DE2046462C - Regulated DC voltage converter - Google Patents

Description

The invention relates to a line converter for the delivery of a regulated connection with a power oscillator, the : r a transformer is magnetically coupled with a cm "resonance tension consiant holder, J with one depending on the output voltage Automatically controlled device adjustment of the frequency of the Lcistungsos / Illator. Such a converter is known (USA.-Patentrift 3 KW 133). Such DC voltage converters hold as an essential component as is well known: 1 self-excited inverter. Self-excited As is known, tables contain inverters Power oscillators for converting a DC voltage into a sinusoidal or square wave AC voltage. These inverters can also contain a power regulator and for conversion a DC voltage from one voltage value to another voltage value with a be connected downstream rectifier circuit. Such static inverters are used for Frequent applications in the low power range

ίο in push-pull circuit / used, two alternating Actuated electronic switches for periodic opening of opposing current paths are provided. The current paths allow current to flow through the primary winding of a Output transformer in opposite directions, whereby a voltage alternating on the secondary winding of the output transformer Polarity is induced. The electrical switches are switched over by a feedback device.

The self-excited push-pull inverter can be operated in two operating modes. In the first Operating mode, the transformer is magnetized within its linear range, while in the second and preferred mode of operation of the transformer is magnetized in such a way that saturation occurs in opposite directions during successive periods. The switching frequency of an inverter operated in the second operating mode is determined by the voltage value of the The supply voltage source and the characteristic values of the saturable transformer are determined. In the first Operating mode cause unwanted fluctuations in the input voltage as well as load fluctuations Changes in the switching frequency of the inverter or the power oscillator.

It is also generally known to use iron resonance voltage stabilizers in regulating devices for alternating voltages to use, which is mainly due to its simple structure with a minimal Number of components and a good one if the input voltage changes Enable regulation of the output voltage. The regulation is, however, when the frequency changes Insufficient input voltage or load changes. Because of these disadvantages, the use of resonance voltage stabilizers in converters of unregulated direct current in a direct current with a selectable constant amplitude is not very common. As above already mentioned, the frequency of a self-excited inverter changes with a Power oscillator as a function of the input DC voltage and, if applicable, the load.

Therefore, if the output voltage of such an inverter is applied to the input of an iron resonance voltage stabilizer is coupled, the output voltage of the iron resonance tensioning stabilizer would increase change depending on the frequency changes of the power oscillator.

In order to avoid this disadvantage, the known DC voltage converter (USA.-Patent 3 109 133) with a self-controlled power oscillator, an EisenrescMianz voltage stabilizer and a rectifier an adjustment dci Oscillator frequency for regulating the output DC voltage depending on the output

Guying provided. The adjustment takes place as a continuous control direct current through the development of a choke coil with non-linear niilinie, whereby by changing the amplitude - control direct current the inductance of the choke adjusted in series with an .informator winding of the power oscillator : old is.

In addition, the poor electrical efficiency is twofold, since the control current of the choke coil consumes an eighth control power. Another economic factor is that the -rn of the iron resonance voltage stabilizer is operated in a completely saturated range.
The object of the invention is to create a voltage converter of the type mentioned at the beginning with a selectable constant amplitude, rather with a lower economic increase and with lower losses, having good constant voltage output.
This object is achieved in such a GleichannungswandlT accordance with the invention.,: Ü the device for adjusting the frequency ^ of a parallel to the output of the Leisiungs- / illators lying series circuit of a low npedanz and a controllable switch and from IIER a time delay element having Steuerirrichtung for Jen switch of The type consists in that .uiP> the switch receives a switch-on signal with a delay after the beginning of each half-wave of the power oscillator, and that the delay of the time delay period is adjustable depending on the output voltage.

In one embodiment of the invention, the impedance is a choke and the switch is a triac provided and the series connection of these two elements in parallel to a separate secondary winding connected to the transformer.

Another embodiment of the invention is that the delay element from the separate Secondary winding of the transformer is also connected in series in parallel variable ohmic resistance and a capacitor and the connection between the Resistor and the capacitor are connected to the control electrode of the triac via a threshold value element is.

In a further embodiment of the invention it is proposed that the variable resistor consists of a fixed resistor and the za this resistor connected in parallel via a rectifier bridge circuit The emitter-collector path of a transistor and the emitter-base path consists of this Transistor acted upon by part of the output DC voltage of the DC voltage converter is.

The invention is described below with reference to an embodiment shown in the drawings explained in more detail; it shows

Fig. 1 shows an embodiment of a contained in the DC voltage converter according to the invention Inverter;

F i g. 2 A, 2 B show voltage timing diagrams of the alternating output voltage of a conventional saturation core working inverter and an inverter according to FIG. 1;

F i g. 3 shows a DC voltage converter according to the invention.

The in F i g. 1 shown inverter with a power oscillator is controlled by an unregulated DC voltage source 1, for example a battery, fed, which on the one hand with the emitter electrodes two switching transistors 10 and 20 and on the other hand with a central tap 34 of the Primary winding 33/35 of a saturable output transformer 5 is connected. The terminals 33 and 35 of the primary winding each lead to a collector electrode of the two switching transistors 10. 20, which by alternately switching to the conductive state a changing Magnetization of the transformer core in opposite directions and thus a rectangular shape Generate AC voltage at the output terminals 51, 52 of the inverter. So long the core of the transformer 5 works within the linear magnetization range, it will by a frequency adjustment device arranged parallel to connections 38 and 39 of the secondary winding 15 influenced in such a way that the transformer 5 works like a saturation transformer, without getting into the saturation area. The switching of the shark waves is thereby achieved by the frequency adjustment device. The mode of operation of the circuit arrangement according to FIG. 1 will be explained below with a description of a typical operating cycle.

It is assumed that the inverter is already in operation. First of all, the Switching transistor 10 in its conductive state and the switching transistor 20 in its blocking state or non-conductive state. Depending on the DC voltage at the

Voltage source, 1, a current flows through the collector-emitter path of the switching transistor 10 and the primary transformer sub-winding 33/34 back to source 1. This current rises for so long until it is limited by the impedance of the secondary winding 38/39 according to the transformation ratio will. During the current rise, a voltage is generated in the transformer winding 31/32 induced by the magnetic coupling with the primary transformer winding 33/34. The one at the

Voltage present in winding 31/32 is fed to base electrode 11 of switching transistor 10 and drives it even further towards its state of saturation.

The at the terminals 38 and 39 of the secondary Transformar.orwick 38/39 by the current in the Partial winding 33/34 induced secondary voltage affects the frequency adjustment device 15 in the Way that at a certain value of the secondary voltage the secondary transformer winding

38/39 is short-circuited, reducing the inverter output voltage drops sharply to zero.

The frequency adjustment device 15 contains an RC target element with a delay element as the delay element

variable resistor 41 and a capacitor 42 in parallel with the secondary winding 38/39 is arranged. The capacitor 42 is charged from the secondary winding 38/39, with the charging speed of the set resistance value

of the resistor 41 is dependent. The frequency adjustment device 15 also contains a series connection of an impedance in the form of a choke 43 and a switch in the form of a triac 46,

5 6

which also blocks switching transistor 20 in parallel with tier secondary winding. The at the same time de> -

38 / 3'y is arranged. The control electrode 64 of the winding 31/32 switches the induced counter voltage

Triacs 46 is through a Schwcllwertgiicd in the form of the transistor OK, so that the described

two reverse gcpoltcn and opposite gcpoltcn cycle starts again. For further understanding

Zener diodes 44. 45 with the capacitor 42 ver 5 of the invention is in Fi g. 2 B the output voltage

bound. The mode of operation of the triac 46 corresponds to that of the inverter described above.

the mode of operation of two anti-parallel connections, which in FIG

Thyristors that work via a common control known, with saturation transformer

electrode can be ignited. Inverter is compared for comparison.

The voltage curves I, II, III according to FIG. 2A capacitor 42 exceeds the capacitor voltage, giving the frequency response of an inverter the threshold value of the Zener voltage in the opposite direction to the voltage curve with a saturable transformer when the capacitor voltage changes. the supply voltage again. With a diode 44, 45, whereby in the present case the steady reduction of the DC supply voltage Zcncrdiode 44 becomes conductive and the capacitor 15 increases the switching period T _x , T ₂ or T ₃ , the voltage of the control electrode 64 of the triac 46 increases by a Frequency reduction of the frequency of the leads. The triac 46 ignites and closes the throttle due to voltage curves. However, since the saturation 43 is parallel to the secondary winding 38/39. The supply characteristics of the transformer core are fixed, throttle 43 has a low impedance, the voltage-time areas A _x, A _{2, Α} Λ III so are that the secondary winding 38/39 practically short ao curves I, II, equal. In Fig. 2B 'the is closed and the voltage on the secondary curves I, II, III the adjustable frequency response winding 38/39 very quickly on a negligible inverter, as it decreases with the inventively small value. is used in accordance with the DC / DC converter

Since the choke 43, despite the terminal voltage, reduces the DC supply voltage zero across the secondary winding 38/39 its current 45 again in the same way as above. The switching initially continues, a counter voltage is induced in the secondary winding periods T _x , T ₂ , T _{3 of} the curves I, II, III are equal to 38/39, which is over large, while the voltage-time areas of the transformer winding 3i / 32 the base output voltage cn reaches the decreasing value of the electrode 11 of the switching transistor 10 and reduce the supply voltage. The voltage changes quickly to its blocking state or non-time areas of the output voltages are switched over to the conductive state. At the same time it is also changed by the fact that when the voltage in the transformer winding 36/37 is reduced, a voltage DC supply voltage induces the time constant of the transistor 20, which reaches the base electrode 21 of the switching delay element of the frequency converter 15 and turns it into the conductive depending on the output DC voltage State switches. If the throttle current is automatically reduced to 35 as well. The switching has reduced the value zero. the triac 46 goes out frequency of the inverter described and is thus again in the blocking state. thus adjusted by the fact that the loading speed

By switching the switching transistor 20 of the capacitor 42 is changed. By

In the conductive state, a current flows from the position of the switching frequency of the inverter

positive terminal of the voltage source c 1 via the ₄₀ dependence on changes in the output

Kollcktor-Emittcr-Streckc of the switching transistor 20 voltage can the output DC voltage untci

and the primary transformer winding 34/35 using an iron described below

the negative terminal of the voltage source resonance controller to a selectable constant value

Be regulated during the current rise of the primary trans-

Formatorstroms is in the transformer winding 45. The DC voltage converter according to the invention

36/37 induces a voltage, which in turn contains a voltage shown in FIG. 3 that shown in FIG

increases the current. This current in inverter, being used to adjust the time

the transformer winding 36/37 reaches the constant of the delay element of the frequency

Base electrode 21 of the switching transistor 20 and drives adjusting device 15 a feedback of the dei

this by increasing the voltage in the forward 50 output DC voltage of the converter to di <

direction towards its state of saturation. Frequency adjustment device 15 is provided. Dci

During the current rise through the transistor, the power oscillator is denoted by 50.

20 is a voltage on the secondary trans- To generate the output DC voltage between

Formator winding 38/39 induces, which see the connections 81 and 82 of the converter

opposite direction to the previously induced 55 is used by an additional transformer

Having tension. Depending on this winding 61/63 fed rectifier bridge 66. Di <

Due to the reduced voltage, a current flows through the time feedback by means of a device K

circuit, which the capacitor 42 in opposite between the output terminals 81, 82 and de

set direction to the previous up frequency adjustment device 15.

direction of charge is charging. When the threshold is reached, the device 16 contains a switching transistor

value of the oppositely polarized zener diodes 44 70, which opposite terminals a, c a

The control bridge rectifier 65 is connected by the capacitor voltage. The two i

Electrode 64 of the triac 46 is supplied with an ignition current. other connections b, d of the bridge rectifier

so that it is switched to its conducting state. 65 are connected to the terminals of a fixed resistor 4 '

By the ignition of the triac 46, the throttle 65 is ver in the charging current path of the capacitor 42

43 connected and tied in parallel with the winding 38/39. The base electrode 71 of the acoustic transistor

induced in the manner described above, a 70 is fed in front of a potentiometer 75

Counter voltage on winding 36/37, which is the one between the output terminals 81.82 gc

schallet isi, Dk- I inilKiclcklroilf 72 of the switching termination, which is therefore independent of

transistor 70 isl on the one hand via a /.cncidiode 67 the core of the winding 38/3 ·) can form. the

with the Aiisgangsaiischluß 81 and on the other hand with the connections 61 and 62 of the winding 61 63

ei ca ti VVideisiand 74 connected to the output terminal 82 üeidiricl.terbrücke 66 delivers one

connected, whereby a further side channel dei 5 (ilcichspaimiing, whose waviness part is through the

Starting answer 81, 82 is present. The Glältungskoiulensalor 73 reduces win '. This

Zenerdiodc 67 Ικμΐ; m del Kiiiillerdcktmde 72 cmc smoothed DC voltage is the output

Voltage on. which are supplied to the Schwellspanniing of the connections 81, HZ, which to a not

Zener diode smaller than the consumption circuit shown at the output level must be connected

is. tine change in the DC input voltage.

This also changes the KmUtCr-ZBaSiS preload The mode of operation of the feedback device

of the transistor 70 and thus in turn the total 16 for regulating the DC output voltage to the

The resistance of the charging current path for the condensate connections 81, 82 is described below using the

sator42. Behavior of the inverter in response to a change

As already mentioned, the sound frequency 15 of its supply DC voltage must be explained.

of the inverter 50 from the voltage of the If, for example, the Vcrsorgungsspannimg des

DC voltage source 1 and the charging speed inverter SO increases, it increases

speed of the capacitor 42 is determined. Through the switching frequency. This increase in switching frequency

periodic switching of the inverter SO is based on the fact that increased voltage causes the condensate

a 20 sator 42 loads faster to the voltage value at the transformer winding 38/39

Rectangular alternating voltage is generated in which the simulated saturation of the winding 38/3)

similar form also occurs on the transformer winding. As the frequency increases at which

61/63 is present, since the voltage transition area and saturation occur, the equilibrium increases.

Rectangular output voltage of the winding average voltage value of the transformer

38/39 magnetically coupled with winding 61/63 »5 winding applied AC voltage 61/62 Da

i. ',. The winding 61/63 has a center tap that maintains the constant tension surfaces of the peri-

62, which together with the winding connection odical rectangular output voltage at the

61 connected to the Gieidificmürbruckc 66, winding 61/62 is now at a higher frequency

Parallcl to the winding connections 61 and 63 is generated, the size of the output increases accordingly

a capacitor 68 is provided. Together, 30 form the same input voltage at the connections 81, 82.

these components a Kiscnrcsonan /.- Voltage- This increase the output DC voltage

constant holder 69. The magnetic shunts cause a change via the device 16

60 of the winding 61/63 result in a sufficient charging speed of the capacitor 42 and

Isolation from the windings of the inverter - so that the voltage-time area of the inverter-

transformalors to saturation in the range of the 35 output voltage.

Allow winding 61/63. The magnetic core The Zener diode 67 of the device 16! Iah that of the winding 61/63 of the iron resonance voltage emitter electrode 72 is kept constant at a fixed reference voltage, 69 is in opposite direction because the output DC voltage is at the terminals during two successive circuits 81, 82 In the above example, increased voltage half-waves of the inverter output 40, the potentiometer 75 delivers a higher voltage, voltage saturated. This saturation has the effect that at the same time the resulting voltage reaching the base magnetic coupling of the secondary winding 38/39 of the transistor 70 would increase with the winding 61/63 during each ^{half-wool the impedance of the Kollcklor- / L:} miUer-Streckc is constant. The only parameter that causes transistor 70 to Vcr-. This also causes the change in the output voltage, the resistance in the charging circuit of the capacitor 42 is increased by the inverter switching frequency, so that the charging time of the capacitor 42 is the frequency at which saturation occurs. The increases and thus the switching frequency of the alternating capacitor 68 is selected so that it is reduced in relation to Richters50. This reduction be together with the leakage inductance of the magnetic acts a reduction in the transformer shunt 60 forms a resonance circuit, the so winding 61/62 AC voltage, sn resonance frequency close to the switching frequency that the output DC voltage of the converter is aul of the inverter 50. The capacitor 68 is lowered to the desired regulated value causes a voltage increase in the winding. The aforementioned feedback circuit 61/63, which drives the core of the winding 61/63 into the thus causes a constant regulation of the output saturation, while the core of the winding 55 drives DC voltage at the connections 81, 82, wöbe 38/39 remains unsaturated. The magnetic secondary the switching frequency of the power oscillator 50 al conclusions 60 close the magnetic path for the manipulated variable.

1 sheet of drawings

Claims (4)

Patent claims: 1. DC voltage converter for supplying a regulated DC voltage with a power oscillator. the magnetically via a transformer with an iron resonance voltage consiant holder is coupled, and with a device for adjustment that is automatically controlled as a function of the DC output voltage the frequency of the power oscillator. characterized in that the device for adjusting the frequency from a nar i! lel to the output of the power oscillator (501 series connection of a low impedance (43 and a controllable switch (46) and from a control device having a time delay element for the switch (46) consists of the type that the switch (46) delay after the beginning of each half-wave of the Power oscillator (50) receives a switch-on signal, and that the delay of the time delay element is automatically adjustable as a function of the output voltage. 2. DC voltage converter according to claim 1, characterized in that the impedance (43) a choke and a triac as a switch (46) and the Reiher.schalt ng these two Elements (43.46) parallel to a separate secondary winding (38/39) of the transformer (5) connected. 3. DC voltage converter according to claim 2, characterized in that the delay element from that of the separate secondary winding (38'39) of the transformer (5) if parallel-connected series connection of a variable ohmic resistor and one Capacitor (42) and the connection between the resistor and the capacitor is connected to the control electrode of the triac (46) via a threshold value element (44, 45). 4. DC voltage converter according to claim 1, characterized in that the variable resistor from a fixed resistor (47) and that to this resistor (47) via a rectifier bridge circuit (65) parallel-connected emitter-collector path of a transistor (70) and the emitter-base corner of this transistor (70) from part of the output DC voltage of the DC voltage converter is applied.