Direct current conversion device and energy storage system

Abstract

The utility model provides a direct-current conversion device, which comprises a first direct-current conversion module and a second direct-current conversion module, and further comprises a first switching module, a second switching module, a third switching module, a fourth switching module and a fifth switching module, the second loop is connected with a first-side positive electrode of the first direct-current conversion module and a first-side positive electrode of the second direct-current conversion module, and the third loop is connected with a first-side negative electrode of the second direct-current conversion module and a first-side negative electrode of the first direct-current conversion module; the first switching module further comprises a first switch unit, and the first switch unit is used for controlling on-off of the first loop, the second loop and the third loop. According to the DC conversion device provided by the embodiment of the invention, wide voltage compatibility can be realized while the conversion efficiency is ensured.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, and particularly to a DC conversion device and an energy storage system. Background Art

[0002] A DC converter usually converts one DC voltage into another DC voltage. In many cases, the input and output DC voltage ranges of a DC converter are very wide, which requires the DC converter to have the ability to handle very wide voltage ranges.

[0003] In the field of energy storage applications, batteries are usually connected to the power grid through a DC / DC converter and a PCS (Power Conversion System). The PCS can convert AC and DC power into each other. The power grids connected by the PCS in different application scenarios are different, divided into single-phase power grids and three-phase power grids. When the PCS is connected to a single-phase power grid, the DC voltage output by the conversion of AC power is low, and when it is connected to a three-phase power grid, the DC voltage output by the conversion of AC power is high. Therefore, for these two different application scenarios, a DC / DC converter with a low input voltage and a DC / DC converter with a high input voltage are usually designed separately. If a single DC / DC converter is used to be compatible with low and high input voltages, the input voltage range of this DC / DC converter will become very wide, resulting in a significant reduction in the performance such as the efficiency of the DC / DC converter.

[0004] Similarly, in the application scenario of DC charging piles, the power supply of the charging pile module needs to convert AC power into DC power, and its topological structure is usually a front-stage AC / DC converter plus a rear-stage DC / DC converter. When the front-stage AC / DC converter is connected to a single-phase power grid, the output voltage is low, and when it is connected to a three-phase power grid, the output voltage is high. Therefore, the DC / DC converter also has the same problem as above. Facing the two application scenarios, it is necessary to design two DC / DC converters with different input voltage ranges or design a DC / DC converter with a wide input voltage range but poor performance. Summary of the Invention

[0005] To solve the deficiencies of the prior art, the purpose of this application is to provide a DC conversion device and an energy storage system that can achieve wide voltage compatibility while ensuring the conversion efficiency.

[0006] Based on the above purpose, this application provides a DC conversion device. The DC conversion device includes a first DC conversion module and a second DC conversion module. The DC conversion device further includes:

[0007] The first switching module, the first switching module includes a first switching circuit, the first switching circuit includes a first loop connecting the first-side negative electrode of the first DC conversion module and the first-side positive electrode of the second DC conversion module, and a second loop connecting the first-side positive electrode of the first DC conversion module and the first-side positive electrode of the second DC conversion module, and a third loop connecting the first-side negative electrode of the second DC conversion module and the first-side negative electrode of the first DC conversion module;

[0008] The first switching module further includes a first switch unit, the first switch unit is arranged in the first switching circuit, and the first switch unit is used to control the on-off of the first loop, the second loop and the third loop.

[0009] The DC conversion device provided by the embodiment of the present application can realize the series-parallel switching of the first DC conversion module and the second DC conversion module by controlling the on-off of the first loop, the second loop and the third loop, so as to achieve wide-voltage compatibility while ensuring the conversion efficiency.

[0010] In one embodiment, the first switch unit is a double-pole double-throw switch, and the double-pole double-throw switch includes a first moving contact, a second moving contact, a third moving contact, a fourth moving contact, a first static contact and a second static contact. Among them, the first moving contact, the second moving contact and the first static contact are controlled by the first blade, and the third moving contact, the fourth moving contact and the second static contact are controlled by the second blade;

[0011] The first moving contact is electrically connected to the first-side negative electrode of the second DC conversion module, the first static contact is electrically connected to the first-side negative electrode of the first DC conversion module, the second moving contact is electrically connected to the fourth moving contact, the third moving contact is electrically connected to the first-side positive electrode of the first DC conversion module, and the second static contact is electrically connected to the first-side positive electrode of the second DC conversion module.

[0012] In one embodiment, the first switch unit includes a first single-pole double-throw switch and a second single-pole double-throw switch. The first single-pole double-throw switch includes a first moving contact, a second moving contact and a first static contact. The second single-pole double-throw switch includes a third moving contact, a fourth moving contact and a second static contact;

[0013] The first moving contact is electrically connected to the first-side negative electrode of the second DC conversion module, the first static contact is electrically connected to the first-side negative electrode of the first DC conversion module, the second moving contact is electrically connected to the fourth moving contact, the third moving contact is electrically connected to the first-side positive electrode of the first DC conversion module, and the second static contact is electrically connected to the first-side positive electrode of the second DC conversion module.

[0014] In one embodiment, the first switch unit includes a first double-pole single-throw switch and a second double-pole single-throw switch,

[0015] The first double-pole single-throw switch includes a first contact, a second contact, a third contact, and a fourth contact. The first contact and the third contact are controlled by the same blade, and the second contact and the fourth contact are controlled by the same blade;

[0016] The second double-pole single-throw switch includes a fifth contact, a sixth contact, a seventh contact, and an eighth contact. The fifth contact and the seventh contact are controlled by the same blade, and the sixth contact and the eighth contact are controlled by the same blade;

[0017] The first contact is electrically connected to the negative electrode of the first side of the second DC conversion module. The third contact and the fifth contact are commonly electrically connected to the negative electrode of the first side of the first DC conversion module.

[0018] The second contact is electrically connected to the positive electrode of the first side of the first DC conversion module. The fourth contact and the sixth contact are commonly electrically connected to the positive electrode of the first side of the second DC conversion module. The seventh contact and the eighth contact are electrically connected.

[0019] In one embodiment, the first switch unit includes a single-pole double-throw switch and a single-pole single-throw switch.

[0020] The single-pole double-throw switch includes a first moving contact, a second moving contact, and a first static contact.

[0021] The first moving contact is electrically connected to the positive electrode of the first side of the first DC conversion module. The second moving contact is electrically connected to the negative electrode of the first side of the first DC conversion module. The first static contact is electrically connected to the positive electrode of the first side of the second DC conversion module.

[0022] The first end of the single-pole single-throw switch is electrically connected to the negative electrode of the first side of the first DC conversion module. The second end of the single-pole single-throw switch is electrically connected to the negative electrode of the first side of the second DC conversion module.

[0023] In one embodiment, the first switch unit includes a single-pole double-throw switch and a single-pole single-throw switch.

[0024] The single-pole double-throw switch includes a first moving contact, a second moving contact, and a first static contact.

[0025] The first moving contact is electrically connected to the negative electrode of the first side of the second DC conversion module. The first static contact is electrically connected to the negative electrode of the first side of the first DC conversion module. The second moving contact is electrically connected to the positive electrode of the first side of the second DC conversion module.

[0026] The first end of the single-pole single-throw switch is electrically connected to the positive electrode of the first side of the first DC conversion module. The second end of the single-pole single-throw switch is electrically connected to the positive electrode of the first side of the second DC conversion module.

[0027] [[ID=3,6]]In one embodiment, the first switch unit includes a double-pole single-throw switch and a single-pole single-throw switch.

[0028] The double - pole single - throw switch includes a first contact, a second contact, a third contact, and a fourth contact. The first contact and the third contact are controlled by the same blade, and the second contact and the fourth contact are controlled by the same blade;

[0029] The first contact is electrically connected to the positive electrode on the first side of the first DC conversion module. The third contact is electrically connected to the positive electrode on the first side of the second DC conversion module. The fourth contact is electrically connected to the negative electrode on the first side of the second DC conversion module. The second contact is electrically connected to the negative electrode on the first side of the first DC conversion module;

[0030] The first end of the single - pole single - throw switch is electrically connected to the negative electrode on the first side of the first DC conversion module, and the second end of the single - pole single - throw switch is electrically connected to the positive electrode on the first side of the second DC conversion module.

[0031] In one embodiment, the DC conversion device further includes a second switching module. The second switching module includes a second switching circuit. The second switching circuit includes a fourth loop connecting the negative electrode on the second side of the first DC conversion module and the positive electrode on the second side of the second DC conversion module, a fifth loop connecting the positive electrode on the second side of the first DC conversion module and the positive electrode on the second side of the second DC conversion module, and a sixth loop connecting the negative electrode on the second side of the second DC conversion module and the negative electrode on the second side of the first DC conversion module;

[0032] The second switching module further includes a second switch unit. The second switch unit is disposed in the second switching circuit, and the switch unit is used to control the on - off of the fourth loop, the fifth loop, and the sixth loop.

[0033] In one embodiment, the first switch unit and the second switch unit have the same structure.

[0034] This application also provides an energy storage system. The energy storage system includes a DC power supply device, an inverter, and the DC conversion device as described above. The first side of the DC conversion device is connected to the DC power supply device, and the second side of the DC conversion device is connected to the inverter.

[0035] The energy storage system provided by the embodiment of this application can realize the series - parallel switching of the first DC conversion module and the second DC conversion module by controlling the on - off of the first loop, the second loop, and the third loop, so as to achieve wide - voltage compatibility while ensuring the conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the DC conversion device provided by the first embodiment of this application;

[0037] Figure 2 [[ID=3E1]]It is a schematic diagram of the DC conversion device provided by the second embodiment of this application;

[0038] Figure 3Schematic diagram of the DC conversion device provided by the third embodiment of the present application;

[0039] Figure 4 Schematic diagram of the DC conversion device provided by the fourth embodiment of the present application;

[0040] Figure 5 Schematic diagram of the DC conversion device provided by the fifth embodiment of the present application;

[0041] Figure 6 Schematic diagram of the DC conversion device provided by the sixth embodiment of the present application. Detailed implementation manners

[0042] The following will describe the present application in detail in conjunction with the specific implementation manners shown in the drawings. However, these implementation manners do not limit the present application, and any structural, method, or functional transformation made by those of ordinary skill in the art based on these implementation manners is included in the protection scope of the present application.

[0043] The present application provides a DC conversion device. The DC conversion device includes a first DC conversion module and a second DC conversion module. The DC conversion device further includes:

[0044] A first switching module. The first switching module includes a switching circuit. The switching circuit includes a first loop connecting the negative electrode on the first side of the first DC conversion module and the positive electrode on the first side of the second DC conversion module, a second loop connecting the positive electrode on the first side of the first DC conversion module and the positive electrode on the first side of the second DC conversion module, and a third loop connecting the negative electrode on the first side of the second DC conversion module and the negative electrode on the first side of the first DC conversion module;

[0045] The first switching module further includes at least one switching unit. The switching unit is arranged in the switching circuit, and the switching unit is used to control the on / off of the first loop, the second loop, and the third loop.

[0046] According to the DC conversion device provided by the embodiment of the present application, by controlling the on / off of the first loop, the second loop, and the third loop, the series-parallel switching of the first DC conversion module and the second DC conversion module can be realized, so as to achieve wide voltage compatibility while ensuring the conversion efficiency.

[0047] Specifically, when the second loop and the third loop are both turned on and the first loop is turned off, the first DC conversion module is in parallel with the second DC conversion module. At this time, the voltage on the first side of the first DC conversion module and the second DC conversion module is the same as the voltage of the DC source. This state is applicable to the case of a lower voltage level, that is, the voltage level should be lower than the maximum rated voltage of a single DC conversion module.

[0048] When the first circuit is conducting and the second and third circuits are both open, the first DC conversion module and the second DC conversion module are connected in series. The two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only achieves compatibility with high voltage levels but also prevents each DC conversion module from exceeding its maximum rated voltage, ensuring that each DC conversion module can operate efficiently within the preset voltage range.

[0049] It should be noted that the first side of the first DC conversion module and the second DC conversion module can refer to the input side of the DC conversion module or the output side of the DC conversion module.

[0050] In one embodiment, the DC conversion device further includes a second switching module. The structure of the second switching module can be the same as that of the first switching module, except that the second switching module is arranged on the second side of the first DC conversion module and the second DC conversion module to achieve series-parallel switching of the second sides of the first DC conversion module and the second DC conversion module. It should be understood that this embodiment enables both ends of the DC conversion device to achieve compatibility with a wide voltage level, thereby meeting the requirements of bidirectional current conversion.

[0051] For the convenience of description, the following takes the first side as the input side of the DC conversion module and the second side as the output side of the DC conversion module as an example for description.

[0052] As Figure 1 shown, in the first embodiment, the switch unit is a double-pole double-throw switch K 11 , and the double-pole double-throw switch K 11 includes a first moving contact a 11 , a second moving contact a 12 , a third moving contact a 13 , a fourth moving contact a 14 , a first static contact s 11 and a second static contact s 12 . Among them, the first moving contact a 11 , the second moving contact a 12 and the first static contact s 11 are controlled by the first blade, and the third moving contact a 13 , the fourth moving contact a 14 and the second static contact s 12 are controlled by the second blade.

[0053] The first moving contact a 11 is electrically connected to the negative electrode of the first side of the second DC conversion module, the first static contact s 11 is electrically connected to the negative electrode of the first side of the first DC conversion module 11, the second moving contact a 12 is electrically connected to the fourth moving contact a 14 , and the third moving contact a 13Electrically connected to the positive electrode on the first side of the first DC conversion module, the second static contact s 12 Electrically connected to the positive electrode on the first side of the second DC conversion module 12.

[0054] Refer to Figure 1 , when controlling the first blade to contact the first moving contact a 11 and the second blade to contact the third moving contact a 13 At this time, the first circuit is disconnected, the second and third circuits are conducting, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are in parallel. At this time, the voltage on the first sides of the first DC conversion module 11 and the second DC conversion module 12 is the same as the voltage of the DC source (i.e., V in =V busa1 =V busb1 ), and this state is applicable to the case of a lower voltage level.

[0055] When controlling the first blade to contact the second moving contact a 12 and the second blade to contact the fourth moving contact a 14 At this time, the first circuit is conducting, the second and third circuits are both disconnected, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are in series. At this time, the two DC conversion modules share the voltage of the DC source (i.e., V in =V busa1 +V busb1 ), and at this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels but also avoids each DC conversion module exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0056] As Figure 1 shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here. By controlling the state switching of the switching unit of the second switching module 14, the series-parallel switching of the second sides of the first DC conversion module 11 and the second DC conversion module 12 can be realized, enabling both ends of the DC conversion device to achieve compatibility of wide voltage levels, and further meeting the requirements of bidirectional current conversion. And Figure 1 in the DC conversion device shown, one switching module is realized only by one relay, only one control variable is required, and the circuit structure is simple and the control is convenient.

[0057] As Figure 2 shown, in the second embodiment, the switching unit includes a first single-pole double-throw switch K 21 and a second single-pole double-throw switch K 22 , the first single-pole double-throw switch K 21 includes a first moving contact a 21 , a second moving contact a 22 and a first static contact s 21, the second single-pole double-throw switch K 22 includes a third moving contact a 23 , a fourth moving contact a 24 and a second stationary contact s 22 ;

[0058] The first moving contact a 21 is electrically connected to the negative electrode of the first side of the second DC conversion module, and the first stationary contact s 21 is electrically connected to the negative electrode of the first side of the first DC conversion module 11. The second moving contact a 22 is electrically connected to the fourth moving contact a 24 , and the third moving contact a 23 is electrically connected to the positive electrode of the first side of the first DC conversion module. The second stationary contact s 22 is electrically connected to the positive electrode of the first side of the second DC conversion module 12.

[0059] Referring to Figure 2 , the principle of the second embodiment is similar to that of the first embodiment. When controlling the first single-pole double-throw switch K 21 's blade contacts the first moving contact a 21 , and the second single-pole double-throw switch K 22 's blade contacts the third moving contact a 23 , at this time, the first loop is disconnected, the second loop and the third loop are conducting, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are in parallel. At this time, the voltage on the first sides of the first DC conversion module 11 and the second DC conversion module 12 is the same as the voltage of the DC source. This state is applicable to the case of a lower voltage level.

[0060] When controlling the first single-pole double-throw switch K 21 's blade contacts the second moving contact a 22 , and the second single-pole double-throw switch K 22 's blade contacts the fourth moving contact a 24 , at this time, the first loop is conducting, the second loop and the third loop are both disconnected, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are in series. At this time, the two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels but also avoids each DC conversion module exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0061] As Figure 2 shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here.

[0062] As Figure 3 shown, in the third embodiment, the switch unit includes a first double-pole single-throw switch K 31and the second double-pole single-throw switch K 32 .

[0063] The first double-pole single-throw switch K 31 includes a first contact a 31 , a second contact a 32 , a third contact s 31 and a fourth contact s 32 . The first contact a 31 and the third contact s 31 are controlled by the same blade, and the second contact a 32 and the fourth contact s 32 are controlled by the same blade.

[0064] The second double-pole single-throw switch K 32 includes a fifth contact a 33 , a sixth contact a 34 , a seventh contact s 33 and an eighth contact s 34 . The fifth contact a 33 and the seventh contact s 33 are controlled by the same blade, and the sixth contact a 34 and the eighth contact s 34 are controlled by the same blade.

[0065] The first contact a 31 is electrically connected to the negative electrode on the first side of the second DC conversion module. The third contact s 31 and the fifth contact a 33 are commonly electrically connected to the negative electrode on the first side of the first DC conversion module 11. The second contact a 32 is electrically connected to the positive electrode on the first side of the first DC conversion module. The fourth contact s 32 and the sixth contact a 34 are commonly electrically connected to the positive electrode on the first side of the second DC conversion module 12. The seventh contact s 33 and the eighth contact s 34 are electrically connected.

[0066] Referring to Figure 3 , when the first double-pole single-throw switch K 31 is closed and the second double-pole single-throw switch K 32 is opened, the first contact a 31 is connected to the third contact s 31 , the third loop is conducted, the second contact a 32 is connected to the fourth contact s 32 , the second loop is conducted, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are paralleled. At this time, the voltages on the first sides of the first DC conversion module 11 and the second DC conversion module 12 are the same as the voltage of the DC source, and this state is applicable to the case of a lower voltage level.

[0067] When controlling the first double-pole single-throw switch K 31 is disconnected and the second double-pole single-throw switch K 32 is closed, the negative electrode of the first side of the first DC conversion module 11 is successively connected to the fifth contact a 33 , the seventh contact s 33 , the eighth contact s 34 and the sixth contact a 34 and is finally connected to the positive electrode of the first side of the second DC conversion module 12, realizing the series connection of the first sides of the first DC conversion module 11 and the second DC conversion module 12. At this time, the two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels but also prevents each DC conversion module from exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0068] It should be noted that Figure 3 in 31 , the first contact a 32 , the second contact a 33 , the fifth contact a 34 , the sixth contact a 31 are moving contacts, and the third contact s 32 , the fourth contact s 33 , the seventh contact s 34 are static contacts. In actual applications, the positions of the moving and static contacts of the single-throw switch can be interchanged.

[0069] As Figure 3 shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here.

[0070] Compared with Figure 1 the DC conversion device shown Figure 3 the DC conversion device shown adds a relay in each switching module, also only requires one control variable, and can prevent problems such as switch adhesion, improving safety.

[0071] As Figure 4 shown, in the fourth embodiment, the switch unit includes a single-pole double-throw switch K 41 and a single-pole single-throw switch K 42 . The single-pole double-throw switch K 41 includes a first moving contact a 41 , a second moving contact a 42 and a first static contact s 41 .

[0072] The first moving contact a 41Electrically connected to the positive electrode of the first side of the first DC conversion module, the second moving contact a 42 Electrically connected to the negative electrode of the first side of the first DC conversion module 11, the first static contact s 41 Electrically connected to the positive electrode of the first side of the second DC conversion module 12

[0073] Single-pole single-throw switch K 42 The first end of is electrically connected to the negative electrode of the first side of the first DC conversion module 11, the single-pole single-throw switch K 42 The second end of is electrically connected to the negative electrode of the first side of the second DC conversion module.

[0074] Refer to Figure 4 , when the single-pole double-throw switch K 41 The blade of contacts the first moving contact a 41 And, the single-pole single-throw switch K 42 Is closed. At this time, the first loop is disconnected, and the second and third loops are conducted, realizing the parallel connection of the first sides of the first DC conversion module 11 and the second DC conversion module 12. At this time, the voltages on the first sides of the first DC conversion module 11 and the second DC conversion module 12 are the same as the voltage of the DC source. This state is applicable to the case of a lower voltage level.

[0075] When the single-pole double-throw switch K 41 The blade of contacts the second moving contact a 42 And, the single-pole single-throw switch K 42 Is disconnected. At this time, the first loop is conducted, and the second and third loops are disconnected, realizing the series connection of the first sides of the first DC conversion module 11 and the second DC conversion module 12. At this time, the two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels, but also avoids each DC conversion module exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0076] As<> Figure 4 Shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here.

[0077] As Figure 5 Shown, in the fifth embodiment, the switch unit includes a single-pole double-throw switch K 52 And a single-pole single-throw switch K 51 . The single-pole double-throw switch K 52 Includes the first moving contact a 51 , the second moving contact a 52 And the first static contact s 51 . The first moving contact a 51 Is electrically connected to the negative electrode of the first side of the second DC conversion module, the first static contact s 51It is electrically connected to the negative electrode of the first side of the first DC conversion module 11, and the second moving contact a 52 is electrically connected to the positive electrode of the first side of the second DC conversion module 12; the single-pole single-throw switch K 51 has its first end electrically connected to the positive electrode of the first side of the first DC conversion module, and the single-pole single-throw switch K 51 has its second end electrically connected to the positive electrode of the first side of the second DC conversion module 12.

[0078] Refer to Figure 5 , when the single-pole single-throw switch K 51 is closed, and the blade of the single-pole double-throw switch K 52 contacts the first moving contact a 51 , at this time, the second loop and the third loop are conducted, and the first loop is disconnected, realizing the parallel connection of the first sides of the first DC conversion module 11 and the second DC conversion module 12. In this state, the voltage on the first sides of the first DC conversion module 11 and the second DC conversion module 12 is the same as the voltage of the DC source, which is suitable for the case of a lower voltage level.

[0079] When the single-pole single-throw switch K 51 is disconnected, and the blade of the single-pole double-throw switch K 52 contacts the second moving contact a 52 , at this time, the first loop is conducted, and the second loop and the third loop are disconnected, realizing the series connection of the first sides of the first DC conversion module 11 and the second DC conversion module 12. In this state, the two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels, but also avoids each DC conversion module exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0080] As Figure 5 shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here.

[0081] As Figure 6 shown, in the sixth embodiment, the switch unit includes a double-pole single-throw switch K<D 61 and a single-pole single-throw switch K 62 , the double-pole single-throw switch K 61 includes a first contact a 61 , a second contact a 62 , a third contact s 61 and a fourth contact s 62 , the first contact a 61 and the third contact s 61 are controlled by the same blade, and the second contact a 62 and the fourth contact s 62 are controlled by the same blade.

[0082] The first contact a 61 Electrically connected to the positive electrode of the first side of the first DC conversion module, the third contact s 61 Electrically connected to the positive electrode of the first side of the second DC conversion module 12, the fourth contact s 62 Electrically connected to the negative electrode of the first side of the second DC conversion module, the second contact a 62 Electrically connected to the negative electrode of the first side of the first DC conversion module 11; the single-pole single-throw switch K 62 The first end of is electrically connected to the negative electrode of the first side of the first DC conversion module 11, the single-pole single-throw switch K 62 The second end of is electrically connected to the positive electrode of the first side of the second DC conversion module 12.

[0083] Referring to Figure 6 , when the double-pole single-throw switch K 61 is closed and the single-pole single-throw switch K 62 is open, at this time the first loop is disconnected, the second loop and the third loop are conducted, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are connected in parallel. At this time, the voltages on the first sides of the first DC conversion module 11 and the second DC conversion module 12 are the same as the voltage of the DC source, and this state is applicable to the case of a lower voltage level.

[0084] When the double-pole single-throw switch K 61 is open and the single-pole single-throw switch K 62 is closed, at this time the first loop is conducted, the second loop and the third loop are disconnected, and the first sides of the first DC conversion module 11 and the second DC conversion module 12 are connected in series. At this time, the two DC conversion modules share the voltage of the DC source. At this time, the DC voltage conversion device not only realizes the compatibility of high voltage levels, but also prevents each DC conversion module from exceeding the maximum rated voltage, ensuring that each DC conversion module can work efficiently within the preset voltage range.

[0085] It should be noted that Figure 6 in, the first contact a 61 and the second contact a 61 of the double-pole single-throw switch K 62 are moving contacts, the third contact s 61 and the fourth contact s 62 are static contacts. In actual applications, the positions of the moving and static contacts of the single-throw switch can be interchanged.

[0086] As Figure 6 shown, the structure of the second switching module 14 is the same as that of the first switching module 13, and will not be elaborated here. Compared with Figure 3 the DC conversion device shown, Figure 6The DC conversion device shown replaces one double-pole single-throw relay in the switching module with a single-pole single-throw relay, achieving the same effect of wide voltage level compatibility while reducing costs.

[0087] It should be noted that in another embodiment, the structure of the second switching module 14 may be different from that of the first switching module 13. The first switching module 13 and the second switching module 14 may be a combination of the switching modules of any two of the above embodiments.

[0088] This application also provides an energy storage system, including a DC power supply device, an inverter, and the DC conversion device provided by the embodiments of this application. The first side of the DC conversion device is connected to the DC power supply device, and the second side of the DC conversion device is connected to the inverter.

[0089] According to the above description, for the DC conversion device and the energy storage system provided by the embodiments of this application, by controlling the on / off of the first loop, the second loop, and the third loop, the series-parallel switching of the first DC conversion module 11 and the second DC conversion module 12 can be realized, so as to achieve wide voltage compatibility while ensuring the conversion efficiency.

[0090] Although the preferred embodiments of this application have been disclosed for illustrative purposes, those of ordinary skill in the art will realize that various improvements, additions, and substitutions are possible without departing from the scope and spirit of this application disclosed by the appended claims.

Claims

1. A DC conversion device, the DC conversion device includes a first DC conversion module and a second DC conversion module, characterized in that, The DC conversion device further includes: A first switching module, the first switching module includes a first switching circuit, the first switching circuit includes a first loop connecting the first side negative electrode of the first DC conversion module and the first side positive electrode of the second DC conversion module, and a second loop connecting the first side positive electrode of the first DC conversion module and the first side positive electrode of the second DC conversion module, and a third loop connecting the first side negative electrode of the second DC conversion module and the first side negative electrode of the first DC conversion module; The first switching module further includes a first switch unit, the first switch unit is arranged in the first switching circuit, and the first switch unit is used to control the on / off of the first loop, the second loop and the third loop.

2. The DC conversion device according to claim 1, wherein The first switch unit is a double-pole double-throw switch, the double-pole double-throw switch includes a first moving contact, a second moving contact, a third moving contact, a fourth moving contact, a first static contact and a second static contact. Among them, the first moving contact, the second moving contact and the first static contact are controlled by a first blade, and the third moving contact, the fourth moving contact and the second static contact are controlled by a second blade; The first moving contact is electrically connected to the first side negative electrode of the second DC conversion module, the first static contact is electrically connected to the first side negative electrode of the first DC conversion module, the second moving contact is electrically connected to the fourth moving contact, the third moving contact is electrically connected to the first side positive electrode of the first DC conversion module, and the second static contact is electrically connected to the first side positive electrode of the second DC conversion module.

3. The DC conversion device according to claim 1, wherein The first switch unit includes a first single-pole double-throw switch and a second single-pole double-throw switch. The first single-pole double-throw switch includes a first moving contact, a second moving contact and a first static contact. The second single-pole double-throw switch includes a third moving contact, a fourth moving contact and a second static contact; The first moving contact is electrically connected to the first side negative electrode of the second DC conversion module, the first static contact is electrically connected to the first side negative electrode of the first DC conversion module, the second moving contact is electrically connected to the fourth moving contact, the third moving contact is electrically connected to the first side positive electrode of the first DC conversion module, and the second static contact is electrically connected to the first side positive electrode of the second DC conversion module.

4. The DC conversion device according to claim 1, wherein The first switch unit includes a first double-pole single-throw switch and a second double-pole single-throw switch The first double-pole single-throw switch includes a first contact, a second contact, a third contact and a fourth contact. The first contact and the third contact are controlled by the same blade, and the second contact and the fourth contact are controlled by the same blade; The second double-pole single-throw switch includes a fifth contact, a sixth contact, a seventh contact and an eighth contact. The fifth contact and the seventh contact are controlled by the same blade, and the sixth contact and the eighth contact are controlled by the same blade; The first contact is electrically connected to the first-side negative electrode of the second DC conversion module, and the third contact and the fifth contact are jointly electrically connected to the first-side negative electrode of the first DC conversion module. The second contact is electrically connected to the first-side positive electrode of the first DC conversion module, the fourth contact and the sixth contact are jointly electrically connected to the first-side positive electrode of the second DC conversion module, and the seventh contact and the eighth contact are electrically connected.

5. The DC conversion device according to claim 1, wherein: The first switch unit includes a single-pole double-throw switch and a single-pole single-throw switch. The single-pole double-throw switch includes a first moving contact, a second moving contact, and a first stationary contact. The first moving contact is electrically connected to the first-side positive electrode of the first DC conversion module, the second moving contact is electrically connected to the first-side negative electrode of the first DC conversion module, and the first stationary contact is electrically connected to the first-side positive electrode of the second DC conversion module. The first end of the single-pole single-throw switch is electrically connected to the first-side negative electrode of the first DC conversion module, and the second end of the single-pole single-throw switch is electrically connected to the first-side negative electrode of the second DC conversion module.

6. The DC conversion device according to claim 1, wherein: The first switch unit includes a single-pole double-throw switch and a single-pole single-throw switch. The single-pole double-throw switch includes a first moving contact, a second moving contact, and a first stationary contact. The first moving contact is electrically connected to the first-side negative electrode of the second DC conversion module, the first stationary contact is electrically connected to the first-side negative electrode of the first DC conversion module, and the second moving contact is electrically connected to the first-side positive electrode of the second DC conversion module. The first end of the single-pole single-throw switch is electrically connected to the first-side positive electrode of the first DC conversion module, and the second end of the single-pole single-throw switch is electrically connected to the first-side positive electrode of the second DC conversion module.

7. The DC conversion device according to claim 1, wherein: The first switch unit includes a double-pole single-throw switch and a single-pole single-throw switch. The double-pole single-throw switch includes a first contact, a second contact, a third contact, and a fourth contact. The first contact and the third contact are controlled by the same blade, and the second contact and the fourth contact are controlled by the same blade. The first contact is electrically connected to the first-side positive electrode of the first DC conversion module, the third contact is electrically connected to the first-side positive electrode of the second DC conversion module, the fourth contact is electrically connected to the first-side negative electrode of the second DC conversion module, and the second contact is electrically connected to the first-side negative electrode of the first DC conversion module. The first end of the single-pole single-throw switch is electrically connected to the first-side negative electrode of the first DC conversion module, and the second end of the single-pole single-throw switch is electrically connected to the first-side positive electrode of the second DC conversion module.

8. The DC conversion device according to claim 1, wherein: The DC conversion device further includes a second switching module. The second switching module includes a second switching circuit. The second switching circuit includes a fourth loop connecting the negative electrode of the second side of the first DC conversion module and the positive electrode of the second side of the second DC conversion module, a fifth loop connecting the positive electrode of the second side of the first DC conversion module and the positive electrode of the second side of the second DC conversion module, and a sixth loop connecting the negative electrode of the second side of the second DC conversion module and the negative electrode of the second side of the first DC conversion module; The second switching module further includes a second switch unit. The second switch unit is disposed in the second switching circuit, and the switch unit is used to control the on / off of the fourth loop, the fifth loop, and the sixth loop.

9. The DC conversion device according to claim 8, wherein The first switch unit has the same structure as the second switch unit.

10. A energy storage system, characterized in that, The energy storage system includes a DC power supply device, an inverter, and the DC conversion device according to any one of claims 1 to 9. The first side of the DC conversion device is connected to the DC power supply device, and the second side of the DC conversion device is connected to the inverter.

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