采用磁电发电机的手榴弹电子触发引信

针对电池供电手榴弹电子引信电池贮存性能差,在使用期内需两次更换电池问题,提出了采用磁电发电机的手榴弹电子触发引信。该引信对磁电发电机进行小型化设计,实现结构兼容;提高磁电发电机发电能量,降低控制电路功耗,实现磁电发电机、电路和火工品能量匹配;改进泄漏电路,对电发火能量彻底耗散。验证试验表明:继承了电池供电手榴弹电子引信多功能、全保险型和机电一体化失手保险成熟技术,解决了电池不能长贮和更换电池不便问题,提高了手榴弹电子引信的贮存性能和实用价值。

相对旋转式磁电发电机

盘式磁电发电机具有功率密度大、轴向尺寸小、可长期存储等优点,在引信中具有很好的应用前景。提出了一种基于相对旋转技术进行发电的引信用磁电式发电机,利用弹丸旋转使引信内部同轴零部件在一定时间内具有相对转速差这一特点作为动力进行发电,从而避免了以涡轮转动作为原动力的磁电发电机的稳定性较差等问题。从原理及模拟实验上论证了相对旋转式磁电发电机用作小口径弹药引信物理电源的可行性。

微型旋转式磁电发电机研究现状

介绍了发电功率在毫瓦至瓦特量级的微型旋转式磁电发电机领域的研究进展。微型磁电式发电机可以将环境中的能量转化为电能,具有可靠性高、发电效率高、适用于恶劣环境、使用寿命长等优点。可用于为传感网络、便携式设备、微机电系统等设备提供持久的能量供给。文章对近年微型旋转式磁电发电机关于提高发电性能的改进方法进行了综述;分析并对比了磁电式微发电机的设计和性能;总结了微型旋转式磁电发电机发展关键技术。对于今后相关领域科研工作的开展具有积极的参考价值。

Variable damping forces caused by electromagnetic energy harvesting with an adjustable load

A novel variable damper using an adjustable energy harvesting structure is proposed for semi-active vibration systems. The fluid flowing in a hydraulic cylinder is employed to drive an electromagnetic generator for harvesting vibration energy, which on the other hand, leads to a damping effect of the hydraulic damper. To make the damping force variable, an adjustable resistor is adopted to tune the capability of energy harvesting. The present approach is validated by both theoretical analysis and experimental evaluation. When connected with different resistance loads, the prototype damper has different equivalent damping coefficients ranging from 3. 987 × 104 to 2. 488 × 105 N· s/m. The results show that the damping force of the damper is variable in response to the adjustable load for the vibration energy harvesting.

Characteristics of permanent magnet linear synchronous motor fed by spwm inverter based on field-circuit coupled method

Presented field-circuit coupled adaptive time-stepping finite element method to study on permanent magnet linear synchronous motor (PMLSM) characteristics fed by SPWM voltage source inverter.In air-gap field where the direction or magnitude of the field is changing rapidly,the smallest elements are demanded due to high accuracy to use adaptive meshing technique.The co-simulation was used with the status space functions and time-step finite element functions,in which time-step of the status space functions was the smallest than finite element functions'.The magnitude relation of the normal elec- tromagnetic force and tangential electromagnetic force and the period were attained,and current curve was very abrupt at current zero area due to the bigger resistance and leak- age reactance,including main characteristics of motor voltage and velocity.The simulation results compare triumphantly with the experiments results.

Magnetic field and performance analysis of a tubular permanent magnet linear synchronous motor applied in elevator door system

A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.

Electromagnetic design and dynamic analysis of large turbo-generator

Through a great deal calculation, the design and simulation analysis of stator parametric and rotor electromagnetic system of 1000MW turbo-generator are performed by using Ansoft Maxwell Rmxprt12.1 software. Besides. the basic parameters of the generator, the geometry dimensions of the stator and rotor, type and sizes of the slots, coils and windings parameters and the way of windings connection are determined. The finite element model of electromagnetic systems of generator stator and rotor was constructed by Ansoft Maxwe112D3D 12.1, and the transient electromagnetic characteristics of generator was analyzed and simulated. The 3D geometric models of turbo-generator were established respectively by using PROE software, and the dynamic finite element model of generator structure was built by ANSYS workbench 11.0. In addition, the dynamic characteristics of stator iron core, stator frame were calculated respectively. The simulation calculation has shown that the structural parameters, material parameters, and the electromagnetic characteristics parameters for large turbogenerator that are put forward by this paper should be optimal. and the design plan and method suggested by this paper should be feasible. The paper provides an effective solution for the development of larger turbo-generator than 1000 MW.

Numerical Experiments of Magneto-convection Using SUPG/PSPG Techniques

The proposed SUPG/PSPG stabilized FEM formulation for incompressible fluid flow simulation is extended to thermo-magnetically driven flows, and is used for the calculation of the direct and sensitivity thermal,fluid flow and electric potential fields. The method is demonstrated through the solution of an inverse problem with known results.

Effects of Uncertainties in the Position and Orientation of Both the Transmitter and Receivers on Marine Controlled-Source Electromagnetic Data

Simulation and interpretation of marine controlled-source electromagnetic(CSEM) data often approximate the transmitter source as an ideal horizontal electric dipole(HED) and assume that the receivers are located on a flat seabed.Actually,however,the transmitter dipole source will be rotated,tilted and deviated from the survey profile due to ocean currents.And free-fall receivers may be also rotated to some arbitrary horizontal orientation and located on sloping seafloor.In this paper,we investigate the effects of uncertainties in the transmitter tilt,transmitter rotation and transmitter deviation from the survey profile as well as in the receiver's location and orientation on marine CSEM data.The model study shows that the uncertainties of all position and orientation parameters of both the transmitter and receivers can propagate into observed data uncertainties,but to a different extent.In interpreting marine data,field data uncertainties caused by the position and orientation uncertainties of both the transmitter and receivers need to be taken into account.

Design and Analysis of Self-excited Miniature Magnetic Generator

Nowadays, electronic devices are more and more integrated into everyday life. These seamless integrations focus on mobility, but at the same time strive to be unobtrusive to the end user. With the introduction of personal data assistants and intelligent cellular phones for the searching of the website, true mobile computing is closer than ever. However, battery technology, which powers most of these mobile connectivity solutions, has not kept up the same pace of improvement. The paper describes a methodology for the design and performance of a self-excited permanent-magnet generator applied to low power supplies. It combines an analytical field model, a lumped reluctance equivalent magnetic circuit, and an equivalent electrical circuit. An illustrated example of a 15-mW, 290-r/min generator is given, and the analysis techniques are validated by measurements on a prototype system.

Optimization control strategy for single-phase permanent magnet generator based on voltage ripple

A method of feedforward compensation for electromotive force(EMF) in the single-phase permanent magnet linear generation system and a research in the performance of the single-phase PMLG system are presented.A general mathematical model for the single-phase permanet magnet linear generator(PMLG) system is established and the current loop,voltage loop and the feedforward control are studied based on it for the control system.Then this paper analyses the transfer function of the power system,optimizes current loop and voltage loop parameters by engineering algorithm,and calculates the optimal control parameters.An EMF feedforward compensation method is developed to optimize the control system which improves dynamic performance of the power system but does not affect the steady-state performance.The result of this research verifies the correctness and rationality of the design for the control system.

Control of the DC Output Voltage of the AC/DC Converter Using Sliding Mode Control： Application to PMSG

This paper presents sliding mode technique associated to the direct torque control （DTC） for an isolated-loaded permanent magnet synchronous generator （PMSG）. The machine delivers an active power to a DC-load via a converter connected to a single capacitor on the DC side. Since the converter/capacitor model is nonlinear, the sliding mode technique constitutes a powerful tool to ensure the DC-bus voltage regulation. The computer simulations are provided to verify the validity of the proposed control algorithm.

MPPT for Hybrid Energy System Using Gradient Approximation and Matlab Simulink Approach

This paper applies new maximum-power-point tracking （MPPT） algorithm to a hybrid renewable energy system that combines both Wind-Turbine Generator （WTG） and Solar Photovoltaic （PV） Module （SPVM）. In this paper, the WTG is a direct-drive system and includes wind turbine, three-phase permanent magnet synchronous generator, three-phase full bridge rectifier, and buck-bust converter, while the SPVM consist of solar PV modules, buck converter, maximum power tracking system for both systems, and load. Several methods are applied to obtain maximum performances, the appropriate and most effective method is called gradient-approximation method for WTG approach, because it enables the generator to operate at variable wind speeds. Furthermore MPPT also is used to optimized the achieved energy generated by solar PV modules.Matlab / Simulink approach is used to simulate, discuss, and optimized the generated power by varying the duty cycle of the converters, and tip speed ratio of the WTG system.

Research on DCC Strategy for Grid-Connected Inverter of D-PMSG under Unbalanced Network Voltage Conditions

According to performance analysis of a three-phase grid-connected inverter mathematical model of a directly-driven wind turbine with a permanent magnet synchronous generator (D-PMSG) under unbalanced network voltage conditions, a dual current-loop control strategy (DCC) oriented on positive voltage and negative current is proposed to inhibit the DC voltage fluctuation. Meanwhile, a notch filter is introduced into the conventional control strategy of a phase-locked loop to complete the low voltage ride through (LVRT) ability of the wind generator. A 1.5-MW D-PMSG with a back-to-back IGBT frequency converter was simulated in the PSCAD/EMTDC environment, and simulation results showed that: the maximum wind power tracking was achieved in this system and the proposed DCC strategy could successfully inhibit the rising aging of DC voltage and enhance the ride-through capability of D-PMSG wind generation system under unbalanced network voltage conditions.

The Least Order Observer Based Sensorless Control of PMSG in Direct-Drive Wind Turbines

Permanent magnet synchronous Generator （PMSG） based direct-drive wind energy conversion system （WECS） has been attracting wide attentions. For the special application, sensorless control for PMSG is desired. By widely studying the previous contributes, a novel estimator based on back-EMF is proposed. The estimator is composed of back-EMF observer and a phase-lock-loop （PLL） control to get the rotor-flux speed and position. The estimator not only can be used for interior and surface permanent magnet synchronous generators, but also has a compact and symmetrical structure, which makes it be beneficial for implementation. Compared with previous strategies, the EMF observer is independent of the PLL control, which would simplify the observer design. Meanwhile, the proposed estimator is less sensitive to parameter variations. Based on mathematic models of PMSG, the proposed estimator was analyzed in detail, and the realizing process was also presented. To validate the proposed estimator, the important experiment results are reported.

A Review of Direct Driven PMSG for Wind Energy Systems

This paper presents a comprehensive overview study of the DDPMSG （direct driven permanent magnet synchronous generator） for wind energy generation system. Wind turbine controls are provided. The PMSG （permanent magnet synchronous generator） is introduced as construction and model. Configurations of different power converters are presented for use with DDPMSG in wind systems at variable speed operation and maximum power capture. Control techniques for the system are discussed for both machine-side and grid-side in details. Grid integration is provided with focus on how to insure power quality of the system and the performance at disturbances.

Analysis and Control of a Three-Phase Switched Reluctance Wind Generator

This paper deals with various aspects of modeling, simulation, analysis, and control ofa SRG （switched reluctance generator） in different modes of operation. Excitation method of such a generator is shortly described. The output power of the SRG is controlled so that it can track the maximum output power of a wind turbine drive applications. Also, the output generator voltage is stabilized under either load or wind speed variations. Basic operational characteristics of a three-phase 6/4 SRG are developed through experimental observation. Meanwhile, the real-time operation was implemented in a DSP （digital signal processor） environment. The simulation of the complete system model has been obtained using the Matlab/Simulink software. A good agreement between experimental and simulation results has been observed which supports the validity of the proposed analysis.

Influence of Excitation System＇s Parameters to the Power System Stability

Excitation system is one of the significant elements affecting the dynamic performance of electric power systems. The power engineering as area of science and industry is subjected to rapid modernization, which is caused by technological progress. However, not all elements of the power system are developing simultaneously. The old type of elements sometimes is sufficient to adapt old system to the new operational conditions. The work developed and proposed in this paper deals with analysis of possible optimization of synchronous generator＇s excitation system. Authors examined influence of excitation system＇s parameters to the dynamics of transient processes in the power system. Authors investigated optimal parameters of excitation system of the Kegums hydro power plant. For optimization of parameters objective functions were used. The problem of the mutual influence of excitation systems of neighbor power plants was investigated. Investigation of transient processes using developed model proved that optimization of excitation parameters improves efficiency of regulation of excitation system, damping of active power oscillation and in some cases can prevent out-of-step condition.

Development of a Renewable Energy Based DC Excitation System in a Micro Hydro Power Plant

MHPPs （micro hydro power plants） have become prominent in hydropower plants as a solution to provide the energy demands of the grid. In this study, a new hybrid renewable energy based DC excitation system for synchronous generator in the developed MHPP system is introduced. Proposed hybrid DC excitation system consists of solar ＆ hydrogen energy based power generating systems. Hybrid renewable energy based system is used for the excitation of the synchronous generator in the MHPP test system. The renewables are used as a secondary energy source to provide the excitation current to a synchronous generator that generates energy in MHPP. A PV （photovoltaic） array is used as the main source of excitation, and a FC （fuel cell） stack is used for DC excitation in the lack of sunshine. In the experimental setup, an electrical control card is developed, and a microcontroller is used to perform the proposed excitation system. All experimental results obtained from 5 kW rated power MHHP test system. Experimental results show that, the proposed method provides the continuous excitation current, and the operation of the synchronous generator is uninterrupted. The proposed method is also practical and easily implemented for MHPP systems.

Influence of Design Parameters on Cogging Torque in Directly Driven Permanent Magnet Synchronous Wind Generators

In order to reduce the cogging torque, this paper investigates the influence of some parameters on the cogging torque developed by directly driven permanent magnet synchronous wind generators. Based on the remanent magnetic flux densities, the cogging torque is computed by using finite element method. It is shown that many parameters have influence on cogging torque and the slot and pole number combination has a significant effect on cogging torque. A simple factor has been introduced to indicate the effect of the slot and pole number combination. Some practical experience to reduce the cogging torque was applied to 2 MW three phase permanent magnet synchronous generator at rated speed of 37.5 rpm for wind energy conversion. The simulation and experiment results verify the effect of the proposed method.