基于c8051f360單片機(jī)的電動(dòng)機(jī)微機(jī)保護(hù)畢業(yè)論文(參考版)
2025-06-30 17:02本頁面
【正文】 附錄Ⅰ 外文翻譯Induction motor [13]Electric motors convert electrical energy into mechanical motion and are broadly classified into two different categories： DC (Direct Current) and AC (Alternating Current). Within these categories are numerous types, each offering unique abilities that suit them well for specific applications. In most cases, regardless of type, electric motors consist of a stator (stationary field) and a rotor (the rotating field or armature) and operate through the interaction of magnetic flux and electric current to produce rotational speed and torque.Asynchronous AC motors, also known as AC induction motors (ACIM), are probably the most widely used motor of the day. Induction motors are simple, rugged, reliable and easytomanufacture. They include single and polyphase designs developing power levels from fractional to thousands of horsepower. ACIM includes squirrelcage and woundrotor induction designs. SquirrelCage_In squirrelcage motors, the rotor consists of permeable metal containing embedded strips of magnetic material. As the stator magnetic field rotates, the field interacts with the magnetic field established by the magnetic poles of the rotor, causing the rotor to turn at nearly the speed of the rotating stator magnetic field.WoundRotorIn woundrotor designs, the permanent magnets used in the squirrelcage motor are replaced by a rotor having windings. In this motor, when the stator magnetic field rotates and the rotor windings are shorted, the stator magnetic field motion induces a field into the woundrotor, once again causing the rotor to turn at nearly the speed of the rotating stator magnetic field. However, if the rotor windings are connected externally through slip rings on the shaft, the winding current can be controlled to increase or decrease the slip speed of the rotor.Principle of Operation of an Induction MachineThe basic principle of operation of an induction machine is illustrated by the revolvinghorseshoumagnet and copperdisk experiment pictured in the horseshou magnet is rotated, the moving magnetic field passing across the copper disk induces eddy currents in the disk. These eddy currents are in such a direction as to cause the disk to follow the rotation of the horseshoe magnet. With the direction of rotation shown in the figure, the eddy current will be as displayed in according to Fleming`s righthand rule. Rotation of a copper disk following the rotation of a permanent magnetFleming`s righthang rule： Place the thumb and the first and second fingers of the right hand so that all three are mutually the hand inthis position, the first finger is pionted in the direction of the field, the thumb is in the direction of motion of the conductor, and the second finger is in the direction of the induced voltage. Note that the relative motion of the conductor is opposite to the direction of the magnetic field.By applying Fleming`s lefthand rule, the force on the copper disk is determined to be in the direction of rotation of the magnet.Fleming`s lefthand rule： Place the thumb and the first and second fingers of the left hand so that all three are mutually perpendicular to each other. With the first finger in the direction of the field and the second finger in the direction of the current, the thumb indicates the direction of force.Whereas the copper disk will rotate in the samedirection as the rotating magnetic field, it will never reach the same speed as the rotating magnet, because if it did, there would be no relative motion between the two and therefore no current induced in the copper disk. The difference in speed between the rotating magnetic field anf the copper disk is known as slip, whith is essential to the operation of an induction induction motors the rotating magnetic field is set up by windings in the stator, and the induced currents are carried by conductors in the rotor. The rotating horseshoe msgnet and copper disk are considerably different in structure from today`s induction motor, but the basic principles of opetation are the same.The rotating magneting field is essential to the functioning of an induction motor. In practical machines this rotating magneting field is achieved by a bination of a space displacement of the windings and a time –place displacement of the exciting voltage.The rotor is formed form laminsted electrical steel punchings, and the rotor winding consis of bars contained in slots punched in the laminations. These bars are shortcircuited at both ends by a shortcircuiting ring. A barend ring structure, without the laminated core, is called a squirrel cage. In smalland mediumhorsepower sizes, rotors are msde by casting aluminum into the rotor core. In the larger sizes of ac motors, castaluminum rotors are not practical, and copper bars are inserted into the rotor slots. These copper bars are shortcircuited at both ends by a copper and ring, and the end ring is brazed or soldered onto the bronze or other alloys are used to replace copper in making the 。感謝山東科技大學(xué)這一培養(yǎng)人才的沃土，在此我不僅學(xué)到了專業(yè)理論知識(shí)，還學(xué)到了許多課本之外的許多知識(shí)。參考文獻(xiàn)[1]. MCS51/52單片機(jī)原理與實(shí)踐 [2]:中國電力出版社，1992[3]張宇輝編著. 電力系統(tǒng)微型計(jì)算機(jī)繼電保護(hù). 中國電力出版社[4]，2001, 29(10): 14[5]. 單片機(jī)應(yīng)用系統(tǒng)設(shè)計(jì)與產(chǎn)品開發(fā). 人民郵電出版社[6]，1998, 26(1): 17[7]陳皓，汪波，2000, 20(2)，32一36[8]，1998, (3): 3335[9]賀家禮，:中國電力出版社，1994[10]. Future Trends in Protective Relaying, Substation Automation,Testing and Related Standardization. In: Transmission and Distribution Conference and Exhibition 2002: Asia Pacific. IEEE/PES, 2002, 598一602[11]Jingxuan Hu, , Erwin Dirks. A Graphical Block Platform forRealTime DSPBased Digital Relay Development. In: International Conference on Power System Technology, 2002, 265269.致謝在導(dǎo)師的幫助下，我終于按時(shí)完成了我的畢業(yè)論文。本論文主要完成了以下工作：(1)以電動(dòng)機(jī)智能保護(hù)原理為理論基礎(chǔ)，結(jié)合裝置硬件部分的設(shè)計(jì)，對(duì)裝置的軟件部分進(jìn)行了簡(jiǎn)單的設(shè)計(jì)；(2)對(duì)有關(guān)的軟件流程進(jìn)行了編寫；(3)對(duì)系統(tǒng)中可能存在的干擾問題進(jìn)行了分析，并提出了硬件抗干擾的一些具體措施。在系統(tǒng)硬件設(shè)計(jì)過程中，可采取如下的措施,以提高系統(tǒng)的可靠性，增強(qiáng)
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1