SU564983A1 - Traction motors exciting current control device - Google Patents

Description

The device contains counter thyristors 1 and 2, an oscillatory inductive-capacitive circuit formed by a capacitor 3 and a choke 4, a relaxant control pulse generator 5, a charging resistor 6, a distor 7 and a rectifier 8. The device is connected to the excitation windings 9 and 10, t and electric motors 11 and 12. The field windings are connected in series with the windings of Korean electric motors. The device includes a current transformer 13, a resistor 14, a capacitor 15, an additional resistor 16, a matching transformer 17 and a load resistor 18.

The output of the relaxator generator 5 of control pulses is connected to the control electrode of the thyristor 1 connected in the direction of current flow of the traction electric motors. The active capacitive circuit is formed by a resistor 14 and a capacitor 15. The primary winding of the transformer 13 is connected in series with the active capacitive circuit 14 and 15, and the secondary winding is connected to the control electrode of the thyristor 2 connected against the direction of current flow of the traction motors.

The device works as follows.

In the initial state, the full current of the core flows through the excitation windings and the usual sequential excitation mode of the traction motors is maintained. As the current of the traction motors increases so that the voltage drop across the field windings becomes sufficient to trigger the generator 5, the thyristor 1 is turned on.

As follows from the diagrams of FIG. 2, at time i, the voltage / a on the thyristors and the voltage Up on the capacitor of the generator 5 becomes equal to the release voltage of the relaxer and the current pulse, Gu, appears at the output of the generator 5 This current pulse arrives at the thyristor control electrode 1. Turning on the thyristor 1 leads to shorting of the field windings. At the same time, a current IB flows through the thyristor 1, the value of which is determined by the current of the traction motors and the parameters of the oscillatory inductive-capacitive circuit 3 and 4. Due to the oscillatory circuit, the current IB in the thyristor circuit has a shape close to sinusoidal. In this form of current IB, at time t, the current becomes zero and the thyristor 1 is turned off.

When the thyristor 1 is turned on, a current pulse appears in the control electrode circuit of the thyristor 2. For this purpose, the control electrode circuit is connected via a current transformer 13 and an active-capacitive circuit containing a resistor 14 and a capacitor 15 to the thyristor 2 anode. the flow of the reverse half-wave of the oscillatory inductive-capacitive current circuit 3 and 4. In this case, the field windings remain short-circuited, and the current of the traction electric motors

flows through thyristor 2. At time / 3, current IB becomes zero again and thyristor 2 is turned off. At this point in time, the voltage t / a on the thyristors is restored and the current of the traction motors flows through the field windings.

At time i, the voltage f / p on the capacitor of the generator 5 increases again to a value equal to the release voltage of the relaxer, which ensures the formation of a current pulse iy and the switching on of the thyristor 1. At the same time, the electromagnetic processes are repeated.

Periodically short-circuiting, by thyristors 1 and 2, the excitation windings of the traction electric motors, ensures the reduction of the excitation current JB in a steady-state mode with respect to the current of the traction electric motors.

The average value of the input power of the described device in the steady state operation is equal to the power dissipated in its elements. The parameters of the oscillatory inductive-capacitive circuit 3 and 4 and the generator 5 are chosen in such a way that the voltage on the field windings is almost completely independent of the maximum voltage on the oscillatory inductive-capacitive circuit 3 and 4

and, therefore, from the current of traction electric motors. For example, a change in the load current of traction motors three times can lead to a change in voltage on the field windings only by 20%. Wherein

A decrease in current of electric motors causes a decrease in current in the field windings.

In the case of an abrupt change in the voltage of the power source, an abrupt change in the current in the circuit of the resistor 16 and the primary winding of the transformer 17 occurs. Pa is applied to the secondary winding of the transformer 17. d. s., which through the rectifier 8 is fed into the circuit of the load resistor 18 and the cathode of the dynistor 7, which causes the latter to turn on and shunt the charge circuit of the generator relaxer 5. The formation of the thyristor control current pulses 1 stops and a forced change in the current occurs

excitation due to the flow of the entire current of the core through the excitation windings. After the end of the transient process when the voltage of the power supply voltage changes abruptly, the dynistor 7 is turned off and the normal operation of generator 5 is restored. Since the signal, when a voltage jumps out of the voltage of the traction electric motors, is supplied to the dynistor 7 circuit. for any sign of change in the power supply of traction electric motors. The presence of a capacitor 3 in the oscillatory

The inductive-capacitive circuit causes a delay in the build-up of voltage on the field windings. However, the delay time is negligible and the presence of a capacitor 3 in the oscillatory circuit does not have a noticeable effect on the nature of the transients during voltage fluctuations of the power source.

The performance of the proposed device was tested experimentally on a prototype made in relation to the VL10 electric locomotive. The prototype is made on thyristors TL 200 8 class. To ensure operation at a current of 500 A, three thyristors are connected in parallel. The oscillatory inductive-capacitive circuit has a capacity of 400 µF and an inductance of 25 µG. As follows from the graphs of FIG. 3, a change in current in the common circuit from 200 to 700 A leads to an increase in the current B of the excitation winding circuit only from 200 to 205 A. Thus, the described device practically eliminates the dependence of the current in the excitation windings of the traction electric motors on the core current when they are switched on in series the core circuit allows independent excitation.

Technical and economic efficiency of the proposed device follows from the comparison with the system of independent excitation of the traction electric motors of the electric locomotive VL 10, made using a thyristor driver. The need to force a change in current in the excitation windings with such an excitation system causes an increase in the maximum power of the exciter to 500 kW at a nominal power consumed by the windings of the main poles, 63 kW.

The power of the proposed device has a maximum value with a slight weakening of the floor and for an electric locomotive VL10 is 36 kW. The mass and cost of the power equipment of the described device, respectively, are 9 and 3.15 times less than the mass and cost of the equipment of the thyristor driver.

The device can be used to provide independent excitation of direct current electric locomotives with a series-parallel connection of traction motors.

FIG. Figure 4 shows the circuit diagram of the system of independent excitation of the traction electric motors of a direct current electric locomotive with series-parallel connection of the windings of the core and shunting of the excitation windings by the described device. In this case, the described BIG device I and I are connected in parallel to the field windings 9, 10 and 9 Yu connected in series in the common circuit of the electric motors I, 12 and 111, 12i. The control pulse generators of these devices through the rectifiers 8, 8i, the transformer 17 and the resistor 16 are connected to a power source. In addition, they have a small negative current feedback for the traction motors for each branch separately via current sensors 19 and 20. The inclusion of the excitation windings 9, 10 and 9i, lOi in the common circuit of the traction motors allowed to create an excitation current, a greater current of the core, even with maximum field weakening.

Claims (3)

1. A device for regulating the excitation current of the traction electric motors, containing counter thyristors connected in parallel to the excitation windings and an active capacitive circuit, as well as a control pulses relaxator generator, the output of which is connected to the control electrode of one of the above thyristors connected in the direction of current flow traction motors, characterized in that, in order to improve the traction characteristics, it is provided with an oscillatory drive connected in parallel with the excitation windings a capacitive current circuit and a current transformer, the primary winding of which is connected in series with the active capacitive circuit and the secondary connected to the control electrode of another of the above thyristors connected against the direction of current flow of the traction motors, is connected to the control pulses A single resistor to the terminals of the field windings. 2. The device according to claim 1, characterized in that, in order to force the excitation current when the supply voltage oscillates, it is provided with a transformer connected to the supply voltage source, the secondary winding of which is connected to the relaxator input via the rectifier and dynistor control pulse generator. Sources of information taken into account in the examination 1.Patent of France No. 2151747, cl. H 02 R 7/00, 1973. 2. The patent of England No. 1061850, cl. H 2J, 1967. 3. USSR author's certificate number 415180, cl. In 60L 7/16, 1972. Us Ufl / I / L Wigg