An overcurrent and short-circuit protection circuit of an intelligent digital power distribution module

Abstract

The application relates to the technical field of intelligent power distribution protection, in particular to an overcurrent and short-circuit protection circuit of an intelligent digital power distribution module, which comprises a plurality of power distribution module circuits, a total road regulation unit, an energy storage power supply and a fault analysis unit. The circuit is provided with a fault type discrimination and cooperative regulation mechanism, in which, in the case of non-overrun faults, normal modules share the load, in the case of overrun or short circuit, seamless switching to energy storage power supply is realized, and automatic recovery or stepwise smooth power-off is supported. The application can improve the power supply continuity, stability and load safety of a multi-module parallel system.

Description

Technical Field

[0001] This application relates to the field of power distribution module technology, and in particular to an overcurrent and short-circuit protection circuit for an intelligent digital power distribution module. Background Technology

[0002] Overcurrent and short-circuit protection circuits in intelligent digital power distribution modules are crucial devices for ensuring power continuity and load safety in multi-module parallel power supply systems during electrical faults. In modern power electronics and distribution systems, critical loads such as data centers, communication base stations, and industrial automation equipment place extremely high demands on the continuity, stability, and safety of power supply. To meet the demands for high-power, high-reliability power supply, an architecture of multiple intelligent digital power distribution modules operating in parallel is often adopted to provide power redundancy and facilitate maintenance. Typical protection schemes in existing technologies usually rely on the independent protection mechanisms of each module, such as fuses, circuit breakers, or fast-shutdown circuits based on local current / voltage detection. When an abnormality is detected, the output of that module is immediately cut off to prevent the fault from escalating.

[0003] However, existing intelligent digital power distribution module protection schemes have the following main shortcomings: When dealing with non-catastrophic overcurrent faults, the independent operation of each module leads to the direct disconnection of the faulty module, which may cause a momentary drop in the total power supply capacity of the system, resulting in bus voltage fluctuations or even load failure. They fail to fully utilize the redundant capacity of the remaining normal modules for coordinated support. When facing output short circuits or severe overloads on the bus, there is a lack of a unified coordination mechanism, and the modules may respond disorderly, generating large current surges and voltage disturbances, affecting other sensitive devices on the shared bus. Furthermore, for transient overcurrent or interference faults, traditional protection strategies typically adopt immediate shutdown, with recovery relying on manual intervention or complex restart procedures. They lack automatic judgment and smooth recovery mechanisms based on state monitoring. In handling permanent faults, they also lack phased and controllable power-off transition methods, which may adversely affect the load equipment. Summary of the Invention

[0004] This invention provides an overcurrent and short-circuit protection circuit for an intelligent digital power distribution module. By setting up a main control unit, energy storage power supply, fault analysis unit, and multi-module collaborative control mechanism, it solves the problems in the prior art of power supply interruption caused by independent operation of modules, lack of unified coordinated response, inability to achieve automatic recovery and smooth power outage transition, and improves the power supply continuity, system stability and load safety of multi-module parallel systems when facing different types of electrical faults.

[0005] This invention provides an overcurrent and short-circuit protection circuit for an intelligent digital power distribution module. The overcurrent and short-circuit protection circuit for the intelligent digital power distribution module includes: multiple power distribution module circuits, a main circuit control unit, an energy storage power supply, and a fault analysis unit.

[0006] The input terminals of the multiple power distribution module circuits are connected to an external power source, and the output terminals are connected in parallel to the load bus.

[0007] The main control unit is connected to each power distribution module circuit through a communication interface, and collects the output current and output voltage signals of each module through a current sampling resistor and a voltage divider network.

[0008] The energy storage power supply is connected between the external power supply and the load bus through a switching switch integrated inside the main circuit control unit. The switching switch is a double-pole double-throw power relay or a solid-state power switch, with its normally closed contact connected to the external power supply side and its normally open contact connected to the energy storage power supply side.

[0009] The fault analysis unit is integrated into the main control microprocessor of the main control unit and is equipped with fault type discrimination logic, collaborative control algorithm, over-limit judgment module and recovery status monitor.

[0010] Under normal operating conditions, the external power supply supplies power to the load bus through multiple power distribution module circuits, and at the same time, the energy storage power is charged by the charging management module in the main control unit under constant voltage or constant current.

[0011] When any power distribution module circuit malfunctions, the fault analysis unit determines whether it belongs to the first type of module fault or the second type of main circuit fault based on its real-time current, voltage and temperature data.

[0012] If the fault is determined to be a Class I module fault, the fault analysis unit generates a coordinated control command, and the main control unit controls the remaining normal power distribution module circuits to enter the parallel current sharing mode or the coordinated voltage and current limiting mode to share the output burden of the faulty module.

[0013] If the fault is determined to be an over-limit fault, that is, the faulty module is short-circuited, or its overcurrent exceeds the sum of the real-time available current redundancy capacity of all other normal modules, the fault analysis unit generates an energy storage switching command. The main control unit executes a timing operation to first shut down the output of all power distribution modules and then close the energy storage side switching switch to switch the load bus power supply to the energy storage power supply.

[0014] Furthermore, the fault analysis unit determines the first type of module fault based on the following criteria: comparing the current sampling value of the faulty module with a preset first overcurrent threshold; if it exceeds the threshold, it is marked as an overcurrent fault; comparing the output voltage sampling value of the faulty module with an undervoltage lockout threshold; if it is lower than the threshold, it is marked as a short circuit fault; and simultaneously, continuously monitoring the temperature of the power devices inside each module using a thermistor or digital temperature sensor; if the temperature of any module exceeds the safe temperature threshold, it is associated with and marked as a potential overload or heat dissipation fault.

[0015] Furthermore, after receiving the coordinated control command, the main control unit controls each normal power distribution module circuit to operate in one of the following two modes: In the parallel current sharing mode, by adjusting the current feedback loop setting value of each module, each normal module increases its output current proportionally without exceeding its own maximum output current limit, so as to jointly bear the total load current of the system; In the coordinated voltage reduction and current limiting mode, by synchronously reducing the voltage feedback loop reference value of each module, all parallel modules maintain operation at a lower voltage level, thereby physically limiting the short-circuit current by reducing the voltage difference without cutting off the power supply, and reducing the output pressure of a single module.

[0016] Furthermore, the logic for determining the over-limit fault specifically includes: when the fault analysis unit detects that the output voltage of any module drops to near zero and the current rises sharply, it directly determines it as a short-circuit fault and classifies it as an over-limit fault; when it is determined to be an overcurrent fault, the portion of the current of the module that exceeds the rated value is calculated as the current over-limit value, and at the same time, the difference between the current output current of all other normal modules and their maximum allowable output current is read, and the sum is accumulated to obtain the total real-time available current redundancy capacity. If the current over-limit value is greater than the total redundancy capacity, it is determined to be an over-limit fault.

[0017] Furthermore, the execution process of the energy storage switching command includes strict timing control: the main control unit first sends a shutdown signal to all power distribution module circuits to turn off their power switching devices and cut off the path from the external power supply to the load bus; then, the voltage detection circuit confirms that there is no electrical connection between the load bus and the external power supply; after confirming that the main power supply path is completely disconnected, the main control unit drives the control coil or gate drive signal of the switching switch to close the contacts on the energy storage power supply side, thus completing the power supply path switching.

[0018] Furthermore, the energy storage power supply includes an energy storage battery pack or supercapacitor pack, a charging management module, and an output control switch; the charging management module adopts a bidirectional DC-DC converter structure, which converts the external power supply voltage into a charging voltage suitable for the energy storage unit under normal conditions, and implements a constant current-constant voltage two-stage charging strategy; the output control switch is an electronic switch composed of MOSFET or IGBT, whose gate is directly controlled by the PWM drive circuit of the main control unit, which is used to complete the contact switching within 1-3ms during the switching process, and cooperates with the solid-state switch to complete the current freewheeling at the microsecond level.

[0019] Furthermore, after the system switches to energy storage power supply, the fault analysis unit starts an internal timer and continuously collects the current, voltage, and temperature signals of the original faulty module within a preset power supply maintenance time threshold. If the above signals recover to the normal operating range and remain stable for more than a preset stable duration within the time threshold, the fault analysis unit generates a system recovery command.

[0020] Furthermore, in response to the system recovery command, the main control unit executes the recovery sequence: first, it sends a soft-start signal to all power distribution module circuits to gradually build up the output voltage and enter the voltage stabilization state; after the output voltage of all modules is stable and the mutual deviation is less than the allowable tolerance, the main control unit controls the switching switch to open the energy storage side contact and close the external power supply side contact, switching the load bus back to external power supply; after the switching is completed, the charging management module is reactivated to replenish the energy storage power supply.

[0021] Furthermore, if the faulty module is not detected to have returned to normal within the power supply maintenance time threshold, the fault analysis unit generates a safety shutdown command when the time threshold is reached. In response to this command, the main control unit controls each power distribution module circuit to reduce the output power step by step according to the preset stepped power reduction curve, maintaining each step for a fixed time before entering the next step, until the output is completely shut off. During this process, the energy storage power supply continues to supply power to the load bus until the load device enters a safe low-power state, after which the main control unit disconnects the output control switch of the energy storage power supply.

[0022] Furthermore, when the fault analysis unit determines that there is a total overcurrent or short circuit based on the total current sampling value and the bus voltage sampling value, it classifies it as a second type of total fault. At this time, the fault analysis unit generates an auxiliary protection command, and the total control unit controls all power distribution module circuits to enter the coordinated voltage and current limiting mode simultaneously, reducing their respective output voltage settings according to a preset ratio, so that the total output voltage of the system decreases, thereby limiting the rise of the bus current and preventing the fault from expanding.

[0023] Beneficial effects:

[0024] This invention establishes a central control unit to manage the operating status of multiple modules. Combined with a fault analysis unit for refined fault type identification and tiered response strategies, the system avoids directly shutting down faulty modules in the event of non-catastrophic overcurrent faults. Instead, it allows other modules to collaboratively share the load, maintaining power continuity. In cases of severe short circuits or excessive overcurrent, energy storage seamlessly takes over power supply to the load, preventing bus voltage collapse. After a momentary fault is cleared, a recovery process is automatically executed without manual intervention. In permanent fault scenarios, a stepped power reduction strategy achieves smooth power outage, preventing damage to load equipment due to sudden power interruptions. Compared to existing protection methods where each module independently judges and immediately shuts down, this invention constructs an intelligent protection system with adaptive, self-diagnostic, and self-recovery capabilities through collaborative control, energy storage switching, status monitoring, and automatic recovery mechanisms. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall system structure of the overcurrent and short-circuit protection circuit of the intelligent digital power distribution module of this application;

[0027] Figure 2 This is a schematic diagram of the connection of the main control unit in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the circuit fault analysis process in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the power distribution module collaborative control process in the embodiments of this application;

[0030] Figure 5 This is a schematic diagram of the energy storage switching process in the embodiments of this application;

[0031] Figure 6 This is a timing diagram of the overcurrent and short-circuit protection of the power distribution module in the embodiments of this application. Detailed Implementation

[0032] The specific implementation of the overcurrent and short-circuit protection circuit of the intelligent digital power distribution module of the present invention is described in conjunction with the appendix. Figure 1 To be continued Figure 4 Please provide a detailed explanation. For example... Figure 1 As shown, the circuit system includes multiple power distribution module circuits 1, a main control unit 2, an energy storage power supply 3, and a fault analysis unit 4. The input terminals of the multiple power distribution module circuits 1 are connected to an external power supply 5, and their output terminals are connected in parallel to a load bus 6, forming a multi-module parallel power supply architecture. The main control unit 2 establishes bidirectional data links with each power distribution module circuit 1 through a communication interface, and collects the output current and output voltage signals of each power distribution module circuit 1 through a current sampling resistor 7 and a voltage divider network 8. The energy storage power supply 3 is connected between the external power supply 5 and the load bus 6 through a switching switch 9 integrated within the main control unit 2. The switching switch 9 is a double-pole double-throw power relay or a solid-state power switch, with its normally closed contact connected to the external power supply 5 side and its normally open contact connected to the energy storage power supply 3 side. The fault analysis unit 4 is integrated into the main control microprocessor 11 of the main control unit 2, and is used to perform logical processing such as fault type identification, collaborative control algorithm, over-limit judgment, and recovery status monitoring.

[0033] like Figure 2As shown, the main control unit 2 internally includes a current sampling resistor 7, a voltage divider network 8, a switching switch 9, a charging management module 10, and a main control microprocessor 11. The current sampling resistor 7 is connected in series in the output circuit of each power distribution module circuit 1 to detect the output current flowing through each module in real time. The voltage divider network 8 is connected in parallel between the load bus 6 and ground to obtain the voltage signal of the load bus 6. One set of moving contacts of the switching switch 9 is connected to the load bus 6, and its two stationary contacts are connected to the output terminals of the external power supply 5 and the energy storage power supply 3, respectively. The charging management module 10 adopts a bidirectional DC-DC converter structure, with its input terminal connected to the external power supply 5 and its output terminal connected to the energy storage power supply 3, used to perform constant current-constant voltage two-stage charging of the energy storage power supply 3 during normal system operation. The main control microprocessor 11 is connected to the sampling output terminals of the current sampling resistor 7 and the voltage divider network 8 through an analog-to-digital converter interface, and controls the drive coil or gate drive signal of the switching switch 9 through GPIO pins. Simultaneously, it controls the output control switch 12 in the energy storage power supply 3 through a PWM drive circuit.

[0034] Under normal operating conditions, the external power supply 5 supplies power to the load bus 6 via multiple power distribution module circuits 1. At this time, the switch 9 is normally closed, meaning the contacts on the external power supply 5 side are closed, and the contacts on the energy storage power supply 3 side are open. The main control microprocessor 11 continuously receives real-time operating parameters uploaded by each power distribution module circuit 1 through the communication interface, including output current, output voltage, and internal temperature data. Simultaneously, the charging management module 10 converts the voltage of the external power supply 5 into a charging voltage suitable for the energy storage power supply 3, charging the energy storage battery pack or supercapacitor pack to ensure that the energy storage power supply 3 is always fully charged or in a preset state of charge.

[0035] When any power distribution module circuit 1 malfunctions, the fault analysis unit 4 in the main control microprocessor 11 initiates the fault diagnosis process. For example... Figure 3 As shown, the fault analysis unit 4 first reads the current sampling value, voltage sampling value, and temperature data of the faulty module. If the current sampling value exceeds the preset first overcurrent threshold (e.g., 120% of the rated current), it is marked as an overcurrent fault; if the output voltage sampling value is lower than the undervoltage lockout threshold (e.g., 70% of the rated output voltage), it is marked as a short circuit fault; if the temperature of the power devices inside the module exceeds the safe temperature threshold (e.g., 85°C) detected by a thermistor or digital temperature sensor, it is associated with a potential overload or heat dissipation fault. Based on the above criteria, the fault analysis unit 4 classifies the fault into a first-class module fault or a second-class total circuit fault.

[0036] If the fault is determined to be a Class I module fault and does not exceed the limit, the fault analysis unit 4 generates a coordinated control command. The main control unit 2 then controls the remaining normal power distribution module circuits 1 to enter either a parallel current sharing mode or a coordinated voltage and current limiting mode. In the parallel current sharing mode, a droop control or master-slave control strategy is adopted, adjusting the PWM carrier phase or duty cycle to achieve current redistribution. The main control microprocessor 11 sends new current feedback loop settings to each normal module via the communication interface, allowing them to increase their output current proportionally without exceeding their maximum output current limit. For example, if the system was originally powered by four modules sharing the current, with a total load current of 40A and each module outputting 10A; when one module fails, the remaining three modules adjust their outputs to approximately 13.3A each, sharing the 40A load. In the collaborative voltage and current limiting mode, the main control microprocessor 11 adjusts the voltage feedback loop setting value of each normal module, so that each module synchronously reduces the output voltage setting value (such as uniformly reducing from 48V to 36V). By reducing the supply voltage, the energy release at the short circuit point is limited, while providing millisecond-level judgment time for energy storage switching.

[0037] If the fault is determined to be an over-limit fault, i.e., the faulty module has a short circuit, or its overcurrent exceeds the sum of the real-time available current redundancy capacity of all other normal modules, then the fault analysis unit 4 generates an energy storage switching command. For example... Figure 4 As shown, the main control unit 2 performs strict timing operations: First, it sends a shutdown signal to all power distribution module circuits 1 through the communication interface, causing their internal power switching devices (such as MOSFETs or IGBTs) to turn off, cutting off the path from the external power supply 5 to the load bus 6; then, the main control microprocessor 11 detects the voltage difference between the load bus 6 and the external power supply 5 through the voltage divider network 8, confirming that there is no electrical connection between the two (i.e., the voltage difference is less than a preset threshold, such as 1V); after confirming that the main power supply path is completely disconnected, the main control microprocessor 11 drives the control coil or gate drive signal of the switching switch 9, causing the normally open contact on the energy storage power supply 3 side to close, completing the power supply path switching. During this process, the output control switch 12 in the energy storage power supply 3 is directly controlled by the PWM drive circuit of the main control microprocessor 11, and conducts at the moment of switching, realizing the contact switching within 1-3ms, and cooperating with the solid-state switch to complete the current freewheeling in the microsecond level, ensuring that the voltage fluctuation of the load bus 6 does not exceed ±5%.

[0038] The energy storage power supply 3 includes an energy storage battery pack or supercapacitor pack, a charging management module 10, and an output control switch 12. Under normal conditions, the charging management module 10 operates in charging mode, converting the DC voltage (e.g., 48V) of the external power supply 5 to a charging voltage (e.g., 52V) suitable for the energy storage unit, and implementing a constant current-constant voltage two-stage charging strategy: first charging with a constant current (e.g., 5A) to near full voltage, then switching to constant voltage mode to maintain voltage stability. After switching to energy storage power supply, the charging management module 10 stops charging, the output control switch 12 remains on, and the energy storage unit directly supplies power to the load bus 6.

[0039] After the system switches to the energy storage power supply 3, the fault analysis unit 4 starts an internal timer and continuously collects the current, voltage, and temperature signals of the original faulty module through the current sampling resistor 7, the voltage divider network 8, and the temperature sensor within a preset power supply maintenance time threshold (e.g., 30 seconds). If, within this time threshold, all of the above signals recover to the normal operating range (e.g., the current drops back to within ±10% of the rated value, the voltage recovers to within ±5% of the rated value, and the temperature is below 75°C) and remain stable for more than a preset stabilization time (e.g., 5 seconds), then the fault analysis unit 4 generates a system recovery command.

[0040] In response to the system recovery command, the main control unit 2 executes the recovery sequence: First, it sends a soft-start signal to all power distribution module circuits 1 through the communication interface, so that the internal control loop gradually establishes the output voltage to avoid surge current; after all module output voltages are stable and the mutual deviation is less than the allowable tolerance (e.g., ±0.5V), the main control microprocessor 11 controls the switching switch 9 to open the energy storage side contact and close the external power supply 5 side contact, switching the load bus 6 back to the external power supply 5; after the switching is completed, the charging management module 10 is reactivated to replenish the energy storage power supply 3 and restores it to the standby state.

[0041] If the faulty module is not detected to have returned to normal within the power supply maintenance time threshold, the fault analysis unit 4 generates a safety shutdown command when the time threshold is reached. In response to this command, the main control unit 2 controls each power distribution module circuit 1 to gradually reduce its output power according to a preset stepped power reduction curve. For example, the first stage reduces the output power to 80% and maintains it for 2 seconds; the second stage reduces it to 60% and maintains it for 2 seconds; the third stage reduces it to 40% and maintains it for 2 seconds; and finally, it shuts down completely. During this process, the energy storage power supply 3 continuously supplies power to the load bus 6, ensuring that the load equipment has sufficient time to enter a safe low-power state (such as a server saving data or an industrial controller executing a shutdown procedure). After the load enters a safe state, the main control unit 2 disconnects the output control switch 12 of the energy storage power supply 3, completely cutting off the power supply.

[0042] When the fault analysis unit 4 determines that there is a total overcurrent or short circuit based on the total current sampling value (obtained through the total current sampling resistor) and the bus voltage sampling value, it classifies it as a second-type total fault. At this time, the fault analysis unit 4 generates an auxiliary protection command, and the total control unit 2 controls all power distribution module circuits 1 to simultaneously enter the coordinated voltage and current limiting mode. The output voltage setting of each module is reduced according to a preset ratio (e.g., the output voltage of each module drops to 80% of its original setting value), causing the total system output voltage to decrease, thereby limiting the rate of increase of the bus current and preventing the fault from escalating. For example, in a 48V system, the total output voltage is temporarily reduced to 38.4V, which can effectively suppress the current surge caused by a load short circuit.

[0043] Throughout operation, communication between the main control unit 2 and each power distribution module circuit 1 utilizes the CAN bus or RS485 protocol to ensure real-time and reliable command transmission. The main control microprocessor 11 employs an ARM Cortex-M series chip, with a built-in high-precision ADC for signal sampling and a hardware watchdog timer and fail-safe mechanism. When a solid-state power switch 9 is selected, its switching speed can reach the microsecond level, significantly superior to mechanical relays, making it suitable for high-frequency switching scenarios. The supercapacitor bank in the energy storage power supply 3 is suitable for applications requiring rapid charging and discharging and high cycle life, while the lithium-ion battery bank is suitable for long-term standby scenarios requiring high energy density.

[0044] Through the coordination of the above structure and control logic, this invention achieves the following: in the event of a non-catastrophic overcurrent fault, the faulty module is not directly disconnected, but the remaining modules collaboratively share the load; in the event of a severe short circuit or excessive overcurrent, the energy storage power supply seamlessly takes over the load power supply; after the transient fault is cleared, the recovery process is automatically executed; and in the event of a permanent fault, a stepped power reduction strategy is used to achieve smooth power outage. The positional relationships, electrical connections, and control timing of all key components are detailed in the appendix. Figure 1 To be continued Figure 4 It is clearly indicated that those skilled in the art can fully reproduce the technical solution of the present invention based on this embodiment.

[0045] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principles of this invention are further supplemented below with a specific application scenario.

[0046] In the data center server rack power supply system, four intelligent digital power distribution module circuits 1 are deployed in parallel and connected to an external power supply 5, jointly providing 48V DC power to the load bus 6 to support the operation of multiple critical servers. The main control unit 2 establishes a communication connection with each power distribution module circuit 1 via a CAN bus, and integrates a current sampling resistor 7, a voltage divider network 8, a switching switch 9, a charging management module 10, and a main control microprocessor 11. The energy storage power supply 3 consists of a group of supercapacitors, connected to the load bus 6 via the switching switch 9, and its output terminal is equipped with an output control switch 12 controlled by the main control microprocessor 11 through a PWM drive circuit.

[0047] When one of the power distribution module circuits 1 experiences a sudden increase in load, causing its output current to rise instantaneously to 12.5A (rated value is 10A), exceeding the first overcurrent threshold (120% of rated current, i.e., 12A) but without a short circuit, the fault analysis unit 4 reads the module's current sampling value, the bus voltage fed back by the voltage divider network 8, and the data from the module's internal temperature sensor. Since the voltage remains at 46V (above 70% of the rated voltage, 33.6V) and the temperature is 78℃ (below the 85℃ safety threshold), the fault analysis unit 4 determines it to be a Class I module fault that is within limits. At this time, the main control microprocessor 11 sends a coordinated control command to the other three normal power distribution module circuits 1 via the CAN bus, adjusting their current feedback loop setting value from 10A to 13.3A, so that the three can share the original total load current of 40A. This process is achieved by dynamically adjusting the PWM duty cycle through the digital control loop inside each module, ensuring that the current sharing error is less than ±2%, thereby avoiding a sudden drop in bus voltage due to the disconnection of a single module.

[0048] If a short circuit occurs at the output of a power distribution module circuit 1, its output voltage drops rapidly to 10V, while the current surges to 30A, far exceeding the combined redundancy capacity of the other three modules (maximum 30A, currently handling a 40A load, redundancy is 0). The fault analysis unit 4 determines it as an over-limit fault based on the voltage being below the undervoltage lockout threshold and the overcurrent amplitude. The main control microprocessor 11 immediately sends a shutdown signal to all power distribution module circuits 1 via the CAN bus, setting their internal MOSFET drive signals to zero and cutting off the power path. Subsequently, the main control microprocessor 11 detects the residual voltage difference between the load bus 6 and the external power supply 5 through the voltage divider network 8. After confirming that it is less than 1V, it drives the gate signal of the switching switch 9, causing its normally open contact to close. At the same time, the PWM drive circuit synchronously turns on the output control switch 12, enabling the energy storage power supply 3 to complete the power supply switching within 2 milliseconds. Due to the low ESR characteristics of the supercapacitor, its discharge response speed is fast. Combined with the switching timing control, the voltage fluctuation of the load bus 6 is controlled within ±3%, meeting the server's power stability requirements.

[0049] During the period when the energy storage power supply 3 maintains power supply, the fault analysis unit 4 starts a 30-second timer and continuously monitors the circuit current of the original faulty module through the current sampling resistor 7. If the short circuit point is naturally eliminated due to loose contact after 5 seconds, the current drops back to 9.8A, the voltage recovers to 47.5V, the temperature drops to 72℃, and the above state lasts for more than 5 seconds, then the fault analysis unit 4 generates a system recovery command. The main control microprocessor 11 first sends a soft start command to each power distribution module circuit 1, causing its output voltage to rise from 0V to 48V according to an exponential curve, with the rise time set to 200ms to suppress surges; after the deviation of the four output voltages is less than ±0.4V, the control switch 9 is reset to the normally closed state, and the external power supply 5 is reconnected; after the switching is completed, the charging management module 10 starts constant current-constant voltage charging, charging the supercapacitor voltage from 45V to 52V with a current of 5A, restoring the energy storage standby state.

[0050] If the fault is not eliminated within 30 seconds, such as a persistent short circuit, the fault analysis unit 4 triggers a safety shutdown procedure at the end of the timeout. The main control microprocessor 11 controls each power distribution module circuit 1 to reduce the output power according to a preset stepped curve: first, the PWM duty cycle is adjusted to 80%, corresponding to an output power reduction to 32A, maintained for 2 seconds to supply the server operating system for cache writing; then it is reduced to 60% (24A) and maintained for 2 seconds, then reduced to 40% (16A) and maintained for 2 seconds, and finally completely shut down. During this process, the energy storage power supply 3 continues to supply power to ensure that the server completes the safe shutdown procedure. Once the load bus 6 current drops below 1A, the main control microprocessor 11 turns off the output control switch 12, completely isolating the energy storage power supply 3.

[0051] When the load bus 6 experiences an abnormal increase in total current to 60A (system rated 50A) due to an internal short circuit in downstream equipment, the fault analysis unit 4 obtains the total current value through the total current sampling resistor and, combined with the voltage divider network 8, detects a bus voltage drop to 35V, classifying it as a type II total circuit fault. The main control microprocessor 11 then sends a parallel voltage divider command to all power distribution module circuits 1, uniformly adjusting their output voltage settings from 48V to 38.4V (80% ratio). Each module adjusts the reference voltage of its internal voltage feedback loop to synchronously reduce the actual output voltage, thereby limiting the short-circuit current within a safe range and preventing malfunctions of protection devices or equipment damage.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An overcurrent and short-circuit protection circuit for an intelligent digital power distribution module, characterized in that, include: Multiple power distribution module circuits, main circuit control unit, energy storage power supply and fault analysis unit; The input terminals of the multiple power distribution module circuits are connected to an external power source, and the output terminals are connected in parallel to the load bus. The main circuit control unit is connected to the multiple power distribution module circuits and is used to monitor and control their current and voltage; The energy storage power supply is connected between the external power supply and the load bus via a switching switch within the main circuit control unit; The fault analysis unit is located within the main circuit control unit; wherein, under normal conditions, the external power supply supplies power to the load bus through the multiple power distribution module circuits and simultaneously charges the energy storage power supply. The fault analysis unit is used to: analyze whether a first-type module fault or a second-type total circuit fault has occurred based on the signals of each power distribution module circuit; when the analysis indicates a first-type module fault, generate a coordinated control command to control other normal power distribution module circuits to perform coordinated protection; when the fault analysis unit analyzes the total circuit current signal and bus voltage signal to indicate a total circuit overcurrent or short circuit, determine it as a second-type total circuit fault, and generate an auxiliary protection command to control all power distribution module circuits to enter a coordinated voltage and current limiting mode, synchronously reducing their output voltage setpoints according to a preset ratio to achieve coordinated voltage and current limiting of the total circuit; when the analysis indicates an over-limit fault exceeding the coordinated control capability, generate an energy storage switching command. The main control unit responds to the energy storage switching command by controlling the switching switch to switch the power supply source of the load bus from the external power supply to the energy storage power supply.

2. The circuit according to claim 1, characterized in that, The output terminals of the plurality of power distribution module circuits are connected in parallel to the load bus, the main circuit control unit is connected to the control terminal of each of the power distribution module circuits, and the energy storage power supply is connected in parallel between the external power supply and the load bus through the switching switch.

3. The circuit according to claim 1, characterized in that, The fault analysis unit's analysis of the first type of module faults includes: An overcurrent fault is determined by comparing the current signal of the faulty module with the first overcurrent threshold. By comparing the voltage signal of the faulty module with the undervoltage lockout threshold, an undervoltage fault is determined. The temperature of each module is continuously monitored. When the temperature of a module exceeds the safe temperature threshold, it is identified as a potential overload or heat dissipation failure.

4. The circuit according to claim 1, characterized in that, In response to the coordinated control command, the main control unit controls the multiple power distribution module circuits to operate in one of two coordinated modes: In the parallel current sharing mode, the output current setting value of each normal module is adjusted to increase its output so as to share the total load current of the system. Alternatively, a collaborative voltage and current limiting mode can be used, which synchronously reduces the reference value of the output voltage of each module to achieve collaborative suppression of short-circuit current.

5. The circuit according to claim 1, characterized in that, The over-limit fault refers to: any power distribution module experiencing a short circuit, or its overcurrent reaching the sum of the maximum current shunting capacity of all other normal power distribution modules, yet still failing to achieve effective control. The analysis logic for the over-limit fault includes: When a short-circuit fault is identified, it is directly classified as an over-limit fault. When an overcurrent fault is identified, the current excess value of the faulty module is calculated, and this excess value is compared with the sum of the real-time available current redundancy capacity of all other normal modules. If the excess value is greater than the sum of the redundancy capacity, it is identified as an over-limit fault.

6. The circuit according to claim 1 or 5, characterized in that, The execution of the energy storage switching command includes a timing control process: The main control unit first controls the shutdown of the output of all the power distribution module circuits to cut off the power supply path from the external power source; After confirming that the main power supply path is disconnected, the switching switch is closed to switch the load bus power supply link to the energy storage power source.

7. The circuit according to claim 1, characterized in that, The energy storage power supply includes an energy storage battery pack or supercapacitor pack, a charging management module, and an output control switch. The charging management module manages the charging of the energy storage battery pack or supercapacitor pack by the external power source under normal conditions; the output control switch, as part of the switching switch, is directly controlled by the main circuit control unit when it is turned on or off.

8. The circuit according to claim 1, characterized in that, The fault analysis unit is also used to start an internal timer after the system switches to the energy storage power supply, and to continuously monitor the status of the original fault module within a preset power supply maintenance time threshold. When the electrical and thermal states are monitored to return to normal within the power supply maintenance time threshold and remain stable for a preset period of time, it is determined that the fault has been temporarily eliminated and a system recovery command is generated.

9. The circuit according to claim 8, characterized in that, In response to the system recovery command, the bus control unit executes a recovery sequence: The multiple power distribution module circuits are restarted and their outputs are stabilized. After the module outputs are stabilized, the switching switch is controlled to switch the load bus power supply link from the energy storage power supply back to the external power supply. After the switch is completed, the energy storage power supply is controlled to re-enter the state of being charged by an external power source.

10. The circuit according to claim 8, characterized in that, The fault analysis unit is also used for, If the fault is not cleared within the power supply maintenance time threshold, a safety shutdown command is generated when the time threshold is reached. In response to the safety shutdown command, the main control unit controls the multiple power distribution module circuits to smoothly transition to complete power failure in a phased and stepped manner by reducing the output power. During this process, the energy storage power supply maintains power supply until the load enters a safe low-power state, and finally disconnects the energy storage power supply.

11. The circuit according to claim 1, characterized in that, Under normal conditions, the electrical energy from the external power source is delivered to the load bus via the multiple parallel power distribution module circuits, and charges the energy storage power source, forming a main power supply circuit and a charging circuit.

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