SU1591160A1

SU1591160A1 - A.c.to a.c.voltage converter

Info

Publication number: SU1591160A1
Application number: SU884443928A
Authority: SU
Inventors: Aleksandr K Mukonin
Original assignee: Voronezh Polt I
Priority date: 1988-06-21
Filing date: 1988-06-21
Publication date: 1990-09-07

Description

The invention relates to a converter technique, in particular to

devices for converting energies of alternating voltage with fixed values of voltage and frequency into electric energy with adjustable values of voltage and current. The purpose of the invention is to simplify the device. The device contains a three-phase mains transformer 1 with a neutral wire, the windings of which are connected to a thyristor inverter 11 and a diode rectifier 2 connected according to the zero circuit. AC diagonal bridge inverter transistors

7-10 is connected to the downstream terminals and cathodes of the respective diodes 16, 17. The anodes of the above-mentioned diodes are connected to the combined cathodes of thyristors 12-14, which are driven by a network of inverter 11, which makes it possible to halve the number of diodes of the output bridge inverter.

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The invention relates to converting technology, in particular to devices for converting energy of alternating voltage with fixed values of voltage and frequency into electric energy with adjustable voltage and current, can mainly be used in controlled electric drives. ten

The purpose of the invention is to simplify the converter.

FIG. 1 shows the scheme of the proposed converter; in fig. 2 diagram of the switch key management system; 15; in fig. 3 - characteristics of the input-output relay element; in fig. 4 - diagrams illustrating the operation of the converter.

The converter (Fig. 1) contains 20 AC supply mains with a zero drive, which is used as a three-phase ¹ transformer 1. A diode rectifier 2 is connected to the supply mains, each being made according to 25 zero circuits on diodes 3-5. Conversion. ”· The user also contains a load of 6, an output inverter on transistors.

7-10, a network-driven, inverter 11, made on thyristors 12-14, with a thyristors control unit 15, made according to the zero circuit, and diodes 16 and 17 connected between the input of the slave network inverter 11 and one of the corresponding load terminals 6. 35

Threshold sensors 18 and 19 are included between the neutral wire of the transformer 1 and the two controlled keys of the inverter.

The control circuit, keys 7-10, includes an adder 20 (Fig. 1) connected to the outputs of sensors 18 and 19, an adder 21, a relay element 22, a threshold element 23, logic elements AND 24 and 25, logic elements 45 NOT 26 and 27. The output signals and ^ _d - 0 ^ 4 of this scheme are control signals for the keys 7-10. · The input of the load current reference signal ί ₂ and the feedback signal on the load current 1 _0s , taken from the output, are sent to the input of the adder 21 · Adder 20.

The Converter operates as follows.

The three-phase system of sinusoidal voltages DC, 11 ^, and _the frequency CO (Fig. 4a) is removed from the output of the transformer 1, and the voltage and (Fig. 4e) _{from the} frequency CO. Unlocking

signals are fed to each of the thyristors 12-14 during 2 ^ / 3 periods of the supply voltage in the time intervals corresponding to the inverter mode of operation of the thyristors (Fig. 46, d), i.e. on the thyristor 14 a trigger pulse is applied in the interval 7 / 2-7 7/6, on the thyristor 12 - in the interval 77 / 6-1 ΐ7 / 6, on the thyristor 13 - in the intervals 0-7 / 2,117 / 6-2 7.

The plots in FIG. 4d illustrate the operation of a converter with a control circuit made in accordance with FIG. 2, in the case when the signal _{3 is} positive. At the same time at the output of the element 23 logical "1", at the output of the element 27 'logical "0". the keys 8 and 9 are open (locked), the key 10 is closed and the load current формирование is formed by switching the key 7.

In the time interval, for example,

Sleep output member 22 "1", the output member 24 is also "1", the switch 7 is closed and the current in the load ί _n under the influence of the voltage rectifier and increases _in L1 and flowing through the switches 7,10 and 19. In this case, shunt feedback signal communication current ί ₀₀ proportional to the current also increases. The output of the adder 21 decreases and * Currently Sdostigaet threshold relay element at the output of the relay member 22 appears "O", switch 7 is opened and the load current begins to subside under the influence ϋ ₀ voltage flowing through thyristor 13, diode 16, transistor 10 and shunt 19. At the same time, the signal increases, at the moment of time it reaches the threshold of the relay element, at the output of elements 22 and 24, "T" appears, the key 7 closes, the current ϊ _Η starts to increase, etc.

Thus, a current is formed, the average value of which is proportional to the reference signal заданияρ

When a negative reference signal at the output of the element 23 "O", the keys 7 and 10 are open, the key 9 is closed and the formation of the load current is carried out by switching the key 8.

Claims

Claim

1. AC-to-AC converter containing a three-phase mains transformer to secondary windings connected in

1591160

the star, which is connected to the thyristors of the slave inverter network and the anodes of the diodes, a rectifier, and bridged transistor inverter is connected between their combined cathodes and the zero point of the star windings; , characterized in that, for the purpose of flattening, the anodes of the above-mentioned diodes are connected to the integrated cathodes of the thyristors driven by the inverter network.

I

2. The converter according to claim 1, in which each * transistor inverter arm, connected to the zero point of the transformer windings, includes input threshold current sensors connected to the transistor inverter control unit.