*111592*

Технические науки / 5. Энергетика

N.V. Makarenko, O.O. Kostrov

Karaganda State Technical University, Kazakhstan

FEATURES OF THE MOUNTAIN thyristor DC motor

FOR ELECTRIC POWER SUPPLY FROM SOURCES commensurable capacity

Operating experience of thyristor DC (TDCM) on drilling rigs, excavators and other mining equipment has shown that its dynamic and static characteristics are strongly influenced by the internal parameters of the power supply, power lines and non-linear characteristics of the controlled rectifier [1-3].

At the same time power production equipment under consideration, as a rule, from the autonomous and nonautonomous sources of power commensurate with the capacity of electric mining equipment. For such an environment characterized by a significant (40 %) change in amplitude of the ac voltage and frequency fluctuations substantial mains (with electricity from an independent source), which leads to deformation of the static and dynamic characteristics of the actuator, as well as to false tripping, work related to the violation of the pulse and phase control [1].

In [3] examined the specificity of the reverse thyristor dc electric drilling rigs in operation, usually in terms of power supply from sources comparable power (SCP). As implemented in this regenerative mode the current in the motor armature circuit voltage depends on the network and determines the process of switching thyristors. In this case, the decrease in the voltage when operating as an inverter causes an increase in armature current and the angle of switching thyristors, which can lead to so-called «rollover» inverter, characterized by uncontrolled growth of current in the the electric drive power circuit.

To determine the dynamic properties of TDCM Fri for electricity from the SCP in the software environment MatLab-Simulink simulation model was developed that made it possible to obtain from simulations of the armature current waveform, and velocity (Figure 1), reflecting the start-up and static modes of operation at the rated voltage of the electric network, and configure regulators on the technical optimum (peregulirovanie current is less than 43 %). These characteristics are fundamental for the subsequent analysis of the results of simulation.

Figure 1. Depending on the armature current and motor speed at rated voltage network

The simulation results presented in Figure 2 represent transients in a TDCM Fri at maximum setpoint signal the automatic control system in a «soft» network.

Figure 2. Oscillograms of the armature current and speed of the actuator in a «soft» network

In the simulations the amplitude of the force varied in the range of voltage from the nominal value of up to 60 % of nominal at different angles of the thyristors unlock TV (angle α administration ranged from 1 to 80˚).

From the results of simulation experiments shows that the modes of the electric starter, and when its load unauthorized closing of the thyristors due to exceeding the value of the electromotive force of the motor armature rectified line voltage due to voltage drop in it, resulting in tripping the circuit. Thus thyristors are closed and the current sensor signal coming into the regulatory system is close to zero, which leads to a sharp increase in output speed controller. With the disappearance of the current in the armature circuit voltage starts to exceed the value of the electromotive force motor armature and thyristors, if the control action, open. Since the output voltage of the current regulator is very large, which in turn causes an increase in the armature electromotive force and the excess of its value over the value of the rectified line voltage. The latter leads to an unauthorized re-closure of the thyristors. The system enters the oscillatory regime. The frequency of oscillation is obviously determined by the inertial properties of the electric and the magnitude of the moment of resistance.

References:

1. Breido J., Makarenko N. Boundaries of D.C. electric drive stability at power supply from comparable power source // Materiály IV mezinarodni vědecko-praktická konference «Vědecke myslene inflacniho stoleti – 2008». Díl 10. Technické vědy: Praha. Publishing House «Education and Science" s.r.o. – S. 62-64.

2. Брейдо И.В., Эм Г.А. Исследование генераторных режимов тиристорного электропривода горных машин // Горное оборудование и электромеханика. – 2011. – № 3. – С. 25-31.

3. Парфенов Б.М., Кожаков О.И., Шиленков В.А. Электропривод буровых установок // Привод и управление. – 2001. – № 5. – С. 8-15.