Mooring lighting unmanned aerial vehicle system applied to emergency repair of power transmission and distribution line

Abstract

The invention provides a mooring lighting unmanned aerial vehicle system applied to power transmission and distribution line emergency repair, and belongs to the technical field of lighting. An airborne power supply, a standby battery and a lighting lamp are arranged on a multi-rotor unmanned aerial vehicle; the multi-rotor unmanned aerial vehicle is connected with the ground mooring box through a mooring cable of the mooring automatic take-up and pay-off device; the airborne power supply and the standby battery are connected with the multi-rotor unmanned aerial vehicle, the lighting lamp and the mooring automatic take-up and pay-off device; the flight control unit is connected with the multi-rotor unmanned aerial vehicle and the illumination lamp, and the flight control unit is used for controlling the flight height and direction of the multi-rotor unmanned aerial vehicle and the angle and brightness of the illumination lamp; a ground power supply is arranged in the ground mooring box; the ground power supply is used for transmitting electric energy to the airborne power supply and the standby battery through the mooring cable; and the standby battery is used for supplying power to the multi-rotor unmanned aerial vehicle and the lighting lamp when the airborne power supply cannot supply power. The efficiency of first-aid repair operation is improved, and the requirement for long-time construction operation is met.

Description

Technical Field

[0001] The present invention relates to the technical field of power transmission and distribution line lighting maintenance, and in particular to a tethered lighting drone system used for power transmission and distribution line emergency repair. Background Art

[0002] In the maintenance and inspection process of modern power transmission and distribution lines, the working environment is usually complex, especially during nighttime operations, and traditional lighting equipment often cannot meet the needs of efficient and safe operations. Currently, maintenance personnel mainly rely on headlights for lighting, but this method has many shortcomings:

[0003] (1) Brightness and illumination limitations: The headlights have relatively low illumination and a limited illumination range, making it difficult to cover a large work area. This means that in complex environments, maintenance personnel may not be able to clearly identify surrounding equipment and obstacles, increasing operational risks.

[0004] (2) Insufficient continuous lighting capacity. The battery life of the headlamp is limited. Long-term use will cause the lighting effect to weaken or even go out. This is particularly dangerous when working at night and may cause work interruption or accidents.

[0005] (3) Waste of manpower and material resources. In some cases, maintenance personnel need to frequently adjust the position of the headlights to ensure that the lighting covers the working area, which not only wastes human resources but also reduces work efficiency. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a tethered lighting drone system for emergency repair of power transmission and distribution lines. The present invention has the advantages of efficient lighting, saving manpower and material resources, adaptability to complex environments, rapid response and long-term lighting.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A tethered lighting drone system used for emergency repair of power transmission and distribution lines, comprising: an airborne power supply, a multi-rotor drone, a backup battery, a lighting fixture, a tethered automatic retracting and releasing device, a flight control unit, and a ground tethering box;

[0009] The onboard power supply, the backup battery and the lighting fixture are arranged on the multi-rotor UAV; the multi-rotor UAV is connected to the ground mooring box through the mooring cable of the mooring automatic retracting and releasing device; the onboard power supply and the backup battery are both connected to the multi-rotor UAV, the lighting fixture and the mooring automatic retracting and releasing device; the flight control unit is respectively connected to the multi-rotor UAV and the lighting fixture, and the flight control unit is used to control the flight altitude and direction of the multi-rotor UAV and the angle and brightness of the lighting fixture; a ground power supply is arranged in the ground mooring box; the ground power supply is used to transmit electrical energy to the onboard power supply and the backup battery through the mooring cable; the backup battery is used to power the multi-rotor UAV and the lighting fixture when the onboard power supply cannot supply power.

[0010] Preferably, the ground power supply includes a protection circuit, an EMI filter, a bridge rectifier circuit and a staggered parallel Boost circuit; the output end of the protection circuit is connected to the input end of the EMI filter, the output end of the EMI filter is connected to the input end of the bridge rectifier circuit, and the output end of the bridge rectifier circuit is connected to the staggered parallel Boost circuit.

[0011] Preferably, the bridge rectifier circuit comprises:

[0012] A first bridge rectifier diode Q1, wherein an anode of the first bridge rectifier diode Q1 is connected to an output end of the EMI filter, and a cathode of the first bridge rectifier diode Q1 is connected to a cathode of a second bridge rectifier diode Q2;

[0013] A third bridge rectifier diode Q3, the cathode of the third bridge rectifier diode Q3 is connected to the anode of the first bridge rectifier diode Q1, the anode of the third bridge rectifier diode Q3 is connected to the anode of the fourth bridge rectifier diode Q4; the cathode of the fourth bridge rectifier diode Q4 is connected to the anode of the second bridge rectifier diode Q2.

[0014] Preferably, the staggered parallel Boost circuit comprises:

[0015] A first inductor L1, one end of the first inductor L1 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the first inductor L1 is connected to the anode of the first rectifier diode D1;

[0016] a second inductor L2, one end of the second inductor L2 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the second inductor L2 is connected to the anode of the second rectifier diode D2;

[0017] A first switch tube S1, wherein a first end of the first switch tube S1 is connected to the other end of the first inductor L1, and a second end of the first switch tube S1 is connected to an anode of the fourth bridge rectifier diode Q4;

[0018] A second switch tube S2, wherein a first end of the second switch tube S2 is connected to the other end of the second inductor L2, and a second end of the second switch tube S2 is connected to the second end of the first switch tube S1;

[0019] A capacitor C, one end of the capacitor C is connected to the cathode of the first rectifier diode D1, and the other end of the capacitor C is connected to the second end of the second switch tube S2;

[0020] A resistor R, one end of the resistor R is connected to one end of the capacitor C, and the other end of the resistor R is connected to the other end of the capacitor C.

[0021] Preferably, the tethered automatic retractable wire device comprises: a main control board, a drive module and a tension sensor; the main control board is respectively connected to the drive module and the tension sensor; the tension sensor is used to measure the tension value of the tethered cable; the main control board is used to control the drive module according to the tension value measured by the tension sensor; the drive module is used to control the tethered cable to be recovered or released.

[0022] Preferably, the signal processing process of the main control board includes:

[0023] The analog signal of the tension sensor is obtained through the ADC module embedded in the main control board, and the analog signal is converted into a digital signal to calculate the current tension value T c ; The current tension value T c The calculation formula is:

[0024]

[0025] Among them, ADC is the digital value read by the main control board, V out is the current output voltage of the tension sensor, V max is the maximum voltage output by the tension sensor, V r is the reference voltage of the main control board, T max is the maximum tension value allowed in the system,

[0026] If the current tension value T c When it is less than the set lower limit, the line-reeling operation starts; when it exceeds the set upper limit, the line-releasing operation starts.

[0027] Preferably, the lighting fixture comprises: a steering gear, a steering wheel, a U-shaped bracket and an LED lamp;

[0028] The steering wheel is arranged on the steering gear; the U-shaped bracket is movably connected to the steering wheel; and an LED lamp is also arranged on the U-shaped bracket.

[0029] Preferably, it also includes an alarm device;

[0030] The alarm device is connected to the ground mooring box; the alarm device is used to alarm when it detects that the output power of the power supply is 0.

[0031] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0032] The present invention provides a tethered lighting drone system for power transmission and distribution line emergency repair, comprising: an airborne power supply, a multi-rotor drone, a backup battery, a lighting fixture, a tethered automatic retractable wire device, a flight control unit and a ground tethered box; the airborne power supply, the backup battery and the lighting fixture are arranged on the multi-rotor drone; the multi-rotor drone is connected to the ground tethered box through a tethered cable of the tethered automatic retractable wire device; the airborne power supply and the backup battery are both connected to the multi-rotor drone, the lighting fixture and the tethered automatic retractable wire device; the flight control unit is respectively connected to the multi-rotor drone and the lighting fixture, and the flight control unit is used to control the flight height and direction of the multi-rotor drone and the angle and brightness of the lighting fixture; a ground power supply is arranged in the ground tethered box; the ground power supply is used to transmit electric energy to the airborne power supply and the backup battery through the tethered cable; the backup battery is used to power the multi-rotor drone and the lighting fixture when the airborne power supply cannot supply power. The present invention can provide illumination requirements for nighttime on-site climbing operations of electric power plants, ensure the personal safety of workers performing emergency repairs at night, improve the efficiency of emergency repairs, and meet the requirements of long-term construction operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 A schematic diagram of the structure of a device provided in an embodiment of the present invention;

[0035] Figure 2 A block diagram of the principle of a tethered lighting drone power supply module provided in an embodiment of the present invention;

[0036] Figure 3 An overall design block diagram of the ground power supply provided by an embodiment of the present invention;

[0037] Figure 4 An overall design block diagram of the ground power supply provided by an embodiment of the present invention;

[0038] Figure 5 A schematic diagram of the main circuit of the interleaved parallel Boost PFC provided by an embodiment of the present invention;

[0039] Figure 6 A principle block diagram of average current mode control provided by an embodiment of the present invention;

[0040] Figure 7 A system structure block diagram of an interleaved parallel Buck converter provided in an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of a topological structure of an interleaved parallel Buck converter provided in an embodiment of the present invention;

[0042] Fig. 9 A schematic diagram of gate drive signal and inductor current waveform provided by an embodiment of the present invention;

[0043] Fig.10 A double closed-loop control block diagram of an interleaved parallel Buck converter provided in an embodiment of the present invention;

[0044] Fig.11 A program flow chart of the main function provided by an embodiment of the present invention;

[0045] Fig.12 A program flow chart of ADC interrupt provided by an embodiment of the present invention;

[0046] Fig.13 A voltage outer loop control flow chart provided by an embodiment of the present invention;

[0047] Fig.14 A current inner loop control flow chart provided by an embodiment of the present invention;

[0048] Fig.15 Components of the control system provided by the embodiment of the present invention;

[0049] Fig.16 A signal flow diagram of a control system provided by an embodiment of the present invention;

[0050] Fig.17 A hardware circuit design block diagram provided for an embodiment of the present invention;

[0051] Fig.18 A main program flow chart provided for an embodiment of the present invention;

[0052] Fig.19 A sensor signal acquisition interrupt subroutine provided in an embodiment of the present invention;

[0053] Fig. 20 A signal collection interrupt subroutine for a manually operated motor speed knob provided in an embodiment of the present invention;

[0054] Fig.21 This is a structural diagram of a lighting fixture provided in an embodiment of the present invention.

[0055] Description of reference numerals:

[0056] 1. Onboard power supply; 2. Multi-rotor drone; 3. Backup battery; 4. Lighting fixtures; 4-1. Servo; 4-2. Steering wheel; 4-3. U-shaped bracket; 4-4. LED light; 5. Mooring cable; 6. Ground mooring box. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The purpose of the present invention is to provide a tethered lighting drone system for emergency repair of power transmission and distribution lines, which can provide illumination requirements for on-site high-altitude operations at night, ensure the personal safety of emergency repair workers at night, improve the efficiency of emergency repair operations, and meet the needs of long-term construction operations.

[0059] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] Figure 1 A schematic diagram of the structure of the device provided in the embodiment of the present invention is shown in FIG. Figure 1 As shown, the present invention provides a tethered lighting drone system for power transmission and distribution line emergency repair, comprising: an airborne power supply 1, a multi-rotor drone 2, a backup battery 3, a lighting fixture 4, a tethered automatic retracting and releasing device, a flight control unit and a ground tethering box 6;

[0061] The onboard power supply 1, the backup battery 3 and the lighting fixture 4 are arranged on the multi-rotor UAV 2; the multi-rotor UAV 2 is connected to the ground mooring box 6 through the mooring cable 5 of the mooring automatic retracting and releasing device; the onboard power supply 1 and the backup battery 3 are both connected to the multi-rotor UAV 2, the lighting fixture 4 and the mooring automatic retracting and releasing device; the flight control unit is respectively connected to the multi-rotor UAV 2 and the lighting fixture 4, and the flight control unit is used to control the flight height, direction of the multi-rotor UAV 2 and the angle and brightness of the lighting fixture 4; a ground power supply is arranged in the ground mooring box 6; the ground power supply is used to transmit electrical energy to the onboard power supply 1 and the backup battery 3 through the mooring cable 5; the backup battery 3 is used to power the multi-rotor UAV 2 and the lighting fixture 4 when the onboard power supply 1 cannot supply power.

[0062] The tethered lighting drone system of the present invention is composed of a drone platform, a ground tethered box 6 and an aircraft control unit, specifically including a multi-rotor drone 2, a flight control unit, a power supply module, a tethered automatic retractable wire device, a lighting fixture 4, etc. As shown in the figure, the flight control unit controls the flight height, direction, angle and brightness of the lighting device of the multi-rotor drone 2 to solve the lighting problem at the nighttime emergency repair site of the power supply. The power supply module is responsible for supplying power to the multi-rotor drone 2, the tethered automatic retractable wire device and the lighting device. In order to ensure the safety of the multi-rotor drone 2, the power supply module includes a main power supply and a backup battery 3, wherein the main power supply is composed of a ground power supply and an airborne power supply 1, and the backup battery 3 refers to the battery carried by the drone itself. When the main power supply fails, the power supply system will automatically switch to the backup battery 3. At the same time, when the sensor in the tethered box detects that the output power is 0, the alarm device is triggered to prompt the operator to prepare to land the drone. The tethered automatic retractable wire device can realize the automatic retractable and retractable operation of the tethered cable 5, which greatly improves the automation of the tethered drone system, reduces the workload of the user during use, and improves the safety and convenience of the operation of the tethered drone system. The lighting device mainly includes lighting fixtures 4 and fixtures to provide lighting that meets the conditions for the nighttime power repair work site.

[0063] Design of power supply module

[0064] The present invention adopts a high-voltage direct current power supply technology. The detailed power supply scheme is as follows: the ground power supply converts the generator / 220V, 50Hz AC mains electricity into 400V-700V DC through AC / DC bridge rectification, DC / DC boost circuit (including power factor correction module) and filter circuit, and transmits it to the airborne power supply through the mooring cable. The airborne power supply outputs the 400V-700V DC through the step-down / voltage stabilization circuit and filter circuit to meet the 24V voltage required by the drone and lighting equipment. The output end of the airborne power supply module is connected in parallel with the backup battery to achieve the purpose of real-time protection of the drone safety.

[0065] Among them, the ground power supply mainly realizes EMI filtering, rectification, boost, power factor correction and output filtering functions. In order to realize the boost and power factor correction functions, an interleaved parallel BoostPFC circuit is used as its main circuit, and average current control is used as its control strategy. The voltage outer loop and the current inner loop are used for dual-loop control to control the opening and closing of the switch tube in the Boost circuit, so that its inductor works in CCM mode, and a large-capacity capacitor is used as the filtering circuit of the ground power supply. The airborne power supply mainly realizes the functions of voltage reduction, voltage stabilization and output stability. In order to reduce the weight of the airborne power supply and avoid the use of large devices such as transformers, the present invention adopts an interleaved parallel Buck converter as the main circuit of the airborne power supply, and uses a large-capacity capacitor as the filtering circuit of the airborne power supply, so that it outputs a stable 24V DC.

[0066] Ground power supply

[0067] The overall design block diagram of the ground power supply is as follows: Figure 3 As shown: It is mainly composed of the main circuit and the control circuit. The main circuit includes EMI filter circuit, power frequency bridge rectifier circuit, DC-DC boost circuit, etc. The control circuit mainly includes auxiliary power supply, sampling feedback unit, control unit, etc. The control unit mainly includes PWM wave generator, drive circuit, etc.

[0068] When the ground power supply is working, a single-phase AC 220V input is used. The single-phase AC is first filtered by the EMI filter circuit. The EMI filter network can prevent the harmonics between the rectifier circuit and the power grid from interfering with each other. The second is the bridge rectifier circuit. After the single-phase AC passes through the full-bridge rectifier circuit, a low-voltage DC of about 300V is obtained. The 300V low-voltage DC passes through the DC-DC boost circuit to obtain the expected 400-700V DC high-voltage power.

[0069] In the control part, the DC-DC boost circuit compares the real-time collected output voltage value with the expected output voltage and performs PI adjustment, uses triangle wave modulation to output PWM wave signal, and amplifies the PWM wave signal through the driving circuit to drive the MOS tube to conduct, thereby obtaining the expected voltage value.

[0070] (1) Main circuit of ground power supply

[0071] like Figure 4 As shown, it is the main circuit diagram of the ground power supply, which mainly includes a protection circuit, an EMI filter, a bridge rectifier circuit and an interleaved parallel Boost circuit.

[0072] The output end of the protection circuit is connected to the input end of the EMI filter, the output end of the EMI filter is connected to the input end of the bridge rectifier circuit, and the output end of the bridge rectifier circuit is connected to the staggered parallel Boost circuit.

[0073] Furthermore, the bridge rectifier circuit comprises:

[0074] A first bridge rectifier diode Q1, wherein an anode of the first bridge rectifier diode Q1 is connected to an output end of the EMI filter, and a cathode of the first bridge rectifier diode Q1 is connected to a cathode of a second bridge rectifier diode Q2;

[0075] A third bridge rectifier diode Q3, the cathode of the third bridge rectifier diode Q3 is connected to the anode of the first bridge rectifier diode Q1, the anode of the third bridge rectifier diode Q3 is connected to the anode of the fourth bridge rectifier diode Q4; the cathode of the fourth bridge rectifier diode Q4 is connected to the anode of the second bridge rectifier diode Q2.

[0076] The interleaved parallel Boost circuit comprises:

[0077] A first inductor L1, one end of the first inductor L1 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the first inductor L1 is connected to the anode of the first rectifier diode D1;

[0078] a second inductor L2, one end of the second inductor L2 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the second inductor L2 is connected to the anode of the second rectifier diode D2;

[0079] A first switch tube S1, wherein a first end of the first switch tube S1 is connected to the other end of the first inductor L1, and a second end of the first switch tube S1 is connected to an anode of the fourth bridge rectifier diode Q4;

[0080] A second switch tube S2, wherein a first end of the second switch tube S2 is connected to the other end of the second inductor L2, and a second end of the second switch tube S2 is connected to the second end of the first switch tube S1;

[0081] A capacitor C, one end of the capacitor C is connected to the cathode of the first rectifier diode D1, and the other end of the capacitor C is connected to the second end of the second switch tube S2;

[0082] A resistor R, one end of the resistor R is connected to one end of the capacitor C, and the other end of the resistor R is connected to the other end of the capacitor C.

[0083] Among them, the protection circuit is mainly composed of fuse FU and varistor RV, and its main function is to resist surge current in the system. When a pulse current of non-fault nature occurs in the circuit, the fuse will start to work normally and can also protect the converter from overload. The fuse model is 25A / 600V fuse FU. When a transient overvoltage occurs in the circuit and exceeds its threshold, the varistor will immediately become equivalent to an infinitesimal resistor, absorbing the excess current in the circuit, thereby protecting the subsequent circuit. The model of the varistor is 14D511K.

[0084] The EMI filter is a low-pass filter network. It allows low frequencies to pass, but not high frequencies. The function of the EMI filter is to isolate the switching power supply and the power grid from each other to prevent the high-frequency interference signals generated by each from affecting each other. C1 = C2 = 0.47μF, a 1μF, 630V polypropylene capacitor is selected, and L = 1.2mH.

[0085] Among them, the main circuit of the bridge rectifier circuit and the staggered parallel Boost circuit is as follows Figure 5 As shown in the figure, L1, S1, D1 and L2, S2, D2 respectively form a branch of a phase PFC, and the two inductors L1 and L2 have the same value, the two switch tubes S1 and S2 are the same, and the diodes D1 and D2 are both rectifier diodes, that is, the main circuit topology is composed of two BoostPFC converter structures with exactly the same parameters in parallel, and the two switch tubes are staggered 180° for conduction. The working states of the two converter units are staggered with each other, so the input current is the cumulative sum of the currents flowing through the two inductors, which reduces the current stress of the boost inductor and the power switch tube.

[0086] Because the two boost inductors of the circuit work in an interlaced manner, the phase angle of the ripple current flowing through the inductor is also in an interlaced state. When accumulated, the inductor current ripples of the two branches cancel each other out, so the ripple of the input side current caused by the inductor and the switch tube can be reduced. At the same time, the current flowing through D1 and D2 in the figure constitutes the final output current, and this value is smaller than the peak value, which reduces the ripple current of the output capacitor. Therefore, compared with the traditional Boost PFC converter, the capacity of the EMI filter and the output capacitor can be reduced, and it has better dynamic response characteristics. Among them, C = 1320μF, 6 220μF, 800V electrolytic capacitors are selected, and L1 = L2 = 200μH. The switch tubes S1 and S2 use Cree's SiC MOSFETC2M0025120D, and the diodes D1 and D2 use D5SB80.

[0087] (2) Ground power supply control circuit

[0088] The Boost PFC converter in the present invention adopts average current control, using a voltage outer loop and a current inner loop for dual-loop control. The control method is described below using a conventional Boost PFC converter as an example. Figure 6 As shown. In fact, the control method used in the interleaved PFC structure is essentially the same as the conventional one, except that the two power switches in the interleaved parallel topology are switched on alternately, and the driving signals of the two switches are 180° out of phase. In addition, the current at the input end becomes the sum of the two inductor currents, and the rising and falling trends of the two inductor currents are just opposite, so their superposition reduces the ripple of the current at the input and output ends.

[0089] As Figure 6 As shown, the voltage at the output end is compared with the reference voltage to obtain an error signal, which is then multiplied by the voltage at the input end to obtain a signal, which is used as the current setting signal at the input end of the current controller. Then, the current controller controls the current at the input end according to the given signal, so that the input current and input voltage can maintain the same phase, that is, to achieve a higher power factor. So in summary, the voltage outer loop of the control part allows the voltage at the output end to remain stable; the current loop of the control part allows the input current to be closer to a sine waveform.

[0090] The interleaved parallel Boost PFC control strategy is similar to this. The present invention uses the chip UCC28070 produced by TI to complete the control of the circuit. UCC28070 is a very advanced PFC control chip that integrates two phases that can output 180-degree anti-phase PWM. This interleaved structure can greatly reduce current ripple and simplify the design of the filter. The internal multiplier provides a shared current reference to two independent current amplifiers, ensuring that the two PWM outputs match the average current mode control while maintaining a low-distortion input sinusoidal current.

[0091] The output of the control part is difficult to make the switch tube start working directly because the power value is not enough, so a driving circuit is required. The present invention selects UCC27324 as the driving chip, with a maximum driving current of 4A, which is powered by the auxiliary power supply in the design.

[0092] The present invention adopts interleaved parallel Buck converters as the main circuit of the step-down DC-DC converter. Figure 7 The figure shows the system structure block diagram of the staggered parallel Buck converter. The system is divided into two parts: the main circuit and the control circuit. The main circuit converts 480V-800V DC into a 24V constant DC output. The entire system takes power from the input side and generates DC power of multiple voltage levels for the control board and the main power board through the auxiliary power supply circuit. The control circuit enters the ADC pin of the control chip through multi-channel sampling. After the software program is processed, the drive signal is generated through the EPWM port, and then the four switch tubes are driven to work respectively through the isolation drive circuit. In order to ensure the safe operation of the system, the sampling signal forms a fault signal after the protection circuit and enters the GPIO port of the control chip. Then the control chip determines whether a fault occurs and gives processing such as prohibiting the wave, disconnecting the relay or resetting. The relay control signal of the control chip can determine whether the converter is connected to the load.

[0093] (3) Main circuit of onboard power supply

[0094] The introduction of staggered parallel structure can reduce the current stress of single-circuit components. The inductor currents of each phase can offset each other at the output end, reducing the total output current ripple. The voltage ripple on the output filter capacitor is also reduced accordingly. Therefore, components with lower withstand voltage and smaller size can be selected, which can reduce the cost of the system. At the same time, the system loss is reduced, the heat source is dispersed, and the system efficiency is improved. The two-phase staggered parallel Buck converter topology that introduces the staggered parallel structure into the synchronous rectification Buck converter is as follows Figure 8 As shown, two branches consisting of switch devices and magnetic inductors are connected in parallel to the input power supply and the output load.

[0095] like Fig. 9The figure shows the waveforms of the gate drive signals of the main control tubes Q1 and Q3, the two inductor currents and the total output current in the two-way Buck converter. In the staggered parallel structure, the two-phase drive signals should have the same frequency and be generated staggered. When N phases are staggered in parallel, the phase difference of each phase drive signal is 2π / N. Fig. 9 The phase difference between the two driving signals is π, and the inductor current of each phase corresponds to its driving signal. After being connected in parallel, the two inductor currents converge to the load side. It can be seen that the average value of the total output current is twice that of a single current, and the total ripple current is significantly reduced after offset. At the same time, the output frequency is twice the inductor frequency of each phase. Therefore, when the output frequency is constant, the staggered parallel structure can reduce the switching frequency of each phase, thereby reducing losses and improving efficiency.

[0096] Among them, Cree's SiC MOSFET C2M0025120D is selected as the switch tube of the main circuit. L1 and L2 are selected as inductors with an inductance value of 500μH respectively, and two capacitors with a capacitance value of 40μF are selected in parallel as the output capacitor of the circuit.

[0097] (4) Control circuit of the onboard power supply

[0098] The present invention adopts a voltage outer loop and current inner loop control strategy for staggered parallel Buck converters. The voltage outer loop controls the converter to accurately output the rated voltage, and the current inner loop stabilizes the average current of the two-phase inductor, while improving the response speed of the system. By dividing the current in each phase of the inductor by two paths and controlling the current in the closed loop, the current error of the two paths can be reduced, and the output current value can be better controlled. Fig.10 The figure shows the control block diagram of the staggered parallel Buck converter system. PI controllers are used as compensation devices for the voltage loop and the current loop. The voltage outer loop is compared and adjusted by the PI controller to obtain the reference value of the total output current. The reference value of the current inner loop is obtained after two-way current diversion. After comparison with the sampled inductor current, the switch tube duty cycle signal is obtained through the inner loop PI controller and the PWM modulator. The single-way inductor current value can be output according to the transfer function obtained by modeling. Finally, the two currents are combined to adjust the output voltage of the converter.

[0099] The present invention uses TI's control chip TMS320F28335 to realize digital signal processing. The microcontroller can be applied to highly integrated and high-performance industrial scenarios. F28335 has a 32-bit CPU with a processing speed of up to 150MHz, and is equipped with 18-channel PWM output and a 12-bit, 16-channel ADC. This prototype control system mainly uses DSP's 4-channel EPWM to generate drive signals for four power MOS tubes; 4-channel ADC sampling to collect voltage and current signals and form a closed loop; and 4-channel GPIO interfaces for processing fault information to ensure the safe and reliable operation of the converter.

[0100] like Fig.11 As shown in the figure, it is the program flow chart of the main function. After entering the main function, the system is initialized first, the system is prohibited from entering interrupts, and then the PIE control register is initialized, the timer is initialized, the GPIO port is initialized, the ADC is initialized, the EPWM is initialized, etc. After the initialization operation is completed, the interrupt is allowed to enter and wait for entering the interrupt program. Fig.12 This is the program flow chart of ADC interrupt. When the interrupt flag is read as enabled, voltage and current sampling begins. After multiple samplings are completed and the average value is taken, the interrupt flag is cleared to end the current interrupt. The system also has a timer interrupt. When the software reset, system failure and input voltage requirements are met, the relay can be closed to allow DSP to generate waves, and the system enters the soft start program to start normal operation.

[0101] Depend on Fig.13 It can be seen that after reading the sampled voltage, the error between it and the reference value is calculated and limited. The result obtained by the incremental digital PI regulator algorithm is used as a new round of reference value for the current inner loop after shunting; then Fig.14 It can be seen that after calculating the two-round current errors, the duty cycle value can be obtained according to the same algorithm, and then the EPWM register can be updated to change the duty cycle of the drive signal, so that the dual closed-loop control of the output voltage and the two-phase inductor current can be achieved.

[0102] Design of automatic mooring and retracting device

[0103] 1. Control scheme design

[0104] This automatic retractable wire system is designed based on servo motor and displacement sensor. The control strategy is adjusted by the speed and forward and reverse rotation of the servo motor, and the displacement sensor is used to adjust the control strategy in time. The system is mainly composed of an operation console, a control module, a main control board, and a tension sensor. The following is mainly about the control system such as Fig.15 The components and signal flow diagram shown are as follows Fig.16 As shown in the introduction.

[0105] 1-1. Control system components

[0106] (1) Operation console

[0107] The operating console is mainly composed of the main power supply, torque adjustment knob, main power switch, main power operation indicator, wire-reeling switch, AC input port, and display panel. Its main function is to allow users to set and control relevant control strategies for the automatic wire-reeling and wire-reeling system and power supply system.

[0108] (2) Main control board

[0109] The main control board uses STM32F103C8T6 as the microprocessor for design and development, based on the configuration of the STM32F103C8T6 microprocessor as the main control board and the corresponding interface to meet the development requirements of the project.

[0110] (3) Driver module

[0111] The drive module consists of a DC servo motor, a relay and an electromagnetic clutch. During the wire-reeling process, the electromagnetic clutch is in a closed state, and the DC servo motor mainly drives the reducer to control the torque of the winding drum, rotating it to recycle the cable. During the wire-releasing process, the electromagnetic clutch is disconnected by controlling the relay, and the cable is released by pulling it by the drone, or the cable can be released faster by reversing the motor under manual adjustment.

[0112] (4) Tension sensor

[0113] The tension sensor is mainly composed of a displacement sensor, which is mainly used to measure the tightness of the tethered cable. By analyzing the measurement results of the tightness of the tethered cable, the current requirements for reeling in and releasing the tethered UAV system can be judged, thereby providing auxiliary criteria for the setting of the control strategy.

[0114] The automatic retractable cable system obtains the real-time status of the moored cable through the tension sensor, and then sends the information to the main control module. The main control module analyzes and calculates based on this information, analyzes the control strategy required for the current moored cable, and then outputs the corresponding control signal to the drive module according to the specific strategy, so that the drive module produces a matching action. The signal flow diagram of the automatic retractable cable system is shown in the figure: Fig.16 As shown, the sensor signal, control algorithm and drive signal of the control system will be analyzed respectively below.

[0115] 1-2. Control system signal flow diagram

[0116] (1) Sensor signal

[0117] The displacement sensor measures the cable travel and generates an analog value of the displacement change. The main control board obtains the sensor signal through the ADC interface, collects it as a digital quantity and stores the data in the register.

[0118] (2) Control strategy

[0119] The control algorithm obtains the real-time input signal of the tension sensor from the register, and determines the required retracting and releasing state of the current moored cable by analyzing and calculating the signal, so that the control algorithm generates a corresponding drive signal to control the controlled object.

[0120] (3) Driving signal

[0121] The driving signals transmitted from the main control board to the driving module are divided into two types: PWM signals and DIR signals, which act on the driving module together to control the speed and direction of rotation of the DC servo motor respectively. The main control board outputs a square wave signal with a frequency of 1KHz through the PWM port, and controls the speed of the DC servo motor by adjusting the duty cycle of the signal. The speed of the DC motor is reflected on the winding drum to control the speed of cable retraction and release. The main control board outputs the DIR level signal through any I / O port by opening and closing, which is used to control the forward and reverse rotation of the DC servo motor, that is, to control the direction of the winding drum to determine whether to reel in or unreel.

[0122] 2. Hardware Design

[0123] The hardware aspect includes the system's electronic hardware design and external devices such as motors.

[0124] 2-1. Design parameters and selection of external devices such as motors

[0125] (1) Winding drum design

[0126] The outer diameter of the winding drum is 240mm, the thickness is 3mm, the width is 140mm, and the diameter of the moored cable is 3.5mm. A cable groove is processed at one end of the winding shaft, and the moored cable enters the card slot inside the winding drum through the cable groove. The winding drum realizes the winding and unwinding operation of the moored cable by rotating.

[0127] The minimum inner diameter of the winding drum is Φ1 = 0.15m, the weight of the wire drum is G1 = 8kg, the outer diameter of the drum is Φ2 = 0.18m when the winding reaches 3 layers, the wire length is L = 40m, and the single weight of the cable is g = 0.013kg / m, then the total weight of the cable is:

[0128] G2=L×g=40×0.013=0.52kg

[0129] The maximum weight of the winding drum is:

[0130] G = G2 + G1 = 8 + 0.52 = 8.52 kg

[0131] The total moment of inertia of the winding drum is:

[0132]

[0133] The maximum linear velocity of the winding drum is V = 1.5 m / s, and the time for the speed to accelerate from zero to the maximum speed is t = 2 s.

[0134] The angular velocity of the reel is:

[0135]

[0136] The angular acceleration is:

[0137]

[0138] The reel speed when winding 3 layers is:

[0139]

[0140] The torque is:

[0141] M=I×α=0.058×83.334=4.872N·m

[0142] The motor uses the brushless DC motor 60BL120S25-430 from Beijing Times Chaoqun Electric, with a rated power of 250W, a rated voltage of 48v, a rated current of 7.5A, a no-load current of 0.8A, a rated torque of 0.79N·m, a rated speed of 3000r / min, a no-load speed of 4000r / min, and a pole pair of 4. The reducer uses the Beijing Times Chaoqun PX60 shaft output planetary reducer: reduction ratio 6:1, efficiency 95%, return clearance ≤15, body length 74mm, weight 1kg, and pole number 1. The number of teeth on the reduction sprocket is 16, the number of teeth on the roller sprocket is 50, and the transmission ratio is 16:50. It can provide a torque of 14.81N·m to meet the winding needs of the winding roller.

[0143] 2-2. Main control board module and operation console module

[0144] Based on the above control scheme, the hardware circuit of the designed automatic retractable wire system mainly includes the main control board module, the operation console module and the power supply module. This section mainly introduces the main control board module and the operation console module. The main control board module is the core of the hardware circuit of the automatic retractable wire system. Its design block diagram is as follows Fig.17 shown.

[0145] 3. Software Design

[0146] The control functions mainly realized by the control system software are: the operation console can adjust the speed of the retractable cable, and the automatic retractable cable system can retract and release the tethered cable in accordance with the ascent and descent speed of the UAV. The control software uses a polling-based main program design to collect and process various input signals, and then determines the current operating status of the automatic retractable cable system through calculation and analysis, and finally outputs a control signal to drive the controlled object to achieve the control target.

[0147] In order to improve the steady-state error and response speed of the system, a PID controller is used to dynamically adjust the output. The analog signal of the tension sensor is obtained through the ADC of STM32, converted into a digital signal and the current tension value is calculated.

[0148] For a 12-bit ADC, the sensor current output voltage is V out , the maximum voltage is V max , assuming the microcontroller reference voltage is V r, the digital quantity read from the sensor is ADC, then:

[0149]

[0150] The current actual tension value is T c , the tension can be expressed as:

[0151]

[0152] Current actual tension value T c When the tension is less than the lower limit, the winding operation starts, and when it exceeds the upper limit, the release operation starts. In the winding and release process, PID control is used to more accurately adjust the speed of the motor so that the tension reaches the target value more stably.

[0153]

[0154] In discrete control systems, the integral term can be approximated by the accumulated error, and the differential term can be approximated by the difference of the error. e[n] is the error of the current cycle, n is the number of the sampling moment, and e[n-1] is the error of the previous cycle. e[n] can be expressed as:

[0155] e[n]=T d -T c

[0156] Therefore, in discrete control, the PID control formula can be expressed as:

[0157]

[0158] Set the proportional gain K p =2, integral gain K i =0.1, differential gain K d =0.01, control period dt = 10ms. I[n] and D[N] are the difference between the integral term and the differential term, respectively, which can be expressed as:

[0159] I[n]=I[n-1]+e[n]·dt

[0160]

[0161] Substitute the above set PID parameters into the control formula, and calculate the output signal u[n] through the main loop of the single-chip microcomputer, and then adjust the PWM duty cycle to control the motor speed. The main program flow chart of the cable retractor automatic control system control software is as follows Fig.18 As shown:

[0162] After the system is powered on, the control program on the main control board starts. The specific steps are as follows:

[0163] Step 1: Configure the hardware peripheral functions, including TIM, PWM, ADC, GPIO, and initialization configuration of external interrupts. Then initialize the system parameters to ensure that the automatic retractable wire system is in a safe control state.

[0164] Step 2: Determine whether to enter the main cycle, and then determine whether to perform manual adjustment based on whether the take-up switch is turned on and the torque knob is adjusted.

[0165] Step 3: After entering the automatic mode or manual mode, read the corresponding data signal, judge whether to reel in the line and whether to rotate forward, and execute the logic control process in the corresponding mode in sequence.

[0166] After the execution is completed, repeat the above steps 1 to 3.

[0167] Among them, the subroutines supporting the main program mainly include: sensor signal acquisition interrupt subroutine, manual operation motor speed knob signal acquisition interrupt subroutine, as shown in the figure. Fig.19 , 21 shown.

[0168] 3-1. Sensor signal acquisition interrupt subroutine

[0169] The displacement sensor converts the displacement change into an analog voltage change and transmits it to the main control board. The main control board obtains the sensor signal through the ADC interface, collects it as a digital quantity using the timed interrupt method, and stores the data in the signal storage register after collection. When the control algorithm main program needs to read the current sensor signal, it can read the latest data from the sensor signal storage register. Then, by analyzing and calculating the sensor signal, the required retracting and releasing state of the current mooring cable can be determined.

[0170] 3-2. Manual operation of the motor speed knob signal acquisition interrupt subroutine

[0171] The signal of the manually operated torque adjustment knob is an analog voltage, which is obtained by turning the "torque adjustment knob". The main control board obtains the sensor signal through its own ADC interface, and uses the timed interrupt method to collect it as a digital quantity. After collection, the data is stored in the signal storage register for control algorithm processing and call.

[0172] Lighting design

[0173] like Fig.21As shown, the lighting fixture includes: a steering gear 4-1, a steering wheel 4-2, a U-shaped bracket 4-3 and an LED lamp 4-4; the steering wheel 4-1 is arranged on the steering gear 4-2; the U-shaped bracket 4-3 is movably connected to the steering wheel 4-2; and the U-shaped bracket 4-3 is also provided with an LED lamp 4-4. Demonstratively, the lighting device is mainly composed of a lighting lamp and a fixing device. The lighting lamp is selected from LED (light emitting diode) lamps with outstanding advantages such as long life, mercury-free and environmentally friendly, high luminous efficiency, and color mixing and dimming control. The LED lamp selected in the present invention is 240W, weighs 140g, and is controlled by PWM signal, which can realize stepless dimming. The fixing device is mainly composed of a module quick-plug bracket, a steering gear and a steering wheel. The work site mainly uses the aircraft control unit to control the LED lamp to achieve the purpose of adjusting the LED angle and brightness, realizing a lighting angle without blind spots, and meeting the lighting requirements of the power night repair operation site.

[0174] The beneficial effects of the present invention are as follows:

[0175] (1) The drone’s fixed point, LED lighting angle and brightness can be flexibly controlled through the remote control or ground terminal to achieve a lighting viewing angle without blind spots;

[0176] (2) The power supply system includes a main power supply and a backup power supply. When the main power supply fails, the power supply system will automatically switch to the backup power supply. At the same time, when the sensor in the tethered box detects that the output power is 0, the alarm device is triggered to prompt the operator to prepare to land the drone;

[0177] (3) The moored automatic retractable wire device can automatically or manually realize the retractable wire function, which greatly improves the work efficiency of the staff on site and reduces the risk of electric shock to the staff on site;

[0178] (4) This device can be adapted to any UAV system with a load of more than 3kg, and can add functions such as video and voice communication. It is easy to expand its functions and has a wide range of applications.

[0179] (5) Compared with existing tethered drone systems on the market, the invention has lower costs.

[0180] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0181] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A tethered lighting drone system used for emergency repair of power transmission and distribution lines, characterized in that: include: Onboard power supply, multi-rotor drone, spare battery, lighting fixture, automatic tethering and retracting device, flight control unit and ground tethering box; The onboard power supply, the backup battery and the lighting fixture are arranged on the multi-rotor UAV; the multi-rotor UAV is connected to the ground mooring box through the mooring cable of the mooring automatic retracting and releasing device; the onboard power supply and the backup battery are both connected to the multi-rotor UAV, the lighting fixture and the mooring automatic retracting and releasing device; the flight control unit is respectively connected to the multi-rotor UAV and the lighting fixture, and the flight control unit is used to control the flight altitude and direction of the multi-rotor UAV and the angle and brightness of the lighting fixture; a ground power supply is arranged in the ground mooring box; the ground power supply is used to transmit electrical energy to the onboard power supply and the backup battery through the mooring cable; the backup battery is used to power the multi-rotor UAV and the lighting fixture when the onboard power supply cannot supply power.

2. The tethered lighting drone system for power transmission and distribution line repair according to claim 1 is characterized in that: The ground power supply includes a protection circuit, an EMI filter, a bridge rectifier circuit and a staggered parallel Boost circuit; the output end of the protection circuit is connected to the input end of the EMI filter, the output end of the EMI filter is connected to the input end of the bridge rectifier circuit, and the output end of the bridge rectifier circuit is connected to the staggered parallel Boost circuit.

3. The tethered lighting drone system for power transmission and distribution line repair according to claim 2 is characterized in that: The bridge rectifier circuit comprises: A first bridge rectifier diode Q1, wherein an anode of the first bridge rectifier diode Q1 is connected to an output end of the EMI filter, and a cathode of the first bridge rectifier diode Q1 is connected to a cathode of a second bridge rectifier diode Q2; A third bridge rectifier diode Q3, the cathode of the third bridge rectifier diode Q3 is connected to the anode of the first bridge rectifier diode Q1, the anode of the third bridge rectifier diode Q3 is connected to the anode of the fourth bridge rectifier diode Q4; the cathode of the fourth bridge rectifier diode Q4 is connected to the anode of the second bridge rectifier diode Q2.

4. The tethered lighting drone system for power transmission and distribution line repair according to claim 3 is characterized in that: The interleaved parallel Boost circuit comprises: A first inductor L1, one end of the first inductor L1 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the first inductor L1 is connected to the anode of the first rectifier diode D1; a second inductor L2, one end of the second inductor L2 is connected to the anode of the first bridge rectifier diode Q1, and the other end of the second inductor L2 is connected to the anode of the second rectifier diode D2; A first switch tube S1, wherein a first end of the first switch tube S1 is connected to the other end of the first inductor L1, and a second end of the first switch tube S1 is connected to an anode of the fourth bridge rectifier diode Q4; A second switch tube S2, wherein a first end of the second switch tube S2 is connected to the other end of the second inductor L2, and a second end of the second switch tube S2 is connected to the second end of the first switch tube S1; A capacitor C, one end of the capacitor C is connected to the cathode of the first rectifier diode D1, and the other end of the capacitor C is connected to the second end of the second switch tube S2; A resistor R, one end of the resistor R is connected to one end of the capacitor C, and the other end of the resistor R is connected to the other end of the capacitor C.

5. The tethered lighting drone system for power transmission and distribution line repair according to claim 1 is characterized in that: The tethered automatic retractable wire device comprises: a main control board, a drive module and a tension sensor; the main control board is respectively connected to the drive module and the tension sensor; the tension sensor is used to measure the tension value of the tethered cable; the main control board is used to control the drive module according to the tension value measured by the tension sensor; the drive module is used to control the tethered cable to be recovered or released.

6. The tethered lighting drone system for power transmission and distribution line repair according to claim 5 is characterized in that: The signal processing process of the main control board includes: The analog signal of the tension sensor is obtained through the ADC module embedded in the main control board, and the analog signal is converted into a digital signal to calculate the current tension value T c ; The current tension value T c The calculation formula is: Among them, ADC is the digital value read by the main control board, V out is the current output voltage of the tension sensor, V max is the maximum voltage output by the tension sensor, V r is the reference voltage of the main control board, T max is the maximum tension value allowed in the system, If the current tension value T c When it is less than the set lower limit, the line-reeling operation starts; when it exceeds the set upper limit, the line-releasing operation starts.

7. The tethered lighting drone system for power transmission and distribution line repair according to claim 1 is characterized in that: The lighting fixture includes: a steering gear, a steering wheel, a U-shaped bracket and an LED lamp; The steering wheel is arranged on the steering gear; the U-shaped bracket is movably connected to the steering wheel; and an LED lamp is also arranged on the U-shaped bracket.

8. The tethered lighting drone system for power transmission and distribution line repair according to claim 1 is characterized in that: It also includes an alarm device; The alarm device is connected to the ground mooring box; the alarm device is used to alarm when it detects that the output power of the power supply is 0.

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