JPH011402A - Main circuit of regenerative brake type AC electric car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a main circuit of a regenerative brake AC electric vehicle among railway vehicles.

[Conventional technology]

The regenerative braking method is a method in which the electric motor acts as a generator during the braking period, and the generated power is regenerated into the power source to obtain the required braking force.

Therefore, during the braking period, the direction of the induced electric power in the armature must be changed to the opposite direction to that during moving. For this reason, the field winding of the motor is generally separately excited by a separate power source, and the polarity of the field winding is changed using a switch.

In this way, when the field winding is separately excited, when multiple motor armatures are connected in parallel, it is possible to balance unbalanced currents that occur due to differences in motor characteristics or variations in axle diameter due to tread surface grinding, etc. A tool will be needed.

Therefore, the main circuit of the conventional AC electric car with regenerative braking, Fuji Jiho VoQ, 56 N (131983 "R5932 type main control rectifier for Shinkansen AC regenerative braking device")
As described in , in order to balance the current unbalance of two parallel motor circuits, two sets of thyristor bridges, two transformer secondary windings, and a control device that commands unbalance detection and phase control are used. There are some that have.

FIG. 5 is a circuit diagram showing its configuration. FIG. 5 shows a configuration in which four armatures All to A24 of eight main motors MM are connected in series, and two armatures are further connected in parallel.

In the figure, the primary winding P of the main transformer MT mounted on the electric car is pear-shaped by the pantograph PT from the overhead wire CW.
The other end is grounded to the rail RL through the wheel W.

The secondary winding is divided into four parts Ll=La. This is because the secondary side is generally divided into 4 to 6 parts to reduce harmonic current. The secondary windings divided in this manner are set so that a voltage e is induced per winding, and the rated electric vehicle performance can be obtained with the ex4 winding. Further, unbalance adjustment windings Q1-2 are provided on the secondary side of the main transformer MT, and Δ
A voltage of e is induced.

The voltage and current of these secondary windings are the main syrisk bridge M
Rfz-a and unbalance adjustment thyristor bridge MRf
The phase is controlled by Δl~2 and converted into a pulsating flow,
The main smoothing reactors M S L 1 to 2 smooth the pulsating current to an appropriate rate required by the main motor MM, and supply it to the armatures Azt to 24.

On the other hand, the main transformer MT is provided with a field power supply winding B in order to supply power to the field winding MFrt~24 of the separately excited main motor MM.

A field power supply thyristor bridge ARf is connected to the winding B, which converts AC power into DC power and supplies it to the main motor field winding MFrt~24.

Switches Rp and Ra are provided between the field winding MF1t-z4 and the thyristor bridge ARf, and the direction of the induced electric power of the armature A11-■ during power running and braking is the direction of arrow Dp during power running. , when braking, the direction is changed to the direction of arrow Dn.

By the way, although the control circuit is omitted in Fig. 5, 1
Only control parts related to the present invention are shown.

In other words, armatures Axx~14 and A are connected in parallel.
DC converters D CCT 1 to 2 are provided between 11 to 24 to detect the load current It to 2, and comparators cl and Cz are connected to the output side of the DC converters D CCT 1 to 2 to detect the load current It to 2. A comparison is made with a pattern generated by a pattern generator PG according to a command.

Based on this comparison result, mobile phase unit AP1. A signal for balancing the load currents 11-2 is sent from APz to the gate of the unbalance adjustment thyristor bridge MRfΔl-2 via the pulse transformer Tl-z.

In this configuration, when the electric vehicle is powered, speed control is performed by changing the DC voltage applied to the armatures All to 24 by phase control of the thyristor garage MRfl-a.

That is, as shown in FIG. 6, the transformer secondary winding L I
K-connected thyristor bridge M Rf 1 from control angle = 180° (OFF state) to control angle = O.

The no-load DC voltage is increased to KXe (V).

After this, MRf 1 has a control angle of 0'', that is, it operates like a diode, and then MRf 2 is similarly phase controlled to raise it to KX2e, and thereafter, the voltage is increased by sequentially controlling it to MRf a. and increase the speed.

On the other hand, armatures A I 1 and 2 and Azt connected in parallel
- 2, there may be a difference in the load currents 1 and 2 due to differences in characteristics of the main motor MM, differences in wheel diameters, etc., resulting in unbalance.

Il and I2 are detected by the DC current transformer D CCT s~2 and are compared with the pattern sent through the pattern generator PG by the notch signal from the master controller MC and the comparators C1~2.
The phase shifter A P t~2 passes the phase control angle signal through the pulse transformer Tr~2 to MRfΔl~
Δe (V) so that the voltage sent to the gate of 2 and applied to Al1-14 and Azt~24 becomes Ix = Iz.
It is designed to be controlled within

On the other hand, in the field winding MFxz-an, switch RP
is closed, and the fIt machine induced voltage is in the Dp force direction.

Next, during braking, in order to regenerate electric power to the power source, field winding MFzt ~ 2 switch Rp is opened and Ra is closed, and the induction when armature Alt ~ 24 acts as a generator is The direction of power is changed to the direction of DB.

Thereafter, the main thyristor MRf is operated by an inverter, and the generated power is regenerated as a power source to obtain braking force.

Regarding current unbalance between armatures Azt~14 and A21~24, current balance control is performed by detection comparison and phase control on the unbalance adjustment sirisk bridge MRfΔl~2 using a phase shifter, as in the case of power running. .

[Problem that the invention seeks to solve]

However, with the configuration described above to balance unbalanced currents, it is necessary to install a 2#fl transformer, a converter (Sirisk bridge), and its control device for unbalance adjustment, so the single regenerative braking method is not used. There is a problem in that the number of parts and semiconductors are increased compared to the previously widely used dynamic braking system, resulting in a significant increase in cost.

The object of the present invention is to reduce the number of components, especially the number of semiconductor elements,
An object of the present invention is to provide a main circuit for a regenerative brake type electric vehicle that can reduce costs.

[Means for solving problems]

The above object is achieved by utilizing the current balancing effect of a reactor with a center point instead of balancing control using a thyristor bridge.

[Effect]

In a reactor with a midpoint, a load current is passed through the midpoint, and if the alternating current sides of two parallel converters are connected to the other ends, a divided load current will flow.

In the case of equilibrium, the induced magnetic flux is equal and 180
Since the directions are different, they cancel each other out. In other words, it becomes an uninduced state and the inductance becomes zero. On the other hand, when an unbalanced current flows, the magnetic fluxes are not canceled out, and an induced voltage corresponding to the unbalanced current is generated, and the direction of the circulating current flows in the direction and magnitude in which the unbalanced current is balanced. As a result, the reactor with a center point performs the unbalance detection and balancing function by itself, and as a result, the unbalance between the two parallels is eliminated.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which the primary side and field power supply side of the main transformer MT have exactly the same configuration as the conventional example, and the secondary side has the same configuration as the conventional example. The raw voltage = 4e' = 4e for each differential L, /~4'
It is configured so that +Δe can be obtained.

On the other hand, the main thyristor bridges MRfz'~3 are connected with one unit per winding, and in the final stage winding number L12, the thyristor bridges MRf'4t and MRf'42, which have a negative current capacity of MRfz'~3, have two units. The center point of the reactor LB with a center point is connected to the antithyristor (Ill) of the L1 winding.

This results in a parallel configuration as shown below.

Upper half of BL → MRf'4t → M S L 1 → Att
~14/ L+4 winding\ Lower half of BL → MRf'az → MSL2 → Azt ~24
Next, the operation of the present invention will be explained with reference to FIGS. 2 to 4.

As shown in FIG. 2, phase control is sequentially performed from M Rf' 1 and speed and brake control are performed in the same manner as in the conventional example during both driving and braking. However, in the configuration of the present invention, the load current As shown in Fig. 3, the reactor BL is divided into two sides, A and B, through the center point C of the reactor BL with a center point.
It flows as 2.

If the electric current flows on the A side, the current I flows on the B side! (If > I2), the difference current (I
The magnetic flux Φ due to ~I2) generates an electromotive force E as shown in the vector diagram of FIG. 4, which generates a circulating current Is shown by a broken line in FIG.

As shown in FIG. 4, Is flows in the direction of decreasing It and increasing I2, that is, 11=Iz.

Therefore, if we look at the system action in the main circuit with the configuration shown in Figure 1, we can see that if there is
14 and A21-24) become unbalanced and become 11f-IQ, the wi ring current Is flows as 11=I2 due to the action of the reactor BL with a midpoint as described above. , the current between the two parallels is 11=I
It comes to be in equilibrium with z.

That is, according to this embodiment, Q1~z, MRfΔl~2°DCCTs for unbalance adjustment in the conventional example
-z + Ch-2, API-2, Tl-2 omitted,
It becomes possible to replace it with a reactor BL with a midpoint.

〔Effect of the invention〕

As described above, according to the present invention, there is provided an unbalance adjustment winding of a transformer and an unbalance adjustment thyristor bridge.

It eliminates the need for an unbalanced current detection device and a gate control device for the unbalanced adjustment thyristor, reducing the number of parts by a large number of parts, resulting in significant cost reductions and improved reliability. It will be done.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
An explanatory diagram for explaining the relationship between the control of each winding and the silis bridge and the output voltage in the embodiment shown in the figure, and Figures 3 and 4 are diagrams for explaining the operation of the reactor with a center point used in the present invention. FIG. 5 is a circuit diagram showing the configuration of a conventional main circuit, and FIG. 6 is an explanatory diagram for explaining the relationship between control of each winding and thyristor bridge and output voltage in the conventional main circuit. MT...Main transformer, MRf 1~a, MRft~4
'...Main thyristor, BL...Reactor with center point,
L1~4゜Ll"4'...Transformer secondary winding, I, I
B... Load current, IS... Circulating current, G... Unbalance adjustment winding of transformer, MRfΔ... Thyristor bridge for unbalance adjustment. MM... Main motor, A11-24... Armature of the main motor, MFrt~24... Field winding of the main motor.

Claims (1)

[Claims] 1. In a regenerative brake type AC electric vehicle in which two plurality of separately excited electric motors are connected in parallel and are driven via a transformer and two sets of converters, a reactor with a center point is disposed between the transformer and the converter. The middle point of the transformer is connected to one end of the secondary winding of the transformer, and the other terminals are connected to the alternating current sides of the two sets of converters, and the unbalanced current generated between the two parallel motor circuits is A main circuit of a regenerative brake type AC electric vehicle characterized by being configured to achieve balance.