JP2011217429A - Discharge control device of power conversion system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: it cannot be guaranteed that anomaly time discharge control, which causes a capacitor 16 to be discharged by turning on the high potential-side switching elements Swp and low potential-side switching elements Swn of an inverter IV to short-circuit both the electrodes of the capacitor 16, works when an anomaly actually occurs.SOLUTION: When a start switch is turned on, an anomaly discharge command dis1 is outputted and an operation of each high potential-side switching element Swp at anomaly discharge control is simulated. At this time, the gate voltage of the high potential-side switching element Swp is taken as a diagnostic signal dig1 into a control device 21 through a diagnostic interface 30. The control device 21 diagnoses the presence or absence of any anomaly in anomaly discharge control based on the diagnostic signal dig1.

Description

  The present invention relates to a power conversion circuit for converting the power of a DC power supply to a predetermined value, a capacitor interposed between the power conversion circuit and the DC power supply, and an electric path between the power conversion circuit, the capacitor and the DC power supply. Discharge that is applied to a power conversion system including an opening / closing means for opening and closing the capacitor, and that controls discharge of the charging voltage of the capacitor below a specified voltage by operating the power conversion circuit in a state where the opening / closing means is opened. The present invention relates to a discharge control device for a power conversion system including a control unit.

  As this type of discharge control device, for example, as shown in Patent Document 1 below, the switching element on the high potential side and the switching element on the low potential side of the inverter are simultaneously turned on, so that the input terminal of the inverter There has also been proposed one in which both electrodes of a connected capacitor are short-circuited to discharge the capacitor. In this control device, in order to avoid an excessive increase in current flowing when both electrodes of the capacitor are short-circuited, the voltage at the gate of the IGBT, which is a switching element, is reduced at the time of discharge control compared to the normal time. Yes.

JP 2009-232620 A

  By the way, when the switching element is operated in a mode different from the normal time at the time of discharge control as described above, the function of performing the discharge control is not used at the normal time. For this reason, being able to drive the inverter during normal time does not mean that the discharge control can be performed normally. For this reason, when a request to perform discharge control occurs, there is a possibility that the discharge control cannot actually be performed.

  The present invention has been made to solve the above-described problems, and its object is to operate a power conversion circuit to prevent abnormalities in discharge control by a discharge control means that controls discharge of a capacitor to a specified voltage or less. An object of the present invention is to provide a discharge control device for a power conversion system capable of appropriately diagnosing the presence or absence.

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

  According to a first aspect of the present invention, there is provided a power conversion circuit that includes a series connection body of a high-potential side switching element and a low-potential side switching element and that converts the power of a DC power source into a predetermined power, the power conversion circuit, and the DC The present invention is applied to a power conversion system including a capacitor interposed between power supplies, and an open / close means for opening and closing an electric path between the power conversion circuit and the capacitor and the DC power supply, and the open / close means is opened. The discharge voltage of the capacitor is discharged below a specified voltage by performing a process of shorting both electrodes of the capacitor by turning on both the high-potential side switching element and the low-potential side switching element. In a discharge control device of a power conversion system comprising a discharge control means for controlling, the switching element on the high potential side and the The potential-side switching element is a voltage-controlled switching element. The simulation means for simulating the operation of the switching element by the discharge control means, and the simulation process when the simulation process is performed by the simulation means An abnormality diagnosing means for diagnosing the presence or absence of abnormality in the discharge control by the discharge control means, using the applied voltage to the conduction control terminal of the switching element as an input, and the abnormality diagnosing means is input to the application Insulating means for outputting voltage while being insulated from the input side is provided, and the presence or absence of the abnormality is diagnosed based on an output signal of the insulating means.

  In the above invention, by providing the simulation means and the abnormality diagnosis means, it is possible to diagnose the presence or absence of abnormality in the discharge control without relying on detection of whether or not the capacitor is actually discharged. In addition, by using the output signal of the insulating means, it is possible to insulate the main body that determines whether there is an abnormality from the power conversion system.

  According to a second aspect of the present invention, in the first aspect of the present invention, a diagnostic switch for opening and closing an electrical path between the conduction control terminal and the abnormality diagnosis means is further provided.

  When a current flows from the continuity control terminal to the abnormality diagnosis means during the operation of the switching element, the charge / discharge speed of the continuity control terminal changes, which causes inconveniences such as a decrease in controllability of the switching speed of the switching state of the switching element. Cheap. In this regard, in the above invention, such a problem can be avoided by providing the diagnostic switch.

  According to a third aspect of the present invention, there is provided a power conversion circuit including a series connection body of a switching element on a high potential side and a switching element on a low potential side and converting power of a DC power source into a predetermined power, the power conversion circuit, and the DC The present invention is applied to a power conversion system including a capacitor interposed between power supplies, and an open / close means for opening and closing an electric path between the power conversion circuit and the capacitor and the DC power supply, and the open / close means is opened. The discharge voltage of the capacitor is discharged below a specified voltage by performing a process of shorting both electrodes of the capacitor by turning on both the high-potential side switching element and the low-potential side switching element. In a discharge control device of a power conversion system comprising a discharge control means for controlling, the switching element on the high potential side and the The potential-side switching element is a voltage-controlled switching element. The simulation means for simulating the operation of the switching element by the discharge control means, and the simulation process when the simulation process is performed by the simulation means An abnormality diagnosing means for diagnosing the presence or absence of abnormality in discharge control by the discharge control means, with an applied voltage to the conduction control terminal of the switching element to be an object, and between the conduction control terminal and the abnormality diagnosing means And a diagnostic switch for opening and closing an electrical path.

  In the above invention, by providing the simulation means and the abnormality diagnosis means, it is possible to diagnose the presence or absence of abnormality in the discharge control without relying on detection of whether or not the capacitor is actually discharged. By the way, when a current flows from the conduction control terminal to the abnormality diagnosing means when the switching element is operated, the charge / discharge speed of the conduction control terminal changes, so that the controllability of the switching speed of the switching state of the switching element is lowered. It is easy to produce. In this regard, in the above invention, such a problem can be avoided by providing the diagnostic switch.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the abnormality diagnosing means includes an insulating means for outputting the input applied voltage while being insulated from the input side, and an output signal of the insulating means. Based on the above, the presence or absence of the abnormality is diagnosed.

  In the said invention, the judgment body of the presence or absence of abnormality can be insulated from a power conversion system by using the output signal of an insulation means.

  According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the diagnostic switch includes a case where the discharge control is performed by the discharge control means and a case where the power conversion circuit is the original one. When used for the purpose, it is open.

  The invention according to claim 6 is the invention according to claim 5, further comprising a closing operation means for closing the diagnostic switch when a process to be simulated by the simulation means is performed.

  According to a seventh aspect of the invention, in the sixth aspect of the invention, when the discharge control drive circuit and the power conversion circuit used when the discharge control means operates the switching element are used for the original purpose. The normal-time drive circuit used for operating the switching element is different from the normal-time drive circuit, and the normal-time drive circuit receives an operation signal of the switching element to be driven via an insulating means. The closing operation means closes the diagnostic switch based on a signal that is different from that used for the original purpose being input to the normal driving circuit. Features.

  In the above invention, since the diagnostic switch can be closed based on the signal output from the insulating means used when inputting the operation signal to the normal driving circuit, the means side isolated from the power conversion system is Even when the closing operation command is output, it is not necessary to newly provide an insulating means.

  The invention according to claim 8 is the invention according to any one of claims 1, 2 and 4, wherein the insulating means is a transformer.

  The invention according to claim 9 is the invention according to any one of claims 1, 2 and 4, characterized in that the insulating means is a photocoupler.

  A tenth aspect of the present invention is the invention according to any one of the first to eighth aspects, wherein the abnormality diagnosis unit is configured to determine whether the abnormality is present based on a voltage value applied to a conduction control terminal of the switching element. It is characterized by diagnosing.

  According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the discharge control means is configured such that the current in at least one of the non-saturated region of the high potential side switching element and the low potential side switching element is the power conversion. The voltage applied to the conduction control terminal of the at least one switching element is set so as to be smaller than when the circuit is used for an original purpose, and the abnormality diagnosis means The presence or absence of the abnormality is diagnosed based on the value of the voltage applied to the conduction control terminal.

  In the above invention, since the voltage applied to the conduction control terminal during the discharge control is different from that used for the original purpose, the discharge control is ensured even when there is no abnormality in the use for the original purpose. There is no guarantee that it can be performed. In this regard, in the above-described invention, it is possible to confirm whether or not the operation at the time of discharge control can be realized by using the value of the voltage of the conduction control terminal when the at least one switching element is turned on by the simulated process. it can.

  The invention according to a twelfth aspect is the invention according to any one of the first to eleventh aspects, wherein the abnormality diagnosing unit is configured to determine whether the abnormality of the switching element is within a permissible range. It is characterized by diagnosing the presence or absence of.

  The on period in the discharge control period is set to a time interval such that the amount of heat generated by the switching element does not become excessively large. In the above invention, it is possible to confirm whether or not the operation according to this setting is performed.

  A thirteenth aspect of the invention is the invention according to any one of the first to twelfth aspects of the invention, wherein the abnormality diagnosing means is independent of the wiring between the conduction control terminal of the switching element and the drive circuit thereof. It is connected to the conduction control terminal through a wiring having the same potential as the conduction control terminal.

  When the potential of the wiring between the conduction control terminal of the switching element and its drive circuit is input as the potential of the conduction control terminal, this is detected even if the detection location of this potential and the wiring between the conduction control terminals are disconnected. It cannot be recognized. In the above invention, in view of this point, the voltage applied to the conduction control terminal is input using the other wiring.

  The invention according to a fourteenth aspect is the invention according to any one of the first to twelfth aspects, wherein the abnormality diagnosing means is configured such that the abnormality diagnosing means is connected via a wiring between a conduction control terminal of the switching element and a drive circuit thereof. The abnormality diagnosing means is connected to a conduction control terminal, and the abnormality diagnosing means is based on whether or not the power converter circuit is normally used for the original purpose in addition to the voltage applied to the conduction control terminal. The presence or absence of the abnormality is diagnosed.

  When a disconnection occurs on the conduction control terminal side of the wiring between the conduction control terminal and the drive circuit with respect to the connection point with the abnormality diagnosis means, a signal input as an applied voltage to the conduction control terminal is supplied to the abnormality diagnosis means Cannot recognize that. In the above invention, in view of this point, whether or not the disconnection abnormality is present can be diagnosed by considering whether or not the power converter circuit is normally used for the original purpose.

  A fifteenth aspect of the invention is the invention according to any one of the first to fourteenth aspects, further comprising a determination unit that determines whether or not an abnormality has occurred in a member on which the power conversion system is mounted. The control means is a process of short-circuiting both electrodes of the capacitor by turning on both the high-potential side switching element and the low-potential side switching element when the determination means determines that an abnormality has occurred. A normal discharge that discharges the capacitor without performing the short-circuiting process when the opening / closing means is in an open state and it is not determined that the abnormality has occurred. The apparatus further comprises means.

  Since the above abnormal discharge control means is not used in normal time, how to guarantee before the occurrence of abnormality whether the abnormal discharge control means actually operates when the determination means determines that an abnormality has occurred. It becomes a problem. In this regard, in the above-described invention, by setting the diagnosis target of the abnormality diagnosis unit to the abnormality discharge control unit, it is possible to guarantee the operation of the abnormality discharge control unit when a diagnosis of normality is made.

  The invention according to claim 16 is the invention according to claim 5, 7, 11 or 14, wherein the power conversion circuit includes a DC / AC conversion circuit that converts the power of the DC power source into AC and outputs the AC to the rotating machine. The original purpose of the power conversion circuit is to mediate transfer of power between the rotating machine and the DC power source in order to operate the rotating machine.

1 is a system configuration diagram according to a first embodiment. FIG. A circuit diagram showing composition of drive unit DU concerning the embodiment. The time chart which shows the discharge control at the time of abnormality concerning the embodiment. The time chart which shows the application method of the gate voltage at the time of abnormality concerning the embodiment. The flowchart which shows the process sequence of the normal time discharge control concerning the embodiment. The flowchart which shows the process sequence of the discharge control at the time of abnormality concerning the embodiment. The figure which shows the structure of the interface 30 for a diagnosis concerning the embodiment. The perspective view which shows the wiring layout concerning the embodiment. The flowchart which shows the procedure of the abnormality diagnosis process concerning the embodiment. The figure which shows the production | generation means of the diagnostic ON signal concerning 2nd Embodiment. The perspective view which shows the wiring layout concerning 3rd Embodiment. The flowchart which shows the procedure of the abnormality diagnosis process concerning the embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a discharge control device of a power conversion system according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows the system configuration of this embodiment. The illustrated motor generator 10 is an in-vehicle main machine and is mechanically coupled to drive wheels. Motor generator 10 is connected to high-voltage battery 12 via inverter IV and a parallel connection body of relay SMR2 and resistor 14 and relay SMR1. Here, the high voltage battery 12 has a terminal voltage of, for example, a high voltage of 100 V or higher. Further, among the input terminals of the inverter IV1, the capacitor 16 and the discharge resistor 18 are connected in parallel to the inverter IV side of the relays SMR1 and SMR2.

  The inverter IV is configured by connecting three series connection bodies of a high-potential side switching element Swp and a low-potential side switching element Swn as power elements in parallel. The connection points of the high-potential side switching element Swp and the low-potential side switching element Swn are connected to the respective phases of the motor generator 10.

  Between the input / output terminals (between the collector and the emitter) of the switching element Swp on the high potential side and the switching element Swn on the low potential side, the free wheel diode FDp on the high potential side and the free wheel diode FDn on the low potential side are connected. The cathode and anode are connected. The switching elements Swp and Swn are both formed of insulated gate bipolar transistors (IGBT). The switching elements Swp and Swn include a sense terminal St that outputs a minute current having a correlation with a current flowing between the input terminal and the output terminal.

  The minute current output from the sense terminal St flows through the shunt resistor 19, and the voltage drop due to this flows into the drive unit DU for driving the switching element Sw # (# = p, n). The drive unit DU forcibly turns off the switching element Sw # when it is determined that the current flowing between the input terminal and the output terminal of the switching element Sw # is equal to or greater than the threshold current Ith based on the voltage drop amount in the shunt resistor 19. It has a function to make a state.

  On the other hand, the control device 21 is an electronic control device that uses the low-voltage battery 20 as a power source. The control device 21 operates the inverter IV in order to control the control amount of the motor generator 10 as a control target. Specifically, the control device 21 operates based on operation values gup, gvp, gwp for operating the switching elements Swp for the U phase, the V phase, and the W phase of the inverter IV based on detection values of various sensors (not shown). Operation signals gun, gvn, and gwn for operating the switching element Swn are generated and output. Thereby, the switching elements Swp and Swn are operated by the control device 21 via the drive unit DU connected to their conduction control terminals (gates). In addition, the control device 21 detects a vehicle collision based on a detection value of an acceleration detection means (G sensor 22) that detects acceleration based on a force acting on the control device 21, and forcibly activates the capacitor 16 when a collision is detected. In order to perform the discharge process automatically, the abnormal-time discharge commands dis1 and dis2 are output to the respective drive units DU of the U-phase switching elements Swp and Swn.

  Incidentally, the high voltage system including the inverter IV and the low voltage system including the control device 21 are insulated by an insulating means such as a photocoupler (not shown), and the operation signal g * # (* = u, v, w , # = P, n) and the abnormal-time discharge commands dis1, 2 are output to the high voltage system via the insulating means. The operation signal g * p (* = u, v, w) and the operation signal g * n are complementary signals that are alternately turned on.

  FIG. 2 shows a configuration of a drive circuit unit that turns on / off switching element Sw # among drive units DU of switching element Sw #. Specifically, FIG. 2A shows the configuration of the V-phase and W-phase drive units DU, FIG. 2B shows the configuration of the U-phase lower arm drive unit DU, and FIG. The structure of the drive unit DU of the U-phase upper arm is shown.

  As shown in FIG. 2A, the V-phase and W-phase drive unit DU includes a power supply 40 having a terminal voltage VH, and the voltage of the power supply 40 is switched via the switching element 42 for charging and the gate resistor 44. Applied to the # conduction control terminal (gate). The gate of the switching element Sw # is connected to the output terminal (emitter) of the switching element via the gate resistor 44 and the discharge switching element 46, and this becomes a gate discharge path. The charging switching element 42 and the discharging switching element 46 are turned on and off by the normal-time drive control unit 48 according to the operation signal gj # (j = v, w). As a result, the switching element Sw # is turned on / off by the normal-time drive control unit 48.

  On the other hand, the drive unit DU of the lower arm of the U phase is basically the same as that shown in FIG. 2A as shown in FIG. A logical sum signal of the operation signal gun from the OR circuit 49 and the abnormal-time discharge command dis2 is input to the controller 48.

  Further, as shown in FIG. 2C, the drive unit DU of the U-phase upper arm turns on the switching element Swp in response to the abnormal-time discharge command dis1 in addition to the configuration shown in FIG. 2A.・ Equipped with a dedicated circuit for turning off. In this circuit, the voltage of the power supply 50 having a terminal voltage VL lower than the terminal voltage VH is applied to the gate of the switching element Swp via the charging switching element 52 and the gate resistor 44. The gate is connected to the emitter of the switching element Swp via the gate resistor 44 and the discharge switching element 54. Then, the charging switching element 52 and the discharging switching element 54 are turned on / off by the abnormal-time drive control unit 56 in accordance with the abnormal-time discharge command dis1. As a result, the switching element Swp is turned on / off according to the abnormal-time discharge command dis1. Here, in the drawing, a portion surrounded by a broken line is formed in a single integrated circuit 60. That is, the charging switching elements 42 and 52, the discharging switching elements 46 and 54, and the like are formed in the same integrated circuit.

  FIG. 3 shows a discharge control mode based on the abnormal-time discharge commands dis1,2. Specifically, FIG. 3A shows the transition of the state of the switching element Swp on the U-phase high potential side, and FIG. 3B shows the transition of the state of the switching element Swn on the low potential side of the U-phase. FIG. 3C shows the transition of the charging voltage of the capacitor 16. As illustrated, in the present embodiment, the switching element Swn on the high potential side is periodically switched between the on state and the off state while the switching element Swn on the low potential side of the U phase is maintained in the on state. As a result, there is a period in which both the high-potential side switching element Swp and the low-potential side switching element Swn are turned on at the same time. During this period, the two electrodes of the capacitor 16 are connected via the switching elements Swp and Swn. As a result, the capacitor 16 is discharged. Here, the one-time ON time of the switching element Swp is a parameter that determines the amount of heat generated by the switching elements Swp and Swn. For this reason, one ON time is set so that the temperature rise due to heat generation of the switching elements Swp and Swn does not become excessively large. The off time is a parameter that determines the rate of temperature rise of the switching elements Swp and Swn. For this reason, the one off time is set so that the temperature increase rate does not become excessively large.

  At this time, because of the configuration of the drive unit DU shown in FIG. 2, the gate applied voltage of the switching element Swp on the high potential side is higher than the gate applied voltage of the switching element Swn on the low potential side as shown in FIG. Lower. Here, FIG. 4A shows the transition of the abnormal-time discharge command dis1 with respect to the switching element Swp on the U-phase high potential side, and FIG. 4B shows the gate-emitter relationship between the switching element Swp on the high potential side. The transition of the voltage Vge is shown. FIG. 4C shows the transition of the abnormal discharge command dis2 for the U-phase low-potential side switching element Swn, and FIG. 4D shows the gate-emitter voltage of the low-potential side switching element Swn. The transition of Vge is shown.

  According to such a configuration, the switching element Swp on the high potential side is driven in the non-saturation region, and the switching element Swn on the low potential side is driven in the saturation region. This is because the gate application voltage of the low-potential side switching element Swn is lower than that of the high-potential side switching element Swp, so that the high-potential side switching element Swp is less saturated than the low-potential side switching element Swn. This is because the current becomes smaller. As a result, the current flowing through the switching element Swp on the high potential side and the switching element Swn on the low potential side by the discharge control is limited to the current in the non-saturated region of the switching element Swp on the high potential side. Also, the high-potential side switching element Swp and the low-potential side can be reduced by turning on / off the high-potential side switching element Swp a plurality of times to limit the on-time of the high-potential side switching element Swp. The current flowing through the switching element Swn can be limited. Note that it is desirable that the current in the non-saturation region of the switching element Swp on the high potential side is set to be less than the threshold current Ith defined by the drive unit DU. Incidentally, the terminal voltage VH is such that the threshold current Ith is in the saturation region. That is, when controlling the control amount of motor generator 10, switching elements Swp and Swn are driven in the saturation region.

  The discharge control is performed at the time of a vehicle collision or the like. In the present embodiment, the inverter IV is operated even when the vehicle is stopped during normal times and the relay SMR1 is switched to the open state. Discharge control is performed. However, the discharge control at this time is executed by passing a reactive current to the motor generator 10. Thereby, the capacitor 16 can be discharged more rapidly than the discharge of the capacitor 16 by the discharge resistor 18. Incidentally, the discharge resistor 18 is provided for an unexpected situation such as when the motor generator 10 is in a power generation state due to traction of the vehicle or the like and the capacitor 16 is charged.

  FIG. 5 shows a procedure for normal discharge control in the present embodiment. This process is repeatedly executed by the control device 21 at a predetermined cycle, for example.

  In this series of processes, first, in step S10, it is determined whether or not the relay SMR1 is switched from the closed state to the open state by turning off the start switch of the vehicle. Here, the vehicle activation switch is a means for allowing the user to activate the vehicle. The activation switch is not necessarily required to be mechanically operated. For example, even if the activation switch is a wireless device carried by the user and is close to the vehicle, the activation permission signal can be received by the vehicle side. Good. When an affirmative determination is made in step S10, in step S12, the operation signal g * # is set so as to flow a reactive current, and is output to each switching element Sw #. Here, for example, when the motor generator 10 is IPMSM or SPM, the operation signal g * # may be set so that the q-axis current is zero and the absolute value of the d-axis current is larger than zero.

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

  FIG. 6 shows a processing procedure of abnormal discharge control in the present embodiment. This process is repeatedly executed by the control device 21 at a predetermined cycle, for example.

  In this series of processes, first, in step S20, a detection value of the G sensor 22 is input. In a succeeding step S22, it is determined whether or not the vehicle has collided based on the input detection value. Here, if the detected acceleration is equal to or greater than a predetermined value, it may be determined that a collision has occurred. If it is determined that the vehicle has collided, the relays SMR1 and SMR2 are opened in step S24. Further, in step S26, the abnormal-time discharge commands dis1 and dis2 are output. When the process of step S26 is completed or when a negative determination is made in step S22, this series of processes is temporarily terminated.

  By the way, the abnormal discharge control is not used unless an abnormal situation such as a vehicle collision occurs. Whether or not the abnormal-time discharge control is surely performed in an abnormal state cannot be determined by whether or not the motor generator 10 can be normally controlled. This is because the abnormal-time discharge commands dis1 and 2 are signals different from the operation signals gup and gun, and the drive circuit used in the abnormal-time discharge control is when the control amount of the motor generator 10 is controlled. This is because of differences.

  Therefore, in the present embodiment, the diagnosis signals dig1 and dig2 captured through the diagnostic interface 30 shown in FIG. 1 are simulated by simulating the abnormal-time discharge control under the situation where the capacitor 16 is assumed to have no charge. Use it to see if the abnormal discharge control is actually feasible.

  FIG. 7 shows signals exchanged with the control device 21 when diagnosing whether there is an abnormality in the abnormal-time discharge control.

  As shown in the figure, a primary coil 32 a of a transformer 32 is connected between a gate and an emitter of a U-phase high-potential side switching element Swp via a diagnostic switching element 31. Here, the diagnostic switching element 31 is a normally open type switching element that is switched on by a diagnostic on signal sd1. This can be configured by, for example, a photo MOS relay or the like. One terminal of the secondary coil 32b of the transformer 32 is grounded, and the other terminal is connected to the control device 21 as a terminal for outputting the diagnostic signal dig1.

  The primary side (photodiode) of the photocoupler 34 is connected via the diagnostic switching element 33 between the gate and the emitter of the switching element Swn on the U-phase low potential side. Here, the diagnostic switching element 33 is a normally open type switching element that is switched to an ON state by a diagnostic ON signal sd2. This can be configured by, for example, a photo MOS relay or the like. One terminal of the secondary side (phototransistor) of the photocoupler 34 is grounded, and the other terminal is pulled up by the power source 35 via the resistor 36 and controlled as a terminal that outputs the diagnostic signal dig2. It is connected to the device 21.

  FIG. 8 shows a wiring layout between the gate of the switching element Swp on the high-potential side of the U phase (indicated in the figure that it is housed in the power card PC together with the freewheel diode FDp) and the transformer 32. As shown in the figure, the gate is connected to the diagnostic switching element 31 and the transformer 32 via a wiring 62, and this wiring 62 is a part further extending the path to connect the integrated circuit 60 and the gate. The gate and the diagnostic switching element 31 are connected. As a result, when a disconnection occurs between the integrated circuit 60 and the gate in the wiring 62, it can be surely recognized based on the input signal of the transformer 32. Note that the wiring layout between the gate of the switching element Swn on the low potential side of the U phase and the photocoupler 34 is also performed in the manner shown in FIG.

  FIG. 9 shows a procedure of abnormality diagnosis processing according to the present embodiment. This process is repeatedly executed by the control device 21 at a predetermined cycle, for example.

  In this series of processing, it is first determined in step S30 whether or not the start switch has been turned on. This process is for determining whether or not the diagnosis execution condition is satisfied. The start switch is the same as that described in step S10 of FIG. If it is determined that the start switch has been turned on, in step S32, an abnormal discharge command dis1 and a diagnostic on signal sd1 are output. In step S34, based on the diagnostic signal dig1, the voltage applied to the gate of the switching element Swp on the U-phase high potential side is within an allowable range (the difference from the terminal voltage VL is equal to or less than the threshold Δth), It is determined whether or not the logical product of the ON operation command period (pulse width) being within the allowable range is true. This process is for diagnosing whether or not the operation according to the abnormal-time discharge command dis1 is normally performed. If the logical product is diagnosed as true, the process proceeds to step S36.

  In step S36, an abnormal discharge command dis2 and a diagnostic on signal sd2 are output. In step S38, based on the diagnostic signal dig2, it is determined whether or not a voltage for an ON operation command is applied to the gate of the switching element Swn on the U-phase low potential side. Here, in this embodiment, since the diagnostic signal dig2 is an output signal of the photocoupler 34 as shown in FIG. 7, it cannot be confirmed whether or not the voltage value is in the normal range. This is because the signals that can be propagated by the photocoupler 34 are binary signals of logic “H” and logic “L”. However, even in this case, since the logic of the diagnostic signal dig2 is inverted by applying the voltage for the ON operation command to the gate, it is confirmed whether the voltage for the ON operation command is applied. I can.

  When it is diagnosed in step S38 that the voltage for the on operation command has been applied, in step S40, the relay SMR2 is closed to charge the capacitor 16 with the charge of the high voltage battery 12 through the high resistance electrical path. To do. When the predetermined time has elapsed (step S42: YES), in step S44, the relay SMR2 is switched to the open state and the relay SMR1 is switched to the closed state. As a result, the high voltage battery 12 and the capacitor 16 are connected by the low resistance electric path. It is assumed that the capacitor 16 is charged to a charging voltage that is assumed to prevent an excessively large current from flowing through the capacitor 16 even if the high voltage battery 12 and the capacitor 16 are connected by a low resistance electric path during the predetermined time. Set to

  On the other hand, if a negative determination is made in steps S34 and S38, in step S46, the user is notified of the presence of an abnormality and is recognized by the user. In addition, when the process of said step S44, S46 is completed, or when negative determination is made in step S30, this series of processes is once complete | finished.

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

  (1) Insulation means (transformer 32, photocoupler 34) for inputting and outputting the voltage applied to the gates of the U-phase switching elements Swp and Swn, and providing diagnostic signals dig1 and dig2 on the output side of the insulation means Based on this, the presence or absence of abnormality was diagnosed. Thereby, the presence or absence of abnormality can be diagnosed on the low voltage system side.

  (2) The diagnostic switching elements 31 and 33 for opening and closing the electrical path between the gates of the U-phase switching elements Swp and Swn and the insulating means are provided. As a result, it is possible to avoid a current from flowing from the drive unit DU or the gate side to the insulating means side except at the time of diagnosis, and in turn, it is possible to avoid a decrease in controllability of the charge / discharge rate of the gate.

  (3) The diagnostic switching elements 31 and 33 are of a normally open type. Thereby, the electrical path for diagnosis can be opened without power consumption except during diagnosis.

  (4) The voltage applied to the gate is set so that the current in the non-saturation region of the switching element Swp on the high potential side is smaller than when the inverter IV is used for its original purpose. In this case, even if no abnormality has occurred during use for the original purpose, it is not guaranteed whether the discharge control can be executed reliably, so the utility value of the abnormality diagnosis is particularly great.

  (5) The presence or absence of abnormality was diagnosed based on whether or not the length of the ON period of the switching element Swp on the high potential side was within an allowable range. Thereby, it can be confirmed whether the ON operation period is performed at an appropriate time interval in which the heat generation amount of the switching element Swp does not become excessively large.

  (6) The wiring that connects the transformer 32 and the photocoupler 34 and the gates of the switching elements Swp and Swn is a wiring that has the same potential as the gate, in addition to the wiring between the drive unit DU and the gate. Thereby, the disconnection of the wiring between the drive unit DU and the gate can be reliably detected by the diagnostic signals dig1 and dig2.

  (7) The processing for short-circuiting both electrodes of the capacitor 16 by turning on both the high-potential side switching element Swp and the low-potential side switching element Swn is performed only in an abnormal state. The capacitor 16 was discharged. In this case, the problem of how to ensure that the abnormal-time discharge control actually operates before the occurrence of an abnormality becomes a problem, and thus the utility value of the abnormality diagnosis is particularly great.

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

  FIG. 10 shows a propagation path of the diagnostic on signal sd1 according to the present embodiment. In FIG. 10, members corresponding to those shown in FIG. 6 are given the same reference numerals for convenience.

  As shown in the drawing, in this embodiment, a signal that propagates through the electrical path for inputting the operation signal “gup” is input to the normal-time drive control unit 48 in the drive unit DU to generate the diagnostic on signal sd1, and the diagnostic switching element 31 is provided with a closing operation circuit 70 that outputs to 31. The closing operation circuit 70 does not turn on the diagnostic switching element 31 when the operation signal “gup” input to the normal-time drive control unit 48 is input. On the other hand, the diagnostic switching element 31 is turned on using a signal that cannot be assumed as the operation signal “gup” as a trigger. This can be realized, for example, by configuring the closed operation circuit 70 with a low-pass filter that transmits a frequency lower than the switching frequency of the operation signal gup.

  Thereby, it is not necessary to configure the diagnostic switching element 31 with an insulating element. For this reason, the number of insulation means required for the power conversion system can be reduced. Note that the closed operation circuit of the diagnostic switching element 33 connected to the switching element Swn on the low potential side can be configured in the same manner, and therefore the description thereof is omitted here.

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

  FIG. 11 shows a wiring layout between the integrated circuit 60 and the transformer 32 according to the present embodiment. In FIG. 11, members corresponding to those shown in FIG. 8 are given the same reference numerals for convenience.

  As shown in the figure, in this embodiment, a portion of the wiring 62 that connects the integrated circuit 60 and the gate is connected to the transformer 32. For this reason, it is not possible to diagnose the presence or absence of an abnormality that causes a disconnection between the portion and the gate only by the input signal of the transformer 32. Therefore, in this embodiment, abnormality diagnosis processing is performed as shown in FIG.

  FIG. 12 shows a procedure of abnormality diagnosis processing according to the present embodiment. This process is repeatedly executed by the control device 21 at a predetermined cycle, for example. In FIG. 12, the same steps as those shown in FIG. 9 are given the same step numbers for the sake of convenience.

  In this series of processing, after the abnormality diagnosis processing (step S50) similar to that of the first embodiment is executed by turning on the start switch, the diagnostic signals dig1 and dig2 have no abnormality in step S52. It is determined whether the logical product of this and the previous inverter IV operation at the time of control of the control amount of the motor generator 10 is true. This condition is for diagnosing that the condition is normal. That is, when the disconnection occurs, the operation of the inverter IV does not become normal, and this is added as a condition.

(Other embodiments)
Each of the above embodiments may be modified as follows.
<About abnormality diagnosis means>
As abnormality diagnosis means, it is determined whether or not the voltage value and pulse width of the gate of the high-potential side switching element Swp are normal, and confirmation of application of the voltage for turning on the gate of the low-potential side switching element Swn is confirmed. It is not restricted to what performs. For example, it may be determined whether or not the gate voltage is normal for the switching element Swn on the low potential side. For example, both the high-potential-side switching element Swp and the low-potential-side switching element Swn may confirm only the application of the on-operation command voltage.

Moreover, it is not restricted to what is provided with an insulation means. Even if this is not provided, it is effective to provide a diagnostic switch as long as current can flow from the gate to the abnormality diagnosis means side.
<About diagnostic switches>
The present invention is not limited to the one provided with a diagnostic switch (diagnostic switching elements 31, 33). Even if this is not provided, the switching speed of the switching state of the switching elements Swp and Swn is adjusted by setting the resistance value of the gate resistor 44 in consideration of the current flowing through the transformer 32 and the photocoupler 34, for example. be able to.
<About closing operation means>
The closing operation means for closing the diagnostic switch is not limited to those exemplified in the above embodiments. For example, it is assumed that the abnormal discharge commands dis1 and dis2 are output via different signal lines for discharge control and abnormality diagnosis, and the abnormal discharge commands dis1 and dis2 are output via the diagnostic signal lines. It is good also as a means to perform closing operation by inputting as a trigger.
<About judgment means>
As a determination means for determining whether or not an abnormality has occurred in a member on which the power conversion system is mounted, a control device 21 that is mounted in the low voltage system and generates the operation signals gup, gun, gvp, gvn, gwp, gwn. Not limited to. For example, a dedicated unit that is mounted in the high-voltage system and generates the abnormal-time discharge commands dis1, 2 may be used. However, even in this case, it is desirable that the control device 21 can also output the abnormal-time discharge commands dis1 and 2 for diagnosis. This can be realized, for example, by setting the input signal of the drive unit DU as the logical sum of the signal of the dedicated means and the signal from the control device 21. However, even if the control device 21 does not have a function of generating the abnormal discharge commands dis1 and 2, the diagnosis is executed if the abnormal discharge commands dis1 and 2 are output by operating the dedicated means. can do.

Further, the determination means is not limited to determining that an abnormality has occurred based on the detection value of the G sensor 22. For example, it may be based on a diagnosis result of a diagnosis means for determining whether there is an abnormality in a power conversion system including a motor generator, an inverter IV, a boost converter CV, and the like.
<About drive unit DU>
The drive unit DU for the U-phase upper arm is not limited to one provided with the charging switching element 42 and the discharging switching element 46 in the normal state, and the charging switching element 52 and the discharging switching element 54 in the abnormal state. . For example, instead of sharing them, the means for applying a voltage to the input terminal of the charging switching element may be different between the normal time and the abnormal time.
<Regarding normal discharge means>
The normal-time discharging means is not limited to the one that causes the reactive current to flow through the motor generator 10. For example, a means for discharging the capacitor 16 by the discharge resistor 18 may be used. Further, for example, a means for operating a relay by providing a discharge circuit including a relay and a resistor between a positive input terminal and a negative input terminal of the inverter IV may be used.

Further, the means for performing the abnormal discharge control in each of the above embodiments may be a normal discharge means.
<Regarding discharge control means during abnormal conditions>
As an abnormal-time discharge control means, the short-circuit state of both electrodes of the capacitor 16 is obtained by repeating the ON state and the OFF state of the high-potential side switching element Swp a plurality of times while keeping the low-potential side switching element Swn in the on state. Is not limited to performing the process of generating a plurality of times. For example, a process of generating the short-circuit state of both electrodes of the capacitor 16 a plurality of times by repeating the on-state and the off-state of the low-potential side switching device Swn a plurality of times while keeping the high-potential side switching device Swp in an on state. It may be what performs. However, even in this case, it is desirable to set the gate applied voltage on the side where the on state and the off state are repeated a plurality of times to be lower and operate in the non-saturated region. Further, for example, a process of generating a short-circuit state of both electrodes of the capacitor 16 a plurality of times by repeating a simultaneous on state and a simultaneous off state of the high potential side switching element Swp and the low potential side switching element Swn a plurality of times. It may be what you do. Here, the gate applied voltage may be adjusted so that at least one of the high-potential side switching element Swp and the low-potential side switching element Swn is operated in the non-saturation region, but both are operated in the saturation region. May be. Further, both the high-potential side switching element Swp and the low-potential side switching element Swn may be turned on only once in the discharge control period.

  Further, the discharge control is not limited to using only the combination of the switching element Swp on the high potential side and the switching element Swn on the low potential side that applies a voltage to one phase of the motor generator 10. For example, the switching element Swp on the high potential side and the switching element Swn on the low potential side in all phases may be turned on simultaneously. Further, for example, the switching element Swp on the high potential side and the switching element Swn on the low potential side of each phase may be switched so as to be sequentially turned on.

Furthermore, the high-potential-side switching element Swp and the low-potential-side switching element Swn are turned on at the same time, so that the two electrodes of the capacitor 16 are not short-circuited. For example, a means for causing a reactive current to flow through the motor generator 10 may be used. In this case, for example, the normal-time discharging means may be a means for discharging by the discharge resistor 18.
<About DC / AC converter circuit>
As a DC / AC converter circuit (inverter IV) in which both the high-potential side switching element and the low-potential side switching element are turned on during the discharge control, the circuit between the rotating machine as the in-vehicle main unit and the high-voltage battery 12 is used. It is not limited to mediating power transfer. For example, the transfer of electric power between the high voltage battery 12 and a rotary machine other than the main machine such as a rotary machine provided in the air conditioner may be used.
<About power conversion circuit>
The power conversion circuit is not limited to the one composed only of the inverter IV. For example, a boost converter including a reactor, a switching element connected in parallel to the capacitor 16 via the reactor, a free wheel diode, and a capacitor connected to a series connection body of the switching element and the free wheel diode is connected to an inverter IV. May be connected to the input terminal. In this case, the capacitor connected to the output terminal of the boost converter and the capacitor 16 are subject to discharge control, and the voltage of the capacitor 16 is discharged through the freewheel diode as the voltage of the capacitor of the boost converter decreases. The Rukoto.

If a switching element is connected in parallel to the freewheel diode, the discharge control can be performed by turning on both of the pair of switching elements of the boost converter CV.
<Other>
In each of the embodiments described above, once the voltage drop amount of the shunt resistor 19 is latched once in one discharge control period, it is fixed. However, the present invention is not limited to this. It is desirable that the latch holds the maximum value of the voltage drop amount of the shunt resistor 19 and updates the hold value at each maximum point.

  The high-potential side switching element Swp and the low-potential side switching element Swn used for discharge control are not limited to IGBTs, and may be field effect transistors such as power MOS field effect transistors.

  The vehicle is not limited to a hybrid vehicle, and may be, for example, an electric vehicle in which the energy resource stored for the in-vehicle main engine is only electric energy.

  -As a discharge control apparatus, not only what is mounted in a vehicle, For example, you may apply to the power conversion system which converts the electric power of the direct-current power source provided in a house into alternating current. In this case, the abnormal time may be a case where, for example, an earthquake is detected.

  DESCRIPTION OF SYMBOLS 10 ... Motor generator, 12 ... High voltage battery (one embodiment of DC power supply), 16 ... Capacitor, 21 ... Control device, 30 ... Diagnostic interface, Swp ... High potential side switching element, Swn ... Low potential side switching Element Swn.

Claims (16)

A power conversion circuit comprising a series connection body of a switching element on the high potential side and a switching element on the low potential side and converting the power of the DC power supply to a predetermined value; a capacitor interposed between the power conversion circuit and the DC power supply; Applied to a power conversion system comprising an opening / closing means for opening / closing an electric path between the power conversion circuit and the capacitor and the DC power source, and switching on the high potential side under a situation where the opening / closing means is opened. Electric power provided with a discharge control means for controlling the discharge voltage of the capacitor to a specified voltage or less by performing a process of short-circuiting both electrodes of the capacitor by turning on both the element and the switching element on the low potential side In the discharge control device of the conversion system,
The high-potential side switching element and the low-potential side switching element are voltage-controlled switching elements,
Simulation means for simulating the operation of the switching element by the discharge control means;
An abnormality for diagnosing whether or not there is an abnormality in the discharge control by the discharge control means, using the voltage applied to the conduction control terminal of the switching element to be simulated when the process simulated by the simulation means is performed Diagnostic means,
The abnormality diagnosing means includes an insulating means for outputting the input applied voltage while being insulated from the input side, and diagnoses the presence or absence of the abnormality based on an output signal of the insulating means System discharge control device.   The discharge control device for a power conversion system according to claim 1, further comprising a diagnostic switch for opening and closing an electrical path between the conduction control terminal and the abnormality diagnosis means. A power conversion circuit comprising a series connection body of a switching element on the high potential side and a switching element on the low potential side and converting the power of the DC power supply to a predetermined value; a capacitor interposed between the power conversion circuit and the DC power supply; Applied to a power conversion system comprising an opening / closing means for opening / closing an electric path between the power conversion circuit and the capacitor and the DC power source, and switching on the high potential side under a situation where the opening / closing means is opened. Electric power provided with a discharge control means for controlling the discharge voltage of the capacitor to a specified voltage or less by performing a process of short-circuiting both electrodes of the capacitor by turning on both the element and the switching element on the low potential side In the discharge control device of the conversion system,
The high-potential side switching element and the low-potential side switching element are voltage-controlled switching elements,
Simulation means for simulating the operation of the switching element by the discharge control means;
An abnormality for diagnosing whether or not there is an abnormality in the discharge control by the discharge control means, using the voltage applied to the conduction control terminal of the switching element to be simulated when the process simulated by the simulation means is performed Diagnostic means;
A discharge control device for a power conversion system, comprising: a diagnostic switch that opens and closes an electrical path between the conduction control terminal and the abnormality diagnosis means.   The abnormality diagnosis unit includes an insulation unit that outputs the input applied voltage while being insulated from the input side, and diagnoses the presence or absence of the abnormality based on an output signal of the insulation unit. 4. A discharge control device for a power conversion system according to 3.   The diagnostic switch is opened when discharge control is performed by the discharge control means and when the power conversion circuit is used for an original purpose. The discharge control apparatus of the power conversion system of any one of 2-4.   6. The discharge control device for a power conversion system according to claim 5, further comprising a closing operation means for closing the diagnostic switch when the simulation process is performed by the simulation means. A discharge control driving circuit used when the discharge control means operates the switching element and a normal driving circuit used for operating the switching element when the power conversion circuit is used for its original purpose Are different from each other,
The normal-time drive circuit is one in which an operation signal of a switching element to be driven is input via an insulating means,
The said closing operation means closes the said diagnostic switch based on the signal different from the time of being used for the said original purpose being input into the said normal time drive circuit. 6. A discharge control device for a power conversion system according to 6.   The discharge control device for a power conversion system according to any one of claims 1, 2, and 4, wherein the insulating means is a transformer.   The discharge control device for a power conversion system according to any one of claims 1, 2, and 4, wherein the insulating means is a photocoupler.   The power conversion system according to any one of claims 1 to 8, wherein the abnormality diagnosis unit diagnoses the presence or absence of the abnormality based on a value of a voltage applied to a conduction control terminal of the switching element. Discharge control device. The discharge control means is configured so that the current in at least one of the non-saturated region of the high-potential side switching element and the low-potential side switching element is smaller than when the power conversion circuit is used for its original purpose. Setting a voltage to be applied to the conduction control terminal of the at least one switching element;
The discharge control device for a power conversion system according to claim 10, wherein the abnormality diagnosis means diagnoses the presence or absence of the abnormality based on a value of a voltage applied to a conduction control terminal of the at least one switching element.   12. The power according to claim 1, wherein the abnormality diagnosis unit diagnoses the presence or absence of the abnormality based on whether or not a length of an ON period of the switching element is within an allowable range. Discharge control device for conversion system.   The abnormality diagnosing means is connected to the conduction control terminal via a wiring having the same potential as the conduction control terminal separately from the wiring between the conduction control terminal of the switching element and a drive circuit thereof. The discharge control device for a power conversion system according to any one of claims 1 to 12. The abnormality diagnosis means is connected to the conduction control terminal via a wiring between the conduction control terminal of the switching element and a drive circuit thereof,
The abnormality diagnosing means diagnoses the presence or absence of the abnormality based on whether or not the power conversion circuit is normally used for an original purpose in addition to the voltage applied to the conduction control terminal. The discharge control device for a power conversion system according to any one of claims 1 to 12. A determination means for determining whether or not an abnormality has occurred in a member on which the power conversion system is mounted;
The discharge control unit short-circuits both electrodes of the capacitor by turning on both the high-potential side switching element and the low-potential side switching element when the determination unit determines that an abnormality has occurred. An abnormal discharge control means for performing the process of
A normal-time discharging unit that discharges the capacitor without performing the short-circuiting process when the opening / closing unit is in an open state and it is not determined that the abnormality has occurred. Item 15. The discharge control device for a power conversion system according to any one of Items 1 to 14. The power conversion circuit includes a direct current alternating current conversion circuit that converts electric power of the direct current power source into alternating current and outputs the alternating current to a rotating machine,
The original purpose of the power conversion circuit is to mediate transfer of electric power between the rotating machine and the DC power supply in order to operate the rotating machine. The discharge control device for a power conversion system according to 11 or 14.

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