JP2012255747A - Disconnection detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disconnection detecting device capable of accurately detecting disconnection, even if the length of a power supply path and a conductor resistance value thereof vary.SOLUTION: A disconnection detecting device 1 includes: a power supply portion 100 for supplying power; a power receiving portion 300 to which power is supplied from the power supply portion 100; a cable 200 connecting the power supply portion 100 and the power receiving portion 300; an A/D converter 302 for detecting the voltage of the power receiving portion 300; a memory which is not shown, and stores the voltage detected by the A/D converter 302 when the power supply portion 100 is powered on; and a CPU 103 comparing the voltage stored in the memory with the voltage detected by the A/D converter 302 to detect an abnormal condition between the power supply portion 100 and the power receiving portion 300.

Description

  The present invention relates to a disconnection detection device that detects disconnection of a cable or the like.

2. Description of the Related Art Conventionally, there is known an abnormality detection device that observes a voltage drop amount in a power supply path and detects a disconnection when the voltage falls outside a preset voltage range (see, for example, Patent Document 1).
In this abnormality detection device, as shown in FIG. 4, the voltage drop ΔV between the power supply paths (Ta−Tb) of the DC motor is A / D converted by the internal circuit of the electronic control unit 501, and is converted into digital data by the CPU 504. Is transmitted. The CPU 504 determines whether the voltage drop amount ΔV is within the specified value range, and detects an abnormality in the power supply path.

JP-A-6-93934

  However, in the abnormality detection device disclosed in the above-mentioned Patent Document 1, it is necessary to set a specified value range of the voltage drop amount in advance, so that the power supply path is manufactured to a path length such as a cable or a conductor resistance value. In the case of using a device with a large variation, or in the case of a general-purpose device having a plurality of types of power supply paths, there is an inconvenience that it is difficult to detect disconnection.

  The present invention has been made in view of the above circumstances, and provides a disconnection detection device capable of detecting disconnection with high accuracy even when the length of the power supply path and the conductor resistance value vary. Objective.

In order to achieve the above object, the present invention employs the following means.
The present invention includes a power supply unit that supplies power, a power reception unit that receives power from the power supply unit, a power supply path that connects the power supply unit and the power reception unit, and the power reception unit A voltage detection unit for detecting the voltage of the power supply unit, a voltage storage unit for storing a voltage detected by the voltage detection unit when the power supply unit is turned on, a voltage stored in the voltage storage unit, and the voltage detection unit A disconnection detection device is provided that includes an abnormality detection unit that detects an abnormality between the power supply unit and the power reception unit by comparing the voltage detected by the power supply unit.

  According to the present invention, power is supplied from the power supply unit to the power receiving unit via the power supply path, and the voltage detected by the voltage detection unit is stored in the voltage storage unit when the power supply unit is turned on. Is done. Then, the abnormality detection unit detects the abnormality between the power supply unit and the power receiving unit by comparing the voltage stored in the voltage storage unit with the voltage detected by the voltage detection unit.

  By doing in this way, it is possible to detect an abnormality (excessive voltage drop or voltage rise) between the power supply unit and the power receiving unit without setting the range of the voltage drop amount in advance. Thereby, even when there is a manufacturing variation in the length of the power supply path and the conductor resistance value, the disconnection can be detected with high accuracy.

  In the above invention, a power supply voltage detection unit for detecting the voltage of the power supply unit is provided, the voltage storage unit stores the voltage detected by the power supply voltage detection unit when the power supply unit is turned on, and The abnormality detection unit may detect the abnormality of the power supply unit by comparing the voltage stored in the voltage storage unit with the voltage detected by the power supply voltage detection unit.

  With such a configuration, the power supply voltage detected by the power supply voltage detection unit is stored in the power supply voltage storage unit when the power supply unit is turned on. Then, the abnormality of the power supply unit is detected by comparing the power supply voltage stored in the power supply voltage storage unit with the power supply voltage detected by the power supply voltage detection unit.

  By doing in this way, when an abnormality (excessive voltage drop or voltage rise) is detected between the power supply unit and the power receiving unit, the cause (disconnection, etc.) occurs in the power supply unit. Or whether it is generated between the power supply path and the power receiving unit.

In the above invention, the abnormality detection unit may detect an abnormality from a difference between the voltage of the power receiving unit and the voltage of the power supply unit stored in the voltage storage unit.
By doing in this way, it is possible to detect an abnormality (an excessive voltage drop or voltage rise) between the power supply unit and the power reception unit with higher accuracy.
In the above invention, the voltage storage unit may be provided inside the abnormality detection unit.
By doing in this way, the whole apparatus can be reduced in size.

  In the above invention, the apparatus includes a history determination unit that determines whether or not the power supply to the power receiving unit is the first time. The voltage stored in the voltage storage unit and the voltage detected by the voltage detection unit may be compared to detect an abnormality between the power supply unit and the power reception unit.

  By doing so, power is supplied from the power supply unit to the power receiving unit even when the power supply channel is disconnected when power is not supplied to the power receiving unit (for example, during storage of the power supply channel). In this case, it is possible to detect a disconnection between the power supply unit and the power reception unit.

  According to the present invention, it is possible to detect disconnection with high accuracy even when the length of the power supply path and the conductor resistance value vary.

It is a schematic block diagram of the cable disconnection detection apparatus which concerns on each embodiment of this invention. It is a flowchart which shows the process performed by the cable disconnection detection apparatus which concerns on 1st Embodiment. It is a flowchart which shows the process performed by the cable disconnection detection apparatus which concerns on 2nd Embodiment. It is a schematic block diagram of the conventional cable disconnection detection apparatus.

[First Embodiment]
Hereinafter, a cable breakage detection apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a cable break detection device 1 according to the present embodiment. In FIG. 1, the power supply unit 100 is connected to a power receiving unit 300 via a cable (power supply path) 200.

The power supply unit 100 includes a power generation unit 101, an A / D converter (indicated as “A / DC” in the figure) 102, and a CPU 103.
The power generation unit 101 generates power and supplies power to the load 301 in the power reception unit 300 via the power supply line 201 in the cable 200.
The A / D converter (power supply voltage detection unit) 102 detects the power supply voltage value V1 generated by the power supply generation unit 101, converts it into a digital signal V1D, and outputs it to the CPU 103.

The CPU (abnormality detection unit) 103 is connected to the power generation unit 101, the A / D converter 102, and the A / D converter 302, and the voltage from the digital signals received from the A / D converter 102 and the A / D converter 302 The amount of drop ΔV is calculated as follows, and the power generated by the power generation unit 101 is controlled.
ΔV = | V1D−V2D |
Further, the CPU 103 has a memory (voltage storage unit) 104 that stores the digital signals V1D and V2D and the voltage drop amount ΔV.

The power receiving unit 300 includes a load 301 and an A / D converter (indicated as “A / DC” in the figure) 302.
The A / D converter (voltage detection unit) 302 detects the voltage value V2 supplied to the load 301 via the power supply line 201, converts it to a digital signal V2D, and outputs it to the CPU 103.

The cable 200 includes a power supply line 201 that transmits power and a communication line 202 that transmits a digital signal.
The power supply line 201 connects the power generation unit 101 and the load 301, and guides the power generated by the power generation unit 101 to the load 301.
A communication line 202 is a communication line that connects the A / D converter 302 and the CPU 103 and guides the digital signal V2D converted by the A / D converter 302 to the CPU 103.

The operation of the cable break detection device 1 having the above configuration will be described below with reference to the flowchart of FIG.
First, in step 400, the power supply unit 100 and the power receiving unit 300 are connected by the cable 200, and the power supply is turned on.

  Next, when a voltage is applied from the power supply generation unit 101 of the power supply unit 100 to the load 301 of the power reception unit 300 in step 401, the A / D converters 102 and 302 have voltage values V1 and V2, respectively. The A / D converter 102 converts the voltage value V1 into the digital signal V1D, and the A / D converter 302 converts the voltage value V2 into the digital signal V2D.

  Next, in step 402, the digital signal V1D converted by the A / D converter 102 is output to the CPU 103 inside the power supply unit 100, and the digital signal V2D converted by the A / D converter 302 is The data is output to the CPU 103 through the communication line 202.

Next, in step 403, the CPU 103 calculates the voltage drop amount ΔV from the above-described calculation formula of ΔV = | V1D−V2D |.
Next, in step 404, for example, values within ΔV ± ΔV × 20% are stored in the memory 104 inside the CPU 103 as the upper limit value VH and the lower limit value VL, respectively, with the voltage drop amount ΔV as a reference.

  Here, while power is supplied to the power receiving unit 300, the CPU 103 detects the voltage drop amount ΔV at a desired time interval T, and when the voltage drop amount ΔV exceeds the upper limit value VH in step 405, the cable 103 200 disconnection is detected (step 406), and power supply is stopped (step 407).

Further, while power is being supplied to the power receiving unit 300, the CPU 103 detects an abnormality of the load 301 when the voltage drop ΔV falls below the lower limit value VL in step 408 (step 409), and supplies power. Stop (step 407).
While the change in the voltage drop amount ΔV is not detected in step 405 and step 408, the CPU 103 continues to supply power (step 410).

In the above configuration, if the cable 200 is disconnected during power supply, the total resistance value R of the power supply path of the cable 200 increases, so that the voltage value V2 of the power receiving unit 300 is determined from Ohm's law (V = I × R). The voltage drop amount ΔV (= | V1D−V2D |) increases. For example, when the power supply line 201 is composed of two lines, if one of the two power supply lines 201 is disconnected, the resistance value of the power supply path is doubled and the voltage drop ΔV is doubled. Since ΔV> VH, the CPU 103 stops power supply.
On the other hand, when the load is abnormal, for example, when the load electric element fails in the open mode, the load current becomes small and ΔV <VL, so the CPU 103 similarly stops the power supply.

  As described above, in the cable breakage detection device 1 according to the present embodiment, the upper limit value VH and the lower limit value VL are set from the voltage drop amount ΔV at the start of power supply. Therefore, the disconnection state can be detected with high accuracy even when there is a large variation in the conductor resistance value of the power supply path between cables of the same product, or when multiple types of cables having different cable lengths are used. In addition, since the voltage value V2 of the power receiving unit 300 is converted into a digital signal V2D and output, the number of cores of the communication line 202 can be reduced, and can be applied to a small apparatus.

[Second Embodiment]
Next, a cable disconnection device according to a second embodiment of the present invention will be described below mainly with reference to FIG. Hereinafter, regarding the cable disconnection device 2 of the present embodiment, the points common to the cable disconnection device 1 of the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

  The configuration of the cable disconnection device 2 of the present embodiment is the same as the configuration of the cable disconnection device 1 described in the first embodiment (see FIG. 1). However, the CPU 103 has a nonvolatile memory 104 inside. The CPU (abnormality detection unit, history determination unit) 103 determines whether or not the power supply to the power receiving unit 300 is the first time.

  If the CPU 103 determines that the power supply to the power receiving unit 300 is not the first time, the CPU 103 previously stores the voltage stored in the memory 104 inside the CPU 103 and the voltage detected by the A / D converters 102 and 302. And an abnormality between the power supply unit 100 and the power receiving unit 300 is detected.

Operation | movement of the cable disconnection apparatus 2 of this embodiment is demonstrated below according to the flowchart shown in FIG.
First, in step 501, the CPU 103 determines from the flag data stored in the nonvolatile memory 104 whether or not the power supply to the power receiving unit 300 is the first time. If the flag is a value indicating the first power supply to the power receiving unit 300, the upper limit value VH and the lower limit value VL are calculated according to the same method as in the first embodiment. The calculated upper limit value VH and lower limit value VL are stored in the nonvolatile memory 104 inside the CPU 103 (steps 401 to 404 ′).

  On the other hand, when the CPU 103 determines from the flag that the power supply to the power receiving unit 300 is not the first time, the CPU 103 reads the upper limit value VH and the lower limit value VL stored in the nonvolatile memory 104 inside the CPU 103, Power supply to the receiving unit 300 is started (steps 502 and 503). Since the subsequent operation is the same as that of the first embodiment, the description thereof is omitted here.

  In the above configuration, the CPU 103 compares the upper limit value VH and lower limit value VL set at the first power supply with the voltage drop amount ΔV during power supply, and detects an abnormality, that is, ΔV> VH or ΔV <VL. In this case, the power supply to the power supply path 200 is stopped.

  As described above, according to the cable disconnection device 2 according to the present embodiment, even when the power is not supplied to the power receiving unit 300 (for example, during storage of the cable), the power supply unit 100 is disconnected. When power is supplied from the power supply unit 300 to the power supply unit 300, a disconnection between the power supply unit 100 and the power reception unit 300 can be detected.

  In the present embodiment, whether or not it is the first activation is determined by storing the upper limit value VH and the lower limit value VL in the nonvolatile memory 104 inside the CPU 103 instead of reading the flag as described above. This may be done by determining whether or not.

As mentioned above, although each embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention. For example, the detection accuracy can be improved by changing the time interval T and threshold values (VL, VH) for detecting the voltage drop amount ΔV depending on the type of cable or connector used.

Further, when a plurality of types of cables are not used, the A / D converter 102 shown in FIG. 1 is omitted by using the variation amount of the absolute voltage value of the power receiving unit 300 as a criterion for cable disconnection. It can be configured only by the D converter 302, and it is also possible to provide a low-cost device with a reduced number of voltage detection units.
Furthermore, it is also possible to prompt the operator to take quick action when an abnormality is detected by installing a separate speaker or display device and issuing a warning to the operator by sound or light.

DESCRIPTION OF SYMBOLS 1, 2 Cable disconnection detection apparatus 100 Electric power supply part 101 Power supply generation part 102 A / D converter (power supply voltage detection part)
103 CPU (abnormality detection unit, history determination unit)
104 Memory (voltage storage unit)
200 cable (power supply path)
201 power supply line 202 communication line 300 power receiving unit 301 load 302 A / D converter (voltage detection unit)

Claims (5)

A power supply unit for supplying power;
A power receiving unit to which power is supplied from the power supply unit;
A power supply path connecting the power supply unit and the power receiving unit;
A voltage detection unit for detecting a voltage of the power receiving unit;
A voltage storage unit for storing a voltage detected by the voltage detection unit when the power supply unit is turned on;
Disconnection detection comprising an abnormality detection unit that compares the voltage stored in the voltage storage unit with the voltage detected by the voltage detection unit and detects an abnormality between the power supply unit and the power reception unit. apparatus. A power supply voltage detection unit for detecting the voltage of the power supply unit;
The voltage storage unit stores the voltage detected by the power supply voltage detection unit when the power supply unit is turned on;
The disconnection detection device according to claim 1, wherein the abnormality detection unit detects an abnormality of the power supply unit by comparing a voltage stored in the voltage storage unit with a voltage detected by the power supply voltage detection unit. .   The disconnection detection device according to claim 2, wherein the abnormality detection unit detects an abnormality from a difference between a voltage of the power receiving unit and a voltage of the power supply unit stored in the voltage storage unit.   The disconnection detection device according to claim 1, wherein the voltage storage unit is provided inside the abnormality detection unit. A history determination unit for determining whether power supply to the power receiving unit is the first time,
When the history determination unit determines that it is not the first time, the abnormality detection unit compares the voltage stored in advance in the voltage storage unit with the voltage detected by the voltage detection unit, and The disconnection detection apparatus according to any one of claims 1 to 4, wherein an abnormality is detected between a power supply unit and the power reception unit.

Images