SU754558A1 - Method of protecting thyristorized converter - Google Patents

Description

The invention relates to the field of power semiconductor technology of direct current electric trains.

A known method of protection of the thyristor converter, in which they control the end of the switching of the thyristors, form a pulse, and if the shutdown time of the valves is less than the set value, a signal is sent to the protection executive [ΐ].

The disadvantage of this method is the impossibility of detecting modes of blocking and all-round traction motor.

There is also known a method of protecting a thyristor converter supplying a traction motor containing a main, commuting and perezaryadny thyristors, in which

control the magnitude and sign of the rate of change in the output current and, at a certain value, act on the control pulses of the converter thyristors (2).

The disadvantage of this protection method is the impossibility of protecting the converter in regenerative braking at high speeds.

driving speeds

2

reliability during regenerative braking over the entire range of speeds by separating the amplitude modulation and pulse-width modulation modes, serves control pulses to the switching thyristor with a time delay relative to the control signals of the rechargeable thyristor depending on the parameters of the output current,

FIG. 1 given the basic scheme of implementation; in fig. 2 is a diagram explaining the method of protection.

15 A device that implements the method

protection, contains a thyristor pulse converter 1, connected between the armature of the traction motor 2 and the excitation winding 3, which are shunted by diodes 4 and 5, respectively. Consistently with the anchor of the traction motor 2, the armature current sensor 6 is connected via the motor mode contact 7 to the positive pole of the power supply 8. Parallel to the shunt diode 4 the brake contactor 9 is connected. Between the common point of the motor contactor 7 and the armature current sensor 6 and the anode of the shunt diode 5

3

754558

four

brake contactor 10 on.

The thyristor pulse converter includes a main thyristor 11, reverse-coupled diode 12, a switching circuit of capacitor 13 and reactor 14, a rechargeable thyristor 15, a reverse-shunted circuit from a series-connected diode 16 and a thyristor 17, the anode of which is connected to its control electrode through a pulsed zener diode 18.

A current zero sensor 19 is connected in series with the recharge thyristor 15, and its output is connected to a controlled delay line 20. The output of the delay line is connected to the control electrode of the switching thyristor 21, the anode of which is connected to the current zero sensor 19, and the cathode to current zero sensor 22 The output of which is connected to the controlled delay line 23. The output of the delay line 23 is connected to the control electrode of the main thyristor 11 "The output of the armature current sensor is connected to the comparison elements of the delay lines 20 and 23. The control electrode recharge the thyristor 15 is connected to the control unit 24.

Between the common point of the zero current sensor 19 and the anode of the switching thyristor 21 and the negative pole of the power source 8, the charging resistor 25 is turned on,

The transition from the thrust mode to the brake mode is carried out after the run-up when reversing the excitation winding of the traction motors. In the zone of high speeds braking is carried out with the independent initiation of traction motors. In the initial period of deceleration, the excitation is carried out from the power source through a briefly closed contactor 7, and then through diode 4. In this case, the converter operates in an amplitude modulation mode implemented by the thyristor 21. The control signals to the thyristor 21 come from the delay line 20 connected between the current zero sensor 19 and the control electrode of the thyristor 21.

The control of the magnitude and sign of the rate of change of the output current is carried out by the armature current sensor 6 and the control unit 24. Regulation

amplitude modulation is carried out by changing the delay time of line 20 depending on the output voltage of the armature current sensor.

The amplitude modulation mode is implemented in the output voltage range of the armature current sensor and _about 4 and _O t «ί ίνπαι .. This is illustrated by the diagram. 11 "TD * (Fig. 2), where the armature current values are plotted along the abscissa, and the ordinate axis is the voltage values at the output of the armature current sensor.

By reducing the speed and achieving a current sensor output voltage value of the armature and the delay time _of the line 20 becomes zero, and the system automatically enters the latitudinal regulirova'niya mode self-excited traction motor. This mode takes place in the output voltage range of the armature current sensor 20 I) ρηίη 1 and 4 0 _о · Control of this

mode is carried out using the delay line 2 3, the comparison element which begins to work at the output voltage of the armature current sensor and _o .

Claims (1)

Claim • er A method of protecting a thyristor converter feeding a traction electric motor containing a main, commuting and recharging thyristors, at which the magnitude and sign of the rate of change of the output The current and, at a certain value, affect the transistor thyristor control pulses, characterized in that in order to increase reliability during recurrent braking over the entire speed range by separating the amplitude modulation and pulse width control modes, control pulses are applied to the switching thyristor with time delay in relation to the pulses of control of the charge-exchange thyristor depending on the parameters of the output current.