An inductance voltage integration-based short circuit protection device for an electric propulsion anode power supply

Abstract

The application relates to a short-circuit protection device of an electric propulsion anode power supply based on inductance voltage integration, which comprises an inductance voltage integration sampling circuit, an input end of the inductance voltage integration sampling circuit being connected with two ends of a boost inductance of a BOOST boost circuit or two ends of the boost inductance and two ends of a resonant inductance of an LLC resonant conversion circuit; the inductance voltage integration sampling circuit collects voltage signals of the two ends of the boost inductance or the two ends of the boost inductance and the two ends of the resonant inductance, and outputs a sampling voltage through integral operation; the sampling voltage and an inductance current are in a proportional relationship; and a main control chip is connected with the inductance voltage integration sampling circuit, is configured to receive the sampling voltage and compare the sampling voltage with a short-circuit threshold voltage, and stops outputting a driving PWM signal when the sampling voltage is greater than the short-circuit threshold voltage, so that the BOOST boost circuit and the LLC resonant conversion circuit are stopped. The short-circuit protection device of the application can realize no sampling loss, high operation efficiency, high integration, comprehensive protection range and fast response at the hardware level.

Description

Technical Field

[0001] This invention relates to the field of electric propulsion anode power supply technology, and in particular to a short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration. Background Technology

[0002] Electric thrusters are core power devices in aerospace and deep space exploration. Their anode power supplies must meet requirements such as high-voltage output, high-power operation, high operational stability, and strong short-circuit resistance. Currently, electric propulsion anode power supplies often adopt a BOOST-LLC cascaded topology. The front-stage BOOST boost circuit achieves wide input voltage range boost conversion, while the rear-stage LLC resonant converter provides electrical isolation, regulated output, and soft-switching operation. The entire topology has advantages such as high power density, high conversion efficiency, and low electromagnetic interference.

[0003] Short circuit faults are the most dangerous type of fault during the operation of electric propulsion anode power supplies. Problems such as output load short circuits, power device breakdown short circuits, and circuit line short circuits can all cause a sudden and sharp increase in circuit current, which can burn out power switching devices, resonant elements, and downstream electric propulsion loads. Therefore, short circuit protection is an indispensable core component in anode power supply design.

[0004] Currently, current sampling and short-circuit protection solutions for this type of power supply are mainly divided into two categories: The first type involves connecting a sampling resistor in series in the power circuit. This method has the following drawbacks: the sampling resistor introduces inherent power losses, reduces the overall power conversion efficiency, and can cause severe temperature rise under high current conditions.

[0005] The second type is to configure current transformers. However, current transformers are large in size and expensive, which is not conducive to the miniaturization and modular integration of power supplies. In addition, they are prone to magnetic saturation under high current operating conditions, which can lead to sampling failure.

[0006] In addition, traditional protection circuits typically use fuses to achieve overcurrent protection, resulting in slow circuit response speeds that are difficult to meet the stringent requirements of microsecond-level rapid fault cutoff in electric propulsion anode power supplies.

[0007] Therefore, there is an urgent need for a short-circuit protection device for the electric propulsion anode power supply with low sampling loss, high integration, and fast response speed. Summary of the Invention

[0008] To address at least some of the aforementioned problems in the prior art, the present invention provides a short-circuit protection device for an electric propulsion anode power supply based on inductor voltage integration, comprising: An inductor voltage integration sampling circuit has its input terminal connected to the two ends of the boost inductor of a BOOST boost circuit or the two ends of the boost inductor of a BOOST boost circuit and the two ends of the resonant inductor of an LLC resonant converter circuit. The inductor voltage integration sampling circuit acquires the voltage signal across the boost inductor or the two ends of the boost inductor and the resonant inductor, and outputs a sampled voltage through integration. The sampled voltage is directly proportional to the inductor current. The main control chip is connected to the inductor voltage integration sampling circuit and is configured to receive the sampled voltage and compare it with the short-circuit threshold voltage. When the sampled voltage is greater than the short-circuit threshold voltage, it stops outputting the drive PWM signal, thereby turning off the BOOST boost circuit and the LLC resonant converter circuit.

[0009] Furthermore, the BOOST boost circuit and the LLC resonant converter circuit are cascaded to form an electric propulsion anode power supply circuit.

[0010] Furthermore, the output of the inductor voltage integration sampling circuit is connected to the current limiting protection pin of the main control chip, and the current limiting protection pin has a built-in comparator.

[0011] Furthermore, the input terminals of the two inductor voltage integration sampling circuits are respectively connected to the two ends of the boost inductor of the BOOST boost circuit and the two ends of the resonant inductor of the LLC resonant converter circuit; The outputs of the two inductor voltage integration sampling circuits are connected to the current limiting protection pin of the main control chip.

[0012] Furthermore, the inductor voltage integration sampling circuit includes: A symmetrical differential integrator is configured to have a sampling circuit acquire voltage signals across a boost inductor or between a boost inductor and a resonant inductor, perform integration, and obtain a first-stage analog voltage; and The in-phase amplifier is configured to proportionally amplify the first-stage output voltage and output the sampled voltage to the current-limiting protection pin of the main control chip.

[0013] Furthermore, the input side of the BOOST boost circuit is connected to a DC power supply, and the output side is connected to a DC bus support capacitor; The BOOST boost circuit includes: The boost inductor has its first terminal connected to the positive terminal of the DC power supply and its second terminal connected to the freewheeling MOSFET Q1 and the switching transistor Q2. The first energy storage capacitor C1 has its first end connected to the positive terminal of the DC power supply and the first end of the boost inductor, and its second end connected to the negative terminal of the DC power supply and the switching transistor Q2. The second energy storage capacitor has its first end connected to the positive terminal of the DC power supply and the first end of the boost inductor, and its second end connected to the freewheeling MOSFET Q1.

[0014] Furthermore, the LLC resonant converter circuit is connected to both ends of the DC bus support capacitor; The LLC resonant converter circuit includes a primary-side full-bridge circuit, a resonant cavity, a transformer, and a rectifier-filter circuit connected in sequence, wherein: The primary-side full-bridge circuit includes a first power switch Q3, a second power switch Q4, a third power switch Q5, and a fourth power switch Q6; The first power switch Q3 and the third power switch Q5 are connected in series to form the first bridge arm; the second power switch Q4 and the fourth power switch Q6 are connected in series to form the second bridge arm; the positive terminal of the DC bus support capacitor is connected to the drain of the first power switch Q3 and the drain of the second power switch Q4; the negative terminal of the DC bus support capacitor is connected to the source of the third power switch Q5 and the source of the fourth power switch Q6. The resonant cavity includes a resonant capacitor and a resonant inductor. The first end of the resonant capacitor C4 is connected to the midpoint of the connection between the first power switch Q3 and the third power switch Q5. The second end of the resonant capacitor C4 is connected to the first end of the resonant inductor. The second end of the resonant inductor is connected to the first end of the transformer. The transformer includes a primary winding, a magnetic core, and a secondary winding. The first end of the primary winding is connected to a resonant inductor, and the second end of the primary winding is connected to the midpoint between the second power switch Q4 and the fourth power switch Q6. The secondary winding is connected to a rectifier and filter circuit. The rectifier and filter circuit includes a secondary rectifier circuit and an output filter capacitor; the AC input terminal of the secondary rectifier circuit is electrically connected to the secondary winding of the transformer; the output filter capacitor C5 is connected in parallel at the DC output terminal of the secondary rectifier circuit.

[0015] Furthermore, it also includes a driving circuit, whose input terminal receives the driving PWM signal from the main control chip, and whose output terminal is connected to the gates of freewheeling MOSFET Q1, switching transistor Q2, first power switching transistor Q3, second power switching transistor Q4, third power switching transistor Q5 and fourth power switching transistor Q6.

[0016] Furthermore, during the operation of the BOOST boost circuit and the LLC resonant converter circuit, the inductor voltage integration sampling circuit collects the voltage signal across the boost inductor or the voltage signal across the resonant inductor and the voltage signal across the boost inductor in real time, and converts the voltage signal into a sampling voltage that is proportional to the inductor current through integration. The sampled voltage is directly input to the current limiting protection pin of the main control chip to determine whether the sampled voltage exceeds the short-circuit threshold voltage. When the sampled voltage is lower than the short-circuit threshold voltage, the chip outputs the drive PWM signal normally. When the sampled voltage is greater than the short-circuit threshold voltage, the main control chip stops outputting the drive PWM signal.

[0017] Furthermore, the symmetrical differential integrator includes: a first input resistor R1, a second input resistor R2, a first integrating capacitor C11, a feedback capacitor C12, a first operational amplifier N1A, a first voltage divider resistor R3, and a second voltage divider resistor R4. One end of the first input resistor R1 is connected to the first terminal of the boost voltage, and the other end is connected to the non-inverting input terminal of the first operational amplifier N1A; One end of the second input resistor R2 is connected to the second terminal of the boost voltage, and the other end is connected to the inverting input terminal of the first operational amplifier N1A; The output of the first operational amplifier N1A is connected to a non-inverting amplifier; One end of the first voltage divider resistor R3 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A, and the other end is connected to the first terminal of the first integrating capacitor C11; the midpoint of the connection between the first voltage divider resistor R3 and the first integrating capacitor C11 is grounded. The second terminal of the first integrating capacitor C11 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A; One end of the second voltage divider resistor R4 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A; the first end of the feedback capacitor C12 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A. The midpoint of the connection between the second voltage divider resistor R4 and the feedback capacitor C12 is connected to the output terminal of the first operational amplifier N1A.

[0018] The present invention has at least the following beneficial effects: The short-circuit protection device of this invention has no sampling loss and high operating efficiency: it reuses the boost inductor built into the BOOST boost circuit as a signal acquisition element and uses voltage integration to indirectly detect current, eliminating the lossy components such as traditional sampling resistors and current transformers, completely eliminating power loss in the sampling stage, and is suitable for the application scenario of long-term high-power continuous operation of electric propulsion power supplies.

[0019] The short-circuit protection device of the present invention has an extremely simple circuit and a very high degree of integration: it completely eliminates external circuits such as external comparators and blocking logic, and directly relies on the protection function of the current limiting protection pin built into the main control chip to realize fault judgment and drive shutdown. The hardware structure is greatly simplified, the cost is lower and the reliability is higher.

[0020] This invention samples the inductor current of the boost inductor in the pre-stage BOOST boost circuit, and can simultaneously monitor short-circuit faults at the BOOST side, LLC resonant side, etc., solving the protection blind zone problem that exists in traditional methods that only sample the primary side current. The protection range is more comprehensive, and the overall protection safety is greatly improved.

[0021] The short-circuit protection device of the present invention can achieve hardware-level ultra-fast response: relying on the native protection mechanism of the main control chip hardware pins, without the need for software calculation and logic delay, the response speed reaches the microsecond level, and can complete the shutdown before the short-circuit current surge is formed, effectively protecting power devices and electric propulsion loads. Attached Figure Description

[0022] To further illustrate the above and other advantages and features of the various embodiments of the present invention, a more specific description of the embodiments of the invention will be presented with reference to the accompanying drawings. It is to be understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by identical or similar reference numerals for clarity.

[0023] Figure 1 A circuit diagram of an electric propulsion anode power supply according to the present invention is shown.

[0024] Figure 2 A schematic diagram of a short-circuit protection device for an electric propulsion anode power supply based on inductor voltage integration according to the present invention is shown.

[0025] Figure 3 A schematic diagram of another electric propulsion anode power supply short-circuit protection device based on inductor voltage integration according to the present invention is shown.

[0026] Figure 4 A schematic diagram of an inductor voltage integration sampling circuit according to the present invention is shown. Detailed Implementation

[0027] It should be noted that the components in the accompanying drawings may be shown exaggerated for illustrative purposes and may not be to scale.

[0028] In this invention, the various embodiments are merely intended to illustrate the solutions of the invention and should not be construed as limiting.

[0029] In this invention, unless otherwise specified, the quantifiers “a” and “one” do not exclude scenarios involving multiple elements.

[0030] It should also be noted that, in the embodiments of the present invention, only a portion of the parts or components may be shown for clarity and simplicity. However, those skilled in the art will understand that, under the teachings of the present invention, the required parts or components can be added as needed for specific scenarios.

[0031] It should also be noted that within the scope of this invention, the terms "same", "equal", and "equal to" do not mean that the two values ​​are absolutely equal, but allow for a certain reasonable error. In other words, the terms also cover "substantially the same", "substantially equal", and "substantially equal to".

[0032] It should also be noted that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not explicitly or implicitly suggest that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] Furthermore, the embodiments of the present invention describe the process steps in a specific order. However, this is only for the convenience of distinguishing each step, and is not a limitation on the order of each step. In different embodiments of the present invention, the order of each step can be adjusted according to the process.

[0034] Existing short-circuit protection schemes for electric propulsion anode power supplies have the following drawbacks: First, traditional current sampling schemes rely on active devices such as sampling resistors and current transformers, which have technical problems such as high sampling loss, low overall efficiency, poor equipment integration, and easy magnetic saturation failure under high current conditions. Second, it can only monitor primary current short-circuit faults, which creates a protection blind zone and makes it difficult to achieve full-area fault protection. Third, traditional short-circuit protection circuits require a large number of external components such as external comparators and logic blocking circuits, resulting in complex circuit architecture, high hardware cost, and low reliability. Fourth, relying heavily on software logic for judgment and having a long response delay, it cannot meet the microsecond-level ultra-fast short-circuit protection requirements of aerospace electric propulsion power supplies, which can easily lead to the burnout of power devices and damage to the load.

[0035] Figure 1 A circuit diagram of an electric propulsion anode power supply according to the present invention is shown.

[0036] like Figure 1 As shown, the electric propulsion anode power supply includes an electric propulsion anode power supply circuit, a main control chip 100, and a drive circuit 200.

[0037] like Figure 1 As shown, the electric propulsion anode power supply circuit includes a cascaded BOOST boost circuit 10 and an LLC resonant converter circuit.

[0038] The input side of the BOOST boost circuit 10 is connected to a DC power supply, and the output side is connected to a DC bus support capacitor C3.

[0039] The BOOST boost circuit 10 includes a boost inductor L1, a first energy storage capacitor C1, a second energy storage capacitor C2, a freewheeling MOSFET Q1, and a switching transistor Q2.

[0040] The first terminal of the boost inductor L1 is connected to the positive terminal of the DC power supply, and the second terminal is connected to the freewheeling MOSFET Q1 and the switching transistor Q2.

[0041] The switching transistor Q2 is a MOSFET, and the gates of the switching transistor Q2 and the freewheeling MOSFET Q1 are connected to the drive circuit 200.

[0042] The first terminal of the first energy storage capacitor C1 is connected to the positive terminal of the DC power supply and the first terminal of the boost inductor L1, and the second terminal is connected to the negative terminal of the DC power supply and the switching transistor Q2.

[0043] The first terminal of the second energy storage capacitor C2 is connected to the positive terminal of the DC power supply and the first terminal of the boost inductor L1, and the second terminal is connected to the freewheeling MOSFET Q1.

[0044] The BOOST boost circuit 10 can draw power from the first energy storage capacitor C1 nearby.

[0045] The LLC resonant converter circuit can draw power from the second energy storage capacitor C2 and the DC bus support capacitor C3 nearby.

[0046] The capacitor voltage cannot change abruptly. The first energy storage capacitor C1, the second energy storage capacitor C2, and the DC bus support capacitor C3 can maintain voltage stability.

[0047] The LLC resonant converter circuit is connected to both ends of the DC bus support capacitor C3.

[0048] The LLC resonant converter circuit includes, in sequence: a primary-side full-bridge circuit 20, a resonant cavity 30, a transformer 40, and a rectifier and filter circuit 50.

[0049] The primary-side full-bridge circuit 20 includes a first power switch Q3, a second power switch Q4, a third power switch Q5, and a fourth power switch Q6.

[0050] The first power switch Q3 and the third power switch Q5 are connected in series to form the first bridge arm; the second power switch Q4 and the fourth power switch Q6 are connected in series to form the second bridge arm; the two bridge arms are connected in parallel, and their input terminals are connected to both ends of the DC bus support capacitor C3.

[0051] The positive terminal of the DC bus support capacitor is connected to the drain of the first power switch Q3 and the drain of the second power switch Q4; the negative terminal of the DC bus support capacitor is connected to the source of the third power switch Q5 and the source of the fourth power switch Q6.

[0052] The resonant cavity 30 is connected at the midpoint of the connection between the first power switch Q3 and the third power switch Q5.

[0053] The first power switch Q3 and the fourth power switch Q6 are simultaneously turned on and off. The second power switch Q4 and the third power switch Q5 are simultaneously turned on and off. The first power switch Q3 and the third power switch Q5 are not simultaneously turned on, and the second power switch Q4 and the fourth power switch Q6 are simultaneously turned on.

[0054] The gates of the first power switch Q3, the second power switch Q4, the third power switch Q5, and the fourth power switch Q6 are connected to the drive circuit 200.

[0055] The resonant cavity 30 includes a resonant capacitor C4 and a resonant inductor L2.

[0056] The first terminal of the resonant capacitor C4 is connected to the midpoint between the first power switch Q3 and the third power switch Q5. The second terminal of the resonant capacitor C4 is connected to the first terminal of the resonant inductor L2. The second terminal of the resonant inductor L2 is connected to the first terminal of the transformer 40.

[0057] Transformer 40 includes a primary winding, a magnetic core, and a secondary winding. The first end of the primary winding is connected to the midpoint of the connection between the resonant inductor L2, the second power switch Q4, and the fourth power switch Q6.

[0058] The secondary winding is connected to the rectifier filter circuit 50.

[0059] The rectifier-filter circuit 50 includes a secondary rectifier circuit and an output filter capacitor C5. The AC input terminal of the secondary rectifier circuit is electrically connected to the secondary winding of the transformer 40; the output filter capacitor C5 is connected in parallel to the DC output terminal of the secondary rectifier circuit.

[0060] The rectifier and filter circuit 50 is used to convert high-frequency AC voltage into a stable DC voltage to provide power to the electric propulsion anode. The secondary rectifier circuit converts alternating high-frequency AC power into pulsating DC power, filters out AC voltage ripple, and obtains a stable DC high voltage to power the electric propulsion anode.

[0061] The secondary rectifier circuit includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, and a fourth rectifier diode D4. The first rectifier diode D1 and the third rectifier diode D3 are connected together, and the second rectifier diode D2 and the fourth rectifier diode D4 are connected together.

[0062] The midpoint between the first rectifier diode D1 and the third rectifier diode D3, and the midpoint between the second rectifier diode D2 and the fourth rectifier diode D4, are respectively connected to the two ends of the secondary winding.

[0063] The first terminal of the output filter capacitor C5 is connected to the positive terminals of the second rectifier diode D2 and the third rectifier diode D3, and the second terminal of the output filter capacitor C5 is connected to the negative terminals of the first rectifier diode D1 and the fourth rectifier diode D4.

[0064] The electric propulsion anode power supply circuit ultimately outputs high-voltage direct current to power the anode of the electric propulsion unit.

[0065] The main control chip 100 is connected to the drive circuit 200. The drive circuit 200 is connected to the gates of the freewheeling MOSFET Q1, the switching transistor Q2, and the power switching transistors Q3 to Q6 in the electric propulsion anode power supply circuit.

[0066] The main control chip 100 sends a drive PWM signal to the drive circuit 200, and the drive circuit 200 controls the freewheeling MOSFET Q1, the switching transistor Q2, and the power switching transistors Q3 to Q6 to turn on and off based on the drive PWM signal.

[0067] Figure 2 A schematic diagram of a short-circuit protection device for an electric propulsion anode power supply based on inductor voltage integration according to the present invention is shown.

[0068] like Figure 2 As shown, the input terminal of the inductor voltage integration sampling circuit 300 is connected in parallel across the boost inductor L1 of the BOOST boost circuit. It is used to collect the voltage signal across the boost inductor L1 in real time, and finally output the sampled voltage signal through integration and amplification.

[0069] The output of the inductor voltage integration sampling circuit 300 is connected to the current limiting protection pin of the main control chip 100 (pin 9 of the UC1825A chip), and the current limiting protection pin has a built-in comparator.

[0070] The electric propulsion anode power supply circuit is powered on and running normally. The BOOST boost circuit and LLC resonant converter circuit work synchronously, and a periodic alternating voltage is generated across the boost inductor L1.

[0071] The inductor voltage integration sampling circuit 300 collects the voltage across the boost inductor L1 in real time and converts the voltage signal into a sampling voltage that is directly proportional to the inductor current through integration.

[0072] The sampled voltage is directly input to the current-limiting protection pin of the main control chip 100, and the comparator built into the current-limiting protection pin performs automatic fault detection. The comparator compares the sampled voltage with the set short-circuit threshold voltage. When the sampled voltage is lower than the short-circuit threshold voltage, the chip outputs the drive PWM signal normally. When the sampled voltage is higher than the short-circuit threshold voltage, the main control chip 100 stops outputting the drive PWM signal. All MOSFETs in the BOOST boost circuit and LLC resonant converter circuit are turned off, completing the short-circuit protection.

[0073] This invention eliminates the traditional external comparator and external logic blocking circuit, directly using the main control chip's No. 9 current-limiting protection pin as the sole fault detection and drive blocking port. The voltage signal output from the integral sampling circuit is directly connected to the current-limiting protection pin. Fault detection and drive shutdown are achieved based on the chip's built-in overvoltage threshold judgment and hardware lockout mechanism, eliminating the need for additional fault detection and logic blocking circuits and significantly simplifying the hardware architecture. When the sampled voltage signal input to the current-limiting protection pin exceeds the chip's built-in short-circuit threshold voltage, the main control chip 100 immediately locks out the internal PWM output, instantly shutting down all switching transistor drive signals in the BOOST boost circuit and LLC resonant converter circuit, achieving zero-delay, full-domain short-circuit protection.

[0074] Figure 3 A schematic diagram of another electric propulsion anode power supply short-circuit protection device based on inductor voltage integration according to the present invention is shown.

[0075] Figure 3 The protective device shown is Figure 2 The difference in the protection device shown is that two inductor voltage integration sampling circuits 300 are set up. The input terminal of one inductor voltage integration sampling circuit 300 is connected in parallel across the boost inductor L1 of the BOOST boost circuit, and the input terminal of the other inductor voltage integration sampling circuit 300 is connected in parallel across the resonant inductor L2 of the LLC resonant converter circuit.

[0076] The outputs of the two inductor voltage integration sampling circuits 300 can be connected to the current limiting protection pin of the main control chip 100 through parallel connection of diodes or gates, or by direct superposition and adaptation.

[0077] Two inductor voltage integration sampling circuits are set up to simultaneously monitor the abnormal current of the front-end BOOST boost circuit and the abnormal current of the rear-end LLC resonant converter circuit, thereby improving the range and reliability of short-circuit protection.

[0078] Whether an overcurrent short circuit occurs on the BOOST boost circuit side or an abnormal short circuit occurs in the LLC resonant cavity, an abnormal increase in the voltage of either inductor can trigger fault protection after integral sampling. The chip immediately stops the PWM output, and both stages of the topology shut down synchronously, further improving the reliability of the protection. It achieves dual-source monitoring and unified protection on a single pin, greatly expanding the fault detection range without adding control and judgment circuits.

[0079] This invention allows for flexible selection of single-channel or dual-channel sampling architectures based on protection level requirements, resulting in greater topology adaptability and engineering versatility.

[0080] The core principle of short-circuit protection in this invention is as follows: When a short-circuit fault occurs in the system, the operating current of the BOOST boost inductor or LLC resonant inductor increases sharply. The sampling voltage output by the inductor voltage integral sampling circuit is positively correlated with the inductor fault current. The short-circuit threshold voltage of the current limiting protection pin 9 of the main control chip is 1.2V. When the input voltage of this pin exceeds 1.2V, the chip immediately shuts off the PWM output to achieve fault protection. This invention adopts a dual-sampling architecture of front-stage BOOST inductor voltage integral detection and rear-stage LLC resonant inductor voltage integral detection. The two detection signals are synchronously connected to the main control chip in parallel through diodes. Regardless of whether a short-circuit fault occurs in the front-stage boost circuit or the rear-stage resonant circuit, causing an abnormal increase in inductor current, the corresponding integral sampling voltage will rise rapidly and exceed the set short-circuit threshold voltage, reliably triggering the hardware protection mechanism and achieving rapid blocking protection for short-circuit faults with full coverage of the two-stage topology.

[0081] Figure 4 A schematic diagram of an inductor voltage integration sampling circuit according to the present invention is shown.

[0082] The inductor voltage integration sampling circuit is a modified design based on the inductor voltage integration detection principle. Its input is directly connected in parallel across the BOOST boost inductor, replacing the traditional LLC resonant inductor sampling scheme. The circuit employs a dual-power supply mode and is equipped with two high-speed operational amplifiers (LM258).

[0083] like Figure 4 As shown, the inductor voltage integration sampling circuit includes a cascaded symmetrical differential integrator 310 and a non-inverting amplifier 320.

[0084] The non-inverting input of the symmetrical differential integrator 310 is connected to the first terminal of the boost inductor L1, and the inverting input is connected to the second terminal of the boost inductor L1.

[0085] The symmetrical differential integrator 310 integrates the voltage signal across the boost inductor L1 to obtain a first-stage analog voltage. The first-stage output voltage is directly proportional to the current of the boost inductor L1.

[0086] The output voltage of the first stage is proportionally amplified by a non-inverting amplifier 320 (a two-stage operational amplifier), and the sampled voltage is sent to the current limiting protection pin. The signal amplification factor of the non-inverting amplifier 320 can be flexibly adjusted according to the actual prototype parameters, resonant operating conditions, and protection threshold requirements to accurately match the effective recognition voltage range of the subsequent main control chip.

[0087] Since the sampling voltage and the current of the boost inductor L1 are directly proportional, the size of the boost inductor L1 can be determined based on the magnitude of the sampling voltage. When the sampling voltage exceeds the short-circuit threshold voltage, it indicates that the inductor current is too large, requiring the hardware protection mechanism to be triggered, and the chip immediately shuts off the PWM output.

[0088] The symmetrical differential integrator 310 includes a first input resistor R1, a second input resistor R2, a first integrating capacitor C11, a feedback capacitor C12, a first operational amplifier N1A, a first voltage divider resistor R3, and a second voltage divider resistor R4.

[0089] One end of the first input resistor R1 is connected to the first terminal of the boost inductor L1, and the other end is connected to the non-inverting input terminal of the first operational amplifier N1A.

[0090] One end of the second input resistor R2 is connected to the second end of the boost inductor L1, and the other end is connected to the inverting input of the first operational amplifier N1A.

[0091] The two power supply pins of the first operational amplifier N1A are connected to two DC power supplies, respectively. The output of the first operational amplifier N1A is connected to the non-inverting amplifier 320.

[0092] One end of the first voltage divider resistor R3 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A, and the other end is connected to the first terminal of the first integrating capacitor C11. The midpoint of the connection between the first voltage divider resistor R3 and the first integrating capacitor C11 is grounded.

[0093] The second terminal of the first integrating capacitor C11 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A.

[0094] One end of the second voltage divider resistor R4 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A. One end of the feedback capacitor C12 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A.

[0095] The midpoint of the connection between the second voltage divider resistor R4 and the feedback capacitor C12 is connected to the output terminal of the first operational amplifier N1A.

[0096] The non-inverting amplifier 320 includes a filter circuit and an amplification circuit. The amplification circuit includes a second operational amplifier N1B, a resistor to ground R6, and a feedback resistor R7.

[0097] The output of the first operational amplifier N1A is connected to the non-inverting input of the second operational amplifier N1B.

[0098] The two ends of the filter circuit are connected to the connection between the first operational amplifier N1A and the second operational amplifier N1B. The filter circuit includes a filter resistor R5 and a filter capacitor C13. The first end of the filter resistor R5 is connected to the connection between the first operational amplifier N1A and the second operational amplifier N1B, and the second end is connected to the first end of the filter capacitor C13. The second end of the filter capacitor C13 is connected to the connection between the first operational amplifier N1A and the second operational amplifier N1B.

[0099] One end of the resistor R6 is grounded, and the other end is connected to the inverting input of the second operational amplifier N1B. One end of the feedback resistor R7 is connected to the inverting input of the second operational amplifier N1B, and the other end is connected to the output of the second operational amplifier N1B.

[0100] The following describes the principle of an inductor voltage integration sampling circuit for detecting short circuits.

[0101] The formula for calculating the voltage at the non-inverting input of the symmetrical differential integrator 310 is as follows: (1), Where V1 is the potential at the first terminal of the boost inductor L1.

[0102] Current relationship at the inverting input terminal: The current flowing through the second input resistor R2 is equal to the current flowing through the feedback capacitor C12, therefore: (2), in Indicates the potential at the inverting input terminal. This represents the potential at the second terminal of the boost inductor L1. This represents the first-level analog voltage, and C represents the capacitance value of the feedback capacitor C12.

[0103] From the virtual shortest equation: V+ = V-, substituting into formula 2 and simplifying, we get: (3), This represents the capacitance value of the first integrating capacitor C11. This indicates the resistance value of the first input resistor R1. This represents the voltage across the boost inductor L1.

[0104] R3 and R4 are voltage divider resistors used to limit the maximum voltage of V+ and V-.

[0105] voltage across boost inductor L1 The calculation formula is as follows: (4), in Indicates inductor current. Indicates the instantaneous current of the inductor. This represents the rate of change of current over time. t represents the inductance, and t represents time.

[0106] The inductor current can be obtained based on Equation 4. Relationship with voltage: (5).

[0107] Substituting formula 5 into formula 3, we get: (6), Level 1 analog voltage With inductor current They are in a direct proportional relationship.

[0108] Level 1 analog voltage The signal is amplified proportionally by a non-inverting amplifier 320 (a two-stage operational amplifier). , This represents the final output sampled voltage. and These are the resistance values ​​of R6 to ground and R7 for feedback, respectively.

[0109] The symmetrical differential integrator 310 (a single-stage operational amplifier) ​​integrates the voltage signal across the boost inductor L1. Based on the inductor's electrical characteristics, the integral of the voltage across the inductor over time is linearly related to the inductor current. The circuit outputs a single-stage analog voltage after passing through the operational amplifier. It maintains a fixed proportional relationship with the BOOST inductor current.

[0110] The first-stage analog voltage is integrated by a non-inverting amplifier 320 (a two-stage operational amplifier). The signal amplification factor can be flexibly adjusted according to the actual prototype parameters, resonant operating conditions, and protection threshold requirements to accurately match the effective identification voltage range of the subsequent control chip.

[0111] This invention eliminates traditional lossy sampling devices such as sampling resistors and current transformers. Utilizing the volt-ampere characteristics of a boost inductor, it processes the alternating voltage of the inductor through operational amplifier integration, indirectly reconstructing the loop current in real time, thus achieving lossless, high-precision current sampling. This solves the technical problems of low sampling accuracy, high sampling loss, and susceptibility to magnetic saturation failure under high-frequency operating conditions in traditional sampling methods, significantly improving the overall operating efficiency and sampling stability of the power supply.

[0112] This invention eliminates the need for numerous external circuits such as external comparators, reference sources, and logic blocking required by traditional protection schemes. It directly connects the conditioned sampled signal to the hardware protection pin of the main control chip, relying on the chip's native hardware latching mechanism to achieve fault detection and instantaneous PWM shutdown. This completely eliminates the computational delay caused by software algorithm discrimination, achieving microsecond-level short-circuit fault response and significantly improving protection reliability and response speed.

[0113] This invention achieves full-domain fault coverage of a two-stage topology based on sampling of the front-stage BOOST boost inductor and LLC resonant inductor, making up for the deficiency of monitoring blind spots in single-channel sampling. It can be flexibly upgraded with multi-dimensional fault monitoring and adaptive protection functions, adapting to different power levels of aerospace electric propulsion power supply conditions. Its architecture compatibility and scalability are significantly better than traditional fixed protection schemes.

[0114] While some embodiments of the present invention have been described in this application, those skilled in the art will understand that these embodiments are merely illustrative. Numerous variations, alternatives, and improvements will arise in those skilled in the art under the teachings of this invention without departing from its scope. The appended claims are intended to define the scope of the invention and thereby cover methods and structures within the scope of the claims themselves and their equivalents.

Claims

1. A short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration, characterized in that, include: An inductor voltage integration sampling circuit has its input terminals connected to the two ends of the boost inductor of a BOOST boost circuit or the two ends of the boost inductor of a BOOST boost circuit and the two ends of the resonant inductor of an LLC resonant converter circuit. The inductor voltage integration sampling circuit acquires the voltage signal across the two ends of the boost inductor or the two ends of the boost inductor and the two ends of the resonant inductor, and outputs the sampled voltage through integration. The sampled voltage is directly proportional to the inductor current. as well as The main control chip is connected to the inductor voltage integration sampling circuit and is configured to receive the sampled voltage and compare it with the short-circuit threshold voltage. When the sampled voltage is greater than the short-circuit threshold voltage, it stops outputting the drive PWM signal, thereby turning off the BOOST boost circuit and the LLC resonant converter circuit.

2. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, The BOOST boost circuit and the LLC resonant converter circuit are cascaded to form an electric propulsion anode power supply circuit.

3. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, The output of the inductor voltage integration sampling circuit is connected to the current limiting protection pin of the main control chip, and the current limiting protection pin has a built-in comparator.

4. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, The input terminals of the two inductor voltage integration sampling circuits are respectively connected to the two ends of the boost inductor of the BOOST boost circuit and the two ends of the resonant inductor of the LLC resonant converter circuit; The outputs of the two inductor voltage integration sampling circuits are connected to the current limiting protection pin of the main control chip.

5. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, The inductor voltage integration sampling circuit includes: A symmetrical differential integrator is configured to have a sampling circuit acquire voltage signals across a boost inductor or between a boost inductor and a resonant inductor, perform integration, and obtain a first-stage analog voltage; and The in-phase amplifier is configured to proportionally amplify the first-stage output voltage and output the sampled voltage to the current-limiting protection pin of the main control chip.

6. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, The input side of the BOOST boost circuit is connected to a DC power supply, and the output side is connected to a DC bus support capacitor. The BOOST boost circuit includes: The boost inductor has its first terminal connected to the positive terminal of the DC power supply and its second terminal connected to the freewheeling MOSFET Q1 and the switching transistor Q2. The first energy storage capacitor C1 has its first end connected to the positive terminal of the DC power supply and the first end of the boost inductor, and its second end connected to the negative terminal of the DC power supply and the switching transistor Q2. The second energy storage capacitor has its first end connected to the positive terminal of the DC power supply and the first end of the boost inductor, and its second end connected to the freewheeling MOSFET Q1.

7. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 6, characterized in that, The LLC resonant converter circuit is connected to both ends of the DC bus support capacitor; The LLC resonant converter circuit includes a primary-side full-bridge circuit, a resonant cavity, a transformer, and a rectifier-filter circuit connected in sequence, wherein: The primary-side full-bridge circuit includes a first power switch Q3, a second power switch Q4, a third power switch Q5, and a fourth power switch Q6; The first power switch Q3 and the third power switch Q5 are connected in series to form the first bridge arm; the second power switch Q4 and the fourth power switch Q6 are connected in series to form the second bridge arm; the positive terminal of the DC bus support capacitor is connected to the drain of the first power switch Q3 and the drain of the second power switch Q4; the negative terminal of the DC bus support capacitor is connected to the source of the third power switch Q5 and the source of the fourth power switch Q6. The resonant cavity includes a resonant capacitor and a resonant inductor. The first end of the resonant capacitor C4 is connected to the midpoint of the connection between the first power switch Q3 and the third power switch Q5. The second end of the resonant capacitor C4 is connected to the first end of the resonant inductor. The second end of the resonant inductor is connected to the first end of the transformer. The transformer includes a primary winding, a magnetic core, and a secondary winding. The first end of the primary winding is connected to a resonant inductor, and the second end of the primary winding is connected to the midpoint between the second power switch Q4 and the fourth power switch Q6. The secondary winding is connected to a rectifier and filter circuit. The rectifier and filter circuit includes a secondary rectifier circuit and an output filter capacitor; the AC input terminal of the secondary rectifier circuit is electrically connected to the secondary winding of the transformer; the output filter capacitor C5 is connected in parallel at the DC output terminal of the secondary rectifier circuit.

8. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 7, characterized in that, It also includes a drive circuit, whose input terminal receives the drive PWM signal from the main control chip, and whose output terminal is connected to the gates of freewheeling MOSFET Q1, switching transistor Q2, first power switching transistor Q3, second power switching transistor Q4, third power switching transistor Q5, and fourth power switching transistor Q6.

9. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 1, characterized in that, During the operation of the BOOST boost circuit and LLC resonant converter circuit, the inductor voltage integration sampling circuit collects the voltage signal across the boost inductor or the voltage signal across the resonant inductor and the voltage signal across the boost inductor in real time, and converts the voltage signal into a sampling voltage that is proportional to the inductor current through integration. The sampled voltage is directly input to the current limiting protection pin of the main control chip to determine whether the sampled voltage exceeds the short-circuit threshold voltage. When the sampled voltage is lower than the short-circuit threshold voltage, the chip outputs the drive PWM signal normally. When the sampled voltage is greater than the short-circuit threshold voltage, the main control chip stops outputting the drive PWM signal.

10. The short-circuit protection device for electric propulsion anode power supply based on inductor voltage integration according to claim 5, characterized in that, The symmetrical differential integrator includes: a first input resistor R1, a second input resistor R2, a first integrating capacitor C11, a feedback capacitor C12, a first operational amplifier N1A, a first voltage divider resistor R3, and a second voltage divider resistor R4. One end of the first input resistor R1 is connected to the first terminal of the boost voltage, and the other end is connected to the non-inverting input terminal of the first operational amplifier N1A; One end of the second input resistor R2 is connected to the second terminal of the boost voltage, and the other end is connected to the inverting input terminal of the first operational amplifier N1A; The output of the first operational amplifier N1A is connected to a non-inverting amplifier; One end of the first voltage divider resistor R3 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A, and the other end is connected to the first terminal of the first integrating capacitor C11; the midpoint of the connection between the first voltage divider resistor R3 and the first integrating capacitor C11 is grounded. The second terminal of the first integrating capacitor C11 is connected to the line connecting the first input resistor R1 and the first operational amplifier N1A; One end of the second voltage divider resistor R4 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A; the first end of the feedback capacitor C12 is connected to the line connecting the second input resistor R2 and the first operational amplifier N1A, and the other end is connected to the output terminal of the first operational amplifier N1A. The midpoint of the connection between the second voltage divider resistor R4 and the feedback capacitor C12 is connected to the output terminal of the first operational amplifier N1A.

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