC/DC converter is connected to the DC/AC converter, and the DC/DC converter is configured to convert the first direct current into a second direct current, and output the second direct current to the DC/AC converter. The DC/AC converter is connected to the energy storage system, and is configured to convert the second direct current into an alternating current, and output the alternating current to a power-consuming device or the energy storage system. The energy storage system is configured to convert the alternating current into a third direct current and store the third direct current, or convert stored electric energy into the alternating current and output the alternating current to the power-consuming device.
Optionally, as shown in
Based on a same concept, an embodiment provides a power supply system. The power supply system includes an alternating current power supply, at least one power-consuming device, and the foregoing energy storage system. The alternating current power supply may be an uninterruptible power supply UPS.
The UPS is connected to a part of or all energy storage cabinets in the energy storage system, and is configured to obtain electric energy from a power grid and supply power to the part of or all energy storage cabinets in the energy storage system. The energy storage system is connected to the at least one power-consuming device, and is configured to obtain electric energy from the power grid and store the electric energy, or use stored electric energy to supply power to the at least one power-consuming device.
It is clear that a person skilled in the art can make various modifications and variations to embodiments without departing from their scope. The embodiments are intended to cover these modifications and variations, as well as their equivalent technologies.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310308879.5 | Mar 2023 | CN | national |
This application is a continuation of International Application No. PCT/CN2024/079440, filed on Feb. 29, 2024, which claims priority to Chinese Patent Application 202310308879.5, filed on Mar. 21, 2023. The disclosures of the aforementioned applications are hereby incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2024/079440 | Feb 2024 | WO |
| Child | 18971290 | US |
