SU760351A1 - Single-phase inverter - Google Patents

Description

The invention relates to the field of converting technology, in particular to DC / AC converters.

The well-known autonomous inverter-5 ditch £ 1] schemes, containing, on the AC side, a transformer with tap-offs for step-by-step adjustment of the output voltage, do not allow for sufficiently high quality of the shape of the output voltage curve with deep control of its magnitude.

The known inverter is £ 2], which contains a bridge of main types (through the filter choke, connected to the input terminals) (5 resistors with the primary winding of the output transformer in the diagonal, from which soldering is connected to one electrodes of additional thyristors, the other electrodes of which are paired to 20 throttle.; · <.

The disadvantage of the known inverter is the presence of a large number of additional thyristors, since each group consists of three thyristors.

The aim of the invention is to reduce the number of thyristors. To accomplish this goal in single phase 30

2

an inverter containing a main thyristor bridge connected to the input terminals through a filter choke with a primary winding of the output transformer in the diagonal whose tapings are connected to one additional thyristor electrodes, the other electrodes of which are connected in pairs to the filter choke tapes of the transformer primary winding equal to the number of additional thyristors, the number of turns in the sections formed by each of these taps and the corresponding end of the transformer winding on * kovo.

The inverter circuit is shown in the drawing.

The inverter contains a bridge of primary thyristors 1-4 with the primary winding of transformer 5 at the output, a filter choke 6, to which the anode of the additional thyristors 7, 8 are connected, and their cathode - to a pair of taps of the primary winding of the transformer 5 connected to the secondary about ^! transformer coil battery capacitors 9, controlled compensating device 10,

h 760351 4

When several additional thyristor pairs are introduced into the Inverter circuit, the number of taps of the choke windings and the number of pairs of taps of the transformer primary winding is equal to the number of these thyristor pairs, and each additional pair of thyristors is turned on so that closer to the power supply terminal the tap of the choke coil is connected remotes from the extreme conclusions tapes .. the primary winding of the transformer. _ ' ⁰

The scheme works as follows.

Consider the operation of the circuit for the most common case when the regulation is carried out with the aim of stabilizing the output voltage using - L 5

power point range

When applying control pulses

thyristors 1-4 transformer transformation ratio is equal to · 20

• ha inductance throttle turns

mudflow is determined by the sum of turns (ν ₄ +

+ MD ·). If in this circuit you remove control pulses from thyristors 1, 2 and feed them respectively to thyristors 7, 8, then the transformer ratio will be injured

25

turns and during half-.

l

Period with open thyristors 7, 30

3 together with turns U ₂ in the work of the section-. VTS turns on the right, and for the next half-period with open thyristors 8, 4, along with turns M ₂ , the W-5KI on the left participate ^{in the} Work. The inductance of the choke in this case will be determined only by turns.

The change in the transformer coefficient / transformation in this case is 40

- is used as an auxiliary means for regulating the output voltage, and at the same time by this change is the change in the inductor inductance to maintain the inverter natural frequency of oscillation in order to improve the sinusoidal shape of the output voltage curve. G Suppose that the input voltage is equal to the maximum value and _ai , _ah

In this case, the control pulses are fed to thyristors 1-4. Reducing the input voltage from the value of C ^^ to maintain a constant value of the output voltage of the inverter produces an increase in the total reactive power on the AC side by reducing the reactive power. Noah power controlled compensating device 10. ·

When the input voltage reaches a value that is determined from the condition ΙΜα ^{101 1} , yn -,

^and <* < ^and 3t ·. "

'Equals pulses are removed from 1.2 and the thyristors are fed respectively to thyristors 7, 8. If the ratio between windings V * and V * selected based upppnnya' - _then

'^; · 4 ^ * 2 and _{a <} '

the transformation ratio of the transformer will increase at the same time as much (times, how much * voltage 'Less voltage, that is, when

In order to maintain the inverter output voltage constant, it will be necessary to reduce the total reactive power on the AC side to the value occurring at the input voltage and _am and operating thyristors 1, 2 by increasing the reactive power of the controlled compensation device 10.

With a further decrease in the input voltage from the value and,} /, to the value of maintaining constant

the output voltage of the inverter is produced by re-increasing the total reactive power on the AC side by a similar reduction in the reactive power of the controlled compensating device 10.

The ratio between turns ₄ and> windings of the choke is chosen so that when both thyristors 1, 2 and thyristors 7.8 are operated, the inductance of the choke has the same value given to the secondary winding of the transformer. This will ensure that the electromagnetic processes in the inverter are identical when both thyristors 1, 2 and thyristors 7, 8 are operating.

Claims (1)

Claim a single-phase inverter containing a main thyristor bridge connected to the input terminals through the filter choke with the primary winding of the output transformer in the diagonal, whose tapings are connected to one of the additional thyristors electrodes, the other electrodes of which are connected in pairs 50 to the chokes of the filter choke, different from y u and y-. With the fact that, in order to reduce the number of Thyristors, the primary winding of the transformer is made with a number. otpaek paray number of additional 55 thyristors, and the number of turns in the sections formed by each of these taps by the corresponding end of the winding of the transformer is the same. ;