RU21488U1 - VOLTAGE TRANSFORMER - Google Patents

Description

The utility model relates to the field of electrical engineering and can be used in secondary power sources.

The converter is known, described in USSR author's certificate No. 1274087 according to MKI4NO2MZ / 335 for 1986, containing a chain of series-connected first and second capacitors connected in series with respect to two DC busbars and connected in series to a current-controlled circuit of the first and second transistors (in analog, an amplifier power), two transformers, the primary windings of which are connected in series between the point of connection of the first and second capacitors, on the one hand, and coupling the first and second transistors, on the other hand, with the secondary winding of a transformer via a rectifier diode and a smoothing filter connected to the load element.

A disadvantage of the known converter is a very complex control and protection scheme for trajistors, containing more than ten logic elements.

The closest in technical essence to the claimed technical solution is a half-bridge resonant oscillator, described in the collection edited by Yu.I. Koneva "Electronic Engineering in Automation, M.," Radio and Communications, 1986, issue. 17 (see Fig. 2 on page 138).

The known device contains parallel connected relative to two DC bus voltage, a chain of series-connected first and second capacitors and series-connected in a current controlled circuit of the first and second transistors, a current transformer, a first output transformer, first and second diodes, a smoothing filter and a load element, and the inputs the primary windings of the current transformer are the control inputs of the voltage converter, the end of the first and the beginning of the second secondary winding ok the current transformer is connected to each other and to the connection point of the emitter of the first and collector of the second transistor, the end of the second secondary winding of the current transformer is connected to the beginning of the primary winding of the first output transformer, the beginning of the secondary winding of which is connected through a directly connected first diode and a smoothing filter with the first input of the load element , the second input of which is connected via a common bus to the end of the secondary winding of the first output transformer, the beginning of the third secondary winding of the transformer is and is connected to the emitter of the second transistor and

negative bus DC input voltage, the positive bus which is connected to the collector of the first transistor.

The disadvantages of the known device, mainly, are its relatively low coefficient of performance (COP) and complexity. At the same time, low efficiency is due to significant energy losses in a complex output transformer, as well as in transistors due to the use of a relatively slow switching circuit. Significant losses in the output transformer are caused by the need to have a relatively large inductive dissipation power in its primary winding in order to provide a resonant circuit together with the corresponding capacitors. This reduces the coupling coefficient between the primary and secondary windings of the specified transformer, which allows you to transfer energy to the output with large losses.

The re-complication of the known device is associated with the use of a multi-winding output transformer in it, and with the provision of a certain inductive dissipation power for the formation, as already mentioned above, of a resonant circuit. This, of course, affects the manufacturability and maintainability of the device and, as a consequence, the cost of its manufacture and operation.

In addition, the known device in connection with the above energy losses is a source of electromagnetic interference.

The purpose of the claimed technical solution is to eliminate the above disadvantages, i.e. - higher than the SSC voltage converter relative to the known prototype, as well as the reduction of its electromagnetic interference.

This goal is achieved mainly by the fact that the complex multi-winding output transformer used in the prototype is replaced by two simple single-coil two-winding transformers, a third capacitor is introduced, connecting the connection point of the first and second capacitors to the connection point of the first and second transistor, the third and fourth diodes connecting reverse switching, respectively, the first and second transistors emitter with a collector.

In addition, anywhere in the resonant circuit, the primary winding of the second current transformer is turned on, the secondary winding of which is connected with an additional secondary winding of the first current transformer, and correction circuits consisting of dividing, directly connected, diodes passing only one are added to the base circuit of each transistor side the constant component of the current and the fourth (fifth for the second transistor) capacitor connected in parallel with them, to pass the alternating current component of the current I am transistors.

These distinctive features provide improved switching performance of transistors, reducing energy loss and reducing electromagnetic interference. In proportion to this, the efficiency of the device increases.

As shown by experimental studies conducted by the author, the efficiency at switching frequencies of more than 100 kHz can be increased by 7-10%.

This is the technical result of a utility model.

With the reduction of all the essential features, the goal stated above is achieved by the fact that in a voltage converter containing a chain of series-connected first and second capacitors connected in series to a controlled current circuit of the first and second transistors, the first current transformer, the first output a transformer, first and second diodes, a smoothing filter, and the conclusions of the primary winding of the first current transformer and used as the control input of the voltage converter, the end of the first and second second secondary windings of the first current transformer are connected to each other and to the connection point of the emitter of the first and second transistor collectors, the end of the second secondary winding of the first current transformer is connected to the beginning of the primary winding of the first output transformer, the beginning of the secondary the windings of which are connected through a direct-connected diode and a smoothing filter with the first output for connecting the load, and the end of the secondary winding of the output transformer is connected to the BTOpbJM output for connecting the load and to the common bus, the beginning of the third secondary winding of the first current transformer is connected to the emitter of the second transistor and to the negative DC bus, and the collector of the first transistor is connected to the positive pin of constant input voltage, the second transformer is introduced current, second output transformer, third and fourth transistors, three capacitors and ten diodes, with the end of the primary winding of the second output transformer pa is connected to the end of the primary winding of the first output transformer, the beginning of the primary winding of the second output transformer is connected to the connection point of the first and second capacitors and to the first terminal of the third capacitor, the second terminal of which is connected to the connection point of the emitter of the first and collector of the second transistor, the beginning and end of the secondary winding the second output transformer, respectively, connected to the first output for connecting the load through a direct-connected diode and a smoothing filter and with the second pin With the load connection, the anode and cathode of the third diode are connected respectively to the emitter and collector of the first transistor, the anode and cathode of the fourth diode are connected respectively to the emitter and collector of the second transistor, the beginning of the nerve secondary winding of the first current transformer is connected through parallel connected fourth capacitor and series-connected directly connected the fifth and sixth diodes with the base of the first transistor, the connection point of the fifth and sixth diodes through the seventh diode connected and the collector of the first transistor, the third end of the secondary winding of the first current transformer is coupled across parallel coupled fifth

0-. ,

a capacitor and series-connected direct-connected eighth and ninth diodes with the base of the second transistor, the connection point of the eighth and ninth diodes through the indirectly connected tenth diode is connected to the collector of the second transistor, the primary winding of the second current transformer is connected in series anywhere in the resonant circuit, consisting of the primary windings of the first and a second output transformer, a second secondary winding of the first current transformer and the third capacitor, wherein The primary winding of the second current transformer is turned on in turn with the windings included in the resonant circuit, the beginning of the secondary winding of the second current transformer is connected to the bases of the third and fourth transistors, and its end is connected to the emitters of these transistors and to the end of any of the secondary windings of the first current transformer, at the beginning of the used winding is connected through a direct-connected eleventh diode to the collector of the third transistor and through a reverse-connected twelfth diode to the collector of the fourth transistor and the end - with the connection point of the emitters of the third and fourth transistors, and the third and fourth transistors have conductivity of the pp-p and p-p-p type, respectively.

Without the use of a second current transformer, a dangerous situation arises of simultaneously opening the first and second transistors, through which in this case a short circuit current flows, leading to their failure.

This disadvantage can be eliminated by introducing a stronger inverse blocking connection into one of the already used (or additional) windings of the current transformer from the resonant circuit formed by the third capacitor together with the primary windings of the output transformers. For this, a current sensor can be connected in series at any point on the resonant circuit.

Moreover, as a current sensor with a varying degree of the obtained effect, elementary elements (such as a nonlinear element or a conventional resistor) can be used without additional galvanic feedback from this element to the current transformer windings.

The greatest effect is achieved by the current sensor, which is a unit that provides signal amplification and galvanic feedback from the resonant circuit to one of the current transformer windings or an additional winding. As such a current sensor, for example, a second current transformer can be used, the primary winding of which is sequentially connected at any point on the resonant circuit, and the secondary winding, which, through a transistor switch, can be directly connected to one of the windings of the first current transformer.

, -

In FIG. 1 is a circuit diagram of an example implementation of a voltage converter, and FIG. 2 is a diagram illustrating its operation.

The voltage converter contains the first and second capacitors 1 and 2, the first and second transistors 3 and 4, the first current transformer 5, the first output transformer 6, the first and second diodes 7 and 8, a smoothing filter 9, containing inductance 9.1 and capacitance 9.1 and element 9.2, element 10 load, the second output transformer 11, the third, fourth and fifth capacitors 12,13 and 14, the third ... tenth diodes 15, 16, 17, 18, 19, 20, 21 and 22, the control inputs 23 and 24 and the bus constant input voltage 25 and 26. In addition, the voltage Converter further comprises a current sensor 27 (W second current transformer) comprising, in turn, a primary winding 27.1 and a secondary winding 27.2, the third and fourth transistors 27.3 and 27.4 and the twelfth and thirteenth diodes 27.5 and 27.6 (see FIG. 1). Moreover, the beginning of the primary winding 27.1 of the second current transformer is connected to the beginning of the primary winding 6.1, and the end of the primary winding 27.1 is connected to the end of the second secondary winding 5.3 of the first current transformer 5. The beginning of the secondary winding 27.2 of the second current transformer is connected to the bases of the third and fourth transistors 27.3 and 27.4, and its end is connected to the emitters of these transistors and to the end of the fourth (additional) winding 5.5 of the first current transformer 5. The beginning of the additional winding 5.5 of the first current transformer 5 is connected through a direct-connected diode 27.5 with a collector of the third transistor 27.3 and through a reverse-connected diode 27.6 with a collector of the fourth transistor 27.4. The third and fourth transistors 27.3 and 27.4 have different conductivities, respectively, pp and pp.

The current transformer 5 contains a primary winding 5.1 and a first, second and third secondary windings, respectively 5.2, 5.3 and 5.4, as well as an additional winding 5.5.

The first and second output transformers 6 and 11 contain primary windings 6.1 and 11.1 and secondary windings 6.2 and 11.2, respectively.

The load element 10 included in the Converter may also not be included in it.

Beginning of transformer windings in FIG. 1 are indicated by a dot.

Regarding the DC bus 25 and 26, a chain of series-connected first and second capacitors 1 and 2 and series-connected first and second transistors 3 and 4 are connected in parallel to the current controlled circuit. The inputs of the primary winding 5.1 of the current transformer 5 are the converter control inputs 23 and 24. 11th voltage. The end of the first and the beginning of the second secondary windings 5.2 and 5.3 of the current transformer 5 are connected to each other and to the connection point of the emitter of the first 3 and the collector of the second 4 transistors. The end of the second secondary winding 5.3 of the transformer 5 is connected to the end of the primary winding 27.1 of the current sensor 27, the beginning of which is connected to the beginning of the primary winding 6.1 of the first output transformer 6,

the beginning of the secondary winding 6.2 of which is connected through a directly connected first diode 7 and a smoothing filter 9 with the first input of the load element 10, the second input of which is connected via a common bus (Fig. 1 "housing) with the end of the secondary winding 6.2 of the first output transformer 6. The beginning of the third the secondary winding 5.4 of the transformer 5 is connected to the emitter of the second transistor 4 and to a negative input voltage bus 26, the positive bus 25 of which is connected to the collector of the first transistor 3.

The end of the primary winding 11.1 of the second output transformer 11 is connected to the end of the primary winding 6.1 of the first output transformer 6. The beginning of the primary winding 11.1 of the second output transformer 11 is connected to the connection point of the first and second capacitors 1 and 2 and to the first terminal of the third capacitor 12, the second terminal of which is connected with the connection point of the emitter of the first 3 and the collector of the second 4 transistors. The beginning and end of the secondary winding 11.2 of the second output transformer 11 are respectively connected through a directly included second diode 8 to the input of the smoothing filter 9 and to the common converter bus.

The anode and cathode of the third diode 15 are connected respectively to the emitter and collector of the first transistor 3, and the anode and cathode of the fourth diode 16 are connected respectively to the emitter and collector of the second transistor 4.

The beginning of the first secondary winding 5.2 of the transformer 5 is connected through a parallel connected fourth capacitor 13 and connected in series with the directly connected fifth and sixth diodes 17 and 18 to the base of the first transistor 3. The common connection point of the fifth and sixth diodes 17 and 18 is connected through a directly connected seventh diode 19 to the collector first transistor 3.

The end of the third secondary winding 5.4 of the transformer 5 is connected through parallel connected fifth capacitor 14 and connected in series directly connected to the eighth and ninth diodes 20 and 21 with the base of the second transistor 4. The common connection point of the eighth and ninth diodes 20 and 21 through directly connected to the tenth diode 22 is connected to the collector of the second transistor 4.

All elements used in the voltage converter are standard and are widely used in industry. They are also very interchangeable in type, depending on the required capacity of the converter and its other characteristics.

The voltage transducer operates as follows.

When applying the control meander to the control inputs 23 and 24 (see diagram “a in FIG. 2), using the current transformer 5, the transistors 3 and 4 are switched alternately. The base current of the switched-on transistor is maintained using the current transformer 5 proportional to the collector current.

2L (1 {(2CH) b

Let, for example, at the time tl (see diagram "b in figure 2), turn on the transistor 4. Its current rises according to the sine law in the time interval tl -t2. At time t2, the winding 5.1 of the transformer 5 is short-circuited using a control circuit forming a control square wave (the control circuit is not shown in FIG. 1 as a matter of principle), as a result of which the collector current of transistor 4 rapidly decreases to zero. However, the voltage at the collector of the transistor increases slowly, because the capacitor 12 is recharged by the current flowing through the windings 5.3, 27.1,6.1 and 11.1 of the transformers 5, 27, 6 and 11 (see diagram "g in figure 2). By time t3, this voltage reaches a constant input voltage Ep, increased by a small voltage drop across the open diode 15. This diode continues to be open until time t4, when the current flowing through the circuit becomes zero: windings 11.1, 6.1, 27.1, 5.3, capacitor 12. Despite the fact that the input voltage from time t2 to time t4 is opening for transistor 3, the latter remains closed due to the action of magnetic coupling: winding 5.3 - winding 5.2, because the current during the time t2-t4 passing through the winding 5.3 forms a negative bias at the transition "emitter-base of the transistor 3.

At time t4, the current through winding 5.3 decreases to zero and the transistor 3 opens the control signal. The collector current of this transistor increases according to the sine law until time t5, when it drops sharply to zero due to shorting of winding 5.1 (see diagram “in FIG. 2). The voltage at the collector of transistor 4 is slowly decreasing, as the capacitor 12 is recharged by the current flowing through the windings 5.3, 27.1, 6.1 and 11.1 (see diagram "g in figure 2) and by time 16 reaches a negative value equal to the voltage drop across the open diode 16, which continues to beat open until time 17, when the current flowing through the circuit becomes equal to zero: windings 5.3, 27.1, 6.1, 11.1, capacitor 12. Despite the fact that the input voltage from time t5 is opening for transistor 4, the latter remains closed due to the action of magnetic coupling: winding 5.3 - winding 5.4. At time t7, the current flowing through winding 5.3 decreases to zero and the input signal again opens transistor 4, etc. Transistors 3 and 4 are periodically switched.

Each half-wave one of the transformers 6 and 11 operates as an output transformer, transferring energy through diodes 7 and 8 and a smoothing filter 9 to the load element 10, and the other transformer as the inductance of the resonant circuit together with capacitors 1, 2 and 12. The voltage at the common connection point of the capacitors 1 and 2 in shape is close to a sinusoid (see diagram "e in figure 2).

under the action of the current, the cores of the capacitor 12 are transferred through the primary winding 27.1 and the secondary winding 27.2 of the current sensor 27, the transistor 27.3 is maintained open. As a result of this, the current flowing through the diode 27.5 and the additional winding 5.5 of the current transformer 5 prevents the formation of the potential opening on the basis of the transistor 3 thereof. The blocking of this transistor continues until it becomes equal to the normal current of the resonant circuit.

Similarly, when the transistor 4 should not open in the time interval t5-t7 (see Fig. 2) (in this case, the recharge current of the capacitor 12 passing through the primary winding 27.1, in contrast to the previous case, has the opposite direction), the transistor 27.4 is kept open, as a result, the current flowing through the diode 27.6 and the additional winding 5.5 of the current transformer 5 prevents the formation of the potential opening on the basis of the transistor 4 thereof.

In contrast to the prototype, due to the presence of the capacitor 12 in the inventive converter, which at time intervals t2-t4 and t5-t7 is recharged through the winding 5.3, and in addition to this through the current sensor 27 with the effect through the winding 5.5, a delay of harmful (premature ) turn on transistors 3 and 4. This allows you to significantly simplify the control device, which instead of a complex meander with blocking pauses at intervals t2-t4 (t5-t7) is the simplest meander shown in the diagram "a of Fig. 2, and to increase the efficiency of the converter.

In addition, at time intervals t3-t4 and t6-t7, due to the presence, in contrast to the prototype, of diodes 15 and 16, there is a shortest path to the current, which also increases the efficiency of the converter.

Posted by: 77 // А.Ю. Goncharov.

Claims (1)

A voltage converter comprising, in parallel with respect to two DC busbars, a chain of series-connected first and second capacitors and series-connected in a current-controlled circuit of the first and second transistors, a first current transformer, a first output transformer, first and second diodes, a smoothing filter, and the terminals of the primary the windings of the first current transformer are used as the control input of the voltage converter, the end of the first and the beginning of the WTO a swarm of secondary windings of the first current transformer are connected to each other and to the connection point of the emitter of the first and collector of the second transistor, the end of the second secondary winding of the first current transformer is connected to the beginning of the primary winding of the first output transformer, the beginning of the secondary winding of which is connected through a direct-connected diode and a smoothing filter to the first output for connecting the load, and the end of the secondary winding of the first output transformer is connected to the second terminal for connecting the load and with a common oh, the beginning of the third secondary winding of the first current transformer is connected to the emitter of the second transistor and to the negative DC input bus, and the collector of the first transistor is connected to the positive DC input voltage bus, characterized in that the second current transformer, the second output transformer, the third are introduced into it and a fourth transistor, three capacitors and ten diodes, the end of the primary winding of the second output transformer being connected to the end of the primary winding of the first output transformer rmator, the beginning of the primary winding of the second output transformer is connected to the connection point of the first and second capacitors and to the first terminal of the third capacitor, the second terminal of which is connected to the connection point of the emitter of the first and collector of the second transistors, the beginning and end of the secondary winding of the second output transformer are respectively connected to the first output for connecting the load through a direct-connected diode and a smoothing filter and with a second terminal for connecting the load, the anode and cathode of the third diode are connected respectively to the emitter and collector of the first transistor, the anode and cathode of the fourth diode are connected respectively to the emitter and collector of the second transistor, the beginning of the first secondary winding of the first current transformer is connected through a parallel connected fourth capacitor and series-connected directly connected fifth and sixth diodes to the base of the first transistor, point connection of the fifth and sixth diodes through a direct-connected seventh diode connected to the collector of the first transistor, the end of the third secondary the slots of the first current transformer are connected through a fifth capacitor connected in parallel and the eighth and ninth diodes connected in series to the base of the second transistor, the eighth and ninth diodes are connected through the tenth diode directly to the collector of the second transistor, the primary winding of the second current transformer is connected in series anywhere in the resonant circuit consisting of series-connected primary windings of the first and second output transformers, the second in toric windings of the first current transformer and the third capacitor, the primary winding of the second current transformer included in turn with the windings that make up the resonant circuit, the beginning of the secondary winding of the second current transformer is connected to the bases of the third and fourth transistors, and its end to the emitters of these transistors and with the end of any of the secondary windings of the first current transformer, while the beginning of the used winding is connected through a directly connected eleventh diode to the collector of the third transistor and through the twelve-way reverse-connected diode with the collector of the fourth transistor, and the end with the connection point of the emitters of the third and fourth transistors, the third and fourth transistors having npn and pnp type conductivity, respectively.