JPH01117605A - electric car control device - 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 relates to an improvement of a control device for an induction motor type electric vehicle,
In particular, the present invention relates to a control device for an electric vehicle that operates at a constant speed.

[Conventional technology]

Regarding constant speed operation of an induction motor type electric vehicle, firstly, Japanese Patent Application Laid-Open No. 124/18/1987 discloses an electric vehicle intended for road driving. This control device is
This method determines the slip frequency using a function generator that changes linearly in proportion to the deviation between the commanded speed and the induction motor speed, and has both positive and negative limit values. The rest of the control system is the same as a general one, and is configured to control the output voltage of the inverter in accordance with a frequency command given to the inverter.

Further, in Japanese Patent Application Laid-Open No. 54-22607, in an electric railway car, for example, the first notch is 10 km/h.

30km/h at the second notch, 60km/h at the third notch
, 1100 K/h for the fourth notch, and so on, in which a speed command is determined corresponding to each notch command to control the output frequency of the inverter.

Furthermore, the magazine “Electric Car Science J 1985 Vol.
38 No. 2 Pages 15 to 24, especially No. 20
The page discloses that constant speed control is performed by narrowing down the slip frequency when the speed of an electric vehicle approaches a speed limit.

In addition, the specification and drawings of Japanese Patent Application No. 60-220124 state that by providing an operating means for generating a constant speed command, the vehicle can be driven at any speed while maintaining the same operability as a conventional electric vehicle. A device is shown that allows constant speed operation of the vehicle.

By the way, generally during constant speed driving, not only power running but also regenerative braking may be performed. Normally, during regenerative braking, the motor current is constantly monitored, and if it becomes smaller than a certain value, the main circuit is opened and the regenerative braking operation is turned off. This is because if the regenerative braking effect becomes smaller than a certain value, a sufficient regenerative braking action cannot be expected, so no extra operation is performed in such a region.

[Problem that the invention seeks to solve]

Generally, during constant speed operation, the deviation from the target value is corrected by repeating power running and braking near the target speed.
The required torque is small, and naturally the motor current is also small. Therefore, if the brake mode is entered during constant speed operation, the main circuit will be opened by the control function based on the motor current detection described above, and the brake will not be applied.
Constant velocity may be lost.

Although there is no mention of these problems in the above four cases, it is common to have a control function based on motor current detection during braking, and therefore, a constant speed operation function is performed as described above. It has the potential to disappear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for an induction motor type electric vehicle that is capable of reliable constant speed control at any speed while maintaining driving operability similar to that of conventional electric vehicles.

[Means for solving problems]

In order to achieve this object, the present invention provides a power converter that outputs a variable voltage/variable frequency voltage, a driving induction motor that is powered by the output of the power converter, and a detection speed corresponding to the speed of the vehicle. A speed detection means for obtaining a signal, a power running command,
an operating means for generating a brake command and a constant speed command; a means for generating a first slip frequency signal based on the powering command and the brake command; and a second slip frequency signal based on the constant speed command.
means for generating a slip frequency signal, and controlling the output frequency and voltage of the power converter according to the first or second slip frequency signal and the detected speed signal to operate the induction motor in power running and regenerative braking. An electric vehicle control device comprising: a power converter control means for detecting the motor current; and a main circuit opening means for detecting the motor current and opening the main circuit when the motor current becomes equal to or less than a predetermined value during regenerative braking operation, The present invention is characterized in that a disabling means is provided for disabling the main circuit opening function of the main circuit opening means when the constant speed command is generated.

[Effect]

During regenerative braking in constant speed driving control based on a constant speed command, regenerative braking is continued even if the vehicle speed approaches the target value and the regenerative braking action decreases, so reliable constant speed control is possible.

〔Example〕

Hereinafter, preferred embodiments of the present invention illustrated in the drawings will be described in detail.

In FIG. 1, the DC current collected from the DC overhead contact line 1 is applied to the inverter 2 via the current breaker 26, and is converted by the inverter 2 into AC with variable voltage and variable frequency to drive induction motors 31 and 32. Powered by

The induction motor 31 is used to obtain the vehicle speed equivalent signal f.
．． A pulse generator 41.42 connected to 32 is provided;
Convert the number N of those output pulses into the signal [rN/
An f converter 5 is provided.

The main controller 6 includes a brake notch 6a, a cutting notch 6b,
A constant speed notch 6e is provided outside the power running first notch 6c and second notch 6d. At the first or second notch of power running,
A constant slip frequency pattern f5,1 is generated by the slip frequency (f,) pattern generator 7, and the motor current (
IM) Motor current command IMP by pattern generator 8
Generate I. The changeover switches 9 and 10 are in the state shown in the figure in the power running notch. Therefore, the slip frequency command f
sP+ directly becomes one adder 110. On the other hand, the motor current I4 is detected by the current detector 12,
Comparator 13 compares it with motor current command IMP. This comparator 13 detects the slip frequency command f8. A correction signal is generated for correcting f and is applied to the other input of the adder 11. The output of this adder 11 becomes a slip frequency signal f, which is added (power running) or subtracted (regeneration) to the aforementioned vehicle speed equivalent (motor rotor speed) signal f, , by an adder 14.
be done. The output fINv of this adder 14 is input to the PWM modulation section 15 as an inverter frequency command.

The inverter frequency command flNv is further set at a control voltage VCI such that the ratio of voltage V to frequency r (V/f) is constant.
The signal is input to a V/f converter 16 which generates the voltage.

At the first or second power running notch, the notch stop voltage generator 17 generates a notch stop voltage VCZ set for each notch as shown in the figure.

The low priority circuit 18 receives the control voltage VCI and the notching voltage V mentioned above. Select the low level of 2 and set the inverter output voltage command■. The signal is output to the PWM modulator 15 as a signal.

The PWM modulator 15 receives these inverter frequency commands f
lNV and inverter output voltage command■.

The operating frequency and modulation degree of the inverter 2 are controlled accordingly.

Well, 1. At the second power running notch, the pattern generator 8
Although it is a constant value, at the first power running notch, as the inverter frequency command f INV increases, a restriction is applied as shown in the figure. The reason for this is that the slip frequency f remains large at the first power running notch, and only the control voltage Vc is reduced to the notch stop voltage VCZ.
If it were to be suppressed, the next time the second notch is applied, the voltage restriction will be lifted and a large torque will suddenly be generated.

Therefore, the slip frequency signal f is also narrowed down by the f3 correction signal from the current control system.

In addition, in this embodiment, there are only two power running notches,
At the second notch, a voltage corresponding to the maximum output voltage of the inverter can be output, as shown in the notch stop voltage generator 17 as V Cn+mx, and there is virtually no voltage restriction. This is because it is considered that there is no need for a greater number of power running notches since the constant speed operation command described below is also used.

Note that among the control systems described above, instead of the control system using the control voltage V with V/f=constant, the following control system may be used. That is, the control voltage ■ is input to the low priority circuit 18 in accordance with the output of the comparator amplifier 13 that amplifies the deviation between the current command INF and the current feedback value ■. The goal is to obtain . This is because under the frequency control system of fINV = fr ±f, if ■/f = constant, r and ζ will be constant, while if 1 = constant, V/f# will be constant. , it is also possible to select any of them as a control system.

On the other hand, during regenerative braking, the motor current detection circuit 22 operates, and when the motor current becomes smaller than a certain constant value, the current interrupter 26 is opened. Since it takes time for the motor current to increase to a certain value or more when the brake is applied, this on-delay means is used to prevent the motor current detection circuit 22 from performing control operations during this time.

The characteristics of the motor current detection circuit 22 are shown in FIG. 2, and providing hysteresis in this manner enables stable detection and control.

The above-mentioned control during power running or regenerative braking is similar to the well-known 3g 2JJ and motor electric vehicle control, as shown by the notch curve on page 20 of the aforementioned Science of Electric Vehicles. executed.

Now, assume that the main controller 6 is put into the constant speed operation notch 6e. Then, first, the signal on the constant speed command line 19 switches the changeover switches 9 and 10 to open and close positions opposite to those shown. On the other hand, when a constant speed command is given to the target speed setter 20, the target speed setter 20 latches a signal f corresponding to the vehicle speed at that time (motor rotational speed), and uses this as the subsequent speed command signal f, shall be. In addition, when a constant speed command is given, if there is a signal that stores that the immediately preceding notch is the second power running notch, (latched vehicle speed equivalent signal fr) + (5 Km/h equivalent signal) = speed command signal f.

The speed comparison amplifier 21 receives the speed command signal f.

and a vehicle speed equivalent signal f, and a second slip frequency signal f3,2 as shown in FIG. 3 is determined for the deviation Δf.
and generates a second current command signal IMF□. These second slip frequency signals f3, 2 and current command signal IMPil are converted into new slip frequency command rsp and motor current command I via changeover switches 9 and 10, respectively.
It is given as MP.

Therefore, the vehicle speed is near the desired speed (at the second notch)
If the constant speed notch is engaged when the vehicle accelerates to 1, the vehicle will smoothly rise to a speed 5 Km/h higher than that speed, and then drive at a constant speed while powering or using regenerative braking to maintain that speed. do.

Further, when a constant speed notch is commanded from the coasting (cutting notch) or the first powering notch, the vehicle speed equivalent signal f, , at that time is used as the subsequent speed command r.

and perform the same constant speed operation.

Here, as the characteristics of the comparison amplifier 21 are illustrated in FIG. 3, by providing a slight dead zone (corresponding to ±0.8 Km/h), smooth switching between power running and regenerative braking is performed. Further, by setting the characteristic to be saturated at ±5 Km/h5K, a constant speed characteristic with a constant speed command of ±5 Km/h5K can be obtained.

During constant speed operation, the power running/brake discriminator 23 discriminates the signal from the comparator amplifier 21 and outputs a brake mode signal, so that the control system enters the brake mode and the same control as normal regenerative braking is executed. Ru.

By the way, during constant speed operation, a signal from the constant speed command line 19 switches the changeover switch 25 to an open/close position opposite to that shown in the drawing. In this way, the control function by the motor current detection circuit 22 can be disabled during the constant speed operation, and there is no fear that the main circuit will be opened even if the motor current becomes small, resulting in stable constant speed operation control. It has the tremendous effect of being able to continue.

On the actual flow side, the main controller 6 is provided with a notch for generating a constant speed command and a brake command, but a means separate from the main controller 6 may be installed. Further, although the number of power running notches is set to only two stages, it is also possible to set the number to three or more stages. Furthermore, instead of determining the speed command for constant speed operation according to a signal equivalent to the actual vehicle speed, constant speed operation can be performed by a method such as specifying a speed command for constant speed operation using a keyboard, etc., and then commanding constant speed operation. Modifications such as shifting to operation are also possible.

Furthermore, many of the control system components can be replaced by functions obtained by data processing by a microcomputer.

〔Effect of the invention〕

According to the present invention, it is possible to reliably perform constant speed operation control at any speed while retaining the feeling of notch handling of a conventional electric railway vehicle.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control device for an induction motor type electric vehicle according to the present invention, FIG. 2 is a characteristic diagram of a motor current detection circuit, and FIG. 3 is a characteristic diagram of a tensile force command with respect to speed deviation. 2-- Inverter, 6-- Main controller,
7----f, pattern generator, 15--P W M
Modulation section, 20---Target speed setter, 21---One speed comparison amplifier, 22---One motor current detection circuit, 23---One power running/brake discriminator, 25---・−
Changeover switch, 26------ Current interrupter, 31.32-
・-Induction motor, 41.42--Pulse generator.

Claims (1)

[Claims] 1. A power converter that outputs a variable voltage/variable frequency voltage, an induction motor for driving powered by the output of this power converter, a speed detection means for obtaining a detected speed signal corresponding to the speed of the vehicle, and a power running an operating means for generating a command, a brake command and a constant speed command; a means for generating a first slip frequency signal based on the power running command and the brake command; and a means for generating a second slip frequency signal based on the constant speed command. power converter control for controlling the output frequency and voltage of the power converter according to the first or second slip frequency signal and the detected speed signal to perform power running/regenerative braking operation of the induction motor; means for detecting the motor current;
In an electric vehicle control device comprising a main circuit opening means for opening the main circuit when the motor current falls below a predetermined value during regenerative braking operation, the main circuit opening means opens the main circuit when the constant speed command is generated. An electric vehicle control device characterized by being provided with a disabling means for disabling a function.