SU1241382A1 - Self-excited inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in power supply systems. The purpose of the invention is the improvement of mass and mass indices. The device contains a transformer (t) 3 with a midpoint, controlled thyristors 6 and 7, switching capacitor 8. T 3 contains the main core (C) 17 and the control core 18, two primary working half windings 4 and 5 and output 19 are wound on C 17 and 18, and the control windings 13 and G4 on C 18. The planar control C 18 is located on C 17 in such a way that the average lengths coincide, while the core material has a rectangular hysteresis loop. The specified implementation of the magnetic circuit. Reduces the surge current key when switching. The introduction of the throttle 2 and the connection of the control windings to the negative input terminal allows to reduce the weight and dimensions of the device by providing a deep end of the magnetic circuit. I zp, 4 Il. (Oh I ate i ..

Description

 , 1,1

The invention relates to electrical engineering, namely to converter equipment, and can be used in power supply systems.

The purpose of the invention is to improve the overall dimensions of the device by providing deep saturation of the main magnetic circuit and improving reliability by reducing the current ejection of keys when switching

SRI.

FIG. 1 shows the electrical circuit of the inverter; in fig. 2 shows the placement of a flat control heart 1 |: and with two control windings on the transformer core; FIG. 3 is a section A-A in FIG. 2, in FIG. 4 - diagrams of the process of remag-. dropping of the main and controlling cores, where B is the induction in the core material, H is the magnetic field strength.

The inverter (Fig. 1) consists of a source of input voltage 1, the pole of which is connected via a smoothing choke 2 with the midpoint of transformer 3, the anodes of controlled thyristors 6 and 7 are connected to the primary semi-windings 4 and 5 of the latter, in parallel with which a switching capacitor is connected 8. The control electrodes of thyristors 6 and 7 are connected to control circuits for the generation of trigger pulses, including diodes 9 and 10 and resistors 11 and 12. Diode 9 is connected to resistor 12, and diodes 9 and 10 are connected to one end of windings 13 and 14 other ontsy which have a common point from actuated cathodes of thyristors 6 and 7 and connected to a minus power source 1. The thyristor control circuit; 6 includes an RC starting circuit for 1 day on a capacitor 15 and a resistor 16.

The output transformer 3 contains a main core 17 and a control core 18 (Fig. 2), two primary working windings 4 and 5, one output winding 19, two control windings 13 and 14.

It is of fundamental importance that both cores have a rectangular hysteresis loop (Fig. 3), and that the hysteresis loop of the control core 18 is selected from the condition

822

where H is the coercive s.

outer core 18; Hj. - coercive force of the core 17.

The mass and dimensions of the flat control core 18 are insignificant compared with the masses and dimensions of the core 17.

The windings 4, 5 and 19 are wound on the cores 17 and 18 (Fig. 2), and the windings 1 3 and 1 4 on the core 18 only.

The flat control core 18 is placed on the working core 17 so that their average lengths coincide, i.e.

where I, .- is the average circumference

 , ". УЛ yi 1Х1.Л iL

  core 17;

1., - average circumference

 core 18.

. The device works as follows.

When U is supplied from the input voltage source 1 (Fig. 2), an initial excitation circuit on elements 5 and 16 opens the thyristor 6, in which the current begins to flow in the anode circuit. For the purpose of stable operation of the inverter in a given frequency range, as well as eliminating input current ripples, a smoothing choke 2 is provided. The anodic current of the thyristor 6 is determined by the charging current of the switching capacitor and the current of the primary half winding 4 of the output transformer 3.

Due to the occurrence of mutual induction with the passage of current in the semi-winding 4 of the transformer 3 in the other semi-winding 5 occurs equal to the value of the EMF. The switching capacitor 8 is charged to double the power source 1.

When o, the same length of the cores 17 and 18 (Fig. 2), the magnetic field strengths of the latter will always be equal to each other, since their primary winding is common. When remaking the main core, the drain 20-2-1 in FIG. 4) the strength of its magnetic field remains almost unchanged, therefore, the control core 18 does not overmultiply and the emf in windings 13 and 14 is close to zero.

In this way, the back electromotive force in windings 13 and 14 is formed only due to the remagnetization of the main heart 17 and, respectively, at 3

The applied voltage is transformed only into windings wound on the main core 17.

After saturation of the main core 17 (points 21-23 in Fig. 4), the magnetic field strength increases dramatically due to a sharply increasing current, magnetization and reaches point 22 (Fig. 4) of the control core 18, which begins to demagnetise, and the working winding is now formed due to the reversal of the control core 18, and, accordingly, the applied voltage U is transformed only in the windings wound on the control core 18. In section 22-23 (Fig. 4) the control voltage of the control winding 14 is equal to

1 .Wl 3 Wp.

where 1y - EMF control winding 14; W is the number of turns of the control winding 14;

W is the total number of turns of the primary winding.

After the emf opens, closed thyristor 7 is opened and the whole process repeats.

The switching capacitor 8 through the thyristor 7 turns out to be connected to the power source 1 with reverse polarity and begins to recharge through the primary half windings 4 and 5 of transformer 3, acquiring the opposite polarity (shown in brackets in Fig. 1). As a result, a variable EMF is induced in the secondary winding 19. ,

The time of magnetization reversal of the control core 1-8 is determined by the switching time of the thyristors 6 or 7, and therefore its cross section should be sufficient for this condition.

Silicon diodes 9 and 10 close a small control voltage, which appears during magnetic reshaping.

41382

the working core 17 in the windings 13 or 14, and the resistors 11 and 12 orparize the current value of the opening pulse.

five

Claims (2)

Invention Formula I. Self-excited inverter, containing two power switches, connected together by one power terminals with the first input by conclusion five 0 five other power outputs with extreme outgrowths of the primary winding of a transformer having a main and 5 control cores and an output winding that controls the output of each power cell (through the limiting resistor and the diode is connected to the output of the control winding located 0 on the control core, switching and triggering capacitors, and a resistor, characterized in that, in order to improve the mass parameters by providing deep saturation of the main magnetic core, a choke is inserted between the second input terminal and. the middle terminal of the primary winding, to the extreme terminals of which under (the keys the switching capacitor, and the driving capacitor and resistor are connected in series and connected between the second input terminal and the control output of one of the keys, and the free inputs of the control windings are connected to the first input terminal EXECUTIVE. 2. The inverter according to claim 1, characterized in that, in order to increase reliability by reducing key current surge during switching, the main and control cores are made of a material having a rectangular hysteresis loop, have the same average length of the power line, the coercive control force core; not less than twice the core, and the saturation time. control core is not less than key switching time. / 3 / " i4-jj, pa F. J Hep Hey 20 (fJui.ff Compiled by V. Avdeev: Editor E. Kopcha Tekhred L. Oleinik Proofreader m. Demchik Order 3608/51 Circulation 631 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4