SU1636833A1 - Method for controlling three-phase sine voltage stabilizer - Google Patents

Abstract

The invention relates to electrical engineering and can be used for narrow-band regulation or stabilization of three-phase sinusoidal voltage. The aim of the invention is to increase the power factor at the input of the stabilizer with a load. The achievement of the effect is due to the fact that the converter 2, used for rectification at the input or output of the stabilizer, consumes almost purely active current. This current, adding to the load current, decreases the phase shift between the current and the voltage on the stabilizer input. The output voltage of the stabilizer is obtained by summing the input voltage with the voltage generated by the inverter3. The voltage is stabilized by adjusting the phase of the output voltage of the inverter3 using the control system 4 as a function of the deviation of the output voltage from the setpoint from the specified level, 2 sludge. a s

Description

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. J Gul

The invention relates to electrical engineering, in particular, to converter technology, and can be used for narrow-band regulation or stabilization of three-phase voltage in power supply systems for industrial, agro-industrial, cultural and community facilities.

The purpose of the invention is to increase the power factor at the input of a stabilizer with a load, which ensures a reduction of the reactive power consumed by the stabilizer, which reduces the current consumption and reduces energy losses without installing additional devices, such as capacitor banks, to compensate for reactive power,

The stabilizer control method includes the operations of measuring the output voltage of the stabilizer, comparing it with the voltage of a given level, and generating a control signal from the resulting difference signal. The control signal changes the phase of the voltage at the output of the inverter, which converts the rectified input or output voltage of the stabilizer into a variable of the same frequency, but varying in phase depending on the control signal. The voltage from the output of the inverter is fed to the input of the volt- auxiliary unit.

FIG. 1 is a block diagram of a device implementing a method for controlling a three-phase sinusoidal voltage stabilizer; in fig. 2 - vector diagrams explaining the method of controlling the stabilizer of the three-phase sinusoidal voltage and the operation of the device implementing it.

The device contains a three-phase booster unit 1, which is a three-phase booster transformer and is connected between the input and output terminals of the stabilizer, the inverter 2 AC to DC, the input of which is connected to the output (or input) of the stabilizer, and the output is connected to the supply terminals Inverter 3. The inverter 3 control system 4, in which the formation of a signal controlling the phase of the output voltage of the inverter 3 is carried out, is connected to the output with its output

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16368334

inverter 5 input

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The stabilizer terminals are also connected to the input of the output voltage sensor 5, the output of which is connected to the first input of the comparison element 6, another input connected to the reference voltage source, and the output to the input of the control system 4. The primary winding 7 of the three-phase transformer booster unit 1 is connected to the output of the inverter 3, and the secondary winding 8 of the transformer is connected between the input and output terminals of the stabilizer.

The device works as follows

As the voltage 0 at the input increases (Fig. 2a) and, accordingly, Q increases at the output of the stabilizer, the signal at the output of the voltage sensor 5 increases, which leads to a decrease in the signal at the output of the reference element 6, which is fed to the input of the system 4 controlling the phase of the output voltage of the inverter 3. The phase change of the output voltage of the inverter 3, which is powered by the variable voltage converter 2 to a constant, occurs. Converter 2 consumes almost the number of active currents. This current 1, combined with the current l at the output of the stabilizer, shifts the resultant current 14 at the input (Fig. 2). The output voltage of the inverter 3 is supplied to the primary winding 7 of the transformer of the booster aggregate 1. In

As a result, the voltage Ut of the secondary winding 8 of the transformer of the booster unit 1, added to the voltage fUj at the input, reduces the voltage Od at the output of the stabilizer to the required level. In this case, as follows from FIG. 2, the angle between the voltage Uj and the current 14 at the input is less than the angle between the voltage 04 and the current i at the output, i.e. The device has the property of reactive power compensation and therefore allows an increase in the power factor. Similarly, the device operates (Fig. 2b) and when the input voltage drops below the required level.

Claims (1)

Formula of the invention The method of controlling the stabilizer of a three-phase sinusoidal voltage5 0 five 0 five It contains a three-phase volt-auxiliary unit connected between the input and output terminals, an alternating voltage converter into a constant output connected to the supply terminals of the inverter, the output of which is connected to the control input of the three-phase booster unit, which consists in measuring the output the voltage of the stabilizer, compare it at a voltage of a given level and form a difference signal, the control signal is formed from a passive signal, a distinctive figure. I 6833 In order to increase the power factor at the input of the stabilizer with a load, the inverter acts on a control signal by which the phase of the voltage at the output of the inverter is measured ahead of the input voltage of the stabilizer by the angle Ob, the phase shift angle is adjusted from 0 to fr rad, while using the specified alternating voltage converter to constant voltage, the output or input voltage of the stabilizer is rectified. ten / id6