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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Jing Chen Yu Chen Lupeng Tong Li Peng The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology (HUST) China

ISBN: (数字)9781728153018

ISBN: (纸本)9781728153025

Explicit model predictive control (EMPC) regards the linear time-invariant model as the prerequisite to deduce the offline control laws for online control. Thus, EMPC cannot be directly applied to Buck converters with variable load. A tradeoff method is to linearize Buck model under a specific load to obtain the time-invariant model to perform EMPC. However, since the obtained offline control laws is derived under the specific load, its performance will be degraded when the load varies. To fix this problem, this paper proposes to utilize state Feedback Linearization (SFL) technology to transfer the variable load term from model parameter matrix to state variables and control parameter. Based on such an equivalent model, EMPC can be directly performed and load-independent offline control laws are obtained. With such a methodology, only the load-dependent state variables and control parameter need to be updated online to adapt load variation, and the obtained control laws need not to be changed and can be discretized into a look-up table to reduce online computational burden, which suits the high switching frequency scenarios well. Details of the proposed methodology are given in this paper. Simulation and experimental results are also provided to demonstrate the effectiveness of the proposed control methodology.

关键词： Adaptation models state feedback Buck converters Predictive models Table lookup Load modeling Predictive control

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Analysis and Design of a Modular 100 kW Stand Alone Power System

Analysis and Design of a Modular 100 kW Stand Alone Power Sy...

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China International Electrical and Energy Conference (CIEEC)

作者： Wahab Ali Shah Ali Shan Hengxin He Habib ur Rahman habib Junjia He State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781538653937

The growing number of energy consuming devices, together with the increasing demand for energy, has led to an energy crisis in the world today. As electricity is an important factor for the development in the economic growth. At this time, the growing population will bring disaster situations relating to electrical energy and pollution; it will affect both the economy and the citizens and make a barrier in the path to complete with developed countries. In order to overcome the epileptic situation of electrical energy and make our environment clean and green. First, we need to give opportunities for renewable energy to address electricity generation. Second, there is no other way to reduce complexity and eliminate energy problem without using solar energy. The solar energy which is renewable energy, environmental friendly and free of cost but still we face difficulty by complete harnessing of solar energy because of variation of irradiation and temperature to get constant point at the output we will use PI controller. Moreover, there is different classification of inverter we used "PWM inverter" that can take steady DC voltage PWM inverter can take in a steady dc voltage. So as to feed solar voltage to the boost converter to step-up solar voltage we used PI controller to control boost converter and get constant voltage at the output the we feed this boost DC voltage to the 3phase PWM inverter to converter into three phase AC voltage. Finally, the inverter should direct the extent and the recurrence of AC output voltages, and the diode rectifiers are required to settle the line-to-line voltage.

关键词： Inverters Voltage control Pulse width modulation Inductors Solar energy PI control Voltage measurement

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Development of a long-lifetime spark gap switch and its trigger generator for 2.0 MJ capacitive pulsed power supply module

Development of a long-lifetime spark gap switch and its trig...

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electromagnetic Launch technology

作者： Li Lee Chaobin Bao Xibo Feng Xiangdong Qi Fuchang Lin State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

Starting from the updated requirements of an advanced laser system, a switch-trigger system for a 2.0 MJ pulsed power supply module has been developed. This paper discusses the design, construction and testing of this switch-trigger system. The two-electrode construction for the spark gap switch was selected due to the superiority in long working life, high peak currents and fast rise-time of currents. The trigger generator based on resonant charging of pulse transformer was constructed. A magnetic isolator and a pressure controller were the auxiliary equipments of this system. In the section about the mathematical principles, the equations of the lifetime and stability of this spark gap switch with graphite electrodes are given. These expressions can be regarded as the design basis of the same type switch. As for the trigger generator, the analysis states that an appropriate ratio can be obtained when using the resonant charging based on core-type pulse transformer. The charging time is dependent on the leakage inductance and the capacitance of the primary and secondary capacitors. Extensive testing has proved the operating parameters of the switches and trigger generator. The measured discharge current waveform of 2.0 MJ capacitive pulsed power supply module is demonstrated to be over 500 kA peak-current and 500 μs pulse-width. And the life test has proved that the switch-trigger system can support more than 200 kC transfer charge. Via replacing the electrodes, the lifetime of this switch can be extended more.

关键词： Switches Pulse transformers Generators Electrodes Sparks Capacitors Magnetic cores

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Sensorless Control of Switched Reluctance Motor Based on Sliding Mode Observer Using Nonlinear Flux Linkage Model

Sensorless Control of Switched Reluctance Motor Based on Sli...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Fanyan Zeng Shuanghong Wang Zixin Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

This paper proposes an improved position sensorless control method for switched reluctance motor (SRM) based on a sliding mode observer (SMO) using nonlinear polynomial flux linkage model. Firstly, in order to balance the accuracy and complexity of SMO, a nonlinear polynomial flux linkage model with variable coefficients is introduced. Then, a modified SMO utilizing the switching function is designed to estimate rotor position and speed. Finally, comparison simulation results are presented to verify the accuracy and robustness of the proposed sensorless method.

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Modified APC Strategy for Doubly Salient Electro-Magnetic Generator With Controlled Rectifier Considering Dramatic Load Changes

Modified APC Strategy for Doubly Salient Electro-Magnetic Ge...

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IEEE International Conference on Power and Power and Renewable Energy (ICPRE)

作者： Zhenyu Lei Shuanghong Wang Zixin Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

The output voltage of the traditional diode-rectified doubly salient electro-magnetic generator (DSEG) system will change significantly when the load current changes rapidly. Besides, it’s difficult to regulate the output voltage by adjusting the field current because of the large time constant. In order to solve the problem, a modified angular position control (APC) strategy based on the controllable rectifier DSEG system is proposed. Using the back propagation neural network (BPNN) to predict proper switching angles according to the speed and field current, the improved APC strategy is helpful to slow down the charge and discharge process of the capacitor and greatly reduced the output voltage fluctuation. Finally, the effectiveness of the proposed strategy is proved by simulations on a 6/4 pole DSEG with controlled rectifier.

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Enhanced visible-light photocatalytic hydrogen evolution using two-dimensional carbon nitride sheets with the removal of amine groups

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Chinese Chemical Letters 2024年第2期35卷 446-450页

作者： Yu Zhang Liting Wu Shaopeng Wang Dingyi Yang Huan Liang Yizhang Wu Jian Hao Youqing Wang Jianke Liu Yong Wang Department of Physics Shaanxi University of Science and TechnologyXi'an 710021China School of Advanced Materials and Nanotechnology Academy of Advanced Interdisciplinary ResearchXidian UniversityXi'an 710126China The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology Xidian UniversityXi'an 710126China Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State MicrostructuresNanjing UniversityNanjing 210093China State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China

Two-dimensional(2D)carbon nitride sheets(CNs)with atomically thin structures are regarded as one of the most promising materials for solar energy ***,due to their substantially enlarged bandgap caused by the strong quantum size effect and their incomplete polymerisation with a large number of non-condensed surface amino groups,the practical applicability of CNs in photocatalysis is *** this study,CNs with broad visible-light absorption were synthesised using a 5-min fast thermal *** removal of uncondensed amine groups reduces the bandgap of CNs from 3.06 eV to 2.60 eV,increasing their absorption of visible ***,the CNs were distorted after annealing,which can differentiate the spatial positions of electrons and holes,enhancing the visible-light absorption *** a result,when exposed to visible light,the photocatalytic hydrogen production activity of atomically thin 2D CNs rose by 8.38 *** research presents a dependable and speedy method for creating highly effective visible-light photocatalysts with narrowed bandgaps and improved visible-light absorption.

关键词： 2D carbon nitride sheets Rapid thermal annealing DFT calculations Visible-light absorption visible-light photocatalysis

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Force ripple minimization of a linear vernier permanent magnet machine for direct-drive servo applications

Force ripple minimization of a linear vernier permanent magn...

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IEEE Conference on electromagnetic Field Computation

作者： Yuting Gao Ronghai Qu Dawei Li Fengxiang Chen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781509010332

Linear vernier permanent magnet machines (LVPMMs) for direct-drive servo applications are attracting more and more attentions due to its high force density, easy maintenance, rapid dynamic response, etc. This paper proposes a new LVPMM structure which has a similar secondary as that of a regular linear PM machine, while its primary mover is composed of three modules, which are separated by flux barriers. Since high-precision servo systems have rigorous demands on the force ripple of the drive motors, two methods are introduced to minimize the force ripple of the LVPMM. One is to choose an optimal design of flux barriers; the other is to change the three-phase winding connection. The effectiveness of both methods are verified by time-stepping finite element analysis (FEA). It is found that the force ripple can be reduced from 10.6% to 2.4%.

关键词： Force Windings Optimization Forging Servomotors Minimization Stators

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Comparison of stator DC-excited vernier reluctance machines with synchronous reluctance machines

Comparison of stator DC-excited vernier reluctance machines ...

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IEEE International Conference on Electric Machines and Drives (IEMDC)

作者： Shaofeng Jia Ronghai Qu Jian Li Yu Chen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

Stator DC-excited vernier reluctance machines (DC-VRMs) are vernier reluctance machines equiped with additional DC field winding in stator to generate the exciting field, a rotating field similar to synchronous reluctance machines (SynRMs). This paper compares the electromagnetic performance of two non-PM reluctacne machines including DC-VRMs and SynRMs. First, the basic operation principle of DC-VRMs and SynRMs are briefly reviewed. Then, four machine models, two DC-VRMs and two SynRMs are designed and optimized for comparison. For a fair comparison, the phase current, current density, slot fill factor and dimensions including the stator outer diameter, air gap and stack length are designed the same. The electromagnetic performance including flux density, torque quality, overload capacity, power factor and losses are compared in detail.

关键词： Windings Torque Stator windings Harmonic analysis Rotors Reluctance machines

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Magnetic Field Effects on Water Electrolysis Performance on a Microfluidic Platform

Magnetic Field Effects on Water Electrolysis Performance on ...

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Sustainable Power and Energy Conference (iSPEC)

作者： Hao Li Ang Lu Tianshu Dong Danji Huang Chaolong Song Jinyu Wen Jiakun Fang Yuan Pan State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

With the rapid development of global low-carbon energy, water electrolysis for hydrogen production attracts significant attention as a crucial energy conversion method. For industrial electrolysis setups, the large-scale application is limited by the issue of low efficiency. To address this issue, one promising approach is to regulate the electrolysis process by imposing an external magnetic field. However, current relevant studies usually focus on static electrolysis systems within beaker-like containers, ignoring the narrow flow channel structure and the circulating flow of electrolyte in industrial electrolyzers. Therefore, an electrolyzer using a microfluidic platform as a phantom is established. Based on the platform, this paper investigates the effects of magnetic field under different magnetic flux densities, electrolysis voltages and electrolyte flow rates. The results indicate that the magnetic field contributes to an enhancement in current density and the increase in current density shows a trend of first increasing and then decreasing with the increase of voltage or flow rate within a certain range. Moreover, The improvement increases with the increment in magnetic flux density.

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Research on Decoupling of Units in Distribution Networks

Research on Decoupling of Units in Distribution Networks

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Xuhua Liu Weiguo Zhang Xiaojie Shi Lei Lin State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

The intricate interactions between substantial line impedance and diverse integration techniques have resulted in a strong coupling among PV inverters, imposing a significant challenge to achieve the independent and efficient voltage/power regulation for PV units. To tackle the challenges, this paper presents a novel approach to decouple distributed PV units connected to a distribution network via different interconnection methods. Firstly, an equivalent line impedance derivation method is proposed to streamline the complex coupled distribution network into a unified "PV unit - line impedance – grid" structure while preserving the node information. Then, a "Line Impedance Equivalent Coefficient (LEC)" is defined to capture the evolving characteristics of the equivalent line impedance. Moreover, by treating the chain structure as a special radial form, the proposed method handles diverse network structures with a minimal computational complexity. Simulation results from Matlab/Simulink demonstrate the effectiveness of this method in decoupling radial, chain and hybrid networks.

关键词： Couplings Simulation Distribution networks Regulation Inverters Hybrid power systems Impedance

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