An Unmanned Aerial Vehicle Battery Temperature Control Method and System for Ground-Air Transient Electromagnetic

Abstract

This application belongs to the technical field of airborne transient electromagnetic detection, and specifically relates to a method and system for temperature control of an unmanned aerial vehicle battery for airborne transient electromagnetic. It includes: obtaining the turn-off time signal of the transmission current of the transmission system to synchronize the synchronous acquisition time signal of the receiving system, and obtaining the turn-on time signal of the transmission current of the transmission system; calculating the first time period between the turn-on time signal and the synchronous acquisition time signal; within the first time period, using a low-frequency alternating current signal as the driving signal of the heating circuit; in the second time period exceeding the first time period, using a high-frequency alternating current signal as the driving signal of the heating circuit. By means of staging and frequency division, the magnetic field introduced by temperature control is distinguished from the working frequency band of the airborne transient electromagnetic detection task, reducing the interference to the target signal.

Description

Technical Field

[0001] This application belongs to the technical field of airborne transient electromagnetic detection, and specifically relates to a method and system for controlling the temperature of an unmanned aerial vehicle (UAV) battery for airborne transient electromagnetic. Background Art

[0002] The airborne transient electromagnetic method uses a ground transmission and an airborne reception method. An electric current is transmitted to underground media through a long ground wire, and then an airborne UAV carrying a reception system captures the secondary field signal when the current is interrupted. By analyzing different positions of the response curve, the underground electrical distribution can be obtained, thereby realizing the detection of underground anomalies. The airborne transient electromagnetic combines the advantages of full-airborne transient electromagnetic and ground transient electromagnetic, and has the advantages of high safety, low cost, large exploration depth, and little dependence on the surface terrain environment, and can quickly explore large areas. According to domestic and foreign research and applications, the airborne transient electromagnetic method has become an important means in the fields of energy exploration and resource exploration.

[0003] Currently, the power source of UAVs used for airborne transient electromagnetic detection generally relies on lithium batteries for power supply. Due to the characteristics of lithium batteries themselves, in a low-temperature environment, the activity of the battery electrolyte decreases and the solid-liquid film resistance increases, resulting in a decrease in the charge and discharge efficiency of the battery and a shortening of the battery life. At the same time, the output power of the battery is insufficient to meet the power requirements of equipment such as motors under high load, causing the power of the UAV to weaken, the flight speed to decrease, and the climbing ability to be affected. To sum up, in order to overcome the influence of the low-temperature environment on the flight mission, it is particularly important to take heat preservation measures for the UAV battery. Existing temperature control measures use a DC heater to supply heat to the battery. When working, the DC heater will generate a low-frequency magnetic field, which will interfere with the airborne transient electromagnetic detection mission, resulting in a decrease in the signal-to-noise ratio and thus affecting the detection accuracy. Summary of the Invention

[0004] A method and system for controlling the temperature of a UAV battery for airborne transient electromagnetic provided by an embodiment of this application solve the problem of interference with airborne transient electromagnetic detection caused by the low-frequency magnetic field generated during the temperature control process.

[0005] This application is implemented as follows

[0006] In a first aspect, a method for controlling the temperature of a UAV battery for airborne transient electromagnetic is provided. The method includes

[0007] Obtaining the turn-off time signal of the transmission current of the transmission system to synchronize the synchronous acquisition time signal of the reception system

[0008] Obtaining the turn-on time signal of the transmission current of the transmission system

[0009] Calculating a first time period between the turn-on time signal and the synchronous acquisition time signal

[0010] During the first time period, a low-frequency alternating current signal is used as the driving signal of the heating circuit;

[0011] During a second time period exceeding the first time period, a high-frequency alternating current signal is used as the driving signal of the heating circuit.

[0012] Furthermore, obtain the current battery temperature at any monitoring moment within the first time period, compare it with a preset target temperature, and stop the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature;

[0013] When any monitoring moment reaches the maximum value of the first time period and the current battery temperature does not reach the preset target temperature, start the second time period.

[0014] Furthermore, obtain the frequency range of the signal received by the receiver, and select a high-frequency alternating current signal from the frequencies higher than the reference based on the maximum frequency of the frequency range.

[0015] Furthermore, the frequency range of the high-frequency alternating current signal is: 100KHz - 500KHz.

[0016] Furthermore, it further includes:

[0017] Calculate the real-time temperature difference and the rate of change of the temperature difference between the current battery temperature and the preset target temperature;

[0018] Generate a correction amount for fuzzy control according to the real-time temperature difference and the rate of change of the temperature difference;

[0019] Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters;

[0020] Adjust the frequency, amplitude or heating time of the driving signal according to the control signal.

[0021] In a second aspect, a temperature control system for an unmanned aerial vehicle battery in a ground-air transient electromagnetic system is provided, including: a main control unit, which obtains the turn-off time signal of the transmission current of the transmission system to synchronize the synchronous acquisition time signal of the reception system, and obtains the turn-on time signal of the transmission current of the transmission system; calculates the first time period between the turn-on time signal and the synchronous acquisition time signal; during the first time period, uses a low-frequency alternating current signal as the driving signal of the heating circuit; during a second time period exceeding the first time period, uses a high-frequency alternating current signal as the driving signal of the heating circuit.

[0022] Furthermore, the main control unit is further configured to:

[0023] Obtain the current battery temperature at any monitoring moment within the first time period, compare it with a preset target temperature, and stop the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature;

[0024] When any monitoring moment reaches the maximum value of the first time period and the current battery temperature does not reach the preset target temperature, the second time period is started.

[0025] Furthermore, the main control unit is further configured to:

[0026] Obtain the frequency range of the received signal of the receiver, and select a high-frequency alternating current signal from the frequencies higher than the reference based on the maximum frequency of the frequency range.

[0027] Furthermore, the main control unit is further configured to:

[0028] Calculate the real-time temperature difference and the temperature difference change rate between the current battery temperature and the preset target temperature;

[0029] Generate a correction amount for fuzzy control according to the real-time temperature difference and the temperature difference change rate;

[0030] Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters;

[0031] Adjust the frequency, amplitude or heating time of the drive signal according to the control signal.

[0032] Furthermore, it further includes a drive circuit for driving the heater according to the drive signal;

[0033] The drive circuit includes:

[0034] A dual-channel DDS frequency synthesizer for generating a low-frequency alternating current signal or a high-frequency alternating current signal according to the drive signal;

[0035] A radio frequency switch for selecting to open or close the output channel of the dual-channel DDS frequency synthesizer according to the control signal of the main control unit;

[0036] A voltage-controlled gain amplifier for adjusting the amplitude of the alternating current signal output by the dual-channel DDS frequency synthesizer according to the control signal of the main control unit;

[0037] A power amplifier for power amplifying the alternating current signal.

[0038] Compared with the prior art, the present application has at least the following beneficial effects:

[0039] By means of a phased and frequency-divided method, the magnetic field introduced by temperature control is distinguished from the working frequency band of the ground-air transient electromagnetic detection task, reducing the interference to the target signal. Description of the Drawings

[0040] Figure 1 It is a flowchart of a method for controlling the temperature of an unmanned aerial vehicle battery for ground-air transient electromagnetic used in an embodiment of the present application;

[0041] Figure 2 Schematic diagram of a UAV battery temperature control system for ground-air transient electromagnetic provided by an embodiment of the present application;

[0042] Figure 3 Schematic diagram of the thermal insulation housing of the battery provided by an embodiment of the present application. Specific embodiments

[0043] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] Ground-air transient electromagnetic detection is carried out by means of being carried by a UAV. An electric current is transmitted to underground media through a long wire on the ground by a transmitting system, and then a receiving system carried by the UAV captures a secondary field signal when the current is interrupted. By analyzing different positions of the response curve, the underground electrical distribution can be obtained, so as to realize the detection of underground anomalies. When used in cold regions, in order to improve the endurance, a heater is used to heat the battery, but an additional low-frequency magnetic field is introduced, thus affecting the received signal.

[0045] Based on the above problems, the core idea of the embodiment of the present application is to use low-frequency alternating current signals and high-frequency alternating current signals in stages. When the receiving system does not start receiving signals, low-frequency alternating current signals are used to achieve a more uniform heating effect through low-frequency heating. When the receiving system collects signals, high-frequency alternating current signals are used to distinguish the frequencies from the frequency range of the signals received by the receiving system. In subsequent signal processing, by removing high-frequency signals, the influence on ground-air transient electromagnetic detection signals is avoided.

[0046] See Figure 1 As shown, a method for controlling the temperature of a UAV battery for ground-air transient electromagnetic of an embodiment of the present application. The method includes:

[0047] S101 Obtain the turn-off time signal of the transmission current of the transmitting system to synchronize the synchronous acquisition time signal of the receiving system, and obtain the turn-on time signal of the transmission current of the transmitting system;

[0048] The turn-off time signal of the transmission current of the transmitting system is controlled by the controller of the ground-air transient electromagnetic system, and this turn-off time signal of the transmission current is obtained by collecting the transmission current through the controller. The turn-off time signal of the transmission current of the transmitting system can be obtained from the controller by synchronizing the ground-air transient electromagnetic system, or can be calculated by collecting the transmission current of the transmitting system.

[0049] 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.

[0050] S102 calculates a first time period between the start time signal and the synchronous acquisition time signal;

[0051] S103: In the first time period, a low-frequency AC signal is used as a driving signal for the heating circuit;

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The above-mentioned method of heating in stages with low-frequency alternating current signals and high-frequency alternating current signals realizes uniform heating inside the battery. During the period when the receiving system receives signals, the magnetic field introduced by temperature control is adjusted to a high frequency, which is distinguished from the working frequency band of the receiving system, thereby reducing interference with the target signal.

[0058] In one embodiment, the current battery temperature at any monitoring moment 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.

[0059] Since the first time period is not zero, during the duration of the first time period, it is necessary to continuously monitor the current battery temperature at each moment and compare it with the preset target temperature. Through this comparison, the stop time of the heating circuit is determined.

[0060] The current battery temperature can be obtained by collecting the temperature on the surface of the battery using a temperature sensor on the battery surface. The preset target temperature is the optimal operating temperature determined according to the battery's endurance time.

[0061] When any monitoring moment reaches the maximum value of the first time period and the current battery temperature has not reached the preset target temperature, the second time period is started. Here, the maximum value of the first time period refers to the moment when the synchronous acquisition time signal is consistent, that is, when the receiving system starts to collect signals. When the current battery temperature has not reached the preset target temperature, a low-frequency alternating current signal is used as the driving signal of the heating circuit.

[0062] In one embodiment, it is necessary to obtain the frequency range of the signals received by the receiver. Based on the maximum frequency of the frequency range, a high-frequency alternating current signal is selected from the frequencies higher than the reference. The frequency range of the signals received by the receiver can be determined according to empirical values, or the frequency range can be determined based on the collected historical data by determining the frequencies valuable for signal processing from the collected historical data. To avoid affecting the received signals, the frequency of the selected high-frequency alternating current signal should be higher than the frequency range of the received signals and be a frequency that can achieve a good heating effect. In one embodiment, through a large number of experiments and calculations, the frequency range of the high-frequency alternating current signal is between 100KHz and 500KHz.

[0063] In one embodiment, the frequency and amplitude of the low-frequency alternating current signal and the frequency and amplitude of the high-frequency alternating current signal are dynamically adjusted. The methods of dynamic adjustment include:

[0064] Calculating the real-time temperature difference and the rate of change of the temperature difference between the current battery temperature and the preset target temperature;

[0065] Generating a correction amount for fuzzy control based on the real-time temperature difference and the rate of change of the temperature difference,

[0066] Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters;

[0067] Adjust the frequency, amplitude or heating time of the drive signal according to the control signal.

[0068] The above process needs to be carried out in the frequency range of the low-frequency AC signal or the frequency of the high-frequency AC signal.

[0069] The control parameters K p 、K i 、K d can be dynamically adjusted by means of fuzzy control based on a preset control rule library according to the real-time temperature difference and the temperature difference change rate between the current battery temperature and the preset target temperature, and a control signal is output. The preset control rule library is obtained based on expert experience.

[0070] Represent the current battery temperature as , and represent the preset target temperature as .

[0071] When , calculate the real-time temperature difference between the current battery temperature and the preset target temperature and the temperature difference change rate . Call the preset control rule library to generate correction amounts 、 、 、 (wherein, is the correction amount of the proportional term coefficient, is the correction amount of the integral term coefficient, is the correction amount of the differential term coefficient) according to the real-time temperature difference and substitute them into the following formula to calculate the control parameters: , , in the formula, 、 、 are the proportional term, integral term and differential term coefficients respectively, are the gain coefficients of each correction amount respectively.

[0072] The calculation formula of the control signal is: .

[0073] Take the first temperature difference threshold as , and the second temperature difference threshold as . When , output the maximum allowable value of the control signal, and the gain coefficients are respectively: , ; When the time is as such, the gain coefficients are respectively: , ; When the time is as such, the gain coefficients are respectively: .

[0074] When , stop heating.

[0075] Refer to Figure 2 As shown, a temperature control system for an unmanned aerial vehicle (UAV) battery of ground-air transient electromagnetic provided by an embodiment of the present application, when understood in comparison with the ground-air transient electromagnetic UAV battery temperature control method provided by the above embodiment, includes:

[0076] A main control unit, which acquires the turn-off time signal of the transmission current of the transmission system to synchronize with the synchronous acquisition time signal of the receiving system, and acquires the turn-on time signal of the transmission current of the transmission system; calculates the first time period between the turn-on time signal and the synchronous acquisition time signal; within the first time period, uses a low-frequency alternating current signal as the driving signal of the heating circuit; in the second time period exceeding the first time period, uses a high-frequency alternating current signal as the driving signal of the heating circuit.

[0077] In one embodiment, the main control unit is further configured to:

[0078] Acquire the current battery temperature at any monitoring moment within the first time period, compare it with a preset target temperature, and stop the driving signal of the heating circuit when the current battery temperature reaches the preset target temperature;

[0079] When any monitoring moment reaches the maximum value of the first time period and the current battery temperature does not reach the preset target temperature, start the second time period.

[0080] In one embodiment, the main control unit is further configured to:

[0081] Acquire the frequency range of the signal received by the receiver, and select a high-frequency alternating current signal from the frequencies higher than the reference based on the maximum frequency of the frequency range.

[0082] In one embodiment, the main control unit is further configured to:

[0083] Calculate the real-time temperature difference and the temperature difference change rate between the current battery temperature and the preset target temperature;

[0084] Generate a correction amount for fuzzy control according to the real-time temperature difference and the temperature difference change rate;

[0085] Update the control parameters of the fuzzy control according to the correction amount, and adjust the control signal according to the control parameters;

[0086] Adjust the frequency, amplitude or heating time of the driving signal according to the control signal.

[0087] In one embodiment, a driving circuit is used to drive a heater according to a control signal of a main control unit.

[0088] The driving circuit includes: 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 for selecting to open or close an output channel of the dual-channel DDS frequency synthesizer according to a control signal of the main control unit; a voltage-controlled gain amplifier for adjusting the amplitude of the AC signal output by the dual-channel DDS frequency synthesizer according to a control signal of the main control unit. A D / A converter is arranged between the voltage-controlled gain amplifier and the main control unit for receiving a control voltage digital signal output by the main control unit and converting it into a control voltage analog signal for controlling the voltage-controlled gain amplifier; a power amplifier for amplifying the power of the AC signal.

[0089] In one embodiment, the main control unit waits for the airborne transient electromagnetic emission system to complete the turn-off of the emission current and synchronously receives a GPS synchronization signal sent by the GPS synchronization module of the receiving system as a synchronous acquisition time signal. When the GPS synchronization signal is not detected, that is, when the receiving system is in a state of waiting for acquisition, the main control unit controls the radio frequency switch to switch the output channel of the dual-channel DDS frequency synthesizer to one channel. 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, when the receiving system is in an acquisition state, the main control unit controls the radio frequency switch to switch the output channel of the dual-channel DDS frequency synthesizer to another channel. 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.

[0090] In one embodiment, the surface temperature of the battery is collected by a temperature sensor. The type of the temperature sensor is not limited. For example, a platinum resistance temperature sensor is used. The surface temperature of the battery collected by the temperature sensor is conditioned by a signal conditioning circuit and then output to the 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 by the A / D converter and output to the main control unit.

[0091] See Figure 3 As shown, in one embodiment of the present application, the battery is arranged in a heat preservation housing. The heat preservation housing includes a detachable housing cover located at the top of the heat preservation housing ( Figure 3(not shown in the figure), the side and bottom of the thermal insulation housing sequentially include a heat conduction layer 4, a heat insulation layer 2, and a protective outer shell 1 from the inside to the outside. The cavity of the thermal insulation housing serves as a battery installation groove 5. A battery power external interface 6 is provided on the bottom surface of the thermal insulation housing. The flexible film heater 3 is embedded in the inner cavities of the two layers of the heat insulation layer 2 and the heat conduction layer 4, and a temperature sensor 7 is provided on any side surface. The heater is the flexible film heater 3 in the inner cavities of the two layers of the heat insulation layer 2 and the heat conduction layer 4 of the thermal insulation housing, and is used to heat the surface of the battery.

[0092] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall 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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