Double-three-phase fractional-slot winding carbon fiber reinforced high-speed generator and design method

Abstract

The invention relates to the technical field of high-speed generators, and discloses a double-three-phase fractional-slot winding carbon fiber reinforced high-speed generator and a design method.The double-three-phase fractional-slot winding carbon fiber reinforced high-speed generator comprises a permanent magnet synchronous motor, the permanent magnet synchronous motor adopts a double-three-phase winding surface-mounted topology and fractional-slot distribution winding, and a carbon fiber bundle is arranged on the surface of a rotor; the stator winding adopts a split transposition structure and is internally provided with an oil duct; and the controllable rectification controller adopts a three-phase two-level main power conversion topology and comprises a control circuit of a dual-digital signal processor redundancy architecture, a driving circuit of a multi-level driving architecture and a three-phase full-bridge silicon carbide main power circuit adaptive to a high-voltage multi-level topology. By adopting the dual three-phase fractional slot winding surface-mounted permanent magnet synchronous motor topology and cooperating with the split transposition winding structure, the winding circulation loss is reduced, the fault-tolerant capability is improved, and the rotor is bundled and reinforced by carbon fiber wires to counteract the high-speed rotation centrifugal force.

Description

Technical Field

[0001] This invention relates to the field of high-speed generator technology, specifically to a high-speed generator with dual three-phase fractional slot windings reinforced with carbon fiber and its design method. Background Technology

[0002] High-speed generators are power generation devices with a rated speed significantly higher than that of traditional motors. With their high power density, small size, and fast response speed, they are widely used in fields with stringent requirements for lightweight and high efficiency, such as aerospace, new energy vehicles, and distributed power generation. These generators shorten the electromagnetic conversion path by increasing the rotor speed, and can output higher power in the same volume. They are one of the core devices for achieving miniaturization and high efficiency of power systems. However, existing technologies for high-speed generators have certain shortcomings. When rotating at high speed, the rotor is subjected to huge centrifugal force. Surface-mounted permanent magnets are prone to falling off or breaking due to excessive tensile stress. Traditional metal sheaths are difficult to balance strength and high-speed performance. Furthermore, multi-strand parallel windings generate significant circulating losses due to uneven leakage magnetic field distribution. Combined with other losses, this leads to excessively high winding temperature rise, and traditional cooling methods are difficult to meet the requirements. To address the shortcomings of existing technologies, this invention proposes a high-speed generator with dual three-phase fractional slot windings and carbon fiber reinforcement. Summary of the Invention

[0003] The purpose of this invention is to provide a high-speed generator with carbon fiber reinforcement and a design method for a dual three-phase fractional slot winding, in order to solve the problems in the prior art where surface-mounted permanent magnets in high-speed generators are prone to falling off or breaking due to excessive tensile stress, resulting in significant circulating losses and unsatisfactory cooling methods.

[0004] The objective of this invention can be achieved through the following technical solutions: A high-speed generator with dual three-phase fractional-slot windings and carbon fiber reinforcement includes: The permanent magnet synchronous motor adopts a double three-phase winding surface-mount topology and fractional slot distributed winding. The rotor surface is provided with carbon fiber binding. The stator winding adopts a strand transposition structure and has oil channels inside. A controllable rectifier controller, wherein the controllable rectifier controller adopts a three-phase two-level main power conversion topology, including a control circuit with a dual digital signal processor redundant architecture, a drive circuit with a multi-level drive architecture, and a three-phase full-bridge silicon carbide main power circuit adapted to the high-voltage multi-level topology. Support capacitors, including customized film capacitors and integrated multi-layer low-inductance busbars; The position detection circuit includes a decoding chip, and the peripheral interface of the decoding chip includes an excitation conditioning circuit and a sine and cosine signal filtering circuit.

[0005] Preferably, the strand transposition winding divides the 21 parallel strands into 3 groups, with each group wound around the root, middle and top of three adjacent teeth respectively.

[0006] Preferably, the controllable rectifier controller includes a control circuit, a drive circuit, and a three-phase full-bridge silicon carbide main power circuit; The control circuit is powered by two airborne low-voltage DC power supplies connected in parallel after being regulated by two wide-voltage input isolation power supply modules. After passing through the auxiliary power supply circuit, it powers the resolver decoding circuit, sampling conditioning circuit, logic protection circuit, communication interface circuit and digital control circuit respectively. The driving circuit adopts a multi-level driving architecture; The three-phase full-bridge silicon carbide main power circuit uses a silicon carbide power module adapted to a high-voltage multi-level topology.

[0007] Preferably, each bridge arm of the three-phase full-bridge silicon carbide main power circuit is equipped with a distributed buffer capacitor structure.

[0008] Preferably, the peripheral interface circuit of the decoding chip includes an excitation conditioning circuit and a sine and cosine signal filtering circuit; The excitation conditioning circuit includes a dual-power amplifier circuit, which amplifies the AC signal output by the decoding chip through a complementary push-pull circuit to provide excitation voltage. The sine and cosine signal filtering circuit is used to adjust the input gain, suppress common-mode interference, filter noise, and detect open circuit faults.

[0009] This invention also provides a design method for a high-speed generator with dual three-phase fractional slot windings reinforced with carbon fiber, comprising: The parameters of the high-speed generator were set using a multi-objective optimization method, and the capacitance value and ripple current of the supporting capacitor were obtained. The optimization software and optimization script are combined. The optimization script calls the motor design software, and the motor is optimized by the genetic algorithm in the multi-objective optimization software. When the motor is at its rated speed, finite element software is used to evaluate each candidate parameter in detail; Based on the evaluation results, the parameters of the high-speed generator are further refined using a fast convergence algorithm, and finally selected.

[0010] Preferably, the capacitance value of the supporting capacitor is determined by the formula: ; ;

[0011] in, Peak power, For switching frequency, The bus voltage is used as the reference. Based on the calculated maximum and minimum capacitance values, and considering the reliability of the airborne equipment, a suitable capacitor is selected.

[0012] Preferably, the ripple current of the supporting capacitor is expressed by the formula: ; in, This represents the effective value of the bus capacitor ripple current. This is the effective value of the motor phase current. In order to adjust the system, The power factor.

[0013] The beneficial effects of this invention are: 1. This invention employs a dual three-phase fractional-slot surface-mount permanent magnet synchronous motor topology, combined with a stranded transposition winding structure, to reduce winding circulating current losses and improve fault tolerance. The rotor is reinforced with carbon fiber bundles to counteract high-speed centrifugal force and protect the permanent magnets from falling off. An in-slot oil cooling system enhances heat dissipation. The controllable rectifier controller uses a dual-redundant architecture, silicon carbide power modules, and multi-level drive circuits. Customized thin-film capacitors and stacked busbars reduce parasitic inductance. Based on a decoding chip and peripheral conditioning filter circuits, detection accuracy is improved. This achieves the effects of increasing motor torque density and power density, reducing losses and temperature rise, and enabling the motor to operate stably at rated peak values. It solves problems such as insufficient rotor strength, high winding losses, difficult heat dissipation, high parasitic inductance of the power conversion system, low position detection accuracy, and insufficient reliability of high-speed generators.

[0014] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a multi-objective optimization design flowchart of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and a design method thereof, according to the present invention.

[0017] Figure 2 This is a block diagram of the multi-objective optimization design program for a high-speed generator with carbon fiber reinforcement and a design method for a dual three-phase fractional slot winding, as described in this invention.

[0018] Figure 3 This diagram shows the multi-objective optimization design results of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, as well as its design method, according to the present invention.

[0019] Figure 4 This is a schematic diagram of the dual three-phase controllable rectifier controller scheme of the present invention, which is a dual three-phase fractional slot winding carbon fiber reinforced high-speed generator and its design method.

[0020] Figure 5 This is a schematic diagram of the strand transposition winding structure of a high-speed generator with carbon fiber reinforcement and a design method for a double three-phase fractional slot winding according to the present invention.

[0021] Figure 6 This is a schematic diagram of a customized thin-film capacitor and integrated stacked busbar structure for a high-speed generator with carbon fiber reinforcement and a design method for a dual three-phase fractional slot winding according to the present invention.

[0022] Figure 7 This is a circuit diagram of the excitation signal conditioning circuit for a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0023] Figure 8 This is a circuit diagram of a sine and cosine signal filtering circuit for a high-speed generator with carbon fiber reinforcement and a design method for a dual three-phase fractional slot winding, as described in this invention.

[0024] Figure 9 This is a phase current sampling circuit diagram for a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0025] Figure 10 This is a bus current sampling circuit diagram for a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0026] Figure 11 This is a bus voltage sampling circuit diagram for a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0027] Figure 12 This is a temperature sampling circuit diagram of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0028] Figure 13 This is a schematic diagram of the oil passage structure of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and its design method, according to the present invention.

[0029] Figure 14 This is a schematic diagram of the carbon fiber bundling structure for a high-speed generator with carbon fiber reinforcement using a dual three-phase fractional slot winding and a design method according to the present invention.

[0030] Figure 15 This is a schematic diagram of the front cover structure of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding according to the present invention.

[0031] Figure 16This is a schematic diagram of the electromagnet structure of a high-speed generator with carbon fiber reinforcement and a dual three-phase fractional slot winding, and the design method thereof, according to the present invention.

[0032] Figure 17 This is a schematic diagram of the connector cover structure of a high-speed generator with carbon fiber reinforcement and a design method for a dual three-phase fractional slot winding according to the present invention.

[0033] Figure 18 This is a schematic diagram of channel one in the architecture of a dual three-phase controllable rectifier controller scheme of a dual three-phase fractional slot winding carbon fiber reinforced high-speed generator and its design method according to the present invention. The components include: 1. Cross-head pan screw (one type); 2. Cross-head pan screw (two types); 3. Connector cover; 4. Wire thread insert (one type); 5. Front end cover; 6. Front bearing sleeve; 7. Cross-head pan screw (three types); 8. Cross-head countersunk screw (one type); 9. Deep groove ball bearing; 10. Shaft; 11. Magnet; 12. Extension shaft; 13. Flat key; 14. Stator lamination; 15. High-temperature wire (one type); 16. High-temperature wire (two types); 17. High-temperature wire (three types); 18. Housing; 19. Wire thread insert (two types); 20. Housing bushing; 21. Bearing cover; 22. Cross-head countersunk screw (two types); 23. Hexagonal bushing; 24. Flange; 25. Cross-head countersunk screw... 26. Head screw 3; 27. Support column; 28. Yoke; 29. ​​Electromagnet; 30. Slotted cylindrical head screw; 31. Connector 1; 32. Connector 2; 33. Enamelled wire; 34. Cross-head countersunk screw 4; 35. Cross-head countersunk screw 5; 36. Resolver cover; 37. Socket head screw; 38. Small washer; 39. Hexagonal locknut; 40. Resolver frame; 41. Shielded twisted pair cable; 42. Slotted tapered set screw; 43. Brake pad; 44. Spring; 45. Stop block; 46. Wire guide cover; 47. Oil passage; 48. Carbon fiber bundle; 49. Permanent magnet; 50. Winding. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1-18As shown, this invention relates to a high-speed generator with dual three-phase fractional slot windings and carbon fiber reinforcement, and its design method. It utilizes a combination of optimization software ModeFrontier and MATLAB scripts, calling the motor design software Motor-CAD via the scripts, and optimizing the motor using the MOGA-II genetic algorithm within ModeFrontier. When the motor is at its rated speed, finite element analysis software is used to evaluate each candidate parameter in detail. The first stage of optimization employs the Design of Experiment (DoE) method. Subsequently, based on the results obtained in the first stage, a Pareto-based algorithm with fast convergence is used for further refinement. In this project, the DoE of random sequences provides 30 initial population sizes, a crossover probability of 0.8, and a DNA mutation rate of 0.05, providing detailed evaluations of a total of 900 candidate designs. The optimization objectives are torque density and efficiency, such as Figure 3 As shown, the horizontal axis represents torque density, with values ​​ranging from 18 to 23, reflecting the overall performance of the motor in terms of lightweight design and high torque under different parameter combinations. The vertical axis represents motor efficiency, reflecting the energy conversion efficiency of the motor under different parameter combinations. The scheme is optimized based on the overall system efficiency and weight requirements. The specific parameters are as follows:

[0036] A permanent magnet synchronous motor with a surface-mount structure is selected because it has a small direct-axis inductance, low armature reaction, and good torque-current linearity. At the same time, since the permeability of the permanent magnet material is basically equal to that of air, the magnetic reluctance of the surface-mount d-axis and q-axis magnetic circuits is equal, and therefore the d-axis and q-axis inductances are equal. It is a salient-pole motor with a magnetic reluctance torque component that is basically zero. Insertion-type rotors have asymmetrical d-axis and q-axis magnetic circuits, making them salient-pole motors with a small reluctance torque component. Surface-type rotor structures have a smaller d-axis inductance, weaker armature reaction, and stronger overload capacity. Using a Hale-Becker array can further increase the air gap magnetic flux density and torque density. However, the near-1 salient-pole ratio results in poor field weakening capability, making them suitable for applications requiring high torque density but not field weakening, such as aircraft generator systems. Regarding the selection of the number of pole pairs for permanent magnet synchronous motors, from the perspective of torque density, the higher the number of pole pairs within a reasonable range, the better. However, an excessively high number of pole pairs will increase the motor's operating frequency. Considering the controller's switching frequency and the motor's AC losses, it should not be too high. After comprehensive consideration, a 3-pole pair scheme was finally selected.

[0037] In recent years, fractional-slot distributed winding permanent magnet synchronous motors have received much attention. Compared with short-pitch distributed windings, full-pitch distributed windings have a larger winding factor and higher torque or power density. Therefore, a 6-pole rotor scheme is adopted. The number of stator slots with excellent overall performance can be selected as 36 / 54 / 72. If the number of slots is too low, the contact area between the winding and the iron core is smaller, which limits the heat dissipation effect. If the number of slots is too high, the pure copper slot fill factor of the motor will decrease and the difficulty of production will increase. Considering the winding factor, 36 slots were finally selected. When the motor rotates at high speed, the centrifugal force of the rotor is very large. When the linear velocity reaches 200m / s or more, conventional laminated rotors are difficult to withstand the centrifugal force generated by high-speed rotation. Special high-strength laminated or solid rotors are required. For surface-mounted structure motors, the rotor strength problem is even more prominent because the sintered permanent magnet material cannot withstand the tensile stress generated by high-speed rotation and there is a risk of falling off and rubbing against the rotor. Protective measures must be taken for the permanent magnet. This project uses carbon fiber bundling to improve rotor strength. The carbon fiber wrapped around the magnet surface can apply prestress to counteract the centrifugal force generated by high-speed rotation and protect the magnet from damage. Winding copper losses can be categorized into DC copper losses, eddy current losses, and circulating current losses. DC copper losses are caused by the DC resistance of the winding, which gradually increases with temperature. To address the eddy current loss problem caused by uneven conductor current density distribution in motors, multi-strand wires are typically wound in parallel. However, due to the influence of leakage flux in the slots, the induced electromotive force distribution of the multi-strand wires is uneven, leading to circulating currents between the strands. This results in severe circulating current losses at high frequencies, causing excessive winding temperature rise and thus affecting motor efficiency. By theoretically analyzing the internal magnetic field of a high electromagnetic load motor, the mechanism of circulating current generation in the stator winding was revealed, and an equivalent transposition configuration of the stator winding was proposed to effectively suppress the circulating current in the winding. Taking 21 strands of wire wound in parallel per turn as an example, the transposition is explained as follows: Figure 5 As shown, the 21 parallel strands are divided into three groups (7+7+7). Taking phase B as an example, each group of parallel strands is wound around the root, middle, and tip of three adjacent teeth. This winding method ensures that the back potential difference between each group of strands is very small, thereby reducing the back potential difference between strands within a group and suppressing circulating current. Compared with the ideal winding structure, the advantage is that each strand within a group does not need a fixed position, significantly reducing the difficulty of the winding process.

[0038] To increase the power density of permanent magnet motors, electromagnetic load and rotor speed are usually increased, but this also leads to higher losses and heat. When the heat generated inside the armature winding is difficult to extract, traditional water jacket cooling systems cannot solve the problem of high temperature rise of motors under high power density. Therefore, this application adopts in-slot oil cooling to improve the heat dissipation effect of the motor. By reserving oil channels inside the two sets of windings to increase the heat dissipation area, the operating current density of the motor can be increased.

[0039] As a core component of digital controllers, the main control architecture of the controllable rectifier controller is the foundation for implementing high-performance control. Therefore, the selection of the main control chip is particularly critical. Digital signal processors (DSPs) are high-speed, high-precision microprocessors based on the RISC instruction set, capable of implementing complex control algorithms. They are well-suited for applications with high data transmission rates and large data processing volumes. Compared to other main control chips, their significant advantages are as follows: The Harvard bus architecture was improved by adopting a dual-bus structure consisting of a data bus and an address bus. Furthermore, by separating data and address into two separate spaces, instruction read and data read operations can be completed simultaneously, significantly reducing computation time and enhancing real-time performance. One or more multiplication and addition operations can be completed within one instruction cycle, making it more suitable for complex control algorithms and high-order filtering operations; It provides a variety of peripheral interfaces, including serial I / O interfaces, parallel I / O interfaces, and special function I / O interfaces, to complete special data control or processing, thereby improving the system's operating speed and reducing costs; The various performance and control algorithms of digital signal processors can be implemented through software programming, and they can also execute code generated by MATLAB simulation programs.

[0040] The TMS320F28335 digital signal processor is currently the mainstream choice in the field of generator control. Its advantages can be summarized as follows: its 150Hz main frequency ensures its powerful processing and computing capabilities, which can meet the large computational demands of multi-task control algorithms in motor controllers; its external expansion interface facilitates the implementation of external memory and other peripherals, providing great design flexibility and laying the foundation for the implementation of advanced high-performance control algorithms in the motor controller; at the same time, its rich on-chip peripherals, such as up to 16 PWM output channels, 16 ADC sampling channels, and ample I / O interfaces, as well as dual CAN communication interfaces, are all essential hardware requirements for the main control circuit.

[0041] Based on the above analysis, the main control unit of the dual three-phase controllable rectifier controller is designed using a TMS320F28335 digital signal processor. The sampling and conditioning circuit collects key signals from the drive circuit, main power circuit, and motor to the digital signal processor. Based on the control commands received from the CAN communication circuit and network communication interface circuit, it completes closed-loop control according to a predetermined control strategy. Simultaneously, it sends corresponding switching signals to the drive circuit, thereby forcing the silicon carbide power module to perform corresponding actions. It is worth noting that the dual three-phase high-voltage silicon carbide controllable rectifier controller is designed to use a dual digital signal processor architecture to ensure the independence, reliability, and speed of the dual three-phase controllable rectifier system. The main digital signal processor and the auxiliary digital signal processor need to communicate via SPI for some key information to ensure control synchronization and reliability after a fault, such as the d-axis and q-axis currents. Silicon carbide (SiC) power devices offer numerous technological advantages over silicon-based devices: their wide bandgap characteristics enhance stability, providing excellent high-temperature resistance, high-voltage resistance, and radiation resistance, thereby significantly increasing power density and facilitating system heat dissipation and miniaturization; their high breakdown electric field strength helps expand the power range of SiC devices, reduces on-resistance, and enables high-voltage resistance and low energy consumption, facilitating device thinning while increasing system driving force; their high saturated electron drift velocity results in lower resistance, significantly reducing energy loss, simplifying peripheral passive components, and greatly increasing switching frequency while improving overall system efficiency. Therefore, in order to meet the wide input voltage range of 900±150VDC, while improving system efficiency and reducing system weight, the dual three-phase high-voltage silicon carbide controllable rectifier controller is designed with a 1700V silicon carbide power module as the main power unit.

[0042] If the dual three-phase controlled rectifier topology handles all the power, then based on the maximum power divided by the load condition, each phase winding needs to carry an effective current of 300A. Considering the maximum bus operating voltage of 1050V, the silicon carbide power devices should at least meet a bus operating voltage of 1700V and a high-temperature effective current of 500A. Based on these two specifications, the power devices and drive circuit of this dual three-phase high-voltage silicon carbide controlled rectifier controller have the following two feasible solutions: The ASC600N1700HPD silicon carbide power module is used as the driving power device. The maximum bus operating voltage of this power module can reach 1700V, the maximum operating junction temperature is 175℃, and the maximum output current can reach 600A, all of which meet the requirements of the dual three-phase high-voltage silicon carbide controlled rectifier controller. In addition, its stray inductance is less than 10nH, which can effectively improve the switching characteristics of the power module, reduce voltage overshoot and oscillation, and improve electromagnetic interference. At the same time, its unique pin-fin heat dissipation structure can effectively increase the heat exchange area and heat exchange efficiency between the power module and the cooling medium, thereby achieving excellent heat dissipation performance.

[0043] For the silicon carbide power module in this HPD package, it can be driven by the commercially available and mature SIC-HPDLPS driver board. The SIC-HPDLPS is a plug-and-play digital driver board based on the NXP highly integrated MC33GD3100 chip. The module has a maximum gate output current of ±15A, active Miller clamping function and fast desaturation detection protection function with a detection time of less than 2us. It supports two-stage shutdown and soft shutdown, primary and secondary side power supply undervoltage and overvoltage protection, NTC detection and VDC detection, and has an isolated SPI intelligent digital interface. The parameters are flexibly configured and the status monitoring is complete. Its wide operating temperature range of -40℃ to 125℃ meets the safety requirements of automotive grade.

[0044] The ASC600N1700DCS12 silicon carbide power module is used as the driving power device. The maximum bus operating voltage of this power module can reach 1700V, the maximum operating junction temperature is 175℃, and the maximum output current can reach 600A, all of which meet the requirements of the dual three-phase high-voltage silicon carbide controlled rectifier controller. In addition, its stray inductance is less than 7nH, which can also effectively improve the switching characteristics of the power module, reduce voltage overshoot and oscillation, and improve electromagnetic interference.

[0045] Unlike the ASC600N1700HPD silicon carbide power module, the ASC600N1700DCS12 packaged silicon carbide power module is an automotive-grade silicon carbide power module based on a series of technologies such as silver sintering process, parallel water channel design, flexible half-bridge structure, and high-durability packaging. It can achieve higher junction temperature and better extreme junction temperature cycling, which enables high-speed power generation systems to improve power density and higher power output capabilities.

[0046] The corresponding gate driver and drive power supply can be designed using UCC21750-Q1 and UCC14241-Q1, respectively. UCC21750-Q1 is an electrically isolated single-channel gate driver for silicon carbide metal-oxide-semiconductor field-effect transistors with a DC operating voltage of up to 2121V, featuring advanced protection functions, excellent dynamic performance and robustness.

[0047] The UCC21750-Q1 features peak pull-up and pull-down currents up to ±10A, input-side isolation from output-side via SiO2 capacitors, supports operating voltages up to 1.5kVRMS, surge immunity of 12.8kVPK, isolation layer lifetime exceeding 40 years, and provides low inter-device skew and common-mode noise immunity (CMTI) greater than 150V / ns.

[0048] The UCC14241-Q1 is an automotive-grade, high-isolation DC / DC power module designed to power SiC gate drivers. It integrates a transformer and DC / DC controller with a proprietary architecture, enabling high efficiency and ultra-low emitt voltage. High-precision output voltage provides better channel enhancement, resulting in higher system efficiency without overstressing the gates of power devices.

[0049] The UCC14241-Q1 can efficiently provide up to 2W of isolated output power. This module requires very few external components and features on-chip device protection, providing additional features such as input undervoltage lockout, overvoltage lockout, output voltage power supply normalization comparator, thermal shutdown, soft-start timeout, adjustable isolated positive and negative output voltages, enable pin, and open-drain output power supply normalization pin.

[0050] Compared to electrolytic capacitors, film capacitors have the following advantages: film capacitors have better temperature and frequency characteristics than electrolytic capacitors; film capacitors are non-polarized and can withstand reverse voltage; they have high rated voltage, do not require series and balancing resistors; they adopt a dry design, eliminating electrolyte leakage and acid contamination problems; they have lower ESR; they have strong ripple current resistance; they have a non-inductive design; they have low ESL; and they have a long service life, with virtually no lifespan limit unless damaged.

[0051] Because silicon carbide power devices are used, the system operates at a high switching frequency, resulting in a large change in current per unit time. Therefore, it is highly sensitive to the parasitic inductance parameters of the system's power circuit. This project proposes to use customized thin-film capacitors and integrated multilayer busbars, which can significantly reduce the parasitic inductance of the power circuit. This will reduce the voltage stress generated by the silicon carbide power devices during high-frequency, high-current interruption under peak power conditions, thereby improving system reliability.

[0052] Capacity calculation: According to the formula, the maximum and minimum values ​​of the bus capacitance are: ; ; in, Peak power, For switching frequency, For the bus voltage, substitute the value. , , The calculation yields: , For reliability considerations of the airborne equipment, the maximum value is selected as the design value of the bus capacitor, that is, the final selected capacitor value is: .

[0053] Ripple current calculation: The ripple current on the capacitor is calculated as follows: ; in, This represents the effective value of the bus capacitor ripple current. This is the effective value of the motor phase current. In order to adjust the system, The power factor.

[0054] Select , The table below shows the variation of ripple current with modulation degree. It can be seen that when... At that time, the maximum ripple current is .

[0055] Table of ripple current variation with modulation degree

[0056] Based on controller development experience, the rated voltage of the bus capacitor is generally 1.2-1.5 times the bus voltage. In this application, the highest bus voltage is 1050V, and the rated voltage of the bus capacitor can be selected as 1500V.

[0057] Motor position signal detection typically utilizes Hall effect position sensors, photoelectric encoders, and rotary transformers. While Hall effect position sensors are inexpensive, their resolution is relatively low, resulting in poor system control accuracy. Furthermore, prolonged overheating of the Hall element can weaken its magnetism, affecting its lifespan. Photoelectric encoders offer higher resolution but have lower protection levels and vibration resistance. Brushless rotary transformers, with their separate stator and rotor, resemble motor structures, offering high protection levels, strong resistance to harsh environments, and a long lifespan. Combined with digital decoding chips, they can convert the rotary transformer's output analog signals into digital signals with high decoding accuracy. The design utilizes the AU6802N1 decoding chip. The decoding circuit provides excitation voltage to the resolver and decodes the rotor position information contained in the sine and cosine signals into digital outputs, which can be output serially or in parallel. The resolver's excitation winding requires a high-quality sine wave excitation signal. Furthermore, the sine and cosine signals output by the resolver must also meet the decoding chip's requirements for input signal amplitude and phase. Therefore, the AU6802N1 requires external interface circuitry, including excitation conditioning circuitry and sine and cosine signal filtering circuitry. The resolver requires a 7V 10kHz excitation signal, while the RSO / COM output signal of the AU6802N1 chip is based on 2.5V and has an interpolated sine wave with a peak-to-peak value of 2V. Its output power is very small and cannot directly drive the resolver's excitation winding; therefore, an excitation conditioning circuit is needed. Excitation conditioning circuits can be either dual-supply or single-supply. This design proposes a dual-supply Booster power amplifier circuit. The output of the decoding chip's RSO / COM is converted to an AC signal via a DC blocking capacitor C358, which is then amplified by a complementary push-pull circuit composed of a subsequent operational amplifier and NPN and PNP transistors. Simultaneously, a phase compensation capacitor C369 ensures system stability, and the output excitation voltage amplitude is adjusted via R422. The sine and cosine signals output by a resolver contain many interference signals, therefore they must be processed by a conditioning filter circuit. The functions of the conditioning filter circuit include adjusting the circuit input gain, suppressing common-mode interference, filtering external noise interference, and detecting circuit open-circuit faults. A sine and cosine signal filtering circuit is as follows: Figure 8 As shown, the output signal filtering and conditioning circuit of the resolver cosine is the same as that of the sine.

[0058] Please see Figure 13-17As shown, the high-speed motor includes a cross-slot pan head screw 1, which connects the front cover 5 and the housing 18. A cross-slot pan head screw 2 connects the cross-slot pan head screw 3. Connector covers 3 are connected inside connectors 1 and 2. Wire thread inserts 4 are installed in the threaded holes of the housing 18 and the front cover 5 to enhance the connection strength. A front bearing sleeve 6 is fixed inside the front cover 5 to mate with a deep groove ball bearing 9. The deep groove ball bearing 9 is sleeved at both ends of the rotating shaft 10, which is the central rotating shaft. Magnets 11 and permanent magnets 49 are mounted on the surface of the shaft. Carbon fiber is provided on the outside of the permanent magnets 49. The Vizab 48, the extension shaft 12 is connected to the rotating shaft 10 via a flat key 13 and extends to the end of the motor, the stator laminations 14 are stacked to form a stator core, the inner toothed grooves are wound with a winding 50, the winding 50 adopts a strand transposition structure and has an internal oil passage 47, high temperature wire 15, high temperature wire 216, high temperature wire 317 are used to connect the lead wires of the winding 50, connector 1 30 and connector 2 31; the housing 18 encloses the stator laminations 14 and the rotor assembly, the end is connected to the front cover 5 via a steel wire thread sleeve 2 19, the inner side is installed with a housing bushing 20, the bearing cover 21 is set at the other end of the rotating shaft 10, and is connected by a cross-slot countersunk screw 18. Fixed to the end of the housing 18, the hexagonal bushing 23 is used for auxiliary positioning. The flange 24 is installed on one side of the bearing cover 21 and is fixed by the cross-head countersunk screw 25. The cross-head countersunk screw 22 is used to connect to the flange 24. The support column 26 supports the yoke 27. The electromagnet 28 is fixed on the yoke 27 by the slotted cylindrical head screw 29. The enameled wire 32 is the conductive material of the winding 50 and is wound in the tooth groove of the stator lamination 14. The cross-head countersunk screw 33 is used to connect to the resolver frame 40. The cross-head countersunk screw 34 is used to fix the flange 24. The resolver cover 35 is fixed by the internal hexagonal cylindrical head screw 36. A resolver 39 is covered on the housing 18. A hexagonal head screw 36 secures the resolver cover 35 to the resolver frame 40. A small washer 37 is fitted onto the screw to increase the bearing area. A hexagonal lock nut 38 is used to fix the housing 18 to other components. The resolver 39 is connected to the resolver frame 40. One end of the shielded twisted pair cable 41 is connected to the resolver 39, and the other end passes through the cable guide plate 46 to connect to the controller. A slotted tapered set screw 42 is used to fix the internal components of the flange 24. The brake pad 43 cooperates with the stop block 45 through the spring 44 to achieve motor braking. The cable guide plate 46 is fixed to the side of the housing 18 with screws to seal the wire through holes.

[0059] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A dual three-phase fractional-slot winding carbon fiber reinforced high speed generator characterized by, It comprises: A permanent magnet synchronous motor with double three-phase winding surface-mounted topology and fractional slot distributed winding, the rotor surface is provided with carbon fiber bundles, the stator winding adopts a sub-stock transposition structure and is internally provided with an oil channel; A controllable rectifier controller with a three-phase two-level main power conversion topology, including a control circuit with a dual digital signal processor redundant architecture, a drive circuit with a multi-level drive architecture, and a three-phase full-bridge silicon carbide main power circuit adapted to a high-voltage multi-level topology; A support capacitor including a customized thin film capacitor and integrated multi-layer low inductance busbars; A position detection circuit including a decoding chip, the peripheral interface of the decoding chip including an excitation conditioning circuit and a sine and cosine signal filtering circuit.

2. A dual three-phase fractional-slot winding carbon fiber reinforced high speed generator as claimed in claim 1, characterized in that, The sub-stock transposition winding divides 21 parallel winding strands into three groups, each group being wound around the tooth root, middle and top of adjacent three teeth.

3. A dual three-phase fractional-slot winding carbon fiber reinforced high speed generator as claimed in claim 1, characterized in that, The controllable rectifier controller includes a control circuit, a drive circuit and a three-phase full-bridge silicon carbide main power circuit; The control circuit is powered in parallel by two on-board low-voltage DC power supplies after voltage stabilization by two wide-voltage input isolation power supply modules, and powers the resolver decoding circuit, sampling conditioning circuit, logic protection circuit, communication interface circuit and digital control circuit after the auxiliary power supply circuit; The drive circuit adopts a multi-level drive architecture; The three-phase full-bridge silicon carbide main power circuit adopts a silicon carbide power module adapted to a high-voltage multi-level topology.

4. A dual three-phase fractional-slot winding carbon fiber reinforced high speed electrical generator as claimed in claim 3, characterized in that, Each bridge arm of the three-phase full-bridge silicon carbide main power circuit is provided with a distributed buffer capacitor structure.

5. A dual three-phase fractional-slot winding carbon fiber reinforced high speed electrical generator as claimed in claim 1, characterized in that, The decoding chip peripheral interface circuit includes an excitation conditioning circuit and a sine and cosine signal filtering circuit; The excitation conditioning circuit includes a dual power power amplifier circuit for amplifying the alternating current signal output by the decoding chip through a complementary push-pull circuit to provide excitation voltage; The sine and cosine signal filtering circuit is used to adjust the input gain, suppress common mode interference, filter noise and detect broken wire faults.

6. A design method of a dual three-phase fractional-slot winding carbon fiber reinforced high-speed generator, for a dual three-phase fractional-slot winding carbon fiber reinforced high-speed generator, characterized in that, It comprises: Setting various parameters of the high-speed generator through a multi-objective optimization method to obtain the capacitance value and ripple current of the support capacitor: Joint optimization software and optimization scripts to call motor design software through optimization scripts, and optimize the motor through the genetic algorithm in the multi-objective optimization software; When the motor is at rated speed, use finite element software to evaluate each candidate parameter in detail; According to the evaluation results, further refinement is carried out through a fast converging algorithm, and finally the parameters of the high-speed generator are selected.

7. A method of designing a dual three-phase fractional-slot winding carbon fiber reinforced high speed electrical generator as claimed in claim 6, characterized in that, The capacitance value of the support capacitor is calculated by the formula: ； ； wherein, is the peak power, is the switching frequency, is the bus voltage, the maximum and minimum values of the capacitance are obtained according to the calculation, and a suitable capacitance is selected in combination with the reliability of the airborne equipment.

8. A dual three-phase fractional-slot winding carbon fiber reinforced high speed electrical generator as claimed in claim 6, characterized in that, The ripple current of the support capacitor is calculated by the formula: wherein, is the bus capacitance ripple current root mean square value, is the motor phase current root mean square value, is the modulation index, is the power factor.

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