SU961033A1 - Solid-state converter protection apparatus - Google Patents

Description

(54) DEVICE FOR PROTECTION OF TRANSISTOR CONVERTER

one

The invention relates to electrical engineering, in particular, to protection devices for voltage transducers on transistors, and can be used to protect secondary power sources of electronic equipment.

Independent current protection devices are known in which a thyristor and a diode 1 are sequentially included in the power supply bar.

The disadvantage of these devices when they are used to protect transducers is their low efficiency due to the loss of power on these elements.

Protection devices for non-autonomous voltage converters are known to contain. current sensor included in the load circuit, comparison, amplification, actuator, and inverter control circuit.

The disadvantage of these devices is the difficulty in using to protect a converter with several output circuits.

The closest in technical essence to the present invention is a device for protecting a transistor converter with a push-pull start circuit connected to the power supply through a resistive voltage divider containing a comparison unit — a gain, whose input is connected to the current sensor of the converter, and the output is connected to the input of a switching voltage. the element connected between the power supply of the emitters of the transistors and the common point of the separators of the diodes connected between the bases of the transistors 2.

A disadvantage of the known device is its low reliability due to incomplete locking of the transistors of the converter in the event of a short circuit or overload.

The purpose of the invention is to increase reliability.

Claims (3)

The goal is achieved by the fact that a device for protecting a transistor converter with a push-pull starting circuit connected to a power source through a resistive voltage divider is provided with an additional diode and switching element connected between the other power bus and the midpoint of the resistive divider directly or through an additional diode, 39 moreover, the inputs of the switching elements are connected in series or in parallel with the output of the comparison-amplification unit. FIG. 1 shows the basic scheme of the device; in fig. 2 - a variant of the protection circuit of the converter on transistors of the opposite conductivity type. A device for protecting a transistor converter 1 with a push-pull start-up circuit 2 connected to power supply through a resistive voltage divider 3 contains a current sensor 4 connected to the input of the comparison-amplification unit 5, the output of which is connected to the input of the switching element 6 connected between the power supply of the emitters of the transistors 7 of the converter 1 and the common point of the separation diodes 8 connected between the bases of the transistors 7 and with the input of the additional switching element 9 connected between the others with this power supply and cf one point of the resistive divider 3 directly (Fig, 1) or through an additional diode 10 (Fig. 2). The device works as follows. During normal operation of converter 1, the voltage created by its current consumption on current sensor 4 is small, and there is no unlocking voltage at the inputs of switching elements 6 and 9. If there is a short circuit or overload in any of the output circuits of the voltage converter. from the current sensor 4, will exceed the threshold value, with this block 5 the comparison gain increases the impulse to unlock the associated switching element 6 and the additional switching element 9. Unlocking the switching elements leads to tionary locking the transistors 7 transform ers push-pull circuit 1 and run 2. As kommutiruyupshh elements mrgut be applied thyristors and transistors When applying thyristors converter "after actuation protection device remains in zOpertom state, when using transistors - automatically restores the operation mode after the overload is removed. In the circuit of the switching element it is possible to turn on an alarm lamp warning of an accident. Thus, the introduction of an additional switching element 9 makes it possible to lock the start-up circuit 2 and thereby increase the reliability of locking the transistors 7 of the converter 1 in the event of short circuits and overloads. The invention The device for protecting a transistor converter with a push-pull starting circuit connected to the power supply via a resistive voltage divider, containing a comparison-amplification unit, the input of which is connected to the converter's current sensor and the output connected to the input of the switching element connected between the emitter power bus transistors and a common point of separation diodes connected between the bases of the transistors, characterized in that, in order to increase reliability, it is equipped with an additional diode and ommutiruyuschim zlementy connected between another power schinoy and the midpoint of the resistive divider either directly or via an additional diode, wherein the inputs of the switching elements connected in series or in parallel with the output of the comparison unit - gain. Sources of information taken into account during the examination 1. USSR author's certificate No. 705593, cl. H 02 H 7/10, 1978. 2. USSR author's certificate number 653674, cl. H 02 H 7/10, 1977. 3. Technical documentation BG2.087.079. wvnnrww J. -0 -10; i ™ J "l lirti tzt -ftVi