JPS6016183A - Regenerative brake controller - Google Patents

Abstract

PURPOSE:To reduce a current interruption frequency near the rated current of a switch upon operation of a regenerative brake by starting a control at brake OFF time from the stop of the operation of a chopper. CONSTITUTION:When a brake OFF is instructed and a signal is outputted from a brake command controller 10, this signal is applied to a switch 5. When the switch 5 is opened, the signal is supplied to a switch 6. The amplitude of an armature current of a main motor 1 is controlled by the ratio of the ON period of a chopper 8 to the OFF period. The opening timing of the switch 5 is delayed after the timing of turning the chopper 8 OFF.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a regenerative braking device for a DC motor using a semiconductor chopper, and particularly to a regenerative braking control device with improved control characteristics when regenerative braking is released.

[Background of the invention]

With the advancement and improvement of semiconductor switching devices such as thyristors and GTOs, various types of eyelid devices have come to be widely used for controlling DC motors.

An example of a regenerative braking control device for an electric vehicle using such a chopper device is shown in Figure 1.

This figure 1 shows the main circuit connection and the flow of control signals at this time when the traction motor is controlled to regenerative braking mode 111. In this figure, 1 is the armature of the traction motor, and 2 is the main circuit connection and the flow of control signals at this time. The field winding of the main motor, 3 is a smoothing gate, 4 is a diode, 6 is a switch, 7 is a pantograph, 8 is a chopper, 9 is a thyristor used in the chopper 8,
A gate control section 10 controls the gate of a switching element such as a GTO, and a brake command control section 10 generates a brake on/off signal instructing the activation and release of the brake in response to a brake operation. In addition, ■ is the brake command output signal output from the brake command control unit 10,
■ is output from the switch 5 and outputs an operation confirmation signal to confirm the operation of this switch 5, ■ also attenuates the operation confirmation signal of the switch 6, and IA outputs the armature current in the regenerative braking state. represent.

Next, the operation of this device will be explained.

Now, when the brake handle is operated and a brake operation is commanded, a signal is sent to the brake command control unit 10.
The command section 10 outputs a brake command output signal {circle around (2)}.

゛ As a result, signal ■ → ON operation of switch 5 → signal ■ →
The control progresses sequentially in the following order: ON operation of the switch 6 → signal →→'−) Start of gate control signal generation operation of the control unit 9 → start of operation of the chopper 8, and the main motor enters the regenerative braking state and applies brake torque. caused to occur.

The operation in the regenerative braking state is as follows.

When a brake operation is commanded, the main motor is forcibly rotated from the load side, and the armature 1 generates an electromotive force □ due to residual magnetism present in the magnetic circuit.

Therefore, if chopper 8 is now in the ON period, armature 1 → field winding 4112 → reactor 3 → chopper 8 → switch 5 → i! A short circuit consisting of the armature 1 is formed, and an armature current IA flows due to the self-excited power generation characteristics of the main motor.

Next, the chopper 8 is controlled to be turned off when the armature current has reached a predetermined value. Then, the armature current IA flowing during the ON period of the chopper 8 mentioned above
As a result, a back electromotive voltage is generated in the reactor 3, and the sum of the back electromotive voltage of the reactor 3 and the generated voltage of the armature 1 becomes higher than the power supply side voltage (overhead M voltage), so the earth → switch 5
→ Armature 1 → Field winding 2 → Reactor 3 → Diode 4
The armature current IA flows through the path of → switch 6 → pantograph 7 → overhead wire, and regenerative power is sent to the power supply side, allowing the main motor to obtain regenerative braking torque.

On the other hand, when the chopper 8 enters the regeneration state during the off period, the back electromotive force of the reactor 3 decreases for a while, and when the sum of the back electromotive force of the reactor 3 and the generated voltage of the armature 1 becomes less than the overhead line voltage, regeneration begins. Current stops flowing and regenerative braking torque also becomes zero.

Therefore, if the chopper 8 is turned on again, the armature current I
A increases, and then by turning off the chopper 8, regenerative braking can be performed again.

Therefore, by turning the chopper 8 on and off at a predetermined period, it is possible to perform a nearly continuous regenerative braking operation, and the magnitude of the regenerative braking torque at this time is the difference between the on period and the off period of the chopper 8. It is possible to arbitrarily control the ratio, that is, the distribution rate.

In addition, the on/off period of the chopper 8 at this time can be made considerably short (about several KHz in terms of li11 wave number) by using a GTO as a switching element, and in this case, the on/off period of the chopper 8 Even if it is not provided as a separate device, a sufficient regenerative voltage can be obtained only by the inductance existing in the short circuit internal pressure including the armature 1, and the reactor 3 can be made unnecessary.

Next, when the brake handle is returned and brake release is commanded, a signal ■ to turn off the brake is output from the brake command control unit 10, and the signal ■ → OFF operation of the switch 5 → the signal ■ → the switch 6 OFF operation → signal ■ → gate control unit 9 gate) Control signal generation operation stop → chopper 8
The control operation moves in the order of operation stop 1, and the regenerative braking operation is stopped.

The operation at this time is shown in a timing chart as shown in FIG. 2. At time t, brake off is commanded and the signal 1 is output. After that, the operation delay time τ of the switch 5
At time t1, when 1 has elapsed, the switch 5 is turned off, and at the same time, the signal ■ is generated. Similarly, the operation delay time τ of the switch 6! The time t! has passed! The switch 6 is turned off, the signal ■ is generated, and the chopper 8 stops operating.

Therefore, in the conventional device shown in FIG. 1, as is clear from FIG. 2, the armature current is always cut off by the switch 5 when the brake is off.
This has disadvantages in that the frequency of interruption at a current close to the rated current value of the switch 5 increases, increasing maintenance and inspection work, and making it impossible to prolong its service life.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a regenerative braking control device that reduces the frequency of current interruption near the rated current of a switch due to regenerative braking operation, and eliminates the drawbacks of the prior art described above. There is something to do.

[Summary of the invention]

In order to achieve this object, the present invention is characterized in that control when the brake is off starts from the stoppage of the operation of the chopper device.

[Embodiments of the invention]

Embodiments of the regenerative braking control device according to the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention. Although the main circuit configuration is the same as that of the conventional example shown in FIG. The ON input for starting the operation is given by the signal ■, but the OFF input for stopping the operation of the gate control section 9 (that is, keeping the chopper 8 off) is given by the signal ■. .

Next, the operation of this embodiment will be explained with reference to the timing chart of FIG. It goes without saying that the regenerative braking operation can be obtained in the same manner as in the conventional example shown in FIG.

Now, time t. It is assumed that the brake is commanded to turn off and the signal ■ is output from the brake command control section 10. Then, this signal is given to the switch 5 as in the conventional example shown in FIG. 1, and when the switch 5 is turned off, the signal (2) is supplied to the switch 6. However, at this time, the switch 6 is turned off, so the signal (2) in response to the ON input of the gate control section 9 is not generated.

On the other hand, in this embodiment, when the signal ■ is output at time to, this signal ■ is also supplied to the OFF input of the gate control section 9, so that the gate control section 9 stops operating at time to, and the chopper 8 is time t. Thereafter, the armature immediately shifts to the off state, and the short circuit including the armature 1 is turned off.

Therefore, the armature current IA decreases at a predetermined time constant after time to, and when the sum of the back electromotive force of the reactor 8 and the generated voltage of the armature 1 becomes slightly higher than the overhead line voltage, the The child current IA becomes zero.

Therefore, now, after the chopper 8 is turned off, the armature current I
Let τ0 be the time until A becomes zero, and this time τ. If it is possible to prevent the switch 5 from becoming longer than the operation delay time τ1 of the switch 5, when the switch 5 is turned off at time t1, the armature current IA is zero, so the switch 5 is turned off without interrupting the current. Finish the operation.

Therefore, the decay time τ of the armature current IA at this time. is determined by the characteristics of the main motor, the voltage generated by armature 1 during regenerative braking, the inductance and resistance values of the main circuit, etc., and from a practical standpoint, the above conditions, that is, τo and τ1 must be satisfied. Therefore, according to this embodiment, the degree of current interruption by the switch 5 during regenerative braking can be reduced to almost zero.

FIG. 5 is a diagram showing FIG. 4 in more detail, at time t. Previously, the regenerative braking state was indicated, and the armature current IA was chopper 8.
The rise in the on period and the fall in the off period are periodically repeated, and the magnitude of this armature current IA is determined by the chopper 8.
is controlled by the ratio of on-period to off-period. In addition, in this state, the regenerative current that flows through the diode 4 and from the bank grapher 77 to the overhead wire is represented by IB, and this current flows only while the chopper 8 is off. At time t0, the chopper 8 stops operating (remains off), and after this time t0, the armature currents IA and IB have the same value, and have a damping characteristic determined by conditions such as the characteristics of the main motor described above. Time τ. Later it becomes zero.

Next, FIG. 6 shows another embodiment of the present invention, which differs from the embodiment shown in FIG.
The point is that the signal (2) outputted from 0 is not supplied to the switch 5, but is directly supplied to the switch 6. Note that the signal when the brake is on is omitted.

Therefore, the operation when the brake is off in this embodiment is as follows:
As shown in FIG. 2, since the switch 5 does not turn off when the brake is off, the switch 5 only turns off when the brake is off, and the frequency of the switch 5 turns off can be sufficiently reduced.

Furthermore, as is clear from FIG. 5, in this type of regenerative braking device, the regenerative current IB after the chopper 8 operates is equal to the armature current IA.

Therefore, in this embodiment as well, wL after time to
Decay time t of armature current IA. By making the off-operation delay time τ of the switch 6 smaller, it is possible to prevent the switch 6 from cutting off the current when the brake is turned off. In addition, in this embodiment, when the switch 6 interrupts the current, that is, when it turns off before the regenerative current IB reaches zero, due to the inductance included in the circuit such as the reactor 3, the difference due to d/dt is A high voltage is generated and an overvoltage is applied to the chopper 8.

Therefore, in this embodiment, it is necessary to ensure that the above-mentioned condition of τ o - rl is sufficiently maintained.

Next, Fig. 8 uses a DC shunt motor as the main motor,
This is an embodiment in which a field chopper control method is applied, and in the figure, Sll is a chopper for field control, 12 is a gate control section thereof, and 13 is a diode for circulating current. Note that IF represents the field current, and the rest is the same as the embodiment shown in FIG.

The operation of the embodiment shown in FIG. 8 is as follows.

When the brake is on, the brake command control unit 1° → signal ■
Control proceeds in the order of → switch 6 → signal ■ → gate control unit 9.12 → chopper 8.11, and regenerative braking operation begins. In this state, during the ON period of chopper 8, armature 1 → reactor 3 → chopper 8 → switch 5 → armature 1,
Armature current IJL flows in the circuit, and the current value increases during this period, and during the off period of chopper 8, 1 earth → switch 5 → armature 1 → reactor 3 → diode 4 → pantograph 6 → A regenerative current is generated in the overhead line circuit, and the current value decreases during this period.

Further, in parallel with this, the chopper 11 is also turned on and off at a predetermined cycle to control the field current IF. During the period when the chopper 11 is on, the operation at this time is as follows: overhead line → pantograph 7 → switch 6 → field winding 2 → chopper 1
The value of the field current IF is increased by the circuit of 1→earth, and during the period when the chopper 11 is off, the value of the field current IF is increased by the circuit of field winding 2→diode 13→field winding 2. Attenuate.

Therefore, according to this embodiment, by controlling the flow rates of both choppers 8 and 11, it is possible to control the magnitude of regenerative braking torque by the main motor.

Next, when the first brake is off, the brake off command signal (■) generated from the brake command control section 10 is sent to the gate control section 9.
12 and the switch 6, and as in the case of the embodiment of FIG. 6, as shown in FIG. 7, the time t when the brake-off command is generated. Thereafter, both the armature current IA and the field current IF are attenuated, and the switch 6 is turned off without cutting off the current, and no overvoltage is generated.

Therefore, according to this embodiment as well, it is possible to reduce the frequency of the OFF operation of the switch 5, and it is also possible to reduce the frequency of the current cut-off operation of the switch 6.

In the case of this embodiment of the 8th wJ, the size difference of the field current r is usually considerably smaller than the size of the armature current IA, and for this reason, the switch 6 is When only the field current IF is cut off, there is little risk of overvoltage occurring, and the life of the switch 6 is hardly affected. Therefore, in the case of the field chopper control system as in this embodiment, the chopper 11 may be configured not to be controlled when the brake is off, and the object of the present invention can also be sufficiently achieved by this K. It is possible to simplify the traverse.

Here, to show an example of the decay time τ0 of the armature current IA in the above embodiment, the voltage difference between the overhead line voltage and the armature generated voltage is 50 [■], and the inductance in the short circuit is 2 ( mH),! The initial value of 4m child turtle style IA is 500
(If A”l, dI/dt of this armature current IA
is approximately 25000 [: A/S], and τ. Things
[:ms]. Moreover, as explained in FIG. 5, after time to, the state is IA-IB.

Therefore, in the above embodiment, if the off-operation time of the switch 5 or the switch 6 is 20 (ms) or more, the effects of the present invention can be sufficiently exhibited.〇 [Effects of the Invention] As explained above, according to the present invention, it is possible to reduce the frequency of the opening operation of the switch during regenerative braking control, thereby eliminating the drawbacks of the conventional technology and shortening the service life of the switch due to the regenerative braking operation. To easily provide a regenerative braking control device that does not require an increase in maintenance and maintenance, has a simple circuit for controlling a switch, requires fewer auxiliary devices such as relays, and is useful for lowering costs and improving reliability. I can do it.

[Brief explanation of drawings]

Figure 1 is a main circuit connection diagram showing a conventional example of a regenerative braking control device, and Figure 2 is a timing chart for explaining its operation.
The figure is a main circuit wiring diagram showing one embodiment of regenerative braking control according to the present invention, Box 4 and Figure 5 are timing charts for explaining its operation, and Figure 6 is a diagram showing another embodiment of the present invention. FIG. 7 is a timing charge diagram for explaining its operation, and FIG. 8 is a main circuit diagram showing still another embodiment of the present invention. 1... Armature of the traction motor, 2... Field winding of the traction motor, 3... Reactor, 4...
...Diode, 5.6... Switch, 7...
...Pantograph, 8,11...-Chopper%9-12...Gate control section, 10t1st 2
3rd figure Sai 2fu 4th year old 5th time Muo 6th off eye Mudoha -1111] Year 8th figure

Claims (1)

[Claims] 1. A switching device is provided to turn on and off a short circuit of a DC motor in a generating state, and a regenerative voltage is generated by the sum of a back electromotive force due to an inductance included in this short circuit and a generated voltage. In a regenerative braking device that generates regenerative current and supplies regenerative current to the power supply side via a diode,
1. A regenerative braking control device, characterized in that the timing of an opening operation of a switch in a regenerative current path when regenerative braking is stopped is later than the timing of stopping a switching operation of the switching circuit. λ A regenerative braking control device according to claim mx, characterized in that a field winding of the DC motor is included in the short circuit. 1. The regeneration according to claim 1, wherein the DC motor is equipped with a field chopper control device, and is configured to reduce the field current to zero at the timing of stopping the switching operation of the switching circuit. Braking control device.