A power limit protection device and protection method for a tethered drone system

Abstract

The present invention provides a power limit protection device for a tethered unmanned aerial vehicle (UAV) system, comprising a DC power supply device, an airborne power conversion device, a motor, and a backup battery. The airborne power conversion device, the motor, and the backup battery are all arranged on the UAV. The airborne power conversion device is used to charge the backup battery and provide power for the motor for endurance. The motor is a high-voltage or low-voltage direct-driven brushless motor, and the brushless motor provides power for the tethered UAV. The DC power supply device is arranged on the ground and connected to the airborne power conversion device via a tethering cable. In the event of transient overpower of the tethered UAV system, the backup battery quickly switches its working mode to supplement power. The UAV system not only has an emergency landing capability, but also provides supplementary power when the instantaneous motor power exceeds the limit value, thereby greatly reducing the probability of the UAV crashing.

Description

Technical Field

[0001] The present invention belongs to the technical field of tethered unmanned aerial vehicles (UAVs), and in particular relates to a power limit protection device and a protection method for a tethered UAV system. Background Art

[0002] A tethered drone system uses a ground-based power supply and an onboard high-power power supply to convert high voltage to low voltage. To reduce line losses, the system typically converts the ground-based AC220V or AC380V input to a DC400-DC1000V or higher voltage. This voltage is then transmitted to the drone via a tethered cable, with a transmission distance of up to 100 to 300 meters.

[0003] Tethered drone systems are equipped with an onboard high-power power module, typically with a power range of 3kW to 20kW. The module's input voltage is the output voltage of the ground terminal, typically DC300-DC1000V. The onboard high-power power supply output voltage is 6s / 12s (25.2V, 50.4V). The high or low voltage output is directly supplied to the drone's motor. In this application, tethered drones remain in flight for more than 12 hours, placing extremely high demands on the reliability of the onboard power supply. Any abnormality in the onboard power supply could result in a crash. Therefore, the onboard system typically has a backup battery pack, typically with a voltage of 25.2V, 50.4V (6s / 12s series battery pack), or a 360V high-voltage battery.

[0004] During operation, a tethered drone system may experience a ground-based boost power failure, or a tethered cable breakage. In this situation, without a backup battery onboard for a short-term emergency landing, a crash could occur. While backup batteries are currently available for emergency landings, they cannot address the issue of transient overpower surges (when a tethered drone is subjected to sudden and intense wind disturbances at an altitude of several hundred meters, its power may exceed the ground power supply limit). To address both of these issues, the present application proposes a power limit protection device and method for a tethered drone system. Summary of the Invention

[0005] The purpose of the present invention is to provide a power limit protection device and protection method for a tethered drone system, which can realize seamless energy replenishment by a backup battery in the event of transient overpower of the tethered drone system, thereby reducing the probability of the drone crashing; at the same time, the tethered drone system can achieve a safe forced landing in the event of an abnormality in the ground power supply system and a damage to the tethering cable.

[0006] The present invention provides the following technical solutions:

[0007] A power limit protection device for a tethered unmanned aerial vehicle (UAV) system, comprising a DC power supply device, an onboard power conversion device, a motor, and a backup battery; the onboard power conversion device, the motor, and the backup battery are all arranged on the UAV; the onboard power conversion device is used for charging the backup battery and providing power for the motor's endurance; the motor is a high-voltage or low-voltage direct-driven brushless motor, and the brushless motor provides power for the tethered UAV; the DC power supply device is arranged on the ground and connected to the onboard power conversion device via a tethering cable; in the event of transient overpower of the tethered UAV system, the backup battery quickly switches its working mode to perform power replenishment.

[0008] Preferably, the tethered drone system also includes a power monitoring device, which includes a current sensor and a voltage sensor arranged on the motor power supply wire. The power monitoring device is used to calculate the current power value of the motor based on the signal data obtained by the current sensor and the voltage sensor.

[0009] Preferably, the power monitoring device also includes a data acquisition module, a switch and a data analysis module; the current sensor and the voltage sensor are respectively connected to the data acquisition module, the switch converts the current time domain signal data and the voltage time domain signal data received by the data acquisition module into current frequency domain signal data and voltage frequency domain signal data respectively through the FFT fast Fourier transform algorithm, and the data analysis module intercepts the spectrum peak of the current frequency domain signal data and the voltage frequency domain signal data output by the switch to calculate the current power limit.

[0010] Preferably, the transient overpower of the tethered drone system is when the current power limit is greater than the preset power limit of the tethered drone system.

[0011] Preferably, the DC power supply device includes at least 100 battery packs in series and 16 in parallel to provide 320V, 80HA power.

[0012] Preferably, the DC power supply equipment includes a status monitoring device, and the status monitoring device is used to monitor at least one of the operating voltage, operating current and operating temperature of the DC power supply equipment in real time.

[0013] A protection method for a power limit protection device of a tethered drone system, comprising the following steps:

[0014] S1. The motor of the tethered drone uses a high-voltage or low-voltage direct-driven brushless motor;

[0015] S2. The tethered UAV system operates in a mode where the power supplied by the onboard power conversion device is directly supplied to the motor, and the onboard power conversion device is connected to a backup battery;

[0016] S3. The output of the onboard power conversion device is used to charge the backup battery components and power the avionics of the tethered UAV system. The charging power is controllable.

[0017] S4. In the event of a transient overpower condition on the tethered drone motor, the backup battery quickly switches to a different operating mode to supply power to the tethered drone motor, ensuring stable operation of the tethered drone.

[0018] S5. When the DC power supply device of the tethered drone fails to output power due to an abnormality, the backup battery switches to supply power to the tethered drone motor and outputs an alarm signal at the same time, causing the tethered drone to enter an emergency landing state;

[0019] S6. When the mooring cable of the tethered drone is damaged, the backup battery switches to supply power to the motor of the tethered drone and outputs an alarm signal at the same time, and the tethered drone enters an emergency landing state.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a power limit protection device and protection method for a tethered drone system. The backup battery not only provides an emergency landing function, but also provides supplementary power when the instantaneous motor power exceeds the limit value, thereby greatly reducing the probability of the drone crashing; it maximizes the use of onboard equipment and improves the utilization rate of valuable onboard equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a schematic structural diagram of the present invention;

[0024] Figure 2 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION

[0025] like Figure 1 As shown, the power limit protection device of the tethered UAV system includes a DC power supply device, an airborne power supply conversion device, a motor and a backup battery; the airborne power supply conversion device, the motor and the backup battery are all arranged on the UAV, the airborne power supply conversion device is used to charge the backup battery and provide power for the motor's endurance, the motor is a high-voltage or low-voltage direct-driven brushless motor, and the brushless motor provides power for the tethered UAV; the DC power supply device is arranged on the ground and is connected to the airborne power supply conversion device through a tethering cable; in the case of transient overpower of the tethered UAV system, the backup battery quickly switches the working mode to supplement power.

[0026] In order to judge the transient overpower situation, a power monitoring device is provided on the tethered drone system. The power monitoring device includes a current sensor and a voltage sensor arranged on the motor power supply wire. The power monitoring device is used to calculate the current power value of the motor based on the signal data obtained by the current sensor and the voltage sensor; the power monitoring device also includes a data acquisition module, a switch and a data analysis module; the current sensor and the voltage sensor are respectively connected to the data acquisition module, and the switch converts the current time domain signal data and the voltage time domain signal data received by the data acquisition module into current frequency domain signal data and voltage frequency domain signal data respectively through the FFT fast Fourier transform algorithm. The data analysis module intercepts the spectrum peak of the current frequency domain signal data and the voltage frequency domain signal data output by the switch to calculate the current power limit; the transient overpower of the tethered drone system is when the current power limit is greater than the preset power limit of the tethered drone system.

[0027] The DC power supply equipment can use a battery pack consisting of at least 100 series and 16 parallel batteries to provide 320V, 80HA power supply; in order to determine the abnormality of the DC power supply equipment, the DC power supply equipment is provided with a status monitoring device, which is used to monitor at least one of the operating voltage, operating current and operating temperature of the DC power supply equipment in real time.

[0028] like Figure 2 As shown, the protection method of the power limit protection device of the tethered drone system includes the following steps:

[0029] S1. The motor of the tethered drone uses a high-voltage or low-voltage direct-driven brushless motor;

[0030] S2. The tethered UAV system operates in a mode where the power supplied by the onboard power conversion device is directly supplied to the motor, and the onboard power conversion device is connected to a backup battery;

[0031] S3. The output of the onboard power conversion device is used to charge the backup battery components and power the avionics of the tethered UAV system. The charging power is controllable.

[0032] S4. In the event of a transient overpower condition on the tethered drone motor, the backup battery quickly switches to a different operating mode to supply power to the tethered drone motor, ensuring stable operation of the tethered drone.

[0033] S5. When the DC power supply device of the tethered drone fails to output power due to an abnormality, the backup battery switches to supply power to the tethered drone motor and outputs an alarm signal at the same time, causing the tethered drone to enter an emergency landing state;

[0034] S6. When the mooring cable of the tethered drone is damaged, the backup battery switches to supply power to the motor of the tethered drone and outputs an alarm signal at the same time, and the tethered drone enters an emergency landing state.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A power limit protection device for a tethered drone system, characterized in that: The power limit protection device includes a DC power supply device, an airborne power conversion device, a motor and a backup battery; the airborne power conversion device, the motor and the backup battery are all arranged on the UAV, the airborne power conversion device is used to charge the backup battery and provide power for the motor, the motor is a high-voltage or low-voltage direct-driven brushless motor, and the brushless motor provides power for the tethered UAV; the DC power supply device is arranged on the ground and is connected to the airborne power conversion device through a tethering cable; in the event of transient overpower of the tethered UAV system, the backup battery quickly switches the working mode to supplement power; The tethered drone system further includes a power monitoring device, the power monitoring device including a current sensor and a voltage sensor provided on the motor power supply wire, the power monitoring device being configured to calculate a current power value of the motor based on signal data acquired by the current sensor and the voltage sensor; The power monitoring device further includes a data acquisition module, a switch, and a data analysis module; the current sensor and the voltage sensor are respectively connected to the data acquisition module; the switch converts the current time-domain signal data and the voltage time-domain signal data received by the data acquisition module into current frequency-domain signal data and voltage frequency-domain signal data respectively using an FFT (Fast Fourier Transform) algorithm; and the data analysis module extracts spectrum peaks from the current frequency-domain signal data and the voltage frequency-domain signal data output by the switch to calculate the current power limit; The DC power supply device includes a status monitoring device, which is used to monitor at least one of the operating voltage, operating current and operating temperature of the DC power supply device in real time.

2. The power limit protection device for a tethered drone system according to claim 1, characterized in that: The transient overpower of the tethered drone system is when the current power limit is greater than the preset power limit of the tethered drone system.

3. The power limit protection device for a tethered drone system according to claim 1, characterized in that: The DC power supply device includes at least 100 battery packs in series and 16 in parallel to provide 320V, 80HA power.

4. A protection method for a power limit protection device of a tethered drone system, characterized in that: The power limit protection device for a tethered drone system according to claim 1 comprises the following steps: S1. The motor of the tethered drone uses a high-voltage or low-voltage direct-driven brushless motor; S2. The tethered UAV system operates in a mode where the power supplied by the onboard power conversion device is directly supplied to the motor, and the onboard power conversion device is connected to a backup battery; S3. The output of the onboard power conversion device is used to charge the backup battery components and power the avionics of the tethered UAV system. The charging power is controllable. S4. In the event of a transient overpower condition on the tethered drone motor, the backup battery quickly switches to a different operating mode to supply power to the tethered drone motor, ensuring stable operation of the tethered drone. S5. When the DC power supply device of the tethered drone fails to output power due to an abnormality, the backup battery switches to supply power to the tethered drone motor and outputs an alarm signal at the same time, causing the tethered drone to enter an emergency landing state; S6. When the mooring cable of the tethered drone is damaged, the backup battery switches to supply power to the motor of the tethered drone and outputs an alarm signal at the same time, and the tethered drone enters an emergency landing state.

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