SU966828A1 - Method and apparatus for converting ac voltage into dc voltage - Google Patents

Description

(i;) METHOD FOR CONVERSION OF AC VOLTAGE TO ACCURATE DC TURNING A VOLTING VEHICLE AND A DEVICE FOR ITS IMPLEMENTATION. including the operations of changing the instantaneous value of an initial alternating voltage with the help of a transformer, phase shift of one of the multiplied voltages with the help of phase shifting lev els chains and device selection absolute value of alternating voltage isolation constant and variable components in this way to increase the value of the D.C. voltage reduced by the value of variable moiety doubled its Toth hour. However, the phase shift operation necessitates the use of cumbersome phase shifting devices, resulting in a large dynamic conversion error under the pulsed nature of the load, and if it is necessary to obtain several galvanically unrelated DC voltages, installation of so many cumbersome phase shifters is required. In this case, the operation of separating the absolute value separately for each of the changed variable voltages requires the use of a large number of power rectifying elements. It is also known a device for converting alternating voltage into a constant voltage containing a transformer. The primary winding of which is connected to the input terminals, and the secondary winding contains an additional winding which is connected to the load through a controlled semiconductor device. G. Using the device, a conversion method is implemented, which includes the operations of changing the instantaneous voltage of the distillation voltage, extracting the absolute instantaneous values of alternating voltage 2. The operation of overlapping the absolute values of alternating voltages requires the use of controlled keys on the low voltage side, each for generated DC voltages need their own key. Key control; can be performed on a thyristor, but this requires complex artificial switching circuits; its implementation on the transistor is difficult due to the switching of large currents equal to the load current; performing it on a controlled thyristor is also confused, since it requires the formation of control pulses of different polarity with the same polarity of the alternating voltage and due to the small current gain coefficients, such devices for closing. These circumstances do not allow to obtain high specific energy conversion rates; The purpose of the invention is to improve the specific energy characteristics of the transformation. This goal is achieved by the fact that, according to the method of converting an alternating current voltage to a direct current voltage involving the operation of changing the instantaneous value of the initial alternating current voltage, extracting the absolute value of the alternating current voltage, additionally performing the operation of determining the zero, minimum and the maximum values of the initial voltage of the alternating current, the operation of dividing each half-period of the initial voltage of the alternating current into time intervals, symmetrically located relative to the moments of transition of this voltage through zero, maximum and minimum values of the initial alternating current voltage, the operation of changing the instantaneous values of the initial alternating current voltage to a certain number (K) of times at each of the selected time intervals, the operation of addition in the manner of AC voltage at all time intervals and then the operation of extracting the absolute value of the AC voltage, while the duration of the time interval in - and the values to which the instantaneous values are varied voltage AC line current are determined from the Word arcsin) 3 f Kj | sin4 | - Jd f; arcsln-zarcsin Y "resin 4iUi -) iJ () -. rcsifl "resin fji--) rcsin" n jigjoifl-J; itf ((sin4 | -) i JI G JV o rcs n-rrp where / k ... K | .. "K |,.,., - respectively, the values at which the instantaneous values of the alternating current voltage and the duration of the allocated time intervals vary from the first additional. This method can be implemented by the device for converting the alternating current voltage into a direct current voltage a key, a transformer, one of the terminals of the primary winding of which forms the first input terminal, a rectifier connected to the secondary winding of a transformer Pa, the filter connected to the output of the rectifier and forming the output pins, into which the time interval selector, the control switchboard, the additional control keys and the additional transformers, each of which one output of the primary winding connected to the first input terminal, are entered, each of The other terminals of the primary winding are connected to the first terminal of the controlled key, the second terminals of all the controlled keys are combined to form the second input terminal, the combined third terminals of the controlled keys of the connected The control output of each of the control keys is connected to the corresponding output of the control switch, the input of which is connected to the output of the time selector connected to the input terminals, the secondary windings of all trans (L o (emators are connected according to consistently and

connected by free leads to the input of the rectifier.

FIG. Figure 1 shows the voltage plots (a, b, c, d, e) for the case of splitting a half-period of alternating voltage into two time intervals; FIG. 2 is a schematic diagram of an apparatus for carrying out the method; FIG. 3 embodiment of the time slot selector circuit.

The value of the method is explained in Fig. 1, where voltage plots are shown for the case of dividing half perio 1a into two time intervals: a is a sinusoidal alternating voltage (the allocated time interval is shaded with boundaries from -h to h; the remaining time interval from h to J7 - F; 5 - alternating voltage after the addition operation on the secondary windings; 6 - allocated, the absolute value of the initial voltage of the alternating current, and - selected constant component; i. - selected variable component; - increased in scale by t absolu The total value of the alternating voltage; U is the selected post component; ... 5 the average values (area) of the half periods of the selected variable are constituted.

The sequence of operations of the method of converting the next | a,

The half-cycle of the alternating current voltage (fig. Let is divided into an integer number of time intervals with boundaries symmetrical with respect to the angles | h 0 ° and h - l / 2; the first and last sections contain respectively angles h q q and h J7 / 2. Intermediate time intervals between the first and the last consists of two sections, indicated by dash-dotted lines in the let figure and symmetrically located with respect to the angle 4 0. Then the operation is performed to change the instantaneous value of the AC voltage to a certain number (K) times after The resulting voltage for the two intervals is shown in Fig. 16, After that, the operation of extracting the absolute value of the voltage from the instantaneous values of the accumulated AC voltages is carried out. Then the variables (Fig. 1) and the constant (U on Figures 1c and 15) are components of the extracted absolute values of the AC voltage.

The values of K and the duration of the H time intervals n should be chosen from the conditions not only of the equality of the constant and variable components on the individual time intervals allocated when extracting the absolute value, but also the equality of the positive and negative values of the function / sin on each segment, those. these conditions can be written as (from FIG. 13) 5 54; 5 Sj; 55 5g. However, the first two conditions are identical in terms of the composition of the variables. Then these conditions (without the first and last), for example, for an item, will be written arcsin-С /

.K, j ((Sinc / | -fJd -K j (lsincfl. AresinCh

KI

(, s 4 | -l -) (| sin fbljc3 -.

arcsin f

in (i-i)

arcsin JI-:

arcsin -r- KI K, J (lS l-fJsCf Kj | ()

oircsio - KI

I /.

I /.

Ka-ITT

where - -

Umi

amplitudes given

to the output voltage of ac at Pl. and;

Sin is the average value of the absolute value of the AC voltage in the first and second intervals, respectively.

From the compiled system of equations it can be seen that it has three unknown KI; KI ;. Since by definition

n, 1 - Ch., with n 7 2 each new

Claims (2)

The plot gives 2 unknowns (F and K) and two equations: the condition of equality of the areas of the variable components (negative and positive with respect to u) and the condition of equality of one of these areas of the variable component of the next (previous) section. Thus, similarly, the conditions for the front of them can be found at variable intervals and% -v .-. (.) Values and Kx.,. Kn So, for n 2; K) 1 1.18, V 22.5 °. For and 3; K 16.7; to 2.23; Кз 1, FIG. 2 shows an apparatus for carrying out the method. The device contains the first transformer 1, which carries out the operation of changing the instantaneous value of the initial voltage of the alternating current in the first interval at its mcno time, the second transformer 2, which performs the indicated operation in the second interval, diodes 3-6 of the rectifier, performing the operation of selecting the absolute value of the alternating current voltage (fig. 16), the filter 7, which performs the operation of extracting a variable component on its inductance (Fig. 1b) the absolute value and the operation of extracting the filter capacitance and the load the remaining absolute value (U in Fig. 1c 1E), control keys 8.1 and 9.1 with pins 8.2, 8.3, 8., 8.5 and 9.2, 9.3 9., 9.5, switch 10 control signals, selector 11 time intervals. Transformers 1 and 2 by one of the outputs of the primary windings are connected and connected to the first input terminal. The secondary windings are connected in series and free terminals are connected to rectifier diodes 3-6. The output of the rectifier is connected through a filter 7 to the load shown in FIG. 2 dotted line. The other terminals of the primary windings of transformers 1 and 2 are connected to the first terminals 8.2 and 9.2 of the controlled keys 8.1 and E.1. The second pins 8.3 and 9.3 of the controlled calls are connected to the second input pin. Third pins 8.4, 9. managed keys 8.1, 9.1 are connected to the first input pins. The control pins 8.5, 9.5 of the control keys are connected to the outputs of the switch 10 of the control signals, and its input to the output of the selector of 11 time intervals, the input of which is connected to the input pins. The device works as follows. Each half-period of the initial AC voltage is divided into at least two time intervals from - H to H and from H to | -CH (Figs. 1a .. respectively, shaded and non-hatched areas. This partitioning in the device is carried out by anti-phase control keys 8.1 and 9.1, so that in the first interval the outputs 8, 3, 8.2, and 9, 9.2 are closed. Thus, in the first time interval, the AC voltage is applied to the primary, transformer 1 transformer 1, and the primary winding of transformer 2 is short-circuited. This mode lasts until time point H, in which control keys 8.1 and 9.1 change t its balance, closure conclusions 8.i, 8.2, and t kzhe 9.3, 9 "2. From this moment (second time interval), the primary winding of transformer 2 is connected to the AC voltage source, and the primary winding of transformer 1 is shorted. As a result, the first AC voltage is applied to the primary winding of transformer 1 , indicated by the hatching in Fig. Icj, and in the second interval, the entire AC voltage is applied to the primary winding of the transformer 2. Then, the operation is performed by changing the instantaneous voltage value alternately on current in each interval on their K value - the first interval - by a factor of transformer l-K / ,, in the second interval - the transformation ratio of the transformer 2-K2. Then the operation is performed by adding the instantaneous values of the alternating current voltage changed in its number K using connected secondary windings of transformers 1 and 2 connected in series according to the first voltage interval on the secondary winding of transformer 1 is equal to and the secondary winding of transformer 2 is equal to Oh, her resistance is close to Oh, since the primary winding is shorted. Thus, the voltage at the free terminals of the secondary windings of transformers 1 and 2 is equal to the first interval. Similarly, this voltage is equal to the second interval. As a result, a free voltage is formed at the output terminals of the secondary windings, the diagram of which is shown in Fig. 16. After the addition operation, an absolute value is taken to extract the absolute value of the complex AC voltages. It is carried out using rectifier diodes 3-6. As a result This operation at the output of the rectifier and the input of the filter 7 forms a voltage, the diagram of which is shown in Fig. 1c. To split the half-period into three time intervals, it is necessary to introduce one more transformer connected by one output of the primary windings to the corresponding combined leads of the same windings of transformers 1 and 2, and the second to the third control key with the corresponding connection of its four terminals. After the extraction of the absolute value, the operation performs the separation of its constant and variable components. This operation is performed using a filter 7. On a series-connected with a load element of the filter-inductance, a variable component of the voltage is selected, and on a parallel element connected to the load The filter — capacitance — constant is a component of this voltage. The time interval is determined by the selector 11 time intervals, it can be performed, for example, according to the amplitude selector scheme, as in the case of two time intervals shown in FIG. 3. At the moments when the instantaneous value of the variable GO voltage value, corresponding to time, is reached, the zener diode penetrates and the difference between the input voltage and the stabilization voltage is applied to the resistance. The selector 11 can be made according to the time selector scheme, i.e. in the form of a counter generating signals arriving at the switch at times V The switch 10 of control signals can be executed according to any scheme, for example, according to the scheme of a counting ring. For the case of two time intervals, this is, for example, an optoelectronic trigger. To supply many loads, it is necessary to introduce additional (in terms of number of loads) secondary windings of transformers, rectifiers and filters (not shown in Fig. 2). However, for any number of output DC voltages, the number of controllable keys remains constant — corresponding to one number of allocated time slots. Thus, in the described technical solution, an improvement in specific energy characteristics is achieved, expressed in reducing the weight and size parameters of controlled keys, the number of valves, and also a significant decrease in power dissipation, which increases efficiency. Claim 1. A method of converting an alternating current voltage to a direct current voltage, including the operations of changing the instantaneous value of the initial alternating current voltage, extracting the absolute value of the alternating current voltage, so that the purpose of improving the specific energy characteristics, the additional (the operations of determining the zero, minimum and maximum values of the initial voltage of alternating current, then the additional operation of splitting each half-period and the initial voltage of the alternating current is at time intervals symmetrically located with respect to the moments of transition of this voltage through zero, maximum and minimum values of the initial alternating current voltage, then the operation of changing the instantaneous values of the initial alternating current voltage to its specific number (K) times on each of the allocated time intervals, then the additional step of adding the values of the alternating current voltage thus changed at all time intervals and then perazim isolating absolute value of the AC voltage, wherein the duration of the time intervals and the value V, in which vary the instantaneous values of the AC voltages are determined from the conditions. . (() i arcsin-j drosindrcsln к К, „j () .j (,) C rCSin rp-i "Resin PG- arcain H 5 () L (.JJ n-1 arcsin where K, .. K. ..K.CH.-. ... f are, respectively, the quantities at which the instantaneous values of the alternating current voltages and the duration of the time intervals from the first sub-y change. 2. An apparatus for carrying out the method of converting an alternating current voltage to a direct current voltage according to claim 1, comprising a control key, a transformer, one of the terminals of which is the primary winding, forms the first input terminal, a rectifier connected to the transformer secondary winding filter connected to the output of the rectifier and forming the output pins, which are related to the fact that the device has a time selector, a control switch, additional control keys, and Transformers, each of which is connected to the first input terminal by one output of the primary winding, each of the other outputs of the primary winding is connected with the first output of the controllable key, the second outputs of all the controllable keys are combined to form the second input output, the combined third outputs of the controllable keys are connected to the first input pin, and each control pin of the controlled keys is connected to the corresponding output of the switch of control signals, the input of which is connected to the output of the time selector at the server fishing connected to the input terminals, the secondary windings of the transformers are connected in series according to u-free terminals connected to the input rectifier. Sources of information taken into account in the examination 1. The patent of Great Britain f 1072508 cl. And 2 F, 1967. 2. The patent of Germany No. 1t67 37, class. 21 d 1-72 / 02, 196. Phie.1