Uninterruptible power supply suitable for power grid operation monitoring system

Abstract

The invention relates to the technical field of uninterruptible power supplies, and provides an uninterruptible power supply suitable for a power grid operation monitoring system, which comprises a battery pack, an inverter circuit, a voltage balancing module, an alternating current load interface and a battery management chip, and is characterized in that the battery pack is connected with the alternating current load interface through the inverter circuit; the battery pack comprises a plurality of single batteries, the voltage equalization module comprises a plurality of voltage equalization circuits and a plurality of battery detection circuits, each battery detection circuit is connected with each single battery, and the output end of each battery detection circuit is connected with the battery management chip; every two adjacent single batteries are connected through a voltage balancing circuit, and the battery management chip is connected with each voltage balancing circuit so as to control the current of one single battery in every two adjacent single batteries to flow to the other single battery; voltage balance of the battery pack can be realized, and the safety of the whole battery pack and the reliability of power supply to an important load are ensured.

Description

Technical Field

[0001] This invention relates to the field of uninterruptible power supply technology, and more specifically, to an uninterruptible power supply suitable for power grid operation monitoring systems. Background Technology

[0002] UPS, or Uninterruptible Power Supply, is a type of uninterruptible power supply containing an energy storage device. It is mainly used to provide uninterrupted power to some equipment with high requirements for power stability, such as industrial control computers used in power grid operation monitoring systems. When the mains power is interrupted (power outage), the UPS immediately switches the DC power from the battery to the load through an inverter circuit to continue supplying 220V AC power, so that the load can maintain normal operation and protect the load's software and hardware from damage.

[0003] The uninterruptible power supply (UPS) mainly includes a casing, a battery pack housed within the casing, a charging circuit, an inverter circuit, and an AC load interface. The input and output terminals of the inverter circuit are connected to the battery pack and the AC load interface, respectively, to convert the DC power output from the battery pack into AC power and transmit it to the AC load interface. The input terminal of the charging circuit is connected to the mains power to charge the battery pack. The battery pack consists of multiple battery cells connected in series. However, if the voltage of one battery cell exceeds a preset value during charging while the other battery cells are still charging normally, the battery cell exceeding the preset value may bulge or overcharge, which will affect the safety of the entire battery pack and, consequently, the reliability of power supply to critical loads. Summary of the Invention

[0004] The problem solved by this invention is how to provide overvoltage protection for each individual battery cell in an uninterruptible power supply in order to protect the entire battery pack.

[0005] To address the aforementioned problems, this invention provides an uninterruptible power supply (UPS) suitable for power grid operation monitoring systems, comprising a battery pack, an inverter circuit, a voltage balancing module, an AC load interface, and a battery management chip. The battery pack is connected to the AC load interface via the inverter circuit. The battery pack includes multiple battery cells. The voltage balancing module includes multiple voltage balancing circuits and multiple battery detection circuits. The acquisition terminal of each battery detection circuit is connected to each battery cell to acquire the charging voltage value of the corresponding battery cell. The output terminal of each battery detection circuit is connected to the battery management chip. Adjacent battery cells are connected via the voltage balancing circuits. The battery management chip is connected to the control terminal of each voltage balancing circuit to control the current flow from one battery cell whose charging voltage value exceeds a preset value to the other battery cell.

[0006] Optionally, the voltage equalization circuit includes a buck equalization device and a switching transistor. One end of the buck equalization device is connected to one of the two adjacent battery cells. The source and drain of the switching transistor are respectively connected to the other battery cell and the other end of the buck equalization device. The battery management chip is electrically connected to the gate of the switching transistor.

[0007] Optionally, the buck equalization device includes multiple buck resistors connected in parallel.

[0008] Optionally, the voltage equalization circuit further includes a voltage regulator, which is electrically connected to the switching transistor and the battery management chip respectively.

[0009] Optionally, the inverter circuit includes a first filter circuit and an inverter boost circuit. The battery pack is connected to the input terminal of the inverter boost circuit via the first filter circuit, and the output terminal of the inverter boost circuit is connected to the AC load interface.

[0010] Optionally, the inverter boost circuit includes an inverter switch circuit, a driver chip, and a boost transformer. The input terminal of the inverter switch circuit is connected to the first filter circuit, the driver chip is connected to the control terminal of the inverter switch circuit, the output terminal of the inverter switch circuit is connected to the input terminal of the boost transformer, and the output terminal of the boost transformer is connected to the AC load interface.

[0011] Optionally, the inverter boost circuit further includes a discharge current detection circuit and an amplification circuit. The detection terminal of the discharge current detection circuit is connected to the output terminal of the boost transformer, and the output terminal of the discharge current detection circuit is connected to the driver chip via the amplification circuit.

[0012] Optionally, it also includes a charging circuit, the input terminal of which is adapted to be connected to AC power, the output terminal of which is connected to the output terminal of the step-up transformer, and the driving chip is connected to the control terminal of the charging circuit.

[0013] Optionally, it further includes a DC output circuit, which includes an isolation transformer, a DC control chip, a DC switching circuit, and a DC load interface. The input terminal of the isolation transformer is connected to the output terminal of the first filter circuit, and the output terminal of the isolation transformer is connected to the DC load interface via the DC switching circuit. The DC control chip is connected to the DC switching circuit to control the on / off state of the DC switching circuit.

[0014] Optionally, the DC output circuit further includes an overcurrent protection device, a buck switching circuit, a DC buck chip, a buck controller, a second filter circuit, and a fast charging interface. The input terminal of the overcurrent protection device is connected to the output terminal of the first filter circuit. The output terminal of the overcurrent protection device is connected to the input terminal of the DC buck chip via the buck switching circuit. The output terminal of the DC buck chip is connected to the fast charging interface via the second filter circuit. The buck controller is electrically connected to both the buck switching circuit and the DC buck chip.

[0015] Compared with existing technologies, this invention, when supplying power to important AC loads in the power grid, can convert the DC power output from the battery pack into AC power through an inverter circuit, thereby supplying power to the battery pack through the AC load interface. Each battery cell is equipped with a battery detection circuit to collect the charging voltage value of each battery cell and transmit the detected charging voltage values ​​to the battery management chip in real time. A voltage equalization circuit is connected between adjacent battery cells. When the battery management chip compares the charging voltage value with a preset value, it detects and determines which battery cell's charging voltage value is higher. When the preset value is reached, the voltage equalization circuit corresponding to the battery cell whose charging voltage exceeds the preset value can be closed. This allows the battery cell with a charging voltage higher than the preset value to not only discharge and consume the voltage equalization circuit, but also to have its current flow to another adjacent battery cell. This effectively reduces the voltage of the battery cell with the higher charging voltage, so that the voltage of all battery cells in the battery pack is lower than the preset value. This prevents abnormalities such as bulging or overcharging of battery cells due to voltage exceeding the preset value, thereby achieving voltage equalization of the battery pack, ensuring the safety of the entire battery pack, and further ensuring the reliability of power supply to important loads. Attached Figure Description

[0016] Figure 1 This is one of the principle block diagrams of an uninterruptible power supply applicable to a power grid operation monitoring system in this embodiment of the invention; Figure 2 This is the second principle block diagram of an uninterruptible power supply applicable to a power grid operation monitoring system in this embodiment of the invention; Figure 3 This is a partial structural diagram of an uninterruptible power supply applicable to a power grid operation monitoring system in an embodiment of the present invention; Figure 4 This is a schematic diagram of the voltage equalization circuit and battery management chip in an embodiment of the present invention; Figure 5 This is a schematic diagram of the driver chip structure in an embodiment of the present invention; Figure 6 This is a schematic diagram of the amplifier circuit in an embodiment of the present invention; Figure 7 This is one of the partial structural schematic diagrams of the DC output circuit in an embodiment of the present invention; Figure 8 This is a second partial structural schematic diagram of the DC output circuit in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1-Battery management chip; 2-Battery pack; 21-Battery cell; 3-Inverter circuit; 31-First filter circuit; 32-Inverter boost circuit; 321-Inverter switch circuit; 322-Driver chip; 323-Boost transformer; 324-Discharge current detection circuit; 325-Amplifier circuit; 4-Battery detection circuit; 5-Voltage equalization circuit; 51-Buck equalization device; 52-Switching transistor; 53-Voltage regulator; 6-AC load interface; 7-Charging circuit; 8-DC output circuit; 80-Fast charging interface; 81-Isolation transformer; 82-DC control chip; 83-DC switch circuit; 84-DC load interface; 85-Overcurrent protection device; 86-Buck switch circuit; 87-DC buck chip; 88-Buck controller; 89-Second filter circuit. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0022] To solve the above technical problems, combined with Figure 1 and Figure 2 As shown, this embodiment of the invention provides an uninterruptible power supply suitable for a power grid operation monitoring system. A battery pack 2 is connected to the AC load interface 6 via the inverter circuit 3. The battery pack 2 includes multiple battery cells 21. The voltage balancing module includes multiple voltage balancing circuits 5 and multiple battery detection circuits 4. The acquisition terminal of each battery detection circuit 4 is connected to each battery cell 21 to acquire the charging voltage value of the corresponding battery cell 21. The output terminal of each battery detection circuit 4 is connected to the battery management chip 1. Adjacent battery cells 21 are connected via the voltage balancing circuits 5. The battery management chip 1 is connected to the control terminal of each voltage balancing circuit 5 to control the current flow from one battery cell 21 whose charging voltage value exceeds a preset value to the other battery cell 21.

[0023] It should be noted that battery pack 2 includes multiple battery cells 21 connected in series to achieve a DC voltage of 220V for the entire battery pack 2. This provides power to the industrial control computer used to monitor the power grid, ensuring its continuous and reliable operation. Inverter circuit 3 converts the 220V DC output from battery pack 2 into AC power and transmits it to AC load interface 6 to power the AC load. The number of battery detection circuits 4 matches the number of battery cells 21. If there are N battery cells 21, there are also N battery detection circuits 4 and N-1 voltage equalization circuits 5. Battery detection circuits 4 can be voltage detection devices used to monitor the charging voltage of the corresponding battery cells 21 in real time. Battery management chip 1 controls the on / off state of voltage equalization circuits 5 to control whether they consume the energy of battery cells 21 with excessively high charging voltages, effectively reducing the voltage of these cells and ensuring voltage balance across the battery cells 21 on both sides of voltage equalization circuit 5.

[0024] In this embodiment, when supplying power to an important AC load, the DC power output from the battery pack 2 can be converted into AC power by the inverter circuit 3, thereby supplying power to the battery pack 2 through the AC load interface 6. A battery detection circuit 4 is configured for each battery cell 21 to collect the charging voltage value of each battery cell 21 and transmit the detected charging voltage values ​​of each battery cell 21 to the battery management chip 1 in real time. A voltage equalization circuit is connected between two adjacent battery cells 21. When the battery management chip 1 compares the charging voltage value with a preset value to detect and determine which battery cell 21 has a higher charging voltage value than the preset value, a voltage equalization circuit is established. The voltage balancing circuit 5 corresponding to the battery cell 21 whose charging voltage exceeds the preset value can be closed. This allows the battery cell 21 with a charging voltage higher than the preset value to not only discharge and consume the voltage balancing circuit 5, but also to have its current flow to another adjacent battery cell 21. This effectively reduces the voltage of the battery cell 21 with the higher charging voltage, so that the voltage of all battery cells 21 in the battery pack 2 is lower than the preset value. This prevents the battery cells 21 from bulging, overcharging, or other abnormalities due to their voltage exceeding the preset value, thereby achieving voltage balancing in the battery pack 2, ensuring the safety of the entire battery pack 2, and further ensuring the reliability of power supply to important loads.

[0025] In one embodiment of the present invention, combined with Figure 4 As shown, the voltage equalization circuit 5 includes a buck equalization device 51 and a switching transistor 52. One end of the buck equalization device 51 is connected to one of the two adjacent battery cells 21. The source and drain of the switching transistor 52 are respectively connected to the other battery cell 21 and the other end of the buck equalization device 51. The battery management chip 1 is electrically connected to the gate of the switching transistor 52.

[0026] It should be noted that due to the size of the drawings, in cases where... Figure 4 The diagram only shows the series connection structure of six battery cells 21 and the pinout of the battery management chip 1. The first battery cell 21 is named Cell0, the second Cell 21 is named Cell1, and so on, up to the sixth cell 21 named Cell5. A voltage equalization circuit 5 connects adjacent battery cells 21. Figure 4 Taking the first battery cell 21Cell0 and the second battery cell 21Cell1 on the left as an example, the voltage equalization circuit 5 between them includes a buck equalization device 51 and a switching transistor 52. Figure 4The diagram on the right shows the battery management chip 1. For example, if the charging voltage of the second battery cell 21 is detected to be higher than a preset value, where the preset value refers to the maximum charging voltage that a single battery cell 21 is allowed to reach, if the maximum charging voltage is exceeded, the battery cell 21 will experience bulging, fire, explosion, or other faults. At this time, the battery management chip 1 outputs a high level to the gate of the switching transistor 52 to control the switching transistor Q41 to conduct, so that the voltage or current of the second battery cell 21 first flows through the buck equalization device 51 for consumption, thereby reducing the voltage of the second battery cell 21. The voltage or current of the second battery cell 21 will then flow into the first battery cell 21 through the buck equalization device 51 and the switching transistor 52. After the voltages of the two battery cells 21 are balanced, there is no more voltage or current flow, thus balancing the voltages of the two battery cells 21 and effectively protecting the battery cells 21.

[0027] In one embodiment of the present invention, combined with Figure 4 As shown, the step-down equalization device 51 includes multiple step-down resistors connected in parallel.

[0028] It should be noted that by configuring the voltage equalization device 51 as multiple voltage-dropping resistors connected in parallel, the discharge current and amplification speed of battery cells 21 with charging voltage values ​​higher than the preset value can be effectively increased. This allows the voltage of battery cells 21 with charging voltage values ​​higher than the preset value to decrease rapidly to achieve an equalization state, thereby effectively protecting the battery pack 2. Combined with... Figure 4 As shown, each step-down equalization device 51 has two step-down resistors. For example, the two step-down resistors between the first battery cell 21 and the second battery cell 21 are resistor R186 and resistor R187, respectively.

[0029] In one embodiment of the present invention, combined with Figure 4 As shown, the voltage equalization circuit 5 also includes a voltage regulator 53, which is electrically connected to the switching transistor 52 and the battery management chip 1.

[0030] It should be noted that, under normal circumstances, when a single battery cell 21 supplies power to a DC load or when the charging circuit 7 supplies power to multiple battery cells 21 in the battery pack 2, there will be significant voltage fluctuations and harmonics. This not only affects the power supply effect to the DC load or the charging effect to the battery cells 21, but also affects the battery management chip 1 used to control the switching transistor 52. Therefore, by connecting the voltage regulator 53 to the switching transistor 52 and the battery management chip 1 respectively, the discharge voltage or charging voltage of the battery cells 21 can be effectively stabilized, and harmonics can be effectively filtered out, thereby ensuring the normal operation of the battery cells 21 and the battery management system. The voltage regulator 53 includes multiple filter resistors and Zener diodes, such as... Figure 4 In the voltage equalization circuit 5 between the first and second battery cells 21, the voltage regulator 53 includes filter resistor R202, filter resistor R196, and Zener diode D56. Their specific connections are shown in [the diagram / document / reference needed]. Figure 4 This will not be elaborated upon here.

[0031] In one embodiment of the present invention, combined with Figure 2 and Figure 3 As shown, the inverter circuit 3 includes a first filter circuit 31 and an inverter boost circuit 32. The battery pack 2 is connected to the input terminal of the inverter boost circuit 32 via the first filter circuit 31, and the output terminal of the inverter boost circuit 32 is connected to the AC load interface 6.

[0032] It should be noted that battery pack 2 is used to output low-voltage DC power, such as 48V. Then, it passes through the first filter circuit 31, which filters the low-voltage DC power output by battery pack 2 to effectively remove harmonic interference. Subsequently, the inverter boost circuit 32 first inverts the low-voltage DC power and then boosts it to output AC 220V, which is then transmitted to the AC load interface 6 to power important AC loads, such as industrial control computers used in power grid operation monitoring systems.

[0033] The first filter circuit 31 includes filter capacitors C197 to C201, C203, C204, C206, C208 to C211, and C214 to C217 connected in parallel.

[0034] In one embodiment of the present invention, combined with Figure 3 and Figure 5 As shown, the inverter boost circuit 32 includes an inverter switch circuit 321, a driver chip 322, and a boost transformer 323. The input terminal of the inverter switch circuit 321 is connected to the first filter circuit 31, the driver chip 322 is connected to the control terminal of the inverter switch circuit 321, the output terminal of the inverter switch circuit 321 is connected to the input terminal of the boost transformer 323, and the output terminal of the boost transformer 323 is connected to the AC load interface 6.

[0035] It should be noted that the step-up transformer 323 can be represented by T6; the inverter switch circuit 321 includes MOSFETs Q69, Q70, Q71, and Q72. The drain of MOSFET Q69 and the source of MOSFET Q70 are shorted together, and the drain of MOSFET Q71 and the source of MOSFET Q72 are shorted together, and these are connected to the input terminal of the step-up transformer 323. The sources of MOSFETs Q69 and Q71 are shorted together, and the drains of MOSFETs Q70 and Q72 are shorted together, and these are connected to the first filter circuit 31. The driver chip 322 includes... The driver chip 322 includes gate driver U30 and gate driver U31. Pins 3 and 8 of gate driver U31 are electrically connected to the gates of MOSFETs Q70 and Q69, respectively. Pins 3 and 8 of gate driver U30 are electrically connected to the gates of MOSFETs Q72 and Q71, respectively. In other words, by cooperating with gate driver U30 and gate driver U31 in the driver chip 322, the conduction time of the corresponding MOSFET switches can be controlled, which can enable the step-up transformer 323 to output AC power of different levels, so that different levels of AC power can supply AC loads of different voltages.

[0036] In one embodiment of the present invention, combined with Figure 3 As shown, the inverter boost circuit 32 further includes a discharge current detection circuit 324 and an amplifier circuit 325. The detection terminal of the discharge current detection circuit 324 is connected to the output terminal of the boost transformer 323, and the output terminal of the discharge current detection circuit 324 is connected to the driver chip 322 via the amplifier circuit 325.

[0037] It should be noted that by connecting the detection terminal of the discharge current detection circuit 324 to the output terminal of the step-up transformer 323, the output current of the step-up transformer 323 can be monitored in real time. The output current of the step-up transformer 323 can be understood as the discharge current of the battery pack 2 to the AC load. The output terminal of the discharge current detection circuit 324 is connected to the driver chip 322 through the amplifier circuit 325. The amplifier circuit 325 amplifies the discharge current value of the battery pack 2, thereby enabling the driver chip 322 to receive a more stable discharge current value, thus improving the accuracy and reliability of the discharge current value received by the driver chip 322.

[0038] The discharge current detection circuit 324 includes a voltage transformer T7 and a rectifier bridge D95. The voltage transformer T7 is connected to the output terminal of the step-up transformer 323, converting the high-voltage AC output from the step-up transformer 323 into low-voltage AC. This low-voltage AC is then rectified by the rectifier bridge D95 to output a DC current, which is the discharge current. This DC current is then transmitted to the amplifier circuit 325 for amplification. Figure 6 As shown, the amplifier circuit includes operational amplifier U34, resistors R325, R326, R327, R324, capacitors C246 and C245. Their specific connections are shown in [the diagram / reference needed]. Figure 6 The DC current output by the rectifier bridge D95 first flows through resistor R326, and then is amplified by operational amplifier U34. The amplified discharge current then enters the driver chip 322 to realize the data acquisition of the discharge current.

[0039] In one embodiment of the present invention, the uninterruptible power supply suitable for the power grid operation monitoring system further includes a charging circuit 7. The input terminal of the charging circuit 7 is adapted to be connected to the mains power, the output terminal of the charging circuit 7 is connected to the output terminal of the step-up transformer 323, and the driving chip 322 is connected to the control terminal of the charging circuit 7.

[0040] It should be noted that the input and output terminals of the charging circuit 7 are connected to the mains power and the output terminal of the step-up transformer 323, respectively. This allows the AC power output from the mains power to be regulated and controlled, and then stepped down to low-voltage AC power by the step-up transformer 323. The AC power then passes through the inverter switch circuit 321 and the first filter circuit 31 to charge the battery pack 2. The driver chip 322 is a charge / discharge driver chip, which can control the battery pack 2 to discharge power to the AC load through the inverter circuit 3, and can also control the charging circuit 7 to charge the battery pack 2 through the step-up transformer 323, inverter switch circuit 321, and first filter circuit 31. The charging circuit 7 includes MOSFETs Q73, Q74, Q76, and Q77, and the control terminals of the driver chip 322 are connected to MOSFETs Q73, Q74, Q76, and Q77 to control them and output the set AC power. Among them, the control terminals of charging circuit 7 refer to MOSFETs Q73, Q74, Q76, and Q77.

[0041] In one embodiment of the present invention, combined with Figure 2 , Figure 3 and Figure 7As shown, the uninterruptible power supply suitable for the power grid operation monitoring system also includes a DC output circuit 8. The DC output circuit 8 includes an isolation transformer 81, a DC control chip 82, a DC switching circuit 83, and a DC load interface 84. The input terminal of the isolation transformer 81 is connected to the output terminal of the first filter circuit 31. The output terminal of the isolation transformer 81 is connected to the DC load interface 84 via the DC switching circuit 83. The DC control chip 82 is connected to the DC switching circuit 83 to control the on / off state of the DC switching circuit 83.

[0042] It should be noted that the input terminal of the isolation transformer 81 is connected to the output terminal of the first filter circuit 31, thereby electrically isolating the first filter circuit 31 from the subsequent circuit of the isolation transformer 81, effectively preventing mutual interference between the two. The output terminal of the isolation transformer 81 is connected to the DC load interface 84 via the DC switching circuit 83. The DC control chip 82 is connected to the DC switching circuit 83, so the DC control chip 82 can control the conduction time of the DC switching circuit 83 to control the magnitude of the DC voltage supplied by the isolation transformer 81 to the DC load interface 84. Since the DC load is connected to the DC load interface 84, power can be supplied to the DC load. The DC load can be an indicator light or an instrument light, which is not specifically limited here.

[0043] The isolation transformer 81 can be represented by T5, the DC control chip 82 by U32, and the DC switching circuit 83 by MOSFET Q75.

[0044] In one embodiment of the present invention, combined with Figure 2 and Figure 8 As shown, the DC output circuit 8 further includes an overcurrent protection device 85, a step-down switching circuit 86, a DC step-down chip 87, a step-down controller 88, a second filter circuit 89, and a fast charging interface 80. The input terminal of the overcurrent protection device 85 is connected to the output terminal of the first filter circuit 31. The output terminal of the overcurrent protection device 85 is connected to the input terminal of the DC step-down chip 87 via the step-down switching circuit 86. The output terminal of the DC step-down chip 87 is connected to the fast charging interface 80 via the second filter circuit 89. The step-down controller 88 is electrically connected to the step-down switching circuit 86 and the DC step-down chip 87 respectively.

[0045] It should be noted that at present, there are more and more portable smart devices that require fast charging, such as smartphones and tablets. Therefore, in the power grid area, it is usually necessary to fast charge the portable smart devices of the staff. However, when the AC power in the power grid area is interrupted, it is impossible to charge the aforementioned portable smart devices. Therefore, the input terminal of the overcurrent protection device 85 is connected to the output terminal of the first filter circuit 31. At this time, the DC power output by the first filter circuit 31 can first pass through the overcurrent protection device 85 for overcurrent protection, and then the DC power passes through the step-down switch circuit 86 and enters the DC step-down chip 87. At this time, the step-down switch circuit 86 only acts as a switch. Then, the DC power is reduced to another level of low-voltage DC power, such as 5V or 9V, by the DC step-down chip 87. Then, the other level of low-voltage DC power is filtered by the second filter circuit 89 and enters the fast charging interface 80, thereby providing the fast charging interface 80 with a stable low-voltage DC power. Since the fast charging interface can be connected to portable smart terminals such as smartphones and tablets, the portable smart terminals can still be charged in an emergency through the DC output circuit 8 after the AC power in the power grid area is cut off, so as to ensure that the staff can communicate with people outside the power grid area in a timely manner. When the voltage of battery pack 2 is low, in order to save the power consumption of battery pack 2, the buck switch circuit 86 can be disconnected by the buck controller 88, thereby effectively saving the power of battery pack 2; when the voltage of battery pack 2 is high, the buck switch circuit 86 can be turned on by the buck controller 88, thereby making full use of the power of battery pack 2.

[0046] Among them, the overcurrent protection device 85 can be a fuse F2, the step-down switching circuit 86 includes MOSFETs Q58 and Q59, the DC step-down chip 87 is represented by U28, and the second filter circuit 89 is used to filter the low-voltage DC output of the DC step-down chip 87. Its specific structure is shown in [details omitted]. Figure 8 This will not be elaborated upon here.

[0047] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. An uninterruptible power supply suitable for use in a grid operation monitoring system, characterized in that, The application relates to a battery pack (2), an inverter circuit (3), a voltage equalization module, an AC load interface (6) and a battery management chip (1), wherein the battery pack (2) is connected with the AC load interface (6) through the inverter circuit (3); the battery pack (2) comprises a plurality of battery cells (21), the voltage equalization module comprises a plurality of voltage equalization circuits (5) and a plurality of battery detection circuits (4), the collection end of each battery detection circuit (4) is connected with each battery cell (21) respectively to collect the charging voltage value of the corresponding battery cell (21), and the output end of each battery detection circuit (4) is connected with the battery management chip (1) respectively; two adjacent battery cells (21) are connected through the voltage equalization circuit (5), and the control end of each voltage equalization circuit (5) is connected with the battery management chip (1) to control the current of one battery cell (21) with the charging voltage value exceeding a preset value to flow to another battery cell (21) among the two adjacent battery cells (21).

2. An uninterruptible power supply for use in a grid operating monitoring system according to claim 1, characterized in that The voltage equalization circuit (5) comprises a voltage reduction equalization device (51) and a switch tube (52), one end of the voltage reduction equalization device (51) is connected with one battery cell (21) among the two adjacent battery cells (21), the source and the drain of the switch tube (52) are connected with another battery cell (21) and the other end of the voltage reduction equalization device (51) respectively, and the gate of the switch tube (52) is electrically connected with the battery management chip (1).

3. An uninterruptible power supply for use in a grid operating monitoring system according to claim 2, characterized in that The voltage reduction equalization device (51) comprises a plurality of parallelly-connected voltage reduction resistors.

4. The UPS for grid operating monitoring system as claimed in claim 2 wherein, The voltage equalization circuit (5) further comprises a voltage stabilizing device (53) which is electrically connected with the switch tube (52) and the battery management chip (1) respectively.

5. The UPS for grid operating monitoring system as claimed in claim 1 wherein, The inverter circuit (3) comprises a first filter circuit (31) and an inverter boost circuit (32), the battery pack (2) is connected with the input end of the inverter boost circuit (32) through the first filter circuit (31), and the output end of the inverter boost circuit (32) is connected with the AC load interface (6).

6. An uninterruptible power supply for use in a grid operating monitoring system according to claim 5, characterized in that The inverter boost circuit (32) comprises an inverter switch circuit (321), a driving chip (322) and a boost transformer (323), the input end of the inverter switch circuit (321) is connected with the first filter circuit (31), the control end of the inverter switch circuit (321) is connected with the driving chip (322), the output end of the inverter switch circuit (321) is connected with the input end of the boost transformer (323), and the output end of the boost transformer (323) is connected with the AC load interface (6).

7. An uninterruptible power supply for use in a grid operating monitoring system according to claim 6, characterized in that The inverter boost circuit (32) further comprises a discharge current detection circuit (324) and an amplification circuit (325), the detection end of the discharge current detection circuit (324) is connected with the output end of the boost transformer (323), and the output end of the discharge current detection circuit (324) is connected with the driving chip (322) through the amplification circuit (325).

8. An uninterruptible power supply for use in a grid operating monitoring system according to claim 7, characterized in that, The charging circuit (7) is further provided with an input end adapted to be connected with a commercial power supply, an output end connected with the output end of the step-up transformer (323), and a control end connected with the driving chip (322).

9. An uninterruptible power supply for use in a grid operating monitoring system according to claim 8, characterized in that, The DC output circuit (8) is further provided with an isolation transformer (81), a DC control chip (82), a DC switch circuit (83), and a DC load interface (84), wherein the input end of the isolation transformer (81) is connected with the output end of the first filter circuit (31), the output end of the isolation transformer (81) is connected with the DC load interface (84) through the DC switch circuit (83), and the DC control chip (82) is connected with the DC switch circuit (83) to control the on-off of the DC switch circuit (83).

10. An uninterruptible power supply for use in a grid operating monitoring system according to claim 9, characterized in that, The DC output circuit (8) is further provided with an overcurrent protection device (85), a step-down switch circuit (86), a DC step-down chip (87), a step-down controller (88), a second filter circuit (89), and a fast charging interface (80), wherein the input end of the overcurrent protection device (85) is connected with the output end of the first filter circuit (31), the output end of the overcurrent protection device (85) is connected with the input end of the DC step-down chip (87) through the step-down switch circuit (86), the output end of the DC step-down chip (87) is connected with the fast charging interface (80) through the second filter circuit (89), and the step-down controller (88) is electrically connected with the step-down switch circuit (86) and the DC step-down chip (87), respectively.

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