SU819903A1 - Voltage converter - Google Patents

Description

(54) CONVERTING-VOLTAGE

The invention relates to electrical engineering and relates to the conversion and regulation of electrical energy. A known voltage converter, in which two power transistors connected in parallel are alternately opened with a current, is proportional to the current of their collection ... from a common current transformer. L The known converter has a high gain factor, since it can be controlled by short starting and switching off signals. . Its disadvantage is an increase in losses in power transistors when they are switched, when the total current of the bases is zero. The closest to the invention is a voltage solution that consists of two power transistors, the collectors of which are connected to each other, to the collectors of the respective auxiliary transistors and to the input terminal, and the emitters are connected to each other through the primary windings of the transformer connected with a glasio-series, to the common point of which the output terminal is connected, with the secondary windings of the transformer connected in series between the auxiliary emitters and the bases In addition, the base of the auxiliary transistors is connected to one of the outputs of the control voltage source 2. When switching power composite transistors, there is no moment when the total base current is equal to and therefore the losses in the power transistors are lower than in the scheme | 1. A disadvantage of the known circuit 2 is the relatively low gain — the open-circuit voltage circuit requires a constant unlocking signal. The purpose of the invention is to increase the gain (to achieve the ability to control short unlocking and locking pulses) while maintaining a low value of losses in the power transistors. This goal is achieved by c. The voltage converter of the base of the power and auxiliary transistors is combined with each other, and the second high voltage & voltage of the control voltage source is connected to the junction point of the auxiliary mitters, tel transistors.

The drawing shows a schematic diagram of the converter.

The converter contains power transistors 1/2, auxiliary transistors 3, 4, transformer 5 with primary windings 6, 7 and secondary windings 8, 9. Load Yu through a converter connected to the power source 11 (Vntn-) control circuits of the auxiliary transistors 3, 4 through the ballast resistors 12, 13 are connected to the source 14 of the control voltage ()

The converter works in the following way.

The positive control signal opens up the transistors 3, 4. Due to the difference in the characteristics of the transistors, a slightly larger current will flow through the transistor 3 than through the transistor 4.

As a result, transistor 1 will also open slightly more; transistor 2. In this case, a voltage is applied to the windings of the transformer 5 with a plus on the beginnings of the windings, indicated by dots. The voltage on the clamp 8 provides a positive displacement of the transistor 1 and the unlocking of the transistor 3. The voltage on the winding 9 locks the transistor 4, the sum of the voltages of the windings 8 and 9 locks the transistor 2.

After magnetizing the core of the transformer S, the transistor 3 is closed. A self-induced emf is induced on the windings 8 and 9, which will open the transistors 4 and 2 and close the transistor 1..

Since the transition to the cut-off mode of the transistor 1. Due to resorption of minority carriers in its base occurs after the unlocking of the transistor 2, then when the transistors are switched in the converter, the voltage on the power terminals of the voltage converter does not increase, i.e. no dynamic loss.

Subsequently, the processes are repeated, after the initial unlocking of one pair of transistors (3.1 or 4, 2), the need for unplugging the signal from source 14 disappears, since the auxiliary transistors 3, 4 are opened from the windings 8, 9 of the transformer 5.

To turn on the voltage converter, it is sufficient from the source 14 of the control voltage to provide a signal that blocks the auxiliary transistors 3,4.

The duration of this onpei signal is made by the time of locking these transistors.

To eliminate the self-converter converter, it is sufficient to bridge the transitions of the power transistors 1, 2 with resistors, or to send a weak locking signal from source 14. In the voltage converter, shutdown and hold in closed

condition can be produced by NORMAL1 4

in a standard way, as in conventional transistor power amplifiers.

The drawing shows one of the variants of the scheme. In other embodiments of this voltage converter, the primary windings of the transformer can be included in any suitable places (for example, in the collectors of power transistors), can be used as power and auxiliary transistors of different types of conductivity, can be connected to the inputs of the auxiliary transistors instead of windings 8 and 9 windings or one common winding when shunting their base-emitter junction diodes, etc.

The voltage converter allows you to dramatically simplify the control circuit of the converter or a group of converters used, for example, in contactless circuit breakers of the network (BES).

Claims (2)

1. US patent 3671844, cl. H 02 M 3/22, 1972. 2. USSR author's certificate 470058 cl. H 03 F 3/00, 1975.