SU1406732A1 - Contactless switching device - Google Patents

Abstract

The invention relates to a pulse technique and can be used in a power semiconductor converter circuit. The purpose of the invention is to simplify the device, increasing its efficiency and reliability. The contactless switching device contains a power controlled switch 1, to the second output terminal of which three circuits are connected in parallel. Circuit elements are connected in series: the first contains an inductive load 4 and the primary winding 6 of a magnetic reactor (MP) 5. The second is diode 9 and the first secondary winding MP 5, and the third is capacitor 10 and diode 11. Between the middle point of the third circuit and the first output key 1 connected - connected in series the second secondary winding 8 MP 5 and the third diode 12. 1 Il. (L

Description

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The invention relates to a pulse technique and can be used in power semiconductor converter technology.

The aim of the invention is to simplify the device, increase efficiency and reliability.

The drawing shows a circuit diagram of the proposed device.

The contactless switching device contains a power controlled switch 1, two buses 2, 3 of the power supply, an inductive load 4, a magnetic reactor 5 with a primary winding 6 and two secondary windings 7, 8, a reverse diode 9, a capacitor 10, and also a reverse one the second and third diodes 11 and 12.

The magnetic reactor 5 is made on a core with a non-linear magnetic characteristic. One of the output pins of the key 1 is connected to the power supply bus 2, and between the second output pin of the key 1 and the power supply bus 3 are connected in parallel three circuits, the first of which contains an inductive load 4 connected in series and the primary winding 6 of the magnetic reactor 5, the second the first diode 9 and the first secondary winding 7 of the reactor 5 are connected in series, and the third is the capacitor 10 connected in series and the second diode 11 is turned back on. In addition, between the middle point of the third circuit (exact a compound of the capacitor 10 and diode 11) and the first output terminal of the switch 1 is turned on tseESh of series-connected second secondary winding 8 of the reactor 5 and the back of the third diode 12 included.

The principle of operation of the device is as follows.

At the beginning of the operation cycle, immediately before unlocking the key 1, the capacitor 10 has a residual charge, the potential of the upper plate being negative, and the bottom potential positive. At the time of unlocking, the voltage on the power switch 1 decreases almost to zero. The load current 4, which is connected through diode 9, begins to flow through key 1. The potential of the second output pin of key 1 and the associated common point of three parallel circuits is lowered. In this case, a voltage surge is applied to the winding 7 of the reactor 5, and the core of the reactor 5 starts to reversal in a positive direction. The magnetomotive force (MDS) in it is set close to zero, as the core goes into an unsaturated mode of operation, in which it has a high magnetic permeability. Through the diode 9, in which the accumulated charge is stored, a current flows in the opposite direction, equal to the current of the winding 7, which in turn is connected with the current to

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load flowing through the primary winding 6 of the reactor 5, the ratio determined by the transformation ratio between these windings. Thus, the current of diode 9 is limited. The limited current flowing through the diode 9 in the opposite direction during its switching simultaneously means the limited current through the key 1 during the switching of the diode 9, which caused minor energy losses both in diode 9 and in key 1.

When current flows through the diode 9 in the reverse direction, the voltage of the winding 7 of the reactor 5 is transformed into the winding 8, which ensures the locked state of diode 12, while the capacitor 10 retains the residual charge. After locking the diode 9, the current of the winding 7 stops. Due to the inductive nature of the load 4, after the reverse resistance is restored and the diode 9 is blocked, 20 neither the direction nor the current magnitude of the winding 6 of the reactor 5 changes (it remains equal to the current 1 n load 4). The core of the magnetic reactor 5 is in a state of high magnetic permeability, and a current is generated in the winding 8 and the diode 12 is opened 25. The capacitor 10 is recharged along the circuit: diode 12 - winding 8 - capacitor 10 - key 1. First, the voltage on the winding 8 has a positive polarity at the beginning and a negative one at the end, while the core of the reactor 5 is re-magnetized in the positive direction, and after discharge of the capacitor 10, the voltage at the ends of the winding 8 changes polarity, which causes the magnetization reversal of the core of the magnetic reactor 5 in the negative direction. However, the core of the reactor 5 remains in a state of high magnetic permeability.

As the potential of the upper plate of the capacitor 10 rises up to the voltage of 40 pyranya diode 11, this potential is fixed at a level almost equal to the potential of the power supply bus 3, and the charge of the capacitor 10 ends. After in the process of magnetization reversal in

In the negative direction, the core of the reactor 5 goes into a state of negative saturation, the transformation of the current from the winding 6 to the winding 8 stops and the diodes 11, 12 are closed. The charge of the capacitor 10 occurs with a limited current, the size of which is determined by the load current and the transformation ratio between the windings 6 and 8 of the magnetic reactor 5. Since the charge current of the capacitor 10 flows through the switch 1, the switch current 1 turns out to be limited.

55 both at the stage of the reverse conduction of diode 9, and at the stage of charging of the capacitor 10, the current through key 1 is limited in absolute value, which accounts for insignificant energy losses in the output circuit of key I.

When locking key 1, when its current begins to decrease, diode 11 is opened, and capacitor 10 begins to discharge. In this case, the voltage on the key 1 increases smoothly from zero as the potential of the associated capacitor 10 plate increases. The smoothness of the increase in voltage on the key 1 from zero causes insignificant switching energy losses during its locking, as well as the reliability of the locking itself. After the capacitor 10 is completely discharged, diode 9 is unlocked and the current of inductive load 4 begins to be distributed between two parallel branches consisting of winding 7, diode 9 and capacitor 10 and diode 11. This causes a charge on the capacitor 10 and the voltage applied to the winding 7 increases, which causes the load current to be switched to diode 9 more quickly than in the prototype. Therefore, by the beginning of the new cycle, the bottom 11 is locked, which is guaranteed to prevent switching current surges through the key 1 when it is unlocked e which increases efficiency and reliability of the device.

In the new cycle of operation, the described processes are repeated.

The invention does not change if the inductive load 4 is made in the form of a series-connected windings of the throttle filter and a power-consuming load, in parallel with which the filter capacitor is connected.

Claims (1)

Invention Formula A contactless switching device containing a power controlled switch, to the first output terminal of which a power supply source is switched on, between the second output output and the second power supply bus, three circuits are connected in parallel, the first of which is in the form of series-connected inductive loads and the primary winding of a magnetic reactor having two 5 secondary windings and made on a core with a nonlinear magnetic characteristic, the second circuit - in the form of the first diode and the first secondary winding of the magnetic reactor connected in series, the third circuit in the form of serially connected. a capacitor and a second diode which is turned back on, to the combined terminals of which is connected by the first output a fourth circuit of the second secondary winding of the magnetic reactor and the rpeibero diode connected back in series, characterized in that, in order to simplify, increase the efficiency and reliability, the second fourth output circuits made of pseudo-connected secondary windings 0 of the magnetic reactor and the reverse of the included third diode is connected to the nepEvi; y output terminal of the power controlled key. 0 five