A circuit and method of operation for an energy storage capacitor module for a fuse link device protection device

Abstract

The application discloses a circuit and working method for energy storage capacitor module of fuse fault device fuse device, and belongs to the technical field of communication power supply. The application provides a pluggable capacitor module. The module is consistent in shape with a standard rectifier and can be directly inserted into a system idle slot. The module internally comprises a large-capacity capacitor group, a charging management unit, a rapid discharge unit and an intelligent control unit. In normal times, the module is automatically charged for standby; when bus voltage drops due to rectifier short circuit, the intelligent control unit triggers rapid discharge within hundreds of microseconds, so that the capacitor group injects instantaneous large current to melt the fuse of the fault rectifier, thereby realizing physical isolation. The application further expands intelligent functions such as energy grading fusing, cooperative communication with lithium battery BMS and failure self-diagnosis. The application is low in cost, ready to use and maintenance-free, and can effectively prevent base station faults caused by single-point short circuit.

Description

Technical Field

[0001] This invention relates to the field of communication power supply technology, specifically to the circuit and operating method of an energy storage capacitor module for a fuse protection device for a fused device. Background Technology

[0002] Communication base stations widely use communication switching power supply systems, whose basic architecture includes an AC power distribution unit, a rectifier unit, a DC power distribution unit, and a control unit. The core function of the rectifier unit is to convert 220V AC power into a stable 48V DC power to supply power to the downstream communication loads and charge the energy storage battery. To improve system power capacity and reliability, the rectifier unit is typically composed of multiple rectifier modules connected in parallel.

[0003] In actual operation, rectifiers are components with a high failure rate in switching power supply systems. When the power devices inside the rectifier (such as MOSFETs or IGBTs) break down and fail, there is a high probability that the positive and negative terminals of its output will be in a direct short-circuit state. If this short-circuit state lasts for more than 10 milliseconds, it will cause the voltage of the entire 48V power supply bus to collapse, the system to shut down, and trigger a large-scale outage of communication base stations.

[0004] Prior to 2015, communication base stations commonly used 48V lead-acid batteries as energy storage units. When a rectifier experiences an output short circuit, the lead-acid battery can inject a large amount of energy into the fault point in a very short time (usually less than 1 millisecond) through the DC power distribution unit, quickly blowing the fuse inside the rectifier and physically isolating it from the system. During this process, due to the powerful energy support of the lead-acid battery, the system bus voltage can still be maintained above 40V, ensuring that the downstream communication load is not interrupted.

[0005] However, with the evolution of communication technology and the increasing demands for energy density, after 2015, lithium batteries, with their advantages of high energy density and long cycle life, gradually replaced lead-acid batteries as the mainstream energy storage device. But there is a key difference between lithium batteries and lead-acid batteries: lithium batteries integrate a Battery Management System (BMS). One of the core functions of the BMS is short-circuit protection. When a short-circuit current is detected at the external output terminal, the BMS will quickly shut off the battery's output MOSFET within a very short time (typically 500 microseconds) to protect the cell from damage caused by a large current surge.

[0006] This characteristic introduces a new technical challenge: when a short-circuit fault occurs at the rectifier output, the lithium battery's BMS will shut down the output within 500 microseconds, while the fuse inside the faulty rectifier has not yet blown (a fuse requires milliseconds of heat accumulation time to blow). After the lithium battery shuts down, the short-circuit point still exists, but the system has lost power support from the battery. Although the remaining normally functioning rectifiers also have output capability, their internal short-circuit protection mechanisms will also respond quickly and shut down the output. Ultimately, all power sources are protected and shut down, but the short-circuit fault point still exists, causing the entire switching power supply system to shut down protectively, and communication power supply is completely interrupted.

[0007] The pain points currently facing the industry include: 1. Faults cannot be avoided: Short circuits in the power devices inside the rectifier are an inherent failure mode of semiconductor devices and cannot be completely eliminated.

[0008] 2. Irreversible technological iteration: Lithium batteries replacing lead-acid batteries is a technological trend in the field of communication energy, and it is impossible to go back to using lead-acid batteries.

[0009] 3. Restricted use of mixed batteries: Lithium batteries and lead-acid batteries cannot be directly mixed in the same switching power supply system due to their huge differences in charging and discharging characteristics. It is impossible to melt the short circuit point with a small number of lead-acid batteries.

[0010] Currently, the industry lacks effective solutions to the aforementioned problems. Some attempts include increasing the rated current of the fuses inside the rectifier to delay the melting time, but this reduces the normal overload protection capability; or modifying the short-circuit protection delay threshold of the lithium battery BMS, but this would seriously threaten the safety of the lithium battery itself and is not permitted. Therefore, there is an urgent need for a low-cost, highly reliable, plug-and-play, and maintenance-free technical solution to address this technical challenge. Summary of the Invention

[0011] This invention aims to overcome the shortcomings of the prior art by providing a circuit and operating method for an energy storage capacitor module used in a fuse-based protection device for faulty devices. This system utilizes the physical characteristic of a large-capacity capacitor bank capable of releasing a huge pulse current within microseconds. When a rectifier experiences an output short-circuit fault, it provides sufficient energy to fuse the internal fuse of the faulty rectifier, thereby physically isolating the faulty module from the system and ensuring the continuous normal operation of the entire switching power supply system and downstream communication loads.

[0012] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a circuit for an energy storage capacitor module for a fuse-based protection device, applied in a communication switching power supply system with multiple rectifier slots, the system comprising: At least one pluggable capacitor module, the capacitor module having the same external dimensions as the standard rectifier module of the switching power supply system, is used to be plugged into an empty rectifier slot of the switching power supply system. The capacitor module internally includes: Large-capacity capacitor bank: It consists of multiple aluminum electrolytic capacitors connected in parallel or series-parallel, with a total capacity between 50,000 microfarads and 500,000 microfarads. It is used to store the electrical energy required to blow the internal fuse when a short-circuit fault occurs in the rectifier. Charging management unit: connected between the DC bus of the switching power supply system and the large-capacity capacitor bank, used to control the charging process of the capacitor bank, including at least one current-limiting charging resistor and a controllable charging switch. Fast discharge unit: connected between the large-capacity capacitor bank and the DC bus, used to provide a low-impedance discharge path when a rectifier short-circuit fault is detected. The fast discharge unit includes at least one high-power unidirectional conducting device (such as a diode) or a controllable electronic switch (such as a MOSFET or IGBT). Intelligent control unit: includes a microcontroller and a bus voltage sampling circuit, used to monitor system status and control charging and discharging logic.

[0013] Furthermore, the intelligent control unit is also configured to perform intelligent access and pre-charge management: After the capacitor module is inserted into an empty slot, the microcontroller first detects the voltage of the DC bus through the bus voltage sampling circuit. If the bus voltage is within the normal operating range (e.g., 40V~58V), the microcontroller controls the controllable charging switch to charge the large-capacity capacitor bank according to a preset charging curve (constant current first, then constant voltage), so that it reaches a voltage value that is basically equal to the bus voltage within a preset time (e.g., 30 seconds to 5 minutes). If the bus voltage is lower than the preset low voltage threshold (e.g., 30V), the microcontroller determines that there is a short circuit fault in the system, prohibits charging, and issues an alarm signal through the indicator light.

[0014] Furthermore, the intelligent control unit is also configured to perform voltage drop triggering and rapid discharge: When the capacitor bank is in a fully charged standby state, the microcontroller continuously monitors the bus voltage at microsecond intervals (e.g., every 50 microseconds); When the bus voltage drops more than the preset voltage drop threshold (e.g., from 53V to below 38V) within a very short time (e.g., within 100 microseconds), the microcontroller immediately determines it as a rectifier short circuit fault event. At this time, the microcontroller controls the controllable electronic switch in the fast discharge unit to be fully turned on, or keeps the diode in the path, so that the large-capacity capacitor bank injects a large instantaneous current into the DC bus through the fast discharge unit. This current flows into the faulty rectifier module and blows the fuse inside it. The entire response time from voltage drop detection to discharge current output is controlled within 200 microseconds, far less than the 500 microsecond protection action time of the lithium battery BMS. Even though the response time is less than the BMS protection action time, a delayed protection request signal still needs to be sent to ensure the reliability of the fuse trip.

[0015] Furthermore, the large-capacity capacitor bank is divided into multiple independently controllable sub-capacitor banks, each sub-capacitor bank being connected to the fast discharge unit via an independent sub-discharge switch; the intelligent control unit is also configured to execute energy grading and selective fuse mechanisms. When a rectifier short-circuit fault is triggered, the microcontroller first closes only the sub-discharge switch of the first sub-capacitor group with the least energy, releasing a tentative energy pulse; By detecting the rate of change of current and the amount of change of voltage in the short-circuit loop under the exploratory energy pulse, the microcontroller calculates or estimates by looking up a table the minimum fusing energy required to blow the fuse inside the currently faulty rectifier. Based on the estimation results, the microcontroller selectively closes the sub-discharge switches of one or more other electronic capacitor banks, providing just enough total energy to precisely blow the fuse and avoid excessive energy causing unnecessary electrical stress on the system.

[0016] Furthermore, the capacitor module also includes a communication unit, which is connected to the intelligent control unit and is used to interact with the lithium battery BMS in the switching power supply system. The intelligent control unit is configured to execute a cooperative protection protocol: At the moment a rectifier short-circuit fault is detected and a discharge is initiated, the microcontroller sends a short pulse signal to the lithium battery BMS via the communication unit, indicating that an emergency fuse is being executed and protection should be delayed. After receiving the signal, the lithium battery BMS temporarily extends its short-circuit protection response time from the default value (e.g., 500 microseconds) to a preset cooperative time window (e.g., 2 milliseconds). After the capacitor module completes the discharge and fuse operation, the microcontroller sends a signal to the lithium battery BMS via the communication unit, indicating that the fuse process has ended and requesting the restoration of normal protection. The BMS then restores its original short-circuit protection parameters.

[0017] Furthermore, the intelligent control unit is also configured to perform failure prediction and self-diagnosis functions: When the switching power supply system is under light load or idle period (e.g., early morning every day), the microcontroller controls the controllable charging switch to disconnect, isolating the large-capacity capacitor bank from the bus. Then, the capacitor bank is briefly discharged through a known resistor, and the voltage-time curve during the discharge process is collected in real time through the capacitor bank voltage sampling circuit. The microcontroller calculates the current actual capacity C_actual and equivalent series resistance ESR_actual of the capacitor bank based on the collected voltage drop data. Compare C_actual and ESR_actual with the factory default values: If the capacity decay exceeds the first threshold (e.g., 20%) or the ESR increases beyond the first threshold (e.g., 100%), it is determined to be in a sub-healthy state, and an early warning signal is issued through the indicator light or communication unit. If the capacity decay exceeds the second threshold (e.g., 50%), it is determined to be in a failure state, the fast discharge unit is automatically locked, and the failure and unavailability status is reported through the communication unit.

[0018] The system also includes a communication switching power supply protection method based on a capacitor module, comprising the following steps: S1: Insert at least one capacitor module with the same shape as a standard rectifier into an unused rectifier slot in the communication switching power supply system. S2: The intelligent control unit detects the DC bus voltage. If the voltage is normal, it starts the charging management unit to charge the internal large-capacity capacitor bank, so that the capacitor bank reaches the standby state. S3: In standby mode, the intelligent control unit continuously monitors the bus voltage at a high-frequency sampling rate; S4: When a rectifier module experiences a short circuit fault at its output terminal, the bus voltage drops within a very short time. S5: The intelligent control unit detects that the voltage drop exceeds the preset threshold and triggers the rapid discharge unit within 200 microseconds; S6: The large-capacity capacitor bank injects a large instantaneous current into the DC bus through the fast discharge unit. This current flows through the fuse inside the faulty rectifier, causing the fuse to blow within milliseconds, thus physically isolating the faulty rectifier from the system. S7: After the faulty rectifier is isolated, the bus voltage returns to normal, and the capacitor module is recharged under the management of the intelligent control unit, returning to standby status.

[0019] The beneficial effects of the above-described technical solution of the present invention are as follows: 1. This invention addresses the technical challenge of effectively isolating rectifier short circuits in communication switching power supply systems when lithium batteries replace lead-acid batteries. It proposes a protection scheme based on pluggable capacitor modules. The capacitor modules are identical in appearance to standard rectifiers and can be directly inserted into available system slots without any hardware modifications or parameter settings, achieving true plug-and-play and maintenance-free operation. Utilizing the physical characteristic of capacitor banks releasing large currents within microseconds, this invention can trigger rapid discharge within 200 microseconds after a bus voltage drop, far faster than the 500 microsecond protection action time of a lithium battery BMS. This ensures that the fuse inside the faulty rectifier reliably blows before the battery is turned off, thus physically isolating the short circuit point and preventing the entire switching power supply system from crashing. This invention has extremely low cost, near-zero standby power consumption, and long capacitor lifespan and strong environmental adaptability, effectively solving the significant hidden danger of base station communication failures caused by short circuits in a single rectifier.

[0020] 2. This invention further introduces advanced functions such as an intelligent control unit, energy tiered release, collaborative communication with the lithium battery BMS, and self-diagnosis of failures, significantly improving the system's intelligence and reliability. The energy tiered fuse mechanism accurately estimates the minimum fusing energy of the faulty fuse through trial pulses, achieving precise handling and avoiding unnecessary electrical stress impacts on the system caused by excessive energy. Through a collaborative protection protocol with the lithium battery BMS, the capacitor module can request temporary delayed short-circuit protection from the BMS before discharge, transforming the potential competitive relationship between the two into a cooperative one, greatly improving the fuse success rate. In addition, the module's built-in self-diagnostic function can periodically detect the actual capacity and equivalent series resistance of the capacitor bank, issuing warnings or automatically locking before performance deteriorates to failure, truly achieving known status and on-demand maintenance. This invention elevates a simple energy storage device into a high-end protection system integrating intelligent sensing, precise control, and system collaboration. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the internal circuit structure of the capacitor module in Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the system in Embodiment 1 of the present invention, in which the capacitor module is inserted into the switching power supply system and forms a discharge circuit with the faulty rectifier.

[0023] Figure 3 This is a schematic diagram of the internal structure and energy level control of the capacitor module in Embodiment 2 of the present invention.

[0024] Figure 4 This is a flowchart illustrating the communication and collaboration process between the capacitor module and the lithium battery BMS in Embodiment 3 of the present invention.

[0025] Figure 5 This is a schematic diagram of the process of capacitor module performing failure self-diagnosis in Embodiment 4 of the present invention.

[0026] Figure 6 This is a flowchart of the control logic for the overall protection method of the present invention. Detailed Implementation

[0027] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0028] Example 1: Basic Capacitor Module Protection System This embodiment provides a basic circuit for an energy storage capacitor module used in a fuse protection device for a fused device.

[0029] like Figure 1 The diagram shows the internal circuit structure of the capacitor module. The external design of the capacitor module is consistent with that of a standard rectifier in a switching power supply system. It includes a housing identical to the standard rectifier module in a communication switching power supply system, with DC bus positive and negative terminals for electrical connection to the backplane slot of the switching power supply system.

[0030] The interior of the casing mainly contains a large-capacity capacitor bank, a charging management unit, and a fast discharge unit.

[0031] The large-capacity capacitor bank consists of 13 aluminum electrolytic capacitors of 10,000 microfarads connected in parallel, with a total capacity of 130,000 microfarads. Once fully charged, this capacitor bank can store enough energy to release a pulse current of several thousand amperes in a short time.

[0032] The charging management unit consists of a current-limiting charging resistor R1. When the capacitor module is inserted into the system, the bus voltage charges the capacitor bank through resistor R1. Due to the current-limiting effect of resistor R1, instantaneous large currents are prevented from causing surges and arcing on the system bus and connectors. The voltage of the capacitor bank gradually rises from 0V to complete the charging process.

[0033] The rapid discharge unit consists of a high-power Schottky diode D1. The anode of diode D1 is connected to the positive terminal of the capacitor bank, and the cathode is connected to the positive terminal of the DC bus. Under normal conditions, the voltage across the capacitor bank is equal to the bus voltage, and the voltage across diode D1 is zero, indicating it is in the off state, and the capacitor bank does not discharge externally. When the bus voltage suddenly drops due to a fault, the voltage across the capacitor bank becomes higher than the bus voltage, and diode D1 instantaneously conducts in the forward direction, forming a discharge circuit with extremely low impedance.

[0034] The charging process is as follows: Due to the unidirectional conductivity of diode D1, the charging current can only flow to the capacitor through the current-limiting resistor R1. Resistor R1 acts as a buffer to prevent excessive current in the capacitor module during the initial charging stage and to avoid arcing when the capacitor module comes into contact with the power system. The direction of the charging current is shown in the diagram. Figure 1 The arrow points from the center to the left.

[0035] The discharge process is as follows: When discharge is required, the energy of all capacitors is concentrated and discharged rapidly through diode D1. The direction of the discharge current is shown in the diagram. Figure 1 The arrow indicates the flow from the center to the right.

[0036] like Figure 2 The diagram shown illustrates the overall application principle of this system in a switching power supply system. The switching power supply system has multiple rectifier slots, typically 6 to 12, all with redundant configurations. Some slots will be empty without rectifiers; only a capacitor module needs to be inserted into these empty slots. When the capacitor module is inserted into the switching power supply slot, an external 48V voltage slowly charges the 13 capacitors through resistor R1, taking approximately 5 minutes to fully charge. After fully charging, if no rectifier experiences a short circuit, the capacitor module will remain in a fully charged standby state.

[0037] When a power transistor breaks down inside the rectifier module, creating a short circuit, the positive and negative buses of the entire system are instantaneously connected through this short circuit point, causing a sharp drop in bus voltage. At this time, the capacitor bank voltage in the capacitor module is higher than the bus voltage, and diode D1 immediately conducts. Combined with... Figure 1 , Figure 2 ,by Figure 2 Taking rectifier ① as an example, the energy stored in the capacitor bank is released through the following circuit: capacitor bank positive terminal → diode D1 (from positive to negative terminal) → DC bus positive terminal → external bus positive terminal → positive terminal of the faulty rectifier module → fault short circuit point → internal fuse of the faulty rectifier module → negative terminal of the faulty rectifier module → DC bus negative terminal → DC bus negative terminal of the capacitor module → capacitor bank negative terminal. This huge pulse current blows the fuse in a very short time, and the faulty rectifier module ① is completely electrically isolated. The remaining normally functioning rectifier modules and lithium batteries in the system can continue to power the load, and the entire communication base station will not experience a power outage.

[0038] Without the circuit design described above, if a short circuit occurs in any rectifier slot, a short circuit point will appear inside rectifier ①, connecting the positive and negative terminals of the entire power system and causing a fatal malfunction. This is because without the capacitor module, the energy from other normally functioning rectifiers and lithium batteries alone is insufficient to blow the fuse, as the short-circuit detection and protection functions of the rectifier and lithium battery are extremely rapid, shutting down the system before the fuse blows. The capacitor module, however, can instantly release a large amount of energy to blow the fuse. The discharge current direction of the capacitor module is shown in the diagram. Figure 2 As shown, current flows from the positive terminal of the module, in the direction of the arrow, into the fuse of the faulty rectifier ①, and flows back to the negative terminal of the capacitor module, forming a discharge circuit.

[0039] Example 2: Intelligent capacitor module with energy grading and selective fuse function. This embodiment is a significant enhancement based on Embodiment 1, with the key being the addition of an intelligent control unit and the grading of the capacitor bank, which enables precise energy release control.

[0040] like Figure 3 As shown, within the capacitor module of this embodiment, the large-capacity capacitor bank is divided into four independently controllable sub-groups: the first sub-capacitor bank (30000uF), the second sub-capacitor bank (30000uF), the third sub-capacitor bank (30000uF), and the fourth sub-capacitor bank (40000uF). Each sub-group is connected to a common discharge bus via an independent controllable discharge switch (high-power IGBT). Simultaneously, an intelligent control unit is added, which is based on a 32-bit ARM Cortex-M0 microcontroller, equipped with a high-speed bus voltage sampling circuit, a capacitor bank voltage sampling circuit, and a temperature sensor.

[0041] The working process of this embodiment is as follows: Intelligent charging: After the module is inserted, the MCU detects that the bus voltage is normal and controls the controllable charging switch (a low internal resistance MOSFET) to charge all four sub-capacitor groups with a constant current of 3A. After about 40 seconds, the voltage reaches 53.2V and then switches to constant voltage float charging mode.

[0042] Fault Detection and Probe Pulse: When a rectifier short-circuit fault causes the bus voltage to drop from 53.2V to 36V within 80 microseconds, the MCU immediately detects the event and determines it as a short circuit. However, it does not immediately release all the energy. Instead, it first closes only the IGBTs connected to the first subgroup, releasing the energy stored in a capacitor of approximately 30000uF as a probe pulse. The MCU records the peak current and voltage drop slope during the discharge process using a high-speed sampling circuit.

[0043] Energy Estimation and Precise Fuse Breaking: The MCU internally contains a fuse breaking energy lookup table. This table pre-determines the relationship between the minimum breaking energy and short-circuit impedance of different rectifier fuse specifications through experiments. Based on the short-circuit loop impedance (R=V / I) measured by the test pulse, the MCU determines from the table that approximately 100 joules of energy are needed to reliably blow the current fuse. Therefore, after 40 microseconds, the MCU further closes the second and third subgroups of IGBTs. The fourth subgroup remains unconnected. The total energy is just sufficient to blow the fuse, avoiding excessive energy injection that could cause additional electrical stress to the system bus capacitors and connectors.

[0044] Post-fuse handling: After the MCU confirms through voltage sampling that the bus voltage has recovered to above 52V and the short-circuit current has disappeared, it disconnects all IGBTs and restarts the charging process for all subgroups, restoring the module to standby state.

[0045] The beneficial effects of this embodiment are that it achieves precise fault handling, improves compatibility with faulty modules of different specifications, and minimizes the impact on the system and other equipment, demonstrating a high degree of intelligence.

[0046] Example 3: Collaborative capacitor module, communicating and collaborating with lithium battery BMS This embodiment adds a communication unit to the above embodiment to enable collaborative operation with the lithium battery BMS.

[0047] like Figure 4 The diagram shown is a flowchart of this embodiment. The MCU of the capacitor module is connected to a digital input port of the lithium battery BMS via a communication unit (e.g., a simple unidirectional I / O port or a CAN transceiver). The two parties agree to the following protocol: A high level (3.3V) for 100 microseconds indicates a "delay protection request".

[0048] Low level: indicates "normal state".

[0049] When the MCU of the capacitor module detects a drop in bus voltage and determines that the rectifier is short-circuited, it sends a high-level pulse to the lithium battery BMS via the communication unit for 200 microseconds before triggering IGBT discharge (e.g., 50 microseconds in advance). Upon receiving this pulse, the lithium battery BMS immediately adjusts the response delay of its internal short-circuit protection comparator temporarily from the default 500 microseconds to 2 milliseconds. Subsequently, the capacitor module performs a discharge fuse operation (taking approximately 1 millisecond). After the fuse is broken, the MCU pulls the communication pin low. After the BMS detects the low level, it automatically restores its short-circuit protection delay to 500 microseconds in the next detection cycle (e.g., after 10 milliseconds).

[0050] Through this collaborative mechanism, the original competitive relationship—that is, the BMS shutting off the battery output before the capacitor discharge is complete—is resolved. The lithium battery BMS provides a time window for the capacitor module's fuse operation, while the capacitor module quickly completes fault isolation, so that the lithium battery does not need to enter the short-circuit protection state at all, thus maintaining the system's continuous power supply capability.

[0051] Example 4: Self-diagnostic capacitor module with failure prediction function like Figure 5 As shown, the MCU has a built-in real-time clock that is set to perform a self-diagnosis process once a day at 2:00 AM (when the base station traffic is at its lowest and the load current is at its lowest).

[0052] The self-diagnosis process is as follows: The MCU first confirms that the system is in a light-load state (e.g., total load current <10A) through the communication unit (or by directly detecting the load current).

[0053] The MCU disconnects the controllable charging switch, isolating the entire capacitor bank from the bus.

[0054] The MCU closes a built-in high-precision discharge switch, allowing the capacitor bank to discharge through a precision resistor R_test with a known resistance value.

[0055] The MCU records the voltage V(t) curve within 100 milliseconds after the start of discharge using a capacitor bank voltage sampling circuit at a sampling rate of 1 kHz.

[0056] According to the RC discharge formula The MCU calculates the current actual capacity C_actual using a curve fitting algorithm. Let be the voltage across the capacitor bank after time t has elapsed since the start of discharge. Let C be the voltage of the capacitor bank at the initial discharge moment (t=0), and let C be the actual capacitance of the capacitor bank. Let t be the known resistance value of the precision discharge resistor, and t be the time elapsed since the start of the discharge.

[0057] Simultaneously, by measuring the voltage jump value at the moment of discharge (caused by ESR), the equivalent series resistance ESR_actual = ΔV / I_discharge is calculated. Here, ΔV is the voltage jump value caused by ESR at the moment of discharge, and I_discharge is the current value at the moment of discharge.

[0058] The MCU compares the calculated C_actual and ESR_actual with the factory-specified values. For example, if it finds that the capacity has decreased by about 15% and the ESR has increased by about 33%, since the 15% capacity decrease is below the first threshold of 20% and the 33% ESR increase is below the first threshold of 100%, the MCU determines that the module is still in a healthy state and does not issue an alarm, but stores the data in the internal EEPROM for trend analysis.

[0059] A month later, the same self-diagnostic method detected a 27% decrease in C_actual, exceeding the 20% threshold. The MCU immediately issued a warning by turning the status indicator light yellow (solid on) and sending an alarm message to the host computer via the communication unit, suggesting "replace the capacitor module." However, the module was still functional at this point, only with a performance degradation.

[0060] Three months later, C_actual decayed by 54%, exceeding the second threshold of 50%. The MCU determined that the module had failed, immediately disconnected all controllable discharge switches, and closed an internal interlock switch to completely disconnect the discharge circuit. At the same time, the indicator light turned red and flashed, and reported "Module failed, interlocked".

[0061] This embodiment avoids the waste caused by traditional periodic replacement or the risk of failure due to failure to replace in time, and truly achieves intelligent maintenance-free operation.

[0062] Example 5: Overall Protection Method This embodiment describes a communication switching power supply protection method based on the capacitor module described in any of the above embodiments. For example... Figure 6 As shown, the method includes the following core steps: S1: Module deployment steps: Insert at least one capacitor module with the same shape as a standard rectifier into an unused rectifier slot in the communication switching power supply system to complete the mechanical and electrical connection.

[0063] S2: Initialization and Charging Steps: After the intelligent control unit inside the capacitor module is powered on, it first detects the DC bus voltage through the bus voltage sampling circuit. If the bus voltage is within the preset normal range (40V-58V), the charging management unit is activated, and the internal large-capacity capacitor bank is charged according to the preset safe charging curve (first current limiting and constant current, then constant voltage) until the capacitor bank voltage is approximately equal to the bus voltage, and the module enters standby mode. If the bus voltage is abnormal (below 30V), charging is prohibited and a fault alarm is issued.

[0064] S3: Real-time monitoring steps: In standby mode, the intelligent control unit continuously monitors the bus voltage in real time at a sampling frequency of not less than 20kHz, and can optionally monitor parameters such as capacitor bank voltage and temperature.

[0065] S4: Fault diagnosis steps: The intelligent control unit performs sliding window analysis on the collected bus voltage data. When the bus voltage drops within a preset very short time window (e.g., 100 microseconds) and the voltage drop exceeds a preset first threshold (e.g., 15V), and the drop is not caused by a normal load change in the system, a short circuit fault at the rectifier output terminal is determined to have occurred.

[0066] S5: Energy Release Step: Within 100 microseconds of a fault detection, the intelligent control unit triggers the rapid discharge unit. Based on a preset strategy, the following can be selected: (a) Full release: Inject all the energy of the entire capacitor bank into the bus at once.

[0067] (b) Staged release: First, release trial energy, estimate the required energy based on feedback, and then precisely release the matching energy.

[0068] The released energy forms a large instantaneous current pulse, which flows through the fuse inside the faulty rectifier module.

[0069] S6: Fault Isolation Step: The Joule heat generated by the instantaneous high current pulse within 1 millisecond causes the fuse inside the faulty rectifier to blow, thereby physically isolating the faulty rectifier from the DC bus of the system and clearing the short circuit point.

[0070] S7: Recovery and Recharging Procedure: After the intelligent control unit detects that the bus voltage has returned to the normal range and the short-circuit current has disappeared, it confirms that the fault has been isolated. It then automatically restarts the charging management unit to recharge the capacitor bank, restoring it to standby status, ready for the next possible fault.

[0071] Through the above steps, the method of the present invention can effectively solve the problem of base station power supply interruption caused by rectifier short circuit without relying on lead-acid batteries, without modifying the core parameters of lithium battery BMS, and without modifying the original switching power supply system.

[0072] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A circuit for an energy storage capacitor module used in a fuse-based protection device for faulty devices, applied in a communication switching power supply system with multiple rectifier slots, characterized in that, The system includes: At least one pluggable capacitor module, the capacitor module having the same external dimensions as the standard rectifier module of the switching power supply system, is used to be plugged into an empty rectifier slot of the switching power supply system. The capacitor module internally includes: Large-capacity capacitor banks are used to store the electrical energy needed to blow the internal fuses of the rectifier in the event of a short-circuit fault in the rectifier. The charging management unit is connected between the DC bus of the switching power supply system and the large-capacity capacitor bank, and is used to control the charging process of the capacitor bank. A fast discharge unit is connected between the large-capacity capacitor bank and the DC bus to provide a low-impedance discharge path when a rectifier short-circuit fault is detected. The intelligent control unit, including a microcontroller and a bus voltage sampling circuit, is used to monitor the system status and control the charging and discharging logic.

2. The system according to claim 1, characterized in that, The intelligent control unit is also configured to perform intelligent access and pre-charge management: When the capacitor module is inserted into an empty slot, the microcontroller detects the DC bus voltage through the bus voltage sampling circuit. If the bus voltage is within the normal operating range, the microcontroller controls the charging management unit to charge the large-capacity capacitor bank according to a preset charging curve. If the bus voltage is lower than the preset low voltage threshold, the microcontroller determines that there is a short circuit fault in the system, prohibits charging, and issues an alarm signal.

3. The system according to claim 1, characterized in that, The intelligent control unit is also configured to perform voltage drop triggering and rapid discharge: When the capacitor bank is in a fully charged standby state, the microcontroller continuously monitors the bus voltage at microsecond intervals. When the bus voltage drops by more than the preset voltage drop threshold in a very short time, the microcontroller immediately determines it as a rectifier short circuit fault event. The microcontroller controls the fast discharge unit to turn on, so that the large-capacity capacitor bank injects a large instantaneous current into the DC bus through the fast discharge unit, thereby blowing the fuse inside the faulty rectifier. The response time from voltage drop detection to discharge current output is less than 200 microseconds.

4. The system according to claim 1, characterized in that, The large-capacity capacitor bank is divided into multiple independently controllable sub-capacitor banks, each sub-capacitor bank being connected to the fast discharge unit via an independent sub-discharge switch; the intelligent control unit is also configured to execute energy grading and selective fuse mechanisms. When a rectifier short-circuit fault is triggered, the microcontroller first closes only the sub-discharge switch of the first sub-capacitor group with the least energy, releasing a tentative energy pulse; By detecting the electrical parameters of the short-circuit loop under the probe energy pulse, the microcontroller estimates the minimum fusing energy required to blow the internal fuse of the currently faulty rectifier. Based on the estimation results, the microcontroller selectively closes the sub-discharge switches of one or more other sub-capacitor groups, providing the matched total energy to blow the fuse.

5. The system according to claim 1, characterized in that, The capacitor module also includes a communication unit, which is connected to the intelligent control unit and is used to interact with the lithium battery BMS in the switching power supply system. The intelligent control unit is configured to execute a cooperative protection protocol: At the moment a rectifier short-circuit fault is detected and a decision is made to start discharging, the microcontroller sends a delayed protection request signal to the lithium battery BMS through the communication unit. After receiving the signal, the lithium battery BMS temporarily extends its short-circuit protection response time to a preset cooperative time window. After the capacitor module completes the discharge fuse operation, the microcontroller sends a signal to the lithium battery BMS to restore normal protection via the communication unit.

6. The system according to claim 1, characterized in that, The intelligent control unit is also configured to perform failure prediction and self-diagnosis functions: When the switching power supply system is under light load or idle period, the microcontroller isolates the large-capacity capacitor bank from the bus. The capacitor bank is briefly discharged using a known resistance, and the voltage-time curve during the discharge process is collected. The current actual capacity and equivalent series resistance of the capacitor bank are calculated based on the collected data. The calculation results are compared with the factory-specified values. If the capacity degradation or ESR increase exceeds the preset threshold, it is determined to be in a sub-healthy or failed state, and a corresponding warning or lockout signal is issued; specifically: If the capacity decay exceeds the first threshold or the ESR increases beyond the first threshold, it is determined to be in a sub-healthy state, and a warning signal is issued through the indicator light or communication unit. If the capacity decay exceeds the second threshold, it is determined to be in a failure state, the fast discharge unit is automatically locked, and the failure and unavailability status is reported through the communication unit.

7. A method for protecting a communication switching power supply based on a capacitor module, applied to the system according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Insert at least one capacitor module with the same shape as a standard rectifier into an unused rectifier slot in the communication switching power supply system. S2: The intelligent control unit detects the DC bus voltage. If the voltage is normal, it starts the charging management unit to charge the internal large-capacity capacitor bank, so that the capacitor bank reaches the standby state. S3: In standby mode, the intelligent control unit continuously monitors the bus voltage at a high-frequency sampling rate; S4: When a rectifier module experiences an output short-circuit fault, the bus voltage drops. S5: The intelligent control unit detects that the voltage drop exceeds the preset threshold and triggers the rapid discharge unit within 200 microseconds; S6: The large-capacity capacitor bank injects a large instantaneous current into the DC bus through the fast discharge unit. The current flows through the fuse inside the faulty rectifier, causing the fuse to blow within milliseconds, thus physically isolating the faulty rectifier from the system. S7: After the faulty rectifier is isolated, the bus voltage returns to normal, the capacitor module is recharged, and the standby state is restored.

8. The method according to claim 7, characterized in that, Step S5 further includes an energy tiered control sub-step: S51: First, release a probing energy pulse; S52: Detect the impedance characteristics of the short-circuit loop and estimate the minimum required fusing energy; S53: Based on the estimation results, selectively release precisely matched energy.

9. The method according to claim 7, characterized in that, Prior to step S5, a collaborative step with the lithium battery BMS is also included: S41: The capacitor module sends a delay protection request to the lithium battery BMS; S42: The lithium battery BMS temporarily extends its short-circuit protection response time; S43: After the capacitor module completes the discharge and blows the fuse, it sends a normal recovery protection signal to the lithium battery BMS.

10. The method according to claim 7, characterized in that, It also includes regular self-diagnosis steps: S8: During system idle periods, measure the capacitance and equivalent series resistance of the large-capacity capacitor bank inside the capacitor module; S9: Compare the measured value with the threshold. If the value exceeds the threshold, issue a warning or execute a failure lockout.

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