JP2005192324A - Device for detecting fault in power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a fault with high accuracy that occurs to a power supply system for a vehicle that has pre-charging function. <P>SOLUTION: A controller executes a program that includes a step, in which a battery current that flows from a battery to a smoothing capacitor is integrated (S200), while in pre-charging (YES in S100); a step in which it is decided whether a predetermined pre-charging time has elapsed (S300); and a step in which, when the predetermined pre-charging time elapses (YES in S300) and when the inverter voltage (VI), the voltage value of the smoothing capacitor, increases up to nearly the battery voltage (VB) (NO in S400), the fault portion of the power supply system is specified, based on the inverter voltage (VI) and the battery current integrated value (&Sigma;IB) (S500). <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a vehicle equipped with a traveling motor such as an electric vehicle, a fuel cell vehicle, and a hybrid vehicle, and more particularly to an apparatus for detecting an abnormality in a power supply system that connects and disconnects a battery and a load.

  A large-capacity electrolytic capacitor is provided between terminals on the input side of the inverter of the electric vehicle in order to smooth the voltage fluctuation and stabilize the operation of the inverter. When driving an electric vehicle, the capacitor is charged by closing the contactor (relay) by operating the main switch, but if the capacitor is charged directly by the main battery, a large current may flow and damage the contactor contact is there. Therefore, first, the precharge contactor is closed, the capacitor is precharged while limiting the current with a resistor or the like, and the contactor is prevented from being damaged by closing the main contactor after the precharge is completed. For this reason, it is important to reliably determine the end of precharge.

  Japanese Patent Laid-Open No. 10-304501 (Patent Document 1) discloses a control device for an electric vehicle that reliably determines the end of precharging of a capacitor provided in an inverter of the electric vehicle. This electric vehicle control device is provided between an inverter that drives a traveling motor by converting DC power of a main battery into AC power, a main contactor provided between the main battery and the inverter, and between the main battery and the inverter. A precharge contactor, a smoothing capacitor connected in parallel to the inverter, and a control circuit that closes the precharge contactor to precharge the capacitor and closes the main contactor when it is determined that the precharge is completed. A control device for an electric vehicle, comprising: a current detection circuit that detects a precharge current; and a determination circuit that determines that precharge has ended when a precharge current after a predetermined time from the start of precharge is equal to or less than a reference value. Including.

According to the control apparatus for an electric vehicle, the current detection circuit that detects the precharge current is provided, and the determination circuit finishes the precharge when the precharge current after a predetermined time from the start of the precharge is equal to or less than a reference value. Is determined. For this reason, it is possible not only to avoid an erroneous determination of the end of precharge during an abnormality in which the capacitor charge is discharged to the electric load during precharge, but also the voltage of the main battery drops and the precharge end voltage becomes the reference. Even when the value does not rise above the value, the end of precharge can be accurately determined.
JP-A-10-304501

  The determination circuit in the control apparatus for an electric vehicle disclosed in Patent Document 1 determines that precharge is completed when a precharge current after a predetermined time from the start of precharge is equal to or less than a reference value. It is possible to detect an abnormal time when the electric charge is discharged to the electric load. However, since the determination at the time of abnormality compares the instantaneous value of the precharge current with the reference value, it is difficult to determine the abnormality with high accuracy.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to detect an abnormality in a power supply system that can accurately detect an abnormality occurring in a power supply system for a vehicle having a precharge function. Is to provide a device.

  The abnormality detection apparatus for a power supply system according to a first aspect of the invention detects an abnormality in a power supply system in which the power of the power storage mechanism is supplied to the electric load via the power conversion circuit. The power supply system includes a first switch provided between the power storage mechanism and the power conversion device, and a second switch provided between the power storage mechanism and the power conversion device and provided in series with the resistor. And a smoothing capacitor connected in parallel to the power conversion circuit, and a control circuit that closes the second switch to precharge the smoothing capacitor and closes the first switch when the precharge is completed. This abnormality detection device is detected by voltage detection means for detecting the voltage value of the smoothing capacitor, current detection means for detecting the current value flowing from the power storage mechanism to the smoothing capacitor during precharging, and current detection means. Based on the integration means for integrating the measured current value, the voltage value at which the smoothing capacitor is to be charged by precharging, the detected voltage value of the smoothing capacitor, and the accumulated current value. Determination means for determining abnormality.

  According to the first invention, when the precharge time has elapsed, the voltage value of the smoothing capacitor connected in parallel to the power conversion device (for example, the inverter drive circuit) detected by the voltage detection means is smoothed by the precharge. If the capacitor has risen to a value almost close to the voltage value to be charged, it is determined that the capacitor has been precharged normally. During precharge, the current value flowing through a smoothing capacitor connected in parallel to the inverter circuit from a high voltage battery or the like as a power storage mechanism is detected and integrated. Despite the fact that this integrated value is higher than the appropriate upper limit value, the voltage value of the smoothing capacitor rises to a value almost close to the voltage value at which the smoothing capacitor should be charged by precharging when the precharge time has elapsed. Otherwise, the power from the high-voltage battery is not used for precharging the smoothing capacitor, but may have flowed to the electrical load, which is determined to be abnormal. Even if this integrated value is lower than the appropriate upper limit value and higher than the appropriate lower limit value, the voltage value of the smoothing capacitor is reduced by precharging when the precharge time elapses. If it has not increased to a value that is substantially close to the voltage value to be charged, it is determined that the voltage detection means for detecting the voltage value of the smoothing capacitor is abnormal. In this way, it is possible to determine the abnormality of the power supply system based on the integrated current value obtained by detecting and integrating the current value flowing through the smoothing capacitor. As a result, it is possible to provide an abnormality detection device for a power supply system that can accurately detect an abnormality occurring in a vehicle power supply system having a precharge function.

  The abnormality detection device for a power supply system according to a second aspect of the invention detects an abnormality in the power supply system in which the electric power of the power storage mechanism is supplied to the electric load via the power conversion circuit. The power supply system includes a first switch provided between the power storage mechanism and the power conversion device, and a second switch provided between the power storage mechanism and the power conversion device and provided in series with the resistor. And a smoothing capacitor connected in parallel to the power conversion circuit, and a control circuit that closes the second switch to precharge the smoothing capacitor and closes the first switch when the precharge is completed. The abnormality detection device includes a first voltage detection unit for detecting the voltage value of the power storage mechanism, a second voltage detection unit for detecting the voltage value of the smoothing capacitor, and the power storage mechanism during precharging. The current detection means for detecting the current value flowing through the smoothing capacitor, the integration means for integrating the current value detected by the current detection means, the voltage value of the power storage mechanism, and the voltage value of the smoothing capacitor are integrated. Determination means for determining an abnormality of the power supply system based on the current value.

  According to the second invention, when the precharge time has elapsed, the voltage value of the smoothing capacitor connected in parallel to the power conversion device (for example, the inverter drive circuit) detected by the second voltage detection means is When the voltage rises to a value that is substantially close to the voltage value of the high-voltage battery that is the power storage mechanism detected by the first voltage detection means, it is determined that the precharge is normally performed. During precharge, the current value flowing through a smoothing capacitor connected in parallel to the inverter circuit from a high voltage battery or the like as a power storage mechanism is detected and integrated. Even if this integrated value is higher than the appropriate upper limit value, if the voltage value of the smoothing capacitor does not rise to a value almost close to the voltage value of the high voltage battery when the precharge time has elapsed, the high voltage battery Is not used to precharge the smoothing capacitor and may have flowed into the electrical load, which is determined to be abnormal. Even if this integrated value is lower than the appropriate upper limit value and higher than the appropriate lower limit value, the voltage value of the smoothing capacitor becomes the voltage value of the high-voltage battery when the precharge time has elapsed. If it has not risen to a nearly close value, it is determined that the second voltage detecting means for detecting the voltage value of the smoothing capacitor is abnormal. In this way, it is possible to determine the abnormality of the power supply system based on the integrated current value obtained by detecting and integrating the current value flowing through the smoothing capacitor. As a result, it is possible to provide an abnormality detection device for a power supply system that can accurately detect an abnormality occurring in a vehicle power supply system having a precharge function.

  In the power supply system abnormality detection device according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the determining means includes means for determining an abnormal portion of the power supply system.

  According to the third invention, when the precharge time has elapsed, the voltage value of the smoothing capacitor has increased to a value that is approximately close to the voltage value at which the smoothing capacitor should be charged or the voltage value of the power storage mechanism. Otherwise, it is determined that there is an abnormality. If the voltage value of the smoothing capacitor is considerably low when the integrated current value is lower than the appropriate lower limit value and the precharge time has elapsed, the voltage detection means for detecting the voltage value of the smoothing capacitor is abnormal, or / And it is determined that the high-voltage power line is abnormal (disconnected). In this way, it is possible to determine an abnormal portion of the power supply system based on the integrated current value obtained by detecting and integrating the current value flowing through the smoothing capacitor.

  In the power system abnormality detection device according to the fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the determination means is a voltage detection means for detecting a power line abnormality of the power supply system and the voltage value of the smoothing capacitor. And a means for distinguishing and determining the abnormality of the electric load and the abnormality of the electric load.

  According to the fourth invention, when the precharge time has elapsed, it is determined that there is an abnormality if the voltage value of the smoothing capacitor has not increased to a value substantially close to the voltage value of the power storage mechanism. Furthermore, based on the voltage value of the smoothing capacitor, the voltage value of the power storage mechanism, and the current integrated value, the power supply line abnormality of the power supply system, the abnormality of the voltage detecting means for detecting the voltage value of the smoothing capacitor, and the abnormality of the electric load Can be determined and distinguished.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, the overall configuration of an abnormality detection system for a power supply system according to an embodiment of the present invention will be described.

  This power supply system abnormality detection system 1000 includes a battery 200, a smoothing capacitor 300 of an inverter, a load 500, relays 400, 410, and 420 for switching between connection and non-connection of the battery 200, a voltage of the battery 200 (the battery voltage VB). A voltage sensor 210 that detects a voltage of the capacitor 300 (this is referred to as an inverter voltage VI), and a controller 100 that controls them.

  The controller 100 controls the opening and closing of the relay 400 that directly connects the positive side of the battery 200 and the load 500, the function of controlling the opening and closing of the relay 420 that directly connects the negative side of the battery 200 and the load 500, A function of controlling opening and closing of a relay 410 connected in parallel to the relay 400 and connecting the battery 200 and the load 500 via the resistor 430 is provided. The load 500 is a drive motor, a drive circuit of an inverter that supplies power to the drive motor, or the like.

  The smoothing capacitor 300 functions to keep the output voltage of the battery 200 constant against load fluctuations and noise. If the relays 400 and 420 are suddenly closed at the time of startup, the contacts of the relays 400 and 420 may be welded due to the inrush current to the smoothing capacitor 300. Therefore, an operation called “precharge” is executed by the controller 100. That is, first, the relays 400, 410, and 420 are switched from the open state to the closed state, and the smoothing capacitor 300 is gradually charged (the current value is suppressed by the action of the resistor 430). After 300 is fully charged, relay 410 is switched to an open state and relay 400 is simultaneously switched to a closed state.

  When the battery voltage is VB, the capacitance value of the smoothing capacitor 300 is C, and the resistance value of the resistor 430 is R, the inverter voltage VI (t) after t seconds is VI (T) = VB · [1-exp {−t / (C · R)}].

  A table stored in the memory of the controller 100 will be described with reference to FIG. This table is a table for identifying an abnormal location.

  As shown in FIG. 2, in this table, the horizontal axis indicates the relationship between the integrated value (ΣIB) of the current flowing from the battery 200 to the smoothing capacitor 300, the appropriate lower limit value, and the appropriate upper limit value, and the vertical axis indicates The relationship between the inverter voltage of the smoothing capacitor 300 after precharging, the voltage threshold value A, and (battery voltage-voltage threshold value B) is shown.

  The voltage of the smoothing capacitor 300 (inverter voltage VI) measured by the voltage sensor 310 when the precharge is completed is higher than the voltage of the battery 200 (battery voltage VB−voltage threshold B) measured by the voltage sensor 210. If it is larger, it is determined that the precharge has ended normally. The voltage threshold B is a value set in advance based on the measurement accuracy of the voltage sensors 210 and 310, and is a small positive value.

  The voltage value (inverter voltage VI) of the smoothing capacitor 300 measured by the voltage sensor 310 after the precharge is smaller than the voltage threshold A, even though the integrated current value (ΣIB) is equal to or higher than the appropriate upper limit value, or When the voltage threshold A is equal to or higher than the value obtained by subtracting the voltage threshold B from the battery voltage, it is determined that an abnormality has occurred in the load 500. The abnormality of the load 500 is a case where the PN of the inverter drive circuit is short-circuited or a case where the load 500 is activated and power is consumed during precharging.

  When the integrated current value (ΣIB) is not less than the appropriate lower limit value and not more than the appropriate upper limit value, the voltage value of the smoothing capacitor 300 (inverter voltage VI) measured by the voltage sensor 310 after precharging is greater than the voltage threshold value A. When the voltage sensor 310 is smaller or equal to or greater than the voltage threshold A or less than the value obtained by subtracting the voltage threshold B from the battery voltage, it is determined that the voltage sensor 310 that measures the voltage value of the smoothing capacitor 300 is abnormal.

  When the integrated current value (ΣIB) is smaller than the appropriate lower limit value, and the voltage value (inverter voltage VI) of the smoothing capacitor 300 measured by the voltage sensor 310 after precharging is smaller than the voltage threshold A. Is determined that the high-voltage power line is disconnected or the voltage sensor 310 is abnormal. Further, in the case where the integrated current value (ΣIB) is smaller than the appropriate lower limit value, the voltage value (inverter voltage VI) of the smoothing capacitor 300 measured by the voltage sensor 310 after the precharge is equal to or higher than the voltage threshold value A. Is equal to or less than the value obtained by subtracting the voltage threshold B from the high-voltage power line disconnection and the voltage sensor 310 is determined to be abnormal.

  A control structure of a program executed by the controller 100 will be described with reference to FIG.

  In step (hereinafter, step is abbreviated as S) 100, controller 100 determines whether or not precharging is in progress. This determination is managed by a timer starting from the precharge start time, and it is determined that precharging is in progress until the timer expires. If precharging is in progress (YES in S100), the process proceeds to S200. Otherwise (NO in S100), this process ends.

  In S200, controller 100 integrates the battery current flowing from battery 200 to smoothing capacitor 300. This integrated current integrated value is ΣIB.

  In S300, controller 100 determines whether or not a predetermined precharge time has elapsed. If the precharge time determined in advance has elapsed (YES in S300), the process proceeds to S400. Otherwise (NO in S300), this process ends.

  In S400, controller 100 determines whether or not inverter voltage (VI) measured by voltage sensor 310 that measures the voltage of smoothing capacitor 300 has increased to near the voltage of battery 200 measured by voltage sensor 210. To do. If inverter voltage (VI) has risen to near battery voltage (VB) (YES in S400), this process ends. That is, it is determined that the precharge has been completed normally. If not (NO in S400), the process proceeds to S500.

  In S500, controller 100 identifies a failure location based on inverter voltage (VI) and battery current integrated value (ΣIB). At this time, the abnormality location identification table shown in FIG. 2 is used to determine whether the high-voltage power line disconnection, the inverter voltage sensor (voltage sensor 310) abnormality, or the load 500 abnormality. Thereby, a failure location is specified.

  An operation of the power system abnormality detection system according to the present embodiment based on the above-described structure and flowchart will be described.

  When the controller 100 receives a precharge start instruction, the relay 410 and the relay 420 are closed and precharge is started. Due to this precharging, a current flows from the battery 200 to the smoothing capacitor 300 via the resistor 430.

  Since precharging is in progress (YES in S100), the battery current is integrated and an integrated current value (ΣIB) is calculated (S200). When a predetermined precharge time has elapsed (YES in S300), the voltage value of battery 200 in which inverter voltage (VI), which is the voltage value of smoothing capacitor 300 measured by voltage sensor 310, is detected by voltage sensor 210. It is determined whether or not the battery voltage (VB) is increased (S400). If inverter voltage (VI) has risen to near battery voltage (VB) (YES at S400), it is determined that the precharge operation shown in FIG.

  If inverter voltage (VI) has not risen to near battery voltage (VB) (NO in S400), an abnormal location is specified using the abnormal location specification table shown in FIG. At this time, a voltage sensor that detects an abnormality of the load 500 and a voltage value of the smoothing capacitor 300 based on a combination of the current integrated value (ΣIB), the appropriate upper limit value and the appropriate lower limit value of the current integrated value, and the range of the inverter voltage. It is possible to identify one or two abnormal locations of the abnormality 310, the abnormality that the high-voltage power supply line is broken (S500).

  FIG. 4 shows a timing chart when the precharge ends normally. The inverter voltage (VI) increases with the start of precharge, and is close to the battery voltage (VB) at the end of precharge. On the other hand, FIG. 5 shows a timing chart when the load 500 is short-circuited. In this case, even if precharging is performed, the inverter voltage (VI) hardly increases, and there is a possibility that power is supplied from the battery 200 to the load 500 even during precharging. For this reason, it is determined that the load 500 is abnormal.

  As described above, according to the abnormality detection system for the power supply system according to the present embodiment, smoothing is performed after precharging using the integrated current value obtained by integrating the current value flowing from the battery to the smoothing capacitor during precharging. When the voltage value of the capacitor has not risen close to the battery voltage value, it is possible to identify an abnormal point in the power supply system.

  In the above-described embodiment, the case where the voltage sensor 210 that detects the voltage of the battery 200 (battery voltage VB) is used has been described. However, the present invention is not limited to the use of such a voltage sensor 210. Instead of the battery voltage VB, a voltage for charging the smoothing capacitor by precharging may be used. That is, when the precharge time has elapsed, whether or not the voltage value of the smoothing capacitor 300 has been normally precharged depends on whether or not the voltage value of the smoothing capacitor 300 has risen to a value approximately close to the voltage at which the smoothing capacitor 300 should be charged. It is determined whether or not, and an abnormal part is specified using the table of FIG. If it does in this way, the abnormal location in a power supply system can be specified, without using battery voltage VB.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall configuration diagram of an abnormality detection system for a power supply system according to an embodiment of the present invention. It is a figure which shows the abnormal location specific table memorize | stored in memory of a controller. It is a flowchart which shows the control structure of the program performed with a controller. It is a figure which shows the timing chart (the 1) in the abnormality detection system of the power supply system which concerns on embodiment of this invention. It is a figure which shows the timing chart (the 2) in the abnormality detection system of the power supply system which concerns on embodiment of this invention.

Explanation of symbols

  100 controller, 200 battery, 210, 310 voltage sensor, 300 smoothing capacitor, 400, 410, 420 relay, 430 resistor, 500 load, 1000 power supply system abnormality detection system.

Claims (4)

An abnormality detection device for a power supply system in which electric power of a power storage mechanism is supplied to an electric load via a power conversion circuit, wherein the power supply system is a first provided between the power storage mechanism and the power conversion device. A second switch provided between the power storage mechanism and the power converter, and provided in series with a resistor, and a smoothing capacitor connected in parallel to the power converter circuit, A control circuit that closes the second switch to precharge the smoothing capacitor and closes the first switch when the precharge ends,
The abnormality detection device is:
Voltage detection means for detecting the voltage value of the smoothing capacitor;
Current detection means for detecting a current value flowing from the power storage mechanism to the smoothing capacitor during the precharge;
Integrating means for integrating the current values detected by the current detecting means;
Determining means for determining an abnormality of the power supply system based on a voltage value at which the smoothing capacitor is to be charged by precharging, the detected voltage value of the smoothing capacitor, and the integrated current value; An abnormality detection device for a power system including An abnormality detection device for a power supply system in which electric power of a power storage mechanism is supplied to an electric load via a power conversion circuit, wherein the power supply system is a first provided between the power storage mechanism and the power conversion device. A second switch provided between the power storage mechanism and the power converter, and provided in series with a resistor, and a smoothing capacitor connected in parallel to the power converter circuit, A control circuit that closes the second switch to precharge the smoothing capacitor and closes the first switch when the precharge ends,
The abnormality detection device is:
First voltage detection means for detecting a voltage value of the power storage mechanism;
Second voltage detection means for detecting the voltage value of the smoothing capacitor;
Current detection means for detecting a current value flowing from the power storage mechanism to the smoothing capacitor during the precharge;
Integrating means for integrating the current values detected by the current detecting means;
An abnormality detection device for a power supply system, comprising: determination means for determining an abnormality of the power supply system based on a voltage value of the power storage mechanism, a voltage value of the smoothing capacitor, and the integrated current value.   The power supply system abnormality detection device according to claim 1, wherein the determination unit includes a unit for determining an abnormality location of the power system.   The determination means includes means for distinguishing and determining an abnormality of a power supply line of the power supply system, an abnormality of a voltage detection means for detecting a voltage value of the smoothing capacitor, and an abnormality of the electric load. An abnormality detection device for a power supply system described in 1.

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