SU1068715A1 - Method and device for stabilizing transistor dc voltage converter voltage - Google Patents

Abstract

1. A method of stabilizing the voltage of a transistor converter of a simple voltage with a reverse turning on of a diode, an inductor and an output filter at which the transistor is turned on at regular intervals of time, the output voltage of the converter is measured, compared to a reference voltage, amplified by the error signal, using it as a reference voltage, form at least one controlled voltage, compare it with the reference voltage, and turn off the transistor at the moments of their voltage a, characterized in that, in order to improve the quality of stabilization of the output voltage / voltage of the converter with an extended range of load resistance, this basic controlled voltage is formed by summing two signals, the first of which is obtained by measuring the input voltage of the output filter, and second. - by converting the current of the power circuit of the transistor to voltage. 2. The method according to claim 1, characterized by the fact that an additional controlled voltage is generated from said second signal, which is compared with the reference voltage. 3. Method according to p. 2, o. This means that when the signal is reduced (the signal obtained as a result of the indicated measurement of the output voltage to a value less than the reference voltage, the third signal is influenced by which the current is converted into a voltage increasing the value of the additional monitored voltage. 00 4. A device for stabilizing a constant voltage containing a fixed frequency generator, a driver of control pulses of a power transistor, an amplifier SP of a constant current, one input of which is connected to the output of the output voltage sensor or transformed, and daugoy to the source of the reference voltage, and the first comparator, the first input of which is connected to the output of the direct current amplifier, and the second through the first diode to the output of the grounding device controlled voltage, with the mentioned amplifier, sensor, comparator, and reference voltage source being connected to the common bus of the circuit, 6 tons per second, with the aim of improving

Description

The quality of stabilization of the output voltage of the converter with an expanded range of load resistance changes, the driver of the main controlled voltage consists of a divider connected at the C -.BL-C input of the filter and a current transformer, the first winding of which is connected to the power circuit of the transistor of the converter and the second a nepBfcjM resistor is shunted and connected between the outputs of the mentioned divider and driver.

5. The device according to claim 4, characterized in that it is provided with an additional controlled voltage driver, made in the form of a full-wave rectifier connected to the third winding of the above-mentioned current transformer with a second output resistor / connected to one output terminal with a common bus bus terminal, and the other .- with the first input of the second comparator, the second input of which is connected to the reference voltage source, and the output through the first diode is connected to the second input of the first comparator, to which is also connected ithout second diode the output of the main controlled voltage.

6. A device according to claim 5, characterized in that the second resistor of the additional controlled voltage generator is shunted by a chain consisting of a transistor and a third resistor connected to its emitter circuit, the base of the transistor being connected to the said output voltage sensor of the converter.

one

The invention relates to electrical engineering and can be used in the source: power supply of communication equipment.

There is a method of stabilizing the output voltage of a transistor of a dc converter, in which a monitored sawtooth signal generated from the input voltage is compared to a dc signal and the power switch is switched when these signals are equal, and the magnitude of the dc signal is amplified equal to the amplitude value of the monitored signal at the minimum value of the input voltage 11.

This method cannot be applied without changes to a transistor converter with a reverse connection of a diode.

The closest to the invention is a method of stabilizing an output voltage of a transistor converter with a reverse voltage diode, choke and output filter, at which the transistor is turned on at equal intervals of time, the output voltage of the converter is measured, and compared with a reference voltage amplify the received error signal, using it as a test voltage, form at least one controlled voltage, compare it with aporilic voltage and turn off - anzistor at the moment of their equality 2J.

The disadvantages of this method are the low accuracy of voltage stabilization in the discontinuous current mode of the reactor, large overloads of the collector current of the transistor; switching on and short-circuiting a dc converter; longer duration of transients caused by a change in the load resistance.

A device is known for stabilizing an output voltage, a constant-voltage transistor converter containing 5 a master frequency generator of a fixed frequency, a driver for controlling a power transistor, and a comparator whose first input is connected to a reference voltage source and the second is connected to the output of a controlled voltage generator the comparator, the source / reference voltage and the controlled voltage driver are connected to the common bus of the circuit 33.

The disadvantages of this device are low static and dynamic accuracy.

Closest to the invention is a device for stabilizing the output voltage of a dc transistor converter, containing a master oscillator of a fixed frequency, a driver for controlling a power transistor, t a dc amplifier, one input of which is connected to the output of the sensor for the output voltage the converter and the other to the source

the first voltage, and the first comparator, the first input of which is connected to the output of the DC amplifier, and the second to the output of the main controlled voltage generator, said amplifier, sensor, comparator and source of the reference voltage are connected to the common bus of the circuit 4.

The disadvantages of the known device are low accuracy of voltage stabilization in the mode of intermittent current of the reactor, large spikes of the collector current of the transistor when the constant voltage converter is turned off and short-circuited, and the duration of transients caused by a change in load resistance is longer.

The purpose of the invention is to improve the quality of the stabilization of the output voltage of the converter 20 with an extended range of load resistance.

This goal is achieved by the fact that, according to the method of stabilizing the voltage of a 25 transistor converter, with a reverse connection of a diode with a choke and an output smoothing filter, at which (S1t transistor at equal time intervals, the output voltage of the converter is compared, with the reference voltage, amplify the received error signal using it as a reference voltage, generate at least one controlled voltage, compare it with the reference voltage at the moments of their equality, the main controlled voltage is formed by 40 summing two signals, the first of which is obtained by measuring the input voltage of the output filter, and the second by converting the current of the power circuit of the transistor to 45 stitching

In this case, an additional controlled voltage is formed from the specified third signal, which is compared with the reference voltage. Jq

When the signal obtained as a result of this measurement of the output voltage decreases to a value less than the reference voltage, a third signal is generated, 5 which affects the indicated conversion of current to voltage, increasing the value of the additional controlled voltage .

In addition, a device for stabilizing a constant voltage,. 6 containing a fixed-frequency driving oscillator, pulse-driving pulsers of the power transistor, a DC amplifier, one input of which is connected to the output 65

the output voltage sensor of the converter and the other to the reference voltage source, and the first comparator, the first input of which is connected to the output of the direct current amplifier, and the second through the first diode to the output of the driver of the main controlled voltage {mentioned 1 amplifier, The sensor, comparator, and reference voltage source j) are connected to the common bus of the circuit; a driver of the main controlled voltage, consisting of a divider connected at the input of the CLC filter and the current transformer, is inserted; orogo connected 1c tseptranzistora power converter, and the second - shunted by a first resistor and connected between the outputs of said divider and shaper nuoah.

At the same time, this device can be equipped with an additional controlled voltage shaper made as a half-wave rectifier current transformer connected to the third winding of the current transformer with a second output resistor connected with one output to the common bus of the circuit and the other to the first input of the second comparator whose second input is connected to the reference voltage source, and the output through the first diode is connected to the second input of the first comparator, to which is also connected via the second diode output of the primary controlled voltage generator. In addition, the second resistor of the additional controlled voltage driver can be connected by a chain consisting of a transistor and a third resistor connected to its emitter circuit, the base of the transistor being connected to the sensor of the output voltage of the converter .

FIG. 1 and 2 show temporal diagrams / 1 m, which explain the proposed method J in FIG. 3 is a diagram of the proposed device.

FIG. 1 and 2 denote the reference voltage 1 (,) voltage 2 at the input of the output filter (), switching-on times of the transistor T, switching-off times of the transistor t, the main controlled voltage 3, voltage 4 proportional to the current of the main circuit of the transistor (ig XR) , additional controlled voltage 5, converter t switch-on mode, steady state

 overload.

The diagrams in FIG. 1 correspond to a stabilization method in which the additional controlled voltage 5 does not depend on the magnitude of the output voltage, and FIG. 2 — at which the additional controlled voltage increases as the output voltage decreases below the reference voltage. Since the transistor current is converted to voltage as a rule / by means of active resistance, in further reasoning we assume that in order to form the main controlled voltage, the second signal is formed with the help of resistance R., and the additional controlled voltage - by resistance R FIG. 1 and 2 it is shown that switching off the transistor of the converter in switching on modes and significant current overload occurs at times when an additional controlled voltage equal to the voltage drop on the resistance R 2 (i ex 2 reaches the reference voltage (Upn) - In modes of small deviations of the input voltage and load current, the transistor of the converter is turned off at times when the reference voltage () reaches the main controlled voltage equal to the sum of the voltage drop In the first resistor and on the K-th part of the input to the voltage converter, made with a capacitive filter (K-Ugj ,,)., At the same time, when R f (IC,), the average values of the transistor and diode currents and the effective value of the reaction current the torus in the switching and overload modes is less than in the steady state operation, despite the low rate of decay of the diode current, as a result of this, the overvoltage of the voltage converter in the overload mode is eliminated and its operation reliability increases. In the absence of control of the voltage drop across the resistance R, the input current of the voltage converter could have reached excessively high values, disturbing the normal operation of the voltage converter. In the proposed method of stabilizing the converter voltage, the transistor is turned off at the time when one of the conditions E ..- t + t about 1 is fulfilled

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switching frequency of the transistor. Ku is the gain of the dc amplifier; voltage reference voltage source; control circuit power supply voltage; reference voltage; power supply voltage converter f voltage across the load; - transistor on time; -inductive winding of the reactor; - the initial value of the current of the transistor when it is next turned on, equal to zero in the discontinuous current mode; -resistance of current shunts; - proportional coefficients of input current and output voltage. We divide all terms of the equations by K. 1 -, oil 1 Р + К о -1 К L Suppose that in (1) the sum of the first x terms is 3% of the three terms at the maximum supply voltage and the rated value of the load current and that / Kg const and does not depend .- from the output voltage transformer. Let us consider how many prototypes the output pitch of the converter deviates with the diode turning on when the power supply pitch and load current are changed during operation in the continuous reactor continuous current modes. 1. Fully reset the load current. When reset (Current load to zero and second terms decreases zero. Therefore Ugj, increasing by + 3%. 2. Lowering the supply voltage to the reactor intermittent current (J.,). In this case 2-LI, assuming that decreasing the voltage E increases (or decreases) E-t by the constant f, Rj, L, then the voltage must increase simultaneously (or decrease), and ../, which is impossible, since K. in et, C, nst. Therefore, in this mode, the output voltage of the converter is invariant to a change in the supply voltage. 3. A decrease in the supply voltage when not The intermittent current of the reactor (ip) 0), 3 in this case, U c, (E - U ,,) c 4 - Equation () with (3) takes the following form K t Е 3 io -Kji: i 54; F K7 on (Assume that as E decreases, the t and t also decrease, and consequently, the second and third terms decrease. The first term increases, but cannot be greater than the sum of the 1st and 2nd terms at E E, the first (s) and the second (up the terms vary by no more than 1.% at their original value of 3%. At the same time, the third term (and gb, x) O clones by no more than 1%. . If we assume that as E decreases, txj increases and E-t. increases, then u should also increase, but this is impossible, since both + and +. const. If decreasing E t increases with Et, then Ug ,,, may decrease or increase and increase. Suppose that E Ets „.,. yg1% and and, 2%. V Then at Е Е ...... and, it can reduce m L. l f ith to approximately 0.5%, and., Increase by approximately 0.5% and Up, - by 1%. Consequently, in the continuous current mode of the reactor, the output voltage of the converter is invariant to a change in the supply voltage with a given degree of accuracy. When QP (Ugji,), then the accuracy of stabilization of the output voltage increases significantly compared to the case and n const. The proposed voltage stabilization method is essentially a combined stabilization method in two channels. Stabilizing the sum of voltages, one of which is proportional to the input current and the other to the output voltage, is the 1st channel of stabilization, and the correction of the reference voltage is the 2nd channel of stabilization. A change in the supply voltage causes a change in the rate of rise of the input current and the open time of the transistor during one period. A change in the load resistance also during one period leads to a change in the output voltage of the converter and the open time of the transistor. It is the two-channel system that, taking into account the above evidence, ensures an increase in the accuracy and speed of the control system. A device for carrying out the proposed method comprises a fixed-frequency driving oscillator, a driver 7 for controlling pulses of a transistor 8, a DC amplifier 9, one input of which is connected to the output of the sensor 10 of the output voltage of the converter, and another source 11 of the reference voltage,. and the first comparator 12, the first input of which is connected to the output of the DC amplifier 9, and the second through the second separation diode 13 to the output of the main controlled voltage generator, which consists of a divider 14 of the input voltage of the output C-LC filter 15 and the current transformer 16 . The first winding of the current transformer 16 is included in the power circuit of the transistor 8, and the second one is -shunned by the first re- sis-. The second input of the first comparator 12 is connected through the first separating diode 18 to the output of the driver of an additional controlled voltage, which consists of a second resistor 19 connected via rectifier 20 to the third winding of the current transformer 16, and the second comparator 21. The second resistor 19 shunted by a chain 22;, an emitter follower) consisting of a third resistor 23 and controlling a whole transistor 24, the base of which is connected to the output of an output voltage sensor 10. The power circuit of the converter consists of a transistor 8, droplets 25, a power diode 26 and an output CLC filter 15. All control signals are supplied to the common bus 27 to which one of the load terminals 28 is connected. The transistor 8 is turned on by pulses of the oscillator 6 through the driver 7, current through the first winding of the transformer 16 increases, which causes an increase in the voltage across the resistor 17 (Fig. 1). At the time when the voltages are equal at the first and second inputs of the comparator 12, the latter is transferred and switches the transistor 8 through the driver 7. Simultaneously with increasing voltage on the resistor 17, the voltage on the resistor 19 rises, compared at the input of the second comparator 21 with the reference voltage of the Zener diode 11. The excess of the additional controlled voltage over the reference voltage, which occurs during the starting and overload modes of the converter, causes the second comparator 21 to be transferred, then the first comparator 12 and, as a result, turning off the transistor 8. Thus, instantaneous protection of the transistor 8 against overloads is provided. Dp decrease: the collector current of the transistor 8 when starting the converter and the output voltage spikes of the converter connected with it parallel to the resistor 19 is turned on emitter follower 22, the input of which is connected to the sensor 10 of the output voltage. When starting, the voltage on the load 28 and, accordingly, at the output of the sensor 10 is zero, the transistor 24 is closed, and the voltage on the resistor 19 (Fig. 2) reaches the values at a lower value of the current through the transistor 8 than in the steady state cutting After the converter reaches the steady-state mode, the control transistor 24 is turned off and the voltage 19 reaches the voltage 19 and the transistor 8 is set at the current set point over the current. Thus, it is possible to provide the required element of the power circuit of the converter during the starts and overloads. . Technical and economic advantages of the proposed method of stabilizing the output voltage of the converter and the device for its implementation are to improve the quality of stabilization of the output voltage at a wide range of load resistance (the reactor operates in both continuous and intermittent current mode), increase the reliability of the converter. Improving the quality of output voltage stabilization is to improve the accuracy of stabilization, the speed of the control system, the stability of the control system. A change in the supply voltage causes a change in the rate of rise of the input current and the open time of the transistor during one period. A change in the load resistance also during one period leads to a change in the output voltage of the converter and the open time of the transistor. This ensures high speed control system. High stability is achieved by eliminating inductance control and filter capacitance C-L-C from the control loop by summing up with a voltage proportional to the input voltage of the input, and not at the output of the filter. High voltage stabilization accuracy is created by two control loops. The high reliability of the converter is ensured by limiting its input current in overload and on mode. In the absence of stringent requirements for output voltage pulsations C-L-C, the smoothing filter can be replaced with a C filter. In this case, the divider of the input. Voltage of the C-L-C filter and the high voltage sensor are connected in parallel. If necessary, galvanic isolation of the input and output voltages, the choke (transformer) can be made double-winding.

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Claims (6)

1. A method of stabilizing the voltage of a transistor DC-DC converter with a reverse diode, a choke and an output filter, in which the transistor is turned on at regular intervals, measure the output voltage of the converter, compare it with a reference voltage, amplify the received error signal using it as a reference voltage , form at least one controlled voltage, compare it with the reference voltage and turn off the transistor at the moments of their equality, I ayuschiys that, in order to improve the quality of the output HA stabilization. converter voltage with an extended range of load resistance, the specified main controlled voltage is formed by summing two signals, the first of which is obtained by measuring the input voltage of the output filter, and the second. - by converting the current of the power circuit of the transistor to voltage. 2. The method of pop. 1, they are distinguished by the fact that an additionally controlled voltage is formed from the indicated second signal, which is compared with the reference voltage. 3. The method according to p. 2, characterized in that when "reducing the signal obtained as a result of said measurement of the output voltage to a value less than said reference voltage, frr-. they generate a third signal, which affects the specified conversion of current into voltage, increasing the value of the additional controlled voltage. 4. A device for stabilizing a constant voltage, comprising a fixed-frequency master oscillator, a power transistor control pulse generator, a direct current amplifier, one input of which is connected to the output of the converter output voltage sensor, and the other to a reference voltage source, and a first comparator, the first input of which connected to the output of the DC amplifier, and the second through the first diode to the output of the main controlled voltage driver, the mentioned amplifier, sensor, omparator and a reference voltage source connected to the common bus scheme, ό n t h and a - 'w o f ES I that, with a view to seizing SU „„ 1068715 to improve the quality of stabilization of the output voltage of the converter with an extended range of load resistance, the driver of the main controlled voltage consists of a divider connected to the input of the C-.LC filter and current transformer, the first winding of which is included in the power circuit of the transistor of the converter, and the second shunted by the first resistor and connected between the outputs of the aforementioned divider and former. 5. The device according to p. 4, characterized in that it is equipped with a shaper of additional controlled voltage, made in the form of a half-wave rectifier connected to the third winding of the current transformer with a second output resistor connected to one terminal with a common bus · circuit, and the other · - with the first input of the second comparator, the second input of which is connected to the reference voltage source, and the output through the first diode is connected to the second input of the first comparator, to which is also connected of the second diode output controlled voltage generator core. 6. The device according to claim 5, characterized in that the second resistor of the additional controlled voltage driver is shunted by a chain consisting of a transistor and a third resistor included in its emitter circuit, the transistor base being connected to said converter output voltage sensor.