An uninterrupted power supply topology and method based on ac and dc sources

Abstract

The application provides an uninterrupted power supply topology and method based on AC and DC sources, which comprises a lithium ion battery pack, a DC bus, an AC bus, a connector, a charging gun, a first DC / AC inverter, a first on-off component and a second on-off component, the DC bus is connected with the AC bus through the first DC / AC inverter, the AC bus is connected with the connector and an AC load respectively, the lithium ion battery pack is connected with the charging gun and a DC load through the DC bus; the connector is used for connecting with an external AC source, the charging gun is used for connecting with an external DC source, the first on-off component is arranged between the connector and the AC bus, and the second on-off component is arranged between the charging gun and the DC bus. Compared with the prior art, the technical scheme of the application can solve the technical problem that the lithium ion battery pack is prone to thermal runaway when charging and discharging simultaneously in the uninterrupted power supply scene.

Description

Technical Field

[0001] This invention relates to the field of energy storage and power supply technology, and in particular to an uninterruptible power supply topology and power supply method based on AC and DC sources. Background Technology

[0002] With the rapid development of society and the economy, an increasing number of applications require uninterrupted power supply capabilities, such as hospitals and fire fighting facilities. Lithium-ion batteries have significant advantages, including high energy density, high specific energy, high power density, long cycle life, high operating voltage, and low self-discharge rate, and have recently gained increasing popularity. However, lithium-ion batteries are thermodynamically closed systems. Improper use, such as charging and discharging simultaneously, can lead to thermal runaway, potentially causing fires or even explosions. Therefore, in scenarios requiring uninterrupted power supply, a power supply topology needs to be designed to prevent lithium-ion battery packs from charging and discharging simultaneously. This topology should be able to utilize other AC power devices to provide load power while the battery pack is charging, thus cooperating with the lithium battery pack to achieve uninterrupted power supply. However, currently, there is no topology capable of achieving uninterrupted power supply. Summary of the Invention

[0003] To address one of the problems existing in the prior art, this invention provides an uninterruptible power supply topology and power supply method based on AC and DC sources.

[0004] According to one aspect of the present invention, an uninterruptible power supply topology based on AC source and DC source is provided. The topology includes a lithium-ion battery pack, a DC bus, an AC bus, a connector, a charging gun, a first DC / AC inverter, a first switching component, and a second switching component. The DC bus is connected to the AC bus through the first DC / AC inverter. The AC bus is connected to the connector and the AC load respectively. The lithium-ion battery pack is connected to the charging gun and the DC load respectively through the DC bus.

[0005] The connector is used to connect to an external AC source to obtain AC power from the external AC source, and the charging gun is used to connect to an external DC source to obtain DC power from the external DC source. The first switching component is disposed between the connector and the AC bus to connect and disconnect the connector and the AC bus. The second switching component is disposed between the charging gun and the DC bus to connect and disconnect the charging gun and the AC bus.

[0006] Furthermore, the topology also includes a DC / DC converter, which is positioned between the DC bus and the DC load to perform voltage transformation and filtering on the DC output from the DC bus.

[0007] Furthermore, the topology also includes an AC / DC rectifier and a second DC / AC inverter. One end of the AC / DC rectifier is connected to the AC bus, and the other end is connected to one end of the second DC / AC inverter. The other end of the second DC / AC inverter is connected to the AC load. The AC / DC rectifier is used to rectify the AC power output from the AC bus into DC power and perform filtering. The second DC / AC inverter is used to invert the DC power output from the AC / DC rectifier into AC power and perform filtering.

[0008] Furthermore, both the first and second switching components are contactors.

[0009] Furthermore, the external AC source is 380V AC mains power.

[0010] According to another aspect of the present invention, a method for power supply using the aforementioned topology of the present invention is provided, the method comprising:

[0011] When the lithium-ion battery pack is low on power, connect the connector to an external AC power source.

[0012] The first DC / AC inverter tracks the external AC source for phase locking. When the two phases are synchronized, the first switching component is closed to allow the external AC source to supply power to the AC load through the AC bus.

[0013] Connect the charging gun to an external DC source and close the second on / off component to allow the charging gun to charge the lithium-ion battery pack through the DC bus and supply power to the DC load.

[0014] When the lithium-ion battery pack is fully charged, the second switching component is disconnected to allow the lithium-ion battery pack to supply power to the DC load through the DC bus.

[0015] The first DC / AC inverter tracks an external AC source for phase-locking. When the two are in phase synchronization, the first switching component is disconnected so that the lithium-ion battery pack supplies power to the AC load through the first DC / AC inverter and the AC bus.

[0016] Furthermore, the charging gun charges the lithium-ion battery pack via the DC bus, including:

[0017] The charging gun communicates with the lithium-ion battery pack to obtain the voltage of the lithium-ion battery pack in real time.

[0018] The output voltage of the charging gun is adjusted in real time according to the voltage of the lithium-ion battery pack so that the output voltage of the charging gun is higher than the voltage of the lithium-ion battery pack at the current moment.

[0019] Furthermore, the method also includes using a DC / DC converter to perform voltage transformation and filtering on the DC output from the AC bus.

[0020] Furthermore, the method also includes:

[0021] The AC power output from the AC bus is rectified into DC power and then filtered using an AC / DC rectifier.

[0022] The second DC / AC inverter is used to convert the DC power output from the AC / DC rectifier into AC power and then filter it.

[0023] Furthermore, both the first and second switching components are contactors.

[0024] The present invention provides an uninterruptible power supply topology and method based on AC and DC power sources. This topology connects the AC bus and DC bus via a first DC / AC inverter, connects the lithium-ion battery pack to the charging gun via the DC bus, and connects the connector to the AC bus, thus constructing a topology that includes three power sources: an external AC source, an external DC source, and a lithium-ion battery pack. Furthermore, through the switching control of the first and second switching components, seamless switching between the lithium-ion battery pack, the external AC source, and the external DC source can be achieved, realizing uninterrupted power supply to the load side. Simultaneously, it avoids simultaneous charging and discharging of the lithium-ion battery pack, effectively reducing the risk of thermal runaway. Attached Figure Description

[0025] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 An uninterruptible power supply topology based on AC and DC sources is shown according to a specific embodiment of the present invention. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] like Figure 1 As shown, according to one aspect of the present invention, an uninterruptible power supply topology based on AC source and DC source is provided. The topology includes a lithium-ion battery pack, a DC bus, an AC bus, a connector, a charging gun, a first DC / AC inverter, a first switching component, and a second switching component. The DC bus is connected to the AC bus through the first DC / AC inverter. The AC bus is connected to the connector and the AC load respectively. The lithium-ion battery pack is connected to the charging gun and the DC load respectively through the DC bus.

[0031] The connector is used to connect to an external AC source to obtain AC power from the external AC source, and the charging gun is used to connect to an external DC source to obtain DC power from the external DC source. The first switching component is disposed between the connector and the AC bus to connect and disconnect the connector and the AC bus. The second switching component is disposed between the charging gun and the DC bus to connect and disconnect the charging gun and the AC bus.

[0032] In this invention, the DC bus refers to the common bus of the lithium-ion battery pack and the external DC source, while the AC bus refers to the common bus of the first DC / AC inverter and the external AC source. The types of the first and second switching components are determined as needed. As a specific embodiment of this invention, both the first and second switching components are contactors. Automatic triggering can be achieved using auxiliary contacts of the contactors, thereby improving the automatic control level of the entire structure. Furthermore, in this embodiment of the invention, the external AC source is 380V AC mains power, and the external DC source is a ground-based DC charging device.

[0033] This configuration provides an uninterruptible power supply (UPS) topology based on AC and DC sources. This topology connects the AC and DC buses via a first DC / AC inverter, connects the lithium-ion battery pack to the charging gun via the DC bus, and connects the connector to the AC bus. This creates a topology with three power sources: an external AC source, an external DC source, and the lithium-ion battery pack. By controlling the on / off states of the first and second switching components, seamless switching between the lithium-ion battery pack, the external AC source, and the external DC source can be achieved, ensuring uninterrupted power supply to the load side. Simultaneously, it avoids simultaneous charging and discharging of the lithium-ion battery pack, effectively reducing the risk of thermal runaway. Compared to existing technologies, this invention solves the technical problem of thermal runaway in lithium-ion battery packs that are prone to simultaneous charging and discharging in uninterrupted power supply scenarios.

[0034] To ensure that the DC voltage output from the DC bus matches the rated operating voltage of the DC load to be powered and to reduce current ripple, in this embodiment of the invention, the topology is configured to also include a DC / DC converter. The DC / DC converter is positioned between the DC bus and the DC load and is used to perform voltage transformation and filtering on the DC output from the DC bus. The DC / DC converter has functions such as boosting or bucking the DC voltage and filtering electromagnetic interference. This configuration improves the applicability of the topology and allows it to power various DC loads.

[0035] Furthermore, to ensure that the voltage of the AC power output from the AC bus matches the rated operating voltage of the AC load to be powered and to reduce current ripple, in this embodiment of the invention, the topology is configured to include an AC / DC rectifier and a second DC / AC inverter. One end of the AC / DC rectifier is connected to the AC bus, and the other end is connected to one end of the second DC / AC inverter. The other end of the second DC / AC inverter is connected to the AC load. The AC / DC rectifier rectifies the AC power output from the AC bus into DC power and performs filtering. The second DC / AC inverter inverts the DC power output from the AC / DC rectifier into AC power and performs filtering. The DC / AC inverter has functions such as converting DC power into AC power and filtering electromagnetic interference, while the AC / DC inverter has functions such as rectifying AC power into DC power and filtering electromagnetic interference. This configuration improves the applicability of the topology and allows for power supply to various AC loads.

[0036] According to another aspect of the present invention, a method for power supply using the aforementioned topology of the present invention is provided, the method comprising:

[0037] When the lithium-ion battery pack is low on power, connect the connector to an external AC power source.

[0038] The first DC / AC inverter tracks the external AC source for phase locking. When the two phases are synchronized, the first switching component is closed to allow the external AC source to supply power to the AC load through the AC bus.

[0039] Connect the charging gun to an external DC source and close the second on / off component to allow the charging gun to charge the lithium-ion battery pack through the DC bus and supply power to the DC load.

[0040] When the lithium-ion battery pack is fully charged, the second switching component is disconnected to allow the lithium-ion battery pack to supply power to the DC load through the DC bus.

[0041] The first DC / AC inverter tracks an external AC source for phase-locking. When the two are in phase synchronization, the first switching component is disconnected so that the lithium-ion battery pack supplies power to the AC load through the first DC / AC inverter and the AC bus.

[0042] This approach provides a power supply method that utilizes the phase-locked loop (PLL) technology of a DC / AC inverter to achieve seamless switching between AC and DC power. Using this method, when the lithium-ion battery pack is fully charged, it can supply power to both AC and DC loads using only the lithium-ion battery pack. When the lithium-ion battery pack is depleted and needs charging, it seamlessly switches to using external AC and DC sources to supply power to the AC and DC loads respectively, while simultaneously charging the lithium-ion battery pack using the external DC source. This enables uninterrupted power supply to the load side, while avoiding simultaneous charging and discharging of the lithium-ion battery pack, significantly reducing the risk of thermal runaway and improving the safety and reliability of the lithium-ion battery pack.

[0043] Furthermore, to ensure that the external AC power source can charge the lithium-ion battery pack after being connected to the charging gun, and also to ensure that the lithium-ion battery pack no longer supplies power to external sources, in this embodiment of the invention, the charging gun charges the lithium-ion battery pack through the DC bus, including:

[0044] The charging gun communicates with the lithium-ion battery pack to obtain the voltage of the lithium-ion battery pack in real time.

[0045] The output voltage of the charging gun is adjusted in real time according to the voltage of the lithium-ion battery pack so that the output voltage of the charging gun is higher than the voltage of the lithium-ion battery pack at the current moment.

[0046] In other words, the output voltage of the charging gun is always higher than the voltage of the lithium-ion battery pack, thereby effectively cutting off the external power supply of the lithium-ion battery pack. The difference between the two voltages is determined according to the actual situation, usually slightly higher. In addition, in order to avoid damage to the lithium-ion battery pack due to excessive output voltage of the charging gun, the output voltage of the charging gun is a dynamic value that changes according to the voltage trend of the lithium-ion battery pack. Since the voltage of the lithium-ion battery pack will gradually increase from a low voltage during the charging process, the output voltage of the charging gun will also gradually increase from a low voltage, and at any given moment, the output voltage of the charging gun only needs to be slightly higher than the voltage of the lithium-ion battery pack.

[0047] In addition, in order to ensure that the voltage of the DC power output from the DC bus matches the rated operating voltage of the DC load to be powered and to reduce current ripple, in this embodiment of the invention, the method further includes using a DC / DC converter to perform voltage conversion and filtering on the DC power output from the AC bus.

[0048] Furthermore, in order to ensure that the voltage of the AC power output from the AC bus matches the rated operating voltage of the AC load to be powered and to reduce current ripple, in this embodiment of the invention, the method further includes:

[0049] The AC power output from the AC bus is rectified into DC power and then filtered using an AC / DC rectifier.

[0050] The second DC / AC inverter is used to convert the DC power output from the AC / DC rectifier into AC power and then filter it.

[0051] Furthermore, in a specific embodiment of the present invention, both the first and second switching components are contactors. Automatic triggering can be achieved using auxiliary contacts or other methods of the contactors, thereby improving the level of automatic control in the power supply process.

[0052] To better understand the power supply method proposed in this invention, the following is combined with... Figure 1 The process of this method is illustrated with an example, based on... Figure 1 In this embodiment, S1 is the first switching component, and S2 is the second switching component, both of which are contactors. The external AC source is 380V AC mains power, and the external DC source is a ground-based DC charging device. Furthermore, to facilitate control of the on / off relationship between the lithium-ion battery pack, the load, and the charging gun, this embodiment also includes a contactor S5 between the lithium-ion battery pack and the DC bus, a contactor S3 between the first DC / AC inverter and the DC bus, a contactor S4 between the first DC / AC inverter and the AC bus, and a contactor S6 between the DC / DC converter and the DC bus. The overall working principle is that under normal circumstances, the lithium-ion battery pack supplies power to the load. When the lithium-ion battery pack is charging, to avoid simultaneous charging and discharging, a ground-based DC charging device supplies power to the DC load, and ground-based AC mains power supplies power to the AC load. Seamless switching between ground-based AC mains power and the lithium-ion battery pack or ground-based DC charging device is possible. The specific workflow is as follows:

[0053] 1) Under normal circumstances, the downstream load is powered by the lithium-ion battery pack. At this time, the contactors S1 and S2 are open, and S3, S4, S5 and S6 are closed (and remain closed thereafter). The DC power output from the lithium-ion battery pack is used to power DC loads of different voltage levels through the DC / DC converter, and then used to power AC loads of different voltage levels through the first DC / AC inverter, AC / DC rectifier and the second DC / AC inverter.

[0054] 2) When the lithium-ion battery pack is fully discharged and needs to be recharged, it is first connected to the ground mains power. The first DC / AC inverter tracks the mains power and performs phase locking. When the two phases are synchronized, contactor S1 is closed, and the first DC / AC inverter is in an online, no-output state. The mains power is output to the outside and supplies power to AC loads of different voltage levels through the AC / DC rectifier and the second DC / AC inverter. Then, the ground charging gun is connected. The charging gun communicates with the lithium-ion battery pack to obtain the battery pack voltage in real time. Contactor S2 is closed, and the output voltage of the charging gun changes with the voltage of the battery pack and is slightly higher than the voltage of the battery pack. The DC power output by the charging gun charges the lithium-ion battery pack on one hand and supplies power to the DC load on the other hand through the DC / DC converter.

[0055] 3) When the lithium-ion battery pack is fully charged, contactor S2 is disconnected, and the lithium-ion battery pack automatically and seamlessly switches to external output. The DC power output by the lithium-ion battery pack is used to power DC loads of different voltage levels at the downstream end through the DC / DC converter. The first DC / AC inverter tracks the mains power and performs phase locking. When the two phases are synchronized, contactor S1 is disconnected, and the first DC / AC inverter outputs to the external end and supplies AC loads of different voltage levels at the downstream end through the AC / DC rectifier and the second DC / AC inverter.

[0056] Based on the above embodiments, a different power supply approach for different areas is provided. That is, the ground charging pile equipment and ground mains power are used to power the load inside the base station, while the lithium battery pack is used to power the load outside the base station. This ensures that the lithium-ion battery pack has sufficient power when working in the area outside the base station. In addition, the voltage range of the lithium-ion battery pack can be adjusted according to different application scenarios. That is, the uninterruptible power supply topology and the corresponding power supply method can be applied to a variety of scenarios.

[0057] In summary, this invention provides an uninterruptible power supply topology and method based on AC and DC power sources. This topology connects the AC and DC buses via a first DC / AC inverter, connects the lithium-ion battery pack to the charging gun via the DC bus, and connects the connector to the AC bus, thus constructing a topology with three power sources: an external AC source, an external DC source, and the lithium-ion battery pack. Furthermore, through the on / off control of the first and second switching components, seamless switching between the lithium-ion battery pack, the external AC source, and the external DC source can be achieved, realizing uninterrupted power supply to the load side. Simultaneously, it avoids simultaneous charging and discharging of the lithium-ion battery pack, effectively reducing the risk of thermal runaway. Compared with existing technologies, the technical solution of this invention can solve the technical problem of thermal runaway of lithium-ion battery packs during simultaneous charging and discharging in uninterrupted power supply scenarios.

[0058] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0059] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0060] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for uninterruptible power supply based on AC and DC sources, characterized in that, The method utilizes an uninterruptible power supply topology based on AC and DC sources. The topology includes a lithium-ion battery pack, a DC bus, an AC bus, a connector, a charging gun, a first DC / AC inverter, a first switching component, and a second switching component. The DC bus is connected to the AC bus through the first DC / AC inverter. The AC bus is connected to the connector and the AC load, respectively. The lithium-ion battery pack is connected to the charging gun and the DC load, respectively, through the DC bus. The connector is used to connect to an external AC source to obtain AC power from the external AC source, and the charging gun is used to connect to an external DC source to obtain DC power from the external DC source. The first switching component is disposed between the connector and the AC bus to connect and disconnect the connector and the AC bus. The second switching component is disposed between the charging gun and the DC bus to connect and disconnect the charging gun and the AC bus. The method includes: When the lithium-ion battery pack is low on power, connect the connector to an external AC power source. The first DC / AC inverter is used to track the external AC source for phase locking. When the two phases are synchronized, the first switching component is closed to allow the external AC source to supply power to the AC load through the AC bus. Connect the charging gun to an external DC source, close the second on / off component to allow the charging gun to charge the lithium-ion battery pack through the DC bus and supply power to the DC load; When the lithium-ion battery pack is fully charged, the second switching component is disconnected so that the lithium-ion battery pack supplies power to the DC load through the DC bus; The first DC / AC inverter is used to track the external AC source for phase locking. When the two phases are synchronized, the first switching component is disconnected so that the lithium-ion battery pack supplies power to the AC load through the first DC / AC inverter and the AC bus. The charging gun charges the lithium-ion battery pack via a DC bus, including: The charging gun communicates with the lithium-ion battery pack to obtain the voltage of the lithium-ion battery pack in real time. The output voltage of the charging gun is adjusted in real time according to the voltage of the lithium-ion battery pack so that the output voltage of the charging gun is higher than the voltage of the lithium-ion battery pack at the current moment.

2. The method according to claim 1, characterized in that, The topology also includes a DC / DC converter, which is disposed between the DC bus and the DC load and is used to perform voltage transformation and filtering on the DC power output from the DC bus.

3. The method according to claim 2, characterized in that, The topology also includes an AC / DC rectifier and a second DC / AC inverter. One end of the AC / DC rectifier is connected to the AC bus, and the other end is connected to one end of the second DC / AC inverter. The other end of the second DC / AC inverter is connected to the AC load. The AC / DC rectifier is used to rectify the AC power output from the AC bus into DC power and perform filtering. The second DC / AC inverter is used to invert the DC power output from the AC / DC rectifier into AC power and perform filtering.

4. The method according to claim 3, characterized in that, Both the first switching component and the second switching component are contactors.

5. The method according to any one of claims 1 to 4, characterized in that, The external AC source is 380V AC mains power.

6. The method according to claim 5, characterized in that, The method also includes using a DC / DC converter to perform voltage transformation and filtering on the DC power output from the AC bus.

7. The method according to claim 6, characterized in that, The method further includes: The AC power output from the AC bus is rectified into DC power and filtered using an AC / DC rectifier. The DC power output from the AC / DC rectifier is converted into AC power and then filtered using a second DC / AC inverter.

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