Aviation power panel assembly based on modular redundant architecture

Abstract

The invention provides an aviation power panel assembly based on a modular redundant architecture. The aviation power panel assembly comprises an input protection unit, a core power unit, an intelligent monitoring unit and a redundant power supply system, the input protection unit is composed of a double-TVS series peak suppression module, a three-stage EMI filter and an NMOS surge suppression module. The double-TVS series peak suppression module comprises a TVS1 connected in the forward direction and a TVS2 connected in the reverse direction, and the TVS1 and the TVS2 are connected to the two ends of an input power circuit in parallel. The three-stage EMI filter is formed by cascading a first-stage common-mode filter and a second-stage differential-mode filter, the common-mode filter adopts a symmetrical double-Y capacitor layout, and the differential-mode filter is provided with a magnetic saturation early warning circuit; the NMOS surge suppression module comprises a dynamic grid voltage control circuit, and the grid voltage establishment time is controlled to be 500 microseconds to 50 milliseconds through an adjustable time constant circuit; the core power unit comprises a half-brick type 270V-to-28V module, a 28V-to-5V module and a double-path 1 / 16-brick type 28V-to-5.5 V module; and the half-brick type 270V-to-28V module adopts a BUCK pre-voltage-stabilizing stage and full-bridge isolation cascade topology.

Description

Technical Field

[0001] The present invention belongs to the field of power board assemblies, and particularly relates to an aviation power board assembly based on a modular redundant architecture. Background Art

[0002] In modern avionics systems, as the core power supply unit, the performance and reliability of the power board assembly are directly related to flight safety and system stability. However, with the increasing complexity of avionics equipment and the increasingly harsh flight environment, traditional power board assemblies face many challenges in design and performance.

[0003] The redundant design of traditional power systems usually adopts a simple parallel backup method, lacking an intelligent switching mechanism, resulting in too long switching time when the main power fails, affecting system continuity. Most of the power conversion modules in the prior art adopt a single-path design, and once a failure occurs, the entire system will power off, unable to meet the requirements of avionics equipment for high reliability and continuity.

[0004] The electromagnetic compatibility design of traditional power board assemblies is insufficient, making it difficult to cope with high-frequency noise and surge interference in complex electromagnetic environments, and easily leading to system performance degradation or even failure. In terms of output noise and ripple suppression, the prior art mostly adopts a first-order LC filter structure, and the filtering effect is limited (usually ≤ 20dB), making it difficult to meet the high requirements of avionics equipment for power quality. In terms of power-off maintenance design, traditional solutions mostly use large-capacity capacitors for direct power supply, resulting in low energy utilization efficiency and short maintenance time, and unable to meet the long-time power supply requirements of avionics equipment in emergency situations.

[0005] In addition, existing power systems usually design the input protection, power conversion, and output noise suppression modules separately, resulting in complex interfaces, low efficiency, and insufficient reliability, increasing the difficulty of system integration and debugging. The efficiency of the core power conversion module is relatively low (usually ≤ 80%), and it is difficult to meet the application requirements of a wide input voltage range (9V - 36V), resulting in unstable system performance when the input voltage fluctuates. In terms of thermal management, traditional power board assemblies lack an efficient thermal design and are prone to overheating problems under high loads, affecting system life and reliability. In summary, traditional power board assemblies have obvious deficiencies in redundant design, power conversion, electromagnetic compatibility, output noise suppression, power-off maintenance management, overall architecture design, and thermal management, and it is urgent to develop an innovative power board assembly design solution based on a modular redundant architecture to solve the above problems. Summary of the Invention

[0006] The present invention proposes an aviation power board assembly based on a modular redundant architecture, which solves the deficiencies of traditional power supply systems in terms of spike suppression, EMI filtering, surge suppression, power conversion efficiency, redundant power supply and intelligent monitoring, and improves the reliability, stability and anti-interference ability of the aviation power supply system.

[0007] The technical solution of the present invention is implemented as follows: an aviation power supply board assembly based on a modular redundant architecture includes an input protection unit, a core power unit, an intelligent monitoring unit and a redundant power supply system;

[0008] The input protection unit is composed of a dual TVS series spike suppression module, a three-stage EMI filter and an NMOS surge suppression module; the dual TVS series spike suppression module includes a forward-connected TVS1 and a reverse-connected TVS2, which are connected in parallel at both ends of the input power supply line; the three-stage EMI filter is composed of a 1st-stage common-mode filter and a 2nd-stage differential-mode filter in cascade, the common-mode filter adopts a symmetrical dual-Y capacitor layout, and the differential-mode filter is provided with a magnetic saturation warning circuit; the NMOS surge suppression module includes a dynamic gate voltage control circuit, and the gate voltage establishment time is controlled to be 500μs-50ms through an adjustable time constant circuit;

[0009] The core power unit includes a half-brick 270V to 28V module, a 28V to 5V module and a dual-channel 1 / 16 brick 28V to 5.5V module; the half-brick 270V to 28V module adopts a BUCK pre-regulator stage and a full-bridge isolation cascade topology, and the input voltage range is 140-400V; the 28V to 5V module adopts a single-ended flyback topology with a built-in synchronous rectifier MOS tube; the 28V to 5.5V module adopts an active clamp flyback topology and includes a body diode reverse recovery suppression circuit;

[0010] The intelligent monitoring unit includes a four-channel voltage state comparator, an optocoupler isolation digital communication module and a power-off maintenance circuit; the voltage state comparator is provided with four independent detection channels, each channel includes a window comparison circuit and a hysteresis comparison circuit; the optocoupler isolation digital communication module supports TTL / LVTTL level conversion, and the transmission delay is less than 100ns; the power-off maintenance circuit adopts a hybrid energy storage structure of supercapacitor and lithium-ion battery;

[0011] The redundant power supply system consists of a four-way OR-ing topology, including a 28V maintenance power supply, a 270V external power supply, and four inputs of onboard 28V power supplies I and II. Each OR-ing branch is equipped with an ideal diode controller with an on-resistance of less than 5mΩ and a built-in fault isolation switch. Each branch is equipped with a Hall current sensor with a sampling accuracy of ±1%.

[0012] In the prior art, a single TVS tube is mostly adopted for spike suppression, with limited suppression ability and difficulty in coping with bidirectional spike voltages. In this solution, a dual TVS series spike suppression module (with a forward TVS1 and a reverse TVS2 in parallel) significantly improves the suppression ability of bidirectional spike voltages. At the same time, the three-stage EMI filter adopts a cascaded design of a first-stage common-mode filter and a second-stage differential-mode filter, combined with a symmetric dual-Y capacitor layout and a magnetic saturation warning circuit, further improving the electromagnetic compatibility and filtering effect. In addition, the NMOS surge suppression module realizes precise control of surge current through a dynamic gate voltage control circuit and an adjustable time constant circuit (500 μs - 50 ms), avoiding the problems of slow surge suppression response and high power consumption in the traditional solution.

[0013] Traditional power conversion modules mostly adopt a single topology structure, which is difficult to meet the requirements of a wide input voltage range and high efficiency. In this solution, through a multi-topology combination design of a half-brick 270V to 28V module (BUCK pre-regulator stage and full-bridge isolation cascaded topology), a 28V to 5V module (single-ended flyback topology structure), and a 28V to 5.5V module (active clamp flyback topology), the power conversion efficiency (≥90%) and input voltage adaptability (140 - 400V) are significantly improved. At the same time, the 28V to 5.5V module is built-in with a body diode reverse recovery suppression circuit, further reducing the switching loss and electromagnetic interference.

[0014] Traditional power conversion modules mostly adopt a single topology structure, which is difficult to meet the requirements of a wide input voltage range and high efficiency. In this solution, through a multi-topology combination design of a half-brick 270V to 28V module (BUCK pre-regulator stage and full-bridge isolation cascaded topology), a 28V to 5V module (single-ended flyback topology structure), and a 28V to 5.5V module (active clamp flyback topology), the power conversion efficiency (≥90%) and input voltage adaptability (140 - 400V) are significantly improved. At the same time, the 28V to 5.5V module is built-in with a body diode reverse recovery suppression circuit, further reducing the switching loss and electromagnetic interference.

[0015] Traditional redundant power supply systems mostly adopt a dual-channel OR-ing design, with insufficient redundancy and a lack of a fault isolation mechanism. In this solution, through a four-channel OR-ing topology (28V maintenance power supply, 270V external power supply, airborne 28V power supply I and II), combined with an ideal diode controller (on-resistance <5 mΩ) and a fault isolation switch, high redundancy and high-reliability power supply are achieved. At the same time, each branch is configured with a Hall current sensor (sampling accuracy ±1%), further improving the accuracy of current monitoring.

[0016] As a preferred embodiment, it further includes a three-dimensional heat dissipation structure, which comprises a gold-plated copper substrate, a thermally conductive silicone grease filling layer, and corrugated heat dissipation fins; the gold-plated copper substrate has a thickness of 0.8 mm and is directly connected to the bottom of the power module by screws; the thermally conductive silicone grease filling layer has a thermal conductivity of ≥5 W / m·K, and the covered area accounts for 85% of the surface area of the PCB substrate; the corrugated heat dissipation fins have a height of 8 mm and are arranged on the PCB with a spacing of 2 mm.

[0017] As a preferred embodiment, the PCB substrate adopts a six-layer stacked structure, and the layer sequence is signal layer - power supply layer - ground layer - power supply layer - signal layer - protection layer; the key signal lines adopt stripline layout, and the characteristic impedance is controlled within 50Ω ± 5%; the power trace width is ≥3 mm, and the copper cladding thickness is 2 oz.

[0018] As a preferred embodiment, it further includes a status monitoring system, which comprises a voltage ripple spectrum analysis module, a distributed thermal sensor array, and a load transient response test circuit; the spectrum analysis module has a sampling bandwidth of 20 MHz and 1024 FFT analysis points; the thermal sensor array includes 8 PT1000 sensors, which are arranged on the surface of the power module; the load transient response test circuit can generate a step load of 1 A / μs.

[0019] As a preferred embodiment, the ideal diode controller includes a comparator module, a drive circuit, and a fault feedback loop; the input voltage difference is monitored in real time through the comparator module, and when the voltage difference exceeds 5 mV, the fast switching circuit is activated. The drive circuit uses a charge pump technology to provide a negative bias voltage to ensure that the MOS transistor is completely turned off; the fault feedback loop transmits the status signal to the monitoring unit through a digital isolator.

[0020] As a preferred embodiment, the active clamp flyback topology forms an energy recovery branch by connecting a clamp capacitor in series with the MOS transistor, and through a synchronous rectifier drive signal delay compensation circuit, the compensation time is adjustable from 50 to 150 ns. The leakage inductance energy absorption circuit therein is composed of a transient voltage suppressor and an RC buffer network connected in parallel.

[0021] As a preferred embodiment, the dynamic gate voltage control circuit includes a programmable timer chip, an SOA protection module, and a temperature compensation circuit. The programmable timer chip adjusts the time constant through an external capacitor; the SOA protection module collects the drain-source voltage and drain current in real time, and forcibly turns off when the operating point exceeds the SOA curve; the temperature compensation circuit adjusts the slope of the gate drive voltage according to the junction temperature.

[0022] After adopting the above technical solutions, the beneficial effects of the present invention are as follows: Through innovative designs such as a dual TVS series spike suppression module, a three-stage EMI filter, an NMOS surge suppression module, an efficient power conversion topology, an intelligent monitoring unit, and a four-way OR-ing redundant power supply system, the performance and reliability of the power supply system are significantly improved. First, the dual TVS series spike suppression module significantly enhances the suppression ability of bidirectional spike voltages through the parallel design of forward TVS1 and reverse TVS2. At the same time, the three-stage EMI filter, through the cascade design of a first-stage common-mode filter and a second-stage differential-mode filter, combined with a symmetric dual-Y capacitor layout and a magnetic saturation warning circuit, further improves the electromagnetic compatibility and filtering effect. Second, the NMOS surge suppression module realizes precise control of surge current through a dynamic gate voltage control circuit and an adjustable time constant circuit (500 μs - 50 ms), avoiding the problems of slow surge suppression response and high power consumption in traditional solutions. Third, the core power unit, through a multi-topology combination design of a half-brick 270V to 28V module (BUCK pre-regulator stage and full-bridge isolation cascade topology), a 28V to 5V module (single-ended flyback topology), and a 28V to 5.5V module (active-clamped flyback topology), significantly improves the power conversion efficiency (≥90%) and input voltage adaptability (140 - 400V). At the same time, the 28V to 5.5V module is built with a body diode reverse recovery suppression circuit, further reducing the switching loss and electromagnetic interference. Fourth, the intelligent monitoring unit realizes real-time monitoring of voltage status, high-speed communication, and long-time power-off maintenance through the multi-functional integration of a four-channel voltage status comparator, an opto-isolated digital communication module, and a power-off maintenance circuit, significantly improving the intelligence and reliability of the system. Fifth, the redundant power supply system, through a four-way OR-ing topology (28V maintenance power supply, 270V external power supply, airborne 28V power supply I and II), combined with an ideal diode controller (on-resistance <5 mΩ) and a fault isolation switch, realizes high-redundancy and high-reliability power supply. At the same time, each branch is equipped with a Hall current sensor (sampling accuracy ±1%), further improving the accuracy of current monitoring. In summary, this power board assembly has significant advantages in spike suppression, EMI filtering, surge suppression, power conversion efficiency, redundant power supply, and intelligent monitoring, and is suitable for application scenarios of high-reliability and high-stability aviation power supply systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1This is the block diagram of the component system of the present invention.

[0025] Figure 2 This is the functional principle block diagram of the overall design of the present invention.

[0026] Figure 3 This is the schematic diagram of the input EMI electromagnetic compatibility and power supply characteristic design part of the present invention.

[0027] Figure 4 This is the schematic diagram of the EMI filter (common mode filter + differential mode filter) of the present invention.

[0028] Figure 5 This is the schematic diagram of the drain-source voltage V of the power switch Q1 at the moment of power-on startup of the present invention. DS Schematic diagram.

[0029] Figure 6 This is the schematic diagram of the safe operating area SOA of the power switch Q1 of the present invention.

[0030] Figure 7 This is the schematic diagram of the surge suppressor with ideal diode control function of the present invention.

[0031] Figure 8 This is the schematic diagram of the OR-ing redundancy design of the present invention.

[0032] Figure 9 This is the diagram of the 140V~400V input BUCK / Full Bridge / Synchronous Rectification topology structure (28V / 14.3A) of the present invention.

[0033] Figure 10 This is the diagram of the 9V~36V input single-ended flyback / synchronous rectification topology structure (5V / 1A) of the present invention.

[0034] Figure 11 This is the diagram of the 9V~36V input single-ended flyback / active clamp / synchronous rectification topology structure (5.5V / 10A) of the present invention.

[0035] Figure 12 This is the simulation model diagram of the output voltage tolerance analysis of the isolated DC / DC power conversion of the present invention.

[0036] Figure 13 This is the simulation diagram of the VOUT output voltage waveform of the present invention.

[0037] Figure 14 This is the Monte Carlo histogram of the VOUT output voltage of the present invention.

[0038] Figure 15 This is the principle block diagram of the power-off maintenance design in the embodiment of the present invention.

[0039] Figure 16 This is the reliability functional block diagram of the product in the embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0041] Example:

[0042] like Figures 1 - 16 As shown, the aviation power board assembly based on the modular redundant architecture includes an input protection unit, a core power unit, an intelligent monitoring unit and a redundant power supply system;

[0043] The input protection unit is composed of a dual TVS series spike suppression module, a three-stage EMI filter and an NMOS surge suppression module; the dual TVS series spike suppression module includes a forward-connected TVS1 and a reverse-connected TVS2, which are connected in parallel at both ends of the input power supply line; the three-stage EMI filter is composed of a 1st-stage common-mode filter and a 2nd-stage differential-mode filter in cascade, the common-mode filter adopts a symmetrical dual-Y capacitor layout, and the differential-mode filter is provided with a magnetic saturation warning circuit; the NMOS surge suppression module includes a dynamic gate voltage control circuit, and the gate voltage establishment time is controlled to be 500μs-50ms through an adjustable time constant circuit;

[0044] The core power unit includes a half-brick 270V to 28V module, a 28V to 5V module and a dual-channel 1 / 16 brick 28V to 5.5V module; the half-brick 270V to 28V module adopts a BUCK pre-regulator stage and a full-bridge isolation cascade topology, and the input voltage range is 140-400V; the 28V to 5V module adopts a single-ended flyback topology with a built-in synchronous rectifier MOS tube; the 28V to 5.5V module adopts an active clamp flyback topology and includes a body diode reverse recovery suppression circuit;

[0045] The intelligent monitoring unit includes a four-channel voltage state comparator, an optocoupler isolation digital communication module and a power-off maintenance circuit; the voltage state comparator is provided with four independent detection channels, each channel includes a window comparison circuit and a hysteresis comparison circuit; the optocoupler isolation digital communication module supports TTL / LVTTL level conversion, and the transmission delay is less than 100ns; the power-off maintenance circuit adopts a hybrid energy storage structure of supercapacitor and lithium-ion battery;

[0046] The redundant power supply system consists of four OR-ing topologies, including four inputs: 28V maintenance power supply, 270V external power supply, airborne 28V power supply I and II. Each OR-ing branch is configured with an ideal diode controller with a conduction resistance lower than 5mΩ and an internal fault isolation switch. Hall current sensors are set in each branch with a sampling accuracy of ±1%.

[0047] The input EMI electromagnetic compatibility / power characteristics design mainly includes input spike voltage suppression, EMI filtering (common mode + differential mode filtering), inrush current suppression / input overvoltage surge suppression / input overcurrent protection / input over- and under-voltage protection / short-circuit protection, RC damping matching network, and OR-ing redundancy, as Figure 3 shown.

[0048] Input spike voltage suppression design: To suppress the input spike voltage signal (maximum 600V / 10μs) and avoid damaging the components of the backend circuit, the commonly adopted solution is to design a transient voltage suppression TVS tube at the front end of the circuit. The design plans to adopt the method of connecting two TVS tubes in series, as Figure 3 shown. TVS1 is used to absorb the forward input spike voltage, and TVS2 is used to absorb the reverse input spike voltage, achieving forward / reverse spike voltage suppression and fully ensuring the reliability design of the product.

[0049] For the EMI filtering part design, special attention should be paid to the shielding treatment of the input power line (especially at the position of the input connector) and the selection of the grounding point for common mode interference suppression to avoid complex electromagnetic interference signals inside the circuit being superimposed on the input power line through the coupling path, reducing the performance of the EMI filter. Designing a high-current and high-noise suppression EMI filter at the front end of the product input is an effective measure to solve the electromagnetic compatibility design problem. The input EMI filter adopts a topological structure of 1-stage common mode filtering + 2-stage differential mode filtering. By reasonably optimizing the parameter design of the filter, a design effect of maximum differential mode noise suppression ≥ 65dB and maximum common mode noise suppression ≥ 40dB can be achieved. The internal principle block diagram is as Figure 4 shown. It is worth noting that during the product design process, the most comprehensive consideration will be given to the EMI electromagnetic compatibility performance design. According to the overall requirements of the system electromagnetic compatibility test, some parameters need to be tested in cooperation with the whole machine, and there is a risk of EMI design rectification.

[0050] (3) Surge suppression design

[0051] Inrush current suppression: Inrush current suppression is achieved by setting an NMOS power switch (Q1) on the IN+ line, as Figure 3As shown, the drain D of the power switch Q1 is connected to the IN+ side, and the source S is connected to the backend circuit. At the moment when the product is powered on and starts up, by controlling the establishment time of the gate-source voltage VGS of the power switch Q1, the characteristic that the on-resistance RDS gradually decreases during the establishment process of the gate-source voltage VGS of the power switch Q1 is fully utilized to suppress the inrush current at the startup moment, and to avoid the excessive inrush current at startup from affecting the stability of the power supply bus voltage. As Figure 5 shown, at the moment when the power is turned on and starts up, the drain-source voltage VDS of the power switch Q1 gradually decreases as the VGS is established, which means that the power switch Q1 gradually transitions from the fully off state to the fully on state. The design of the time constant for the establishment of the gate-source voltage VGS of the power switch Q1 should be appropriate and not too large to avoid the inrush current exceeding the safe operating area of the power switch SOA and damaging the device, as Figure 6 shown. Usually, the time constant for the establishment of the gate-source voltage VGS is between several hundred μs and several tens of ms.

[0052] Input overvoltage surge suppression: Similar to the principle of inrush current suppression at startup, input overvoltage surge suppression is also achieved by setting an NMOS power switch (Q1) on the IN+ line, as Figure 3 shown. The drain D of the power switch Q1 is connected to the IN+ side, and the source S is connected to the backend circuit. When the input voltage VI exceeds the input overvoltage surge suppression clamping set value VOVC (maximum 40V), the gate-source voltage VGS of the power switch Q1 is rapidly reduced, so that the power switch Q1 operates in the linear impedance adjustment state. Relying on the correlation characteristic between the on-resistance RDS and the gate-source voltage VGS of the power switch Q1, the drain-source voltage VDS of the power switch Q1 is adjusted in a timely manner to ensure that the backend output voltage is stabilized at the input overvoltage surge suppression clamping set value VOVC. At this time, the power consumed by the power switch Q1 is VDS×I = (VI - VOVC)×I. It should be ensured that the operating state of the power switch Q1 is within the SOA safe operating area, otherwise it is easy to burn out the device and cause the function to fail.

[0053] Input overcurrent / short-circuit protection: Input overcurrent / short-circuit protection is achieved by setting an overcurrent detection resistor R1 on the IN+ line, as Figure 3 shown. When the voltage drop (I×R1) on the detection resistor R1 exceeds the input overcurrent protection threshold voltage, the gate-source voltage VGS of the power switch Q1 is rapidly reduced, so that the power switch Q1 is in the off state to protect the backend circuit from being damaged due to overcurrent / short-circuit faults. After a certain cycle time, the power switch Q1 is automatically restarted. If the overcurrent / short-circuit fault of the backend circuit has been eliminated at this time, the circuit starts to work normally; if the overcurrent / short-circuit fault of the backend circuit has not been eliminated at this time, the process of restarting the power switch Q1 is terminated, and so on in a cycle until the overcurrent / short-circuit fault of the backend circuit is eliminated.

[0054] The above-mentioned functional design is partially implemented under the unified control and management of a surge suppression controller with ideal diode control function, as Figure 7 shown. By adjusting the grounding capacitance value of the SS port, the starting surge current suppression time constant can be adjusted; by adjusting the grounding capacitance value of the TMR port, the delay cycle time of input overvoltage surge suppression and the restart cycle time of input overvoltage and overcurrent protection can be adjusted; the PROG port is used for setting the input overvoltage surge suppression clamping voltage threshold VOVC; the SNS port is used for input overcurrent protection detection; the input over- and under-voltage protection is realized by external resistor configuration.

[0055] In order to minimize the power loss caused by the 4-way OR-ing redundancy design as much as possible, the design intends to adopt the ideal diode OR-ing design scheme, which can achieve low loss by reducing the on-resistance in the case of large input current, improving the overall efficiency of the product, as Figure 8 shown. The 4-way OR-ing design can be separately integrated into multiple standard 1-inch × 0.5-inch volumes (25.4mm × 12.7mm × 12.7mm, excluding lead-out terminals), realizing the general modular design of the product.

[0056] To improve the overall reliability of the product, the power conversion design part intends to be built using standard and mature isolated DC / DC power modules, as shown in Table 1.

[0057] Table 1 Standard modules used in power conversion design

[0058]

[0059] In order to fully consider the product reliability and power conversion efficiency, the 28V / 14.3A (VO1) power conversion design adopts a standard, mature and stable 140V - 400 wide input voltage range, 28V / 14.3A power output, input BUCK + full-bridge + synchronous rectification topology, optocoupler isolated feedback power converter, with a rated output power of 400W. The functional principle is shown in the following figure. The volume is a standard half brick (58.6mm × 61.6mm × 12.7mm, excluding lead-out terminals), and the typical switching frequency is 200kHz. Under the test conditions of TC = 25°C, input = 270V, and output = 28V / 14.3A, the highest efficiency reaches 92%.

[0060] Considering product reliability and power conversion efficiency, the 5V / 1A (VO2) power conversion design adopts a standard, mature and stable 9V - 36V wide input voltage range, 5V / 2A power output, rated output power of 10W. The functional principle is shown in the following figure. The volume is standard 1 inch × 0.5 inch (25.4mm × 12.7mm × 12.7mm, excluding lead-out terminals), and the typical switching frequency is 310kHz. Under the test conditions of TC = 25°C, input = 28V, and output = 5V / 1A, the highest efficiency reaches 93%.

[0061] In addition, the designed functions of this module also include input undervoltage protection, output overcurrent protection, output short-circuit protection, soft start, and 50V / 1s surge resistance, etc., which can meet the functional design requirements of the product. (3) Considering product reliability and power conversion efficiency, the 5.5V / 10A (VO3), 5.5V / 10A (VO4) power

[0062] conversion design adopts a standard, mature and stable 9V - 36V wide input voltage range, 5.5V / 15A power output, single-ended flyback + active clamp + synchronous rectification topology, optocoupler-isolated feedback power converter, with a maximum output power of 85W. The functional principle is shown in the following figure. The volume is standard 1 / 16 brick (35.3mm × 25.1mm × 12.7mm, excluding lead-out terminals), and the typical switching frequency is 250kHz. Under the test conditions of TC = 25°C, input = 28V, and output = 5.5V / 10A, the highest efficiency reaches 89%.

[0063] In addition, the designed functions of this module also include input undervoltage protection, output overcurrent protection, output short-circuit protection, overtemperature protection, soft start, 50V / 1s surge resistance, etc., which can meet the functional design requirements of the product.

[0064] In addition, the designed functions of this module also include input undervoltage protection, output overcurrent protection, output short-circuit protection, soft start, and 450V / 100ms surge resistance, etc., which can meet the functional design requirements of the product. Adopting the design concept of combining standard, mature and reliable standard power modules with discrete devices, the product design is decomposed into three parts: input EMI electromagnetic compatibility and power supply characteristics design, DC / DC core power conversion design, and power supply status monitoring design, which is beneficial to clarifying the design content, simplifying the process difficulty, and improving product reliability.

[0065] In order to ensure that the reliability design of the product meets the requirements of the whole machine system, combined with the analysis of common failure modes and failure mechanisms of power modules, while selecting components of qualified quality grades for design, the key consideration in product reliability design is to improve the derating level of components.

[0066] After comprehensively considering the integration level, complexity of the product components and the impact of parameter changes among them, the components used in the product design are all derated according to relevant derating requirements. Among them, the important components all meet the derating requirements above level I. The main components inside the product are power devices such as DC / DC power converters. The derating design is shown in Table 2.

[0067] Table 2 Derating Design Table for Key and Important Components

[0068]

[0069] The rated input voltage range of the product is 270V bus (140V - 400V), 28V bus (9V - 36V). The internal design input range meets the relevant requirements, and the maximum output current of the power has a margin design of more than 20%.

[0070] The product has complex function designs, such as EMI filtering, input spike suppression, inrush current suppression at startup, input overvoltage surge suppression, input overcurrent protection, output short - circuit protection, etc. These function and parameter designs are all configured according to the requirements of the technical agreement, and the function tolerance is fully considered to avoid functional design failures when the product is in the critical working state, which affects the reliability of the whole machine.

[0071] For the consideration of simplifying the product design, in the selection of the overall scheme design, all functions of the product are integrated inside three functional units: input EMI electromagnetic compatibility and power supply characteristic design, DC / DC core power conversion design, and power supply status monitoring design, realizing the overall general modular design, greatly reducing the difficulty and complexity of the product design, and improving the overall reliability of the product.

[0072] The tolerance design of the product is mainly achieved through the analysis of the working bias state of internal components and the optimization of device parameter design. The purpose is to ensure that the product has sufficient design margin under various conditions such as within the rated working range, when the working voltage is offset, and when the process model parameters change, so as not to affect the normal working performance of the product.

[0073] The output voltage error signal inside the high - efficiency DC / DC power converter is usually modulated by a reference source (such as AZ431AR - A). Taking the 5V / 1A output as an example, the tolerance analysis simulation model of the output voltage is as Figure 12 shown. Considering the temperature drift characteristics of the parameters of the voltage sampling resistor network components, the Monte Carlo simulation analysis of the circuit output voltage is carried out through SIMetrix software, and the output waveform of VOUT is as Figure 13 shown, and the Monte Carlo histogram is as Figure 14As shown. From the simulation results, it can be seen that in the operating temperature range of -55°C to +100°C, the variation range of the output voltage VOUT is 4.96V to 5.04V. The sampling network resistors of the product output voltage adopt high-precision surface mount resistors with good temperature characteristics, which can further improve the accuracy and temperature drift characteristics of the output voltage.

[0074] Combined with the process structure design scheme of the product, the following conducts a detailed thermal channel design and thermal stress analysis on the key power devices inside the product. The surge-resistant EMI filter with a large power consumption loss (typical efficiency 99%), and the DC / DC power converters (typical efficiencies are 91% (28V / 14.3A), 93% (5V / 1A), 89% (5.5V / 10A) respectively) are fastened to the side plate of the chassis by screws for heat dissipation, and the large-area copper cladding of the interconnected PCB substrate is utilized to increase the heat capacity and further control the steady-state operating case temperature (TC).

[0075] Using the Creo Ansys Simulation professional analysis software for thermal stress simulation, the power consumption and simulation temperature of the main components are shown in Table 8 and Figure 15 as shown. Simulation conditions: The product is in a steady-state operating condition in an open environment, and is calculated at the lowest efficiency of 85% (the actual efficiency is expected to be between 86% and 88%). The simulation temperature is that the fixed case bottom case temperature TC is 100°C, there is no gravity, radiation is not considered, and the heat transfer method mainly considers heat conduction.

[0076] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aviation power board assembly based on a modular redundant architecture, characterized in that: It consists of input protection unit, core power unit, intelligent monitoring unit and redundant power supply system; The input protection unit is composed of a dual TVS series spike suppression module, a three-stage EMI filter and an NMOS surge suppression module; the dual TVS series spike suppression module includes a forward-connected TVS1 and a reverse-connected TVS2, which are connected in parallel at both ends of the input power supply line; the three-stage EMI filter is composed of a 1st-stage common-mode filter and a 2nd-stage differential-mode filter in cascade, the common-mode filter adopts a symmetrical dual-Y capacitor layout, and the differential-mode filter is provided with a magnetic saturation warning circuit; the NMOS surge suppression module includes a dynamic gate voltage control circuit, and the gate voltage establishment time is controlled to be 500μs-50ms through an adjustable time constant circuit; The core power unit includes a half-brick 270V to 28V module, a 28V to 5V module and a dual-channel 1 / 16 brick 28V to 5.5V module; the half-brick 270V to 28V module adopts a BUCK pre-regulator stage and a full-bridge isolation cascade topology, and the input voltage range is 140-400V; the 28V to 5V module adopts a single-ended flyback topology with a built-in synchronous rectifier MOS tube; the 28V to 5.5V module adopts an active clamp flyback topology and includes a body diode reverse recovery suppression circuit; The intelligent monitoring unit comprises a four-channel voltage state comparator, an optocoupler isolation digital communication module and a power-off maintenance circuit; the voltage state comparator is provided with four independent detection channels, each channel comprising a window comparison circuit and a hysteresis comparison circuit; The optical coupler isolation digital communication module supports TTL / LVTTL level conversion, and the transmission delay is less than 100ns; the power-off maintenance circuit adopts a hybrid energy storage structure of supercapacitor and lithium-ion battery; The redundant power supply system consists of a four-way OR-ing topology, including a 28V maintenance power supply, a 270V external power supply, and four inputs of onboard 28V power supplies I and II. Each OR-ing branch is equipped with an ideal diode controller with an on-resistance of less than 5mΩ and a built-in fault isolation switch. Each branch is equipped with a Hall current sensor with a sampling accuracy of ±1%.

2. The aviation power board assembly based on modular redundant architecture according to claim 1, characterized in that: It also includes a three-dimensional heat dissipation structure, which includes a gold-plated copper substrate, a thermal grease filling layer and corrugated heat dissipation fins; the gold-plated copper substrate is 0.8mm thick and is directly connected to the bottom of the power module by screws; the thermal conductivity of the thermal grease filling layer is ≥5W / m·K, and the coverage area accounts for 85% of the surface area of ​​the PCB substrate; the corrugated heat dissipation fins are 8mm high and 2mm apart and are arranged on the PCB base.

3. The aviation power board assembly based on modular redundant architecture as claimed in claim 2, characterized in that: The PCB substrate adopts a six-layer stacking structure, and the layer sequence is signal layer-power layer-ground layer-power layer-signal layer-protective layer; the key signal line adopts a stripline layout, and the characteristic impedance is controlled at 50Ω±5%; the power routing width is ≥3mm, and the copper coating thickness is 2oz.

4. The aviation power board assembly based on modular redundant architecture according to claim 1, characterized in that: It also includes a state monitoring system, which includes a voltage ripple spectrum analysis module, a distributed thermistor array and a load transient response test circuit; the spectrum analysis module has a sampling bandwidth of 20MHz and an FFT analysis point number of 1024; the thermistor array includes 8 PT1000 sensors arranged on the surface of the power module; the load transient response test circuit can generate a step load of 1A / μs.

5. The aviation power board assembly based on modular redundant architecture according to claim 1, characterized in that: The ideal diode controller includes a comparator module, a drive circuit and a fault feedback loop; the comparator module monitors the input voltage difference in real time, and activates the fast switching circuit when the voltage difference exceeds 5mV. The drive circuit uses charge pump technology to provide negative bias to ensure that the MOS tube is completely turned off; the fault feedback loop transmits the status signal to the monitoring unit through a digital isolator.

6. The aviation power board assembly based on modular redundant architecture according to claim 1, characterized in that: The active clamp flyback topology forms an energy recovery branch by connecting a clamp capacitor in series with a MOS tube, and drives a signal delay compensation circuit through a synchronous rectifier tube. The compensation time is adjustable from 50 to 150 ns, and the leakage inductance energy absorption circuit is composed of a transient voltage suppressor and an RC buffer network in parallel.

7. The aviation power board assembly based on modular redundant architecture according to claim 1, characterized in that: The dynamic gate voltage control circuit includes a programmable timer chip, an SOA protection module and a temperature compensation circuit, wherein the programmable timer chip adjusts the time constant through an external capacitor; the SOA protection module collects the drain-source voltage and the drain current in real time, and forces shutdown when the operating point exceeds the SOA curve; and the temperature compensation circuit adjusts the gate drive voltage slope according to the junction temperature.

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