Control of Electrical Drives

Abstract

A wide range of equipment for welding and renewal production of general and special purpose is considered. The analysis of the use of electric drives in the equipment for arc mechanized welding and surfacing is carried out. The trends for the use of equipment of modern types are indicated, such as: automatic and semiautomatic machines. Based on the carried out analysis of the main representatives of these types of techniques, the directions for their improvement and the requirements for elaboration of the operation modes for the motors, which ensure the implementation of the production, installation of correction movements of the welding systems are formulated. It is determined, that in order to control and ensure the implementation of these movements, a wide range of electric drives of both direct and alternating current is used. In particular, for all linear displacements of the welding equipment, some relatively simple constructions of electric drives are used, which are based on electric motors of direct current. It is noted that the use of collector motors of low power (up to 100 W) in the electric drives due to the choice of feedback structures makes it possible to regulate the range at least 1:10 with rigidity of mechanical characteristics β≥5% in the whole range of regulation. The estimation of the properties of thyristor and transistor electric drives based on simple constructions for operation of welding equipment systems is given implementing traditional technologies for welding and surfacing. It is noted that the asynchronous frequency-regulated electric drive is widely used at present, mainly in the development of welding and surfacing systems of complex structures. The basic directions of step and brushless DC electric drives use are formulated. The investigations of the pulse mode of the vector-controlled synchronous electric drive carried out by mathematical modeling and simulation proved the possibility of its application in technological processes providing high-dynamic modes for mechanized and automatic arc welding.

Drilling Systems: Stability and Hidden Oscillations

“…Consider the equations of the induction motor to be the equations of the electromechanical model of the drilling system, (see Appendix 4, ; as well as other sorts of induction motors (Leonhard, 2001;Khalil and Grizzle, 2002; PI; PV) may also be considered) supplemented with the resistance torque M f :…”

“…The classic derivation of expressions for the currents in rotor winding and the electromagnetic torque of induction motor are based on the following simplifying assumptions (Popescu, 2000;Leonhard, 2001;Skubov and Khodzhaev, 2008): I It is assumed that the magnetic permeability of the stator and rotor iron is equal to infinity. This assumption makes it possible to use the principle of superposition for the determination of the magnetic field, generated by the stator;…”

“…Note that non-singular change of variables (4), makes it possible to reduce system (49) to the model used in (5) 1 . 1 Some other types of induction motors may also be reduced to this model under certain additional assumptions (Leonhard, 2001;Khalil and Grizzle, 2002) APPENDIX 5…”

DC/DC Converter for Motor Drive—Concept, Design, and Feed-Forward Control

“…This concept is useful when a small capacitor is used. The standard model DC motor [7,9] with constant field flux, which can be assumed, if a permanent magnet is employed, or a constant excitation is used…”

Using Hamiltonians to Model Saturation in Space Vector Representations of AC Electrical Machines

“…In the (α, β) frame (total power invariant transformation), the usual dynamic equations read (see, e.g., [2,4]):…”