SU1367113A1 - Protected stabilized d.c.voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be applied in devices of secondary power sources, their protection and control. The aim of the invention is to increase reliability and enhancement of functionality. When the inverter fails, or when the supply voltage is suddenly and permanently lost, the voltage pulses on the secondary windings 6 and 24 of the power transformer 5 disappear. Fig. 11. At the first input 14 of the protection unit, a voltage of 15 is set to a logic zero. Due to the presence at the other input 20 of the voltage source of the reference voltage 23, the protection unit under voltage 15 is activated. 1 il. -09 I (f С о: а ч its Emergency si g / g

Description

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The invention relates to electrical engineering and can be applied in devices of secondary power sources, their protection and control.

The aim of the invention is to increase reliability and enhance functionality.

The drawing shows a diagram of a stabilized converter voltage with protection.

The converter contains a pulse-width modulator 1, an output connected to the control input of a power amplifier 2, intended to be connected by an input to a power source 3, and an output connected to the primary winding 4 of a transformer 5, the secondary winding 6 of which is connected via rectifier 7 to the terminal 8, the output pins of which 9 and 10 are connected to the voltage divider 11 and serve as the output of the converter. The output of the voltage divider 11 is connected to one input 12 of the amplifier 13 of the error signal and one input 14 of the voltage protection unit 15, one output 16 of which is connected to one input 1 7 of a pulse-width modulator, the other input 1Y - it is connected to the output of the error signal amplifier 13, another input 19 of which is connected to another input 20 of unit 15 for voltage, one input 21 of comparator 22 and output of source 23 of reference voltage. An additional secondary winding 24 of the transformer 5 is connected via an amplitude detector 25 to another input 26 of the comparator 22, the output 27 of which is connected to the output of voltage divider 11. The other output 28 of the voltage protection unit is intended for connection to control and signal circuits.

The stabilized voltage converter operates as follows.

During normal operation, the converter to the other input 18 of the pulse-width modulator 1 is fed an amplified error signal, which is a certain constant voltage value. This voltage is produced by the error amplifier 13, to the inputs of which a voltage is applied that is proportional to the difference in the output voltages of the converter and the source 23

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support stress. Depending on the value of the amplified error signal, the pulse width modulator 1 generates control pulses of a certain duration for controlling the power amplifier 2.

The voltage pulses on the secondary winding 6 of the power transformer 5 present during the operation of the converter are rectified by the superstructure 7, smoothed by the filter 8, as a result of which a constant voltage is applied to the output pins 9 and 10. Under the influence of perturbing factors (change in input voltage, change in load current) and the resulting increase (decrease) in output voltage, the difference in the values of voltages at the inputs of the error signal amplifier 13 increases (decreases). This in turn leads to a decrease (increase) in the duration of the control pulses generated by the pulse-width modulator 1, which is what stabilizes the output voltage.

. With an increase (decrease) in the output voltage of the setpoint set when the voltage protection unit 15 is configured and determined by a specific load, a negative voltage appears at one output 16 of the voltage protection unit 15 at one input 17 pulse-width modulator 1. When this. pulse-width modulator 1 stops the formation of control pulses, which leads to the locking of power amplifier 2. At the same time, an alarm appears on the other output 28 of the over-current protection unit, which can be used to switch off the stabilized converter or to activate the alarm, as well as to generate a special control signal. In this case, a converter malfunction signal is given, the Avarion indication is turned on, and the converter is disconnected from the supply voltage.

When the converter is turned on, one input 21 of the comparator 22 receives a voltage from the source 23 of the reference voltage. At the other input 26 of the comparator 22 (at the first moment of the converter start-up) the voltage is zero, since there is no

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voltage pulses on the windings of the transformer 5. At the same time, the comparator 22 by its output shunts the output of the voltage divider 11.

At the time of transient start-ups in the converter itself (at the time when the supply voltage reaches the pulse-width modulator 1 and the amplifier 13 of the error signal of its established values), the comparator 22 by its output 27 shunts the output of the voltage divider 1I. As soon as the supply voltage reaches the pulse-width modulator 1 and the error signal amplifier 13 of its established values, the pulse-width modulator 1 begins to generate control pulses. In this case, voltage pulses appear on the secondary windings 6 and 24 of the power transformer 5. The appearing voltage at the output of the amplitude detector 25 is fed to another input 26 of the comparator 22. At the same time, the comparator 22 stops shunting the output of the voltage divider 11. One input 12 of the amplifier 13 of the error signal and one input 14 of the protection unit starts to receive a voltage, the value of which is proportional to the value of the voltage from the output of the converter.

In the case of simultaneous launch of the N system of parallel operating DC / DC converters to a constant for a common load line, each of the converters is connected to the described switching process. At the same time, independent converters are started by disconnecting the corresponding inputs of the error amplifier and voltage protection device from the output of the voltage divider in each of the converters during the transient process.

This eliminates false C14 protection at the moment the system N is started up in parallel with the transducers.

When the converter operating in system N of parallel-connected converters fails, voltage pulses on the secondary windings of the power transformer disappear. The voltage at the output of the amplitude detector 25 becomes zero, while the comparator 22 with its

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the output shunts the output of the feedback divider 11. At one input 14 of the protection unit 15, the voltage is set to the voltage, the level of which corresponds to a logical zero. This leads to its triggering.

The alarm occurring at the other output 28 of the voltage protection unit 15 can be used as a trip signal, an alarm trigger signal, and a special forward signal.

In this case, information on the occurrence of a converter malfunction is supplied to the power supply system, the Avariya indication is turned on, and the converter is disconnected from the supply voltage, which allows the defective converter to be quickly retrieved from the N system of parallel operating voltage converters.

When a stabilized DC converter fails, or when a supply voltage is suddenly and permanently lost, voltage pulses hit the secondary windings 6 and 24 of the power transformer 5. The output voltage of the amplitude detector 25 becomes zero, and the comparator 22 with its output shunts the output of the feedback divider 11.

On the first input 14 of the protection unit 15, the voltage is set to a logical zero. Due to the presence on the other of the second voltage of the source 23 of the reference voltage, the voltage protection unit is activated.

The occurrence of an alarm signal corresponds to the moment when the voltage pulses disappear on the secondary winding of the power transformer 5, i.e. an alarm occurs earlier than the output voltage of the converter reaches the threshold of protection at the minimum level of the output voltage. This allows for increased security.

Claims (1)

Invention Formula Stabilized DC / DC converter with protection containing a pulse-width pulse 513 tor, output connected to the control input of a power amplifier, input intended to be connected to a power source, and output connected via a transformer to a rectifier whose output is connected to the input of a filter whose output terminals are connected to a voltage divider and used as the converter output, the voltage protection unit, the input connected to the output of the voltage divider, and the control output to the protective input of the pulse width modulator, the error amplifier, one course connected to the source opor136 voltage, the other input to the output of the voltage divider, and the output to the control input of the pulse-width modulator, characterized in that, in order to increase reliability and expand functionality, it is equipped with a comparator and an amplitude detector, and the transformer is provided with an additional secondary winding, the comparator output is connected to the output of a voltage divider, one input of the comparator is connected to the output of the reference voltage source, and the other input through an amplitude detector to an additional secondary th winding of the transformer.