Computer modeling of dynamics of regulated electric driver of water-resistant installation with PI regulator

Abstract

Water supply systems are energy-intensive objects, therefore, today, ensuring their energy-efficient work is a rather actual task. One of the promising trends in the field of energy saving technologies in recent years is the use of frequency controlled drives based on asynchronous short-circuited electric motors and semiconductor frequency converters, which reduce the consumption of electric energy, increase the degree of automation, convenience of operation of equipment and quality of technological processes.

Significant contribution to the development of the theory of frequency control was made by Epstein II, Zakladnii OM, Sandler AS, Sarbatov RS, who considered both static and dynamic operating modes of blood pressure in the supply of frequency converters (IF ) Scientists point out that nowadays, with priority of optimal design of asynchronous motors (AD), the tasks of optimal modeling of alternating current electric motors and determination of effective operating modes are taken into account.

In order to regulate the energy efficiency of the equipment of pumping stations, the optimum mode of operation of the pumps should be chosen for their joint operation. One of the ways to solve this problem is to change the frequency of rotation of the impeller wheel, which allows continuous control of pump performance with lower energy consumption.

The aim of the study. Construction of a computer model of the water supply system, for studying the dynamics of a regulated electric drive of a water pump unit with a PI regulator.

Materials and methods of research. For wide-range high-speed drives, you need to apply a vector control structure or direct torque control.

In the case of significant changes in the slip at the working section of the mechanical characteristics, in order to take into account electromagnetic transients, as well as at the start of the electric motor, models that implement the system of differential equations, which bind vectors of currents, voltages and flux couplings, represented in the coordinate system d, q, are used.

The system of these equations in the coordinate system d, q, which rotates with synchronous speed, in relative units has the form:

where the bases are taken as the nominal values of stator current I1n, synchronous speed 0n and frequency 1n of the supplied voltage. Output ratio:

where 0 - angular velocity of the stator field of the electric motor at a frequency 1 of the induced voltage, rad / s; L1, L2, Lm is the scattering inductance of the stator and rotor windings and the inductance of the circle of magnetization, Gn.

The vector of stator compression can be written as

Equations (1) are written in vector form in the form:

In the coordinate system d - q, which rotates with the speed of the stator field, system (3) is written as:

In implementing a vector mode of control of the rotational speed of an asynchronous motor, when ψ2 = const, the first four equations (4) in the operator form are written in the form:

When setting up, a significant current circuit error is allowed, since it is selected by the external speed loop.

The calculation of the circuit regulators of the main magnetic flux-coupling and speed is supplemented by an additional correction of the adjustments of the regulators to obtain a small override of the output value. Also introduced combined control with open loop control, correction of signals, reference models.

Transient processes during overloading or lifting of the load in the actuator PP-D with a doubly-integrating subordinate control system are characterized by the following transmitted function

To simulate, simulate and analyze dynamic systems, the interactive MATLAB Simulink tool is used.

Conclusions The results of the conducted research show that the introduction of the PI - regulator into the control system improves the quality parameters of the regulation process and reduces the static error, and also allows to save electrical energy, since the regulation proceeds according to the given technological parameters.