JPH0246105A - Controller for ac electric vehicle - Google Patents

Abstract

PURPOSE:To block overcurrent of a converter caused by shifted magnetization of a transformer, by stopping operation of the converter and an inverter during passage of an AC electric vehicle through a section and for a predetermined time after passage of the AC electric vehicle therethrough. CONSTITUTION:A section detecting circuit 9 detects no-voltage during an interval when an AC electric vehicle is in a section and provides the detected no- voltage as a section detection signal. A timer circuit 11 provides signals for a predetermined time after a time point when provision of the section detection signal is stopped. A control stop circuit 10 receives output signals from the section detecting circuit 9 and the timer circuit 11 and provides control stop signals when any one of the section detecting circuit 9 or the timer circuit 11 provides a signal. An AND gate 12 provides no operation command signal to a converter control circuit 41 and an inverter control circuit 61 even if the operation command signal is provided so long as the control stop signal is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for an AC electric vehicle that runs by receiving AC power from an overhead wire having sections.

[Conventional technology]

FIG. 2 is a block diagram showing a conventional example of a control device for an AC electric vehicle, in which reference numeral l is an overhead wire, reference numeral 2 is a current collector, and reference numeral 3 is a current collector.
is a transformer, 4 is a converter that converts single-phase AC power to DC power, 5 is a filter capacitor that smoothes DC voltage, 6 is an inverter that converts DC power to 3-phase AC power, 7 is 3-phase AC power In the induction motor, 41 is a converter control circuit, 61 is an inverter control circuit, 8 is an operation command circuit, 9 is a section detection circuit, 10 is a control stop circuit, and 12 is an AND element.

In FIG. 2, when the driver of the AC electric vehicle operates the main controller to enter the operation notch, the operation command circuit 8 sends a driving command signal to the converter control circuit 41 and the inverter control circuit 61. Output. The converter control circuit 41 controls the converter 4 according to the operation command signal so that the voltage of the filter capacitor 5 becomes a predetermined value. The inverter control circuit 61 controls the inverter 6 according to the operation command to drive the three-phase induction motor 7. The section detection circuit 9 detects that the vehicle has entered the section and outputs a signal to the control stop circuit 10, and this control stop circuit 10 determines whether or not a driving command signal is output based on the section detection signal. Regardless, a control stop signal is output to the converter control circuit 41 and the inverter control circuit 61 via the AND element 12.

The secondary voltage of the transformer 3 is 3, the equivalent leakage inductance on the secondary side of the transformer 3 is Ls, and the secondary current of the transformer 3 is Is.
, the input voltage of converter 4 is ■.

Assuming that the DC voltage is (4) and the DC current is Id, the following relationships (1) and (2) (2) hold between them.

■,・l,=V,・I, −−−−−−
−m=−−−−−−−−・−(2) Is Fig. 3 a transformer? ! i
r It is a vector diagram showing the relationship between the current and voltage on the secondary side, and shows the relationship of equation (1). It should be noted that FIG. 3 (A) is a vector diagram during forward driving, and FIG. 3 (B) is a vector diagram during regenerative braking. That is, converter control circuit 41
is the transformer secondary voltage V.

The power factor of secondary current and
1, so that the DC voltage ■4 becomes the specified value.
It controls the phase angle θ with respect to the magnitude of the converter input voltage VC and the transformer secondary voltage .

However, it is well known that when an AC electric car receives power again after passing through a section, the transformer 3 becomes biased due to the phase of the power supply voltage, and especially when the voltage phase is zero and power is supplied, the maximum bias occurs. generate a condition. In this case, the magnetic flux density of the transformer 3 becomes unbalanced between the positive cycle and the negative cycle, and even though the maximum magnetic flux density reaches the saturation magnetic flux density in one cycle, the magnetic flux density is low in the other cycle. From this state, the maximum positive and negative magnetic flux densities reach equilibrium with a certain time constant. In the biased magnetic state, when the magnetic flux density reaches the saturation magnetic flux density or is at a level close to it, the equivalent leakage inductance on the secondary side of the transformer 3 decreases rapidly compared to the normal case. , Therefore, the secondary current 3 of the transformer 3, ie, the input current of the converter 4, increases rapidly and reaches the overcurrent protection level of the converter 4. The converter 4 is a circuit in which a semiconductor switching element such as a SIRISK or a gate turn-off SIRISK is configured in a bridge configuration, and the overcurrent protection circuit level is determined by the maximum controllable current of the semiconductor switching element.

Therefore, in the conventional example circuit shown in FIG. 2, if the control stop signal at the time of passing the section is canceled immediately after the AC electric vehicle passes the section, and the operation command signal is present, the converter 4 and the invercro Control is started, but if the transformer 3 is biased due to resupply of power at this time, there is a problem in that the input current of the converter 4 becomes an overcurrent. For this reason, conventionally, before entering a section, the driver turns off the notch of coasting or regenerative braking to stop the operation of the converter 4 and inverter 6, and then turns the notch off again after passing the section by coasting. It was then turned on and operation resumed.

(Problem to be Solved by the Invention) Since the conventional device requires the above-mentioned operation, if the notch-off is not performed due to an incorrect operation when passing through a section, the problem may occur due to biased magnetization of the transformer 3. Immediately after passing through the section, an overcurrent occurs, which may possibly damage the semiconductor elements in the converter 4.

SUMMARY OF THE INVENTION An object of the present invention is to avoid the risk of overcurrent destruction of a converter due to biased magnetization of a transformer when an AC electric vehicle passes through a section of overhead wires.

[Means to solve the problem]

In order to achieve the above object, the control i11 circuit of the present invention connects AC power taken into the vehicle from the overhead line via the current collector to the transformer, and the converter and inverter connected to the secondary side of the transformer. In the AC electric car configured to convert AC power of a desired voltage and frequency into AC power and supply it to a drive motor, a section detection means detects when the AC electric car passes through a section dividing an overhead wire. , a time limit means for detecting a predetermined time from the time when the section passes, and a control stop means for stopping the converter and the inverter while the section detection means or the time limit means are in operation.

[Effect]

In this invention, since the biased magnetic state that occurs immediately after the transformer of an AC electric car passes a section will disappear over time, even if a driving command signal is output when the electric car passes the section. , by providing a time-limiting means that prevents the operation command signal from being given to the converter and inverter for a certain period of time after passing the section, and by stopping these converters and inverters, it is possible to prevent converter failure caused by biased magnetization of the transformer. This prevents overcurrent.

[Embodiment] The first [ffl] is a block diagram showing an embodiment of the present invention, and FIG. .The names, uses, and functions of the three-phase induction motor 7, operation command circuit 8, section detection circuit 9, control stop circuit 10, AND element 12, converter control circuit 41, and inverter control circuit 61 are as in the conventional example shown in FIG. Since these have already been explained, their explanation will be omitted.

In the present invention, a timer circuit 11 is provided which receives a signal from the section detection circuit 9 and outputs a signal instructing the control stop circuit 10 to stop the control for a certain period of time. That is, the section detection circuit 9 composed of voltage relays is
While the AC electric car is in the section, no voltage is detected and this is output as a section detection signal.

The timer circuit 11 inputs the output signal of the section detection circuit 9, and outputs a signal for a certain period of time from the time when the section detection signal disappears. The control stop circuit 10 receives the output signals of the section detection circuit 9 and the timer circuit 11, and outputs a control stop signal while either signal is being output.

The driving command circuit 8 determines the output signal of the master controller operated by the driver and outputs a driving command signal.

Since the AND element 12 inputs this operation command signal and the control stop signal, the timer circuit 1
1, even if the driving command signal is output, this driving command signal is not given to the converter control circuit 41 and the inverter control circuit 61.
After the time set by the timer circuit 11 has elapsed, the converter 4 and inverter 6 will restart their operation, but at that time the biased magnetization of the transformer 3 has already been resolved.
There is no risk that the converter 4 will overcurrent.

[Effects of the Invention] According to the present invention, when the AC electric car passes through a section of overhead wires, a voltage is applied to the transformer mounted on the AC electric car after the transformer is once de-energized. However, depending on the voltage phase when reapplying,
This transformer will be biased by 6 degrees, and this biased magnetization may cause overcurrent damage to the converter connected to the secondary side of the transformer. By providing a control circuit that keeps the converter in a stopped state until the problem is resolved, damage to the converter can be reliably avoided even if the driver erroneously outputs a driving command signal and passes through the section. It will be done.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a block diagram showing an embodiment of the present invention.
The figure is a block diagram showing a conventional example of a control circuit for an AC electric vehicle, and FIG. 3 is a vector diagram showing the relationship between current and voltage on the secondary side of a transformer. 1... Overhead line, 2... Current collector, 3... Transformer, 4...
...Converter, 5...Filter capacitor, 6...
・Inverter, 7... 3-phase induction motor, 8... Operation command circuit, 9... Section detection circuit, 10... Control stop circuit, 11... Timer circuit, 12... AND element , 41... converter control circuit, 61... inverter control circuit. Tor 31゜(A) Figure A

Claims (1)

[Claims] 1) The AC power taken into the train from the overhead wire via the current collector is converted into AC power of the desired voltage and frequency by a transformer, a converter and an inverter connected to the secondary side of the transformer, and used for driving. In an AC electric car configured to supply electricity to an electric motor, a section detection means for detecting when the AC electric car passes through a section dividing an overhead wire, a time limit means for detecting a certain period of time from the time when the AC electric car passes through the section; 1. A control device for an AC electric vehicle, comprising control and stop means for stopping the converter and the inverter while the section detection means or time limit means is in operation.