SU1398023A1 - Rectifier protection device - Google Patents

Abstract

The invention relates to power converter technology and can be used in process automation systems. The purpose of the invention is to improve noise immunity. By introducing a binary decoder 18, a BILY-NOT element 19, and an element 58 OR 20 connected through duration selectors 21, 22, the influence of switching dips and impulse noise is eliminated, 3 sludge. (L

Description

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The invention relates to electrical engineering, namely to power converter technology, and can be applied in power supplies of process control systems.

The purpose of the invention is to improve the noise immunity of the device to protect the rectifier.

FIG. 1 shows a functional diagram of the device; in fig. 2 - timing diagrams (a) and code table (b), explaining the operation of the device; in fig. 3 - functional block diagrams.

The device contains power valves t-6, to which sensors 7-12 of conductivity are connected and block 13 to 25

thirty

35

loads, automatic switch valve power bridge. The presence connects the device to the network via terminals 15-17, full decoder 18, element 6Ш1И-НЕ 19, element 58 OR 20, selectors 21 and 22 of the pulse duration are connected to the inputs of the automatic switch 14.

Sensors 7-12 contain (fig. 3a) coupling capacitor 23, isolation transformer 24 with windings 2.5-27, carrier frequency signal generator 28, low-power rectifier 29, filter capacitor 30 and threshold element 31.

The circuit breaker has two windings 32 and 33 (Fig. 3b), which perform the function OR.

The device works as follows.

When all the valves 1-6 are in good condition, only two of the six valves can be in the open state.

Synchronously with the transition of one or another valve to the conductive state at the output of the conductivity sensors 7-12, signals of Yag are formed. 1, and their number is two.

Consider a rectifier as a source for generating a 6-bit binary code. In this case, we assign diode 1 the value Q of the lower bit, valve 6, the value Qg of the higher bit. The size of the remaining bridge gates corresponds to their composition in FIG. one.

40

45

50

the redundant code point in any of the bits causes the zeroing of all the inputs of element 19 (Fig. 1) and the appearance of the Log. G at one of the outputs of element 20. As a result, elements 19 and 20 go to the state of one output, and the signal Log. About a certain time delay appears at the output of the selectors 21 and 22. In this case, the automatic switch 14 shuts off the faulty power valve 1-6 of the rectifier from the network.

Elements 19, 22 and 20, 21 are mutually duplicating in order to increase the reliability of the diagnostic process, the violation of which can occur due to faults directly in the paths of the rectifier protection circuit. For example, element 19 may turn out to be in a faulty zero output state, in this case elements 20 and 21 perform their protective functions. If element 20 does not function, the rectifier network will be disconnected by elements 19 and 22. Similarly, disconnection and if any of the elements 21 and 22 or the windings 32 and 33 (fig. Zb) of the circuit breaker fails. The failure of any element of the decoder 18 also leads to the switch-off of the rectifier, since in any case the elements of the decoder orye

In this case, the signals are decoded at the inputs either at the inputs

A binary code combination (Fig. 25) for each time interval is sequentially generated, which for a position code gives the sequence of numbers 6,18,24,9,33 and 36. This combination is uniquely related to the fact that the power circuit elements are in good condition rectifier and summed (with negation) using element 19. The output signal of the last

corresponds to the log. O, if the rectifier is operating in accordance with its specified algorithm. At the same time, the signals at the other outputs of the decoder 18 are equal to the Log.O that

determines the zero level of the output coordinate of element 20.

Suppose that at some time interval (Fig. 2b) the third has passed to the open and faulty state

 gate power bridge. Availability

the redundant code point in any of the bits leads to zeroing of all the inputs of element 19 (Fig. 1) and the appearance of the Log. G at one of the outputs of the element 20. As a result, elements 19 and 20 go into a single output state, and the signal Log. About a certain time delay appears at the output of the selectors 21 and 22. In this case, the circuit breaker 14 shuts off the faulty power valve 1-6 of the rectifier from the network.

Elements 19, 22 and 20, 21 are mutually duplicating in order to increase the reliability of the diagnostic process, the violation of which can occur due to faults, directly in the paths of the rectifier protection circuit. For example, element 19 may turn out to be in a faulty zero-out state, in which case elements 20 and 21 perform their protective functions. If element 20 does not function, the rectifier will be disconnected from the network at the expense of elements 19 and 22. Similarly, disconnection occurs when malfunctions of any of the elements 21 and 22 or the windings 32 and 33 (Fig. 3B) of the automatic switch 14. The failure of any element of the decoder 18 also leads to disconnection by straps. bodies, as with any variant of the correct elements of the decoder, which

form signals either at the inputs

element 19, or at the inputs of element 20. Tyme way, the proposed option of protecting the rectifier is completely

It meets the requirements of self-control, when a fault in the diagnostic paths should lead to the disconnection of the power part of the circuit or be compensated for by a redundant efficient diagnostic path.

The selectors 21 and 22 prevent the triggered operation of the circuit breaker 14, since they do not allow the Q faults of the rectifier, to its command inputs, signals whose durability is not uniquely associated with the failure of any of the gates 1-6 of the bridge, and is a consequence of the natural variation of the parameters of the elements of the sensors 7-12 (Fig. For).

Generator 2 & forms a high-short circuit. This is a sharp decrease in the amplitude of the input to the element 31, is set to

The use of the device n to improve the reliability of the bodies, to increase the reliability of protection, the reliability of the

Claims (1)

Formula t5 The total (20–100 kHz) square wave signal with an average zero value. In the case of the non-conducting state of the diode G, the resistance of its transition is sufficiently large, and the transformer 24 on the side of the winding 25 operates in idle mode. The resistance of the capacitor 23 for the frequency of the generator 28 is negligible, but great for the frequency of the mains voltage. Thereby, the influence of the power network of the rectifier on the operation of the conductivity sensor is eliminated. When valve 1 is closed, the amplitude of the signal at the output of rectifier 29 is maximum and exceeds the threshold level of element 31. In this case, the output sensor of the conductivity sensor is equal to Log. ABOUT. When diode 1 opens, capacitor 23 bypasses winding 25 and transformer 24 goes into mode 20 25 A device for protection in an up to a three-phase scheme, at the input of which for automatic: switch switches with com- mand inputs, containing valve status sensors which are designed. Parallel to the corresponding rectifier, two pulse selectors, the outputs of which are intended to be connected to the following inputs of the automatic switch, What is different, in order to increase the protection level of a straightener, but with a full six-digit d 30 rum, element 6ILI-NOT and e 58IL, the outputs corresponding to the worker from the rectifier diodes, connecting the BLI-NO element, the output is connected to the input of the first pulse duration, the distance of the controller is connected to the element 58 OR, you; with the entrance of the second selek  heat pulses. 35 faults rectifier, short circuit This entails a sharp decrease in the amplitude of the signal at the input of element 31, which is set to state Log.1. The use of the device will allow to increase the reliability of the operation of the rectifier, to increase the reliability of the operation of the protection, the accuracy of determination faults rectifier, I Formula of gain faults rectifier, I A device for protection of a rectifier made up to a three-phase bridge circuit with an automatic installed at its input: a switch with two command inputs containing six valve state sensors whose inputs are intended to be connected in parallel with the corresponding rectifier diode, two pulse selectors, and outputs which are intended to be connected to the corresponding inputs of the circuit breaker, characterized in that, in order to increase the noise immunity of the protection of the rectifier, it is provided full six-bit decoder, element 6ILI-NOT and element 58IL, the decoder outputs corresponding to the operating state of the rectifier diodes are connected to the inputs of the BILE-NE element, the output of which is connected to the input of the first pulse width selector, the remaining outputs of the dehair controller are connected to the inputs of element 58IL, you; | SOD of which is connected to the input of the second selector of the pulse width. d 1398023