SU1473032A1 - Device for controlling semiconductor devices of static converter - Google Patents

Abstract

The invention relates to a converter technique and can be used to control semiconductor devices of a static converter. The aim of the invention is to improve the noise immunity and efficiency of the device. An additional diode 17 prevents current from flowing through the resistor 15 in the direction opposite to the flow of the generated pulse through the circuit: common point of the shoulders of the phase-shifting bridge, diode 13, resistor 15, capacitor 7, diode 9, capacitor 6, diode 8, middle point of the secondary winding of the transformer 1 Similarly, diode 16 prevents the flow of a counter current in the resistor 14 of the second key circuit at the time when the voltage at the midpoint of the secondary winding of the transformer 1 changes sign from minus to plus. The device possesses higher efficiency and noise immunity, especially at sharp voltage surges and at current values less than the thyristor unlocking current. 2 Il.

Description

The invention relates to a converter technique and can be used to control semiconductor devices of a static converter.

The purpose of the invention is to increase the noise immunity and efficiency of the device.

Figure 1 shows the electrical diagram of a device for controlling semiconductor devices of a static converter; figure 2 - graphs explaining his work.

The device (Fig. 1) contains an input transformer 1, a variable resistor 2 and a capacitor 3 forming a phase-shifting bridge, two key circuits consisting of thyristors 4 and 5 with storage capacitors 6 and 7 and included in the diagonal of the phase-shifting bridge through diodes 8-11 .

Separating diodes 12 and 13 are connected so that the anode of each of them is connected to the control electrode of the thyristor of one of the key circuits, and the cathode is connected to the anode of the same thyristor. The positive plates of the storage capacitors 6 and 7 through the resistors 14 and 15, included in the conductive direction of the additional diodes 16 and 17, are connected to the anodes of the thyristors 4 and 5.

The device operates as follows.

In the half-period, when a plus voltage on the diagonal of the phase-shifting bridge is applied to the midpoint of the secondary winding of the transformer 1, and minus to the common point of connecting the arm elements of the phase-shifting bridge, the capacitor 7 is charged through the circuit: the middle point of the secondary winding of the transformer 1, the control electrode is the cathode thyristor 5, diode 10, capacitor 7, diode 11, the common point of the elements included in the shoulders of the phase-shifting bridge. When the current reaches the opening value of the thyristor 5, most of the charging current of the storage capacitor 7 flows through the circuit: the middle point of the secondary winding of the transformer 1, diode; 12, the anode-cathode transition of the thyristor 5, diode 10, ’capacitor 7, diode 11, the common point of the elements included • in the shoulders of the phase-shifting bridge (Fig. 2a, b).

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The voltage on the capacitor 7 increases according to a sinusoidal law to the amplitude value of the voltage on the diagonal of the phase-shifting bridge (Fig. 2c), the diodes 10 and 11 do not allow the capacitor 7 to be discharged with a subsequent decrease in voltage on the diagonal of the phase-shifting bridge for a period of 90-180 ° el. hail.

At the time when the transformer 1 point of voltage changes sign by minus, and at the common point of the phase-shifting bridge - from minus yes plus, the charge current of the capacitor 6 appears (Fig. Ze *), which flows along the circuit: common point of the elements of phase-shifting bridge, the transition control electrode - the cathode of thyristor 4, diode 9, capacitor 6, diode 8, the middle point of the secondary winding of the transformer 1. After turning on the thyristor 4, most of the charging current of the capacitor 6 flows through the diode and the anode - cathode transition of the thyristor 4 (Fig.2a ¹ , b '), and the capacitor 7 beg the positive lining of the capacitor 7, the resistor 15, the diode 17, the anode transition of the cathode of the thyristor 4, the negative lining of the capacitor 7 detects discharging along the circuit.

'Due to the fact that the turn-on time of the thyristor is relatively short, a pulse with a round front is formed on the load resistor 15 (Fig.2d). An additional diode 17 prevents the current from flowing through the load resistor 15 in the direction opposite to the flow of the generated pulse along the circuit: the common point of the shoulders of the phase-shifting bridge, diode 13, load resistor 15, capacitor 7, diode 9, capacitor 6, diode 8, the middle point of the secondary winding transformer 1. Similarly, an additional diode 16 prevents the oncoming current from flowing in the load resistor of the second key circuit at a time corresponding to 360 electric degrees, when at the midpoint of transformer 1 the applied voltage was changes sign from minus to plus. Thus, the device allows you to get two pulses over a period, shifted relative to each other by 180 ° (fig.2d, d ').

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By shifting the voltage of the diagonal of the phase-shifting bridge relative to the voltage of the network, they carry out a shift of the generated pulses. $

The device has a higher efficiency and higher noise immunity, especially when there are sharp surges in the mains voltage, when the surge in the oncoming current through the load is at its maximum, and when the current is less than the thyristor is unlocked when most of the current flows through the load in the opposite direction, how additionally installed diodes prevent the oncoming current from flowing through the load resistors.

Claims (1)

Claim A device for controlling semiconductor devices of a static converter, containing a phase-shifting bridge, first and second thyristors, the cathode of each of which is connected through the first and second isolation diodes to the positive lining of the first and second capacitors, respectively, and one terminal of the first and second load resistors, respectively. negative plates of the first and second capacitors are connected to the cathodes of the second and first thyristors, respectively, and the anodes of the third and fourth respectively, of the separation diodes, the cathodes of which are connected to the control electrodes of the second and first thyristors, respectively, the control electrodes of the thyristors are connected to their anodes through the fifth and sixth separation diodes and connected to the diagonal of the phase-shifting bridge, characterized in that, in order to increase the noise immunity and efficiency of the device other water You are a ^one of the first and second load resistors are connected to the anodes of the first and second thyristors, respectively, via first and second additional isolation diodes.