JPS6077611A - Controlling method of electric railcar - Google Patents

Abstract

PURPOSE:To enable to rapidly and stably start and accelerate by setting the rotating frequency of an induction motor to negative value at backward starting time. CONSTITUTION:When an electric railcar moves backward at a slope starting time, the output of backward detecting means 15 becomes ''1'', and switches 13, 16 are shifted to ''1'' sides. Thus, when the inverter start command signal 4 is outputted, the starting time inverter frequency EIP1 is inputted to a sampleholding circuit 6, and held. After the inverter start is then initiated, the value FXP produced by adding the rotating frequency of the induction motor and a reference slip frequency is compared by a comparator 8 with the FIP1. When becoming FXP>=FIP1, a switch 9 is shifted to ''1'' side. The maximum value detecting means 17 outputs as the inverter frequency 10 larger one of the output of the switch 9 and the minimum inverter frequency FLIM.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for controlling an electric vehicle driven by an induction motor controlled by a variable voltage variable frequency inverter.

[Technical Background of the Invention and Problems thereof] FIG. 1 is a conventional control flowchart 1 to 1 when starting an electric vehicle driven by an induction lightning IFII machine using a variable voltage variable frequency inverter. Moreover, FIG. 2 shows the relationship of each frequency with respect to time t in this case.

Conventionally, when the inverter start command signal 4 is input, a value obtained by adding the starting induction motor rotation frequency (IFRI) 2 and the starting slip frequency (FSO) 3 is input to the sampling hold circuit 6 immediately before the switch 5 is switched. be done. When the switch 5 is switched to the 1'' side, a closed loop is formed with the sampling hold circuit 6.
The inverter frequency (FIPl) 7 at startup is kept constant based on its hold value.

When the ratio V/F between the inverter output voltage V and the inverter output frequency F is kept constant, constant torque control is achieved. When performing this constant torque control, the secondary current JR of the induction motor and the slip frequency FS are in a proportional relationship, and the reference slip frequency 1 can be determined as FSI from the current limit value pattern showing this proportional relationship. In addition, the induction motor rotation frequency (IF
RI)2 is positive or O because it only looks at the number of rotations.

In FIG. 2, the slip frequency FS is FS=FIP1-FR from startup to time tb. Time t from startup
Between b, constant current control is performed by the inverter output voltage V. Therefore, the torque T during this period is T=K (IR)
2 /FS (K is a constant), so when the induction motor rotation frequency FRO at startup is small and the slip frequency FS is large, the torque T is small, and as FR gradually increases, T gradually increases, electric car soft star 1
I can write ~. Furthermore, an adder FX of the induction motor rotation frequency FR after startup and the reference slip frequency FS1
The comparator 8 compares the value of FXP=FR+FS1, which is P, with the startup inverter frequency FIP1. In comparison, when FXP>GIPI, switch 9 switches to the "1" side at that point, so inverter frequency 10 becomes F.
Switching from IPI to FXP value, starting constant current control 11 using slip frequency, and starting V/F constant pattern operation 12
Move to.

According to this control, when the line I9 is flat or on a downhill slope, the FR increases after startup, so it is possible to shift to constant V/F control, and the soft start of electric cars is effective. It allows for very smooth acceleration.

However, in the above-mentioned control, the induction motor rotation frequency FR is always set to 0 or more, so in cases such as starting when the route is on an uphill slope, as shown in Figure 3, the moment the inverter start command 4 is given, the vehicle Even if the value is retreating, it is viewed as the absolute value IFRI. Therefore, the value of the inverter frequency FIP1 at startup is the sum of the induction motor rotation frequency (IFROI) at that time and the slip frequency at startup (FSO)3. Therefore, FIP1=l FRO1+FSO...A.

At startup, the relationship FIP1-FRO=FSO should originally hold, and since FRO<0 now, FIP1=-lFROl+Fso...B.

Therefore, according to this kind of control, the inverter frequency FIP1 at the time of starting during reversing is calculated to be larger by 21 FRO1, so in the case of starting on a slope mentioned above, the actual slip frequency FS becomes FS=FSO+2 l FR
OL becomes larger and the starting torque becomes smaller, so the third
As shown in the diagram, even after starting up, the backward speed continued to increase, and there was a risk that the vehicle would not be able to accelerate. In addition, even if the electric vehicle starts to accelerate in the forward direction, it will accelerate very slowly, and if high-frequency pulses are used at startup due to inverter pulse width modulation control, etc., the time to start will increase. becomes longer, creating a thermally severe condition for the switching elements of the inverter.

In this way, if the induction motor rotation frequency is always viewed as an absolute value, the above-mentioned problem occurs when starting backwards on an uphill slope.

[Objective of the Invention 1 The object of the present invention is to provide a method for starting an electric vehicle driven by an induction electric hoe controlled by a variable voltage variable frequency inverter at a place where backward starting occurs, such as when going up a slope. To provide an electric vehicle control method capable of starting smoothly and stably.

[Summary of the Invention] The electric vehicle control method according to the present invention uses the rotational frequency of the induction motor as a debt during reverse start-up, determines an appropriate inverter frequency using the same calculation formula as during normal start-up, and sets a lower limit for the inverter frequency. By setting the value and decreasing the slip frequency at the time of reverse start-up and increasing the start-up torque, prompt and stable start-up and acceleration are possible.

[Embodiments of the invention] The present invention will be described based on an embodiment shown in the drawings.

In FIG. 4, the activation method in normal times, that is, when the output of the backward detection means 15 is 0'', is the same as that explained in FIG.

When starting on a slope, when the brake is released, the electric vehicle starts to move backward, and the output of the backward detection means 15 becomes ++ 1 ++. As a result, the switch 13 changes to b, so the induction motor rotation frequency 2 is multiplied by 11 and changes from a positive value to a negative value, and the switch 16 also switches to the '1 side, so the slip frequency at this time is equal to the slip frequency at reverse start. This will be the FSO on the 14th side. If inverter start command signal 4 is output in such a state, induction motor rotation frequency at start-up FRO=-11FROI (however, 1
Bi' represents the absolute value) is the slip frequency FS at backward start.
The value obtained by adding O (Equation 8) is input to the sampling and holding circuit 6 immediately before the switch 5 is switched. A closed loop is formed between the switch 5 and the hold circuit 6, so that the inverter frequency (FIPl) 7 at startup is held constant based on the hold value.

In order to increase the torque, the reverse starting slip frequency 14 is smaller than the starting slip frequency 3 when the vehicle is flat.

When the inverter is started and the vehicle starts accelerating in the forward direction, FXP (= FR + FS
1) is compared with the start-up inverter frequency FIP1 by the comparator 8, and when it is determined that FXP2≧-FIPI, the switch 9 is switched to the ``1'' side. At this time switch 9
The output of is compared with the minimum inverter frequency (FLIM) 18 by the maximum value detection means 17, and the larger one is outputted as the inverter frequency 10. At the same time, the output of the comparator 8 shifts to constant current control 11 based on the slip frequency.
Immediately after that, V/F constant pattern operation 12 is started. Here, the reason why the output of the maximum value detection means 17 is set to be equal to or higher than the minimum inverter frequency (FLIM) 18 is as follows. That is, in FIG. 7, which shows a simplified configuration of the inverter, if the inverter frequency is FXP, the input side of the converter 23 is connected to the pantograph 2o as well as the FXP.
A pulsating current with a frequency six times that of the current flows. There is a filter circuit on the input side of the converter consisting of a beam axle 21 and a capacitor 22, but when the value of FXPx6 approaches the resonant frequency of the filter circuit, the inverter circuit begins to vibrate, and the induction motor 24 is activated by its output. controlled. Therefore, the maximum value detection means 17 shown in FIG. 4 is used to ensure that the inverter frequency 10 is equal to or higher than the minimum inverter frequency (FLIM) 18 even when the inverter frequency 10 is at its lowest during startup.

Since the induction motor rotation frequency 2 is at least 0 when backward starting is not considered, it is sufficient to set it to a value of 18 or more at the time of starting. However, when considering backward startup, the output FR of the switch 13 takes a negative value, so the maximum value detection means 17 is required because the inverter frequency 7 at startup may become less than the minimum inverter frequency (FLIM>18).

5 and 6 show the contents explained in the configuration of FIG. 4 in terms of the relationship between frequency and time.

First, FIG. 5 will be explained in comparison with the configuration of FIG. 4. The horizontal axis is time 1. The tji axis is the same wave number of the inverter output and the rotation frequency of the induction motor.

When a vehicle stopped on an uphill slope releases its brakes at time ta, the vehicle accelerates in the opposite direction to its intended direction of travel and gradually moves backward. start. After the brake is released, inverter start command 4 is input at time t=Q 1
°', the output of the post-testing means 15 becomes "i"
Therefore, if the induction motor rotation frequency at time j'l t = O is (FR)), the induction motor rotation frequency (FR) used for calculation is at the time of inverter startup,
FR=-I FROl...C Also, the slip frequency (FSO) at the time of inverter startup is as follows:
Since the output of the backward detection means 15 is "1", the slip frequency at the start of backward movement is the value 14.

Therefore, the inverter frequency at startup (FIPl) is held by the sampling and hold circuit 6 at the moment the inverter startup command 4 becomes 1'', and is expressed by the following equation.

F TPl = FR + FSO = -IFRO1 + Fso -D This equation is the same as equation B given above. In the example of FIG. 5, since FIPl>FLIM, the inverter frequency (FIPl) 7 at startup is output as is as the inverter frequency 10.

When the inverter starts up, the conductive motor produces forward torque, and the vehicle's reverse speed (IFRI) decreases, the actual slip frequency (FS) shown in FIG. 5 gradually decreases.

Here, if (FS) is FR<O, then FS=FIP1+l FRl...E.

The torque T of the induction motor in this mode is T=K (IR)2 /FS...F, where the secondary current of the induction motor is (IR) and the constant is (K), so (
As FS) becomes smaller, the torque gradually increases.

Considering the sign of (FR), (FS)t FS=FI
P1-FR =FIP1-'(FXP-FSl) =FS1+ (FIPI-FXP)...G.

As the speed of the vehicle increases with the forward direction being positive, when FIP1=FXP in the G formula, that is, when the actual slip frequency (FS) matches the reference slip frequency (FSl) 1, the comparator 8 outputs "1'', and the switch 9 assumes the value of ``b'' inverter frequency 10. At the same time, it shifts to constant current control 11 using the slip frequency, and immediately after that, V/
F constant pattern operation 12 is started.

Next, the case shown in FIG. 6 will be explained. On an uphill slope, if the time from when the brake is released at time ta until the inverter start command 4 is input is long, or if the slope is steep, the inverter start command 4 is sent at time 1=0.
When the engine is turned on, the vehicle's rear 'J■ speed becomes large. This confrontation, startup frequency (FIPl) 7
The value of is the D formula % formula % explained in Figure 5, but since the IFROI is large, the value of (FIPl) is less than the value of the minimum inverter frequency ('FLIM) 18,
That is, FIPl<FLIM. Therefore,
The maximum value detection means 17 outputs (FLIM) as the value of the inverter frequency 10. When torque is generated in the forward direction (FR) gradually increases, (FXP) becomes equal to the starting inverter frequency (FIPI) 7, and when the comparator 8 switches the switch 9 to the "1" side,
The V/F constant pattern 12 is entered, but since the value of (FXP) is still smaller than the minimum inverter frequency (FLIM>18) from time tb to tc in FIG. IM) 18 is the value of the inverter frequency 10.

When FXP>FL IM after time tc, (FXP) is output as the value of inverter frequency 10 for the first time.

By the way, an example of a method for detecting the backward movement of a train will be explained below.

Figure 8 shows a pulse generator attached to the axle of an induction motor. The sensor 30a and the sensor J30b are the rotating gear 31
The rotational frequency of each is detected, but each has a phase difference of 90 degrees in electrical angle. Therefore, depending on whether the rotating gear 31 is moving forward or backward, a 90 degree delay or advance occurs between the signals of the sensors 30a and 30b as shown in FIG. 9, and by detecting this,
You can decide whether to move forward or backward.

In this way, in the present invention, a sign is added to the rotational frequency of the induction motor to make the forward rotation direction positive and the reverse rotation direction negative with respect to the commanded rotation direction, and the same calculation as during normal startup is performed even during reverse startup. Since the optimal inverter frequency can be determined, electric cars can be started quickly even if the route is uphill.

In addition, a lower limit value is set for the inverter output frequency to prevent the frequency of the AC component of the inverter input current from dropping to the resonant frequency of the filter circuit composed of the inverter input filter reactor and filter capacitor. , it is possible to start stably without vibration even when starting in reverse.

Furthermore, since the torque of the induction motor is increased by making the starting slip frequency smaller than the slip frequency during starting when starting in reverse, it is now possible to accelerate quickly.

[Effects of the Invention] As described above, according to the present invention, an electric vehicle driven by an induction motor controlled by a variable voltage variable frequency inverter can be started at a place where backward starting occurs, such as when going up a slope. Therefore, it is possible to provide an electric vehicle control method that can quickly and stably start the electric vehicle even if the vehicle is in J5 mode.

[Brief explanation of the drawing]

Figure 1 is a block diagram for explaining the conventional control method when starting an electric vehicle by driving an induction motor controlled by a variable voltage variable frequency inverter, and Figure 2 shows the control during normal startup in Figure 1. Figure 3, which is a diagram showing the relationship between time and each frequency for explanation, is similar to Figure 1 (Figure 4, which is a diagram showing the relationship between time and each frequency to explain control at the time of backward start) The figure is a block diagram for explaining one embodiment of the electric vehicle control method according to the present invention, and FIG.
In the figure, a diagram showing the relationship between time and each frequency according to control during reverse start-up, and FIG. 7 is a simplified configuration diagram of an induction motor drive system using a variable N-pressure variable frequency inverter. 1... Reference slip frequency, 2... Induction motor rotation frequency, 3... Slip frequency at startup, 4... Inverter start command, 5, 9, 13. 16... Switch, 6.
... Sampling hold circuit, 7... Inverter frequency at startup, 8... Comparator, 10... Inverter frequency, 11... Constant current control, 12... V/F constant pattern operation, 14.・Slip frequency at reverse start, 15
... Backward detection means, 17... Maximum value detection means, 18
... Minimum inverter frequency, 20 ... Pantograph, 21 ... Filter reactor, 22 ... Filter capacitor, 23 ... Converter, 24 ... Induction motor, 30a ... Sensor a, 30b. ...sensor b13
1...Rotating gear. Applicant's Representative Patent Attorney Takehiko Suzue Figure 5 Figure 2 Figure 7 2θ Figure 2 Director General of the Patent Office Kazuo Wakasugi 1. Display of the case I4 Hasho 58-186222 No. 2, Name of the invention Electric vehicle control method 3, Person making the amendment Relationship to the case Patent De Kazuto (307) Tourei Shibaura Electric Co., Ltd. 4, Agent 6 Subject of amendment Contents of amendments to the specification (1) Changed ``This is a simple groove 1 cutout diagram'' in the 17th stroke of page 16 of the specification to ``(a) simplified configuration diagram, Figure 8 shows the number of guides'' on the axle of the heartbeat. Figure 9 is a diagram of the signal waveform detected by the sensor of the odorless generator. ” he corrected.

Claims (1)

[Claims] (1) In an electric vehicle driven by an induction motor controlled by a variable voltage variable frequency inverter, when controlling the variable voltage variable frequency inverter, the vehicle may move backward even though a forward movement command is input. When it is detected that the rotational frequency of the induction motor is a negative value, the absolute value of the rotational frequency of the induction motor is subtracted from a preset slip frequency for backward startup to determine the inverter frequency at the time of backward startup. , if this inverter frequency at backward startup is equal to or higher than a lower limit value set for the output frequency of the variable voltage variable frequency inverter, the inverter frequency at backward startup is set as the output frequency at startup of the variable voltage variable frequency inverter; If the inverter frequency at the time of backward startup is below the lower limit value, the lower limit value is set as the startup output frequency of the variable voltage variable frequency inverter to start control the induction motor. (21) When determining the inverter frequency at reverse start, the slip frequency at reverse start is made smaller than the start slip frequency at flat state in order to increase the torque of the induction motor. Electric car control method.