The author's abstract masters works on a theme: The substantiation of parameters and development of technical decisions in area is frequency - controlled the automated electric drive of submission of a clearing combine
The basic technological process of coal is reception of a useful mineral with the established parameters of quality.
Application of modern mine high-efficiency machines and mechanisms demands transition to regulation of the equipment in the automated modes with the purpose of maintenance of optimum operating conditions.
Systems of moving extracing machines are those elements automated management with which most expediently and is claimed.
A number of known experts in the field of mountain combine structures counts the most perspective subsystems moving clearing combine machines on a basis is frequency - adjustable the electric drive in view of operational development of domestic converting stations in hardened execution up to a necessary technological level.
The purpose and problems of work is development of mathematical model of the asynchronous engine at management of frequency and a voltage, also drawing up of transfer functions and the block diagram of the asynchronous engine at management in the above-stated parameters. Result of work will be the general block diagram of the electric motor together with the converter of frequency.
At research of transients in the asynchronous electric motor controlled by frequency and a pressure stator, it is convenient to use the system of coordinates rotating with speed, equal angular speed of rotation of the magnetic field, given to number of pairs the poles, equal to unit (given to the bipolar electric motor).
It is supposed thus fair equality
On the basis of the equations (6) for considered coordinate system it is possible to write down
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(7) |
For the full description of transients in the asynchronous electric motor to the equations of voltage and the moments it is necessary to add the equation
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(13) |
Having presented dependence of sliding of the electric motor on angular frequency of a voltage stator in increments and having executed liberalization provided that in working area, 
we shall receive
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(39) |
On the basis of the received expressions we shall make the block diagram asynchronous, the engine at management of angular frequency of a voltage stator and under condition of a constancy. However it is more convenient for making if to present coordinates of the engine in about R.u. having accepted for base values of coordinates of their value in a nominal mode: 
,
,
,where
- Synchronous angular speed of the engine. Then
,
,
,
,
.Transfer function (37) with the account (39) will be written down so:
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(41) |
The block diagram of the asynchronous electric motor at management of a voltage stator is shown in figure 1.
Figure 1.The block diagram of the asynchronous electric motor at management of a voltage stator is shown .
At research of dchanges the given parameters II circuits of the engine are resulted in parameters of an anchor circuit of the electric motor may be taken into discounted in circuit parameters . Alongside with it in structure TC of frequency there is the smoothing filter essentially influencing changes of system. According to the equivalent circuit of a circuit the rectifier - filter it is possible to write down the basic equations of changes of such circuit in increments of coordinates concerning initial values:
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(45) |
Assuming absence of influence on a target pressure of the inverter and neglecting Inertia an electromagnetic circuit of the electric motor it is possible to receive the general block diagram of the electric motor together with the converter of frequency (rice 3).
Figure 2. The general block diagram of the electric motor together with the converter of frequency.
Further will be submitted Animation graphic representations of direct start-up of the asynchronous electric drive, and it is frequency - controlled start-up of the asynchronous electric drive according to block diagrams above mentioned.
Figure 3. Animation the image of direct start-up of the asynchronous electric drive. (for viewing the image to press the button "to update" on the panel tool).
Figure 4. Animation the image frequency-controlled start-up of the asynchronous electric drive. (for viewing the image to press the button "to update" on the panel tool).
Apparently from graphic dependences submitted in figures 5,6 at various laws of regulation various values of the moment, currents, and frequencies of rotation turn out. Direct start-up is characteristic: currents in stator to a winding reaching 5-6. Variables and constant losses cause intensive heating the engine, first of all windings. The electromagnetic moment reaches 6 at start-up, influences windings and mechanical transfer. Time of action of these moments is rather insignificant, but nevertheless it promotes accumulation of deformations, reduction of a resource of system.
If to apply frequency regulation of the asynchronous electric drive at once it becomes visible as far as the starting moments and currents have decreased. And all this promotes reduction of losses, so also to increase of efficiency and. So the further work on modelling asynchronous it is frequency - adjustable drives should efficiency of all clearing combine as a whole is reduced to development of such model of regulation which would allow to increase maximum images efficiency of the electric drive, the engine.
