SU915186A1 - Simulator of dc voltage socrce with high internal resistance - Google Patents

Description

The invention relates to a power converter equipment and can be used in the development of devices that mimic the operation of constant voltage sources with high internal resistance, in particular solar cells.

Known simulators of solar cells, consisting of DC sources, shunt linear regulator, current sensor and functional, transducer, in which the current-voltage characteristics are obtained, close to the characteristics of the solar battery [1 ^.

The disadvantage of such simulators - low efficiency, large mass and size.

Also known are solar cell simulators', in which, in order to improve energy and mass-dimensional parameters, the power section is made as a series of conversion cells of current stabilizers connected to the load via decoupling diodes

2

and output-shunted keys, a linear regulator and a control circuit containing a switch, a current sensor, a functional converter and a comparison circuit ^

However, even in such simulators a significant power loss is generated on the control transistor, especially with a small number of converter cells. This reduces the efficiency of the simulator.

The closest in technical essence to the invention is a simulator of a solar battery [2].

The purpose of the invention is to increase the efficiency of the simulator.

This goal is achieved by the fact that in the simulator of a solar battery, consisting of a number of converter cells - current regulators, connected at the input to the power supply voltage, and at the output - to the load through the separation diodes

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four

shunted controlled keys, a regulating transistor, a commutator connected by its outputs with controlled keys, an input to a load current sensor, and a comparison circuit of the output voltages of the simulator and current sensor connected to the base of the regulating transistor, the regulating transistor is connected to the 'output terminals the simulator through a blocking diode and the input pins of the push-pull DC / DC converter, the output of which is connected to the input pins, and the specified simulator can be made inverse mi

In addition, an additional current-stabilized conversion cell can be entered in the simulator, the input of which is connected to the input terminals and the output directly to the output terminals of the simulator.

FIG. 1 shows a circuit diagram of a solar panel simulator, * in FIG. 2 is a graph explaining the principle of operation of the simulator. 25

The simulator of the solar battery, connected to the source of the supply voltage 1, contains a number of converter cells - current stabilizers 2 | - 2 ^, controlled keys 3 ^ ~ 3 ^ -4) »P ^az_z

divider diodes 4., -4 ^. ^, switch 5> containing a number of comparators.

5-1 "control transistor 6,

blocking diode 7, reversible push-pull converter of DC ₃₅ voltage 8, which includes 9 ^ and 9 ^ power transistors, shunted by reverse diodes 10 ^ and 10.2., input capacitor 11, transformer 12, rectifier diodes 13 ^ and 13g., 40

auxiliary transistors 14 ^ and 1h ^^ the comparison circuit 15 and the current sensor 16. The output of the simulator is connected to the load 17. The conversion cells 2 ₄ are connected to the source 1 at the input.

On the output of the cell, they are connected to the load via dividing diodes and shunted with controlled keys 3-, “3 (g4-1), and cell ⁵⁰ Ν is connected to the load directly, Controlled keys 3 ^ -3 (ν-ι) ^{πο into} * ° controller coupled to respective outputs of comparators 5 ^ -5 (Ν-Ό 'some inputs ⁵⁵ which podklyug cheny to the reference voltage source, and the other - to the output current sensor 16. The control transistor 6 is connected

parallel to the output of the simulator through the diode 7 and the input pins of the reversible push-pull converter 8, shunted by capacitor 11. Power transistors 9 ^ and 92 ^and reverse diodes 10 ^ and 102> are connected to the primary half-windings of the transformer 12 of the converter and rectifier diodes 13ί and 13 ₂ respectively and transistors 14 ^ and 14 ^. The output pins of the converter 8 are connected to the source 1. The output of the comparison circuit 15 is connected to the base of the regulating transistor 6, and the inputs respectively to the output of the simulator and the output of the current sensor 16.

The simulator proceeds as follows.

All converter cells of 2 ^ - 2 _M provide at their outputs a flow of stabilized direct current Ts. In idle mode of the simulator, the voltage from the sensor input 16 is maximum and exceeds

reference voltage and _op g and _op (^ -1) of all comparators of switch 5 (figure 2). In this case, at the outputs of all the comparators, the voltage is positive, and the controlled keys 3- | ^- З (ц_-,} are closed. This ensures a short circuit of cells 2 ^ - and their complete shutdown

from the load circuit 17 separating diodes - 4 (m_, 0.

In this mode, the current is supplied to the common circuit only from one cell 2 and flows completely through the control transistor 6. The voltage to

the output of the current sensor TB linearly decreases as the load current increases, and the same voltage is the reference for the linear voltage regulator represented by the transistor .6 and the comparison circuit 15- Since the voltage is maximum at 1 c = 0, the voltage at the 11 c load is also maximum , since the specified stabilizer in any case seeks to ensure the condition and _d £ c, ₆ .

With increasing current 1c, current transistor 6 and voltage

C ^ and and _n decrease. At 1 c = voltage 1) ^ it will reach level 11 _ogi , as a result of which the comparator 5 ^ will overturn, and the key 3-1 will open. The currents 1 ₅ and T _& (figure 1) will abruptly increase, and the voltage 1C, as before, will be completely determined by the load current. A further increase in 1c will lead to

915186

a subsequent decrease in and and _n .

At 1 _n r2 1 <, the new cell 2 ₂ and so on will connect to work.

An increase of 1 c occurs up to the value 1 _And =, with 5

where all cells are connected to the load, and the current is 1 ^ = 0. Further reduction of load resistance 17 can not lead to an increase in 1N "of only accompanied by decrease of the output voltage ¹⁰ zheniem 11ts.

When the load current decreases by? The reverse process is observed, when the “extra” cells are transferred from the energy transfer mode to the load to the short circuit mode.

To improve efficiency and reduce the simulator operating voltage and the power dissipation across the control transistor 6 in its collector circuit 20 is entered reversible push-pull DC converter 8. The current 1 ₆ alternately passes through transistors 92 and September _4, wherein the power 1 _{to 6} and returns to IP - 25 point 1. Voltage and β at the input of the converter 8 is determined by the value u ^ ~ ', where <Ц / «/ £ the transformer ratio of the transformer 12 *, U - the voltage on the source 1. 30

By choosing the parameters and in such a way that ΙΙβ and _nopt , it is possible to significantly reduce the voltage on the transistor 6 and to return the corresponding part of the power to the source 1. 35

Since transistor 6 in general can have a pulsating current (when 1 ^ ~ is high) or a current varying due to 40 1c change, the input terminals of the converter are shunted by capacitor 11, which improves the operation of the converter. In order that during a short circuit in the load circuit the discharge current 45 of the capacitor 11 does not flow in the inverse direction of the transistor 6, the blocking diode 7 is connected in series with the latter.

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When the simulator is in short-circuit mode, the voltage on the capacitor 11 - and _in can be reduced to zero due to the no-load current of the converter. And this will cause an increase in voltage and power dissipation on the transistor 6 in the first moments after an abrupt increase (when the load current is reset).

To exclude such a phenomenon, the converter 8 is reversible (the presence of transistors 14, 1Л ₂ and diodes ΙΟ4, 11p. In this circuit, the voltage υθ at the input of the converter is always equal to the value of C ,. ъ and _iopG, and therefore the power at transistor 6 * cannot exceed ι & (υ _Η χχ-υ _Ηοπ τ λ ·

When the simulator operates in the mode of maximum power output (TSn * and _H opt ~, the voltage across the transistor is almost zero, and therefore the efficiency of the simulator is especially high.

To simplify the circuit, one of the cells (2 # ') is connected to the load directly, which makes it possible to exclude one isolating diode and one comparator from the device in comparison with the known circuit.

Thus, the proposed device in comparison with the known is characterized by a high efficiency, which makes it more preferable for use.

Claims (3)

Claim 1. Simulator of DC source with high internal resistance, containing a number of current-stabilized converter cells, the input of each of which is connected to the input terminals of the simulator (intended for connecting the power supply, and the output is shunted by a controlled key and connected to the output terminals of the simulator through separation diode, a switch whose outputs are connected to the input of controlled keys, and the input is connected to the output of the load current sensor of the simulator, and a regulating transistor, the base of which This is connected to the output of the simulator's output voltage and load current comparison circuit, characterized in that, in order to increase efficiency, the control transistor is connected to the output pins of the simulator via a blocking diode and input pins of the input push-pull DC / DC converter, the output of which is connected to the input pins of the simulator. '915186 7 2. The simulator is π.1, which is based on the fact that the specified two-: clock converter is made reversible. 3. The simulator according to claim 1, that is, that the additional current-stabilized converter cell, the input of which is connected to the input terminals, is introduced, and eight output - directly to the output pins of the simulator.