Power management circuit

Abstract

The utility model provides a power management circuit, which is characterized in that when the power management circuit is in a first working state, an alternating current power supply supplies power to a load through the power management circuit, when the power management circuit is in a second working state, a first direct current power supply supplies power to the load through the power management circuit, and the power management circuit comprises a controller which is configured to supply power to the load through the power management circuit when the first working state is switched to the second working state; when the first working state is switched to the first working state, the first relay is disconnected, the second relay is closed, when the second working state is switched to the first working state, the second relay is disconnected, the first relay is closed, and the power management circuit is connected with the alternating-current power supply through the first relay and connected with the first direct-current power supply through the second relay; and the second direct-current power supply is configured to charge the power supply management circuit in a floating manner in any working state, and supplies power to the load through the first voltage conversion module when the first working state is switched to the second working state. According to the circuit, stable power supply for the load is realized in a low-cost mode, and the circuit can be adapted to different types of loads.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power management, and particularly relates to a power management circuit. BACKGROUND

[0002] The power supply mode of the load is mainly divided into two kinds of direct current power supply and alternating current power supply. Direct current power supply usually relies on energy storage devices such as batteries, and is suitable for some devices requiring stable voltage or short-term backup power supply scenarios. However, with the upgrading of market demand and the continuous improvement of the requirement of national standards on the charging and discharging efficiency of the energy storage system on the direct current side, long-term use of direct current power supply is gradually considered as an inefficient and unsustainable way. In addition, the direct current power supply mode may also face problems such as capacity attenuation and limited cycle life in actual application, making it difficult to meet the demand in long-term operation. While alternating current power supply mainly relies on commercial power to supply power to the load, and is widely used in daily life and industrial equipment. However, the reliability of alternating current power supply is easily limited by the stability of power supply, and once a power failure occurs, the normal operation of the load may be immediately interrupted, which brings potential risks to the continuity and safety of the system.

[0003] In order to solve the above problems, uninterruptible power supply (UPS) is generally used as a supplementary solution in the prior art. UPS can quickly switch to battery power supply when the commercial power is cut off by combining battery energy storage and inverter technology, so as to ensure the continuous power supply of the load. However, the UPS device has obvious limitations in actual application. On the one hand, the cost of the UPS device is relatively high, especially in the scene requiring high power output or long time backup power supply, the investment cost will increase significantly; on the other hand, the volume of the UPS device is usually large, which is difficult to meet the specific demand in the application scene with limited space or requiring lightweight design.

[0004] Therefore, how to realize stable power supply for the load in a low-cost way is a technical problem to be solved. CONTENT OF THE INVENTION

[0005] Therefore, the present application discloses a power management circuit for realizing stable power supply for the load in a low-cost way.

[0006] The power management circuit supplies power to the load by the AC power supply in the first working state and supplies power to the load by the first DC power supply in the second working state, and the power management circuit comprises: a controller configured to open the first relay and close the second relay when the first working state is switched to the second working state, and open the second relay and close the first relay when the second working state is switched to the first working state, the power management circuit being connected to the AC power supply through the first relay and connected to the first DC power supply through the second relay; and a second DC power supply configured to float in the power management circuit in any working state and supply power to the load through the first voltage conversion module when the first working state is switched to the second working state.

[0007] Optionally, the AC power supply is a 220V mains power supply, and the first DC power supply is an external battery pack.

[0008] Optionally, the AC power supply and the first DC power supply are converted into 24V voltages through voltage conversion modules in the paths respectively connected to the power management circuit.

[0009] Optionally, the load comprises a first type of load, a second type of load, a third type of load and a fourth type of load; wherein the power supply requirement of the first type of load is 24V, the power supply requirement of the second type of load is 36V, the power supply requirement of the third type of load is 12V, and the power supply requirement of the fourth type of load is 5V.

[0010] Optionally, the power management circuit comprises a second voltage conversion module, a third voltage conversion module and a fourth voltage conversion module; wherein the second voltage conversion module corresponds to the second type of load and is used to output a 36V voltage, the third voltage conversion module corresponds to the third type of load and is used to output a 12V voltage, and the fourth voltage conversion module corresponds to the fourth type of load and is used to output a 5V voltage.

[0011] Optionally, the maximum total power of the first type of load supported by the power management circuit is 450W, the maximum total power of the second type of load and the third type of load supported by the power management circuit is 100W, and the maximum total power of the fourth type of load supported by the power management circuit is 50W.

[0012] Optionally, the controller controls the first relay and the second relay based on the supply voltage of the AC power supply; in the first working state and when the supply voltage of the AC power supply is less than a first preset value, the first relay is opened and the second relay is closed to switch the power management circuit to the second working state; in the second working state and when the supply voltage of the AC power supply is greater than a second preset value and lasts for a first preset time, the second relay is opened and the first relay is closed to switch the power management circuit to the first working state.

[0013] Optionally, the first voltage conversion module is a bidirectional module; when the second DC power supply supplies power to the load, the first voltage conversion module is used to output a 20V voltage; when the voltage of the second DC power supply is less than a third preset value under a static condition, the first voltage conversion module charges the second DC power supply until the voltage of the second DC power supply reaches a fourth preset value and restores the floating state.

[0014] Optionally, the second DC power supply is a battery pack, and the battery in the battery pack is a 27930 battery or a 38121 battery.

[0015] Optionally, the AC power supply and the first DC power supply do not supply power to the power management circuit at the same time.

[0016] In summary, the power management circuit disclosed in the present application has at least the following beneficial effects:

[0017] (1) As a new auxiliary power supply solution for industrial and commercial energy storage systems, the system auxiliary power supply can solve the problem of long-term battery power supply, so as to improve the charge and discharge efficiency of the battery system;

[0018] (2) Compared with the conventional UPS solution, the main functions of the UPS can be achieved, the power supply stability of the energy storage auxiliary power supply system is improved through the switching of the main and standby power supplies, and the automatic switching module solution is more cost-effective and space-saving, which can realize more intelligent and controllable adjustment logic;

[0019] (3) It has the function of multi-voltage platform output, which can meet the diversified demand of the energy storage auxiliary power supply system for voltage platform;

[0020] (4) It has a battery module overvoltage power supply, which can be used as a support power supply for the automatic switching process, so that the auxiliary power supply for the automatic module switching process is more stable. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings used in the description of the embodiments of the present application are briefly introduced as follows:

[0022] Figure 1 is a structural example diagram of a power management circuit provided by the embodiments of the present application.

[0023] Figure 2 is another structural example diagram of a power management circuit provided by the embodiments of the present application.

[0024] In the figure: 100-power management circuit, 110-AC power supply, 120-first DC power supply, 130-load, 101-controller, 102-first relay, 103-second relay, 104-second DC power supply, 105-first voltage conversion module. DETAILED DESCRIPTION

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the specific embodiments of the present application will be described below with reference to the drawings. The drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can be obtained, and adjustments and improvements made without departing from the concept of the present application, all of which fall within the scope of protection of the present application.

[0026] In order to make the drawings simple, only the parts related to the corresponding embodiments are shown in the drawings, which do not represent the actual structure of the product. In addition, in order to make the drawings simple and easy to understand, in some drawings, only some of the parts with the same structure or function are shown, and there can be more or less parts with the same structure or function.

[0027] In the present application, unless otherwise explicitly specified and limited, ordinal numbers such as "first", "second", etc. are only used to distinguish the description of the associated objects, and cannot be understood as indicating or implying the relative importance or order between the associated objects; in addition, it also does not represent the number of associated objects. "Multiple" includes two or more, and other quantifiers are similar. " / " is used to describe the relationship between the associated objects, which represents the "or" relationship between the associated objects. "And / or" is used to describe the relationship between the associated objects, which includes any combination relationship between the associated objects, for example, "a and / or b" includes: "a alone", "b alone", or "a and b". "One or more" or "at least one" of a plurality of objects means any object or any combination of a plurality of objects, for example, "one or more of a1, a2, a3" or "at least one of a1, a2, a3" includes: "a1 alone", "a2 alone", "a3 alone", "a1 and a2", "a1 and a3", "a2 and a3", or "a1, a2 and a3".

[0028] The power supply mode of the load is mainly divided into two kinds of direct current power supply and alternating current power supply. Direct current power supply usually relies on energy storage devices such as batteries, and is suitable for devices requiring stable voltage or short-term backup power supply scenarios. At the same time, as an auxiliary power supply scheme of the system, it has the advantage of stable power supply, which can ensure the continuous work of the key controller of the system when the mains power is cut off, thereby continuously monitoring and protecting the energy storage system. However, direct current power supply directly takes power from the battery side, which will continuously consume battery power during the operation of the energy storage system. The power consumption of most current energy storage system auxiliary power supplies ranges from 100W to 500W (some special systems may exceed 500W), resulting in a daily power loss of about 1-2kWh. With the gradual improvement of market and national standards on the charging and discharging efficiency of the direct current side (battery cluster) of the energy storage system, this auxiliary power supply mode of directly consuming battery power for a long time is gradually considered undesirable. In contrast, alternating current power supply relies on mains power to supply power to the load, although it does not directly consume battery power, but the reliability of the mains power will directly affect the system operation. Once the mains power is cut off, the key controller of the system may stop working due to the loss of power supply, thereby failing to monitor and protect the energy storage system, which brings major safety hazards.

[0029] In the prior art, in order to solve the above problems, an uninterruptible power supply (UPS) is usually used as a supplementary scheme. The UPS can quickly switch to battery power supply when the mains power is cut off by combining battery energy storage and inverter technology, thereby ensuring the continuous power supply of the key controller of the system. However, the UPS scheme also has many limitations. On the one hand, due to the high cost of the UPS device, especially in scenarios requiring long-term backup power supply, the overall cost of the system will increase significantly; on the other hand, the UPS is large in size and occupies internal space of the system, which is not suitable for scenarios requiring compact design. In addition, the battery capacity of the UPS is limited, and when the power-off time is long, the UPS may not be able to completely guarantee the stability of the auxiliary power supply of the system. Whether it is a direct current power supply scheme or an alternating current power supply scheme, the existing auxiliary power supply mode of the system has problems that cannot be ignored. The current power supply source is usually uncontrollable, and in the complex field environment of industrial and commercial energy storage systems, when strong electromagnetic interference occurs, the controller may appear to be down and need to be reset, which further exposes the defects of the existing power supply scheme. In summary, the existing auxiliary power supply scheme of the industrial and commercial energy storage system has obvious shortcomings in power supply stability, efficiency and environmental adaptability, and it is difficult to meet the demand of balancing system reliability and economy. Therefore, an optimized system auxiliary power supply scheme is urgently needed to provide stable, efficient and controllable power support in complex field environments, and to ensure the safety and continuity of the operation of the energy storage system.

[0030] Based on the deficiencies of the prior art above, the core idea of the present application is that, aiming at the actual use scene of the energy storage system, the advantages of direct current power supply and alternating current power supply are comprehensively utilized, an intelligent auxiliary power supply controller is designed, an efficient automatic switching strategy is formulated, and seamless switching of different power supply modes is realized. The controller can replace the traditional UPS function to ensure the stability of auxiliary power supply of the energy storage system in various scenes. Moreover, considering the demand of the auxiliary power system for various voltage platforms, the controller is designed with four different voltage platforms (36V, 24V, 12V and 5V) at the output end, which meets the diversified power supply requirements of the auxiliary power equipment of the energy storage system and improves the compatibility and applicability of the system. In addition, the battery module is configured inside the circuit, and the transformer device outputs a voltage platform slightly lower than 24V, which ensures the continuity and stability of the external auxiliary power supply during power switching. The controller can automatically stop battery power supply after the external power supply is stable, and at the same time, it provides charging function in the battery feeding condition, prolongs the system operation time and improves the overall reliability.

[0031] Figure 1 is a structural example of a power management circuit provided by an embodiment of the present application. Please refer to Figure 1 The present application discloses a power management circuit 100, in the first working state, the alternating current power supply 110 supplies power to the load 130 through the power management circuit 100, in the second working state, the first direct current power supply 120 supplies power to the load 130 through the power management circuit 100, the power management circuit 100 includes: the controller 101 is configured to disconnect the first relay 102 and close the second relay 103 when switching from the first working state to the second working state, and disconnect the second relay 103 and close the first relay 102 when switching from the second working state to the first working state, the power management circuit 100 is connected with the alternating current power supply 110 through the first relay 102 and connected with the first direct current power supply 120 through the second relay 103; the second direct current power supply 104 is configured to float in the power management circuit 100 in any working state, and supply power to the load 130 through the first voltage conversion module 105 when switching from the first working state to the second working state.

[0032] The technical solution disclosed by the application can realize the problem of system auxiliary power supply not using the battery for a long time, so as to improve the charge and discharge efficiency of the battery system; compared with the conventional UPS solution, the power management circuit disclosed by the application can have the main function of the UPS, improve the power supply stability of the energy storage auxiliary power supply system through the switching of the main and backup power supplies, and automatically switch the module solution to save more cost and space and realize more intelligent and controllable adjustment logic; the power management circuit disclosed by the application has the function of multi-voltage platform output, and can meet the diversified demand of the energy storage auxiliary power supply system for the voltage platform; the power management circuit disclosed by the application has the battery module over-power supply, which can be used as the support power supply in the automatic switching process, so that the auxiliary power supply in the automatic module switching process is more stable.

[0033] In the first working state, the external alternating current power supply 110 supplies power to the load 130 through the power management circuit 100; in the second working state, the external first direct current power supply 120 supplies power to the load 130 through the power management circuit 100. In some embodiments of the application, the alternating current power supply 110 and the first direct current power supply 120 do not supply power to the power management circuit 100 at the same time. The above first working state can also be referred to as a normal power supply state, and the alternating current power supply 110 is 220V mains. When the alternating current power supply 110 supplies power continuously and stably, the power management circuit 100 does not perform any processing operation. The above second working state can also be referred to as a mains abnormal state, for example, the mains power supply appears relatively severe fluctuation, or the mains power supply voltage is insufficient. In this case, the power management circuit 100 disconnects the connection between the alternating current power supply 110, and uses the external first direct current power supply 120 to supply power to the load 130, and the first direct current power supply 120 is an external battery pack. For example, the controller 101 in the power management circuit 100 can control the conduction of the alternating current power supply 110 and the first direct current power supply 120 by controlling the relay in the power management circuit 100.

[0034] Please continue to refer to Figure 1 , the power management circuit 100 connects the alternating current power supply 110 through the first relay 102 and connects the first direct current power supply 120 through the second relay 103. When in the first working state, the controller 101 controls the first relay 102 to close and controls the second relay 103 to open, so that the alternating current power supply 110 supplies power to the load 130; when in the second working state, the controller 101 controls the first relay 102 to open and controls the second relay 103 to close, so that the first direct current power supply 120 supplies power to the load 130. The controller 101 can be a microcontroller (MCU) for example.

[0035] In some embodiments of the present application, the AC power supply 110 can also be 380V three-phase AC power, inverter output AC power or variable frequency AC power, etc.; the first DC power supply 120 can also be the output power of a DC generator, the output power of a photovoltaic panel or the output power of a DC regulated power supply, etc. That is, the external AC power supply 110 and the external first DC power supply 120 in the present application are not limited to 220V mains and an external battery pack.

[0036] In some embodiments of the present application, the AC power supply 110 and the first DC power supply 120 are respectively converted to 24V voltage through the voltage conversion modules on the paths of the power management circuit. For the loads on the market, most of them are adapted to 24V voltage; therefore, converting the supply voltage of the AC power supply 110 and the first DC power supply 120 to 24V DC power can directly adapt to most application scenarios. The voltage conversion module between the AC power supply 110 and the power management circuit 100 is an AC-DC conversion module, and the voltage conversion module between the first DC power supply 120 and the power management circuit 100 is a DC-DC conversion module.

[0037] The second DC power supply 104 is arranged on the power management circuit 100, and the second DC power supply 104 can be a battery pack. The batteries in the battery pack are 27930 batteries or 38121 batteries. The size and number of the batteries can be adjusted according to actual application requirements. For example, the battery pack includes two 27930 batteries.

[0038] The second DC power supply 104 is adjusted to an output voltage of about 20V through the first voltage conversion module 105. The voltage output is long-term floating on the power supply loop. When the main power supply (i.e. the AC power supply 110) or the auxiliary power supply (i.e. the first DC power supply 120) supplies power, since their output voltage 24V is higher than the overall output voltage of the battery module, the battery module will not supply power to the outside. However, during the process of switching from the first working state to the second working state, the main power supply or the auxiliary power supply voltage can be lower than 20V. The second DC power supply 104 can support auxiliary power supply for a short time until the switching action is completed, and the main power supply or the auxiliary power supply voltage is stable to return to normal power supply, thereby ensuring the stability of the auxiliary power supply during the power supply switching process. The prior art technical solution mostly ignores the short-term power failure phenomenon that can occur during power conversion. This phenomenon can cause damage to the load when it is serious. The second DC power supply 104 in the present application does not require additional control. Since it is in a floating state, it will not supply power to the load 130 in the first working state or the second working state. Only in the gap (from a few milliseconds to a few seconds) between the first working state and the second working state, it will automatically supply power to the load 130, so that the load 130 does not appear power failure.

[0039] In some embodiments of the present application, the first voltage conversion module 105 is a bidirectional module; when the second DC power supply 104 supplies power to the load 130, the first voltage conversion module 105 is used to output a 20V voltage; when the voltage of the second DC power supply 104 is less than a third preset value under static conditions, the first voltage conversion module 105 charges the second DC power supply 104 until the voltage of the second DC power supply 104 reaches a fourth preset value and resumes the floating state. For example, when the voltage of the second DC power supply 104 is less than 3.15V under static conditions, the first voltage conversion module 105 starts the charging function to charge the second DC power supply 104, and the charging current is 2A; when the charging is stopped at 3.55V, the floating state is resumed.

[0040] In some embodiments of the present application, the controller 101 controls the first relay 102 and the second relay 103 based on the supply voltage of the AC power supply 110; in the first working state and when the supply voltage of the AC power supply 110 is less than a first preset value, the first relay 102 is opened and the second relay 103 is closed, so that the power management circuit 100 is switched to the second working state; in the second working state and when the supply voltage of the AC power supply 110 is greater than a second preset value and lasts for a first preset time, the second relay 103 is opened and the first relay 102 is closed, so that the power management circuit 100 is switched to the first working state. For example, when the controller 101 detects that the supply voltage of the AC power supply 110 is less than 21V (which can be set), the working state of the power management circuit 100 is switched from the first working state to the second working state, the controller 101 controls the second relay 103 to be closed and the first relay 102 to be opened, and before the relay action is completed, the output voltage of the second DC power supply 104 can be used to support the auxiliary power supply, and after the relay action is completed, the load 130 is supplied by the DC side auxiliary power supply (i.e., the first DC power supply 120). In the second working state, when the controller 101 detects that the voltage on the AC side of the AC power supply 110 is restored to 24V (the output voltage of the AC power supply 110 after voltage conversion reaches 24V) and maintains for more than 2 seconds (which can be set), the first relay 102 is closed and the second relay 103 is opened, at which time the system is restored to be supplied by the AC side main power supply, i.e., switched from the second working state to the first working state. The preset time (i.e., 2 seconds in the above example) can ensure the stability of the automatic switching system and prevent false judgment of restoring the main power supply due to the virtual voltage generated by the AC-DC module.

[0041] Figure 2 is another structural example of a power management circuit provided by an embodiment of the present application. Please refer to Figure 2In some embodiments of the present application, the loads include first, second, third and fourth types of loads; wherein the power supply requirements of the first, second, third and fourth types of loads are 24V, 36V, 12V and 5V respectively. Correspondingly, the power management circuit includes second, third and fourth voltage conversion modules; wherein the second voltage conversion module corresponds to the second type of load and is used to output 36V voltage, the third voltage conversion module corresponds to the third type of load and is used to output 12V voltage, and the fourth voltage conversion module corresponds to the fourth type of load and is used to output 5V voltage.

[0042] In some embodiments of the present application, the loads include first, second, third and fourth types of loads; wherein the power supply requirements of the first, second, third and fourth types of loads are 24V, 36V, 12V and 5V respectively. Correspondingly, the power management circuit includes second, third and fourth voltage conversion modules; wherein the second voltage conversion module corresponds to the second type of load and is used to output 36V voltage, the third voltage conversion module corresponds to the third type of load and is used to output 12V voltage, and the fourth voltage conversion module corresponds to the fourth type of load and is used to output 5V voltage. Figure 2 In some embodiments of the present application, the loads include first, second, third and fourth types of loads; wherein the power supply requirements of the first, second, third and fourth types of loads are 24V, 36V, 12V and 5V respectively. Correspondingly, the power management circuit includes second, third and fourth voltage conversion modules; wherein the second voltage conversion module corresponds to the second type of load and is used to output 36V voltage, the third voltage conversion module corresponds to the third type of load and is used to output 12V voltage, and the fourth voltage conversion module corresponds to the fourth type of load and is used to output 5V voltage.

[0043] In some embodiments of the present application, the power management circuit supports a maximum total power of 450W for the first type of load, a maximum total power of 100W for each of the second and third types of loads, and a maximum total power of 50W for the fourth type of load. When multiple voltage output platforms are working simultaneously, the 24V voltage platform output load has priority, and its maximum total power supported is 450W. In addition to the 24V voltage platform output, the 36V and 12V voltage platform outputs support a maximum of 100W, and the 5V voltage platform output supports a maximum of 50W.

[0044] In the above embodiments, the description of each embodiment focuses on different aspects, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments. In addition, the above embodiments can be freely combined as needed.

Claims

1. A power management circuit, characterized by, In the first working state, the AC power supplies power to the load through the power management circuit, and in the second working state, the first DC power supplies power to the load through the power management circuit, and the power management circuit comprises: a controller configured to, when the first working state switches to the second working state, open the first relay and close the second relay, and when the second working state switches to the first working state, open the second relay and close the first relay, the power management circuit being connected to the AC power through the first relay and connected to the first DC power through the second relay; a second DC power configured to float in the power management circuit in any working state and supply power to the load through a first voltage conversion module when the first working state switches to the second working state.

2. The power management circuit of claim 1, wherein, The AC power is 220V mains, and the first DC power is an external battery pack.

3. The power management circuit of claim 2, wherein, The AC power and the first DC power are respectively converted to 24V voltage through voltage conversion modules in the paths to the power management circuit.

4. The power management circuit of claim 1, wherein, The load comprises a first type of load, a second type of load, a third type of load and a fourth type of load; wherein the power supply requirement of the first type of load is 24V, the power supply requirement of the second type of load is 36V, the power supply requirement of the third type of load is 12V, and the power supply requirement of the fourth type of load is 5V.

5. The power management circuit of claim 4, wherein, comprising a second voltage conversion module, a third voltage conversion module and a fourth voltage conversion module; wherein the second voltage conversion module corresponds to the second type of load and is used to output 36V voltage, the third voltage conversion module corresponds to the third type of load and is used to output 12V voltage, and the fourth voltage conversion module corresponds to the fourth type of load and is used to output 5V voltage.

6. The power management circuit of claim 4 or 5, wherein, The maximum total power of the first type of load supported by the power management circuit is 450W, the maximum total power of the second type of load and the third type of load supported by the power management circuit is 100W, and the maximum total power of the fourth type of load supported by the power management circuit is 50W.

7. The power management circuit of claim 1, wherein, The controller controls the first relay and the second relay based on the supply voltage of the AC power; in the first working state and when the supply voltage of the AC power is less than a first preset value, the first relay is opened and the second relay is closed to make the power management circuit switch to the second working state; in the second working state and when the supply voltage of the AC power is greater than a second preset value and lasts for a first preset time, the second relay is opened and the first relay is closed to make the power management circuit switch to the first working state.

8. The power management circuit of claim 1, wherein, The first voltage conversion module is a bidirectional module; when the second DC power supplies power to the load, the first voltage conversion module is used to output 20V voltage; when the voltage of the second DC power is less than a third preset value in a static condition, the first voltage conversion module charges the second DC power until the voltage of the second DC power reaches a fourth preset value and restores the floating state.

9. The power management circuit of claim 1 or 8, wherein, The second direct current power supply is a battery pack, and the battery in the battery pack is a 27930 battery or a 38121 battery.

10. The power management circuit of claim 1, wherein, The alternating current power supply and the first direct current power supply do not supply power to the power management circuit at the same time.

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