Features and tendency of development of modern electric drive

Control elements

Power elements

Elements of automated electric drive

MODERN ELECTRIC DRIVE, ITS FEATURES AND TENDENCIES OF DEVELOPMENT

All ED elements are divided into 2 groups:

- power elements (through them the main energy flux is flowing);

- control elements (for converting, amplifying and control signal transmission, also these elements include protective, signalization and indication elements).

Electromachine voltage sources:

- generators;

- electromachine amplifiers;

Power converters (electromachine and static):

- converters of alternative voltage into direct one (adjustable and nonadjustable rectifiers);

- converters of direct voltage into alternative one (inverters);

- converters of direct voltage into direct one (pulse converters);

- converters of alternative voltage into alternative one (frequency converters at adjustable and nonadjustable frequency).

Electric motors:

- of direct current;

- of alternative current;

- step motors.

Electric apparatuses (contact and noncontact):

- contactors and magnetic starters;

- automatic switches;

- switches and commutators;

- fuses.

Elements of ED mechanical part:

- gears;

- converting links.

Electromagnetic clutches:

- with mechanical link;

- with link with electromagnetic field.

Electric apparatuses (contact and noncontact):

- switches and commutators;

- multipurpose commutators;

- control buttons;

- relays;

- controllers;

- fuses.

Transducers:

- of position;

- of speed;

- of current;

- of voltage;

- of the moment and so on.

Electric machines of automatic systems:

- power and executive motors;

- selsyns;

- tacho-generators;

- rotating transformers;

- electromechanical devices of hygroscopic systems.

Corrective elements (in direct and feedback channels to make the system with required dynamic features):

- proportional (R, potentiometer);

- inertial (RC, 1/RC,TG);

- differential (RC,TG).

Block control elements:

- analogue;

- digital;

- microprocessors;

- computers.

Individual automated ED now is widely used in all human activity fields.

Due to mentioned above features of Electrical Drive the improvements of its technical parameters in all application fields serves as the base of technical progress.

Field of ED application determines, primary, wide range of ED power efficiency (of thousand part or Wt to tens thousand kWt). For example, ED power efficiency of some medical probes and medical tools is only 0.003 Wt, and the ED power efficiency of rolling mills is above 10000kWt.

Unique in its power efficiency industrial equipment, such as:

- Steel-works rolling mills;

- Mining lifting machines;

- Excavators for mining industry;

- Heavy mounting and civil structuring machines;

- Heavy-duty metal cutting lathe and machining centers are equipped with superpower ED with applying of unique electrical machines, converters and controlling devices. Control devices provide wide possibility of flux regulation of electrical energy, which is supplied to electrical motor, for the purpose of coordinate regulation, controlling ED motion and parameters of production process.

ED controlling device is made-up on the base of electronics and microelectronics using. Modern control devices are mainly presented with microprocessors or computers.

ED serves as the base of complex mechanization and automatization. In modern hierarchy of controlling production processes ED takes the lower degree where generated at higher levels command signals are realized into displacement (mechanical motion) of actuators. Their automated operation predesigned into control system of ED through rigid and adaptive programs is included.

Therefore the physical features of ED, its regulative possibilities, especially in modern technologies are of the most importance.

One of the manufacturing problems is power supplying, and hence the ED consumption makes about 50 % of the total generated power, the problem to increase the ED efficiency is one of the main directions of its designing and operation.

Modern ED has such development trends:

The 1^st trend. To wide fields of applying of regulated ED in recent time at the expense of using AC ED with microprocessing control. Besides, new trends and fields of human activity widens up the field of application of special ED (home appliances, mastering world ocean and others).

The 2^nd trend. Improvements of ED is connected with scientific-technical progress particularly the achievements in materials science and microelectronics. Development of new types of ED, AC ED in particular.

The 3rd trend. Raising of technical requirements to dynamic and accuracy characteristics of ED, expansion and elaboration of ED functions, particularly connected with production process controlling.

The 4^th trend. Raising of automatization level induce the creation of robots, manipulators, flexible transfer lines and manufacturing.

The 5^th trend. Unification of ED element basis, designing of complete ED on a base of module-blocked principle, microprocessor ED.

The 6^th trend. Simplification of ED mechanical part, simplification of its kinematic links by improvement of regulative functions directly of electric machines converter. Designing of linear and backward-translatory non-rotational electric machines. Constructional incorporation of a motor and executive mechanism. Mounting of electric motor into mechanical construction of mechanism and other.

Дата добавления: 2014-01-05