JP6391402B2 - DCDC converter fault diagnosis device and fault diagnosis method - Google Patents

Description

  The present invention relates to a failure diagnosis apparatus and failure diagnosis method for a DCDC converter that detects a failure of a DCDC converter that outputs a boosted or lowered DC input power supply, and more particularly to a failure of a multiphase DCDC converter having a plurality of converter units. The present invention relates to a DCDC converter failure diagnosis device and a failure diagnosis method to be detected.

  2. Description of the Related Art Conventionally, a DCDC converter that converts a voltage of a DC power supply according to a load voltage is known. A multi-phase DCDC converter including a plurality of converter units that perform voltage conversion is also known. For example, Patent Document 1 is configured to change the number of converter units to be driven according to the size of a load. .

  In a multi-phase DCDC converter including a plurality of converter units, for example, in the case of a low load, even when one converter unit fails, it can be covered with the remaining converter unit and supply power of a desired voltage to the load. It is difficult to detect a failure in the converter. Therefore, in Patent Document 1, each converter unit is provided with a current detection circuit so that a failure of an individual converter unit can be detected.

JP 2012-050207 A

  However, in Patent Document 1, it is necessary to provide each converter unit with a current detection circuit for detecting current, and this is used to detect a failure of each converter unit. As described above, when a current detection circuit is provided in each converter unit, the number of parts (resistance of the current detection circuit, amplifier, etc.) increases, resulting in a problem of high cost.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a DCDC converter fault diagnosis device and a fault diagnosis method capable of detecting a fault at a low cost by reducing the number of parts.

A first aspect of the DCDC converter fault diagnosis apparatus of the present invention includes two or more converter units each having a switching unit and connected in parallel, and control for controlling the switching unit to operate at a predetermined switching cycle. A DCDC converter failure diagnosis device that detects a failure of a DCDC converter comprising: a voltage detection unit that detects a voltage of each of the switching units of the two or more converter units; and an input to the voltage detection unit A monitoring unit that monitors whether the voltage satisfies a predetermined voltage fluctuation condition, and a diagnosis unit that determines that the corresponding switching unit and the converter unit are faulty when it is determined that the voltage does not satisfy the voltage fluctuation condition. The voltage detection unit is configured to switch the switching unit during the step-up or step-down operation of the DCDC converter. The diagnostic unit detects the differential voltage between the gate / drain and the gate / source, and the diagnostic unit inputs the voltage detection unit during the step-up operation or step-down operation of the DCDC converter as the voltage fluctuation condition monitoring. Whether the differential voltage is lower than a predetermined threshold is monitored, and if the differential voltage is determined to be equal to or higher than the threshold, the corresponding switching unit and converter unit are determined to be faulty .
According to a second aspect of the DCDC converter fault diagnosis apparatus of the present invention, two or more converter units each having a switching unit and connected in parallel, and control for controlling the switching unit to operate at a predetermined switching cycle. A DCDC converter failure diagnosis device that detects a failure of a DCDC converter comprising: a voltage detection unit that detects a voltage of each of the switching units of the two or more converter units; and an input to the voltage detection unit A monitoring unit that monitors whether the voltage satisfies a predetermined voltage fluctuation condition, and a diagnosis unit that determines that the corresponding switching unit and the converter unit are faulty when it is determined that the voltage does not satisfy the voltage fluctuation condition. The control unit can be controlled by individually changing the switching period for each converter unit, A frequency change requesting unit that requests the control unit to lengthen the switching cycle of the converter unit to be monitored for the voltage fluctuation condition at the disconnection unit, and the diagnosis unit includes the two or more converter units. One by one is selected one by one, and the switching cycle of the selected converter unit is increased by a predetermined period by the frequency change request unit to detect a failure of the DCDC converter.

According to another aspect of the DCDC converter failure diagnosis apparatus of the present invention, in the second aspect of the DCDC converter failure diagnosis apparatus of the present invention described above, the diagnosis unit is performing a step-up operation of the DCDC converter to monitor the voltage fluctuation condition Alternatively, it is monitored whether the voltage input from the voltage detection unit fluctuates in synchronization with the switching cycle during a step-down operation, and a time during which the voltage does not fluctuate in synchronization with the switching cycle is determined as a predetermined failure When it is determined that the time has been reached, the corresponding switching unit and converter unit are determined to be faulty.

  In another aspect of the DCDC converter failure diagnosis apparatus of the present invention, the failure determination time is set to be equal to or longer than the switching cycle.

  In another aspect of the DCDC converter failure diagnosis apparatus of the present invention, the voltage fluctuation uses one of an edge detection method, a polling method, and a signal detection method including phase compensation for detecting synchronization with a switching period. It is detected.

According to another aspect of the DCDC converter failure diagnosis apparatus of the present invention, in the first aspect of the DCDC converter failure diagnosis apparatus of the present invention described above, the control unit individually changes the switching cycle for each converter unit. A frequency change request unit that is controllable and requests the control unit to lengthen the switching cycle of the converter unit to be monitored by the diagnostic unit, the diagnostic unit, One or more converter units are sequentially selected one by one, and the switching cycle of the selected converter unit is increased by a predetermined period by the frequency change request unit, and the failure detection of the DCDC converter is performed.

The first aspect of the DCDC converter failure diagnosis method of the present invention includes two or more converter units each having a switching unit and connected in parallel, and control for controlling the switching unit to operate at a predetermined switching cycle. A DCDC converter failure diagnosis method for detecting a failure of a DCDC converter comprising: a voltage detection step for detecting a voltage of each of the switching units of the two or more converter units; and a voltage detection step detected by the voltage detection step. A diagnosis step of monitoring whether or not a predetermined voltage fluctuation condition is input by inputting the voltage and determining that the voltage does not satisfy the voltage fluctuation condition, and determining that the corresponding switching unit and the converter unit are faulty; , have a, in the voltage detecting step, wherein the DCDC converter is also in the step-up operation The differential voltage between the gate / drain or the gate / source of the switching unit is detected during the step-down operation, and in the diagnosis step, the DCDC converter is monitored during the step-up operation or the step-down operation as a monitoring of the voltage fluctuation condition. It is monitored whether the differential voltage detected in the voltage detection step is lower than a predetermined threshold, and when the differential voltage is determined to be equal to or higher than the threshold, the corresponding switching unit and converter unit are determined to be faulty. It is characterized by.
A second aspect of the DCDC converter fault diagnosis method of the present invention includes two or more converter units each having a switching unit and connected in parallel, and control for controlling the switching unit to operate at a predetermined switching cycle. A DCDC converter failure diagnosis method for detecting a failure of a DCDC converter comprising: a voltage detection step for detecting a voltage of each of the switching units of the two or more converter units; and a voltage detection step detected by the voltage detection step. A diagnosis step of monitoring whether or not a predetermined voltage fluctuation condition is input by inputting the voltage and determining that the voltage does not satisfy the voltage fluctuation condition, and determining that the corresponding switching unit and the converter unit are faulty; The control unit individually changes the switching period for each converter unit. In the diagnosis step, the control unit is selected one by one from the two or more converter units one by one, and the control unit is requested to lengthen the switching cycle of the selected converter units by a certain period. The failure detection of the DCDC converter is performed later.

Another aspect of the DCDC converter failure diagnosis method of the present invention is the above-described second aspect of the DCDC converter failure diagnosis method of the present invention. Or monitoring whether the voltage detected in the voltage detection step fluctuates in synchronization with the switching cycle during the step-down operation, and determines whether a time during which the voltage does not fluctuate in synchronization with the switching cycle is a predetermined failure When it is determined that the time has been reached, the corresponding switching unit and converter unit are determined to be faulty.

  Another aspect of the DCDC converter failure diagnosis method of the present invention is characterized in that the failure determination time is set to be equal to or longer than the switching cycle.

  According to another aspect of the DCDC converter failure diagnosis method of the present invention, the voltage fluctuation uses one of an edge detection method, a polling method, and a signal detection method including phase compensation for detecting synchronization with a switching period. It is detected.

According to another aspect of the DCDC converter failure diagnosis method of the present invention, in the first aspect of the DCDC converter failure diagnosis method of the present invention described above, the control unit individually changes the switching cycle for each converter unit. In the diagnosis step, after selecting one by one from the two or more converter units one by one and requesting the control unit to lengthen the switching period of the selected converter units by a certain period, It is characterized by detecting a failure of the DCDC converter.

  According to the present invention, it is possible to provide a DCDC converter failure diagnosis device and a failure diagnosis method capable of detecting a failure at a low cost by reducing the number of components.

It is a block diagram which shows the structure of the DCDC converter carrying the DCDC converter fault diagnostic apparatus and DCDC converter fault diagnostic apparatus of 1st Embodiment of this invention. FIG. 6 is a timing chart showing an example of (a) a boost operation signal, (b) a control signal, (c) a drain voltage or a source voltage, and (d) an example of a diagnosis result for explaining the DCDC converter failure diagnosis method of the first embodiment. is there. It is a flowchart for demonstrating the flow of a process of the DCDC converter fault diagnostic method of 1st Embodiment. It is a block diagram which shows an example which mounted the DCDC converter fault diagnostic apparatus of 1st Embodiment in the pressure | voltage fall type multi-phase type DCDC converter. It is a block diagram which shows an example which mounted the DCDC converter fault diagnostic apparatus of 1st Embodiment in the step-up / step-down type | mold multi-phase type DCDC converter. It is a block diagram which shows the structure of the DCDC converter carrying the DCDC converter fault diagnostic apparatus and DCDC converter fault diagnostic apparatus of 2nd Embodiment of this invention. It is a block diagram which shows the structure of the DCDC converter which mounts the DCDC converter fault diagnostic apparatus and DCDC converter fault diagnostic apparatus of 3rd Embodiment of this invention. It is a flowchart for demonstrating the flow of a process of the DCDC converter fault diagnostic method of 3rd Embodiment.

  A DCDC converter failure diagnosis apparatus and failure diagnosis method according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description. The DCDC converter failure diagnosis apparatus and failure diagnosis method of the present invention are applied to a multiphase DCDC converter having a plurality of converter units.

  When the failure diagnosis of the multi-phase DCDC converter is performed using current as in Patent Document 1, a current detection circuit is required and the number of components increases. Therefore, in the DCDC converter failure diagnosis apparatus and failure diagnosis method of the present invention, the failure diagnosis is performed by detecting the voltage of the multi-phase DCDC converter.

  If the voltage (output voltage) at the output end of the multiphase DCDC converter is used as the voltage used for failure diagnosis, it may not be detected even if one converter unit fails. In particular, in the case of a light load with a small amount of power to be supplied, the remaining converter unit other than the failed converter unit may be able to cover the necessary power, and in this case, a desired voltage is maintained. As a result, even if the output voltage is monitored, it becomes difficult to detect a failure of the converter unit. Therefore, in the present invention, the failure diagnosis apparatus is configured to monitor the voltages of the plurality of converter units.

(First embodiment)
A DCDC converter failure diagnosis apparatus according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a DCDC converter failure diagnosis apparatus 100 according to the present embodiment and a multiphase DCDC converter 10 in which the DCDC converter failure diagnosis apparatus 100 is mounted. A multi-phase DCDC converter 10 shown in FIG. 1 is a step-up DCDC converter, and includes two converter units 11 as an example (referred to as 11a and 11b, respectively).

  Each converter unit 11 a, 11 b includes a field effect transistor (FET) 12, a coil 13, and a diode 14. In the multiphase DCDC converter 10 shown in FIG. 1, the FET 12 is used as a switching unit. However, the present invention is not limited to this, and a switching element such as a bipolar transistor may be used.

  In the multi-phase DCDC converter 10, two converter units 11 a and 11 b are connected in parallel and connected to the input end 15 and the output end 16. The battery 1 is connected to the input end 15, and a load (not shown) is connected to the output end 16. Capacitors 17a and 17b are connected to the input end 15 side and the output end 16 side, respectively. In the multiphase DCDC converter 10, the capacitors 17 a and 17 b are provided outside the converter unit 11, but capacitors may be provided inside each of the converter units 11 instead.

  In the multi-phase DCDC converter 10, the FET 12 provided in each of the converter units 11a and 11b is turned on / off at a predetermined switching cycle, thereby supplying power of a voltage necessary for the load. In order to perform on / off control of each FET 12, the multiphase DCDC converter 10 is provided with a control unit 18, and a predetermined control signal is output from the control unit 18 to the gate of each FET 12.

  The DCDC converter failure diagnosis apparatus 100 according to the present embodiment includes a voltage detection unit 110 and a diagnosis unit 120 in order to detect a failure of the converter unit 11. The voltage detection unit 110 detects the drain voltage or source voltage of each FET 12 and outputs the detected drain voltage or source voltage to the diagnosis unit 120. The diagnosis unit 120 diagnoses the drain voltage or the source voltage of each FET 12 to detect the failure of the FET 12 and the converter unit 11 having the failure FET 12. The processing of the diagnosis unit 120 may be performed using the same arithmetic processing circuit as that of the control unit 18.

  Since the multi-phase DCDC converter 10 includes a plurality (two in this case) of the converter units 11, even if, for example, the failure of the converter unit 11 is detected by detecting the voltage of the output end 16, the failed converter unit The converter unit 11 other than 11 may be able to supply power with a desired voltage. In that case, it becomes difficult to detect a failure of the converter unit 11. Moreover, even if the voltage of the output terminal 16 is detected and a failure of the converter unit 11 is found, it cannot be specified which converter unit among the plurality of converter units has failed.

  Therefore, in the DCDC converter failure diagnosis apparatus 100 of the present embodiment, the voltage detection unit 110 detects the drain voltage or source voltage of each FET 12. The diagnosis unit 120 inputs the drain voltage or the source voltage of each FET 12 from the voltage detection unit 110 and individually diagnoses each so that the converter unit 11 in which the FET 12 has failed can be identified.

  The diagnosis unit 120 performs the following processing to detect a failure of the converter unit 11. First, a drain voltage or a source voltage for each FET 12 is input from the voltage detection unit 110 and a boost operation signal for determining whether or not the multi-phase DCDC converter 10 is performing a boost operation is input from the control unit 18. If the diagnosis unit 120 determines that the boosting operation is being performed based on the boosting operation signal input from the control unit 18, whether the drain voltage or the source voltage varies in synchronization with the switching period in which the control unit 18 controls each FET 12. Determine whether or not.

  If the diagnosis unit 120 determines that the drain voltage or the source voltage does not change in synchronization with the switching period as a result of the determination of the voltage fluctuation, the diagnosis unit 120 obtains a continuation time in which the state that does not change in synchronization continues. When it is determined that the duration has reached a predetermined time (hereinafter referred to as failure determination time) or more, the FET 12 and the converter unit 11 having the FET 12 are determined to be failed.

  A method for diagnosing the failure of the converter unit 11 by the diagnosis unit 120 will be described in more detail with reference to FIG. FIG. 2 is a timing chart for explaining a failure diagnosis method in the diagnosis unit 120. FIG. 4A shows an example of a time change of a boosting operation signal that is turned off when the multiphase DCDC converter 10 is not performing a boosting operation and turned on during the boosting operation. FIG. 2B shows an example of the time change of the control signal output from the control unit 18 to the gate of each FET 12. FIG. 6C shows an example of the time change of the drain voltage or source voltage for each FET 12 input from the voltage detection unit 110 by the diagnosis unit 120. Further, FIG. 4D shows an example of a diagnosis result by the diagnosis unit 120.

  When the step-up operation signal shown in FIG. 2A is turned from OFF to ON, a control signal that repeats ON / OFF in a predetermined switching cycle (indicated by Ts) as shown in FIG. Is output to the gate. Thereby, the switching operation of each FET 12 is started, and the drain voltage or the source voltage repeats step-up and step-down in the switching cycle Ts. Here, when the FET 12 fails, as shown in FIG. 2C, the drain voltage or the source voltage does not repeat the step-up / step-down. FIG. 2C shows that the drain voltage or source voltage does not repeat the step-up / step-down after the time T.

  As a method for detecting the fluctuation of the drain voltage or the source voltage, the edge detection for detecting the rising / falling of the voltage, the polling for continuously monitoring the voltage high / low, and the phase shift from the control signal to the voltage fluctuation. Any one or more detection methods of phase-compensated synchronization detection that detects the synchronization between the switching period of the control signal and the voltage fluctuation after compensation can be used.

  The diagnosis unit 120 obtains an elapsed time from the time T when the drain voltage or the source voltage no longer repeats the step-up / step-down, and determines that the elapsed time has reached the failure determination time (indicated by Tc), the FET 12 and the It is determined that the converter unit 11 having the FET 12 has failed (FIG. 2D). The failure determination time Tc is preferably equal to or longer than the switching cycle Ts.

  When the diagnosis unit 120 detects a failure of any of the converter units 11, the diagnosis unit 120 forcibly stops the boosting operation by the multiphase DCDC converter 10, for example. In addition, the DCDC converter failure diagnosis apparatus 100 is configured to include a notification unit 130, and when the diagnosis unit 120 detects a failure of any one of the FETs 12, information about the failed FET 12 and the converter unit 11 having the FET 12 is notified. It is good to make it report to an external user etc. by outputting to the part 130. FIG.

  In the above description, in order to determine whether or not the multiphase DCDC converter 10 is performing a boosting operation, the boosting operation signal is input from the control unit 18 and used. On the other hand, it is also possible to input the control signal shown in FIG. 2B instead of the boosting operation signal from the control unit 18 and determine whether or not the boosting operation is being performed using the control signal. That is, while the control signal is repeatedly turned on / off at a predetermined switching cycle, it can be determined that the multiphase DCDC converter 10 is performing a boosting operation.

  A processing flow of the DCDC converter failure diagnosis method of the present embodiment will be described below with reference to FIG. FIG. 3 is a flowchart for explaining the processing flow of the DCDC converter failure diagnosis method of the present embodiment. The processing of the failure diagnosis method of the present embodiment in the DCDC converter failure diagnosis apparatus 100 is repeatedly performed at a predetermined monitoring cycle. First, in step S1, the diagnosis unit 120 inputs a step-up operation signal from the control unit 18, and determines whether or not the multi-phase DCDC converter 10 is performing a step-up operation. As a result of the determination, if it is determined that the boosting operation is being performed, the process proceeds to the next step S2.

  The following steps S2 to S7 are sequentially performed for each FET 12 of the plurality of converter units 11. In the multi-phase DCDC converter 10 shown in FIG. 1, the processes of steps S2 to S7 are sequentially performed on the FETs 12 of the two converter units 11a and 11b. In step S <b> 2, the diagnosis unit 120 inputs a drain voltage or a source voltage from the voltage detection unit 110 and performs a process for detecting the voltage fluctuation. In step S3, it is determined whether or not a voltage variation is detected. As a result of the determination, if a voltage fluctuation is detected, the process proceeds to step S4. If no voltage fluctuation is detected, the process proceeds to step S5.

  In step S4, 0 is set to the non-detection time Td as a process when a voltage fluctuation is detected. The non-detection time Td is used to calculate the time during which voltage fluctuation is not continuously detected for each FET 12 during the boost operation (the boost operation signal is on). When the process of step S4 is finished, the process of the monitoring cycle is finished. On the other hand, in step S5, as a process when voltage fluctuation is not detected, ΔT of the monitoring period is added to the non-detection time Td, and the addition result is set as the non-detection time Td again (update of the non-detection time Td).

  When the undetected time Td is updated in step S5, it is determined in the next step S6 whether or not the undetected time Td is equal to or greater than the failure determination time Tc. If it is determined in step S6 that the non-detection time Td is equal to or greater than the failure determination time Tc, the step-up operation by the multiphase DCDC converter 10 is forcibly stopped in step S7. Further, the information about the failed FET 12 and the converter unit 11 having the FET 12 is transmitted to the reporting unit 130 to notify the user or the like. On the other hand, if it is determined that the non-detection time Td is less than the failure determination time Tc, the process of the monitoring cycle is ended.

  As described above, in the DCDC converter failure diagnosis apparatus 100 and the failure diagnosis method of the present embodiment, the voltage detection unit 110 detects the drain voltage or the source voltage of each FET 12 and uses each voltage detected by the diagnosis unit 120. Thus, the failure of each FET 12 is diagnosed, so that it is not necessary to add components such as a resistor and an amplifier as in the case of using a current detection circuit, and the failure diagnosis of the multiphase DCDC converter can be performed at a low cost.

  In FIG. 1, an example in which the DCDC converter failure diagnosis apparatus 100 of the present embodiment is mounted on the step-up multiphase DCDC converter 10 is shown, but the DCDC converter failure diagnosis apparatus 100 of the present embodiment is not limited to this, The present invention can also be applied to other types of multi-phase DCDC converters. As an example, FIG. 4 shows a step-down multiphase DCDC converter 20 equipped with the DCDC converter failure diagnosis device 100 of this embodiment, and FIG. The devices equipped with the device 100 are shown in FIG.

  When the DCDC converter failure diagnosis apparatus 100 of this embodiment is mounted on the step-down multiphase DCDC converter 20 shown in FIG. 4, voltage detection is performed in the same manner as when the DCDC converter failure diagnosis apparatus 100 of the present embodiment is mounted. The unit 110 detects the drain voltage or the source voltage of the FET 12 provided in each converter unit 21 (21a, 21b), and the diagnosis unit 120 inputs the drain voltage or the source voltage detected by the voltage detection unit 110 to input each FET 12 Can be diagnosed.

  Further, in the step-up / step-down type multi-phase DCDC converter 30 shown in FIG. 5, each of the converter units 31 (31a, 31b) is provided with two FETs 12, but the DCDC converter failure diagnosis device 100 of this embodiment is mounted. When it does, the voltage detection part 110 detects the drain voltage or source voltage of both of two FET12 provided in each converter part 31. FIG. The diagnosis unit 120 performs failure diagnosis using the drain voltage or source voltage of all the FETs 12 detected by the voltage detection unit 110. Thereby, even if any of the FETs 12 fails, the failed FET 12 and the converter unit 31 having the FET 12 can be detected. Here, in the multi-phase DCDC converter 30 shown in FIG. 5, the drain voltage or the source voltage of each FET 12 is detected, but it is preferable to detect the voltage at least at the last stage of each converter unit 31a, 31b. By detecting the voltage at the last stage of each converter unit 31a, 31b, it is possible to know which converter unit has a problem. In addition, it is more preferable to detect the voltage of the drain voltage or source voltage of other FETs because the failed part can be specified in detail.

(Second Embodiment)
A DCDC converter failure diagnosis apparatus and failure diagnosis method according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of the DCDC converter failure diagnosis apparatus 200 of the present embodiment. Here, an example in which the DCDC converter failure diagnosis apparatus 200 of the present embodiment is mounted on the step-up multiphase DCDC converter 10 is shown.

  In the DCDC converter failure diagnosis apparatus 200 of the present embodiment, the voltage detection unit 210 measures the differential voltage between the gates / drains of each FET 12 or between the gates / sources. During the step-up operation of the multiphase DCDC converter 10, the voltage detection unit 210 measures the differential voltage and outputs it to the diagnosis unit 220.

  In the DCDC converter failure diagnosis method according to the present embodiment, the diagnosis unit 220 inputs a differential voltage measurement value from the voltage detection unit 210 and compares it with a predetermined threshold value. As a result, when it is determined that the differential voltage is equal to or greater than a predetermined threshold, it is determined that the FET 12 and the converter unit 11 having the FET 12 have failed. As in the first embodiment, the step-up operation by the multi-phase DCDC converter 10 is forcibly stopped, and information on the failed FET 12 and the converter unit 11 having the FET 12 is transmitted to the notification unit 130 to be transmitted to the user. It is good to report to etc.

  Even in the DCDC converter failure diagnosis apparatus 200 and the failure diagnosis method of the present embodiment, it is not necessary to add components such as a resistor and an amplifier in order to measure the differential voltage in the voltage detection unit 210, and the multiphase DCDC converter can be manufactured at low cost. Fault diagnosis can be performed.

(Third embodiment)
A DCDC converter failure diagnosis apparatus and failure diagnosis method according to a third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram illustrating a configuration of the DCDC converter failure diagnosis apparatus 300 according to the present embodiment. Also here, an example is shown in which the DCDC converter failure diagnosis apparatus 300 of the present embodiment is mounted on the step-up multiphase DCDC converter 10. The DCDC converter failure diagnosis apparatus 300 according to the present embodiment further includes a frequency change request unit 340 in addition to the DCDC converter failure diagnosis apparatus 100 according to the first embodiment.

  When the switching periods of the FETs 12 provided in the two converter units 11 are short (the switching frequency is high) and are repeatedly turned on and off at high speed, the voltage fluctuation of the drain voltage or the source voltage measured by the voltage detection unit 110 is detected. Becomes difficult. Therefore, in the DCDC converter failure diagnosis apparatus 300 according to the present embodiment, the target converter units 11 are sequentially selected one by one from the plurality of converter units 11, and the switching frequency is set to the FET 12 of the selected target converter unit 11 for a certain period. Just lower.

  The multi-phase DCDC converter to which the DCDC converter failure diagnosis apparatus 300 of this embodiment is applied includes a control unit that can individually change the switching cycle of each converter unit. The multi-phase DCDC converter can maintain the boosted output voltage even if the switching frequency is reduced by only one of the plurality of converter units.

  In this embodiment, when the target converter unit 11 is sequentially selected, control is performed from the frequency change request unit 340 so that the switching frequency of the FET 12 of the selected target converter unit 11 is lowered to a predetermined frequency lower than that. A frequency reduction request signal is output to the unit 18 for a certain period. As a result, the switching frequency of the target FET 12 decreases for a certain period. The certain period needs to be longer than at least the failure determination time Tc.

  The diagnosis unit 320 inputs the drain voltage or the source voltage of the FET 12 in the target converter unit 11 from the voltage detection unit 110 within a certain period in which the switching frequency is lowered, and determines whether or not voltage fluctuation is detected. . Then, when the FET 12 is detected as a result of the determination, the voltage variation is not detected, and the time when the voltage variation is not detected exceeds the failure determination time, the FET 12 and the converter unit 11 having the FET 12 (the selected converter unit) 11) determines that there is a failure.

  A processing flow of the DCDC converter failure diagnosis method of the present embodiment will be described below with reference to FIG. FIG. 8 is a flowchart for explaining the flow of the DCDC converter failure diagnosis method of the present embodiment processed in the DCDC converter failure diagnosis device 300. If it is determined in step S <b> 1 that the multiphase DCDC converter 10 is in a boosting operation, the following processing is performed for each converter unit 11 in this embodiment.

  As processing for each converter unit 11, in the present embodiment, first, processing of step S11 is performed. In step S11, the frequency change request unit 340 requests the control unit 18 to change the switching frequency of the target converter unit 11 to a frequency f1 (f1 <f0) lower than the normal frequency f0. Here, it is assumed that the diagnosis unit 320 sequentially selects the target converter unit 11, and the frequency change request unit 340 inputs information on the target converter unit 11 from the diagnosis unit 320. In response to a request from the frequency change request unit 340 to the control unit 18, only the target converter unit 11 performs a switching operation at the low frequency f1, and the other converter units 11 perform a switching operation at the normal frequency f0.

  After the switching frequency of the target converter unit 11 is lowered, the processes in steps S2 to S7 are performed in the same manner as in the first embodiment. In addition to this, in the present embodiment, the converter unit whose switching frequency is reduced in step S11 before the process of the monitoring cycle is ended, regardless of whether the voltage fluctuation is detected or not detected. 11 is performed for switching operation at a normal frequency f0.

  Specifically, after step S4, which is a process when voltage fluctuation is detected, the frequency change request unit 340 controls the control unit to return the switching frequency of the target converter unit 11 to the normal frequency f0 as step S12. 18 to request. If no voltage fluctuation is detected, when it is determined in step S6 that the non-detection time Td is less than the failure determination time Tc, the switching frequency of the target converter unit 11 is set to the normal frequency f0 in step S13. The frequency change request unit 340 requests the control unit 18 to return. When the target converter unit 11 has two or more FETs 12, the processes of steps S2 to S7 and steps S12 and S13 are sequentially performed on all the FETs 12, and any one of the failed FETs 12 is detected. Then, it is determined that the converter unit 11 is out of order.

  Since the control unit 18 of the multi-phase DCDC converter 10 can arbitrarily change the switching frequency of each FET 12, the switching frequency f1 after being lowered can be set to a frequency that is not easily affected by noise. As a result, the DCDC converter failure diagnosis apparatus 300 can accurately detect the failed FET 12 and the converter unit 11 having the FET 12.

  In addition, since the control unit 18 can arbitrarily change the switching cycle for the FET 12 of each converter unit 11, for example, control such as a pulse skip mode in which the on / off operation is stopped for a certain period is also possible. Thereby, control that suppresses ripple of the output voltage is also possible.

  In addition, the description in this Embodiment shows an example of the DCDC converter fault diagnostic apparatus and fault diagnostic method which concern on this invention, and is not limited to this. The detailed configuration and detailed operation of the DCDC converter failure diagnosis apparatus and failure diagnosis method in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Battery 10, 20, 30 Multiphase type DCDC converter 11, 21, 31 Converter part 12 FET
13 Coil 14 Diode 15 Input end 16 Output end 17a, 17b Capacitor 18 Control unit 100, 200, 300 DCDC converter fault diagnosis device 110, 210 Voltage detection unit 120, 220, 320 Diagnosis unit 130 Notification unit 340 Frequency change request unit

Claims (12)

DCDC converter failure detecting a failure of a DCDC converter, comprising two or more converter portions connected in parallel with each other having a switching portion, and a control portion for controlling the switching portion to operate at a predetermined switching period A diagnostic device,
A voltage detection unit for detecting a voltage of the switching unit of each of the two or more converter units;
Monitoring whether the voltage input to the voltage detection unit satisfies a predetermined voltage fluctuation condition, and determining that the voltage does not satisfy the voltage fluctuation condition, the corresponding switching unit and converter unit are determined to be faulty provided with a diagnosis unit that, the,
The voltage detection unit detects a differential voltage between the gate / drain or the gate / source of the switching unit during the step-up operation or the step-down operation of the DCDC converter,
The diagnosis unit monitors whether the differential voltage input from the voltage detection unit is lower than a predetermined threshold during the step-up operation or step-down operation of the DCDC converter as the voltage fluctuation condition, and the differential voltage Is determined to be greater than or equal to the threshold value , the DCDC converter fault diagnosis device is characterized in that the corresponding switching unit and converter unit are determined to be faulty.   DCDC converter failure detecting a failure of a DCDC converter, comprising two or more converter portions connected in parallel with each other having a switching portion, and a control portion for controlling the switching portion to operate at a predetermined switching period A diagnostic device,
  A voltage detection unit for detecting a voltage of the switching unit of each of the two or more converter units;
  Monitoring whether the voltage input to the voltage detection unit satisfies a predetermined voltage fluctuation condition, and determining that the voltage does not satisfy the voltage fluctuation condition, the corresponding switching unit and converter unit are determined to be faulty And a diagnosis unit
  The control unit can be controlled by individually changing the switching period for each converter unit,
  A frequency change request unit that requests the control unit to lengthen the switching cycle of the converter unit to be monitored by the diagnostic unit for the voltage variation condition;
  The diagnosis unit sequentially selects one from the two or more converter units one by one, and makes the switching cycle of the selected converter unit longer by a predetermined period by the frequency change request unit to detect a failure of the DCDC converter
  A DCDC converter fault diagnosis apparatus characterized by the above. The diagnosis unit monitors whether the voltage input from the voltage detection unit is fluctuating in synchronization with the switching period during the step-up or step-down operation of the DCDC converter as the voltage fluctuation condition monitoring, 3. When it is determined that a time during which the voltage does not change in synchronization with the switching period has reached a predetermined failure determination time, the corresponding switching unit and converter unit are determined to be failed. The DCDC converter fault diagnosis apparatus of description. The DCDC converter failure diagnosis apparatus according to claim 3 , wherein the failure determination time is set to be equal to or longer than the switching cycle. Variation of the voltage, according to claim 3, characterized in that it is detected by using an edge detection method or the polling method or phase compensation write signal detection method for detecting a synchronization with the switching period, and either DCDC converter fault diagnosis device. The control unit can be controlled by individually changing the switching period for each converter unit,
A frequency change request unit that requests the control unit to lengthen the switching cycle of the converter unit to be monitored by the diagnostic unit for the voltage variation condition;
The diagnosis unit sequentially selects one from the two or more converter units one by one, and makes the switching cycle of the selected converter unit longer by a predetermined period by the frequency change request unit to detect a failure of the DCDC converter The DC / DC converter fault diagnosis apparatus according to claim 1 . DCDC converter failure detecting a failure of a DCDC converter, comprising two or more converter portions connected in parallel with each other having a switching portion, and a control portion for controlling the switching portion to operate at a predetermined switching period A diagnostic method,
A voltage detection step of detecting a voltage of the switching unit of each of the two or more converter units;
The voltage detected in the voltage detection step is input to monitor whether a predetermined voltage fluctuation condition is satisfied, and when it is determined that the voltage does not satisfy the voltage fluctuation condition, the corresponding switching unit and converter unit are possess failure and a determining diagnosis step, the,
In the voltage detection step, the DCDC converter detects a differential voltage between the gate / drain or the gate / source of the switching unit during the step-up operation or the step-down operation.
In the diagnosis step, whether the differential voltage detected in the voltage detection step during the step-up operation or step-down operation of the DCDC converter is lower than a predetermined threshold is monitored as the voltage variation condition, Is determined to be equal to or greater than the threshold , the DCDC converter fault diagnosis method is characterized in that the corresponding switching unit and converter unit are determined to be faulty.   DCDC converter failure detecting a failure of a DCDC converter, comprising two or more converter portions connected in parallel with each other having a switching portion, and a control portion for controlling the switching portion to operate at a predetermined switching period A diagnostic method,
  A voltage detection step of detecting a voltage of the switching unit of each of the two or more converter units;
  The voltage detected in the voltage detection step is input to monitor whether a predetermined voltage fluctuation condition is satisfied, and when it is determined that the voltage does not satisfy the voltage fluctuation condition, the corresponding switching unit and converter unit are A diagnostic step for determining a failure,
  The control unit can be controlled by individually changing the switching period for each converter unit,
  In the diagnosis step, failure detection of the DCDC converter is performed after the control unit is requested to sequentially select one from the two or more converter units one by one, and to increase the switching period of the selected converter unit by a certain period. I do
  A DCDC converter fault diagnosis method characterized by the above. In the diagnosing step, as the monitoring of the voltage fluctuation condition, the DCDC converter monitors whether the voltage detected in the voltage detecting step is changing in synchronization with the switching period during the step-up operation or the step-down operation. When the time in which the voltage does not vary in synchronism with the switching period is determined to reach a predetermined failure determination time, to claim 8, wherein the determining a failure of the switching unit and the converter unit corresponding The DCDC converter fault diagnostic method of description. The failure determination time, DCDC converter failure diagnosis method according to claim 9, characterized in that configured on the switching frequency Ki以. Variation of the voltage, according to claim 9, characterized in that it is detected by using an edge detection method or the polling method or phase compensation write signal detection method for detecting a synchronization with the switching period, and either DCDC converter fault diagnosis method. The control unit can be controlled by individually changing the switching period for each converter unit,
In the diagnosis step, failure detection of the DCDC converter is performed after the control unit is requested to sequentially select one from the two or more converter units one by one, and to increase the switching period of the selected converter unit by a certain period. The DCDC converter fault diagnosis method according to claim 7, wherein:

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