Power supply control method and uninterruptible power supply system

Abstract

The application discloses a power supply control method and an uninterruptible power supply system, and relates to the technical field of power supply. In the power supply control method, a direct current input voltage is detected, and when it is determined that the input voltage is abnormal based on the direct current input voltage, the input power supply straight-through path is turned off, the standby power supply path is turned on, the output switch circuit is controlled to be turned on to switch to super capacitor group power supply, a power-off signal is sent to the load to trigger the load to perform a shutdown action, and a shutdown confirmation signal is sent; the state feedback voltage of the load is detected, and when it is determined that the load has performed the shutdown action based on the state feedback voltage and the shutdown confirmation signal is received, the output switch circuit is controlled to be turned off; when it is determined that the load has performed the shutdown action based on the state feedback voltage and an active shutdown signal is received, the output switch circuit is controlled to be turned on, the input power supply straight-through path is turned on, and the standby power supply path is turned off. The application aims to improve the safety problems caused by the insufficient flexibility of power-on restart of the uninterruptible power supply system and the false triggering of restart.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, and in particular to a power supply control method and an uninterruptible power supply system. Background Technology

[0002] As the core equipment ensuring the continuous operation or safe shutdown of critical loads during mains power anomalies, the intelligence level of the power restoration logic of uninterruptible power supply (UPS) systems directly affects user experience and system security. In traditional solutions, the triggering mechanism of the "power-on self-start" function in UPS systems has flaws. It relies on the physical process of the supercapacitor, acting as a backup power source, completely depleting its charge, causing the output voltage to drop to a point where it can no longer supply power. When the mains power experiences a brief interruption and then quickly recovers, and the supercapacitor still has residual charge, the triggering condition for "power-on self-start" is not met, and the system cannot actively perform a power restoration operation. It can only rely on manual intervention to restart, limiting the flexibility and automation of system recovery. Furthermore, traditional solutions cannot effectively identify the specific reasons for load shutdown, i.e., they cannot distinguish between a user-initiated active shutdown and a protective shutdown triggered by a mains power anomaly. This leads to the system performing a power-on operation after mains power is restored, which can easily cause unexpected restarts due to mains power fluctuations during user-initiated shutdown maintenance. This not only violates the user's operational intentions but may also cause data conflicts or hardware maintenance security risks. Therefore, there is an urgent need for a power supply control method to improve the lack of flexibility in power-on restart of uninterruptible power supply systems and the safety problems caused by accidental restarts. Summary of the Invention

[0003] The main objective of this invention is to propose a power supply control method and an uninterruptible power supply system, which aims to improve the power-on restart flexibility of uninterruptible power supply systems and the safety problems caused by accidental restarts, thereby improving the power supply reliability and safety of uninterruptible power supply systems.

[0004] To achieve the above objectives, this invention proposes a power supply control method applied to an uninterruptible power supply (UPS) system. The UPS system includes a mains input terminal, a supercapacitor bank, an output switching circuit, and a power supply terminal for connecting a load. The mains input terminal is electrically connected to the first input terminal of the output switching circuit via an input power direct path. The input terminal of the supercapacitor bank is electrically connected to the mains input terminal. The output terminal of the supercapacitor bank is electrically connected to the second input terminal of the output switching circuit via a backup power path. The output terminal of the output switching circuit is electrically connected to the power supply terminal. The power supply control method includes: The system detects the DC input voltage connected to the mains input terminal, and if it determines that the input voltage is abnormal based on the DC input voltage, it shuts off the input power direct path, connects the backup power path, controls the output switching circuit to be in the conducting state to switch to the supercapacitor bank power supply, and sends a power failure signal to the load to trigger the load to perform a shutdown action, and sends a shutdown confirmation signal. The load status feedback voltage is detected. If it is determined based on the status feedback voltage that the load has completed the shutdown action and the shutdown confirmation signal is received, the output switch circuit is controlled to be in the off state so that the input voltage of the load drops to a preset first voltage value. The status feedback voltage is related to the load's power-on / power-off state. When the load has completed the shutdown action based on the state feedback voltage and an active shutdown signal is received from the load, the output switch circuit is controlled to be in the on state, and the input power direct path is turned on while the backup power path is turned off.

[0005] In one embodiment, after detecting the DC input voltage connected to the mains input terminal, the power supply control method further includes: If the DC input voltage is less than or equal to a preset second voltage value, an input voltage anomaly is determined. If the DC input voltage is greater than a preset third voltage value, the input voltage is determined to be normal. The preset second voltage value is less than the preset third voltage value.

[0006] In one embodiment, after controlling the output switching circuit to be in the off state when the power supply control method further includes: (1) after determining that the load has completed the shutdown action based on the state feedback voltage and receiving the shutdown confirmation signal. If, based on the DC input voltage, it is determined that the input voltage has returned to normal, the output switching circuit is controlled to be in the ON state, thus opening the direct input power supply path and shutting off the backup power supply path. In one embodiment, after controlling the output switching circuit to be in the OFF state, the power supply control method further includes: The voltage at the output terminal of the output switch circuit is detected to obtain the load supply voltage; If, based on the DC input voltage, it is determined that the input voltage has returned to normal, and it is determined that the load power supply voltage has dropped to the preset first voltage value, the duration for which the output switch circuit is turned off is controlled to reach the preset delay duration. After the output switch circuit is turned off for a preset delay period, the output switch circuit is turned on and the input power supply direct path is opened, while the backup power supply path is turned off, so that the load can perform a power-on or power-restart action.

[0007] In one embodiment, the preset first voltage value is equal to 0.

[0008] In one embodiment, after determining that the load has completed the shutdown action based on the state feedback voltage and receiving an active shutdown signal from the load, the power supply control method further includes: ... ... After controlling the output switching circuit to be in the ON state, and opening the input power direct path while shutting off the backup power path... If an abnormal input voltage is determined based on the DC input voltage, the input power direct path is shut off, and the backup power path is activated to switch to power supply from the supercapacitor bank.

[0009] In one embodiment, during the switching to supercapacitor bank power supply, the power supply control method further includes: Detect the output voltage of the supercapacitor bank; If the output voltage of the supercapacitor bank is determined to be less than or equal to a preset shutdown voltage threshold, the backup power supply path is shut off, and the output switching circuit is controlled to be in the off state to cut off the input voltage of the load. When the output voltage of the supercapacitor bank is greater than or equal to the preset power-on voltage threshold, the backup power supply path is turned on, and the output switching circuit is controlled to be in the on state to provide input voltage to the load. Wherein, the preset shutdown voltage threshold is less than the preset power-on voltage threshold.

[0010] In one embodiment, the power supply control method further includes: If the input voltage is determined to be normal based on the DC input voltage, the supercapacitor bank is controlled to charge until the output voltage of the supercapacitor bank reaches the preset upper limit of the charging voltage, at which point the supercapacitor bank is controlled to stop charging.

[0011] The present invention also proposes an uninterruptible power supply system, characterized in that the uninterruptible power supply system comprises: A control device, the control device being configured to execute the power supply control method described in any of the preceding claims; AC power input terminal; A supercapacitor bank is composed of multiple supercapacitors connected in series, and the input terminal of the supercapacitor bank is electrically connected to the mains power input terminal. The power supply end is used to connect the load; An output switch circuit, wherein the controlled terminal of the output switch circuit is electrically connected to the control device, and the output terminal of the output switch circuit is electrically connected to the power supply terminal; A first switching circuit, wherein a first terminal of the first switching circuit is electrically connected to the mains input terminal, a second terminal of the first switching circuit is electrically connected to the first input terminal of the output switching circuit, and a controlled terminal of the first switching circuit is electrically connected to the control device, wherein the mains input terminal, the first switching circuit, and the first input terminal constitute a direct input power supply path; The second switching circuit has a first terminal electrically connected to the output terminal of the supercapacitor bank, a second terminal electrically connected to the second input terminal of the output switching circuit, and a controlled terminal electrically connected to the control device. The output terminal of the supercapacitor bank, the second switching circuit, and the second input terminal constitute a backup power supply path. The control device is used to control the first switching circuit to be in the on state so as to conduct the input power direct path, and to control the second switching circuit to be in the off state so as to shut off the backup power path. Alternatively, it can be used to control the second switching circuit to be in a conducting state to connect the backup power supply path, and to control the first switching circuit to be in a turning-off state to disconnect the input power supply direct path. In one embodiment, the control device includes: The main control module is electrically connected to the first switch circuit, the second switch circuit, and the output switch circuit, respectively. An input voltage sampling module is used to detect the DC input voltage connected to the mains input terminal and output a first voltage signal to the main control module, so that the main control module can determine the magnitude of the DC input voltage based on the first voltage signal. A supercapacitor voltage sampling module is used to detect the voltage across the supercapacitor bank and output a second voltage signal to the main control module, so that the main control module can determine the output voltage of the supercapacitor bank based on the second voltage signal. The output voltage sampling module is used to collect the voltage connected to the first input terminal or the second input terminal of the output switching circuit and output it to the main control module. The final output voltage sampling module is used to collect the voltage at the output terminal of the output switching circuit and output a third voltage signal to the main control module so that the main control module can determine the load supply voltage based on the third voltage signal. The status voltage sampling module is used to detect the critical power rail voltage of the load and output a fourth voltage signal to the main control module so that the main control module can determine the status feedback voltage of the load based on the fourth voltage signal.

[0012] In practical applications, the introduction of dual judgment logic based on critical power rail monitoring and GPO signal feedback not only proactively executes output switching operations based on the actual operating status of the load, eliminating the limitation of system restart caused by residual supercapacitor charge, and improving the recovery flexibility and automated response capability of the uninterruptible power supply system under mains power fluctuation scenarios; it also accurately identifies user-initiated shutdown and abnormal power outage shutdown situations, and executes differentiated power supply strategies accordingly, effectively reducing the safety risk of unexpected equipment restarts after user-initiated shutdown. Thus, the operational reliability of the uninterruptible power supply system and the user experience are improved. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0014] Figure 1 This is a flowchart of an embodiment of the power supply control method of the present invention; Figure 2 This is a flowchart of another embodiment of the power supply control method of the present invention; Figure 3 This is a flowchart of another embodiment of the power supply control method of the present invention; Figure 4 This is a flowchart of another embodiment of the power supply control method of the present invention; Figure 5 This is a schematic diagram of a module of an embodiment of the uninterruptible power supply system of the present invention; Figure 6 This is a schematic diagram of a module of another embodiment of the uninterruptible power supply system of the present invention; Figure 7 This is a flowchart of another embodiment of the power supply control method of the present invention; Figure 8 This is a flowchart of another embodiment of the power supply control method of the present invention; Figure 9 This is a flowchart of another embodiment of the power supply control method of the present invention.

[0015] Explanation of icon numbers: 10. Control device; 20. Mains input terminal; 30. Supercapacitor bank; 40. Power supply terminal; 50. Output switch circuit; 60. First switch circuit; 70. Second switch circuit; 11. Main control module; 12. Input voltage sampling module; 13. Supercapacitor voltage sampling module; 14. Output voltage sampling module; 15. Final output voltage sampling module; 16. Status voltage sampling module.

[0016] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] As the core equipment ensuring the continuous operation or safe shutdown of critical loads during mains power anomalies, the intelligence level of the power restoration logic of uninterruptible power supply (UPS) systems directly affects user experience and system security. In traditional solutions, the triggering mechanism of the "power-on self-start" function in UPS systems has flaws. It relies on the physical process of the supercapacitor, acting as a backup power source, completely depleting its charge, causing the output voltage to drop to a point where it can no longer supply power. When the mains power experiences a brief interruption and then quickly recovers, and the supercapacitor still has residual charge, the triggering condition for "power-on self-start" is not met, and the system cannot actively perform a power restoration operation. It can only rely on manual intervention to restart, limiting the flexibility and automation of system recovery. Furthermore, traditional solutions cannot effectively identify the specific reasons for load shutdown, i.e., they cannot distinguish between a user-initiated active shutdown and a protective shutdown triggered by a mains power anomaly. This leads to the system performing a power-on operation after mains power is restored, which can easily cause unexpected restarts due to mains power fluctuations during user-initiated shutdown maintenance. This not only violates the user's operational intentions but may also cause data conflicts or hardware maintenance security risks. Therefore, there is an urgent need for a power supply control method to improve the lack of flexibility in power-on restart of uninterruptible power supply systems and the safety problems caused by accidental restarts.

[0019] Therefore, refer to Figure 1 This invention proposes a power supply control method applied to an uninterruptible power supply (UPS) system. The UPS system includes a mains input terminal, a supercapacitor bank, an output switching circuit, and a power supply terminal for connecting a load. The mains input terminal is electrically connected to the first input terminal of the output switching circuit via an input power direct path. The input terminal of the supercapacitor bank is electrically connected to the mains input terminal. The output terminal of the supercapacitor bank is electrically connected to the second input terminal of the output switching circuit via a backup power path. The output terminal of the output switching circuit is electrically connected to the power supply terminal. The power supply control method includes: Step S100: Detect the DC input voltage connected to the mains input terminal, and if it is determined that the input voltage is abnormal based on the DC input voltage, shut off the input power direct path, connect the backup power path, control the output switch circuit to be in the conducting state to switch to the supercapacitor group power supply, and send a power failure signal to the load to trigger the load to perform a shutdown action, and send a shutdown confirmation signal.

[0020] In this embodiment, the power supply control method of the present invention can be applied to the control device of an uninterruptible power supply system. The control device can be implemented using a main controller, such as an MCU (Micro Controller Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), a PLC (Programmable Logic Controller), or a SOC (System On Chip).

[0021] In this embodiment, the AC power input terminal is the external DC power input port of the uninterruptible power supply (UPS) system, used to connect an external power adapter or switching power supply, etc. The AC power input terminal can be connected to 12V or 24V voltage, which can be set according to actual needs and is not limited here. The AC power input terminal is the main power input interface of the UPS system. The input power direct path refers to the electrical connection path through which the DC input voltage connected to the AC power input terminal is directly delivered to the output switching circuit. In hardware, it is usually implemented by a "bypass switch circuit" (such as three back-to-back connected P-channel MOSFETs) and power connection lines. When the AC power is normal, the current preferentially flows through this low-impedance path to achieve the highest power supply efficiency. The supercapacitor bank refers to the energy storage unit of the UPS system (used as a backup power source), which can be composed of multiple high-performance supercapacitors connected in series. It is used to provide instantaneous power support when the AC power drops abnormally, ensuring that the load (such as the motherboard) can complete data saving and safe shutdown operations. The backup power path refers to the electrical connection path through which the supercapacitor bank delivers power to the output switching circuit. In terms of hardware, a bidirectional DC-DC converter (boost circuit) is typically included. This path is activated when the mains power fails, converting the low-voltage DC current from the capacitors into the voltage required by the load. The output switch circuit is located at the end of the internal power supply path of the UPS system, serving as the final output disconnect switch, and is implemented using a MOSFET. The output switch circuit is directly connected in series between the internal power supply (mains power or supercapacitor bank) and the external load (motherboard), controlling its on / off state to determine whether the motherboard receives power. The power failure signal is a hardware interrupt signal (such as the AC_FAIL signal) sent by the control device (such as the MCU) to the motherboard. This signal informs the motherboard in advance that "the mains power has been disconnected, and the system is currently powered by the backup power supply," triggering the motherboard operating system to immediately enter the emergency data saving and orderly shutdown process. The shutdown confirmation signal is a level signal (such as a high level) fed back to the UPS by the motherboard through a specific general purpose output pin (GPO) after receiving the power failure signal. Its logical meaning is: "Power failure notification received, emergency shutdown process is currently being executed."

[0022] In this embodiment, the control device may include a voltage sampling circuit and a main controller. The voltage sampling circuit detects the DC input voltage connected to the mains input terminal and outputs it to the main controller. This allows the main controller to immediately shut off the direct input power path and simultaneously activate the backup power path when it detects a voltage drop, ensuring that the supercapacitor bank supplies power to the load via the output switching circuit. Specifically, the main controller sends a power-down signal to the motherboard through a specific GPIO pin. Upon receiving this signal, the operating system executes the emergency shutdown procedure and sets the level of the "General Purpose Output Pin (GPIO)" to the first level (e.g., pull high) at the motherboard firmware level as a shutdown confirmation signal. This achieves seamless switching of the power supply path and notifies the motherboard to enter the "emergency shutdown" process. This ensures that the load (motherboard) remains powered even during a mains power failure, with the supercapacitor bank taking over the power supply.

[0023] Step S200: Detect the load status feedback voltage. If the load has completed the shutdown action based on the status feedback voltage and the shutdown confirmation signal is received, control the output switch circuit to be in the off state so that the load input voltage drops to a preset first voltage value. The status feedback voltage is related to the load's power-on / power-off state.

[0024] In this embodiment, the status feedback voltage is a voltage sampling value used to characterize the current physical operating state of the load (motherboard), such as the "critical power rail" inside the motherboard (e.g., the 3.3V or 5V system main power supply voltage). When the motherboard is working normally, this voltage is high; when the motherboard completes the shutdown action or power-off, this voltage drops to near 0V. The status feedback voltage can be used to determine whether the motherboard has completed the shutdown. A preset first voltage value can be set in advance by the R&D personnel and stored in the memory of the control device. When the main controller detects that the status feedback voltage of the motherboard is close to the preset first voltage value (e.g., 0V), it confirms that the motherboard has completed the shutdown action. Subsequently, the main controller controls the output switch circuit to be in the off state, and the input voltage of the motherboard (i.e., the output voltage of the output switch circuit) begins to drop. When the main controller detects that the input voltage of the motherboard (i.e., the output voltage of the output switch circuit 50) is lower than the preset first voltage value (e.g., 0V), it confirms that the motherboard has been completely powered off (logical power-off state), thereby logically marking a "complete power-off event". Optionally, the power-off can also be confirmed by detecting the input voltage of the load or the voltage at the output of the output switch circuit.

[0025] In this embodiment, the control device can monitor the motherboard's "critical power rail" (e.g., 3.3V or 5V) in real time. When the voltage drops to near a preset first voltage value (e.g., 0V), it indicates that the motherboard has shut down. The control device detects that the motherboard's GPO pin is in a first-level state (e.g., the shutdown confirmation signal is high), confirming that the motherboard shut down due to an "abnormal power failure." Only when both of the above conditions are met simultaneously will the control device control the output switching circuit (final output MOSFET) to turn off. Thus, this dual verification of "voltage and signal" solves the problem of system damage caused by "GPO alone not guaranteeing a complete shutdown." Detecting the load's status feedback voltage confirms that the motherboard has truly shut down safely and actively cuts off the power supply to the motherboard, ensuring that the motherboard has completed data saving before the supercapacitor bank's power is depleted. Actively cutting off the output switching circuit causes the motherboard's input voltage to drop to a preset first voltage value (near 0V), solving the problem in traditional solutions where "residual charge in the supercapacitor causes the UPS system to be unable to actively restore power after a brief interruption of mains power and rapid recovery," creating conditions for "power-on restart" after mains power restoration. Thus, after logically marking a "complete power outage event", if the input voltage is restored, the UPS system can perform automatic restart operation according to the preset strategy, without waiting for the supercapacitor bank to run out of energy naturally. This achieves rapid and controllable recovery when the supercapacitor bank still has power, improving the system's response speed and flexibility.

[0026] Step S300: When it is determined that the load has completed the shutdown action based on the state feedback voltage and an active shutdown signal is received from the load, the output switch circuit is controlled to be in the conducting state, and the input power supply direct path is turned on while the backup power supply path is turned off.

[0027] In this embodiment, the active shutdown signal is another state level signal fed back from the motherboard to the UPS system. When the user clicks "Shut Down" or presses the power button in the motherboard operating system, the motherboard will not trigger the abnormal power failure protection process, so the level state of its GPO pin will not change (e.g., it remains in the default low level state). The control device can determine that the current shutdown behavior is "user-initiated" rather than caused by a mains power abnormality by recognizing this "remaining default state" signal. This is suitable for scenarios where the user actively controls the load to shut down via software or buttons, and the mains power may be normal or fluctuating briefly during the shutdown process.

[0028] In this embodiment, the control device determines that the motherboard's "critical power rail" has dropped to near 0V based on the status feedback voltage, confirming that the motherboard has been safely shut down. Simultaneously, it detects that the motherboard's GPO pin remains in a second-level state (e.g., low level / default state). Because this is a user-initiated shutdown, the motherboard does not receive a "power-down signal," so the GPO will not flip. After confirming an active shutdown, the control device does not shut down the output switch circuit but keeps it on, ensuring the mains power direct path is open. At this time, even if the mains power briefly fails and then recovers, because the output switch circuit remains on and the motherboard is already shut down, the motherboard's input voltage is provided by the supercapacitor bank. Therefore, when the mains power is restored, the uninterruptible power supply system will only remain in standby mode and will not trigger automatic startup. Because the user's "active shutdown" is identified, the system's standby / shutdown state must be maintained. This respects the user's operational intent and prevents the system from performing a power-on action to restart during mains power fluctuations or recovery, which could lead to an unexpected restart of the load device after the user's active shutdown, posing a safety hazard.

[0029] In this embodiment, by real-time monitoring of the load's status feedback voltage (critical power rail) and combining it with a shutdown confirmation signal for dual verification, the uninterruptible power supply (UPS) system no longer passively waits for the supercapacitor bank to run out of power. Instead, after confirming that the load (motherboard) has safely completed the shutdown process, it controls the output switching circuit to turn off, forcibly pulling the load voltage down to a preset first voltage value (e.g., 0V). This proactive disconnection mechanism creates a complete "power-down environment," eliminating the interference of residual supercapacitor bank power on system status judgment. When the mains power returns to normal, the UPS system can immediately identify and execute a power-on restart operation without waiting for the capacitors to run out of power, improving the UPS system's recovery flexibility and automation in scenarios with fluctuating mains power.

[0030] In this embodiment, traditional solutions fail to distinguish between "user-initiated shutdown" and "power outage triggering," leading to an automatic power-on upon power restoration and potential safety hazards due to unexpected restarts after user-initiated shutdowns. This invention addresses this issue by sending a power-down signal to the load and receiving a corresponding shutdown confirmation signal (GPO level change), as well as detecting active shutdown signals (GPO level remains at default), achieving accurate identification of the shutdown cause. When the uninterruptible power supply (UPS) system detects an active shutdown signal from the load and the load is already powered off, the control device keeps the output switching circuit on, preventing automatic power-on upon power restoration. This signal feedback-based identification mechanism effectively distinguishes between "abnormal power-down protection" and "user-initiated shutdown" scenarios. In user-initiated shutdown scenarios, even with power fluctuations or restoration, the device remains powered off, avoiding data risks and operational inconveniences caused by unexpected restarts, thus improving the safety and user experience of the UPS system.

[0031] In this embodiment, considering that relying solely on a single signal (such as relying solely on the GPO or solely on monitoring critical power rails) may lead to misjudgments, for example, the GPO may issue a command but the system may freeze without actually shutting down, resulting in premature power loss and data corruption. Therefore, this invention adopts a dual verification mechanism combining status feedback voltage (physical layer) and shutdown confirmation signal (logic layer). Only when both conditions are met—detecting a drop in the motherboard's critical power rail voltage (physical shutdown) and receiving a shutdown confirmation signal (logical confirmation of abnormal shutdown)—is the output switch circuit controlled to shut down. This avoids potential malfunctions caused by relying solely on a single signal, ensuring that the physical connection is not severed until the load has completely completed the data saving and shutdown process, thus improving the data security of the uninterruptible power supply system.

[0032] In practical applications, the introduction of dual judgment logic based on critical power rail monitoring and GPO signal feedback not only proactively executes output switching operations based on the actual operating status of the load, eliminating the limitation of system restart caused by residual supercapacitor charge, and improving the recovery flexibility and automated response capability of the uninterruptible power supply system under mains power fluctuation scenarios; it also accurately identifies user-initiated shutdown and abnormal power outage shutdown situations, and executes differentiated power supply strategies accordingly, effectively reducing the safety risk of unexpected equipment restarts after user-initiated shutdown. Thus, the operational reliability of the uninterruptible power supply system and the user experience are improved.

[0033] In another embodiment, reference Figure 2 After detecting the DC input voltage connected to the mains input terminal, the power supply control method further includes: Step S110: If the DC input voltage is less than or equal to a preset second voltage value, determine that the input voltage is abnormal; Step S120: If the DC input voltage is greater than the preset third voltage value, determine that the input voltage is normal; The preset second voltage value is less than the preset third voltage value.

[0034] In this embodiment, the output voltage of the mains power (or adapter) will decrease under load. If the voltage is too low, it will not only fail to maintain the normal operation of the motherboard under load, but may also cause the motherboard power management chip to enter undervoltage protection and force a reset, resulting in data loss. Therefore, a preset second voltage value is set (for example, for a nominal 12V system, the preset second voltage value can be set to 10.5V or 11V). When the DC input voltage is less than or equal to the preset second voltage value, it indicates that the input voltage has dropped, and it is immediately determined to be an abnormal input voltage. The system then actively switches to supercapacitor power supply and notifies the motherboard to start saving data. During normal fluctuations in the mains power, the voltage may fluctuate slightly. As long as the DC input voltage is greater than a preset third voltage value, the input voltage is considered normal, and the input power direct path remains open. This ensures that the uninterruptible power supply system still enjoys high conversion efficiency when the mains power is normal. At the same time, by introducing a voltage hysteresis mechanism, the problem of false start-up caused by DC input voltage fluctuations is improved, enhancing reliability and stability.

[0035] In one embodiment, after controlling the output switching circuit to be in the off state when the power supply control method further includes: (1) after determining that the load has completed the shutdown action based on the state feedback voltage and receiving the shutdown confirmation signal. If the input voltage is determined to have returned to normal based on the DC input voltage, the output switch circuit is controlled to be in the conducting state, and the input power supply direct path is opened while the backup power supply path is turned off.

[0036] Based on the above embodiments, refer to Figure 7 When the mains power fails, the UPS system receives a shutdown confirmation signal (such as a low-level GPO) from the mainboard. Upon detecting a complete power failure on the mainboard power rail, it immediately or as needed shuts down the final output MOSFET, causing the mainboard input voltage to drop to near 0V, thus logically marking a "complete power failure event". If the input voltage subsequently recovers, the UPS system can automatically restart according to the set strategy, without waiting for the supercapacitor to deplete its energy naturally. Figure 7 The diagram illustrates a typical scenario (the time interval between mains power failure and restoration is greater than 1 second) for a controllable power-on restart after a mains power failure and restoration. After the control output switch circuit is turned off, if the detected DC input voltage is greater than a preset second voltage value, it indicates that the input voltage has returned to normal. At this point, the load needs to be powered by the input power direct path, and the supercapacitor bank needs to be charged by the DC input voltage connected to the mains input terminal. In other words, the control device keeps the output switch circuit in the conducting state, activating the input power direct path and deactivating the backup power path, while simultaneously controlling the supercapacitor bank to charge.

[0037] Similarly, refer to Figure 8When the motherboard is manually shut down by the user, the UPS system will not disconnect the final output MOSFET; that is, the motherboard input remains powered. In this case, the motherboard is still powered by the direct input power path. Even in the event of a mains power failure, the final output MOSFET remains conducting to maintain output, thus preventing a restart. Figure 8 The diagram shows a flowchart illustrating the process of mains power loss and restoration during a single active shutdown. This demonstrates that the UPS system possesses the ability to identify the cause of load shutdown and provide differentiated recovery, thereby ensuring power continuity while maintaining the user's active operation, meeting user needs, and improving safety.

[0038] It should be noted that when the input voltage is abnormal, the UPS system switches to supercapacitor power supply. If the supercapacitor bank runs out of energy or the system performs a protective shutdown, the output voltage of the subsequent stage (the output voltage of the switching circuit) will be shut down, causing a complete power drop to the core of the motherboard. If the input voltage returns to normal at this time, the output voltage of the subsequent stage will be re-established, which is equivalent to the motherboard being powered on again, triggering automatic startup under the default state. However, if the DC input voltage connected to the AC input terminal experiences extremely rapid abnormal fluctuations, the MCU will be in an abnormal metastable power-on state before the MCU's power rail has been stabilized or the internal reset sequence has been completed. Its internal registers and clock may not be correctly initialized to the determined state, resulting in abnormal program operation or system crash, and inability to respond to normal power-on signals.

[0039] In one embodiment, reference Figure 3 After controlling the output switching circuit to be in the off state, the power supply control method further includes: Step S210: Detect the voltage at the output terminal of the output switch circuit to obtain the load power supply voltage; Step S220: When it is determined that the input voltage has returned to normal based on the DC input voltage, and the load power supply voltage has dropped to the preset first voltage value, the duration of the output switch circuit being turned off is controlled to reach the preset delay duration. Step S230: After the duration of the output switch circuit being turned off reaches the preset delay duration, the output switch circuit is controlled to be in the conducting state, and the input power supply direct path is opened, while the backup power supply path is turned off, so that the load can perform a power-on or power-on restart action.

[0040] Wherein, the preset first voltage value is equal to 0.

[0041] Based on the above embodiments, when the load has completed the shutdown action based on the state feedback voltage and a shutdown confirmation signal is received, the control output switching circuit is in the off state. After the MOSFET is turned off, the load supply voltage may not instantly return to zero due to parasitic capacitance or residual charge at the output terminal. Therefore, the control device can output the voltage at the output terminal of the switching circuit in real time. This ensures that the power supply is stable and reliable when power is restored, avoiding forced restarts under low voltage from capacitor supply. If the load supply voltage has returned to zero, it ensures that all capacitors inside the motherboard have been fully discharged. Even if the voltage has returned to zero, a preset delay time (e.g., tens to hundreds of milliseconds) can be waited to provide sufficient power-down reset time for the reset circuit and power management chip on the motherboard, ensuring that their internal timing logic is completely cleared. After confirming the internal reset timing, if the mains power is restored, i.e., the input voltage returns to normal, power is supplied to the motherboard to trigger power-on.

[0042] In this embodiment, after the UPS module is powered on, the input power direct path is established. Simultaneously, the supercapacitor is charged using the DC input voltage, and the output voltage of the supercapacitor bank is detected to confirm that its energy has reached a set threshold, thus ensuring backup power supply capability. When the input voltage abnormally drops, a power supply switch is triggered. Simultaneously, the control device sends a power-down signal to the main board, causing the load to receive the signal and begin shutting down. A shutdown confirmation signal is also sent back. The control device receives a low-level GPO signal (shutdown confirmation signal) from the main board to coordinate the shutdown process. If the input voltage recovers immediately during this process, the UPS system continues to execute the predetermined shutdown operation until the critical power rail of the main board is completely de-energized (based on the status feedback voltage to determine that the load has completed the shutdown action). Subsequently, the UPS system shuts off the final output MOSFET and continuously monitors the voltage at the output terminal of the output switching circuit, i.e., the load supply voltage. Only when the load supply voltage drops to near 0, confirming that the power supply channel to the motherboard has been completely disconnected (indicating that the final output power failure has been completed), does the UPS system re-turn on the final output MOSFET after a preset delay time to power on the motherboard and charge the supercapacitor, thereby achieving stable and reliable automatic restart upon power restoration. Figure 9 The flowchart shown is a controllable power-on automatic restart process under a single rapid power-on and power-off condition.

[0043] The above steps address the problem of motherboards easily falling into metastable states and crashing under rapid fluctuations in mains power. First, a dual verification logic of "status feedback voltage (critical power rail) + GPO signal" is employed to identify the motherboard's shutdown intention and execution progress. This ensures that even under complex conditions of abnormal mains power drops or instantaneous recovery, the system can still execute a protective shutdown according to the predetermined strategy, avoiding unexpected restarts caused by misjudgments. Simultaneously, after confirming the logical shutdown, the output voltage is further monitored until it completely returns to zero, and a preset delay is introduced to force the motherboard's internal capacitors to completely discharge. This provides a sufficient power-down reset window for the power management chip and reset circuit, eliminating interference from residual charge on hardware timing. Finally, only after ensuring the motherboard is in a "cold start" state and the mains power has stably recovered does the UPS system reconnect the power supply path to the output switching circuit. This achieves reliable automatic restart under extreme conditions, improving the collaborative stability and data security of the uninterruptible power supply system and the load equipment.

[0044] In another embodiment, after determining that the load has completed the shutdown action based on the state feedback voltage and receiving an active shutdown signal from the load, the power supply control method further includes: ... ... After controlling the output switching circuit to be in the ON state, and opening the input power supply direct path while shutting off the backup power supply path. If an abnormal input voltage is determined based on the DC input voltage, the input power direct path is shut off, and the backup power path is activated to switch to power supply from the supercapacitor bank.

[0045] Based on the above embodiments, if a user initiates a shutdown when the mains power is normal, the UPS system will control the output switch circuit to be in the conducting state and open the input power direct path. At this time, the motherboard is normally consuming the DC input voltage from the mains power and executing the shutdown procedure. If the mains power suddenly fails during the shutdown procedure, the ongoing shutdown procedure may be forcibly interrupted, leading to data loss or file system corruption. Therefore, in this embodiment, when the control device determines that the input voltage is abnormal, it shuts off the input power direct path and opens the backup power path to switch to supercapacitor bank power supply. This allows the supercapacitor bank to power the load while the motherboard's shutdown process is not yet complete. In this way, the motherboard can use the power of the supercapacitor bank to smoothly and safely complete the remaining shutdown process (such as saving data and uninstalling drivers), preventing unexpected power failures, ensuring the smooth completion of the active shutdown process, and improving data security.

[0046] Understandably, towards the end of the supercapacitor bank's operation, its output voltage continuously decreases. If a comparator with a single threshold is used to control the power supply (i.e., the on-threshold equals the off-threshold, such as 3V), when the voltage drops to the off-threshold, the load power supply is cut off, and the load current will momentarily drop to zero. This rapid change in current generates a high rate of change of current di / dt, which in turn triggers an inductance effect, producing a momentary back electromotive force, causing a brief upward rebound in voltage. When the voltage rebounds to 3.1V, the system mistakenly believes that "the voltage is sufficient" and restarts the power supply; however, the supercapacitor bank is actually de-energized, and the voltage immediately drops back below 3.0V, causing the system to cut off the power supply again. This cycle repeats, trapping the system in a vicious cycle of "cut-off-rebound-restart-cut-off," leading to an unstable oscillation.

[0047] Therefore, in one embodiment, reference is made to Figure 4 During the switch to supercapacitor bank power supply, the power supply control method further includes: Step S400: Detect the output voltage of the supercapacitor bank; Step S500: When it is determined that the output voltage of the supercapacitor bank is less than or equal to the preset shutdown voltage threshold, the backup power supply path is turned off, and the output switch circuit is controlled to be in the off state to cut off the input voltage of the load. Step S600: When the output voltage of the supercapacitor bank is greater than or equal to the preset power-on voltage threshold, the backup power supply path is turned on, and the output switch circuit is controlled to be in the on state to provide input voltage to the load. Wherein, the preset shutdown voltage threshold is less than the preset power-on voltage threshold.

[0048] In this embodiment, because the voltage of the supercapacitor bank decreases during discharge, the control device can sample its terminal voltage in real time using an ADC (analog-to-digital converter) to accurately determine whether the output switching circuit needs to be turned off or on. For example, the control device can compare the real-time acquired output voltage of the supercapacitor bank with a preset shutdown voltage threshold. When the output voltage is less than or equal to the preset shutdown voltage threshold, the backup power supply path and the final output MOSFET are immediately turned off, i.e., the power supply to the load motherboard is cut off. At this time, due to the instantaneous current cut-off, the parasitic inductance in the circuit will generate a voltage rebound (e.g., a momentary jump to 3.1V). Simultaneously, power is only allowed to be turned on again when the output voltage of the supercapacitor bank rises back to the preset power-on voltage threshold, preventing accidental device startup during voltage rebound and avoiding oscillation.

[0049] In this embodiment, the present application can provide a window voltage comparator with hysteresis characteristics. Different preset power-on voltage thresholds and preset power-off voltage thresholds are set through the comparator, ensuring that the preset power-off voltage threshold is less than the preset power-on voltage threshold. Because the preset power-off voltage threshold is less than the preset power-on voltage threshold, even if the voltage rebounds, the system will not restart. Only when the mains power is restored, the supercapacitor bank is recharged, and the voltage truly rises above the preset power-on voltage threshold will it provide backup power to the motherboard. It should be noted that both the preset power-on voltage threshold and the preset power-off voltage threshold can be set by the developers and stored in advance in the memory of the control device. The voltage difference between the preset power-off voltage threshold and the preset power-on voltage threshold must ensure that a voltage rebound will not cause the device to restart.

[0050] By introducing a window voltage comparison mechanism with hysteresis characteristics, an asymmetric power on / off control logic was constructed, improving the system oscillation problem caused by inductive effect at the end of supercapacitor discharge. Specifically, by setting a preset power-on voltage threshold higher than a preset power-off voltage threshold, a safe shielding zone capable of accommodating voltage rebound amplitude is formed on the voltage control curve. When the uninterruptible power supply (UPS) system experiences parasitic inductive voltage rebound due to low-charge-triggered shutdown, the system can accurately identify and shield this false voltage fluctuation because the rebound voltage is still lower than the higher preset power-on voltage threshold, forcing the system to maintain a stable shutdown state. This effectively avoids the device falling into a "cut-off-rebound-restart" vicious cycle. Thus, not only is the data security and hardware protection of the load motherboard ensured under extreme power failure conditions, but the uncertainty of the voltage critical point is also eliminated, improving the control accuracy and operational reliability of the UPS system at the edge of energy depletion.

[0051] In one embodiment, the power supply control method further includes: If the input voltage is determined to be normal based on the DC input voltage, the supercapacitor bank is controlled to charge until the output voltage of the supercapacitor bank reaches the preset upper limit of the charging voltage, at which point the supercapacitor bank is controlled to stop charging.

[0052] In this embodiment, reference Figure 7 , Figure 8 and Figure 9The control device continuously monitors the DC input voltage connected to the mains input terminal. When it confirms that the DC input voltage is greater than a preset second voltage value (i.e., the mains power is normal), the control device activates the charging circuit (e.g., turning on the charging MOSFET or controlling the bidirectional DC-DC converter to be in charging mode), inputting the energy from the mains power into the supercapacitor bank. When the mains power is normal, the supercapacitor bank is charged. This ensures that if the mains power experiences an abnormal drop, the supercapacitor bank has sufficient energy to support the motherboard in an emergency shutdown. Considering that if the output voltage of the supercapacitor bank exceeds its rated withstand voltage limit, it could lead to internal electrolyte decomposition, gas production, or even an explosion, the charging current must be precisely cut off when the safety limit is reached. During charging, the control device continuously samples the terminal voltage of the supercapacitor bank through its internal voltage detection circuit. When it detects that the output voltage of the supercapacitor bank is ≥ the preset charging voltage limit (e.g., for a nominal 3V capacitor, the preset charging voltage limit might be set to 2.65V or 2.7V), the control device immediately shuts off the corresponding charging circuit, stopping the charging of the supercapacitor bank. The preset charging voltage limit is pre-set by the R&D personnel and stored in the control device's memory. In this way, the UPS system is guaranteed to have backup power supply capability. By controlling the upper limit of voltage, the service life of the supercapacitor is extended, ensuring the long-term safety and reliability of the uninterruptible power supply system.

[0053] This application also proposes an uninterruptible power supply system, referenced... Figure 5 The uninterruptible power supply system includes: Control device 10, the control device 10 being used to execute the power supply control method described in any of the above claims; AC power input terminal 20; The supercapacitor bank 30 is composed of multiple supercapacitors connected in series, and the input terminal of the supercapacitor bank 30 is electrically connected to the mains input terminal 20. Power supply terminal 40 is used to connect the load; An output switch circuit 50 is provided, wherein the controlled terminal of the output switch circuit 50 is electrically connected to the control device 10, and the output terminal of the output switch circuit 50 is electrically connected to the power supply terminal 40. A first switching circuit 60, the first end of which is electrically connected to the mains input terminal 20, the second end of which is electrically connected to the first input terminal of the output switching circuit 50, and the controlled terminal of the first switching circuit 60 is electrically connected to the control device 10. The mains input terminal 20, the first switching circuit 60, and the first input terminal constitute a direct input power path. The second switching circuit 70 has a first terminal electrically connected to the output terminal of the supercapacitor group 30, a second terminal electrically connected to the second input terminal of the output switching circuit 50, and a controlled terminal electrically connected to the control device 10. The output terminal of the supercapacitor group 30, the second switching circuit 70, and the second input terminal constitute a backup power supply path. The control device 10 is used to control the first switching circuit 60 to be in the on state so as to conduct the input power direct path, and to control the second switching circuit 70 to be in the off state so as to turn off the backup power path. Alternatively, it can be used to control the second switching circuit 70 to be in a conducting state to enable the backup power supply path, and to control the first switching circuit 60 to be in a turning-off state to disable the input power supply direct path.

[0054] In this embodiment, the control device 10 can be implemented using the aforementioned main controller; the output switch circuit 50, the first switch circuit 60, and the second switch circuit 70 can all be implemented using switching transistors such as MOSFETs and IGBTs.

[0055] In this embodiment, the mains input terminal 20 is used to receive DC power from the external power grid or power adapter. It simultaneously performs two tasks: directly powering the motherboard load and, when the mains power is normal, acting as a charging power source to replenish the supercapacitor bank 30. The supercapacitor bank 30 consists of multiple supercapacitors connected in series to improve the overall voltage withstand value. The supercapacitor bank 30 also includes a buck-boost module to convert the output voltage of the supercapacitor bank 30 into the input voltage required by the load. When the mains power is normal, it absorbs and stores electrical energy; when the mains power drops abnormally, it releases the stored DC energy to provide backup power for the load to maintain shutdown. The power supply terminal 40 is used to connect to an external load (such as the motherboard), and the quality of its output voltage directly determines whether the load can operate normally. The output switching circuit 50 (i.e., the final output MOSFET described in the above embodiment) is located at the end of the power supply path, directly connected in series between the internal power supply and the power supply terminal 40. When the output switching circuit 50 is on, it allows the internal power supply (whether mains power or supercapacitor bank 30) to flow to the load; when it is off, it completely cuts off the power supply to the load, causing the load voltage to return to zero. The first switching circuit 60 is connected in series between the mains input terminal 20 and the output switching circuit 50. When the first switching circuit 60 is on, the mains power is directly supplied to the load at its highest efficiency (the system efficiency is highest at this time). When off, it blocks the mains power to prevent mains power fluctuations from impacting the load, or to achieve physical isolation when the system needs to switch to power supply from the supercapacitor bank 30. The second switching circuit 70 is connected in series between the supercapacitor bank 30 and the output switching circuit 50. When the second switching circuit 70 is on, it releases the electrical energy of the supercapacitor bank 30 to the load; when off, it disconnects the connection between the supercapacitor bank 30 and the load when the supercapacitor bank 30 is depleted or when the uninterruptible power supply system needs to be completely powered off, preventing interference from residual charge.

[0056] By controlling the first switching circuit 60 and the second switching circuit 70 respectively, the mutual exclusion of the input power direct path and the backup power path is achieved (i.e., when one is on, the other must be off), avoiding current backflow or short-circuit conflicts between the mains power and the capacitor internally, and ensuring the safety and stability of energy flow within the system. Simultaneously, by using the output switching circuit 50 as the final control node of the power supply path, the control device 10 can independently control the power supply status of the load, regardless of the selection of the front-end path, thus providing a reliable hardware foundation for the system to execute control strategies such as active disconnection, complete power failure, and intelligent delayed restart.

[0057] Alternatively, in another embodiment, reference is made to... Figure 6 The control device 10 includes: The main control module 11 is electrically connected to the first switch circuit 60, the second switch circuit 70, and the output switch circuit 50, respectively. The input voltage sampling module 12 is used to detect the DC input voltage connected to the mains input terminal 20 and output a first voltage signal to the main control module 11 so that the main control module 11 can determine the magnitude of the DC input voltage based on the first voltage signal. The supercapacitor voltage sampling module 13 is used to detect the voltage across the supercapacitor bank 30 and output a second voltage signal to the main control module 11, so that the main control module 11 can determine the output voltage of the supercapacitor bank 30 based on the second voltage signal. The output voltage sampling module 14 is used to collect the voltage connected to the first input terminal or the second input terminal of the output switch circuit 50 and output it to the main control module 11. The final output voltage sampling module 15 is used to collect the voltage at the output terminal of the output switch circuit 50 and output a third voltage signal to the main control module 11 so that the main control module 11 can determine the load supply voltage based on the third voltage signal. The status voltage sampling module 16 is used to detect the critical power rail voltage of the load and output a fourth voltage signal to the main control module 11 so that the main control module 11 can determine the status feedback voltage of the load based on the fourth voltage signal.

[0058] In this embodiment, the input voltage sampling module 12 is used to collect the DC input voltage in real time. When the DC input voltage is not greater than a preset second voltage value, an AC_FAIL signal (power failure signal) is generated. This signal not only triggers the internal switching of the UPS system, but also sends it to the main board, notifying it to immediately save the data and start the emergency shutdown process. The supercapacitor voltage sampling module 13 is used to collect the voltage across the supercapacitor bank 30, that is, the output voltage of the supercapacitor bank 30. This is used by the main control module 11 to determine the energy storage status of the supercapacitor. Only when the output voltage reaches the preset start-up voltage threshold is the start-up or the output voltage maintained to provide backup power to the load. If the supercapacitor bank 30 is low on power, the second switching circuit needs to be turned off to disconnect the backup power path. This improves the problem of accidental start-up when the backup energy is insufficient. The output voltage sampling module 14 is used to collect the direct output voltage of the supercapacitor bank 30 or the bypass path (input power direct path) (that is, the voltage connected to the first or second input terminal of the output switching circuit 50). When the voltage connected to the second input terminal drops to the preset shutdown voltage threshold due to insufficient energy in the supercapacitor bank 30, the final output voltage and the shutdown of the output voltage are triggered. The final output voltage sampling module 15 is used to collect the final voltage actually supplied to the motherboard by the uninterruptible power supply system (i.e., the voltage at the output terminal of the output switching circuit 50) so that the main control module 11 can determine the load supply voltage. After the uninterruptible power supply system decides to shut down the output, it must continuously detect the load supply voltage and wait for the load supply voltage to drop below a very low threshold (a preset first voltage value, such as 0V) before the main control module 11 allows the response to the turn-on command again. In this way, the problem of "motherboard only shutting down and not restarting" or misjudging the status caused by the incomplete discharge of the output voltage in the scenario of rapid switching of DC input voltage is effectively solved. The status voltage sampling module 16 is used to collect the critical power rail of the motherboard (represented as status feedback voltage) and the dedicated GPO signal (shutdown confirmation signal to confirm whether the motherboard is actively shutting down or abnormally shutting down). The main control module 11 monitors whether the critical power rail of the motherboard exists and receives the GPO signal sent by the motherboard. When the motherboard receives the AC_FAIL signal and starts executing the shutdown procedure, it can actively notify the UPS system that it has entered the shutdown process by pulling the preset GPO signal line low, thereby realizing a hardware and software coordinated shutdown sequence.

[0059] By constructing a multi-dimensional sampling feedback closed loop that includes DC input voltage, supercapacitor output voltage, direct output voltage, final output voltage, and load status, combined with the physical isolation mechanism of the output switching circuit 50, the defects of power supply status misjudgment caused by rapid switching of mains power or residual charge in traditional solutions can be improved. This ensures that the uninterruptible power supply system can accurately identify and execute preset power strategies after experiencing mains power fluctuations of any interval and any mode. For example, in the "power-on automatic" mode, it can reliably trigger the automatic power-on sequence; while in the "power-off automatic" mode, it can forcibly maintain the shutdown state, thereby preventing accidental restarts or state drift and improving the operational reliability of the uninterruptible power supply system.

[0060] It is worth noting that since the uninterruptible power supply system of the present invention is based on the power supply control method described above, the embodiments of the uninterruptible power supply system of the present invention include all the technical solutions of all embodiments of the power supply control method described above, and the technical effects achieved are exactly the same, so they will not be repeated here.

[0061] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A power supply control method, characterized in that, This invention is applied to an uninterruptible power supply (UPS) system, which includes an AC power input terminal, a supercapacitor bank, an output switching circuit, and a power supply terminal for connecting a load. The AC power input terminal is electrically connected to the first input terminal of the output switching circuit via an input power direct path. The input terminal of the supercapacitor bank is electrically connected to the AC power input terminal. The output terminal of the supercapacitor bank is electrically connected to the second input terminal of the output switching circuit via a backup power path. The output terminal of the output switching circuit is electrically connected to the power supply terminal. The power supply control method includes: The system detects the DC input voltage connected to the mains input terminal, and if it determines that the input voltage is abnormal based on the DC input voltage, it shuts off the input power direct path, connects the backup power path, controls the output switching circuit to be in the conducting state to switch to the supercapacitor bank power supply, and sends a power failure signal to the load to trigger the load to perform a shutdown action, and sends a shutdown confirmation signal. The load status feedback voltage is detected. If it is determined based on the status feedback voltage that the load has completed the shutdown action and the shutdown confirmation signal is received, the output switch circuit is controlled to be in the off state so that the input voltage of the load drops to a preset first voltage value. The status feedback voltage is related to the load's power-on / power-off state. When the load has completed the shutdown action based on the state feedback voltage and an active shutdown signal is received from the load, the output switch circuit is controlled to be in the on state, and the input power direct path is turned on while the backup power path is turned off.

2. The power supply control method as described in claim 1, characterized in that, After detecting the DC input voltage connected to the AC mains input terminal, the power supply control method further includes: If the DC input voltage is less than or equal to a preset second voltage value, an input voltage anomaly is determined. If the DC input voltage is greater than a preset third voltage value, the input voltage is determined to be normal. The preset second voltage value is less than the preset third voltage value.

3. The power supply control method as described in claim 1, characterized in that, After determining that the load has completed the shutdown action based on the state feedback voltage and receiving the shutdown confirmation signal, and controlling the output switching circuit to be in the off state, the power supply control method further includes: If the input voltage is determined to have returned to normal based on the DC input voltage, the output switch circuit is controlled to be in the conducting state, and the input power supply direct path is opened while the backup power supply path is turned off.

4. The power supply control method as described in claim 1, characterized in that, After controlling the output switching circuit to be in the off state, the power supply control method further includes: The voltage at the output terminal of the output switch circuit is detected to obtain the load supply voltage; If, based on the DC input voltage, it is determined that the input voltage has returned to normal, and it is determined that the load power supply voltage has dropped to the preset first voltage value, the duration for which the output switch circuit is turned off is controlled to reach the preset delay duration. After the output switch circuit is turned off for a preset delay period, the output switch circuit is turned on and the input power supply direct path is opened, while the backup power supply path is turned off, so that the load can perform a power-on or power-restart action.

5. The power supply control method as described in claim 4, characterized in that, The preset first voltage value is equal to 0.

6. The power supply control method as described in claim 1, characterized in that, After determining that the load has completed the shutdown action based on the state feedback voltage and receiving an active shutdown signal from the load, the power supply control method further includes controlling the output switching circuit to be in the ON state, opening the input power supply direct path, and shutting off the backup power supply path, when the load has completed the shutdown action based on the state feedback voltage. If an abnormal input voltage is determined based on the DC input voltage, the input power direct path is shut off, and the backup power path is activated to switch to power supply from the supercapacitor bank.

7. The power supply control method according to any one of claims 1 to 6, characterized in that, During the switch to supercapacitor bank power supply, the power supply control method further includes: Detect the output voltage of the supercapacitor bank; If the output voltage of the supercapacitor bank is determined to be less than or equal to a preset shutdown voltage threshold, the backup power supply path is shut off, and the output switching circuit is controlled to be in the off state to cut off the input voltage of the load. When the output voltage of the supercapacitor bank is greater than or equal to the preset power-on voltage threshold, the backup power supply path is turned on, and the output switching circuit is controlled to be in the on state to provide input voltage to the load. Wherein, the preset shutdown voltage threshold is less than the preset power-on voltage threshold.

8. The power supply control method according to any one of claims 1 to 6, characterized in that, The power supply control method further includes: If the input voltage is determined to be normal based on the DC input voltage, the supercapacitor bank is controlled to charge until the output voltage of the supercapacitor bank reaches the preset upper limit of the charging voltage, at which point the supercapacitor bank is controlled to stop charging.

9. An uninterruptible power supply system, characterized in that, The uninterruptible power supply system includes: A control device, the control device being used to perform the power supply control method as described in any one of claims 1 to 8; AC power input terminal; A supercapacitor bank is composed of multiple supercapacitors connected in series, and the input terminal of the supercapacitor bank is electrically connected to the mains power input terminal. The power supply end is used to connect the load; An output switch circuit, wherein the controlled terminal of the output switch circuit is electrically connected to the control device, and the output terminal of the output switch circuit is electrically connected to the power supply terminal; A first switching circuit, wherein a first terminal of the first switching circuit is electrically connected to the mains input terminal, a second terminal of the first switching circuit is electrically connected to the first input terminal of the output switching circuit, and a controlled terminal of the first switching circuit is electrically connected to the control device, wherein the mains input terminal, the first switching circuit, and the first input terminal constitute a direct input power supply path; The second switching circuit has a first terminal electrically connected to the output terminal of the supercapacitor bank, a second terminal electrically connected to the second input terminal of the output switching circuit, and a controlled terminal electrically connected to the control device. The output terminal of the supercapacitor bank, the second switching circuit, and the second input terminal constitute a backup power supply path. The control device is used to control the first switching circuit to be in the on state so as to conduct the input power direct path, and to control the second switching circuit to be in the off state so as to shut off the backup power path. Alternatively, it can be used to control the second switching circuit to be in a conducting state to enable the backup power supply path, and to control the first switching circuit to be in a turning-off state to disable the input power supply direct path.

10. The uninterruptible power supply system as described in claim 9, characterized in that, The control device includes: The main control module is electrically connected to the first switch circuit, the second switch circuit, and the output switch circuit, respectively. An input voltage sampling module is used to detect the DC input voltage connected to the mains input terminal and output a first voltage signal to the main control module, so that the main control module can determine the magnitude of the DC input voltage based on the first voltage signal. A supercapacitor voltage sampling module is used to detect the voltage across the supercapacitor bank and output a second voltage signal to the main control module, so that the main control module can determine the output voltage of the supercapacitor bank based on the second voltage signal. The output voltage sampling module is used to collect the voltage connected to the first input terminal or the second input terminal of the output switching circuit and output it to the main control module. The final output voltage sampling module is used to collect the voltage at the output terminal of the output switching circuit and output a third voltage signal to the main control module so that the main control module can determine the load supply voltage based on the third voltage signal. The status voltage sampling module is used to detect the critical power rail voltage of the load and output a fourth voltage signal to the main control module so that the main control module can determine the status feedback voltage of the load based on the fourth voltage signal.

Images