Abnormality detection circuit and abnormality detection method

Abstract

Provided are an abnormality detection circuit and an abnormality detection method that can detect abnormalities with high accuracy. The abnormality detection circuit includes an alternating-current power supply connected to a load via first and second lines, a first relay contact disposed midway through the first line, a second relay contact disposed midway through the second line, a comparison voltage detection circuit that applies a voltage from the alternating-current power supply regardless of the open / close state of the first and second relay contacts, a first voltage detection circuit that applies a voltage from the alternating-current power supply when the first relay contact is in a closed state, a second voltage detection circuit that applies a voltage from the alternating-current power supply when the second relay contact is in a closed state, and an abnormality detection unit that detects an abnormality in the first relay contact by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit and detects an abnormality in the second relay contact by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to an abnormality detection circuit and an abnormality detection method. BACKGROUND

[0002] In Patent Document 1, a relay contact abnormality detection circuit is disclosed which is configured with an optical coupler, and based on a current detected from the optical coupler, it is possible to detect welding of a contact.

[0003] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 7-296695

[0004] However, in many cases, a capacitor for the purpose of noise reduction is connected in an electrical circuit. In such a case, even in a state in which a contact is open, a voltage is applied from the capacitor to the optical coupler, and a current flowing in the optical coupler and opening and closing of the relay become unable to correspond. Therefore, there is a concern that it is not possible to detect welding of a contact with high precision. SUMMARY

[0005] An abnormality detection circuit of the present application has:

[0006] an alternating-current power supply connected to a load via a first wiring and a second wiring;

[0007] a first relay contact provided midway in the first wiring;

[0008] a second relay contact provided midway in the second wiring;

[0009] a comparison voltage detection circuit which applies a voltage from the alternating-current power supply regardless of an open / close state of the first relay contact and the second relay contact;

[0010] a first voltage detection circuit which applies a voltage from the alternating-current power supply when the first relay contact is in a closed state;

[0011] a second voltage detection circuit which applies a voltage from the alternating-current power supply when the second relay contact is in a closed state; and

[0012] an abnormality detection section which detects an abnormality of the first relay contact by comparing a voltage applied to the comparison voltage detection circuit with a voltage applied to the first voltage detection circuit, and detects an abnormality of the second relay contact by comparing a voltage applied to the comparison voltage detection circuit with a voltage applied to the second voltage detection circuit.

[0013] An abnormality detection circuit of the present application has:

[0014] an alternating-current power supply connected to a load via a first wiring and a second wiring;

[0015] a first relay contact point arranged midway in the first wiring;

[0016] a second relay contact point arranged midway in the second wiring;

[0017] a comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point;

[0018] a first voltage detection circuit connected between the first wiring on the side closer to the load than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying the same voltage as the comparison voltage detection circuit when the first relay contact point is in the closed state;

[0019] a second voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the load than the second relay contact point, and applying the same voltage as the comparison voltage detection circuit when the second relay contact point is in the closed state;

[0020] an abnormality detection unit detecting an abnormality of the first relay contact point by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit, and detecting an abnormality of the second relay contact point by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0021] The abnormality detection circuit of the present application has:

[0022] an AC power source connected to a load via first and second wirings;

[0023] a first relay contact point arranged midway in the first wiring;

[0024] a second relay contact point arranged midway in the second wiring;

[0025] a first comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point;

[0026] a second comparison voltage detection circuit connected between the first wiring on the side of the AC power source further than the first relay contact and the second wiring on the side of the AC power source further than the second relay contact in a reverse manner to the first comparison voltage detection circuit, and applying a voltage from the AC power source regardless of the open / close states of the first relay contact and the second relay contact;

[0027] a first voltage detection circuit connected between the first wiring on the side of the load further than the first relay contact and the second wiring on the side of the AC power source further than the second relay contact, and applying the same voltage as the first comparison voltage detection circuit when the first relay contact is in the closed state;

[0028] a second voltage detection circuit connected between the first wiring on the side of the AC power source further than the first relay contact and the second wiring on the side of the load further than the second relay contact, and applying the same voltage as the second comparison voltage detection circuit when the second relay contact is in the closed state; and

[0029] an abnormality detection section detecting an abnormality of the first relay contact by comparing the voltage applied to the first comparison voltage detection circuit with the voltage applied to the first voltage detection circuit, and detecting an abnormality of the second relay contact by comparing the voltage applied to the second comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0030] The abnormality detection circuit of the present application has:

[0031] an AC power source connected to a load via a first wiring and a second wiring;

[0032] a first relay contact provided midway in the first wiring;

[0033] a second relay contact provided midway in the second wiring;

[0034] a comparison voltage detection circuit connected between the first wiring on the side of the AC power source further than the first relay contact and the second wiring on the side of the AC power source further than the second relay contact, and applying a voltage from the AC power source regardless of the open / close states of the first relay contact and the second relay contact;

[0035] a first voltage detection circuit connected between the first wiring on the side of the load further than the first relay contact and the second wiring on the side of the load further than the second relay contact, and applying the same voltage as the comparison voltage detection circuit when the first relay contact and the second relay contact are in the closed state;

[0036] a second voltage detection circuit connected between the first wiring on the side of the AC power source further than the first relay contact and the second wiring on the side of the load further than the second relay contact, and applying the same voltage as the comparison voltage detection circuit when the second relay contact is in the closed state;

[0037] an abnormality detection section detecting an abnormality of the first relay contact by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit, and detecting an abnormality of the second relay contact by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0038] In the abnormality detection method of the present application, a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit are provided to a circuit having:

[0039] an AC power source connected to a load via a first wiring and a second wiring;

[0040] a first relay contact provided in the middle of the first wiring; and

[0041] a second relay contact provided in the middle of the second wiring,

[0042] the comparison voltage detection circuit applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact,

[0043] the first voltage detection circuit applying a voltage from the AC power source when the first relay contact is in the closed state;

[0044] the second voltage detection circuit applying a voltage from the AC power source when the second relay contact is in the closed state,

[0045] an abnormality of the first relay contact is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit,

[0046] an abnormality of the second relay contact is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0047] In the abnormality detection method of the present application, a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit are provided to a circuit having:

[0048] an AC power source connected to a load via a first wiring and a second wiring;

[0049] a first relay contact point arranged in the middle of the first wiring; and

[0050] a second relay contact point arranged in the middle of the second wiring,

[0051] the comparison voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact point and the second wiring on the side of the AC power source closer to the second relay contact point, and applies a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point,

[0052] the first voltage detection circuit is connected between the first wiring on the side of the load closer to the first relay contact point and the second wiring on the side of the AC power source closer to the second relay contact point, and applies the same voltage as the comparison voltage detection circuit when the first relay contact point is in the closed state,

[0053] the second voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact point and the second wiring on the side of the load closer to the second relay contact point, and applies the same voltage as the comparison voltage detection circuit when the second relay contact point is in the closed state,

[0054] an abnormality of the first relay contact point is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit,

[0055] an abnormality of the second relay contact point is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0056] In the abnormality detection method of the present application, a first comparison voltage detection circuit, a second comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit are arranged in a circuit having:

[0057] an AC power source connected to a load via a first wiring and a second wiring;

[0058] a first relay contact point arranged in the middle of the first wiring; and

[0059] a second relay contact point arranged in the middle of the second wiring,

[0060] the first comparison voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact point and the second wiring on the side of the AC power source closer to the second relay contact point, and applies a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point,

[0061] The second comparison voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact and the second wiring on the side of the AC power source closer to the second relay contact in a reverse manner to the first comparison voltage detection circuit, and applies a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact,

[0062] The first voltage detection circuit is connected between the first wiring on the side of the load closer to the first relay contact and the second wiring on the side of the AC power source closer to the second relay contact, and applies the same voltage as the first comparison voltage detection circuit when the first relay contact is in the closed state,

[0063] The second voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact and the second wiring on the side of the load closer to the second relay contact, and applies the same voltage as the second comparison voltage detection circuit when the second relay contact is in the closed state,

[0064] An abnormality of the first relay contact is detected by comparing the voltage applied to the first comparison voltage detection circuit with the voltage applied to the first voltage detection circuit,

[0065] An abnormality of the second relay contact is detected by comparing the voltage applied to the second comparison voltage detection circuit with the voltage applied to the second voltage detection circuit.

[0066] In the abnormality detection method of the present application, a circuit is configured with a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit, the circuit having:

[0067] an AC power source connected to a load via a first wiring and a second wiring;

[0068] a first relay contact disposed midway on the first wiring; and

[0069] a second relay contact disposed midway on the second wiring,

[0070] The comparison voltage detection circuit is connected between the first wiring on the side of the AC power source closer to the first relay contact and the second wiring on the side of the AC power source closer to the second relay contact in a reverse manner to the first comparison voltage detection circuit, and applies a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact,

[0071] The first voltage detection circuit is connected between the first wiring on the load side of the first relay contact and the second wiring on the load side of the second relay contact, and applies the same voltage as the comparison voltage detection circuit when the first relay contact and the second relay contact are in the closed state.

[0072] The second voltage detection circuit is connected between the first wiring on the AC power source side of the first relay contact and the second wiring on the load side of the second relay contact, and applies the same voltage as the comparison voltage detection circuit when the second relay contact is in the closed state.

[0073] An abnormality of the first relay contact is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the first voltage detection circuit.

[0074] An abnormality of the second relay contact is detected by comparing the voltage applied to the comparison voltage detection circuit with the voltage applied to the second voltage detection circuit. BRIEF DESCRIPTION OF DRAWINGS

[0075] Figure 1 FIG. 1 is a circuit diagram showing an abnormality detection circuit according to a first embodiment.

[0076] Figure 2 FIG. 2 is a table showing an abnormality detection method of a first relay.

[0077] Figure 3 FIG. 3 is a table showing an abnormality detection method of a first relay.

[0078] Figure 4 FIG. 4 is a table showing an abnormality detection method of a second relay.

[0079] Figure 5 FIG. 5 is a table showing an abnormality detection method of a second relay.

[0080] Figure 6 FIG. 6 is a circuit diagram showing a problem point of the abnormality detection circuit according to the first embodiment.

[0081] Figure 7 FIG. 7 is a circuit diagram showing an abnormality detection circuit according to a second embodiment.

[0082] Figure 8 FIG. 8 is a table showing an abnormality detection method of a first relay.

[0083] Figure 9 FIG. 9 is a table showing an abnormality detection method of a second relay.

[0084] Figure 10is a circuit diagram showing an abnormality detection circuit according to the third embodiment.

[0085] Figure 11 is a table showing an abnormality detection method of the first relay.

[0086] Figure 12 is a table showing an abnormality detection method of the second relay.

[0087] Explanation of Reference Numerals

[0088] 1 … abnormality detection circuit, 10 … load, 10A … motor drive circuit, 2 … AC power supply, 31 … first wiring, 32 … second wiring, 33 … connection wiring, 33A … connection wiring, 33B … connection wiring, 34 … connection wiring, 35 … connection wiring, 41 … first relay, 411 … first relay contact, 412 … first relay coil, 42 … second relay, 421 … second relay contact, 422 … second relay coil, 5 … control device, 51 … abnormality detection section, 6 … comparison voltage detection circuit, 6A … first comparison voltage detection circuit, 6B … second comparison voltage detection circuit, 60 … optocoupler, 60A … optocoupler, 60B … optocoupler, 61 … light emitting diode, 61A … light emitting diode, 61B … light emitting diode, 62 … phototransistor, 62A … phototransistor, 62B … phototransistor, 7 … first voltage detection circuit, 70 … optocoupler, 71 … light emitting diode, 72 … phototransistor, 8 … second voltage detection circuit, 80 … optocoupler, 81 … light emitting diode, 82 … phototransistor, 9 … bridge diode, C … capacitor, C1 … capacitor, C2 … capacitor, M … motor, P … bus, V0 … voltage, V0a … voltage, V0b … voltage, V1 … voltage, V2 … voltage. DETAILED DESCRIPTION

[0089] Hereinafter, the embodiments will be described with reference to the drawings.

[0090] First Embodiment

[0091] Figure 1 is a circuit diagram showing an abnormality detection circuit according to the first embodiment. Figure 2 and Figure 3 is a table showing an abnormality detection method of the first relay. Figure 4 and Figure 5 is a table showing an abnormality detection method of the second relay.

[0092] Figure 1The illustrated abnormality detection circuit 1 is a circuit capable of detecting abnormality of the first relay 41 and the second relay 42 that control application of voltage to the load 10. As the load 10, there is no particular limitation, but in the present embodiment, it is a motor drive circuit 10A for controlling driving of a motor M.

[0093] The abnormality detection circuit 1 has an alternating-current power supply 2 that outputs single-layer alternating current, a bridge diode 9, a first wire 31 and a second wire 32 that are a pair of wires connecting the alternating-current power supply 2 and the bridge diode 9, the first relay 41 disposed midway of the first wire 31, the second relay 42 disposed midway of the second wire 32, and a control device 5 that controls driving of each part of the abnormality detection circuit 1. The single-layer alternating current output from the alternating-current power supply 2 is supplied to the motor drive circuit 10A after being rectified to substantially smooth direct current by the bridge diode 9. As the use of the motor M, there is no particular limitation, but in the present embodiment, it is assumed to be joint driving for an industrial robot such as a SCARA robot, a 6-axis multi-joint robot, a dual-arm robot, and the like.

[0094] The first relay 41 has a first relay contact 411 disposed midway of the first wire 31, and a first relay coil 412 disposed in the vicinity of the first relay contact 411. When power is supplied to the first relay coil 412, the first relay contact 411 is closed by magnetic action to become a "closed state". On the contrary, when the supply of power to the first relay coil 412 is stopped, the magnetic action disappears and the first relay contact 411 is opened to become an "open state". Here, as the configuration of the first relay 41, there is no particular limitation if the opening and closing of the first relay contact 411 can be performed. For example, the first relay 41 can also become a closed state when power is supplied to the first relay coil 412, and become an open state when the supply of power is stopped. In addition, the first relay contact 411 can also be opened and closed by a force other than magnetism.

[0095] The second relay 42 is of the same configuration as the first relay 41. The second relay 42 has a second relay contact 421 disposed midway of the second wire 32, and a second relay coil 422 disposed in the vicinity of the second relay contact 421. When power is supplied to the second relay coil 422, the second relay contact 421 is closed by magnetic action to become a "closed state". On the contrary, when the supply of power to the second relay coil 422 is stopped, the magnetic action disappears and the second relay contact 421 is opened to become an "open state". Here, as the configuration of the second relay 42, there is no particular limitation if the opening and closing of the second relay contact 421 can be performed. For example, the second relay 42 can also become a closed state when power is supplied to the second relay coil 422, and become an open state when the supply of power is stopped. In addition, the second relay contact 421 can also be opened and closed by a force other than magnetism.

[0096] In the abnormality detection circuit 1, the power is supplied from the AC power supply 2 to the motor drive circuit 10A when both the first relay 41 and the second relay 42 are in the closed state, and the power is not supplied from the AC power supply 2 to the motor drive circuit 10A when at least one of the first relay 41 and the second relay 42 is in the open state.

[0097] The bridge diode 9 is a bridge connection of four diodes, and converts and rectifies a negative voltage amount of an input voltage to a positive voltage to be a direct current (pulsating current). Thereafter, the bridge diode 9 performs smoothing of a waveform using charge and discharge of a capacitor, and converts to a substantially flat direct current.

[0098] The abnormality detection circuit 1 further has a connection wire 33 that connects the first wire 31 on the AC power supply 2 side than the first relay contact 411 and the second wire 32 on the AC power supply 2 side than the second relay contact 421, and a comparison voltage detection circuit 6 disposed in the middle of the connection wire 33.

[0099] The comparison voltage detection circuit 6 has an optical coupler 60 including a light emitting diode 61 connected between the first wire 31 and the second wire 32, and a phototransistor 62 that receives light of the light emitting diode 61. In the comparison voltage detection circuit 6, the phototransistor 62 becomes ON when the light emitting diode 61 emits light, and outputs a voltage V0. Thus, it is possible to detect a voltage applied to the light emitting diode 61. Further, in the light emitting diode 61, the first wire 31 side is an anode, and the second wire 32 side is a cathode. Therefore, when the first wire 31 side becomes a high potential than the second wire 32 side, a voltage is applied to the light emitting diode 61, and the light emitting diode 61 emits light.

[0100] The abnormality detection circuit 1 further has a connection wire 34 that connects the first wire 31 on the bridge diode 9 side than the first relay contact 411 and the second wire 32 on the AC power supply 2 side than the second relay contact 421, and a first voltage detection circuit 7 disposed in the middle of the connection wire 34.

[0101] The first voltage detection circuit 7 is configured the same as the comparison voltage detection circuit 6. That is, the first voltage detection circuit 7 has an optocoupler 70 having a light-emitting diode 71 connected between the first wiring 31 and the second wiring 32, and a phototransistor 72 that receives light from the light-emitting diode 71. In the first voltage detection circuit 7, the phototransistor 72 becomes conductive when the light-emitting diode 71 emits light, and outputs a voltage VI. Thus, the voltage applied to the light-emitting diode 71 can be detected. Further, in the light-emitting diode 71, the first wiring 31 side is the anode, and the second wiring 32 side is the cathode. Therefore, when the first wiring 31 side becomes a high potential compared to the second wiring 32 side, a voltage is applied to the light-emitting diode 71, and the light-emitting diode 71 emits light.

[0102] The abnormality detection circuit 1 further has a connection wiring 35 connecting the first wiring 31 on the AC power supply 2 side than the first relay contact 411, and the second wiring 32 on the bridge diode 9 side than the second relay contact 421, and a second voltage detection circuit 8 disposed midway through the connection wiring 35.

[0103] The second voltage detection circuit 8 is configured the same as the comparison voltage detection circuit 6. That is, the second voltage detection circuit 8 has an optocoupler 80 having a light-emitting diode 81 connected between the first wiring 31 and the second wiring 32, and a phototransistor 82 that receives light from the light-emitting diode 81. In the second voltage detection circuit 8, the phototransistor 82 becomes conductive when the light-emitting diode 81 emits light, and outputs a voltage V2. Thus, the voltage applied to the light-emitting diode 81 can be detected. Further, in the light-emitting diode 81, the first wiring 31 side is the anode, and the second wiring 32 side is the cathode. Therefore, when the first wiring 31 side becomes a high potential compared to the second wiring 32 side, a voltage is applied to the light-emitting diode 81, and the light-emitting diode 81 emits light.

[0104] The abnormality detection circuit 1 further has a plurality of capacitors C disposed mainly for the purpose of reducing noise. Further, the number or disposition of the capacitors C is not particularly limited, and is appropriately set according to the purpose. In the embodiment, as the capacitors C, a capacitor CI connected to a contact of the first wiring 31 and the connection wiring 34, and a capacitor C2 connected to a contact of the second wiring 32 and the connection wiring 35 are disposed. Figure 1

[0105] ​The driving of each part of the abnormality detection circuit 1 is controlled by the control device 5. Specifically, the control device 5 controls the driving of the alternating-current power supply 2. In addition, the control device 5 controls the opening and closing of the first relay 41 by controlling the supply / non-supply of power to the first relay coil 412. In addition, the control device 5 controls the opening and closing of the second relay 42 by controlling the supply / non-supply of power to the second relay coil 422. In addition, the control device 5 has an abnormality detection part 51 that detects abnormalities of the first relay 41 and the second relay 42.

[0106] The control device 5 is constituted by, for example, a computer, and has a processor that processes information; a memory that is communicably connected to the processor; and an external interface that performs communication with an external device not shown. Various programs that are executable by the processor are stored in the memory, and the processor reads and executes the various programs stored in the memory and the like.

[0107] Next, the abnormality detection of the first relay 41 and the second relay 42 based on the abnormality detection part 51 will be described. In addition, the abnormality of the first relay 41 means, for example, a state in which the first relay 41 cannot be brought to the closed state even if power is supplied to the first relay coil 412 due to poor contact of the first relay contact 411 and the like, a state in which the first relay 41 cannot be brought to the open state even if the supply of power to the first relay coil 412 is stopped due to welding of the first relay contact 411 and the like, and the like. The same applies to the abnormality of the second relay 42.

[0108] First, the abnormality detection of the first relay 41 will be described. When the first relay 41 is set to the closed state by the supply of power to the first relay coil 412, a voltage is applied from the alternating-current power supply 2 to the light-emitting diode 71, and a voltage VI is output from the first voltage detection circuit 7 according to the light emission of the light-emitting diode 71. On the contrary, even if the first relay 41 is set to the open state by stopping the supply of power to the first relay coil 412, a voltage is applied to the light-emitting diode 71 by the charge and discharge of the capacitor C, and a voltage VI is output from the first voltage detection circuit 7 according to the light emission of the light-emitting diode 71. That is, in the abnormality detection circuit 1, a voltage VI is output from the first voltage detection circuit 7 regardless of the open / close state of the first relay 41. Therefore, the abnormality of the first relay 41 cannot be determined by the combination of the supply / non-supply of power to the first relay coil 412 and the presence / absence of output of the voltage VI as shown in FIG. 6. Figure 2

[0109] ​Therefore, in the anomaly detection circuit 1, a comparison voltage detection circuit 6 is provided. An anomaly in the first relay 41 is detected by comparing the voltage V0 output from the comparison voltage detection circuit 6 with the voltage V1 output from the first voltage detection circuit 7. In the anomaly detection circuit 1, regardless of the open or closed state of the first relay 41, a voltage is applied from the AC power supply 2 to the light-emitting diode 61, and the comparison voltage detection circuit 6 outputs the corresponding voltage V0. Furthermore, in the anomaly detection circuit 1, regardless of the open or closed state of the first relay 41, a voltage is applied to the light-emitting diode 71, and the first voltage detection circuit 7 outputs the corresponding voltage V1. Thus, both the comparison voltage detection circuit 6 and the first voltage detection circuit 7 output voltages V0 and V1 corresponding to the applied voltages, regardless of the open or closed state of the first relay 41.

[0110] However, depending on the opening and closing state of the first relay 41, the duty cycle difference or phase difference of voltages V0 and V1 changes. For example... Figure 3 As shown, when the first relay 41 is closed, voltages are applied to LEDs 61 and 71 from the AC power supply 2. That is, the same voltage is applied to LEDs 61 and 71. Therefore, no duty cycle difference or phase difference is generated between voltages V0 and V1. Furthermore, the term "same voltage" means, in addition to the same voltage, that includes cases where there may be some differences due to circuit configuration. Similarly, the term "no duty cycle difference or phase difference" means, in addition to the case where the difference is zero, that includes cases where there may be some differences due to circuit configuration. In contrast, when the first relay 41 is open, voltage is applied to LED 61 from the AC power supply 2, and voltage is applied to LED 71 by the charging and discharging of capacitor C. Therefore, a voltage that is attenuated and phase-biased relative to the voltage applied to LED 61 is applied to LED 71. This results in a duty cycle difference and a phase difference between voltages V0 and V1.

[0111] Therefore, the anomaly detection unit 51 detects an anomaly in the first relay 41 based on at least one of the duty cycle difference and phase difference of voltages V0 and V1.

[0112] In the case of detecting the abnormality of the first relay 41 based on the phase difference of the voltages V0, V1, the abnormality detecting section 51 determines that "the first relay 41 is normal" in the case where the voltages V0, V1 are the same phase (including the case where the phase difference is less than the threshold value) in the state where the first relay coil 412 is supplied with power, or in the case where the threshold value or more of the phase difference is generated between the voltages V0, V1 in the state where the first relay coil 412 is not supplied with power. In contrast, the abnormality detecting section 51 determines that "the first relay 41 is abnormal" in the case where the threshold value or more of the phase difference is generated between the voltages V0, V1 in the state where the first relay coil 412 is supplied with power, or in the case where the voltages V0, V1 are the same phase in the state where the first relay coil 412 is not supplied with power.

[0113] In the case of detecting the abnormality of the first relay 41 based on the duty cycle difference of the voltages V0, V1, the abnormality detecting section 51 determines that "the first relay 41 is normal" in the case where the duty cycles of the voltages V0, V1 are the same (including the case where the duty cycle difference is less than the threshold value) in the state where the first relay coil 412 is supplied with power, or in the case where the threshold value or more of the duty cycle difference is generated between the voltages V0, V1 in the state where the first relay coil 412 is not supplied with power. In contrast, the abnormality detecting section 51 determines that "the first relay 41 is abnormal" in the case where the threshold value or more of the duty cycle difference is generated between the voltages V0, V1 in the state where the first relay coil 412 is supplied with power, or in the case where the duty cycles of the voltages V0, V1 are the same in the state where the first relay coil 412 is not supplied with power.

[0114] Thus, according to the abnormality detecting method based on the duty cycle difference or the phase difference of the voltages V0, V1, the abnormality of the first relay 41 can be detected with high accuracy in the circuit that applies the voltage to the first voltage detecting circuit 7, regardless of the on-off state of the first relay 41.

[0115] Next, the abnormality detection of the second relay 42 will be described. The abnormality detection method of the second relay 42 is the same as the above-described abnormality detection method of the first relay 41. When the second relay 42 is set to the on state by the supply of power to the second relay coil 422, the voltage is applied to the light emitting diode 81 from the alternating current power supply 2, and the voltage V2 is output from the second voltage detecting circuit 8 according to the light emission of the light emitting diode 81. In contrast, when the second relay 42 is set to the off state by the stop of the supply of power to the second relay coil 422, the voltage is applied to the light emitting diode 81 by the charge and discharge of the capacitor C, and the voltage V2 is output from the second voltage detecting circuit 8 according to the light emission of the light emitting diode 81. That is, in the abnormality detecting circuit 1, the voltage V2 is output from the second voltage detecting circuit 8 regardless of the on-off state of the second relay 42. Therefore, it is not possible to detect the abnormality of the second relay 42 based on the voltage V2. Figure 4The abnormality of the second relay 42 is determined by the combination of power supply / non-power supply to the second relay coil 422 and the presence / absence of voltage V2 output.

[0116] Therefore, in the anomaly detection circuit 1, a comparison voltage detection circuit 6 is provided. Anomalies in the second relay 42 are detected by comparing the voltage V0 output from the comparison voltage detection circuit 6 with the voltage V2 output from the second voltage detection circuit 8. In the anomaly detection circuit 1, regardless of the open or closed state of the second relay 42, a voltage is applied from the AC power supply 2 to the light-emitting diode 61, and the comparison voltage detection circuit 6 outputs the corresponding voltage V0. Furthermore, in the anomaly detection circuit 1, regardless of the open or closed state of the second relay 42, a voltage is applied to the light-emitting diode 81, and the second voltage detection circuit 8 outputs the corresponding voltage V2. Thus, both the comparison voltage detection circuit 6 and the second voltage detection circuit 8 output voltages V0 and V2 regardless of the open or closed state of the second relay 42.

[0117] However, depending on the opening and closing state of the second relay 42, the duty cycle difference and phase difference of voltages V0 and V2 change. For example... Figure 5 As shown, when the second relay 42 is closed, voltages are applied from the AC power supply 2 to LEDs 61 and 81 respectively. That is, the same voltage is applied to LEDs 61 and 81. Therefore, no duty cycle difference or phase difference is generated between voltages V0 and V2. In contrast, when the second relay 42 is closed, voltage is applied from the AC power supply 2 to LED 61, and voltage is applied to LED 81 by the charging and discharging of capacitor C. Therefore, a voltage that is attenuated and phase-shifted relative to the voltage applied to LED 61 is applied to LED 81. As a result, a duty cycle difference and a phase difference are generated between voltages V0 and V2.

[0118] Therefore, the anomaly detection unit 51 detects the anomaly of the second relay 42 based on at least one of the duty cycle difference and phase difference of voltages V0 and V2.

[0119] When detecting abnormalities in the second relay 42 based on the phase difference between voltages V0 and V2, if voltages V0 and V2 are in phase (including cases where the phase difference is less than a threshold) when the abnormality detection unit 51 is supplying power to the second relay coil 422, or if a phase difference exceeding the threshold occurs between voltages V0 and V2 when power is not supplied to the second relay coil 422, the unit determines that "the second relay 42 is normal". Conversely, if a phase difference exceeding the threshold occurs between voltages V0 and V2 when power is supplied to the second relay coil 422, or if voltages V0 and V2 are in phase when power is not supplied to the second relay coil 422, the unit determines that "the second relay 42 is abnormal".

[0120] In the case where the abnormality of the second relay 42 is detected based on the duty ratio difference of the voltages V0, V2, the abnormality detection section 51 determines that "the second relay 42 is normal" in the case where the duty ratios of the voltages V0, V2 are the same (including the case where the duty ratio difference is smaller than the threshold value) in the state where the second relay coil 422 is supplied with power, or in the case where the duty ratio difference of the voltages V0, V2 is larger than the threshold value in the state where the second relay coil 422 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the second relay 42 is abnormal" in the case where the duty ratio difference of the voltages V0, V2 is larger than the threshold value in the state where the second relay coil 422 is supplied with power, or in the case where the duty ratios of the voltages V0, V2 are the same in the state where the second relay coil 422 is not supplied with power.

[0121] Thus, according to the abnormality detection method based on the duty ratio difference or the phase difference of the voltages V0, V2, the abnormality of the second relay 42 can be detected with high accuracy in the circuit in which the voltage is applied to the second voltage detection circuit 8, regardless of the on-off state of the second relay 42.

[0122] The abnormality detection circuit 1 and the abnormality detection method have been described above. As described above, such an abnormality detection circuit 1 has: an alternating-current power supply 2 connected to a load 10 via a first wiring 31 and a second wiring 32; a first relay contact 411 disposed in the middle of the first wiring 31; a second relay contact 421 disposed in the middle of the second wiring 32; a comparison voltage detection circuit 6 to which a voltage is applied from the alternating-current power supply 2 regardless of the on-off state of the first relay contact 411 and the second relay contact 421; a first voltage detection circuit 7 to which a voltage is applied from the alternating-current power supply 2 when the first relay contact 411 is in the closed state; a second voltage detection circuit 8 to which a voltage is applied from the alternating-current power supply 2 when the second relay contact 421 is in the closed state; and an abnormality detection section 51 that detects an abnormality of the first relay contact 411 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7, and that detects an abnormality of the second relay contact 421 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0123] According to such a configuration, the abnormality of the first relay contact 411 can be detected with high accuracy in the circuit in which the voltage is applied to the first voltage detection circuit 7, regardless of the on-off state of the first relay 41. In addition, the abnormality of the second relay contact 421 can be detected with high accuracy in the circuit in which the voltage is applied to the second voltage detection circuit 8, regardless of the on-off state of the second relay 42.

[0124] Further, as described above, the abnormality detection circuit 1 has the AC power supply 2 connected with the load 10 via the first wiring 31 and the second wiring 32, the first relay contact 411 disposed in the middle of the first wiring 31, the second relay contact 421 disposed in the middle of the second wiring 32, the comparison voltage detection circuit 6 connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, which applies a voltage from the AC power supply 2 regardless of the opening and closing states of the first relay contact 411 and the second relay contact 421, the first voltage detection circuit 7 connected between the first wiring 31 on the load 10 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, which applies the same voltage as the comparison voltage detection circuit 6 when the first relay contact 411 is in the closed state, the second voltage detection circuit 8 connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the load 10 side than the second relay contact 421, which applies the same voltage as the comparison voltage detection circuit 6 when the second relay contact 421 is in the closed state, and the abnormality detection section 51 that detects an abnormality of the first relay contact 411 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7 and detects an abnormality of the second relay contact 421 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0125] According to such a configuration, regardless of the opening and closing state of the first relay 41, an abnormality of the first relay contact 411 can be detected with high precision in the circuit in which the voltage is applied to the first voltage detection circuit 7. Further, regardless of the opening and closing state of the second relay 42, an abnormality of the second relay contact 421 can be detected with high precision in the circuit in which the voltage is applied to the second voltage detection circuit 8.

[0126] Further, in the abnormality detection method, the circuit configured with the comparison voltage detection circuit 6, the first voltage detection circuit 7, and the second voltage detection circuit 8, the circuit having the alternating current power supply 2 connected to the load 10 via the first wiring 31 and the second wiring 32, the first relay contact 411 configured at the middle of the first wiring 31, and the second relay contact 421 configured at the middle of the second wiring 32, the comparison voltage detection circuit 6 applying voltage from the alternating current power supply 2 regardless of the open / close state of the first relay contact 411 and the second relay contact 421, the first voltage detection circuit 7 applying voltage from the alternating current power supply 2 when the first relay contact 411 is in the closed state, and the second voltage detection circuit 8 applying voltage from the alternating current power supply 2 when the second relay contact 421 is in the closed state, detects the abnormality of the first relay contact 411 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7, and detects the abnormality of the second relay contact 421 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0127] According to such a method, the abnormality of the first relay contact 411 can be detected with high precision in the circuit in which voltage is applied to the first voltage detection circuit 7 regardless of the open / close state of the first relay 41. Further, the abnormality of the second relay contact 421 can be detected with high precision in the circuit in which voltage is applied to the second voltage detection circuit 8 regardless of the open / close state of the second relay 42.

[0128] Further, in the abnormality detection method, the circuit is configured with the comparison voltage detection circuit 6, the first voltage detection circuit 7, and the second voltage detection circuit 8, the circuit having the AC power supply 2 connected to the load 10 via the first wiring 31 and the second wiring 32, the first relay contact 411 disposed in the middle of the first wiring 31, and the second relay contact 421 disposed in the middle of the second wiring 32, the comparison voltage detection circuit 6 being connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, the voltage being applied from the AC power supply 2 regardless of the open / close state of the first relay contact 411 and the second relay contact 421, the first voltage detection circuit 7 being connected between the first wiring 31 on the load 10 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, the same voltage as the comparison voltage detection circuit 6 being applied when the first relay contact 411 is in the closed state, the second voltage detection circuit 8 being connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the load 10 side than the second relay contact 421, the same voltage as the comparison voltage detection circuit 6 being applied when the second relay contact 421 is in the closed state, the abnormality of the first relay contact 411 being detected by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7, and the abnormality of the second relay contact 421 being detected by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0129] According to such a method, the abnormality of the first relay contact 411 can be detected with high accuracy in the circuit in which the voltage is applied to the first voltage detection circuit 7 regardless of the open / close state of the first relay 41. Further, the abnormality of the second relay contact 421 can be detected with high accuracy in the circuit in which the voltage is applied to the second voltage detection circuit 8 regardless of the open / close state of the second relay 42.

[0130] Second Embodiment

[0131] Figure 6 is a circuit diagram showing a point of the abnormality detection circuit according to the first embodiment. Figure 7 is a circuit diagram showing a point of the abnormality detection circuit according to the second embodiment. Figure 8 is a table showing the abnormality detection method of the first relay. Figure 9 is a table showing the abnormality detection method of the second relay.

[0132] This embodiment is the same as the first embodiment described above, except that the configurations of the comparison voltage detection circuit 6 and the first voltage detection circuit 7 are different. In the following description, this embodiment will be described primarily for its differences from the embodiments described above, and descriptions of identical items will be omitted. Furthermore, in Figures 6 to 9 In this drawing, the same reference numerals are used to indicate configurations that are the same as those described in the embodiments above.

[0133] like Figure 6 As shown, in the anomaly detection circuit 1 of the first embodiment described above, a bus P is formed when the first relay 41 and the second relay 42 are in the on state. The photocurrent level in bus P is extremely small, thus unlikely to cause significant problems, but it is preferable not to form it. Therefore, in this embodiment, as... Figure 7 As shown, the first voltage detection circuit 7 is configured in the opposite direction to the first embodiment described above. That is, in the light-emitting diode 71, the side with the second wiring 32 is the anode, and the side with the first wiring 31 is the cathode. Therefore, the formation of the bus P can be prevented with a simple configuration.

[0134] In this embodiment, the light-emitting diode 71 of the first voltage detection circuit 7 is oriented in the opposite direction to the light-emitting diode 81 of the second voltage detection circuit 8. Therefore, the comparison voltage detection circuit 6 has: a first comparison voltage detection circuit 6A for comparison with the first voltage detection circuit 7; and a second comparison voltage detection circuit 6B for comparison with the second voltage detection circuit 8.

[0135] The first comparison voltage detection circuit 6A includes an optocoupler 60A, which comprises: a light-emitting diode (LED) 61A disposed midway in a connecting wire 33A connecting the first wire 31 and the second wire 32; and a phototransistor 62A that receives light from the LED 61A. In this first comparison voltage detection circuit 6A, when the LED 61A emits light, the phototransistor 62A becomes conductive and outputs a voltage V0a. Thus, the voltage applied to the LED 61A can be detected. Furthermore, in the LED 61A, the second wire 32 side is the anode, and the first wire 31 side is the cathode. Therefore, when the second wire 32 side is at a higher potential than the first wire 31 side, a voltage is applied to the LED 61A, causing the LED 61A to emit light.

[0136] The second comparison voltage detection circuit 6B is configured in the same manner as the first comparison voltage detection circuit 6A, but in the opposite direction. That is, the second comparison voltage detection circuit 6B has an optocoupler 60B having a light-emitting diode 61B disposed midway through the connection line 33B connecting the first line 31 and the second line 32, and a phototransistor 62B receiving light from the light-emitting diode 61B. In this second comparison voltage detection circuit 6B, the phototransistor 62B is turned on and outputs a voltage VOb when the light-emitting diode 61B emits light. Thus, the voltage applied to the light-emitting diode 61B can be detected. In addition, in the light-emitting diode 61B, the first line 31 side is the anode and the second line 32 side is the cathode. Thus, when the first line 31 side is at a higher potential than the second line 32 side, a voltage is applied to the light-emitting diode 61B, and the light-emitting diode 61B emits light.

[0137] Next, the abnormality detection of the first relay 41 and the second relay 42 based on the abnormality detection section 51 will be described.

[0138] First, the abnormality detection of the first relay 41 will be described. As shown in FIG. 6, the abnormality detection section 51 detects an abnormality of the first relay 41 by comparing the voltage V0a output from the first comparison voltage detection circuit 6A and the voltage V1 output from the first voltage detection circuit 7. Figure 8

[0139] Specifically, as with the first embodiment described above, the abnormality detection section 51 detects an abnormality of the first relay 41 based on at least one of the duty cycle difference and the phase difference of the voltages V0a and V1.

[0140] In the case where the abnormality of the first relay 41 is detected based on the phase difference of the voltages V0a and V1, the abnormality detection section 51 determines that "the first relay 41 is normal" in the case where the voltages V0a and V1 are in the same phase (including the case where the phase difference is less than a threshold value) with the first relay coil 412 supplied with power, or in the case where a phase difference of the voltages V0a and V1 of the threshold value or more occurs with the first relay coil 412 not supplied with power. Conversely, the abnormality detection section 51 determines that "the first relay 41 is abnormal" in the case where a phase difference of the voltages V0a and V1 of the threshold value or more occurs with the first relay coil 412 supplied with power, or in the case where the voltages V0a and V1 are in the same phase with the first relay coil 412 not supplied with power.

[0141] ​In a case where the abnormality of the first relay 41 is detected based on the duty ratio difference of the voltages V0a, V1, the abnormality detection section 51 determines that "the first relay 41 is normal" in a case where the duty ratios of the voltages V0a, V1 are the same (including a case where the duty ratio difference is smaller than the threshold value) in a state where the first relay coil 412 is supplied with power, or in a case where the duty ratio difference of the voltages V0a, V1 is larger than the threshold value in a state where the first relay coil 412 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the first relay 41 is abnormal" in a case where the duty ratio difference of the voltages V0a, V1 is larger than the threshold value in a state where the first relay coil 412 is supplied with power, or in a case where the duty ratios of the voltages V0a, V1 are the same in a state where the first relay coil 412 is not supplied with power.

[0142] Thus, according to the abnormality detection method based on the duty ratio difference or the phase difference of the voltages V0a, V1, the abnormality of the first relay 41 can be detected with high precision in the circuit that applies the voltage to the first voltage detection circuit 7, regardless of the on-off state of the first relay 41.

[0143] Next, the abnormality detection of the second relay 42 will be described. As shown in FIG. 4, the abnormality detection section 51 detects the abnormality of the second relay 42 based on at least one of the duty ratio difference and the phase difference of the voltages V0b, V2. Figure 9

[0144] In a case where the abnormality of the second relay 42 is detected based on the phase difference of the voltages V0b, V2, the abnormality detection section 51 determines that "the second relay 42 is normal" in a case where the voltages V0b, V2 are the same phase (including a case where the phase difference is smaller than the threshold value) in a state where the second relay coil 422 is supplied with power, or in a case where the phase difference of the voltages V0b, V2 is larger than the threshold value in a state where the second relay coil 422 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the second relay 42 is abnormal" in a case where the phase difference of the voltages V0b, V2 is larger than the threshold value in a state where the second relay coil 422 is supplied with power, or in a case where the voltages V0b, V2 are the same phase in a state where the second relay coil 422 is not supplied with power.

[0145] ​In a case where the abnormality of the second relay 42 is detected based on the duty ratio difference of the voltages V0b, V2, the abnormality detection section 51 determines that "the second relay 42 is normal" in a case where the duty ratios of the voltages V0b, V2 are the same (including a case where the duty ratio difference is smaller than the threshold value) in a state where the second relay coil 422 is supplied with power, or in a case where the duty ratio difference of the voltages V0b, V2 is larger than the threshold value in a state where the second relay coil 422 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the second relay 42 is abnormal" in a case where the duty ratio difference of the voltages V0b, V2 is larger than the threshold value in a state where the second relay coil 422 is supplied with power, or in a case where the duty ratios of the voltages V0b, V2 are the same in a state where the second relay coil 422 is not supplied with power.

[0146] Thus, according to the abnormality detection method based on the duty ratio difference or the phase difference of the voltages V0b, V2, the abnormality of the second relay 42 can be detected with high accuracy in the circuit that applies the voltage to the second voltage detection circuit 8, regardless of the on-off state of the second relay 42.

[0147] The abnormality detection circuit 1 and the abnormality detection method have been described above. As described above, the abnormality detection circuit 1 has the AC power supply 2 connected to the load 10 via the first wiring 31 and the second wiring 32, the first relay contact 411 disposed in the middle of the first wiring 31, the second relay contact 421 disposed in the middle of the second wiring 32, the first comparison voltage detection circuit 6A connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, the voltage being applied from the AC power supply 2 regardless of the opening and closing states of the first relay contact 411 and the second relay contact 421, the second comparison voltage detection circuit 6B connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421 in a reverse manner to the first comparison voltage detection circuit 6A, the voltage being applied from the AC power supply 2 regardless of the opening and closing states of the first relay contact 411 and the second relay contact 421, the first voltage detection circuit 7 connected between the first wiring 31 on the load 10 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, the same voltage as the first comparison voltage detection circuit 6A being applied when the first relay contact 411 is in the closed state, the second voltage detection circuit 8 connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the load 10 side than the second relay contact 421, the same voltage as the second comparison voltage detection circuit 6B being applied when the second relay contact 421 is in the closed state, and the abnormality detection unit 51 detecting the abnormality of the first relay contact 411 by comparing the voltage applied to the first comparison voltage detection circuit 6A with the voltage applied to the first voltage detection circuit 7 and detecting the abnormality of the second relay contact 421 by comparing the voltage applied to the second comparison voltage detection circuit 6B with the voltage applied to the second voltage detection circuit 8.

[0148] According to such a configuration, the abnormality of the first relay contact 411 can be detected with high accuracy in the circuit in which the voltage is applied to the first voltage detection circuit 7 regardless of the opening and closing states of the first relay 41. Also, the abnormality of the second relay contact 421 can be detected with high accuracy in the circuit in which the voltage is applied to the second voltage detection circuit 8 regardless of the opening and closing states of the second relay 42.

[0149] Further, in the abnormality detection method, first comparison voltage detection circuit 6A, second comparison voltage detection circuit 6B, first voltage detection circuit 7, and second voltage detection circuit 8 are provided to the circuit having: AC power supply 2 connected to load 10 via first wiring 31 and second wiring 32; first relay contact 411 provided in the middle of first wiring 31; second relay contact 421 provided in the middle of second wiring 32, first comparison voltage detection circuit 6A connected between first wiring 31 on the AC power supply 2 side than first relay contact 411 and second wiring 32 on the AC power supply 2 side than second relay contact 421, voltage applied from AC power supply 2 regardless of the open / close state of first relay contact 411 and second relay contact 421, second comparison voltage detection circuit 6B connected between first wiring 31 on the AC power supply 2 side than first relay contact 411 and second wiring 32 on the AC power supply 2 side than second relay contact 421 in a reverse manner to first comparison voltage detection circuit 6A, voltage applied from AC power supply 2 regardless of the open / close state of first relay contact 411 and second relay contact 421, first voltage detection circuit 7 connected between first wiring 31 on the load 10 side than first relay contact 411 and second wiring 32 on the AC power supply 2 side than second relay contact 421, same voltage as first comparison voltage detection circuit 6A applied when first relay contact 411 is in the closed state, and second voltage detection circuit 8 connected between first wiring 31 on the AC power supply 2 side than first relay contact 411 and second wiring 32 on the load 10 side than second relay contact 421, same voltage as second comparison voltage detection circuit 6B applied when second relay contact 421 is in the closed state, abnormality of first relay contact 411 detected by comparing the voltage applied to first comparison voltage detection circuit 6A with the voltage applied to first voltage detection circuit 7, and abnormality of second relay contact 421 detected by comparing the voltage applied to second comparison voltage detection circuit 6B with the voltage applied to second voltage detection circuit 8.

[0150] According to such a method, regardless of the open / close state of first relay 41, the abnormality of first relay contact 411 can be detected with high accuracy in the circuit in which voltage is applied to first voltage detection circuit 7. Further, regardless of the open / close state of second relay 42, the abnormality of second relay contact 421 can be detected with high accuracy in the circuit in which voltage is applied to second voltage detection circuit 8.

[0151] The same effects as those of the first embodiment described above can also be achieved by the second embodiment described above.

[0152] Third Embodiment

[0153] Figure 10is a circuit diagram showing an abnormality detection circuit according to a third embodiment. Figure 11 is a table showing an abnormality detection method of the first relay. Figure 12 is a table showing an abnormality detection method of the second relay.

[0154] This embodiment is the same as the above-described first embodiment except for the configuration of the first voltage detection circuit 7. In the following description, regarding this embodiment, the description is centered on the difference from the above-described embodiment, and the description is omitted for the same matters. In addition, in the following description, the same reference numerals are attached to the same configuration as the above-described embodiment. Figures 10 to 12 In the following description, the same reference numerals are attached to the same configuration as the above-described embodiment.

[0155] In the following description, the same reference numerals are attached to the same configuration as the above-described embodiment. Figure 10 In the abnormality detection circuit 1 shown in FIG. 6, the first voltage detection circuit 7 is connected between the first wiring 31 on the downstream side of the first relay contact 411 and the second wiring 32 on the downstream side of the second relay contact 421. In the abnormality detection circuit 1 of such a configuration, the abnormality of the first relay 41 and the second relay 42 is detected as follows.

[0156] First, the abnormality detection of the second relay 42 is described. As shown in FIG. 6, the abnormality detection section 51 detects the abnormality of the second relay 42 based on at least one of the duty cycle difference and the phase difference of the voltages V0, V2. Figure 11

[0157] In a case where the abnormality of the second relay 42 is detected based on the phase difference of the voltages V0, V2, the abnormality detection section 51 determines that the second relay 42 is normal in a case where the voltages V0, V2 are in the same phase with the second relay coil 422 supplied with power (including a case where the phase difference is smaller than a threshold value) or in a case where a phase difference of the voltages V0, V2 is larger than the threshold value with the second relay coil 422 not supplied with power. In contrast, the abnormality detection section 51 determines that the second relay 42 is abnormal in a case where a phase difference of the voltages V0, V2 is larger than the threshold value with the second relay coil 422 supplied with power or in a case where the voltages V0, V2 are in the same phase with the second relay coil 422 not supplied with power.

[0158] ​In the case of detecting the abnormality of the second relay 42 based on the duty ratio difference of the voltages V0, V2, the abnormality detection section 51 determines that "the second relay 42 is normal" in the case where the duty ratios of the voltages V0, V2 are the same (including the case where the duty ratio difference is smaller than the threshold value) in the state where the second relay coil 422 is supplied with power, or in the case where the duty ratio difference of the voltages V0, V2 is larger than the threshold value in the state where the second relay coil 422 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the second relay 42 is abnormal" in the case where the duty ratio difference of the voltages V0, V2 is larger than the threshold value in the state where the second relay coil 422 is supplied with power, or in the case where the duty ratios of the voltages V0, V2 are the same in the state where the second relay coil 422 is not supplied with power.

[0159] Thus, according to the abnormality detection method based on the duty ratio difference or the phase difference of the voltages V0, V2, the abnormality of the second relay 42 can be detected with high accuracy in the circuit that applies the voltages to the second voltage detection circuit 8, regardless of the on-off state of the second relay 42.

[0160] Next, the abnormality detection of the first relay 41 will be described. The abnormality detection of the first relay 41 is performed in the state where the second relay 42 is set to the closed state after it is confirmed that the second relay 42 is normal. As shown in FIG. 6, the abnormality detection section 51 detects the abnormality of the first relay 41 based on at least one of the duty ratio difference and the phase difference of the voltages V0, V1. Figure 12

[0161] In the case of detecting the abnormality of the first relay 41 based on the phase difference of the voltages V0, V1, the abnormality detection section 51 determines that "the first relay 41 is normal" in the case where the voltages V0, V1 are the same phase (including the case where the phase difference is smaller than the threshold value) in the state where the first relay coil 412 is supplied with power, or in the case where the phase difference of the voltages V0, V1 is larger than the threshold value in the state where the first relay coil 412 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the first relay 41 is abnormal" in the case where the phase difference of the voltages V0, V1 is larger than the threshold value in the state where the first relay coil 412 is supplied with power, or in the case where the voltages V0, V1 are the same phase in the state where the first relay coil 412 is not supplied with power.

[0162] ​In a case where the abnormality of the first relay 41 is detected based on the duty ratio difference of the voltages V0, V1, the abnormality detection section 51 determines that "the first relay 41 is normal" in a case where the duty ratios of the voltages V0, V1 are the same (including a case where the duty ratio difference is smaller than the threshold value) in a state where the first relay coil 412 is supplied with power, or in a case where the duty ratio difference of the voltages V0, V1 is equal to or larger than the threshold value in a state where the first relay coil 412 is not supplied with power. In contrast, the abnormality detection section 51 determines that "the first relay 41 is abnormal" in a case where the duty ratio difference of the voltages V0, V1 is equal to or larger than the threshold value in a state where the first relay coil 412 is supplied with power, or in a case where the duty ratios of the voltages V0, V1 are the same in a state where the first relay coil 412 is not supplied with power.

[0163] Thus, according to the abnormality detection method based on the duty ratio difference or the phase difference of the voltages V0, V1, the abnormality of the first relay 41 is accurately detected in the circuit that applies the voltage to the first voltage detection circuit 7, regardless of the on-off state of the first relay 41.

[0164] The abnormality detection circuit 1 and the abnormality detection method have been described above. As described above, such an abnormality detection circuit 1 includes an alternating-current power supply 2 connected to a load 10 via a first wiring 31 and a second wiring 32, a first relay contact 411 disposed in the middle of the first wiring 31, a second relay contact 421 disposed in the middle of the second wiring 32, a comparison voltage detection circuit 6 connected between the first wiring 31 on the alternating-current power supply 2 side of the first relay contact 411 and the second wiring 32 on the alternating-current power supply 2 side of the second relay contact 421, and applying a voltage from the alternating-current power supply 2 regardless of the on-off state of the first relay contact 411 and the second relay contact 421, a first voltage detection circuit 7 connected between the first wiring 31 on the load 10 side of the first relay contact 411 and the second wiring 32 on the load 10 side of the second relay contact 421, and applying the same voltage as the comparison voltage detection circuit 6 when the first relay contact 411 and the second relay contact 421 are in the closed state, a second voltage detection circuit 8 connected between the first wiring 31 on the alternating-current power supply 2 side of the first relay contact 411 and the second wiring 32 on the load 10 side of the second relay contact 421, and applying the same voltage as the comparison voltage detection circuit 6 when the second relay contact 421 is in the closed state, and an abnormality detection section 51 that detects the abnormality of the first relay contact 411 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7, and detects the abnormality of the second relay contact 421 by comparing the voltage applied to the comparison voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0165] According to such a configuration, regardless of the open / close state of the first relay 41, the abnormality of the first relay contact 411 can be detected with high precision in the circuit to which a voltage is applied to the first voltage detection circuit 7. Also, regardless of the open / close state of the second relay 42, the abnormality of the second relay contact 421 can be detected with high precision in the circuit to which a voltage is applied to the second voltage detection circuit 8.

[0166] Also, as described above, in the abnormality detection method, with respect to the circuit configuration in which the comparative voltage detection circuit 6, the first voltage detection circuit 7, and the second voltage detection circuit 8 are arranged, the circuit has the AC power supply 2 connected to the load 10 via the first wiring 31 and the second wiring 32, the first relay contact 411 arranged in the middle of the first wiring 31, the second relay contact 421 arranged in the middle of the second wiring 32, the comparative voltage detection circuit 6 connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the AC power supply 2 side than the second relay contact 421, a voltage applied from the AC power supply 2 regardless of the open / close state of the first relay contact 411 and the second relay contact 421, the first voltage detection circuit 7 connected between the first wiring 31 on the load 10 side than the first relay contact 411 and the second wiring 32 on the load 10 side than the second relay contact 421, a voltage applied when the first relay contact 411 and the second relay contact 421 are in the closed state being the same as that of the comparative voltage detection circuit 6, the second voltage detection circuit 8 connected between the first wiring 31 on the AC power supply 2 side than the first relay contact 411 and the second wiring 32 on the load 10 side than the second relay contact 421, a voltage applied when the second relay contact 421 is in the closed state being the same as that of the comparative voltage detection circuit 6, the abnormality of the first relay contact 411 detected by comparing the voltage applied to the comparative voltage detection circuit 6 with the voltage applied to the first voltage detection circuit 7, and the abnormality of the second relay contact 421 detected by comparing the voltage applied to the comparative voltage detection circuit 6 with the voltage applied to the second voltage detection circuit 8.

[0167] According to such a method, regardless of the open / close state of the first relay 41, the abnormality of the first relay contact 411 can be detected with high precision in the circuit to which a voltage is applied to the first voltage detection circuit 7. Also, regardless of the open / close state of the second relay 42, the abnormality of the second relay contact 421 can be detected with high precision in the circuit to which a voltage is applied to the second voltage detection circuit 8.

[0168] With the third embodiment described above, the same effects as those of the first embodiment described above can be achieved.

[0169] The abnormality detection circuit and the abnormality detection method of the present application have been described above based on the illustrated embodiments, but the present application is not limited to them, and the configurations of the respective parts can be replaced with any configurations having the same functions. In addition, any other configurations can be added to the present application.

Claims

1. An anomaly detection circuit, characterized by, has: an alternating-current power source connected to a load via a first wiring and a second wiring; a first relay contact disposed midway of the first wiring; a second relay contact disposed midway of the second wiring; a comparison voltage detection circuit that applies a voltage from the alternating-current power source regardless of the open / close state of the first relay contact and the second relay contact; a first voltage detection circuit that applies a voltage from the alternating-current power source when the first relay contact is in a closed state and applies a voltage from a first capacitor when the first relay contact is in an open state; a second voltage detection circuit that applies a voltage from the alternating-current power source when the second relay contact is in a closed state and applies a voltage from a second capacitor when the second relay contact is in an open state; and an abnormality detection unit that detects an abnormality of the first relay contact based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the first voltage detection circuit and detects an abnormality of the second relay contact based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the second voltage detection circuit. has:

2. An anomaly detection circuit, characterized by, an alternating-current power source connected to a load via a first wiring and a second wiring; a first relay contact disposed midway of the first wiring; a second relay contact disposed midway of the second wiring; a comparison voltage detection circuit connected between the first wiring on the side closer to the alternating-current power source than the first relay contact and the second wiring on the side closer to the alternating-current power source than the second relay contact, which applies a voltage from the alternating-current power source regardless of the open / close state of the first relay contact and the second relay contact; a first voltage detection circuit connected between the first wiring on the side closer to the load than the first relay contact and the second wiring on the side closer to the alternating-current power source than the second relay contact, which applies the same voltage as the comparison voltage detection circuit when the first relay contact is in a closed state and applies a voltage from a first capacitor when the first relay contact is in an open state; a second voltage detection circuit connected between the first wiring on the side closer to the alternating-current power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact, which applies the same voltage as the comparison voltage detection circuit when the second relay contact is in a closed state and applies a voltage from a second capacitor when the second relay contact is in an open state; and an abnormality detection unit that detects an abnormality of the first relay contact based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the first voltage detection circuit and detects an abnormality of the second relay contact based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the second voltage detection circuit. has:

3. An anomaly detection circuit, characterized by, an alternating-current power source connected to a load via a first wiring and a second wiring; a first relay contact disposed midway of the first wiring; ​ a second relay contact point arranged midway in the second wiring; a first comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point; a second comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point in a manner opposite to the first comparison voltage detection circuit, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point; a first voltage detection circuit connected between the first wiring on the side closer to the load than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying the same voltage as the first comparison voltage detection circuit when the first relay contact point is in the closed state, and applying a voltage from a first capacitor when the first relay contact point is in the open state; a second voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the load than the second relay contact point, and applying the same voltage as the second comparison voltage detection circuit when the second relay contact point is in the closed state, and applying a voltage from a second capacitor when the second relay contact point is in the open state; and an abnormality detection unit that detects an abnormality of the first relay contact point based on at least one of a duty cycle difference and a phase difference between the voltage applied to the first comparison voltage detection circuit and the voltage applied to the first voltage detection circuit, and detects an abnormality of the second relay contact point based on at least one of a duty cycle difference and a phase difference between the voltage applied to the second comparison voltage detection circuit and the voltage applied to the second voltage detection circuit. has:

4. An anomaly detection circuit, characterized by, an AC power source connected to a load via first wiring and second wiring; a first relay contact point arranged midway in the first wiring; a second relay contact point arranged midway in the second wiring; a comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact point and the second wiring on the side closer to the AC power source than the second relay contact point, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact point and the second relay contact point; a first voltage detection circuit connected between the first wiring on the side closer to the load than the first relay contact point and the second wiring on the side closer to the load than the second relay contact point, and applying the same voltage as the comparison voltage detection circuit when the first relay contact point and the second relay contact point are in the closed state, and applying a voltage from a first capacitor when the first relay contact point is in the open state; ​ a second voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact and applying the same voltage as the comparison voltage detection circuit when the second relay contact is in the closed state and applying a voltage from a second capacitor when the second relay contact is in the open state; an abnormality detection unit detecting an abnormality of the first relay contact based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the first voltage detection circuit and detecting an abnormality of the second relay contact based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the second voltage detection circuit.

5. An anomaly detection method characterized by, To a circuit, a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit are configured, the circuit having: an AC power source connected to a load via a first wiring and a second wiring; a first relay contact disposed in the middle of the first wiring; and a second relay contact disposed in the middle of the second wiring, the comparison voltage detection circuit applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact, the first voltage detection circuit applying a voltage from the AC power source when the first relay contact is in the closed state and applying a voltage from a first capacitor when the first relay contact is in the open state, the second voltage detection circuit applying a voltage from the AC power source when the second relay contact is in the closed state and applying a voltage from a second capacitor when the second relay contact is in the open state, an abnormality of the first relay contact is detected based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the first voltage detection circuit, an abnormality of the second relay contact is detected based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the second voltage detection circuit.

6. An anomaly detection method characterized by, To a circuit, a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit are configured, the circuit having: an AC power source connected to a load via a first wiring and a second wiring; a first relay contact disposed in the middle of the first wiring; and a second relay contact disposed in the middle of the second wiring, the comparison voltage detection circuit connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact and applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact, The first voltage detection circuit is connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact, and applies the same voltage as the comparison voltage detection circuit when the first relay contact is in the closed state, and applies a voltage from a first capacitor when the first relay contact is in the open state. The second voltage detection circuit is connected between the first wiring on the side closer to the load than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact, and applies the same voltage as the comparison voltage detection circuit when the second relay contact is in the closed state, and applies a voltage from a second capacitor when the second relay contact is in the open state. An abnormality of the first relay contact is detected based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the first voltage detection circuit. An abnormality of the second relay contact is detected based on at least one of a duty cycle difference and a phase difference between the voltage applied to the comparison voltage detection circuit and the voltage applied to the second voltage detection circuit.

7. An anomaly detection method characterized by, A circuit is configured with a first comparison voltage detection circuit, a second comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit, the circuit having: an AC power source connected to a load via a first wiring and a second wiring; a first relay contact disposed in the middle of the first wiring; and a second relay contact disposed in the middle of the second wiring, the first comparison voltage detection circuit being connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact, the second comparison voltage detection circuit being connected in reverse to the first comparison voltage detection circuit between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact, the first voltage detection circuit being connected between the first wiring on the side closer to the load than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact, and applying the same voltage as the first comparison voltage detection circuit when the first relay contact is in the closed state, and applying a voltage from a first capacitor when the first relay contact is in the open state, the second voltage detection circuit being connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact, and applying the same voltage as the second comparison voltage detection circuit when the second relay contact is in the closed state, and applying a voltage from a second capacitor when the second relay contact is in the open state. The second voltage detection circuit is connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact, and applies the same voltage as the second comparison voltage detection circuit when the second relay contact is in the closed state, and applies a voltage from a second capacitor when the second relay contact is in the open state. An abnormality of the first relay contact is detected based on at least one of a duty cycle difference and a phase difference between a voltage applied to the first comparison voltage detection circuit and a voltage applied to the first voltage detection circuit. An abnormality of the second relay contact is detected based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the second voltage detection circuit.

8. An anomaly detection method characterized by, A circuit is configured with a comparison voltage detection circuit, a first voltage detection circuit, and a second voltage detection circuit, the circuit having: an AC power source connected to a load via a first wiring and a second wiring; a first relay contact disposed in the middle of the first wiring; and a second relay contact disposed in the middle of the second wiring, the comparison voltage detection circuit being connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the AC power source than the second relay contact, and applying a voltage from the AC power source regardless of the open / close state of the first relay contact and the second relay contact, the first voltage detection circuit being connected between the first wiring on the side closer to the load than the first relay contact and the second wiring on the side closer to the load than the second relay contact, and applying the same voltage as the comparison voltage detection circuit when the first relay contact and the second relay contact are in the closed state, and applying a voltage from a first capacitor when the first relay contact is in the open state, the second voltage detection circuit being connected between the first wiring on the side closer to the AC power source than the first relay contact and the second wiring on the side closer to the load than the second relay contact, and applying the same voltage as the comparison voltage detection circuit when the second relay contact is in the closed state, and applying a voltage from a second capacitor when the second relay contact is in the open state, an abnormality of the first relay contact is detected based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the first voltage detection circuit, an abnormality of the second relay contact is detected based on at least one of a duty cycle difference and a phase difference between a voltage applied to the comparison voltage detection circuit and a voltage applied to the second voltage detection circuit.

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