A multi-source redundant power supply intelligent switching system and method

Abstract

The application discloses a kind of multi-source redundant power intelligent switching system and method, it is related to power supply control technical field, the system includes: dynamic threshold ideal diode, multi-source power supply unit, double distribution bus and protection circuit;Dynamic threshold ideal diode includes controller and metal oxide semiconductor field effect transistor, controller is built-in dynamic voltage threshold detection circuit;Multi-source power supply unit includes main power supply and backup power supply, main power supply includes high-voltage DCDC power converter and ground power supply, backup power supply uses several groups of low-voltage battery of low-voltage battery system, multistage redundancy design is used between three;Double distribution bus includes first and second distribution bus, and both are horizontal redundancy state;Protection circuit includes overvoltage protection circuit, electrostatic discharge protection circuit and transient voltage suppression circuit.The application is matched by dynamic threshold ideal diode, multi-source power supply unit and double distribution bus, realizes the accurate, fast switching of multi-source power on double bus.

Description

Technical Field

[0001] This invention relates to the field of power supply control technology, and in particular to a multi-source redundant power supply intelligent switching system and method. Background Technology

[0002] As a core piece of equipment for low-altitude aviation, the continuous and stable power supply of eVTOL's airborne electronic equipment directly determines flight safety. Therefore, its low-voltage power distribution system generally adopts a multi-source redundant input power architecture, integrating high-voltage DC-DC power converters, ground power supplies, and multiple sets of low-voltage batteries as power supply units to provide power to core airborne equipment such as flight control, navigation, and sensing.

[0003] Aviation-grade power distribution systems have stringent requirements for the speed, accuracy, and seamlessness of power switching. They must achieve core functions such as zero power consumption of the backup power supply when the main power supply is on, instantaneous takeover of the backup power supply when the main power supply fails, and balanced and coordinated voltage of multiple backup power supplies. However, existing power switching systems mostly use conventional diode or relay architectures, which lack precise voltage threshold control logic. Furthermore, the on-state voltage drop of ordinary diodes is fixed, making it impossible to achieve precise voltage threshold control at the millivolt level. This can easily lead to chaotic multi-power supply logic, problems such as backflow from low-potential power supplies and failure of power supply control competition for high-potential power supplies, making it difficult to adapt to the high reliability power supply requirements of eVTOL. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a multi-source redundant power supply intelligent switching system and method, which realizes independent, accurate and fast switching of multi-source power supplies on dual busbars through the cooperation of dynamic threshold ideal diodes, multi-source power supply units and dual power distribution buses.

[0005] To solve the above-mentioned technical problems, the present invention provides a multi-source redundant power supply intelligent switching system. The system includes: a dynamic threshold ideal diode, a multi-source power supply unit, a dual power distribution bus, and a protection circuit. The dynamic threshold ideal diode is connected to the dual power distribution bus, and the protection circuit is connected to the dynamic threshold ideal diode and the multi-source power supply unit respectively. The dynamic threshold ideal diode includes a controller and a metal-oxide-semiconductor field-effect transistor, the controller is connected to the metal-oxide-semiconductor field-effect transistor, and the controller has a built-in dynamic voltage threshold detection circuit. The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC power converter and a ground power supply. The backup power supply adopts a low-voltage battery system. The low-voltage battery system includes several groups of low-voltage batteries. The high-voltage DC-DC power converter, the ground power supply and the low-voltage battery system adopt a multi-level redundancy design. The dual power distribution bus includes a first power distribution bus and a second power distribution bus, and the first power distribution bus and the second power distribution bus are in a horizontal redundancy state. The protection circuit includes an overvoltage protection circuit, an electrostatic discharge protection circuit, and a transient voltage suppression circuit.

[0006] Optionally, the controller uses an LTC4357 core control chip, and the GATE pin of the LTC4357 core control chip is connected to the metal-oxide-semiconductor field-effect transistor.

[0007] Optionally, the metal-oxide-semiconductor field-effect transistor is an IPT015N10N5 metal-oxide-semiconductor field-effect transistor.

[0008] Optionally, the dynamic voltage threshold detection circuit includes a forward voltage drop comparator, a gate amplifier, and a charge pump.

[0009] Optionally, the multi-level redundancy design includes primary redundancy, secondary redundancy, and tertiary redundancy. Primary redundancy includes a high-voltage DC-DC power converter, a ground power supply, and a low-voltage battery system. Secondary redundancy includes several groups of low-voltage batteries within the low-voltage battery system. Tertiary redundancy includes a first distribution bus and a second distribution bus.

[0010] In addition, the present invention also provides a method for intelligent switching of multi-source redundant power supplies, which is implemented based on the above-mentioned intelligent switching system for multi-source redundant power supplies, and the method includes: The dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage. The voltage difference is compared with a preset threshold to obtain a comparison result, and the shutdown logic of the multi-source power supply unit is triggered based on the comparison result. Coil fault detection was performed on the dual power distribution busbars, and the coil fault detection results were obtained. Based on the coil fault detection results, fault isolation operation analysis is performed to obtain fault isolation operation information, and seamless power switching is performed based on the shutdown logic and fault isolation operation information.

[0011] Optionally, the dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage, including: The real-time voltage output by the multi-source power supply unit is sampled by the IN and OUT pins of the controller in the dynamic threshold ideal diode. The voltage difference is calculated using the real-time voltage based on the dynamic voltage threshold detection circuit.

[0012] Optionally, comparing the voltage difference with a preset threshold to obtain a comparison result, and triggering the shutdown logic of the multi-source power supply unit based on the comparison result, includes: If the voltage difference is greater than or equal to a preset threshold, the multi-source power supply unit is determined to be in a normal conducting state, and there is no need to trigger a shutdown operation. If the voltage difference is less than a preset threshold, it is determined that the multi-source power supply unit is in a reverse current state, triggering the shutdown operation of the multi-source power supply unit.

[0013] Optionally, the step of performing coil fault detection on the dual distribution busbars and obtaining coil fault detection results includes: Perform coil disconnection detection on the dual power distribution busbars and obtain the coil disconnection detection results; The coil voltage of the dual power distribution bus is detected to obtain coil voltage information. Overvoltage fault detection is performed based on the coil voltage information to obtain overvoltage fault detection results. The coil fault detection result is determined based on the coil disconnection detection result and the overvoltage fault detection result.

[0014] Optionally, the step of performing fault isolation operation analysis based on the coil fault detection results to obtain fault isolation operation information includes: Based on the coil fault detection results, the conduction priority and load current completion information of the dynamic threshold ideal diode are determined, and the first operation information is determined based on the conduction priority and load current completion information. Based on the coil fault detection results, the cut-off operation information of the protection circuit and the current turn-off information of the dynamic threshold ideal diode are determined, and the second operation information is determined based on the cut-off operation information and the current turn-off information. Fault isolation operation information is determined based on the first operation information and the second operation information.

[0015] In this embodiment of the invention, the dynamic threshold ideal diode includes a controller and a metal-oxide-semiconductor field-effect transistor. The controller has a built-in dynamic voltage threshold detection circuit, which can accurately identify the voltage difference between multiple power sources, achieve millivolt-level power supply decision-making, avoid the problem of low-potential power supply backflow to high-potential power source, and improve the accuracy of power switching. The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC power converter and a ground power supply. The backup power supply adopts a low-voltage battery system. The cooperation between the multi-source power supply unit and the dynamic threshold ideal diode enables zero-power switching between main and backup power supplies, ensuring backup capability. The high-voltage DC-DC power converter, ground power supply, and low-voltage battery system adopt a multi-level redundancy design. When a single power supply fails, the system can still supply power normally, greatly improving fault resistance. Through the cooperation of the dynamic threshold ideal diode, the multi-source power supply unit, and the dual power distribution bus, independent, accurate, and rapid switching of multiple power sources on the dual bus is achieved. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structural composition of the multi-source redundant power supply intelligent switching system in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the intelligent switching method for multi-source redundant power supplies in an embodiment of the present invention. Figure 3 This is a schematic diagram of the circuit structure of the intelligent switching system for multi-source redundant power supplies in an embodiment of the present invention; Figure 4 This is a schematic diagram of the circuit structure of the dynamic threshold ideal diode in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 like Figure 1 and Figure 3 As shown, Figure 1 This is an embodiment of an intelligent switching system for multi-source redundant power supplies in this invention. Figure 3 This is a circuit structure diagram of a multi-source redundant power supply intelligent switching system in an embodiment of the present invention. The system includes: a dynamic threshold ideal diode, a multi-source power supply unit, a dual power distribution bus, and a protection circuit. The dynamic threshold ideal diode is connected to the dual power distribution bus, and the protection circuit is connected to both the dynamic threshold ideal diode and the multi-source power supply unit. The dynamic threshold ideal diode includes a controller and a metal-oxide-semiconductor field-effect transistor, the controller is connected to the metal-oxide-semiconductor field-effect transistor, and the controller has a built-in dynamic voltage threshold detection circuit. The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC power converter and a ground power supply. The backup power supply adopts a low-voltage battery system. The low-voltage battery system includes several groups of low-voltage batteries. The high-voltage DC-DC power converter, the ground power supply and the low-voltage battery system adopt a multi-level redundancy design. The dual power distribution bus includes a first power distribution bus and a second power distribution bus, and the first power distribution bus and the second power distribution bus are in a horizontal redundancy state. The protection circuit includes an overvoltage protection circuit, an electrostatic discharge protection circuit, and a transient voltage suppression circuit.

[0020] In the specific implementation of this invention, the dynamic threshold ideal diode is the core switching device of the system. It adopts a pure hardware combination architecture of controller + metal-oxide-semiconductor field-effect transistor (MOSFET), with a built-in 25mV dynamic voltage threshold detection circuit and a MOSFET turn-off / turn-on response speed of 0.5μs. Each power supply unit corresponds to at least two ideal diodes, which are respectively connected to the first power distribution bus and the second power distribution bus, realizing independent power supply switching of a single power supply to two buses.

[0021] The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC converter and a ground power supply. The high-voltage DC-DC converter is powered by an 800V high-voltage battery and has a constant output of DC49V. The ground power supply is AC input and has a constant output of DC50V. The backup power supply uses a low-voltage battery system, which includes several groups of low-voltage batteries, which can be 48V low-voltage batteries, to provide redundant backup for the main power supply. The high-voltage DC-DC converter, the ground power supply, and the low-voltage battery system adopt a multi-level redundancy design.

[0022] The dual power distribution bus includes a first power distribution bus and a second power distribution bus. The first power distribution bus and the second power distribution bus are in a lateral redundancy state. The first power distribution bus and the second power distribution bus are two independent power distribution buses that provide power to the airborne electronic equipment of the electric vertical take-off and landing (eVTOL) aircraft, thus achieving lateral redundancy. When a single power distribution bus fails, the other power distribution bus can independently complete the power supply, avoiding power interruption. The lateral redundancy of the first power distribution bus and the second power distribution bus is achieved through the following design: (1) Physical dual channel: Set up an electrically independent first power distribution bus and a second power distribution bus. (2) Dual access of all power supply: All power supply units are connected to the two power distribution buses through two sets of independent ideal diode modules, so that any power supply can supply power to any power distribution bus. (3) Fault tolerance logic: When a bus fails (such as a short circuit), its voltage will drop sharply. At this point, all ideal diode modules connected to the faulty bus will quickly turn off within 0.5μs due to the detection that the input voltage is much lower than the output (load) voltage (i.e., reverse current condition), thus automatically isolating the faulty bus from the system. Afterward, all loads will continue to be powered by another healthy bus through its corresponding ideal diode module, achieving the aerospace-grade redundancy requirement that a single point of failure does not affect system functionality.

[0023] The protection circuit includes overvoltage protection, electrostatic discharge (ESD) protection, and transient voltage suppression. It suppresses overvoltage, surges, and ESD interference during power supply, ensuring system electrical safety and adapting to the airborne electromagnetic environment of eVTOL. The ESD protection circuit primarily consists of bidirectional ESD protection devices (such as the electronic SJD12C60L01 device), connected in parallel between the positive and negative power input terminals. Its function is to absorb instantaneous high-voltage pulses generated by static electricity from the human body or tools, protecting the sensitive pins of subsequent chips. Transient voltage suppression mainly consists of bidirectional transient voltage suppression diodes (such as the SMBJ series), also connected in parallel at the power input terminals. Its function is to clamp higher-energy voltage surges caused by lightning strikes, inductive load switching, etc., preventing overvoltage damage to subsequent circuits. Typically, the transient voltage suppression circuit (handling high-energy surges) and the ESD protection circuit (handling fast static electricity) are used in combination to form a multi-level protection network against different transient interferences, jointly ensuring the electrical safety of the system in complex airborne electromagnetic environments.

[0024] In a specific implementation of this invention, the controller employs an LTC4357 core control chip, and the GATE pin of the LTC4357 core control chip is connected to the metal-oxide-semiconductor field-effect transistor (MOSFET). The MOSFET is an IPT015N10N5 MOSFET. The dynamic voltage threshold detection circuit includes a forward voltage drop comparator, a gate amplifier, and a charge pump.

[0025] Specifically, such as Figure 4 As shown, the controller for the ideal diode uses the LTC4357 core control chip. This chip integrates a high-speed comparator, providing 25mV dynamic voltage threshold detection and 0.5μs-level MOSFET turn-off drive. It drives an external N-channel MOSFET to replace the Schottky diode, providing the hardware foundation for achieving millivolt-level precise and seamless switching. In diode or high-current diode applications, it can reduce power consumption, heat dissipation, voltage drop, and printed circuit board area. It can achieve power-on or operation, improving system reliability. As a positive high-voltage ideal diode controller, the LTC4357 chip is responsible for voltage detection, logic judgment, and gate drive, controlling the forward voltage drop across the MOSFET to ensure a smooth current transfer from one path to another without oscillation. In the event of a power supply failure or short circuit, rapid turn-off minimizes reverse current transients. Its package and pinout are compatible with onboard high-density printed circuit board (PCB) designs.

[0026] The LTC4357 core control chip is packaged in an 8-pin Miniature Small Outline Package (MSOP), with a compact size (approximately 3mm × 4.9mm). Compared to traditional diodes, it saves more than 40% of PCB area, meeting the miniaturization requirements of eVTOL power distribution boxes. Some models offer a 6-pin DFN (2mm × 3mm) package for further space reduction. Core pin functions: 1) IN / OUT pin: Real-time sampling of input (power supply) and output (load) voltages, detecting the voltage difference to determine the current direction, with a sampling frequency ≥1MHz (ensuring fast response); 2) GATE pin: Output drive voltage (maximum +12V, minimum -12V), controlling the on and off of the external MOSFET. Strong pull-down ensures rapid cutoff during turn-off.

[0027] MOSFETs are actuators of ideal diodes, responsible for carrying the main circuit current. Their selection needs to match the current level and loss requirements of the specific avionics equipment in eVTOL. Their low on-resistance (Rds(on)) is the key to achieving low-loss power supply (replacing Schottky diodes). In the dual-bus power supply circuit design of the distribution box, Infineon series N-channel MOSFETs with different rated currents are selected for different circuit nodes according to the current level of the link. The IPT015N10N5 metal-oxide-semiconductor MOSFET is used as the external MOSFET. Its key parameters are: drain-source voltage (Vdss) 100V (covering eVTOL 28V / 48V bus voltage), continuous drain current (Id) 300A (meeting the peak current requirements of servo motors, flight controllers and other equipment), and on-resistance (RDS (on)) 2mΩ@6V (low conduction loss). Functional adaptation: driven by the GATE pin of IPT015N10N5, the MOSFET is equivalent to a low-resistance path when forward conducting and quickly cut off when reverse conducting, replacing the unidirectional conduction function of the traditional Schottky diode, while reducing the forward voltage drop (≤0.1V) and power loss (more than 75% lower than Schottky diode).

[0028] The dynamic voltage threshold detection circuit includes a forward voltage drop comparator, a gate amplifier, and a charge pump. The forward voltage drop comparator is used to monitor the voltage difference between IN and OUT, the gate amplifier is used to monitor the voltage difference between OUT and IN, and the charge pump is used to provide a 17V boost voltage to drive the gate of the N-channel MOSFET, ensuring that the MOSFET is fully turned on and reducing the on-resistance.

[0029] The working principle of an ideal diode: The voltage between the source and drain of the LTC4357 device is monitored by the IN and OUT pins, while the GATE pin drives the MOSFET to control its operating state. In fact, the source and drain of the MOSFET are equivalent to the anode and cathode of an ideal diode. The dynamic voltage threshold detection function is implemented by the core chip LTC4357, which integrates a high-speed voltage comparator. Specifically, this is reflected in the circuit as follows: a) Sampling: The IN and OUT pins of the chip sample the voltage at the power supply terminal (input terminal) and the load terminal (output terminal / bus terminal) in real time, respectively. b) Comparison and judgment: The internal circuit compares the voltage difference (VIN - VOUT) between IN and OUT. When the difference is greater than 25mV, it is determined to be normal or in a state requiring conduction. When the difference is less than -25mV, it is determined to be a reverse current, triggering the shutdown logic. c) Execution: Based on the comparison result, the corresponding drive voltage (e.g., +12V for conduction, -12V for shutdown) is output through the GATE pin to control the external MOSFET.

[0030] This 25mV dynamic threshold is an inherent characteristic parameter of the LTC4357 chip, requiring no complex external circuitry to implement, and forms the basis for achieving millivolt-level precise switching. When applied to power supply decision-making in eVTOL multi-source redundancy systems, it is precisely this millivolt-level precision threshold that enables voltage balancing coordination, zero-power switching between primary and backup systems, and oscillation-free smooth switching—effects unattainable by existing technologies.

[0031] Upon power-up, the load current initially flows through the body diode of the MOSFET, creating a forward voltage drop between the IN and OUT pins. The LTC4357 detects this voltage drop and boosts the voltage at the GATE pin, turning on the MOSFET and stabilizing the forward voltage drop between its source and drain at 25mV. When the load current increases, causing the forward voltage drop to exceed 25mV, the forward voltage drop is determined by RDS(on) × ILOAD. When the load current decreases, causing the forward voltage drop to fall below 25mV, the GATE pin is pulled down weakly to reduce the drive voltage, maintaining the voltage drop at 25mV. When reverse current occurs and the IN and OUT voltage difference falls below -25mV, the LTC4357 turns off the MOSFET within 500ns via a strong pull-down, blocking the reverse current.

[0032] In the event of a power supply failure, such as a sudden short circuit to ground at a fully loaded power output, reverse current will temporarily flow through the MOSFET that is in the ON state. This current originates from any load capacitance and other power sources. The LTC4357 can respond quickly to this situation, turning off the MOSFET within approximately 0.5μs, thereby minimizing interference to the output bus.

[0033] The outputs of multiple redundant power supplies are combined using ideal diodes. Load current is initially drawn from the highest output terminal, and as the output voltage decreases with increasing load, the lower output terminals also contribute. A 25mV regulation technique ensures smooth load distribution among the outputs without oscillation.

[0034] It should be noted that dynamic threshold ideal diodes play a crucial role in eVTOL low-voltage distribution boxes by providing core functions such as reverse current blocking, seamless power switching, fault isolation, and low-loss power supply. They directly address the problems of slow response, fault propagation, and high power consumption in traditional power distribution systems.

[0035] (a) Reverse current blocking: 0.5μs level fast turn-off to prevent power supply mutual charging and device damage. This is the core basic function of the ideal diode. Its working principle is based on voltage difference judgment + strong gate pull-down: (1) Detection logic: When the IN pin voltage is lower than the OUT pin voltage (i.e., current reverse, voltage difference < -25mV), the internal comparator of the LTC4357 chip immediately triggers the turn-off logic; (2) Execution speed: The GATE pin pulls the drive voltage down to -12V within 0.5μs, so that the MOSFET is quickly turned off (turn-off delay ≤ 300ns), blocking the reverse current path; (3) eVTOL scenario value: When the DC-DC module on a certain bus is short-circuited (such as the first power distribution bus suddenly loses power), it can prevent the current of another normal bus (such as the second power distribution bus) from flowing back to the faulty module, avoiding damage to core equipment such as flight control and servo due to reverse current impact. The response speed is 1000 times faster than traditional software control (more than 500μs).

[0036] (b) Seamless power supply switching: Dynamic threshold control enables oscillation-free collaborative power supply from multiple power sources. For the eVTOL dual-bus redundant design (both the first and second distribution buses are multiple power sources combined for output), the ideal diode achieves smooth switching of multiple power sources through a 25mV dynamic voltage threshold. a) Cooperative power supply logic: When the voltage difference between the two power supplies is ≤25mV, the LTC4357 chip controls the corresponding MOSFETs to remain on, and the current is distributed according to the voltage ratio (e.g., the 49V and 48V buses bear 52% and 48% of the load current respectively), avoiding single power supply overload; b) Oscillation-free switching: When the voltage of a power supply fluctuates (e.g., the difference >25mV due to changes in the output of the DC-DC module), the MOSFET on the low potential side is turned off within 0.5μs, while the MOSFET on the high potential side remains on, with the output voltage fluctuation ≤±0.5V, meeting the power supply stability requirements of avionics such as eVTOL servos (allowable fluctuation ≤±1V) and flight controllers (allowable fluctuation ≤±0.3V); c) Differentiated advantages: Unlike the hard switching of traditional or logic diodes (which is prone to voltage spikes), this function eliminates oscillations through dynamic threshold control, avoiding electromagnetic interference to sensitive airborne equipment.

[0037] (c) Fault Isolation: In collaboration with relays, a dual-bus redundant protection closed loop is constructed. In the eVTOL dual-bus independent isolation system, ideal diodes and relays form a collaborative mechanism of fault recovery and overvoltage protection. a) Relay Fault Power Supply: When a relay on a certain bus is disconnected due to a coil fault, the ideal diode on the corresponding bus channel detects the current interruption (sudden change in IN / OUT voltage difference) and immediately triggers the ideal diode on the other bus to increase its conduction priority, replenishing the load current within 0.5μs to ensure uninterrupted output voltage. b) Relay Overvoltage Protection: The relay coil power supply circuit is connected in series with an overvoltage protection circuit based on the LTC4367 chip. When the coil voltage is >30V, the overvoltage module cuts off the power supply, and the ideal diode simultaneously turns off the corresponding bus current to prevent bus short circuits caused by contactor sticking, forming a closed-loop protection of overvoltage-cut-off-isolation. d) Scenario Adaptability: This function solves the risk of power interruption caused by single-point failure of relays during eVTOL flight, which meets the requirements of aviation-grade redundancy design (single-point failure does not affect system function).

[0038] (d) Low-loss power supply: Replacing Schottky diodes reduces onboard power consumption. eVTOL's endurance is sensitive to power consumption. Ideal diodes optimize system energy efficiency through low conduction loss characteristics: a) Low forward voltage drop: The forward voltage drop when the MOSFET is on is ≤0.1V (calculated by RDS(on)×Iload, such as the voltage drop at IPT015N10N550A current≈1.5mΩ×50A≈0.075V), which is much lower than that of traditional Schottky diodes (0.5V~0.8V). A single ideal diode can reduce power consumption by more than 80%; b) No reverse leakage current: The reverse leakage current in the off state is ≤1μA, avoiding energy loss when the power supply is idle, especially suitable for the low power consumption requirements of eVTOL standby and other states; c) Heat dissipation advantage: The reduced heat caused by low power consumption means that the power distribution box does not need to be equipped with an additional heat sink for the ideal diode, further reducing the size and weight, meeting the requirements of lightweight onboard equipment.

[0039] In the specific implementation of this invention, the multi-level redundancy design includes primary redundancy, secondary redundancy and tertiary redundancy. Primary redundancy includes a high-voltage DC-DC power converter, a ground power supply and a low-voltage battery system. Secondary redundancy includes several groups of low-voltage batteries in the low-voltage battery system. Tertiary redundancy includes a first distribution bus and a second distribution bus.

[0040] Specifically, Level 1 redundancy (primary and backup power redundancy): The high-voltage DC-DC power converter, ground power supply, and low-voltage battery system constitute Level 1 redundancy. The primary power supply (high-voltage DC-DC power converter / ground power supply) is the priority power supply unit, and the low-voltage battery system is the backup power supply unit. Intelligent switching between primary and backup power supplies is achieved through ideal diodes.

[0041] Secondary redundancy (internal redundancy of backup power supply): Several groups of 48V low-voltage batteries in the low-voltage battery system constitute secondary redundancy. Through the dynamic voltage threshold control of ideal diodes, the power supply of multiple low-voltage batteries is coordinated in stages, ensuring voltage balance while realizing the internal redundancy of backup power supply.

[0042] Three-level redundancy (bus redundancy): Dual distribution buses (first and second distribution buses) constitute three-level redundancy. All power supply units supply power to both buses, achieving redundancy in the power distribution links and improving the system's fault tolerance. The three-level redundancy architecture—dual bus horizontal redundancy + main / backup power supply vertical redundancy + low-voltage battery internal redundancy—achieves full-dimensional redundancy in power supply units, power distribution links, and backup power supplies. Even in the event of a single power supply / bus / battery failure, the system can still supply power normally, significantly improving fault tolerance.

[0043] The output terminals of all power supply units are connected to the input terminals of dynamic threshold ideal diodes. The output terminals of the ideal diodes are connected to the first distribution bus and the second distribution bus respectively, according to the rule that one power supply corresponds to two buses. All the output terminals of the ideal diodes on each group of buses are connected in parallel to realize the combined switching of multiple power supplies on a single bus. The dual buses independently implement this topology logic, ultimately forming an intelligent switching topology of multiple power supplies - multiple ideal diodes - dual buses, realizing independent, accurate and fast switching of multiple power sources on dual buses.

[0044] Through the tiered collaborative power supply logic of the ideal diode, multiple low-voltage batteries achieve tiered power supply from single to multiple batteries based on a voltage difference threshold of 25mV. This ultimately keeps the voltage difference between all batteries within 25mV, preventing uneven power consumption and extending battery cycle life. When the main power supply voltage is higher than the low-voltage battery voltage, and the voltage difference exceeds 25mV, the ideal diode quickly turns off the MOSFET on the low-voltage battery side, completely stopping power supply to the low-voltage battery with no power consumption, ensuring the emergency backup power capability. The MOSFET of the ideal diode is a fully semiconductor device with no mechanical contacts, achieving a turn-off / turn-on response speed of 0.5μs. In the event of a main power failure, the low-voltage battery can instantly take over power, achieving seamless power switching and ensuring continuous and stable power supply to airborne electronic equipment. The core switching logic is implemented purely in hardware by the ideal diode, requiring no software intervention. This results in fast response speed, low failure probability, and suitability for the high reliability requirements of eVTOL airborne equipment.

[0045] In this embodiment of the invention, the dynamic threshold ideal diode includes a controller and a metal-oxide-semiconductor field-effect transistor. The controller has a built-in dynamic voltage threshold detection circuit, which can accurately identify the voltage difference between multiple power sources, achieve millivolt-level power supply decision-making, avoid the problem of low-potential power supply backflow to high-potential power source, and improve the accuracy of power switching. The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC power converter and a ground power supply. The backup power supply adopts a low-voltage battery system. The cooperation between the multi-source power supply unit and the dynamic threshold ideal diode enables zero-power switching between main and backup power supplies, ensuring backup capability. The high-voltage DC-DC power converter, ground power supply, and low-voltage battery system adopt a multi-level redundancy design. When a single power supply fails, the system can still supply power normally, greatly improving fault resistance. Through the cooperation of the dynamic threshold ideal diode, the multi-source power supply unit, and the dual power distribution bus, independent, accurate, and rapid switching of multiple power sources on the dual bus is achieved.

[0046] Example 2 Please see Figure 2 , Figure 2 This is a flowchart illustrating the intelligent switching method for multi-source redundant power supplies in an embodiment of the present invention. The intelligent switching method for multi-source redundant power supplies is implemented based on the aforementioned intelligent switching system for multi-source redundant power supplies, and the method includes: S11: The dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage. In a specific implementation of the present invention, the dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage, including: sampling the real-time voltage output by the multi-source power supply unit based on the IN and OUT pins of the controller in the dynamic threshold ideal diode; and calculating the voltage difference based on the real-time voltage using the dynamic voltage threshold detection circuit.

[0047] Specifically, the IN and OUT pins of the controller in the dynamic threshold ideal diode sample the real-time voltage output by the multi-source power supply unit. The IN and OUT pins of the LTC4357 core control chip used by the controller sample the voltage at the power supply terminal (input terminal) and the load terminal (output terminal / bus terminal) in real time, respectively. The voltage difference is calculated based on the real-time voltage using the dynamic voltage threshold detection circuit, that is, the voltage difference between IN and OUT is compared through the dynamic voltage threshold detection circuit.

[0048] S12: Compare the voltage difference with a preset threshold to obtain a comparison result, and trigger the shutdown logic of the multi-source power supply unit based on the comparison result; In a specific implementation of the present invention, the step of comparing the voltage difference with a preset threshold to obtain a comparison result, and triggering the shutdown logic of the multi-source power supply unit based on the comparison result, includes: if the voltage difference is greater than or equal to the preset threshold, then the multi-source power supply unit is determined to be in a normal conducting state, and no shutdown operation needs to be triggered; if the voltage difference is less than the preset threshold, then the multi-source power supply unit is determined to be in a reverse current state, and the shutdown operation of the multi-source power supply unit is triggered.

[0049] Specifically, if the voltage difference is greater than or equal to a preset threshold, the multi-source power supply unit is determined to be in a normal conducting state and no shutdown operation is required. The preset threshold can be set to 25mV. When the voltage difference is greater than 25mV, it is determined to be in a normal or conducting state.

[0050] If the voltage difference is less than a preset threshold, it is determined that the multi-source power supply unit is in a reverse current state, and the shutdown operation of the multi-source power supply unit is triggered. When the voltage difference is less than -25mV, it is determined that a reverse current has occurred, and the shutdown logic is triggered.

[0051] S13: Perform coil fault detection on the dual power distribution busbars and obtain the coil fault detection results; In a specific implementation of this invention, the step of performing coil fault detection on the dual power distribution busbars and obtaining coil fault detection results includes: performing coil disconnection detection on the dual power distribution busbars and obtaining coil disconnection detection results; performing coil voltage detection on the dual power distribution busbars and obtaining coil voltage information; performing overvoltage fault detection based on the coil voltage information and obtaining overvoltage fault detection results; and determining the coil fault detection results based on the coil disconnection detection results and the overvoltage fault detection results.

[0052] Specifically, coil disconnection detection is performed on the dual power distribution busbars to obtain the coil disconnection detection result, i.e., to detect whether the relays on the power distribution busbars have disconnected due to coil faults. Coil voltage detection is also performed on the dual power distribution busbars to obtain coil voltage information. Based on this coil voltage information, overvoltage fault detection is performed to obtain the overvoltage fault detection result. An overvoltage protection circuit based on the LTC4367 chip is connected in series in the relay coil power supply circuit. When the coil voltage exceeds 30V, it is determined to be an overvoltage fault. The coil fault detection result is determined based on the coil disconnection detection result and the overvoltage fault detection result; that is, the two detection results are combined, and if either detection result indicates a fault, it is determined to be a coil fault.

[0053] S14: Based on the coil fault detection results, perform fault isolation operation analysis to obtain fault isolation operation information, and perform seamless power switching based on the shutdown logic and fault isolation operation information.

[0054] In a specific implementation of this invention, the step of performing fault isolation operation analysis based on the coil fault detection results to obtain fault isolation operation information includes: determining the conduction priority and load current completion information of the dynamic threshold ideal diode based on the coil fault detection results, and determining first operation information based on the conduction priority and load current completion information; determining the cut-off operation information of the protection circuit and the current turn-off information of the dynamic threshold ideal diode based on the coil fault detection results, and determining second operation information based on the cut-off operation information and the current turn-off information; and determining fault isolation operation information based on the first operation information and the second operation information.

[0055] Specifically, based on the coil fault detection results, the conduction priority and load current completion information of the dynamic threshold ideal diode are determined, and the first operation information is determined based on the conduction priority and load current completion information. That is, when the relay of a certain bus is disconnected due to a coil fault, the ideal diode on the corresponding bus channel detects the current interruption and immediately triggers the ideal diode of another bus to increase the conduction priority and complete the load current within 0.5μs to ensure that the output voltage is uninterrupted.

[0056] Based on the coil fault detection results, the cut-off operation information of the protection circuit and the current turn-off information of the dynamic threshold ideal diode are determined. Based on the cut-off operation information and the current turn-off information, the second operation information is determined. That is, when the coil voltage is detected to be greater than 30V, the protection circuit cuts off the power supply, and the dynamic threshold ideal diode turns off the corresponding bus current at the same time to prevent the bus short circuit caused by the contactor sticking, thus forming a closed-loop protection of overvoltage-cut-off-isolation. Based on the first and second operation information, fault isolation operation information is determined. The combined operation of the two forms a dual-bus fault isolation. Seamless power switching is performed based on the shutdown logic and fault isolation operation information. At the same time, when the voltage difference between the two power supplies is less than or equal to 25mV, the LTC4357 chip controls the corresponding MOSFETs to remain on, and the current is distributed according to the voltage ratio (e.g., the 49V and 48V buses bear 52% and 48% of the load current, respectively), to avoid single power supply overload. When the voltage of a certain power supply fluctuates (e.g., the difference is >25mV due to the output change of the DC-DC module), the MOSFET on the low potential side is turned off within 0.5μs, while the high potential side remains on, and the output voltage fluctuation is ≤±0.5V, which meets the power supply stability requirements of avionics equipment such as eVTOL servos (allowable fluctuation ≤±1V) and flight controllers (allowable fluctuation ≤±0.3V).

[0057] In this embodiment of the invention, a dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference. The voltage difference is compared with a preset threshold, and the shutdown logic of the multi-source power supply unit is triggered based on the comparison result. Coil fault detection is performed on the dual power distribution bus to obtain the coil fault detection result. Based on the coil fault detection result, fault isolation operation analysis is performed to obtain fault isolation operation information. Based on the shutdown logic and fault isolation operation information, seamless power switching is performed, which improves the accuracy of voltage difference identification, realizes the coordination and redundancy of multiple power supplies, achieves seamless power switching, improves the accuracy of power switching, and ensures continuous and stable power supply for airborne electronic equipment.

[0058] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0059] Furthermore, the above provides a detailed description of the intelligent switching system and method for multi-source redundant power supplies provided by the embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-source redundant power supply intelligent switching system, characterized in that, The system includes: a dynamic threshold ideal diode, a multi-source power supply unit, a dual power distribution bus, and a protection circuit. The dynamic threshold ideal diode is connected to the dual power distribution bus, and the protection circuit is connected to both the dynamic threshold ideal diode and the multi-source power supply unit. The dynamic threshold ideal diode includes a controller and a metal-oxide-semiconductor field-effect transistor, the controller is connected to the metal-oxide-semiconductor field-effect transistor, and the controller has a built-in dynamic voltage threshold detection circuit. The multi-source power supply unit includes a main power supply and a backup power supply. The main power supply includes a high-voltage DC-DC power converter and a ground power supply. The backup power supply adopts a low-voltage battery system. The low-voltage battery system includes several groups of low-voltage batteries. The high-voltage DC-DC power converter, the ground power supply and the low-voltage battery system adopt a multi-level redundancy design. The dual power distribution bus includes a first power distribution bus and a second power distribution bus, and the first power distribution bus and the second power distribution bus are in a horizontal redundancy state. The protection circuit includes an overvoltage protection circuit, an electrostatic discharge protection circuit, and a transient voltage suppression circuit.

2. The intelligent switching system for multi-source redundant power supplies according to claim 1, characterized in that, The controller uses an LTC4357 core control chip, and the GATE pin of the LTC4357 core control chip is connected to the metal-oxide-semiconductor field-effect transistor.

3. The intelligent switching system for multi-source redundant power supplies according to claim 1, characterized in that, The metal-oxide-semiconductor field-effect transistor is an IPT015N10N5 metal-oxide-semiconductor field-effect transistor.

4. The intelligent switching system for multi-source redundant power supplies according to claim 1, characterized in that, The dynamic voltage threshold detection circuit includes a forward voltage drop comparator, a gate amplifier, and a charge pump.

5. The intelligent switching system for multi-source redundant power supplies according to claim 1, characterized in that, The multi-level redundancy design includes primary redundancy, secondary redundancy and tertiary redundancy. Primary redundancy includes a high-voltage DC-DC power converter, ground power supply and low-voltage battery system. Secondary redundancy includes several groups of low-voltage batteries in the low-voltage battery system. Tertiary redundancy includes a first distribution bus and a second distribution bus.

6. A method for intelligent switching of multi-source redundant power supplies, characterized in that, The intelligent switching method for multi-source redundant power supplies is implemented based on the intelligent switching system for multi-source redundant power supplies according to any one of claims 1 to 5, and the method includes: The dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage. The voltage difference is compared with a preset threshold to obtain a comparison result, and the shutdown logic of the multi-source power supply unit is triggered based on the comparison result. Coil fault detection was performed on the dual power distribution busbars, and the coil fault detection results were obtained. Based on the coil fault detection results, fault isolation operation analysis is performed to obtain fault isolation operation information, and seamless power switching is performed based on the shutdown logic and fault isolation operation information.

7. The intelligent switching method for multi-source redundant power supplies according to claim 6, characterized in that, The dynamic threshold ideal diode samples the real-time voltage output by the multi-source power supply unit and calculates the voltage difference of the real-time voltage, including: The real-time voltage output by the multi-source power supply unit is sampled by the IN and OUT pins of the controller in the dynamic threshold ideal diode. The voltage difference is calculated using the real-time voltage based on the dynamic voltage threshold detection circuit.

8. The intelligent switching method for multi-source redundant power supplies according to claim 6, characterized in that, The step of comparing the voltage difference with a preset threshold to obtain a comparison result, and triggering the shutdown logic of the multi-source power supply unit based on the comparison result, includes: If the voltage difference is greater than or equal to a preset threshold, the multi-source power supply unit is determined to be in a normal conducting state, and there is no need to trigger a shutdown operation. If the voltage difference is less than a preset threshold, it is determined that the multi-source power supply unit is in a reverse current state, triggering the shutdown operation of the multi-source power supply unit.

9. The intelligent switching method for multi-source redundant power supplies according to claim 6, characterized in that, The coil fault detection of the dual power distribution busbars, and the acquisition of coil fault detection results, include: Perform coil disconnection detection on the dual power distribution busbars and obtain the coil disconnection detection results; The coil voltage of the dual power distribution bus is detected to obtain coil voltage information. Overvoltage fault detection is performed based on the coil voltage information to obtain overvoltage fault detection results. The coil fault detection result is determined based on the coil disconnection detection result and the overvoltage fault detection result.

10. The intelligent switching method for multi-source redundant power supplies according to claim 6, characterized in that, The fault isolation operation analysis based on the coil fault detection results, to obtain fault isolation operation information, includes: Based on the coil fault detection results, the conduction priority and load current completion information of the dynamic threshold ideal diode are determined, and the first operation information is determined based on the conduction priority and load current completion information. Based on the coil fault detection results, the cut-off operation information of the protection circuit and the current turn-off information of the dynamic threshold ideal diode are determined, and the second operation information is determined based on the cut-off operation information and the current turn-off information. Fault isolation operation information is determined based on the first operation information and the second operation information.

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