SU964613A1 - Parametric transistorized stabilizer - Google Patents

Description

(S) PARAMETRIC TRANSISTOR STABILIZER The invention relates to electrical power engineering and can be used, for example, in secondary power sources. . The parametric transistor stabilizers are known, in which the power transistor is controlled from a transformer connected in an open-power-transistor tact to a power source via a specified power transistor (or control transistor) 1 and f 2). These transistors are locked when the core of the transformer is magnetized, and the parametric stabilization of the running voltage is provided by demagnetizing the core of this transformer in the closed state of the power transistor according to a definite, for various types of circuits — a series stabilizer, a stabilizer with an output galvanically discharged . d., a different law. The closest technical solution to the invention is a parametric transistor stabilizer, which contains an amplifier on a controlled multivibrator with a transistor and a magnetizing transformer, the primary circuit of which is connected in parallel to the power supply circuit, the reference voltage source and the output filter C3. In the known stabilizers, parametric stabilization of the output voltage is achieved when the supply voltage varies and the load is within wide limits, but the power element of the transistor is not protected during start-up and overloads and short-circuits in the load. The introduction of separate current protection devices to the stabilizer complicates the stabilizer by directly introducing the protection device and the interface of the protection device to the stabilizer circuit.

3 96 The aim of the invention is to enhance the functionality of the stabilizer by providing operation in case of overload and short circuit in the load.

The goal is achieved by introducing a decoupling diode, a ballast resistor, a negative feedback winding, and a tap from the primary winding of the magnetizing transformer into the parametric transistor stabilizer, the indicated unlocking diode, the polarity of which is opposite to the polarity of the source stabilizer connected to the input terminals. power, connected in series to the primary circuit of the transformer, the free output of the decoupling diode is connected to the input terminal directly or through a specified transistor, the ballast resistor shunts a series circuit consisting of a part of the primary winding with a tap and an isolating diode, as well. The negative feedback winding of the transformer is connected to the power supply circuit.

FIG. 1 and 2 shows variants of the stabilizer functional diagram.

The stabilizer contains (Fig. O power (control) transistor 1, parallel magnetizing transformer, mat 2, primary winding 3, tap 4, control power winding 5, and simultaneously controlling transistor 1, winding 6 negative feedback, ballast resistor 7, base resistor 8, stabilizer starting unit 9, decoupling diode 10, reference voltage source 11 (Zener diode), capacitor 12, respectively, diode 13 choke 1 and LCD capacitor 15 of the output smoothing filter, power source 16, load 17 connecting diode 18.

It is also possible to perform when the capacitor 12 and the connecting diode 18 are not included in the circuit (Fig. 2) and the control winding 19 of the power trazistor 20, the base resistor 21 of the power trazistor, the zener diode 22, the diodes 23-25 and the resistor 2c included in the source 11 of the reference voltage, respectively, is the primary and secondary winding 27 and 28 of the power drossel 1+.

The stabilizer (Fig. 1) works as follows.

34

When the device is connected to the power supply voltage, the transistor 1 is transferred to the saturation region by the starting unit 9. The capacitor 12 is charged quickly up to a stabilization breakdown voltage, after which the stabilizer begins to operate.

. The forward direction of the transformer 2 is reversed by a voltage (in fdcTiif and in the opposite direction by a voltage UCT-H which is fixed by a capacitor 12.

The reverse magnetizing circuit is closed through the diode 13 displaced in the forward direction. Throttle 1 and capacitor 15 provide the necessary filtering of the output voltage -.

The switching of the power transistor 1 occurs when the transformer 2 is magnetized, and the output voltage is maintained by the parametric constant method

 w shg - the equation of equality in with on the winding 3

transformer 2 - (and cGist) j; / T

71 CT -p-jr-T, whence Un -frUcT-.

g, i is the time of the open sotoni transistor,

v T is the switching period of the transistor.

Thus, Ug, Uj. const. This mode of operation is maintained at the rated current of the power transistor 1, when the ampere-turns of the current through the ballast resistor 7 exceed the ampere-turns of the windings 5 and 6, and the difference between the indicated currents brought to the winding 3 provides the current through the isolating diode 10 , e. provides the voltage across the winding 3 with the open power transistor 1 equal to U ,,. UCT-H,

Claims (1)

When the transformer 2 core is demagnetized, the voltage on the winding 3 equal to UCTI-I is provided by creating a current in the connecting diode 18, i.e. from the capacitor 12 through the part of the winding 3 between, its output and the tap in the forward direction, and the diode 13 and the ballast resistor 7 generates a current slightly exceeding the sum of the no-load current of the indicated part of the winding 3 and the reduced reverse current U. of the power transistor 1. When overloaded and short-circuited in the load, the current of the sylh) of the transistor 1 increases and, accordingly, in the winding 6 negative feedback. Starting from the set value of the current of the power transistor 1, the current of the base resistor 8 begins to decrease due to the fact that most of the current through the ballast resistor 7 is compensated by the current of negative feedback. With a further increase in the current of the power transistor 1 and, accordingly, a decrease in the current of the base of the power transistor 1, this transistor switches to the linear limiting mode; its collector current and, consequently, the limitation of the load current. The maximum possible current through the power transistor 1 when its current gain equals pa to the current through the ballast resistor 7 reduced to negative winding 6. Practically (b is never equal to ω, therefore, the real maximum current of power transistor1 is less than theoretically possible.. When the power transistor goes into linear mode while operating in current limiting mode, relatively long operation of the power transistor 1 in linear ren (ime or switching off, i.e., transition to the demagnetization mode of the transformer core 2 o The connecting diode 18 is not of principle, because it is caused by the chosen specific circuit implementation of the demagnetization of the transformer core 2 (ph o 1) .Stand-through stabilizer with galvanic isolation and preamplifier is one of the possible device variants (Fig. 2). In the above diagrams it is possible to connect the isolating diode 10 to the power supply terminal directly or through a power transistor: and also it is possible to connect as the positive and negative terminals of the power source of the dissipating diode 10 and the ballast resistor 7. The property of the proposed stabilizer to limit the maximum possible current in the power transistor determines the expansion of the functional ozmozh NOSTA proposed stabilizer compared to known, ie. e. able to work during overload and short circuit in the load. Claims of the invention A parametric transistor stabilizer containing an amplifier on a controlled multivibrator with a transistor and a magnetizing transformer, the primary circuit of which is connected in parallel to the power supply circuit, a voltage source and an output filter, characterized in that in order to extend the functionality of the stabilizer by to provide work in case of overload and short circuit in the load, an isolating diode, a ballast resistor, and a winding are introduced into it Feedback and removal from the primary winding of the magnetizing transformer, let’s take the indicated decoupling diode, the polarity of which is opposite to the polarity of the power supply stabilizer connected to the input terminals, is connected in series to the primary winding of the transformer, the free output of the isolating diode is connected to the input terminal stabilizer directly or through a specified transistor, the ballast resistor shunts a series circuit consisting of a part of the primary winding with a tap m and decoupling diode, .a winding negative feedback transformer included in the power supply circuit. Sources of information taken into account in the examination 1. F. Alexander I. and Sivakov A.R. Pulsed semiconductor converters and voltage stabilizers. L., Energie, 1970, fig. 2-15 s, 71.2. Kiselev L.N. and Mashukov E.V. Pulse voltage regulator at transistors. Bulletin of the electrical industry, №8, 136g. 3. Kossov 0. A. Power amplifiers in transistors in the switching mode. Ed. 2nd (revised and enlarged), M., Energie, 1971, fig. 12-. 33, p. 352.