SU1372565A1 - Electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control a traction motor. The aim of the invention is to reduce losses in the switching circuit and the power of the installation equipment. The device contains an additional diode 9 connected between the windings of the core 4 and excitation 5. The cathode of the additional thyristor 8 is connected to the cathode of the additional diode 9. In this device a current of the nominal current of the core flows through the switching node, which ensures a reduction in losses in the switching circuit. 1 il. (L from vj to SP Od cl

Description

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- o11372565

The invention relates to electrical engineering and can be used as a traction electric drive in electric rolling stock of the subway and land railways.

The purpose of the invention is to reduce energy losses in the switching circuit and the power of installed equipment.

The drawing shows a diagram of the drive.

The drive contains a series connected thyristor 1, shun10 connected to a power source.

the voltage is increased while simultaneously opening the thyristor 1 and the main thyristor 10 of the chopper 3 and delaying the opening of the auxiliary thyristor 1A. Opening, if necessary, an additional thyristor 8 within the period of recharging of the switching capacitor 12 leads to the feeding of the excitation winding 5.

The transition from the thrust mode to the electric braking mode occurs without switching in the power circuit. The interrupter 3, winding the core 4 and the main thyristor 10 of the interrupter 3 and the bumper 5 of the electric motor, the shunt-auxiliary thyristor 14 opened with the second 6 and break simultaneously, the thyristor 1 and 7 additional reverse diodes, and an additional thyristor 8 opens the thyristor 8 connected ano-20 simultaneously at the end of the switching period 30

house to the breaker 3, as well as an additional diode 9 connected between the common point of the winding 4 core, the second 6, third 7 reverse diodes and the excitation winding 5, while the cathode 25 of the additional thyristor 8 is connected to the common point of the cathode of the additional diode 9 and excitation winding 5 .

The interrupter 3 contains the main thyristor 10, shunted by a reverse diode 11 and a circuit of series-connected switching capacitor 12, droplets 13 and auxiliary thyristor 14, and also a diode 15.

The drive operates as follows.

In the motor mode, when the thyristor 1 is turned on, the switching capacitor 12 is charged to the voltage of the power source. After the auxiliary thyristor 14 is switched on, double recharging of the switching capacitor 12 occurs, resulting in the loss of part of the initial voltage. At the end of the recharge (commutation) period, the thyristor 1 opens, resulting in the dosing of the switching capacitor 12 through the winding 4 core and the excitation winding 5. This provides a mini50

maximum motor current. Approaching the opening time of the thyristor 1 by the time opening of the auxiliary thyristor 14 leads to an increase in the average value of the voltage applied to the motor. The coincidence of the opening times of the thyristors 1 and 14 ends the first stage of voltage regulation. Further

of This provides power to the excitation winding 5 from the power source. The recovery current flows along the circuit: winding 4 core, reverse diodes 11 and 2, power supply, reverse diode 7.

As the movement speed decreases, the moment of opening the thyristor 1 and the additional thyristor 8 approaches the moment of simultaneous opening of the main 10 and auxiliary 14 thyristors until the excitation winding 5 reaches the nominal value. In this case, the circuit and the circuit for closing the winding 4 core to the excitation winding are energized: winding 4 core, interrupter 3, additional thyristor 8, excitation winding 5, reverse diode 7. After the excitation winding reaches its nominal value, the turn-on delay time of the thyristor 1 ceases to decrease. The delay time of switching on the additional thyristor 8 continues to decrease to zero with respect to the moment of switching on the main 10 and auxiliary 14 thyristors, increasing the time of the short-circuited core circuit, i.e. the system goes into pulse recovery mode at nominal excitation. Next, the delay time of switching on the main thyristor 10 begins to increase.

The introduction of an additional diode 9 leads to the fact that the excitation current is made up of an independent feed current from the power source and the core current flowing in the range of 40

45

55

0

five

0

of This provides power to the excitation winding 5 from the power source. The recovery current flows along the circuit: winding 4 core, reverse diodes 11 and 2, power supply, reverse diode 7.

As the movement speed decreases, the moment of opening the thyristor 1 and the additional thyristor 8 approaches the moment of simultaneous opening of the main 10 and auxiliary 14 thyristors until the excitation winding 5 reaches the nominal value. When this is excited, the circuit for closing the winding 4 core to the excitation winding: winding 4 core, interrupter 3, additional thyristor 8, excitation winding 5, reverse diode 7. After the excitation winding reaches its nominal value, the delay time of switching on the thyristor 1 ceases to decrease. The delay time of switching on the additional thyristor 8 continues to decrease to zero with respect to the moment of switching on the main 10 and auxiliary 14 thyristors, increasing the time of the short-circuited core circuit, i.e. the system goes into pulse recovery mode at nominal excitation. Next, the delay time of switching on the main thyristor 10 begins to increase.

The introduction of an additional diode 9 leads to the fact that the excitation current is made up of an independent feed current from the power source and the core current flowing in the interval

five

five

closed loop state and does not exceed the nominal value. In general, the rated current of the core current flows through the switching node, which ensures a reduction in losses in the switching circuit and reduces its weight and dimensions.

Claims (1)

Claim of an Invention Electrode comprising a series-connected thyristor connected to a power source, shunted by a first reverse diode, an interrupter, a core winding and an excitation winding of an electric motor, shunted respectively by a second and third reverse diodes, and an additional thyristor connected by an anode to the chopper, characterized in that aim, to reduce energy losses in the switching circuit and the power of the installed equipment, an additional diode connected between bschey point of the armature winding, second, third freewheeling diodes and the excitation winding of the motor, wherein the cathode auxiliary thyristor-connected to the common point of the cathode of the diode and the additional excitation winding.