JPH03145901A - Controller for electric rolling stock - Google Patents

Abstract

PURPOSE:To protect field winding without requiring any temperature sensor by stopping the operation of a field chopper when the temperature of the field winding, detected based on the conduction ratio, reaches a predetermined level. CONSTITUTION:Power is fed from a stringing 1 through a current collector 2 to a reactor 4 and a capacitor 5, where AC component is removed, thence fed to an armature winding 6 and a field winding 9. Armature current is controlled by means of an armature chopper control circuit 13 through an armature chopper 7, whereas field current is controlled by means of a field chopper control circuit 14 through a field chopper 10. Resistance of the field winding 9 is calculated based on the conduction ratio gammaF of the field chopper 10, field current and field voltage, and then the temperature of the field winding 9 is calculated based on thus calculated resistance. When thus calculated temperature reaches a predetermined level, operation of the field chopper 10 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an electric vehicle control device having a function of detecting an abnormal temperature rise in a field winding such as a DC shunt motor and stopping the main circuit. It is something.

[Conventional technology 1 The configuration of a conventional example will be explained with reference to FIG.

FIG. 2 is a circuit diagram showing a conventional electric vehicle control device.

In Fig. 2, the conventional electric vehicle control device has a contact line (1
), a current collector (2) in sliding contact with the current collector (2), a main circuit closing circuit breaker (3) connected to this current collector (2), and a filter reactor connected to this main circuit closing circuit breaker (3). (4), a filter capacitor (5) with one end connected to the filter reactor (4) and the other end grounded, and an armature winding (6) of a DC shunt motor connected to the filter reactor (4). , an armature chopper (7) whose one end is connected to the armature winding (6) and the other end is grounded, and the armature winding (6).
The armature chopper freewheel diode (8) connected in parallel to the filter reactor (4), the field winding (9) of the DC shunt motor connected to the filter reactor (4), and the field winding (9) ), the other end of which is grounded, a freewheel diode for the field chopper (11) connected in parallel to the field winding (9), and a current breaker for switching on the main circuit. (3), the armature chopper control circuit (13) connected to the armature chopper (7), and the field chopper connected to the field chopper <10>. Control circuit (14) and tRr!i.

has been done.

Next, the operation of the above-mentioned conventional example will be explained with reference to FIG.

FIG. 3 is a characteristic diagram showing one line for speed-current characteristics of a DC shunt motor of a conventional electric vehicle control device.

In No. 30, the horizontal axis is the current, the vertical axis is the speed, IA is the armature current, 1. indicates the field current.

The speed control of electric cars is based on the armature current IA of the DC shunt motor.
and the field current I. Third
As shown in the figure, in general, in the low speed region T, the machine current I
Constant current control is performed to obtain a constant acceleration force by keeping A and field current (2) constant. When it comes to medium and high speed areas,
The field current is gradually weakened, and the electric car accelerates due to weak magnetic field control. In other words, the current in the field winding (9) is maximum in the low speed region, and at this time, thermal conditions are also severe.

In normal operation, the current flowing through the DC shunt motor is
It is controlled as shown in the figure, and there is no problem with the field winding a (9). However, if the electric vehicle attempts to accelerate with abnormal brakes applied due to a driving error by the driver, etc. In this case, the acceleration force becomes low and the speed of the electric vehicle does not increase. If the speed of the electric car is in the range of 1 or less (as shown in Figure 3), the balance L1 is reached, and if it continues to operate as it is, the maximum current will continue to flow through the field winding (9), and the field The temperature of the winding (9) has become abnormally high.
In the case of 1l FIB, it will lead to burnout.

[Problem to be Solved by the Invention 1] In the conventional electric vehicle control device as described above, when an electric vehicle attempts to accelerate with an abnormal overload applied to it,
There is a possibility of continuous operation with maximum field current,
Field volume 1! (9) There is a problem of temperature rise, abnormal overheating, and even burnout.

This invention was made in order to solve two consecutive problems, and is an electric vehicle control device that can prevent burnout and deterioration of field windings without installing a new temperature sensor etc. The purpose is to obtain.

[Means for Solving the Problems] An electric vehicle control device according to the present invention includes the following means.

(i>, Field chopper that controls the current flowing in the field winding of a DC motor.

(ii> A protection circuit that detects a temperature change in the field winding by a change in conductivity of the field chopper and stops the field chopper when the temperature of the field winding rises to a predetermined value.

[Operation] In the present invention, the field chopper controls the current flowing through the field winding of the DC motor.

Further, a change in temperature of the field winding is detected by a change in the conductivity of the field chopper by a protection circuit, and when the temperature of the field winding rises to a predetermined value, the field chopper is stopped.

[Embodiment PA] The configuration of an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and the current collector (2> to the field chopper control circuit (14)) are completely the same as those of the conventional device described above.

In FIG. 1, one embodiment of the present invention has a device that is exactly the same as the conventional device described above, and one input side is connected to a field chopper control circuit (14), and the other input side is an input terminal. (16) and whose output side is connected to the current breaker control circuit (12), the armature chopper control circuit (13), and the field chopper control circuit (14).
).

By the way, the protection circuit of the present invention is composed of a field chopper control circuit (14) and a comparator (15) in the above-described embodiment of the present invention.

Next, the operation of the above embodiment will be explained.

The field winding (9) of the DC shunt motor usually contains copper as a component, and the winding resistance value is expressed by the following equation.

Rt= (235'l-t) / (235+t o
)XR.

(Ω) ... ■ However, Rt: resistance value at temperature t, Ro: temperature 1,
where t is the temperature and to is the reference temperature.

Normally, the winding temperature is often based on 115°C,
The temperature rise limit of the winding wire is generally 180°C.

Now, t = 115, t = 115 + 180 = 2
95, Rt-(235+295>/(23
5+115) X R.

=1.51XR.

That is, in the normal operating state, the resistance value is Ro, whereas when the winding is at the temperature rise limit, the resistance value increases by about 50%.

On the other hand, the conductivity of the field chopper (lO) is expressed by the following equation.

γ, == I p' Rp/Ec,
,, ■Where, IF: field current, n: field resistance value, Ec: filter capacitor voltage.

From ■ and formula 0, when the temperature of the field winding (9) rises and the field resistance value RF changes, the field chopper (1
It can be seen that the conduction rate γ2 of 0) also changes.

Now, let the temperature tolerance limit of the field winding (9) be ts, and γFIl= ((235+ts) / (235+t
o) Let 1(rt,·I,/Ec1 be the detected conduction rate.

In Fig. 1, the detected conduction rate γF is determined by a microcomputer, etc.
a is input to the comparator (15) via the input terminal (16).

Under normal conditions, the temperature of the field winding (9) does not reach ts, so the comparator (15) does not operate.Due to some abnormality, the temperature of the field winding (9) "Unusually" Yu rises,
When ts is reached, the comparator (15) operates, and when it detects that γ, > γ, 8, the current breaker control circuit (12) and the armature chopper control circuit 1i'3 (13) and supplies a detection signal to the field chopper control circuit (14).

Then, each control circuit turns off the main circuit closing circuit breaker (3) and stops the armature chopper (7>) and the field chopper (10) based on the detection signal.

As described above, one embodiment of the present invention has a field winding (9
) can be detected by the conduction rate of the field chopper (1o), so it is possible to detect abnormal temperature rises in the field winding (9) at low cost without installing a new temperature sensor for the winding. This has the effect of being able to prevent this from happening.

In the above embodiments, a DC shunt-wound motor was described, but it goes without saying that the present invention is equally applicable to a DC compound-wound motor.

[Effects of the Invention] As explained above, the present invention includes a field chopper that controls the current flowing through the field winding of a DC motor, and a field chopper that controls the temperature change of the field winding by adjusting the current conductivity of the field chopper. and a protection circuit that detects the change and stops the field chopper when the temperature of the field winding rises to a predetermined value.
This has the effect of being able to prevent burnout and deterioration of the field winding without providing a new temperature sensor or the like.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing a conventional electric car control device, and Fig. 3 is a speed-current characteristic of a DC shunt motor of a conventional electric car control device. It is a characteristic diagram showing a curve. In the figure, (1... contact line, (2... current collector, (3... main circuit input circuit breaker, (4... filter reactor, (5... filter capacitor, (6 ) ... Armature winding, (7) ... Armature chopper (8) ..., Freewheel diode, (9)
... Field winding, (10) ... Field chopper (11) ... Freewheel diode, (12
)... Current breaker control circuit, (13>...
Armature chopper control circuit, (14)... Field chopper control circuit, (15)... Comparator, (16)... Input terminal. What! 3. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A field chopper that controls the current flowing through the field winding of the DC motor, and a temperature change in the field winding that is detected by a change in the conductivity of the field chopper, and the temperature of the field winding is set to a predetermined value. An electric vehicle control device characterized by comprising a protection circuit that stops the field chopper when the field rises to a certain level.