Isolated power supply circuit based on industrial unmanned aerial vehicle RTK active antenna

Abstract

The invention discloses an industrial unmanned aerial vehicle RTK active antenna-based isolated power supply circuit, which comprises an input module for receiving an input voltage of an unmanned aerial vehicle system and configuring an input filter network to suppress input power ripples; the isolation conversion module is connected with the input module and comprises a transformer driving circuit, an isolation type transformer and a rectifying circuit, the transformer driving circuit is configured to alternately drive a primary winding of the isolation type transformer in a complementary push-pull mode, the working frequency is dynamically configured through an external resistor, and the resistance value is inversely proportional to the frequency; the primary-secondary winding turn ratio of the isolation type transformer is dynamically adjusted according to the input voltage and the required voltage of the active antenna, and the primary winding and the secondary winding are completely electrically isolated. The rectification circuit is connected with a secondary winding of the isolation type transformer and comprises a diode D1 and a diode D2. According to the isolation type power supply circuit, the lightning stroke surge resistance and the voltage stability of the unmanned aerial vehicle system are obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of UAV power supply, and particularly to an isolated power supply circuit based on an RTK active antenna for industrial UAVs. Background Technique

[0002] In the application of industrial UAVs, the RTK module needs to receive weak satellite signals through an active antenna to achieve high-precision positioning. In the prior art, the power supply of the active antenna mostly uses a non-isolated DC-DC power supply. Most of the existing DC-DC power supplies adopt the BUCK buck topology. This topology mainly includes an energy storage inductor, a MOS tube, and a freewheeling diode (or synchronous rectification MOS). When the MOS tube is turned on, the input power supply stores energy in the inductor through the MOS, and the inductor current rises linearly. When the MOS tube is turned off, the energy stored in the inductor is released to the load through the loop where the freewheeling diode is located, and the inductor current drops linearly. By controlling the duty cycle of the MOS tube conduction, the output voltage can be flexibly controlled. Generally, Vout = D * Vin, where Vout is the output voltage, Vin is the system input voltage, and D is the duty cycle (1 ≥ D ≥ 0). Its input and output share the same ground, and there are the following defects: lightning surge risk. When the active antenna encounters lightning or surge, the energy will be coupled to the main power supply system of the UAV through the non-isolated circuit, resulting in system anomalies or even equipment damage. Electromagnetic interference sensitivity. In a complex electromagnetic environment, non-isolated power supply is vulnerable to common-mode interference, affecting the signal-to-noise ratio. Insufficient dynamic adjustment. The existing solutions lack dynamic response to input voltage fluctuations and load changes, resulting in insufficient output voltage stability.

[0003] To solve the above problems, the present invention proposes an isolated power supply circuit, which realizes efficient and reliable isolated power supply through a push-pull topology, dynamic parameter adjustment, and multiple protection mechanisms. Summary of the Invention

[0004] To solve the technical problems existing in the background technique, the present invention proposes an isolated power supply circuit based on an RTK active antenna for industrial UAVs.

[0005] The isolated power supply circuit based on the RTK active antenna for industrial UAVs proposed by the present invention includes: An input module, which is used to receive the input voltage of the UAV system and configure an input filter network to suppress the input power supply ripple; The isolation conversion module is connected to the input module and includes a transformer drive circuit, an isolation transformer, and a rectification circuit. The transformer drive circuit is configured to alternately drive the primary winding of the isolation transformer in a complementary push-pull manner, and the operating frequency is dynamically configured through an external resistor, with the resistance value being inversely proportional to the frequency. The turns ratio of the primary and secondary windings of the isolation transformer is dynamically adjusted according to the input voltage and the required voltage of the active antenna, and complete electrical isolation is achieved between the primary and secondary. The rectification circuit is connected to the secondary winding of the isolation transformer and includes diode D1 and diode D2, which form a unidirectional current path during the alternating conduction period to convert the secondary alternating current into continuous direct current. The output module is connected to the rectification circuit and includes a multi-stage parallel filter capacitor network for suppressing the output voltage ripple.

[0006] Preferably, the transformer drive circuit includes a first switch channel SW1 and a second switch channel SW2. The first switch channel SW1 and the second switch channel SW2 alternately conduct in a complementary push-pull manner, and the duty cycle D is dynamically inversely adjusted with the input voltage to satisfy: ; where k is a proportionality constant configured through an external resistor network.

[0007] Preferably, the input filter network specifically includes capacitor C1, capacitor C2, and capacitor C3. Capacitor C1, capacitor C2, and capacitor C3 are connected in parallel with each other. One end of capacitor C1 receives the input voltage of the drone system, and the other end of capacitor C1 is grounded.

[0008] Preferably, the transformer drive circuit specifically includes driver U1, resistor R1, resistor R2, resistor R3, resistor R4, and capacitor C7. One end of resistor R1, one end of resistor R2, one end of resistor R3, one end of resistor R4, and one end of capacitor C7 are grounded together. The other end of resistor R1 is electrically connected to the SR terminal of driver U1. The other end of resistor R2 is electrically connected to the SS terminal of driver U1. The other end of resistor R2 is electrically connected to the other end of capacitor C7. The other end of resistor R3 is electrically connected to the DC terminal of driver U1. The other end of resistor R4 is electrically connected to the CLK terminal of driver U1.

[0009] Preferably, it further includes: A soft start module integrated in the transformer drive circuit suppresses the inrush current during power-on by controlling the capacitor charging time, and the soft start time satisfies: where C is the adjustable capacitance value, i.e., capacitor C7; is the driver threshold voltage; I is the constant charging current.

[0010] Preferably, the negative electrodes of the diode D1 and the diode D2 are electrically connected.

[0011] Preferably, the multi-stage parallel filter capacitor network specifically includes a capacitor C4, a capacitor C5, and a capacitor C6. The capacitor C4, the capacitor C5, and the capacitor C6 are connected in parallel with each other. One end of the capacitor C6 outputs a supply voltage. One end of the capacitor C6 is electrically connected to the negative electrode of the diode D1, and the other end of the capacitor C6 is grounded.

[0012] Preferably, the capacitance value range of the capacitor C7 is from 10 nF to 100 μF, and the soft start time can be configured from 1 ms to 100 ms.

[0013] In the present invention, the proposed isolated power supply circuit based on the RTK active antenna of the industrial drone realizes electrical isolation between the input and the output through a push-pull topology, dynamic duty cycle adjustment, and multiple protection designs. It can not only meet the conventional power supply requirements, but also isolate the rest of the circuit of the system when the drone antenna encounters lightning surges, significantly improving the system's lightning surge resistance and voltage stability, and is suitable for the high-precision positioning requirements of drones in complex electromagnetic environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the overall framework of the isolated power supply circuit based on the RTK active antenna of the industrial drone proposed by the present invention; Figure 2 is a schematic diagram of the SA-Net network structure of the isolated power supply circuit based on the RTK active antenna of the industrial drone proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Referring to Figure 1 and Figure 2 , the isolated power supply circuit based on the RTK active antenna of the industrial drone proposed by the present invention includes: An input module, configured to receive the input voltage of the drone system and configure an input filter network to suppress the input power supply ripple.

[0016] In this embodiment, the input filter network specifically includes a capacitor C1, a capacitor C2, and a capacitor C3. The capacitor C1, the capacitor C2, and the capacitor C3 are connected in parallel with each other. One end of the capacitor C1 receives the input voltage of the drone system, and the other end of the capacitor C1 is grounded.

[0017] In this embodiment, the range of the input voltage is specifically 5V - 36V.

[0018] The isolation conversion module is connected to the input module and includes a transformer drive circuit, an isolation transformer, and a rectification circuit. The transformer drive circuit is configured to alternately drive the primary winding of the isolation transformer in a complementary push-pull manner, and the operating frequency is dynamically configured through an external resistor, where the resistance value is inversely proportional to the frequency. The turns ratio of the primary and secondary windings of the isolation transformer is dynamically adjusted according to the input voltage and the required voltage of the active antenna, and complete electrical isolation is achieved between the primary and secondary. The rectification circuit is connected to the secondary winding of the isolation transformer and includes diode D1 and diode D2, which form a unidirectional current path during the alternating conduction period to convert the secondary alternating current into continuous direct current.

[0019] In this embodiment, the transformer drive circuit includes a first switch channel SW1 and a second switch channel SW2. The first switch channel SW1 and the second switch channel SW2 alternately conduct in a complementary push-pull manner, and the duty cycle D is dynamically inversely adjusted with the input voltage , satisfying: where k is a proportionality constant configured through an external resistor network.

[0020] In this embodiment, the transformer drive circuit specifically includes a driver U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a capacitor C7. One end of resistor R1, one end of resistor R2, one end of resistor R3, one end of resistor R4, and one end of capacitor C7 are grounded. The other end of resistor R1 is electrically connected to the SR terminal of driver U1, the other end of resistor R2 is electrically connected to the SS terminal of driver U1, the other end of resistor R2 is electrically connected to the other end of capacitor C7, the other end of resistor R3 is electrically connected to the DC terminal of driver U1, and the other end of resistor R4 is electrically connected to the CLK terminal of driver U1.

[0021] In this embodiment, the capacitance value range of capacitor C7 is from 10 nF to 100 μF, and the soft start time can be configured from 1 ms to 100 ms.

[0022] In this embodiment, the input voltage drives the transformer through the transformer drive circuit, where the SW1 channel and the SW2 channel work alternately in a complementary push-pull manner. When SW1 is turned on, SW2 is turned off. At this time, the voltage and current of the primary of the transformer are transferred to the secondary in the form of electromagnetic coupling. The ratio of the primary voltage to the secondary voltage is equal to the turns ratio of the transformer, and the ratio of the primary current to the secondary current is equal to the reciprocal of the turns ratio of the transformer. The electric energy transferred to the secondary of the transformer flows to the rear-end load (here is the active antenna) through the loop formed by diode D1. Similarly, when SW2 is turned on, SW1 is turned off. At this time, the voltage and current of the primary of the transformer are also transferred to the secondary in the form of electromagnetic coupling. The ratio of the primary voltage to the secondary voltage is still equal to the turns ratio of the transformer, and the ratio of the primary current to the secondary current is still equal to the reciprocal of the turns ratio of the transformer. At this time, the electric energy transferred to the secondary of the transformer flows to the rear-end load (here is the active antenna) through the loop formed by diode D2. Through the alternating conduction of SW1 and SW2, energy is continuously transferred to the secondary. By reasonably designing the turns ratio of the transformer and the duty cycle of the conduction of SW1 and SW2, the required secondary output voltage can be accurately obtained. From the above description, it can be seen that the electric energy is transferred from the primary to the secondary in the form of magnetic field coupling at this time, and the primary and secondary are electrically isolated. When the secondary encounters extreme situations such as lightning surges, it will not have too much impact on the primary, effectively improving the reliability of the entire system.

[0023] The output module, connected to the rectification circuit, includes a multi-stage parallel filter capacitor network for suppressing the output voltage ripple.

[0024] In this embodiment, it further includes: The soft start module, integrated in the transformer drive circuit, suppresses the inrush current during power-on by controlling the capacitor charging time, and the soft start time Satisfies: Wherein, C is the adjustable capacitance value, that is, capacitor C7; Is the driver threshold voltage; I is the constant charging current.

[0025] Specifically, as Figure 2 Shown, the negative electrodes of diode D1 and diode D2 are electrically connected. The multi-stage parallel filter capacitor network specifically includes capacitor C4, capacitor C5, and capacitor C6. Capacitor C4, capacitor C5, and capacitor C6 are connected in parallel with each other. One end of capacitor C6 outputs the supply voltage, one end of capacitor C6 is electrically connected to the negative electrode of diode D1, and the other end of capacitor C6 is grounded.

[0026] In this embodiment, as Figure 2As shown in the figure, where the dashed box 1 is the input voltage, 2 is the input filter network, which is used to reduce the ripple of the input power supply and increase the stability of the system power supply. 3 is the transformer drive circuit configuration network, whose main function is to configure the main functional parameters of the isolated power supply. 4 is the driver U1, which is the core component of the isolated power supply. It alternately drives the transformer through two channels, SW1 and SW2, to work in a pre-configured working mode, realizing the transfer of electrical energy from the primary side to the secondary side and obtaining the desired voltage on the secondary side. 5 is the transformer, which realizes the conversion of electrical energy from the primary side to the secondary side through the principle of electromagnetic induction. 6 is the diode network, which realizes the rectification function by using the unidirectional conduction characteristic. 7 is the output filter network, which is used to reduce the ripple of the output power supply and improve the stability of the output voltage. 8 is the finally obtained output voltage.

[0027] In this embodiment, as Figure 2 shown, when the primary circuit is powered on, the driver U1 enters the soft start process. At the moment when the power is applied, since the output voltage has not been established yet, a large inrush current will be generated in the primary circuit. This current will have a large impact on the primary circuit. The isolated power supply adopts the soft start technology to gradually increase the starting current to suppress the inrush current generated in the initial stage of power on. After entering the soft start process, the driver will charge the capacitor C7 with a constant current at this time. When the voltage of C7 reaches a certain threshold, the soft start process ends and enters the normal working mode. The duration of the soft start process is T start . After entering the normal working mode, the driver U1 will alternately conduct the SW1 and SW2 channels at the pre-set working frequency. The setting of the working frequency is controlled by the resistor R4. A low resistance value corresponds to a higher working frequency, and a high resistance value corresponds to a lower working frequency. The best working frequency can be selected according to the actual needs. Generally, a higher working frequency will reduce the size and cost of the filter, but it will bring higher losses and lower efficiency.

[0028] When SW1 is turned on, SW2 is turned off. The primary winding of transformer T1, pins 2-3, is connected to the voltage. The voltage polarity is that pin 2 is positive and pin 3 is negative. At this time, the current flows in from pin 2 and out from pin 3. According to the characteristics of the same-name terminals of the transformer and the principle of electromagnetic induction, an induced voltage will be generated between the secondary winding 6-5 and the secondary winding 5-4 of transformer T1. The polarity of the induced voltage is that the voltage at pin 6 is greater than the voltage at pin 5, and the voltage at pin 5 is greater than the voltage at pin 4. The magnitude of the induced voltage depends on the turns ratio of the transformer. The larger the turns ratio, the smaller the induced voltage. At this time, diode D1 is turned on and diode D2 is turned off. The current is transmitted to the load end through diode D1. Capacitors C4, C5, and C6 form an output filter network, which can reduce the ripple of the output voltage. After the conduction time Ton, SW1 is turned off. The magnitude of the conduction time Ton is jointly determined by the duty cycle D and the operating frequency F. Ton = D * F. The duty cycle D is a function of the input voltage Vin. At this time, the input voltage Vin is specifically 5V and the resistor R3. And it keeps changing dynamically. Generally, the duty cycle D and Vin are in an inverse relationship. When Vin increases, the duty cycle D decreases. The product of the two remains basically constant. This is beneficial to minimizing the line regulation of the entire isolated power supply. Generally, the duty cycle D corresponding to the rated Vin is set at 25% by setting the value of resistor R3. After SW1 is turned off, after the Toff time, Toff = (1 - D) * F.

[0029] When SW2 is turned on, SW1 is turned off. The primary winding of transformer T1, pins 2-1, is connected to the voltage. The voltage polarity is that pin 2 is positive and pin 1 is negative. At this time, the current flows in from pin 2 and out from pin 1. According to the characteristics of the same-name terminals of the transformer and the principle of electromagnetic induction, an induced voltage will be generated between the secondary winding 4-5 and the secondary winding 5-6 of transformer T1. The polarity of the induced voltage is that the voltage at pin 4 is greater than the voltage at pin 5, and the voltage at pin 5 is greater than the voltage at pin 6. At this time, diode D2 is turned on and diode D1 is turned off. The current is transmitted to the load end through diode D2. Through this periodic alternating conduction, electrical energy is continuously transferred from the primary to the secondary, achieving complete electrical isolation between the primary and secondary.

[0030] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. Isolated power supply circuit based on an RTK active antenna for industrial drones, characterized in that, Comprising: An input module, configured to receive the input voltage of the drone system and configure an input filter network to suppress the input power supply ripple; An isolation conversion module, connected to the input module, including a transformer drive circuit, an isolation transformer, and a rectification circuit. The transformer drive circuit is configured to alternately drive the primary winding of the isolation transformer in a complementary push-pull manner, and the operating frequency is dynamically configured through an external resistor, where the resistance value is inversely proportional to the frequency. The turns ratio of the primary and secondary windings of the isolation transformer is dynamically adjusted according to the input voltage and the required voltage of the active antenna, and complete electrical isolation is achieved between the primary and secondary. The rectification circuit is connected to the secondary winding of the isolation transformer and includes diode D1 and diode D2, forming a unidirectional current path during the alternating conduction period to convert the secondary alternating current into continuous direct current; An output module, connected to the rectification circuit, including a multi-stage parallel filter capacitor network for suppressing the output voltage ripple.

2. The isolated power supply circuit based on the RTK active antenna of an industrial drone according to claim 1, wherein The transformer drive circuit includes a first switch channel SW1 and a second switch channel SW2. The first switch channel SW1 and the second switch channel SW2 are alternately turned on in a complementary push-pull manner, and the duty cycle D is inversely regulated dynamically with respect to the input voltage , satisfying: where k is a proportionality constant configured through an external resistor network.

3. The isolated power supply circuit based on the industry drone RTK active antenna according to claim 1, wherein The input filter network specifically includes capacitor C1, capacitor C2, and capacitor C3. Capacitor C1, capacitor C2, and capacitor C3 are connected in parallel with each other. One end of capacitor C1 receives the input voltage of the drone system, and the other end of capacitor C1 is grounded.

4. The isolated power supply circuit based on the industry drone RTK active antenna according to claim 1, wherein The transformer drive circuit specifically includes driver U1, resistor R1, resistor R2, resistor R3, resistor R4, and capacitor C7. One end of resistor R1, one end of resistor R2, one end of resistor R3, one end of resistor R4, and one end of capacitor C7 are grounded together. The other end of resistor R1 is electrically connected to the SR terminal of driver U1. The other end of resistor R2 is electrically connected to the SS terminal of driver U1. The other end of resistor R2 is electrically connected to the other end of capacitor C7. The other end of resistor R3 is electrically connected to the DC terminal of driver U1. The other end of resistor R4 is electrically connected to the CLK terminal of driver U1.

5. The isolated power supply circuit based on the RTK active antenna of the industrial drone according to claim 4, characterized in that, Further comprising: The soft start module, integrated in the transformer drive circuit, suppresses the in-rush current during power-on by controlling the capacitor charging time, and the soft start time satisfies: where C is the adjustable capacitance value, i.e., capacitor C7; is the driver threshold voltage; I is the constant charging current.

6. The isolated power supply circuit based on the RTK active antenna of the industrial drone according to claim 1, characterized in that, The negative electrodes of diode D1 and diode D2 are electrically connected.

7. The isolated power supply circuit based on the RTK active antenna of an industrial drone according to claim 6, characterized in that, The multi-stage parallel filter capacitor network specifically includes capacitor C4, capacitor C5, and capacitor C6. Capacitor C4, capacitor C5, and capacitor C6 are connected in parallel with each other. One end of capacitor C6 outputs the supply voltage, one end of capacitor C6 is electrically connected to the negative electrode of diode D1, and the other end of capacitor C6 is grounded.

8. The isolated power supply circuit based on the industry UAV RTK active antenna according to claim 5, wherein, The capacitance value range of the capacitor C7 is from 10 nF to 100 μF, and the soft start time can be configured from 1 ms to 100 ms.

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