Ground-air transient electromagnetic unmanned aerial vehicle battery temperature control method and system

Abstract

The invention belongs to the technical field of ground-air transient electromagnetism detection, and particularly relates to an unmanned aerial vehicle battery temperature control method and system for ground-air transient electromagnetism, and the method comprises the steps: obtaining a turn-off time signal of an emission current of an emission system, enabling the turn-off time signal to be used for synchronously receiving a synchronous collection time signal of the system, and obtaining a turn-on time signal of the emission current of the emission system; calculating a first time period between the starting time signal and the synchronous acquisition time signal; in the first time period, taking a low-frequency alternating current signal as a driving signal of a heating circuit; and taking the high-frequency alternating current signal as a driving signal of the heating circuit in a second time period exceeding the first time period. Through a staged and frequency-divided mode, a magnetic field introduced by temperature control is distinguished from a working frequency band of a ground-air transient electromagnetic detection task, and interference to a target signal is reduced.

Description

Technical Field

[0001] The present application belongs to the field of ground-to-air transient electromagnetic detection technology, and specifically is a method and system for controlling the battery temperature of a drone used for ground-to-air transient electromagnetic. Background Art

[0002] The ground-to-air transient electromagnetic method uses ground transmission and aerial reception to transmit current to the underground medium through a long ground wire, and then an aerial drone equipped with a receiving system captures the secondary field signal when the current is interrupted. By analyzing the different positions of the response curve, the underground electrical distribution can be obtained, thereby realizing the detection of underground anomalies. The ground-to-air transient electromagnetic method has the advantages of both full aviation transient electromagnetic and ground transient electromagnetic. It has the advantages of high safety, low cost, large exploration depth, and low dependence on the surface terrain environment. It can quickly explore large areas. According to research and applications at home and abroad, the ground-to-air transient electromagnetic method has become an important means in the field of energy exploration and resource exploration.

[0003] At present, the power source of drones used for ground-to-air transient electromagnetic detection generally relies on lithium batteries. Due to the characteristics of lithium batteries themselves, in low-temperature environments, the activity of battery electrolytes decreases and the resistance of solid-liquid membranes increases, resulting in reduced battery charging and discharging efficiency and shortened flight time. At the same time, the battery output power is insufficient and it is difficult to meet the power requirements of motors and other equipment under high loads, which will weaken the power of drones, reduce flight speed, and affect climbing capabilities. In summary, in order to overcome the impact of low-temperature environments on flight missions, it is particularly important to take insulation measures for drone batteries. The existing temperature control measures use DC heaters to heat the batteries. When working, the DC heaters will generate low-frequency magnetic fields. This low-frequency magnetic field will interfere with the ground-to-air transient electromagnetic detection mission, resulting in a decrease in the signal-to-noise ratio, thereby affecting the accuracy of detection. Summary of the invention

[0004] The embodiments of the present application provide a method and system for controlling the temperature of a drone battery for ground-to-air transient electromagnetic (GATEM), which solves the problem of interference with GATEM detection caused by the low-frequency magnetic field generated during the temperature control process.

[0005] This application is implemented in this way. A first aspect provides a ground-to-air transient electromagnetic UAV battery temperature control method, the method comprising: Acquiring a turn-off time signal of a transmitting current of a transmitting system for use in synchronizing a synchronous acquisition time signal of a receiving system; Acquire a start time signal of a transmitting current of a transmitting system; Calculating a first time period between a start time signal and a synchronous acquisition time signal; In the first time period, a low-frequency AC signal is used as a driving signal of the heating circuit; In a second time period exceeding the first time period, a high-frequency AC signal is used as a driving signal for the heating circuit.

[0006] Further, the current battery temperature at any monitoring time within the first time period is obtained, and compared with a preset target temperature, and when the current battery temperature reaches the preset target temperature, the driving signal of the heating circuit is stopped; When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature does not reach the preset target temperature, the second time period is started.

[0007] Furthermore, the frequency range of the signal received by the receiver is obtained, and the maximum frequency in the frequency range is used as a reference, and a high-frequency AC signal is selected from frequencies higher than the reference.

[0008] Furthermore, the frequency range of the high-frequency AC signal is 100KHz-500KHz.

[0009] Furthermore, it also includes: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate fuzzy control correction value according to real-time temperature difference and temperature difference change rate; Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

[0010] The second aspect provides a ground-to-air transient electromagnetic UAV battery temperature control system, including: a main control unit, which obtains a shutdown time signal of the transmission current of the transmission system for synchronizing the synchronous acquisition time signal of the receiving system, and obtains a start time signal of the transmission current of the transmission system; calculates a first time period between the start time signal and the synchronous acquisition time signal; within the first time period, uses a low-frequency AC signal as a driving signal for a heating circuit; in a second time period exceeding the first time period, uses a high-frequency AC signal as a driving signal for the heating circuit.

[0011] Furthermore, the main control unit is also used for: Obtaining the current battery temperature at any monitoring time within the first time period, comparing it with a preset target temperature, and stopping the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature; When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature does not reach the preset target temperature, the second time period is started.

[0012] Furthermore, the main control unit is also used for: The frequency range of the signal received by the receiver is obtained, the maximum frequency of the frequency range is used as a reference, and a high-frequency AC signal is selected from frequencies higher than the reference.

[0013] Furthermore, the main control unit is also used for: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate fuzzy control correction value according to real-time temperature difference and temperature difference change rate; Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

[0014] Furthermore, a driving circuit is included, for driving the heater according to the driving signal; The driving circuit comprises: A dual-channel DDS frequency synthesizer for generating a low-frequency AC signal or a high-frequency AC signal according to a driving signal; A radio frequency switch, used for selecting to open or close the output channel of the dual-channel DDS frequency synthesizer according to a control signal of a main control unit; A voltage-controlled gain amplifier, used for adjusting the amplitude of the AC signal output by the dual-channel DDS frequency synthesizer according to the control signal of the main control unit; A power amplifier is used to amplify the power of an AC signal.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: By dividing the process into stages and frequencies, the magnetic field introduced by temperature control is distinguished from the working frequency band of the ground-to-space transient electromagnetic detection mission, thereby reducing interference with the target signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of a method for controlling battery temperature of a drone for ground-to-air transient electromagnetic provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a drone battery temperature control system for ground-to-air transient electromagnetic provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of the thermal insulation shell of the battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present application more clear, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0018] The ground-to-air transient electromagnetic detection is carried by a drone in the air. The transmitting system transmits current to the underground medium through a long wire on the ground. The receiving system on the drone then captures the secondary field signal when the current is interrupted. By analyzing the different positions of the response curve, the underground electrical distribution can be obtained, thereby realizing the detection of underground anomalies. When used in cold areas, in order to improve the endurance, the battery is heated by a heater, but an additional low-frequency magnetic field is introduced, which affects the received signal.

[0019] Based on the above problems, the core idea of ​​the embodiments of the present application is to use low-frequency AC signals and high-frequency AC signals in stages. When the receiving system does not start receiving signals, low-frequency AC signals are used to achieve a more uniform heating effect through low-frequency heating. When the receiving system collects signals, high-frequency AC signals are used to distinguish the frequency from the frequency range of the signals received by the receiving system. In subsequent signal processing, the high-frequency signals are removed to avoid affecting the ground-to-air transient electromagnetic detection signals.

[0020] See also Figure 1 As shown, a ground-to-air transient electromagnetic drone battery temperature control method according to an embodiment of the present application includes: S101 obtains a turn-off time signal of a transmitting current of a transmitting system for synchronizing a synchronous acquisition time signal of a receiving system, and obtains a turn-on time signal of a transmitting current of the transmitting system; The turn-off time signal of the transmitting current of the transmitting system is controlled by the controller of the ground-to-space transient electromagnetic system, and the turn-off time signal of the transmitting current is obtained by collecting the transmitting current through the controller. The turn-off time signal of the transmitting current can be obtained from the controller by synchronizing the ground-to-space transient electromagnetic system, or the turn-off time signal of the transmitting current of the transmitting system can be obtained by calculating the transmitting current of the transmitting system; The synchronous acquisition time signal of the receiving system refers to the synchronization process between the receiving system and the transmitting system. Since the data processing of the ground-to-air transient electromagnetic detection must be based on the data extracted at the moment when the transmitting current of the transmitting system is turned off to zero, the transmitting system and the receiving system must be strictly synchronized. At present, the most commonly used synchronization method for ground-to-air transient electromagnetic detection is the synchronization of the GPS synchronization module, and its synchronization accuracy can reach the ns level. The receiving system is in the waiting state for acquisition after powering on, and it starts to collect signals only after receiving the rising edge of the 1pps second pulse sent by the GPS synchronization module.

[0021] S102 calculates a first time period between the start time signal and the synchronous acquisition time signal; S103: In the first time period, a low-frequency AC signal is used as a driving signal for the heating circuit; Steps S102 and S103 can be performed simultaneously regardless of the time sequence, that is, when the start time signal is obtained and it is detected whether the receiving system starts collecting data, there is a certain time difference between the start time signal and the synchronous collection signal.

[0022] In the first time period, the low-frequency AC signal is used as the driving signal of the heating circuit. In the first time period, the low-frequency AC signal is used as the driving signal of the heating circuit, which does not mean that the driving signal of the heating circuit is started only after the first time period has been judged to be completed. Instead, it refers to the duration of the low-frequency AC signal as the driving signal of the heating circuit.

[0023] The frequency range of low-frequency AC signals may overlap with the frequency range of received signals. Since low-frequency AC signals have high heating uniformity, deep penetration, strong stability, and low loss, in the first time period, low-frequency AC signals are used to ensure that the innermost part of the battery can also be heated, that is, the heating uniformity is good, avoiding the use of high-frequency AC signals to heat only the surface or shallow part of the battery.

[0024] S104: In a second time period exceeding the first time period, a high-frequency AC signal is used as a driving signal for a heating circuit.

[0025] The second time period here refers to the time period for heating using a high-frequency AC signal as the driving signal of the heating circuit. The start time is the moment when the first time period ends, that is, the moment when the receiving system starts to receive the signal. During the period when the receiving system receives the signal, the frequency range of the high-frequency AC signal is staggered with the frequency range of the received signal, and in order to quickly end the second time period, it is necessary to select a suitable frequency. When it does not overlap with the frequency range of the received signal, it is also necessary to provide heating efficiency and end as soon as possible. Ending as soon as possible can further reduce the impact on the received signal.

[0026] The above-mentioned staged heating method through low-frequency AC signals and high-frequency AC signals realizes uniform heating of the inside of the battery, and during the period when the receiving system receives the signal, the magnetic field introduced by the temperature control is adjusted to a high frequency to distinguish it from the working frequency band of the receiving system, thereby reducing interference with the target signal.

[0027] In one embodiment, the current battery temperature at any monitoring time within the first time period is obtained and compared with a preset target temperature. When the current battery temperature reaches the preset target temperature, the driving signal of the heating circuit is stopped.

[0028] Since the first time period is not zero, the current battery temperature at each moment needs to be continuously monitored during the first time period, and compared with the preset target temperature, and the stop time of the heating circuit is determined through this comparison.

[0029] The current battery temperature can be collected by a temperature sensor on the battery surface. The preset target temperature is the optimal operating temperature determined based on the battery life.

[0030] When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature has not reached the preset target temperature, the second time period is started. The maximum value of the first time period here refers to the moment when the synchronous acquisition time signal is consistent, that is, the receiving system is started to collect signals. When the current battery temperature has not reached the preset target temperature, the low-frequency AC signal is used as the driving signal for the heating circuit.

[0031] In one embodiment, it is necessary to obtain the frequency range of the signal received by the receiver, and take the maximum frequency of the frequency range as a reference, and select a high-frequency AC signal from the frequencies higher than the reference. The frequency range of the signal received by the receiver can be determined based on empirical values, or based on the collected historical data, and the frequency that is valuable for signal processing can be determined from the collected historical data to determine the frequency range. In order to avoid affecting the received signal. The frequency of the selected high-frequency AC signal should be higher than the frequency range of the received signal and can have a good heating effect. In one embodiment, after a large number of experiments and calculations, the frequency range of the high-frequency AC signal is between 100KHz-500KHz.

[0032] In one embodiment, the frequency and amplitude of the low-frequency AC signal and the frequency and amplitude of the high-frequency AC signal are dynamically adjusted. The method of dynamic adjustment includes: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate the correction value of fuzzy control based on the real-time temperature difference and temperature difference change rate. Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

[0033] The above process needs to be performed within the frequency range of the low-frequency AC signal or the frequency of the high-frequency AC signal.

[0034] The control parameter K can be controlled by the fuzzy control method based on the preset control rule library according to the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature. p , K i , K d Dynamic adjustments are made and control signals are output. The preset control rule library is based on expert experience.

[0035] The current battery temperature is expressed as , the preset target temperature is expressed as .

[0036] Calculate the real-time temperature difference between the current battery temperature and the preset target temperature and the rate of change of temperature difference , call the preset control rule library, according to the real-time temperature difference and the rate of change of temperature difference Generate correction amount , , (in, is the correction value of the proportional term coefficient, is the correction value of the integral term coefficient, is the correction value of the differential term coefficient), and is substituted into the following formula to calculate the control parameters: , , , where , , are the coefficients of proportional term, integral term and differential term respectively, are the gain coefficients of each correction amount respectively.

[0037] Control Signal The calculation formula is: .

[0038] Take the first temperature difference threshold as , the second temperature difference threshold is . When , the maximum allowable value of the output control signal, the gain coefficients are: , , ; When , the gain coefficients are: , ; When , the gain coefficients are: .

[0039] when When , the heating is finished.

[0040] See also Figure 2 As shown, a ground-to-air transient electromagnetic drone battery temperature control system provided in an embodiment of the present application is compared with the ground-to-air transient electromagnetic drone battery temperature control method provided in the above embodiment, and includes: The main control unit obtains the turn-off time signal of the transmitting current of the transmitting system for synchronizing the synchronous acquisition time signal of the receiving system, and obtains the turn-on time signal of the transmitting current of the transmitting system; calculates the first time period between the turn-on time signal and the synchronous acquisition time signal; within the first time period, uses the low-frequency AC signal as the driving signal of the heating circuit; in the second time period exceeding the first time period, uses the high-frequency AC signal as the driving signal of the heating circuit.

[0041] In one embodiment, the main control unit is further used for: Obtaining the current battery temperature at any monitoring time within the first time period, comparing it with a preset target temperature, and stopping the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature; When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature does not reach the preset target temperature, the second time period is started.

[0042] In one embodiment, the main control unit is further used for: The frequency range of the signal received by the receiver is obtained, the maximum frequency of the frequency range is used as a reference, and a high-frequency AC signal is selected from frequencies higher than the reference.

[0043] In one embodiment, the main control unit is further used for: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate fuzzy control correction value according to real-time temperature difference and temperature difference change rate; Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

[0044] In one embodiment, a driving circuit is used to drive the heater according to a control signal of a main control unit; The driving circuit includes: a dual-channel DDS frequency synthesizer, which is used to generate a low-frequency AC signal or a high-frequency AC signal according to a driving signal; a radio frequency switch, which is used to select to open or close the output channel of the dual-channel DDS frequency synthesizer according to a control signal of a main control unit; a voltage-controlled gain amplifier, which is used to adjust the amplitude of the AC signal output by the dual-channel DDS frequency synthesizer according to the control signal of the main control unit, and a D / A converter is arranged between the voltage-controlled gain amplifier and the main control unit, which is used to receive the control voltage digital signal output by the main control unit and convert it into a control voltage analog signal for controlling the voltage-controlled gain amplifier; and a power amplifier, which is used to amplify the power of the AC signal.

[0045] In one embodiment, the main control unit waits for the ground-to-air transient electromagnetic transmitting system to complete the shutdown of the transmitting current, and uses the GPS synchronization signal emitted by the GPS synchronization module of the synchronous receiving system as a synchronous acquisition time signal. When the GPS synchronization signal is not detected, that is, the receiving system is in a waiting state for acquisition, the RF switch is controlled to switch the output channel of the dual-channel DDS frequency synthesizer to one channel, and the dual-channel DDS frequency synthesizer outputs a low-frequency AC signal with a frequency of, for example, 500 Hz to the voltage-controlled gain amplifier, and the driving circuit uses the 500 Hz low-frequency AC signal as the driving signal; when the GPS synchronization signal is detected, that is, the receiving system is in an acquisition state, the RF switch is controlled to switch the output channel of the dual-channel DDS frequency synthesizer to another channel, and the dual-channel DDS frequency synthesizer outputs a high-frequency AC signal with a frequency of, for example, 200 KHz to the voltage-controlled gain amplifier, and the driving circuit uses the 200 KHz high-frequency AC signal as the driving signal.

[0046] In one embodiment, the battery surface temperature is collected by a temperature sensor. The temperature sensor is not limited to any type. For example, a platinum resistance temperature sensor is used. The battery surface temperature collected by the temperature sensor is conditioned by a signal conditioning circuit and then output to a main control unit. The signal conditioning circuit may include a rectifier bridge, an amplifier connected to the rectifier bridge, a voltage follower connected to the amplifier, and an A / D converter connected to the voltage follower. The analog signal is converted into a digital signal through the A / D converter and output to the main control unit.

[0047] See also Figure 3 As shown, in one embodiment of the present application, the battery is disposed in a heat-insulating housing, and the heat-insulating housing includes a detachable housing cover ( Figure 3 (not shown in the figure), the side and bottom of the heat preservation shell include a heat conducting layer 4, a heat insulating layer 2 and a protective shell 1 from the inside to the outside, the cavity of the heat preservation shell serves as a battery mounting slot 5, the bottom of the heat preservation shell is provided with a battery power external interface 6, the flexible film heater 3 is embedded in the two inner cavities of the heat insulating layer 2 and the heat conducting layer 4, and a temperature sensor 7 is provided on any side. The heater is a flexible film heater 3 in the two inner cavities of the heat insulating layer 2 and the heat conducting layer 4 of the heat preservation shell, which is used to heat the battery surface.

[0048] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A ground-to-air transient electromagnetic drone battery temperature control method, characterized in that: The method includes: The turn-off time signal of the transmitting current of the transmitting system is obtained to synchronize the synchronous acquisition time signal of the receiving system, and the turn-on time signal of the transmitting current of the transmitting system is obtained; Calculating a first time period between a start time signal and a synchronous acquisition time signal; In the first time period, a low-frequency AC signal is used as a driving signal of the heating circuit; In a second time period exceeding the first time period, a high-frequency AC signal is used as a driving signal for the heating circuit.

2. The method for controlling the battery temperature of a ground-to-air transient electromagnetic drone according to claim 1 is characterized in that: Obtaining the current battery temperature at any monitoring time within the first time period, comparing it with a preset target temperature, and stopping the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature; When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature does not reach the preset target temperature, the second time period is started.

3. The method for controlling the battery temperature of a ground-to-air transient electromagnetic drone according to claim 1 is characterized in that: The frequency range of the signal received by the receiver is obtained, and the maximum frequency of the frequency range is used as a reference, and a high-frequency AC signal is selected from frequencies higher than the reference.

4. The method for controlling the battery temperature of a ground-to-air transient electromagnetic drone according to claim 1 is characterized in that: The frequency range of the high-frequency AC signal is: 100KHz-500KHz.

5. The method for controlling the battery temperature of a ground-to-air transient electromagnetic drone according to claim 1 is characterized in that: Also includes: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate fuzzy control correction value according to real-time temperature difference and temperature difference change rate; Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

6. A ground-to-air transient electromagnetic drone battery temperature control system, characterized in that: include: The main control unit obtains the turn-off time signal of the transmitting current of the transmitting system for synchronizing the synchronous acquisition time signal of the receiving system, and obtains the turn-on time signal of the transmitting current of the transmitting system; A first time period between the start-up time signal and the synchronous acquisition time signal is calculated; within the first time period, a low-frequency AC signal is used as a driving signal for the heating circuit; in a second time period exceeding the first time period, a high-frequency AC signal is used as a driving signal for the heating circuit.

7. The ground-to-air transient electromagnetic drone battery temperature control system according to claim 6 is characterized in that: The main control unit is also used for: Obtaining the current battery temperature at any monitoring time within the first time period, comparing it with a preset target temperature, and stopping the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature; When the maximum value of the first time period is reached at any monitoring moment and the current battery temperature does not reach the preset target temperature, the second time period is started.

8. The ground-to-air transient electromagnetic drone battery temperature control system according to claim 6 is characterized in that: The main control unit is also used for: The frequency range of the signal received by the receiver is obtained, the maximum frequency of the frequency range is used as a reference, and a high-frequency AC signal is selected from frequencies higher than the reference.

9. The ground-to-air transient electromagnetic drone battery temperature control system according to claim 6 is characterized in that: The main control unit is also used for: Calculate the real-time temperature difference and temperature difference change rate between the current battery temperature and the preset target temperature; Generate fuzzy control correction value according to real-time temperature difference and temperature difference change rate; Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters; According to the control signal, the frequency, amplitude or heating time of the driving signal is adjusted.

10. The ground-to-air transient electromagnetic drone battery temperature control system according to claim 6 is characterized in that: Also included is a driving circuit for driving the heater according to the driving signal; The driving circuit comprises: A dual-channel DDS frequency synthesizer for generating a low-frequency AC signal or a high-frequency AC signal according to a driving signal; A radio frequency switch, used for selecting to open or close the output channel of the dual-channel DDS frequency synthesizer according to a control signal of a main control unit; A voltage-controlled gain amplifier, used for adjusting the amplitude of the AC signal output by the dual-channel DDS frequency synthesizer according to the control signal of the main control unit; A power amplifier is used to amplify the power of an AC signal.

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