JP2018195128A - Diagnostic system - Google Patents

Abstract

To provide a diagnostic device that detects a malfunction of an emergency stop circuit.SOLUTION: A diagnostic device 100 comprises: one or more cut-off circuit 2 that cuts off supply of power to a to-be-protected block 1; a cut-off diagnostic device 3 that makes a diagnostic determination whether the cut-off circuit 2 is in an abnormal state or not; and a voltage detection circuit 3 that detects voltage supplied to the to-be-protected block 1. The cut-off diagnostic device 3 outputs a cut-off signal to the cut-off circuit 2. When a cut-off signal is output from the cut-off diagnostic device 3, the cut-off circuit 2 cuts off supply of power to the to-be-protected block 1. The cut-off diagnostic device 3 makes a diagnosis on the basis of voltage supplied to the to-be-protected block 1, which is detected by a voltage detection circuit 4 in a case where a cut-off signal is output. When a diagnostic determination is made that the cut-off circuit 2 is in an abnormal state, an abnormality signal indicating that the cut-off circuit 2 is in an abnormal state is output to the outside.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a diagnostic apparatus for diagnosing the presence or absence of a circuit abnormality.

  In a system in which a motor is controlled by PWM (Pulse Width Modulation) control, digital control using a microprocessor is widely performed. In order to control the motor, it is necessary to detect the current flowing in the motor winding (hereinafter referred to as the motor current). In the digital control, the motor current is detected at every PWM cycle for generating the PWM switching timing. Control is performed using PI control (proportional + integral control) or the like so as to coincide with the command value. Since the torque output by the synchronous motor (Surface Permanent Magnet Synchronous Motor) used in FA servo is proportional to the motor current, the motor current value is controlled by PWM control and output from the motor. Torque can be controlled freely.

  On the other hand, as a method for stopping the motor in an emergency, a technique for reducing the failure risk of the emergency stop circuit has been proposed (see, for example, Patent Document 1). Such a conventional emergency stop circuit is configured such that the motor can be stopped even if one of the emergency stop circuits fails by duplicating the emergency stop circuit system as shown in FIG. Yes.

JP 2006-268130 A

  However, the configuration of the conventional emergency stop circuit cannot detect that the emergency stop circuit has failed.

  The diagnostic device according to the present invention includes at least one cutoff circuit that cuts off power supply to the protection target block, a cutoff diagnostic device that diagnoses whether there is an abnormality in the cutoff circuit, and a supply voltage to the protection target block. A voltage detection circuit for detecting, the interruption diagnostic device outputs a interruption signal to the interruption circuit, and the interruption circuit outputs the interruption signal to the protection target block when the interruption diagnostic device outputs the interruption signal. The power supply is cut off, and the cut-off diagnostic device performs the diagnosis based on the supply voltage to the protection target block detected by the voltage detection circuit when the cut-off signal is output, and When a diagnosis that there is an abnormality is made, an abnormality signal indicating that the interruption circuit is abnormal is output to the outside.

  The diagnostic device according to the present invention includes an inverter circuit that controls a ratio of a main power supply voltage applied to a motor by PWM (Pulse Width Modulation) control, a drive circuit that drives the inverter circuit, and an emergency stop command from the outside. A shut-off circuit for shutting off power supply to the drive circuit, a shut-off diagnostic device for diagnosing whether or not the shut-off circuit is abnormal, and a diagnostic pulse generator for outputting a shut-off signal to the shut-off circuit, Further, when the cutoff signal is output from the diagnostic pulse generator, the power supply to the drive circuit is cut off. When the cutoff signal is output from the diagnostic pulse generator, In this case, the diagnosis is performed by detecting the supply voltage to the drive circuit, and if the diagnosis is made that there is an abnormality in the shut-off circuit, there is an abnormality in the shut-off circuit outside. An abnormal signal indicating that the signal is output is output.

  According to the diagnostic apparatus, it is possible to detect that the interruption circuit that is an emergency stop circuit has failed.

1 is a block configuration diagram of a diagnostic device according to Embodiment 1. FIG. 3 is an operation waveform diagram of the diagnostic apparatus according to Embodiment 1. FIG. 6 is a block configuration diagram of a diagnostic apparatus according to Embodiment 2. FIG. 6 is a block configuration diagram of a diagnostic apparatus according to Embodiment 3. FIG. FIG. 6 is a block configuration diagram of a diagnostic device according to Embodiment 4. FIG. 10 is a block configuration diagram of a diagnostic apparatus according to a fifth embodiment. FIG. 10 is a block configuration diagram of a diagnostic apparatus according to a sixth embodiment. It is a block block diagram of the interruption | blocking circuit of a prior art example.

  A diagnostic device according to an aspect of the present disclosure includes one or more cutoff circuits that cut off power supply to a protection target block, a cutoff diagnostic device that diagnoses whether there is an abnormality in the cutoff circuit, and the protection block A voltage detection circuit for detecting a supply voltage, the interruption diagnostic device outputs a cutoff signal to the cutoff circuit, and the cutoff circuit outputs the cutoff signal when the cutoff signal is output from the cutoff diagnostic device. The power supply to the block is cut off, and the cut-off diagnostic device performs the diagnosis based on the supply voltage to the protection target block detected by the voltage detection circuit when the cut-off signal is output, When a diagnosis is made that there is an abnormality in the cutoff circuit, an abnormality signal indicating that there is an abnormality in the cutoff circuit is output to the outside.

  According to the diagnostic apparatus, it is possible to detect that the interruption circuit that is an emergency stop circuit has failed.

  Further, when the shutoff diagnostic device outputs the shutoff signal, the supply voltage to the protection target block detected by the voltage detection circuit is within a predetermined period from the time when the shutoff signal is output. If the voltage is not lower than the lower limit voltage, the abnormality is diagnosed, and the predetermined voltage may be higher than a lower limit voltage at which the protection target block operates normally.

  As a result, it is possible to diagnose an abnormality of the cutoff circuit that stops energization of the protection target block even in a state where the protection target block is operating.

  The shut-off circuit includes a plurality of shut-off circuits, and the shut-off diagnostic device outputs the shut-off signals to the shut-off circuits at different timings, and performs the diagnosis on the shut-off circuits at different timings. You may do it.

  As a result, even if any one of the interrupting circuits breaks down, the reliability can be further improved by interrupting the energization with the normally operating interrupting circuit.

  A diagnostic device according to an aspect of the present disclosure includes an inverter circuit that controls a ratio of a main power supply voltage applied to a motor by PWM (Pulse Width Modulation) control, a drive circuit that drives the inverter circuit, and an emergency stop from the outside In response to a command, a cutoff circuit that cuts off power supply to the drive circuit, a cutoff diagnostic device that diagnoses whether there is an abnormality in the cutoff circuit, and a diagnostic pulse generator that outputs a cutoff signal to the cutoff circuit, The cutoff circuit further cuts off the power supply to the drive circuit when the diagnostic signal is output from the diagnostic pulse generator, and the cutoff diagnostic device outputs the cutoff signal from the diagnostic pulse generator In this case, the diagnosis is performed by detecting the supply voltage to the drive circuit, and when the diagnosis is made that there is an abnormality in the cutoff circuit, the cutoff circuit is connected to the outside. An abnormality signal indicating that there is an abnormality is output.

  According to the diagnostic apparatus, it is possible to detect that the interruption circuit that is an emergency stop circuit has failed.

  In addition, when the cutoff signal is output from the diagnostic pulse generator, the cutoff diagnostic device is configured so that the supply voltage to the drive circuit to be detected is within a predetermined period from the time when the cutoff signal is output. If the voltage is not lower than the voltage, a diagnosis that there is an abnormality is made, and the predetermined voltage may be higher than a lower limit voltage at which the motor operates normally.

  As a result, it is possible to diagnose an abnormality of the cutoff circuit that stops energization of the drive circuit even when the motor is being driven.

  The inverter circuit includes a P-side power element and an N-side power element, and the drive circuit controls a P-side drive circuit that controls an ON state and an OFF state of the P-side power element, and the N-side power element. An N-side drive circuit that controls an ON state and an OFF state of the power supply circuit, and the cutoff circuit cuts off the power supply to the P-side drive circuit when the cutoff signal is output from the diagnostic pulse generator A first cutoff circuit; and a second cutoff circuit that shuts off power supply to the N-side drive circuit when the cutoff signal is output from the diagnostic pulse generator, wherein the diagnostic pulse generator The cut-off signal is output to the first cut-off circuit and the second cut-off circuit, and the cut-off diagnostic device outputs the P-side drive when the cut-off signal is output from the diagnostic pulse generator to the first cut-off circuit. Supply voltage to the circuit And out, in a case where the interruption signal from the diagnostic pulse generator to the second cutoff circuit is output, by performing the detection of the supply voltage to the N-side drive circuit may be carried out the diagnosis.

  Thus, by alternately diagnosing the P-side drive circuit and the N-side drive circuit, it is possible to diagnose an abnormality of the cutoff circuit that stops energization of the drive circuit even when the motor is being driven.

  In addition, a signal obtained by logically synthesizing the emergency stop command and the cutoff signal is input to the cutoff circuit, and the cutoff circuit generates a signal from the diagnostic pulse generator when the emergency stop command becomes active. The power supply to the drive circuit may be cut off when a cut-off signal is output.

  Thereby, energization to the drive circuit can be stopped when an emergency stop command is input from the outside.

  The emergency stop command may be interrupted by the interrupt signal.

  Thereby, diagnosis including the input circuit to which the emergency stop command is input can be performed.

  The PWM generator further generates a PWM pulse for driving the inverter circuit by a PWM method, and the PWM generator supplies power to at least one of the P-side drive circuit and the N-side drive circuit. The generation of the PWM pulse may be stopped when the operation is not performed.

  Thereby, reliability can be improved more.

  Furthermore, a PWM generator that generates a PWM pulse for driving the inverter circuit by a PWM method may be provided, and the PWM generator may stop generating the PWM pulse when the emergency stop command becomes active.

  Thereby, reliability can be improved more.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. The invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

(Embodiment 1)
A diagnostic apparatus 100 according to the first embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a block configuration diagram of the diagnostic apparatus 100 according to the first embodiment, and FIG. 2 is an operation waveform diagram of the diagnostic apparatus 100.

  As shown in FIG. 1, the diagnostic device 100 includes a cutoff circuit 2, a cutoff diagnostic device 3, and a voltage detection circuit 4.

  In the figure, a protection target block 1 is a circuit block to be protected from an energization abnormality. For example, the protection target block 1 is configured by a low voltage system, and is a block that needs to be protected against application of a high voltage from the outside.

  The shutoff circuit 2 shuts off power supply to the protection target block 1 when a shutoff signal (described later) is output from the shutoff diagnostic device 3.

  The voltage detection circuit 4 detects the supply voltage to the protection target block 1.

  The interruption diagnosing device 3 outputs an interruption signal to the interruption circuit 2 and, based on the supply voltage to the protection target block 1 detected by the voltage detection circuit 4 when the interruption signal is output, the abnormality of the interruption circuit 2 is detected. When the presence / absence is diagnosed and the interruption circuit 2 is diagnosed as having an abnormality, an abnormality signal indicating that the interruption circuit 2 has an abnormality is output to the outside.

  The above is the description of each block. Next, the diagnosis method of the cutoff circuit 2 will be described with reference to FIG.

  Diagnosis of the presence or absence of an abnormality in the shut-off circuit 2 starts when the shut-off diagnostic device 3 outputs a shut-off signal. The cutoff circuit 2 cuts off the power supply during the active period of the cutoff signal (the cutoff signal is L period in FIG. 2). When the shutoff diagnostic device 3 detects that the output voltage from the shutoff circuit 2 (that is, the supply voltage to the protection target block 1) is lowered to a predetermined determination voltage level in conjunction with the shutoff signal, Inactive (diagnostic pulse is H period in FIG. 2). The interruption circuit 2 supplies power when the interruption signal returns to inactive, thereby ending the diagnosis of whether the interruption circuit 2 is abnormal.

  The determination voltage level can be configured so as not to affect the operation of the protection target block by setting a voltage higher than the lower limit voltage at which the protection target block 1 operates normally. The above is the description of the normal operation of the diagnostic apparatus.

  Next, an operation when the interruption circuit 2 has an abnormality will be described. If the output voltage of the cutoff circuit 2 does not drop to the determination voltage level within the predetermined determination time during the active period of the cutoff signal of the cutoff diagnostic device 3, the cutoff diagnostic device 3 operates normally. It is determined that it is not, and an abnormal signal is output to the outside.

  That is, the shutoff diagnostic device 3 outputs the shutoff signal when the supply voltage to the protection target block 1 detected by the voltage detection circuit 4 is less than the predetermined voltage within a predetermined period from the time when the shutoff signal is output. If not lowered, it is determined that there is an abnormality.

  With the configuration as described above, it is possible to diagnose whether or not there is an abnormality in the cutoff circuit 2 that stops energization of the protection target block 1 even when the protection target block 1 is in operation.

  The period for generating the cutoff signal may be diagnosed within the MTFB (mean failure time) of the cutoff circuit 2, but may be diagnosed at one minute intervals or the like in order to further improve the reliability.

(Embodiment 2)
A diagnostic apparatus 100a according to the second embodiment will be described with reference to FIG. The difference from the diagnostic device 100 according to the first embodiment is that a plurality of cutoff circuits 2 exist on the power supply line to the protection target block 1, which will be described below.

  Although FIG. 3 shows an example in which two blocking circuits 2 are provided for one protection target block 1, a plurality of three or more configurations may be used. The interruption diagnosing device 3 is configured to output diagnostic pulses with a time difference to the respective interruption circuits 2 and sequentially diagnose the interruption circuits.

  That is, the interruption diagnosing device 3 outputs an interruption signal to each of the interruption circuits 2a and 2b at different timings, and performs diagnosis for each of the interruption circuits 2a and 2b at different timings.

  For example, when the diagnosis result of the cutoff circuit 2a is abnormal, in addition to outputting an abnormal signal as in the above-described first embodiment, the cutoff circuit to the cutoff circuit 2b is activated to activate the cutoff circuit. The voltage output of 2b can be stopped and the protection target block 1 can be protected.

  By configuring as described above, it is possible to configure a diagnostic device with higher reliability by interrupting energization with the interrupting circuit 2 that is operating normally even if any one of the interrupting circuits 2 fails. Can do.

(Embodiment 3)
The diagnostic device 15 according to the third embodiment will be described with reference to FIGS. 4 and 2.

  FIG. 4 is a block configuration diagram of the diagnostic device 15 according to the third embodiment, and FIG. 2 is an operation waveform diagram of the diagnostic device 15.

  As shown in FIG. 4, the diagnostic device 15 includes an inverter circuit 8, a drive circuit 11, a cutoff circuit 22, a cutoff diagnostic device 3a, a synthesis circuit 12a, a synthesis circuit 12b, an input circuit 13a, and an input. The circuit 13b and the diagnostic pulse generator 14 are included.

  In the figure, a motor 9 is, for example, an induction motor that rotates by applying a three-phase sine wave, a three-phase brushless motor in which a magnet is disposed on a rotor, or the like.

  The inverter circuit 8 controls the ratio of the main power supply voltage applied to the motor 9 by PWM (Pulse Width Modulation) control. More specifically, the inverter circuit 8 is, for example, a three-phase inverter circuit having six power elements, and a P-side power element 10a connected to the positive side (P side) of the main power supply voltage; And an N-side power element 10b connected to the negative side (N side) of the main power supply voltage.

  The drive circuit 11 drives the inverter circuit 8. More specifically, the drive circuit 11 includes a P-side drive circuit 11a that controls the on-state and off-state of the P-side power element 10a, and an N-side drive that controls the on-state and off-state of the N-side power element 10b. Circuit 11b.

  The P-side drive circuit 11a transmits a PWM signal from a PWM generator (not shown) to the P-side power element 10a. It also has a function to insulate the high-voltage primary circuit such as the inverter circuit 8 from the low-voltage secondary circuit such as a control signal or an external connection element. An element is used.

  The N-side drive circuit 11b transmits a PWM signal from a PWM generator (not shown) to the N-side power element 10b. In addition, as with the P-side drive circuit 11a, there is also a function of insulating a high-voltage primary circuit such as the inverter circuit 8 from a low-voltage secondary circuit such as a control signal or an external connection element. An insulating element such as an optocoupler is used.

  The cutoff circuit 22 cuts off the power supply to the drive circuit 11 by an emergency stop signal (emergency stop command) from the outside, and further, when a cutoff signal is output from the diagnostic pulse generator 14, Shut off the power supply. More specifically, the cutoff circuit 22 is cut off from the diagnostic pulse generator 14 and the first cutoff circuit 22a that cuts off the power supply to the P-side drive circuit 11a when a cutoff signal is output from the diagnostic pulse generator 14. A second cutoff circuit 22b is configured to cut off the power supply to the N-side drive circuit 11b when a signal is output.

  When the power supply to the P-side drive circuit 11a is cut off, the power supply to the P-side power element 10a is also cut off. When the power supply to the N-side drive circuit 11b is cut off, the power supply to the N-side power element 10b is cut off. The power supply is also cut off.

  The diagnostic pulse generator 14 outputs a cutoff signal to the cutoff circuit 22. More specifically, the diagnostic pulse generator 14 periodically outputs a cutoff signal as shown in FIG. 2 in order to confirm that the cutoff circuit 22 operates correctly. The period for outputting the cutoff signal may be diagnosed within the MTFB (mean failure time) of the cutoff circuit 22, but may be diagnosed at one minute intervals or the like in order to further improve the reliability.

  The interruption diagnosing device 3 a detects the abnormality of the interruption circuit 22 by detecting the supply voltage to the drive circuit 11 when the interruption signal is output from the diagnostic pulse generator 14, and When the diagnosis that there is an abnormality is made, an abnormality signal indicating that the interruption circuit 22 has an abnormality is output to the outside. More specifically, when the interruption signal is output from the diagnostic pulse generator 14, the interruption diagnostic device 3 a detects that the supply voltage to the drive circuit 11 to be detected is within a predetermined period from when the interruption signal is output. If the voltage is not lower than the predetermined voltage, a diagnosis that there is an abnormality is made. The main difference from the interruption diagnostic device 3 according to the first embodiment is that the diagnostic pulse generator 14 is separated.

  Further, the diagnostic pulse generator 14 may be configured to diagnose the presence or absence of an abnormality in the cutoff circuit 22 based on the information of the operating power supply from the cutoff diagnostic device 3a.

  The input circuit 13a and the input circuit 13b are input circuits for an emergency stop signal (emergency stop command), and are configured by a redundant circuit using a plurality of signals and circuits in order to increase reliability. Although FIG. 4 shows an example in which the input circuit has two systems, a plurality of configurations of three or more systems may be used. The emergency stop signal to the plurality of input circuits gives an emergency stop signal to each input circuit simultaneously when the motor 9 is stopped.

  The synthesizing circuit 12a and the synthesizing circuit 12b are logic synthesizing circuits, which logically synthesize the emergency stop signal from the input circuit 13a and the input circuit 13b and the cutoff signal from the diagnostic pulse generator 14 and output them to each cutoff circuit. The circuit configuration of the synthesis logic in the synthesis circuits 12a and 12b is determined by the logic of the emergency stop signal. For example, when the emergency stop is H, the cutoff circuit 22 is shut off with H, and when the emergency stop is L, the logical product As described above, the cutoff circuit can be configured to shut off the cutoff circuit 22 in response to an emergency stop signal from the outside by blocking at L.

  That is, the cutoff circuit 22 cuts off the power supply to the drive circuit 11 when the emergency stop signal (emergency stop command) becomes active and when the cutoff signal is output from the diagnostic pulse generator 14.

  Next, a diagnosis method for the cutoff circuit 22 will be described with reference to FIG.

  The diagnostic pulse generator 14 periodically outputs a cutoff signal as described above. For example, when the diagnostic pulse generator 14 outputs a cutoff signal L to the synthesis circuit 12a, the cutoff diagnostic device 3a detects that the operating power output from the first cutoff circuit 22a has dropped to the determination voltage level, and the diagnostic pulse The diagnostic result is output to the generator 14. The diagnosis is completed when the diagnostic pulse generator 14 returns the diagnostic pulse to H.

  Based on this result, the diagnostic pulse generator 14 confirms that the cutoff circuit is operating normally, and then performs the same operation on the synthesis circuit 12b. In this series of operations, when the diagnostic pulse generator 14 outputs a cutoff signal to the synthesis circuit 12a, the operating voltage from the first cutoff circuit 22a detected by the cutoff diagnostic device 3a is the first cutoff during the active period of the cutoff signal. If the output voltage of the circuit 22a (that is, the supply voltage to the P-side drive circuit 11a) does not drop to the determination voltage level within a predetermined determination time, the interruption diagnostic device 3a is abnormal in the first interruption circuit 22a. It is judged that there is, and an abnormal signal is output outside. Then, the diagnostic pulse generator 14 outputs a cutoff signal to the synthesis circuit 12b to stop energization of the motor 9.

  Even when the operating voltage output from the first cutoff circuit 22a or the second cutoff circuit 22b is lower than the determination voltage level with respect to the combining circuit 12a or 12b that has not output the cutoff signal, the cutoff diagnostic device 3a You may determine with the abnormality of the 1st cutoff circuit 22a or the 2nd cutoff circuit 22b.

  When the diagnostic pulse generator 14 determines that the first cutoff circuit 22a or the second cutoff circuit 22b is abnormal, the PWM generator (not shown) generates a PWM signal to be output to the P-side drive circuit 11a and / or the N-side drive circuit 11b. Generation may be stopped. In the same case, the cutoff circuit 22 outputs a stop signal to the synthesis circuit 12a and / or the synthesis circuit 12b so as to stop the supply of the operating power to the P-side drive circuit 11a and / or the N-side drive circuit 11b. May be.

  With the configuration as described above, it is possible to diagnose whether or not there is an abnormality in the cutoff circuit 22 that stops energization of the motor 9 even when the motor 9 is being driven.

(Embodiment 4)
The diagnostic device 15a according to the fourth embodiment will be described with reference to FIG. What is different from the diagnostic device 15 according to the third embodiment is a method of inputting a diagnostic pulse signal, which will be described below.

  As shown in FIG. 5, the cutoff signal from the diagnostic pulse generator 14 in the fourth embodiment is configured to cut off the emergency stop signal from the outside. Signals from the input circuit 13a and the input circuit 13b are directly connected to the first cutoff circuit 22a and the second cutoff circuit 22b, respectively. That is, the diagnostic device 15a is configured by deleting the synthesis circuit 12a and the synthesis circuit 12b from the diagnostic device 15.

  The operation of diagnostic pulse generator 14 is the same as that of the third embodiment.

  The diagnostic pulse generator 14 outputs a cut-off signal so as to cut off the emergency stop signal connected to the input circuit 13a to cut off the operating power from the first cut-off circuit 22a, and the cut-off diagnostic device 3a By detecting the voltage, it is determined whether there is an abnormality in the first cutoff circuit 22a.

  Similarly, the diagnostic pulse generator 14 outputs a cutoff signal so as to cut off the emergency stop signal connected to the input circuit 13b to cut off the operating power from the second cutoff circuit 22b, and the cutoff diagnostic device 3a By detecting the voltage of the operating power supply, it is determined whether the second cutoff circuit 22b is abnormal.

  When the diagnostic pulse generator 14 determines that the first cutoff circuit 22a or the second cutoff circuit 22b is abnormal, the PWM generator (not shown) generates a PWM signal to be output to the P-side drive circuit 11a and / or the N-side drive circuit 11b. Generation may be stopped. In the same case, the cutoff circuit 22 may stop supplying the operating power to the P-side drive circuit 11a and / or the N-side drive circuit 11b.

  With the above-described configuration, in addition to diagnosing an abnormality in the cutoff circuit that stops energization of the motor 9 even when the motor 9 is being driven, the cutoff circuit 22 including the input circuits 13a and 13b. It becomes possible to perform diagnosis.

(Embodiment 5)
The diagnostic device 15b according to the fifth embodiment will be described with reference to FIG. What is different from the diagnostic device 15 according to the third embodiment is a method of stopping the motor 9 when an emergency stop signal is input and when the interruption diagnostic device 3a determines that there is an abnormality, which will be described below.

  The PWM generator 16 generates a PWM pulse for driving the inverter circuit 8 by the PWM method.

  When the motor 9 is a three-phase motor, the PWM pulse is supplied to the P-side drive circuit 11a and the N-side drive circuit 11b to drive the P-side power element 10a and the N-side power element 10b as shown in FIG. In contrast, a total of six PWM signals are output.

  Here, when the interruption diagnostic device 3a diagnoses the interruption circuit 22 as abnormal, the diagnostic pulse generator 14 outputs a interruption signal to each of the synthesis circuits 12a and 12b and outputs a diagnostic abnormality signal to the PWM generator 16 to generate PWM. The device 16 stops the PWM output and stops energization of the motor 9.

  With the above-described configuration, in addition to diagnosing the presence or absence of an abnormality in the cutoff circuit 22 that stops energization of the motor 9 even when the motor 9 is being driven, the PWM output signal is also stopped in the event of an abnormality. Therefore, it is possible to configure a more reliable diagnostic device.

(Embodiment 6)
A diagnostic device 15c according to the sixth embodiment will be described with reference to FIG. What is different from the diagnostic device 15 according to the third embodiment is a method in which the diagnostic device 15a according to the fourth embodiment and the diagnostic device 15b according to the fifth embodiment are combined, which will be described below.

  The diagnostic pulse generator 14 according to the sixth embodiment outputs a diagnostic abnormality signal to the PWM generator 16 in addition to the same operation as that of the diagnostic device 15a according to the fourth embodiment. The operation of the PWM generator 16 in the sixth embodiment is the same as that in the fifth embodiment.

  With the above-described configuration, in addition to diagnosing an abnormality in the cutoff circuit that stops energization of the motor 9 even when the motor 9 is being driven, the cutoff circuit 22 including the input circuits 13a and 13b. Since the PWM output signal is also stopped at the time of diagnosis and when an abnormality occurs, a more reliable diagnostic device can be configured.

  The present invention can be widely used in a diagnostic apparatus for diagnosing the presence or absence of a circuit abnormality.

DESCRIPTION OF SYMBOLS 1 Block to be protected 2, 2a, 2b, 22 Cutoff circuit 3, 3a Cutoff diagnostic device 4 Voltage detection circuit 8 Inverter circuit 9 Motor 10a P side power element 10b N side power element 11 Drive circuit 11a P side drive circuit 11b N side drive Circuit 12a, 12b Combining circuit 13a, 13b Input circuit 14 Diagnostic pulse generator 15, 15a, 15b, 15c, 100, 100a Diagnostic device 16 PWM generator 22a First cutoff circuit 22b Second cutoff circuit

Claims (10)

One or more shut-off circuits for shutting off power supply to the block to be protected;
An interruption diagnostic device for diagnosing the presence or absence of an abnormality in the interruption circuit;
A voltage detection circuit for detecting a supply voltage to the protection target block,
The interruption diagnostic device outputs a interruption signal to the interruption circuit,
When the cutoff signal is output from the cutoff diagnostic device, the cutoff circuit cuts off the power supply to the protection target block,
The interruption diagnosis device performs the diagnosis based on the supply voltage to the protection target block detected by the voltage detection circuit when the interruption signal is output, and diagnoses that the interruption circuit is abnormal. When performed, an abnormality signal indicating that there is an abnormality in the cutoff circuit is output to the outside. When the shut-off diagnostic device outputs the shut-off signal, the supply voltage to the protection target block detected by the voltage detection circuit is less than a predetermined voltage within a predetermined period from the output of the shut-off signal. If not, make a diagnosis of the abnormality,
The diagnostic apparatus according to claim 1, wherein the predetermined voltage is a voltage higher than a lower limit voltage at which the protection target block operates normally. The interruption circuit is plural,
The said interruption | blocking diagnostic device outputs the said interruption | blocking signal with a mutually different timing with respect to each of the said interruption | blocking circuits, and performs the said diagnosis about each of the said interruption | blocking circuits at a mutually different timing. Or the diagnostic apparatus of 2. An inverter circuit that controls the ratio of the main power supply voltage applied to the motor by PWM (Pulse Width Modulation) control;
A drive circuit for driving the inverter circuit;
A shut-off circuit that shuts off power supply to the drive circuit in response to an emergency stop command from the outside;
An interruption diagnostic device for diagnosing the presence or absence of an abnormality in the interruption circuit;
A diagnostic pulse generator for outputting a cutoff signal to the cutoff circuit;
The cutoff circuit further cuts off power supply to the drive circuit when the cutoff signal is output from the diagnostic pulse generator,
The interruption diagnostic device performs the diagnosis by detecting a supply voltage to the drive circuit when the interruption signal is output from the diagnostic pulse generator, and diagnoses that the interruption circuit is abnormal. When performed, an abnormality signal indicating that there is an abnormality in the cutoff circuit is output to the outside. When the cutoff signal is output from the diagnostic pulse generator, the cutoff diagnostic device detects that the supply voltage to the drive circuit to be detected is less than a predetermined voltage within a predetermined period from when the cutoff signal is output. If it does not go down, diagnose that there is an abnormality,
The diagnostic apparatus according to claim 4, wherein the predetermined voltage is higher than a lower limit voltage at which the motor operates normally. The inverter circuit includes a P-side power element and an N-side power element,
The drive circuit includes a P-side drive circuit that controls an ON state and an OFF state of the P-side power element, and an N-side drive circuit that controls an ON state and an OFF state of the N-side power element,
When the cutoff signal is output from the diagnostic pulse generator, the cutoff circuit outputs a first cutoff circuit that cuts off power supply to the P-side drive circuit, and the cutoff signal is output from the diagnostic pulse generator. A second cutoff circuit that cuts off the power supply to the N-side drive circuit,
The diagnostic pulse generator outputs the cutoff signal to the first cutoff circuit and the second cutoff circuit,
The cutoff diagnostic device detects a supply voltage to the P-side drive circuit when the cutoff signal is output from the diagnostic pulse generator to the first cutoff circuit, and detects the supply voltage from the diagnostic pulse generator to the second cutoff circuit. The diagnostic apparatus according to claim 4 or 5, wherein the diagnosis is performed by detecting a supply voltage to the N-side drive circuit when the cutoff signal is output to the cutoff circuit. A signal obtained by logically combining the emergency stop command and the cutoff signal is input to the cutoff circuit.
The cutoff circuit cuts off the power supply to the drive circuit when the emergency stop command becomes active and when the cutoff signal is output from the diagnostic pulse generator. Item 7. The diagnostic device according to any one of Items 4 to 6. The diagnostic device according to any one of claims 4 to 6, wherein the emergency stop command is interrupted by the interrupt signal. Furthermore, a PWM generator for generating a PWM pulse for driving the inverter circuit by a PWM method,
The PWM generator stops generation of the PWM pulse when power is not supplied to at least one of the P-side drive circuit and the N-side drive circuit. The diagnostic device according to any one of the above. Furthermore, a PWM generator for generating a PWM pulse for driving the inverter circuit by a PWM method,
The diagnostic device according to any one of claims 4 to 8, wherein the PWM generator stops generating a PWM pulse when the emergency stop command becomes active.

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