JP2010146841A - Failure diagnostic device and failure diagnosis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a failure diagnostic device capable of diagnosing a failure of a transistor to drive an electromagnetic relay without changing power supply state to a load connected to the electromagnetic relay. <P>SOLUTION: The failure diagnostic device 5 includes a test signal generating part 51 which outputs to a base of a bipolar transistor 4 a test signal to make the bipolar transistor 4 non-conductive for a short time shorter than a restoration time of the electromagnetic relay 3 when the electromagnetic relay 3 is in operation, a voltage detection part 52 which diagnoses a collector voltage of the bipolar transistor 4, and a judgement part 53 which judges whether the bipolar transistor 4 is defective or not based on the collector voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic relay driven by a semiconductor switch, and more particularly to a technique for diagnosing a failure of a semiconductor switch without changing the state of a load connected to the electromagnetic relay.

  Conventionally, an electromagnetic relay (electromagnetic contactor) is used as a relay device that opens and closes a large load current flowing through a motor or the like. FIG. 8 is a diagram illustrating a configuration of a general electromagnetic relay 10. The electromagnetic relay 10 includes a coil 11, a spring 12, a movable iron core 13, a fixed contact 14 a, and a movable contact 14 b, and the coil 11 is connected to a power supply 16 through a semiconductor switch 15. A contact 14 composed of a fixed contact 14a and a movable contact 14b is a make contact that closes when the electromagnetic relay 10 operates.

  FIG. 8A shows a state in which the electromagnetic relay 10 is at rest, and the semiconductor switch 15 is in an off state. At this time, since no voltage is applied to the coil 11, no electromagnetic force is generated in the coil 11, and the coil 11 and the movable iron core 13 are separated by the spring 12, and accordingly, the fixed contact 14 a and the movable contact 14 b are separated. It is separated. That is, the contact 14 is in an open state.

  FIG. 8B shows a state where the electromagnetic relay 10 is operating, and the semiconductor switch 15 is in an ON state. At this time, a voltage is applied to the coil 11 by the power supply 16, and an electromagnetic force is generated in the coil 11. Thereby, the movable iron core 13 is attracted to the coil 11, and accordingly, the fixed contact 14a and the movable contact 14b are in contact with each other, that is, the contact 14 is closed.

  As described above, in the electromagnetic relay 10, the contact 14 is opened / closed by turning on / off the semiconductor switch 15. Therefore, when the semiconductor switch 15 is broken, the opening / closing control of the contact 14 cannot be performed. Therefore, in order to ensure the safety of the electromagnetic relay 10, it is important to diagnose and detect not only the failure of the contact 14 but also the failure of the semiconductor switch 15.

  Here, when the operation of the redundant contact on the load side connected to the electromagnetic relay 10 is monitored to diagnose the failure of the semiconductor switch 15, it cannot be determined whether the load is a failure or the failure of the semiconductor switch 15. . Therefore, it is necessary to change the operating state of the semiconductor switch 15 to check whether it is normally conducting / non-conducting.

  Patent Documents 1 and 2 are cited as documents disclosing a technique for diagnosing a failure of a semiconductor switch that controls an electromagnetic relay.

  However, Patent Document 1 cannot be applied to a system in which a change in the state of a load connected to the relay device is not allowed because the relay device must be operated when checking the function of the semiconductor switch.

On the other hand, in the configuration disclosed in Patent Document 2, when the semiconductor switch that controls the electromagnetic relay is a voltage-driven semiconductor element, the failure of the semiconductor element is detected by detecting the presence or absence of the gate current of the semiconductor element that does not flow in normal operation. Is diagnosed. In this configuration, since the operation state of the semiconductor element is not changed, the failure of the semiconductor element can be diagnosed without changing the load state even when the electromagnetic relay is connected to the load.
JP-A-3-265401 (published on November 26, 1991) JP 2003-219631 A (published July 31, 2003)

  However, the configuration of Patent Document 1 has a problem that a failure of a semiconductor element cannot be diagnosed unless the semiconductor switch is in a conductive state. Further, in the configuration of Patent Document 1, since the semiconductor switch for controlling the electromagnetic relay is limited to a voltage-driven semiconductor element such as an IGB combining a MOS transistor and a bipolar transistor, it cannot be applied to a current-driven semiconductor element. .

  The present invention has been made in view of the above problems, and its purpose is to diagnose a failure of a transistor driving an electromagnetic relay without changing the power supply state to a load connected to the electromagnetic relay. It is to implement a fault diagnosis apparatus and a fault diagnosis method.

  In order to solve the above-described problem, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil. And the sum of the turn-on time and the turn-off time of the transistor is shorter than the return time of the electromagnetic relay, and shorter than the return time of the electromagnetic relay when the transistor is on and the electromagnetic relay is operating. Transistor control means capable of outputting a control signal for turning off the transistor to the control electrode of the transistor, and whether or not the transistor is defective based on whether or not the transistor is turned off during the period. And determining means for determining.

  According to the above configuration, when the electromagnetic relay is operating, that is, when the voltage is applied to the coil while the transistor is in a conductive state, the transistor is not turned on for a period shorter than the return time of the electromagnetic relay by the transistor control means. Is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is non-conductive. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is non-conductive during the period. it can. Here, when the transistor becomes non-conductive, the coil is in a state where no voltage is applied, but since the period in which no voltage is applied to the coil is shorter than the return time of the electromagnetic relay, the electromagnetic relay is in a dormant state. The operating state continues. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In order to solve the above-described problem, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil. The sum of the turn-on time and the turn-off time of the transistor is shorter than the operation time of the electromagnetic relay, and when the transistor is non-conductive and the electromagnetic relay is at rest, the period is shorter than the operation time of the electromagnetic relay. Transistor control means capable of outputting a control signal for conducting the transistor to the control electrode of the transistor, and determination means for determining whether the transistor is defective based on whether the transistor is conducted during the period It is characterized by having.

  According to the above configuration, when the electromagnetic relay is at rest, that is, when the transistor is in a non-conducting state and no voltage is applied to the coil, the transistor control means conducts the transistor for a period shorter than the operation time of the electromagnetic relay. The control signal to be output is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is turned on. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is turned on during the period. Here, when the transistor is turned on, a voltage is applied to the coil, but the period during which the voltage is applied to the coil is shorter than the operation time of the electromagnetic relay, so the electromagnetic relay will not be in the operating state and will be in the dormant state Will continue. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In the failure diagnosis apparatus according to the present invention, the determination means may detect whether or not the transistor has operated in response to the control signal, based on the potential of at least one of the controlled electrodes of the transistor. .

  The failure diagnosis method according to the present invention is a failure diagnosis method for diagnosing a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil in order to solve the above-described problem. The sum of the turn-on time and the turn-off time of the transistor is shorter than the return time of the electromagnetic relay, and when the transistor is conductive and the electromagnetic relay is operating, the period is shorter than the return time of the electromagnetic relay. A transistor control step for outputting a control signal for turning off the transistor to the control electrode of the transistor, and determining whether the transistor is defective based on whether the transistor is turned off during the period. And a determination step.

  According to the above configuration, when the electromagnetic relay is operating, that is, when the voltage is applied to the coil while the transistor is in a conductive state, the transistor is turned off for a period shorter than the return time of the electromagnetic relay in the transistor control step. Is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is non-conductive. Therefore, in the determination step, it is determined whether the transistor is defective based on whether the transistor is non-conductive during the period. it can. Here, when the transistor becomes non-conductive, the coil is in a state where no voltage is applied, but since the period in which no voltage is applied to the coil is shorter than the return time of the electromagnetic relay, the electromagnetic relay is in a dormant state. The operating state continues. Therefore, there is an effect that it is possible to realize a failure diagnosis method capable of diagnosing a failure of a transistor that drives the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  A failure diagnosis method according to the present invention is a failure diagnosis method for diagnosing a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a state of a contact by an electromagnetic force of the coil, the turn-on time of the transistor And the turn-off time is shorter than the operation time of the electromagnetic relay, and when the transistor is non-conductive and the electromagnetic relay is at rest, a control signal for making the transistor conductive for a period shorter than the operation time of the electromagnetic relay is A transistor control step for outputting to the control electrode of the transistor and a determination step for determining whether or not the transistor is defective based on whether or not the transistor is turned on during the period are characterized.

  According to the above configuration, when the electromagnetic relay is at rest, that is, when the transistor is in a non-conductive state and no voltage is applied to the coil, the transistor is turned on for a period shorter than the operation time of the electromagnetic relay in the transistor control step. The control signal to be output is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is turned on. Therefore, in the determination step, it can be determined whether the transistor is defective based on whether the transistor is turned on during the period. Here, when the transistor is turned on, a voltage is applied to the coil, but the period during which the voltage is applied to the coil is shorter than the operation time of the electromagnetic relay, so the electromagnetic relay will not be in the operating state and will be in the dormant state Will continue. Therefore, there is an effect that it is possible to realize a failure diagnosis method capable of diagnosing a failure of a transistor that drives the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In order to solve the above problems, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that opens and closes a make contact by electromagnetic force of the coil. The transistor is turned off for a period shorter than the return time of the electromagnetic relay when the sum of the turn-on time and the turn-off time of the transistor is shorter than the return time of the electromagnetic relay and the make contact is closed. Transistor control means capable of outputting a signal to the control electrode of the transistor, and determination means for determining whether or not the transistor is defective based on whether or not the transistor is turned off during the period It is characterized by.

  According to the above configuration, when the make contact is closed, that is, when a voltage is applied to the coil while the transistor is in a conductive state, the transistor is made non-conductive for a period shorter than the return time of the electromagnetic relay by the transistor control means. A control signal is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is non-conductive. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is non-conductive during the period. it can. Here, when the transistor becomes non-conductive, the coil is in a state where no voltage is applied, but since the period when the voltage is not applied to the coil is shorter than the return time of the electromagnetic relay, the make contact is not opened. Absent. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In order to solve the above problems, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that opens and closes a make contact by electromagnetic force of the coil. When the total turn-on time and turn-off time of the transistor is shorter than the operation time of the electromagnetic relay and the make contact is open, a control signal for conducting the transistor for a period shorter than the operation time of the electromagnetic relay is Transistor control means capable of outputting to the control electrode of the transistor and determination means for determining whether or not the transistor is defective based on whether or not the transistor is conductive during the period .

  According to the above configuration, when the make contact is open, that is, when the transistor is non-conductive and no voltage is applied to the coil, the transistor control means causes the transistor to conduct for a period shorter than the electromagnetic relay operating time. A control signal is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is turned on. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is turned on during the period. Here, when the transistor is turned on, a voltage is applied to the coil. However, since the voltage is applied to the coil is shorter than the operation time of the electromagnetic relay, the make contact is not closed. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In order to solve the above-described problem, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that opens and closes a break contact by electromagnetic force of the coil. When the sum of the turn-on time and the turn-off time of the transistor is shorter than the operation time of the electromagnetic relay and the break contact is closed, a control signal for conducting the transistor for a period shorter than the operation time of the electromagnetic relay is Transistor control means capable of outputting to the control electrode of the transistor and determination means for determining whether or not the transistor is defective based on whether or not the transistor is conductive during the period .

  According to the above configuration, when the break contact is closed, that is, when the transistor is in a non-conductive state and no voltage is applied to the coil, the transistor control means causes the transistor to conduct for a period shorter than the operation time of the electromagnetic relay. A control signal is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is turned on. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is turned on during the period. Here, when the transistor is turned on, a voltage is applied to the coil. However, since the voltage is applied to the coil is shorter than the operation time of the electromagnetic relay, the break contact is not opened. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  In order to solve the above-described problem, a failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that opens and closes a break contact by electromagnetic force of the coil. And controlling the transistor to be non-conductive for a period shorter than the return time of the electromagnetic relay when the sum of the turn-on time and the turn-off time of the transistor is shorter than the return time of the electromagnetic relay and the break contact is open. Transistor control means capable of outputting a signal to the control electrode of the transistor, and determination means for determining whether or not the transistor is defective based on whether or not the transistor is turned off during the period It is characterized by.

  According to the above configuration, when the break contact is open, that is, when a voltage is applied to the coil while the transistor is in a conductive state, the transistor is turned off for a period shorter than the return time of the electromagnetic relay by the transistor control means. A control signal is output to the control electrode of the transistor. At this time, if the transistor is normal, the transistor is non-conductive. Therefore, the determination unit can determine whether the transistor is defective based on whether the transistor is non-conductive during the period. it can. Here, when the transistor becomes non-conductive, the coil is in a state where no voltage is applied, but since the period when the voltage is not applied to the coil is shorter than the return time of the electromagnetic relay, the break contact is not closed. Absent. Therefore, there is an effect that it is possible to realize a failure diagnosis device capable of diagnosing a failure of a transistor driving the electromagnetic relay without changing a power supply state to a load connected to the electromagnetic relay.

  As described above, the failure diagnosis device according to the present invention is a failure diagnosis device that diagnoses a failure of a transistor that controls a voltage applied to the coil of an electromagnetic relay that controls the state of a contact by electromagnetic force of the coil, The sum of the turn-on time and turn-off time of the transistor is shorter than the return time of the electromagnetic relay, and the transistor is turned on for a period shorter than the return time of the electromagnetic relay when the transistor is conductive and the electromagnetic relay is operating. A transistor control means capable of outputting a control signal for non-conduction to the control electrode of the transistor, and a determination for determining whether or not the transistor is defective based on whether or not the transistor is non-conductive during the period Without changing the power supply state to the load connected to the electromagnetic relay. An effect that a failure of a transistor for driving the over can be realized diagnosable fault diagnosis apparatus.

  Further, as described above, the failure diagnosis method according to the present invention is a failure diagnosis method for diagnosing a failure of a transistor that controls a voltage applied to the coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil. The sum of the turn-on time and the turn-off time of the transistor is shorter than the return time of the electromagnetic relay, and when the transistor is conductive and the electromagnetic relay is operating, the period is shorter than the return time of the electromagnetic relay. A transistor control step for outputting a control signal for turning off the transistor to the control electrode of the transistor, and determining whether the transistor is defective based on whether the transistor is turned off during the period. Changing the power supply state to the load connected to the electromagnetic relay. Ku, an effect that a failure of a transistor for driving the electromagnetic relay can be realized diagnosable failure diagnosis method.

  An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 2 is a block diagram illustrating a configuration of the control system 1 according to the present embodiment. The control system 1 includes a programmable display 2, an electromagnetic relay 3, a relay control unit 4, a failure diagnosis unit 5, and a device 6.

  The programmable display 2 is a portable HMI (Human Machine Interface) for the user to control / monitor the control system 1 and has an antenna 21. Moreover, the programmable display 2 is provided with the display screen which is not shown in figure, a touchscreen, and an emergency stop button, and transmits the instruction | indication signal according to a user's operation from the antenna 21. FIG.

  The device 6 is, for example, an electromagnetic valve or an actuator that is arranged on the production line. A device power supply V <b> 1 that supplies power to the device 6 is connected to the device 6 via the electromagnetic relay 3. The electromagnetic relay 3 is configured to open and close the contact by the electromagnetic force of the coil. When the contact of the electromagnetic relay 3 is closed, power is supplied from the device power supply V1 to the device 6 and when the contact is open, the device The power supply from the power supply V1 to the device 6 is cut off.

  A relay power source V <b> 2 that drives the electromagnetic relay 3 is connected to the electromagnetic relay 3 via the relay control unit 4. The relay control unit 4 may be a switching element such as various transistors, and a bipolar transistor is used in the present embodiment. Relay control unit 4 and relay power supply V2 correspond to semiconductor switch 15 and power supply 16 shown in FIG. An antenna 41 for receiving a signal from the antenna 21 of the programmable display device 2 is connected to the relay control unit 4.

  In a normal time, the contact of the electromagnetic relay 3 is closed, and power is supplied to the device 6. Here, when the device 6 is urgently stopped, the user presses the urgent stop button of the programmable display device 2 to transmit a stop signal from the antenna 21. The relay control unit 4 receives the stop signal from the antenna 41, and the relay control unit 4 becomes non-conductive. Thereby, the contact of the electromagnetic relay 3 is opened, and the power supply to the device 6 is interrupted.

  Further, in the control system 1, a failure diagnosis unit 5 for diagnosing a failure of the relay control unit 4 is connected to the relay control unit 4. Next, failure diagnosis of the relay control unit 4 by the failure diagnosis unit 5 will be specifically described with reference to FIG.

  FIG. 1 is a diagram showing a specific configuration of the electromagnetic relay 3, the relay control unit 4, and the failure diagnosis unit 5 shown in FIG. In this embodiment, since the relay control unit 4 is a bipolar transistor, the relay control unit 4 is referred to as a bipolar transistor 4 in the following description. In FIG. 1, the antenna 41 shown in FIG. 2 is omitted.

  The electromagnetic relay 3 includes a coil 31, a contact 32 and a diode 33. The overall configuration of the electromagnetic relay 3 is substantially the same as that of the electromagnetic relay 10 shown in FIG. That is, the configuration of the coil 31 is substantially the same as the configuration of the coil 11 shown in FIG. 8, and the configuration of the contact 32 is substantially the same as the fixed contact 14a and the movable contact 14b shown in FIG.

  The contact 32 is a make contact that is closed when the electromagnetic relay 3 is operated. Specifically, the contact 32 is closed when a voltage is applied to the coil 31, and the contact 32 is open when a voltage is not applied to the coil 31.

  The coil 31 is connected to the collector of the bipolar transistor 4, and the emitter of the bipolar transistor 4 is grounded. Thus, when the bipolar transistor 4 is conductive, the voltage from the relay power supply V2 is applied to the coil 31, and when the bipolar transistor 4 is non-conductive, no voltage is applied to the coil 31. As described above, the bipolar transistor 4 controls the voltage applied to the coil 31.

  The failure diagnosis unit 5 includes a test signal generation unit 51, a voltage detection unit 52, and a determination unit 53. The test signal generator 51 is connected to the base of the bipolar transistor 4 and outputs a test signal (control signal) for failure diagnosis of the bipolar transistor 4 to the base. Specific description regarding the test signal will be described later.

  The voltage detection unit 52 is connected to the collector of the bipolar transistor 4 and detects the collector voltage of the bipolar transistor 4. The determination unit 53 determines whether or not the bipolar transistor 4 is defective based on the test signal and the collector voltage of the bipolar transistor 4.

  The test signal generated by the test signal generating unit 51 is a signal that makes the bipolar transistor 4 non-conductive for a period shorter than the return time of the electromagnetic relay 3. First, the return time will be described.

  FIG. 3 shows a case where the contact 32 changes from the closed state (ON) to the open state (OFF). (A) to (d) are the base current of the bipolar transistor 4, the collector voltage of the bipolar transistor 4, It is a figure which shows the electric current of the coil 31, and the opening / closing state of the contact 32. FIG.

First, when the base current of the bipolar transistor 4 is I _B, since the bipolar transistor 4 is in a conducting state, the voltage applied to the coil 31 becomes V _ON a power supply V2 and the potential relay. Since the resistance of the bipolar transistor 4 is much smaller than the resistance of the coil 31, the collector voltage of the bipolar transistor 4 is 0V at this time.

Then, when at time T ₁ the base current of the bipolar transistor 4 becomes 0 from I _B, the bipolar transistor 4 is rendered non-conductive. At this time, the collector voltage of the bipolar transistor 4 is V _ON which is the same potential as the relay power supply V2, and the voltage applied to the coil 31 is zero. When the applied voltage becomes 0, the current flowing through the coil 31 circulates through a loop composed of the coil 31 and the diode 33. However, an induced electromotive force is generated in the coil 31 in a direction that cancels the change in the current. as shown in FIG. 3 (c), the current in the coil 31, immediately unlike the base current of the bipolar transistor 4 becomes 0 to I _B, gradually decreases. Accordingly, the electromagnetic force of the coil 31 also decreases gradually, the contact 32 is the time constant from the time point of T _1, to continue the closed state.

Thereafter, when the current of the coil 31 at time _{T 2} is decreased to relay interrupting current _{I OFF,} as shown in FIG. 3 (d), the contact 32 is opened (OFF). The relay cut-off current I _OFF is, for example, about 10% of the steady current I ₀ . Thus, the contact 32 is not immediately opened even when the bipolar transistor 4 is turned off. When the bipolar transistor 4 is turned off, the coil 31 is not applied with a voltage. A time T _OFF (T _OFF = T ₂ −T ₁ ) from when the voltage is not applied to the coil 31 until the contact 32 is opened is referred to as a return time (relay opening delay time). Although this return time varies depending on the model of the electromagnetic relay 3, it is approximately 4 to 40 ms.

  Next, the operation of the transistor failure diagnosis apparatus will be described.

  4A to 4D are diagrams showing the base current of the bipolar transistor 4, the collector voltage of the bipolar transistor 4, the current of the coil 31, and the open / closed state of the contact 32, respectively, at the time of the failure diagnosis test of the bipolar transistor 4. It is.

The base current of the bipolar transistor 4 shown in FIG. 4A is output from the test signal generating unit 51 and has a waveform that becomes 0 for a period t ₁ every predetermined time. Accordingly, if the bipolar transistor 4 is normal, the bipolar transistor 4 becomes non-conductive, and the voltage applied to the coil 31 becomes 0 for the period t ₁ . In the present embodiment, the period t1 is ₁ ms.

Therefore, if the bipolar transistor 4 is normal, when the base current of the bipolar transistor 4 is 0, the collector voltage waveform of the bipolar transistor 4 is V _ON as shown in FIG. The collector voltage of the bipolar transistor 4 is detected by the voltage detection unit 52 shown in FIG. 1, and the detection result is input to the determination unit 53.

Further, the output waveform of the test signal generation unit 51 is also input to the determination unit 53. Determination unit 53 by comparing the waveforms of the test signal of the collector voltage of the bipolar transistor 4, the bipolar transistor 4 detects whether it is non-conductive in the period t _1. Thereby, it can be determined whether or not the bipolar transistor 4 is defective.

Here, as described above, the period t ₁ is set to 1 ms shorter than the return time T _OFF of the electromagnetic relay 3. Therefore, even if the bipolar transistor 4 becomes non-conductive, the current of the coil 31 does not drop to the relay cutoff current I _OFF as shown in FIG. Therefore, the contact 32 remains in the closed state (ON), and the state of the device 6 connected to the electromagnetic relay 3 does not change. For example, the device 6 in the operating state remains in the operating state and the state does not change. That is, the power supply state to the load does not change.

The period t ₁ is set within a time range during which the bipolar transistor 4 can operate. In general, since the operation speed of the semiconductor switch is faster than the operation speed of the electromagnetic relay, the operable time of the bipolar transistor 4 is shorter than the return time of the electromagnetic relay 3. Therefore, it is easy to make the bipolar transistor 4 nonconductive only for a period shorter than the return time of the electromagnetic relay 3.

  Further, in the present embodiment, the cycle in which the bipolar transistor 4 is turned off by the test signal is set to 100 ms, for example. This period is appropriately set according to the safety standard required for the electromagnetic relay 3.

  As described above, in the present embodiment, during the failure diagnosis test of the bipolar transistor 4, the bipolar transistor 4 is turned off for a period shorter than the return time of the electromagnetic relay 3, so that the contact 32 remains closed. Therefore, it is possible to diagnose whether or not the bipolar transistor 4 has failed by operating the bipolar transistor 4 without changing the state of the device 6.

In the above embodiment, when the base current changes from 0 to I _B, but is determined by whether the collector voltage is V _ON from 0, stepwise the base current, that is, until 0 I _B For example, if the collector voltage is changed in 10 steps and the change in the collector voltage is measured, aging and deterioration of the bipolar transistor 4 can be diagnosed. For example, when it is observed that a base current higher than a predetermined level is required compared to the time when new use is started in order to set the collector voltage to V _ON , it is determined that the bipolar transistor 4 has deteriorated. In this case, the time required for the base current to change to 0 to I _B, is a matter of course should be shorter than the recovery time. Thereby, since the presence or absence of deterioration of the bipolar transistor 4 can be diagnosed, the malfunction of the electromagnetic relay 3 due to the failure of the bipolar transistor 4 can be prevented in advance. Even when a MOS transistor is used instead of the bipolar transistor 4, the deterioration of the MOS transistor may be diagnosed by changing the gate voltage stepwise.

Due to deterioration, the collector voltage may occasionally be V _ON due to a base current lower than a predetermined value, but in any case, the collector voltage becomes V _ON due to a base current different from the predetermined base current. Therefore, deterioration can be diagnosed.

  The configuration for diagnosing the presence or absence of a failure of the bipolar transistor 4 with the contact 32 of the electromagnetic relay 3 closed has been described above. Next, a configuration for diagnosing the presence or absence of a failure of the bipolar transistor 4 with the contact 32 of the electromagnetic relay 3 opened will be described. In this case, the test signal generation unit 51 shown in FIG. 1 outputs a test signal for making the bipolar transistor 4 conductive for a period shorter than the operation time of the electromagnetic relay 3. First, the operation time will be described.

  FIG. 5 shows a case where the contact 32 shown in FIG. 1 changes from an open state (OFF) to a closed state (ON). (A) to (d) are the base current of the bipolar transistor 4 and the bipolar transistor 4 respectively. It is a figure which shows the collector voltage of this, the electric current of the coil 31, and the switching state of the contact 32. FIG.

First, when the base current of the bipolar transistor 4 is 0, since the bipolar transistor 4 is in a non-conducting state, the voltage applied to the coil 31 is 0. At this time, the collector voltage of the bipolar transistor 4 becomes V _ON which is the same potential as the relay power supply V2.

Subsequently, when the base current of the bipolar transistor 4 changes from 0 to I _B at time T _3, the bipolar transistor 4 becomes conductive. At this time, the potential of the collector of the bipolar transistor 4 immediately becomes zero. Therefore, although the voltage applied to the coil 31 is V _ON , an induced electromotive force is generated that works in a direction that cancels the change in the current. Therefore, as shown in FIG. 0 Unlike the base current of the bipolar transistor 4 becomes I _B, gradually increases. Accordingly, the electromagnetic force of the coil 31 also increases gradually, the contact 32 is the time constant from the time of T _3, to continue the open state.

Thereafter, when the current of the coil 31 at time _{T 4} increases to relay driving current _{I ON,} as shown in FIG. 5 (d), the contact 32 is closed (ON). Relay driving current _{I ON} is, for example, about 75% of the steady-state current _{I 0.} Thus, even if the bipolar transistor 4 becomes conductive, the contact 32 is not immediately closed. When the bipolar transistor 4 becomes conductive, the coil 31 is applied. The time T _ON (T _ON = T ₄ −T ₃ ) from when the voltage is applied to the coil 31 until the contact 32 is closed is referred to as the operation time (relay closing delay time). Although this operation time varies depending on the model of the electromagnetic relay 3, it is approximately 8 to 50 ms.

  6A to 6D are diagrams showing the base current of the bipolar transistor 4, the collector voltage of the bipolar transistor 4, the current of the coil 31, and the open / closed state of the contact 32 at the time of the failure diagnosis test of the bipolar transistor 4. It is.

The base current of the bipolar transistor 4 shown in FIG. 6 (a) is output from the test signal generation unit 51, and a waveform comprising only I _B period t ₂ at predetermined time intervals. Accordingly, if normal bipolar transistor 4, the bipolar transistor 4 becomes conductive, the voltage applied to only the coil 31 period t ₂ is V _ON. In the present embodiment, it has a duration _{t 2} and 1 ms.

Thus, if the bipolar transistor 4 is normal, the base current of the bipolar transistor 4 when I _B, as shown in FIG. 6 (b), the value of the collector voltage of the bipolar transistor 4 becomes zero. The collector voltage of the bipolar transistor 4 is detected by the voltage detection unit 52 shown in FIG. 1, and the detection result is input to the determination unit 53. The determination unit 53 calculates the waveform of the collector voltage of the bipolar transistor 4 and the waveform of the test signal. by comparison, the bipolar transistor 4 detects whether the conduction period t _2. Thereby, it is possible to diagnose whether or not the bipolar transistor 4 is defective.

Here, as described above, the period _{t 2} is set to be shorter than the operating time _{T ON} of the electromagnetic relay 3 1 ms. Therefore, even when the bipolar transistor 4 is conductive, as shown in FIG. 6 (c), the current of the coil 31 is not be raised to the relay driving current I _ON. Accordingly, the contact 32 remains in the open state (OFF), and the state of the device 6 connected to the electromagnetic relay 3 does not change.

The period t ₂ of the above are also similar to the period t _1, the bipolar transistor 4 is set within the range of operable time. In general, since the operation speed of the semiconductor switch is faster than the operation speed of the electromagnetic relay, the operable time of the bipolar transistor 4, that is, the sum of the turn-on time and the turn-off time of the semiconductor switch is larger than the operation time of the electromagnetic relay 3. Also short. Therefore, it is easy to make the bipolar transistor 4 conductive for a period shorter than the operation time of the electromagnetic relay 3.

  As described above, in the present embodiment, during the failure diagnosis test of the bipolar transistor 4, the bipolar transistor 4 is turned on for a period shorter than the operation time of the electromagnetic relay 3, so that the contact 32 remains open. Therefore, it is possible to diagnose whether or not the bipolar transistor 4 has failed without changing the state of the device 6.

  In the present embodiment, the voltage detection unit 52 is configured to detect the collector voltage of the bipolar transistor 4, but is not limited thereto, and for example, as shown in FIG. 7, the voltage detection unit 52 includes the bipolar transistor 4. The emitter voltage may be detected. In this case, it is necessary to provide a resistor 7 between the emitter of the bipolar transistor 4 and the ground so that the emitter voltage differs between when the bipolar transistor 4 is in a conductive state and when it is in a non-conductive state.

  In the present embodiment, the determination unit 53 determines whether or not the bipolar transistor 4 is turned on / off according to the test signal based on the collector voltage or the emitter voltage of the bipolar transistor 4 detected by the voltage detection unit 52. Although it has been detected, the method of detecting whether or not the bipolar transistor 4 is turned on / off according to the test signal is not limited to this. For example, the determination unit 53 may detect whether or not the bipolar transistor 4 is turned on / off according to the test signal by detecting a current flowing through the collector or emitter of the bipolar transistor 4.

  In the present embodiment, the case where the contact 32 is a make contact that is closed when the electromagnetic relay 3 is operated is described. However, the present invention is not limited to this, and the contact 32 is open when the electromagnetic relay 3 is operated. It may be a break contact. In this case, the bipolar transistor 4 is controlled as follows at the time of a fault diagnosis test of the bipolar transistor 4.

  That is, when the contact 32 is closed, the bipolar transistor 4 is turned on for a period shorter than the operation time of the electromagnetic relay 3. Thereby, since the contact 32 is maintained in the closed state, it is possible to diagnose the presence or absence of the failure of the bipolar transistor 4 without changing the state of the device 6. On the other hand, when the contact 32 is open, the bipolar transistor 4 is turned off for a period shorter than the return time of the electromagnetic relay 3. Thereby, since the contact 32 is maintained in the open state, the presence / absence of the failure of the bipolar transistor 4 can be diagnosed without changing the state of the device 6.

  Further, the contact 32 may be a switching contact. In this case, when the bipolar transistor 4 is turned on and the electromagnetic relay 3 is in an operating state, the bipolar transistor 4 is turned off for a period shorter than the return time of the electromagnetic relay 3. Further, when the bipolar transistor 4 is non-conductive and the electromagnetic relay 3 is in a dormant state, the bipolar transistor 4 is made conductive for a period shorter than the operation time of the electromagnetic relay 3. Thereby, since the state of the contact 32 does not change during the failure diagnosis test, it is possible to diagnose the presence or absence of the failure of the bipolar transistor 4 without changing the state of the device 6.

  In the present embodiment, the bipolar transistor 4 is an NPN type bipolar transistor, but a PNP type bipolar transistor may be used as the bipolar transistor 4. A MOS transistor may be used as a semiconductor switch for driving the coil 31 of the electromagnetic relay 3.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be suitably applied to a control system including an electromagnetic relay driven by a semiconductor switch.

It is a figure which shows the specific structure of the electromagnetic relay of the control system which concerns on embodiment of this invention, a relay control part, and a failure diagnostic part. It is a block diagram which shows the structure of the control system which concerns on embodiment of this invention. 1 shows a case where the contact shown in FIG. 1 is changed from a closed state to an open state, wherein (a) to (d) are the base current of the bipolar transistor and the collector voltage of the bipolar transistor of the control system according to the embodiment of the present invention, respectively. It is a figure which shows the electric current of a coil, and the switching state of a contact. (A)-(d) is a figure which shows the base current of a bipolar transistor, the collector voltage of a bipolar transistor, the current of a coil, and the open / close state of a contact, respectively, at the time of a fault diagnosis test of a bipolar transistor. FIG. 1 shows a case where the contact shown in FIG. 1 is changed from an open state to a closed state, and (a) to (d) show the base current of the bipolar transistor, the collector voltage of the bipolar transistor, the current of the coil, and the switching state of the contact, respectively. FIG. (A)-(d) is a figure which shows the base current of a bipolar transistor, the collector voltage of a bipolar transistor, the current of a coil, and the open / close state of a contact, respectively, at the time of a fault diagnosis test of a bipolar transistor. It is a circuit diagram which shows the structure of the relay control part which concerns on the modification of embodiment of this invention. It is a figure which shows the structure of a general electromagnetic relay.

Explanation of symbols

3 Electromagnetic relay 4 Bipolar transistor (transistor)
5. Failure diagnosis unit (failure diagnosis device)
31 Coil 32 Contact 51 Test signal generator (transistor control means)
52 Voltage detector (determination means)
53 determination unit (determination means)

Claims (5)

A failure diagnosis device for diagnosing a failure of a transistor that controls a voltage applied to the coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil,
The sum of the turn-on time and turn-off time of the transistor is shorter than the return time of the electromagnetic relay,
Transistor control means capable of outputting to the control electrode of the transistor a control signal for making the transistor non-conductive for a period shorter than a return time of the electromagnetic relay when the transistor is conducting and the electromagnetic relay is operating;
A failure diagnosis apparatus comprising: determination means for determining whether or not the transistor is defective based on whether or not the transistor is turned off during the period. A failure diagnosis device for diagnosing a failure of a transistor that controls a voltage applied to the coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil,
The sum of the turn-on time and turn-off time of the transistor is shorter than the operation time of the electromagnetic relay,
A transistor control means capable of outputting a control signal for conducting the transistor to a control electrode of the transistor for a period shorter than an operation time of the electromagnetic relay when the transistor is non-conductive and the electromagnetic relay is inactive;
A failure diagnosis apparatus comprising: a determination unit that determines whether or not the transistor is defective based on whether or not the transistor is turned on during the period.   3. The determination unit according to claim 1, wherein the determination unit detects whether or not the transistor is operated in accordance with the control signal based on a potential of at least one of the controlled electrodes of the transistor. Fault diagnosis device. A failure diagnosis method for diagnosing a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil,
The sum of the turn-on time and turn-off time of the transistor is shorter than the return time of the electromagnetic relay,
A transistor control step for outputting, to the control electrode of the transistor, a control signal for turning off the transistor for a period shorter than a return time of the electromagnetic relay when the transistor is conducting and the electromagnetic relay is operating;
And a determination step of determining whether or not the transistor is defective based on whether or not the transistor is turned off during the period. A failure diagnosis method for diagnosing a failure of a transistor that controls a voltage applied to a coil of an electromagnetic relay that controls a contact state by an electromagnetic force of the coil,
The sum of the turn-on time and turn-off time of the transistor is shorter than the operation time of the electromagnetic relay,
A transistor control step for outputting a control signal for conducting the transistor to a control electrode of the transistor for a period shorter than an operation time of the electromagnetic relay when the transistor is non-conductive and the electromagnetic relay is inactive;
And a determination step of determining whether or not the transistor is defective based on whether or not the transistor is turned on during the period.

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