SU655060A1 - Method of arresting induction power-diode generator - Google Patents

Description

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The invention relates to electrochemical inertia technology and can be used for frequency-controlled electrical circuits and asynchronous valve generators with voltage from a thyristor frequency driver.

There is a known method of switching off the asynchronous valve ventilator geyirator (Ablj, for example, in avarin regimes and during overloads, which reduces to the disconnection of reactive power from the ICU and the excitation of ABi by switching with auxiliary contactors in the stator circuit of the ABG from a thyristor source of reactive power (iiijeAlj).

The disadvantages of this siocoBa are in reduced reliability due to the switching overvoltages of the TIRM valves when the generator power circuits break and in the low response of the co-tacts.

The most technical solution to isoorethenia by its technical nature and the solving task is the method of switching off the asynchronous valve generator by removing the control emulsions from the iilHAl main thyristors ./ ;.

However, this method is implemented in TIRM only with the presence of omnipotent thyristors, which complicates AVH and reduces its reliability.

In addition, the dainy method does not eliminate the drawback, connect it with the commu- nication and reprogramming the 1IRM gates, and therefore; as a result, also has reduced reliability.

The purpose of this invention is to increase reliability by eliminating switching switching and breaking of the power supply system during the excitation of a geerator.

This goal is achieved by the fact that in order to disconnect AB1, Viachale increases the frequency and the switching off of the thyristors of the source of reactive power until the value of the current through the thyristors is lower than the holding current, and then the control pulses are removed from the indicated source of reactive power.

The invention is illustrated in drawings, where in FIG. 1 shows the electrical circuit diagram of the geierator, and FIG. 2 - time diagrams of the device rotots on a detailed basis.

An asynchronous fan generator consists of an asynchronous machine with a squirrel-cage rotor 1 (Fig. 1), a thyristor source of reactive power 2 with an input capacitance Cf, an AUGH control circuit, consisting of a control circuit 1IRM 3, a correction link 4, a voltage converter into frequency 5, block

Comparison 6, voltage adjuster 7, logic comparison circuit 8, voltage sensors 9 And current 10, battery I. The load of direct current is denoted Rn.

Consider the essence of the method of shutting down AVG in two characteristic modes: offline (without battery (AB), Fig. 2 a) and when operating in parallel with a battery (Fig. 26).

FIG. Fig. 2a shows diagrams of voltage variation of the asynchronous generator UAP, current through the thyristors of the reactive power source / thermometer, and the given law of variation of the frequency TIRM when the AUG is turned off without the battery 11.

Suppose, at the time instant j, the logic comparison circuit issued a signal to turn off the generator and the AGG excitation frequency began to increase with the help of the voltage generator 7 according to a predetermined law (Fig. 2a). As soon as the generator excitation frequency increases, the magnetisation current from TIRM decreases, then the output voltage of the asynchronous generator t / Ar decreases.

When the thyristor current TIRM decreases below the holding current (approximately 0, 3L), the TIRM de-energizes and shuts down, and AVH is released at the same time. At time 2, according to this method, control pulses are removed from TIRM and the shutdown process is completed.

FIG. 2 b are diagrams showing the shutdown of the AUG when working with the battery 11 connected in parallel with the load.

Assume that up to the time point i AVG provides the battery charge / charge current. As the driving frequency increases, the slip of the asynchronous machine becomes positive, which corresponds to its transition to the motor mode (s). In this case, the AB current changes its direction and becomes discharged. With growth

Frequency voltage and magnetization current from TIRM AVG decrease and by the time point 3 the current of the thyristors TIRM becomes lower than the holding current, therefore, after removing the TIRM control pulses, the generator is de-energized, the generator is completely de-energized. Thus, when shutting down the AUG by this method, there are no breaks in the power circuits in both TIRM and AUG, and

the process of switching and distribution of currents in the valves proceeds as in the normal operating mode, therefore, there are no sharp surge voltages and currents on the TIRM valves, which leads to an increase in reliability.

The advantage of this shutdown method is also that the stored energy of the filters or the AB during the shutdown is evenly distributed between the valves, which accelerates its dissipation.

The generator de-energization time is determined by the rate of increase in the frequency of TIRM and is a fraction of a second.

Claims (2)

Invention Formula Method of switching off an asynchronous valve generator with a thyristor source of reactive power by removing control pulses from a thyristor reactive power source, characterized in that, in order to increase reliability and eliminate switching overvoltages, first increase the switching frequency of the thyristors of the reactive power source to decrease the current through the thyristors below the restraint current, then remove the control pulses from the specified reactive power source. Sources of information taken into account during the examination 1. Patent of Germany No. 1563366, cl. 21C 64/50, 1974. 2. Patent of Germany No. 1288670, cl. 21C 59/10, 1971.