JPS59117401A - Power converter for vehicle - Google Patents

Abstract

PURPOSE:To sharpen the rise of the voltage of a filter capacitor by selecting the resistance value of a current reducing resistor so that the attenuation rate as a resonance circuit becomes a vibrating manner. CONSTITUTION:When a railcar starts, only a switch 3 is closed to charge a filter capacitor 6 through a current reducing resisltor 4. Since the resistance value of the resistor 4 is selected so that the attenuation rate as a vibrating circuit of a filter reactor 5 and the capacitor 6 becomes smaller than 1 in a vibrating manner, the voltage Vc' of the capacitor 6 abruptly rises in a vibrating waveform W state. The resistor 4 is shortcircuited at the time point P when the voltage Vc' becomes the level of 70-80% of the final value. Further, an energization signal cc' is fed to allow a power converter 7 to perform its function, and the load current by the converter 7 performs the parallel resistance effect of the capacitor 6, thereby suppressing an overshoot.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power conversion device for a vehicle that supplies power from an overhead line to a main motor via a power converter, and in particular, a power conversion device for a vehicle that shortens a 9-hour delay when starting an electric vehicle. 0 Regarding improvements to equipment In the electric vehicle drive system that has been widely used in the past, in which the voltage of the main motor is controlled by sequentially shorting the starting resistor using a cam contactor during start-up, the driver must use the master controller when starting the electric vehicle. When you operate the handle and give the notch signal,
Immediately, voltage is applied to the main motor to generate driving force. On the other hand, in an electric vehicle drive system that controls the traction motor via a power converter, a filter reactor and a filter capacitor for suppressing harmonic current are provided between the overhead wire and the power converter, so the traction motor is It is necessary to charge the filter capacitor before putting the power converter into operation to supply power. For this reason, in the latter case, there is a delay in the time between operating the mascon handle and feeling the driving force in the body, resulting in a feeling of discomfort between the two operations.

Next, let's talk about the time delay when starting an electric vehicle mentioned above.
This will be explained with reference to FIGS.

Figure 1 shows the basic configuration of a vehicle power converter system that uses a power converter. 1 is an overhead line, 2 is a current collector, 3, 3
' is a switch, 4 is a current reducing resistor, 5 is a filter reactor, 6 is a filter capacitor, 7 is a power converter, 8 is a motor group consisting of multiple main motors, and 9 is a rail. Here, the filter capacitor The output side of 6 is connected to a power converter 7 via a positive bus P and a negative bus N. Since such technology is commonly used, a detailed explanation will be omitted, and the contents of the power conversion related portion will be shown below.

FIGS. 2 and 3 show an example of an armature flange device and another example of a 3-phase VV representing the contents of the power conversion-related parts in FIG. 1.
FIG. 2 is a configuration diagram showing a VF inverter.

In other words, in FIG. 2, the motor group 81 has the armatures of a plurality of DC motors 811, 812, . . . -813 connected in series, and the positive bus P is directly connected to the motor group 81. The power converter 71, which is a Chisaki Tsuba device, is arranged between the motor group 81 and the negative bus N. Here, the power converter 7! is the main thyristor 711 for the chopper. Auxiliary thyristor 712. Commutation capacitor 71
3. Commutation reactor 714 and feedback diode 715
Consisting of However, in this example, the main thyristor 711. Both the auxiliary thyristor 712 uses a reverse conducting thyristor. It is also possible to use a gate turn-off thyristor, a static induction thyristor, a transistor, etc. as the main thyristor 711 for the chopper, and in this case, the auxiliary thyristor 7
12° commutation capacitor 713 and commutation reactor 71
It is well known that 4 is no longer necessary.

Further, in FIG. 3, a power converter 72, which is a three-phase inverter, is configured to drive a motor group 82, that is, a plurality of AC motors 821, 822, . . . 823 connected in parallel. Here, the power converter 72
is a well-known auxiliary impulse commutation method, and the first phase component as shown in the example, therefore, the main thyristor 721
, 722, auxiliary thyristor 723, 724, commutation capacitor 725, commutation reactor 726, and this lζ
0 consisting of the corresponding second phase and third phase, and
In this example, reverse conducting thyristors are used for the main thyristors 721 and 722, and reverse blocking thyristors are used for the auxiliary thyristors 723 and 724. Note that the main thyristor 72
It is possible to use gate turn-off thyristors, electrostatic induction thyristors, transistors, etc. for auxiliary thyristors 723, 724, etc.
The fact that the commutating capacitor 725 and commutating reactor 726 are not required is the same as in FIG. 2. However, it is necessary to add a feedback diode in antiparallel to elements such as the gate turn-off risk.

In a vehicle power converter such as a power converter 7, a filter reactor 5 is used because the power converter 7 generates harmonic current.
A filter capacitor 6 is provided to suppress this and reduce harmonic interference to the overhead wire 1.

Then, when starting the electric car, the voltage of the filter capacitor 6 is zero, so first, only the switch 3 is closed and the filter capacitor 6 is charged via the current reducing resistor 4. At this time, the voltage of the filter capacitor 6 is zero. (1) Prevent inrush current from flowing. Further, the switch 3' charged with the filter capacitor 6 is closed, the current reducing resistor 4 is short-circuited, and the motor group 8 is started to operate by the power converter 7.

As shown in the figure, a series resonant circuit is formed by a filter reactor 5°, a filter capacitor 6, and a current reducing resistor 4, but if the terminal voltage of the filter capacitor 6 overshoots, the overvoltage responsibility of the power converter 7 becomes Therefore, the value of the current reducing resistor 4 is generally selected such that the damping factor as a resonant circuit is greater than 1 to avoid vibrations. For this reason, in the operation of a conventional power converter-based vehicle power converter, there is a time delay between when the filter capacitor 6 is charged and when the power converter 7 is ready for operation, as described above. Ta. This is as shown in Fig. 4. ◇ Fig. 4 is a time transition diagram of the waveforms of various parts shown to explain the occurrence of time delay due to the conventional method, where NT is the notch signal and vo is the filter capacitor 6. The voltage, CC is the energization signal of the power converter 7, and TO is the dead time.

That is, if the switch 3 is closed immediately after the notch is turned on by the mask controller handle operation at the current time TI, and therefore the notch signal NT rises, the filter capacitor 6
The voltage vO rises in an overbraking curve close to an exponential function. Further, at time T2 when this voltage 0 reaches almost the final value, the switch 3' is closed as described above, the current reducing resistor 4 is short-circuited, and the energizing signal CC is sent out. Therefore, the electric motor group 8 is operated by the power converter 7. Here, between time points T, , T2, that is, (T2-T+) corresponds to the dead time To, 0
It is clear that after the notch is once turned off at time T3 while the electric vehicle is running, and therefore the notch signal NT falls, the dead time To similarly occurs when the notch is turned on again. Such a time delay can reach about 0.2 to 0.3 seconds, and this is felt by the body as a time difference between when the driver operates the mascon handle and when the driving force is actually generated. It had become a thing.

The present invention has been made in order to eliminate the above-mentioned problems, and the resistance value of the current reducing resistor portion is selected so that the damping rate due to the resonant circuit becomes oscillatory without changing the basic circuit configuration. In addition, the present invention provides an exceptional device that uses a starting method that short-circuits the current reducing resistor portion and accelerates the performance of the power conversion portion by making the rise of the filter capacitor voltage steeper. As mentioned above, the present invention can be applied to the device shown in FIG. 1, and more specifically to the example shown in FIG. 2 or 3, without any loss in the basic circuit configuration of the conventional system. be. A detailed explanation of the circuit configuration will be omitted here, and the explanation will be based on the basic circuit configuration of FIG. 1 with reference to FIG. 5, which is similar to FIG. 4.

FIG. 5 is a time transition diagram of waveforms of various parts shown to facilitate understanding of the effects of the present invention, where: ■C' is the voltage of the filter capacitor 6, CC' is the energization signal of the power converter 7, and T
o' is dead time. In the figure, the same reference numerals as in Figure 4 indicate parts with the same content.The first thing to note is that the voltage Vo' of the filter capacitor 6 rises based on the initial vibration waveform W. There is a particular thing. and,
This is done by reducing the resistance value of the current reducing resistor 4 in the circuit configuration shown in FIG. This is because the damping factor of the oscillating circuit with the filter capacitor 6 is selected to be smaller than 1 and oscillatory.

Now, at time T1, when the filter capacitor 6 is charged by the notion through the current reducing resistor 4, the voltage ■0
' is a vibration waveform W-shaped with a steep rise. If charging continues as it is, the voltage Vo' will become overgine as shown by the broken line, but this voltage
Pick up a point P having a level A between 70 and 80 degrees of the final value of o', thus short-circuiting the current reducing resistor 4 at the time T, /. It is assumed that the power converter 7 functions when the energization signal CC' is sent out. Than this,
When the power converter 7 starts operating, the load current from the power converter 7 causes a parallel resistance effect of the filter capacitor 6, and the overshoot is suppressed.
A waveform as shown in the example is obtained as the pulsating waveform R including the load. Therefore, the dead time TO' is (TO'=T2
'-Tt).

Therefore, if the circuit configuration shown in FIG.
You can get owo. Furthermore, it is clear that the same effect can be obtained even if the electric vehicle is notched off once after running and then turned on again.

As described above, according to the present invention, it is possible to provide an exceptional power conversion device for a vehicle that can improve electric vehicle starting performance and eliminate discomfort felt by a driver.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of a vehicle power conversion device that employs a power converter, Figs. The figure is a time transition diagram of various waveforms showing the state of occurrence of time delay in the conventional method.
Fig. 5 is a time transition diagram of waveforms of various parts shown to facilitate understanding of the effects of the present invention.
4...Reducing current resistor, 5...Filter reactor, 6...Filter capacitor, 7,7
1.72...Power converter, 8.81.82...
...Electric motor group, 9...Rail, NT,
NT'...Notch signal, vo, ■o'...
・Voltage of filter capacitor 6, CC, CC'...-
... Energization signal of power converter 7, To t'ro...
・Dead time・ Patent applicant Toyo Denki Seizo Co., Ltd. Representative Atsushi Doi Figure 1 Figure 4 Ko, Figure 5

Claims (1)

[Claims] A power converter equipped with a group of fixed electronic switches that can be made conductive or non-conductive depending on a control signal applied to a control electrode, a circuit breaker interposed between the power converter and a current collector, and a filter for suppressing harmonics. A resonant circuit is constructed from a reactor, a filter capacitor, and a current reducing resistor for suppressing inrush current to the filter capacitor, and the value of the current reducing resistor is selected so that the damping rate as the resonant circuit becomes oscillatory. a series resonant circuit, and a switch for short-circuiting the current-reducing resistor, and short-circuiting the current-reducing resistor immediately before the voltage of the filter capacitor exceeds when starting the electric vehicle. , a power conversion device for a vehicle, characterized in that the control signal is transmitted.