Lithium-ion battery state management faces challenges in joint state estimation accuracy and capacity degradation compensation. This paper proposes a four-state joint estimation method based on an electrothermal coupling model to achieve full life-cycle assessment of State of Charge (SOC), State of Health (SOH), State of Energy (SOE), and State of Power (SOP). First, we construct an electrothermal coupling framework combining the Thevenin equivalent circuit model and lumped parameter thermal model, employing the Forgetting Factor Recursive Least Squares (FFRLS) method for online parameter identification. Second, we establish a multi-time-scale state estimation system, utilizing the Adaptive Extended Kalman Filter (AEKF) algorithm for SOC estimation and the Particle Filter (PF) algorithm for SOH estimation. Third, we calculate SOE based on the SOC-SOH coupling relationship and establish a multi-constraint optimization model to estimate SOP. Experimental results demonstrate that under different temperature and aging conditions, the SOC estimation error remains below 2%, and the SOH estimation error stays below 3%, significantly outperforming traditional single-state estimation methods.

In order to address the uneven current distribution caused by the difference of line impedance in parallel electric power system (EPS) and the bus voltage drop in traditional droop control, this paper proposes an improved droop control strategy that considering the line impedance. Firstly, the influence of line impedance on current distribution accuracy is analyzed. Subsequently, the line impedance is taken into account in the droop coefficient to achieve equal current distribution. On this basis, a voltage compensation link is added to compensate for the busbar voltage drop caused by the initial droop coefficient. Finally, to verify the effectiveness of the proposed control strategy, a simulation model of a 3 -stage generator high voltage DC (HVDC) parallel EPS was established, and the simulation results of three control methods are compared. The results show that the control strategy proposed in this paper can improve the defects of traditional control method, while also achieving both bus voltage regulation and average current distribution.

The practical power-added-efficiency (PAE) of class-D RF power amplifier (PA) deviates from the theoretical value 100% greatly because of some inevitable non-ideal effects. This paper proposes three design considerations to improve the performance of class-D RF PA. Based on those design considerations, two pieces of class-D RF PA, powered by 1.8V and 3.3V supply respectively, have been implemented by standard CMOS 0.18um process. With 800MHz stimulus, measurement results show that the PAE and output power reach 42% and 10.5dBm for 1.8V supply part, 38% and 15.4dBm for 3.3V supply part, which demonstrates the practicability of the introduced design considerations.

Background: During cable operation, its internal temperature reflects the actual working condition of the cable. Once overload occurs, its conductor temperature will rise rapidly. Under high temperature conditions, the insulation material is very prone to breakdown accidents, which seriously threatens the safety of the power system. Methods: To reflect the actual operating condition of cables with high fidelity, a cable temperature mapping model is proposed with the coupling of electromagnetic and thermal field taken into consideration. Firstly, a finite element model is formulated based on the cable structure and material parameters. Secondly, the coupling between electromagnetic and thermal field is analyzed, and multiple coupling calculations are performed iteratively according to the operating conditions. Finally, the mapping between temperature and current flowing through the cable is established to accurately reflect the variation of cable’s internal temperature under different operating conditions. The cable surface temperatures under five operating conditions are measured online and compared with the calculated results of the temperature mapping model. Results: The absolute error between the calculated value of the model and the actual measured value is 0.88°C and the relative error is 1.46%. Conclusions: The temperature mapping model developed in this paper can accurately calculate the internal temperature of the cable and forms an important part of the digital twin model of the cable.

Due to the aircraft power generation system with its parameter uncertainty and external disturbances of sudden loading/unloading of high power and nonlinear loads, the traditional PI control can no longer meet the requirements of high-quality power supply, and the robustness is poor. Therefore, this paper applies the H-infinite control theory to the three-stage brushless DC power generation system and designs the H-infinity voltage regulator to improve the dynamic performance of the system by reasonably selecting the sensitivity weighting function. The simulation platform of the three-stage brushless DC power generation system is built in Matlab/Simulink and compared with PI control. The conclusions show that the H-infinity voltage regulator designed in this paper can effectively suppress the voltage fluctuation caused by external interference, improve the steady-state and dynamic performance of the system, and has strong robustness.

As aircraft electrical grid scales and complexities increase, conducting research on real-time simulation techniques for power systems becomes crucial for aircraft electrical grid design and testing. This paper analyzes the principles of the State Space Node (SSN) algorithm and employs this method to dissect the simulation model of a More Electric aircraft electrical grid. Using the RT-LAB platform, we have accomplished model compilation, configuration, connection, and model download, successfully achieving the goal of real-time operation for the entire electrical grid model.

Compared with civil cables, aviation cables operate with lower voltage but higher temperature. Thermal stress is the main factor associated with cable lifetime. Without considering the variance in the insulating material's thermal parameters, traditional models fail to calculate the temperature and lifetime of aviation cables accurately. To accurately calculate the internal temperature of aviation cables and achieve lifetime prediction, an improved electromagnetic-thermal coupling model and a new lifetime model of cables are proposed. The cable temperature is measured to verify the high fidelity and accuracy of the improved model. With real-time measured current and temperature, the online prediction of cable lifetime can be realized.

As more and more powerful electronic devices are connected to the aircraft power system, the load power of the system presents pulsating characteristics. To make the aircraft high-voltage DC power supply system meet the power demand with pulsating load, an optimized configuration of the aircraft 270V high-voltage DC power supply system based on two-stage filter distribution is proposed. According to the response characteristics of the power supply, the two-stage filtering distribution strategy is adopted to determine the power of each power supply response; A comprehensive optimal configuration model considering the weight and efficiency of the power supply system and the constraints that the power supply operation system needs to meet is established; The particle swarm optimization algorithm is used to solve the model; By comparing the optimal configuration results of the power system with the two distribution strategies of the generator response average power and two-stage filtering through the calculation example, the configuration results show that the overall weight of the power system is reduced by 115.2kg and the system efficiency is increased by 12.21% by using the method in this paper. The optimization results reflect the advantages of the method in this paper, and the simulation analysis verifies the correctness of the configuration results.

To enhance the efficiency and power density of switched-mode power supplies, planar air-core magnetic components have gained more and more popularities. Without magnetic core to restrict flux, conventional reluctance model cannot be applied to solve inductance for planar air-core magnetic components. Based on uniform mesh and Neumann's formula, this paper proposes an analytical model to calculate inductance of planar air-core inductors. With simulation or measurement results as the benchmark, relative error of the proposed model is less than 10 % in wide dimension range. More importantly, compared with other existing models in literature, the proposed method has better accuracy and generality. The proposed model can be applied to solve inductance and do optimal design for planar air-core inductors.

Whale optimization algorithm (WOA) has been successfully applied to address the engineering optimization problems. However, lacking of population diversity leads to that WOA is easy to fall into local optimum. To address this gap, this paper proposes opposition-based learning chaotic whale optimization algorithm (OBLCWOA), which is an improved form of WOA. OBLCWOA uses chaotic mapping to generate key random parameters and opposition-based strategy is utilized to enhance the diversity of the population. Those two strategies can effectively improve the convergence speed, convergence accuracy and global search capability. Subsequently, the OBLCWOA is simulated using 23 standard test functions, and the results show that the global search capability, convergence speed and convergence accuracy of the OBLCWOA are significantly improved compared with the WOA and QWOA. Finally, three solar cell models are constructed, the parameters of which is identified by OBLCWOA. The simulation data are compared with the measured data by constructing the fitness function. Experimental results provide evidence on the ability of OBLCWOA in solar cell parameter identification.

Avionic data bus is an important channel to transmit information for aircraft control system and mechatronic system. Once it occurs a disconnection or short circuit fault, the communication of control system would fail and man-machine safety would be endangered. In this paper, several reflection methods are introduced. Among them, Spread Spectrum Time Domain Reflectometry (SSTDR) is emphatically discussed. The feasibility of applying SSTDR to fault detection and location of avionic data bus is analyzed theoretically. The transmission characteristics of several typical avionic data buses are introduced, and the reliability of communication under the interference of detection signal is analyzed. The amplitude and attenuation of SSTDR signal applied to data transmission bus is calculated. Simulation and experimental verification proves that the fault detection and location of avionic data bus using SSTDR method can ensure the accuracy, low bit error rate and feasibility.

With the benefits of light weight and high power density, lithium-ion battery has been widely used in more-electric aircraft. However, its weak reliability raises our concern. Therefore, in order to maintain the safe operation of aircraft, it is worth implementing real-time state monitoring and lifetime prediction for lithium-ion battery. This paper proposed a monomer model of lithium-ion batteries based on partnership for a new generation of vehicles (PNGV) model and estimation of the state of charge (SOC). Then, the accelerated aging test was carried out using the proposed model based on Dymola platform. At the same time, particle filter algorithm is applied to evaluate the state of health (SOH) of lithium-ion battery. In this paper, the effectiveness of the proposed method was verified by simulation and experimental data.

This paper combined regular characteristic of a LEO satellite orbit control to construct a quantity prediction model for orbit control with correlation analysis of feature parameters in abundant data. And a prediction method of LEO satellite orbit control effect based on multiple regression analysis model was proposed, which had been verified effectively in the actual orbit control. This method could be used as an auxiliary technique to evaluate the traditional orbit control effect for LEO satellite.

The extraction of solar cell model parameters is of great value for diagnosing the ageing fault of solar cells and predicting the life of solar cells. Aiming at improving the accuracy of solar cell parameter extraction, quantum theory is introduced to enhance the algorithm's global search ability and local mining ability of whale optimization algorithm. The extraction of solar cell model parameters are carried out with the whale optimization algorithm and the Harris Eagle algorithm at the same time. The comparison and results proved that the QWOA(quantum whale optimization algorithm) has high accuracy and rapidity in the extraction of solar cell model parameters.

The reliable operation of the aircraft power supply system is an important factor in ensuring the safe flight of the aircraft. Taking an aircraft HVDC power supply system as an example, a reliability assessment method suitable for large aircraft power supply networks is introduced. With the goal of ensuring that all bus bars are supplied with power, the method uses graph theory and other related knowledge to transform the aircraft power supply network into a cyclic directed rooted communication network. Thereby converting the problem into solving the network%s rooted communication reliability; then using factoring algorithm performs binary tree decomposition on the generated rooted communication network to gradually reduce the network scale, and put forward the rules for selecting points that can improve the efficiency of the algorithm. Finally, in the process of generating the binary tree, the overall reliability function of the network can be obtained, so that typical reference indicators such as reliability and MTBF can be calculated.

This paper proposed a disturbance rejection control method based on linear quadratic (LQ) for nonminimum-phase discrete-time systems with unmatched signals. By introducing a new cost function that considers the influences of disturbance on the input signal, we apply the novel control method to hypersonic flight vehicle (HFV) system to solve the problem of turbulence compensation. A two-component control input is generated through systematic derivation of finite-time LQ optimal control law, improving the stability, output regulation capability, and robustness of the HFV system. Comparison analysis under different control schemes in simulation study shows the effectiveness of the proposed method.

316L stainless steel has excellent mechanical properties and good corrosion resistance. It is used as a medical implant material, but it is susceptible to pitting corrosion to precipitate harmful ions and lead to the failure of the material. To solve the above problems, the surface modification method is used to solve it, and it is now widely accepted. Among them, magnetron sputtering technology has been widely used because of its advantages such as good adhesion and other advantages. The parameters of the RF magnetron sputtering process have a great influence on the performance of the coating, and the influence of each parameter has a non-linear mapping ability. The artificial neural network is used to build a model to predict the performance of the coating. It is highly targeted and practical. The establishment of artificial neural network is a prediction model from sputtering process parameters to coating performance, which can save pre-research time and improve work efficiency. The establishment of artificial neural network uses the strong nonlinear mapping ability of artificial neural network, combined with the measured value of Hf-based coating performance to establish a model to predict the effect of Hf-based coating sputtering process parameters on the performance of the coating. The simulation results indicate the prediction The error between the value and the measured value meets the BP network design requirements ≤0.3.

Generator voltage regulator is an indispensable part of maintaining the normal operation of diesel generator set, which plays an important role in the safe and stable operation of the generator set. At present, there are mainly two types of regulator named transistor-based analog voltage regulator and microprocessor-based digital voltage regulator. In view of the advantages that the digital voltage regulator has incomparable with the traditional analog voltage regulator, this paper designs a digital voltage regulator based on the TMS320F28335 chip for a certain type of vehicle diesel generator. The input and output interface circuit of the digital voltage regulator is designed, including the analog conditioning circuit, the digital conditioning circuit, the excitation main circuit and the excitation driving circuit, etc., to fabricate the power board. The software minimum control system is designed by using the DSP minimum system with TMS320F28335 as the core controller, and the voltage and excitation current double loop adjustment mode is adopted. Set up a system experiment platform to test the regulator to meet the expected functional requirements.

Laser Power Transmission (LPT) technique features high energy density, flexible devices and advantageous orientation ability, making itself extremely promising for realizing long-distance, high-power wireless power transmission. Laser diode (LD), a core component in LPT system's transmitter, realizes power conversion from electricity to high-intensity laser beam. LD's performance significantly affects the efficiency of LPT transmitter. Different driving current patterns lead to different electro-optical conversion efficiency (EOCE). The paper presents a novel LD driving strategy for optimal EOCE under different working conditions. To precisely estimate EOCE of LD, a simplified LD equivalent circuit model with only five parameters is proposed, which can readily be adopted to characterize any commercial LD using curves given in their datasheets. Though simplified, the model can still depict the power-current-voltage (P-I-V) characteristics well, and its accuracy is shown to be as close as its traditional counterparts. Based on the model, the optimal driving current strategy for maximum EOCE is derived for all optical power output conditions. A four-phase interleaved Buck converter is constructed to verify the proposed driving strategy. As all experimental results indicate, the proposed method enjoys a fine performance in improving LD's EOCE.

A portable electrochemical impedance spectroscopy (EIS) system has been developed based on FPGA for bio-detection. FPGA is a programmable signal processing chip, which cooperates with DAC module to generate the sweep excitation signal, controls ADC module to perform dual channel acquisition of voltage of a peripheral circuit, performs FFT and parameter calculation and transmits the result to PC for data processing. Based on FPGA internal programming, the system greatly reduces the size and achieves a single multi-frequency measurement, which enhances integration and portability of the system. The measurements of the electrical equivalent circuit by using the EIS system is compared with a high-precision commercial ZX70A impedance analyzer in the range of limited frequency of 100 Hz -500 kHz. The result shows that the maximum relative error of amplitude and the maximum absolute error of phase are 2.42% and 0.936 degrees, respectively. Finally, the EIS system is used to measure electrical impedance change during egg heating. The result shows that the impedance amplitude of egg decreases linearly with the increase of heating time and electrical characteristics of raw eggs and heated eggs are significantly different. These results verified that the developed EIS system achieve portable high-precision measurement of biological tissue.