SU1336175A1 - D.c.voltage regulated converter - Google Patents

Abstract

The invention relates to converter equipment and can be used in the development of secondary power sources. The purpose of the invention is to simplify the implementation of balancing the operation of the converter. The converter contains a power conversion and control channel and a control channel. The presence of one control channel ensures the balancing of the operation of the adjustable converter during the entire interval of action of the overload, eliminating the excess current in each of the inverter switching arms. 2 Il. with with O5: 71

Description

The invention relates to converter equipment and can be used in the development of power supplies.

The purpose of the invention is to simplify the implementation of balancing the operation of the converter.

FIG. 1 shows a functional diagram of an adjustable converter; in fig. 2 - timing diagrams, according to the principle.

The adjustable converter comprises a power channel 1 for converting and regulating electric energy and a channel 2 for control. The power channel for the conversion of electrical energy contains a primary source 3 of electrical energy, an inverter 4 made of a push-pull power amplifier 5 and a transformer 6, for example, with a midpoint (in the general case, the power part of the inverter can be performed using any of the known push-pull circuits), the rectifier with filter 7, load 8.

The control channel 2 consists of a 9-clock pulse generator, a pause length generator 10, a sawtooth voltage generator 11, a pulmonary modulator 12, an adjustment node 13 that balances an L5 flip-flop 14, two matching amplifiers — the first 15 and the second 16, two, selectors - the first 17 and the second 18, the frequency divider 19 into two, the threshold element 20, / 5-trigger protection 21, one-shot 22, current sensor 23.

Timing diagrams of voltages and currents at the respective elements of the adjustable converter are shown in FIG. 2: a - at the generator output 9 clock pulses; b - at the output of the imager 10, the pause duration; in - at the second input of the first selector 17; d - at the inputs of the pulse-width modulator 12; d - at the output of the pulse-width modulator 12; e - at the output of the threshold element 20; W - at the output of the protection trigger 21; h - at the output of the one-shot 22; and - at the output of the balancing trigger 14; k - at the output of the first selector 17; l - at the output of the second selector 18; m is the collector current of the power transistor of the push-pull power amplifier 5, controlled by the output signal of the first selector 17, is the current of the first inverter arm; n is the collector current of the power transistor of the push-pull power amplifier 5, controlled by the output signal of the second selector 18, is the current of the second side of the inverter; o - voltage at the output of the transformer 6.

The generator 9 clock pulses output connected to the input of the imaging unit 10 the duration of the pause. The output of the specified driver 10 is connected to the inputs of a frequency divider 19 for two and a sawtooth voltage generator 11, as well as to the first inputs of the first 17 and second 18 selectors, S-inputs of the trigger - protection 21 and balancing 14. The selectors 17 and 18 are fifth inputs connected to the output of the balancing trigger 14, the third inputs to the output of the pulse-width modulator 12, the second inputs from the first selector 17 to one, and the second selector 18 to the other output of the splitter 19 frequency two. Single input 22 is connected to the output of the protection trigger 21 and to the fourth

0 inputs of the selectors 17 and 18, and the output to the / -input of the balancing trigger 14. The pulse-width modulator is connected to one output of the generator 11 of the saw-tooth voltage, and the other to the output of the control unit 13. The outputs of the selectors 17 and 18 are connected respectively through the matching amplifiers 15 and 16 to the control inputs of the push-pull power amplifier 5. The power circuit of the specified amplifier 5 is connected to the sensor 23

0 current, the output of which is connected to the input of the threshold element 20, the output of which is connected to the / -input of the protection trigger 21. When operating in the stabilization mode, the output of the load 8 is connected to the control unit 13.

5 Adjustable Converter works as follows.

The power channel 1 converts the electrical energy of the primary power source 3 from one level (quantity and quality) to another, required for load function 8. The level of electrical energy supplied to the load 8 is controlled by a two-stroke inverter 4 using the principle of pulmonary modulation. The control signal of the specified inverter is generated by control unit 2.

The period of operation (switching, conversion) of the inverter 4 is determined by the period of the output signal (Fig. 2 a) of the generator 9. The shaper 10 to the front of the specified signal produces pulses of duration T (Fig. 2 b). The maximum possible time tmax of the open state of the power switching transistors of the amplifier 5, i.e., imax G / 2-Tn, is shortened by the duration of Tp. The impact of the output signal of the shaper 10 on the input of the saw generator 11 provides at the output of the last a sawtooth voltage Un (t) (Fig. 2 g). In the general case, the shape of the sawtooth voltage may be different, for example, equilateral, and the input

 The saw generator 11 is connected to the output of the generator 9. The output signals of the frequency divider 19 are two anti-phase (one of them is shown in Fig. 2c), their period is equal to two periods of the generator 9 output signal (two frequency divider 19 can be used trigger in counting mode). The impact of these antiphase signals on the second inputs of the selectors 17 and 18 ensures that a spur-modulated signal (Fig. 2 e) of the modulator 12 in the time interval corresponding to high levels of the splitter signals passes through their outputs (Fig. 2 k, l). 19 frequencies for two.

The high level of the output signal of the modulator 12 corresponds (Fig. 2 e) to the excess of the signal Uy (t) of the control unit over the signal And n (t) of the saw generator 11 (Fig. 2 g). The high levels of the output signals of the selectors 17 and 18 correspond (Fig. 2 to l, respectively) to the simultaneous presence of high voltage levels at all inputs of the selectors.

In the absence of overcurrent at the output of the threshold element 20, a low voltage level is present (Fig. 2e). In this state, the protection trigger 21 - a high level of the output voltage (Fig. 2 g - is determined by the effect (with period T) of the output signal of the driver 10, namely its cut-off 1/0 difference. The same signal (Fig. 2 b) determines the high voltage level at the output of the balancing trigger 14. For example, the output of the selector 17 is present in the interval / 0 + 7 positive pulse (Fig. 2k) with a duration during which high levels are simultaneously present at all inputs (Fig. 2 b, u, d, c, g). So, in the absence of overcurrent mode conversion and regulation of electrical energy is determined by the ratio of the signal levels of the control unit 13 and the generator 11 of the saw iln (t) (Fig. 2 g). When operating in the stabilization mode lJn (t is a function of the voltage (current) in the load circuit 8 (on Fig. 1 shows this mode by the dashed line linking the load 8 and the node 13).

In the overcurrent mode, the voltage 11 (1 at the output of the sensor reaches the voltage Uon (t) of the threshold element and a high voltage level is formed at its output. Suppose that this situation occurred at time ti (Fig. 2, plots n , e). At the front of the output signal (Fig. 2e) of the threshold element 20, the protection trigger is set to a low voltage level (Fig. 2 g), which persists until time 03, i.e., before the impact (cut) of the output signal shaper 10. The presence on any of the inputs of the selectors 17 and 18 low ur Aries provides a low level at their outputs. As a result, at the output of the selector 18, the duration of the positive pulse is reduced to tui tz- / 02-t "(in the absence of an overload, the duration of the control signal is determined by Uy {t) and Uii. (t) and corresponds to t uy , Fig. 2, l, o).

On the difference of 1/0 of the output voltage of the protection trigger 21, the one-shot 22 forms (as shown in Fig. 2) pulses of duration. pus K) T / 2 (as a single vibrator, Gmpgy can be used, for example, waiting: mu, 1t11H11p- rator). The output slice (Fig. 2h) of the single vibrator 22 sets the output of the balancing trigger 14 to a low voltage level, which is maintained until time point 04 (Fig. 2 and), i.e., until the output signal is applied (cut) 10 (Fig. 2 b). The presence of a low voltage level at the fifth entrances. The selectors 17 and 18 ensure low voltage levels at the time interval from / 3 + T g to / 04 (Fig. 2 к, л). As a result, the windings of the transformer 6 are provided with symmetric,

 offset rectangular pulses (Fig. 2 o) tLi duration shifted by Gg. If in the following periods of operation, overcurrent does not occur, then at the outputs of the flip-flops 21 and 14, high levels of voltage are obtained (Fig. 2, solid lines, respectively, diagrams, and). The conversion mode is determined by Yiwu (.) And L n (/). When an overcurrent occurs in the first shoulder of the inverter (Fig. 2, plot m), for example, at time / s (the indicated dotted mode of operation corresponds to the dotted lines of the time diagrams (Fig. 2), while we assume that this overload occurred again , taking into account the overload at time / 2 (Fig. 2, plot n), and the one-shot has not yet completed the formation of a positive impulse (Fig. 2 h), since the protection trigger 21 is set at time tz (Fig. 2, plot a) at a high level of output voltage, the front of the output signal of the threshold element At the moment of time overload (Fig. 2, plot e), the trigger sets the trigger 21 to a low level (Fig. 2, dashed line). This in turn sets (resets) the single vibrator 22 at the time / s to the state corresponding to time t, i.e. from moment tz, the one-shot one-shot begins to form a pulse with duration Gg. At time point Gg, the cut-off output signal of one-shot 22 (Fig. 2) sets the balancing trigger 14 to a low voltage level, which is maintained before

5 of the time point os (Fig. 2 and) affecting its first input of the signal cutter of the imaging unit 10 (Fig. 2 b). As a result, the occurrence of high levels of voltages at the outputs of the selectors 17 and 18 is eliminated over the time interval from to toz.

five

0

This prevents the passage of electrical energy from the primary source 3 of the power supply to the load 8. In this case, the windings of the transformer 6 of the inverter 4 are formed by shifting rectangular C pulses of equal duration / „3 (plot O, fig. 2) by Tr.

Thus, protection against overcurrent of switching current is implemented in each of the half-periods of switching. In this case, the balancing of the operation of the adjustable converter during the entire range of action of the overload is ensured, and the excess current in each of the inverter switching legs is eliminated.

Claims (1)

Invention Formula An adjustable DC voltage converter containing an output rectifier with a filter connected to the output transformer of a push-pull inverter, the control inputs of which are connected to the outputs of the two pulse selectors of the control unit, which is composed of a clock generator, which is connected via a matching amplifier to the input of the sawtooth generator, the input frequency divider for two, S-inputs / 5-triggers of protection and balancing and the first inputs of pulse selectors, the second inputs of which are connected to the corresponding outputs of the frequency divider, and the third - with the output of a pulse-width modulator, the first input connected to the generator output the sawtooth voltage and the second to the output of the control unit, with the I-input of the protection trigger connected through a threshold element to the current sensor, and the output to the fourth input of the first selector and the input of the one-vibrator, the output of which is connected to the I-input three balancing gate, with output connected to the fifth input of the first selector, characterized in that, in order to simplify the implementation of balancing, the fourth input of the second selector is connected to the output of the protection trigger, and the fifth input to the output of the balancing trigger. 22 14, 1b but toil Hi. taz ito -m L i / l g to5 tOB