SU1040582A1 - Direct current electric drive - Google Patents

Abstract

A DC ELECTRIC DRIVE, containing two main electric motors, a power source to which two parallel circuits from a series-connected first core and first thyristor, second thyristor and second core, third thyristor connected between the core, reverse diodes connected parallel to the core, as well as a switching capacitor, characterized in that, in order to improve the weight and size characteristics by reducing the capacitance of the switching capacitor, Werth thyristor connected in series with the third, two additional thyristors connected in series between the brushes had polar. korea, charge thyristor and resistor, the switching capacitor being connected between the common point of the additional thyristors and the common point of the third and fourth thyristors, to which the charging one is also connected, (L thyristor connected via a resistor to the positive pole of the power source.

Description

The invention relates to electrical electronics and can be used in dc electric propulsion systems with two main propeller motors. A DC electric drive is known with selective switches included in the main current circuits and made in the form of a controller. The electric drive contains a cam controller, the main contacts of which are included in the core circuit of the generator and electric motors. In addition to the main contacts, the switches have auxiliary contacts included in the exciter circuit of the generator as well as in the control, blocking and signaling circuits. Switching the main contacts, designed for the flow of large currents, provide all the required operating modes of the actuator. However, the known device has poor dynamic characteristics. In addition, the main contacts of the selector switches are not intended to break the arc under voltage, so. as it requires the use of complex and cumbersome switching devices with arc suppression. Therefore, all switching in the main circuit is possible only if there is no current flowing through it. For this purpose, the excitation of the generators is removed at the switching time of the controller, which increases the switching time, thereby deteriorating the dynamics. The closest in technical essence to the present invention is a direct current electric drive comprising a two-core propeller electric motor, a power source to which two parallel circuits from the series-connected first core and first thyristor and second core are connected via a starting unit return diodes connected in parallel to the core, as well as switching capacitor 2. A disadvantage of the known device is the considerable size of switching capacitor. Because the capacitance er is selected from the current switching condition of two motors connected in parallel, whereby are increased dimensions and weight of the apparatus as a whole. The purpose of the invention is to improve the weight and size characteristics by reducing the capacity of the switching capacitor. The goal is achieved by the fact that the DC motor contains two main electric motors, power source, to which two parallel circuits from the series-connected first core and first thyristor, second thyristor and second core, the third thyristor connected between the cores, reverse diodes, connected in parallel to the core, as well as the switching capacitor, a fourth thyristor, connected in series with the third, is introduced, two additional thyristors connected in series atelno between brushes had polar anchors, a charging thyristor and a resistor, the switching capacitor is connected between the common point additional thyristors and the common point of the third and fourth thyristors to which is also connected for p projectile loader thyristor is connected via a resistor to the positive pole of the power source. Figure 1 presents the scheme of the proposed device; 2, diagrams showing his work. The direct current drive contains a power source 1 to which two parallel circuits are connected through the starting unit 2 from the first auxiliary box 3 and the first thyristor 4, the second thyristor 5 and the second box 6, and the third thyristor 7 connected between core 3 and 6, reverse diodes E and E connected in parallel to the core 3 and 6, as well as switching capacitor 10. The device has a fourth thyristor 11 connected in series with the third thyristor 7, two additional thyristors 12 and 13 connected in series between times Korya's pole brushes, charge thyristor 1 and resistor 15. Switching capacitor 10 is connected between the common point of additional thyristors 12 and 13 and the common point of the third 7 and fourth 11 1 thyristors, which is also connected to charge thyristor 1 connected through a resistor 15 positive (m source-1 supply pole.

The device works as follows.

When the thyristors 7 and 11 are turned on, the cores 3 and 6 are connected in series, as a result of which the voltage on each crust is equal to half the source voltage and the electric motor rotates at a speed approximately equal to half of the maximum value.

When adjusting the rotational speed in the range of 0.5 ,, c. And above, the maximum speed corresponding to the case when the voltage on each crust is equal to the voltage of the power source), the device operates according to the following algorithm. I At the time in: belt .2), the first 4 (Uunpx) and the second .5 (U (jnn5) thyristors, additional thyristor 13 (icpr) b) and charge thyristor 1 (U.f, p 14) are turned on. In this case, the cores 3 and 6 are connected in parallel, the voltage on each core (U / j and U) becomes G equal to the voltage of the power source and the capacitor 10 is charged through the resistor 15 to the source voltage with a plus sign on the top facing (). Charger consisting of thyristor H and re-. Sistor 15, is intended for the initial charge of the switching capacitor 10 and does not participate in the operation. Then, at time t / 2, an additional thyristor 12 (Ugtip) and a third thyristor 7 (Uvjnp) are simultaneously turned on - as a result, a reverse voltage is applied to the second thyristor 5, which turns it off, and the switching capacitor 10 recharges from before the source 1 power plus sign on the bottom plate. Second measles 6 disconnects from power source 1.

At time t), the fourth thyristor 11 is turned off (an additional thyristor 13 forms a blocking voltage of the switching capacitor 10 on the first thyristor. The thyristor k is turned off and the power supply source 1 is removed from the first core 3- Then, at times t and tg, the thyristors turn on 5 and i and core 6 and 3 are connected to a power source.

Further, the above-described electrical processes periodically repeat t /, t and tg, and so on, as a result of which the voltage on the cores 3 and 6 represents a periodic sequence of pulses. The magnitude of the medium voltage and, accordingly, the rotational speed of the electric motor can be smoothly changed using a thyristor control system (not shown) due to a change in the ratio of time intervals for core 3

-t9-ts

ib-i4

for cor 6.

in the maximum rotational speed mode, the thyristors 4 and 5 are switched on permanently and the cores 3 and 6, connected in parallel, are connected to the power source 1.

The starting block 2 is intended to limit the inrush current during start-up when the series-connected boxes 3 and 6 are connected to a power source.

Due to the fact that the switching capacitor periodically switches the current of a single core, and not two, as in the known device, its capacity is two times less, which improves the weight and size characteristics of the proposed electric drive.

Claims (1)

A DC electric drive containing a two-arm electric motor ', reverse diodes connected in parallel with the armature, as well as a switching capacitor, characterized in that, in order to improve the overall dimensions by reducing the capacity of the switching? capacitor, a fourth thyristor is inserted into it, connected in series with the third, two additional thyristors connected in series between the opposite-pole armature brushes, a charging thyristor and a resistor, and a switching capacitor. connected between the common point of the additional thyristors and the common point of the third and fourth thyristors, g to which a charging thyristor is also connected, connected through a resistor to the positive pole of the power source. SLU 1040582 1040582 2