基于ARM的变温空调伺服系统设计

基于ARM的变温空调伺服系统设计

 Temperature-adjusted air-conditioner is a temperature followed system which is based on "indoor microclimate" principle in medical aerography. Compared with traditional air-conditioner, it does not preset value for indoor environment, but intelligently controls indoor temperature Block neodymium magnet

http://www.chinamagnets.biz/Neodymium/Block-neodymium-magnet.php according to outdoor temperature variety. Temperature-adjusted air-conditioner emploies semiconductor refrigerator as cold (hot) source, Brushless Direct-Current (BLDC) motor as execute outfit, it realizes the rapid follow and adjusts indoor temperature with outdoor temperature.Temperature servo system used as execute outfit is a subsystem of temperature-adjusted air-conditioner. Based on the principle of temperature-adjusted air-conditioner, a kind of digital servo control system with ARM (Advanced RISC Machines) microchip LPC2214 as its core is presented.The whole structure and control scheme of the system, realization methods for all parts have been analyzed in detail, then, the feasibility of design is demonstrated, and hardware circuit is designed. The hardware circuit of temperature servo system uses digital temperature controller with LPC2214 as its core, the system samples indoor and outdoor temperature signals with temperature sensor DS1820, and displays all kinds of parameters with LCD module.Aimed at BLDC motor, which is the execute outfits of temperature servo system, a kind of power driven circuit which uses power MOSFET and gate driven integrate circuit IR2130 is designed for servo system. The BLDC motor can be driven effectively by selecting bootstrap components reasonably and protecting power component correctly.On the basis of characteristic of temperature servo control system, a kind of control arithmetic based on tri-loop model with indoor temperature, rotate speed and current has been presented. The speed-adjusted program of temperature servo control system has been written with C language, compiled, linked and run in ADS (ARM Developer Suite) environment successfully.The BLDC motor di-loop model has been established in MATLAB environment, and the PED parameters of speed loop and current loop are fixed on with Ziegler-Nichols method, which provides reference for actual design. 更多还原

Research of the Testing Platform for Oil-Damper Based on AC Servo System

Research of the Testing Platform for Oil-Damper Based on AC Servo System

The increasing operating speed of the railway locomotive and vehicle put a higher demand on the dynamic performance of the train.Accordingly,the performance neodymium prices

http://www.999magnet.com/products/142-neodymium-prices indexes of the oil-damper should be improved,because,the oil-damper is a key part for ameliorating the dynamic performance of the train and improving the comfortable degree of the passenger.At present,we have imported and produced multifold oil-dampers which can satisfy the demand of high-speed railway,and established a new standard of railway industry for testing the oil-damper.As the testing equipment of the oil-damper, the oil-damper test-bed should be invented urgently. In order to provide convenience for the engineers or researchers when they study on the performance of the oil-damper,the paper aims to constructing a measurement and control platform for oil-damper testing,which can be easily used and is suitable for the high-speed railway. According to the relevant technical requirements, the whole scheme of the testing platform for the oil-damper is researched on, and the working principle of the platform is specified based on the scheme.The paper designs the hardware and software of the measurement&control system for the test-bed.Hardware part begins with the introduction of the hardware structure of the system. Then,the data acquisition and control unit has been designed and implemented in detail,which is the hardcore of the system and includes the Intel 80C196 MCU-based dual CPUs module, switching signal interface circuit, limiting guarding circuit and CAN communication interface circuit. Meanwhile, the paper focuses on the function and the hardware implement of the signal modulation unit and the position regulator.Finaly, the paper introduces the anti-interference measurements which are used in the process of hardware designing.The software of the lower computer for the measurement&control system is composed and its detailed flowcharts are illustrated. The manner of software program is written by assemble language, which includes the main CPU program and the SPWM signal generated program.The fundamental principle of PMSM vector control strategy and SVPWM algorithm are studied. According to these theories, the paper simulates the AC servo system of the test-bed, and then analyses the simulation results.A testing system is constructed, in which the no-load test and simulation test are carried out. Experimental results show that the oil-damper test-bed which is designed by 更多还原

Determination of Contamination in the Complex Compost System Based on Enzyme Biosensor and Immunochemical Analysis

　　Determination of Contamination in the Complex Compost System Based on Enzyme Biosensor and Immunochemical Analysis
　　In this paper, the feasibility of application of biosensor to determine the contamination in the complex compost system is basically reviewed. With the work we have accomplished by far, enzyme biosensor and immunosensor based on the immunochemical analysis which is used to detect the pollutant in the complex compost system were studied.Composting Neodymium Magnets technology is applied to disposal of the municipal solid waste increasingly. With the enhancement of the demand of environment quality, there should be a set of detecting methods to match the correlative standard of environment protection. Due to the complexity, diversification and uncertain characteristics of the complex compost system, the commonly used analytical methods, such as spectrophotometry, gas chromatography and high performance liquid chromatography (HPLC) based on the absorbance spectra, are probably interfered by the interference of substrate turbidity and light disturbance, and the pretreatment of the samples is cumbrous and time-consuming, and the instruments are expensive and ponderous. However, biosensor is known for its superior sensitivity, stability, reusability, selectivity, portablity and other obvious advantages.
　　The operation efficiency of compost system will be improved much if biosensor is applied to detect the pollutant in compost.First, a biosensor was developed and used to analyze the concentration http://www.999magnet.com/products/110-sintered-neodymium-magnets of phenols in compost extracts based on the immobilization of laccase on the surface of modified magnetic core-shall (Fe3O4-SiO2) nanoparticles. Laccase does not need H2O2 as co-substrate or any other co-factors for its catalysis. It can directly catalyse the oxidation of phenols accompanied by the reduction of oxygen. Laccase was convalently immobilized by glutaraldehyde on the magnetic nanoparticles which were modified with amino groups on the surface. The obtained magnetic bio-nanoparticles were attached to the surface of carbon paste electrode with the help of a permanent magnet to respectively determine catechol and hydroquinone.
　　The immobilization matrix provided a good microenvironment for retaining the bioactivity of laccase. The linear range for catechol and hydroquinone determination are 7.5×10-72.75×10-4 mol/L and 1×10-71.375×10-4 mol/L separately, with a detection limit of 7.5×10-7 mol/L and 1.5×10-8 mol/L, respectively. The current reaches 95% of the steady-state current within about 70 s. Catechol and hydroquinone concentration in compost extracts were determined by laccase biosensor and HPLC, the results of the two methods were approximately the same.Next, an on-line system of detection and prediction by artificial neural network (ANN) as a chemometric tool was built to determine the contamination in compost system more effectively. It was a further study based on the laccase biosensor which we have developed. ANN model is a so-called“black box”as it does not need any model structure specification, and due to the strong learning capability and adaptability of ANN, it can be applied to treat the dynamic, nonlinear and uncertain properties of the complex composting system to realize the soft-determination.
　　The performance of the ANN model was compared with the regression model in respect to simulation accuracy, adaptability to uncertainty, etc. All the results show that the combination of amperometric magnetic materials enzyme sensor and artificial neural networks is a rapid, sensitive and robust method in the quantitative study of composting system. Though the ANN model we obtained is a primary model, it can pave the way for further model of more complex system.Finally, the immunochemical analysis was used to detect picloram, an environmental hormone. Picloram as a hapten was coupled with BSA through 1-Ethyl-3-(3-dimethyllaminopropyl)carbodiimide hydrochloride (EDC), obtaining an antigen with immunogenicity and reactogenicity. We injected the obtained antigen into rabbit to get immunity, and then got the antibody of picloram. The double immunodiffusion test and ELISA assay were used to identify the titer and performance of the antibody. In the future, we are ready to develop an immunosensor to determine the picloram in the compost and XiangJiang River. The antibody is immobilized on the slide glass, and then the Fluorscence (FITC) is embed into the liposome modified with the picloram-antibody. The liposome embed with FITC can be used as a signal magnifier to realize the fluorescent detecting technique.

The Research on Detection of Phenols in Garbage Compost Based on the Method of Enzyme Biosensor-BP Neural Network

　　The Research on Detection of Phenols in Garbage Compost Based on the Method of Enzyme Biosensor-BP Neural Network
　　Phenols are widely exist in the environment.As hazardous substances they do harm to the health of humankind.Solving the problem of detection of phenols is urgent for us which also makes significant sence to environmental monitoring.Currently high performance and spectrophotography are applied for the detection of phenols most.However there are some disadvantages in these methods.The former needs a predissociation of the sample while the latter can be interfered by impurities.Furthermore in neodymium prices the procedure of the former’s dissociation needs a pretreatment which will cost much time while the detection instruments are very expensive and unportable.So the two methods are not perfect.It is very important for us to look for a new method which can be applied for rapid and low cost on-line detection of phenols.In recent years,people use enzyme biosensor for the detection of phenols which can reach a satisfied purpose and also offers a tech support for rapid and low cost on-line detection of phenols.
　　The study results of experts both home and abroad are summarized in this paper.The author also make some studies on the detection of catechol based on the method of enzyme biosensor.In this paper a catechol biosensor was developed and used to analyze compost extracts based on the immobilization of laccase on the surface of modified magnetic core-shall (Fe3O4-SiO2) nanoparticles. Laccase was convalently immobilized on the magnetic nanoparticles by glutaraldehyde,which were modified with amino groups on its surface.The resulting magnetic bio-nanoparticles were attached to the surface of carbon paste electrode with the help of a permanent magnet to determine catechol.The detection of catechol based on the method of enzyme biosensor also http://www.999magnet.com/products/142-neodymium-prices exists disadvantage(for example in certain sectors phenol class matter density and highly effective liquid phase chromatography examination result could not very good fitting)so we propose enzyme biosensor examination catechol with the method of neural network.We has established the enzyme sensor-BP neural network examination catechol density model.A BPNN which has one concealed level was established.Here,We use BPNN,because it can be learned and forcasted easily.We obtain the data with the experiment to carry on the training and the test,finally use the network which the training completes to the data to carry on the fitting,We discovered the forecast data and the highly effective liquid phase chromatography obtain the data can be the basic fitting.Thus it can be seen,application of enzyme sensor-BP neural network method examining catechol density obtains the result which is quite ideal,and also provides a new method for fast,real-time examining the density of the phenol class matter.

Research on Production of Polyhydroxyalkanoates by Aerobic Dynamic Feeding Approach

　　Research on Production of Polyhydroxyalkanoates by Aerobic Dynamic Feeding Approach
　　Over the past years, the nondegradable petrochemical plastics accumulating in the environmenthas exacerbated the problem of disposal of solid waste. In response to the problem and harmfuleffects of the plastic wastes on the environment, there is considerable interest in the developmentof biodegradable plastics. In the latest decades, polyhydroxyalkanoates (PHAs) have attractedincreasing interest as an alternative to petroleum-derived plastics for it having similar mechanicalproperties to those of polypropylene, meanwhile, with the additional advantage of beingcompletely biodegradable, biocompatible, and produced from renewable resources.Among the magnetic materials methods, for industrial production of PHAs, the aerobic dynamic feeding (ADF)approach by activated sludge is the most promising because of high PHA accumulation,meanwhile, this method could substantially decreasing the cost of PHA and increasing theirmarket potential for using activated sludge and renewable sources obtained from waste organiccarbon.
　　A number of studies have been carried out on PHA production with activated sludge underADF conditions, but it is still few study on the cultivation of microorganism with high PHAstorage ability by activated sludge from municipal wastewate treatment plant under ADFconditions. There is also no studies reported about the effect of magnetic field on the synthesis ofpolyhydroxyalkanoates by activated sludge under ADF condition.Our work aimed at these two problems and the effect of permanent magnetic field on theproduction of polyhydroxyalkanoates(PHAs) by activated sludge under ADF conditions and thecultivation of microorganism with high http://www.999magnet.com PHA storage ability by activated sludge from municipalwastewate treatment plant under aerobic dynamic feeding conditions was evaluated.
　　The results were as follows:1) It was effective of acclimating activated sludge by gradually increasing organic load underADF conditions. The effect was depend on the the start-up organic load as well as its increasingrate and the "feast"/"famine" ratio. The content of PHA in biomass increased from 1.24%to40.62%when the organic load increased gradually to 6.48gCOD/l in 30 days with the start-uporganic load was 1.096gCOD/l and the "feast"/"famine" ratio was 1: 1,but the system was unstable. Whereas, the content of PHA in biomass increased from 8.74%to 50.24%when theorganic load increased gradually to 6.48gOOD/l in 35 days with the start-up organic load was0.36gCOD/l and the "feast"/"famhae" ratio was 1: 3, meanwhile, the system was stable. Thelower organic load during start-up will benefit to drivie the system toward one "steady-state"where storing biomass will be dominating the microbial consortium. In order to avoid selecting formicroorganisms with a growth response, after the selection at the lower organic load occurred, theorganic load must be further increased step by step and the "feast" phase could last too long.2) The static magnetic exposure had definitely infuenced the biosynthesis of PHAs and theeffect varies with field strength and substrate. It is different polyester synthases that engaged in theproduction of polymers varied http://www.999magnet.com with different substrates. The effect of static magnetic on differentpolyester synthases was dissimilarly. It was demonstrated that, under the same operationconditions, hydroxybutyrate(HB) content in biomass and storage yield reached the maximum at6.7mT, the minimum at 42mT. Whereas, hydroxyvalerate(HV) content in biomass and storageyield reached the maximum at 21mT, the minimum when without magnetic field.

Numerical Calculation and Experiment of High Temperature Superconducting Magnetic Bearings

　　Numerical Calculation and Experiment of High Temperature Superconducting Magnetic Bearings
　　The applications of the high temperature superconductor (HTS) become promising due to development of the manufacturing process and improvement of superconducting properties.Because of the flux pinning properties of the HTSs,the superconductors can be levitated stably on the permanent magnets (PM) ,which are entirely passive and do not require any active control systems. The high temperature superconductors were applied to the magntic systems;for example, the high temperature superconducting magnetic Neodymium Magnets bearings,as a kind of magnetic bearings,have the properties of no contact,no friction ,long life and simple structure etc.So the HTS magnetic bearing has been a subject of considerable interest for the last decade all over the world.First the structure and properties of magnetic bearings are depicted,and the development status and future application are introduced in the introduction.The most important parameters of the HST bearings were the levitation force and stiffness.Based on the critical state model and current vector potential,the electric current distribution were calculated by the finite element method(FEM),then the force and stiffness can be computed by the Lorentz http://www.999magnet.com/products/110-sintered-neodymium-magnets formula.A convenient application software which can be used to calculate the force of HTS bearings was developed by author.The parameters which influenced the bearing system were researched by the software.The parameters include the dimensions of the PMs and HTSs,the critical current density and the positions.Results calculated by the software were compared with the experimental results, and the simulated results and experimental ones correspond to each other. Several HTS axial bearings which had different structures and dimensions were simulated by the software, and got the force and current distribution which can be the theoretic foundation of the design and optimize of the HTS bearings.

Study on the Control System of Vary-Frequency Air Conditioner

　　Study on the Control System of Vary-Frequency Air Conditioner
　　With the arrival of the energy source crisis worldwide, governments in many countries have been promoting the energy saving techniques positively. As the main energy consuming equipment in family, traditional air conditioners are withdrawing from the market gradually because of its low efficiency. Thanks to the advantages of high efficiency, energy saving and more comfort, new generations of the variable frequency air conditioner have become the developing trend from now on. The manufacturing technique of the variable frequency air conditioner in our country, started rubber magnetic sheet from early 1990’s, is still immature up to now. Combining the advanced technology in this field, the author has designed an intelligent variable frequency air conditioner controller.Variable frequency air conditioner is the future of household air condition. Permanent magnet brushless DC compressor has found wide applications due to their high efficiency and the convenient way of control. Generally speaking, the drive of brushless DC motor requires a position sensor to offer proper commutation to the controller. The application of completely sealed compressor can not adopt to the sensor because of its low reliability at high temperature. The technique of sensorless drive for brushless DC motor is now receiving public attention.
　　This paper makes a comprehensive view of the rising, development and present situation of control technique for brushless DC motor, and application foreground of brushless DC motor on household air-condition is introduced. Configuration and principium of brushless DC motor are briefly explained.Fuzzy control techniques have certain amounts of applications in air conditioner control recently. Their fuzzy rule bases, which are the key sections of the fuzzy controller, have been decided by expert experiences in advance. Most of them could not be regulated during the process, easily causing http://www.chinamagnets.biz/rubber/rubber-magnetic-sheet.php the problem of controlled parameters over regulating and fluctuating. According to the air conditioners’ working characteristics, a novel fuzzy controller, named adaptive rules continuously correct fuzzy controller is designed in this paper. The experiments have proved that this fuzzy controller has the advantages of fast response rate, low overshoot and good stability.A specially designed digital signal processor (DSP) for motion control has been chosen in this paper. Its powerful functions provide the best development platform for air conditioner controller. Using DSP chip as the core of the control system, this paper applied voltage modulation (PWM) for the continuous control of compressor. Using the intelligent power module (IPM) has improved the performance of the system, especially for the reliability characteristics. Software and hardware’s design of the system based on TMS320C241 are briefly introduced. The reliable protection of the system and the control of sensorless brushless DC compressor and brushless DC fan motor are realized. At the same time, the deterioration of the controller brought by brushless DC motor reversing to generate electricity in starting process has been resolved.Software design work mainly includes programs for indoors unit control, outdoors unit control and communications between these control. This paper has provided the flow diagrams of the main programs.

Study on Multiresponsive Microcapsules and Their Targeted Drug Release Properties

　　Study on Multiresponsive Microcapsules and Their Targeted Drug Release Properties
　　In this study, a novel targeted carrier of drug release was fabricated by the layer-by-layer self-assembly. Natural polyelectrolytes chitosan and sodium alginate, magnetic nanoscale Fe3O4 particles, and lipid with negative charge or amphipathicity were adsorbed onto monodispersed colloids and drug microcrystal via self-assembly. A type of pH-, thermo- or magnetic-sensitive microcapsule was obtained.Chitosan and sodium alginate have been alternately adsorbed onto polystyrene(PS) microparticles by the layer-by-layer self-assembly. Hollow microcapsules with a diameter of 2-3μm Cast Alnico Magnet were obtained, after the removal of the templates. We investigate the drug loading performance of the microcapsule, in the model of water-soluble drug doxorubicin hydrochloride (DOX). The drug loading amount can vary through changing drug feeding concentrations, salt concentrations, pH, temperature and layer number. The drug loading amount could reach to 224μg per 1mg microcapsules. The drug release rate is faster in low pH value, which demonstrates pH-sensitivity of the microcapsules.CaCO3 microparticles were used as template in self-assembly, to obtain better biocompatible microcapsule. The micron-sized CaCO3 particles were synthesized in the existence of carboxylmethyl cellulose (CMC) .The diameter of the particles differed from 2μm to 8μm with the different addition.
　　The same components were adsorbed onto CaCO3 particles, following with core removal. The drug loading amount can vary through changing salt concentrations, pH, temperature and layer number. The drug loading amount could reach to 312μg per 1mg microcapsules, which larger than that of the microcapsules made by PS. In the drug release system, the drug released fraction reached to 60% after 14 hours, which larger than that of the microcapsules made by PS.Ibuprofen (IBU) microparticles were encapsulated by http://www.chinamagnets.biz/Alnico/Cast-Alnico-Magnet.php chitosan and sodium alginate through layer-by-layer self-assembly and the core-shell particles were obtained. Because of the different dissolvability in pH1.0 HCl solution and pH7.4 PBS solution, the former dissolving rate of core-shell particles is faster. The encapsulation of IBU do not effect so much in delaying the burst release of IBU.The 45% DOX releasing fraction from microcapsules changed from 7h (without lipid layers) to 9h, 12h, 11h, after self-assembly with liposome of different lipid components (DPPC, DPPA, 90%DPPC-10%DPPA, respectively). Lipid layers enhanced the targeting of microcapsules as drag carriers.Magnetic microcapsules were fabricated by adsorbing Fe3O4 nanoparticles, which gathered to the permanent magnet. Precise targeting could implement by the magnetic microcapsules via magnetic field.

Study on a Seperated Magnetic Circuit Magnetic Bearing System and Its Related Problems

　　Study on a Seperated Magnetic Circuit Magnetic Bearing System and Its Related Problems
　　The principle of a magnetic bearing is that the rotor is suspended by dynamic electromagnetic force, to realize no touch support between the stator and the rotor. Because of these advantages such as no wearing, without lubrication and suitable for operating at high speed, magnetic bearings are widely applied in high speed and ultraclean situations, for neodymium prices example, in high speed main axis, flywheel in satellite, etc. In hybrid magnetic bearings permanent magnet is used to produce bias magnetic field instead of electromagnetic field, which reduces the electric loss and also mechanical volume of the bearing, and becomes an important development aspect. Therefore, the study on theses magnetic bearings processes important meanings to their engineering applications.The working principle and development of the magnetic bearing are introduced in this paper first. On the basis of previous work, a novel structure magnetic bearing is designed here. According to the structure and working principle of the magnetic bearing, the mathematical model is derived, which proves the principle of the magnetic bearing is correct theoretically.http://www.999magnet.com/products/142-neodymium-prices The magnetic field of the magnetic bearing is generally computed and analyzed with three dimensional FEM tool Flux3D. Computation results of static characteristics certify that the magnetic coupling between X and Y dimensions is far smaller than that of traditional hybrid magnetic bearings.On the basis of mathematic model of the magnetic bearing, the simulation model of the whole magnetic bearing system is constructed. PID control method is adopted in the process of simulation. Finally the simulation results are deeply analyzed.According to the demand of the whole magnetic bearing, a differential transformer type transducer is also designed here, which can be installed together with the magnetic bearing. The experiment of the displacement sensor is carried out.

Synthesis and Magnetic Properties of Nanocrystal Barium Ferrite by Glycine-nitrate Process

　　Synthesis and Magnetic Properties of Nanocrystal Barium Ferrite by Glycine-nitrate Process
　　Barium ferrite is a Permanent magnetic material with high magnetic anisotropy, high coercivity and excellent chemical stability, so it been widely used as permanent magnet, magnetic recording materials,tape and disk,high-performance nano-Ferrite absorbing agent. The micro-structure has great influence on magnetic properties for barium ferrite, when the particle size of barium ferrite reached its single-domain critical dimensions, the coercivity reached the maximum value. In order to obtain barium ferrite with small size and good single phase, various preparation methods had been developed in recent years, for example: ceramics, chemical co-precipitation Neodymium Magnets method, sol-gel method, hydrothermal method and so on,The purpose of these preparation methods is to obtain the nano-sized barium ferrite under low sintering temperature, which could improve the magnetic properties of the permanent magnetic materials.The glycine - nitrate combustion method has been widely used to prepare materials of fuel cells, however, the preparation of nano-crystalline barium ferrite with glycine - nitrate combustion method has been reported hardly. First, the resulted powders with glycine - nitrate process dispersion, single crystallinity, narrow particle size distribution, and high purity; Secondly, the glycine - nitrate combustion method is easy to operate with short experimental period, because the reactants dispersed uniformly in the solutions, the atom could enter the lattice sites through short-proliferation or http://www.999magnet.com/products/110-sintered-neodymium-magnets  rearrangement, the fast react speed and low formation temperature of glycine - nitrate combustion method resulted in small particle size and uniform distribution, which were advantages of the sol-gel technology and low-temperature combustion synthesis technology respectivly. The purpose of this work is to prepare nano-fuel Barium ferrite particles: with glycine nitrate combustion method. Glycine works as a complexing agent of barium ferrite , in order to have better magnetic properties of samples, and get good single phase.
　　The calcination temperature, metal ions ratio, holding time, glycine and the ratio of four metal ions were(1) The optimal stoiehiometry of metal ion (Fe/Ba )= 10.8.Antlfemimagnetie BaFe2O4 can be found in the sample with less iron, the coereiveforce of barium ferrite increased,.which can be explained by the pitining effect of BaFe2O4. BaFe2O4 and a-Fe2O3 can be found in the sample with more iron, the coereiveforce of barium ferrite decreased.(2). The optimal reaction temperature is 850℃.The resultant magnetic parameters of barium ferrite are Hc =5102Oe, Ms = 53.72emu/g,and the grain size is about 80-150nm;When the calcined temperature reached 950℃, the grain size is about 200-600 nm;and the coercive force decrease due to the formation of multidomain. The resultant magnetic parameters of barium ferrite are Hc = 4992Oe, http://www.999magnet.com/products/110-sintered-neodymium-magnets Ms = 54.72emu/g, and the grain size is about 80-150nm.(3) The optimal holding time of heat treatment is four hours. Intermediate phases were observed when the holding time is less than four hours,Longer holding time will give an increase of the grain size and a decrease of the coercivity.(4) The optimal stoiehiometry of (G/N) is G/N = 3.5. when G/N = 2, the actual temperature of combustion is too low, a-Fe2O3 is generated at this low temperature, so pure barium ferrite phase is generated difficultly .When G / N = 2.5, G/N = 3, the magnetic parameters of barium ferrite dose not reach the best value. With grain size increasing, and larger than single-domain critical size, magnetic properties also increase. When G/N = 3.5, the grain size is in single-domain and is larger than the critical size, coercivity reached the maximum value .When G/N = 4,the grain size is about 300-600 nm, and the coereive force deerease due to the formation of multidomain.

Research on Driving and Swimming Characteristic of A Capsule Micro Robot

　　Research on Driving and Swimming Characteristic of A Capsule Micro Robot
　　Micro robot features with small volume, quick response, and low energy consumption, which has extensive application. Such as wireless micro in-pipe swimming robot controlled by external magnetic field has a widespread prospect for applying in medical engineering, it has the characteristic of minor injury, painless and low treatment cost.This paper proposes a wireless driving method to actuate the capsule micro robot to swim neodymium standard state by using a permanent magnetic hollow cylinder of NdFeB magnetized in the radial direction as the exterior driver, which is rotated by a frequency conversion govern motor that produces a rotating external magnetic field, the micro robot has a spiral structure and a permanent magnetic inner driver of NdFeB embedded in it, the inner driver has the same magnetic structure with the exterior driver.On the basis of expatiating on the driving and the swimming theory of the micro robot, The paper firstly establishes the mathematics model of the magnetic driving torque and the axial magnetic force acted on the micro robot by the external magnetic field, makes a lot of calculations and analysis on the driving characteristic of the external magnetic field, and optimizes the pole number of the inner and the exterior driver.
　　Thereafter, the paper establishes the mathematical model of the axial thrust force, the load torque and the swimming velocity of the micro robot when it is swimming in the viscous fluid, and also establishes the simulative dynamic swimming model under the MATLAB environment of the micro robot. On the basis of theses models, the paper makes a lot of calculations, simulations and analysis on the stationary state and the transition http://www.999magnet.com/products/112-neodymium-standard-state state characteristic of the micro robot, and also optimizes the spiral angle of the micro robot.Finally, A lot of experiments on the driving and swimming characteristic were done. The results shows that the external rotating magnetic field produced by the NdFeB exterior driver could act a large magnetic drive torque on the micro robot, and drive it to double swim in the pipe full of viscous fluid with a quick velocity, the swimming velocity could be adjusted easily in a wide range by changing the driving frequency. The experimental results catch the theoretical results well, the driving method the paper proposes is feasible, and provides the basis for micro robot applying in medical engineering.

Study on Asynchronous Motor with Double Rotor

　　Study on Asynchronous Motor with Double Rotor
　　Asynchronous motor is widely applied, because of its simple structure, easy making, robustness, easy servicing, and convenient use. It accounts for over 85 percent of total electric rotating machinery. Asynchronous motor, which is a primary load of power system, consumes the most national generated energy, about 60 to 70 percent. So designing a new type of motor which can save energy and improve economic benefit has great significance. For this purpose, the paper put forth a new type of motor——asynchronous magnetic materials motor with double rotor.Firstly, this paper introduces the designing idea, basic structure, working principle and characteristics of the asynchronous motor with double rotor. Secondly, considering every part of the motor as a magnetic conductor element, we can get the Magnetic Equivalent Circuit Network Model (MECNM) of asynchronous motor with double rotor by the method of Magnetic Equivalent Circuit, and do analysis and calculation on this model. Thirdly, this paper introduces the method of calculating the electromagnetic field by using finite element method, and it analyzes the distribution of magnetic field in Asynchronous motor with Double Rotor in detail with the help of the http://www.999magnet.com software of ANSYS, then the dimension of permanent magnet has been obtained by simulation.Finally, after the experimentation, we can get the parameters of the asynchronous motor with double rotor. And comparing with ordinary asynchronous motor, this new type of motor has higher efficiency and power factor obviously. So it is a kind of ideal asynchronous motor of high efficiency and energy saving.

Optimization Design of Configuration and Drive Control for AC-DC Magnetic Bearings

　　Optimization Design of Configuration and Drive Control for AC-DC Magnetic Bearings
　　A magnetic bearing is the novel high performance, non-contact bearing, and its rotor is suspended in space by magnetic forces. The magnetic bearing has the advantages of no abrasion, no need of lubrication and seal, high speed, and long life, which has innovated the traditional supporting forms fundamentally. In the dissertation, a novel AC-DC 3 degrees Neodymium Magnets of freedom hybrid magnetic bearing (HMB) is proposed, which is driven by DC in axial direction and by a three-phase power converter in 2 radial directions respectively, and the permanent magnet provides the axial and radial biased magnetic flux, the structure of the stator and rotor with cone-shaped faces realizes control in 3 degrees of freedom using the same air gap.In the dissertation, based on the support of National Natural Science Foundation of China, optimal design and basic theory of AC-DC 3 degrees of freedom HMB are studied, the power driving system and digital control system of AC 2 degrees of freedom HMB is researched. The detail contents are as follows:Firstly, the structures and magnetic circuits of two AC-DC 3 degrees of freedom HMB are analyzed. Basic structure and suspending force principle of AC-DC 3 degrees of http://www.999magnet.com/products/110-sintered-neodymium-magnets  freedom HMB with cone-shaped stator and rotor have mainly studied, the mathematics models of magnetic suspension forces are deduced using equivalent magnetic circuit.
　　The coupling characteristics of movement and magnetic circuit between radial and axial are calculated and analyzed with MATLAB toolbox.Secondly, based on mathematics models and technical specifications given in advance, structure parameters of AC-DC 3 degrees of freedom HMB with cone-shaped stator and rotor are designed. Optimization design of structure parameters, simulation analysis of magnetic circuit and rationality of magnetic bearing’s structure are studied using finite element analysis software ANSOFT.Finally, power driving circuits of AC 2 degrees of freedom HMB is designed. Hardware structure and design process of power driving circuits are given in detail. Hardware structure and the implementation of control algorithms of AC 2 degrees of freedom HMB digital control system based on TMS320F2812 DSP are shown. The experimental results are presented.

无刷直流电机转矩脉动抑制技术的研究

　　无刷直流电机转矩脉动抑制技术的研究
　　With the rapid development of micro-electronics and electromotor technology, Brushless DC motor as a new type motor is becoming more and more popular in recent years. By means of power electronics circuit to control over commutation instead of traditional mechanical methods, Brushless DC motor which not only has the merits of the AC induction motor of reliable operation, simple structure and easy upholding but also has the merit of the DC motor high running efficiency, good timing performance, nice control characteristic and without wasting excitation, has applied widely in many Neodymium Magnets scopes.However, the problems such as rotor position estimation and the torque ripples have become the obstacles for the BLDCM to be used in high precision fields.
　　The objective of this dissertation is to minimize the torque ripple of BLDCM. Begin with the dissertation introducing the base elements, working principle, operating characteristic and transfer function of the Brushless DC motor, then it presents the disadvantages of sensor control. For detail, the principle and methods of sensorless control technology. On the base of these, the dissertation analyses the torque ripple in BLDCM with ideal trapezoidal waveform BEMF and compare with various detection http://www.999magnet.com/products/110-sintered-neodymium-magnets technologies of sensorless position, then it chooses Back EMF zero-detecting to design the system of sensorless Brushless DC motor control using the AT89C2051 chip. In addition, according to the factual require, the dissertation discusses in detail the questions of how to start, exchange phase and minimize the torque ripple at the condition of sensorless. Then it designs the system of hardware, software correspondingly.The brushless DC motor is modeled by using MATLAB/Simulink for experimental use to verify the validities of the proposed methods. Those are strongly supported by Simulink and experimental results, and achieve its aim and require, and can satisfy us.

Research of Wind Generation Simulation Experiment Platform Based on Adaptive Control

　　Research of Wind Generation Simulation Experiment Platform Based on Adaptive Control
　　It’s well known that energy has been a critical problem that restrict economic development of all countries.Human must find a sustainable path for energy problem from a long term.The key of sustainable energy is sustainable.In this situation Wind Generation became a important path for solving energy problem.The thesis mainly research brushless doubly fed wind(BDFM) and brushless doubly fed wind generation (BDFWG) System.The magnetic materials paper unifies the domestic and overseas related regulations and the literature to discuss the control strategy of BDFM and BDFWG..Based on energy situation of all countries in the world,We deeply know the importance of renewable energy including wind energy.Based on analysising the characteristic of structure,the principle and development history of BDFM.We researched four operations about BDFM. asynchronous mode of operation,synchronous modes of operation,double-fed modes of operation and generator mode of operation.Based on d-q coordinates we derivated the BDFM’s dynamic equation,electrical torque equation and mechanical movement equation.At last we researched control strategies about BDFM Field Orientation Control and Direct Torque ControlResearched two simulations about wind turbine rotor-dynamic simulation and static simulation And discussed three prime motors in the simulation system-DC Motor,http://www.999magnet.com Permanent Magnet Synchronous Motor and Asynchronous Motor.Developed a novel wind turbine simulation and designed a whole wind power generator system with BDFM including upper machine,simulator system and generator system,and did some experiment.
　　Comprehensive analysised the modern control theroy application in BDFWG,mainly including four modern control theory-optimal Control, H_∞control,sliding mode control and intelligent control.We developed a novel mathetic model of decoupled power.Because of disadvantage of PID control,we designed decoupled power control of wind gneration based on auto disturbance rejection control(ADRC).The correct and feasibility of result was identifiedBased on the basic structure and design of Model ReferenceAdaptive Control and mathetic model of decoupled power Lindear Model Following Control (LMFC)-PI control was designed.We analysised LMFC-PI controller by computer simulation.

Control System Research of BLDCM Based on the DSP

　　Control System Research of BLDCM Based on the DSP
　　The operating principle of PM BLDCM(Permanent-Magnet Brushless DC Motor) is analysed in this paper and the timing system of it is implemented as the experiment platform. In hardware design,the DSP TMS320LF2407 is adopted as the microprocessor and the IPM(intelligent power module) as invertor ,which is constructed compactly and works well.The neodymium standard state software of the system is designed properly ,in which little system resources is occupied, many functions are realised such as PWM output, signal sample of current and speed loop, and normal-reverse transfer. The double-loops system are adopted in the control system based on the DSP, hardware designs are completed ,including the three-phase inverter,the driving cirruit,the protection circuit,the position detecting circuit,the current detecting circuit and the periphery circuit of DSP.The software is designed to realize the control strategy,which includes the main,A/D sampling,current regulation,speed calculation,speed regulation and capture interruption subroutine.At http://www.999magnet.com/products/112-neodymium-standard-state last ,the experimental research is implemented on this BLDCM control system, and the waves of current and speed is given,the result is reasonable,which indicates the reliability of the design. In conclusion, the control scheme is proved to be feasible and reliable in this paper and a high performance is verified.

Study on the Preparation and Polishing Performance of Bonded Magnetic Abrasive

　　Study on the Preparation and Polishing Performance of Bonded Magnetic Abrasive
　　Magnetic Abrasive Finishing (MAF) is a new kind finishing method by the magnetic field acting on magnetic abrasives. In the process of lapping, the magnetic abrasives between tool and machining surface are flexible and can be controlled easily. Due to its advantages, this method has been successfully used to finish the mould curved surface, inner surface of stainless-steel air bottle etc. In view of the wear of magnetic abrasives, they should be refreshed necessarily and frequently. So, the abrasives with better performance and lower price have been one key factor to magnetic materials determine the machining effect. Although much research has been done on MAF, magnetic abrasive has not been commercialized yet so far, which greatly restricts the development of MAF. Aiming to solve above problem, we investigated the development of magnetic abrasive and its machining performance.Firstly, by analyzing the methods of making magnetic abrasives, for the sake of low cost and easy production, binding method was chosen as the research method to make magnetic abrasive. According to the performance requests of magnetic abrasive, binding principle and the process of binding, one technological process of mixing, binding, pressing, crushing and filtering was drew out. Then, Fe+Al2O3 and Fe+SiC bonded magnetic abrasives were made respectively. Finally, the experiments were constructed to compare the polishing effect of the above abrasives. The results indicate that both abrasives have fine machining performances.
　　However, Fe+Al2O3 abrasives are better than Fe+SiC ones on the aspect of improving surface roughness and http://www.999magnet.com duration. And the surfaces with Ra0.1μm around can be obtained.On the other hand, in order to improve the surface quality and shape precision of mould curved surface, NC magnetic abrasive finishing method of 2D curved surface was presented based on the honing principle. Then, simple polishing tool with permanent magnets embedding in the tool body and CNC machining program soft was also designed. The experiment results present the fine polishing effect with this method. This study is expected to be helpful to improve the efficiency of finishing process, reduce worker’s labor intensity, realize the effective control of finishing process and obtain fine quality of workpiece surface.