SU966833A1 - Static dc voltage to ac voltage converter - Google Patents

Description

(5 |) STATIC CONVERTER OF CONSTANT VOLTAGE TO AC VARIABLE

The invention relates to a converter technique and may be applied in static constant-voltage converters.

In investor transistors there are significant dynamic losses, which are accumulated from two components: losses from through currents and losses at the time the working point of the transistor passes through the linear region. The axial part of the dynamic losses is determined by the through currents, therefore the overwhelming part of the circuit solutions is directed towards their elimination. .

A device made according to the scheme of a bridge power amplifier is known in which the problem of eliminating through currents is solved.

The drawbacks of the device are the presence of additional transformers, the need to solve the problem of self-excitation, in addition, the total losses of the device are not reduced (the losses in the power transistors from through currents are eliminated, but the same appear in the additional elements).

A device is known in which through currents are eliminated.

Disadvantages of the device - the inclusion of additional devices in high-voltage circuits, which contributes to the dispersion of considerable power in them,

10 a large number of additional circuits, in high-power inverters with several parallel transistors, the circuit is much more complicated, the total losses are not reduced.

15

The closest in technical essence to the invention is a static DC / AC converter that contains an inverter, the output of which is connected to the output terminals, and the control input - to the output of a two-phase transistor preamplifier with a power choke. In this device, the removal of through currents is carried out by introducing an inverter between the base and the emitter of the transistors, a chain of a series-connected diode and one of the halves of the additional winding of the output transformer.

The disadvantage of this scheme is the inclusion of additional devices in the basic circuits of power transistors, which entails significant losses and, ultimately, the total power losses in the device are not reduced, and when used. When using a bridge converter with transformerless output, an additional transformer is required.

The purpose of the invention is to reduce the power loss of the device.

This goal is achieved by introducing two additional transistors into the static DC / AC converter, each of which has a parallel collector-emitter junction connected to one of the main transistors of the power preamplifier and connected to the bases of the main transistors of the opposite arms and through the input resistor with a common power bus.

The drawing shows a static converter circuit.

The device contains an inverter 1 (two-stroke circuit with a midpoint or a bridge circuit) and a pre-power amplifier containing a transformer 2, d; va of the main transistor 3 and connected by collectors to the transformer 2, the emitters to the common bus through the resistance of the h 5 power supply choke 6 with a discharge diode 7, two additional transistors 8 and 9 connected in parallel to the main transistors, and their bases through capacitors 10 and 11 are connected to the bases of the main transistors l and 3 through resistors 12 and 13 to the common wire.

The device works as follows.

At the base of the transistors 3 and control signals come. And simultaneously

but these signals arrive at the bases of transistors 8 and e through differential, dividing chains 10,11,12,13. Flyctb to the base of the transistor CS) came a sending signal, the same signal, differentiated 11 and 13 (10 and 12), goes to the base of transistor 9 (8) and for the time of the effect of the differentiated signal the transistors 3 are open

(k) and 11 (10). Simultaneous current flow through the primary windings of the transformer 2 causes it to saturate. i.e. its resistance tends to zero, and the entire voltage is applied to the choke 6, and in the output voltage of the preliminary stage there is a 1 pause (zero step), the duration of which is determined by the parameters of differentiating

circuits 10,12 (11,13). At the time of the pause in the open transistors of the inverter, minor carriers, i.e. closed transistors open when fully closed

open transistors, and therefore there will be no through currents through the transistors of the inverter.

In the proposed device, the number of high-current devices is reduced.

losses and, consequently, reduced losses, which distinguishes it from the prototype.

Claims (1)

Invention Formula A static voltage converter V-AC converter containing an inverter, the output of which is connected to the output terminals, and the control input to the output of a push-pull transistor preamplifier of power with a choke in the power supply circuit, characterized in power amplifier introduced two additional) (. transistors, each of which is connected by a collector-emitter junction connected in parallel to one of the main transistors of the preamplifier power, and through input capacitors connected to the bases of the main transistors of opposite shoulders and through input resistors - with common power bus.