SU1343528A1 - Self-excited oscillator - Google Patents

Abstract

The invention relates to the field of converter technology and can be used to convert a constant voltage to an alternating voltage and to control the actual value of the voltage on the load. The auto-oscillator allows you to expand the range of regulation of the voltage ratio while maintaining the invariance to voltage and frequency constancy. The auto-generator includes a power transistor 1 and a switching transformer 2 with a power and control windings. The windings are connected in series and according to. The load resistor 3 is connected to the collector circuit of the power transistor 1. An adjustable resistor 4 is installed in the base circuit. The driver circuit 5 is connected to the common connection point of the adjustable resistor 4 and the control winding of the transformer 2. 2 sludge. i SL -o S1.

Description

From (5bt, relative to transducer technology, and can be used to convert the DC voltage to AC and control the actual value of the voltage across the load.

The purpose of the invention is to expand the range of voltage ratio adjustment while maintaining voltage invariance and frequency constant.

FIG. 1 shows the electrical circuit diagram of the auto generator; in fig. 2a, b are time diagrams of currents and voltages.

The auto-generator contains a power transistor 1 and a switching transformer 2 with power and control windings connected in series and according to, the midpoint of which is connected to the emitter of the power transistor 1, and the free input of the power winding is connected to the negative terminal of the power supply, the positive terminal of which is connected through a resistor

3 loads with collector of power transistor 1, adjustable resistor

4 and the timing circuit 5, one of the output terminals of which is connected to the emitter of the power transistor 1, and the other to the free output of the control winding and to one of the terminals of the adjustable resistor 4, the other terminal of which is connected to the base of the power transistor 1. The timing circuit

5can be made in the form of series-connected resistor and a diode, the base of which is connected to the emitter of the power transistor 1.

In another embodiment, the timing driver circuit may be implemented as a series-connected resistor and capacitor.

The operation of the device is as follows.

After switching on the power transistor 1, switching the transformer 2 begins to saturate, the voltage on the power and control windings drops (Fig. 26, curve A). When the load current flowing through the power winding is constant, the current ig in the control winding begins to decrease (Fig. 2a), since the coupling of the windings through the magnetic flux weakens due to the saturation of the switching transformer 2. At time t, the base current reaches zero and the power transistor 1 is turned off (for simplicity, the transistor – dongle switch does not delay). On t, -t of the off state of the power transistor 1, the switching transformer 2 consumes the energy stored in the 0-t interval of the on state in the circuit consisting of the control winding of the switching transformer 2 and the driving circuit time 5.

The amplitude of the voltage arises on the control winding of the switching transformer (curves B and A, Fig.26), and consequently, the duration of the interval t, t. the type of timing of the driver circuit 5 and the value of its resistor are determined. An increase in the value of the resistor leads to an increase in the amplitude and a reduction in the duration of the interval t – t with a constant interval of 0– t, which ensures the equality of the volt – second areas under the curve

and

TR

(Fig. 26) on these trails.

5 Thus, the resistor of the master circuit time 5 is used as the y rate of the closed state. If it is adjustable, then it can be used with the controllability of the interval t ,.

0

five

0

only

However, the effectiveness of voltage regulation on the load resistor 3 due to a change in the value of the resistor is low, since the duration of the interval t is relative. The -t is significantly shorter than the open state interval 0-t of the power transistor 1. For basic voltage control. a load resistor 3 uses an adjustable resistor 4, the value of which determines the duration of the interval 0-t. An increase in the adjustable resistor 4 leads to an increase in the voltage amplitude on the windings of the switching transformer 2 during the on state of transistor 1 (curve C, Fig. 26) and to a decrease in the interval duration 0-t with an almost constant interval duration, j. The invariance of the interval duration to the value of the adjustable resistor 4 when using the time of the master circuit 5 can be provided by a diode which disconnects the time of the master circuit 5 from the control winding at the interval 0-t, and at the interval t, the diode conducts a constant TO. only the magnitude of the resistor 3 load. When used

0

By setting the time of the master circuit 5 made of a series-connected resistor and capacitor, an increase in the value of the adjustable resistor 4, along with a decrease in the interval 0-t, leads to a certain increase in the interval t -t, j, since in this case the interval driver circuit 5 is charged by the current of the control winding of the switching transformer 2. Here, the voltage is controlled within wider limits and with a more stable frequency of the oscillator.

Claims (1)

Invention Formula An oscillator containing a power transistor and a switching transformer with power and control windings connected in series and according to, the common connection point of which is connected to the emitter of the power transistor, and the free output of the power winding is connected to the minus terminal of the power supply, the plus terminal of which is connected via a load resistor to the collector of the power transistor, the base of which is connected to the free output of the control winding through an adjustable resistor different the fact that, in order to expand the range of regulation of the duty ratio of the voltage while maintaining the voltage invariance and frequency constant, it is provided with A chain of series-connected resistors and a capacitor, one of the output terminals of which is connected to the emitter of the power transistor, and the other to the free output of the control winding. FIG. 2 Compiled by V.ZhUravlev Editor N.Gunko Tekhred L.Serdyukova Proofreader M.Sharoshi Order 4835/55 Circulation 659 Subscription. VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, Projecto st., 4