SU1695461A1 - Converter - Google Patents

Description

one

(21) 4467883/07

(22) 08/01/88

(46) 30,11.91.Byul. №44

(72) A.P. Shershunov, G.N. Gul Kovich, A.D. Dushin and I. S. Golovitsyn

(53) 621.314.57 (088.8)

(56) USSR Copyright Certificate No. 1182610, class, H 02 M 3/335, 1983. USSR Copyright Certificate

Mg 982163, cl. H 02 M 3/335, 1980. (54) THE CONVERTER

(57) The invention relates to a converter technique and can be used in a power supply of electronic equipment. The purpose of the invention is to increase

reliability by providing cyclically restorable overload protection. In the converter containing inverter 1 with an output transistor, rectifying diodes 2 and 3. Output filter 10, an additional transformer 4, an inductive element 8 and an actuating unit 9 are inserted, forming an inductive energy metering device. The device effectively implements cyclically restored protection against overloads and short circuits at the output, current surge is limited when power is supplied, the presence of an energy meter allows the converter to be used as a charging device. 3 il.

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

The purpose of the invention is to increase reliability by providing cyclically reducing overload protection.

FIG. 1 shows the converter circuit; in fig. 2 - time diagrams of voltages and currents of converter elements; FIG. 3 is an example of a specific circuit implementation.

The converter contains a push-pull inverter 1 with an output transformer, rectifying diodes 2 and 3, an additional transformer 4 with primary windings 5 and 6 and a secondary winding 7, an inductive element 8, an auxiliary device 9 and an output filter 10.

FIG. 3, the executive node 9 contains a threshold element 11, a one-shot transistor 12-15, a resistor 16 and a capacitor 17 and a diode bridge 18, and the inverter 1 contains a rectifier with a filter 19, a diode bridge 20, a control transformer 21 and a master oscillator 22. Besides In addition, the secondary side of the converter is equipped with damping capacitors 23 and 24.

The converter works as follows (Fig. 3).

In the absence of a short circuit load on the output circuit, the actuator 9 and its one-shot are powered by an independent voltage supply from the rectifier with filter 19 of the master oscillator 22 and are in a steady state. In this state, transistors 12 and 13 are open, and transistors 14 and 15 are closed. In this case, the excitation voltage from the output winding of the master oscillator 22 through the diode bridge 20, the open one-vibration transistor 12 is fed to the input winding of the control transformer 21 of the inverter 1.

Inverter 1 forms an alternating voltage at its output, which in opposite phase with respect to the zero output of the output transformer secondary winding goes to the rectifying diodes 2 and 3, alternately charging capacitors 23 and 24, which are dampers for the power transistors of the inverter 1. Current la inductive element 8, starting from zero, will increase in time. In proportion to it on the primary half windings 5 and 6 of transformer 4, the amplitude of the variable component will increase, which will be heme larger, the greater the value of the current through the inductive element 8, which is transformed by the output winding 7.

Thus, on the winding 7 get

galvanically isolated from the power circuit of the converter input, the voltage of the control signal U is proportional to the magnitude of the current la, and hence the load current of the converter. At time ti (Fig. 2)

the voltage, reaching the selected threshold value determined by the threshold element 11, triggers the actuator 9 and, as a result, relieves the alternating voltage on its

time out

t t2-t1,

where ti is the time of energy storage in the inductive metering device;

v.2 - the time when the current energy metering

Is becomes zero when the metering energy is transferred to the load or dissipated in the elements of the output circuit of the converter in the presence of a short circuit.

Consider in more detail the work of the actuating device 9 in this embodiment. At time ti, the voltage U. having exceeded the threshold value of the voltage of the threshold element 11, transistor 15 opens for a short time, transferring the one-shot from a stable state to a temporarily stable state. In this state, transistors 12, 13 and 15 are closed. Since the transistor switch 12 is closed at the same time, the excitation voltage is released

the voltage at the time t t2-ti, which is numerically equal to or greater than the time of the temporarily stable single-oscillator state, is determined from the PA input and at the output of the inverter 1 and is determined by the values of the resistor 16 and capacitor capacitance 17. After the time of the temporarily stable state or others after recharging capacitor 17 capacitors 17, transistors 12 and 13 open, and transistor 14 closes (transistor 15 closes immediately after removing voltages Ui and U), the one-shot actuator 9 returns to its original state stable state and further cycles will be

0 to repeat as long as a short circuit or overload occurs.

Thus, the device effectively implements cyclically restoring protection against overloads and short circuits at the output, and also limits the inrush current when the power is applied to the converter. The presence of an inductive energy meter allows the converter to be used as a charging device.

Claims (1)

Claims of the Invention A converter comprising a push-pull inverter with an output transformer, the output winding pins of which are connected to rectifying diodes, and an output filter connected to the output pins, characterized in that, in order to increase reliability by providing cyclically restored overload protection, additional transformer, inductive 0 the element and the actuator, forming an inductive energy metering device, the beginning and end of the first and second primary windings of the additional transformer are connected to the cathodes of the corresponding rectifying diodes, and the other terminals are combined and through the inductive element are connected to one of the output terminals, and the secondary winding of the additional transformer is connected to the input of the executive node, the output connected to the control input of the inverter. WV