Uninterruptible power supply

Abstract

An uninterruptible power supply is provided, comprising: an input configured to be electrically connectable to a first AC power source; an output configured to be electrically connectable to one side of an output switch, the other side of the output switch configured to be electrically connectable to a system load; a communication module communicably connectable with other uninterruptible power supplies electrically connected between the first AC power source and the system load, each of the other uninterruptible power supplies having a respective output switch in series between the other uninterruptible power supply and the system load, the communication module configured to obtain operating modes of the other uninterruptible power supplies, the controller configured to determine a switching state of the output switch based on i) at least one of an output voltage, an output frequency of the uninterruptible power supply, and a load current of the system load, ii) an output current of the uninterruptible power supply, and iii) the operating modes of the uninterruptible power supply and the other uninterruptible power supplies.

Description

Technical Field

[0001] This invention relates to the field of power supply, and more specifically to an uninterruptible power supply. Background Technology

[0002] The statements in this section are merely to provide background information in relation to the present invention to aid in understanding the invention, and such background information does not necessarily constitute prior art.

[0003] In modern power supply systems, uninterruptible power systems (UPS) are essential power backup devices, widely used in computers, communication networks, industrial control systems, and industrial equipment requiring continuous operation. Their core function is to provide a stable and uninterrupted power supply to critical equipment, ensuring its normal operation in the event of power outages or abnormalities, and preventing data loss or equipment damage due to power problems.

[0004] Specifically, an uninterruptible power supply (UPS) mainly includes an input terminal, an output terminal, a main branch consisting of an AC-DC converter (rectifier) ​​and a DC-AC converter (inverter), a battery branch consisting of a battery, a DC-DC converter (charging module) to charge the battery, and a DC-DC converter (discharging module) to convert the battery's output voltage to DC, and a discrete bypass from the UPS input terminal to its output terminal. Typically, the UPS input terminal is configured to connect to an AC power source (e.g., mains power), and the output terminal is configured to connect to the system load (e.g., data center equipment) via an output switch. This configuration allows the UPS, such as an online UPS, to rectify AC power into DC power to charge the battery when mains power is normal, while simultaneously converting the DC power back to stable AC power through the inverter to supply power to the system load. When mains power is interrupted, the battery continues to provide power to the system load through the discharging module and the inverter, ensuring uninterrupted operation of the load equipment. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide an uninterruptible power supply, comprising:

[0006] The input terminal is configured to be electrically connected to a first AC power source;

[0007] The output terminal is configured to be electrically connected to one side of an output switch, the other side of which is electrically connected to a system load.

[0008] A communication module is communicatively connected to other uninterruptible power supplies (UPS) electrically connected between the first AC power supply and the system load. Each of the other UPS has a corresponding output switch connected in series with the system load. The communication module is configured to acquire the operating modes of the other UPS, including power conversion mode, battery mode, bypass mode, and power-off mode.

[0009] A controller configured to determine the switching state of the output switch based on at least one of i) the output voltage, output frequency, and load current of the system load; ii) the output current of the uninterruptible power supply; and iii) the operating modes of the uninterruptible power supply and the other uninterruptible power supplies.

[0010] According to the uninterruptible power supply of the present invention, the controller is further configured to: determine the switching state of the output switch based on i) any two or three of the output voltage, output frequency and load current of the system load of the uninterruptible power supply, ii) the output current of the uninterruptible power supply and iii) the operating modes of the uninterruptible power supply and the other uninterruptible power supplies.

[0011] According to the uninterruptible power supply of the present invention, the controller is further configured to: when the uninterruptible power supply and the other uninterruptible power supply are in power conversion mode or battery mode, respectively compare the load current with a first current threshold and the output current with a second current threshold, and determine that the switching state of the output switch is open when the load current is greater than the first current threshold and the output current is less than the second current threshold.

[0012] According to the uninterruptible power supply of the present invention, the controller is further configured to: when the uninterruptible power supply and the other uninterruptible power supply are in power conversion mode or battery mode, respectively compare the output frequency with a first frequency threshold and the output frequency with a second frequency threshold, and determine that the switching state of the output switch is open when the output frequency is less than the first frequency threshold or the output frequency is greater than the second frequency threshold.

[0013] The uninterruptible power supply according to the present invention further includes a discrete bypass, wherein the input side of the discrete bypass is electrically connected to a second AC power supply and the output side is electrically connected to the output terminal; wherein the controller is further configured to: compare the bypass frequency of the discrete bypass with a first frequency range, and determine that the switching state of the output switch is open when the output frequency is less than the first frequency threshold or the output frequency is greater than the second frequency threshold and the bypass frequency is within the first frequency range.

[0014] According to the uninterruptible power supply of the present invention, the controller is further configured to: compare the output current with a second current threshold, and determine that the switching state of the output switch is open when the output frequency is less than the first frequency threshold or when the output frequency is greater than the second frequency threshold and the output current is less than the second current threshold.

[0015] According to the uninterruptible power supply of the present invention, the controller is further configured to: when the uninterruptible power supply is in a power-off mode and some of the other uninterruptible power supplies are in a power conversion mode or a battery mode, compare the output voltage with a first voltage threshold and the output current with a second current threshold, and determine that the switching state of the output switch is open when the output voltage is less than the first voltage threshold and the output current is less than the second current threshold.

[0016] According to the uninterruptible power supply of the present invention, the controller is further configured to periodically determine the switching state of the output switch according to a preset judgment period.

[0017] According to the uninterruptible power supply of the present invention, the controller is further configured to instruct the user on the on / off state of the output switch after determining at least twice consecutively that the on / off state of the output switch is open.

[0018] According to the uninterruptible power supply of the present invention, the first current threshold is the sum of the rated output currents of the uninterruptible power supply and the other uninterruptible power supplies, the second current threshold is determined based on the rated output current of the uninterruptible power supply, the first frequency threshold and the second frequency threshold are determined based on the output frequency of the first AC power supply, and the first frequency range is determined based on the output frequency of the second AC power supply.

[0019] This invention acquires key parameters such as the output current, output voltage, output frequency, bypass frequency, load current of the system load, and the operating modes of other uninterruptible power supplies (UPS) in a parallel UPS system. It then constructs a dynamic decision-making mechanism based on multi-dimensional parameter collaborative analysis, achieving accurate determination of the output switch status. This innovative breakthrough overcomes multiple bottlenecks in existing output switch status detection technologies in parallel UPS systems. Compared to existing technologies, this invention, based on the characteristics of the UPS itself, uses software algorithms to replace hardware sensors. This not only eliminates technical obstacles in equipment adaptation, installation, and maintenance, saving related manpower and material resources, but also fundamentally overcomes the technical defects of hardware sensors, such as signal delay, poor contact, and weak anti-interference capabilities. It can achieve rapid and accurate determination of the output switch's switching status. Attached Figure Description

[0020] The embodiments of the present invention will be further described below with reference to the accompanying drawings, wherein:

[0021] Figure 1 A circuit diagram of a UPS and a UPS parallel system thereof, according to an embodiment of the present invention, is shown.

[0022] Figure 2 A circuit diagram of a UPS and its parallel system according to another embodiment of the present invention is shown;

[0023] Figure 3A A partial flowchart of a control method for an uninterruptible power supply according to an embodiment of the present invention is shown.

[0024] Figure 3B Another part of the flowchart of a control method for an uninterruptible power supply according to an embodiment of the present invention is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0027] The block diagrams shown in the attached figures are merely functional entities and do not necessarily correspond to physically independent entities. These functional entities can be implemented in software, within one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0028] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0029] With the deep integration of information technology and industrial automation, critical infrastructure places higher demands on the reliability and capacity of power supply systems. Power supply solutions based on multiple uninterruptible power supplies (UPS) connected in parallel have been widely applied in data centers, communication hubs, and industrial production lines. Compared to the single-point-of-failure risk of traditional single-unit UPS systems, N+1 or multi-unit parallel topologies significantly improve power continuity through redundant design. In a parallel system of multiple UPS units (hereinafter referred to as a UPS parallel system), the corresponding output switches connected in series between each UPS and the system load serve to control circuit on / off, provide overload protection, short-circuit protection, isolate faults, facilitate system debugging, testing, and maintenance, and improve system flexibility. They are key components in a UPS parallel system. For example, when a UPS fails, the corresponding output switch needs to be quickly disconnected to isolate the faulty UPS; after the fault is repaired, the output switch can be closed to seamlessly connect the UPS back into the UPS parallel system.

[0030] Through long-term practice, the inventors discovered that current technologies for detecting the switch status of output switches in parallel UPS systems suffer from multiple technical bottlenecks. First, because output switches are generally selected and installed independently by users, differences in models from different brands, incompatible interface standards, and diverse installation methods make it difficult to standardize and adapt the sensors or detection circuits used to detect their switch status, resulting in unsatisfactory accuracy in switch status detection. Second, traditional detection schemes rely on passive detection using sensors installed at the physical locations of the corresponding output switches, which has significant drawbacks—each UPS requires an independent sensor and detection circuit, not only doubling hardware costs but also exposing long-distance signal cables exposed to complex environments to mechanical damage (such as rodent damage, vibration abrasion), electromagnetic interference, or environmental corrosion, causing signal transmission interruptions. More importantly, the implementation of traditional detection schemes is highly dependent on early intervention during the power distribution system upgrade phase. If the UPS supplier fails to participate in the power distribution network planning, it will be difficult to install and configure sensors at the corresponding physical locations of the output switches later. In addition, the independent detection channel set up for each UPS not only causes the repeated occupation of detection circuit resources, but also exacerbates the consumption of space resources and the complexity of wiring due to the parallel laying of multiple signal transmission lines.

[0031] In view of the above challenges in detecting the switching status of the output switches in a parallel UPS system, this invention proposes an innovative uninterruptible power supply and its control method, which can break through the dependence of traditional solutions on physical sensors, and achieve hardware cost optimization and intensive use of space resources while ensuring reliability.

[0032] Figure 1 A circuit diagram of a UPS and its parallel system according to an embodiment of the present invention is shown. Figure 1 As shown, the UPS parallel system 10 includes n uninterruptible power supplies (UPS 1-UPS n) connected in parallel between the first AC power supply 12 and the system load 11. Each of the n UPS 1-UPS n has a corresponding output switch S1-Sn connected in series between its output terminal and the system load 11. Typically, the UPS 1-UPS n are provided by the UPS manufacturer, while the output switches S1-Sn are provided by the user of the UPS parallel system. For example... Figure 1 As shown, taking UPS 1 as an example, it includes an input terminal IN1, an output terminal OUT1, a main branch 101, a battery branch 102, a separate bypass 103, a controller 107, and a communication module CAN1. The input terminal IN1 of UPS 1 is configured to be electrically connected to a first AC power source 12 (e.g., mains power), and its output terminal OUT1 is configured to be electrically connected to one side of the output switch S1. The other side of the output switch S1 is configured to be electrically connected to the system load 11. The communication module CAN1 can communicatively connect to other uninterruptible power supplies (e.g., UPS2-UPSn) electrically connected between the first AC power source 12 and the system load 11. Figure 1 As shown, in this embodiment, the communication module CAN1 is wired to the other uninterruptible power supplies (UPS 2-UPS n). The communication module CAN1 is configured to acquire the operating modes of the other UPS 2-UPS n. The other UPS 2-UPS n have a similar configuration to UPS 1. The controller 107 is configured to control UPS 1 and determine the switching state of the output switch S1 based on the following parameters:

[0033] i) At least one, any two, or three of the following: the output voltage U1, the output frequency f1, and the load current Iload of the system load 11;

[0034] ii) The output current I1 of the uninterruptible power supply UPS 1; and

[0035] iii) Operating modes of UPS 1 and other UPS 2-UPS n.

[0036] The inventors discovered that these parameters can effectively determine the state of output switch S1 without the need for additional sensors to detect its switching status. When the switch is closed, the current UPS output voltage U1 and frequency f1 should match the load side, and the output current I1 should flow normally. If the current UPS has voltage but no current (I1=0) or the current is too low, or if it contradicts the expected operating state of the current UPS, it indicates that the output switch may be open. Therefore, by analyzing the logical relationship between electrical parameters (voltage, current, frequency) and the system operating mode, reliable determination of the switch state can be achieved without physical sensors, thereby reducing costs and simplifying the detection structure.

[0037] In some embodiments of the present invention, preferably, the controller 107 is configured to acquire or collect the above parameters in real time.

[0038] In some embodiments of the present invention, preferably, the communication module CAN1 of the uninterruptible power supply 1 is wirelessly connected to other uninterruptible power supplies. The communication module CAN1 obtains the operating modes of other uninterruptible power supplies by wirelessly communicating with them. Thus, the uninterruptible power supply 1 can obtain the operating mode information of other uninterruptible power supplies in real time and efficiently, without complex wiring, greatly reducing installation costs and maintenance difficulty. In some embodiments of the present invention, the main branch 101 includes a rectifier module 1010 and an inverter module 1011 connected sequentially between the input terminal IN1 and the output terminal OUT1 of the UPS 1. The battery branch 102 includes a charging / discharging module 1020 and a battery 1021, and the battery branch 102 is configured to be electrically connected to the node between the rectifier module 1010 and the inverter module 1011. The discrete bypass 103 includes a bypass switching switch 1031 for controlling its on and off states, and the discrete bypass 103 is configured to be connected in parallel with the main branch 101.

[0039] The operating modes of an uninterruptible power supply (UPS) typically include power conversion mode, battery mode, bypass mode, and shutdown mode. When UPS 1 is in power conversion mode, the rectifier module 1010 is configured to convert the AC power input from the first AC power source 12 into DC power and supply it to the inverter module 1011 and the charge / discharge module 1020. The inverter module 1011 is configured to convert the received DC power into AC power and supply it to the system load 11. Simultaneously, the charge / discharge module 1020 is configured to convert the received DC power into DC power and charge the battery 1021. When UPS 1 is in battery mode, the charge / discharge module 1020 is configured to convert the DC power output from the battery 1021 into DC power and supply it to the inverter module 1011. The inverter module 1011 is configured to convert the input DC power into AC power and supply it to the load 11. When UPS 1 is in bypass mode, bypass switch 1031 is closed, and the first AC power supply 12 supplies power to the system load 11 via discrete bypass 103. Current no longer flows through the main branch 101 and battery branch 102. When UPS 1 is in shutdown mode, UPS 1 stops working.

[0040] In some embodiments of the present invention, the controller 107 may also be configured to: when the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n are in power conversion mode or battery mode, compare the load current Iload with the first current threshold Ith1 and the output current I1 with the second current threshold Ith2 respectively, and determine that the switching state of the output switch S1 is open when the load current Iload is greater than the first current threshold Ith1 and the output current I1 is less than the second current threshold Ith2.

[0041] In some embodiments of the present invention, the first current threshold Ith1 can be the sum of the rated output currents of the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n. Preferably, Ith1 = n*I, where n is the number of UPSs connected in parallel in the UPS parallel system 10, and I is the rated current of the UPS in the UPS parallel system 10. The second current threshold Ith2 can be determined based on the rated output current of the uninterruptible power supply UPS 1. Preferably, Ith2 = 2%*I, where I is the rated current of the uninterruptible power supply UPS 1.

[0042] In some embodiments of the present invention, the controller 107 may also be configured to: when the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n are in power conversion mode or battery mode, compare the output frequency f1 with a first frequency threshold fth1 and the output frequency f1 with a second frequency threshold fth2 respectively, and determine that the switching state of the output switch S1 is open when the output frequency f1 is less than the first frequency threshold fth1 or the output frequency f1 is greater than the second frequency threshold fth2.

[0043] In some embodiments of the present invention, the first frequency threshold fth1 and the second frequency threshold fth2 can be determined based on the output frequency of the first AC power supply 12, and the first frequency threshold fth1 is less than the second frequency threshold fth2. Preferably, fth1 = f1 * (1 - m) and fth2 = f1 * (1 + m), where f1 is the output frequency of the first AC power supply 12, and m can be determined based on the actual operating conditions of the UPS parallel system 10 or user requirements, for example, m can be 2%, 4%, or 5%, etc.

[0044] In some embodiments of the present invention, the controller 107 may also be configured to: when the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n are in power conversion mode or battery mode, compare the output frequency f1 with a first frequency threshold fth1, the output frequency f1 with a second frequency threshold fth2, and the bypass frequency fp of the discrete bypass 103 with a first frequency range fr, and determine that the switching state of the output switch S1 is open when the output frequency f1 is less than the first frequency threshold fth1 or the output frequency f1 is greater than the second frequency threshold fth2 and the bypass frequency fp is within the first frequency range fr. Here, the bypass frequency fp is the input frequency of the discrete bypass 103 obtained by the controller 107. In this embodiment, the bypass frequency fp is the output frequency of the first AC power supply 12.

[0045] Figure 2 A circuit diagram of a UPS and its parallel system according to another embodiment of the present invention is shown. Wherein, as... Figure 2 As shown, the input side of the discrete bypass 103 of UPS 1 is electrically connected to the second AC power supply 13, and the output side is electrically connected to the output terminal OUT1. In this embodiment, the bypass frequency fp is the output frequency of the second AC power supply 13.

[0046] In some embodiments of the present invention, the controller 107 may also be configured to: when the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n are in power conversion mode or battery mode, compare the output frequency f1 with a first frequency threshold fth1, the output frequency f1 with a second frequency threshold fth2, and the output current I1 with a second current threshold Ith2, and determine that the switching state of the output switch S1 is open when the output frequency f1 is less than the first frequency threshold fth1 or the output frequency f1 is greater than the second frequency threshold fth2 and the output current I1 is less than the second current threshold Ith2. When the output switch S1 is open, the electrical connection between UPS 1 and the system load 11 is cut off, its output current I1 will be significantly reduced (close to zero), and it cannot participate in load power distribution. At this time, other parallel UPSs (such as UPS 2-UPS n) will actively respond to load demand by increasing the output frequency (e.g., entering overload frequency regulation mode) to increase power output and maintain system frequency stability. If controller 107 detects that the output frequency f1 of UPS 1 exceeds the normal threshold range due to disconnection from the load (e.g., f1 < fth1 or f1 > fth2), and its output current I1 is lower than the threshold Ith2 due to disconnection of the associated path, then it can be determined that S1 is in the disconnected state. This mechanism utilizes the frequency coupling characteristics between UPSs in a parallel system and the correlation logic of the load dynamic response, and can achieve state diagnosis without relying on physical sensors.

[0047] In some embodiments of the present invention, the controller 107 may also be configured to: when the uninterruptible power supply UPS 1 and other uninterruptible power supplies UPS 2-UPS n are in power conversion mode or battery mode, compare the output frequency f1 with a first frequency threshold fth1, the output frequency f1 with a second frequency threshold fth2, the bypass frequency fp of the discrete bypass 103 with a first frequency range fr, and the output current I1 with a second current threshold Ith2, and determine that the switching state of the output switch S1 is open when the above comparisons simultaneously meet the following requirements:

[0048] i) The output frequency f1 is less than the first frequency threshold fth1 or the output frequency f1 is greater than the second frequency threshold fth2;

[0049] ii) The bypass frequency fp is within the first frequency range fr; and

[0050] iii) The output current I1 is less than the second current threshold Ith2.

[0051] In this solution, adding the judgment on the bypass frequency fp is to eliminate the interference of input circuit abnormalities (such as mains frequency fluctuations) on switch state detection. For example, when the UPS is in the power conversion mode, if the bypass frequency fp of the input first AC power source 12 (such as the mains) is within the normal range fr, it indicates that there is no significant abnormality on the input side (such as stable mains frequency). At this time, if the output frequency f1 of UPS 1 deviates from the threshold (f1<fth1 or f1>fth2) and the output current I1 is lower than the threshold Ith2, the frequency offset caused by the input side problem can be excluded, and it is further clarified that the abnormality originates from the disconnection of the output switch S1. By correlating the logical relationship between the bypass frequency and the UPS output frequency, the robustness of state judgment can be improved, and misjudgments caused by transient fluctuations on the input side (such as short-term frequency disturbances) can be avoided.

[0052] In some embodiments of the present invention, the first frequency range fr is related to the rated output frequency of the AC power source connected to the input side of the discrete bypass 103.

[0053] In some embodiments of the present invention, the controller 107 may further be configured to: when the uninterruptible power supply UPS 1 is in the shutdown mode and some of the other uninterruptible power supplies UPS 2 to UPS n are in the power conversion mode or the battery mode, respectively compare the output voltage U1 with the first voltage threshold Uth1, and the output current I1 with the second current threshold Ith2, and when the output voltage U1 is less than the first voltage threshold Uth1 and the output current I1 is less than the second current threshold Ith2, determine that the switch state of the output switch S1 is open.

[0054] In some embodiments of the present invention, the first voltage threshold Uth1 may be determined based on the actual working condition of the UPS parallel system 10 or user requirements, for example, 100V.

[0055] In some embodiments of the present invention, the controller 107 may be configured to determine the switch state of the output switch S1 based on a user's instruction; the controller 107 may also be configured to periodically determine the switch state of the output switch S1 according to a preset judgment period T, that is, the controller 107 determines the switch state of the output switch S1 once within each judgment period T. The judgment period T may be determined based on the actual working condition of the UPS parallel system 10 or user requirements, for example, 500ms or 1s.

[0056] In some embodiments of the present invention, the controller 107 may further be configured to, after determining that the switch state of the output switch S1 is open for at least two consecutive times, indicate to the user the switch state of the output switch S1. For example, the controller 107 will output an indication to the user that the switch state of the output switch S1 is open only after determining that the switch state of the output switch S1 is open for three consecutive times.

[0057] Embodiments of the present invention also provide a control method for an uninterruptible power supply (UPS), wherein the control method can be used to determine the output switch (e.g., such as...) connected in series between the output terminal of the UPS and the system load. Figure 1 or Figure 2 The switching state of the output switch S1 shown. This control method includes the following steps:

[0058] Step 1: Obtain the operating mode, output current I1, output voltage U1, and output frequency f1 of the uninterruptible power supply UPS 1, as well as the load current Iload of the system load 11;

[0059] Step Two: Obtain the operating mode of the other uninterruptible power supply UPS 2-UPS n by means of the communication module CAN1, which is communicatively connected to the other uninterruptible power supply UPS 2-UPS n, which is electrically connected between the first AC power supply 12 and the system load 11; and

[0060] Step 3: Determine the switching state of output switch S1 based on at least one of i) the output voltage U1, output frequency f1 and load current Iload of system load 11, ii) the output current I1 of uninterruptible power supply UPS 1 and iii) the operating modes of uninterruptible power supply UPS 1 and other uninterruptible power supply UPS 2-UPS n.

[0061] Figure 3 shows a flowchart of a control method for an uninterruptible power supply according to an embodiment of the present invention. As shown in Figure 3, the control method includes the following steps:

[0062] S10: Obtain the operating mode of UPS 1-UPS n for uninterruptible power supply.

[0063] S101: Determine whether UPS 1 is in shutdown mode and some of the other uninterruptible power supplies (UPS 2-UPS n) are in power conversion mode or battery mode? If yes, proceed to step S102; if no, proceed to step S201.

[0064] S102: Obtain the output voltage U1 and output current I1 of the uninterruptible power supply UPS 1.

[0065] S103: Compare the output voltage U1 with the first voltage threshold Uth1.

[0066] S104: Determine whether the output voltage U1 is less than the first voltage threshold Uth1. If yes, proceed to step S105; otherwise, proceed to step S201.

[0067] S105: Compare the output current I1 with the second current threshold Ith2.

[0068] S106: Determine whether the output current I1 is less than the second current threshold Ith2. If yes, proceed to step S107; otherwise, proceed to step S201.

[0069] S107: Determine that the switch state of output switch S1 is open.

[0070] S201: Determine whether all uninterruptible power supplies UPS 1-UPS n are in power conversion mode or battery mode? If yes, proceed to step S202; otherwise, end the process.

[0071] S202: Obtain the load current Iload of the parallel system (UPS 1-UPS n) and the output current I1 of the unit (UPS 1).

[0072] S203: Compare the load current Iload with the first current threshold Ith1, and the output current I1 with the second current threshold Ith2.

[0073] S204: Determine whether the load current Iload is greater than the first current threshold Ith1 and the output current I1 is less than the second current threshold Ith2? If yes, proceed to step S205; otherwise, proceed to step S301.

[0074] S205: Determine that the switch state of output switch S1 is open.

[0075] S301: Obtain the output frequency f1 of the uninterruptible power supply UPS 1 and the bypass frequency fp of its discrete bypass 103.

[0076] S302: Compare the output frequency f1 with the first frequency threshold fth1, the output frequency f1 with the second frequency threshold fth2, and the bypass frequency fp of the discrete bypass 103 with the first frequency range fr.

[0077] S303: Determine whether the output frequency f1 is less than the first frequency threshold fth1 or the output frequency f1 is greater than the second frequency threshold fth2 and the bypass frequency fp is within the first frequency range fr? If yes, proceed to step S304; otherwise, end the process.

[0078] S304: Determine that the switch state of output switch S1 is open.

[0079] In embodiments of the present invention, steps S101-S107, S201-S205, and S301-S304 can be arbitrarily combined or rearranged according to actual needs. For example, in some embodiments of the present invention, the switching state of output switch S1 is determined by executing steps S10, S101-S107, and S201-S205; in other embodiments, the switching state of output switch S1 is determined by executing steps S10 and S201-S205; and in still other embodiments, the switching state of output switch S1 is determined by executing steps S10, S101-S107, S201-S205, and S301-S304. Thus, by flexibly combining different detection logics, the needs of different application scenarios can be adapted, improving system security (e.g., multi-mode detection) and optimizing execution efficiency (e.g., detecting only key modes). Simultaneously, the modular design allows users to select appropriate detection strategies according to actual needs, balancing reliability and flexibility.

[0080] This invention provides an uninterruptible power supply (UPS) and its control method, making an innovative breakthrough in addressing multiple bottlenecks in existing UPS parallel system output switch status detection technology. By acquiring key parameters such as the UPS's output current, output voltage, output frequency, bypass frequency, system load current, and the operating modes of other UPSs in the parallel UPS system, this invention constructs a dynamic decision-making mechanism based on multi-dimensional parameter collaborative analysis, achieving accurate determination of the output switch status. Compared to existing technologies, this invention, based on the inherent characteristics of the UPS, replaces hardware sensors with software algorithms. This not only eliminates technical obstacles in equipment adaptation, installation, and maintenance, saving related manpower and material resources, but also fundamentally overcomes the technical defects of hardware sensors, such as signal delay, poor contact, and weak anti-interference capabilities, enabling rapid and accurate determination of the output switch's switching status.

[0081] References to "various embodiments," "some embodiments," "one embodiment," or "embodiment," etc., in this specification refer to a specific feature, structure, or property described in connection with the said embodiment, included in at least one embodiment. Therefore, the appearance of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment," etc., throughout this specification does not necessarily refer to the same embodiment. Furthermore, specific features, structures, or properties can be combined in any suitable manner in one or more embodiments. Therefore, a specific feature, structure, or property shown or described in connection with one embodiment can be combined, in whole or in part, with features, structures, or properties of one or more other embodiments without limitation, provided that the combination is not illogical or inoperable.

[0082] The terms "comprising," "having," and similar expressions used in this specification are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus. "A" or "an" does not exclude multiple instances. Furthermore, the elements in the accompanying drawings are for illustrative purposes only and are not drawn to scale.

[0083] While the present invention has been described through preferred embodiments, it is not limited to the embodiments described herein, and various changes and modifications are made without departing from the scope of the invention.

Claims

1. An uninterruptible power supply, comprising: The input terminal is configured to be electrically connected to a first AC power source; The output terminal is configured to be electrically connected to one side of an output switch, the other side of which is configured to be electrically connected to a system load. The communication module is communicatively connected to other uninterruptible power supplies (UPS) electrically connected between the first AC power supply and the system load. Each of the other UPSs is connected in series with a corresponding output switch to the system load. The communication module is configured to acquire the operating modes of the other UPSs, including power conversion mode, battery mode, bypass mode, and power-off mode. as well as A controller configured to determine the switching state of the output switch based on at least one of i) the output voltage, output frequency, and load current of the system load; ii) the output current of the uninterruptible power supply; and iii) the operating modes of the uninterruptible power supply and the other uninterruptible power supplies.

2. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to: The switching state of the output switch is determined based on any two or three of the following: i) the output voltage and output frequency of the uninterruptible power supply and the load current of the system load; ii) the output current of the uninterruptible power supply; and iii) the operating modes of the uninterruptible power supply and the other uninterruptible power supplies.

3. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to: When the uninterruptible power supply and the other uninterruptible power supply are in power conversion mode or battery mode, the load current is compared with a first current threshold and the output current is compared with a second current threshold, and when the load current is greater than the first current threshold and the output current is less than the second current threshold, the switch state of the output switch is determined to be open.

4. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to: When the uninterruptible power supply and the other uninterruptible power supply are in power conversion mode or battery mode, the output frequency is compared with a first frequency threshold and a second frequency threshold, respectively. When the output frequency is less than the first frequency threshold or the output frequency is greater than the second frequency threshold, the switch state of the output switch is determined to be open.

5. The uninterruptible power supply according to claim 4 further includes a discrete bypass, wherein the input side of the discrete bypass is electrically connected to a second AC power supply, and the output side is electrically connected to the output terminal; wherein, The controller is also configured to: The bypass frequency of the discrete bypass is compared with the first frequency range, and when the output frequency is less than the first frequency threshold or the output frequency is greater than the second frequency threshold and the bypass frequency is within the first frequency range, the switching state of the output switch is determined to be open.

6. The uninterruptible power supply according to claim 4, wherein, The controller is also configured to: The output current is compared with the second current threshold, and when the output frequency is less than the first frequency threshold or the output frequency is greater than the second frequency threshold and the output current is less than the second current threshold, the switch state of the output switch is determined to be open.

7. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to: When the uninterruptible power supply is in shutdown mode and some of the other uninterruptible power supplies are in power conversion mode or battery mode, the output voltage is compared with a first voltage threshold and the output current is compared with a second current threshold. When the output voltage is less than the first voltage threshold and the output current is less than the second current threshold, the switch state of the output switch is determined to be open.

8. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to periodically determine the switching state of the output switch according to a preset judgment cycle.

9. The uninterruptible power supply according to claim 1, wherein, The controller is also configured to instruct the user on / off state of the output switch after determining at least twice consecutively that the output switch is in an open state.

10. The uninterruptible power supply according to claim 1, wherein, The first current threshold is the sum of the rated output currents of the uninterruptible power supply and the other uninterruptible power supplies; the second current threshold is determined based on the rated output current of the uninterruptible power supply; the first frequency threshold and the second frequency threshold are determined based on the output frequency of the first AC power supply; and the first frequency range is determined based on the output frequency of the second AC power supply.

Images