JP2001119960A - Emergency shut-off method and device for vehicle power supply circuit and voltage converter for vehicle - Google Patents

Abstract

(57) Abstract: In a vehicle power supply circuit, the power supply circuit is urgently cut off without specially providing a dedicated switch means. SOLUTION: A DC-DC converter 20, which is a voltage converter including a switch element for an inverter, is interposed in a power supply circuit from a vehicle-mounted power supply 10 to a load 12. In an emergency, the power supply is stopped urgently by forcibly turning off the switch element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit mounted on a vehicle, when an abnormality such as a short circuit to ground or a disconnection is actually generated in the circuit, or in an emergency such as a collision of the vehicle. The present invention relates to a method and apparatus for reliably protecting the power supply circuit, and a vehicle voltage converter having the protection function.

[0002]

2. Description of the Related Art Generally, in electric circuits for automobiles and the like,
Fuses and fusible links are commonly used as a means for immediately breaking a circuit when an overload current or a short-circuit current occurs. These fuses and fusible links have a fusible conductor inside the container, and have a basic structure in which connection terminals are led out of the container. Is introduced into the circuit.

[0003]

The fuse or fusible link blows out only when an overcurrent occurs,
Since the circuit is interrupted, it is impossible to cope with other emergencies. For example, the protection function cannot be exhibited in the following cases.

A) As a mode in which an electric wire is short-circuited to ground,
There is so-called chattering, in which the electric wire intermittently contacts the ground due to vibration of the vehicle or the like. Here, if the supply voltage of the circuit is high (for example, 20 V or more), an arc may be generated due to the chattering. Therefore, it is preferable to stop the power supply forcibly. However, the short-circuit due to the chattering has a smaller increase in current than a normal short-circuit in which the electric wire is continuously in contact with the ground, and therefore, there is a high possibility that the fuse will not be blown.

[0005] B) When a part of a plurality of electric wires constituting a power supply cable is broken, current concentrates on the remaining unbroken wires, and the wires may be overheated. However, even if such a disconnection occurs, the fuse does not blow because the sum of the currents flowing through the wires does not change from that before the disconnection.

C) For example, in the event of a vehicle collision, it is highly probable that an abnormality will occur in the circuit. Therefore, in this case, the power supply is forcibly stopped regardless of whether a short circuit or disconnection actually occurs. Is more preferable for safety. However, the fuse can be blown only when an overcurrent occurs, so that emergency cutoff cannot be performed at an appropriate timing.

As a means for interrupting the circuit even in an emergency as exemplified above, a relay switch may be interposed in the circuit to turn off the relay switch in an emergency. However, providing a special relay switch only for the purpose of emergency shutoff is not preferable from the viewpoint of simplification of the circuit and cost reduction. In addition, when the circuit is short-circuited, the current flowing through the switch becomes very large, so that a switch having a considerably large contact capacity must be used.

On the other hand, during normal power supply, the relay contacts must be securely closed, but the contacts may open intermittently when subjected to a large external force due to vehicle vibration or the like. In order to maintain the closed state of the contact against such external force, the configuration is inevitably large.

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to appropriately cut off a circuit in a vehicular power supply circuit in an emergency without specially providing a dedicated circuit breaking means.

[0010]

In recent years, the number of loads (electrical components) mounted on vehicles has been steadily increasing, and the operating voltage of each load is also diversifying. On the other hand, since the output voltage of the vehicle-mounted power supply is determined, it is necessary to interpose a voltage converter in the circuit in order to properly supply power to the load from the power supply. In addition, the on-vehicle power supply is generally a DC power supply (combination of an alternator and an AC-DC converter or a DC battery). To convert the output DC voltage to another voltage by the voltage converter, A switch element for an inverter that intermittently turns on and off a DC voltage to once generate an AC voltage is required.

The present invention has been made in view of the necessity of such a voltage converter. In a vehicle power supply circuit for supplying power from a vehicle-mounted DC power supply to a load, a vehicle power supply circuit is provided between the DC power supply and the load. A voltage converter including a switch element for generating an AC voltage by turning on and off the output voltage of the DC power supply, and forcibly turning off the switch element of the voltage converter in an emergency to load the DC power supply from the DC power supply. A power supply circuit for emergency stop of the vehicle power supply circuit for stopping the power supply, and a voltage including a switch element interposed between the DC power supply and a load, for turning on and off an output voltage of the DC power supply to generate an AC voltage. And a protection control means for forcibly turning off the switching element of the voltage converter to stop power supply from the DC power supply to the load in an emergency. It is a cross-sectional device.

As described above, the circuit is forcibly cut off in an emergency by using the switching element of the voltage converter, so that the power supply circuit can be properly protected with a simple and inexpensive configuration without adding any special switch means. Can be.

Here, the "emergency" includes, for example, a time when a short circuit or a break is detected in a power supply wire. In such a case, overheating of the electric wires and other parts is prevented by forcibly interrupting the circuit. Further, in addition to the case where the circuit abnormality is actually detected, the emergency shutdown may be executed when a phenomenon causing the circuit abnormality occurs, for example, at the time of a vehicle collision.

In the former case, abnormality detecting means for detecting the occurrence of an abnormality in the circuit (for example, short-circuit detecting means for detecting a short-circuit of an electric wire provided in the power supply circuit, or detecting disconnection of an electric wire provided in the power supply circuit) And the protection control means may be configured to forcibly turn off the switch element of the voltage converter when an abnormality is detected by the abnormality detection means.

The protection control means may be provided separately from the outside of the voltage converter. However, the protection control means is provided with control means for controlling the operation of the switch element at the time of power supply to the voltage converter. If the control means is also used as the protection control means, the configuration can be further simplified. Also,
Since a circuit protection function can be added to the voltage converter itself in advance,
Wiring work is also easy.

According to the present invention, there is provided a vehicle voltage converter provided with the circuit protection function, that is, a switch element for turning on and off an output voltage of the DC power supply to generate an AC voltage, and a switch element generated by the switch element. A transformer for transforming an AC voltage, and controlling the operation of the switch element at the time of power supply, and forcibly turning off the switch element of the voltage converter when a circuit abnormality signal is input to load the load from the DC power supply. And a protection control means for stopping power supply to the power converter.

Further, the vehicle voltage converter includes a current detector for detecting at least one of a current input to the voltage converter and a current output from the voltage converter, and a circuit abnormality based on the detected current. A determination unit for determining the presence or absence of a failure and generating a circuit abnormality signal when an abnormality is determined, a circuit abnormality determination function can be added to the voltage converter. As a result, wiring for the circuit configuration can be achieved. The structure and wiring work are further simplified.

[0018]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG.

The power supply circuit shown in FIG. 1 includes a vehicle-mounted DC power supply (for example, a battery) 10 whose negative terminal is connected to the ground and whose positive terminal is a DC-DC converter which is a voltage converter via a cable 14A. 20 input units. The output of the DC-DC converter 20 is connected to one terminal of the load 12 via a cable 14B, and the other terminal of the load 12 is connected to ground.

FIG. 1 is a simplified representation of a power supply circuit, and elements such as a fuse, a relay, and an electric connection box can be freely provided in the middle of the cables 14A and 14B. Further, a plurality of loads 12 are connected to a common D
You may connect to C-DC converter 20.

The power supply circuit is characterized in that a portion of the cable 14A close to the power source and a load 1 of the cable 14B are connected.
The current sensors 18A and 18B for detecting the level of the current flowing through the relevant portions are provided in the portions close to 2.

On the other hand, the DC-DC converter 20
As shown in FIG. 2, a high-frequency transformer (transformer) 21, a power switch element 22, a drive circuit 24, a control circuit 2
6. A rectifier circuit 28 and a smoothing circuit 30 are built in a housing, and an input connector Ci and an output connector Co are provided outside the housing.

The high-frequency transformer 21 includes a primary coil 21
a and the secondary side coil 21b. One end of the primary coil 21a is connected to the cable 14A via the power switch element 22 and the input connector Ci,
The other end is connected to ground. One end of the secondary coil 21b is connected to the cable 14B via the rectifier circuit 28, the smoothing circuit 30, and the output connector 14B, and the other end is connected to the ground.

The power switch element 22 receives an input signal from the drive circuit 24, and is switched between an ON state in which the current flows between the cable 14A and the primary coil 21a and an OFF state in which the current is interrupted. As the power switch element 22, in addition to the illustrated MOSFET, IG
BT and other transistors are suitable, but any type may be used as long as it has a switching function.

The control circuit 26 outputs a control signal to the drive circuit 24 and controls on / off of the power switch element 22. Specifically, at the time of normal power supply receiving a drive command signal from the outside, the power switch element 2
2 is turned on and off at a high frequency to generate a pulse voltage (AC voltage) in the primary coil 21a of the high frequency transformer 21. Thereby, the secondary coil 21b of the transformer 21
Generates a transformed AC voltage. This AC voltage is converted to a DC voltage by the rectifier circuit 28 and the smoothing circuit 30 and supplied to the load 12 via the cable 14B.

The control circuit 26 monitors the output voltage from the smoothing circuit 30 and controls the on / off frequency and the pulse width so that a constant voltage (for example, a DC 14 V voltage) is stably obtained.

Further, the DC-DC converter 20 is characterized in that current detection circuits (current detection units) 32A and 32B and filter / comparison circuits (judgment units) 34A and 34B are incorporated in the housing, Are provided with sensor connectors Cb and Cr,
Current detection signals from the power supply side current sensor 18A and the load side current sensor 18B are input to these connectors Cb and Cr, respectively.

The current detection circuit 32A is connected to the cable 14
The current detection circuit 32B detects the level of the current input from A through the input connector Ci, and the current detection circuit 32B detects the level of the current output from the output connector Co to the cable 14B. These current detection circuits 32
For example, those which measure a voltage drop due to a constant resistance can be applied to the current sensors A and 32B and the current sensors 18A and 18B.

The filter / comparison circuit 34A takes in the low / medium frequency components of the current detection signal input from the power supply side current sensor 18A and the low / medium frequency components of the current detection signal input from the current detection circuit 32A. Calculates the difference ΔIa between the current levels of the two signals, and inputs a circuit abnormality signal to the control circuit 26 when the current level difference ΔIa exceeds a preset allowable current difference. Similarly, the filter / comparison circuit 34B includes the load-side current sensor 1
The low and medium frequency components of the current detection signal input from the current detection circuit 32B and the low and medium frequency components of the current detection signal input from the current detection circuit 32B are taken in, and the difference ΔIb between the current levels applied to both signals is calculated. At the same time, when the current level difference ΔIb exceeds a preset allowable current difference, a circuit abnormality signal is input to the control circuit 26.

The control circuit 26 controls the filter
When a circuit abnormality signal is input from at least one of the comparison circuits 34A and 34B, the driving of the power switch element 22 by the drive circuit 24 is forcibly stopped irrespective of the ON / OFF command signal, that is, the power switch element 22 is forcibly stopped. Is switched off.
That is, in this embodiment, the control circuit 26 is also used as protection control means according to the present invention.

In this embodiment, the drive circuit 24, the control circuit 26, and the filter / comparison circuit 34
A and 34B are mounted on the same circuit board 36, and the entire circuit board 36 is incorporated in the DC-DC converter 20.

Next, the operation of this circuit will be described.

First, the cables 14A and 14B
The normal state in which is not short-circuited to the ground will be described.

In this state, the power supply 10
8A through the current detection circuit 32A in the DC-DC converter 20.
1 flows into the primary coil 21a. Therefore, the current level detected by the current sensor 18A is equal to the current level detected by the current detection circuit 32A, and the current difference hardly occurs. Therefore, a circuit abnormality signal is output from the filter / comparison circuit 34A to the control circuit 26. Never.

When a current flows through the primary coil 21a, a current is generated in the secondary coil 21b by electromagnetic induction caused by the current. This current is supplied to DC through the current detection circuit 32B.
-After being output from the DC converter 20, all of it flows into the load 12 through the current sensor 18B. Therefore, the current level detected by the current sensor 18B is equal to the current level detected by the current detection circuit 32B, and the current difference hardly occurs.
Does not output a circuit abnormality signal to the control circuit 26.

That is, since no circuit abnormality signal is input to the control circuit 26, the circuit 26 outputs an appropriate control signal to the drive circuit 24 to
2 drive control, that is, control for turning on / off the power switch element 22 so as to obtain a stable secondary voltage. As a result, power having an appropriate voltage is supplied to the load 12.

On the other hand, for example, the covering of the middle part of the cable 14B is broken and the conductor part is partially exposed, and the conductor part intermittently comes into contact with the ground part of the vehicle due to vibrations during running of the vehicle. When chattering occurs (two-dot chain line L1 in FIG. 1), the leakage current Id flows from the cable 14 to the ground side every time the intermittent short circuit occurs, so that the detection current level of the current detection circuit 32B in the DC-DC converter 20 is detected. A difference ΔI occurs between I1 and the detected current level I2 of the load-side current sensor 18B. If the difference ΔI exceeds the allowable current difference in advance, the filter / comparison circuit 34B
Input circuit abnormal signal to Control circuit 26 receiving this
Corresponds to the drive circuit 24 regardless of the current ON / OFF command.
, The driving of the power switch element 22 is stopped, the element 22 is forcibly turned off, and the power supply to the cable 14B is forcibly cut off.

When the chattering occurs in the cable 14A, the amount of leakage current between the detected current level of the power supply side current sensor 18A and the detected current level of the current detection circuit 32A in the DC-DC converter 20 is reduced. When the difference exceeds the allowable current difference, a circuit abnormality signal is input from the filter / comparison circuit 34A to the control circuit 26. Therefore, also at the time of chattering of the cable 14A, similarly to the chattering of the cable 14B, the driving of the power switch element 22 is forcibly stopped, and the energization of the cable 14A is forcibly cut off.

Therefore, the allowable current difference (threshold) is
For example, by setting as a value corresponding to the minimum value of the current difference ΔI that can occur due to the chattering, it is possible to automatically cut off the energization at the time of leakage due to the chattering, and to quickly generate an arc due to the chattering. It is possible to prevent it.

In addition, since this forced cut-off utilizes the power switch element 22 built in the DC-DC converter 20 interposed between the power supply 10 and the load 12, there is no need to introduce any special switch means. Appropriate circuit protection can be achieved with a simple and inexpensive structure.

A second embodiment of the present invention will be described with reference to FIGS.

In the first embodiment, the power supply is forcibly cut off when a short circuit such as chattering occurs, but in the second embodiment, the power supply side cable 14A and the load side cable 14B are connected. The interruption of a part of the constituent electric wire is detected, and the power supply is interrupted when the interruption is detected. The specific configuration for that is as follows.

1) A plurality of electric wires constituting the cables 14A and 14B are respectively connected to a first group G1 and a second group G2.
And is divided into

The specific method of dividing this group is as follows.
It can be set freely according to the structure of A (14B).
For example, as shown in FIG. 4A, in a cable 14A (14B) in which four insulated wires in which an insulation coating 16 is provided around a conductor 15 are accommodated in a sheath 19, two of the sheaths are covered. The electric wires may be a first group G1, and the remaining two covered electric wires may be a second group G2. Further, as shown in FIG. 3B, the conductors 15 constituting the respective groups G1 and G2 may be covered with an insulator 17 so that the respective groups G1 and G2 may be configured as mutually independent cables.

In the latter case as well, it is preferable that the conductors 15 be individually insulated and coated as much as possible to ensure the independence of the current flowing through each conductor 15. In addition, each group G1, G2
Also, when these are cabled, by covering them with the sheath 19 as shown in FIG. 4B, the risk of disconnection is reduced and the handling of the wiring is facilitated.

In this embodiment, each group G
It is assumed that the total conductor cross-sectional area and the wire length of each group are set so that the electrical resistances of the first and the second G2 are equal to each other.

2) The DC-DC converter 20 includes
1 and a current sensor (current detection unit) for individually detecting the levels of the currents i1 and i2 flowing through G2. Specifically, as shown in FIG. 5, a conductor for connecting the power switch element 22 and the cable 14A in the DC-DC converter 20 is connected to the first group G1 of the cable 14A on the way. It branches into a conductor and a conductor connected to the second group G2, and current sensors 41A and 42A are provided in each of the branch conductors. Similarly, DC-D
Smoothing circuit 30 and cable 1 in C converter 20
Also, the conductor for connecting to the first group G1 of the cable 14B and the conductor to be connected to the second group G2 of the cable 14B are branched on the way. 41B and 42B are provided.

3) DC-DC converter 20 shown in FIG.
Then, as shown in FIG.
Drive circuit 24 and control circuit 2 on circuit board 36 inside
6, filter / comparison circuits 34A and 34B are mounted. However, it differs from the one shown in FIG. 2 in the following points.

The filter / comparison circuit 34A includes a first group G1
The low / medium frequency component of the current detection signal input from the current sensor 41A on the side and the low / medium frequency component of the current detection signal input from the current sensor 42A on the second group G2 side are fetched and applied to both signals. A difference Δia between the current levels is calculated, and when the current level difference Δia exceeds a preset allowable current difference, a circuit abnormality signal is sent to the control circuit 2.
Enter 6 Similarly, the filter / comparison circuit 34B
The low / medium frequency component of the current detection signal input from the first group G1 side current sensor 41B and the second group G2 side current sensor 4
The difference Δib between current levels applied to both signals by taking in the low and middle frequency components of the current detection signal input from 2B
And if the current level difference Δib exceeds a preset allowable current difference, a circuit abnormality signal is input to the control circuit 26.

Then, as in the first embodiment, the control circuit 26 includes the filter / comparison circuits 34A, 34B
When the circuit abnormality signal is input from at least one of the drive circuit 24 and the drive circuit 24 regardless of the ON / OFF command signal.
Is forcibly stopped, that is, the power switch element 22 is forcibly switched off. That is, also in this embodiment, the control circuit 26 is also used as protection control means according to the present invention.

Next, the operation of this circuit will be described.

First, a description will be given of a normal state in which any of the conductors included in the cables 14A and 14B has no disconnection.

In this state, since the electric resistances of the two groups G1 and G2 in the cable 14A are equal to each other, mutually equal currents flow through these groups G1 and G2. That is,
Current level i detected by both current sensors 41A and 42A
1, i2 are equal, and their difference ΔIA is zero. Therefore, the filter / comparison circuit 34A does not output a circuit abnormality signal. Similarly, both groups G in the cable 14B
1 and G2, the currents are equal to each other.
Since the current levels i1 and i2 detected by B and 42B are equal, the filter / comparison circuit 34B also does not output a circuit abnormality signal.

That is, since no circuit abnormality signal is input to the control circuit 26, the circuit 26 outputs an appropriate control signal to the drive circuit 24 to
2 drive control, that is, control for turning on / off the power switch element 22 so as to obtain a stable secondary voltage. As a result, power having an appropriate voltage is supplied to the load 12.

On the other hand, for example, when a part of the conductor forming the first group G1 of the cable 14A (or the cable 14B) is broken, the electric resistance of the entire first group G1 is reduced by that amount. The electric resistance of the second group G2 is larger than the electric resistance of the second group G2, and the current flowing through the first group G1 is smaller than the current flowing through the second group G2. That is, both groups G1, G2
Current balance is lost. Thereby, the current sensor 41
A difference Δia occurs between the detected current level i1 of A and the detected current level i2 of the current sensor 42A (or a difference Δib between the detected current level i1 of the current sensor 41B and the detected current level i2 of the current sensor 42B). Occurs.)

The filter / comparison circuit 34 which has calculated this difference
A (or the filter / comparison circuit 34B) inputs the circuit abnormality signal to the control circuit 26, and upon receiving this input, the control circuit 26 drives the power switch element 22 by the drive circuit 24 regardless of the current ON / OFF command. Is forcibly stopped.

Therefore, by setting the above-mentioned threshold value as a value corresponding to, for example, the minimum value of the current difference ΔI that can be caused by the disconnection of one conductor, the power supply is automatically cut off when the conductor is disconnected. It is possible to prevent the remaining conductors from being overheated due to such partial disconnection of the conductors in advance.

That is, in this embodiment, by monitoring not the absolute value of the current flowing through the entire circuit but the relative relationship between the current flowing through the first group and the current flowing through the second group, an appropriate disconnection can be achieved. Detection and overheating prevention can be realized.

Furthermore, as in the first embodiment, the circuit emergency shutoff at the time of disconnection occurs using the power switch element 22 built in the DC-DC converter 20 interposed between the power supply 10 and the load 12. Therefore, there is no need to introduce any special switch means, and appropriate circuit protection can be achieved with a simple and inexpensive structure.

In addition, the present invention can take the following embodiments, for example.

In the first and second embodiments, the circuit is cut off when a short circuit is detected and a disconnection is detected. However, both functions of short-circuit detection and disconnection detection are added. Alternatively, the circuit may be interrupted when at least one of them is detected. Further, the term “emergency” in the present invention is not limited to when an abnormality actually occurs in a circuit. For example, when a phenomenon that causes the short circuit or disconnection occurs, the power supply may be cut off regardless of the actual short circuit or disconnection at the time of a vehicle collision, for example. In this case, for example, an airbag operation signal may be taken in as a circuit abnormality detection signal.

The “voltage converter” according to the present invention is a DC converter.
-Not limited to DC converters. For example, when a DC-AC inverter is interposed between a DC power supply and an AC load, a switch element of the inverter can be used for forcible shutoff.

In the illustrated example, a cable 14A from the power supply 10 to the DC-DC converter 20 as a voltage converter is provided.
Although the monitoring of the cable 14B from the DC-DC converter 20 to the load 12 for the presence or absence of an abnormality such as a short circuit or a disconnection has been described, for example, when one of the cables 14A and 14B is short and the abnormality hardly occurs, When the converter is directly connected to a power supply or a load, for example, it is possible to appropriately omit the abnormality detection for any of the cables 14A and 14B.

In the circuit examples shown in FIGS. 2 and 5, the filter / comparison circuits 34A and 34B perform not only the calculation of the current difference but also the judgment of abnormality.
In 4B, only the calculation of the current difference may be performed, and the control circuit 26 may determine an abnormality (that is, compare the current difference with the allowable current difference) based on the calculated current difference.

If the power supply voltage is relatively low and there is no need to worry about arcing at the time of chattering and it is sufficient to consider only a continuous short circuit between the electric wire and the ground, a single current sensor may be connected to the power supply circuit. It is good also as a structure only interposed inside. Also in this case, by incorporating the current sensor in the voltage converter in advance, the wiring structure can be simplified and the wiring operation can be facilitated.

In the present invention, the protection control means may be provided outside the voltage converter. For example, it is possible to forcibly turn off the switch element in the voltage converter by stopping the power supply to the entire voltage converter in an emergency. Also, the specific location of the current detecting means is not particularly limited. For example, the power supply side current sensor may be incorporated in an electric connection box in the engine room, or the load side current sensor may be integrated with the load. You may make it.

However, as shown in the above embodiment, D
If the control circuit for drive control of the switch element built in the voltage converter such as a C-DC converter is provided with an emergency cutoff function and is also used as protection control means, the voltage converter itself can have a circuit protection function. By simply incorporating this voltage converter into a circuit, a control system can be constructed, and wiring work and the like become very simple. Further, by incorporating at least a part of the current detecting means in the voltage converter as shown in FIGS. 2 and 5, the operation of arranging the sensor is also simplified. In particular, in the case of FIG. 5, the DC-DC converter 20, which is a voltage converter, has a configuration in which the control system required for emergency cutoff control is entirely incorporated in the voltage converter. The emergency cutoff device according to the present invention can be simply constructed by the work of merely interposing in the circuit in the same manner as described above.

[0068]

As described above, according to the present invention, power is supplied from the DC power supply to the load by forcibly turning off the inverter switch element of the voltage converter interposed between the on-board DC power supply and the load. Since the emergency cutoff is performed, there is an effect that the vehicle power supply circuit can be properly protected with a simple and inexpensive configuration without providing a switch means dedicated to circuit protection.

[Brief description of the drawings]

FIG. 1 is a diagram showing a vehicle power supply circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a DC-DC converter provided in the circuit shown in FIG.

FIG. 3 is a diagram showing a vehicle power supply circuit according to a second embodiment of the present invention.

FIGS. 4A and 4B are cross-sectional views showing examples of the structure of a cable in the circuit of FIG.

FIG. 5 is a circuit configuration diagram of a DC-DC converter provided in the circuit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 On-board power supply 12 Load 14A, 14B Cable 18A, 18B Current sensor (current detection means) 20 DC-DC converter (voltage converter) 21 High frequency transformer (transformation part) 22 Power switch element 24 Drive circuit 26 Control circuit (Protection control means) 32A, 32B Current detection circuit (current detection unit) 34A, 34B Filter / comparison circuit (judgment unit) 41A, 41B, 42A, 42B Current sensor (current detection unit)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Chen No. 1-7-10 Kikuzumi, Minami-ku, Nagoya-shi, Aichi F-term in Harness Research Institute, Inc. (reference) 5G004 AA04 AB02 BA01 BA03 BA04 BA05 DA02 DB03 EA01 5H007 AA17 CA02 CB07 DB03 DC02 FA03 GA08 5H730 AA20 BB23 DD04 FD31 FD41 FG01 XX04 XX15 XX22 XX23 XX35 XX43

Claims (9)

[Claims] A vehicle power supply circuit for supplying power from a vehicle-mounted DC power supply to a load, wherein a switch element that turns on and off an output voltage of the DC power supply and generates an AC voltage is provided between the DC power supply and the load. A power supply circuit for a vehicle, wherein a power supply circuit for a vehicle is stopped by forcibly turning off a switch element of the voltage converter in an emergency to stop power supply to a load. 2. The method according to claim 1, wherein the switch element of the voltage converter is forcibly turned off upon detection of a short circuit or disconnection of the power supply wire. Emergency shutoff method for vehicle power supply circuit. 3. A vehicle power supply circuit for supplying power from a vehicle-mounted DC power supply to a load, wherein the switch is interposed between the DC power supply and the load, and turns on and off an output voltage of the DC power supply to generate an AC voltage. And a protection control means for forcibly turning off a switch element of the voltage converter to stop power supply from the DC power supply to a load in an emergency. Emergency cutoff device for circuit. 4. The emergency shut-off device for a vehicle power supply circuit according to claim 3, further comprising an abnormality detecting means for detecting an occurrence of an abnormality in the circuit, wherein the voltage conversion is performed when the occurrence of the abnormality is detected by the abnormality detection means. An emergency cutoff device for a vehicle power supply circuit, wherein the protection control means is configured to forcibly turn off a switch element of a switch. 5. The vehicle power supply circuit according to claim 4, wherein said abnormality detection means is a short-circuit detection means for detecting a short-circuit of an electric wire provided in said power supply circuit. Emergency cutoff device for circuit. 6. The power supply for a vehicle according to claim 4, wherein said abnormality detecting means is a disconnection detecting means for detecting a disconnection of an electric wire provided in said power supply circuit. Emergency cutoff device for circuit. 7. An emergency cutoff device for a power supply circuit for a vehicle according to claim 3, further comprising control means for controlling operation of said switch element during power supply to said voltage converter. An emergency shut-off device for a vehicle power supply circuit, wherein means is also used as the protection control means. 8. A vehicle voltage converter provided between a vehicle-mounted DC power supply and a load, comprising: a switch element for turning on and off an output voltage of the DC power supply to generate an AC voltage; and a switch element generated by the switch element. A transformer for transforming the AC voltage, and controls the operation of the switch element during power supply, and forcibly turns off the switch element of the voltage converter when a circuit abnormality signal is input from the DC power supply. A voltage converter for a vehicle, comprising: protection control means for stopping power supply to a load. 9. The vehicle voltage converter according to claim 8, further comprising: a current detector that detects at least one of a current input to the voltage converter and a current output from the voltage converter.
A voltage converter for a vehicle, comprising: a determination unit configured to determine the presence or absence of a circuit abnormality based on the detected current and to generate a circuit abnormality signal when the abnormality is determined.