A master-slave power switching power management device with anti-reflux function

Abstract

The application provides a main and standby power switching power management device with anti-backflow function, which comprises a one-key switch power-on and power-off circuit, a counter electromotive force absorption and detection circuit, an anti-backflow board power supply circuit, a battery voltage acquisition circuit, an MCU minimum system and CAN isolation circuit and a standby battery discharge circuit; the output end of the one-key switch power-on and power-off circuit is connected with the input end of the anti-backflow board power supply circuit; the output end of the anti-backflow board power supply circuit is respectively connected with the power input end of the battery voltage acquisition circuit, the MCU minimum system and CAN isolation circuit and the standby battery discharge circuit; the output end of the anti-backflow board power supply circuit is also connected with the monitoring input end of the counter electromotive force absorption and detection circuit; and the control signal output end of the MCU minimum system and CAN isolation circuit is connected with the control input end of the standby battery discharge circuit. The application constructs a highly integrated power management device, and ensures the orderliness and stability of the whole system power supply.

Description

Technical Field

[0001] This invention relates to the field of tethered unmanned aerial vehicle (UAV) technology, specifically to a power management system for tethered UAVs, and particularly to a power management device for switching between main and backup power with one-button power-on / off, automatic switching between main and backup power, back EMF absorption, and anti-backflow function. Background Technology

[0002] Tethered drones receive a continuous power supply from the ground grid via a tether, enabling them to operate for hours or even days. They have wide applications in communication relay, aerial surveillance, and emergency rescue. Their onboard power systems typically employ a dual-architecture design: the main power system receives power directly from the ground via the tether, which is then converted by the onboard power supply to provide long-duration, high-power support for the flight platform and various mission payloads; the backup power system, mostly composed of onboard lithium battery packs, provides emergency power to the flight control system and power unit in the event of a main power outage, ensuring a safe emergency landing and avoiding the risk of a crash. Furthermore, drone motors generate instantaneous high-voltage back electromotive force during speed adjustment or braking. If this back electromotive force is not promptly discharged and absorbed, it can impact or even damage sensitive electronic equipment within the main power system. Therefore, the backup power system also needs to absorb this back electromotive force.

[0003] Currently, most common backup power system integration solutions directly connect backup batteries in parallel to the main power bus. While this architecture is simple, it presents significant safety hazards and performance bottlenecks. Specifically, if the backup battery is not equipped with a Battery Management System (BMS), its charging circuit is completely uncontrollable. When the main power is operating normally, the bus voltage continuously float-charges the battery, which can easily lead to overcharging of the lithium battery, causing serious safety accidents such as bulging, thermal runaway, or even fire and explosion. To mitigate this risk, some designs use smart lithium batteries with built-in BMS. Although these batteries can prevent overcharging and over-discharging through internal protection circuits, they are designed to meet the medium power requirements of consumer electronics or power tools. The MOSFETs and inductors in the discharge circuit usually cannot withstand the large current required for a short period of time during a tethered drone's emergency landing, thus failing to output sufficient power effectively in emergencies, causing the backup power function to fail.

[0004] In summary, existing technologies face a dilemma between overcharging and insufficient discharge capacity: BMS-less battery solutions are low-cost but unsafe, while BMS-equipped battery solutions are relatively safe but their discharge capacity cannot meet requirements. This fundamental contradiction poses a serious challenge to the reliability of tethered drone power systems. Therefore, there is an urgent need in this field for an innovative power management solution that can intelligently manage the charging process of backup batteries without sacrificing safety, while ensuring that its discharge circuit has rapid response and high-power output capabilities, thereby comprehensively improving the redundancy reliability and flight safety of tethered drone power systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a power management device for switching between primary and backup power for tethered unmanned aerial vehicles (UAVs). This device can effectively prevent the backup battery from being overcharged, while meeting the requirements of high-power discharge, and integrates functions such as one-button power-on / off, automatic switching between primary and backup power, and back electromotive force absorption and statistics.

[0006] The present invention provides a main and backup power switching power management device with anti-backflow function, comprising: a one-button power-on / off circuit, a back electromotive force absorption and detection circuit, an anti-backflow board power circuit, a battery voltage acquisition circuit, an MCU minimum system and CAN isolation circuit, and a backup battery discharge circuit.

[0007] The output terminal of the one-button switch power-on / off circuit is connected to the input terminal of the anti-backflow board power circuit, and is used to receive the trigger signal of the external mechanical switch or airborne power supply, and to provide initial power enable for the entire device.

[0008] The anti-backflow plate power supply circuit serves as the power distribution and management hub of the device. Its output terminal is connected to the power input terminal of the battery voltage acquisition circuit, the MCU minimum system and CAN isolation circuit, and the backup battery discharge circuit, respectively, to provide them with a stable operating voltage. At the same time, the output terminal of the anti-backflow plate power supply circuit is also connected to the monitoring input terminal of the back electromotive force absorption and detection circuit.

[0009] The signal output terminals of the battery voltage acquisition circuit, the back EMF absorption and detection circuit, and the status signal output terminal of the backup battery discharge circuit are all connected to the corresponding input ports of the MCU minimum system and the CAN isolation circuit.

[0010] The control signal output terminal of the MCU minimum system and CAN isolation circuit is connected to the control input terminal of the backup battery discharge circuit to send on / off commands;

[0011] The backup battery discharge circuit is connected in series between the backup battery and the airborne power bus, and is controlled by the MCU minimum system and the CAN isolation circuit. It is used to realize the controllable connection and disconnection of the backup battery discharge circuit. It should be noted that the backup battery and the airborne power supply here are composed of two parts. The backup battery is a set of power supply devices, and the airborne power supply is a set of power supply devices. Usually, one of them is selected as the power supply, but in special circumstances, they can also supply power simultaneously. In this invention, the two sets of power supplies are described together, but those skilled in the art can clearly understand the structure of the two parts and the methods and uses of each.

[0012] This invention constructs a highly integrated power management device by defining the connection relationships of six core circuits, including the one-button power-on / off circuit, the anti-backflow power supply circuit, the MCU minimum system, and the CAN isolation circuit. It clarifies the collaborative working architecture between the various functional modules, and in particular establishes the core position of the anti-backflow power supply circuit as the power distribution and management hub, thereby ensuring the orderliness and stability of the power supply of the entire system and laying a solid hardware foundation for the subsequent realization of complex power management functions.

[0013] Based on the optimized design of the aforementioned device, the one-button power-on / off circuit is configured to manage the power supply of the entire device and its downstream loads, and to implement two power-on modes and one power-off process:

[0014] Power-on mode 1: When the onboard power supply is not turned on, operating the mechanical switch can directly trigger the one-button power-on / off circuit, powering the entire system on and supplying power from the backup battery.

[0015] Power-on mode 2: When the airborne power supply is turned on first, the one-button switch power-on / off circuit is automatically powered on and enables the entire system to be powered by the airborne power supply.

[0016] Power-down procedure: First, the onboard power must be turned off. Then, by pressing and holding the mechanical switch or receiving a remote power-down command from the MCU minimum system and CAN isolation circuit, the internal soft switch is opened, thus powering down the entire system. This provides a flexible and safe system start-up and shutdown control mechanism. Users can choose different power-up methods according to actual conditions, and the operation is simple. The power-down procedure requires turning off the main power before sending the command, effectively avoiding the risks of arcing and misoperation, ensuring the safety and reliability of the system power-down process, and improving the overall operational safety of the device.

[0017] Based on the optimized design of the above device, the back EMF absorption and detection circuit includes a voltage comparator, a gate driver, and an absorption circuit switch.

[0018] The voltage comparator is configured to monitor the onboard power bus voltage in real time and compare the bus voltage with a preset voltage threshold.

[0019] The gate driver, whose input is connected to the output of the voltage comparator, is configured to drive the absorption circuit switch to turn on when the bus voltage exceeds the preset voltage threshold.

[0020] After the absorption circuit switch is turned on, an energy absorption circuit is formed from the airborne power bus to the backup battery. This enables automatic and rapid detection and absorption of harmful back electromotive force voltage generated by the motor. Through the cooperation of the voltage comparator and the gate driver, it can quickly act when the voltage exceeds the threshold, discharging the back electromotive force energy to the backup battery, thereby effectively protecting the airborne power system from high-voltage impacts and improving the system's reliability.

[0021] Based on the optimized design of the aforementioned device, a diode is connected in series in the energy absorption circuit. This diode is configured to ensure that the absorption current can flow unidirectionally from the onboard power bus to the backup battery, preventing reverse energy flow. This design ensures that energy can only flow unidirectionally from the onboard bus to the backup battery, strictly preventing the backup battery's energy from flowing back into the bus in a non-absorption state. This avoids unnecessary energy loss and circuit interference, enhancing the accuracy and safety of the absorption circuit.

[0022] Based on the optimized design of the aforementioned device, the MCU minimum system and CAN isolation circuit are connected to the output of the gate driver and configured to count the drive signals generated by the gate driver, thereby counting the number of back EMF events. This upgrades the simple protection function to an intelligent function with condition monitoring. By counting the number of events, valuable data support can be provided for health status assessment of the UAV system, workload analysis of the motor drive system, and predictive maintenance, increasing the added value of the device.

[0023] Based on the optimized design of the above device, the backup battery discharge circuit includes a controllable switching unit and an ideal diode unit;

[0024] The controllable switch unit is connected in series in the airborne power bus and is controlled by the MCU minimum system and CAN isolation circuit to actively connect or disconnect the discharge circuit of the backup battery.

[0025] The ideal diode unit, connected between the backup battery and the controllable switch unit, consists of an ORing controller and a MOSFET. The ORing controller automatically controls the switching of the MOSFET by detecting the voltage difference at its input terminal, thereby achieving unidirectional current flow from the backup battery to the onboard power bus and preventing reverse current from flowing into the battery. This solution resolves the contradiction between "overcharging" and "high-power discharge" of the backup battery. The controllable switch unit achieves active management of the discharge circuit, while the ideal diode unit uses the ORing controller to achieve automatic control of unidirectional current flow, fundamentally preventing reverse charging of the backup battery by the main power supply, while ensuring the high-power discharge capability required during forced landing.

[0026] Based on the optimized design of the aforementioned device, the MOSFETs in the controllable switching unit and the ideal diode unit are both selected to withstand a continuous conduction current of no less than 400A. This concretizes and measures the core performance indicator of high-power discharge, ensuring that the device can effectively meet the extreme power requirements of tethered UAVs under emergency landing conditions, thereby guaranteeing the flight safety of the UAV.

[0027] Based on the optimized design of the aforementioned device, the backup battery discharge circuit further includes a status detection unit. This status detection unit generates a level signal indicating the on / off state of the discharge circuit based on the drive signal output by the ORing controller, and feeds it back to the MCU minimum system and the CAN isolation circuit. This invention enables the MCU to obtain information on whether the backup battery is discharging in real time and accurately. This achieves transparent monitoring of the power supply status, facilitating intelligent decision-making and fault diagnosis. Furthermore, it provides key status parameters for remote monitoring by the ground station, improving system maintainability.

[0028] This invention also introduces a control method based on the above-mentioned main / standby power switching management device with anti-backflow function, comprising:

[0029] System power-on procedure: Check the onboard power status; if the onboard power is not turned on, the system is powered on by triggering a mechanical switch and powered by the backup battery; if the onboard power is turned on, the system is automatically powered on and powered by the onboard power.

[0030] Real-time monitoring and absorption steps: The bus voltage is continuously monitored through the back EMF absorption and detection circuit. When back EMF is detected, energy is automatically absorbed, and the MCU minimum system and CAN isolation circuit count the events. Simultaneously, the backup battery voltage is monitored through the battery voltage acquisition circuit. Main and backup power switching and status monitoring steps: When the main power is normal, the MCU minimum system and CAN isolation circuit control the backup battery discharge circuit to shut down. When a main power failure causes the bus voltage to drop, the backup battery discharge circuit automatically turns on to achieve power switching and feeds back the discharge status signal to the MCU. System power-down steps: First, the onboard power is turned off, and then the system power output is cut off by the MCU through long-pressing the mechanical switch or receiving a remote power-down command, completing the power-down process. This method transforms the hardware advantages of the device into a clear and executable intelligent management process. This method covers the entire process of power-on, real-time monitoring, absorption, switching, status monitoring, and power-down, realizing the automation and intelligence of power management and ensuring the power safety of the tethered UAV under different operating conditions.

[0031] To further optimize the above control method, a temperature protection process is also included in the real-time monitoring and absorption step and the main / backup power switching and status monitoring step:

[0032] The MCU minimum system and CAN isolation circuit collect the temperature of the power MOSFET in the backup battery discharge circuit in real time through a temperature sensor.

[0033] When the temperature exceeds the first preset safety threshold, the MCU minimum system and CAN isolation circuit issue an overheat warning;

[0034] When the temperature exceeds a higher second preset safety threshold, the MCU minimum system and CAN isolation circuit directly control the controllable switching unit in the backup battery discharge circuit to shut down, thereby implementing overheat protection. This invention provides an active safety protection mechanism for the system. Through two levels of protection—early warning and forced shutdown—it effectively prevents overheating damage to the power MOSFETs caused by overcurrent or environmental factors, improving the system's robustness and reliability under harsh operating conditions and avoiding system failures caused by overheating.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. This invention fundamentally resolves the contradiction between "overcharging" and "high-power discharging" of backup batteries, significantly improving safety and reliability. Through an "ideal diode" circuit composed of a controller and a MOSFET, the invention achieves automatic, unidirectional conduction of the backup battery discharge circuit at the hardware level. This design completely eliminates reverse current from the main power system to the backup battery, eliminating the need for the battery's own BMS and thus removing the risk of overcharging at its source, greatly improving system safety. Simultaneously, the discharge circuit uses specially selected high-current, low-internal-resistance power MOSFETs, easily handling continuous currents exceeding 400A, perfectly meeting the high-power discharge requirements of tethered drones during emergency landings. Therefore, it achieves a balance between safety and high power in its core performance.

[0037] 2. This invention achieves fully intelligent management and lossless standby of the backup power system's operating status, extending system lifespan. It doesn't simply connect the backup battery in parallel to the bus; instead, it precisely manages the backup battery's status through the collaboration of the MCU and intelligent circuits. When the main power supply is operating normally, the backup battery circuit is physically disconnected, placing it in a true "zero-power consumption" hot standby state. This not only saves energy but also avoids unnecessary charge-discharge cycles, effectively extending battery life. When the main power supply fails, the system can automatically switch over within milliseconds based on voltage comparison, without flight control intervention, demonstrating extremely fast response and high reliability. Furthermore, functions such as active absorption and counting of back EMF events and real-time monitoring of MOSFET temperature demonstrate the system's refined and intelligent management.

[0038] 3. This invention achieves a high degree of integration of multiple functions, optimizes the system architecture, and brings significant added value. It integrates functions such as one-click power-on / off management, automatic switching between main and backup power, back EMF absorption, status monitoring, and CAN communication into a single "anti-backflow board," simplifying the power wiring design of the entire tethered UAV and improving system integration and reliability. Users can conveniently control the entire aircraft power system through mechanical switches or ground station commands, enhancing the user experience. At the same time, the uploading of data such as the statistics of back EMF absorption times, battery voltage, and MOS temperature provides valuable data support for ground personnel to assess the system's health status and perform predictive maintenance, adding significant added value. Attached Figure Description

[0039] Figure 1 This is a system structure block diagram of the main / standby power switching power management device with anti-backflow function of the present invention;

[0040] Figure 2 This is a flowchart of the instruction for the one-button switch power-on / off circuit in this invention.

[0041] Figure 3 This is a schematic diagram of the back electromotive force absorption and detection circuit in this invention;

[0042] Figure 4 This is a schematic diagram of the power supply circuit for the anti-backflow plate in this invention.

[0043] In the diagram, 1—one-button power-on / off circuit, 2—back EMF absorption and detection circuit, 3—anti-reverse backflow protection power supply circuit, 4—battery voltage acquisition circuit, 5—MCU minimum system and CAN isolation circuit, 6—backup battery discharge circuit, and 7—backup battery and onboard power supply. Detailed Implementation

[0044] The present invention will now be further described with reference to the accompanying drawings.

[0045] like Figures 1-4 As shown, this invention provides a highly integrated, intelligent, and reliable main / backup power switching management device with anti-backflow function. The core design idea of ​​this device is to systematically solve problems such as overcharging risk, high-power discharge requirements, back EMF impact, and system power-on / off management of backup batteries in tethered UAV systems through innovative hardware circuit design and precise logic control.

[0046] The overall architecture of this invention is built around the power distribution and management hub of the anti-backflow plate power circuit. The various functional modules form a complete power management closed loop through clear electrical connections and signal interactions.

[0047] The one-button power-on / off circuit 1 acts as the "master switch" of the entire device, responsible for receiving trigger signals from external mechanical switches or onboard power supplies. It supports two power-on logics: regardless of whether the onboard power supply is turned on before the mechanical switch, the circuit can intelligently complete the system startup initialization and provide stable initial power supply enable for subsequent circuits, ensuring the flexibility and reliability of system startup.

[0048] The anti-backflow power supply circuit 2 is the "heart" of this device. It receives electrical energy from upstream, converts and distributes it, providing accurate and stable operating voltages for key downstream modules such as the battery voltage acquisition circuit 4, the MCU minimum system and CAN isolation circuit 5, and the backup battery discharge circuit 6. The output of the anti-backflow power supply circuit 2 is also directly connected to the monitoring point of the back EMF absorption and detection circuit, providing a voltage reference for back EMF detection. This centralized power supply architecture simplifies system design and improves power quality.

[0049] The MCU minimum system and CAN isolation circuit 5 is the "intelligent hub" of the device. It integrates the microcontroller (MCU) and its necessary peripheral circuits, as well as a CAN bus interface with isolation function. The MCU minimum system and CAN isolation circuit 5 are responsible for collecting signals from various sensors (such as battery voltage, discharge state, back EMF events, MOSFET temperature), executing the core control algorithm, and communicating in real time with the UAV flight controller or ground station via the CAN bus to realize status uploading and command reception.

[0050] The backup battery discharge circuit 6 is the core actuator for realizing the functions of "anti-reverse charging" and "main / backup power switching". It is connected in series between the backup battery and the onboard power bus, and its internal design adopts a composite design of "controllable switching unit + ideal diode unit". The controllable switching unit (such as a MOSFET controlled by the MCU) gives the MCU the power to actively turn on or off the entire discharge circuit, realizing the "controllability" of discharge. The ideal diode unit (composed of an ORing controller and a MOSFET) uses hardware to automatically compare voltages to realize the "one-way conduction" of current from the battery to the bus, completely eliminating the reverse charging (i.e., "reverse charging") from the main power to the battery, realizing "one-way". The backup battery discharge circuit 6 also integrates a status detection unit, which can feed back the actual status (on / off) of the discharge circuit to the MCU in real time, realizing visual status management.

[0051] The back EMF absorption and detection circuit 2 is an independent, fast-response protection channel. It monitors the bus voltage in real time via a voltage comparator. Once it detects a back EMF generated by the motor causing an abnormal voltage rise, it quickly activates, directing the high-voltage energy to the backup battery for absorption, thus protecting the main power system. Simultaneously, it can send the absorption event signal to the MCU for counting, providing data for system health diagnosis.

[0052] The battery voltage acquisition circuit 4 is responsible for monitoring the voltage of the backup battery in real time, which is an important basis for the MCU to judge the battery's state of charge (SOC) and state of health (SOH).

[0053] The one-button power-on / off circuit 1 is a key interface circuit for realizing intelligent start-stop of the system, and its core lies in the integration of a "soft switch" mechanism. The one-button power-on / off circuit 1 includes a mechanical self-reset switch, a debounce circuit, a level detection circuit, an electronic switch controlled by an MCU (such as a MOSFET or a dedicated power management IC), and necessary drive circuits.

[0054] Power-on Mode 1: When the tethered cable is not connected or the ground power is not turned on, the airborne power supply is in an inactive state. When the user presses the mechanical switch, the action is captured by the level detection circuit, generating a wake-up signal. This signal provides the initial operating voltage to the MCU minimum system directly or through an initial power module. After the MCU is powered on and initialized, it immediately outputs a high level (or PWM signal) through its I / O port, driving the electronic switch (soft switch) to remain closed. At this point, the power from the backup battery is supplied to the anti-backflow power circuit through this closed switch, thereby powering the entire system. In this situation, the aircraft is entirely powered by the backup battery.

[0055] Power-on mode two: When the tethered cable is connected and the ground power supply is normal, the airborne power supply is established first. The airborne power supply voltage is directly applied to the one-button power-on / off circuit, causing its internal initial power module to work, which then supplies power to the MCU minimum system. After the MCU initializes, it also controls the internal electronic switch to close. Since the airborne power supply is already present and its voltage is usually higher than the backup battery voltage, the entire system's power will be mainly supplied by the airborne power supply, and the backup battery will be in standby mode.

[0056] The power-down process is a safe and orderly procedure. First, the onboard power supply must be disconnected (e.g., by unplugging the mooring cable). This operation switches the main power supply to the backup battery. Then, the user presses and holds the mechanical switch (for more than 3 seconds) or sends a power-down command via ground station software. After the MCU detects the long press signal or receives the command via the CAN bus, it performs a series of safety checks (e.g., confirming that the motor has stopped). Finally, it invalidates the drive signal of the electronic switch it controls, causing the electronic switch to open, thus completely cutting off the power to all circuits and completing the safe power-down. This two-step method of "disconnecting the main power first, then sending the command" effectively prevents the risks of hot-plugging and accidental triggering.

[0057] The back EMF absorption and detection circuit 2 is a high-speed, automatic voltage clamping protection system. It employs a precision voltage comparator chip (such as an LM393), with its non-inverting input connected to the airborne power bus and sampled via a resistor divider network. Its inverting input is connected to a stable reference voltage source (such as a reference provided by a TL431), set to a threshold voltage slightly higher than the highest voltage during normal operation of the airborne power supply (e.g., if the normal bus voltage is 50V, the threshold can be set to 52V). The comparator chip's output is connected to the input of a gate driver (such as a TC4427). When the bus voltage exceeds the threshold due to a back EMF surge, the comparator output flips to a high level, rapidly activating the gate driver and using its powerful driving capability to turn on a high-power MOSFET (sucking loop switch). The MOSFET, a unidirectional diode, and a backup battery together form an absorption circuit. The diode is connected in series between the MOSFET and the positive terminal of the backup battery, with its direction forward biased towards the battery. When the MOSFET is turned on, the high-voltage pulse current on the bus can only flow to the backup battery through the diode, charging the battery and thus absorbing the energy. The key function of the diode is to prevent the battery current from flowing back to the bus when the bus voltage returns to normal or falls below the battery voltage. The output signal of the gate driver (a high-voltage pulse) is simultaneously fed to a GPIO port or a counter input port of the MCU. The MCU detects the rising or falling edge of this signal through programming. Each time it is detected, the internal counter increments by one. This count value can be sent to the ground station via the CAN bus to evaluate the working intensity of the motor drive system and analyze the frequency of back electromotive force.

[0058] The backup battery discharge circuit 6 is the hardware core of the anti-backflow and automatic main / backup power switching functions of this invention. The backup battery discharge circuit 6 includes a controllable switch unit and an ideal diode unit. The controllable switch unit consists of a high-current MOSFET (Q_master) directly controlled by the MCU, connected in series in the main power supply circuit of the system. The MCU sends a DRV_MASTER signal to the gate of this MOSFET through a dedicated gate driver chip. When the signal is high, Q_master is turned on, and the main circuit is unobstructed; when the signal is low, Q_master is turned off, and even if the ideal diode unit is turned on, the battery cannot discharge. This gives the MCU the highest level of discharge control, which can be used for emergency shutdown or system power-off.

[0059] The ideal diode unit here is key to achieving "automatic switching and prevention of reverse current". The ideal diode unit includes an ORing controller, which is a dedicated chip (such as LTC4359) that continuously monitors the voltage of two sense pins of the MOSFET (named SENSEA and SENSEB), which are connected to the backup battery terminal and the onboard power bus terminal, respectively.

[0060] The reverse charging prevention principle in this invention is as follows: The ORing controller internally compares and detects the voltage at the pins of the MOSFET. When the voltage at point SENSEB (bus voltage) is higher than the voltage at point SENSEA (battery voltage), it indicates that the main power supply is normal. The controller outputs a low level, turning off the MOSFET it drives, thereby cutting off the path from the battery to the bus and preventing the main power supply from recharging the battery. When the main power fails and the voltage at point SENSEB drops below the voltage at point SENSEA, the ORing controller quickly outputs a high-level drive signal, fully turning on the MOSFET, allowing the backup battery to discharge to the bus.

[0061] The backup battery discharge circuit 6 in this invention has a high current capability guarantee function: to ensure sufficient power during a forced landing, both the controllable switching unit and the ideal diode unit must use power MOSFETs with low internal resistance and high continuous current rating (specifically required to be no less than 400A). Their packaging must consider heat dissipation, such as using TO-247 or more advanced low thermal resistance packages, and mounting them on a heat sink. The backup battery discharge circuit 6 also includes a status detection unit: this unit is a simple level conversion or signal isolation circuit that receives the drive signal output from the ORing controller. When the MOSFET is driven to conduct (i.e., the battery is discharging), the output is high. The status detection circuit correspondingly outputs a high-level signal to the MCU. The MCU can read this signal to determine in real time and accurately whether the backup battery is in a discharging state, achieving transparent monitoring of the power supply status.

[0062] Working principle of the device of the present invention:

[0063] The overall workflow of the device of this invention can be divided into four main stages: system power-on, normal operation and monitoring, automatic switching between main and backup power, and system power-off.

[0064] I. System Power-On Phase:

[0065] The device supports two power-on paths to adapt to different startup scenarios:

[0066] Backup power priority: When the drone is not connected to the tether cable (onboard power is invalid), the user operates the mechanical switch, triggering the one-button power-on / off circuit, which first powers the MCU minimum system. After MCU initialization, it immediately controls its internal "soft switch" to close, drawing power from the backup battery to the anti-backflow board power circuit. This circuit then provides stable voltage to modules such as the battery voltage acquisition circuit and the backup battery discharge circuit, completing the system startup, at which point the backup battery powers the system.

[0067] Main power priority: When the mooring cable is connected (airborne power is effective), the airborne power directly enables the one-button switch power-on / off circuit and the anti-backflow board power circuit, and the system automatically powers on; after the MCU starts, it also closes the soft switch, but because the airborne power voltage is present and higher, the system is powered by the airborne power.

[0068] II. Normal Operation and Monitoring Phase: Real-time Protection and Status Tracking

[0069] After the system is powered on, each module enters real-time operating mode:

[0070] Main power supply, backup power standby: When the onboard power supply is working normally, the "ideal diode unit" in the backup battery discharge circuit is automatically turned off because the onboard power bus voltage is higher than the battery voltage; at this time, the backup battery is physically isolated from the bus and is in a "zero power consumption" hot standby state, which fundamentally avoids the risk of overcharging.

[0071] Active back EMF absorption: The back EMF absorption and detection circuit continuously monitors the bus voltage. When the drone motor generates a momentary high voltage (back EMF) during speed adjustment or braking, the bus voltage surges. Once it exceeds a preset threshold, the circuit's voltage comparator immediately flips, rapidly opening the absorption circuit switch via the gate driver, and discharging the energy into the backup battery through a unidirectional diode. This process is an automatic hardware response, extremely fast, effectively protecting sensitive airborne electronic equipment. Simultaneously, the MCU counts the absorption events, providing data for system health diagnostics.

[0072] Comprehensive status monitoring: The MCU minimum system continuously collects battery voltage data from the battery voltage acquisition circuit, discharge status signals (which should be in "non-discharge state") fed back by the status detection unit in the backup battery discharge circuit, and temperature data of the power MOSFETs. All of this information can be uploaded to the ground station via a CAN isolation circuit, enabling transparent monitoring of the power system.

[0073] III. Automatic Switching Phase between Main and Backup Power: Seamless Connection and High-Power Discharge

[0074] When the main power system (airborne power supply) fails (such as a broken mooring or a ground power outage):

[0075] Voltage Detection and Automatic Turn-On: When the onboard power bus voltage drops rapidly, the ORing controller of the "ideal diode unit" in the backup battery discharge circuit detects in real time that the bus voltage is lower than the battery voltage and automatically outputs a drive signal within milliseconds to fully turn on the MOSFET it controls.

[0076] Discharge path established: At this point, the discharge path from the backup battery to the bus has been established. Since the controllable switch unit remains open during normal operation, the power from the backup battery can be injected into the bus immediately and seamlessly to power the flight control system and the power system, ensuring the UAV can make an emergency landing.

[0077] Status Reporting and Maintenance: The status detection unit immediately detects the discharge circuit is active and sends a "discharging" status signal to the MCU. The MCU is aware that it has entered backup power supply mode and can send an alarm to the flight controller via the CAN bus. The entire discharge circuit uses a power MOSFET capable of withstanding currents of over 400A to ensure that the high power requirements during a forced landing are met.

[0078] IV. System Power-Down Phase: Safe and Orderly Shutdown Procedure

[0079] First requirement: The onboard power must be disconnected (e.g., the mooring cable must be removed) to switch the system to a state powered by the backup battery.

[0080] Sending commands: Users can send remote power-off commands by pressing and holding the mechanical switch or the ground station.

[0081] MCU safety logic execution: After receiving the instruction, the MCU first performs a safety check (such as checking the motor status), and then controls the controllable switch unit in the backup battery discharge circuit to turn off, cutting off the main discharge circuit.

[0082] Complete power off: Finally, the "soft switch" in the MCU-controlled one-button power-on / off circuit is turned off, completely cutting off the power supply to the entire device and completing the power-off process.

[0083] The real-time monitoring and absorption step and the main / backup power switching and status monitoring step also include a temperature protection process: the MCU minimum system and CAN isolation circuit 5 collect the temperature of the power MOSFET in the backup battery discharge circuit 6 in real time through a temperature sensor; when the temperature exceeds a first preset safety threshold, the MCU minimum system and CAN isolation circuit 5 issue an overheat warning; when the temperature exceeds a higher second preset safety threshold, the MCU minimum system and CAN isolation circuit 5 directly control the controllable switching unit in the backup battery discharge circuit 6 to turn off, so as to implement overheat protection.

[0084] This invention provides a highly integrated and intelligent power management device and method for switching between main and backup power for tethered unmanned aerial vehicles (UAVs). It aims to systematically address core pain points in traditional solutions, such as the ease of overcharging backup batteries, insufficient high-power discharge capacity, back EMF impact threats, and inconvenient power-on / off management. The device achieves superior performance and reliability through innovative hardware circuit design and precise algorithm control. Its core innovation lies in constructing a collaborative system with an MCU as the intelligent control center and an anti-reverse charging board power circuit as the power hub. The critical backup battery discharge circuit adopts a composite architecture of "controllable switching unit" and "ideal diode unit," utilizing an ORing controller to achieve automatic unidirectional current conduction, fundamentally eliminating reverse charging of the backup battery by the main power source. Simultaneously, the use of high-current MOSFETs ensures emergency discharge requirements exceeding 400A, perfectly resolving the contradiction between safety and power performance. The integrated back EMF absorption and detection circuit provides an independent hardware-level fast protection channel, which can actively absorb harmful voltage spikes generated by the motor and record the number of events. The intelligent one-button power-on / off circuit defines a flexible and safe system start-up and shutdown process, while the graded temperature protection mechanism ensures the safety of power devices under extreme operating conditions through a dual strategy of early warning and forced shutdown.

[0085] In summary, this invention, through the precise coordination of various functional modules, achieves "idle-time isolated standby and emergency-time instantaneous switching" of backup batteries. It not only provides powerful basic power management functions, but also endows the system with advanced intelligent capabilities such as system status monitoring, fault early warning and active protection, significantly improving the safety, reliability and maintainability of the tethered UAV power system.

[0086] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Although the applicant has described the present invention in detail with reference to preferred embodiments, those skilled in the art should understand that any modifications or equivalent substitutions made to the technical solutions of the present invention cannot depart from the spirit and scope of the present invention and should be covered within the scope of the claims of the present invention.

Claims

1. A main / standby power switching management device with anti-backflow function, characterized in that, include: The device comprises a one-button power-on / off circuit (1), a back EMF absorption and detection circuit (2), an anti-reverse filling plate power supply circuit (3), a battery voltage acquisition circuit (4), an MCU minimum system and CAN isolation circuit (5), and a backup battery discharge circuit (6). The output of the one-button power-on / off circuit (1) is connected to the input of the anti-reverse filling plate power supply circuit (3) to receive trigger signals from external mechanical switches or onboard power supplies and to provide initial power enable for the entire device. The anti-reverse filling plate power supply circuit (3) serves as the power distribution and management hub of the device. Its output is connected to the power input of the battery voltage acquisition circuit (4), the MCU minimum system and CAN isolation circuit (5), and the backup battery discharge circuit (6) to provide them with a stable operating voltage. At the same time, the anti-reverse filling plate power supply... The output of circuit (3) is also connected to the monitoring input of the back EMF absorption and detection circuit (2); the signal output of the battery voltage acquisition circuit (4), the signal output of the back EMF absorption and detection circuit (2), and the status signal output of the backup battery discharge circuit (6) are all connected to the corresponding input ports of the MCU minimum system and CAN isolation circuit (5); the control signal output of the MCU minimum system and CAN isolation circuit (5) is connected to the control input of the backup battery discharge circuit (6) to send on / off commands; the backup battery discharge circuit (6) is connected in series between the backup battery and the onboard power supply bus, and is controlled by the MCU minimum system and CAN isolation circuit (5) to realize the controllable connection and disconnection of the backup battery discharge circuit.

2. The main / standby power switching management device with anti-backflow function according to claim 1, characterized in that, The one-button power-on / off circuit (1) is configured to manage the power supply of the entire device and the downstream load, and realize two power-on modes and one power-off process: Power-on mode 1: When the onboard power supply is not turned on, the operation of the mechanical switch can directly trigger the one-button power-on / off circuit (1) to power on the entire system and be powered by the backup battery; Power-on mode 2: When the onboard power supply is turned on first, the one-button power-on / off circuit (1) is automatically powered on and enables the entire system to be powered on and powered by the onboard power supply; Power-off process: The onboard power supply must be turned off first, and then the internal soft switch is turned off by long-pressing the mechanical switch or by receiving the remote power-off command from the MCU minimum system and CAN isolation circuit (5), thereby realizing the power-off of the entire system.

3. The main / standby power switching management device with anti-backflow function according to claim 1, characterized in that, The back EMF absorption and detection circuit (2) includes a voltage comparator, a gate driver, and an absorption loop switch; the voltage comparator is configured to monitor the onboard power bus voltage in real time and compare the bus voltage with a preset voltage threshold. The gate driver, whose input is connected to the output of the voltage comparator, is configured to drive the absorption circuit switch to turn on when the bus voltage exceeds the preset voltage threshold; after the absorption circuit switch is turned on, an energy absorption circuit is formed from the airborne power bus to the backup battery.

4. The main / standby power switching management device with anti-backflow function according to claim 3, characterized in that, A diode is connected in series in the energy absorption circuit. The diode is configured to ensure that the absorption current can only flow unidirectionally from the airborne power bus to the backup battery, preventing energy from flowing in the opposite direction.

5. The main / standby power switching management device with anti-backflow function according to claim 3 or 4, characterized in that, The MCU minimum system and CAN isolation circuit (5) are connected to the output terminal of the gate driver and configured to count the drive signals generated by the gate driver, thereby counting the number of back EMF events.

6. The main / standby power switching management device with anti-backflow function according to claim 1, characterized in that, The backup battery discharge circuit (6) includes a controllable switch unit and an ideal diode unit. The controllable switch unit is connected in series in the airborne power bus and is controlled by the MCU minimum system and the CAN isolation circuit (5) to actively turn on or off the backup battery discharge circuit. The ideal diode unit is connected between the backup battery and the controllable switch unit and consists of an ORing controller and a MOS transistor. The ORing controller automatically controls the on / off state of the MOS transistor by detecting the pin voltage of the MOS transistor to achieve unidirectional current conduction from the backup battery to the airborne power bus and prevent reverse current from flowing into the battery.

7. The main / standby power switching management device with anti-backflow function according to claim 6, characterized in that, The MOSFETs in the controllable switching unit and the ideal diode unit are both selected to withstand a continuous conduction current of not less than 400A.

8. The main / standby power switching management device with anti-backflow function according to claim 6, characterized in that, The backup battery discharge circuit (6) further includes a status detection unit; the status detection unit generates a level signal indicating the on / off state of the discharge circuit according to the drive signal output by the ORing controller, and feeds it back to the MCU minimum system and CAN isolation circuit (5).

9. A control method based on the device according to any one of claims 1-8, characterized in that, include: System power-on procedure: Check the onboard power supply status; If the onboard power supply is not turned on, the system is powered on by triggering a mechanical switch and then powered by a backup battery. If the onboard power supply is already on, the system will automatically power on and be powered by the onboard power supply. Real-time monitoring and absorption steps: The bus voltage is continuously monitored by the back EMF absorption and detection circuit (2). When back EMF is detected, energy is automatically absorbed, and the MCU minimum system and CAN isolation circuit (5) count the events. At the same time, the backup battery voltage is monitored by the battery voltage acquisition circuit (4). Main and backup power switching and status monitoring steps: When the main power is normal, the MCU minimum system and CAN isolation circuit (5) control the backup battery discharge circuit (6) to turn off. When the main power failure causes the bus voltage to drop, the backup battery discharge circuit (6) automatically turns on to realize power supply switching and feeds back the discharge status signal to the MCU. System power-down steps: First, turn off the onboard power, and then, by pressing and holding the mechanical switch or receiving a remote power-down command, the MCU controls the system power output to cut off the power-down.

10. The control method according to claim 9, characterized in that, The real-time monitoring and absorption step and the main / backup power switching and status monitoring step also include a temperature protection process: the MCU minimum system and CAN isolation circuit (5) collect the temperature of the power MOS transistor in the backup battery discharge circuit (6) in real time through a temperature sensor; when the temperature exceeds the first preset safety threshold, the MCU minimum system and CAN isolation circuit (5) issues an overheat warning; when the temperature exceeds the higher second preset safety threshold, the MCU minimum system and CAN isolation circuit (5) directly control the controllable switching unit in the backup battery discharge circuit (6) to turn off, so as to implement overheat protection.

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