SU781786A1 - Pulse-shape current stabilizer - Google Patents

Description

(54) PULSE CURRENT STABILIZER

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The invention relates to electrical engineering and can be used in power supply devices of automation equipment, battery charging devices, measuring equipment,

 Known current regulators pulsed form l.

The closest of the known technical solutions is a current regulator of a pulse form, a current rectifier on thyristors, the input circuit of which is connected to the terminals for connecting the supply voltage, a current sensor inserted into the output circuit of the indicated rectifier, a comparator, one input of which is connected with the source of the reference voltage, and the output with the input of the phase-shifting unit, the output connected to the control input of the current rectifier on thyristors 2.

The comparison of the controlled parameter in the specified stabilizer is made each half period, and the output voltage must be well smoothed, which requires the use of a bulky filter in the output circuit. In addition, in the scheme of the known device it is difficult to ensure the ter r - h ::; 1Л :; , :: RSH |

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the accuracy of stabilization, because when applied to a current stabilizer it is impossible to provide a high voltage level on a capacitor,

 necessary for normal operation of the diode-transistor switch and comparator. As a result, a low level signal acts at the input of the comparator, commensurate with the drift of the comparator bias voltage. In addition, the presence of the power filter significantly impairs the dynamic characteristics of the device. °

The purpose of the invention is to increase

S precision current stabilization and improved dynamic performance.

The goal is achieved by the fact that in a current regulator of a pulsed form, containing a current rectifier

20 on thyristors, the input circuit of which is connected to the terminals for connecting the supply voltage, a current sensor included in the output circuit of the indicated rectifier, comparator, one input

25 of which is connected to the source of the reference voltage, and the output to the input of the phase-shifting unit, the output connected to the control input of the rectifier current on the thyristors, is introduced

30 amplifier, one input through which

the resistor is connected to a current sensor, two connected between the inverting input of the amplifier and its output are parallel circuits, one of which is made of the primary winding of the isolation transformer and the capacitor connected in series and the other. an isolation transformer includes a series-connected diode and a second capacitor, the latter being connected to the second input of the comparator.

The drawing shows a circuit diagram in principle.

The current stabilizer includes a current rectifier 1 on the thyristors, a load 2, a current sensor 3, a resistor 4, an amplifier 5, a thyristor b, an integrating capacitor 7, a separation transformer 8, a diode 9, a second capacitor 10, a comparator 11, a photoelectric shifter 12 and forming: tel 13 pulses.

The device works as follows.

The signal from current sensor 3 is fed to amplifier 5 through the input resistor 4. Amplifier 5 integrates a current pulse passing through load 2 during a half-period of the supply network. At the end of the half cycle, the key b receives a pulse from the generator 13, the integrating capacitor 7 is discharged through the primary winding of an isolation transformer 8, which has a large transformation ratio. Since the secondary winding of the separation transformer: torus 8 is loaded on a series-connected diode 9 and a second capacitor 10, the current arising in it provides a charge for the capacitor 10. At the same time, it is easy to provide any. ngGpr level of the wife on the capacitor 10, for example, the choice of the value of its capacity. The voltage on the capacitor 10 is compared with the reference voltage on the device 11, the output of which, after passing through the phase shifter, the device 12 determines the instant of switching on the thyristors of the rectifier 1 in the next half-period.

The proposed device has improved dynamic characteristics (increased speed.) Due to the absence of a power filter in the device. This is especially important when applying the proposed device in systems with reduced requirements for output current pulsations (for example, charging devices, power supplies, electric drives and

and the like), since it allows to exclude cumbersome power filters.

An increase in the accuracy of current stabilization is achieved in the proposed device by reducing to zero the bias voltage of the amplifier in each half-period of the network, by closing the input and output circuits of the amplifier 5 with a switch b.

An additional advantage of the proposed device is the possibility of its operation at low signal levels from the current sensor. This allows the use of low-power current sensors, such as conventional shunts used in electrical measuring instruments.

Due to the fact that the proposed device periodically corrects the drift of the bias voltage, the requirements for the amplifier in this parameter are small and it is possible to use simple integrated operational amplifiers,

Claims (2)

1. Author's certificate of the USSR 462259, cl. H 02 M 7/10, 1973. 2. Authors certificate of the USSR 538463, cl. H 02 M 7/10, 1979.