Unmanned aerial vehicle double-battery online balanced charging system

Abstract

The invention discloses a dual-battery online balanced charging system for an unmanned aerial vehicle. The dual-battery online balanced charging system comprises a square cabin, a charging control panel, a butt joint assembly and a battery control panel, the charging control panel comprises an MCU module, a first communication module, a second communication module, a first output control circuit and a second output control circuit. And the MCU module sends a charging control signal to the first output control circuit and the second output control circuit, and carries out self-adaptive charging on the first battery and the second battery at the same time based on a preset charging current, so that the first battery and the second battery distribute the charging current in a self-adaptive manner by taking electric quantity balance as a constraint condition until the first battery and the second battery reach slow charging voltage at the same time. In the charging process, current distribution is automatically completed by a hardware circuit, the current automatically flows to the low-electric-quantity battery pack, and real-time monitoring and intervention of software are not needed, so that the problems of on-line charging and balanced charging of the batteries are effectively solved, and automatic charging and balanced charging of the batteries on the two sides are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV power management, and particularly to a UAV dual-battery online balancing charging system. Background Art

[0002] With the progress of technology and the growth of market demand, UAV technology has made remarkable development in the past few years. The application fields of UAVs have been continuously expanding, gradually penetrating from the initial military use into the civilian market, including multiple fields such as logistics transportation, agricultural monitoring, environmental protection, security patrol, film shooting, and disaster relief. In order to meet the high requirements of these diverse applications for flight duration, load capacity, and system reliability, many UAV manufacturers have started to adopt a dual-battery system for power supply.

[0003] The introduction of the dual-battery system has brought significant advantages to UAVs. Firstly, it can significantly improve the flight duration of UAVs, enabling them to stay in the air for a longer time and complete more complex tasks. Secondly, the dual-battery system enhances the load capacity of UAVs, enabling them to carry more equipment or goods to meet the requirements of different application scenarios. In addition, the dual-battery system also increases the redundancy of the system, improving the reliability and safety of UAVs. When one battery fails, the other battery can continue to supply power to ensure the normal operation of the UAV.

[0004] However, the dual-battery system also faces some technical challenges in charging and management. Traditional UAV battery charging systems usually use an independent charging box for charging. This method requires removing the battery from the UAV and inserting it into the charging box for charging. The charging box can perform balanced charging on the dual batteries to ensure that the voltages and capacities of the two batteries are consistent, thereby ensuring the availability and safety of the batteries. However, this charging method requires manual intervention, the operation is cumbersome, and in the case of frequent use, it may cause wear on the battery interface. In addition, the process of removing the battery may also increase the downtime of the UAV, affecting its usage efficiency.

[0005] Another common charging method is battery online charging, that is, charging can be carried out without removing the battery. Although this method simplifies the operation process, since the batteries are usually charged independently, it is easy to cause the problem of voltage mismatch between the two batteries. Voltage mismatch will cause the UAV to still be unable to take off when the total battery power is sufficient, because the battery management system will detect a too large voltage difference and thus prevent the UAV from starting. Voltage mismatch not only affects the normal operation of the UAV, but may also have an adverse impact on the battery life and performance.

[0006] The invention with the publication number CN117977737A discloses an in-vehicle dual-battery automatic charging control system and method, which uses a charging interface to charge two batteries simultaneously. By monitoring the power of the dual batteries in real time, it preferentially charges the battery with a lower power. However, this invention requires a current-limiting resistor and needs to detect the battery power in real time during the charging process, with high software and hardware requirements.

[0007] The invention with the 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 access different types of chargers. The charging circuits are used to connect between the charging interface circuit and the battery, and different charging circuits are used to adapt to different types of chargers. Among them, when a charger is connected to the charging interface circuit, the main control circuit is used to: identify the type of the charger and select a charging circuit suitable for the type of the charger to charge the battery. This invention also monitors the remaining power of multiple batteries and continuously adjusts the charging current of each charging circuit to complete the simultaneous charging of multiple batteries, with high software and hardware requirements.

[0008] In addition, there are also certain deficiencies in the online charging method of such batteries in terms of charging efficiency and safety. Due to the lack of an effective voltage balancing mechanism, the battery may be overcharged or undercharged during the charging process, affecting the battery life and performance. Overcharging may cause the battery to overheat, increasing the safety risk, while undercharging may cause the battery capacity to be insufficient, affecting the endurance of the drone.

[0009] Therefore, how to achieve online balanced charging of drone batteries without increasing the operation 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 drone batteries. During the charging process, the hardware circuit automatically completes the current distribution, and the current automatically flows to the battery pack with a lower power, without real-time monitoring and intervention of software. Thus, it effectively solves the problems of battery online charging and balanced charging, and realizes automatic charging and bilateral battery balanced charging.

[0011] To achieve the above technical purpose, the technical solution adopted by the present invention is: An online balanced charging system for dual drone batteries, the system includes a shelter, a charging control board, a docking component and a battery control board; The docking component includes a shelter-side docking piece, a drone-side docking piece and a positioning detection circuit; when the shelter-side docking piece and the drone-side docking piece are in full contact, the positioning detection circuit sends a drone positioning signal to the charging control board; The charging control board, the side docking component of the shelter, and the docking signal generating circuit are installed inside the shelter; the battery control board and the side docking component of the drone are installed on the drone. 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, in response to the drone in-position signal, synchronously sends inquiry signals 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 charging control signals to the first output control circuit and the second output control circuit, and adaptively charges the first battery and the second battery simultaneously based on a preset charging current, so that the first battery and the second battery adaptively allocate the charging current with the power balance as a constraint condition until both reach the slow charge voltage. 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 quantity judgment 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 enabling circuit, and the switch enabling circuit outputs a second level signal to the first enabling circuit to turn on the second enabling circuit and the power quantity judgment circuit; the second enabling circuit and the power quantity 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 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, and the power quantity judgment circuit turns off the second switch circuit.

[0012] Further, the first switch circuit includes a first triode, a second triode, 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 triode is connected to the MCU module through a first resistor on the one hand and grounded through a fourth resistor on the other hand. The collector of the first triode is connected to the charging input terminal through a second resistor and a third resistor in sequence, and the emitter of the first triode is grounded through a fifth resistor. The base of the second triode is connected to the connection point between the second resistor and the third resistor, and the emitter of the second triode is connected to the charging input terminal through a sixth resistor. The collector of the second triode is grounded through a seventh resistor and an eighth resistor on the one hand and connected to the switch enabling circuit on the other hand. Further, 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 terminal and the output terminal of the second enabling circuit and the power quantity judgment circuit. The gate of the first NMOS transistor is connected to the output terminal of the switch enabling circuit, and the drain of the first NMOS transistor 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, the first NMOS transistor is turned off to turn on the second enabling circuit and the power quantity judgment circuit; otherwise, the first NMOS transistor remains in the conducting state, short-circuits the second enabling circuit and the power quantity judgment circuit, and outputs a drain voltage to turn off the second switch circuit.

[0013] Further, the switch enabling circuit includes a ninth resistor, a tenth resistor, and a third triode. The base of the third triode is connected to the output terminal of the first switch circuit through the ninth resistor, the collector is connected to the charging input terminal through the tenth resistor, and the emitter is grounded. Further, the second enabling circuit uses a charge pump and a first amplifier, and the power quantity judgment circuit uses a 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 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. The power quantity judgment circuit uses a second amplifier and a second NMOS transistor. The drain of the second NMOS transistor is connected to the second switch circuit, and the gate is connected to the output terminal of the second amplifier. The positive electrode of the second amplifier is connected to the charging output terminal, and the negative electrode is connected to the charging input terminal through a second fine-tuning circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS transistor is turned on, and a drain voltage is output to turn off the second switch circuit.

[0014] Further, 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 sources and gates of the third NMOS transistor and the fourth NMOS transistor are all 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 quantity judgment circuit.

[0015] Further, the in-place detection circuit includes a ground terminal, a communication power supply loop, and a charging enable circuit; The output end of the communication power supply loop is connected to the communication module on the drone side, and the output end of the charging enable circuit is connected to the charging input end; The ground terminal is located on the docking component on the shelter side. After the docking component on the shelter side is connected to the docking component on the drone side, the ground terminal is grounded, and a low-level signal is output to the MCU module, causing the MCU module to activate the communication power supply loop to provide operating voltage for the first communication module and the second communication module. The first communication module and the second communication module send the battery pack power parameter to the MCU module, and the MCU module activates the charging enable circuit to provide charging input voltage to the charging input end.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the dual-battery online balancing charging system for drones of the present invention optimizes the battery power supply system. By preferentially charging the low-power battery, it ensures the voltage balance of the dual batteries and avoids take-off problems caused by voltage mismatch.

[0017] Second, the dual-battery online balancing charging system for drones of the present invention effectively solves the problems of battery online charging and balancing charging, realizes automatic charging and bilateral battery equalization charging, supports higher load capacity, and meets diverse application requirements.

[0018] Third, the dual-battery online balancing charging system for drones of the present invention avoids overcharging or undercharging that may occur during battery charging, improves the battery life and performance, extends the flight time of the drone, enhances the endurance ability, significantly improves the use efficiency and safety of the drone, and opens up new possibilities for the development and application of drone technology.

[0019] Fourth, the dual-battery online balancing charging system for drones of the present invention does not rely on software communication and can achieve adaptive current distribution by means of a hardware circuit. It has good stability and low computing energy consumption. By reasonably setting the constant-current charging current, it ensures that the high current generated instantaneously due to unstable connection during charging will not damage the battery, reduces the charging risk, and is especially suitable for charging drones in multi-vibration areas.

[0020] Fifth, for the dual-battery online balancing charging system for drones of the present invention, the switches and enable signals of the entire circuit depend on voltage division or comparison of the charging input voltage. Therefore, there is no need to configure an additional control power supply for the charging system. While improving the system safety, it can also be adapted to most charging piles on the market, and is especially suitable for quickly distributing power to drones during field operations. Description of the Drawings

[0021] Figure 1 Schematic diagram of the docking method between the cabin of the dual-battery online balancing charging system for drones of the present invention and the drone; Figure 2 Schematic diagram of the structure of the charging control board; Figure 3 Schematic diagram of the module framework of the output control circuit; Figure 4 Schematic diagram of the implementation circuit of the first switch circuit; Figure 5 Schematic diagram of the implementation circuits of the switch enabling circuit, the first enabling circuit, the second switch circuit, the second enabling circuit, and the power judgment circuit; Figure 6 Schematic diagram of the in-place detection circuit, where (a) represents the signal schematic diagram of the connector, (b) represents the A-channel in-place detection protection circuit, and (c) represents the B-channel in-place detection protection circuit. Detailed implementation manners

[0022] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0023] Refer to Figure 1 , the present invention discloses a dual-battery online balancing charging system for drones, and the system includes a cabin, a charging control board, a docking component, and a battery control board.

[0024] The docking component includes a cabin-side docking piece, a drone-side docking piece, and an in-place detection circuit; when the cabin-side docking piece and the drone-side docking piece are in full contact, the in-place detection circuit sends a drone-in-place signal to the charging control board.

[0025] The charging control board, the cabin-side docking piece, and the docking signal generation 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.

[0026] Refer to Figure 2 , 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.

[0027] The MCU module responds to the UAV in-place signal, synchronously sends inquiry signals to the first communication module and the second communication module, completes the communication interaction with the first battery control board and the second battery control board, and after receiving the battery pack power parameters returned by the first battery control board and the second battery control board, sends a charging control signal to the first output control circuit and the second output control circuit, and adaptively charges the first battery and the second battery simultaneously based on a preset charging current, so that the first battery and the second battery adaptively allocate the charging current with the power balance as a constraint condition until both reach the slow charge voltage at the same time.

[0028] See Figure 3 , 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 judgment circuit; the second switch circuit is connected between the charging input end and the charging output end.

[0029] 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 enabling circuit, and the switch enabling circuit outputs a second-level signal to the first enabling circuit to turn on the second enabling circuit and the power judgment 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 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, and the power judgment circuit turns off the second switch circuit.

[0030] Different from the prior art that uses software to detect the battery pack power in real time and adjusts the charging voltages 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, set the charging current according to the collected battery pack power parameters, and then the first output control circuit and the second output control circuit will automatically allocate the charging current, first charge the battery with lower power, continuously reduce the power difference between the two batteries, adaptively allocate the charging current after the power difference reaches a certain degree, charge the two at different speeds simultaneously, and continue to reduce the power difference between the two batteries until their powers are balanced and both reach the slow charge voltage at the same time.

[0031] See Figure 4, the first switching circuit includes a first triode T1, a second triode 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 triode T1 is connected to the MCU module through the first resistor R1 on the one hand and grounded through the fourth resistor R4 on the other hand. The collector of the first triode 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 triode T1 is grounded to GND through the fifth resistor R5; the base of the second triode T2 is connected to the connection point between the second resistor R2 and the third resistor R3, and the emitter of the second triode T2 is connected to the charging input terminal VCC_IN through the sixth resistor R6; the collector of the second triode T2 is grounded to GND through the seventh resistor R7 and the eighth resistor R8 in sequence on the one hand and connected to the switch enabling circuit on the other hand.

[0032] See Figure 5 , the switch enabling circuit includes a ninth resistor R9, a tenth resistor R10, and a third triode T3; the base of the third triode T3 is connected to the output terminal V1 of the first switching 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.

[0033] The first enabling circuit uses a first NMOS transistor M1. The source and drain of the first NMOS transistor M1 are respectively connected in parallel to the input and output terminals of the second enabling circuit and the power quantity judging circuit. The gate of the first NMOS transistor M1 is connected to the output terminal of the switch enabling circuit, and the drain of the first NMOS transistor M1 is connected to the second switching 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 quantity judging circuit; otherwise, the first NMOS transistor M1 remains in the conducting state, shorting the second enabling circuit and the power quantity judging circuit while outputting the drain voltage to turn off the second switching circuit.

[0034] Suppose the voltages of the first battery and the second battery 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, both the first triode and the second triode in the first switch circuit are turned off. The voltage signal received by the switch enabling circuit is 0, the gate voltage of the first NMOS transistor is at a low voltage, the first NMOS transistor is turned on, shorting the second enabling circuit and the power judgment circuit. At the same time, the drain voltage is at a high voltage, turning off the second switch circuit and cutting off the charging input terminal and the charging output terminal. Both the first battery and the second battery are in an uncharged state. When the MCU module sends a charging control signal (about 3.3V) to the first switch circuit of the first output control circuit and the second output control circuit, the first triode and the second triode are turned on in sequence. After dividing the charging input voltage, it is sent to the switch enabling circuit for boosting. The gate voltage of the first NMOS transistor is at a high voltage, the first NMOS transistor is turned off, and the second enabling circuit and the power judgment circuit start to work. The second enabling circuit and the power judgment circuit adaptively control the on / off of the second switch circuit according to the remaining power of the first battery and the second battery.

[0035] 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 trimming 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. The power judgment 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 switch 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 trimming circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS transistor M2 is turned on, and the drain voltage is output to turn off the second switch circuit.

[0036] 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 sources and gates of the third NMOS transistor M3 and the fourth NMOS transistor M4 are all 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 judgment circuit.

[0037] Figure 5 The third amplifier IOP3 in it is used to detect the negative input potential on the MOSFET source (SOURCE) pin and quickly pull down the gate (GATE) voltage to the source level, thereby turning off the MOSFET and achieving electrical isolation between the load and the negative input.

[0038] After 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, in order to increase the sensitivity of the two amplifiers, a millivolt-level voltage fine-tuning circuit is added to the negative input terminal of the first amplifier IOP1 and the positive input terminal of the second amplifier IOP2 respectively, which is used to generate different output voltage signals for the charging circuit and the power judgment circuit respectively when the battery is about to be fully charged. The specific value of the voltage fine-tuning circuit and the buck-boost mode can be set according to the actual charging requirements. 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 switching 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 uses the method of alternating charge and discharge of capacitors and switches to convert the low voltage into a high voltage. In this example, by boosting the input voltage, the output terminal is connected to the gate of the NMOS transistor, so that the gate voltage of the NMOS transistor is greater than the source voltage, keeping the NMOS transistor in the open state.

[0039] To achieve adaptive charging current distribution, the MCU module first calculates the maximum charging current during the constant current period (such as 10A) according to the feedback battery parameters. The voltage at the charging input terminal starts to increase continuously from 0V. When the voltage at the charging input terminal exceeds 20V, the second switching circuit of the first output control circuit is turned on. At this time, since the voltage at the charging input terminal is still less than the voltage of the second battery, the second switching circuit of the second output control circuit has not been turned on yet. Therefore, only the first battery starts to charge at a charging speed of 10A. To maintain the constant current, the charging input voltage continues to rise until it exceeds 40V, and the second switching circuit of the second output control circuit is turned on. The first battery and the second battery start to charge simultaneously, and the charging current is automatically distributed according to the voltage difference. In the present invention, during the constant current stage, the total current value on the two charging circuits remains unchanged. Even if the charging circuit of one of the batteries is disconnected due to environmental factors or problems with the drone itself, the other battery will not be damaged due to the instantaneously applied high current, so that the balanced charging system of the present invention is particularly suitable for charging drones in harsh environments or with poor charging pile connection performance, such as outdoor environments with a lot of vibrations. In addition, the charging process of the present invention does not need to rely on software communication and can achieve adaptive current distribution by means of a hardware circuit, with good stability and low calculation energy consumption.

[0040] For the maximum charging current during the constant current period, it can be determined according to the actual application scenario. For example, select the smaller rated charging current of the two battery packs as the maximum charging current to ensure that the high current generated instantaneously due to unstable connection during charging will not damage the battery. In practical applications, the drone can be charged while powered off or while on standby. When charging while on standby, a charging judgment program can be set in the drone. If one or both of the connection terminals are disconnected due to external vibration, the charging pile can be reconnected after the environment stabilizes, and the balance charging can be carried out again, thus reducing the workload of the staff. At the same time, the built-in program has high stability and low dependence on the communication quality between the drone and the shelter. Even if the RS485 communication modules of the two are disconnected, the charging process can be automatically restored on the basis of ensuring charging safety.

[0041] As one of the preferred examples, Figure 6 is a schematic diagram of the in-place detection circuit, as Figure 6 shown, where (a) represents the signal schematic diagram of the connector, (b) represents the A-channel in-place detection protection circuit, and (c) represents the B-channel in-place detection protection circuit. Diodes D15 and D24 are ESD protection diodes, while diodes D14 and D23 are used for voltage protection to prevent damage to the MCU GPIO caused by the high voltage of the external interface. Their anodes are respectively connected to the voltage source VDD_3V3 through resistors R34 and R29 to obtain a working voltage of 3.3V. The A_GND_CTRL signal and the B_GND_CTRL signal, as the signals protected by the diodes, are directly connected to the MCU. When the devices are plugged in, the levels of the A_GND_CTRL# signal and the B_GND_CTRL# signal of the docking interface will be pulled low, and the A_GND_CTRL signal and the B_GND_CTRL signal are also pulled to a low level through the unidirectional conductivity of the diodes. In practical applications, after the external interface is inserted, the cathodes of diodes D14 and D23 are grounded. By detecting the potential change of the MCU GPIO, it is detected whether the target battery is in place. After the MCU detects that the target battery is in place, the communication power supply circuit is turned on to supply power to the battery-side communication board. After the battery-side communication board is powered on, data exchange with the charging control board is completed through the RS485 signal, and finally the battery charging circuit is turned on.

[0042] The in-place detection circuit first confirms the connectivity of the docking part. On this basis, the communication module is turned on, and the charging input voltage will be provided only after the communication module is turned on. The in-place detection circuit combines the first output control circuit and the second output control circuit, which can not only achieve the adaptive distribution of the charging current, but also effectively avoid the ineffective charging caused by poor contact and the subsequent charging risks.

[0043] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0044] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A dual-battery online balancing charging system for an unmanned aerial vehicle, characterized in that The system includes a shelter, a charging control board, a docking component, and a battery control board; The docking component includes a shelter-side docking piece, a drone-side docking piece, and a positioning detection circuit; when the shelter-side docking piece and the drone-side docking piece are in full contact, the positioning detection circuit sends a drone-in-position signal to the charging control board; The charging control board, the shelter-side docking piece, and the docking signal generation circuit are installed inside the shelter; 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, in response to the drone-in-position signal, synchronously sends inquiry signals 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, and after receiving the battery pack power parameters returned by the first battery control board and the second battery control board, 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 allocate the charging current with the battery power balance as a constraint condition until both reach the slow charge voltage; 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 judgment 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 enabling circuit, and the switch enabling circuit outputs a second level signal to the first enabling circuit to turn on the second enabling circuit and the power judgment 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 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, and the power judgment circuit turns off the second switch circuit.

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

3. The dual-battery online balancing charging system for unmanned aerial vehicles according to claim 1, wherein 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 terminals of the second enabling circuit and the power quantity judgment circuit. The gate of the first NMOS transistor is connected to the output terminal of the switch enabling circuit, and the drain of the first NMOS transistor 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, the first NMOS transistor is turned off to enable the second enabling circuit and the power quantity judgment circuit; otherwise, the first NMOS transistor remains in the conducting state, short-circuits the second enabling circuit and the power quantity judgment circuit, and outputs a drain voltage to turn off the second switch circuit.

4. The drone 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 triode; the base of the third triode is connected to the output terminal of the first switch circuit through the ninth resistor, the collector is connected to the charging input terminal through the tenth resistor, and the emitter is grounded.

5. The dual-battery online balancing charging system for unmanned aerial vehicles according to claim 1, wherein The second enabling circuit uses a charge pump and a first amplifier, and the power quantity judgment circuit uses a 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 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; The power quantity judgment circuit uses a second amplifier and a second NMOS transistor; the drain of the second NMOS transistor is connected to the second switch circuit, and the gate is connected to the output terminal of the second amplifier; the positive electrode of the second amplifier is connected to the charging output terminal, and the negative electrode is connected to the charging input terminal through a second fine-tuning circuit. When the charging output voltage is higher than the charging input voltage, the second NMOS transistor is turned on to output a drain voltage to turn off the second switch circuit.

6. The dual-battery online balancing charging system for unmanned aerial vehicles according to claim 1, wherein 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 sources and gates of the third NMOS transistor and the fourth NMOS transistor are all 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 quantity judgment circuit.

7. The dual-battery online balancing charging system for drones according to claim 1, wherein, The in-place detection circuit includes a grounding terminal, a communication power supply loop, and a charging enabling circuit; The output terminal of the communication power supply loop is connected to the communication module on the drone side, and the output terminal of the charging enabling circuit is connected to the charging input terminal; The grounding terminal is located on the side docking component of the shelter. When the side docking component of the shelter is connected to the side docking component of the UAV, the grounding terminal is grounded, outputting a low-level signal to the MCU module, enabling the MCU module to activate the communication power supply circuit, providing operating voltage to the first communication module and the second communication module. The first communication module and the second communication module send battery pack power parameter to the MCU module, and the MCU module activates the charging enable circuit to provide charging input voltage to the charging input terminal.

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