JPH0223041Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The invention relates to a DC motor control device for an electric vehicle.
In particular, the present invention relates to a DC motor control device suitable for protecting a DC motor having separately excited field windings from flash.

[Background of the idea]

Figure 1 is a block diagram of a conventional DC motor control system for an electric car, and shows the case of two electric cars. It belongs to car number. In Fig. 1, 1 is an overhead contact line, 2 is a pantograph, 3 is an armature part of a DC compound motor (hereinafter referred to as the main motor), 4 is its series field winding, and 5 is the other one. The excitation field winding is connected so that the direction of magnetic flux is harmonious with the series field winding 4 during power running. 6 is a high-speed disconnector whose contacts automatically open to protect the armature portion 3 when excessive current flows through the armature circuit; 7
8 is a chopper device for controlling the separately excited field current of the separately excited field winding 5, and 9 is a cutter for the separately excited field circuit of the traction motor, and 9 is a chopper device for controlling the separately excited field current in the separately excited field winding 5. A flywheel diode for circulating current, 10 is ground.

Next, the operation when two electric cars are running coupled together will be explained. However, since the operation of the chopper device 8 is well known, the explanation will be omitted. When the separately excited field current flowing through the separately excited field winding 5 is reduced, the induced voltage in the armature portion 3 decreases, and the armature current flows from the contact line 1 to the ground 10, resulting in power running control. . Conversely, if the separately excited field current is increased to make the induced voltage in the armature section 3 higher than the voltage on the contact line 1, the armature current will increase to the ground 10.
It flows out toward the overhead contact line 1 and exhibits a regenerative braking action. In this way, power running and regenerative braking can be performed simply by increasing or decreasing the separately excited field current, and this is a feature of an electric vehicle control device using a DC compound-wound motor.

However, DC compound-wound motors have one major drawback compared to DC series-wound motors. That is 1
If the traction motor of a machine flashes out for some reason, there is a possibility that other traction motors connected in parallel with it may also flash out. In Figure 1, if A
Assume that an accident occurs in which a flash fault occurs at the grounding point 11 on the positive side of the main motor armature portion 3A of the No. 1 car. In this case, current flows from the overhead contact line 1 to the flash ground point 11, but in addition to this, current also flows from the main motor armature portion 3B of the healthy No. B car to the flash fault ground point 11. The reason for this is that because the separately excited field current flowing through the separately excited field winding 5B does not immediately decrease, the induced voltage in the armature portion 3B does not attenuate in response to the voltage drop in the contact line 1, and this induced This is because a current flows from the armature portion 3B to the flash fault grounding point 11 due to the voltage. Therefore, if only one main motor is flash-grounded, the remaining healthy main motors will also be flash-faulted. In this case, the high-speed shield breakers 6A and 6B open to provide protection, but protection is impossible because the closing time is long compared to the rise time of the rush current.

On the other hand, in the case of a DC series motor, there is no separately excited field winding 5 in Figure 1, so when an inrush current flows from a healthy main motor toward the flash fault grounding point, the field magnetic flux decreases and the electric motor Since the induced voltage in the child is reduced, inrush current is suppressed and a major accident does not occur. On the other hand, in a DC compound motor, the series field winding 4B is connected to the ground 10
Even if a current flows from B toward the pantograph 2B, the magnetic flux changes slowly because the separately excited field winding 5B is short-circuited by the flywheel diode 9B, and the inductance of the armature circuit is small, so the current does not flow. is hardly suppressed. Therefore, it may be considered that the current in this case is suppressed only by the inductance of the armature portion 3B and the grounding resistance of the grounding point 11.

FIG. 2 is a detailed view of the armature section 3 of FIG. 1, and to simplify the explanation, a two-pole DC motor is shown. The armature part 3 has two terminals 12,
13, an armature 14, two brushes 15 and 16, and a commutating pole 17.

By the way, in electric cars, conventionally the terminal 12
is connected to the overhead contact line side, and the terminal 13 is connected to the ground side. This is based on the general idea that windings with low voltage drop should be connected to the ground side to keep the potential to ground low.

In order to suppress the above-mentioned fault current, a method is sometimes adopted in which a reactor is added to increase the inductance of the armature circuit, but this is expensive, and also increases the weight and reduces the weight. This is extremely disadvantageous for an electric vehicle control device that uses field chopper control, which is characterized by low cost.

[Purpose of invention]

The present invention has been developed in view of the above, and its purpose is to provide a DC motor control device for electric vehicles that can prevent the spread of flashover damage to the main motor without adding any special equipment. be.

[Summary of the idea]

The present invention provides an electric vehicle equipped with a plurality of DC motors each having a commutating pole and a brush and having at least separately excited field windings, and a control device for controlling the current flowing through the separately excited field windings of the DC motors. In this case, the armatures of the plurality of DC motors are connected in series, and the DC motor that is closest to the positive power supply side has its commutative pole connected to the positive power supply side rather than the brush, and the armature of the DC motor that is closest to the positive power supply side is connected to the negative power supply side. For the DC motor that is closest to the side, the commutative pole is connected to the negative power supply side rather than the brush, and each contact of the reversor that switches between forward and reverse travel is connected to the DC motor that is closest to the positive power supply side when moving forward. The commutative pole of the DC motor closest to the negative power supply side becomes the negative power supply side, and when traveling in reverse, the commutative pole of the DC motor closest to the negative power supply side becomes the positive power supply side. This is characterized in that the commutating pole of the DC motor closest to the positive power source side is connected to the negative power source side.

[Example of idea]

The present invention will be explained in detail below using the embodiment shown in FIG.

FIG. 3 is a main circuit wiring diagram showing one embodiment of the DC motor control device for an electric vehicle according to the present invention, and shows the case of one vehicle. The same parts as in FIGS. 1 and 2 are as follows.
The same reference numerals are used except for those of A and B, and the description thereof will be omitted here. In FIG. 3, two DC compound motors each having a series field winding are connected in series to a power supply, and the series field winding 4 of FIGS. 1 and 2 is separately excited. A main motor consisting of a field winding 5, terminals 12, 13, an armature 14, two brushes 15, 16, and a commutating pole 17 is used as a first motor. 29, 30,
The armatures 14 and 28 are connected in series with the overhead contact line 1 using a main motor composed of a commutating pole 31, a series field winding 32, and a separately excited field winding 33 as a second motor. ing. However, armature 14,
28, the commutative poles 17 and 31 are connected in the illustrated relationship. In addition, 18 to 21 are the contacts of the reversing device that switches between forward and reverse, 18 and 19 are the forward side contacts of the reversing device, which close when moving forward, and 20 and 21 are the reverse side contacts of the reversing device, which are closed when moving backward. close.

Therefore, when moving forward, the armature 14 of the first electric motor is closer to the contact line 1 than the armature 28 of the second electric motor, and when moving backward, it is the opposite.
In either case, the commutating pole of the motor that is on the contact line 1 side is on the contact line 1 side. Therefore, when two cars, car A and car B, are connected, when the main motor of car A flashes to the ground point 11 (see Figure 1) on the positive side, the current flows to the closed ground point 11. The current is limited by the ground resistance of the ground point 11 as well as the inductance of the commutating pole 17 (in the case of forward movement) of the main motor of car A. In other words, the current flowing from car B to the grounding point 11 via the contact wire 1
This will be suppressed by an inductance of 7. Increasing the inductance of the current flowing from car B to the grounding point 11 is as follows:
It has a great effect in limiting the current of car B,
This prevents the spread of flash damage to other healthy traction motors connected in parallel to the power supply when a flash fault occurs in one traction motor, without the need to add any special equipment. can do.

Note that the series field windings 4, 32 are connected to the armature 14,
28 is connected to the negative power supply side, that is, to the ground 10 side.The reason is that the series field windings 4, 3
2 are connected to the contact line 1 side of the brushes 16 and 29, and if either of the two main motors flashes for some reason, the current flowing to the flashground point 11 will be further restricted, but the direct winding Field winding 4, 32
is overexcited by the short-circuit fault current, and on the other hand, the armature short-circuit current flows through the armatures 14 and 28, so
This is because a powerful brake torque is generated in the armatures 14 and 28, and the armatures 14 and 28 stop rotating.

In addition, contacts 18 to 21 of the reversing device for switching forward and reverse are installed, but even in this case, as shown in the figure, the commutative pole of the traction motor closest to the contact line 1 side is connected to the contact line 1. If it is set to the 1 side, the effect remains unchanged because the commutating pole remains connected to the contact line 1 side regardless of whether the main motor is switched between forward and reverse directions.

In the above explanation, the main motor is a DC compound-wound motor, but in the present invention, it may be a DC separately-excited motor that does not have a series-wound field winding and only has a separately-excited field winding. The same effect can be obtained.

[Effect of idea]

As explained above, the present invention has the remarkable effect of being able to prevent the spread of flash-fault damage to the main motor without adding any special equipment.

[Brief explanation of the drawing]

Fig. 1 is a main circuit diagram of the DC motor control device for an electric car, Fig. 2 is a detailed wiring diagram of the main motor armature part of Fig. 1, and Fig. 3 is an example of the DC motor control device for an electric car according to the present invention. FIG. 2 is a main circuit diagram showing an embodiment. 1... Tram line, 3, 3'... Main motor armature part, 4... Series field winding, 5... Separately excited field winding,
8...Chopper device, 9...Flywheel diode, 10...Grounding, 12, 13, 26, 27
...terminal, 14,28...armature, 15,16,
29, 30... Brush, 17, 31... Complementary electrode, 18
~21...Contact.

Claims (1)

[Scope of utility model registration request] An electric vehicle comprising a plurality of DC motors each having a commutating pole and a brush and at least a separately excited field winding, and a control device for controlling a current flowing through the separately excited field winding of the DC motor. The armatures of the two DC motors are connected in series, and the DC motor closest to the positive power supply side has its commutative pole connected to the positive power supply side rather than the brush, and the DC motor is closest to the negative power supply side than the brush. In the DC motor, the commutative pole is connected to the negative power supply side rather than the brush, and each contact of the reversing device that switches between forward and reverse travel is such that when moving forward, the commutative pole of the DC motor closest to the positive power supply side is connected to the negative power supply side. The commutative pole of the DC motor that is on the positive power supply side and closest to the negative power supply side becomes the negative power supply side, and when traveling in reverse, the commutative pole of the DC motor that is closest to the negative power supply side becomes the positive power supply side, and the A DC motor control device for an electric vehicle, characterized in that the commutating pole of the DC motor closest to the positive power supply side is connected to the negative power supply side.