JP6978272B2 - Anomaly detection device for large current circuit and large current circuit device - Google Patents

Description

The present invention relates to an abnormality detection device for a large current circuit and a large current circuit device.

There are various devices (loads) that operate by AC power, such as electric heaters for industrial heating furnaces (see, for example, Patent Documents 1 and 2). The heaters described in Patent Documents 1 and 2 are electric heaters, respectively, and electric power is supplied from a power source via a power supply circuit. This power supply circuit is provided with a disconnection detection circuit for detecting the disconnection of the heater.

In the configuration described in Patent Document 1, when the predetermined effective current value is smaller than the reference current effective value, it is determined that the heater disconnection has occurred. Further, in the configuration described in Patent Document 2, the presence or absence of a heater disconnection is determined based on the detection result of the current after being transformed by the transformer.

Japanese Unexamined Patent Publication No. 2009-70682 ([0044]) Japanese Unexamined Patent Publication No. 5-121147

As an electric heater for an industrial heating furnace, there is a heater that operates with a large current exceeding 1000 A. In such a large current heater, a configuration for detecting whether or not an abnormality such as disconnection has occurred is desired. However, it cannot be said that Patent Document 1 specifically mentions a load that operates at a large current. Here, for example, as described in Patent Document 2, it is conceivable to provide a disconnection detection circuit for the heater in the current path through which the current flows after being transformed by the transformer. However, in this case, it is necessary to provide a disconnection detection circuit in the current path through which a large current flows after being transformed by the transformer. For this reason, the disconnection detection circuit becomes a large circuit that can handle a large current, and the manufacturing cost is high. Furthermore, it is necessary to provide a large safety cover for accommodating the disconnection detection circuit, which leads to an increase in the size of the device and a higher manufacturing cost.

Similar problems exist not only in electric heaters but also in other loads.

In view of the above circumstances, it is an object of the present invention to provide a large current circuit abnormality detection device capable of detecting an abnormality of a load through which a large current flows with a smaller configuration and at low cost, and a large current circuit device. And.

As a result of diligent research, the inventor of the present application has focused on the fact that in a configuration in which an electric heater is heated using a current amplified by a transformer, a regular fluctuation occurs in the current on the primary side of the transformer when the heater is disconnected. did. Then, as a result of further diligent research, the present invention was conceived.

(1) An abnormality detection device for a large current circuit according to a certain aspect of the present invention for solving the above problems is a switching unit that controls on / off of power supply from an AC power supply, and an electric power from this switching unit. Current that detects the current value in the current path between the switching unit and the primary side of the transformer in a large current circuit that is a transformer that steps down the current and has a transformer that supplies the power of the secondary side of the transformer to the load. The AC power supply is a three-phase AC power supply, comprising a detection unit and an abnormality determination unit that determines the presence or absence of an abnormality on the secondary side of the large current circuit using the current detection value of the current detection unit. The switching unit includes three sets of switching elements corresponding to each phase from the three-phase AC power supply, and the current detection unit is provided corresponding to each of the three sets of the switching elements and the corresponding set of the switching. The abnormality determination unit includes three current detection elements for detecting the current flowing through the element, the abnormality determination unit determines the presence or absence of the abnormality using the current detection values of each of the three current detection elements, and the abnormality determination unit determines the presence or absence of the abnormality. , Including the disconnection determination unit, the disconnection determination unit uses the ratio of the maximum value and the minimum value of the three current detection values detected by the three current detection elements to determine whether the load is disconnected. you determine whether or not.

According to this configuration, the current detection unit detects the current value in the current path on the primary side before the voltage is stepped down by the transformer, that is, the current value in the current path on the primary side before the current is amplified by the transformer. As a result, the current detection value detected by the current detection unit is smaller than the current value on the secondary side, which is the current value of the power consumed by the load. Therefore, the current detection unit may be configured as long as it can detect a relatively small current, and can be compact and inexpensive. As a result, it is possible to realize an abnormality detection device for a large current circuit that can detect an abnormality of a load through which a large current flows at a lower cost with a smaller configuration. Further, a current detection element is provided corresponding to each of the three sets of switching elements. This makes it possible to detect an abnormality on the secondary side of the transformer with higher accuracy. Further, since all of the three current detection elements need only be able to detect a relatively small current, the configuration can be inexpensive. As a result, even when a plurality (three) current detection elements are used, the cost of the abnormality detection device can be further reduced. Moreover, the disconnection determination unit can determine the presence or absence of disconnection of the load by a simple calculation by using the ratio of the maximum value and the minimum value of the three current detection values.

(2) When the ratio is less than a predetermined threshold value, the disconnection determination unit may determine that the load is disconnected. According to this configuration, when no current is flowing through the load, the ratio of the maximum value to the minimum value of the three current detection values is less than a predetermined threshold value. Therefore, based on such a decrease in the ratio, the disconnection determination unit can determine that the load is disconnected.
( 3 ) The abnormality determination unit may determine the presence or absence of the abnormality based on the deviation between the current value and the current detection value when no abnormality has occurred in the large current circuit.

According to this configuration, the occurrence of an abnormality on the secondary side of the transformer can be detected through the change in the current detection value on the primary side of the transformer.

( 4 ) The abnormality determination unit includes a deterioration determination unit, and the deterioration determination unit includes a degree of decrease in the three current detection values detected by the three current detection elements from the time when no abnormality is detected. It may be determined whether or not the load has deteriorated based on the above.

According to this configuration, when the load (current path to the load) is deteriorated, the degree of decrease in the current detection value from the time when no abnormality is detected exceeds a predetermined amount. Therefore, based on such a decrease in the current detection value, the deterioration determination unit can determine that the load has deteriorated.

( 5 ) The transformer includes a Scott transformer, and the load is connected to a first load connected to the first system on the secondary side of the Scott transformer and a second system on the secondary side of the Scott transformer. The abnormality determination unit may determine the presence or absence of an abnormality in each of the first load and the second load, including the second load.

According to this configuration, the abnormality determination unit can individually determine the abnormality for each of the two loads provided on the secondary side of the Scott transformer.

( 6 ) In order to solve the above-mentioned problems, the large current circuit device according to a certain aspect of the present invention has a switching unit that controls on / off of power supply from an AC power supply, and a step down of power from this switching unit. It includes a large current circuit including a transformer, a load to which power is applied to the secondary side of the transformer, and an abnormality detection device of the large current circuit .

According to this configuration, the current detection unit detects the current value in the current path on the primary side before the voltage is stepped down by the transformer, that is, the current value in the current path on the primary side before the current is amplified by the transformer. As a result, the current detection value detected by the current detection unit is smaller than the current value on the secondary side, which is the current value of the power consumed by the load. Therefore, the current detection unit may be configured as long as it can detect a relatively small current, and can be compact and inexpensive. As a result, abnormalities in the load through which a large current flows can be detected at low cost with a smaller configuration.

According to the present invention, it is possible to detect an abnormality of a load through which a large current flows with a smaller configuration and at a lower cost.

It is a schematic diagram of the heat treatment apparatus which concerns on one Embodiment of this invention. (A) to (D) are schematic graphs for explaining the current values detected by the three current detection elements, respectively. It is a flowchart for demonstrating an example of the flow of the disconnection determination in the disconnection determination part of an abnormality determination unit. It is a flowchart for demonstrating an example of the flow of deterioration determination in the deterioration determination part of an abnormality determination part. It is a flowchart for demonstrating the modification of the flow of the disconnection determination in the disconnection determination part of an abnormality determination unit.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of a heat treatment apparatus 1 according to an embodiment of the present invention. With reference to FIG. 1, the heat treatment apparatus 1 is arranged in the heat treatment chamber 2 by heating the inside of the heat treatment chamber 2 in a state where the object 100 is arranged in the heat treatment chamber 2 of the heat treatment apparatus 1. The processed object 100 is configured to be heat-treated. The heat treatment apparatus 1 is an example of the "large current circuit apparatus" of the present invention.

As the object to be processed 100, a metal, a substrate, or the like can be exemplified. Examples of the heat treatment when the object to be treated 100 is a metal include carburizing treatment, nitriding treatment, quenching treatment, tempering treatment, and annealing treatment. As the heat treatment when the object 100 to be processed is a substrate, CVD (Chemical Vapor Deposition) treatment, diffusion treatment, annealing treatment, solar cell manufacturing treatment, and semiconductor device manufacturing treatment can be exemplified. The heat treatment apparatus 1 of the present embodiment is a high-temperature heat treatment apparatus capable of heating the atmosphere in the heat treatment chamber 2 to 900 ° C. or higher.

The heat treatment device 1 has a heat treatment chamber 2, a heating device 3 for heating the inside of the heat treatment chamber 2, and an abnormality detection device 4 for detecting an abnormality in the heating device 3.

The heat treatment chamber 2 is provided as a storage chamber for accommodating the object to be treated 100. The heat treatment chamber 2 is formed in a hollow shape, and is configured so that the object to be processed 100 can be taken in and out through a door (not shown).

The heating device 3 uses a three-phase AC power source 5 such as a commercial power source supplied from an electric power company as a power source, and generates heat in a heater unit 7 described later.

The heating device 3 includes a large current circuit 6, a heater unit 7 operated by electric power from the large current circuit 6, and a heating control unit 8 for controlling the operation of the large current circuit 6 (heater unit 7). There is.

The large current circuit 6 steps down the power from the AC power source 5, amplifies the current, and outputs this power to the heater unit 7. In the present embodiment, the large current circuit 6 converts the power of about 200 V in three phases and about 450 A into the large current power of about 20 V in two phases and about 4000 A by the transformer 11 described later.

The large current circuit 6 includes a switching unit 9 that controls on / off of power supply from AC power, a primary side current path 10, a transformer 11 such as a Scott transformer, and a secondary side current path 12.

The switching unit 9 is configured to turn on / off the currents from each of the R phase, the T phase, and the S phase of the AC power supply 5. The switching unit 9 is arranged between the AC power supply 5 and the transformer 11. In the present embodiment, the switching unit 9 is formed by using a thyristor as a switching element. The switching unit 9 may not be formed of a thyristor, but may be formed of a transistor, an FET such as a MOSFET, a relay, or the like.

The switching unit 9 includes a set of switching elements 13R for R phase as three sets of switching elements, a set of switching elements 13T for T phase, and a set of switching elements 13S for S phase. is doing. In the following, a set of switching elements is also simply referred to as a "switching element".

Each set of switching elements 13R, 13T, 13S has a configuration in which a set of thyristors are connected in parallel. That is, the switching unit 9 has three sets of switching elements 13R, 13T, 13S corresponding to each phase from the AC power supply 5. In the present embodiment, in each set of switching elements 13R, 13T, 13S, the thyristors forming the set are arranged so that the orientation of the anode and the orientation of the cathode are opposite to each other.

One end of each set of switching elements 13R, 13T, 13S is connected to the corresponding R-phase, T-phase, and S-phase of the AC power supply 5. That is, one end of a set of switching elements 13R is connected to the R phase of the AC power supply 5, and one end of the set of switching elements 13T is connected to the T phase of the AC power supply 5. One end of the element 13S is connected to the S phase of the AC power supply 5. The switching unit 9 constitutes a part of the primary side current path 10.

The primary side current path 10 is provided to supply the power from the AC power source 5 to the secondary side of the transformer 11. In the present embodiment, the "primary side" indicates a place where the current of the electric power before being stepped down by the transformer 11 flows, and the "secondary side" is the current of the electric power after being stepped down by the transformer 11. Indicates where the current flows.

The primary side current path 10 includes a switching unit 9, an R phase line 14R, a T phase line 14T, an S phase line 14S, and primary side coils 15M and 15T of the transformer 11.

One end of the R phase wire 14R is connected to the other end of the set of switching elements 13R. The other end of the R-phase wire 14R is connected to the U-phase terminal 16U of the primary coil 15M of the transformer 11. One end of the T-phase wire 14T is connected to the other end of a set of switching elements 13T. The other end of the T-phase wire 14T is connected to the W-phase terminal 16W of the primary coil 15M of the transformer 11. One end of the S-phase wire 14S is connected to the other end of the set of switching elements 13S. The other end of the S-phase wire 14S is connected to the V-phase terminal 16V of the primary coil 15T of the transformer 11.

The transformer 11 steps down the power from the switching unit 9, and supplies the stepped-down secondary side large current power to the heater unit 7. That is, the transformer 11 is a power conversion element that converts high-voltage / low-current power on the primary side into low-voltage / high-current power as power on the secondary side. The transformer 11 is a Scott transformer in the present embodiment, and converts a three-phase alternating current into a two-phase alternating current. In the present embodiment, the transformer 11 is provided with three U-phase, W-phase, and V-phase terminals and two coils on the primary side, and on the secondary side, M-seats and T-seats that are separate from each other. It has a configuration in which two coils are provided. The transformer 11 is arranged between the switching unit 9 and the heater unit 7.

The transformer 11 has primary coil 15M and 15T and secondary coil 17M and 17T.

The number of turns of the primary coil 15M and 15T and the number of turns of the secondary coils 17M and 17T are appropriately set according to the desired step-down characteristics. Both ends of one of the primary coil 15M include a U-phase terminal 16U and a W-phase terminal 16W. Further, one end of the other primary coil 15T includes a V-phase terminal 16V. The other end of the other primary coil 15T is a center tap connected to the intermediate portion of one primary coil 15M.

On the other hand, the secondary coil 17M is an example of the "first system on the secondary side of the Scott transformer" of the present invention. One secondary side coil 17M is an M seat coil, and is arranged so as to face the other primary side coil 15M. One end and the other end of the secondary coil 17M are electrically connected to a pair of terminals of the M seat heater 18M of the heater unit 7, and a current from the secondary coil 17M flows through the M seat heater 18M.

Similarly, the other secondary coil 17T is an example of the "second system of the secondary side of the Scott transformer" of the present invention. The other secondary coil 17T is a T-seat coil and is arranged so as to face the other primary coil 15T. One end and the other end of the secondary coil 17T are electrically connected to a pair of terminals of the T-seat heater 18T of the heater unit 7, and a current from the secondary coil 17T flows through the T-seat heater 18T. The transformer 11 having the above configuration constitutes a part of the secondary current path 12.

The secondary side current path 12 includes the secondary side coils 17M and 17T of the transformer 11 and the heater unit 7.

The heater unit 7 has an M-seat heater 18M and a T-seat heater 18T. The M-seat heater 18M and the T-seat heater 18T are examples of the "load, first load" and "load, second load" of the present invention, respectively. The M-seat heater 18M and the T-seat heater 18T are electric heaters, respectively, and generate heat by being supplied with electric power from the corresponding secondary coil 17M and 17T.

In the present embodiment, the heaters 18M and 18T are electric heating (resistance heating) heaters including a bus bar which is a heating wire having a rectangular cross section. In the present embodiment, since each of the heaters 18M and 18T is passed a large current, the dimension of the bus bar in the axial cross section is an extremely large value of, for example, 200 mm × 12 mm. In the present embodiment, the pair of terminals of the heating wire of the M seat heater 18M are connected to the pair of terminals of the secondary coil 17M. Similarly, a pair of terminals of the heating wire of the T-seat heater 18T are connected to a pair of terminals of the secondary coil 17T.

With the above configuration, the secondary side coil 17M and the heater 18M form an M seat side current path 19M. Further, the secondary side coil 17T and the heater 18T form a T-seat side current path 19T. The heating control unit 8 controls the energization of these heaters 18M and 18T.

The heating control unit 8 has a configuration for outputting a predetermined output signal based on a predetermined input signal, and can be formed by using, for example, a safety programmable controller or the like. The safety programmable controller means a publicly certified programmable controller having the safety function of SIL2 or SIL3 of JIS (Japanese Industrial Standards) C0508-1. The heating control unit 8 may be formed by using a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory).

The heating control unit 8 is connected to the switching unit 9. In the present embodiment, the heating control unit 8 controls the current path in the primary side current path 10 by controlling the current supply to the gate electrode in each of the set of switching elements 13R, 13T, 13S, thereby controlling the current path. , The heating amount of each heater 18M, 18T is controlled.

Next, the configuration of the abnormality detection device 4 will be described.

The abnormality detection device 4 is provided to monitor the presence or absence of an abnormality in the heating device 3. In the present embodiment, the abnormality detection device 4 determines whether or not there is deterioration and whether or not there is a disconnection in each of the heaters 18M and 18T (secondary current path 12). In this case, "deterioration" means that the electric resistance is increased by a predetermined value or more as compared with the normal state due to deterioration of the heating wire or the like. Further, the "disconnection" in this case means that the current does not flow due to the burning of the heating wire or the like.

In the present embodiment, the current flowing through the heaters 18M and 18T is as large as about 4000A, and the bus bar of the heaters 18M and 18T is thick. Therefore, a large-scale sensor is required to detect the current of the bus bars of the heaters 18M and 18T. On the other hand, in the present embodiment, the abnormality detecting device 4 is configured to detect the current in the primary side current path 10 having a relatively small current value. That is, it is not necessary to provide a current sensor and a safety cover for the current sensor on the large bus bars of the heaters 18M and 18T.

The abnormality detection device 4 includes a current detection unit 21, an abnormality determination unit 22, and a display unit 23.

In the present embodiment, the abnormality detection device 4 is configured to be detachable from the large current circuit 6. Specifically, the abnormality detection device 4 is arranged in a control panel (not shown) in which the switching unit 9 is housed. The current detection unit 21 is detachably installed in the primary side current path 10. With such a configuration, the abnormality detection device 4 can be easily installed in the large current circuit 6 with a small number of man-hours by retrofitting.

The current detection unit 21 is provided to detect the current value in the current path (primary side current path 10) between the switching unit 9 in the large current circuit 6 and the primary coil 15M, 15T of the transformer 11. .. The current detection unit 21 includes three current detection elements 25R, 25T, and 25S.

The current detection elements 25R, 25T, 25S are provided corresponding to each of the three sets of switching elements 13R, 13T, 13S, and detect the current flowing through the corresponding set of switching elements 13R, 13T, 13S. Each current detecting element 25R, 25T, 25S is an alternating current sensor for detecting an alternating current. As such a sensor, various known sensors can be used. In the present embodiment, each current detection element 25R, 25T, 25S is formed by a sensor using a current transformer method, and has a CT (Current Transformer) in which a toroidal winding is applied to a cylindrical ring core. There is. Therefore, in FIG. 1, each current detection element 25R, 25T, 25S is schematically shown in a cylindrical shape.

Each current detection element 25R, 25T, 25S is arranged so as to surround the corresponding R-phase wire 14R, T-phase wire 14T, and S-phase wire 14S, and the corresponding R-phase wire 14R, T-phase wire 14T, And, the current value of the S phase line 14S is detected. That is, the current detecting element 25R detects the current of the R phase wire 14R, the current detecting element 25W detects the current of the T phase wire 14T, and the current detecting element 25S detects the current of the S phase wire 14S.

In the present embodiment, each current detection element 25R, 25T, 25S is a voltage signal corresponding to the strength of the current when a current flows through the corresponding R-phase wire 14R, T-phase wire 14T, and S-phase wire 14S. Occurs. Then, this voltage signal is given to the abnormality determination unit 22 as a current detection result.

The abnormality determination unit 22 uses the current detection values cR, cT, cS (effective value) of each current detection element 25R, 25T, 25S to make an abnormality in the secondary side current path 12 (heater 18M, 18T) of the large current circuit 6. Judge the presence or absence of. In the present embodiment, the abnormality determination unit 22 has the current values of the switching elements 13R, 13T, 13S when no abnormality has occurred in the large current circuit 6, and the actually detected current detection values cR, cT, cS. The presence or absence of an abnormality is determined based on the deviation (change in balance between current detection values cR, cT, and cS). The abnormality determination unit 22 has a configuration for outputting a predetermined output signal based on a predetermined input signal, and can be formed by using, for example, the above-mentioned safety programmable controller or the like. The abnormality determination unit 22 may be formed by using a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory).

The abnormality determination unit 22 may be configured by software by the above-mentioned safety programmable controller or computer, or may be configured by hardware using an electric circuit.

In the present embodiment, the abnormality determination unit 22 will be described as being provided independently of the heating control unit 8 and arranged in the above-mentioned control panel, but it may not be the same. For example, the abnormality determination unit 22 may be formed by using the same safety programmable controller or computer as the heating control unit 8.

The abnormality determination unit 22 includes an A / D conversion unit 26, a disconnection determination unit 27, and a deterioration determination unit 28.

The A / D conversion unit 26 converts the current detection signal, which is an analog signal output from each current detection element 25R, 25T, 25S, into a digital signal and outputs the current detection signal to the disconnection determination unit 27 and the deterioration determination unit 28.

The disconnection determining unit 27 is provided to determine whether or not there is a disconnection in the secondary side current path 12, in particular, whether or not there is a disconnection in the M-seat heater 18M and whether or not there is a disconnection in the T-seat heater 18T. Further, the deterioration determination unit 28 determines whether or not the wiring in the secondary side current path 12 is deteriorated, particularly whether or not the wiring is deteriorated in the M-seat heater 18M and whether or not the wiring is deteriorated in the T-seat heater 18T. It is provided for the purpose.

The disconnection determination unit 27 includes the current values of the switching elements 13R, 13T, 13S of the primary side current path 10 when no abnormality has occurred in the large current circuit 6, and the currents detected by the respective current detection elements 25R, 25T, 25S. The presence or absence of disconnection is determined based on the deviation from the detected values cR, cT, and cS. Similarly, the deterioration determination unit 28 detects the current values of the switching elements 13R, 13T, 13S of the primary side current path 10 and the current detection elements 25R, 25T, 25S when no abnormality has occurred in the large current circuit 6. The presence or absence of deterioration is determined based on the deviation from the detected current detection values cR, cT, and cS.

The above-mentioned "when no abnormality has occurred" means, for example, a case where the heat treatment apparatus 1 operates according to the design specifications. Further, the disconnection determination unit 27 and the deterioration determination unit 28 are configured to individually recognize the current detection values cR, cT, and cS. That is, the disconnection determination unit 27 and the deterioration determination unit 28 do not recognize the current detection values cR, cT, and cS as mere three numerical values, but recognize them as numerical values associated with the phase lines 14R, 14T, and 14S. ..

In the present embodiment, the disconnection determination unit 27 uses the ratio of the maximum value to the minimum value of the three current detection values cR, cT, cS detected by the three current detection elements 25R, 25T, 25S. For each of the heaters 18M and 18T, it is determined whether or not a disconnection has occurred. Here, a method for determining disconnection by the disconnection determining unit 27 will be described.

2A to 2D are schematic graphs for explaining the current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S, respectively. More specifically, FIG. 2A shows the current detection values cR, cT, and cS when the large current circuit 6 is driven in the normal state where no abnormality has occurred. FIG. 2B shows the current detection values cR, cT, and cS when the large current circuit 6 is driven when the M seat heater 18M is disconnected. FIG. 2C shows the current detection values cR, cT, and cS when the large current circuit 6 is driven when the T-seat heater 18T is disconnected. FIG. 2D shows the current detection values cR, cT, and cS in the normal state (when no abnormality has occurred), when the M-seat heater 18M is disconnected, and when the T-seat heater 18T is disconnected. The ratio between the maximum value and the minimum value of is shown.

In each of FIGS. 2A to 2D, the horizontal axis shows the output ratio of the large current circuit 6 when the rated output of the large current circuit 6 (heater unit 7) is 100%. .. Further, the vertical axis shows each current detection value cR, cT, cS. The coefficient α on the vertical axis is a constant and is a value corresponding to the current value in the primary side current path 10 of the large current circuit 6.

With reference to FIGS. 1 and 2A, during normal operation of the heat treatment apparatus 1, the current detection values cR, cT, and cS of the large current circuit 6 show substantially the same values at any output.

Next, the time when the M seat heater 18M is disconnected will be described.

When the M-seat heater 18M is disconnected, as shown in FIGS. 1 and 2B, the current detection value cS at the S-phase line 14S (V-phase terminal 16V) is the highest among the current detection values cR, cT, and cS. , The current detection value cT lower than the current detection value cS is detected, and further, the current detection value cR lower than the current detection value cT is detected. This is because the primary coil 15M for supplying power to the disconnected M seat heater 18M among the primary coils 15M and 15T has R phase wires 14R and T phase wires at the terminals 16U and 16W at both ends of the primary coil 15M. This is because it is connected to 14T. A relatively low current flows through these R-phase wires 14R and T-phase wires 14T because power is not consumed by the M-seat heater 18M. On the other hand, among the primary coil 15M and 15T, the S-phase wire 14S connected to the V-phase terminal 16V of the primary coil 15T for supplying power to the unbroken T-seat heater 18T is powered by the T-seat heater 18T. Is consumed, so that a relatively high current flows. That is, the current detection value cS in the switching element 13S connected to the primary side coil 15T for the unbroken heater 18T is relatively high, and the switching element 13R connected to the primary side coil 15M for the disconnected heater 18M, The current detection values cR and cT at 13T are relatively low. At this time, the ratio cR / cS of the maximum value cS and the minimum value cR of the three current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S is calculated by the disconnection determination unit 27. Will be done. Then, the disconnection determination unit 27 determines whether or not the heater 18M has a disconnection by using this ratio cR / cS. Specifically, with reference to FIGS. 1, 2 (B) and 2 (D), the ratio cR / cS is less than the predetermined threshold value ThM1, and the current detection values cR, cT, cS. When the current detection value cS is the maximum among them, the disconnection determination unit 27 determines that the heater 18M is disconnected. On the other hand, when the ratio cR / cS is less than the predetermined threshold value ThM1, but the current detection value cS is not the maximum among the current detection values cR, cT, cS, or the ratio cR / cS is the predetermined threshold. When the value is ThM1 or more, the disconnection determination unit 27 determines that the heater 18M is not disconnected.

Next, the time when the T-seat heater 18T is disconnected will be described.

When the T-seat heater 18T is disconnected, as shown in FIGS. 1 and 2C, the current detection value cR at the R phase line 14R (U-phase terminal 16U) is the highest among the current detection values cR, cT, and cS. , A current detection value cT which is substantially the same as the current detection value cR but is lower than the current detection value cR is detected, and further, a current detection value cS significantly lower than the current detection value cT is detected. This is because the primary side coil 15T for supplying power to the disconnected T seat heater 18T among the primary side coils 15M and 15T is connected to the S phase wire 14S at the V phase terminal 16V of the primary side coil 15T. Is. A relatively low current flows through the S-phase wire 14S because the T-seat heater 18T does not consume electric power. On the other hand, among the primary coil 15M and 15T, the R and T phase wires 14R and 14T connected to the U and W phase terminals 16U and 16W of the primary coil 15M for supplying power to the M seat heater 18M which is not broken. In, a relatively high current flows due to the consumption of electric power by the M seat heater 18M. That is, the current detection value cR in the switching element 13R connected to the primary side coil 15M for the unbroken heater 18M is relatively high, and the switching element 13S connected to the primary side coil 15T for the disconnected heater 18T has a relatively high current detection value cR. The current detection value cS becomes relatively low. At this time, the heater 18M is disconnected by using the ratio cS / cR of the maximum value cR and the minimum value cS of the three current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S. Is determined. Specifically, with reference to FIGS. 1, 2 (C) and 2 (D), the ratio cS / cR is less than the predetermined threshold value ThT1 and the current detection values cR, cT, cS. When the current detection value cS is the smallest, the disconnection determination unit 27 determines that the heater 18T is disconnected. On the other hand, when the ratio cR / cS is less than the predetermined threshold value ThT1, but the current detection value cS is not the minimum among the current detection values cR, cT, cS, or the ratio cR / cS is the predetermined threshold. When the value is ThT1 or more, the disconnection determination unit 27 determines that the heater 18T is not disconnected.

The above is the configuration of the disconnection determination unit 27. Next, the configuration of the deterioration determination unit 28 will be described.

The deterioration determination unit 28 is a heater based on the degree of decrease of each of the three current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S from the time when no abnormality is detected. It is determined whether or not the 18M and 18T (M seat side current path 19M and T seat side current path 19T) are deteriorated.

Next, the time when the M seat heater 18M is deteriorated will be described.

With reference to FIGS. 1 and 2B, when the M-seat heater 18M is deteriorated, the S-phase wire 14S (V-phase terminal) of the current detection values cR, cT, and cS is the same as when the M-seat heater 18M is disconnected. The current detection value cS at 16V) is the highest, the current detection value cT lower than the current detection value cS is detected, and the current detection value cR lower than the current detection value cT is detected. Although FIG. 2B shows the disconnection of the M-seat heater 18M, the current detection values cR, cT, and cS are the disconnection of the M-seat heater 18M even when the M-seat heater 18M is deteriorated. The same tendency (magnitude relationship of each current detection value cR, cT, cS) is established. That is, the current detection value cS in the switching element 13S connected to the primary side coil 15T for the non-deteriorated heater 18T is relatively high, and the switching element 13R connected to the primary side coil 15M for the deteriorated heater 18M, The current detection values cR and cT at 13T are relatively low. Here, among the three current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S, the V-phase terminal of the primary coil 15T for supplying power to the heater 18T that has not deteriorated. The current detection value cS of the S phase wire 14S connected to 16V is a relatively large current value. Further, the average values of the current detection values cR and cT of the R-phase wire 14R and the T-phase wire 14T connected to the U-phase terminal 16U and the W-phase terminal 16W of the primary coil 15M for supplying power to the deteriorated heater 18M ( cR + cT) / 2 is a relatively small current value. In this case, these ratios {(cR + cT) / 2} / cS are calculated by the deterioration determination unit 28. Then, the deterioration determination unit 28 determines whether or not the heater 18M is deteriorated by using this ratio {(cR + cT) / 2} / cS. Specifically, when the ratio {(cR + cT) / 2} / cS is less than the predetermined threshold value ThM2 and the current detection value cS is the largest among the current detection values cR, cT, cS, the deterioration occurs. The determination unit 28 determines that the heater 18M has deteriorated. On the other hand, when the ratio {(cR + cT) / 2} / cS is less than the predetermined threshold value ThM2, but the current detection value cS is not the minimum among the current detection values cR, cT, cS, or the ratio {( When cR + cT) / 2} / cS is equal to or higher than the predetermined threshold value ThM2, the deterioration determination unit 28 determines that the heater 18M has not deteriorated.

Next, the time when the T-seat heater 18T is deteriorated will be described.

With reference to FIGS. 1 and 2 (C), when the T-seat heater 18T is deteriorated, the R-phase wire 14R (U-phase terminal) of the current detection values cR, cT, and cS is the same as when the T-seat heater 18T is disconnected. The current detection value cR in 16U) is the highest, and a current detection value cT that is substantially the same as the current detection value cR but lower than the current detection value cR is detected, and further, it is significantly higher than the current detection value cT. A low current detection value cS is detected. Although FIG. 2C shows the time when the T-seat heater 18T is disconnected, the current detection values cR, cT, and cS are the time when the T-seat heater 18T is disconnected even when the T-seat heater 18T is deteriorated. The same tendency (magnitude relationship of each current detection value cR, cT, cS) is established. That is, the current detection values cR and cT in the switching elements 13R and 13T connected to the primary side coil 15M for the non-deteriorated heater 18M are relatively high, and they are connected to the primary side coil 15T for the deteriorated heater 18T. The current detection value cS in the switching element 13S becomes relatively low. Here, among the three current detection values cR, cT, and cS detected by the three current detection elements 25R, 25T, and 25S, the U-phase terminal of the primary coil 15M for supplying power to the heater 18M that has not deteriorated. The average value (cR + cT) / 2 of the current detection values cR and cT of the R-phase wire 14R and the T-phase wire 14T connected to the 16U and the W-phase terminal 16W is a relatively large current value. Further, the current detection value cS of the S-phase wire 14S connected to the V-phase terminal 16V of the primary coil 15T for supplying power to the deteriorated heater 18T is a relatively small current value. In this case, these ratios cS / {(cR + cT) / 2} are calculated by the deterioration determination unit 28. Then, the deterioration determination unit 28 determines whether or not the heater 18T is deteriorated by using this ratio cS / {(cR + cT) / 2}. Specifically, when the ratio cS / {(cR + cT) / 2} is less than the predetermined threshold value ThT2 and the current detection value cS is the smallest among the current detection values cR, cT, cS, the deterioration occurs. The determination unit 28 determines that the heater 18T has deteriorated. On the other hand, when the ratio cS / {(cR + cT) / 2} is less than the predetermined threshold value ThT2, but the current detection value cS is not the minimum among the current detection values cR, cT, cS, or the ratio cS / When {(cR + cT) / 2} is equal to or higher than the predetermined threshold value ThT2, the deterioration determination unit 28 determines that the heater 18T has not deteriorated.

The signal indicating the result of the disconnection determination and the deterioration determination by the above configuration is output from the determination units 27 and 28 to the display unit 23. The display unit 23 is, for example, a display device having a liquid crystal display unit, and is configured to show the determination result of the abnormality determination unit 22. When the detection result that the M-seat heater 18M is disconnected is output from the disconnection determination unit 27 to the display unit 23, the display unit 23 displays "The M-seat heater is disconnected." Similarly, when the detection result that the T-seat heater 18T is disconnected is output from the disconnection determination unit 27 to the display unit 23, the display unit 23 displays "The T-seat heater is disconnected." ..

Further, when the detection result that the M-seat heater 18M is deteriorated is output from the deterioration determination unit 28 to the display unit 23, the display unit 23 displays "The M-seat heater is deteriorated." Similarly, when the detection result that the T-seat heater 18T is deteriorated is output from the deterioration determination unit 28 to the display unit 23, the display unit 23 displays "The T-seat heater is deteriorated." ..

In this embodiment, the mode in which the determination result of the abnormality determination unit 22 is output to the display unit 23 is described as an example, but this may not be the case. For example, the determination result of the abnormality determination unit 22 may be output to the heating control unit 8, and the heating control unit 8 may control the large current circuit 6 according to this result. In this case, for example, the heating control unit 8 controls the operation of the switching unit 9 so as to stop the energization of the heaters 18M and 18T for which disconnection or deterioration is detected.

Next, an example of the flow of abnormality determination in the abnormality determination unit 22 described above will be described.

FIG. 3 is a flowchart for explaining an example of the flow of disconnection determination in the disconnection determination unit 27 of the abnormality determination unit 22. In the following, when the description is made with reference to the flowchart, the drawings other than the flowchart will be referred to as appropriate.

With reference to FIG. 3, the disconnection determination unit 27 first reads the current detection values cR, cT, and cS from the current detection elements 25R, 25T, and 25S (step S11).

Next, the disconnection determination unit 27 calculates the ratio cR / cS of the minimum value cR and the maximum value cS when the M seat heater 18M is disconnected among the current detection values cR, cT, and cS (step S12). .. When the ratio cR / cS is less than the threshold value ThM1 (YES in step S12), the disconnection determination unit 27 determines whether or not the current detection value cS is the largest among the current detection values cR, cT, and cS. (Step S13). If YES in step S13, the disconnection determination unit 27 determines that the M seat heater 18M is disconnected (step S14). In this case, the disconnection determination unit 27 subsequently performs disconnection determination (steps S16 to S19) of the heater 18T.

On the other hand, when the ratio cR / cS is less than the predetermined threshold value ThM1 (YES in step S12), but the current detection value cS is not the maximum among the current detection values cR, cT, cS (NO in step S13). Or, when the ratio cR / cS is equal to or higher than the predetermined threshold value ThM1 (NO in step S12), the disconnection determination unit 27 determines that the heater 18M is not disconnected (step S15). In this case, the disconnection determination unit 27 subsequently performs disconnection determination (steps S16 to S19) of the heater 18T.

In step S16, the disconnection determination unit 27 calculates the ratio cS / cR of the minimum value cS and the maximum value R when the T-seat heater 18T is disconnected among the current detection values cR, cT, and cS. When the ratio cS / cR is less than the threshold value ThT1 (YES in step S16), the disconnection determination unit 27 determines whether or not the current detection value cS is the smallest among the current detection values cR, cT, and cS. (Step S17). If YES in step S17, the disconnection determination unit 27 determines that the T-seat heater 18T is disconnected (step S18).

On the other hand, when the ratio cR / cS is less than the predetermined threshold value ThT1 (YES in step S16), but the current detection value cS is not the minimum among the current detection values cR, cT, cS (NO in step S17). Or, when the ratio cR / cS is equal to or higher than the predetermined threshold value ThT1 (NO in step S16), the disconnection determination unit 27 determines that the heater 18T is not disconnected (step S19).

The above is an example of the flow of disconnection determination in the disconnection determination unit 27. Next, an example of the flow of deterioration determination in the deterioration determination unit 28 will be described.

FIG. 4 is a flowchart for explaining an example of the flow of deterioration determination in the deterioration determination unit 28 of the abnormality determination unit 22.

With reference to FIG. 4, the deterioration determination unit 28 first reads the current detection values cR, cT, and cS from the current detection elements 25R, 25T, and 25S (step S21).

Next, the deterioration determination unit 28 sets the average value (cR + cT) / 2 of the current detection values cT, cR, which greatly decreases when the M seat heater 18M is deteriorated among the current detection values cR, cT, cS, and these. The ratio {(cR + cT) / 2} / cS to the current detection value cS larger than each of the current detection values cT and cR is calculated (step S22). When the ratio {(cR + cT) / 2} / cS is less than the threshold value ThM2 (YES in step S22), the deterioration determination unit 28 has the maximum current detection value cS among the current detection values cR, cT, and cS. It is determined whether or not there is (step S23). If YES in step S23, the deterioration determination unit 28 determines that the M seat heater 18M has deteriorated (step S24). In this case, the deterioration determination unit 28 subsequently performs deterioration determination (steps S26 to S29) of the T-seat heater 18T.

On the other hand, when the ratio {(cR + cT) / 2} / cS is less than the predetermined threshold value ThM2 (YES in step S22), but the current detection value cS is not the maximum among the current detection values cR, cT, cS. (NO in step S23) or when the ratio {(cR + cT) / 2} / cS is equal to or higher than the predetermined threshold value ThM2 (NO in step S22), the deterioration determination unit 28 deteriorates the M seat heater 18M. It is determined that it is not (step S25). In this case, the deterioration determination unit 28 subsequently performs deterioration determination (steps S26 to S29) of the heater 18T.

Next, the deterioration determination unit 28 has a cS that greatly decreases when the T-seat heater 18T is deteriorated among the current detection values cR, cT, and cS, and a current detection value cR, cT that is larger than the current detection value cS. The ratio cS / {(cR + cT) / 2} to the average value (cR + cT) / 2 of the above is calculated (step S26). When the ratio cS / {(cR + cT) / 2} is less than the threshold value ThT2 (YES in step S26), the deterioration determination unit 28 has the smallest current detection value cS among the current detection values cR, cT, and cS. It is determined whether or not there is (step S27). If YES in step S27, the deterioration determination unit 28 determines that the T-seat heater 18T has deteriorated (step S28).

On the other hand, when the ratio cS / {(cR + cT) / 2} is less than the predetermined threshold value ThT2 (YES in step S26), but the current detection value cS is not the minimum among the current detection values cR, cT, cS. (NO in step S27) or when the ratio cS / {(cR + cT) / 2} is equal to or higher than the predetermined threshold value ThM2 (NO in step S26), the deterioration determination unit 28 has not deteriorated the heater 18T. (Step S29).

The above is an example of the flow of deterioration determination in the deterioration determination unit 28.

As described above, according to the present embodiment, the current value in the primary side current path 10 before the voltage is stepped down by the transformer 11, that is, the current value in the primary side current path 10 before the current is amplified by the transformer 11. , The current detection unit 21 detects the current detection values cR, cT, and cS. As a result, the current detection values cR, cT, and cS detected by the current detection unit 21 are smaller than the current value of the secondary side current path 12, which is the current value of the power consumed by the heaters 18M and 18T. Therefore, the current detection unit 21 may be configured as long as it can detect a relatively small current, and can be compact and inexpensive. As a result, it is possible to realize an abnormality detecting device 4 capable of detecting an abnormality of the heaters 18M and 18T through which a large current flows at a smaller cost and at a lower cost.

Further, according to the present embodiment, since the abnormality detection device 4 can be housed in the control panel (not shown) together with the switching unit 9, the entire heat treatment device 1 can be made compact.

Further, by installing the current detection unit 21 adjacent to the switching unit 9, the abnormality detection device 4 is retrofitted to the large current circuit 6 (the abnormality detection device 4 is installed after the large current circuit 6 is installed). Can be easily done. Moreover, since the abnormality detection device 4 can be installed in the large current circuit 6 by a simple process of installing the current detection unit 21 adjacent to the switching unit 9, the man-hours required for the installation work of the abnormality detection device 4 can be reduced. .. As a result, the installation cost of the abnormality detection device 4 can be reduced.

Further, by using the abnormality detection device 4, the timing of replacement of the heaters 18M and 18T can be grasped more clearly, so that more stable operation of the heat treatment device 1 can be realized.

Further, according to the present embodiment, the abnormality determination unit 22 is based on the deviation between the current value of the primary side current path 10 and the current detection values cR, cT, and cS when no abnormality has occurred in the large current circuit 6. Determine if there is an abnormality. According to this configuration, the occurrence of an abnormality in the secondary side current path 12 of the transformer 11 can be detected through changes in the current detection values cR, cT, and cS of the primary side current path 10 of the transformer 11.

Further, according to the present embodiment, current detection elements 25R, 25T, 25S are provided corresponding to each of the three sets of switching elements 13R, 13T, 13S. Thereby, the abnormality in the secondary side current path 12 of the transformer 11 can be detected more accurately. Further, since all of the three current detection elements 25R, 25T, and 25S need only be able to detect a relatively small current, the configuration can be inexpensive. Thereby, even when a plurality (three) current detection elements 25R, 25T, 25S are used, the cost of the abnormality detection device 4 can be further reduced.

Further, according to the present embodiment, the disconnection determination unit 27 uses the ratio of the maximum value and the minimum value of the three current detection values cR, cT, and cS to determine whether or not the heaters 18M and 18T are disconnected. judge. According to this configuration, the disconnection determination unit 27 can determine the presence or absence of disconnection of the heaters 18M and 18T by a simple calculation by using the ratio of the maximum value and the minimum value of the three current detection values cR, cT, and cS. ..

Further, according to the present embodiment, when the ratio cR / cS is less than the threshold value ThM1, the disconnection determination unit 27 determines that the heater 18M is disconnected, and the ratio cS / cR is less than the threshold value ThT1. If this is the case, it is determined that the heater 18T has a disconnection. According to this configuration, when no current is flowing through the heaters 18M and 18T, the ratio (cR / cS; cS / cR) between the maximum and minimum values of the three current detection values cR, cT and cS is a predetermined threshold. The values are less than ThM1 and ThT1. Therefore, based on such a decrease in the ratio, the disconnection determination unit 27 can determine that the heaters 18M and 18T have a disconnection.

Further, according to the present embodiment, the deterioration determination unit 28 has deteriorated the heaters 18M and 18T based on the degree of decrease from the time when no abnormality is detected in the three current detection values cR, cT and cS. Judge whether or not. According to this configuration, when the heaters 18M and 18T (current paths 19M and 19T) are deteriorated, the degree of decrease in the corresponding current detection values cR, cT and cS from the time when no abnormality is detected is a predetermined amount. Exceed. Therefore, based on such a decrease in the current detection values cR, cT, and cS, the deterioration determination unit 28 can determine that the heaters 18M and 18T have deteriorated.

Further, according to the present embodiment, the abnormality determination unit 22 determines the presence or absence of an abnormality in each of the heater 18M and the heater 18T. According to this configuration, the abnormality determination unit 22 can individually determine an abnormality for each of the two heaters 18M and 18T provided on the secondary side of the transformer 11.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. The present invention can be modified in various ways as described in the claims.

(1) In the above-described embodiment, the disconnection determination unit 27 determines whether or not the current detection value cS of the S phase among the current detection values cR, cT, and cS is the maximum value in the disconnection determination of the heater 18M (. Along with step S13), a mode of determining whether or not the current detection value cS of the S phase among the current detection values cR, cT, and cS is the minimum value in the disconnection determination of the heater 18T has been described as an example. However, this does not have to be the case. For example, the disconnection determination unit 27 extracts the maximum value cmax and the minimum value cmin from the current detection values cR, cT, and cS, and simply determines the disconnection based on the ratio of these maximum value cmax and the minimum value xmin. You may. An example of such a disconnection determination will be described more specifically.

FIG. 5 is a flowchart for explaining a modified example of the flow of disconnection determination in the disconnection determination unit 27 of the abnormality determination unit 22.

With reference to FIG. 5, the disconnection determination unit 27 first reads the current detection values cR, cT, and cS from the current detection elements 25R, 25T, and 25S (step S31).

Next, the disconnection determination unit 27 extracts the maximum value cmax and the minimum value cmin from the current detection values cR, cT, and cS (step S32).

For example, in the normal state where neither the M-seat heater 18M nor the T-seat heater 18T has an abnormality, the current detection values cR, cT, and cS show substantially the same values as shown in FIG. 2 (A). In this case, the maximum value cmax and the minimum value cmin are extracted from the current detection values cR, cT, and cS according to the situation at that time such as noise mixing.

Further, when the M-seat heater 18M is disconnected, as shown in FIG. 2B, the current detection value cS becomes the maximum value cmax, and the current detection value cR becomes the minimum value cmin. Further, when the T-seat heater 18T is disconnected, as shown in FIG. 2C, the current detection value cR becomes the maximum value cmax, and the current detection value cS becomes the minimum value cmin.

Next, the disconnection determination unit 27 determines the ratio of the maximum value cmax to the minimum value cmin, that is, whether or not cmin / cmax is less than the threshold value ThM1 (step S33). When cmin / cmax ≧ ThM1, that is, when cmin / cmax is in the range of the threshold value ThM1 line or more, as shown in FIG. 2D, the disconnection determination unit 27 disconnects the heaters 18M and 18T. It is determined that it is not (step S34).

On the other hand, when cmin / cmax <ThM1 (YES in step S33), that is, when cmin / cmax is in the range below the threshold value ThM1 line of FIG. Determines whether or not is equal to or greater than the threshold value ThT1 (whether or not cmin / cmax is between the ThM1 line and the ThT1 line of FIG. 2D) (step S35). When cmin / cmax is equal to or higher than the threshold value ThT1 (YES in step S35 when cmin / cmax is between the ThM1 line and the ThT1 line in FIG. 2D), the disconnection determination unit 27 is the M seat heater 18M. Is determined to be broken (step S36).

On the other hand, when cmin / cmax is less than the threshold value ThT1 (NO in step S35 when cmin / cmax is below the ThT1 line in FIG. 2D), the disconnection determination unit 27 is the T-seat heater 18T. Is determined to be broken (step S37).

In the modified example shown in FIG. 5 described above, the disconnection determination unit 27 does not need to individually recognize the current detection values cR, cT, and cS, and is selected from these three current detection values cR, cT, and cS. Two values are extracted as the maximum value cmax and the minimum value cmin. As a result, it is not necessary to provide a step (steps S13, S17 in FIG. 3) for determining whether or not the current detection value cS of the S phase among the current detection values cR, cT, and cS is the maximum value or the minimum value. The disconnection determination unit 27 can determine the disconnection with a simpler calculation.

(2) Further, in the above-described embodiment, a mode in which a three-phase AC power supply is used has been described as an example. However, this does not have to be the case. For example, a two-phase AC power supply may be used as a power source. In this case, the switching unit has two sets of switching elements. Further, the current detection unit of the abnormality detection device has two current detection units corresponding to two sets of switching elements.

(3) Further, in the above-described embodiment, a mode in which a large current is passed through two heaters as loads has been described as an example. However, this does not have to be the case. For example, as the load, an electric device other than the heater may be used, and the current flowing through the load does not have to be a large value exceeding 1000 A.

The present invention can be widely applied as an abnormality detection device for a large current circuit and a large current circuit device.

1 Heat treatment equipment (large current circuit equipment)
4 Abnormality detection device 5 AC power supply 6 Large current circuit 9 Switching section 10 Primary side current path (current path between the switching section and the primary side of the transformer)
11 Transformer 13R, 13T, 13S Switching element 17M Secondary coil (first system)
17T secondary coil (second system)
18MM seat heater (load, first load)
18TT seat heater (load, second load)
21 Current detection unit 22 Abnormality determination unit 25R, 25T, 25S Current detection element 27 Disconnection determination unit 28 Deterioration determination unit cR, cT, cS Current detection value ThM1, ThT1 Threshold

Claims (6)

The above-mentioned in a large current circuit having a switching unit that controls the on / off of power supply from an AC power supply, and a transformer that steps down the power from the switching unit and supplies the power on the secondary side of the transformer to the load. A current detection unit that detects the current value in the current path between the switching unit and the primary side of the transformer, and a current detection unit.
An abnormality determination unit that determines the presence or absence of an abnormality on the secondary side of the large current circuit using the current detection value of the current detection unit.
Equipped with
The AC power supply is a three-phase AC power supply.
The switching unit includes three sets of switching elements corresponding to each phase from the three-phase AC power supply.
The current detecting unit includes three current detecting elements provided corresponding to each of the three sets of the switching elements and detecting the current flowing through the corresponding set of the switching elements.
The abnormality determination unit determines the presence or absence of the abnormality by using the current detection value in each of the three current detection elements.
The abnormality determination unit includes a disconnection determination unit.
The disconnection determination unit Rukoto to determine whether using the ratio between the maximum value and the minimum value of three of the current detection values detected by the three of the current detecting element, disconnection to the load is generated Anomaly detection device for large current circuits. The abnormality detection device for a large current circuit according to claim 1.
The disconnection determination unit is an abnormality detection device for a large current circuit, characterized in that, when the ratio is less than a predetermined threshold value, it is determined that the load is disconnected. The abnormality detection device for a large current circuit according to claim 1.
The abnormality determination unit is characterized in that it determines the presence or absence of the abnormality based on the deviation between the current value and the current detection value when no abnormality has occurred in the large current circuit. Anomaly detector. A failure detection device for a large-current circuit according to any one of claims 1 to 3,
The abnormality determination unit includes a deterioration determination unit.
The deterioration determination unit determines whether or not the load has deteriorated based on the degree of decrease from the time when no abnormality is detected for the three current detection values detected by the three current detection elements. Anomaly detection device for large current circuits, characterized by The abnormality detection device for a large current circuit according to any one of claims 1 to 4.
The transformer includes a Scott transformer.
The load includes a first load connected to a first system on the secondary side of the Scott transformer and a second load connected to a second system on the secondary side of the Scott transformer.
The abnormality determination unit is an abnormality detection device for a large current circuit, characterized in that it determines the presence or absence of an abnormality in each of the first load and the second load. A switching unit that controls the on / off of the power supply from the AC power supply, and a large current circuit that includes a transformer that steps down the power from this switching unit.
The load to which the power of the secondary side of the transformer is applied and
The abnormality detection device for a large current circuit according to any one of claims 1 to 5.
A high current circuit device characterized by being equipped with.

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