JPH0576104A - Controller for ac electric vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] When an AC electric car starts up in a climbing direction on a sloping track, it does not fail to start up even if the DC intermediate circuit voltage rises due to backward start, so that it can start up smoothly. Especially. [Configuration] An overvoltage of the DC intermediate circuit that stops the main circuit, that is, a second set value that is lower than the first set value is set, and if the DC intermediate circuit voltage first reaches the second set value. , To prevent overvoltage by short-circuiting the positive electrode and negative electrode of the DC intermediate circuit via a resistor without stopping the main circuit,
Alternatively, the main circuit is not stopped and the positive electrode and the negative electrode of the DC intermediate circuit are connected to the resistance by a logical product of the AC electric vehicle being in the reverse start mode and the DC intermediate circuit voltage reaching the second set value. By short-circuiting via the overvoltage, the overvoltage is suppressed, and thereby the AC electric vehicle can be smoothly started in reverse without stopping the main circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an AC electric vehicle, which prevents a possibility that the AC electric vehicle will fail to start when the AC rail vehicle starts up a sloped track.

[0002]

2. Description of the Related Art FIG. 4 is a circuit diagram showing a conventional example of a control device for an AC electric vehicle. As shown in FIG. 4, the AC power supplied by the overhead wire 1 is taken into the AC electric vehicle by the pantograph 2, and is discharged from the wheels 5 to the rail 6 via the circuit breaker 3 and the transformer 4. The transformer 4 transforms this AC power into a desired voltage, and the rectifier 11 converts this AC power into DC power and outputs it to the DC intermediate circuit. The DC intermediate circuit is provided with a filter including the DC reactor 12 and the smoothing capacitor 13, and this filter removes the ripple component included in the DC power. The inverter 7 converts the DC power smoothed by the filter into AC power of a desired voltage and frequency, and drives the induction motor 8 connected to the wheel 5 at a variable speed with this AC power. The rectifier 11 may be composed of only a diode, but it is general that the output DC voltage can be controlled by a mixed bridge connection structure of a diode and a thyristor as shown in FIG.

A so-called DC intermediate circuit that connects the DC side of the rectifier 11 and the DC side of the inverter 7 is provided with a series circuit of a braking switch 14 and a dynamic braking resistor 15 to reduce the speed of the AC electric vehicle. Turns on the braking switch 14,
The electric power returned from the induction motor 8 to the DC intermediate circuit via the inverter 7 is consumed by the dynamic braking resistor 15. Further, since the rectifier 11 adjusts the output DC voltage as described above, the inverter 7 and the rectifier 11 may be damaged if the DC intermediate circuit voltage rises abnormally. Therefore, if the DC voltage detector 16 is provided and the DC intermediate circuit voltage exceeds the value set by the overvoltage setting unit 21, the overvoltage detector 22 as the first voltage detecting means constituted by the comparator detects this abnormal voltage. Then, the protection signal generating circuit 23 and the suppression switch 17 are instructed to start the operation. Since the protection signal generation circuit 23 gives a trip command to the circuit breaker 3 and gives an OFF command to all the switching elements constituting the inverter 7, the operation of the main circuit of the AC electric vehicle is stopped. Further, by the operation of the suppression switch 17, the positive electrode and the negative electrode of the DC intermediate circuit are short-circuited via the voltage suppression resistor 18, and the induction energy stored in the reactance of the DC reactor 12 and the induction motor 8 is transferred to the smoothing capacitor 13. Released
This suppresses the DC intermediate circuit voltage from further increasing.

[0004]

[Problems to be Solved by the Invention]
Stop in the middle of the sloping track and then start in the climbing direction
In order to try, the induction motor 8 is set to the power running state and the break
Than the torque generated by the induction motor 8 when the key is loosened
If the backward force due to the weight of the AC electric vehicle is larger,
This AC electric car has moved backwards
Continue until the generated torque of machine 8 exceeds the backward force,
Then start moving forward. This is so-called backward activation.
The output frequency of the inverter is F_IN, Induction motor 8 rotor
Frequency is F _RThen, the inverter frequency F_INAbsolute value of
Than rotor frequency F_RDuring the period when the absolute value of
AC electric car is opposite to the direction of travel due to the weight of both
It is a retreat area that moves in the direction of
Therefore, the induction motor 8 becomes a generator, and
Rugies flow into the DC intermediate circuit via the inverter 7.
It

FIG. 5 is an operation waveform diagram showing an operation mode of an AC electric vehicle equipped with the conventional circuit shown in FIG. 4. FIG. 5 shows changes in inverter frequency F _IN and rotor frequency F _R , and FIG. Each represents a change in the DC intermediate circuit current _ID . Here, on the left side of the time point T ₁ , there is a backward region in which the absolute value of the rotor frequency F _R is larger than the absolute value of the inverter frequency F _IN , so the induction motor 8 operates in the regenerative mode, and the DC intermediate circuit current I _D flows in the opposite direction, that is, from the induction motor 8 toward the inverter 7. To the right of T ₁ is a forward region where the absolute value of the inverter frequency F _IN is larger than the absolute value of the rotor frequency F _R , the induction motor 8 operates in the power running mode, and the DC intermediate circuit current _ID is in the forward direction. That is, the current flows from the inverter 7 to the induction motor 8.

FIG. 6 is an operation waveform diagram showing operation waveforms of various parts when the AC electric vehicle is reversely started. FIG. 6 shows changes in the rotor frequency F _R and FIG. 6 shows changes in the DC intermediate circuit current I _D. 6 shows changes in the DC intermediate circuit voltage V _D , respectively. Here, the time point T ₀ is the start time point in the climbing direction on the inclined track, the period from the time point T _{0 to the} time point T ₁ is the backward start time period, and the time point after the T ₁ time is the forward time period. In the case of the conventional circuit shown in FIG. 4, the DC intermediate circuit voltage V _D greatly increases during the backward starting period as indicated by the alternate long and short dash line in FIG. In the conventional circuit shown in FIG. 4, the overvoltage detector 22 detects the rise of the DC intermediate circuit voltage and commands the trip of the circuit breaker 3 and the stop of the inverter 7, so that the AC electric vehicle fails to start. There is inconvenience.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable an AC electric vehicle to be started smoothly in a climbing direction on a sloping track without failing to start even if the DC intermediate circuit voltage rises due to backward starting. To do.

[0008]

In order to achieve the above object, the control device for an AC electric vehicle according to the present invention converts the alternating current supplied from an overhead wire via a circuit breaker into direct current and outputs it to a direct current intermediate circuit. A rectifier and an inverter that is connected to this DC intermediate circuit to convert DC into AC of a desired voltage and frequency,
In an AC electric vehicle equipped with an induction motor that drives wheels using this inverter as a power source, if it is detected that the voltage of the DC intermediate circuit exceeds a first set value, a trip command to the circuit breaker is issued. It is provided with a first voltage detecting means for issuing a simultaneous OFF command to the switching elements forming the inverter and an operation command to a resistance short-circuit means for short-circuiting the positive electrode and the negative electrode of the DC intermediate circuit via a resistor. The control device for an AC electric vehicle includes second voltage detecting means for detecting that the DC intermediate circuit voltage has reached a second set value lower than the first set value, and the second voltage detecting means is provided. If it operates, an operation command is given to the resistance short-circuit means, or even if the second voltage detection means and the induction motor are in the power running operation, the induction motor outputs the DC intermediate voltage. A backward activation mode detecting means for detecting a state in which electric power is regenerated, and a logical product calculating means for calculating a logical product of an output signal of the second voltage detecting means and an output signal of the backward starting mode detecting means, The resistance short circuit means is operated by the output signal of the logical product calculation means.

[0009]

According to the present invention, the overvoltage of the DC intermediate circuit for stopping the main circuit, that is, the second set value lower than the first set value is set, and the DC intermediate circuit voltage is first set to the second set value. If the value is reached, the main circuit is not stopped and the positive and negative electrodes of the DC intermediate circuit are short-circuited via a resistor to suppress overvoltage, or if the AC electric vehicle is in reverse start mode and the DC intermediate Due to the logical product that the circuit voltage reaches the second set value, the main circuit is not stopped, and the positive and negative electrodes of the DC intermediate circuit are short-circuited via the resistor to suppress the overvoltage. It is intended to smoothly start up the AC electric vehicle in reverse without stopping the main circuit.

[0010]

1 is a circuit diagram showing a first embodiment of the present invention. An overhead line 1, a pantograph 2, a circuit breaker 3, a transformer 4, wheels 5 are shown in the circuit of the first embodiment. , Rail 6, inverter 7, induction motor 8, rectifier 11, DC reactor 12, smoothing capacitor 13, braking switch 1
4, dynamic braking resistor 15, DC voltage detector 16, suppression switch 17, voltage suppression resistor 18, overvoltage setting device 21,
Since the names, applications, and functions of the overvoltage detector 22 as the first voltage detecting means and the protection signal generating circuit 23 are the same as those described in the conventional example circuit described above with reference to FIG. 4, their description will be omitted. ..

In the first embodiment circuit shown in FIG. 1, the suppression voltage setting unit 31 sets a second setting value lower than the first setting value set by the overvoltage setting unit 21, and the DC intermediate circuit voltage V _If the suppression voltage detector 32 as the second voltage detecting means detects that _D has reached this set value, the OR element 33
To start the operation to the suppression switch 17 via. However, since the suppression voltage detector 32 gives an operation command only to the suppression switch 17 and does not give it to the protection signal generation circuit 23, even if the DC intermediate circuit voltage starts to rise during the reverse start, the suppression switch 17 and the voltage suppression resistor 18 are provided. Only the voltage suppression operation by is performed, and there is no fear that the main circuit is stopped. Therefore, as shown by the solid line in FIG. 6, the DC intermediate circuit voltage V _D avoids the possibility of abnormal rise even during the backward starting period.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention. This second embodiment circuit further includes a backward activation detector 41 and an AND element 42 in addition to the first embodiment circuit described above. It was done. When the AC electric vehicle starts up in the climbing direction on the inclined track, the AC electric vehicle moves backward due to the action of gravity if the torque from the induction motor 8 is insufficient even though the induction motor 8 is in the power running mode. When the AC electric vehicle moves backward, the induction motor 8 becomes a generator and regenerates electric power to the DC intermediate circuit. Therefore, even if the induction motor 8 is in the power running mode, the fact that it is in the power regeneration state is output as the reverse start mode signal A. ,
The reverse start detector 41 detects the presence or absence of the reverse start mode signal A. The logical product element 42 inputs the output signal of the suppression voltage setting device 32 and the output signal of the backward activation detector 41, calculates the logical product of them, and gives the calculation result to the suppression switch 17 via the logical sum device 33. I am trying.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention. The circuit of the second embodiment is different from that of the voltage suppressing resistor 1 in FIG.
8 is different in that a diode 51 is connected in parallel, and is the same in all other respects, and detailed description thereof will be omitted. In this third embodiment circuit, when the reverse starting mode is canceled and the AC electric vehicle starts to move forward,
Alternatively, when the DC intermediate circuit voltage is below the value set by the suppression voltage setting unit 31, the suppression switch 17 is turned off,
The current flowing in the voltage suppression resistor 18 is cut off. At this time, the energy stored in the inductance held by the voltage suppression resistor 18 circulates in the closed circuit formed by the diode 51 and the voltage suppression resistor 18 and disappears. Therefore, although not shown, it goes without saying that the present invention also includes a circuit in which the diode 51 is connected in parallel to the voltage suppression resistor 18 described in the circuit of the first embodiment described above with reference to FIG.

[0014]

According to the present invention, the overvoltage as the first voltage detecting means for stopping the main circuit by detecting that the DC intermediate circuit of the AC electric vehicle has reached the overvoltage (that is, the first set value). In addition to the detector, a suppression voltage detector is provided as a second voltage detection means for detecting an overvoltage (that is, a second set value) having a lower value than this, and when the suppression voltage detector operates or this suppression voltage detector operates. When the voltage detector and the backward start detector are activated, only the DC intermediate circuit voltage is lowered using the voltage suppression resistor without stopping the main circuit, so the inclined line is started in the climbing direction. Even when the AC electric vehicle is in the reverse start mode when starting, it is possible to smoothly start and move to the forward drive state without failing to start.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a conventional example of a control device for an AC electric vehicle.

5 is an operation waveform diagram showing an operation mode of an AC electric vehicle equipped with the conventional circuit shown in FIG.

FIG. 6 is an operation waveform diagram showing operation waveforms of various parts when the AC electric vehicle is reversely started.

[Explanation of symbols]

 3 Circuit Breaker 4 Transformer 7 Inverter 8 Induction Motor 11 Rectifier 16 DC Voltage Detector 17 Suppression Switch 18 Voltage Suppression Resistor 21 Overvoltage Setting Device 22 Overvoltage Detector as First Voltage Detection Means 23 Protection Signal Generation Circuit 31 Suppression Voltage Setting Device 32 Suppression voltage detector as second voltage detecting means 33 Logical sum element 41 Backward activation detector 42 Logical product element 51 Diode

Claims (3)

[Claims] 1. A rectifier for converting an alternating current supplied from an overhead wire via a circuit breaker into a direct current and outputting it to a direct current intermediate circuit, and a rectifier connected to this direct current intermediate circuit to convert the direct current into an alternating current of a desired voltage and frequency. An AC electric vehicle equipped with an inverter and an induction motor that drives the wheels by using the inverter as a power source detects that the voltage of the DC intermediate circuit exceeds a first set value, First voltage detecting means for issuing a trip command, a simultaneous off command to the switching elements forming the inverter, and an operation command to a resistance short-circuiting device for short-circuiting the positive electrode and the negative electrode of the DC intermediate circuit via a resistor; The control device for an AC electric vehicle, which is provided with, includes a second voltage detecting means for detecting that the DC intermediate circuit voltage has reached a second set value that is lower than the first set value. A controller for an AC electric vehicle detection means is equal to or emit the operation command to the resistor short-circuiting means if operation. 2. A rectifier for converting an alternating current supplied from an overhead wire through a circuit breaker into a direct current and outputting it to a direct current intermediate circuit, and a rectifier connected to the direct current intermediate circuit to convert the direct current into an alternating current of a desired voltage and frequency. An AC electric vehicle equipped with an inverter and an induction motor that drives the wheels by using the inverter as a power source detects that the voltage of the DC intermediate circuit exceeds a first set value, First voltage detecting means for issuing a trip command, a simultaneous off command to the switching elements forming the inverter, and an operation command to a resistance short-circuiting device for short-circuiting the positive electrode and the negative electrode of the DC intermediate circuit via a resistor; A control device for an AC electric vehicle, comprising: second voltage detection means for detecting that the DC intermediate circuit voltage has reached a second set value lower than the first set value; and the induction motor. The reverse start mode detecting means for detecting a state in which electric power is regenerated from the induction motor to the DC intermediate circuit despite the power running operation, the output signals of the second voltage detecting means and the reverse start mode detecting means. A control device for an AC electric vehicle, comprising: a logical product calculating means for calculating a logical product with an output signal, wherein the resistance short circuit means is operated by an output signal of the logical product calculating means. 3. A control device for an AC electric vehicle according to claim 1 or 2, wherein a diode having a polarity for blocking a DC intermediate circuit voltage is connected in parallel to a resistor forming the resistance short-circuit means. A control device for an AC electric vehicle characterized by being connected.