A dual-battery online balancing charging system for drones

Abstract

The present invention discloses an online balanced charging system for dual batteries of unmanned aerial vehicles, comprising a cabin, a charging control board, a docking assembly, and a battery control board; the charging control board comprises an MCU module, a first communication module, a second communication module, a first output control circuit, and a second output control circuit; the MCU module sends a charging control signal to the first output control circuit and the second output control circuit, and based on a preset charging current, adaptively charges the first battery and the second battery simultaneously, so that the first battery and the second battery adaptively distribute the charging current with the power balance as the constraint condition until both reach the slow charging voltage at the same time. During the charging process, the present invention automatically distributes the current by the hardware circuit, and the current automatically flows to the low-power battery pack, without the need for real-time monitoring and intervention by software, thereby effectively solving the problems of online charging and balanced charging of the batteries and realizing automated charging and balanced charging of the batteries on both sides.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) power management, and in particular to an online balancing charging system for dual batteries of UAVs. Background Art

[0002] With technological advancements and growing market demand, drone technology has achieved significant growth in the past few years. Drone applications have continuously expanded, moving from their initial military applications to include civilian applications such as logistics and transportation, agricultural monitoring, environmental protection, security inspections, film and television production, and disaster relief. To meet the stringent requirements of these diverse applications for endurance, payload capacity, and system reliability, many drone manufacturers are adopting dual-battery power systems.

[0003] The introduction of a dual-battery system brings significant advantages to drones. First, it significantly improves drones' endurance, allowing them to stay airborne longer and complete more complex missions. Second, it increases a drone's payload capacity, enabling it to carry more equipment or cargo to meet the needs of diverse application scenarios. Furthermore, a dual-battery system provides increased system redundancy, improving the reliability and safety of drones. If one battery fails, the other can continue to provide power, ensuring the drone's normal operation.

[0004] However, dual-battery systems also present technical challenges in charging and management. Traditional drone battery charging systems typically utilize a separate charging box. This method requires the batteries to be removed from the drone and inserted into the charging box for charging. The charging box balances the two batteries, ensuring that the voltage and capacity of the two batteries are consistent, thereby ensuring battery availability and safety. However, this charging method requires manual intervention, is cumbersome, and can cause wear and tear on the battery connectors with frequent use. Furthermore, the battery removal process can increase drone downtime, affecting its efficiency.

[0005] Another common charging method is online charging, which allows for charging without removing the battery. While this method simplifies the process, since the batteries are typically charged independently, it can easily lead to voltage mismatches between the two batteries. This voltage mismatch can prevent the drone from taking off even when the total battery charge is sufficient, as the battery management system detects the significant voltage difference and prevents the drone from starting. This voltage mismatch not only affects the drone's normal operation but can also negatively impact the battery's lifespan and performance.

[0006] Patent publication number CN117977737A discloses an on-board dual-battery automatic charging control system and method. This system uses a charging port to simultaneously charge both batteries, monitoring the battery levels in real time to prioritize charging the battery with the lowest charge. However, this invention requires a current-limiting resistor and real-time battery level monitoring during charging, placing high demands on both software and hardware.

[0007] The invention with publication number CN113508509A discloses a charging control method, circuit, device, and storage medium. The charging control circuit includes a main control circuit, a charging interface circuit, and at least two charging circuits. The charging interface circuit can connect to different types of chargers. The charging circuit is used to connect between the charging interface circuit and the battery, and different charging circuits are used to adapt to different types of chargers. When a charger is connected to the charging interface circuit, the main control circuit is used to identify the type of charger and select a charging circuit that is compatible with the charger type to charge the battery. This invention also monitors the remaining charge of multiple batteries and continuously adjusts the charging current of each charging circuit to achieve simultaneous charging of multiple batteries, which requires high software and hardware requirements.

[0008] Furthermore, online charging of these batteries also has certain shortcomings in terms of charging efficiency and safety. Due to the lack of an effective voltage balancing mechanism, the battery may overcharge or undercharge during the charging process, affecting its lifespan and performance. Overcharging can cause the battery to overheat, increasing safety risks, while undercharging can lead to insufficient battery capacity, affecting the drone's flight endurance.

[0009] Therefore, how to achieve online balanced charging of drone batteries without increasing operational complexity has become an urgent problem to be solved in the current industry. Summary of the Invention

[0010] The purpose of the present invention is to disclose an online balanced charging system for dual batteries of unmanned aerial vehicles. During the charging process, the hardware circuit automatically distributes the current, and the current automatically flows to the low-battery battery pack without the need for real-time monitoring and intervention by software, thereby effectively solving the problems of online charging and balanced charging of the batteries and realizing automated charging and balanced charging of batteries on both sides.

[0011] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0012] A dual-battery online balancing charging system for a drone, comprising a cabin, a charging control board, a docking assembly, and a battery control board;

[0013] The docking assembly includes a cabin-side docking piece, a drone-side docking piece, and a position detection circuit; when the cabin-side docking piece and the drone-side docking piece are fully in contact, the position detection circuit sends a drone position signal to the charging control board;

[0014] The charging control board, the cabin-side docking piece, and the docking signal generating circuit are installed in the cabin; the battery control board and the drone-side docking piece are installed on the drone, and the battery control board includes a first battery control unit and a second battery control unit;

[0015] The charging control board includes an MCU module, a first communication module, a second communication module, a first output control circuit, and a second output control circuit; the first output control circuit and the first communication module are connected to the first battery of the drone through the first battery control board, and the second output control circuit and the second communication module are connected to the second battery of the drone through the second battery control board;

[0016] The MCU module responds to the drone in-position signal and synchronously sends an inquiry signal to the first communication module and the second communication module to complete the communication interaction with the first battery control board and the second battery control board. After receiving the battery pack power parameters returned by the first battery control board and the second battery control board, the MCU module sends a charging control signal to the first output control circuit and the second output control circuit to adaptively charge the first battery and the second battery based on the preset charging current, so that the first battery and the second battery are adaptively allocated the charging current with power balance as the constraint condition until both reach the slow charging voltage at the same time;

[0017] The first output control circuit and the second output control circuit have the same structure, and both include a first switch circuit, a switch enabling circuit, a first enabling circuit, a second switch circuit, a second enabling circuit, and a power determination circuit; the second switch circuit is connected between the charging input terminal and the charging output terminal;

[0018] The first switch circuit is connected to the MCU module, receives the charging control signal sent by the MCU module, outputs a first level signal to the switch enable circuit, and the switch enable circuit outputs a second level signal to the first enable circuit to turn on the second enable circuit and the power judgment circuit; the second enable circuit and the power judgment circuit simultaneously compare the charging input voltage and the charging output voltage. When the charging output voltage is lower than the charging input voltage, the second enable circuit continues to charge the second switch circuit to turn on the second switch circuit until the charging output voltage is higher than the charging input voltage, and the power judgment circuit turns off the second switch circuit.

[0019] Furthermore, the first switch circuit includes a first transistor, a second transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor;

[0020] The base of the first transistor is connected to the MCU module through the first resistor on the one hand, and is grounded through the fourth resistor on the other hand. The collector of the first transistor is connected to the charging input terminal through the second resistor and the third resistor in sequence, and the emitter of the first transistor is grounded through the fifth resistor; the base of the second transistor is connected to the connection point of the second resistor and the third resistor, and the emitter of the second transistor is connected to the charging input terminal through the sixth resistor; the collector of the second transistor is grounded through the seventh resistor and the eighth resistor in sequence on the one hand, and is connected to the switch enable circuit on the other hand. Furthermore, the first enable circuit uses a first NMOS transistor, the source and drain of the first NMOS transistor are respectively connected in parallel to the input and output of the second enable circuit and the power judgment circuit, the gate of the first NMOS transistor is connected to the output of the switch enable circuit, and the drain of the first NMOS transistor is connected to the second switch circuit;

[0021] When the switch enable circuit outputs a second level signal to the gate of the first NMOS transistor, the first NMOS transistor is turned off to turn on the second enable circuit and the power judgment circuit; otherwise, the first NMOS transistor remains in the on state, short-circuiting the second enable circuit and the power judgment circuit while outputting a drain voltage to turn off the second switch circuit.

[0022] Furthermore, the switch enabling circuit includes a ninth resistor, a tenth resistor, and a third transistor; the base of the third transistor is connected to the output of the first switch circuit via the ninth resistor, the collector is connected to the charging input via the tenth resistor, and the emitter is grounded. Furthermore, the second enabling circuit utilizes a charge pump and a first amplifier, and the battery level determination circuit utilizes a second amplifier; the positive electrode of the first amplifier is connected to the charging input, and the negative electrode is connected to the charging output via a first fine-tuning circuit. When the charging input voltage is greater than the charging output voltage, the charge pump continuously charges the second switch circuit to turn on the second switch circuit until the charging output voltage is higher than the charging input voltage.

[0023] The power determination circuit uses a second amplifier and a second NMOS tube; the drain of the second NMOS tube is connected to the second switch circuit, and the gate is connected to the output end of the second amplifier; the positive electrode of the second amplifier is connected to the charging output end, and the negative electrode is connected to the charging input end through a second fine-tuning circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS tube is turned on and outputs a drain voltage to turn off the second switch circuit.

[0024] Furthermore, the second switch circuit adopts a third NMOS transistor and a fourth NMOS transistor;

[0025] The drain of the third NMOS transistor is connected to the charging output terminal, and the drain of the fourth NMOS transistor is connected to the charging input terminal; the source and gate of the third NMOS transistor and the fourth NMOS transistor are connected to each other, and the gates of both are connected to the output terminals of the first enabling circuit, the second enabling circuit, and the power determination circuit.

[0026] Furthermore, the in-position detection circuit includes a ground terminal, a communication power supply circuit and a charging enabling circuit;

[0027] The output end of the communication power supply circuit is connected to the communication module on the drone side, and the output end of the charging enabling circuit is connected to the charging input end;

[0028] The grounding terminal is located on the cabin side docking piece. When the cabin side docking piece is connected to the drone side docking piece, the grounding terminal is grounded and outputs a low-level signal to the MCU module, so that the MCU module starts the communication power supply circuit and provides the first communication module and the second communication module with a working voltage. The first communication module and the second communication module send the battery pack power parameter to the MCU module, and the MCU module starts the charging enable circuit to provide a charging input voltage to the charging input end.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] First, the drone dual-battery online balancing charging system of the present invention optimizes the battery power supply system and ensures dual-battery voltage balance by prioritizing charging of low-battery batteries, thereby avoiding takeoff problems caused by voltage mismatch.

[0031] Second, the drone dual-battery online balanced charging system of the present invention effectively solves the problems of online battery charging and balanced charging, realizes automated charging and balanced charging of batteries on both sides, supports higher load capacity, and meets diverse application needs.

[0032] Third, the drone dual-battery online balanced charging system of the present invention avoids overcharging or undercharging of the batteries during the charging process, improves the battery life and performance, extends the flight time of the drone, improves the endurance, significantly improves the efficiency and safety of the drone, and opens up new possibilities for the development and application of drone technology.

[0033] Fourth, the drone dual-battery online balanced charging system of the present invention does not need to rely on software communication, and can achieve adaptive current distribution through hardware circuits, with good stability and low computing energy consumption. By reasonably setting the constant current charging current, it ensures that the high current generated instantly during charging due to unstable connection will not cause damage to the battery, reducing the charging risk, and is particularly suitable for charging drones in areas with multiple vibrations.

[0034] Fifth, in the drone dual-battery online balanced charging system of the present invention, the switches and enable signals of the entire circuit rely on dividing or comparing the charging input voltage. Therefore, there is no need to additionally configure a control power supply for the charging system. While improving system safety, it can also be adapted to most charging piles on the market, and is particularly suitable for rapid power distribution to drones when operating in the field. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the docking method between the cabin of the UAV dual-battery online balanced charging system of the present invention and the UAV;

[0036] Figure 2 This is a structural diagram of the charging control board;

[0037] Figure 3 This is a schematic diagram of the module framework of the output control circuit;

[0038] Figure 4 is a schematic diagram of a circuit for implementing a first switch circuit;

[0039] Figure 5 A schematic diagram of an implementation circuit of a switch enabling circuit, a first enabling circuit, a second switch circuit, a second enabling circuit, and a power determination circuit;

[0040] Figure 6 Schematic diagram of the in-place detection circuit, where (a) is the connector signal schematic, (b) is the A-way in-place detection protection circuit, and (c) is the B-way in-place detection protection circuit. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0042] See also Figure 1 The present invention discloses an online balanced charging system for dual batteries of an unmanned aerial vehicle, which includes a cabin, a charging control board, a docking assembly and a battery control board.

[0043] The docking assembly includes a cabin side docking piece, a drone side docking piece and a position detection circuit; when the cabin side docking piece and the drone side docking piece are fully in contact, the position detection circuit sends a drone position signal to the charging control board.

[0044] The charging control board, the cabin side docking piece and the docking signal generating circuit are installed in the cabin; the battery control board and the drone side docking piece are installed on the drone, and the battery control board includes a first battery control unit and a second battery control unit.

[0045] See also Figure 2The charging control board includes an MCU module, a first communication module, a second communication module, a first output control circuit and a second output control circuit; the first output control circuit and the first communication module are connected to the first battery of the drone through the first battery control board, and the second output control circuit and the second communication module are connected to the second battery of the drone through the second battery control board.

[0046] The MCU module responds to the drone's position signal and synchronously sends an inquiry signal to the first communication module and the second communication module to complete the communication interaction with the first battery control board and the second battery control board. After receiving the battery pack power parameters returned by the first battery control board and the second battery control board, the MCU module sends a charging control signal to the first output control circuit and the second output control circuit. Based on the preset charging current, the first battery and the second battery are adaptively charged at the same time, so that the first battery and the second battery adaptively distribute the charging current with power balance as the constraint condition until both reach the slow charging voltage at the same time.

[0047] See also Figure 3 The first output control circuit and the second output control circuit have the same structure, both including a first switching circuit, a switch enabling circuit, a first enabling circuit, a second switching circuit, a second enabling circuit and a power judgment circuit; the second switching circuit is connected between the charging input end and the charging output end.

[0048] The first switch circuit is connected to the MCU module, receives the charging control signal sent by the MCU module, and outputs a first level signal to the switch enable circuit. The switch enable circuit outputs a second level signal to the first enable circuit to turn on the second enable circuit and the battery level judgment circuit. The second enable circuit and the battery level judgment circuit simultaneously compare the charging input voltage and the charging output voltage. When the charging output voltage is lower than the charging input voltage, the second enable circuit continues to charge the second switch circuit to turn on the second switch circuit until the charging output voltage is higher than the charging input voltage, at which point the battery level judgment circuit turns off the second switch circuit.

[0049] Unlike the existing technology that uses software to detect the battery pack power in real time and adjusts the charging voltage of the two battery packs according to the detection results to balance the power of the two battery packs, the present invention only needs to collect the battery pack power parameters through the communication module before charging starts, and set the charging current according to the collected battery pack power parameters. Then the first output control circuit and the second output control circuit will automatically distribute the charging current, first charging the low-power battery, and continuously narrowing the power difference between the two batteries. After the power difference reaches a certain level, the charging current is adaptively distributed, and the two batteries are charged at different speeds at the same time, continuing to narrow the power difference between the two batteries until the power of the two batteries is balanced and reaches the slow charging voltage at the same time.

[0050] See also Figure 4The first switch circuit includes a first transistor T1, a second transistor T2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The base of the first transistor T1 is connected to the MCU module through the first resistor R1 on the one hand, and is grounded through the fourth resistor R4 on the other hand. The collector of the first transistor T1 is connected to the charging input terminal VCC_IN through the second resistor R2 and the third resistor R3 in sequence, and the emitter of the first transistor T1 is connected to the ground GND through the fifth resistor R5. The base of the second transistor T2 is connected to the connection point of the second resistor R2 and the third resistor R3, and the emitter of the second transistor T2 is connected to the charging input terminal VCC_IN through the sixth resistor R6. The collector of the second transistor T2 is connected to the ground GND through the seventh resistor R7 and the eighth resistor R8 in sequence, and is connected to the switch enable circuit on the other hand.

[0051] See also Figure 5 The switch enabling circuit includes a ninth resistor R9, a tenth resistor R10, and a third transistor T3; the base of the third transistor T3 is connected to the output terminal V1 of the first switch circuit through the ninth resistor R9, the collector is connected to the charging input terminal VCC_IN through the tenth resistor R10, and the emitter is grounded.

[0052] The first enabling circuit uses a first NMOS transistor M1. The source and drain of the first NMOS transistor M1 are connected in parallel to the input and output of the second enabling circuit and the power determination circuit, respectively. The gate of the first NMOS transistor M1 is connected to the output of the switch enabling circuit, and the drain of the first NMOS transistor M1 is connected to the second switch circuit. When the switch enabling circuit outputs a second level signal to the gate of the first NMOS transistor M1, the first NMOS transistor M1 is turned off to turn on the second enabling circuit and the power determination circuit. Otherwise, the first NMOS transistor M1 remains in the on state, short-circuiting the second enabling circuit and the power determination circuit while outputting a drain voltage to turn off the second switch circuit.

[0053] Assume that the voltages of the first and second batteries to be charged are 20V and 40V, respectively, and the maximum charging input voltage is 60V. When the MCU module does not send a charging control signal, the first and second transistors in the first switch circuit are both disconnected. The voltage signal received by the switch enable circuit is 0, and the gate voltage of the first NMOS transistor is low. The first NMOS transistor is turned on, shorting the second enable circuit and the battery level determination circuit. Simultaneously, the drain voltage is high, turning off the second switch circuit and disconnecting the charging input and output terminals. Both the first and second batteries are in an uncharged state. When the MCU module sends a charging control signal (approximately 3.3V) to the first switch circuits of the first and second output control circuits, the first and second transistors are turned on sequentially, dividing the charging input voltage and sending it to the switch enable circuit for boosting. The gate voltage of the first NMOS transistor is high, disconnecting the first NMOS transistor, and the second enable circuit and the battery level determination circuit begin operating. The second enable circuit and the battery level determination circuit adaptively control the on / off state of the second switch circuit based on the remaining battery levels of the first and second batteries.

[0054] Exemplarily, the second enabling circuit uses a charge pump and a first amplifier IOP1. The positive electrode of the first amplifier IOP1 is connected to the charging input terminal VCC_IN, and the negative electrode is connected to the charging output terminal VOUT through a first fine-tuning circuit. When the charging input voltage is greater than the charging output voltage, the charge pump continuously charges the second switching circuit to turn on the second switching circuit until the charging output voltage is higher than the charging input voltage. The power determination circuit uses a second amplifier IOP2 and a second NMOS transistor M2. The drain of the second NMOS transistor M2 is connected to the second switching circuit, and the gate is connected to the output terminal of the second amplifier IOP2. The positive electrode of the second amplifier IOP2 is connected to the charging output terminal VOUT, and the negative electrode is connected to the charging input terminal VCC_IN through a second fine-tuning circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS transistor M2 is turned on and outputs a drain voltage to turn off the second switching circuit.

[0055] The second switch circuit uses a third NMOS transistor M3 and a fourth NMOS transistor M4; the drain of the third NMOS transistor M3 is connected to the charging output terminal, and the drain of the fourth NMOS transistor M4 is connected to the charging input terminal; the source and gate of the third NMOS transistor M3 and the fourth NMOS transistor M4 are connected to each other, and the gates of both are connected to the output terminals of the first enabling circuit, the second enabling circuit, and the power determination circuit.

[0056] Figure 5 The third amplifier IOP3 is used to detect the negative input potential on the MOSFET source (SOURCE) pin and quickly pull the gate (GATE) voltage down to the source level, thereby turning off the MOSFET and achieving electrical isolation between the load and the negative input.

[0057] When the first NMOS transistor M1 is turned off, the first amplifier IOP1 and the second amplifier IOP2 simultaneously determine the voltage difference between the charging input terminal VCC_IN and the charging output terminal VOUT. Preferably, to increase the sensitivity of the two amplifiers, a millivolt-level voltage trimming circuit is added to the negative input terminal of the first amplifier IOP1 and the positive input terminal of the second amplifier IOP2, respectively, to cause the charging circuit and the charge determination circuit to generate different output voltage signals when the battery is about to be fully charged. The specific values of the voltage trimming circuits and the buck-boost mode can be customized according to actual charging needs. When the voltage at the charging input terminal is greater than the voltage at the charging output terminal, the second NMOS transistor M2 is turned off, the first amplifier IOP1 outputs a positive voltage, and the second switch circuit is turned on, connecting the charging input terminal VCC_IN and the charging output terminal VOUT to charge the battery. During this process, the charge pump converts the low voltage into a high voltage by alternating charging and discharging of the capacitor and the switch. In this example, by boosting the input voltage, the output terminal is connected to the gate of the NMOS, so that the gate voltage of the NMOS is greater than the source voltage, keeping the NMOS in the open state.

[0058] To achieve adaptive charging current distribution, the MCU module first calculates the maximum charging current (e.g., 10A) during the constant current phase based on the fed-back battery parameters. The charging input voltage is then continuously increased from 0V. When the charging input voltage exceeds 20V, the second switch circuit of the first output control circuit is turned on. At this point, because the charging input voltage is still lower than the voltage of the second battery, the second switch circuit of the second output control circuit has not yet turned on. Therefore, only the first battery begins charging at a charging rate of 10A. To maintain the constant current, the charging input voltage continues to rise until it exceeds 40V, at which point the second switch circuit of the second output control circuit turns on. The first and second batteries begin charging simultaneously, and the charging current is automatically distributed based on the voltage difference. In the present invention, during the constant current phase, the total current in the two charging circuits remains constant. Even if one battery's charging circuit is disconnected due to environmental factors or a problem with the drone itself, the other battery will not be damaged by the instantaneous high current. This makes the balanced charging system of the present invention particularly suitable for charging drones in harsh environments or with poor charging pile connectivity, such as outdoor environments with high vibration levels. In addition, the charging process of the present invention does not need to rely on software communication, and can achieve adaptive current distribution by relying on hardware circuits, which has good stability and low computing energy consumption.

[0059] The maximum charging current during constant current can be determined according to the actual application scenario. For example, the smaller rated charging current of the two battery packs is selected as the maximum charging current to ensure that the high current generated instantly during charging due to unstable connection will not damage the battery. In actual applications, the drone can be charged with power off or charged in standby mode. When charging in standby mode, a charging judgment program can be set in the drone. If one or both connection terminals are disconnected due to external vibration, the charging pile can be reconnected after the environment stabilizes and balanced charging can be performed again, thereby reducing the workload of the staff. At the same time, the built-in program has high stability and is less dependent on the communication quality between the drone and the cabin. Even if the RS485 communication modules of the two are disconnected, the charging process can be automatically restored while ensuring charging safety.

[0060] As a preferred example, Figure 6 is a schematic diagram of the in-position detection circuit, as shown in Figure 6 As shown in the figure, (a) shows the connector signal schematic, (b) shows the A-way presence detection protection circuit, and (c) shows the B-way presence detection protection circuit. Diodes D15 and D24 are ESD protection diodes, while diodes D14 and D23 provide voltage protection to prevent damage to the MCU GPIO caused by high voltages from external interfaces. Their anodes are connected to the voltage source VDD_3V3 through resistors R34 and R29, respectively, to obtain a 3.3V operating voltage. The A_GND_CTRL and B_GND_CTRL signals, after being protected by the diodes, are directly connected to the MCU. When the devices are plugged in, the A_GND_CTRL# and B_GND_CTRL# signals on the docking interface are pulled low, and the A_GND_CTRL and B_GND_CTRL signals are also pulled low due to the unidirectional conductivity of the diodes. In practice, after the external interface is plugged in, the cathodes of diodes D14 and D23 are grounded. The presence of the target battery is detected by the potential change of the MCU GPIO. Once the MCU detects the target battery, it opens the communication power supply circuit to power the battery-side communication board. After the battery-side communication board is powered on, it exchanges data with the charging control board via RS485 signals, finally opening the battery charging circuit.

[0061] The presence detection circuit first confirms the connectivity of the docking components and then connects the communication module. Only after the communication module is connected does the charging input voltage appear. The presence detection circuit, combined with the first and second output control circuits, not only achieves adaptive charging current distribution but also effectively avoids ineffective charging due to poor contact and the attendant charging risks.

[0062] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0063] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A dual-battery online balancing charging system for drones, characterized by: The system includes a shelter, a charging control board, a docking assembly and a battery control board; The docking assembly includes a cabin-side docking piece, a drone-side docking piece, and a position detection circuit; when the cabin-side docking piece and the drone-side docking piece are fully in contact, the position detection circuit sends a drone position signal to the charging control board; The charging control board, the cabin-side docking piece, and the docking signal generating circuit are installed in the cabin; the battery control board and the drone-side docking piece are installed on the drone, and the battery control board includes a first battery control unit and a second battery control unit; The charging control board includes an MCU module, a first communication module, a second communication module, a first output control circuit, and a second output control circuit; the first output control circuit and the first communication module are connected to the first battery of the drone through the first battery control board, and the second output control circuit and the second communication module are connected to the second battery of the drone through the second battery control board; The MCU module responds to the drone in-position signal and synchronously sends an inquiry signal to the first communication module and the second communication module to complete the communication interaction with the first battery control board and the second battery control board. After receiving the battery pack power parameters returned by the first battery control board and the second battery control board, the MCU module sends a charging control signal to the first output control circuit and the second output control circuit to adaptively charge the first battery and the second battery based on the preset charging current, so that the first battery and the second battery are adaptively allocated the charging current with power balance as the constraint condition until both reach the slow charging voltage at the same time; The first output control circuit and the second output control circuit have the same structure, and both include a first switch circuit, a switch enabling circuit, a first enabling circuit, a second switch circuit, a second enabling circuit and a power determination circuit; The second switch circuit is connected between the charging input terminal and the charging output terminal; The first switch circuit is connected to the MCU module, receives the charging control signal sent by the MCU module, outputs a first level signal to the switch enable circuit, and the switch enable circuit outputs a second level signal to the first enable circuit to turn on the second enable circuit and the power determination circuit; The second enabling circuit and the power judgment circuit simultaneously compare the charging input voltage and the charging output voltage. When the charging output voltage is lower than the charging input voltage, the second enabling circuit continues to charge the second switching circuit to turn on the second switching circuit until the charging output voltage is higher than the charging input voltage, and the power judgment circuit turns off the second switching circuit.

2. The UAV dual-battery online balancing charging system according to claim 1 is characterized in that: The first switch circuit includes a first transistor, a second transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor; The base of the first transistor is connected to the MCU module through the first resistor on the one hand, and is grounded through the fourth resistor on the other hand. The collector of the first transistor is connected to the charging input terminal through the second resistor and the third resistor in sequence, and the emitter of the first transistor is grounded through the fifth resistor; the base of the second transistor is connected to the connection point of the second resistor and the third resistor, and the emitter of the second transistor is connected to the charging input terminal through the sixth resistor; the collector of the second transistor is grounded through the seventh resistor and the eighth resistor in sequence on the one hand, and is connected to the switch enabling circuit on the other hand.

3. The UAV dual-battery online balancing charging system according to claim 1 is characterized in that: The first enabling circuit uses a first NMOS transistor, the source and drain of the first NMOS transistor are respectively connected in parallel to the input and output of the second enabling circuit and the power determination circuit, the gate of the first NMOS transistor is connected to the output of the switch enabling circuit, and the drain of the first NMOS transistor is connected to the second switch circuit; When the switch enable circuit outputs a second level signal to the gate of the first NMOS transistor, the first NMOS transistor is turned off to turn on the second enable circuit and the power judgment circuit; otherwise, the first NMOS transistor remains in the on state, short-circuiting the second enable circuit and the power judgment circuit while outputting a drain voltage to turn off the second switch circuit.

4. The UAV dual-battery online balancing charging system according to claim 1, characterized in that: The switch enabling circuit includes a ninth resistor, a tenth resistor and a third transistor; the base of the third transistor is connected to the output end of the first switch circuit through the ninth resistor, the collector is connected to the charging input end through the tenth resistor, and the emitter is grounded.

5. The UAV dual-battery online balancing charging system according to claim 1, characterized in that: The second enabling circuit uses a charge pump and a first amplifier, and the power determination circuit uses the second amplifier; the positive electrode of the first amplifier is connected to the charging input terminal, and the negative electrode is connected to the charging output terminal through the first fine-tuning circuit. When the charging input voltage is greater than the charging output voltage, the charge pump continuously charges the second switching circuit to turn on the second switching circuit until the charging output voltage is higher than the charging input voltage; The power determination circuit uses a second amplifier and a second NMOS tube; the drain of the second NMOS tube is connected to the second switch circuit, and the gate is connected to the output end of the second amplifier; the positive electrode of the second amplifier is connected to the charging output end, and the negative electrode is connected to the charging input end through a second fine-tuning circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS tube is turned on and outputs a drain voltage to turn off the second switch circuit.

6. The UAV dual-battery online balancing charging system according to claim 1, characterized in that: The second switch circuit uses a third NMOS transistor and a fourth NMOS transistor; The drain of the third NMOS transistor is connected to the charging output terminal, and the drain of the fourth NMOS transistor is connected to the charging input terminal; the source and gate of the third NMOS transistor and the fourth NMOS transistor are connected to each other, and the gates of both are connected to the output terminals of the first enabling circuit, the second enabling circuit, and the power determination circuit.

7. The UAV dual-battery online balancing charging system according to claim 1, characterized in that: The in-position detection circuit includes a ground terminal, a communication power supply circuit and a charging enabling circuit; The output end of the communication power supply circuit is connected to the communication module on the drone side, and the output end of the charging enabling circuit is connected to the charging input end; The grounding terminal is located on the cabin side docking piece. When the cabin side docking piece is connected to the drone side docking piece, the grounding terminal is grounded and outputs a low-level signal to the MCU module, so that the MCU module starts the communication power supply circuit and provides the first communication module and the second communication module with a working voltage. The first communication module and the second communication module send the battery pack power parameter to the MCU module, and the MCU module starts the charging enable circuit to provide a charging input voltage to the charging input end.

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