JP2549166B2 - Electric car control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric vehicle controller that drives an induction motor for propulsion of an electric vehicle using a variable voltage variable frequency inverter, and in particular, it has a relatively large size. It has acceleration / deceleration characteristics
The present invention relates to a control device for a variable voltage variable frequency inverter suitable for an electric vehicle that is prone to slip.

[Prior Art] A train for short-distance transportation, which has a relatively short stop section distance, requires relatively large acceleration / deceleration characteristics to improve transportation efficiency. As a result, idling / sliding It is easy to occur.

However, in the event of such idling / sliding,
Since the adhesive force between the wheel and the rail is less than the driving torque of the wheel by the electric motor for propulsion, if it is left as it is, it will shift to large slip and large gliding, and the predetermined acceleration and deceleration necessary for the vehicle will be obtained. Not only that, but also the riding comfort deteriorates, and when it is unduly high, it may even damage the drive system and wheels.

Therefore, in such a vehicle, it is common to apply a so-called automatic readhesion control system, which conventionally detects idling / sliding and performs torque control to control so that readhesion can be quickly obtained. At this time, in the conventional inverter-controlled electric vehicle, for example, "207 series commuter type DC train (1),
(2) ”As described in“ Science of Electric Vehicles ”, February / March 1987, the time variation d fr / dt of the motor rotation frequency fr is constantly detected, and this time variation is detected. When the amount exceeds a predetermined value, it is considered that slipping / sliding has occurred, a slipping / sliding detection signal is generated, and the induction motor for propulsion is torque-controlled to re-adhere.

By the way, as is well known, the frequency-torque characteristic of an induction motor used as a main motor (propulsion electric motor) in such an electric vehicle is as shown in FIG. Sliding frequency for both child current and torque
It depends on fs, and if this slip frequency fs is made smaller, both will decrease.

Therefore, a re-adhesion method is widely used in which the characteristics of the induction motor are used and the slip frequency fs is quickly narrowed down accordingly when slipping or sliding is detected as described above. That is, as is clear from FIG. 2, if the slip frequency fs is reduced, the armature current of the main motor is reduced accordingly, and as a result, the torque is reduced, and idling / sliding is suppressed. This leads to re-adhesion. Then, after the re-adhesion is obtained in this way, thereafter, the slip frequency fs that has been narrowed down is slowly returned at a predetermined constant rate to allow the slip / slip to resume.
I try not to cause gliding.

On the other hand, in addition to the above method, a method of fixing the frequency when idling / sliding occurs is also disclosed in, for example, Japanese Patent Laid-Open No.
It is proposed by the publication such as −136003.

[Problems to be Solved by the Invention] In the above-mentioned prior art, the setting of the slip frequency, which is necessary for suppressing slipping / sliding and obtaining appropriate re-adhesion, is not considered, and always good re-adhesion is obtained. There was a problem that it was difficult to do.

That is, in the above-mentioned conventional technique, for example, when idling occurs during power running, the slip frequency is narrowed down as described above in response to the idling, but at this time, the electric motor causing idling and rapidly increasing. When the slip frequency fs is sharply reduced corresponding to the rotation frequency fr, the torque due to the inertia of the main motor overcomes the decreasing torque at this time, and as shown in FIG. There is a possibility that the value of will be larger than the value of the inverter frequency f inv. That is, at this time, the state during power running suddenly changes to the state of regenerative braking, which is extremely dangerous.

On the other hand, in order to eliminate such a fear, when idling occurs, if the values of the fluctuating frequency and the slip frequency fs are decreased, the torque decrease becomes insufficient, and as shown in FIG. , Idling is increasing more and more, and eventually Idling.

From the above, even if the increase rate of the motor rotation frequency fr is maximum, it does not become larger than the inverter frequency finv, and in order to promptly reduce the torque at least, the slip frequency fs It is necessary to always select the narrowing rate to the optimum value.

However, the work of selecting this optimum value must be considered including the conditions of the vehicle, the route, and the climate, and is a very complicated work, which requires a great deal of labor.

On the other hand, in the conventional technique of fixing the above frequency,
No particular consideration was given to control after re-adhesion,
Again, there was the problem that slipping and sliding tended to occur.

It is an object of the present invention to provide an electric vehicle control device which solves the above problems and is capable of performing smooth, convenient and highly reliable slip / sliding readhesion control.

[Means for Solving the Problem] The purpose is to store the inverter frequency f inv at the time when idling / sliding is detected, and after this time, keep the inverter frequency f inv constant, and then The inv is increased during power running and is decreased during regenerative braking until the current detection value of the main motor matches the current command value for the motor, and then returns to normal control. Will be achieved.

[Operation] In an inverter-controlled electric vehicle, f inv = f during power running
The inverter frequency f inv commensurate with the electric motor rotation frequency fr at that time is calculated by the calculation formula of r + fs and f inv = fr −fs at the time of regenerative braking to control the electric vehicle. Therefore, when the slip frequency fs is changing during power running, regenerative braking, slipping, etc., the value of the inverter frequency f inv is changing in any case.

Therefore, if the inverter frequency f inv is fixed during idling / sliding, the motor rotation frequency fr approaches the value of the inverter frequency f inv as shown in Fig. 2, and even if idling / sliding occurs Due to the original characteristics of the electric motor, it naturally leads to a decrease in torque, leading to readhesion.

In other words, the inverter frequency f in
Since v is fixed, the motor speed f
Since the value of r increases during power running idling and decreases during sliding of the regenerative brake, the motor current automatically decreases and the torque decreases, so that readhesion can be easily obtained.

However, even at this time, if the normal control is restored, the vehicle will shift to the idling / sliding state again.

Because there is no guarantee that the rotation speed of the main motor at this time corresponds to the inverter frequency f inv determined by the current command value given at this time, and therefore the rotation of the main motor is This is because there is an extremely high probability that the control will shift to the inverter frequency f inv that does not correspond to any speed and cause a sudden change in torque.

However, in the present invention, the inverter frequency f inv at the time when idling / sliding is detected is stored, and after this time, the inverter frequency f inv is kept constant, and then this inverter frequency f inv is increased during powering. Therefore, the regenerative braking is reduced so that the current detection value of the main motor matches the current command value for the motor, and at the same time, the normal control is resumed. There is no possibility of shifting to the idling / sliding state again, and it is possible to smoothly return to normal control as it is in the adhesive state.

[Embodiment] Hereinafter, an electric person control device according to the present invention will be described in detail with reference to an illustrated embodiment.

FIG. 5 shows an example of the electric vehicle control system to which the embodiment of the present invention is applied.
And received via low-pass filter 23, voltage E _S , current
The DC power of I _D is input to the inverter 24, which
Three-phase AC power with a frequency f _o is output at V _O , the drive control of the induction motor 25 for propulsion of the electric vehicle is performed, and the electric vehicle is driven.

The inverter 24 operates by the PWM (pulse width modulation) method,
The input that determines the output voltage V _O is the modulation factor γ, and the output frequency f _o is given by the inverter frequency f inv.At this time, the control of the induction motor 25 _keeps the ratio of the voltage V _O and the frequency f _o approximately constant. The modulation rate setting unit 30
The modulation factor γ is generated based on the DC input voltage E _of captured by the voltage detector 29 and the inverter frequency finv.

On the other hand, the inverter frequency f inv is equal to the rotation frequency detector 2
Based on the rotation frequency fr representing the rotation speed of the induction motor 25 and the slip frequency fs output from the slip frequency setting unit 27 from the current command value I _MP that determines the torque of the motor, which is taken in in (6), the form of (finv = fr + fs) is obtained. Is given from the inverter frequency setting unit 28. At this time, the subtractor 32 calculates the actual current I _MT detected by the current detector 31 and the current command value I _MP.
The feedback control system is formed by contacting with each other.

The readhesion control unit 100 inputs the inverter frequency f inv output from the inverter frequency setting unit 28, and normally outputs it as it is, but performs predetermined processing only when the electric vehicle slips or glides, and inputs it. Inverter frequency
An output different from f inv is generated, and the details thereof will be described below with reference to FIG.

In the embodiment of FIG. 1, 1, 4, and 7 are SR flip-flops, 2 is a normal mode / idling / sliding mode switching section, 3
Is idle / sliding mode-re-adhesion mode switching unit, 5 is latch, 6 is buffer, 8 is αt pattern generating unit, 9 and 10 are OR gates, 11 and 14 are comparators, 12 is rotation frequency switching unit, 13 is constant generation The parts 15 and 16 are adders.

 Next, the operation of this embodiment will be described.

Normally, since the SR flip-flop 1 is reset, the normal mode idling / sliding mode switching unit 2 is switched to the normal mode, and the inverter frequency f inv is transmitted to the inverter 24 as it is.

However, if it is assumed that idling / sliding is detected by the detection means (not shown) at the time t _o in FIG. 6 (during power running) or FIG. 7 (during braking), the SR flip-flops 1 and 4 are thus detected. A signal is provided to the set input of. It should be noted that the detection of the slipping / sliding may be performed by any known method, for example, detection may be performed when the rate of change of the actual rotation frequency fr exceeds a predetermined value.

In this way, when the slip / sliding detection signal is input, the SR flip-flop 1 is set, and as a result, the normal mode / slip / sliding mode switching unit 2 switches from the normal mode to the slip / sliding mode, and the inverter frequency is changed.
The output operation of f inv is idling / sliding mode. At the same time, the SR flip-flop 4 is also set, which allows the inverter frequency f immediately before switching to the idling / sliding mode.
The value of inv is fetched from the buffer 6 into the latch 5 and stored. Then, the fixed value stored in the latch 5 and the idling / sliding mode / re-adhesion mode switching unit 3 and idling /
As shown in FIG. 6 by being output through the normal mode / idling / sliding mode switching unit 2 which has switched to the sliding mode side,
Alternatively, as shown in FIG. 7, the inverter frequency f inv as the output is fixed to the value immediately before the time t _o , and the idling / sliding is quickly suppressed.

On the other hand, in parallel with this, the value of the fixed inverter frequency f inv is also applied to the + input of the comparator 11,
As a result, at the time of power running, the maximum value f of the electric motor rotation frequencies of the plurality of electric motors that are simultaneously controlled by the inverter via the rotation frequency switching unit 12 switched to the P side.
_rMAX is taken in, and in the adder 16, the relationship between the inverter frequency f inv and the motor rotation frequency fr is not reversed, that is, to the regenerative braking state during power running, to the power running state during regenerative braking. To prevent change,
A value generated by adding a predetermined constant value fk set in advance to the setting generation unit 13 is compared, and at the time of regenerative braking, the minimum value f _{rMIN of the} rotation frequency of a plurality of motors which are being controlled simultaneously.
Compared with the value obtained by subtracting a constant value fk from. And
With the OR gate 9, the condition when f invfr _MAX + fk is reached during power running and the condition f invfr _MIN −fk is reached during regenerative braking, and the temporal change rate of the motor rotation frequency fr is below a certain value ε. By taking an OR logic with the condition and setting the SR flip-flop 7, the idling / sliding mode / re-adhesion mode switching unit 3 is switched to the re-adhesion mode. At the same time, the SR flip-flop 4 is reset and the enable signal of the latch 5 is set to "L". Further, at the same time, the αt pattern generator 8 is started, and the value of the inverter frequency f inv fixed to the latch 5 is added by the adder 15 to the product αt of the constant α and the time t during power running, During regenerative braking, a process of subtracting the product αt is performed, thereby gradually returning to the reference speed, that is, the inverter frequency f inv given from the inverter frequency setting unit 28.

Thus, by the output from the αt pattern generation unit 8,
The value of the signal f inv output to the inverter 24 returns to the reference speed, that is, the signal f inv supplied from the inverter frequency setting unit 28, and the slip frequency f in the normal state is returned.
When the value of s is generated, the main motor current command value I _{MP held} as a pattern and the actual main motor current 0.5 Hz
When the value I _MT coincides with the value I _MT , the SR flip-flop 1 is reset by the output of the comparator 14, thereby returning the normal mode / idle / regenerative mode switching unit 2 to the normal mode. At the same time, the SR flip-flop 7 is also reset, whereby the .alpha.t pattern generator 8 is reset to return the value of the time t to zero, and the idle / sliding mode-re-adhesion mode switching unit 3 is also returned to the idle / sliding side.

In the re-adhesion mode described above, while the value of the fixed inverter frequency f inv is being added or subtracted from αt, for example, the idling / sliding is performed again at time t ₁ in FIG. If it occurs, the slip / slide detection signal resets SR flip-flop 4. As a result, the value of the inverter frequency finv that is returning to the reference speed is newly stored and fixed in the latch 5, and at the same time, the SR flip-flop 7 is reset and the idling / sliding mode / re-adhesion mode switching unit 3 is reset. The adhesive mode is switched to the idling / sliding mode, and the αt pattern generating section 8 is reset. Therefore, the above operation is repeated thereafter.

Of the above operations, the operation during power running shown in FIG. 6 is represented by a time chart as shown in FIG. In FIG. 8, A to G represent the levels in the coded parts given in FIG. The broken line indicates the inverter frequency setting section
28 represents the inverter frequency given by 28, and the solid line represents the inverter frequency supplied to the inverter 24.

According to the present embodiment, since the inverter frequency f inv is fixed to a constant value during idling / sliding, the characteristic peculiar to the induction motor is utilized, and a natural reduction in the torque of the idling / sliding shaft is provided. Re-adhesion is surely obtained. Then, after that, this inverter frequency f inv is increased during power running and is reduced during regenerative braking, and when the detected current value of the main motor matches the current command value for the electric motor, normal control is restored. Because
There is no risk of slipping / sliding again,
There is an effect that it is possible to smoothly return to normal control as it is in the adhesive state, and thus to significantly improve the readhesion performance.

Further, according to this embodiment, even when the idling / sliding is repeated, the re-adhesion control can be sufficiently dealt with,
There is an effect that re-adhesion is always given.

[Effects of the Invention] According to the present invention, since the inverter frequency is fixed to a constant value during idling / sliding, the characteristic peculiar to the induction motor is utilized, and the torque of the idling / sliding shaft is naturally reduced. , Re-adhesion is surely obtained, and then this inverter frequency is increased during power running and decreased during regenerative braking, and normal control is performed when the detected current value of the main motor matches the current command value for the electric motor. Since there is no risk of shifting to the idling / sliding state again, it is possible to smoothly return to normal control as it is in the adhesive state, so that the re-adhesive performance can be improved. There is an effect that it can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing details of a readhesion control section in an embodiment of an electric vehicle control device according to the present invention, FIG. 2 is a characteristic diagram of an induction motor, and FIGS. 3 and 4 are operation explanations in the prior art. FIG. 5 is a block diagram showing an electric vehicle control system to which an embodiment of the present invention is applied, FIGS. 6 and 7 are operational characteristic diagrams of an embodiment of the present invention, and FIG. 8 is an embodiment of the present invention. 3 is a time chart showing the operation of the embodiment. 1,4,7 …… SR flip-flop, 2 …… Normal mode-slip / sliding mode switch, 3 …… Slip / sliding mode-re-adhesion mode switch, 5 …… Latch, 6 …… buffer, 8…
… Αt pattern generator, 9, 10… OR gate, 11, 14…
… Comparator, 12 …… Rotation frequency switching section, 13 …… Constant generation section, 15,16 …… Adder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Suzuki 4087 Michihatsu, Jinmachicho, Tsuchiura, Ibaraki Prefecture Tsuchiura Plant, Hitachi Techno Engineering Co., Ltd. Company Mito Factory Mito Plant (72) Inventor Kenichi Junga 4-46-5-406 Ikebukuro Honcho, Toshima-ku, Tokyo (56) Reference JP-A-59-136003 (JP, A) JP-A-58-130703 (JP, A) JP 59-201608 (JP, A)

Claims (1)

(57) [Claims] 1. A control device for an electric vehicle, comprising a variable voltage variable frequency inverter, and driving a propulsion induction motor with a variable voltage variable frequency by the output of the variable voltage variable frequency inverter. Switching control (2) for switching to the normal mode when the current detection value I _MT of the induction motor matches the current command value I _MP for the motor, and a slipping / sliding mode. and latch means (5) for storing captures the output frequency f _inv of the variable voltage variable frequency inverter when the detection signal is generated, the frequency f _inv which is stored in the latch means (5), the motor rotation frequency the comparator compares the value obtained by adding a predetermined value f _k predetermined for f _r (f _r + f _k), and comparing means towards the frequency f _inv is for generating an output when a large (11), compare The switching means is controlled to switch to the readhesion mode by the output of the means (11), and is controlled to switch to the idling / sliding mode when the current detection value I _MT of the induction motor matches the current command value I _MP to the motor. 3) is provided, and the switching means (2) supplies the output of the inverter frequency setting section to the variable voltage variable frequency inverter when switched to the normal mode, and the switching means when switched to the idling / sliding mode. The output of (3) is configured to be supplied to the variable voltage variable frequency inverter, and the switching means (3) has a frequency f _inv stored in the latch means (5) when switched to the idling / sliding mode. Is supplied to the switching means (2), and when the readhesion mode is switched to, the output of the adding means (15) is supplied to the switching means (2). Electric vehicle control apparatus according to.