JP6627633B2 - Control device for power converter - Google Patents

Description

  The present invention relates to a control device for a power converter.

  2. Description of the Related Art Conventionally, as disclosed in Patent Document 1 below, a control device applied to a vehicle including a boost converter and an inverter as a power converter for driving a traveling motor is known. In this control device, for example, when an abnormality occurs in the boost converter, the power converter is cut off. Here, if the cutoff process is executed, the traveling motor cannot be driven, and the vehicle cannot be evacuated. Therefore, in the above-described control device, when the evacuation traveling permission signal of the vehicle is input after the execution of the cutoff process, the cutoff process is canceled and the motor is driven.

JP 2007-236013 A

  Incidentally, an open failure may occur in a switching element included in the power converter. In this case, there is a concern that the operation of the power converter cannot be continued and, for example, power cannot be supplied from the power converter to the motor. As described above, there is still room for improvement in a technique for coping with a case where an open failure occurs in a switching element included in a power converter.

  SUMMARY OF THE INVENTION It is a main object of the present invention to provide a power converter control device capable of continuing operation of a power converter even when an open failure occurs in a switching element included in the power converter.

  Hereinafter, the means for solving the above-mentioned problems and the effects thereof will be described.

  The present invention has a switch unit (20UH to 20WL; 50CH, 50CL) including a parallel connection of a plurality of switching elements (SUHA to SWLB; SCHA to SCLB), and each of the plurality of switching elements is individually provided. Is applied to a power converter (20; 50) that converts an input voltage to a predetermined voltage by driving the switching element and outputs the converted voltage, and determines whether or not an open failure of the switching element has occurred. When the failure determination unit determines that an open failure has occurred, the failure determination unit performs a process of limiting the current flowing through the switch unit more than when it is determined that no open failure has occurred. While performing the current limiting process with the current limiting unit (30), an open fault among the plurality of switching elements is detected. Flip Not and failure-time driver for driving the determined switching element (30), characterized in that it comprises a.

  In the above invention, each of the plurality of switching elements constituting the switch unit can be individually driven. For this reason, among the plurality of switching elements, it is possible to drive switching elements other than the switching element for which the failure determination unit has determined that the open failure has occurred. Thereby, the operation of the power converter can be continued.

  Here, in a switch section including a parallel connection of a plurality of switching elements, when an open failure occurs in a part of these switching elements, a current flowing in the switch section is borne by a switching element having no open failure. It becomes. In this case, the amount of current carried per switching element is larger than when the current flowing through the switch section is carried by each of the switching elements. As a result, there is a concern that the reliability of the switching element is reduced.

  In this regard, in the above invention, when the failure determination unit determines that an open failure has occurred, it performs a process of limiting the current flowing to the switch unit more than when it is determined that the open failure has not occurred. Of the switching elements determined to have not caused an open failure. For this reason, the amount of current carried by one switching element when an open failure occurs can be limited, and a reduction in the reliability of the switching element can be avoided while continuing the operation of the power converter.

1 is an overall configuration diagram of a vehicle-mounted motor control system according to a first embodiment. FIG. 4 is a diagram showing current and voltage characteristics of a MOSFET and an IGBT. FIG. 4 is a block diagram illustrating a motor control process. The figure which shows the relationship between an electric angular velocity and a torque limit value. 5 is a flowchart illustrating a procedure of a failure determination process. FIG. 3 is a circuit diagram showing an example of a failure occurrence mode. 9 is a flowchart illustrating a procedure of a torque limiting process. The figure which shows the setting method of the torque limit value according to the switch in which the open failure occurred. The figure which shows the setting method of the torque limit value based on the temperature of a switching element. 9 is a flowchart illustrating a procedure of a torque limiting process according to the second embodiment. FIG. 3 is a circuit diagram showing an example of a failure occurrence mode. FIG. 9 is a diagram illustrating a configuration for determining an open failure according to a third embodiment. 5 is a flowchart illustrating a procedure of a failure determination process. The whole block diagram of the vehicle-mounted motor control system which concerns on 4th Embodiment. FIG. 4 is a block diagram showing control processing of the boost converter. The figure which shows the relationship of actual total electric power, electric power limit value, etc. 9 is a flowchart illustrating a procedure of an upper arm side failure determination process of the boost converter. 9 is a flowchart illustrating a procedure of a lower arm side failure determination process of the boost converter. 9 is a flowchart illustrating a procedure of a torque limiting process. The figure which shows the setting method of the electric power limit value according to the switch in which the open failure occurred. The figure which shows the setting method of the electric power limit value based on the temperature of a switching element. 15 is a flowchart illustrating a procedure of a torque limiting process according to a fifth embodiment.

(1st Embodiment)
Hereinafter, a first embodiment in which a control device according to the present invention is mounted on a vehicle such as an electric vehicle including a rotating electric machine as a vehicle-mounted main unit will be described with reference to the drawings.

  As shown in FIG. 1, the motor control system includes a motor generator 10, an inverter 20 as a DC / AC converter, and a control device 30. The motor generator 10 is an in-vehicle main engine, and is capable of transmitting power to the drive wheels 40. In the present embodiment, a three-phase motor generator is used. In the present embodiment, a permanent magnet synchronous machine such as IPMSM or SPMSM is used as the motor generator 10.

  Motor generator 10 is connected to battery 21 as a DC power supply via inverter 20 as a power converter. The output voltage of the battery 21 is, for example, 100 V or more. A smoothing capacitor 22 for smoothing the input voltage of the inverter 20 is provided between the battery 21 and the inverter 20.

  The inverter 20 includes each switch unit. Specifically, the inverter 20 includes a series connection of a U-phase upper arm switch unit 20UH and a U-phase lower arm switch unit 20UL. The U-phase upper-arm switch unit 20UH includes a parallel connection of a U-phase first upper-arm switching element SUHA and a U-phase second upper-arm switching element SUHB. The U-phase lower arm switch section 20UL includes a parallel connection of a U-phase first lower arm switching element SULA and a U-phase second lower arm switching element SULB. U-phase first lower arm switching element SULA and U-phase second lower arm switching element SULB are respectively connected to the low potential side terminals of U-phase first upper arm switching element SUHA and U-phase second upper arm switching element SUHB. Are connected.

  Inverter 20 includes a series connection of V-phase upper arm switch unit 20VH and V-phase lower arm switch unit 20VL. The V-phase upper arm switch section 20VH includes a parallel connection of a V-phase first upper arm switching element SVHA and a V-phase second upper arm switching element SVHB. The V-phase lower arm switch section 20VL includes a parallel connection of a V-phase first lower arm switching element SVLA and a V-phase second lower arm switching element SVLB.

  Inverter 20 includes a series connection of W-phase upper arm switch unit 20WH and W-phase lower arm switch unit 20WL. The W-phase upper arm switch section 20WH includes a parallel connection of a W-phase first upper arm switching element SWHA and a W-phase second upper arm switching element SWHB. The W-phase lower arm switch unit 20WL includes a parallel connection of a W-phase first lower arm switching element SWLA and a W-phase second lower arm switching element SWLB.

  In the present embodiment, IGBTs as Si devices are used as the first switching elements SUHA, SULA, SVHA, SVLA, SWHA, SWLA. For this reason, in each first switching element, the low potential side terminal is an emitter and the high potential side terminal is a collector. In this embodiment, an N-channel MOSFET as a SiC device is used as each of the second switching elements SUHB, SULB, SVHB, SVLB, SWHB, SWLB. For this reason, in each second switching element, the low potential side terminal is a source and the high potential side terminal is a drain.

  In addition, a freewheel diode is connected in anti-parallel to each of the first switching elements SUHA, SULA, SVHA, SVLA, SWHA, SWLA. A parasitic diode is formed in each of the second switching elements SUHB, SULB, SVHB, SVLB, SWHB, SWLB. Incidentally, a freewheel diode may be connected in anti-parallel to each second switching element. Further, the IGBT and the MOSFET connected in parallel to each other may be formed in the same package, or may be formed in different packages.

  In the present embodiment, each switch section is configured by a parallel connection of an IGBT and a MOSFET because a current flows through a MOSFET having a low on-resistance in a low current region to reduce a loss in a low current region. That's why. That is, as shown in FIG. 2, in a low current region where the current is smaller than the predetermined current Ith, the on-resistance of the MOSFET is smaller than the on-resistance of the IGBT. For this reason, in the low current region, more current flows through the MOSFET out of the MOSFET and the IGBT connected in parallel with each other. On the other hand, in a large current region where the current is larger than the predetermined current Ith, the ON resistance of the IGBT is smaller than the ON resistance of the MOSFET. For this reason, in the large current region, of the MOSFET and the IGBT connected in parallel to each other, more current flows to the IGBT. In the low current region, only the MOSFET of the IGBT and the MOSFET may be driven.

  Further, in the present embodiment, the maximum value of the collector current Ic that can flow through each of the first switching elements SUHA, SULA, SVHA, SVLA, SWHA, SWLA is determined by each of the second switching elements SUHB, SULB, SVHB, SVLB, SWHB, SWLB. Is set to be larger than the maximum value of the drain current Id that can flow through the drain.

  Returning to the description of FIG. 1, the U-phase of the motor generator 10 is connected to a connection point between the U-phase upper arm switch unit 20UH and the U-phase lower arm switch unit 20UL. The V-phase of the motor generator 10 is connected to a connection point between the V-phase upper arm switch section 20VH and the V-phase lower arm switch section 20VL. The W-phase of the motor generator 10 is connected to a connection point between the W-phase upper arm switch section 20WH and the W-phase lower arm switch section 20WL.

  The control system includes a voltage detector 23, a phase current detector 24, and an angle detector 25. The voltage detector 23 detects an input voltage of the inverter 20. Phase current detection section 24 detects at least two phase currents among the phase currents flowing through motor generator 10. Angle detecting section 25 detects electric angle θe of motor generator 10. As the angle detection unit 25, for example, a resolver can be used.

  The detection values of the voltage detection unit 23, the phase current detection unit 24, and the angle detection unit 25 are input to the control device 30. Control device 30 is mainly configured by a microcomputer, and drives inverter 20 to control the control amount of motor generator 10 to the command value. In the present embodiment, the control amount is a torque, and the command value thereof is a torque command value Trq *. More specifically, the control device 30 controls the voltage detection unit 23 to turn on and off the switching elements SUHA, SUHB, SULA, SULB, SVHA, SVHB, SVLA, SVLB, SWHA, SWHB, SWLA, SWLB constituting the inverter 20. Each drive signal GUHA, GUHB, GULA, GULB, GVHA, GVHB, GVLA, GVLB, GWHA, GWHB, GWLA, GWLB is generated based on the detection values of the phase current detection unit 24 and the angle detection unit 25. The drive signal is output to the corresponding gate drive circuit of each switching element. Here, the upper arm drive signals GUHA, GUHB, GVHA, GVHB, GWHA, GWHB and the corresponding lower arm drive signals GULA, GULB, GULB, GVLB, GVLB, GWLA, GWLB are complementary to each other. Has become. That is, the upper arm switching element and the corresponding lower arm switching element are alternately turned on.

  Subsequently, torque control of motor generator 10 performed by control device 30 will be described with reference to FIG. In the present embodiment, the torque of motor generator 10 is controlled to torque command value Trq * by current feedback control.

  The two-phase conversion unit 30a converts the U, V, and W phase currents in the three-phase fixed coordinate system based on the phase current detected by the phase current detection unit 24 and the electrical angle θe detected by the angle detection unit 25. It is converted into a d-axis current Idr and a q-axis current Iqr in a two-phase rotating coordinate system (dq coordinate system).

  The first low-pass filter 30b removes high-frequency components from the d-axis current Idr calculated by the two-phase converter 30a. The second low-pass filter 30c removes high frequency components from the q-axis current Iqr calculated by the two-phase converter 30a.

  Speed calculating section 30d calculates electric angular velocity ω of motor generator 10 based on electric angle θe detected by angle detecting section 25.

  Control calculation unit 30e calculates torque command value Trq * of motor generator 10 based on vehicle information input from outside control device 30 and input voltage VINV detected by voltage detection unit 23. The vehicle information includes, for example, information such as the traveling speed of the vehicle and the amount of accelerator operation by the user.

  When determining that the calculated torque command value Trq * exceeds the torque limit value Tlim as the control amount limit value, the control calculation unit 30e limits the torque command value Trq * with the torque limit value Tlim. In the present embodiment, as shown in FIG. 4, the torque limit value Tlim takes a constant value when the electric angular velocity ω is equal to or lower than a predetermined angular velocity, and when the electric angular velocity ω is equal to or higher than the predetermined angular velocity, The higher the value, the smaller the value.

  The command current calculation unit 30f calculates a d-axis command current Id *, which is a current command value in a two-phase rotating coordinate system, based on the torque command value Trq * output from the control calculation unit 30e and the electric angular velocity ω, and q The axis command current Iq * is calculated. The d-axis command current Id * and the q-axis command current Iq * are, for example, a map in which the torque command value Trq * and the electric angular velocity ω are associated with the d-axis command current Id * and the q-axis command current Iq *. It should just be calculated using.

  The d-axis deviation calculator 30g calculates the d-axis current deviation ΔId by subtracting the output value of the first low-pass filter 30b from the d-axis command current Id *. The q-axis deviation calculator 30h calculates the q-axis current deviation ΔIq by subtracting the output value of the second low-pass filter 30c from the q-axis command current Iq *.

  The d-axis command voltage calculation unit 30i calculates the d-axis command voltage Vd * as an operation amount for performing feedback control of the output value of the first low-pass filter 30b to the d-axis command current Id *. The q-axis command voltage calculator 30j calculates the q-axis command voltage Vq * as an operation amount for performing feedback control of the output value of the second low-pass filter 30c to the q-axis command current Iq *. In this embodiment, proportional-integral control is used as the feedback control.

  Based on the d-axis command voltage Vd * and the q-axis command voltage Vq *, the amplitude / phase calculator 30k calculates a voltage amplitude Vn that is the magnitude of the voltage vector Vr of the inverter 20 and a voltage phase δ that is the phase of the voltage vector Vr. Is calculated. In the present embodiment, the voltage phase δ is defined based on the positive direction of the q-axis, and a counterclockwise direction from this reference is defined as the positive direction.

  The INV signal generation unit 30m generates the respective drive signals GUHA, GUHB, GULA, GULB, GVHA, GVHB, GVLA, GVLB, GWHA, GWHB, GWLA, and GWLB based on the voltage amplitude Vn, the voltage phase δ, and the input voltage VINV. I do. In the present embodiment, each drive signal is generated by a method described below.

  First, the INV signal generation unit 30m calculates a modulation rate M that is a value obtained by normalizing the voltage amplitude Vn with the input voltage VINV. Specifically, the modulation rate M is calculated by dividing the voltage amplitude Vn by “１ ／” of the input voltage VINV. Then, the INV signal generation unit 30m stores, as map data, the waveform (pulse pattern) of the drive signal in one cycle of the electrical angle for each modulation factor M. The INV signal generation unit 30m selects a pulse pattern corresponding to the calculated modulation factor M. The INV signal generation unit 30m generates a drive signal by setting the output timing of the selected pulse pattern based on the voltage phase δ.

  In this embodiment, the two switching elements constituting each switch section are basically turned on or turned off at the same time. For this reason, the drive signals corresponding to the two switching elements constituting each switch section are basically simultaneously turned on or off. For example, the drive signal GUHA of the U-phase first upper arm switching element SUHA and the drive signal GUHB of the U-phase second upper arm switching element SUHB are the same drive command.

  The failure determination unit 30n determines whether a failure has occurred in each switching element included in the inverter 20 based on the drive signal generated by the INV signal generation unit 30m and the phase current detected by the phase current detection unit 24. Is determined.

  FIG. 5 shows a procedure of a failure determination process according to the present embodiment. This process is executed when the failure determination unit 30n determines that a predetermined execution condition is satisfied. The predetermined execution condition is, for example, a condition that the control system is activated, an individual fail condition, or a collective fail condition. Here, the individual fail condition refers to information indicating that a failure has occurred in any one of the switching elements in a configuration in which a signal transmission path is individually provided to the control device 30 corresponding to the switching element configuring the inverter 20. This is a condition that the information has been obtained through individual signal transmission paths. In addition, the collective failure condition means that in a configuration in which a common signal transmission path is provided to the control device 30 corresponding to the switching elements forming the inverter 20, information indicating that a failure has occurred in any of the switching elements is common. Is obtained via the signal transmission path.

  In this series of processing, first, in step S10, any one of the upper arm switching elements SUHA, SUHB, SVHA, SVHB, SWHA, SWHB constituting the inverter 20 and the lower arm switching elements SULA, SULB constituting the inverter 20. , SVLA, SVLB, SWLA, and SWLB. Then, an ON drive command is output from the INV signal generator 30m as a drive signal for the selected two switching elements. Here, as the combination of the two switching elements, upper- and lower-arm switching elements of the same phase, such as a U-phase first upper-arm switching element SUHA and a U-phase second lower-arm switching element SULB, are excluded from the ON drive targets. This is to prevent a short circuit current from flowing through the switching element.

  In the following steps S11 and S12, it is determined based on the detection result of the phase current by the phase current detection unit 24 whether the selected switching element is normal or whether the selected switching element has an open fault or a short fault. .

  Specifically, when it is determined that a current flows in the two phases that are turned on, it is determined that the two selected switching elements are normal. FIG. 6A shows an example in which the U-phase first upper arm switching element SUHA and the W-phase first lower arm switching element SWLA are selected as ON drive targets. In this example, it is determined that a current has flowed in the U and W phases based on the detection value of the phase current detection unit 24, and the U-phase first upper arm switching element SUHA and the W-phase first lower arm switching element SWLA are normal. It is determined that there is. FIG. 6 shows the switching elements in a simplified manner. In FIG. 6, reference numerals are given to only some of the components.

  On the other hand, if it is determined that no current flows through the two phases that have been turned on, it is determined that an open failure has occurred in one of the two selected switching elements. FIG. 6B shows an open failure in the W-phase first lower arm switching element SWLA when the U-phase first upper arm switching element SUHA and the W-phase first lower arm switching element SWLA are selected as ON drive targets. The following shows an example in which is generated. In this example, it is determined that no current flows in any of the phases, and that an open failure has occurred in any of the U-phase first upper arm switching element SUHA and the W-phase first lower arm switching element SWLA. Is determined.

  On the other hand, if it is determined that a current has flowed into a phase other than the two phases that have been turned on, it is determined that a short-circuit fault has occurred in one of the switching elements that constitute the phase that is not turned on. FIG. 6C shows a short-circuit fault in the W-phase first lower arm switching element SWLA when the U-phase first upper arm switching element SUHA and the V-phase first lower arm switching element SVLA are selected as ON drive targets. The following shows an example in which is generated. In this example, it is determined that a current has also flowed into the W-phase other than the U- and V-phases that have been turned on, and it is determined that a short-circuit fault has occurred in any of the switching elements constituting the W-phase.

  Returning to the description of FIG. 5, in step S13, the processes of steps S10 to S12 are completed for all combinations of the upper and lower arm switching elements other than the combination of the upper and lower arm switching elements of the same phase. It is determined whether or not. Until an affirmative determination is made in step S13, the upper and lower arm switching elements that are turned on are switched. This makes it possible to determine which of the switching elements included in the inverter 20 has an open failure.

  Next, the torque limiting process executed by the control calculation unit 30e will be described. This processing is performed to make the controllability of the motor generator 10 equal to the controllability in a normal state where no open failure occurs even when an open failure occurs in a switching element included in the inverter 20. .

  In other words, conventionally, when an open fault occurs in the switching element constituting the inverter 20, for example, three-phase ON control for turning on the three-phase switching element on the same arm side or driving of the two-phase switching element is performed. In some cases, phase drive control is performed as a fail-safe operation. However, when performing the three-phase ON control, there is a problem that the torque control of the motor generator 10 cannot be performed. In addition, when performing two-phase drive control, problems such as an increase in torque ripple of the motor generator 10 and a deterioration in torque responsiveness occur. As described above, in the related art, the controllability of the motor generator 10 is reduced, and there is a concern that the evacuation traveling of the vehicle may be hindered. In the present embodiment, the above-described torque limiting process is performed in order to solve such a problem that occurs at the time of the open failure and to make the vehicle safely evacuate.

  FIG. 7 shows the procedure of the torque limiting process. This process is repeatedly performed at a predetermined cycle, for example.

  In this series of processing, first, in step S20, based on the determination result obtained from the failure determination unit 30n, it is determined whether or not there is a short-circuit failure or an open failure among the switching elements included in the inverter 20. Is determined.

  If it is determined in step S20 that there is no switching element in which a short-circuit failure or an open failure has occurred, the process proceeds to step S21, in which the torque limit value Tlim is set in the manner shown in FIG. A normal traveling process including a normal drive control process is performed.

  On the other hand, if it is determined in step S20 that there is a switching element in which a short failure or an open failure has occurred, the process proceeds to step S22. In step S22, it is determined whether the failure mode of the failed switching element is a short-circuit failure. If it is determined in step S22 that the failure mode is not the short-circuit failure, the process proceeds to step S23, and it is determined whether the logical product of the first condition and the second condition is true. Here, the first condition is a condition that among the switch units 20UH, 20VH, 20WH, 20UL, 20VL, and 20WL constituting the inverter 20, there is only one switch unit including a switching element in which an open failure has occurred. is there. The second condition is a condition that, in the switch unit including the switching element in which the open failure has occurred, the switching element in which the open failure has occurred is one of the first switching element (IGBT) and the second switching element (MOSFET). is there.

  If it is determined in step S22 that the failure mode is a short-circuit failure, or if a negative determination is made in step S23, the process proceeds to step S24 to perform a process of stopping the operation of the inverter 20 and stopping the running of the vehicle.

  On the other hand, if an affirmative determination is made in step S23, the process proceeds to step S25 to determine whether or not the switching element having the open failure is the first switching element (IGBT) in the switch section including the switching element in which the open failure has occurred. I do.

  If a negative determination is made in step S25, the switching element having the open failure is determined to be the second switching element (MOSFET), and the process proceeds to step S26. In step S26, as shown in FIG. 8A, a torque limit value Tlim is set based on the electrical angular velocity ω and the input voltage VINV. Specifically, the torque limit value Tlim set in step S26 is smaller than the torque limit value Tlim shown in FIG. Here, the predetermined angular velocity, which is the upper limit of the electrical angular velocity ω at which the torque limit value Tlim is a constant value, is reduced as the input voltage VINV is lower.

  After the process of step S26 is completed, the drive signal corresponding to the second switching element is set as an off-drive command, and a command to drive the first switching element is output to the INV signal generation unit 30m. Thus, in the switch section including the second switching element in which the open failure has occurred, the on / off driving of the first switching element in which the open failure has not occurred can be continued.

  Returning to the description of FIG. 7, when the affirmative determination is made in step S25, the switching element having the open failure is determined to be the first switching element (IGBT), and the process proceeds to step S27. In step S27, as shown in FIG. 8B, the torque limit value Tlim is set based on the electric angular velocity ω and the input voltage VINV. Specifically, the torque limit value Tlim set in step S27 is smaller than the torque limit value Tlim set in step S26.

  After the completion of the process in step S27, the drive signal corresponding to the first switching element is set as an off-drive command, and a command to drive the second switching element is output to the INV signal generation unit 30m. Accordingly, in the switch section including the first switching element in which the open failure has occurred, the on / off driving of the second switching element in which the open failure has not occurred can be continued.

  When the processes in steps S21, S24, S26, and S27 are completed, the process returns to step S20.

  In steps S26 and S27, the torque limit value Tlim may be set by further using the temperature of the switching element. Specifically, as shown in FIG. 9, the higher the temperature of the switching element, the lower the torque limit value Tlim may be set. Here, the temperature of the switching element may be detected by a temperature detecting unit such as a temperature-sensitive diode or a thermistor.

  According to the embodiment described above, the following effects can be obtained.

  Each of the two switching elements constituting each of the switch units 20UH to 20WL can be individually driven. Therefore, even if an open failure occurs in one of the two switching elements, the other switching element can be turned on and off. Thus, the operation of the inverter 20 can be continued, and the traveling of the vehicle can be continued. As a result, it is possible to safely perform the limp-home running of the vehicle and extend the evacuation running distance.

  When it is determined that an open failure has occurred, the torque limit value Tlim is set smaller than when it is determined that no open failure has occurred. For this reason, when an open fault occurs, the amount of current carried by one switching element included in the inverter 20 can be limited, and the reliability of the switching element can be avoided while the operation of the inverter 20 is continued.

  By changing the torque limit value Tlim, the current flowing through the switch unit was limited. Therefore, the current can be easily limited. Further, the drive of the motor generator 10 can be continued with the same controllability as in the normal state at the time of the open failure without changing the current feedback control in the control device 30 before and after the open failure.

  The torque limit value Tlim was set based on the electric angular velocity ω and the input voltage VINV. Therefore, torque command value Trq * can be accurately limited according to the driving state of motor generator 10.

  The torque limit value Tlim when it is determined that an open failure has occurred in the first switching element (IGBT) having a large maximum current value among the two switching elements constituting the switch section, and the second switching element having a small maximum current value. (MOSFET) is set to be smaller than the torque limit value Tlim when it is determined that an open failure has occurred. Thus, the torque limit value Tlim can be appropriately set based on the specifications of the switching element, and the current flowing through the switching element can be appropriately limited.

(2nd Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In the present embodiment, as shown in FIG. 10, the torque limiting process executed by the control calculation unit 30e is changed. In FIG. 10, the same processes as those shown in FIG. 7 are denoted by the same reference numerals for convenience.

  In this series of processing, if a negative determination is made in step S22, the process proceeds to step S30. In step S30, it is determined whether or not both the first switching element (IGBT) and the second switching element (MOSFET) of any one of the switch units included in the inverter 20 have an open failure. This processing is performed when both the first and second switching elements of one of the switch units have an open failure, such as when both the U-phase first upper arm switching element SUHA and the U-phase second upper arm switching element SUHB open. Except for the case, the operation is performed to continue the running of the vehicle. FIG. 11A shows a case where the U-phase first and second upper arm switching elements SUHA and SUHB have an open failure as an example of a case where the determination is affirmative in step S30. FIG. 11B shows a case where the U-phase second upper arm switching element SUHB and the V-phase second lower arm switching element SVLB have an open failure as an example of a case where a negative determination is made in step S30. .

  If an affirmative determination is made in step S30, it is determined that both the first and second switching elements of one of the switch units have an open failure, and the process proceeds to step S24.

  On the other hand, if a negative determination is made in step S30, the process proceeds to step S31, and it is determined whether the first switching element (IGBT) is included in the switching element in which the open failure has occurred. Here, FIG. 11C shows an example in which a positive determination is made in step S31. FIG. 11B shows an example in which a negative determination is made in step S31.

  If a negative determination is made in step S31, the process proceeds to step S26. On the other hand, when an affirmative determination is made in step S31, the process proceeds to step S27. Incidentally, in steps S26 and S27, the torque limit value Tlim may be set using the temperature of the switching element as described in the first embodiment.

  According to the present embodiment described above, when it is determined that an open failure of any of the first and second switching elements has occurred in each of the two or more switch units, the first switching element (IGBT) has an open failure. The torque limit value Tlim in the case where it is determined to have been set is set smaller than the torque limit value Tlim in the case where it is determined that the second switching element (MOSFET) has an open failure. Thereby, it is possible to avoid a decrease in the reliability of the switching element while continuing the operation of the inverter 20.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, a method of determining an open failure of a switching element included in the inverter 20 is changed. Specifically, it is determined whether or not an open failure has occurred based on the potential difference between the high potential side terminal and the low potential side terminal of the switching element.

  FIG. 12 shows an abnormality determination unit 26 that determines an open failure. In the present embodiment, the abnormality determination unit 26 is provided individually corresponding to each switching element. Each abnormality determination unit 26 receives a drive signal corresponding to the abnormality determination unit 26 from the INV signal generation unit 30m. The determination result of each abnormality determination unit 26 is input to the failure determination unit 30n. FIG. 12 illustrates an abnormality determination unit 26 corresponding to the U-phase first upper arm switching element SUHA. In the example illustrated in FIG. 12, the abnormality determination unit 26 acquires the collector-emitter voltage Vce of the U-phase first upper arm switching element SUHA, and determines whether there is an open failure based on the acquired collector-emitter voltage Vce. judge.

  FIG. 13 shows a failure determination process performed by the abnormality determination unit 26. In FIG. 13, the U-phase first upper arm switching element SUHA will be described as an example.

  In this series of processing, first, in step S40, it is determined whether or not the drive signal GUHA is an ON drive command.

  If an affirmative determination is made in step S40, the process proceeds to step S41, in which it is determined whether the acquired collector-emitter voltage Vce is higher than the ON voltage Von of the U-phase first upper arm switching element SUHA. Here, the ON voltage Von may be set to the maximum value of the collector-emitter voltage Vce assumed when the U-phase first upper arm switching element SUHA is in the ON state.

  When an affirmative determination is made in step S41, the process proceeds to step S42, and it is determined that the U-phase first upper arm switching element SUHA has an open failure.

  The failure determination unit 30n determines which switching element has an open failure based on the determination result obtained from each abnormality determination unit 26.

  According to the present embodiment described above, the same effects as in the first embodiment can be obtained.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In the present embodiment, as shown in FIG. 14, a control system including two sets of a motor generator and an inverter is used. In FIG. 14, the same components as those shown in FIG. 1 are denoted by the same reference numerals for convenience.

  As illustrated, the control system includes a boost converter 50, a first inverter 20a, a first motor generator 10a, a second inverter 20b, a second motor generator 10b, and an engine 60 as a vehicle-mounted main engine. The engine 60, the first motor generator 10a, and the second motor generator 10b are connected by a power split mechanism 61, and the drive wheels 40 are connected to the output shaft of the second motor generator 10b. In the present embodiment, the same permanent magnet synchronous machine as the motor generator 10 of the first embodiment is used as each of the motor generators 10a and 10b. In the present embodiment, the boost converter 50, the first inverter 20a, and the second inverter 20b correspond to a power converter. In addition, the first inverter 20a and the second inverter 20b correspond to electric devices.

  The boost converter 50 includes a first capacitor 51, a reactor 52, and a second capacitor 53. In addition, boost converter 50 includes an upper arm transformation switch unit 50CH and a lower arm transformation switch unit 50CL.

  The upper-arm transformation switch unit 50CH includes a parallel connection of a first upper-arm transformation switching element SCHA and a second upper-arm transformation switching element SCHB. The lower arm transformation switch unit 50CL includes a parallel connection of a first lower arm transformation switching element SCLA and a second lower arm transformation switching element SCLB. The low potential side terminals of the first upper arm transformation switching element SCHA and the second upper arm transformation switching element SCLB are connected to the respective high potential sides of the first lower arm transformation switching element SCLA and the second lower arm transformation switching element SCLB. Terminal is connected.

  In the present embodiment, an IGBT is used as the first upper and lower arm transforming switching elements SCHA and SCLA, and an N-channel MOSFET is used as the second upper and lower arm transforming switching elements SCHB and SCLB. Freewheel diodes DHA and DLA are connected in anti-parallel to the first upper and lower arm transformation switching elements SCHA and SCLA. Parasitic diodes DHB and DLB are formed in the second upper and lower arm transformation switching elements SCHB and SCLB. Incidentally, a freewheel diode may be connected in anti-parallel to the second upper and lower arm transformation switching elements SCHB and SCLB. Further, the IGBT and the MOSFET connected in parallel to each other may be formed in the same package, or may be formed in different packages.

  In the present embodiment, the reason that each of the switch units 50CH and 50CL is configured by a parallel connection of the IGBT and the MOSFET is to reduce the loss in the low current region as in the first embodiment.

  In this embodiment, the maximum value of the collector current Ic that can flow through the first upper and lower arm transformation switching elements SCHA and SCLA is the maximum value of the drain current Id that can flow through the second upper and lower arm transformation switching elements SCHB and SCLB. It is set higher than the maximum value.

  A second capacitor 53 is connected in parallel to a series connection of the upper arm transformation switch unit 50CH and the lower arm transformation switch unit 50CL. A first end of the reactor 52 is connected to a connection point between the upper arm transformation switch unit 50CH and the lower arm transformation switch unit 50CL, and a positive terminal of the battery 21 is connected to a second end of the reactor 52. The negative terminal of the battery 21 is connected to the emitter of the first lower arm transformer switching element SCLA and the source of the second lower arm transformer switching element SCLB. A first capacitor 51 is connected to the battery 21 in parallel.

  The first inverter 20a and the second inverter 20b are connected to the second capacitor 53 side of the boost converter 50. The first motor generator 10a is connected to the first inverter 20a. The first motor generator 10a is connected to the engine 60 via a power split device 61, and serves as a generator and a starter for the engine 60. The second motor generator 10b is connected to the second inverter 20b. The second motor generator 10b plays a role of an in-vehicle main engine and the like, similarly to the motor generator 10 of the first embodiment. The configuration of each of the inverters 20a and 20b is the same as the configuration of the inverter 20 of the first embodiment, and a detailed description thereof will be omitted.

  The control system includes a first voltage detector 70 for detecting an input voltage of the boost converter 50, a second voltage detector 71 for detecting an input voltage of each of the inverters 20a and 20b, and a reactor current for detecting a current flowing through the reactor 52. And a detection unit 72. Further, the control system includes a first phase current detection unit 24a, a second phase current detection unit 24b, a first angle detection unit 25a, and a second angle detection unit 25b. The first and second phase current detectors 24a and 24b detect at least two phase currents among the respective phase currents flowing through the first and second motor generators 10a and 10b. First and second angle detectors 25a and 25b detect electrical angles θe1 and θe2 of first and second motor generators 10a and 10b.

  The detection value of each detection unit is input to the control device 30. Control device 30 drives first inverter 20a to control the torque of first motor generator 10a to the first torque command value, and controls the first inverter 20a to control the torque of second motor generator 10b to the second torque command value. 2 drives the inverter 20b. At this time, boost converter 50 is also driven. In boost converter 50, first and second lower arm transformation switching elements SCLA and SCLB and first and second upper arm transformation switching elements SCHA and SCHB are alternately turned on.

  In order to drive each of the transformation switching elements in the above-described manner, control device 30 generates drive signals GCHA, GCLB, GCLA, and GCLB for each of transformation switching elements SCHA, SCHB, SCLA, and SCLB constituting boost converter 50, Each of the generated drive signals is output to the corresponding gate drive circuit of each of the transformation switching elements.

  Incidentally, the control device 30 drives the first inverter 20a based on the detection values of the first phase current detection unit 24a and the first angle detection unit 25a, and detects the second phase current detection unit 24b and the detection of the second angle detection unit 25b. The second inverter 20b is driven based on the value. Further, when an open failure occurs in each of the first inverter 20a and the second inverter 20b, the control device 30 performs the same torque limiting process as in the first embodiment. However, in the present embodiment, a detailed description of these processes is omitted.

  Next, the boosting process when the boosting converter 50 is driven in power mode will be described with reference to FIG. This processing is executed by the control device 30.

  The command value calculation unit 80a calculates a total power command value P *, which is a total value of command output powers of the first inverter 20a and the second inverter 20b, based on the vehicle information. The first torque command value is set based on the command output power of the first inverter 20a, and the second torque command value is set based on the command output power of the second inverter 20b. Incidentally, the total power command value P * may be calculated in consideration of the loss of each inverter 20a, 20b and each motor generator 10a, 10b.

  Command value calculation section 80a calculates a command output voltage VH *, which is a command value of the output voltage of boost converter 50, based on the calculated total power command value P *, as shown in FIG. In the present embodiment, the command output voltage VH * is set to the first voltage VH1 when the total power command value P * is equal to or lower than the first predetermined value P1, and the total power command value P * is equal to or higher than the first predetermined value P1. Is set higher as the total power command value P * is larger. Command output voltage VH * is set to second voltage VH2 higher than first voltage VH1 when total power command value P * is equal to or higher than second predetermined value P2 that is higher than first predetermined value P1. .

  The command value calculation unit 80a calculates an actual total power value Pr that is a total value of the actual output power of each of the first inverter 20a and the second inverter 20b. When determining that the calculated actual total power value Pr exceeds the power limit value Plim, the command value calculation unit 80a limits the actual total power value Pr with the power limit value Plim as shown in FIG. Then, the first inverter 20a and the second inverter 20b are driven. When the actual total power value Pr is limited, the first torque command value and the second torque command value are set again based on the restricted actual total power value Pr.

  The voltage deviation calculator 80b calculates the voltage deviation ΔV by subtracting the input voltage VHr detected by the second voltage detector 71 from the command output voltage VH *.

  The FB duty ratio setting unit 80c calculates a duty ratio (= Ton / Tsw), which is a ratio of the ON drive period Ton per one switching cycle Tsw, based on the proportional integral control using the voltage deviation ΔV as an input. Hereinafter, the duty ratio set by the FB duty ratio setting unit 80c is referred to as a feedback duty ratio Dutyfb.

  The FF duty ratio setting unit 80d calculates a feedforward duty ratio Dutyff as a feedforward manipulated variable based on the command output voltage VH * and the input voltage VLr detected by the first voltage detection unit 70. In the present embodiment, the feedforward duty ratio Dutyff is calculated using the following equation (1).

時比率加算部８０ｅは、フィードフォワード時比率Ｄｕｔｙｆｆとフィードバック時比率Ｄｕｔｙｆｂとの加算値として、指令時比率Ｄｕｔｙを算出する。

The duty ratio adding unit 80e calculates the command duty ratio Duty as an addition value of the feedforward duty ratio Dutyff and the feedback duty ratio Dutyfb.

  The CNV signal generation section 80f generates the drive signals GCHA, GCHB, GCLA, GCLB based on the command duty ratio Duty. In the present embodiment, the drive signals GCHA, GCHL, GCLA, and GCLB are generated by PWM processing based on the magnitude comparison between the command duty ratio Duty and a carrier such as a triangular wave.

  Subsequently, a failure determination process performed by a failure determination unit included in the control device 30 will be described. This process is performed when the failure determination unit determines that the predetermined execution condition is satisfied.

  First, a failure determination method for the first and second upper arm transformation switching elements SCHA and SCHB constituting the boost converter 50 will be described with reference to FIG.

  In this series of processing, first, in step S50, the first and second inverters 20a and 20b are operated to perform regenerative driving in which power is supplied from the first and second inverters 20a and 20b to the battery 21 via the boost converter 50. The inverters 20a and 20b are controlled.

  In a succeeding step S51, drive signals GCHA and GCNB corresponding to either one of the first and second upper arm transformation switching elements SCHA and SCHB are set as ON drive commands.

  In a succeeding step S52, a current flowing through the on-drive transformation switching element is detected. In the present embodiment, a sense current output from a sense terminal provided in the transformation switching element is detected.

  In the following step S53, it is determined based on the current detection result whether the selected transformer is normal or whether the selected transformer has an open failure. More specifically, when it is determined that the current flows through the transformation switching element that has been turned on, it is determined that the selected transformation switching element is normal. On the other hand, when it is determined that no current flows through the ON-driven transformation switching element, it is determined that an open failure has occurred in the selected transformation switching element.

  In a succeeding step S54, it is determined whether or not the processing in steps S50 to S53 has been completed for each of the first and second upper arm transformation switching elements SCHA and SCHB.

  The determination of the short-circuit failure according to the present embodiment may be performed, for example, as described below. More specifically, the drive signals GCHA and GCNB corresponding to either one of the first and second upper arm transformer switching elements SCHA and SCHB are set to the off drive command. Then, when it is determined that a current has flowed through the off-driven transformer switching element, it is determined that a short-circuit fault has occurred in the selected transformer switching element.

  Subsequently, a failure determination method of the first and second lower-arm transformation switching elements SCLA and SCLB included in the boost converter 50 will be described with reference to FIG.

  In this series of processing, first, in step S60, the first and second motors are driven to supply power from the battery 21 to the first and second inverters 20a and 20b via the boost converter 50. The inverters 20a and 20b are controlled.

  In a succeeding step S61, drive signals GCLA, GCLB corresponding to one of the first and second lower arm transformation switching elements SCLA, SCLB are set to an ON drive command.

  In a succeeding step S62, a current flowing through the ON-driven transformation switching element is detected. In the present embodiment, a sense current output from a sense terminal provided in the transformation switching element is detected.

  In the following step S63, it is determined based on the current detection result whether the selected transformer is normal or whether the selected transformer has an open failure. More specifically, when it is determined that the current flows through the transformation switching element that has been turned on, it is determined that the selected transformation switching element is normal. On the other hand, when it is determined that no current flows through the ON-driven transformation switching element, it is determined that an open failure has occurred in the selected transformation switching element.

  In a succeeding step S64, it is determined whether or not the processing of steps S60 to S63 has been completed for each of the first and second lower arm transformation switching elements SCLA and SCLB.

  The determination of the short-circuit failure according to the present embodiment may be performed, for example, as described below. More specifically, the drive signals GCLA and GCLB corresponding to one of the first and second lower arm transformation switching elements SCLA and SCLB are set as off-drive commands. Then, when it is determined that a current has flowed through the off-driven transformer switching element, it is determined that a short-circuit fault has occurred in the selected transformer switching element.

  Next, the power limiting process executed by the command value calculating unit 80a will be described with reference to FIG. This process is repeatedly performed at a predetermined cycle, for example.

  In this series of processing, first, in step S70, based on the determination result obtained from the failure determination unit, it is determined whether or not there is a short-circuit failure or an open failure in each of the transformer switching elements included in boost converter 50. Is determined.

  If it is determined in step S70 that there is no transformer switching element in which a short failure or an open failure has occurred, the process proceeds to step S71, in which the command output voltage VH * is set in the manner described with reference to FIG. And a normal drive control process including a normal drive control process for boost converter 50. At this time, a normal drive control process for each of the inverters 20a and 20b is also performed.

  On the other hand, if it is determined in step S70 that there is a transformer switching element in which a short failure or an open failure has occurred, the process proceeds to step S72. In step S72, it is determined whether or not the failure mode of the failed transformer switching element is a short-circuit failure. If it is determined in step S72 that the failure mode is not a short-circuit failure, the process proceeds to step S73, in which one of the upper-arm transformation switch unit 50CH and the lower-arm transformation switch unit 50CL detects the first failure-switching switching element. It is determined whether it is one of the transformation switching element (IGBT) and the second transformation switching element (MOSFET).

  If it is determined in step S72 that the failure mode is a short-circuit failure, or if a negative determination is made in step S73, the process proceeds to step S74, in which the operations of the boost converter 50 and the inverters 20a and 20b are stopped to drive the vehicle. Perform processing to stop.

  On the other hand, when an affirmative determination is made in step S73, the process proceeds to step S75, and in the switch unit including the transformer switching element in which the open failure has occurred, whether the transformer switching element in which the open failure has occurred is the first switching element (IGBT). Is determined.

  If a negative determination is made in step S75, the variable-voltage switching element having the open failure is determined to be the second switching element (MOSFET), and the process proceeds to step S76. In step S76, as shown in FIG. 20 (a-1), the power limit value Plim is made smaller than the value shown in FIG. 16 (b). Further, as shown in FIG. 20 (a-2), the total power command value P * at which the command output voltage VH * starts to increase is made smaller than the total power command value P shown in FIG. 16 (b). .

  Returning to the description of FIG. 19, when the affirmative determination is made in step S75, it is determined that the open-circuit-failure variable switching element is the first switching element (IGBT), and the process proceeds to step S77. In step S77, as shown in FIG. 20 (b-1), the power limit value Plim is made smaller than the value shown in FIG. 20 (a-1). Also, as shown in FIG. 20 (b-2), the total power command value P * at which the command output voltage VH * starts to increase is made smaller than the total power command value P shown in FIG. 20 (a-2). .

  When the processes of steps S71, S74, S76, and S77 are completed, the process returns to step S70.

  Incidentally, in steps S76 and S77, the power limit value Plim and the command output voltage VH * may be set by further using the temperature of the transformer. More specifically, as shown in FIG. 21A, the higher the temperature of the transformation switching element, the smaller the power limit value Plim may be. Further, as shown in FIG. 21B, the higher the temperature of the transformation switching element, the smaller the total power command value P * at which the command output voltage VH * starts to increase. Here, the temperature of the transformation switching element may be detected by a temperature detection unit such as a temperature-sensitive diode or a thermistor.

  As described above, in the present embodiment, the current flowing through the voltage transformation switch unit is limited by changing the power limit value Plim. For this reason, the drive of the boost converter 50 can be continued with the same controllability as in the normal state at the time of the open failure without changing the boost processing method in the control device 30 before and after the open failure of the variable voltage switching element. Thus, unlike a conventional technique in which, for example, the operation of the step-up converter 50 is stopped when an open failure occurs in the transformation switching element, the output voltage of the battery 21 is stepped up and supplied to the inverters 20a and 20b. It is possible to continue charging the battery 21 with regenerative power from the inverters 20a and 20b. As a result, the traveling distance of the vehicle during the evacuation traveling can be extended.

(Fifth embodiment)
Hereinafter, the fifth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In the present embodiment, as shown in FIG. 22, the power limiting process executed by the command value calculation unit 80a is changed. In FIG. 22, the same processes as those shown in FIG. 19 are denoted by the same reference numerals for convenience.

  In this series of processing, if a negative determination is made in step S72, the process proceeds to step S80. In step S80, it is determined whether or not both the first switching element (IGBT) and the second switching element (MOSFET) have an open failure in one of the upper and lower arm transformation switch sections 50CH and 50CL. judge. This processing is performed unless both the first and second transformer switching elements constituting one switch unit have an open failure, for example, both the first and second upper arm transformer switching elements SCHA and SCHB have an open failure. This is done to keep the vehicle running.

  If an affirmative determination is made in step S80, it is determined that both of the first and second transforming switching elements in one of the upper and lower arm transforming switch units 50CH and 50CL have an open failure, and the flow proceeds to step S74.

  On the other hand, if a negative determination is made in step S80, the process proceeds to step S81, and it is determined whether or not the switching element having the open failure includes the first transformation switching element (IGBT). If a negative determination is made in step S81, the process proceeds to step S76. On the other hand, when an affirmative determination is made in step S81, the process proceeds to step S77. Incidentally, in steps S76 and S77, the power limit value Plim may be set using the temperature of the switching element as described in the fourth embodiment.

  According to the present embodiment described above, it is possible to avoid a decrease in the reliability of the variable voltage switching element while continuing the operation of the boost converter 50.

(Other embodiments)
The above embodiments may be modified as follows.

  In the fourth and fifth embodiments, the open failure determination method described in the third embodiment may be used.

  In the first embodiment, when the specifications of the switching elements of the respective switch units are the same, the process of changing the torque limit value Tlim is not divided into the processes of steps S26 and S27 in FIG. Only one process. For example, when the switching element of each switch unit is an IGBT, the processes of steps S25 to S27 may be omitted, and the process of step S26 may be performed if an affirmative determination is made in step S23. The same applies to the second to fifth embodiments.

In the first embodiment, the torque limit value Tlim is changed by the method shown in FIG. 8, but the present invention is not limited to this. For example, the torque limit value Tlim may be changed using the equation shown in the following equation (1).
Tlim = K × φ × I (1)
In the above equation (1), K indicates a coefficient, φ indicates the magnetic flux density of the rotor of the motor generator, and I indicates the current flowing through the motor generator. Here, the torque limit value Tlim may be limited by limiting the current I. In the above equation (1), the torque limit value Tlim may be changed using a mathematical expression that includes reluctance torque in addition to the magnet torque.

  In the failure determination processing of the first embodiment, the detection value of the phase current detection unit 24 is used, but the invention is not limited to this. For example, a sense current output from a sense terminal provided in a switching element included in the inverter 20 may be used for a failure determination process.

  In the first embodiment, as the method of limiting the current flowing to the motor generator, a method of limiting the torque command value Trq * with the torque limit value Tlim is employed, but the present invention is not limited to this. For example, a method of limiting the phase current detected by the phase current detection unit with a current limit value may be adopted. In this case, the current limit value may be set smaller as the input voltage VINV is lower.

  In the first embodiment, the torque limit value Tlim may be set based on one of the electrical angular velocity ω and the input voltage VINV.

  -In step S24 of FIG. 10 of the second embodiment, three-phase ON control or two-phase drive control may be performed.

  In the step S74 of FIG. 19 of the fourth embodiment, when it is determined that both the first and second upper-arm transformation switching elements SCHA and SCHB have an open failure, the vehicle may continue traveling. This is because power can be supplied from the battery 21 to the inverters 20a and 20b via the diodes DHA and DHB, although the first and second upper-arm transformation switching elements SCHA and SCHB have an open failure.

  The number of switching elements constituting each switch unit is not limited to two, but may be three or more. Here, when the number of switching elements is three or more, not only a configuration in which all of the switching elements determined to have not caused an open failure among a plurality of switching elements forming each switch unit are subjected to on / off driving, but also a part thereof. A configuration may be adopted in which the switching elements are turned on and off.

  In the fourth embodiment, the failure of the transformer is determined based on the sense current. However, the present invention is not limited to this. For example, the failure may be determined based on the reactor current detected by the reactor current detector 72.

  In the configuration of the first embodiment shown in FIG. 3, the first and second low-pass filters 30b and 30c may not be provided.

  In the above embodiments, the detection value of the temperature detection unit is used as the temperature of the switching element for limiting the current, but the invention is not limited to this. For example, the temperature of a cooling fluid (water temperature) for cooling the switching element, or the temperature of the switching element estimated from the case temperature of an inverter as a power converter may be used.

  The switching elements constituting each switch unit are not limited to the combination of the IGBT and the MOSFET, but may be other combinations.

  The control amount of the motor generator is not limited to the torque, and may be, for example, a rotation speed. The motor generator is not limited to a three-phase motor generator, but may be a one-phase, two-phase, or four-phase motor generator.

  The method of controlling the control amount of the motor generator to the command value is not limited to the method using current feedback control, but may be, for example, a method using torque feedback control.

  The DC / DC converter is not limited to the one having the single upper / lower arm switch shown in FIG. 14 of the fourth embodiment, and may be, for example, a converter having a plurality of upper / lower arm switches. Further, the DCDC converter is not limited to the one having the upper and lower arm switch parts connected in series to each other, but may be one having a single switch part.

  The DC / DC converter is not limited to the boost converter, and may be, for example, a step-down converter that steps down an input DC voltage and outputs the stepped down DC voltage.

  The power converter is not limited to an inverter or a DCDC converter. For example, an ACAC converter (matrix converter) that converts an input AC voltage into a predetermined AC voltage and outputs the converted AC voltage may be used.

  In the fourth and fourth embodiments, the number of sets of the motor generator and the inverter may be three or more.

  The motor generator is not limited to a permanent magnet synchronous machine, but may be, for example, a winding field type synchronous machine. Further, the motor generator is not limited to a synchronous machine, but may be, for example, an induction machine. Further, the motor generator is not limited to a motor generator used as a vehicle-mounted main engine, and may be a motor generator used for other applications such as an electric power steering device and an electric motor constituting an air-conditioning electric compressor.

  10 ... motor generator, 20 ... inverter, 30 ... control device.

Claims (12)

A switching unit (20UH to 20WL; 50CH, 50CL) including a parallel connection of a plurality of switching elements (SUHA to SWLB; SCHA to SCLB), and each of the plurality of switching elements can be individually driven; And a power converter control device applied to a power converter (20; 50) that converts an input voltage to a predetermined voltage by driving the switching element and outputs the converted voltage.
The power converter includes a DC / AC converter (20) that converts an input DC voltage into an AC voltage and outputs the AC voltage to a multi-phase rotating electric machine (10).
The DC / AC converter includes a switch unit (20UH to 20WH) including a parallel connection of upper arm switching elements (SUHA to SWHB) as the switching element, and the switching element connected in series to the upper arm switching element. The switch units (20UL to 20WL) each including a parallel connection of lower arm switching elements (SULA to SWLB) as the number of phases of the rotating electric machine;
A DC / AC drive unit (30) for driving the upper arm switching element and the lower arm switching element to control the control amount of the rotating electric machine to the command value;
A failure determination unit (30) for determining whether an open failure of the switching element has occurred;
When the failure determination unit determines that an open failure has occurred, the control amount limit value as the limit value of the current flowing through the switch unit is smaller than when it is determined that the open failure has not occurred. A current limiter (30) for performing a process of limiting the command value with a control amount limit value;
A failure drive unit (30) that drives a switching element that has been determined not to have an open failure among the plurality of switching elements, while performing a process of limiting the command value with the control amount limit value. ,
Each of the switch units is configured by the switching element having a different maximum current value that can flow,
The current limiter variably sets the control amount limit value based on the input voltage of the DC / AC converter and information on the switching element that has been determined by the failure determiner that no open failure has occurred. Control device for power converter. The current limiting unit sets the constant control amount limit value when the electric angular velocity of the rotating electric machine is equal to or less than a predetermined angular velocity, and when the electric angular velocity is equal to or more than the predetermined angular velocity, the higher the electric angular velocity The control amount limit value is set small,
The power converter according to claim 1, wherein the current limiter sets the predetermined angular velocity lower as the input voltage of the DC / AC converter is lower, when the failure determiner determines that an open failure has occurred. Vessel control device. The power converter includes a DCDC converter (50) that transforms and outputs an input DC voltage,
The DCDC converter includes a switch section (50CH) including a parallel connection of upper arm transformation switching elements (SCHA, SCHB) as the switching elements, and a switching element as the switching element connected in series to the upper arm transformation switching element. The switch unit (50CL) including a parallel connection of lower arm transformation switching elements (SCLA, SCLB);
The control device for a power converter according to claim 1 or 2, further comprising a DCDC drive unit (30) that drives the switching element included in the DCDC converter to control an output voltage of the DCDC converter to a command voltage. One or more electric devices (20a, 20b) to which output power of the DCDC converter is supplied are connected to an output side of the DCDC converter,
The electric device, the output power of which is controlled to the command output power,
4. The control device for a power converter according to claim 3, wherein the current limiter performs a process of limiting a sum of output powers of the electric device with a power limit value as the current limit value. 5. A switching unit (20UH to 20WL; 50CH, 50CL) including a parallel connection of a plurality of switching elements (SUHA to SWLB; SCHA to SCLB), and each of the plurality of switching elements can be individually driven; And a power converter control device applied to a power converter (20; 50) that converts an input voltage to a predetermined voltage by driving the switching element and outputs the converted voltage.
A failure determination unit (30) for determining whether an open failure of the switching element has occurred;
When the failure determination unit determines that an open failure has occurred, the current limiting unit (30) performs a process of reducing the limit value of the current flowing through the switch unit as compared with the case where it is determined that the open failure has not occurred. )When,
A failure drive unit (30) that drives a switching element that is determined not to have an open failure among the plurality of switching elements, while performing a process of reducing the current limit value;
Each of the switch units is configured by the switching element having a different maximum current value that can flow,
The control device for a power converter, wherein the current limiter variably sets the current limit value further using information on the switching element determined by the failure determiner that no open failure has occurred. The current limiting unit is configured to limit the current in a case where the failure determination unit determines that an open failure has occurred in a switching element having the largest maximum current value among the plurality of switching elements included in the switch unit. The value according to any one of claims 1 to 5, wherein the value is set to be smaller than the current limit value when the failure determination unit determines that an open failure has occurred in the switching element having the smaller maximum current value. A control device for the power converter according to claim 1. The current limiting unit is configured such that, when it is determined by the failure determination unit that an open failure of the switching element has occurred in each of the two or more switch units, the maximum current is supplied to the switching element that is determined to have an open failure. The limit value of the current in the case where the switching element having a larger value is included, in the case where the switching element in which the maximum current value is larger is not included in the switching element in which it is determined that an open failure has occurred. 7. The control device for a power converter according to claim 6 , wherein the control value is set to be smaller than the current limit value. The control device for a power converter according to any one of claims 1 to 7 , wherein the current limiter variably sets the current limit value by further using a temperature of the switching element. A current detection unit that detects a current flowing through the switching element,
It said failure determining unit includes a drive signal of the switching element, based on the current detected by the current detection unit, any one of claims 1-8 determines whether the open failure has occurred 3. The control device for a power converter according to claim 1. The power converter includes a DCDC converter (50) that transforms an input DC voltage and outputs the transformed DC voltage to electric devices (20a, 20b).
The DCDC converter includes a switch section (50CH) including a parallel connection of upper arm transformation switching elements (SCHA, SCHB) as the switching elements, and a switching element as the switching element connected in series to the upper arm transformation switching element. The switch unit (50CL) including a parallel connection of lower arm transformation switching elements (SCLA, SCLB);
The current detection unit detects a current flowing through the upper arm transformation switching element,
In the state where the electric device is controlled so that power is supplied from the electric device to the DCDC converter, the failure determination unit determines that no current flows in the upper arm transformer switching element that has been driven on. The control device for a power converter according to claim 9, wherein when it is determined, it is determined that an open failure has occurred in the upper arm transformer switching element that has been driven on. The power converter includes a DCDC converter (50) that transforms an input DC voltage and outputs the converted DC voltage to one or more electric devices (20a, 20b).
The DCDC converter includes a switch section (50CH) including a parallel connection of upper arm transformation switching elements (SCHA, SCHB) as the switching elements, and a switching element as the switching element connected in series to the upper arm transformation switching element. The switch unit (50CL) including a parallel connection of lower arm transformation switching elements (SCLA, SCLB);
The current detection unit detects a current flowing in the lower arm transformation switching element,
In the state where the electric device is controlled so that power is supplied from the DCDC converter to the electric device, the failure determination unit determines that no current flows through the lower arm transformation switching element that has been driven ON. The control device for a power converter according to claim 9 or 10, wherein when the determination is made, it is determined that an open failure has occurred in the lower arm transformer switching element that has been driven on. A voltage detection unit that detects a voltage between the input and output terminals of the switching element,
It said failure determining unit includes a drive signal of the switching element, based on the detected voltage by the voltage detecting section, one of the determining claims 1-8 whether open failure in the switching element is generated The control device for a power converter according to claim 1.

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