JPH0687604B2 - Control device for DC shunt field motor for vehicle - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a DC shunt field motor used as a main motor for a railway vehicle, for example, and a chopper for supplying currents to the armature and field winding, respectively. The present invention relates to a control device for a DC shunt field motor for a vehicle, which is controlled by.

[Technical background of the invention and its problems]

FIG. 4 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 winding field motor, 8 is an armature chopper connected in series with the armature 6, and 9 is a flywheel diode connected in parallel with the armature 6. Further, 10 is a field chopper that controls a field current flowing through a field winding 7 of a DC shunt field motor (hereinafter referred to as an electric motor) 5.

In such a structure, when powering, the conduction ratio of the armature chopper 8 is α, and the conduction ratio of the field chopper 10 is
The field current IF is controlled so as to be proportional to the armature current IA at a predetermined ratio.

FIG. 5 shows the conventional flow rate α of the armature chopper 8.
A block diagram for explaining a first example of the control method of
Reference numeral 12 is an armature current command value calculation unit, 13 is a feedback control unit, 14 is a damping control unit, and 15 is an adder. Armature current command value IC calculated by armature current command value calculation unit 12
Is given to a feedback control unit 13 including a subtracter 19 and a first-order lag element 20, as shown in FIG. That is, the subtracter 19 obtains the current deviation ΔI between the armature current command value IC and the armature current IA, and further amplifies the current deviation ΔI by the first-order delay element 20 to obtain the feedback conduction ratio α ₂ . Note that K ₀ is an amplification gain and T ₀ is a delay time constant. The damping control unit 14 in FIG. 5 is for strengthening transient stability and prevents hunting that cannot be suppressed only by the feedback control unit 13.

FIG. 7 shows the details of the damping control unit 14. The differentiator 21 differentiates the armature current IA to obtain the output α ₃₁ , and the differentiator 22 differentiates the filter capacitor voltage EC to obtain the output α ₃₂ . Then, both outputs α ₃₁ and α ₃₂ are subtracted in the subtractor 23 to obtain the damping conduction ratio α ₃ . Then, this damping conduction ratio α ₃ is input to the adder 15 as shown in FIG. 5 and is added to the feedback conduction ratio α ₂ to obtain the armature chopper conduction ratio α. In addition, in FIG. 6 and FIG. 7, K ₂ , K
₃ shows the amplification gain, and S shows the Laplace operator.

Although the armature current IA is controlled to be approximately equal to the armature current command value IC by the above control method, the conventional control method has the following problems.

Responsiveness of the control is mainly dependent on the amplification gain K ₀ and delay time constant T _0, moderation amplification gain K ₀ is large also small delay time constant T ₀ is earlier response. On the other hand, however, stability is a reciprocal relationship, and it is difficult to ensure stability without losing stability and to respond quickly enough to large disturbances such as sudden changes in the overhead line voltage of the vehicle for the following reasons. is there. That is, as shown in FIG. 2, not only the field winding is not inserted in the circuit of the armature chopper 8 of the electric motor 5 but also the main smoothing reactor is removed, so that the impedance of the circuit is equal to that of the armature 6. The impedance is extremely small as compared with a chopper circuit using a DC direct winding motor. Therefore, the armature chopper 8 is required to have an extremely high-speed response to a change in the voltage of the overhead wire, and at the same time, the stability cannot be achieved at the same time.

[Object of the Invention]

The present invention has been made in consideration of the above circumstances,
An object of the invention is to provide a control device for a DC shunt field motor for a vehicle, which has sufficient stability and quick response as an armature current control characteristic during power running.

[Outline of Invention]

To achieve the above object, in the present invention, a feedforward control unit for obtaining a feedforward conduction ratio by a function operation from a filter capacitor voltage, a field current, a motor rotation speed and an armature current command value is added to the conventional one. Then, the added value of the feed-forward conduction rate, the feedback conduction rate, and the damping conduction rate is output as the conduction rate of the armature chopper, and the change limiter determines the amount of change in the added value by the high-value priority circuit. When the amount is exceeded, the change amount of the flow rate of the armature chopper is set as the limited change amount, so that both stability and quick response can be achieved.

Example of Invention

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a control block diagram of FIG. 5 in which a feedforward control unit 16, a change limiter 17 for limiting the amount of change in the flow rate at the time of powering start, and a high value priority circuit 31 are added. Details of the feedforward control unit 16 are shown in FIG. The operation will be described below with reference to FIG. The function generator 24 has the magnetization characteristics of the electric motor as a function,
When the field current IF is input, the field flux K · φ is obtained. Then, the multiplier 25 multiplies the field magnetic flux K · φ by the motor rotation speed VLC to obtain the motor back electromotive force EM. When the armature resistance of the motor is R, the feedforward 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 generator 26 executes this calculation, and outputs the result as the feedforward conduction ratio α ₁ . In this case, since the armature current IA is not used in the process of obtaining the feedforward conduction ratio α ₁ , it is called feedforward control.

Obtaining the feedforward conduction ratio α ₁ in this way means that IC = IA for all overhead line voltages and rotation speeds.
Therefore, even if the filter capacitor voltage EC changes suddenly due to a sudden change in the overhead line voltage, the appropriate conduction ratio will be commanded accordingly, and the armature current IA will be It does not deviate significantly from the slave current command value IC.

If the characteristics of the motor circuit completely match the values used in the calculation, then the feed-forward conduction rate α ₁ thus obtained does not have a feed-forward conduction rate α ₂ , but IC = IA
However, in reality, IC = IA does not always hold due to the deviation of the magnetization characteristics, the temperature change of the armature resistance value R, and the like. Therefore, the feedback control unit 13 is still necessary to correct this, but its role is merely constant current correction, and absorption of steep disturbances such as a sudden change in the overhead line voltage is almost entirely as described above. Since it is handled by 16, the amplification gain K ₀ of the internal first-order lag element 20 does not need to be so large, and the lag time constant T ₀ can be set to a sufficiently large value. That is, it is not necessary to force a quick response at the expense of stability.

However, at start-up, the feedforward conduction ratio α ₁ is output in steps as the armature chopper conduction ratio α, and as described above, it is necessary to correct the feedback conduction ratio α ₂ due to the characteristic deviation. In this case, especially when the feedforward conduction ratio α ₁ alone opens the phase too much, there is a high possibility of causing an overshoot of the current and causing an overcurrent. A change limiter is added which acts as shown in FIG. 3 to limit the amount in proportion to the motor speed so that the amount is small at low speed and large at high speed.

On the other hand, the electric motor speed (speed signal) VLC input to the feedforward control unit 16 is input to one input terminal of the high value priority circuit 31 via the proportional constant 30 of K ₃ , and the other of the high value priority circuit 31 is input. A constant 32, C _2, which defines the absolute value of the time change dα ₀ / dt of α ₀ during normal acceleration is input to the input terminal. The output DAL of the high price priority circuit 31 is input to the change limiter 17. The change limiter 17 determines the conduction ratio of the chopper 8 shown in FIG. 2 from the output α ₀ from the adder 15.

In this way, by adding an algorithm consisting of the proportional constant 30, the constant 32, and the high-value priority circuit 31, the change limiter 17 is large in a high speed region, and the change limiter 17 is small in a low speed region. You can

As a result, it is possible to obtain a control system in which the conduction ratio can quickly rise in the high speed region and the current does not overshoot in the low speed region.

〔The invention's effect〕

According to the present invention described above, the added value of the feedforward conduction ratio (α ₁ ), the feedback conduction ratio (α ₂ ) and the damping conduction ratio (α ₃ ) is output as the conduction ratio of the armature chopper. , When the change amount of the added value exceeds the limit change amount defined by the high-value priority circuit by the change limiter, the change amount of the armature chopper's conduction ratio is used as the limit change amount, so that the current rise according to the pattern Can be raised,
It is possible to provide a control device for a DC shunt field motor for a vehicle, which has sufficient stability and quick response as armature current control characteristics during power running.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control device for controlling the armature chopper conduction ratio according to the present invention, FIG. 2 is a block diagram showing details of a feedforward control unit in FIG. 1, and FIG. 3 is FIG. FIG. 4 is a diagram showing the action on the conduction ratio α when the control device of FIG. 4 is used, FIG. 4 is a diagram showing the main circuit configuration of a DC shunt field motor for railway vehicles, and FIG. 5 is the main circuit of FIG. FIG. 6 is a block diagram showing a conventional device for controlling the flow rate of an armature chopper in FIG. 6, FIG. 6 is a block diagram showing details of a feedback control unit in FIG. 5, and FIG. 7 is a damping control unit in FIG. It is a block diagram showing details. 1 ... Pantograph, 2 ... Wheel, 3 ... Input filter reactor, 4 ... Input filter capacitor, 5 ... DC shunt field motor, 6 ... Armature, 7 ... Field winding, 8
...... Armature chopper, 9 ...... Flywheel diode, 10 ...... Field chopper, 12 ...... Armature current command value calculation unit, 13 ...... Feedback control unit, 14 ...... Damping control unit, 15 ...... Adder , 16 …… Feed forward control block, 17 …… Change limiter, 30 …… Proportional constant, 31 …… High price priority circuit, 32 …… Constant.

Claims (1)

[Claims] 1. A feedforward control unit, a feedback control unit, a damping control unit, a high price priority circuit,
A change limiter, the feedforward control unit, the field current flowing through the field winding of the DC shunt field motor, the motor speed of the DC shunt field motor, the DC shunt field motor Of the preset armature current command value to be supplied to the armature and the terminal voltage of the filter capacitor connected in parallel with the armature, and the field flux determined from the field current and the motor speed. A product, the sum of the product of the armature current command value and the resistance value of the armature, by dividing by the voltage between the terminals, to calculate and output the feedforward conduction ratio, The feedback control unit is for inputting the armature current and the armature current command value and calculating and outputting a feedback conduction ratio, and the damping control unit outputs the inter-terminal voltage and the armature current. Entering Then, the damping conduction ratio is calculated and output by the differential value of the terminal voltage and the differential value of the armature current, and the high value priority circuit is a change amount determined in proportion to the motor speed. And a predetermined change amount set in advance is input, and a larger one of the change amount determined in proportion to the electric motor speed and the predetermined change amount is output as the limit change amount, and the change limiter is the A feedforward conduction rate, an addition value of the feedback conduction rate and the damping conduction rate, and the limiting change amount are input, and the addition value is output as a conduction rate of an armature chopper, A control device for a DC shunt field motor for a vehicle, wherein when the change amount of the added value exceeds the limit change amount, the change amount of the conduction ratio of the armature chopper is set as the limit change amount.