SU714588A1 - Adjustable converter - Google Patents

Description

I

The invention relates to electrical equipment and can be used in autonomous systems of power supply for the apparatus of communication and automation tours.

Lime voltage converters containing a master oscillator, a power amplifier, a rectifier with (} ml and an overload protection circuit, for example l.

The disadvantage of the known body transformation is low efficiency, since in it, the driver and the protection circuit are powered by a low voltage obtained from a high voltage by quenching most of the voltage on the ballast resistor.

The closest technical solution to the present invention is a single-cycle adjustable DC / DC converter containing power and auxiliary amplifying cascades included in the primary load of the output transformer, the secondary winding of which is loaded on a half-wave rectifier with LCD-phiptrom, as well as pulse width modulator that controls the switching of a power stage transistor and a control circuit

p. The disadvantages of this converter are low functional reliability, since it does not protect circuit elements during short circuits, and considerable power losses in the pulse width modulator and in the excitation circuit of the power transistor, especially when the input voltage is increased. life.

The purpose of this invention is to increase the functional reliability and efficiency of the converter.

The goal is achieved by the fact that the adjustable transistor envelope; containing power and auxiliary transistor amplifying cascades, included in the primary half windings of the output transducer, the secondary winding of which is loaded on a half-wave rectifier and L LED filter, and so vkoV o / 1ultor 111I1 are impulse and UGT circuit) RT, L.R.O. Stabilized by the first and second complementary transistors, the output TpaHC ({x3pN aTop is equipped with an additional clamping with a series-connected first diode, and the pulse iurine modulator is designed as an additional trans junction with primary, secondary control coil with a successively connected second diode, with the primary winding of an additional transformer through a chopper, which is connected to the control circuit, second to the winding of the first filter, connected to the control circuit, second to the winding of the first filter a parallel RC chain is connected to parallel inputs of the first and second additional transistors, the emitters of which are connected via a second parallel RC chain to the base of the power amplifier transistor the first additional transistor is connected to the emitter of the transistor of the power amplifier stage, the collector of the second additional transistor is connected to one end of the additional winding of the output transformer via the first diode, the other end of which is connected to the emitter of the power transistor about the cascade and between; The third secondary parallel circuit is connected to the collector of the second additional transistor and the midpoint of the primary half windings of the output voltage of the transformer. The drawing shows a schematic diagram of an adjustable converter. Converter 1 comprises a power amplifier and an auxiliary transistor 2 stages included in the primary poluobmotki 3 and 4 output Transfrm Matora 5. The secondary winding 6 of the output transformer 5 is loaded on the half-wave rectifier 7 and a throttle 9. tiCflfiltrov converter provided with a first and second 1D 11 dopolnitelnymi- transistors. The output transformer 5 is provided with an additional winding 12 with a series-connected first diode 13. The pulse width modulator 14 of the converter is designed as a double-pin transformer 15 with a primary 16, a secondary 17 winding, and a control winding 18 with a successively turn on the eHHbiN BTOp rM diode 19. additional transformer 15 through limiting switchgear 20 on the switch on parallel to parallel 9. Control wake 18 of additional transformer 15 with series wired switch 1M second digg 19 is connected to The control circuit 21, The secondary winding 17 of the additional transformer 15 is connected via the first parallel PC-chain 22 to the parallel-connected inputs of the first 10 and second 11 additional transistors. The emitters of these transistors are connected via the second 23 parallel RC-chain to the base of the transistor 1 of the power of the amplifying cascade Collector the first additional transistor 10 is connected to the emitter of the transistor 1 of the power amplifier stage. The collector of the second additional transistor 11 is connected via a diode 13 to one of the ends of the main winding 12 of a power transformer 5. The second end of the additional winding 12 is connected to the emitter of the power transistor 1. / Between the collector of the second additional transistor 11 and the midpoint of the primary half windings 3 and 4 of the output transformer 5, a third is connected parallel to the RC chain 24. A starting circuit 25 serves as a trigger for converting the actuators. The principle of the proposed converter is as follows. The power transistor 1 provides a working stroke, at which the power is transmitted through the half-winding 3 of the output transformer S, the single-field rectifier rectifier 7 and the choke 9 to the output of the converter. The switching transistor cascade 2 connects to the input voltage of the primary half-winding 4 of the output transformer 5 and provides reverse reversal of the transformers P locked with an external signal by the power transistor 1, and the reverse magnetization reversal time of the transformer 5 is less than the time of the locked state of the power transistor 1. pauses in each peri-. The operation of the output transformer 5. The converter is started by supplying the input voltage and using the starting circuit 25, for example, from a series-connected button and a resistor. At start-up, a blocking signal is applied to the first additional transistor 1O and from 57 a second signal to the second additional transistor 11, which sends a second 23 and third 24 parallel RC-switches and unlocking signal to the base of the power transistor 1 through the junction collector-emitter. transistors 1 and 11 in the open state, and transistor 10 in the closed state is provided by positive feedback through the output transfer device 5, rectifier 7, choke 9, additional transformer 15 and the first parallel A new RC chain 22. Moreover, the base current of the power transistor 1 comes from the auxiliary winding 12 of the output transformer 5 through the diode 13. The switching process of the power transistor 1 is as follows. The voltage from the droplets 9, having a rectangular shape, is fed through the limiting resistor 2O to the primary winding 16 of an additional transformer 15. An additional transformer 15 is reversible in the forward direction and sets the time intervals of the pulse width modulator 14. When the core is raised, of transformer 15 drops to zero voltage at its vtorichnoyobmotke 17 and a capacitor 22 parallel to the first T-chain C reverses the current to the parallel inputs of the additional transistors 10 and 11. wasp schestvl their active switching. At the same time, you cut off the second basic transistor 11 of the direct basic GOK of the power transistor 1 supplied by the additional winding 12 of the output transformer 5 through the diode 13. The power transistor 1 is turned off by the RIW transformer 5. When it is disconnected, the second parallel RC chain 23 promotes the dissipation of excess charge in the base of the power transistor 1, which provides an improvement in the force of the trip and the reduction of dynamic power losses. power transistor 1. When the power transistor 1 is disconnected, the polarity of the voltage on the choke 9 changes and the polarity of the voltage on the secondary winding 17 of the additional transformer 15 also changes. With this voltage the additional transistor 11 is kept in a closed state In this case, the additional transistor 10 is in the open state and therefore the power transistor 1 is closed, i.e. in his work

-. 8 now pause. The duration of the pause is determined by the time of reverse rewinding of the additional transformer 15 from the voltage coming from the droplets 9. With the beginning of the pause, the reverse reversal of the transformer 5 through the auxiliary transistor 2 and the primary half winding 4. The end of the pause occurs when the core of the additional transformer 15 is saturated, This drops to zero the voltage on its secondary winding 17 and the capacitor of the first 22 parallel RC chain provides the reverse of the additional currents for the base currents. Stores 10 and 11. At the same time, through the third 24 and second 23 parallel RC chains, an initial surge of the base current of the power transistor 1 from an external power source is given, and all transistors are held along the positive feedback circuit, as described above. Regulation is carried out by changing the time intervals of the pulse width modulator 14 (working stroke, pause), which depend on the bias current of the control winding 18 of the additional transformer 15 through the second diode 19 specified by the control circuit 21. The pulse width modulator time intervals 14 are selected that the output transformer 5 does not saturate in the interval of the working stroke, but operates in a linear segment. The working stroke corresponds to the reversal mode of the additional transformer 15 in the forward direction, and the pause corresponds to the reverse reversal of the additional transformer 15. In a short circuit, the oscillation in the converter breaks down automatically due to the fact that the additional transformer 15 is saturated in one direction, i.e. the amplitude of the half-wave voltage on the choke 9 increases and decreases the working time, the reverse half-wave voltage on the choke 9 disappears, and for this reason the capacitor of the first 22 parallel RC chain does not recharge, the additional transistor 11 does not: 1 is being dug, and power transistor 1 does not receive an initial base current surge. The effectiveness of the described device as compared with the prototype entails an increase in the functional reliability, ti by ensuring the protection of power

Claims (1)

Claim Regulated converter comprising input terminals connected to the transistor inverter stage with an output transformer whose secondary winding via a rectifier and is connected to the output LCflfilgr vyvbdam ₁ which through a pulse-impulsnyy'modu trimmer connected inverter with transistors _T cascade, characterized in that, in order increase functional reliability and increase efficiency, 5, the converter is equipped with additional transistors, the bases and emitters of which. are respectively interconnected and connected through the first RC circuit to the winding of an additional transformer, 10 the other winding of which is connected to a pulse-width modulator, the third winding through a resistor is connected to the choke of the LSD filter, and the emitters of additional transistors are connected via 15 to the second RC circuit to a transistor of the inverter stage, the collectors of these transistors are connected via a diode to the additional winding of the output transformer, and the collector of one of the 20 transistors is connected through a third RC circuit with an input terminal, which is connected through a resistor to the base of another additional transistor.