JPH0755008B2 - Control method for DC shunt field motor for vehicle - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention controls a DC shunt field motor used as a main motor for a railway vehicle, for example, by controlling the armature and the field winding via a chopper. The present invention relates to a method for controlling a DC shunt field motor for a vehicle.

[Technical background of the invention and its problems]

FIG. 3 shows the main circuit configuration of a DC shunt field motor used in railway vehicles. 1 is a pantograph, 2 is a wheel, 3 is an input filter reactor, and 4 is an input filter capacitor. Further, 5 is an armature 6 and a field winding 7
Is a DC shunt field motor, 8 is an armature chopper connected in series with the armature 6, and 9 is a flywheel diode connected across the armature 6. Further, 10 is a field winding 7 of a DC shunt winding field motor (hereinafter referred to as an electric motor) 5.
It is a field chopper that controls the field current applied to the.

In such a configuration, when powering, the conduction ratio of the armature chopper 8 is α, and the conduction ratio of the field chopper 10 is
Control is performed so that the field current IF is maintained at a predetermined ratio with respect to the armature current IA.

FIG. 4 is a block diagram showing a conventional control method of the conduction ratio α of the armature chopper 8, 11 is an armature current command value calculation unit, 13 is a feedback control unit, 14 is a damping control unit, 15 Is an adder. The armature current command value IC calculated by the armature current command value calculation unit 11 is the feedback control unit 13
Given to. The feedback control unit 13 is configured as shown in FIG. 5, and has a deviation ΔI between the command value IC and the armature current IA.
Is calculated by a subtracter 19, and this deviation ΔI is further increased by a first-order lag element 20 to obtain feedback conduction ratio α ₂ = K ₀ /
Get (1 + T ₀ · S). Where K ₀ is the amplification gain and T ₀
Is the delay time constant. On the other hand, the damping control unit 14 enhances transient stability, and the feedback control unit 13
Prevents hunting that cannot be suppressed by itself. FIG. 6 shows the details of the damping control unit 14. The differentiator 21 differentiates the armature current IA and the differentiator 22 differentiates the filter capacitor voltage.
EC is differentiated, respective outputs α ₃₁ and α ₃₂ are given to the subtractor 23, and α ₃₁ is subtracted from α ₃₂ to obtain the damping conduction ratio α ₃ . Then, the feedback conduction ratio α ₂ and the damping conduction ratio α ₃ are added by the adder 15 to obtain the armature chopper conduction ratio α.

By the above control, the armature current IA is roughly the armature current command value.
Although controlled equally to the IC, this method had the following drawbacks.

The responsiveness of this control mainly depends on K ₀ and T ₀ , and the larger K _{0 and the} smaller T _{0, the} faster the response. On the other hand, however, stability is a reciprocal relationship, and it is difficult to maintain a stable response without sacrificing stability and to large disturbances such as sudden changes in the bridge voltage of the vehicle for the following reasons. Is.

As shown in FIG. 3, the circuit of the armature chopper 8 of the DC shunt winding motor 5 has no field winding and the main smoothing reactor is removed. Therefore, the impedance of the circuit is only that of the armature 6. Yes, the impedance is extremely small compared to a chopper circuit using a DC series winding motor. Therefore,
The armature chopper 8 is required to have an extremely high-speed response to a change in the overhead wire voltage, and it is impossible to achieve both stability at the same time.

As a method for improving this, there is a method as shown in FIG. FIG. 7 shows the control block diagram of FIG. 4 with a feedforward control unit 12 added.

Details of the feedforward control unit 12 are shown in FIG. 8 and the operation thereof will be described.

The function unit 24 has the magnetization characteristics of the electric motor as a function,
When the field current IF is input, the field flux KΦ is obtained. Then, the multiplier 25 multiplies this field magnetic flux KΦ by the motor rotation speed VLC to obtain the motor back electromotive force EM. When the armature resistance of the motor is R, the conduction ratio α ₁ for making the armature current command value IC and the armature current IA equal when the filter capacitor voltage is EC is Given in. The function unit 26 runs this calculation, and outputs the result as the feed-forward conduction ratio α ₁ .
This is called feedforward control because the armature current IA is not used in the process of obtaining α ₁ .

Obtaining α ₁ in this way calculates and outputs the duty factor at which IC = IA at all overhead line voltages and rotation speeds. Therefore, even if EC changes suddenly due to a sudden change in overhead line voltage, it is appropriate. IA will be ordered, and the IA
Does not deviate significantly from IC.

The obtained α ₁ is the feedback conduction ratio α if the characteristics of the motor circuit completely match the values used in the calculation.
_{Even if 2} is not present, IC should be IA, but in reality IC does not necessarily become IA due to the deviation of the magnetization characteristics, the temperature change of the armature resistance value R, and so on. Therefore, in order to correct this, the feedback control unit 13 is still necessary in FIG. 7, but its role is merely constant current correction, and almost all absorption of steep disturbances such as abrupt changes in the overhead line voltage as described above. Since the feedforward control unit 12 takes charge, the internal first-order delay gain K ₀ does not need to be so large and the delay time constant T ₀ can be set to a sufficiently large value. That is, it is not necessary to force a fast response at the expense of stability.

However, the method of FIG. 7 also has the following problems. That is, at the time of startup, α is the feed-forward conduction rate α ₁
Is output in a stepwise manner, and as described above, when correction by the feedback conduction ratio α ₂ is necessary due to characteristic deviation, etc., especially when α ₁ alone opens the phase too much, There is a high possibility of causing overshoot of current and causing overcurrent.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object thereof is to ensure sufficient stability and quick response as armature current control characteristics during power running, and to cause current overshoot at startup. Another object of the present invention is to provide a method for controlling a DC shunt field motor for a vehicle.

[Outline of Invention]

In order to achieve the above object, the present invention is such that, when the rate of change of the flow rate command value exceeds a predetermined value, the actual flow rate is converged to the flow rate specified value according to the predetermined value. .

Example of Invention

FIG. 1 shows an embodiment of the present invention, in which a change limiter 16 is added to the control block diagram of FIG.

This change limiter 16 changes the change rate dα of the flow rate command value α _0.
0 / dt is limited to a predetermined value C ₁ or less. That is,
As shown in FIG. 2, the flow rate command value α ₀ changes stepwise (t ₁ , t ₃ ), or changes rapidly (t ₅ ), and the rate of change dα ₀ / dt is predetermined. When the value exceeds the value C ₁ , the actual flow rate α is changed by a predetermined value C ₁ , and this is continued until it becomes equal to the flow rate command value α ₀ (t ₂ , t ₄ , t ₆ ).

If the size of C ₁ is set so that it can be stably absorbed against transient disturbances that can normally occur, normal stability reactivity is not affected and changes in the flow rate at startup are suppressed,
A soft start can be performed.

〔The invention's effect〕

According to the present invention described above, a method for controlling a DC shunt field motor for a vehicle, which ensures sufficient stability and quick response as armature current control characteristics during power running, and does not cause current overshoot at startup. Can be provided.

[Brief description of drawings]

FIG. 1 is a control block diagram for calculating the armature chopper conduction ratio used in the control method of the present invention, FIG. 2 is a time chart showing the operation of the change limiter 16 of FIG. 1, and FIG. The figure which shows the main circuit structure of a DC shunt field motor, the 4th.
FIG. 5 is a control block diagram for calculating the armature chopper conduction ratio in the conventional control unit for controlling the main circuit in FIG. 3, and FIG. 5 is a block diagram showing details of the feedback control unit 13 in FIG. 6 is a block diagram showing the details of the damping control unit 14 in FIG. 4, FIG. 7 is a block diagram of the improved control method of FIG. 4, and FIG. 8 is a feedforward control unit 12 in FIG. 3 is a block diagram showing the details of FIG. 3 ... Input filter reactor, 4 ... Input filter capacitor, 5 ... DC shunt field motor, 6 ... Armature,
7 ... Field winding, 8 ... Armature chopper, 10 ... Field chopper, 11 ... Armature current calculation unit, 12 ... Feedforward control unit, 13 ... Feedback control unit, 14 ... Damping Control unit, 15 ... Adder, 16 ... Change limiter.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-58-35436 (JP, A) JP-A-54-155511 (JP, A) JP-A-58-92002 (JP, A) JP-A-49- 93823 (JP, A)

Claims (1)

[Claims] 1. A DC shunt field motor is used as a vehicle main motor, and an armature chopper is provided between the armature and a main power source electrically connected to the armature chopper.
Feed-forward conduction ratio obtained by function calculation from field current, motor speed and armature current command value, feedback conduction ratio obtained by amplifying deviation of armature current, filter capacitor voltage differential and armature In controlling the actual flow rate of the armature chopper with the sum of the damping flow rate obtained from the current differential as the flow rate command value of the armature chopper, the rate of change of the flow rate command value is a predetermined value. When it exceeds, the control method of the direct current shunt field motor for a vehicle, wherein the actual flow rate is converged to the flow rate command value according to the predetermined value.