RU2268172C2 - Device for electric braking of electric train - Google Patents

Abstract

FIELD: electrical engineering; traction electric drive.

SUBSTANCE: proposed device contains supply source and two groups of dc traction motors. Windings of armatures and field windings of electric motors are connected into cross bridge circuit. Brake resistor is placed in bridge diagonally opposed pair of junctions. Moreover, diode, two contractors, thyristor generative resistor, two current relays, regenerative relay and matching unit are available. Beginning of armature windings of first group of electric motors is connected with beginning of field windings of second group of electric motors. End of armatures windings of first group of electric motors is connected with anode of diode. Cathode of diode is connected with plus terminal of supply source through series-connected first current relay, regenerative resistor and first contactor. First contactor is shunted by thyristor whose anode is connected with common terminal of regenerative resistor and first contactor and with first output terminal of matching unit. Second output terminal of matching unit is connected with control electrode of thyristor, and input, with regenerative relay output placed between minus and plus terminals of supply source, plus terminal of supply source being connected with thyristor cathode. Second current relay is connected between output of connection of beginning of armature windings of second group of electric motors and ends of field windings of second group of electric motors and minus terminal of supply source. First current relay is made for operation when regeneration current reaches its lower threshold value, and its making contact is placed in circuit of coil of first contactor. Second. Second relay is made for switching off regenerative braking mode when regeneration current reaches upper threshold value.

EFFECT: enlarged range of regenerative braking using regeneration.

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Description

The invention relates to the field of traction electric drive and can be applied on electric vehicles with DC motors powered from a DC voltage network.

A device is known that contains DC traction motors, a power source, a braking resistor connected between the connection points of the armature windings and the series-connected field windings of the first and second groups of traction motors, four diodes, a charging resistor (RU 6753, B 60 L 7/24, 1998 )

The disadvantage of this device is the insufficient speed range for the implementation of the electric braking mode using recovery and, as a result, the low efficiency of the device.

A device for electric braking of electric rolling stock is known, containing two groups of DC traction motors, a power source, a braking resistor connected between the connection points of the armature windings and the series connected excitation windings of the first and second groups of traction motors, three diodes, two contactors (RU 2077145, cl B 60 L 7/22, 1997 - prototype).

The disadvantage of the device adopted for the prototype is the insufficient speed range for the implementation of the electric braking mode using recovery and, as a result, the low efficiency of the device.

The objective of the invention is to create a device that provides an extension of the range of speeds of electric braking with the implementation of the recovery mode, increasing efficiency and saving electricity.

The technical result is achieved by the fact that in the device for electric braking of electric rolling stock containing a power source, two groups of DC traction motors connected by a cross bridge circuit, a braking resistor is included in the diagonal of the bridge formed by armature windings and excitation windings of DC traction motors, wherein the beginning of the windings of the anchors of the first group of traction DC motors is connected to the beginning of the excitation windings of the second group of traction of DC motors, a diode, two contactors, a thyristor, a recovery resistor, two current relays, a recovery relay and a matching unit, the end of the armature windings of the first group of DC traction motors is connected to the anode of the diode, the cathode of which is connected through the first connected in series current relay, recovery resistor, first contactor with a positive terminal of the power supply, the first contactor is shunted by a thyristor, the anode of which is connected to the common output of the recovery resistor and about the contactor, and with the output of the matching unit, the second output of which is connected to the thyristor control electrode, and the input - with the output of the recovery relay connected between the thyristor cathode and the negative terminal of the power supply, to the general output of the connection of the beginning of the armature windings of the second group of DC traction motors and of the end of the field windings of the second group of DC traction motors, a second current relay is connected, the other output of which is connected through a second contactor to the negative terminal of the power source.

Due to the fact that new elements have been introduced into the device and new connections have appeared, the range of electric braking speeds using recovery is expanding.

The drawing shows a circuit diagram of the proposed device.

In accordance with the drawing and according to the claims, a device for electric braking of electric rolling stock containing a power source 1, two groups of DC traction motors connected by a cross bridge circuit into a diagonal of a bridge formed by armature windings 2, 3, 4, 5 and field windings 6, 7, 8, 9 of the DC traction motors, the brake resistor 10 is turned on, while the beginning of the windings of the anchors 2, 3 of the first group of DC traction motors is connected to the beginning of the windings in excitation 8, 9 of the second group of traction DC motors, the end of the windings of the anchors 2, 3 of the first group of traction DC motors is connected to the anode of the diode 11, the cathode of which is connected through series-connected the first current relay 12, the recovery resistor 13, the first contactor 14 with a positive terminal power supply 1, the first contactor 14 is shunted by the thyristor 15, the anode of which is connected to the common output of the recovery resistor 13 and the first contactor 14, and with the output of the matching unit 16 (for example, relay contact and resistor), W a swarm output of which is connected to the control electrode of the thyristor 15, and the input - with the output of the regeneration relay 17 connected between the cathode of the thyristor 15 and the negative terminal of the power supply 1, to the common output of the connection of the beginning of the windings of the armature 4, 5 of the second group of DC traction motors and the end of the windings excitation 8, 9 of the second group of DC traction electric motors is connected to the second current relay 18, the other output of which is connected through the second contactor 19 to the negative terminal of the power source 1.

The device operates as follows. In braking mode, traction motors are connected in a cross-bridge circuit. A brake resistor 10 is included in the diagonal of the bridge formed by the armature windings and field windings. The total current of the armature windings of both groups of traction motors flows through it. The current of the armature windings 2, 3 of the traction motors of the first group flows through the field windings 8, 9 of the traction motors of the second group, and the current of the armature windings 4, 5 of the traction motors of the second group flows in the circuit loop containing the field windings 6, 7 of the traction motors of the first group. Cross connection of the windings of traction motors in the electric braking mode ensures the electrical stability of the circuit.

To implement the regenerative braking mode, the contactor 19 and the thyristor 15 are turned on, when the recovery current reaches the threshold value, the relay 12 is activated and closes its contacts in the coil circuit of the contactor 14, the contactor turns on and shunts the thyristor 15. The recovery current flows through the contactor 14, and the thyristor 15 closes. When the recuperation current decreases to a threshold value, the relay 12 turns off the contactor 14 and the thyristor 15 is turned on. If there is no voltage in the power supply, the control electrode of the thyristor 15 does not receive control signals, since the relay 17 goes into an unexcited state and opens its lock in the thyristor control circuit 15. When the recovery current increases to the threshold value, the relay 18 is activated and turns off the regenerative braking mode.

The regeneration resistor Rp 13 is needed to match the voltage generated by the traction motors in braking mode and the power source. At Rp = 0, the recovery current will be determined by the resistance of the braking resistor Rt and the potential conditions at the anode and cathode of diode 11; at Rp = Rt, the recovery current decreases by half, the resistance value Rp affects the value of the recovery current to a greater extent than the voltage of the power source; at Rp≪Rt, the recovery current depends on the voltage of the power source; at Rp = ∞, the recovery current is zero.

When the recovery mode is turned off, the device operates in the mode of rheostatic braking.

Thus, the proposed device provides the maintenance of a given braking current in traction engines when the voltage in the power source and the speed changes, and accordingly the change in the recovery current in a wide range (from the lower to the upper threshold of current relays), and increase the efficiency.

Claims (1)

A device for electric braking of electric rolling stock containing a power source, two groups of DC traction motors, the armature windings and excitation windings of which are connected by a cross-bridge circuit, while the beginning of the armature windings of the first group of traction electric motors is connected to the beginning of the excitation windings of the second group of traction electric motors, brake a resistor included in the diagonal of the formed bridge, a diode and two contactors, characterized in that a thyristor is additionally introduced into it p, a recovery resistor, two current relays, a recovery relay and a matching unit, while the end of the armature windings of the first group of traction electric motors is connected to the diode anode, the cathode of which is connected through the first current relay, the recovery resistor and the first contactor to the positive terminal of the power supply, the first contactor is shunted by the thyristor, the anode of which is connected to the common output of the recovery resistor and the first contactor, as well as to the first output terminal of the matching unit, the second output terminal of which is connected n with a thyristor control electrode, and the input with the output of the recovery relay connected between the minus and plus terminals of the power source, the last of which is connected to the cathode of the thyristor, between the terminal connection of the beginning of the armature windings of the second group of traction electric motors with the ends of the field windings of the second group of traction motors the minus terminal of the power source is connected to the second current relay, the first current relay is configured to operate when the recovery current reaches a lower threshold value, and e a normally open contact included in the coil circuit of the first contactor, the second over current relay configured to deactivate the regenerative braking with regenerative current increases to an upper threshold.