JPS591041B2 - Regeneration control device for DC electric cars - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC electric vehicle that performs p-regenerative braking operation using a chopper device, and relates to a regeneration control device for a DC electric vehicle that protects the chopper device against commutation failure. .

Conventionally, in a control device that drives an electric car, a cam-type contactor is used to short-circuit the starting resistor to control the power supplied to the DC motor, which is the drive motor, to control the speed of the electric car. However, with the development of semiconductor technology, a thyristor-type chopper with the function of directly interrupting direct current has been developed, which consists of a direct current interrupter and a freewheel diode. A DC power control device (hereinafter referred to as a chopper device) was developed, and by using this chopper device to smoothly control the DC power supplied from a DC power source, it was possible to improve the power consumption and riding comfort of electric cars. It is planned.

An electric vehicle driven by this chopper device can perform both continuous operation and regenerative braking operation by changing the connection of this chopper device.

In such operation, one of the things that particularly requires a protection circuit is chopper commutation failure.

This often occurs due to damage to circuit elements (for example, thyristors, commutating capacitors, etc.) constituting the chopper or failure of the control circuit that operates the chopper.

In particular, the situation is more severe in regenerative operation than in power-driven operation.

This is because during regenerative operation, the DC motor of the DC electric car serves as the power source for the regenerative brake, and the regenerative power is sent to the DC power source (overhead line side) while being controlled by the chopper device. When a current failure occurs, the DC motor during regenerative operation becomes short-circuited through the chopper, and the current flowing through the DC motor increases, resulting in a floodover (FIash over) on the commutator surface of the DC motor.
r) occurs and the DC motor is damaged.

To avoid this, one method of protection has traditionally been to divide the DC motors into two groups (usually 4 DC motors or 8 DC motors).
Since the tables are controlled by one set of chopper devices, they can be divided into two groups.

), among which the armature of the first group of DC motors and the field winding of the second group of DC motors are connected in series to form a first electric circuit,
Further, the field winding of the first group of DC motors and the armature of the second group of DC motors are connected in series to constitute a second electric circuit, and this first
The electric circuit and the second electric circuit are connected in parallel, and between these two electric circuits,
A short circuit device is provided so that the armature of the first electric path and the field winding of the second electric path constitute a closed circuit, and when a commutation failure of the chopper occurs, this is detected and the short circuit device is installed. The armature of the first electric circuit and the field winding of the second electric circuit and the armature of the second electric circuit and the field winding of the first electric circuit form closed circuits respectively, and each field winding is connected from each armature to each field winding. In addition, a field current is passed in a direction that reduces the induced voltage in each armature, and by suppressing the induced voltage in each armature to a low level, an increase in short-circuit current is prevented.

However, in a normal DC motor, in each field circuit, the generated magnetic field has a time delay of approximately 0.015 seconds to 0.02 seconds in response to a change in the current in the field winding.

If you operate the short circuit device using the method described above,
Even if the field winding current becomes zero, voltage remains in the armature, so extra current flows in the opposite direction through the field winding, and for the DC motor, only this extra current is required. The current flowing through the armature increases, making it difficult to commutate on the commutator surface.

The present invention has been made in view of these points, and in this invention,
By connecting a diode in series with each field winding, the current flowing in the field winding in the opposite direction due to the residual voltage of the armature is limited, thereby eliminating the above drawback.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the present invention. In the same figure, 10
indicates an overhead wire, 11 indicates a current collector (ordinary puncture graph), and 12 indicates a rail.Although not shown in this figure, there is a DC power source between the overhead wire 10 and the rail 12, and other DC electric cars are running there. ing.

21 is a filter reactor, 22 is a filter capacitor, and 21 and 22 constitute a DC filter.

3 is a chopper device, which is composed of a chopper 31 and a freewheel diode 32.

In the chopper 31, the terminal a represents an ignition terminal, and the terminal a represents an arc extinguishing terminal.

4 is a smoothing reactor, 5 is a motor circuit, the first DC motor is composed of an armature 51 and a field winding 52 forming a field circuit, and the second DC motor is composed of an armature 53 and a field circuit. The field winding 52 is composed of a field winding 54 and a field winding 52.
and armature 53 constitute a first electric path, and armature 51 and field winding 54 constitute a second electric path.

55 is the short circuit device divided by the short circuit device.

56 and 57 are diodes constituting the present invention, and the diode 56 is connected in series with the field winding 52, and the diode 5
7 is connected in series with the field winding 54, 5L52, 56°55 constitute a closed circuit, and 53, 55, 57, 54 constitute another closed circuit.

Further, the diode 57 blocks the current from 53 to 5 so that the diode 56 blocks the current from 51 to 52 to 56 to 55 to 51.
5→57→54→53 direction is connected so as to block the current.

6 is a chopper commutation failure detection device, which operates by detecting the terminal voltage of the chopper 31, and if the zero period of the chopper terminal voltage continues for a certain period or more, it is regarded as a commutation failure. commutation failure is detected.

The shorting device 55 is activated by the output signal from this detector.

FIG. 2 shows an example of the operation when a commutation failure occurs in a device configured as described above.

In FIG. 2, a is the voltage of the armature 51, b is the current of the armature 51, C is the current of the smoothing reactor 4, and d is the field winding 52.
shows the current of

When commutation failure occurs at time t, this is detected and the shorting device 55 is closed.

At this time, a voltage FM is generated in the armature 51 of the first DC motor in the direction shown by the arrow in FIG. 1, and a field current IF flows in the field winding 52 in the direction of the arrow. ing.

Due to this short circuit, the field winding 52 is connected to the armature 51 to 51.
Current flows through the circuit →52→56→55→51.

At this time, if the diode 5657 were not present, there would be a residual voltage in the armature 51 because the magnetic flux would remain even if the field current becomes zero due to the time delay between the field current and the magnetic flux. , current flows in the field winding 52 in the opposite direction.

The current in the armature 51 at this time is indicated by A in FIG. 2, and the current in the field winding 52 is indicated by C in FIG. 2 d.

The time t2 at which the current in the armature 51 reaches its peak and the time t3 at which the current in the smoothing reactor 4 reaches its peak are determined by selecting a large smoothing reactor 4 as shown in FIG.

As shown in C, t3 is later than t2.

On the other hand, as in the present invention, the diodes 56, 57
If the current in the field winding 52 is connected, the current in the armature 51 becomes zero as shown in the figure unless the current in the part shown by C in d in Fig. 2 flows. Figure 2 is middle B.
As shown in the figure, the smaller the size of B compared to A, the easier the commutation of the armature 51 is, and the less likely it is that fludge over will occur on the commutator surface, which will greatly help protect the chopper from commutation failure. be effective.

FIG. 3 shows another embodiment.

The same reference numerals as in FIG. 1 indicate the same parts, so the explanation will be omitted, but in this embodiment, a field weakening shunt circuit 52L54H (shunt resistor) is provided for the field winding 52,54. In the case where a field circuit is configured, diodes 567 and 571 are provided in series in the shunt circuit, and 56→ 521→561→52 direction and 57→
Diodes 561 and 571 are connected to block the circulating current flowing in the direction of 571→541→54.

By connecting diodes in this manner, even if there is a shunt circuit, sufficient protection against commutation failure can be achieved as in the case of FIG.

FIG. 4 shows another embodiment, and the same reference numerals as in FIG. In things,
A diode 560 common to the field winding 52 and the shunt circuit 521 connected in parallel is connected in series, and a diode 5 common to the field winding 54 and the shunt circuit 541 connected in parallel is connected in series.
70 are connected in series, and the diode 560 is 51 →
In this case, the diode 570 is connected in such a way as to block the current in the direction 2 560 → () → 55 → 51, and the diode 570 is connected in such a way that it blocks the current in the direction 53 → 55 → 4 570 → () → 53. Even in this case, it is possible to sufficiently protect against commutation failure as in the case of FIG. 1 or 3.

As described above, according to the present invention, as long as the reverse current in the field winding is controlled, the armature current is suppressed, making it difficult to cause a floodover on the commutator surface. It is highly effective for protection.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram showing one embodiment of the present invention, FIG. 2 is an observed waveform diagram of the required portion of FIG. 1, FIG. 3 is a circuit connection diagram showing another embodiment of the invention, and FIG. The figure is a circuit connection diagram showing another embodiment of the present invention. Note that the same reference numerals in the figures indicate the same parts. In the figure, 3 is a chopper device, 31 is a chopper, 32 is a freewheel diode, 4 is a smoothing reactor, 5 is a motor circuit, 51,
53 is the armature, 52.54 is the field winding, 55 is the short circuit device, 56° 57.560.570.561.571 is the diode, and 521.541 is the field weakening shunt circuit (shunt resistance). be.

Claims (1)

[Claims] 1 At least two DC motors are connected in parallel, and the armature of the first DC motor and the field circuit of the second DC motor are connected in series to form a first electric circuit, and , the field circuit of the first DC motor and the armature of the second DC motor are connected in series to form a second electric path, and the first electric circuit and the second electric path are connected in parallel, and between these two electric circuits The armature of the first circuit and the second
It is composed of a motor circuit provided with a short circuit device so that the field circuit of the electric circuit constitutes a closed circuit, a smoothing reactor connected in series with the motor circuit, and a chopper device that performs DC power control on the motor circuit, In the regeneration control device of a DC electric vehicle that performs regenerative braking operation using a chopper device,
A regeneration control device for a DC electric vehicle, characterized in that a diode is provided in series with each field circuit that constitutes a parallel circuit with the armatures of the first and second DC motors when the short circuit device operates. 2. Claim 1, wherein the field circuit has a field weakening circuit connected in parallel with the field winding, and a diode is provided in series with each of the field winding and the field weakening circuit. A regeneration control device for a DC electric vehicle as described in Section 1. 3. The field circuit has a field weakening circuit connected in parallel with the field winding, and a diode is commonly provided in series with the field winding and the field weakening circuit. The regeneration control device for a DC electric vehicle according to item 1.