VII Международная студенческая научная конференция Студенческий научный форум - 2015

This paper deals with the study of transients of the system of current and speed control.

The diagram of system of the subordinate current, speed and tension control is presented on Figure 1.

Figure 1. Diagram of object control with regulators of current, speed and tension.

This diagram is applied when a mechanical constant of time Т_м is much more than electrical constant of time Т_1 .

where Т_1 – the amount of not balanced constants of time, i.e.

The PI-regulator (the proportional integrating regulator) is applied as the regulator of current.

Figure 2. Diagram of closed circuit of current

Tension from 0 to 10B goes to the input of the researched control object and, therefore, should meet the following requirements:

Therefore, it is necessary to adopt current sensor coefficient to meet the following equality:

Transfer function of the PI-regulator is

where – a time constant of regulator of the current:

– proportional part of the regulator of current:

Transfer function of an open circuit of current is:

Parameter is a modular optimum, it is defined as follows:

where – a index of oscillation , (is accepted equal to one for receiving zero overregulation)

Cutoff frequency is :

Coupling frequency is

The regulator of current is:

Simulation of a circuit of the current presented on Figure 3.

Figure 3. Simulation of circuit of current with regulator

The controlling influence submits Uy = 1B goes to the input.

Figure 4. Transfer characteristic of current circuit

Transfer function of an open current circuit is:

where - a time constant of current circuit,

Now, lets consider the issue of tuning of speed contour. The diagram of closed contour of speed is:

Figure 5. Diagram of a closed contour of speed with the contracted current circuit

We synthesize the regulator of speed of P-type (proportional):

Transfer function of an open contour of speed is:

Parameter is defined as follows:

where – a index of oscillation,

Total constant of time of a contour of speed is:

Cutoff frequency is:

Coupling frequency is:

The regulator of speed is the following:

The model of a closed contour of speed with the P-regulator is the following:

Figure 6. Simulation of a contour of speed with the P-regulator

In case of simulation of a contour of speed in the program SciLab we have the following transfer characteristic. The controlling influence Uy = 10 V goes to the input:

Figure 7. Transfer characteristic of a contour of speed

Transfer function of an open-ended contour of speed is:

where - a time constant of contour of the speed,

In conclusion, I’d like to say that next step is to study the transients of the system of tension control.

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