JPH0759123B2 - Drive system for electric vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a drive system for an electric vehicle, and particularly to an improvement in a drive system for an electric vehicle including a DC motor driven by a pulsating current. .

[Conventional technology]

In general, a DC series-wound electric motor is used as a prime mover for driving an electric vehicle, and is normally fed from an overhead wire of a DC power source. However, in a special case, a step-down transformer and a rectifier are mounted on the vehicle, and power is supplied from an overhead line of an AC power source.

FIG. 8 is a diagram showing a vehicle drive system which is supplied with power from the overhead line of the AC power supply. In the figure, 1 indicates a vehicle,
Reference numeral 2 denotes an AC power line, and 3 denotes a rail.

On the vehicle 1, a transformer 5 for stepping down the AC voltage fed from the panda graph 4, a rectifying device 6 for converting the AC of the output of the transformer to DC, and a DC driven by the rectifying device are driven. A DC motor 7 is installed.

The DC motor 7 is a series-wound motor most suitable for vehicle drive control. Therefore, the DC motor 7 has a field winding 7f connected in series to the armature 7a as shown in FIG. It also has a field weakening device 7c in parallel with the field winding for speed control, that is, for weakening the field at high speeds.
The field weakening device is often formed by a resistor R and an inductor L.

In addition, in the case of receiving AC from the overhead wire of the AC power supply and converting it into DC on the vehicle in this way, it is difficult to obtain a sufficiently smoothed DC because it is a DC conversion of single-phase AC. It is supplied to the DC motor as it is. Therefore, to prevent pulsating current from flowing in the field winding 7f as much as possible, that is, to reduce the amount of transformer electromotive force generated, combine the resistor 7r in parallel with the field winding 7f (permanent component). The field device 7b) is used to shunt the field current.

As a related one, there is JP-A-49-82915.

[Problems to be solved by the invention]

When the vehicle is driven by the vehicle drive device formed in this way, even if it is a pulsating power source, the action of the permanent shunt device 7b reduces the transformer electromotive force, so to some extent the commutator part ( Electric motor) sparks are eliminated. However, in the direct-current motor driven by this kind of pulsating current power source, although the reason will be described later, there is a dislike for the low rectification performance due to the relationship between the transformer electromotive force and the residual reactance.

The present invention has been conceived in view of this, and an object of the present invention is that even if power is supplied from an AC power source, AC-DC conversion is performed on the vehicle, and the DC power source is a pulsating current. Even so, it is an object of the present invention to provide a drive system of this kind having a DC motor having a good commutation performance.

[Means for solving problems]

That is, the present invention provides a permanent shunt device in which a resistor and an inductor are connected in series in parallel with a series winding field winding, and the permanent shunt circuit is connected via the permanent shunt circuit at all rotation speeds of the DC motor. The current is shunted.

[Action]

With such a configuration, it is the vector sum of the combined spark voltage that greatly affects the rectification performance, that is, the residual reactance voltage that cannot be completely compensated by the compensating pole provided in the DC motor, and the above-mentioned transformer electromotive force. The synthetic spark voltage is reduced, the generation of sparks is suppressed, and the rectification performance can be improved.

〔Example〕

The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a diagram showing an electric vehicle equipped with the electric vehicle drive system of the present invention, and FIG. 2 shows an electric circuit of an electric motor which is a drive source thereof. In addition, the above-mentioned 8th
The same parts as those in the figure are designated by the same reference numerals, and the description thereof will be omitted here.

The major difference in these figures from the conventional one is that the permanent shunt device 7b (FIG. 2) is formed by a series circuit of a resistor 7r and an inductor 7l. That is, a permanent shunt device 7b is provided in parallel with the field winding 7f in parallel with the field winding. In particular, the permanent shunt device is a resistor 7r and an inductor 7l.
It is formed by a series circuit with.

With such a configuration, the spark voltage that causes a spark at the commutator portion can be reduced, and spark-free rectification is possible.

The reason why the spark voltage becomes small will be described below. For ease of understanding, the spark voltage of the conventional DC motor will be described first, and then the spark voltage of the DC motor of the present invention will be described.

FIG. 3 is a vector diagram showing the relationship between voltage and current in each part when a conventional DC motor is operated with a pulsating power supply. In this case, of course, it is assumed that the reactance voltage is compensated by the supplementary magnetic flux.

In the figure, I is an armature current, and there is a reactance voltage _Er with a phase shift of 180 degrees with respect to this armature current. Eφ is the compensating pole compensation voltage, and this compensating pole compensation voltage is β with respect to the armature current.
_The phase is delayed by _i . That is, theoretically, this phase shift does not occur and the reactance voltage is compensated by this compensating pole compensating voltage, but an eddy current occurs in the magnetic circuit of the compensating pole and due to this effect, the compensating pole compensating voltage Eφ is generated. Is deviated from the armature current by β _i . Of course, if the magnetic circuit is a laminated body of an extremely thin iron plate, this deviation, that is, β _i, will be considerably small and the reactance voltage will be compensated, but in practical use, the yoke which becomes a magnetic circuit due to the mechanical strength problem. Is a lump, that is, an iron cylinder, and an eddy current is inevitably generated. From these facts, the reactance voltage E _r is not completely compensated by the compensating pole compensation voltage Eφ, and E _S (reactance voltage E _{r in the} figure
And the residual reactance voltage shown as the vector sum of the compensating pole compensation voltage Eφ) remains.

In this way, the rectification effect is adversely affected by the residual reactance, but worse, the power supply current is pulsating direct current,
That is, power is supplied from the overhead power line of the AC power supply, and in the DC power supply rectified on the vehicle, a pulsating current remains even though it is a direct current, and this pulsating current also has an adverse effect on another rectification. is there.

That is, a pulsating magnetic flux of the main pole causes a transformer electromotive force (E _t ) in the field winding, and this transformer electromotive force causes deterioration of rectification.

The relationship of the transformer electromotive force will be described below with reference to FIG. First, for easy understanding, when referring to the case of resistance shunt in which a resistance is connected in parallel to the field winding, most of the pulsating current is because the reactance of the field winding 7f is sufficiently large with respect to the shunt resistance. The current flowing to the shunt resistance side and flowing through the field winding, that is, the field current _If becomes a delay current (phase difference θ _f1 , about 80 degrees) with respect to the armature current.

Therefore, the field flux φ _fr lags behind this field current I _f (phase difference β _f , about 70 degrees). That is, it is a delay caused by the presence of massive yokes in the magnetic circuit of the field pole.

From this, the transformer electromotive force E _t1 is 90 _% for the field flux φ _fr1 .
It becomes a vector that advances. That is, there is a delay of 60 degrees with respect to the armature current I.

Since this transformer electromotive force E _t and the above-mentioned residual reactance current E _S have an adverse effect on rectification, the vector sum of the combined spark voltage E _SP1 becomes a certain large value as shown in FIG. The value causes commutation deterioration in DC motor operation at pulsating current.

On the other hand, in the case of the present invention, that is, in the field winding 7f having the induction shunt 7l and the resistor 7r (see FIG. 2), the pulsating current also flows to the field winding 7f side. Fourth
As shown in the figure, the field current I _f2 has a small delay θ _f2 with respect to the armature current I. Therefore, the field flux φ _fr2 becomes a vector later than this field current I _f2 (phase difference β _f , about 70 degrees), and the transformer electromotive force E _{t2 leads} the field flux 90 degrees. Therefore, as much as the field current I _{f1 is transferred} to I _f2 , this E _t2 also moves and becomes the vector E _{t2 in the} figure.

Therefore, similar to the above, the transformer electromotive force that adversely affects the rectification
When E _t2 and the residual reactance current E _S are combined, the combined spark voltage S _P2 shown in FIG. 3 is obtained. This synthetic spark voltage ES _P2
It can be seen that is smaller than the synthetic spark voltage E _SP1 described above.

In practical use, the following good results have been obtained from the experimental results for confirming the effects of the conventional one and the present invention.

That is, the test motor has an output of 760 KW and a voltage of 850.
(V), current of 960 (A) (96% F) is selected,
With the conventional permanent shunt device, that is, with the resistance shunt (R = 0.04554 (Ω)), the number of sparks was 5, but with the present invention (L = 3.75 mH), The number of sparks was 3, and good results were obtained.

In the above description, one example is given for forming the permanent shunt device with the resistor and the inductor, but various other ideas may be considered.

Figure 5 shows another example. In the example of this figure, the permanent shunt device 7b is formed of a series circuit of a resistor 7r and an inductor 71, and of course, the resistance of the field weakening device 7c is also used. It could be miniaturized.

Also, FIG. 6 shows the value of the inductor 71 that can be adjusted.
If formed in this way, adjustment is possible even if an error occurs in the field magnetic flux path due to an assembly error of the electric motor, which is effective.

Although the example described above is an example in the case where there is a field weakening device, the present invention is not always applicable only when there is a field weakening device. For example, as shown in FIG. Even if there is no magnetic device, the same effect can be obtained by connecting the series circuit of the resistor 7r and the inductor 7l in parallel with the field winding 7f and always shunting the field current. Ah

〔The invention's effect〕

As described above, according to the present invention, a permanent shunt device in which a resistor and an inductor are coupled in series is provided in parallel with the series winding, so that the transformer voltage becomes the residual reactance voltage. Even in the case of an electric motor driven by a DC power supply with a pulsating flow, the synthetic spark voltage becomes small, and the drive system of this kind with less spark generation can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an electric vehicle drive system of the present invention, FIG. 2 is an electric circuit diagram of an electric motor which is a drive unit thereof, and FIGS. 3 and 4 are relationships among voltages, currents, and magnetic fluxes in respective parts of the electric motor. FIG. 5 to FIG. 7 are electric circuit diagrams of an electric motor showing another embodiment of the present invention, FIG. 8 is a diagram showing a conventional electric vehicle drive system, and FIG. It is an electric circuit diagram. 1 ... Vehicle, 2 ... Overhead line, 3 ... Rail, 4 ... Pandagraph, 5 ... Transformer, 6 ... Rectifier, 7 ... DC motor, 7a ... Armature, 7b ... Permanent component Path device, 7f ... field winding, 7r ... resistor, 7c ... weakening field device, 7l ... inductor.

 ─────────────────────────────────────────────────── ─── Continued Front Page (56) References JP-A-57-177202 (JP, A) JP-A-61-185086 (JP, A) JP-A-58-130705 (JP, A) JP-B-63- 32028 (JP, B2)

Claims (4)

[Claims] 1. A transformer fed from an overhead line of an AC power supply,
A rectifier that converts the AC output of the transformer into a DC, and a DC motor that is driven by the DC output of the rectifier, wherein the DC motor includes a series winding field winding and the series winding field winding. A drive system for an electric vehicle having a wire and a permanent shunt device connected in parallel, wherein the permanent shunt device is formed by a series coupling circuit of a resistor and an inductor. Drive system. 2. A transformer fed from an overhead line of an AC power supply,
A rectifier for converting the AC output of the transformer into a DC and a DC motor driven by the DC output of the rectifier, wherein the DC motor is a series winding field winding and the series winding field winding. In a drive system for an electric vehicle having a permanent shunt device connected in parallel with a wire and a field weakening device coupled in parallel to the series field winding, the permanent shunt device is a resistor and an inductor. A drive system for an electric vehicle, characterized in that the drive system is formed by a series connection circuit with an electric device. 3. The electric vehicle drive system according to claim 2, wherein the inductor of the permanent shunt device also uses a part of the inductance of the field weakening device. . 4. The drive system for an electric vehicle according to claim 2, wherein the inductor of the permanent shunt device is formed so that its inductance value can be adjusted.