Non-magnetic thermal control circuit of spacecraft

Abstract

The invention discloses a non-magnetic thermal control circuit for a spacecraft. The non-magnetic thermal control circuit comprises a logic control circuit, a band-pass filter, a multiplier, an amplifier, a power amplification circuit and a blocking circuit, the logic control circuit outputs a square wave signal with the frequency of 100KHz, and then the square wave signal with the frequency of 100kHz is conditioned into a sine wave with the frequency of 100kHz and the amplitude of about 5V through a band-pass filter; after the sine wave signal is amplified by a multiplier and an amplifier, a sine wave with a set amplitude and an invariable frequency is generated; then the power driving capability is enhanced through the power amplification circuit, the direct current component is removed through the direct current blocking circuit, a sine wave driving signal with the same positive area and negative area, the specific amplitude and the frequency of 100 Khz is finally output to heat a heater, and the signal achieves magnetic field counteracting and non-magnetic thermal control in each sine wave period. According to the invention, the magnetic field detection result can be ensured during thermal control management of the whole satellite.

Description

Technical Field

[0001] The present invention belongs to the technical field of spacecraft thermal control, and in particular relates to a non-magnetic thermal control circuit for spacecraft. Background Art

[0002] With the continuous deepening of geomagnetic detection and space magnetic field detection research, in recent years, a number of scientific research satellites have been launched continuously. The functions achieved are to obtain information on different layers of the Earth system in the region by detecting geomagnetic anomaly areas, study the origin and evolution of the geomagnetic field and the geomagnetic reversal mechanism, draw high-precision and high-resolution lithospheric geomagnetic maps, provide basic data for resource surveys, and obtain high-energy electron information in the inner radiation belt above specific areas to serve aerospace safety and space weather forecasting and research.

[0003] During their operation in space, magnetic field detection satellites face a complex space environment, so they need to use thermal control technology to control the temperature of satellite equipment and structures so that they can operate within the required temperature range and ensure the normal operation of the spacecraft. However, magnetic field detection satellites are usually equipped with high-precision magnetic field detection payloads such as CDSM scalar magnetometers, VFM vector magnetometers, and ASC high-precision star sensors, which are very sensitive to magnetic field changes. Traditional thermal control technology controls the MOS tube switch, uses DC voltage to heat the heater, and collects and analyzes the temperature at the same time, controls the on and off of the MOS tube in the heating circuit, thereby achieving thermal control management. During the thermal control management process, this method will generate magnetic field interference of tens of nT or even stronger, which will be directly captured by the high-precision magnetic field detection payload, affecting the magnetic detection results.

[0004] In order to solve the problem of magnetic field interference introduced by traditional thermal control methods and affect the magnetic detection results, a non-magnetic thermal control method based on sinusoidal wave heating was designed. During the thermal control management of the satellite, the uncontrollable magnetic field interference generated at a distance of 3 cm from the VFM is no more than 0.3nT, thus ensuring the magnetic field detection results. Summary of the invention

[0005] In view of this, the present invention provides a spacecraft non-magnetic thermal control circuit, which can ensure that the uncontrollable magnetic field interference generated at a distance of 3 cm from the VFM is no more than 0.3nT when the whole satellite is performing thermal control management, thereby ensuring the magnetic field detection results.

[0006] The technical solution for implementing the present invention is as follows:

[0007] A non-magnetic thermal control circuit for a spacecraft, comprising a logic control circuit, a bandpass filter, a multiplier, an amplifier, a power amplifier circuit and a DC isolation circuit;

[0008] The logic control circuit outputs a square wave signal with a frequency of 100KHz, and then the 0~5V100kHz square wave signal is conditioned into a sine wave with a frequency of 100kHz and an amplitude of about 5V through a bandpass filter; the sine wave signal is amplified by a multiplier and an amplifier to generate a sine wave with a set amplitude and constant frequency; then the power driving capability is enhanced by a power amplifier circuit, and the DC component is removed by a DC isolation circuit, and finally a sine wave drive signal with equal positive and negative areas, a specific amplitude, and a frequency of 100Khz is output to heat the heater. This signal achieves magnetic field cancellation in each sine wave cycle, thereby realizing magnetic-free thermal control.

[0009] Furthermore, during the thermal control process, the changes in thermal control signals are collected as feedback information for the logic control device, thereby achieving real-time closed-loop dynamic adjustment and ensuring the accuracy of thermal control and temperature control.

[0010] Furthermore, the square wave signal is 4 kinds of square wave signals, which are divided into two groups of signals, the two groups of signals have a phase difference of 90°, and the two signals in the same group have a phase difference of 180°.

[0011] Furthermore, the amplification factor of the sine wave amplitude is determined by the logic control device according to actual use requirements.

[0012] Furthermore, the amplifier is composed of two-stage totem poles, LC filtering and a transformer, and the inductor and transformer used in the amplifier are both non-magnetic components.

[0013] Compared with the traditional thermal control circuit, the present invention has the following beneficial effects:

[0014] 1. By outputting a sine wave with equal positive and negative areas to heat the heater, the magnetic field is offset during the forward and reverse heating process, achieving magnetic-free thermal control. This not only realizes the thermal control management of the entire satellite, but also ensures the accuracy of the magnetic field detection mission results.

[0015] 2. The output sinusoidal thermal control signal can change the output amplitude and frequency according to different thermal control management requirements and magnetic detection sampling frequency to adapt to magnetic detection satellites in different application scenarios.

[0016] 3. Under the condition of equal power thermal control management, in order to reduce the power requirement of the sine wave output on the power supply, the square wave signal before the sine wave modulation output is designed into four types, divided into 2 groups of signals. The two groups of signals have a phase difference of 90°, and the two signals in the same group have a phase difference of 180°, which reduces the power output loss caused by the superposition effect of the sine wave output and improves energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the non-magnetic thermal control circuit of the present invention.

[0018] Figure 2 This is a schematic diagram of the square wave generating circuit.

[0019] Figure 3 This is a timing diagram of four square waves.

[0020] Figure 4 This is the block diagram of the sine wave output and amplification circuit.

[0021] Figure 5 This is the block diagram of the amplifier and DC isolation. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0023] The present invention provides a spacecraft non-magnetic thermal control circuit, such as Figure 1 As shown, it includes a logic control circuit, a bandpass filter, a multiplier, an amplifier, a power amplifier circuit and a DC isolation circuit. Taking the realization of 8-way sinusoidal wave heating non-magnetic thermal control as an example, firstly, 4 square wave signals are output through the logic control circuit, each module is divided into 8 channels, and then the main and standby kneading is performed through the driver chip and then output to the sinusoidal wave generating circuit for sharing; the design block diagram is shown in Figure 2 shown.

[0024] In order to reduce the power requirement of the sine wave output on the power supply, four square wave signals are designed and divided into two groups of signals. The phase difference between the two groups of signals is 90°. The phase difference between the two signals in the same group is 180°, which reduces the power output loss caused by the superposition effect of the sine wave output. Figure 3 shown.

[0025] After the above square wave is output, a sine wave with a specific amplitude is output through a sine wave generating circuit and an amplifier circuit, and the block diagram is as follows: Figure 4 As shown in the figure: Using the AM bandpass filter circuit, the 0-5V 100kHz square wave is conditioned into a 100kHz, peak-to-peak sine wave of about 5V. The square wave is the input waveform and the sine wave is the output waveform.

[0026] After the sine wave is output by the multiplier, it is boosted, amplified, and the DC component is removed by the amplifier and the DC isolation circuit. The amplifier consists of a two-stage totem pole, an LC filter, and a transformer. The inductor and transformer used in the amplifier must be purchased as non-magnetic components. A DC isolation capacitor is designed at the output end of the transformer to remove the DC component and ensure that the positive and negative areas of the output sine wave are equal, so as to heat the heater, realize non-magnetic thermal control, and ensure the magnetic field detection results of the spacecraft. At the same time, during the operation, the sinusoidal output voltage is divided and subtracted as a feedback signal for thermal control management. The circuit block diagram is shown below. Figure 5 shown.

[0027] Through the above method, a sinusoidal thermal control signal with equal positive and negative areas, variable amplitude and frequency of 100kHz is output, thereby realizing magnetic-free thermal control of the magnetic detection satellite, and solving the problem that the traditional DC thermal control method cannot be applied to magnetic detection satellites. After experimental comparison, the magnetic field interference of the traditional DC thermal control magnetic field measurement result is tens of nT, and the magnetic field interference of the magnetic field measurement result of the magnetic-free thermal control method of the present invention is less than 0.3nT, which has obvious advantages.

[0028] The solution proposed in this invention focuses on realizing non-magnetic thermal control of the entire satellite by controlling the heating plate with a sine wave, thereby ensuring the accuracy of the magnetic detection mission. The designed and implemented sine wave thermal control management circuit has the following key points, thereby realizing non-magnetic thermal control on this basis:

[0029] 1) The positive and negative areas of the output sine wave waveform are equal, thus ensuring the magnetic field cancellation effect during thermal control of opposite phases within one cycle.

[0030] 2) Considering that the sampling frequency of the magnetic field of the space by the magnetic detection satellite is usually in the hundreds of hertz level, in order to ensure that the magnetic field interference generated by the thermal control is offset in a very short time when the whole satellite is performing magnetic field detection, and is not sampled by the magnetic field detection of the whole satellite, the sinusoidal wave thermal control frequency output in this design is 100kHz, which is much higher than the magnetic field sampling frequency of the whole satellite. At the same time, this high-frequency AC thermal control method can also improve the temperature control accuracy of the whole satellite.

[0031] 3) The output sine wave has adjustable amplitude and is designed to be no less than 40V. Under the condition of equal power, the driving current is reduced to reduce the impact on the magnetic field;

[0032] 4) Before the sine wave drive signal is output, a capacitor must be used to isolate the DC component to remove it.

[0033] 5) Under the condition of equal power thermal control management, in order to reduce the power requirement of the sine wave output on the power supply, the square wave signal before the sine wave modulation output is designed into four types, divided into 2 groups of signals. The two groups of signals have a phase difference of 90°, and the two signals in the same group have a phase difference of 180°, which reduces the power output loss caused by the superposition effect of the sine wave output and improves energy utilization.

[0034] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A spacecraft non-magnetic thermal control circuit, characterized in that: It includes a logic control circuit, a bandpass filter, a multiplier, an amplifier, a power amplifier circuit and a DC isolation circuit; The logic control circuit outputs a square wave signal with a frequency of 100KHz, and then the 0-5V 100kHz square wave signal is conditioned into a sine wave with a frequency of 100kHz and an amplitude of about 5V through a bandpass filter; the sine wave signal is amplified by a multiplier and an amplifier to generate a sine wave with a set amplitude and a constant frequency; then the power driving capability is enhanced by a power amplifier circuit, and the DC component is removed by a DC isolation circuit, and finally a sine wave drive signal with equal positive and negative areas, a set amplitude, and a frequency of 100Khz is output. The sine wave drive signal is used for heater heating, and the sine wave drive signal achieves magnetic field cancellation in each sine wave cycle to achieve non-magnetic thermal control.

2. The spacecraft non-magnetic thermal control circuit according to claim 1, characterized in that: During the thermal control process, the changes in thermal control signals are collected as feedback information for the logic control device, thereby achieving real-time closed-loop dynamic adjustment and ensuring the accuracy of thermal control and temperature control.

3. The spacecraft non-magnetic thermal control circuit according to claim 1, characterized in that: The square wave signals include four types of square wave signals, which are divided into two groups of signals. The phase difference between the two groups of signals is 90°, and the phase difference between the two signals in the same group is 180°.

4. The spacecraft non-magnetic thermal control circuit according to claim 1, characterized in that: The amplification factor of the sine wave amplitude is determined by the logic control device according to actual usage requirements.

5. The spacecraft non-magnetic thermal control circuit according to any one of claims 1 to 4, characterized in that: The amplifier consists of two-stage totem poles, LC filtering and a transformer. The inductors and transformers used in the amplifier are non-magnetic components.

Images