電氣工程專業(yè)畢業(yè)設(shè)計外文翻譯共27頁

1、精選優(yōu)質(zhì)文檔-----傾情為你奉上專心---專注---專業(yè)外文翻譯EnglishControl of Induction Machine Drives6.1 Introduction6.2 Scalar Induction Machine Control6.3 Vector Control of Induction MachinesVector Formulation of the Induction Machine?Induct

2、ion Machine Dynamic Model?Field-Oriented Control of the Induction Machine?Direct Torque Control of the Induction Machine6.4 Summary6.1 IntroductionInduction machines have become the staple for electromechanical energy

3、conversion in today’s industry; they are used more often than all other types of motors combined. Several factors have made them the machine of choice for industrial applications vs. DC machines, including their ruggedne

4、ss, reliability, and low maintenance [1, 2]. The cage-induction machine is simple to manufacture, with no rotor windings or commutator for external rotor connection. There are no brushes to replace because of wear, and n

5、o brush arcing to prevent the machine from being used in volatile environments. The induction machine has a higher power density, greater maximum speed, and lower rotor inertia than the DC machine. The induction machine

6、has one significant disadvantage with regard to torque control as compared with the DC machine. The torque production of a given machine is related to the cross-product of the stator and rotor flux-linkage vectors [3–5].

7、 If the rotor and stator flux linkages are held orthogonal to one another, the electrical torque of the machine can be controlled by adjusting either the rotor or stator flux-linkage 精選優(yōu)質(zhì)文檔-----傾情為你奉上專心---專注---專業(yè)reactanc

8、e are and , respectively. The referred rotor series resistance and leakage 1 R 1 Xreactance are and , respectively. The magnetizing reactance is ; the core loss 2 R 2 X m Xdue to eddy currents and the hysteresis of t

9、he iron core is represented by the shunt resistance . The machine slip s is defined as [1] (11.1) c R（6- 1)e res ? ??? ?where is the synchronous, or excitation frequency, and is the machine e ? r ?shaft speed, both in

10、 electrical radians-per-second. The power supplied to the machine shaft can be expressed as（6- 2)22 21shafts P R i s? ?Solving for and using Eq. (11.2), the shaft torque can be expressed as 2 i（6- 3) ? ? ? ?222 2 21 2 1

11、23| | ineeV R s TsR R s X X ?? ? ? ? ? ? ? ?where the numeral 3 in the numerator is used to include the torque from all three phases. This expression makes clear that induction machine torque control is possible by varyi

12、ng the magnitude of the applied stator voltage. The normalized torque vs. slip curves for a typical induction machine corresponding to various stator voltage magnitudes are shown in Fig. 11.2. Speed control is accomplish

13、ed by adjusting the input voltage until the machine torque for a given slip matches the load torque. However, the developed torque decreases as the square of the input voltage, but the rotor current decreases linearly wi

14、th the input voltage. This operation is inefficient and requires that the load torque decrease with decreasing machine speed to prevent overheating [1, 2]. In addition, the breakdown torque of the machine decreases as th

15、e square of the input voltage. Fans and pumps are appropriate loads for this type of speed control because the torque required to drive them varies linearly or quadratically with their speed. Linearization of Eq. (11.3)