Unmanned aerial vehicle electrical system with multi-level power supply

Abstract

The invention relates to a multi-level power supply unmanned aerial vehicle electrical system, and solves the problem of unsuccessful risk of connecting a storage battery into a power grid after a single generator breaks down. Comprising a dual-redundancy direct-current power supply system, ground 28V and 12V power supplies, a 28V storage battery, a 12V tap power supply of the storage battery, a 12V generator, a ground control switch, a grid-connected control circuit and a power distribution manager, the grid-connected control circuit comprises a bus bar, a grid-connected power switch and a power diode; the bus bar comprises a task bus bar, an uninterrupted bus bar and an engine bus bar; the power distribution manager receives a main / standby generator power supply, ground 28V and 12V power supplies, a 28V storage battery and a 12V tap power supply of the storage battery to realize uninterrupted power supply of an uninterrupted bus bar load and an engine bus bar load respectively. A dual-redundancy power supply system and a mode that the storage battery is directly hung on a power grid are adopted, the voltage of an uninterrupted bus bar and the voltage of an engine bus bar are absolutely reliable, and the safety of the electrical system of the unmanned aerial vehicle is greatly improved.

Description

Technical Field

[0001] The present invention relates to an electrical system for an unmanned aerial vehicle (UAV), and in particular to a design of a multi-level power supply UAV electrical system. The present invention relates to the field of power supply for single-engine UAVs. The single-engine UAVs can be powered by piston engines or other types of engines, regardless of the type of engine. Background Art

[0002] The electrical system of a drone is composed of a power supply system and a distribution system. Currently, the power supply equipment for domestic 1.5T-level drones that use piston engines as power sources is basically a single-redundant generator plus an emergency battery.

[0003] Existing piston engines typically only have one 28V generator, making it difficult to guarantee the safety of drones in the event of a generator failure. Existing generator and emergency battery systems are typically designed using a power transfer method. This involves comparing voltages and finding a bus voltage below a certain threshold. This method then connects the battery to the grid through an analog circuit. This method introduces a risk of power transfer failure. Consequently, if the generator system experiences an anomaly, the emergency battery cannot function properly, posing a risk of a crash. Summary of the Invention

[0004] The purpose of this invention is to solve the disadvantage that a single-engine UAV can only carry one generator, and also to solve the problem of the risk of failure of battery integration into the power grid when the generator fails.

[0005] The present invention is achieved by the following technical solutions:

[0006] A multi-level power supply UAV electrical system includes a dual-redundant DC power supply system, ground 28V and 12V power supplies, a 28V battery and a battery 12V tap power supply, a 12V generator, a ground control switch, a grid-connected control circuit, and a power distribution manager;

[0007] The dual-redundant DC power supply system includes a dual-redundant permanent magnet synchronous generator, a rectifier, a main generator controller, and a backup generator controller. The generator contains two sets of generating windings, one for main generation and one for backup. The power system drives the AC generator to generate two three-phase AC power supplies. The rectifier contains two sets of full-bridge rectifier circuits, which respectively rectify the two three-phase AC power into two pulsating DC power supplies, which are respectively output to the main generation and backup generator controllers. After capacitor filtering, the DC-DC is converted into DC power, and then the output is controlled by the DC contactor.

[0008] The grid-connected control circuit includes a bus bar, a grid-connected power switch and a power diode. The bus bar includes a task bus bar, an uninterruptible bus bar and an engine bus bar. The grid-connected power switch includes a 12V battery tap power grid-connected power switch and a 28V battery grid-connected power switch. The grid-connected power switch is controlled by the ground-to-air switch. The power diode includes a power diode for unidirectionally connecting the power supply of the task bus bar to the uninterruptible bus bar; a power diode for unidirectionally connecting the power supply of the standby generator to the uninterruptible bus bar; and a power diode for unidirectionally connecting the 28V battery power supply to the uninterruptible bus bar.

[0009] The mission bus power source is the ground 28V power supply and the main generator, and the engine bus power source comes from the mission bus through a DC-DC module to convert the 12V power supply, the ground 12V power supply, the 12V generator DC power supply and the 28V battery 12V tap power supply;

[0010] The power distribution manager realizes uninterrupted power supply to the uninterrupted bus load and the engine bus load respectively by receiving the main / backup generator power supply, the ground 28V and 12V power supply, the 28V battery and the battery 12V tap power supply.

[0011] Furthermore, there are two 28V battery grid-connected power switches, which are redundant with each other, and each grid-connected power switch corresponds to a power diode.

[0012] Furthermore, there are three power diodes for unidirectionally connecting the power supply of the task bus bar to the uninterruptible bus bar, which are redundant to each other.

[0013] The power supply method of the grid-connected control circuit is as follows:

[0014] 1) Ground power supply

[0015] When the ground power supply is on, the ground 28V power supply is connected to the mission bus bar, and then connected to the uninterruptible bus bar in one direction through the power diode. The ground 12V power supply is connected to the engine bus bar.

[0016] 2) Aircraft normal power supply

[0017] When the main generator is supplying power normally, the main generator power supply is connected to the mission bus, and then to the uninterruptible bus in one direction through the power diode, and the 12V generator power supply is connected to the engine bus;

[0018] 3) Backup generator power supply

[0019] When the main generator fails to supply power normally, the backup generator power supply is unidirectionally connected to the uninterruptible bus through the power diode. At this time, the task bus has no power, and the 12V generator supplies power to the engine bus;

[0020] 4) Emergency power supply

[0021] When both the main and backup generators are unable to supply power normally, the power of the 28V battery is fed into the uninterruptible bus to ensure power supply to key equipment, and the 12V tap of the battery supplies power to the engine bus. At this time, the task bus has no power.

[0022] Furthermore, the battery is a lithium-ion battery that can be charged on board.

[0023] Furthermore, the 12V generator is a generator that comes with the engine.

[0024] Furthermore, the method for the ground-to-air switch to control the grid connection of the battery 28V and battery 12V tap power supplies is as follows: using a plug-in switch, connecting two of the pins of the plug-in switch to connect the battery 28V to the G pole of the two MOS tubes, the two MOS tubes are turned on, and the battery 28VDC and 12VDC are connected to the 28VDC bus and 12VDC bus respectively through the MOS tubes, thereby realizing the grid connection of the battery 28VDC and 12VDC; when two of the pins of the plug-in switch are connected, the other two pins will also be connected, and the 28V signal will flow to the AD acquisition module through the other two pins. This signal is used as the battery grid connection signal. After being collected by the equipment, it is transmitted to the UAV ground control station through the link for the operator's reference.

[0025] Furthermore, the battery 28VDC and 12VDC can be connected to the 28VDC bus bar and the 12VDC bus bar respectively by selecting a single or multiple MOS tubes of different specifications according to actual needs.

[0026] Furthermore, the plug-in switch is divided into a pin and a socket. The socket is installed near the maintenance cover of the drone. The pin hole is reserved when the drone body is designed. When operating the battery grid, there is no need to open the drone equipment cover and the maintenance cover. The battery grid can be connected by simply pulling out the pin. When the drone is parked on the ground, just insert the pin.

[0027] Beneficial effects of the invention:

[0028] The present invention adopts a dual-redundancy power supply system and a lithium-ion battery directly connected to the power grid. The uninterrupted bus and engine bus voltages are absolutely reliable, greatly improving the safety of the electrical system of this type of drone.

[0029] 1. When the main generator fails, the standby generator can supply power to the uninterrupted busbar;

[0030] 2. When the backup generator fails, the onboard batteries are already connected to the uninterruptible bus, so there is no need to switch power in the air, and the uninterruptible bus will not cause a power outage risk;

[0031] 3. When the 12V generator fails, the onboard battery has been connected to the engine bus, and there is no need for air power transfer, so there is no risk of power failure on the engine bus. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Design schematic diagram for the overall busbar of the UAV;

[0033] Figure 2 Schematic diagram of dual-redundant motor DC power supply system;

[0034] Figure 3-Figure 7 The schematic diagram of the grid-connected circuit and the power supply connection schematic diagram written for the drone in different power supply modes, among which, Figure 3 Grid-connected control circuit block diagram, Figure 4 Ground power supply configuration diagram, Figure 5 Main generator normal power supply configuration diagram, Figure 6 Standby generator power supply configuration diagram, Figure 7 Emergency power supply configuration diagram;

[0035] Figure 8 UAV battery grid-connected circuit. DETAILED DESCRIPTION

[0036] The present invention uses a dual-redundant permanent magnet synchronous power generation system, a lithium-ion battery that can be charged on board, and a 12V generator built into the engine to form the power supply system of this design. The power distribution manager sets the task bus, uninterruptible bus, and engine bus. The specific connection method is as follows Figure 1 shown. Figure 1 The UAV electrical system architecture features three busses: the mission bus, the uninterruptible bus, and the engine bus. The mission bus is powered primarily by the main generator and ground power. The uninterruptible bus is powered by the mission bus output to the uninterruptible bus via a diode; a backup generator; and a 28V lithium-ion battery pack. The engine bus is powered by the mission bus's 12V power converted via a DC-DC module; a 12V DC motor; and a 12V lithium-ion battery. This dual-redundant power system, comprising a 12V generator, lithium-ion battery, ground control switches, and a power distribution manager, forms a safe and reliable UAV electrical system.

[0037] 1. Power System Design

[0038] The DC power supply system consists of a dual-redundant permanent magnet synchronous generator, a rectifier, a main generator controller and a standby generator controller. The schematic diagram is as follows: Figure 2As shown, the generator contains two sets of generating windings, the main and standby. The power system drives the AC generator to generate two three-phase AC power supplies. The rectifier contains two sets of full-bridge rectifier circuits, which rectify the two three-phase AC into two pulsating DC, and output them to the main and standby generator controllers respectively. After capacitor filtering, the DC-DC is converted into 28.5V high-quality DC, and then output through the DC contactor.

[0039] 2. Design of power distribution manager for power level management

[0040] a) Uninterrupted power supply

[0041] The power distribution manager receives power from the main / backup generators, ground 28V and 12V power supplies, 28V batteries and battery 12V tap power to provide uninterruptible power to the bus (DC28V) loads and the engine bus (DC12V) loads.

[0042] The grid-connected control circuit can ensure uninterrupted busbar power supply in any power supply mode, such as Figure 3 As shown: This circuit mainly consists of busbars, grid-connected power switches and power diodes. Among them:

[0043] 1) The bus includes the mission bus, uninterrupted bus and engine bus;

[0044] 2) The grid-connected power switches include: 12V battery tap power grid-connected switch K1, 28V battery grid-connected switches K2 and K3 (K2 and K3 are redundant with each other). The grid-connected power switches are controlled on and off by the ground-to-air switch;

[0045] 3) Power diodes include D1, D2, D3, D4, D5, and D6. D1, D2, and D3 are redundant and are used to connect the mission bus's power supply to the uninterruptible bus in one direction. D4 is used to connect the backup generator's power supply to the uninterruptible bus in one direction. D5 and D6 are used for the 28V battery grid-connected line to prevent reverse current flow and protect the lithium battery.

[0046] Before the aircraft takes off, the ground-to-air switch (28V / on, 28V effective) controls the grid-connected power switches K1, K2 and K3 to be turned on, and the 28V battery and the battery 12V tap power supply are connected to the uninterruptible bus and the engine bus respectively.

[0047] The grid-connected control circuit ensures uninterrupted busbar power supply in any power supply mode, as follows:

[0048] 1) Ground power supply

[0049] When the ground is powered, the ground 28V power supply is connected to the mission bus bar, and then connected to the uninterruptible bus bar through the power diodes D1, D2, and D3. The ground 12V power supply is connected to the engine bus bar. Figure 4 shown.

[0050] 2) Aircraft normal power supply

[0051] When the main generator is supplying power normally, the 29.5V power supply of the main generator is connected to the task bus bar, and then connected to the uninterruptible bus bar in one direction through the power diodes D1, D2, and D3. The 12V generator power supply is connected to the engine bus bar, such as Figure 5 shown.

[0052] 3) 1kW backup generator power supply

[0053] When the 4kW main generator fails to supply power, the 1kW standby generator's 28.5V power supply is connected to the uninterruptible busbar through the power diode D4. At this time, the mission busbar has no power. The 12V generator supplies power to the engine busbar. Figure 6 shown.

[0054] 4) Emergency power supply

[0055] When the main and standby generators cannot supply power normally, the power of the 28V battery is fed into the uninterruptible bus to ensure the power supply of key equipment, and the 12V tap of the battery supplies power to the engine bus. At this time, the task bus has no power. Figure 7 shown.

[0056] The present invention has the following characteristics:

[0057] 1. Dual-redundant DC power supply system design

[0058] The aircraft engine drives a dual-redundant permanent magnet synchronous generator to generate AC power, which is then rectified into pulsating DC power by the generator rectifier. The pulsating DC power is converted and filtered by the generator controller, and the voltage is stabilized to 28.5V DC power. Finally, the output is controlled by the DC contactor to provide 4kW main power and 1kW backup power for the aircraft.

[0059] 2. Design of grid-connected lithium-ion battery controlled by ground-to-air switch

[0060] The principle of the battery grid-connected circuit in the present invention is as follows Figure 8As shown, by connecting pins 3 and 4 via a plug-in switch, the battery's 28V voltage is connected to the G terminals of two MOS transistors. The two MOS transistors are then conductive, and the battery's 28VDC and 12VDC are connected to the 28VDC and 12VDC buses, respectively, through the MOS transistors, thus achieving grid-connected operation. When pins 3 and 4 are connected, pins 1 and 2 are also connected, and the 28V signal flows through pins 1 and 2 to the AD acquisition module. This signal serves as the battery grid-connected signal. After being collected by the device, it is transmitted via a link to the UAV ground control station for operator reference. The MOS transistors in the figure are schematic; single or multiple MOS transistors of varying specifications can be selected based on actual needs.

[0061] The plug-in switch is divided into a pin and a socket. The socket is installed near the maintenance cover of the drone. The pin hole is reserved when the drone body is designed. When operating the battery grid, there is no need to open the drone equipment cover and maintenance cover. You only need to pull out the pin to achieve battery grid connection. When the drone is parked on the ground, just insert the pin.

[0062] 3. The power distribution manager designs the power supply for each bus.

[0063] The professional terms and glossaries involved in the present invention are as follows:

[0064] Power distribution manager: Integrates multiple power inputs of the drone and distributes them to the devices that need power in an orderly manner;

[0065] Dual-redundant DC power supply system: consists of two DC generators, rectifiers, and two generator controllers;

[0066] Emergency power supply: lithium-ion battery pack provides emergency power for the drone;

[0067] Ground-to-air switch: An electrical switch powered by a lithium-ion battery pack. When unplugged, the lithium-ion battery pack is automatically connected to the drone power grid, and when plugged in, the lithium-ion battery pack is disconnected from the grid.

[0068] Busbar: A multi-layered electrical connection component for power modules that can connect the power distribution points of multiple circuits and is widely used in aviation power systems.

Claims

1. A multi-level power supply UAV electrical system, characterized by: Includes dual-redundant DC power supply system, ground 28V and 12V power supplies, 28V battery and battery 12V tap power supply, 12V generator, ground control switch, grid control circuit and distribution manager; The dual-redundant DC power supply system includes a dual-redundant permanent magnet synchronous generator, a rectifier, a main generator controller, and a backup generator controller. The generator contains two sets of generating windings, one for main generation and one for backup. The power system drives the AC generator to generate two three-phase AC power supplies. The rectifier contains two sets of full-bridge rectifier circuits, which respectively rectify the two three-phase AC power into two pulsating DC power supplies, which are respectively output to the main generation and backup generator controllers. After capacitor filtering, the DC-DC is converted into DC power, and then the output is controlled by the DC contactor. The grid-connected control circuit includes a bus bar, a grid-connected power switch and a power diode. The bus bar includes a task bus bar, an uninterruptible bus bar and an engine bus bar. The grid-connected power switch includes a 12V battery tap power grid-connected power switch and a 28V battery grid-connected power switch. The grid-connected power switch is controlled by the ground-to-air switch. The power diode includes a power diode for unidirectionally connecting the power supply of the task bus bar to the uninterruptible bus bar; a power diode for unidirectionally connecting the power supply of the standby generator to the uninterruptible bus bar; and a power diode for unidirectionally connecting the 28V battery power supply to the uninterruptible bus bar. The mission bus power source is the ground 28V power supply and the main generator, and the engine bus power source comes from the mission bus through a DC-DC module to convert the 12V power supply, the ground 12V power supply, the 12V generator DC power supply and the 28V battery 12V tap power supply; The power distribution manager realizes uninterrupted power supply to the uninterrupted bus load and the engine bus load respectively by receiving the main / backup generator power supply, the ground 28V and 12V power supply, the 28V battery and the battery 12V tap power supply.

2. The multi-level power supply UAV electrical system according to claim 1, characterized in that: There are two 28V battery grid-connected power switches, which are redundant with each other, and each grid-connected power switch corresponds to a power diode.

3. The multi-level power supply UAV electrical system according to claim 1, characterized in that: There are three power diodes used to connect the power of the mission bus bar to the uninterruptible bus bar in one direction, which are redundant to each other.

4. The multi-level power supply UAV electrical system according to claim 1, characterized in that: The power supply method of the grid-connected control circuit is as follows: 1) Ground power supply When the ground power supply is on, the ground 28V power supply is connected to the mission bus bar, and then connected to the uninterruptible bus bar in one direction through the power diode. The ground 12V power supply is connected to the engine bus bar. 2) Aircraft normal power supply When the main generator is supplying power normally, the main generator power supply is connected to the mission bus, and then to the uninterruptible bus in one direction through the power diode, and the 12V generator power supply is connected to the engine bus; 3) Backup generator power supply When the main generator fails to supply power normally, the backup generator power supply is unidirectionally connected to the uninterruptible bus through the power diode. At this time, the task bus has no power, and the 12V generator supplies power to the engine bus; 4) Emergency power supply When both the main and backup generators are unable to supply power normally, the power of the 28V battery is fed into the uninterruptible bus to ensure power supply to key equipment, and the 12V tap of the battery supplies power to the engine bus. At this time, the task bus has no power.

5. The multi-level power supply UAV electrical system according to claim 1, characterized in that: The battery is a lithium-ion battery that can be charged on board.

6. The multi-level power supply UAV electrical system according to claim 1, characterized in that: The 12V generator is a generator that comes with the engine.

7. The multi-level power supply UAV electrical system according to claim 1, characterized in that: The method of controlling the grid connection of the battery 28V and battery 12V tap power supplies by the ground-to-air switch is as follows: using a plug-in switch, connecting two of the pins of the plug-in switch to connect the battery 28V to the G pole of the two MOS tubes. The two MOS tubes are turned on, and the battery 28VDC and 12VDC are connected to the 28VDC bus and 12VDC bus respectively through the MOS tubes, thereby realizing the grid connection of the battery 28VDC and 12VDC; when two of the pins of the plug-in switch are connected, the other two pins are also connected, and the 28V signal flows to the AD acquisition module through the other two pins. This signal serves as the battery grid connection signal. After being collected by the equipment, it is transmitted to the UAV ground control station through the link for the operator's reference.

8. The multi-level power supply UAV electrical system according to claim 7, characterized in that: The battery 28VDC and 12VDC can be connected to the 28VDC bus bar and the 12VDC bus bar respectively by selecting a single or multiple MOS tubes of different specifications according to actual needs.

9. The multi-level power supply UAV electrical system according to claim 1, characterized in that: The plug-in switch is divided into a pin and a socket. The socket is installed near the maintenance cover of the drone. The pin hole is reserved when the drone body is designed. When operating the battery grid, there is no need to open the drone equipment cover and maintenance cover. You only need to pull out the pin to achieve battery grid connection. When the drone is parked on the ground, just insert the pin.

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