JPH0446042B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control device for an electric vehicle using insulated wheels such as rubber tires. Regarding a control device.

[Background of the invention]

Reflecting the recent trend towards energy conservation, even in the control of electric vehicles, the main circuit is becoming contactless in order to reduce power consumption and become maintenance-free. One way to achieve this is to use a control system that uses a DC motor and connects an armature chopper in series with the DC motor to chop the main circuit current. This method has already been put into practical use due to rapid advances in semiconductors. In addition, with the aim of further improving adhesive performance, there is a method of converting DC power into three-phase alternating current and driving a three-phase induction motor to control electric cars, but this method has already entered the stage of practical application. ing.

The case where these two methods are applied to an electric vehicle using insulated wheels will be explained with reference to FIGS. 1 to 7.

FIG. 1 is a simplified diagram of the main circuit of the armature chopper. 1 is a DC power source of a substation, 2 is a positive overhead contact line, and 3 is a negative overhead line, which are grounded via a grounding detection device 4 provided at the substation. 5 is the positive current collector of the electric car, 6
is a negative current collector, and 7 is a breaker. The current flowing through the main motor 8, which is a load, is controlled by an armature chopper 10, which is a control device. When the armature chopper is on, the armature current is 1 → 2 → 5 →
It flows along the path 7→8→9→10→6→3→1. When the armature chopper is off, the armature current flows along the path 8→9→11→8. At this time, 9 is a reactor for smoothing the armature current, and 11 is a diode for circulating the armature current.

Armature chopper circuits for controlling armature current in this control system are roughly classified into the systems shown in FIG. 2 and FIG. 3, depending on the type of semiconductor used. There are other chopper systems, but these two are the ones that are mainly used. Figure 2 shows a series arc-extinguishing type repulsion pulse commutation type chipper 13 using a reverse conduction type thyristor. This system is adopted in most main circuit choppers, and is composed of a main thyristor 14, an auxiliary thyristor 15, a commutating reactor 16, and a commutating capacitor 17.
Since the commutation mode of this method is extremely common, it will be omitted here.

Figure 3 shows a GTO chopper 18 that uses a gate turn-off thyristor (GTO) with a self-extinguishing function, which has become rapidly larger in capacity in recent years and can now be applied to main circuit choppers. It is generally composed of a gate turn-off thyristor 19 and a bypass diode 20 connected in antiparallel. Gate turn-off thyristors can be controlled on and off by gate current, so
This is a very simple circuit.

FIG. 4 is a simplified diagram of the main circuit of an electric vehicle using an inverter device. Although there are many possible inverter control methods, such as a current control method, a variable voltage square wave method, and a pulse width modulation method, the most common pulse width modulation method will be described here.

The equipment of the electric car other than the car body 12a is the same as that shown in FIG. 1. The main circuit in the electric car is a circuit breaker 7a,
It is composed of an inverter device 21 as a control device and an induction motor 22 as a load.

The inverter device 21 has built-in stepping elements for three phases, and by changing the stepping time of each stepping element, three-phase alternating current can be obtained, which drives the three-phase induction motor 22. .

Similarly to the case of the armature chopper, the chopping circuit in this control method is roughly divided into two types, as shown in FIG. 5 and FIG. 6, depending on the type of semiconductor used.

FIG. 5 shows a chopping circuit 23 for one phase using reverse conduction type thyristors, and three sets of this are used in a three-phase inverter. Main thyristors 24, 25,
Auxiliary thyristor 26, 27, commutation reactor 2
8 and a commutating capacitor 29. Since the commutation mode of this system is almost the same as that shown in FIG. 2, it is omitted here.

FIG. 6 shows a GTO chopping circuit 30 using a gate turn-off thyristor. This circuit also has gate turn-off thyristor 3 as shown in Fig. 3.
1 and 32, and bypass diodes 33 and 34.

What these circuits shown in FIGS. 1 to 6 have in common is that the current flowing through the main circuit is stepped. When a large current is turned on and off in a certain period, Figures 2 to 3 and 5 to 6
A large rectangular wave current flows through the main thyristor and GTO sections in the figure. Furthermore, since the circuits shown in FIGS. 2 and 5 are commutation circuits, an oscillating current flows through the auxiliary thyristor and the commutation element. These rectangular wave currents and oscillating currents are a type of distorted wave alternating current.

Generally, a distorted wave alternating current can be considered as a collection of many positive arc waves having different frequencies and maximum values according to a Fourier series. The frequency of the distorted wave is affected by the chopping frequency, and the maximum value of the distorted wave is
Affected by the magnitude of the main motor current. Therefore,
The current flowing in the main circuit and the current flowing in the overhead contact line contain harmonic current components, and it is expected that these harmonic components will cause problems such as inductive disturbances to other communication equipment. Therefore, in order to reduce this harmonic current, a filter device composed of a reactor and a capacitor is used. However, in electric cars using insulated wheels, there is another path through which harmonic current flows. An example of this problem will be explained in the case of an armature chopper that controls the main circuit.

FIG. 7 shows a path through which harmonic current leaks from the chopper circuit 10.

The main circuit connection diagram is the same as that in FIG. However, 3
9 and 40 are the above-mentioned reactors and capacitors. 35 is a stray capacitance between the vehicle body 12 and the ground, and 36 is a stray capacitance between the negative contact line and the ground. Further, 41 is a stray capacitance that exists between the main circuit and the vehicle body.

When the armature chopper 10 is turned on, the positive side potential of the armature chopper 10 becomes the same potential as the negative contact wire 3, and when the armature chopper 10 is turned off, the positive side potential of the armature chopper 10 becomes almost positive. It becomes equal to the electric potential of the overhead contact line. In other words, a type of pulsating voltage source exists.

This pulsating current voltage source connects the main circuit to the car body, from the car body to the ground via the stray capacitance that exists between each, and then from the ground to the negative contact line 3, which reduces the stray capacitance between them. and flows into the negative overhead contact line. Furthermore, since the capacitance between the ground and the negative contact line exists in a dispersed manner, the return current also flows into the negative contact line where no return current is flowing.

Here, there is a stray capacitance between the positive contact wire and the ground, but there is a stray capacitance on the positive potential side of the train.
Since a filter device consisting of 9 and 40 reactors and capacitors is provided, the pulsating current in the positive power line is small and does not pose a problem.

37 is a communication system loop, such as a train detection block loop, an IR guide line, etc.

A problem arises in that the harmonic components flowing in the negative overhead contact line generate an induced voltage in the communication system loop 37, which impairs the function of the communication system.

Note that in electric cars using iron wheels, the car body is connected to the negative side of the main circuit, so pulsating current does not flow into the negative overhead contact line.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for an electric vehicle that does not cause induction disturbances to communication equipment, which is ground equipment, when the main circuit current or auxiliary equipment current is controlled on and off.

[Summary of the invention]

The gist of the present invention is that, in an electric vehicle using insulated wheels, an AC impedance element is connected between the vehicle body and the negative current collector.

[Embodiments of the invention]

FIG. 8 shows an embodiment of the present invention. The case of an armature chopper that controls the main circuit as in the conventional case will be shown. This is also applicable to inverter devices. FIG. 8 shows an AC impedance element 38 connected to the vehicle body and the positive side of the negative current collector, and the arrows indicate the paths through which harmonic current flows. Other equipment configurations and connections are the same as those shown in FIG. 7.

The harmonic components generated in the armature chopper 10 are:
The stray capacitor between the vehicle body and the thyristor element causes the current to flow into the vehicle body, but if the AC impedance element 38 is set lower than the AC impedance including the stray capacitor 35, the stray capacitor 36, and the negative power line, the magnitude of the harmonic current can be reduced. This portion flows through the low AC impedance element 38, and the harmonic current of the negative contact line becomes small.

Since the negative overhead contact line does not contain harmonic components, the voltage induced in the signal communication system loop of the ground equipment 37 decreases.

FIG. 9 shows the configuration of the low impedance element 38. 382 is a capacitor that bypasses harmonic components, 381 is a resistor that limits the current applied to the capacitor, and 383 is a discharge resistance of the capacitor.

By additionally installing this element, the induced voltage in the signal communication system loop 37 of the ground equipment is reduced, and the operation of the signal communication system is no longer hindered.

Although the main circuit control device has been described above, similar technology can be applied to inverter devices that create on-board auxiliary power sources and induction commutator motor generators using thyristors.

〔Effect of the invention〕

According to the present invention, it is possible to reduce harmonic components flowing into the negative overhead contact line, and therefore it is possible to reduce induction disturbances to ground equipment.

[Brief explanation of the drawing]

Figures 1 and 4 are high-voltage circuit diagrams of an electric vehicle using conventional insulated wheels, Figures 2, 3, 5, and 6 are detailed diagrams of the conventional tip section, and Figure 7. 8 is an explanatory diagram showing the problems of the prior art, and FIGS. 8 and 9 are a high voltage circuit diagram and an additional circuit diagram of the present invention, respectively. 5...Positive current collector, 6...Negative current collector, 8...
Main motor, 10... Armature chopper, 12... Vehicle body, 21... Inverter device, 22... Induction motor, 38... Low impedance element which is an AC impedance element, 381... Limiting resistor, 382
...Bypass capacitor, 383...Discharge resistor.

Claims (1)

[Scope of Claims] 1. An induction disturbance prevention device for an electric vehicle having an AC impedance element 38, in which the electric vehicle has a vehicle body 12 supported by insulated wheels, and a control device for a traveling device or an auxiliary machine. 1
0 and 21 are constituted by chopping elements,
An induction disturbance prevention device for an electric vehicle, which has a positive current collector 5 and a negative current collector 6, and the AC impedance element 38 connects between the vehicle body 12 and the negative current collector 6. 2. The inductive disturbance prevention device for an electric vehicle according to claim 1, wherein the AC impedance element 38 is a capacitor 382. 3. The inductive disturbance prevention device for an electric vehicle according to claim 1, wherein the AC impedance element 38 is a capacitor 382 and a resistor 381 connected in series.