JP2013121202A - Control device for multi-phase rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a multi-phase rotary machine capable of avoiding that a rotational speed region of a motor generator 10 that can specify short circuit failures of switching elements Sjp and Sjn (j=u, v, and w) is restricted.SOLUTION: Under a situation where all switching elements Sjp and Sjn provided in an inverter IV are operated to be in an off state, a phase current is sampled at every 90° of an electric angle of a motor generator 10, and a determination current for each phase is calculated as an average value of four phase currents sampled in one cycle of the phase current. On the basis of an absolute value and polarity of the determination current for each phase, it is specified in which one of the all switching elements Sjp and Sjn provided in the inverter IV short circuit failures occur. Then, three-phase short circuit processing for turning on all switching elements on a side specified that the short circuit failures occur among the high potential side switching elements Sjp and the low potential side switching elements Sjn is performed.

Description

  The present invention relates to a control device for a multi-phase rotating machine that controls a multi-phase rotating machine by turning on and off a pair of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the multi-phase inverter.

  Conventionally, a technique for controlling a three-phase motor by turning on and off a pair of switching elements corresponding to each phase of an inverter connected to a DC power source is well known. Here, when a short-circuit failure occurs in any of the switching elements included in the inverter, both the switching element in which the short-circuit failure has occurred and the switching element connected in series to the switching element are turned on. A through current flows from the power source to these switching elements, which may reduce the reliability of the switching elements and the like.

  In order to avoid such a situation, a technique for turning off all the switching elements included in the inverter when a short circuit failure of the switching element occurs is known, as seen in Patent Document 1 below.

  By the way, the following Patent Document 1 also describes a technique for identifying a switching element in which a short circuit failure has occurred among switching elements included in an inverter. In this technology, the absolute value of the DC component of the current flowing in the phase of the switching element in which the short-circuit fault occurred is short-circuited under the condition that all switching elements provided in the inverter are turned off and the motor rotates without load. Switching element in which the absolute value of the DC component of the current flowing in the phase of the switching element in which no fault occurs and the polarity of the DC component in the current flowing in the phase of the switching element in which the short fault has occurred This utilizes the difference from the polarity of the direct current component of the current flowing in the phase.

  Specifically, in this technology, first, a smoothing process (low-pass filter) is used to calculate a value corresponding to the DC component of these phase currents from each phase current as a smoothed value, and the largest of these calculated smoothed values. The phase (maximum current phase) corresponding to is determined. Then, based on the maximum current phase and the polarity of the annealing value, the switching element in which the short circuit failure has occurred is specified.

  As a technique for identifying a switching element in which a short circuit failure has occurred based on the absolute value and polarity of the direct current component of the phase current, there is one described in Patent Document 2 below.

JP 2009-278791 A JP 2010-158089 A

  By the way, in the technique described in the said patent document 1, as above-mentioned, in order to calculate the annealing value from a phase current, a low-pass filter is used. Here, the frequency of the phase current tends to increase as the rotational speed of the motor increases. For this reason, in order to appropriately calculate the smoothed value from the phase current according to the phase current frequency, it is required to set the time constant of the low-pass filter according to the phase current frequency. In this case, there is a concern about an increase in the man-hours required for designing the low-pass filter. On the other hand, if the time constant of the low-pass filter is fixed, for example, in order to avoid an increase in the adaptation man-hours, the rotational speed range of the motor that can calculate the smoothed value from the phase current is restricted, and as a result, a short circuit failure of the switching element There is a concern that the rotational speed region in which the location can be specified is restricted.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to control a multi-phase rotating machine that can suitably avoid the limitation of the rotating speed region of the rotating machine that can identify a short-circuit failure point of the switching element. To provide an apparatus.

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

  The invention according to claim 1 is a controller for a multi-phase rotating machine that controls a multi-phase rotating machine by turning on and off a pair of high-potential side switching elements and low-potential side switching elements corresponding to each phase of the multi-phase inverter. In the state where all the high-potential side switching elements and the low-potential side switching elements included in the inverter are turned off, the electrical angle of the rotating machine for each phase current flowing between the inverter and the rotating machine Calculating means for calculating a DC component equivalent amount based on values at each of a plurality of timings related to the switching element, and the switching element included in the inverter based on the DC component equivalent amount of each phase calculated by the calculating means Short-circuit fault specifying means for specifying the short-circuit fault location.

  In the above invention, by providing the calculation means, under the situation where all the switching elements included in the inverter are turned off, each phase current is based on the value at each of a plurality of timings related to the electrical angle of the rotating machine. Calculate the DC component equivalent. The DC component equivalent amount is not calculated based on, for example, the phase current sampled every predetermined time, but is calculated based on the phase current at each of a plurality of timings related to the electrical angle. Regardless of the frequency of the current, the value corresponds to the DC component of the phase current.

  Here, the DC component equivalent amount of each phase is a parameter for specifying the short-circuit fault location of the switching element. This is due to the following reason. If these switching elements are turned off in a state where no short-circuit fault has occurred in all the switching elements included in the inverter, basically no phase current flows. On the other hand, a phase current flows under a situation where a short circuit failure occurs in any of the switching elements. Here, the absolute value and polarity of the DC component of the current of each phase are determined depending on which of all the switching elements has a short-circuit fault. For this reason, the DC component equivalent amount of each phase is a parameter for specifying a short-circuit fault location.

  Thus, in the above invention, the short-circuit fault location of the switching element can be specified based on the DC component equivalent amount of each phase that has a value corresponding to the DC component of the phase current regardless of the frequency of the phase current. Thereby, it can avoid suitably that the rotational speed area | region of the rotary machine which can pinpoint the short circuit failure location of a switching element is restrict | limited.

  According to a second aspect of the present invention, in the first aspect of the invention, the calculation unit calculates an average value of the values at each of the plurality of timings as the DC component equivalent amount, and the short-circuit fault identification unit includes: A short-circuit fault location of the switching element is specified based on the calculated average value of each phase.

  The invention according to claim 3 is the invention according to claim 1, wherein the calculation means calculates a total value of the values at each of the plurality of timings as the DC component equivalent amount, and the short-circuit fault identification means A short-circuit fault location of the switching element is specified based on the calculated total value of each phase.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the calculation means includes a pair of phase currents separated by a time interval that is an odd multiple of a half cycle of the phase current. The DC component equivalent amount is calculated based on one set or a plurality of sets of values.

  In the above invention, for each phase current, the DC component equivalent amount is calculated based on one set or a plurality of sets of a pair of values separated by a time interval obtained by multiplying a half period of the phase current (for example, the fundamental wave component of the phase current) by an odd number. To do. According to the DC component equivalent calculated in this way, the value related to the DC component of the phase current can be grasped more appropriately regardless of the frequency of the phase current.

  In addition, when the said invention has the invention specific matter of invention of Claim 2, the said calculation means should just calculate the average value of one set or several sets of said pair of values as said DC component equivalent amount. The average value thus calculated approximates the DC component of the phase current.

  In addition, when the invention has the invention specific matter of the invention according to claim 3, the calculation means may calculate a total value of one or a plurality of sets of the pair of values as the DC component equivalent amount. The total value thus calculated is a value proportional to the DC component of the phase current.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the calculation means, for each phase current, is based on one or more sets of the maximum value and the minimum value of the phase current, and the maximum value and the minimum value. Is calculated as the DC component equivalent amount, and the short-circuit fault specifying means specifies a short-circuit fault location of the switching element based on the calculated median value of each phase.

  In the above invention, for each phase current, the median value of the maximum value and the minimum value is calculated based on one or more sets of the maximum value and the minimum value of the phase current. The median value thus calculated approximates the DC component of the phase current.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the calculation means calculates the DC component equivalent amount based on the phase current within one cycle of the phase current. It is characterized by doing.

  In the above invention, by calculating the DC component equivalent amount in the above-described mode, it is possible to avoid an increase in the update period of the DC component equivalent amount, and thus it is possible to quickly identify the short-circuit fault location of the switching element.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the short-circuit fault specifying means corresponds to the DC component corresponding amount of each phase having the largest absolute value. It is specified that a short circuit fault has occurred in the switching element of the phase.

  The absolute value of the DC component equivalent amount corresponding to the phase of the switching element in which the short-circuit failure has occurred is larger than the absolute value of the DC component equivalent amount corresponding to the phase of the switching element in which the short-circuit failure has not occurred. In view of this point, in the above-described invention, a short-circuit failure has occurred in either the high-potential side switching element or the low-potential side switching element of the phase corresponding to the largest DC component equivalent amount of each phase. Can be specified.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the short-circuit fault specifying means is configured to select the high-potential side switching element based on the polarity of the DC component equivalent amount of each phase. And which of the low-potential side switching elements is identified as having a short-circuit fault.

  The polarity corresponding to the DC component corresponding to the phase of the switching element in which the short-circuit failure has occurred is different from the polarity corresponding to the DC component corresponding to the phase of the switching element in which the short-circuit failure has not occurred. In view of this point, in the above-described invention, it is possible to specify which of the high potential side switching element and the low potential side switching element has a short-circuit fault based on the polarity of the DC component equivalent amount of each phase.

  The invention according to claim 9 is the invention according to claim 8, wherein when the short-circuit fault specifying means specifies that a short-circuit fault has occurred, it is specified that a short-circuit fault has occurred between the high potential side and the low potential side. It further comprises short-circuit means for turning on all the switching elements on the other side.

  In the above invention, the short-circuit means is provided to turn on all of the switching elements on the high-potential side and the low-potential side that have been identified as having the short-circuit fault in a situation where a short-circuit fault occurs in the switching element. As a result, the switching elements on the high-potential side and the low-potential side that are identified as having the short-circuit fault are all turned on, and the switching elements that are not identified as having the short-circuit fault are all off. It is said. As a result, the DC component of the phase current of each phase is set to near 0, and the peak value of the absolute value of the phase current can be reduced. Thereby, it can be avoided that the reliability of the rotating machine or the inverter is lowered, for example, the coil is disconnected due to a large current flowing through the coil of the rotating machine.

  According to a tenth aspect of the present invention, in the ninth aspect of the invention, the short-circuit means is turned on until the short-circuit fault is resolved after the short-circuit fault specifying means specifies that the short-circuit fault has occurred. It is characterized by continuing.

  In the said invention, it can avoid that the peak value of the absolute value of a phase current becomes large until the short circuit failure of a switching element is eliminated.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the phase current at the time of a short circuit failure generating. The figure which shows the three-phase short circuit process concerning 1st Embodiment. The flowchart which shows the procedure of the abnormality determination process of the inverter concerning the embodiment. The figure which shows the relationship between the effective value of the phase current concerning the embodiment, and the rotational speed of a motor generator. The flowchart which shows the procedure of the short circuit fault specific process concerning the embodiment. The figure which shows the sampling aspect of the phase current concerning the embodiment. The figure which shows the relationship between the short circuit location of a switching element, and the direct current component of a phase current. The time chart which shows an example of the short circuit fault specific process concerning 1st Embodiment. The figure which shows the sampling aspect of the phase current concerning 2nd Embodiment. The figure which shows the sampling aspect of the phase current concerning 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a control device according to the present invention is applied to a hybrid vehicle including a rotating machine and an internal combustion engine as an in-vehicle main machine will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a system according to the present embodiment.

  As shown, the motor generator 10 is a three-phase rotating machine (for example, an embedded permanent magnet synchronous motor), and includes a stator (not shown) having a U-phase coil 10 u, a V-phase coil 10 v, and a W-phase coil 10 w, and a permanent magnet. And a rotor (not shown). These coils 10 u, 10 v, 10 w are Y-connected by connecting one end of each coil at a neutral point N.

  The output shaft (rotor) of the motor generator 10 is mechanically connected to the output shaft (crankshaft 12a) of the engine 12 and the drive wheels 14 via a power transmission mechanism (not shown).

  Motor generator 10 is electrically connected to inverter IV. Inverter IV is connected to high voltage battery 16 (for example, a lithium ion storage battery), and includes a series connection body (U-phase arm) of switching elements Sup and Sun, a series connection body (V-phase arm) of switching elements Svp and Svn, and a switching element. Three series connection bodies (W-phase arms) of Swp and Swn are connected in parallel. The connection points of the pair of switching elements Sjp (j = u, v, w) and the switching element Sjn are connected to the phase coils 10u, 10v, 10w of the motor generator 10, respectively.

  In the present embodiment, insulated gate bipolar transistors (IGBTs) are used as the switching elements Sjp and Sjn. In the present embodiment, hereinafter, the switching element Sjp is referred to as a high potential side switching element (or upper arm), and the switching element Sjn is referred to as a low potential side switching element (or lower arm).

  Between the input / output terminals (between the collector and the emitter) of the switching element Sjp on the high potential side and the switching element Sjn on the low potential side, the cathodes of the free wheel diode FDjp on the high potential side and the free wheel diode FDjn on the low potential side are provided. And the anode are connected.

  Switching elements Sjp and Sjn are turned on / off by drive unit DU. The drive unit DU is connected to the conduction control terminals (gates) of the switching elements Sjp and Sjn, and detects the potential difference between the collector and emitter of the switching elements Sjp and Sjn, and controls the detected potential difference via the interface 18. It has a function of transmitting to the device 20. The interface 18 is means for exchanging information between these systems while insulating the high voltage system configured by the inverter IV and the like from the low pressure system configured by the control device 20 and the like.

  The control device 20 is composed mainly of a microcomputer and uses a low voltage battery 21 having a lower voltage than a terminal voltage (for example, 100 V or more) of the high voltage battery 16 as a power supply source, and a control amount (for example, torque) of the motor generator 10. Inverter IV is operated to control as desired. Specifically, the control device 20 includes a voltage sensor 22 that detects a voltage at the input terminal of the inverter IV (voltage of the capacitor 23), a current sensor 24 that detects U-phase and W-phase currents iu and iw of the motor generator 10, 26. A detection value of a rotation angle sensor 28 (for example, a resolver) for detecting the electrical angle θ of the motor generator 10 is fetched. Then, the control device 20 performs a process of calculating the V-phase current iv based on the U-phase and W-phase currents iu and iw detected by the current sensors 24 and 26. Further, the control device 20 generates operation signals gjp and gjn for alternately turning on the switching elements Sjp and Sjn for the U phase, V phase and W phase of the inverter IV based on the detection values of the various sensors. And processing to output to the drive unit DU. As a result, the switching elements Sjp and Sjn are turned on / off by the control device 20 via the drive unit DU.

  In particular, when a short circuit failure occurs in either of the switching elements Sjp and Sjn (inverter abnormality occurs), the control device 20 performs a short circuit protection process for forcibly turning off all the switching elements Sjp and Sjn. This process prevents both the switching elements Sjp and Sjn in the in-phase arm from being turned on, so that the positive and negative terminals of the high voltage battery 16 are short-circuited and a through current does not flow through the switching elements Sjp and Sjn. Process. Incidentally, whether or not an inverter abnormality has occurred may be determined based on, for example, whether or not the potential difference between the input / output terminals of the pair of switching elements Sjp and Sjn is very small (0). Further, when the short-circuit protection process is executed, the engine 12 is the only driving power source for the vehicle thereafter.

  By the way, when the rotor of the motor generator 10 is rotated by traveling of the vehicle in a situation where the short-circuit protection process is performed and the drive wheel 14 and the motor generator 10 are in a power transmission state, each phase coil 10u, An induced voltage is applied to 10v and 10w. As a result, phase currents whose phases are shifted from each other by 120 ° flow between the inverter IV and each of the phase coils 10u, 10v, and 10w.

  FIG. 2 shows the transition of each phase current when a short circuit failure occurs in the switching element Sup on the high potential side of the U-phase arm. In the figure, the phase current flowing in the direction from inverter IV to each phase coil 10u, 10v, 10w of motor generator 10 is defined as positive.

  Due to a short circuit failure of the switching element Sup, a current flows in a path passing through the switching element Sup, the U-phase coil 10u, the neutral point N, the V-phase coil 10v, and the free wheel diode FDvp, and the switching element Sup, the U-phase coil 10u, A current flows through a path that passes through the neutral point N, the W-phase coil 10w, and the freewheel diode FDwp. Under such circumstances, as shown in FIG. 2, a phenomenon occurs in which the DC components of the U-phase current iu, V-phase current iv, and W-phase current iw deviate from 0, and the peak value of the absolute value of each phase current is growing.

  Here, depending on the structure of the motor generator 10 such as the magnetic force of the permanent magnet included in the rotor of the motor generator 10 is large, or the number of turns of each phase coil 10u, 10v, 10w is large, each phase current due to a short circuit failure An increase in absolute peak value can be significant. In this case, the reliability of the motor generator 10 and the inverter IV may be reduced, such as the disconnection of the phase coils 10u, 10v, and 10w.

  In order to cope with such a problem, in the present embodiment, a short-circuit fault specifying process is performed to specify which of the switching elements Sjp and Sjn included in the inverter IV has a short-circuit fault. A three-phase short circuit process is performed to turn on all the switching elements on the side specified that a short circuit failure has occurred. According to this process, the side which is not the neutral point N side among both ends of each phase coil 10u, 10v, 10w is mutually short-circuited. As a result, as shown in FIG. 3, the DC components of the U-phase current iu, the V-phase current iv, and the W-phase current iw are made close to 0, thereby reducing the peak value of the absolute value of each phase current. be able to.

  Next, the abnormality determination process of the inverter IV including the short-circuit fault identification process according to the present embodiment will be described.

  FIG. 4 shows the procedure of the abnormality determination process. This process is repeatedly executed by the control device 20 at a predetermined cycle, for example.

  In this series of processes, first, in step S10, it is determined whether or not the short-circuit protection process for forcibly turning off all the switching elements Sjp and Sjn included in the inverter IV is executed due to the occurrence of the inverter abnormality described above. To do.

  If an affirmative determination is made in step S10, the process proceeds to step S12 to determine whether or not a short circuit fault has occurred in either of the switching elements Sjp and Sjn. In the present embodiment, it is determined that a short circuit fault has occurred based on the fact that the absolute value of the phase current is not zero. This determination method is basically based on the fact that no phase current flows when all the switching elements Sjp and Sjn are turned off in a situation where no short-circuit fault has occurred in the switching elements.

  In addition to the fact that the phase current flows when the above-described three-phase short-circuit process is executed, the phase current can flow when the induced voltage applied to each phase coil exceeds the voltage of the high-voltage battery 16. At this time, if a method of determining that a short-circuit fault has occurred based on the fact that the absolute value of the phase current is not 0, the short-circuit fault is detected by detecting the phase current even though the short-circuit fault of the switching element has not occurred. There is a risk of misjudgment that it has occurred. In order to avoid such a situation, for example, a short-circuit fault is based on the fact that the absolute value of the actual phase current is within the range of the assumed fluctuation amount of the absolute value of the phase current when the three-phase short-circuit process is executed. You may employ | adopt the method of judging that this has arisen. This is because the value of the phase current when the three-phase short-circuit process is executed and the value of the phase current when the induced voltage applied to each phase coil exceeds the voltage of the high-voltage battery 16 do not normally overlap. is there.

  Incidentally, the phase current used in the processing of this step may correspond to at least one of the U, V, and W phases. Further, the phase current tends to increase as the rotational speed of the motor generator 10 increases (see FIG. 5). For this reason, for example, based on the rotational speed of the motor generator 10 calculated from the detection value of the rotation angle sensor 28, the range of the assumed fluctuation amount of the absolute value of the phase current used for the determination of the short circuit failure may be variably set. .

  If an affirmative determination is made in step S12, the process proceeds to step S14 to perform a short-circuit fault identification process.

  FIG. 6 shows a procedure of short-circuit fault identification processing according to the present embodiment. This process is executed by the control device 20.

  In this series of processing, in step S100, the determination currents Ijde for the U, V, and W phases are calculated based on the detection values of the current sensors 24 and 26. In the present embodiment, as shown in FIG. 7, U and W phase currents are sampled every 90 ° electrical angle of the motor generator 10, and each of the U and W phases is sampled in one cycle Tcr of current 4 The determination current Ijde is calculated as an average value of two phase currents (for example, phase currents sampled at times t1, t2, t3, and t4). That is, the determination current is an average value of a plurality of pairs of phase currents separated by a half cycle “Tcr / 2” of phase currents (a pair of phase currents at times t1 and t3 and a pair of phase currents at times t2 and t4). Ijde is calculated. The determination current Ijde calculated in this way approximates the direct current component Iave of the phase current indicated by the alternate long and short dash line in the figure.

  In FIG. 7, a substantially sinusoidal waveform (for example, a fundamental wave component of the phase current) is shown as the phase current waveform, but actually, the phase current includes a harmonic component in addition to the fundamental wave component. May also be included.

  Incidentally, in this embodiment, it is assumed that the sampling timings of the U and W phase currents are synchronized with each other. The determination current Ijde corresponding to the V phase may be calculated based on the V phase current iv calculated from the detected values of the U and V phase currents by the current sensors 24 and 26.

  Returning to the description of FIG. 6, in subsequent steps S <b> 102 to S <b> 108, it is specified which of the switching elements Sjp and Sjn included in the inverter IV has a short-circuit fault. Hereinafter, the specific principle of the switching element in which the short circuit failure has occurred will be described with reference to FIG.

  FIG. 8 is a diagram illustrating the relationship between the occurrence location of the short-circuit fault in the switching element and the DC component of the phase current. In the figure, the vertical axis represents the DC component of the phase current, and the horizontal axis represents time. In the drawing, as described above, the phase current flowing in the direction from the inverter IV to each phase coil of the motor generator 10 is defined as positive.

  As shown in the figure, the absolute value of the DC component of the phase current corresponding to the phase of the switching element in which the short circuit failure has occurred is larger than the absolute value of the DC component of the phase current corresponding to the remaining two phases. For example, when a short circuit failure occurs in the switching element Sup, the absolute value of the direct current component of the U-phase current iu becomes larger than the absolute value of the direct current components of the V and W phase currents iv and iw.

  In addition, the polarity of the DC component of the phase current corresponding to the phase of the switching element in which the short circuit failure has occurred is different from the polarity of the DC component of the phase current corresponding to the remaining two phases. For example, when a short circuit failure occurs in the switching element Sup, the polarity (positive) of the DC component of the U-phase current iu is different from the polarity (negative) of the DC component of the V, W-phase currents iv, iw.

  Using these points, it is possible to identify the switching element in which the short-circuit failure has occurred based on the absolute value and polarity of the determination current Ijde as the average value of the phase currents.

  Returning to FIG. 6, in step S102, the phase corresponding to the U, V, W phase determination current Ijde corresponding to the maximum absolute value is determined.

  In a succeeding step S104, it is determined whether or not the polarity of the determination current Ijde having the maximum absolute value is positive.

  If it is determined in step S104 that the polarity is positive, the process proceeds to step S106, where the absolute value of the determination current Ijde is the maximum, and a short circuit fault has occurred in the switching element on the high potential side. Specified.

  On the other hand, if it is determined in step S104 that the polarity is negative, the process proceeds to step S108, where the absolute value of the determination current Ijde is the maximum and the short-circuit fault occurs in the switching element Sjn on the low potential side. Identify that has occurred.

  In addition, when the process of step S106, S108 is completed, this series of processes is once complete | finished.

  Returning to the description of FIG. 4, a fail-safe process is performed in step S16. In the present embodiment, the three-phase short-circuit process is performed as a fail-safe process.

  By the way, the three-phase short-circuit process continues after the short-circuit fault location of the switching element is specified by the short-circuit fault specifying process until the inverter IV is repaired at the vehicle repair shop until the short-circuit fault of the switching element is resolved. Will be.

  When a negative determination is made in steps S10 and S12, or when the process of step S16 is completed, this series of processes is temporarily terminated.

  FIG. 9 shows an example of a short-circuit fault identification process according to the present embodiment. Specifically, FIG. 9A shows the transition of the phase current, and FIG. 9B shows the transition of the determination current Ijde. FIG. 9 shows changes in phase current and the like when the rotation speed of the motor generator 10 is constant.

  In the illustrated example, a short circuit protection process is performed when a short circuit failure of the switching element occurs at time t1. Thereafter, at time t2, the switching element in which the short-circuit fault has occurred is specified by the short-circuit fault specifying process, and the three-phase short-circuit process is started. In the example shown in FIG. 9, the period TA (time t1 to t2) from when the short-circuit failure of the switching element occurs until the three-phase short-circuit process is started is about two electrical angles.

  Here, FIG. 9 also shows the specific process of the switching element in which the short-circuit failure has occurred according to the conventional technique. In this case, the rotation speed of motor generator 10 is the same as the rotation speed described in the present invention.

  In the prior art, the determination current is calculated by applying a low-pass filter process to the phase current. In such calculation of the determination current, the timing at which the absolute value of the U-phase current iu, V-phase current iv, and W-phase current iw can be determined from the timing (time t1) when the short-circuit failure occurs in the switching element. The period up to (time t3) is longer than the period TA. In this case, the three-phase short-circuiting process cannot be started quickly, and the time during which a large current flows through each phase coil 10u, 10v, 10w becomes long, so that these three-phase short-circuiting processes are started before The coils 10u, 10v, and 10w may be disconnected.

  In order to avoid such a situation, for example, it is conceivable to reduce the time constant of the low-pass filter. However, if the time constant is reduced, the rotational speed region of the motor generator 10 that can identify the short-circuit fault location may be restricted, such as the DC component cannot be calculated from the phase current when the motor generator 10 rotates at a low speed. .

  In order to avoid the above situation, for example, the time constant of the low-pass filter may be variable according to the frequency of the phase current. However, in this case, there is a possibility that the number of matching man-hours at the time of designing the low-pass filter increases.

  As described above, in this embodiment, by performing the short-circuit fault specifying process of the above aspect, it is possible to avoid any restriction on the rotational speed region of the motor generator 10 that can specify the short-circuit fault location, It is possible to quickly identify whether a short-circuit failure has occurred.

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

  (1) The determination current Ijde was calculated as the average value of the four phase currents corresponding to the timing at which the electrical angle was separated by 90 ° in one phase Tcr of the phase current. Thereby, for example, compared with a method of calculating the direct current component of the phase current by a low-pass filter, an increase in the number of adaptation man-hours at the time of designing the control logic for calculating the determination current Ijde is suppressed, or the short-circuit fault location of the switching element is reduced. It can be avoided that the rotational speed region of the identifiable motor generator 10 is restricted.

  Then, based on the absolute value and polarity of the determination current Ijde calculated in the above mode, the switching element that caused the short-circuit failure was specified. Thereby, the switching element in which the short-circuit failure has occurred can be quickly identified, and as a result, the short-circuit failure can be promptly shifted to the three-phase short-circuit process.

  (2) The three-phase short-circuit process was continued after the short-circuit fault location of the switching element was specified by the short-circuit fault specifying process until the short-circuit fault of the switching element was resolved. Thereby, for example, it is possible to avoid disconnection of each phase coil 10u, 10v, 10w before the vehicle arrives at the repair shop.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In this embodiment, as shown in FIG. 10, the determination current Ijde is calculated as the total value S of the four phase currents sampled in one cycle Tcr of the phase current. The determination current Ijde thus calculated is a value proportional to the DC component Iave of the phase current.

  Note that the procedure of the short-circuit fault identification process based on the determination current Ijde calculated in the above manner is in accordance with the procedure shown in FIG.

  As described above, in this embodiment, the determination current Ijde is calculated as the total value S of the four phase currents sampled in one cycle Tcr of the phase current. By performing the short-circuit fault identification process based on the determination current Ijde thus calculated, it is possible to quickly identify which switching element has a short-circuit fault.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

In this embodiment, as shown in FIG. 11, the maximum value Imax and the minimum value Imin of the U and W phase currents are sampled in one cycle Tcr of the phase current, and the sampled phase currents are expressed as in the following equation (e1). The determination current Ijde is calculated as the median value of the maximum value Imax and the minimum value Imin.
Ijde = (Imax + Imin) / 2 (e1)
The phase current (for example, the fundamental wave component of the phase current) alternately becomes maximum and minimum every approximately half cycle “Tcr / 2”. For this reason, the determination current Ijde calculated in this way approximates to the DC component Iave of the phase current indicated by the one-dot chain line in the figure.

  In this embodiment, each of the U and W phase currents is sampled each time, and the maximum value and the minimum value are acquired from the sampled phase currents. Further, the maximum value and the minimum value of the V-phase current may be calculated based on the V-phase current calculated from the U and W phase currents.

  Thus, in the present embodiment, the determination current Ijde is calculated in the above manner. By performing the short-circuit fault identification process based on the determination current Ijde thus calculated, it is possible to quickly identify which switching element has a short-circuit fault.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the first embodiment, the short-circuit fault location of the switching elements Sjp and Sjn is specified based on both the absolute value and the polarity of the determination current Ijde corresponding to each phase. However, the present invention is not limited to this. For example, the short-circuit fault location of the switching element may be specified based on either the absolute value or polarity of the determination current Ijde corresponding to each phase. When the method for identifying a short-circuit fault location based on the absolute value is adopted, it is possible to specify whether a short-circuit fault has occurred in any of the pair of switching elements corresponding to which phase of the U, V, and W phases. .

  On the other hand, when the method for identifying the short-circuit fault location based on the polarity is adopted, it is possible to specify which one of the high-potential side switching element Sjp and the low-potential side switching element Sjn has the short-circuit fault. Note that the specific method based on polarity is, for example, the case where the phase current exceeds the detectable range of the current sensor, and the relationship between the polarity of the judgment current corresponding to each phase and the short-circuit fault location is shown in FIG. It can be used in situations where the indicated relationship is satisfied.

  -Fail-safe processing is not limited to three-phase short-circuit processing. For example, the rotational speed of the motor generator 10 may be reduced to reduce the induced voltage applied to each phase coil 10u, 10v, 10w. Specifically, for example, the power transmission mechanism interposed between the drive wheel 14 and the output shaft of the motor generator 10 is used to cut off the power between the drive wheel 14 and the output shaft of the motor generator 10. Good. Such a process may be employed, for example, when a short-circuit fault identification process based only on the absolute value of the determination current Ijde is employed. This is because it is impossible to specify which one of the high-potential side switching element Sjp and the low-potential side switching element Sjn has a short-circuit fault, and the three-phase short-circuit process cannot be performed.

  The calculation method of the determination current Ijde (DC component equivalent amount) is not limited to those exemplified in the above embodiments.

  For example, in the first embodiment, a phase current is sampled every electrical angle 180 ° instead of every electrical angle 90 °, and a pair of phase currents sampled in one electrical angle cycle (for example, the previous FIG. 7). A method of calculating the determination current Ijde as an average value of a pair of phase currents at times t1 and t3) may be employed. Such a method can also be applied to the calculation method of the determination current Ijde in the second embodiment.

  In the first and second embodiments, the sampling period of the phase current used for calculating the determination current Ijde is not limited to the electrical angles of 90 ° and 180 °, but may be other periods. Here, if a sampling period (for example, an electrical angle of 45 °) in which a period that is an integral multiple of the sampling period coincides with a half period of the phase current (an electrical angle of 180 °) is adopted, the above-described first embodiment is shown. As described above, the average value of the phase current approximates the direct current component of the phase current, and as shown in the second embodiment, the total value of the phase current is a value proportional to the direct current component of the phase current. On the other hand, even when a sampling period (for example, an electrical angle of 50 °) in which an integer multiple of the sampling period does not coincide with a half period of the phase current is employed, for example, the induced voltage applied to each phase coil is high. As long as the voltage of the battery 16 is not exceeded, it is possible to specify which of the high potential side switching element Sjp and the low potential side switching element Sjn has a short-circuit fault based on the polarity of the determination current Ijde.

  Further, for example, as shown in the first embodiment, instead of the method of calculating the determination current Ijde as the average value of the phase currents sampled in one electrical angle cycle, the electrical angle N cycle (N is 2 or more) A method of calculating the determination current Ijde as an average value of the phase currents sampled in (integer integer) may be employed. Specifically, for example, the determination current Ijde may be calculated as an average value of the pair of phase currents at the times t1, t3, t5, and t7 of FIG. However, when priority is given to quickly identifying a short-circuit fault in the switching element, it is desirable to calculate the determination current Ijde by the method described in the first embodiment.

  Furthermore, for example, a method of calculating the determination current Ijde as an average value of a plurality of sets of a pair of phase currents sampled at each of the electrical angular periods that are separated from each other may be employed. Specifically, for example, the determination current Ijde is an average value of the pair of phase currents at time t1 and t3 in FIG. 7, the pair of phase currents at times t9 and t11, and the pair of phase currents at times t1 and t7. May be calculated.

  The switching element included in the inverter IV is not limited to the IGBT but may be a MOSFET, for example.

  -Vehicles to which the present invention is applied are not limited to hybrid vehicles. For example, the vehicle may be an electric vehicle or a fuel cell vehicle that includes only a rotating machine as the in-vehicle main unit. The application object of the present invention is not limited to a vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Motor generator, 16 ... High voltage battery, 20 ... Control apparatus, 24, 26 ... Current sensor, IV ... Inverter, Sjp, Sjn ... Switching element, FDjp, FDjn ... Freewheel diode.

Claims (10)

In a control device for a multiphase rotating machine that controls a multiphase rotating machine by turning on and off a pair of high potential side switching elements and low potential side switching elements corresponding to each phase of the multiphase inverter,
Under the circumstances where all the high potential side switching elements and the low potential side switching elements included in the inverter are turned off, each phase current flowing between the inverter and the rotating machine is related to the electrical angle of the rotating machine. Calculation means for calculating a DC component equivalent amount based on a value at each of a plurality of attached timings;
Control of a multi-phase rotating machine, comprising: a short-circuit fault specifying means for specifying a short-circuit fault location of the switching element provided in the inverter based on the DC component equivalent amount of each phase calculated by the calculation means apparatus. The calculation means calculates an average value of values at each of the plurality of timings as the DC component equivalent amount,
2. The control device for a multi-phase rotating machine according to claim 1, wherein the short-circuit fault identification unit identifies a short-circuit fault location of the switching element based on the calculated average value of each phase. The calculation means calculates a total value of the values at each of the plurality of timings as the DC component equivalent amount,
2. The control device for a multi-phase rotating machine according to claim 1, wherein the short-circuit fault identification unit identifies a short-circuit fault location of the switching element based on the calculated total value of the respective phases.   The calculation means calculates the DC component equivalent amount for each phase current based on one set or a plurality of sets of a pair of values separated by a time interval obtained by multiplying a half cycle of the phase current by an odd number. Item 4. The control device for a multiphase rotating machine according to any one of Items 1 to 3. The calculation means calculates, for each phase current, the median value of the maximum value and the minimum value as the DC component equivalent amount based on one or more sets of the maximum value and the minimum value of the phase current,
2. The control device for a multi-phase rotating machine according to claim 1, wherein the short-circuit fault specifying unit specifies a short-circuit fault location of the switching element based on the calculated median value of each phase.   6. The multiphase rotating machine according to claim 1, wherein the calculation unit calculates the DC component equivalent amount based on the phase current within one cycle of the phase current. Control device.   The short-circuit fault specifying means specifies that a short-circuit fault has occurred in the switching element of the phase corresponding to the largest absolute value among the DC component equivalents of each phase. The control device for a multiphase rotating machine according to any one of claims 6 to 6.   The short-circuit fault specifying means specifies which of the high-potential side switching element and the low-potential side switching element has a short-circuit fault based on the polarity of the DC component equivalent amount of each phase. The control apparatus of the multiphase rotating machine of any one of Claims 1-7.   When it is specified by the short-circuit fault specifying means that a short-circuit fault has occurred, the short-circuit means for turning on all of the switching elements on the high-potential side and the low-potential side that have been specified that the short-circuit fault has occurred is further provided. The control device for a multi-phase rotating machine according to claim 8.   The multi-phase according to claim 9, wherein the short-circuit means continues the on-operation until the short-circuit fault is resolved after the short-circuit fault specifying means specifies that the short-circuit fault has occurred. Control device for rotating machine.

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