Energy storage system, energy storage system power supply device and driving power supply thereof

Abstract

The utility model provides an energy storage system, an energy storage system power supply device and a driving power supply thereof, and relates to the technical field of energy storage systems. According to the driving power supply of the power supply device of the energy storage system, the power conversion circuit is a single-stage power conversion circuit, that is, power can be supplied to corresponding auxiliary equipment in the energy storage system only through one-stage power conversion, so that the power utilization efficiency can be improved, the power supply energy consumption of the auxiliary equipment can be reduced, and the use cost of the driving power supply can be further reduced; moreover, compared with a two-stage conversion structure, the driving power supply provided by the utility model adopts a single-stage power conversion circuit, so that the manufacturing cost is lower. Besides, a distribution transformer in the prior art can be omitted, so that the structural complexity of the energy storage system can be reduced, and the system cost can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage systems, and more specifically, to an energy storage system, an energy storage system power supply device, and a driving power supply thereof. Background Art

[0002] At present, the battery stack in the energy storage system is generally connected to the power grid through PCS (Power Conversion System) and step-up transformer. In addition, some auxiliary equipment is also set up in the energy storage system to perform corresponding work. The power supply scheme of these auxiliary equipment is usually to draw power from the low-voltage winding of the step-up transformer, and then realize auxiliary power supply after power conversion through the corresponding driving power supply.

[0003] For auxiliary equipment using AC motors, the applicable drive power supply usually needs to adopt AC / DC / AC conversion topology for two-stage power conversion. Therefore, the current auxiliary power supply scheme of energy storage system has the problems of low power efficiency, high energy consumption and high cost. Utility Model Content

[0004] In order to solve the above technical problems, the present application provides an energy storage system, an energy storage system power supply device and a driving power supply thereof. The present application can improve the power efficiency of the auxiliary power supply of the energy storage system, reduce the power supply energy consumption of the auxiliary equipment, and thus reduce the manufacturing and use costs of the driving power supply.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] The first aspect of the present application provides a driving power supply for an energy storage system power supply device, comprising: a power conversion circuit; wherein:

[0007] The power conversion circuit is a single-stage power conversion circuit;

[0008] The input end of the power conversion circuit serves as the input end of the driving power supply;

[0009] The output end of the power conversion circuit, as the output end of the driving power supply, is connected to the power supply end of the corresponding auxiliary equipment in the energy storage system.

[0010] In a possible implementation, the input end of the driving power supply is connected to the DC side of the energy storage converter PCS in the energy storage system.

[0011] In a possible implementation, when the energy storage system is started, the input end of the driving power supply draws power from a slow-start circuit inside a battery stack in the energy storage system through a DC side of the PCS.

[0012] In a possible implementation, when the energy storage system is started, the input end of the driving power supply draws power from the output end of the soft start circuit in the energy storage system;

[0013] The input end of the soft start circuit is connected to the AC side of the PCS;

[0014] The output end of the soft-start circuit is connected to the DC side of the PCS.

[0015] In a possible implementation, the input end of the driving power supply takes power from the DC side of the AC / DC converter;

[0016] The AC side of the AC / DC converter receives AC power supply energy outside the energy storage system.

[0017] In a possible implementation, the power supply end of the auxiliary device receives alternating current power, and the power conversion circuit is a DC / AC conversion circuit.

[0018] In a possible implementation, the power supply end of the auxiliary device receives direct current power, and the power conversion circuit is a DC / DC conversion circuit.

[0019] A second aspect of the present application provides an energy storage system power supply device, comprising: at least one driving power supply of the energy storage system power supply device as described in the first aspect or any one of the implementation forms of the first aspect; wherein:

[0020] The output end of the driving power supply is connected to the power supply end of the corresponding auxiliary equipment in the energy storage system;

[0021] When the number of the driving power supplies is greater than 1, the input ends of the driving power supplies are connected in parallel.

[0022] In a possible implementation, the energy storage system power supply device further includes: an AC / DC converter;

[0023] The AC side of the AC / DC converter receives AC power supply energy outside the energy storage system;

[0024] The DC side of the AC / DC converter is connected to the input end of the driving power supply.

[0025] The third aspect of the present application provides an energy storage system, comprising: a battery stack, a PCS, a transformer, at least one auxiliary device, and an energy storage system power supply device as described in the second aspect or any one of the implementation forms of the second aspect; wherein,

[0026] The battery stack is connected to the DC side of the PCS;

[0027] The AC side of the PCS is connected to the primary winding of the transformer;

[0028] The secondary winding of the transformer is used to connect to a power grid and / or a load.

[0029] In a possible implementation, the energy storage system further includes: a soft start circuit;

[0030] The input end of the soft start circuit is connected to the AC side of the PCS;

[0031] The output end of the soft-start circuit is connected to the DC side of the PCS.

[0032] In a possible implementation, each of the auxiliary devices includes at least one of the following:

[0033] A cooling unit for regulating the temperature of the battery stack;

[0034] Exhaust fans for fire safety;

[0035] A cooling fan of the PCS;

[0036] A sub-controller of the PCS.

[0037] It can be seen from the above technical solution that the driving power supply of the energy storage system power supply device provided by the present application has a power conversion circuit that is a single-stage power conversion circuit, that is, the corresponding auxiliary equipment in the energy storage system can be powered by only one stage of power conversion, which can improve power efficiency and reduce the power supply energy consumption of the auxiliary equipment, thereby reducing the use cost of the driving power supply; moreover, compared with the two-stage conversion structure, the driving power supply provided by the present application adopts a single-stage power conversion circuit, and its manufacturing cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 It is a schematic diagram of the power supply principle of auxiliary equipment of the energy storage system in the prior art;

[0040] Figure 2 It is a structural schematic diagram of an energy storage system and an energy storage system power supply device provided in an embodiment of the present application;

[0041] Figure 3 It is another structural schematic diagram of the energy storage system and the energy storage system power supply device provided in the embodiment of the present application;

[0042] Figure 4It is another structural schematic diagram of the energy storage system and the energy storage system power supply device provided in the embodiment of the present application;

[0043] Figure 5 It is a schematic diagram of the internal structure of the battery stack provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0045] refer to Figure 1 At present, there are many auxiliary devices in the energy storage system, such as cooling units for regulating the temperature of the battery stack, exhaust fans for fire safety, and cooling fans and sub-controllers for cooling the PCS. Figure 1 The three auxiliary devices, cooling unit, exhaust fan and heat dissipation fan, are used as examples for explanation). The system that supplies power to these auxiliary devices usually has a large capacity, for example, it will be greater than 1% of the capacity of the power station where the system is located; moreover, auxiliary devices such as cooling unit and exhaust fan generally use AC motors, so corresponding drive power supplies are required. These drive power supplies usually use AC / DC / AC conversion topology for two-stage power conversion, which has low comprehensive power efficiency and high energy consumption. Not only is the cost of use high, but the manufacturing cost itself is also high.

[0046] Based on this, the present application provides a driving power supply for an energy storage system power supply device to improve the power efficiency of the auxiliary power supply of the energy storage system, reduce the power supply energy consumption for auxiliary equipment, and thereby reduce the manufacturing and use costs of the driving power supply.

[0047] The driving power supply of the power supply device of the energy storage system includes: a power conversion circuit; an input end of the power conversion circuit, which serves as an input end of the driving power supply; and an output end of the power conversion circuit, which serves as an output end of the driving power supply and is connected to a power supply end of a corresponding auxiliary device in the energy storage system.

[0048] Moreover, the power conversion circuit is a single-stage power conversion circuit, for example, see Figure 2For auxiliary equipment such as cooling units and exhaust fans that need to receive AC power, the power conversion circuit in the driving power supply 201 can be a DC / AC conversion circuit to perform variable frequency speed regulation on the corresponding motor; the specific topology of the DC / AC conversion circuit is not limited, and any topology in the prior art can be selected according to the actual application environment; moreover, the DC / AC conversion circuit can adopt a new circuit structure other than the existing driving power supply, or can continue to use the DC / AC conversion part in the AC / DC / AC conversion topology in the existing driving power supply to be compatible with the existing driving power supply.

[0049] In addition, for auxiliary equipment that receives DC power, such as a DC small turbulence fan, a controller, etc., the power conversion circuit in the driving power supply 201 can be a DC / DC conversion circuit.

[0050] The driving power supply provided in this embodiment has a power conversion circuit that is a single-stage power conversion circuit, that is, the corresponding auxiliary equipment in the energy storage system can be powered by only one-stage power conversion, which can improve power efficiency, reduce power consumption of auxiliary equipment, and thus reduce the cost of using the driving power supply; moreover, compared with a two-stage conversion structure, the driving power supply provided in this embodiment adopts a single-stage power conversion circuit, and its manufacturing cost is lower.

[0051] Also, see Figure 1 The traditional driving power supply usually draws power from the low-voltage winding of the step-up transformer through an additional distribution transformer. This leads to the problem of complex structure of the energy storage system. At the same time, the existence of the distribution transformer will increase the system cost.

[0052] In order to solve this problem, this embodiment provides multiple optional forms for the power supply location of the driving power supply on the basis of the previous embodiment. For example, in the scenario where the use of local power supply is allowed, an internal power supply method can be adopted. In this case, a distribution transformer may not be configured, but the input end of the driving power supply 201 is connected to the DC side of the PCS12 (such as Figure 2 and Figure 3 In the scenario where local power supply is not allowed, an external power supply can be used. In this case, there is no need to configure a distribution transformer. The input end of the driving power supply 201 can be set to receive AC power supply outside the energy storage system through an AC / DC converter (as shown in Figure 4 Specific:

[0053] (1) See Figure 2 , a DC power supply interface is provided through the DC bus connected to the DC side of PCS12; moreover, when the energy storage system is started, the input end of the driving power supply 201 draws power from the slow-start circuit inside the battery stack 11 in the energy storage system through the DC bus, that is, the DC side of PCS12.

[0054] like Figure 5 As shown in the figure, the battery stack 11 includes: a battery module 101, an access switch module 102 and a slow-start circuit 103; wherein the battery module 101 includes one battery or multiple batteries connected in series and parallel; the access switch module 102 includes two switches respectively arranged in the positive and negative transmission branches, and the slow-start circuit 103 is connected in parallel with the switch in the positive transmission branch. Figure 3 This is only an exemplary display of the internal structure of the battery stack 11 and is not limited thereto. Other structures in the prior art are also within the protection scope of this application.

[0055] When the energy storage system is started, if the battery stack 11 is started first, the battery module 101 can first power the DC bus through the slow-start circuit 103, and when the voltage difference between the two sides of the access switch module 102 is small, the access switch module 102 is closed to complete the startup. During the startup process, the battery module 101 powers the DC bus through the slow-start circuit 103, so that the drive power supply 201 can be powered, and then the corresponding auxiliary equipment can be powered.

[0056] See also Figure 3 The energy storage system also includes a soft start circuit 14, the input end of which is connected to the AC side of the PCS 12, and the output end of which is connected to the DC side of the PCS 12. At this time, the DC power supply interface is still provided by the DC bus connected to the DC side of the PCS 12; however, unlike the above form (1), when the energy storage system is started, the input end of the driving power supply 201 draws power from the output end of the soft start circuit 14.

[0057] That is, when the energy storage system is started, if it is started from the AC side of PCS12, the configured soft start circuit 14 can be used to draw power from the AC side of PCS12, and the DC bus can be slowly started, so that PCS12 can be started safely. During the startup process, the soft start circuit 14 converts the grid power on the AC side of PCS12 to supply power to the DC bus, so that the drive power supply 201 can be powered, and then the corresponding auxiliary equipment can be powered.

[0058] In addition, for the above forms (1) and (2), after the energy storage system completes startup and enters the normal operation stage: if the battery stack 11 is discharged, the driving power supply 201 can directly receive part of the DC power provided by the battery module 101 when it is discharged by connecting to the switch module 102; if the battery stack 11 is charged, the driving power supply 201 can directly receive part of the AC power provided by the power grid through the PCS12.

[0059] It is worth mentioning that Figure 1In the prior art shown, since the loss of auxiliary power supply may continue to change and the closed-loop control speed of the system grid-connected power is slow, it is difficult to meet the 1% requirement for the response accuracy of the grid dispatching command. For the above forms (1) and (2), the loss of auxiliary power supply is automatically deducted from the DC bus, and the output power Ppcs of PCS12 is also the output power Pout of the energy storage system. Therefore, the set power Pset of PCS12 can be directly set to the command power of the grid dispatching command without adding the auxiliary power supply loss power Ploss on the AC side in the prior art. Therefore, the response accuracy of the grid dispatching command in this embodiment is more controllable. Moreover, in this case, the efficiency of the transformer 13 is relatively fixed, and the gain of the set power Pset can be appropriately matched.

[0060] (3) See Figure 4 (Taking the soft-start circuit 14 as an example for demonstration), the input end of the driving power supply 201 draws power from the DC side of the AC / DC converter 202; the AC side of the AC / DC converter 202 receives AC power supply energy outside the energy storage system.

[0061] The AC power supply energy may specifically refer to the AC power energy provided by a 400V or 480V (American standard) power supply line provided outside the energy storage system.

[0062] That is, in a scenario where the use of local power supply is not allowed, the AC power supply outside the energy storage system can be rectified and converted by the AC / DC converter 202 to supply power to the drive power supply 201; it should be noted that in the form of external power supply (3), although the AC / DC converter 202 is required to realize the power supply of the drive power supply 201, the drive power supply 201 can still use a single-stage power conversion circuit, that is, the manufacturing and use costs of the drive power supply can still be reduced. Moreover, in this form, the set power Pset of PCS12 also does not need to consider the auxiliary power supply loss power Ploss. Therefore, compared with the prior art, this form can also improve the response accuracy to the grid dispatching command.

[0063] The driving power supply 201 provided in this embodiment, regardless of which power supply form is adopted, can directly convert the received DC power by adopting a single-stage power conversion circuit, thereby omitting the Figure 1 The distribution transformer shown in can reduce the structural complexity of the energy storage system and reduce the system cost.

[0064] Another embodiment of the present application further provides an energy storage system power supply device 20, such as Figures 2 to 4As shown in , it includes: at least one driving power supply 201 as described in any of the above embodiments; wherein the output end of the driving power supply 201 is connected to the power supply end of the corresponding auxiliary equipment in the energy storage system; and when the number of driving power supplies 201 is greater than 1, the input ends of each driving power supply 201 are connected in parallel.

[0065] As described in the above embodiments, Figure 2 and Figure 3 As shown in the figure, the input end of the driving power supply 201 can be connected to the DC side of PCS12, and then during the system startup process, it can draw power from the soft-start circuit inside the battery stack 11 in the energy storage system, or it can also draw power from the output end of the soft-start circuit 14 in the energy storage system; it depends on the specific application environment, all of which are within the protection scope of this application.

[0066] Or, if Figure 4 As shown in , the energy storage system power supply device 20 may also include: an AC / DC converter 202; the AC side of the AC / DC converter 202 receives AC power supply energy outside the energy storage system; and the DC side of the AC / DC converter 202 is connected to the input end of the driving power supply 201.

[0067] In practical applications, a suitable power electronic converter can be selected according to the power demand of the auxiliary equipment connected to the driving power supply 201, that is, a corresponding power conversion topology can be adopted to implement its power conversion circuit. The description of other structures and working principles can be referred to the above embodiments, and will not be repeated here.

[0068] This embodiment no longer uses the low-voltage AC bus of the distribution transformer in the prior art, but instead uses a DC bus or AC / DC converter 202 for centralized power supply to auxiliary equipment. The system structure is relatively simple, the power supply efficiency is higher, and the cost is lower.

[0069] Another embodiment of the present application also provides an energy storage system, see Figures 2 to 4 , which comprises: a battery stack 11, a PCS 12, a transformer 13, at least one auxiliary device and an energy storage system power supply device 20 as described in any of the above embodiments; wherein:

[0070] The battery stack 11 is connected to the DC side of the PCS 12; the two may be specifically connected via a DC bus.

[0071] The AC side of the PCS 12 is connected to the primary winding of a transformer 13; the transformer 13 may be a step-up transformer.

[0072] The secondary winding of the transformer 13 is used to connect to a power grid and / or a load.

[0073] In practical applications, such as Figure 3 or Figure 4As shown in , the energy storage system may further include: a soft-start circuit 14; an input end of the soft-start circuit 14 is connected to the AC side of the PCS 12; and an output end of the soft-start circuit 14 is connected to the DC side of the PCS 12.

[0074] Each auxiliary device includes at least one of the following: a cooling unit for regulating the temperature of the battery stack 11, an exhaust fan for achieving fire safety, a heat dissipation fan of the PCS 12, and a sub-controller of the PCS 12. In practical applications, other auxiliary devices may also be included, which are only some optional examples and are not limited to these.

[0075] In this embodiment, the auxiliary power source provided by the low-voltage AC bus of the distribution transformer in the prior art is changed to a DC bus or AC / DC converter 202 to provide the auxiliary power source. The system structure is relatively simple, the power supply efficiency is higher, and the cost is lower.

[0076] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other. The modules and submodules in the devices and terminals of each embodiment of the present application can be merged, divided and deleted according to actual needs, and the features recorded in each embodiment can be replaced or combined.

[0077] In the several embodiments provided in the present application, it should be understood that the disclosed terminals and devices can be implemented in other ways. For example, the division of modules or submodules is only a logical function division, and there may be other division methods in actual implementation, such as multiple submodules or modules can be combined or integrated into another module, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0078] The modules or submodules described as separate components may or may not be physically separated, and the components of the modules or submodules may or may not be physical modules or submodules, that is, they may be located in one place, or they may be distributed on multiple network modules or submodules. Some or all of the modules or submodules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0079] In addition, each functional module or sub-module in each embodiment of the present application may be integrated into one processing module, or each module or sub-module may exist physically separately, or two or more modules or sub-modules may be integrated into one module.

[0080] Finally, it should be noted that, in this article, 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 an 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 article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the elements.

[0081] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. 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 application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A driving power supply for an energy storage system power supply device, characterized in that: include: A power conversion circuit; wherein: The power conversion circuit is a single-stage power conversion circuit; The input end of the power conversion circuit serves as the input end of the driving power supply; The output end of the power conversion circuit, as the output end of the driving power supply, is connected to the power supply end of the corresponding auxiliary equipment in the energy storage system.

2. The driving power supply of the energy storage system power supply device according to claim 1, characterized in that: The input end of the driving power supply is connected to the DC side of the energy storage converter PCS in the energy storage system.

3. The driving power supply of the energy storage system power supply device according to claim 2, characterized in that: When the energy storage system is started, the input end of the driving power source draws power from the slow-start circuit inside the battery stack in the energy storage system through the DC side of the PCS.

4. The driving power supply of the energy storage system power supply device according to claim 2, characterized in that: When the energy storage system is started, the input end of the driving power supply draws power from the output end of the soft start circuit in the energy storage system; The input end of the soft start circuit is connected to the AC side of the PCS; The output end of the soft-start circuit is connected to the DC side of the PCS.

5. The driving power supply of the energy storage system power supply device according to claim 1, characterized in that: The input end of the driving power supply takes power from the DC side of the AC / DC converter; The AC side of the AC / DC converter receives AC power supply energy outside the energy storage system.

6. The driving power supply of the energy storage system power supply device according to any one of claims 1 to 5, characterized in that: The power supply end of the auxiliary equipment receives alternating current power, and the power conversion circuit is a DC / AC conversion circuit.

7. The driving power supply of the energy storage system power supply device according to any one of claims 1 to 5, characterized in that: The power supply end of the auxiliary device receives direct current power, and the power conversion circuit is a DC / DC conversion circuit.

8. A power supply device for an energy storage system, characterized in that: include: At least one driving power supply of the energy storage system power supply device according to any one of claims 1 to 7; wherein, The output end of the driving power supply is connected to the power supply end of the corresponding auxiliary equipment in the energy storage system; When the number of the driving power supplies is greater than 1, the input ends of the driving power supplies are connected in parallel.

9. The energy storage system power supply device according to claim 8, characterized in that: Also includes: AC / DC converter; The AC side of the AC / DC converter receives AC power supply energy outside the energy storage system; The DC side of the AC / DC converter is connected to the input end of the driving power supply.

10. An energy storage system, characterized in that: include: A battery stack, a PCS, a transformer, at least one auxiliary device and an energy storage system power supply device as claimed in claim 8 or 9; wherein, The battery stack is connected to the DC side of the PCS; The AC side of the PCS is connected to the primary winding of the transformer; The secondary winding of the transformer is used to connect to a power grid and / or a load.

11. The energy storage system according to claim 10, characterized in that: Also includes: Soft start circuit; The input end of the soft start circuit is connected to the AC side of the PCS; The output end of the soft-start circuit is connected to the DC side of the PCS.

12. The energy storage system according to claim 10 or 11, characterized in that: Each of the auxiliary devices includes at least one of the following: A cooling unit for regulating the temperature of the battery stack; Exhaust fans for fire safety; A cooling fan of the PCS; A sub-controller of the PCS.

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