JP2015033180A - Vehicle controller and vehicle control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle controller and a vehicle control method capable of simply and accurately evaluating insulation resistance in a vehicle electrical system.SOLUTION: A vehicle controller includes: an AC current detector 123; and a pre-earth occurrence notification unit. The AC current detector 123 is electrically connected between an intermediate potential line 102, which connects a converter 10 to which AC power is input from outside and which converts the AC power to DC power and an inverter 11 to which the DC power is input and which supplies the AC power to a load, and an earth point B, and detects an AC current. The pre-earth occurrence notification unit compares the AC current detected by the AC current detector 123 with a predetermined AC current threshold set lower than an earth current detection threshold that is a current threshold for detecting occurrence of earth.

Description

  Embodiments described herein relate generally to a vehicle control device and a vehicle control method.

  Generally, in a vehicle control device, electric power is received from an overhead wire, converted into voltage / current necessary for driving the vehicle, and supplied to a motor. A power converter including a converter and an inverter is used for voltage / current conversion. This power conversion device may be provided with a current detector that detects a ground current in order to protect the device when a ground fault occurs in the device itself. Whether or not the power converter is operating normally by using the ground current value detected by the current detector, for example, by determining that a ground fault has occurred when the ground current value exceeds a predetermined threshold value. Judgment is made.

  In general, there is a case where an insulation resistance confirmation operation in the power conversion device is performed at the time of inspection of the vehicle. By carrying out such confirmation work, it is possible to prevent a ground fault accident in advance, or to identify the cause of the occurrence of a ground fault (for example, see Patent Document 1).

JP 2012-223020 A

However, as a measure to prevent ground faults, when conducting insulation resistance confirmation work in power converters, it is necessary to prepare equipment such as high voltage generators and to connect them. It took time and effort.
In addition, even if the insulation resistance is normal when the vehicle is inspected, the insulation resistance deteriorates during the actual operation of the vehicle, and a ground fault may occur. There is a problem that it is impossible to accurately evaluate whether or not is maintained.

  The problem to be solved by the present invention is to provide a vehicle control device and a vehicle control method capable of simply and accurately evaluating insulation resistance in an electric system of a vehicle.

  The vehicle control device of the embodiment includes an AC current detector and a ground fault occurrence notification unit. The AC current detector includes an intermediate potential line connecting a converter that inputs AC power from the outside and converts it into DC power, and an inverter that inputs the DC power and supplies AC power to a load. Electrically connected between them to detect alternating current. The ground fault occurrence notifying unit includes an alternating current detected by the alternating current detector, and a predetermined alternating current threshold set to a value lower than a ground fault current detection threshold that is a current threshold for detecting the occurrence of a ground fault. Make a comparison.

The figure which shows the whole structure of the vehicle control apparatus of 1st Embodiment. The figure which shows the function structure of the control part of 1st Embodiment. The figure which shows the processing flow of the control part of 1st Embodiment. The figure which shows the whole structure of the vehicle control apparatus of 2nd Embodiment. The figure which shows the function structure of the control part of 2nd Embodiment.

<First Embodiment>
The vehicle control apparatus according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating an overall configuration of a vehicle control device according to a first embodiment. In this figure, reference numeral 1 denotes a vehicle control device.
As shown in FIG. 1, the vehicle control device 1 inputs AC power from an overhead line 20 via a pantograph 21 and a main transformer 22. Moreover, the vehicle control apparatus 1 converts the input AC power into AC power composed of a predetermined voltage and current, and supplies the AC power to the motor 3 of the vehicle as a load.

First, the overall configuration of the vehicle control device 1 will be described with reference to FIG.
The vehicle control device 1 includes a converter 10, an inverter 11, a ground current detection circuit 12, a control unit 13, and a circuit breaker 14.
Converter 10 converts AC power input via main transformer 22 into DC power (DC voltage and DC current). Converter 10 applies a DC positive potential to positive potential line 100 and a DC negative potential to negative potential line 101, and outputs the result to inverter 11. An intermediate potential between a positive potential and a negative potential to be output is applied to the intermediate potential line 102.
The inverter 11 inputs the DC voltage / DC current generated by the converter 10 and supplies a predetermined AC voltage / AC current to the motor 3 as a load.
As shown in FIG. 1, the ground current detection circuit 12 is connected between the intermediate potential point A and the ground point B, and detects a current (ground current) flowing through the ground point B.
The control unit 13 executes various processes based on the ground current detected by the ground current detection circuit 12. For example, when a ground fault occurs, the control unit 13 detects an increase in the ground current detected by the ground current detection circuit 12 and outputs a command signal for opening the circuit breaker 14.
For the purpose of protecting the own device and various electric systems, the circuit breaker 14 opens the electrical connection and cuts off the power supply when the circuit breaker opening command signal is input from the control unit 13 when the ground fault occurs. .

Next, the configuration of the ground current detection circuit 12 will be described with reference to FIG.
The ground current detection circuit 12 includes a resistor 120, a capacitor 121, a ground fault current detector 122, and an alternating current detector 123.
As shown in FIG. 1, the ground fault current detector 122 is connected in parallel with the capacitor 121. Thereby, the ground fault current detector 122 mainly detects the direct current component of the ground current. Moreover, since the ground fault current detector 122 is used to detect a direct current (ground fault current) that flows when a ground fault occurs, it can detect a relatively large current value.
As shown in FIG. 1, the alternating current detector 123 is connected in series with a resistor 120, a capacitor 121, and a ground fault current detector 122. Thereby, the alternating current detector 123 detects a ground current including an alternating current component. The AC current detector 123 is a current that constantly flows during operation, and is intended to detect an AC component that is smaller than the ground fault current (high-frequency ripple based on stray capacitance described later). Can detect a minute current value.

  As described above, the ground current detection circuit 12 according to the present embodiment includes the ground fault current detector 122 capable of detecting a large current and the AC current detector 123 capable of detecting a minute current. As a result, the ground current detection circuit 12 has a function of detecting a ground fault current when a ground fault occurs and a function of detecting a minute alternating current component that constantly flows before the occurrence of the ground fault.

  The detection signal of each current component by the ground fault current detector 122 and the alternating current detector 123 is output to the control unit 13. Here, in order to acquire the current value of the AC component by the AC current detector 123 with high accuracy, the output of the AC current detector 123 is input to the control unit 13 via the smoothing circuit 15. The smoothing circuit 15 may be configured by a circuit combining a rectifier diode and a smoothing capacitor, for example.

FIG. 2 is a diagram illustrating a functional configuration of the control unit according to the first embodiment.
Next, the functional configuration of the control unit 13 will be described with reference to FIG.
As shown in FIG. 2, the control unit 13 includes an alternating current determination unit 130, a ground fault occurrence notification unit 131, a ground fault current determination unit 132, and an open command output unit 133.

The alternating current determination unit 130 detects a sign of the occurrence of a ground fault at a stage before the ground fault occurs.
Specifically, the alternating current determination unit 130 inputs a ground current value detected by the alternating current detector 123 and determines whether or not the ground current value exceeds a predetermined current threshold value α (alternating current threshold value). If it exceeds, a predetermined ground fault occurrence determination signal is output to the pre-ground fault occurrence notification unit 131. As described above, the AC current detector 123 detects a minute AC component (high-frequency ripple) that constantly flows as a ground current.
Further, the current threshold value α is set to a value lower than a current threshold value β (described later) used for determining the occurrence of a ground fault described later.
As a specific configuration of the AC current determination unit 130, for example, the AC current determination unit 130 includes an A / D (Analog / Digital) conversion unit. The alternating current determination unit 130 takes in a current detection signal (analog signal) detected by the alternating current detector 123 and input via the smoothing circuit 15 as sampling data (digital signal). Then, the alternating current determination unit 130 performs a determination process as to whether or not the numerical value indicated by the acquired sampling data exceeds the current threshold value α stored in advance.

When the ground fault occurrence notification unit 131 receives the ground fault occurrence determination signal, a ground fault occurrence for notifying the operator or the outside that the AC component of the ground current is increasing as a sign of the occurrence of the ground fault. Outputs a previous notification signal. This notification signal before the occurrence of a ground fault is output to, for example, a warning lamp, a buzzer sound output device, etc., and the operator is notified that the AC component is increasing with the lighting of the warning lamp or a buzzer sound. Thus, the operator can recognize that a ground fault can occur in any of the electric systems at a stage before the ground fault occurs.
It will be described later that an increase in the AC component of the ground current can be regarded as a sign of occurrence of a ground fault.

The ground fault current determination unit 132 detects the occurrence of a ground fault when a ground fault actually occurs.
Specifically, the ground fault current determination unit 132 inputs the ground current value detected by the ground fault current detector 122, and whether or not the ground current value exceeds the current threshold β (ground fault current detection threshold). Is output, a predetermined ground fault occurrence determination signal is output to the opening command output unit 133. As described above, the ground fault current detector 122 detects a direct current (ground fault current) that flows when a ground fault actually occurs as a ground current. The current threshold β is set so that the circuit breaker 14 is opened upon detection of the ground fault current.
The specific configuration of the ground fault current determination unit 132 includes, for example, an A / D conversion unit similar to the AC current determination unit 130, and captures the current detection signal detected by the ground fault current detector 122 as sampling data. It is good also as what performs a determination process.

  When the ground fault occurrence determination signal is input, the opening command output unit 133 outputs a circuit breaker opening command signal toward the circuit breaker 14. When the breaker open command signal is input, the breaker 14 opens itself and shuts off the electrical system from the overhead line 20 as a power supply source. Thereby, when the ground fault occurs, the vehicle control device 1 and other electric systems are protected.

FIG. 3 is a diagram illustrating a processing flow of the control unit of the first embodiment.
Next, the processing flow of the control unit 13 will be described in order with reference to FIG.
First, power is turned on to the vehicle control device 1 and the control unit 13 (step S10). When the power is turned on, power supply from the overhead wire 20 is started simultaneously, the converter 10 and the inverter 11 start operating, and the motor 3 is driven.
When the motor 3 starts driving, the AC current determination unit 130 and the ground fault current determination unit 132 immediately input the ground current via the ground fault current detector 122 and the AC current detector 123 and acquire the current value. (Step S11).
Next, the AC current determination unit 130 determines whether or not the acquired ground current value (current value mainly including a minute AC component) exceeds the current threshold value α (step S12).
When it is determined that the ground current value acquired here exceeds the current threshold value α (step S12: YES), the alternating current determination unit 130 outputs a determination signal before the occurrence of a ground fault to the notification unit 131 before the occurrence of a ground fault. . Then, the ground fault occurrence notification unit 131 outputs the ground fault occurrence notification signal to a warning lamp, a buzzer sound output device, or the like (step S13). Thereby, the operator can recognize that the alternating current component which flows constantly is increasing as a sign of the occurrence of the ground fault.
On the other hand, when AC current determination unit 130 determines that the acquired ground current value is equal to or less than current threshold value α (step S12: NO), it does not output the determination signal before the occurrence of ground fault.

Next, the ground fault current determination unit 132 determines whether or not the acquired ground current value exceeds the current threshold value β (step S14).
When it is determined that the ground current value acquired here exceeds the current threshold β (step S14: YES), the ground fault current determination unit 132 outputs a ground fault occurrence determination signal to the open command output unit 133. Then, the opening command output unit 133 outputs a circuit breaker opening command signal to the circuit breaker 14 assuming that a ground fault has occurred (step S15). Thereby, since the electric power supply to an electric system is interrupted when a ground fault occurs, damage to various electric systems due to a ground fault can be prevented.
On the other hand, if the ground fault current determination unit 132 determines that the acquired ground current value is equal to or less than the current threshold value β (step S12: NO), the ground fault occurrence determination signal is output assuming that no ground fault has occurred. Do not output. Thereafter, the control unit 13 returns to step S11 and continuously repeats the subsequent processes.

The processing flow of the control unit 13 described above is an example, and the processing flow performed by the control unit 13 is not limited to the processing flow illustrated in FIG. For example, the control unit 13 can exchange the order of the determination of the ground current by the alternating current determination unit 130 and the determination of the ground current by the ground fault current determination unit 132, or can simultaneously execute these. .
Similarly, the processing flow of the control unit 13 can be changed as long as the purpose of each process performed by the control unit 13 can be achieved.

Here, a point that can be recognized as a sign of occurrence of a ground fault by an increase in a minute AC component detected by the AC current determination unit 130 will be described.
As shown in FIG. 1, the converter 10 performs a process of inputting AC power from the overhead line 20 and converting it into DC voltage / DC current. Further, the inverter 11 generates AC power for supplying the DC voltage / DC current to the motor 3. Such operations of the converter 10 and the inverter 11 generate an AC component as so-called “high-frequency ripple”. This AC component propagates to the ground current detection circuit 12 and the ground point B through stray capacitance existing in the entire electric system of the vehicle.
Here, the stray capacitance exists not a little depending on the arrangement of the electrical wiring and the housing frame. The fact that a minute AC component propagates to the ground point B via this stray capacitance does not cause a problem in driving the vehicle (motor 3). However, when this AC component increases, it is presumed that stray capacitance increases in any part of the electric system of the vehicle. The increase in stray capacitance is presumed that the electrical spacing is narrowed at a certain part between the electrical wirings. Therefore, the insulation resistance is lowered at that part, and there is a probability that a ground fault will occur. Expected to be higher.
For example, as a cause of occurrence of a ground fault, short-circuiting due to accumulation of various wirings (100, 101, 102, etc.) and foreign matters (dust etc.) in the motor 3 can be mentioned. In this case, the vehicular control apparatus 1 according to the present embodiment monitors the AC component (high frequency ripple) of the ground current generated by driving the own apparatus, so that stray capacitance is generated in any of the electric systems due to the accumulation of foreign matters. You can identify the increase.
With such a mechanism, the vehicle control device 1 can identify an increase in stray capacitance as a sign of occurrence of a ground fault.

According to the vehicle control apparatus according to the first embodiment described above, the magnitude of the minute alternating current (high-frequency ripple) detected by the alternating current detector 123 is detected as the insulation resistance of the electric system during normal operation of the vehicle. Can be evaluated. Therefore, the operator can evaluate the insulation resistance of the electric system in real time during operation of the vehicle, and can accurately identify whether there is no problem in the insulation resistance.
In addition, the operator who receives the notification by turning on the warning lamp or the buzzer sound identifies the portion where the insulation resistance is lowered and implements the improvement measures. Therefore, the vehicle control device 1 can prevent the occurrence of a ground fault, and can reduce the burden of a recovery process from a ground fault.
Further, since it is only necessary to newly provide a current detector capable of detecting a minute current and its peripheral circuit, the configuration of the entire vehicle control device can be simplified.

  As a modification of the vehicle control device 1 according to the first embodiment, in the configuration of the ground current detection circuit 12, a single current detector includes a ground fault current detector 122 and an AC current detector 123. Both functions may be provided. That is, by using a current detector that can detect a minute alternating current along with a ground fault current, the number of circuit components can be reduced and the circuit scale can be reduced.

<Second Embodiment>
Hereinafter, the vehicle control apparatus according to the second embodiment will be described with reference to the drawings.
FIG. 4 is a diagram illustrating an overall configuration of the vehicle control device according to the second embodiment. In this figure, reference numeral 1A denotes a vehicle control device. In addition, about the structure same as the vehicle control apparatus 1 which concerns on 1st Embodiment among the structures of 1 A of vehicle control apparatuses which concern on this embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

The vehicle control apparatus 1A according to the present embodiment is the first implementation in that the ground fault current detector 122 is not provided, and the AC current detector 123A is provided with a demagnetization removing unit 1230 having a new functional configuration. Different from form.
Hereinafter, the function of the AC current detector 123A will be described.
The AC current detector 123A includes a demagnetization removing unit 1230 that removes a demagnetization that may occur when a ground fault current is input based on a reset signal input from the outside. Here, the AC current detector 123A detects a current value by reading a magnetic field generated according to a current to be detected using a magnetic sensor, like a general current detector.
Here, the alternating current detector 123A is customized so that the magnetic sensor can detect a minute change in magnetism in order to detect a minute alternating current that constantly flows. Then, when a large direct current such as a ground fault current is input to the alternating current detector 123A, the magnetic sensor is demagnetized, and thereafter, a phenomenon in which accurate current detection cannot be performed occurs.
In order to solve this problem, the ground current detection circuit 12A according to the present embodiment includes a demagnetization removing unit 1230 capable of performing a process (demagnetization) to remove this demagnetization as a current detector. The demagnetization removing unit 1230 performs a process of removing the demagnetization by applying an alternating current, for example, as a general demagnetization process.

  In the present embodiment, as shown in FIG. 4, a part of the current detection signal of the AC current detector 123 </ b> A is input to the control unit 13 </ b> A via the smoothing circuit 15. Thereby, the control unit 13A can input the current detection signal of the AC current detector 123A separately for ground fault detection and for AC current detection (via the smoothing circuit 15).

FIG. 5 is a diagram illustrating a functional configuration of a control unit according to the second embodiment. Among the configurations of the control unit 13A according to the present embodiment, the same configurations as those of the control unit 13 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 5, the control unit 13A according to the present embodiment has a configuration in which the detection current from the AC current detector 123A is input to the AC current determination unit 130 and the ground fault current determination unit 132. The control unit 13A is different from the control unit 13 according to the first embodiment in that the control unit 13A includes a reset signal output unit 134.

  The reset signal output unit 134 receives a signal (for example, a circuit breaker opening command signal) indicating that a ground fault has occurred, and outputs a predetermined reset signal to the demagnetization removing unit 1230 of the AC current detector 123A. As a result, even when a demagnetization occurs in the AC current detector 123 when a ground fault occurs, a demagnetization process that automatically removes the demagnetization is performed. Therefore, the AC current detector 123A can be used as it is without requiring adjustment work by an operator.

In the above description, the reset signal output unit 134 has been described as receiving a circuit breaker opening command signal indicating that a ground fault has occurred and outputting a reset signal to the demagnetization removing unit 1230. A modification of the embodiment is not limited to this method.
For example, the reset signal output unit 134 may output a reset signal after inputting a signal indicating the occurrence of a ground fault and then opening a predetermined period. By doing in this way, the demagnetization removal part 1230 can implement a demagnetization process, after the electric power supply is interrupted | blocked by the circuit breaker 14 reliably.

  According to the vehicle control apparatus according to the second embodiment, even if a ground fault occurs and a large direct current is input, the alternating current detector 123A can automatically return. Therefore, it is possible to reduce the burden of return processing after the occurrence of the ground fault.

  According to the vehicle control device of at least one embodiment described above, it is possible to simply and accurately evaluate the insulation resistance in the electric system of the vehicle by detecting the AC component of the ground current generated during normal operation.

Note that the circuit configurations of the ground current detection circuits 12 and 12A of the above-described embodiment are not limited to the configurations shown in FIGS. For example, according to FIGS. 1 and 4, the AC current detectors 123 and 123 </ b> A are connected to the ground point B. However, the AC current detectors 123 and 123A according to the modification of each embodiment may be connected to the intermediate potential point A, for example.
In addition, the circuit configuration of the ground current detection circuits 12 and 12A can be changed as long as the object can be achieved.

In addition, the aspect which has a computer system inside may be sufficient as the above-mentioned control parts 13 and 13A. Each process of the control units 13 and 13A described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing the program. Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM (Compact Disk Read Only Memory), a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.
In addition, the control units 13 and 13A may be configured such that the above-described functional units are distributed and provided in a plurality of devices connected via a network.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof, as long as they are included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1, 1A ... Vehicle control apparatus 10 ... Converter 11 ... Inverter 12, 12A ... Ground current detection circuit 120 ... Resistance 121 ... Capacitor 122 ... Ground fault current detector 123 , 123A ... AC current detector 1230 ... Demagnetization removing unit 13, 13A ... Control unit 130 ... AC current determining unit 131 ... Notification unit 132 before ground fault occurrence ... Ground fault current Determining unit 133 ... Opening command output unit 134 ... Reset signal output unit 14 ... Circuit breaker 15 ... Smoothing circuit 20 ... Overhead wire 21 ... Pantograph 22 ... Main transformer 3 ... motor

Claims (7)

An electrical connection between an intermediate potential line connecting the converter that inputs AC power from the outside and converts it into DC power, and an inverter that inputs the DC power and supplies AC power to a load, and a ground point, An alternating current detector for detecting alternating current;
Before the occurrence of a ground fault, the AC current detected by the AC current detector is compared with a predetermined AC current threshold set to a value lower than a ground fault current detection threshold that is a current threshold for detecting the occurrence of a ground fault. A notification unit;
A vehicle control device comprising: The alternating current detector is
The vehicle control device according to claim 1, wherein at least a capacitor is connected in series between the intermediate potential line and the grounding point. The ground fault current detector connected between the intermediate potential line and the grounding point and capable of detecting a current larger than the alternating current detector is further provided. Vehicle control device. The alternating current detector is
The processing for removing the bias magnetism generated based on the input current when a predetermined reset signal from the outside is input is performed. The method according to any one of claims 1 to 3, wherein: Vehicle control device. The converter inputs AC power from an overhead line via a pantograph,
The vehicle control device according to any one of claims 1 to 4, wherein the inverter inputs the DC power and supplies AC power to a motor of the vehicle. The ground fault occurrence notification unit
The vehicle control device according to any one of claims 1 to 5, wherein when the alternating current exceeds the alternating current threshold value, notification is made to the outside. An AC current detector includes an intermediate potential line connecting a converter that inputs AC power from the outside and converts the converter into DC power, and an inverter that inputs the DC power and supplies AC power to a load. Is electrically connected between and detects alternating current,
The notification unit before occurrence of a ground fault is an alternating current detected by the alternating current detector, and a predetermined alternating current threshold set to a value lower than a ground fault current detection threshold that is a current threshold for detecting the occurrence of a ground fault. A vehicle control method that compares

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