JPH03107306A - Readhesion control system for inverter type electric vehicle - 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] [Industrial Application Field] The present invention promptly suppresses the slip when it occurs, and makes it possible to utilize the adhesive force between the axle and the rail as effectively as possible as a traction force. This article relates to a readhesion control method in an inverter type electric vehicle.

[Conventional technology]

As a readhesion control system for inverter type electric vehicles, the one shown in Fig. 2 is in practical use. In Fig. 2, 1 is a current command generation device, and 3 is a current control unit, which performs an appropriate transfer function to stably control the effective value of the motor current to a value equivalent to the current command and a correction calculation to convert the current value into a slip frequency. have 6 is PW
The M control unit calculates the modulation rate and number of pulses for pulse width modulation based on the input inverter frequency, and outputs a gate signal for the GTO thyristor constituting the inverter 7. The inverter 7 has the firing angle of the GT○ thyristor controlled by the gate signal, outputs a three-phase variable voltage and a variable frequency voltage, and drives a three-phase induction motor 9 by the output. 8 detects the current of the three-phase induction motor 9 and calculates and outputs its effective value.

Reference numeral 11 denotes a train speed detection device, which converts the train speed into a value equivalent to the rotational frequency of the induction motor and outputs it. The train speed can be determined by using the output of a pulse generator provided on the wheel axle, or by using the lowest output frequency of the pulse generator provided on each driving wheel axle. 10 is a rotational frequency detection device for the induction motor 9, which calculates and outputs the rotational frequency from the output of a pulse generator attached to the end of the motor shaft. Reference numeral 13 denotes a readhesion control signal generation unit, which generates a readhesion control signal to stop slipping as shown in the figure when the difference between the motor rotational frequency and the rotational frequency equivalent to the train speed, that is, the rotational frequency difference equivalent to the slipping speed exceeds Δ. Δfs is generated. Reference numerals 2, 5, and 12 are adder units, each of which performs the addition shown in the figure. Reference numeral 14 is a code conversion unit. Reference numeral 4 denotes a switching section, which inputs the output of the current control section 3 to the addition section 5 when the vehicle is stuck, and inputs the re-adhesion control signal Δfs to the addition section 5 when the vehicle is idling. Discrimination between slipping and adhesion is made by the presence/absence of the re-adhesion control signal Δfs.
o is a constant value of the slip frequency.

With the above configuration, when sticky, constant current control is performed so that the effective value of the motor current remains constant equivalent to the current command value, and when slipping occurs and Δfs occurs, this constant current control is turned off and readhesion control is performed. This is to reduce the slip frequency, reduce the motor torque, and re-adhesion. in this way.

The reason why constant current control is turned off when the motor is idling is because constant current control tries to keep the motor torque constant, which acts to encourage idling and prevents re-adhesion. This is because the entire control system tends to become unstable if the slip frequency is reduced by the readhesion control signal. but.

In this method, the constant current control that promotes slipping operates until the rotational frequency difference equivalent to the slipping speed reaches Δ. Therefore, it is necessary to increase the readhesion control signal Δfs in order to make it stick again, and the adhesion force is increased. Fine control of readhesion for maximum effective use becomes difficult. In addition, when driving a complex number of parallel-connected induction motors with one inverter, the torque of the motor driving the sticky shaft increases while constant current control is working, causing the shaft to idle. There is also the problem that this can lead to idling of all axes.

In addition, a control method as shown in Figure 3 has been proposed (Proceedings of the National Conference of the Institute of Electrical Engineers of Japan, 1989, !!lI, Volume 895).
, only the parts different from FIG. 2 will be explained below.

In the third time, 15 is a proportional element to which a constant value C is multiplied.

In other words, instead of detecting slippage and turning off the constant current control and using the readhesion control signal to reduce the slipping frequency and readhesion as shown in Figure 2, a subloop is added to the constant current control system to control the rotational frequency equivalent to the slippage speed. A signal proportional to the difference is negatively fed back to the input section of the current control section. In this way, there is no dead zone Δ as shown in FIG. 2, and if there is even a slight difference between the circumferential speed of the driving wheels and the train speed, the current decreases and slipping can be suppressed with high sensitivity. However, as in this example, if a dead band is not provided in the rotation frequency difference feedback system corresponding to the idling speed, the motor torque may fluctuate due to the minute idling speed when driving on a curved road, and the relative slipping speed between the driving wheels and the rail may increase. Then, even at a very small idling speed in the so-called veri region where the frictional force between the driving wheels and the rail increases, the motor torque decreases, making it impossible to generate sufficient torque. This is particularly a problem when using a low-loss induction motor with a small slip ratio. In addition, it is often necessary to provide a delay element in the current control section 3 to stabilize the constant current control system, but in such cases, the input of the current control section 3 as shown in FIG. If the rotational frequency difference corresponding to the idling speed is negatively fed back to the side, there is a problem that the response speed is slow and high-performance readhesion control cannot be performed.

[Problem to be solved by the invention]

An object of the present invention is to provide a readhesion control system for an inverter type electric vehicle that improves the problems of the conventional system as described above.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a first dead zone Δ
1 and a second readhesion control signal generation section having a second dead zone Δ2. The output signal of the second re-adhesion control signal generating section is self-feedback to the output side of the current control section 3 (second feedback system). be.

[Effect]

Due to the above-mentioned first dead zone, it is possible to prevent the minute slip speed during curve travel and in the false slip region from being fed back, and one of the problems of the embodiment of FIG. 3 is solved.

Furthermore, by providing the second feedback system, the response speed of readhesion control can be increased even when the current control section has a large delay, and other problems of the embodiment shown in FIG. 3 can be solved.

On the other hand, a first feedback system is provided in addition to the second feedback system, and the first
By selecting an appropriate value for the dead zone, in the embodiment shown in FIG. 2, it is possible to prevent the constant current control system from promoting idling until the idling speed reaches a value equivalent to the dead zone Δ. Moreover, by providing the first feedback system, it is possible to prevent the system from becoming unstable even if the switching section 4 of the embodiment shown in FIG. 2 is omitted.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
In the figure, 16 is a first readhesion control signal generation unit, which has a dead zone Δ1, and when the input rotational frequency difference corresponding to the spatial distance is less than Δ1, the output is zero, and when it exceeds Δ1, the output is as shown in the figure. will occur. Reference numeral 16' denotes a second readhesion control signal generating section, which has a dead zone Δ2, and produces an output of zero when the input rotational frequency difference corresponding to the idling speed is less than Δ2, and produces an output as shown when it exceeds Δ2. As shown in the figure, the first feedback system provides negative feedback to the input control side of the current control section 3, and the second feedback system provides negative feedback to the output side of the current control section 3. The first dead zone Δ1 is normally selected to be smaller than Δ2 to prevent the constant current control system from promoting idling until the idling speed reaches the dead zone Δ2. Dead zone Δ1. By selecting appropriate values for the gains g1pg2 in addition to Δ2, it is possible to achieve good re-adhesion control without the problems of the conventional array.

The above description has been about readhesion control for slipping when the vehicle is traveling, but the same method can be applied to readhesion control for skidding during regeneration control. During regenerative braking, the induction motor 9
acts as a generator, and inverter 7 acts as a converter to regenerate electric power to the overhead wire side.

As for the readhesion control system, since skidding is a phenomenon in which the peripheral speed of the driving wheels becomes smaller than the train speed, the only change is that the sliding speed becomes the train speed - the peripheral speed of the driving shaft.

Further, in the embodiment shown in FIG. 3, the readhesion control signal is assumed to change linearly with respect to the input slip speed, but the present invention is not limited to this, and for example, a differential value of the slip speed may also be used. be able to.

In addition, any change caused by idling, such as the differential value of the driving wheel shaft speed, rather than the idling speed, can be used.

〔Effect of the invention〕

According to the present invention, it is possible to provide an inverter-type electric train or an inverter-type locomotive with good adhesion performance, and in the case of electric trains, - the number of motive cars in a train formation is reduced, the total weight of the train formation is reduced, and energy is saved. can be achieved, increasing running acceleration and shortening the arrival time. Furthermore, in the case of locomotives, it has the advantage of being able to tow a large amount of load with a lighter locomotive.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the readhesion control method of the present invention, FIG. 2 is a block diagram of a conventional readhesion control method, and FIG. 3 is a block diagram of another example of the conventional readhesion control method. It is a block diagram. DESCRIPTION OF SYMBOLS 1...Current command generator, 2,2.12...Addition part, 3...Current control part, 4...Switching part, 6...P
WM control unit, 7... Inverter, 8... Effective current value detection device, 9... Induction motor, 10... Motor rotation frequency detection device, 11... Train speed detection device, 13.
16°16'...Re-adhesion control signal generator, 15...
・Proportionality required Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A first re-adhesion control signal generating section having a first dead zone Δ1 and a second re-adhesion control signal generating section having a second dead zone Δ2 are provided; The output signal of the second readhesion control signal generation section is fed back to the input side of the current control section 3, and the output signal of the second readhesion control signal generation section is fed back to the output side of the current control section 3. Re-adhesion control method for inverter electric vehicles. 2. The inverter-type electric vehicle according to item 1, wherein the readhesion control signal generating section receives an input as a signal proportional to the idling speed, and generates an output signal that increases with the input when the input exceeds a dead band value. Re-adhesion control method.