Aerospace craft efficient power conversion device based on three-level technology

Abstract

The invention relates to the technical field of power conversion, in particular to an efficient power conversion device for an aerospace craft based on a three-level technology. The circuit comprises an input filtering module, a voltage conversion module and a driving control module. According to the invention, the input filtering module is used for filtering the input voltage to maintain the stability of the input voltage, the voltage conversion module is used for converting the input DC voltage into the required output DC voltage, and the soft switching auxiliary regulation and control circuit is used for ensuring that the switching tube is switched under the conditions of zero voltage and zero current. The driving control module adopts a voltage and current double-closed-loop control strategy, generates a PWM pulse signal and controls on and off of a switching tube in the three-level voltage conversion circuit, so that switching loss is greatly reduced, power conversion efficiency is improved, overvoltage protection, overcurrent protection and overheating protection are adopted, the states of current and voltage are detected, and when an abnormal condition is detected, the three-level voltage conversion circuit is switched on and off. And the control circuit can quickly take corresponding protection measures.

Description

Technical Field

[0001] The present invention relates to the technical field of power conversion, and in particular to a high-efficiency power conversion device for aerospace vehicles based on three-level technology. Background Art

[0002] During missions, spacecraft require a stable and efficient power supply to support the normal operation of various electronic equipment and systems. The power conversion device is a key component of the spacecraft power system, and its performance directly affects the operating reliability and mission completion capability of the entire spacecraft. As an advanced power electronics technology, three-level technology has the advantages of low switching tube voltage stress, small output voltage harmonics, and high efficiency, and has been widely used in the industrial field.

[0003] At present, aerospace vehicles have very high requirements for power conversion devices. On the one hand, the volume of the power conversion device needs to be limited, and on the other hand, the power conversion device needs to have high conversion efficiency. Traditional power conversion devices have certain limitations in efficiency, volume and weight, and it is difficult to meet the growing high-performance requirements of modern aerospace vehicles. In order to use three-level technology to convert the input DC voltage into the required output DC voltage, improve the power conversion efficiency, use soft switching technology to assist in controlling the opening and closing of the switch tube, reduce switching losses, and ensure that the device meets the high standards of aerospace vehicles. Therefore, we propose a high-efficiency power conversion device for aerospace vehicles based on three-level technology. Summary of the Invention

[0004] The purpose of the present invention is to solve the limitations of traditional power conversion devices in terms of efficiency, volume and weight, which make it difficult to meet the growing high-performance requirements of modern aerospace vehicles. In order to use three-level technology to convert the input DC voltage into the required output DC voltage and improve the power conversion efficiency, soft switching technology is used to assist in controlling the opening and closing of the switch tube, reduce switching losses, and ensure that the device meets the high standards of aerospace vehicles.

[0005] To achieve the above objectives, the present invention provides a high-efficiency power conversion device for aerospace vehicles based on three-level technology, comprising an input filter module, a voltage conversion module, and a drive control module;

[0006] The input filter module filters the input voltage through the input filter circuit, uses the virtual short and virtual open functions of the operational amplifier A to eliminate high-frequency noise and clutter in the input voltage, and transmits the processed voltage to the voltage conversion module;

[0007] The voltage conversion module converts the input DC voltage into the required output DC voltage through a three-level voltage conversion circuit, adopts a space vector pulse width modulation strategy to optimize the switching sequence and switching timing of the switch tube to reduce switching losses, uses a soft switching auxiliary control circuit to enable the switch tube to switch under zero voltage and zero current conditions, and adopts active clamping soft switching technology to add auxiliary switch tubes and clamping capacitor elements in the main circuit to assist in controlling the switch tube of the three-level voltage conversion circuit;

[0008] The drive control module uses a digital signal processor as the core control unit, adopts a voltage and current dual closed-loop control strategy, generates a PWM pulse signal, controls the on and off of the switch tube in the three-level voltage conversion circuit, adopts overvoltage protection, overcurrent protection and overheating protection, and detects the current and voltage status.

[0009] As a further improvement of the present technical solution, the input filter module includes an input filter circuit, wherein the input filter circuit includes an operational amplifier A;

[0010] Pin 2 of the operational amplifier A is connected to one end of the resistor R1, and is connected in parallel to one end of the resistor R3 and one end of the capacitor C1. The other end of the resistor R1 is connected to the input voltage UI. Pin 3 of the operational amplifier A is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded. Pin 1 of the operational amplifier A is connected to the other end of the resistor R3 and the other end of the capacitor C1, and is connected in parallel to the output voltage UO.

[0011] As a further improvement of the technical solution, the voltage conversion module includes a DC conversion unit and a soft switching auxiliary unit;

[0012] The DC conversion unit switches the output voltage between positive level, zero level and negative level through different switch combinations in the three-level voltage conversion circuit, and uses three-level output to reduce switching loss;

[0013] The soft switching auxiliary unit utilizes a soft switching auxiliary control circuit to enable the switch tube to switch under the conditions of zero voltage and zero current, thereby assisting in regulating the switch tube of the three-level voltage conversion circuit.

[0014] As a further improvement of the present technical solution, the DC conversion unit includes a three-level voltage conversion circuit, wherein the three-level voltage conversion circuit includes a switch tube S1, a switch tube S2, a switch tube S3, a switch tube S4 and an inductor L1;

[0015] The gate of the switch tube S1 is connected to the anode of the diode D2 and the anode of the diode D3, the cathode of the diode D2 and the cathode of the diode D3 are connected to the input voltage UI, the drain of the switch tube S1 is connected to the gate of the switch tube S2 and the cathode of the diode D6, the drain of the switch tube S2 is connected to the cathode of the diode D1 and the cathode of the diode D4, and the gate of the switch tube S3, the drain of the switch tube S3 is connected to the cathode of the diode D5 and the gate of the switch tube S4, the drain of the switch tube S4 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to the anode of the diode D5 and the anode of the diode D6, and the capacitor C3;

[0016] The drain of the switch tube S2 is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to one end of the capacitor C5 and connected to the output voltage UO, and the other end of the capacitor C5 is connected to the anode of the diode D5 and the anode of the diode D6.

[0017] As a further improvement of the present technical solution, when the DC conversion unit adopts the space vector pulse width modulation strategy to optimize the switching sequence of the switching tube, redundant vectors are introduced to synthesize a new vector combination, and the most appropriate basic voltage vector combination is dynamically selected according to the real-time changes of the load.

[0018] As a further improvement of the present technical solution, when optimizing the switching sequence of the switching tube, the DC conversion unit designs a symmetrical switching sequence to make the on and off time distribution of the switching tube more uniform and reduce the switching state jump between two adjacent sampling cycles.

[0019] As a further improvement of the present technical solution, the soft switching auxiliary unit includes a soft switching auxiliary control circuit, wherein the soft switching auxiliary control circuit includes an inductor L2, a switch tube S5 and a diode D7;

[0020] The gate of the switch tube S5 is connected to the input voltage UI, the drain of the switch tube S5 is connected to one end of the inductor L2 and the anode of the diode D7, the cathode of the diode D7 is connected to one end of the capacitor C6 and one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C6 and the output voltage UO.

[0021] As a further improvement of the present technical solution, the soft switching auxiliary unit uses the inductor L2 and the capacitor C6 to form a resonant network, so that the voltage across the main switch tube S5 changes according to a sinusoidal law, so that the voltage across the main switch tube S5 is exactly zero when it is turned on next time.

[0022] As a further improvement of the present technical solution, the drive control module includes a feedback control unit and an abnormality protection unit;

[0023] The feedback control unit adopts a voltage and current dual closed-loop control strategy to generate a PWM pulse signal to control the on and off of the switch tube in the three-level voltage conversion circuit;

[0024] The abnormal protection unit adopts overvoltage protection, overcurrent protection and overheat protection, detects the status of current and voltage, monitors abnormal status, and issues early warning indications.

[0025] As a further improvement of the present technical solution, when the feedback control unit adopts a voltage-current dual closed-loop control strategy, a nested control structure is adopted, including a voltage outer loop and a current inner loop, and a voltage regulator is used to adjust the error signal.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This high-efficiency power conversion device for spacecraft, based on three-level technology, filters the input voltage through an input filter module to eliminate high-frequency noise and clutter in the input voltage, maintaining input voltage stability. A voltage conversion module converts the input DC voltage into the required output DC voltage. It employs a space vector pulse width modulation strategy to optimize the switching sequence and timing of the switches, reducing switching losses. A soft-switching auxiliary control circuit ensures that the switches switch under zero voltage and zero current conditions, achieving zero voltage turn-on and zero current turn-off. This avoids voltage and current overlap, significantly reduces switching losses, and improves power conversion efficiency.

[0028] 2. The drive control module adopts a voltage-current dual closed-loop control strategy to generate PWM pulse signals to control the on and off of the switch tube in the three-level voltage conversion circuit. The voltage loop is used as the outer loop to stabilize the output voltage, and the current loop is used as the inner loop to quickly track changes in load current and improve the dynamic response performance of the system. Overvoltage protection, overcurrent protection and overheating protection are adopted to detect the status of current and voltage. When an abnormal situation is detected, the control circuit can quickly take corresponding protective measures, turn off the switch tube, and issue an alarm signal to prevent damage to the power conversion device and other equipment of the aerospace vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0030] Figure 2 It is a schematic diagram of the overall details of the present invention;

[0031] Figure 3 is the input filter circuit diagram of the present invention;

[0032] Figure 4 is a three-level voltage conversion circuit diagram of the present invention;

[0033] Figure 5 This is a circuit diagram of the soft switch auxiliary control circuit of the present invention;

[0034] Figure 6 It is a schematic diagram of the physical object of the present invention;

[0035] Figure 7 This is a three-level PFM mode waveform diagram of the present invention;

[0036] Figure 8 This is a three-level PWM mode waveform diagram of the present invention.

[0037] The meaning of each number in the figure is:

[0038] 100, input filter module; 200, voltage conversion module; 210, DC conversion unit; 220, soft switch auxiliary unit; 300, drive control module; 310, feedback control unit; 320, abnormal protection unit. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] At present, traditional power conversion devices have certain limitations in terms of efficiency, volume and weight, and are difficult to meet the growing high-performance requirements of modern aerospace vehicles. In order to use three-level technology to convert the input DC voltage into the required output DC voltage and improve the power conversion efficiency, soft switching technology is used to assist in controlling the opening and closing of the switch tube, reduce switching losses, and ensure that the device meets the high standards of aerospace vehicles.

[0041] Therefore, the present invention proposes to filter the input voltage through an input filter module to eliminate high-frequency noise and clutter in the input voltage and maintain the stability of the input voltage; use a voltage conversion module to convert the input DC voltage into the required output DC voltage; and use a soft-switching auxiliary control circuit to ensure that the switch tube switches under zero voltage and zero current conditions. The drive control module adopts a voltage and current dual closed-loop control strategy to generate a PWM pulse signal to control the on and off of the switch tube in the three-level voltage conversion circuit, adopts overvoltage protection, overcurrent protection and overheating protection, detects the current and voltage status, and when an abnormal situation is detected, the control circuit can quickly take corresponding protection measures.

[0042] The details are as follows:

[0043] See also Figure 1 As shown, the present invention provides a high-efficiency power conversion device for aerospace vehicles based on three-level technology. Figure 6 Showing the structure, the power conversion device includes an input filter module 100, a voltage conversion module 200 and a drive control module 300;

[0044] The input filter module 100 filters the input voltage through the input filter circuit, using the virtual short and virtual open functions of the operational amplifier A to eliminate high-frequency noise and clutter in the input voltage, and transmits the processed voltage to the voltage conversion module 200;

[0045] The voltage conversion module 200 converts the input DC voltage into the required output DC voltage through a three-level voltage conversion circuit. It uses a space vector pulse width modulation strategy to optimize the switching sequence and switching timing of the switch tubes to reduce switching losses. It uses a soft switching auxiliary control circuit to enable the switch tubes to switch under zero voltage and zero current conditions. It uses active clamping soft switching technology to add auxiliary switch tubes and clamping capacitor elements to the main circuit to assist in controlling the switch tubes of the three-level voltage conversion circuit.

[0046] The drive control module 300 uses a digital signal processor as the core control unit, adopts a voltage and current dual closed-loop control strategy, generates a PWM pulse signal, controls the on and off of the switch tube in the three-level voltage conversion circuit, adopts overvoltage protection, overcurrent protection and overheating protection, and detects the current and voltage status.

[0047] Three-level technology refers to a technology that enables the output voltage or current to have three levels in power electronic converters. Taking a three-level inverter as an example, its output voltage can usually present three states: positive level, zero level, and negative level. Compared with the traditional two-level inverter, which only has two states, positive and negative level, it also has an additional zero level state.

[0048] At the same output voltage and power level, the voltage stress borne by each switching device in a three-level converter is only half that of the switching device in a two-level converter. Therefore, switching devices with lower withstand voltage values ​​can be selected, which reduces the requirements for the devices. As the number of output levels increases, the output voltage waveform becomes closer to a sine wave, and the harmonic content is significantly reduced, which can effectively reduce the size and cost of the output filter and improve the performance and reliability of the system. Switching loss is related to the voltage stress and switching frequency of the switching device. Three-level technology reduces voltage stress, which can reduce switching loss to a certain extent and improve the conversion efficiency of the system.

[0049] Specific as Figure 7As shown, the switching frequency varies with load, decreasing at light loads. The output voltage exhibits positive, zero, and negative levels (as shown in the CH1 waveform). CH3 (resonant current) crosses zero at the switching point, indicating zero current shutdown (ZCS). The level switching sequence in the waveform reflects the optimized switching sequence, reducing switching transitions and losses, verifying the light-load efficiency optimization and soft switching effectiveness.

[0050] like Figure 8 As shown, the waveform directly reflects the reduction of output voltage harmonics, reducing the filter size. The level switching sequence conforms to the dynamic vector combination selection and adapts to real-time load changes. It proves that harmonics are reduced by more than 50%, supporting the advantages of "high efficiency and low noise";

[0051] Therefore, the experimental waveform verifies that:

[0052] Three-level technology significantly improves output waveform quality (reduced harmonics and improved efficiency);

[0053] Soft switching + space vector modulation synergistically reduce switching losses;

[0054] Dual mode (PFM / PWM) adapts to the wide load range requirements of spacecraft and improves system reliability.

[0055] like Figure 3 As shown, the input filtering module 100 includes an input filtering circuit, wherein the input filtering circuit includes an operational amplifier A;

[0056] Pin 2 of operational amplifier A is connected to one end of resistor R1, and is connected in parallel to one end of resistor R3 and one end of capacitor C1. The other end of resistor R1 is connected to input voltage UI. Pin 3 of operational amplifier A is connected to one end of resistor R2, and the other end of resistor R2 is grounded. Pin 1 of operational amplifier A is connected to the other end of resistor R3 and the other end of capacitor C1, and is connected in parallel to output voltage UO.

[0057] In this circuit, according to the virtual short and virtual open characteristics of operational amplifier A, the voltages at the non-inverting input terminal 2 and the inverting input terminal 1 are approximately equal (virtual short), and the current flowing into the inverting input terminal 1 is approximately zero (virtual open). The input voltage passes through the low-pass filter network composed of resistor R3 and capacitor C1 to perform low-pass filtering on the input voltage, eliminating high-frequency noise and clutter in the input voltage and maintaining the stability of the input voltage.

[0058] like Figure 2 As shown, the voltage conversion module 200 includes a DC conversion unit 210 and a soft switching auxiliary unit 220;

[0059] The DC conversion unit 210 switches the output voltage between positive level, zero level and negative level through different switch combinations in the three-level voltage conversion circuit, and reduces switching loss by using three-level output;

[0060] The soft switching auxiliary unit 220 uses a soft switching auxiliary control circuit to enable the switch tube to switch under zero voltage and zero current conditions, thereby assisting in regulating the switch tube of the three-level voltage conversion circuit;

[0061] Soft switching technology refers to the process of switching the switch tube under zero voltage (ZVS) or zero current (ZCS) conditions by introducing resonance or auxiliary circuits during the switching process, thereby effectively reducing switching losses and improving power conversion efficiency.

[0062] In order to better convert the input voltage into the required output voltage, such as Figure 4 As shown, the DC conversion unit 210 includes a three-level voltage conversion circuit, wherein the three-level voltage conversion circuit includes a switch tube S1, a switch tube S2, a switch tube S3, a switch tube S4 and an inductor L1;

[0063] The gate of the switch tube S1 is connected to the anode of the diode D2 and the anode of the diode D3 in parallel. The cathodes of the diode D2 and the cathode of the diode D3 are connected to the input voltage UI. The drain of the switch tube S1 is connected to the gate of the switch tube S2 and the cathode of the diode D6 in parallel. The drain of the switch tube S2 is connected to the cathode of the diode D1 and the cathode of the diode D4 in parallel to the gate of the switch tube S3. The drain of the switch tube S3 is connected to the cathode of the diode D5 and the gate of the switch tube S4 in parallel. The drain of the switch tube S4 is connected to one end of the capacitor C2. The other end of the capacitor C2 is connected to the anode of the diode D5 and the anode of the diode D6 in parallel to the capacitor C3.

[0064] The drain of the switch tube S2 is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to one end of the capacitor C5 and connected to the output voltage UO, and the other end of the capacitor C5 is connected to the anode of the diode D5 and the anode of the diode D6.

[0065] In this circuit, when switches S1 and S2 are turned on and switches S3 and S4 are turned off, if the load current is positive, the current flows from the positive electrode of the DC power supply through switches S1 and S2 to the output terminal. At this time, the voltage of the output terminal relative to the midpoint is If the load current is negative, the current flows from the output end and flows back to the DC power supply through the diode D6 connected in anti-parallel with the switch tube S1 and the switch tube S2. The output voltage remains At this time, the output is positive level;

[0066] When switches S2 and S3 are turned on and switches S1 and S4 are turned off, if the load current is positive, the current flows out of the positive electrode of the DC power supply, through switch S2 and diode D6, and flows to the output terminal. At this time, the voltage of the output terminal relative to the midpoint is 0. If the load current is negative, the current flows into the output terminal, through switch S3 and diode D5, and flows back to the midpoint of the DC power supply. The output voltage is also 0, and the output is zero level.

[0067] When the switch tubes S3 and S4 are turned on and the switch tubes S1 and S2 are turned off, if the load current is positive, the current flows out from the midpoint of the DC power supply, through the diode D5 and the switch tube S3 to the output end. At this time, the voltage of the output end relative to the midpoint is If the load current is negative, the current flows from the output end, flows back to the negative pole of the DC power supply through the switch tube S4 and the diode D5 connected in anti-parallel with the switch tube S4, and the output end voltage is At this time, the output is negative level;

[0068] Through the three-level voltage conversion circuit, the switching tubes are divided into three groups: upper, middle and lower. Through different switch combinations, the output voltage can be switched between positive level, zero level and negative level, thereby realizing three-level output and enabling the switching tubes to switch under zero voltage or zero current conditions, greatly reducing switching losses and improving power conversion efficiency.

[0069] To better control the switching sequence of the switches, the DC converter unit 210 uses a space vector pulse width modulation strategy to optimize the switching sequence of the switches. By introducing redundant vectors, a new vector combination is synthesized, and the most appropriate basic voltage vector combination is dynamically selected according to the real-time changes in the load.

[0070] The traditional space vector pulse width modulation (SVPWM) strategy synthesizes the reference voltage vector through the basic voltage vector, usually using two adjacent non-zero vectors and one zero vector. However, this approach may not be optimal and may lead to unnecessary switching actions.

[0071] The improved SVPWM can find a more optimal vector synthesis combination. For example, it introduces the rational use of redundant vectors and selects the combination with the least number of switching operations among multiple vector combinations that can synthesize the reference voltage vector. This can reduce the number of times the switch is turned on and off, thereby reducing switching losses.

[0072] Based on the real-time changes in the load, the most appropriate basic voltage vector is dynamically selected for synthesis. For example, when the load current is small, vector combinations that can reduce switching losses are prioritized. When the load changes rapidly, the vector synthesis method is quickly adjusted to ensure the stability of the output voltage.

[0073] In order to better reduce switching jumps, the DC conversion unit 210 optimizes the switching sequence of the switch tubes by designing a symmetrical switching sequence to make the on and off time distribution of the switch tubes more uniform and reduce the switching state jumps between two adjacent sampling periods;

[0074] The switching sequence of traditional SVPWM may cause some switches to switch frequently, increasing switching losses. Designing a symmetrical switching sequence makes the on and off time distribution of the switch tube more uniform, making the on and off states of the switch tube symmetrical within a switching cycle. This can reduce thermal stress concentration on the switch tube and reduce switching losses.

[0075] Optimize the switching sequence to minimize the switching state jump between two adjacent sampling cycles. For example, by reasonably arranging the action sequence of the basic voltage vector, avoid the switch tube frequently switching from on to off or from off to on in a short period of time, thereby reducing energy loss during the switching process.

[0076] like Figure 5 As shown, the soft switching auxiliary unit 220 includes a soft switching auxiliary control circuit, wherein the soft switching auxiliary control circuit includes an inductor L2, a switch tube S5 and a diode D7;

[0077] The gate of the switch tube S5 is connected to the input voltage UI, the drain of the switch tube S5 is connected to one end of the inductor L2 and in parallel to the anode of the diode D7, the cathode of the diode D7 is connected to one end of the capacitor C6 and in parallel to one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C6 and in parallel to the output voltage UO;

[0078] In this circuit, capacitor C6 is used to store and release energy. It clamps the voltage and provides energy during the on / off process of switch S5. Resonant inductor L2 and capacitor C6 form a resonant circuit. When switch S5 is turned off, a resonant current is generated, achieving zero-current shutdown.

[0079] The control signal of the auxiliary switch tube S5 cooperates with the control signal of the main switch tube of the three-level voltage conversion circuit to achieve soft switching of the main switch tube through reasonable timing control. The switch tube switches under zero voltage (ZVS) or zero current (ZCS) conditions, thereby effectively reducing switching losses and improving power conversion efficiency.

[0080] To achieve zero voltage turn-on, the soft switching auxiliary unit 220 uses the inductor L2 and the capacitor C6 to form a resonant network, so that the voltage across the main switch S5 changes according to a sinusoidal law, ensuring that the voltage across the main switch S5 is exactly zero when it is turned on next time.

[0081] By adjusting the switching timing of the switch tube to achieve zero voltage turn-on and zero current turn-off as much as possible, an auxiliary resonant circuit is introduced into the circuit, and combined with an improved SVPWM strategy, the switch tube switches when the voltage or current is zero. For example, before the switch tube is turned on, the resonant circuit is used to reduce the voltage across it to zero, and then the switch tube is turned on. This can avoid voltage and current overlap and significantly reduce switching losses.

[0082] The system adaptively adjusts the switching timing of the switching tube based on real-time parameters such as the power supply's input voltage and output load. For example, when the input voltage increases, the switching timing of the switching tube is appropriately advanced or delayed to ensure low switching losses under different operating conditions.

[0083] The drive control module 300 includes a feedback control unit 310 and an abnormality protection unit 320;

[0084] The feedback control unit 310 adopts a voltage and current dual closed-loop control strategy to generate a PWM pulse signal to control the on and off of the switch tube in the three-level voltage conversion circuit;

[0085] The abnormality protection unit 320 adopts overvoltage protection, overcurrent protection and overheat protection, detects the status of current and voltage, monitors abnormal status, and issues early warning indications;

[0086] The digital signal processor samples and processes feedback signals such as input and output voltage and current, generating PWM pulse signals based on a preset control algorithm to control the on and off switching of the switches in the three-level DC / DC converter. The control algorithm employs a dual closed-loop voltage and current control strategy, with the voltage loop serving as the outer loop to stabilize the output voltage and the current loop serving as the inner loop to rapidly track load current changes, improving the system's dynamic response performance.

[0087] In order to better regulate the error signal, when the feedback control unit 310 adopts a voltage-current dual closed-loop control strategy, a nested control structure is adopted, including a voltage outer loop and a current inner loop, and a voltage regulator is used to regulate the error signal;

[0088] The voltage-current dual closed-loop control strategy uses a nested control structure, consisting of a voltage outer loop and a current inner loop. The voltage outer loop is responsible for stabilizing the output voltage, comparing the actual output voltage with the given voltage to obtain a voltage error signal. This error signal is processed by a voltage regulator (such as a PI regulator) to generate a current given signal. The current inner loop is responsible for tracking the current given signal, comparing the actual current with the current given signal to obtain a current error signal. After processing by the current regulator, it generates a PWM (pulse width modulation) signal to control the switch tube, thereby controlling the conduction and shutdown of the switch tube and achieving precise control of the output voltage and current.

[0089] The voltage outer loop can stabilize the output voltage, and the current inner loop can limit the current to prevent overcurrent from damaging the device. The combination of the two can effectively improve the stability of the system, so that the system can maintain stable operation under different loads and input voltage changes;

[0090] The current inner loop has a fast response speed and can quickly track changes in the current given signal, so that the system can quickly adjust the output current when the load changes suddenly, reducing the fluctuation of the output voltage. The voltage outer loop can accurately adjust the output voltage over a long period of time to ensure the stability of the output voltage.

[0091] The dual closed-loop control strategy effectively suppresses both internal and external interference. For example, when the input voltage fluctuates, the outer voltage loop adjusts the current reference signal, enabling the inner current loop to adjust the output current, thereby maintaining a stable output voltage. When the load changes, the inner current loop responds quickly, minimizing output voltage fluctuations.

[0092] In summary, the working principle of this solution is as follows:

[0093] This high-efficiency power conversion device for aerospace vehicles based on three-level technology filters the input voltage through the input filter module 100 to eliminate high-frequency noise and clutter in the input voltage and maintain the stability of the input voltage. The input DC voltage is converted into the required output DC voltage by the voltage conversion module 200. The space vector pulse width modulation strategy is adopted to optimize the switching sequence and switching time of the switch tube to reduce switching loss. The soft switching auxiliary control circuit ensures that the switch tube switches under zero voltage and zero current conditions, realizes zero voltage turn-on and zero current turn-off of the switch tube, avoids the overlap of voltage and current, and greatly reduces the switching loss. The drive control module 300 adopts a voltage-current dual closed-loop control strategy to generate a PWM pulse signal to control the on and off of the switch tube in the three-level voltage conversion circuit. The voltage loop is used as the outer loop to stabilize the output voltage, and the current loop is used as the inner loop to quickly track the load current changes, thereby improving the dynamic response performance of the system. Overvoltage protection, overcurrent protection and overheating protection are adopted to detect the status of current and voltage. When an abnormal situation is detected, the control circuit can quickly take corresponding protection measures to turn off the switch tube and send out an alarm signal to avoid damage to the power conversion device and other equipment of the aerospace vehicle.

[0094] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency power conversion device for aerospace vehicles based on three-level technology, characterized by: It includes an input filter module (100), a voltage conversion module (200) and a drive control module (300); The input filter module (100) filters the input voltage through an input filter circuit, utilizes the virtual short and virtual open functions of the operational amplifier A to eliminate high-frequency noise and clutter in the input voltage, and transmits the processed voltage to the voltage conversion module (200); The voltage conversion module (200) converts an input DC voltage into a required output DC voltage through a three-level voltage conversion circuit, adopts a space vector pulse width modulation strategy to optimize the switching sequence and switching time of the switch tube, reduces switching loss, utilizes a soft switch auxiliary control circuit to enable the switch tube to switch under zero voltage and zero current conditions, and adopts active clamping soft switching technology to add auxiliary switch tubes and clamping capacitor elements in the main circuit to assist in regulating the switch tube of the three-level voltage conversion circuit; The drive control module (300) uses a digital signal processor as a core control unit, adopts a voltage and current dual closed-loop control strategy, generates a PWM pulse signal, controls the on and off of a switch tube in a three-level voltage conversion circuit, adopts overvoltage protection, overcurrent protection and overheating protection, and detects the state of current and voltage.

2. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 1, characterized in that: The input filter module (100) comprises an input filter circuit, wherein the input filter circuit comprises an operational amplifier A; Pin 2 of the operational amplifier A is connected to one end of the resistor R1, and is connected in parallel to one end of the resistor R3 and one end of the capacitor C1. The other end of the resistor R1 is connected to the input voltage UI. Pin 3 of the operational amplifier A is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded. Pin 1 of the operational amplifier A is connected to the other end of the resistor R3 and the other end of the capacitor C1, and is connected in parallel to the output voltage UO.

3. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 1, characterized in that: The voltage conversion module (200) comprises a direct current conversion unit (210) and a soft switch auxiliary unit (220); The DC conversion unit (210) switches the output voltage between a positive level, a zero level, and a negative level through different switch combinations in a three-level voltage conversion circuit, and utilizes three-level output to reduce switching losses. The soft switch auxiliary unit (220) uses a soft switch auxiliary control circuit to enable the switch tube to switch under the conditions of zero voltage and zero current, thereby assisting in regulating the switch tube of the three-level voltage conversion circuit.

4. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 3, characterized in that: The DC conversion unit (210) comprises a three-level voltage conversion circuit, wherein the three-level voltage conversion circuit comprises a switch tube S1, a switch tube S2, a switch tube S3, a switch tube S4 and an inductor L1; The gate of the switch tube S1 is connected to the anode of the diode D2 and the anode of the diode D3, the cathode of the diode D2 and the cathode of the diode D3 are connected to the input voltage UI, the drain of the switch tube S1 is connected to the gate of the switch tube S2 and the cathode of the diode D6, the drain of the switch tube S2 is connected to the cathode of the diode D1 and the cathode of the diode D4, and the gate of the switch tube S3, the drain of the switch tube S3 is connected to the cathode of the diode D5 and the gate of the switch tube S4, the drain of the switch tube S4 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to the anode of the diode D5 and the anode of the diode D6, and the capacitor C3; The drain of the switch tube S2 is connected to one end of the inductor L1, the other end of the inductor L1 is connected to one end of the capacitor C4, the other end of the capacitor C4 is connected to one end of the capacitor C5 and connected to the output voltage UO, and the other end of the capacitor C5 is connected to the anode of the diode D5 and the anode of the diode D6.

5. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 3, characterized in that: The DC conversion unit (210) adopts a space vector pulse width modulation strategy to optimize the switching sequence of the switch tubes, introduces redundant vectors to synthesize a new vector combination, and dynamically selects the most appropriate basic voltage vector combination according to the real-time change of the load.

6. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 5, characterized in that: When optimizing the switching sequence of the switch tubes, the DC conversion unit (210) designs a symmetrical switching sequence, thereby making the on and off time distribution of the switch tubes more uniform and reducing the switching state jump between two adjacent sampling periods.

7. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 3, characterized in that: The soft switch auxiliary unit (220) includes a soft switch auxiliary control circuit, wherein the soft switch auxiliary control circuit includes an inductor L2, a switch tube S5 and a diode D7; The gate of the switch tube S5 is connected to the input voltage UI, the drain of the switch tube S5 is connected to one end of the inductor L2 and the anode of the diode D7, the cathode of the diode D7 is connected to one end of the capacitor C6 and one end of the resistor R4, the other end of the resistor R4 is connected to one end of the capacitor C6 and the output voltage UO.

8. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 7, characterized in that: The soft switching auxiliary unit (220) uses an inductor L2 and a capacitor C6 to form a resonant network, so that the voltage across the main switch tube S5 changes according to a sinusoidal law, so that the voltage across the main switch tube S5 is exactly zero when the main switch tube S5 is turned on next time.

9. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 1, characterized in that: The drive control module (300) includes a feedback control unit (310) and an abnormality protection unit (320); The feedback control unit (310) adopts a voltage and current dual closed-loop control strategy to generate a PWM pulse signal to control the on and off of a switch tube in a three-level voltage conversion circuit; The abnormality protection unit (320) adopts overvoltage protection, overcurrent protection and overheat protection, detects the state of current and voltage, monitors the abnormal state, and issues an early warning indication.

10. The high-efficiency power conversion device for aerospace vehicles based on three-level technology according to claim 9, characterized in that: When the feedback control unit (310) adopts a voltage-current dual closed-loop control strategy, a nested control structure is adopted, including a voltage outer loop and a current inner loop, and a voltage regulator is used to adjust the error signal.

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