JP2013162638A - Power control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that there is no means to cope with the case that disconnection is generated in a total voltage detection line Ld for detecting the voltage (Total voltage Vb) between both electrodes of a high-voltage battery 10 and a relay driving signal line Ll for energizing relays SMRa, SMRb, SMRc.SOLUTION: The total voltage detection line Ld is connected between a power conversion circuit 14 and the relays SMRa, SMRb, SMRc. When it is determined that a total voltage Vb is a specified voltage or lower during closed-operation of the relays SMRa, SMRc, it is diagnosed that disconnection is generated in the total voltage detection line Ld, and the relay driving signal line Ll and open-operation of the relays SMRa, SMRc is performed.

Description

  The present invention provides an opening / closing means for opening / closing between a power storage device and a power conversion circuit, an opening / closing operation means for opening / closing the opening / closing means, and a terminal voltage of the power storage device connected between the opening / closing means and the power conversion circuit. The present invention relates to a power supply control device including terminal voltage detection means for detecting.

  As a power storage device, for example, a device including a series connection body of a plurality of capacitor cells has been proposed as seen in Patent Document 1 below. Here, it has also been proposed to provide a voltage detection line for detecting the voltage of each capacitor cell and detect disconnection of these voltage detection lines.

JP 2004-180395 A

  By the way, when connecting a power storage device and a power conversion circuit, it is well known to provide a relay between the power storage device and the power conversion circuit. In addition, even if the power storage device is a series connection body of a plurality of cells and includes means for individually detecting the voltage of each cell, wiring for detecting the terminal voltage of the power storage device is provided on both electrodes of the power storage device. May be connected. Under such circumstances, it is impossible to ignore the possibility of disconnection of the signal line for driving the relay and the wiring for detecting the terminal voltage of the power storage device.

  The present invention has been made in the process of solving the above-mentioned problems, and its object is to open / close means for opening / closing between a power storage device and a power conversion circuit, opening / closing operation means for opening / closing the opening / closing means, and the opening / closing means. Another object of the present invention is to provide a new power supply control device including terminal voltage detection means connected between the power conversion circuits and detecting a terminal voltage of the power storage device.

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

  The invention according to claim 1 includes an opening / closing means (SMRa, SMRb, SMRc) for opening / closing between the power storage device (10) and the power conversion circuit (14), an opening / closing operation means (50) for opening / closing the opening / closing means, The terminal voltage detection means (40, 42, 44) connected between the opening / closing means and the power conversion circuit for detecting the terminal voltage of the power storage device, and the opening / closing means being closed by the opening / closing operation means And an abnormality diagnosing means (50) for diagnosing that an abnormality has occurred in either the opening / closing means or the terminal voltage detecting means based on the detection value of the terminal voltage detecting means being out of a predetermined range. It is characterized by.

  When the opening / closing means is closed, the detected value is the terminal voltage of the power storage device, and therefore it is considered that the detected value does not become an excessively low voltage or an excessively high voltage. On the other hand, when the opening / closing means is in an open state or when the terminal voltage detecting means is in an abnormal state, the detected value can be excessively high voltage or excessively low voltage.

  In view of this point, the above invention constitutes an abnormality diagnosis means.

  In addition, about the expansion of the concept regarding the following typical embodiment concerning this invention, it describes in the column of "other embodiment" after typical embodiment.

The system block diagram concerning one Embodiment. The figure which shows the function which diagnoses the presence or absence of the disconnection of the relay drive signal line concerning the embodiment. The flowchart which shows the procedure of the diagnostic process of the presence or absence of disconnection of the relay drive signal line and total voltage detection line concerning the embodiment.

  Hereinafter, an embodiment in which a power supply control device according to the present invention is applied to a monitoring device for a secondary battery for a house will be described with reference to the drawings.

  A high-voltage battery 10 shown in FIG. 1 is an assembled battery as a series connection body of battery cells C11 to Cnm, and assumes a normal open-end voltage of, for example, 100 V or more. In the present embodiment, a lithium ion secondary battery is assumed as the battery cell Cij (i = 1 to n, j = 1 to m). The high voltage battery 10 is a secondary battery that is installed in a house and whose charging and discharging are controlled based on the demand and supply of electric power in the house. In addition, the high voltage battery 10 is insulated with respect to the ground location. For this reason, the negative electrode potential of the high voltage battery 10 does not become the ground potential. Such a setting may be realized, for example, by setting the median value of the positive electrode potential and the negative electrode potential of the high-voltage battery 10 to the ground potential. This can be realized by providing a series connection of resistors or capacitors between the positive electrode and the negative electrode of the high-voltage battery 10 and grounding the connection point between the resistors (capacitors).

  The high voltage battery 10 is connected to a power conversion circuit 14 including a DC / AC conversion circuit and the like via relays SMRa and SMRc. Then, for example, on the condition that an operation request for an air conditioner in a house is generated, the DC power of the high voltage battery 10 is converted into AC power by the power conversion circuit 14 and supplied to the air conditioner.

  The power conversion circuit 14 includes a smoothing capacitor 16. Correspondingly, a precharge resistor 12 and a relay SMRb are further provided between the high voltage battery 10 and the power conversion circuit 14. As a result, when the high voltage battery 10 and the power conversion circuit 14 are connected under a condition where the charging voltage of the smoothing capacitor 16 is low, the relay SMRb is closed before the relay SMRb is closed. The battery 10 and the power conversion circuit 14 can be connected with high impedance. Thereby, it is possible to avoid a situation in which an inrush current flows from the high voltage battery 10 to the smoothing capacitor 16.

  In the present embodiment, the relays SMRa, SMRb, and SMRc are all electromagnetic relays. In the present embodiment, the relays SMRa, SMRb, and SMRc are normally open types.

  The battery cells C11 to Cnm constituting the high voltage battery 10 constitute a module by m adjacent each other, and the battery cells Ci1 to Cim constituting each module are monitored by the monitoring unit Ui. The monitoring unit Ui detects terminal voltages (cell voltages Vij) of the battery cells Ci1 to Cim to be monitored and outputs them to the central processing unit (CPU 50) via the interface 18. Here, the CPU 50 uses the ground as a reference potential. The interface 18 includes an insulating communication means such as a photocoupler that propagates a signal while insulating the input side and the output side.

  The CPU 50 performs a process of monitoring the state of the high voltage battery 10 based on the cell voltage Vij detected by the monitoring unit Ui. Further, the CPU 50 performs a process of opening / closing the relays SMRa, SMRb, and SMRc via the drive units DUa, DUb, and DUc.

  In the drive units DUa, DUb, and DUc according to the present embodiment, as illustrated for the drive unit DUa, a loop path including the coil 21 of the relay SMRa and the power source 20 includes an N-channel MOS field effect transistor (switching element 24 for driving control). ). The gate of the drive control switching element 24 is operated by the CPU 50 via the drive circuit 26. Here, the drive circuit 26 is a circuit capable of applying a voltage for turning it on to the gate of the drive control switching element 24. This can be realized, for example, by configuring the drive circuit 26 with a booster circuit. According to such a configuration, when the output signal Dout from the CPU 50 is logic L, the drive control switching element 24 is turned off and the loop path is opened, so that the relay SMRa is opened.

  The drive units DUa, DUb, and DUc further function to diagnose the presence or absence of disconnection of the relay drive signal line Ll that connects between the drive unit DUa (DUb, DUc) and the relay SMRA (SMRb, SMRc), as illustrated for the drive unit DUa. (Opening / closing diagnosis means). This is because the potential fixing resistor 22 is connected in parallel to the drive control switching element 24, and the potential Vd between the drive control switching element 24 and the coil 21 when the drive control switching element 24 is instructed to be turned off is referred to. Is. That is, the potential Vd at this time is the potential fixing resistor 22 because the loop path including the power source 20, the potential fixing resistor 22 and the coil 21 is closed unless the relay drive signal line Ll is disconnected. Is about the voltage of the power supply 20, and the potential Vd becomes the ground potential. On the other hand, if the relay drive signal line Ll is disconnected, the potential Vd is pulled up to the potential of the power source 20 by the relay drive signal line Ll.

  Specifically, a resistor 30 and an N-channel MOS field effect transistor (switching element 32) connected in series, and a resistor 34 and an N-channel MOS field effect transistor (switching element 36) are connected in series between the power supply 28 and the ground. A parallel connection body is provided with the connection body. The gate of the switching element 32 is connected between the drive control switching element 24 and the coil 21, and the gate of the switching element 36 is connected between the resistor 30 and the switching element 32. The potential between the resistor 34 and the switching element 36 is input to the CPU 50 as the input signal Din. This input signal Din is a signal indicating a diagnosis result of the presence or absence of disconnection of the relay drive signal line Ll. FIG. 2 shows the relationship between the output signal Dout and the input signal Din for each of the normal operation and the disconnection.

  As shown in the figure, during normal operation, the input signal Din becomes a logic H or a logic L depending on whether the output signal Dout is a logic H or a logic L, but the relay drive signal line Ll At the time of disconnection, the input signal Din is always logic H. Therefore, when the output signal Dout is logic L, the input signal Din becomes logic H, so that it can be diagnosed that the relay drive signal line Ll is disconnected.

  The CPU 50 uses the detected value of the charging voltage of the smoothing capacitor 16 when performing the precharging process of the smoothing capacitor 16 using the relay SMRb. This is realized by providing means for detecting a voltage between relays SMRa, SMRb, SMRc and power conversion circuit 14. In other words, voltage dividing resistors 40 and 42 are connected between relays SMRa, SMRb, SMRc and power conversion circuit 14 via total voltage detection line Ld. The voltage (total voltage Vb) divided by the voltage dividing resistors 40 and 42 is converted into digital data by the analog-digital converter 44. The total voltage Vb converted into digital data is output to the CPU 50 via the isolator 46. Here, the isolator 46 includes an insulating communication means for propagating a signal while insulating the input side and the output side.

  According to such a configuration, the CPU 50 can perform the precharge process using the total voltage Vb as the detected value of the charging voltage of the smoothing capacitor 16 in a state where the relays SMRa, SMRb, and SMRc are open. That is, the relays SMRb and SMRc are closed, and the difference between the charging voltage of the smoothing capacitor 16 and the terminal voltage of the high-voltage battery 10 is equal to or less than a specified value, so that the relay SMRa is closed and the relay SMRb is opened. . The terminal voltage of the high voltage battery 10 is calculated by adding the cell voltage Vij detected by the monitoring unit Ui.

  In the CPU 50, on the condition that the relays SMRa and SMRc are in the closed state, the terminal voltage of the high voltage battery 10 that is grasped from the cell voltage Vij and the terminal of the high voltage battery 10 that is grasped from the total voltage Vb. Based on the comparison with the voltage, it has a function of diagnosing whether the monitoring unit Ui is abnormal. This is because, for example, the monitoring unit Ui has an abnormality when the difference between the terminal voltage of the high voltage battery 10 calculated by the addition operation of the cell voltage Vij and the terminal voltage of the high voltage battery 10 determined by the total voltage Vb is large. This can be realized by diagnosis.

  The monitoring unit Ui, drive units DUa, DUb, DUc, CPU 50, voltage dividing resistors 40, 42, analog-digital converter 44, isolator 46, and the like are configured on one substrate 60. The relay drive signal line Ll and the total voltage detection line Ld also serve as an electrical path that connects a member in the substrate 60 and a member outside the substrate 60.

  The CPU 50 also performs a process of diagnosing whether the relay drive signal line Ll or the total voltage detection line Ld is disconnected. FIG. 3 shows the procedure of this process. This process is repeatedly executed at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not the relays SMRa and SMRc are in a closed state. This process is for determining whether or not an execution condition for diagnosis of whether or not the relay drive signal line Ll or the total voltage detection line Ld is disconnected is satisfied. If an affirmative determination is made in step S10, it is determined in step S12 whether or not the total voltage Vb is equal to or less than the specified voltage Vth. This process is for determining whether or not the relay drive signal line Ll or the total voltage detection line Ld is broken. That is, when the total voltage detection line Ld is disconnected, the total voltage Vb divided by the voltage dividing resistors 40 and 42 becomes zero. Further, if the relay drive signal line Ll is disconnected, when the power conversion circuit 14 is discharging the high voltage battery 10, the charging energy of the smoothing capacitor 16 is rapidly reduced and the charging voltage is also reduced to zero. descend. Further, when the operation of the power conversion circuit 14 is stopped, the charging energy of the smoothing capacitor 16 is discharged by the voltage dividing resistors 40 and 42, so that the charging voltage gradually decreases to zero.

  In the present embodiment, the specified voltage Vth is set to a low voltage that cannot be taken as a normal terminal voltage of the high-voltage battery 10. This can be realized by setting the lower limit voltage to a value smaller than the value obtained by adding all the battery cells C11 to Cnm when the lower limit voltage is defined for each battery cell Cij of the high voltage battery 10. However, the specified voltage Vth is preferably set to a value larger than the detection accuracy of the analog-digital converter 44.

  If an affirmative determination is made in step S12, it is considered that the disconnection has occurred in the relay drive signal line Ll or the total voltage detection line Ld, and therefore, the process proceeds to step S14 and the relays SMRa and SMRc are opened. This process is a fail-safe process for prohibiting charge / discharge control of the high-voltage battery 10, and is also a precondition for identifying which one of the relay drive signal line Ll and the total voltage detection line Ld is disconnected. .

  In a succeeding step S16, it is determined whether or not the input signal Din to the CPU 50 is logic H. If it is logic H, it is determined in step S18 that the relay drive signal line Ll is disconnected. If it is logic L, it is determined in step S20 that the total voltage detection line Ld is disconnected. This is because the input signal Din when the relays SMRa and SMRc are in the open state becomes logic “H” when the relay drive signal line Ll is disconnected as shown in FIG. .

  When the processes in steps S18 and S20 are completed, in step S22, a process for notifying the user is performed, and a process for storing the diagnosis result in the nonvolatile memory 52 shown in FIG. 1 is performed. Here, the diagnosis result is identification information indicating whether the relay drive signal line Ll is broken or the total voltage detection line Ld is broken. As a result, the maintenance person who has been contacted by the user can access the nonvolatile memory 52 to grasp whether the relay drive signal line Ll is disconnected or the total voltage detection line Ld is disconnected. As a result, the repair can be completed by a simple process of replacing the relay drive signal line Ll or the total voltage detection line Ld.

  Note that the non-volatile memory is a storage unit that stores and holds data regardless of whether or not power is supplied, such as an electrically rewritable read-only memory.

When the process of step S22 is completed or when a negative determination is made in steps S10 and S12, the series of processes is temporarily terminated.
<Other embodiments>
The above embodiment may be modified as follows.

"Opening and closing means"
Relays SMRa, SMRb, and SMRc are not limited to electromagnetic relays. For example, it may be a semiconductor relay composed of MOS field effect transistors.

  It is not limited to the normally open type. Even in the case of a normally closed type, it is assumed that the relay drive signal line Ll is unintentionally opened due to, for example, a short circuit with the battery when the operation is closed. Yes. In this case, by making an affirmative determination in step S12 of FIG. 3, it can be diagnosed that the relay drive signal line Ll is short or the total voltage detection line Ld is disconnected.

"Terminal voltage detection means"
The analog signal obtained by dividing the terminal voltage of the high voltage battery 10 is not limited to a digital signal. For example, a differential amplifier circuit that reduces and converts the absolute value of the terminal voltage of the high-voltage battery 10 may be provided, and the output voltage of the differential amplifier circuit may be converted into a digital signal. In this case, it is possible to satisfy the insulation requirement by increasing the resistance value of the resistor connected to the input terminal of the operational amplifier constituting the differential amplifier circuit. In this case, the isolator 46 is provided. No configuration is possible.

"Abnormality diagnosis methods"
For example, when an affirmative determination is made in step S12 of FIG. 3, the disconnection of the total voltage detection line Ld is diagnosed when the decrease rate of the total voltage Vb is large, and the relay drive signal is detected when the decrease rate of the total voltage Vb is small. You may diagnose with the disconnection of the line Ll. This is because, when the relay drive signal line Ll is disconnected, the detection value of the total voltage Vb decreases as the charge of the smoothing capacitor 16 decreases, so that the decrease rate is smaller than the disconnection of the total voltage detection line Ld. In view of this.

  It is not limited to being configured by software processing means (CPU 50), but may be configured by hardware processing means.

“Setting the specified range”
In the above embodiment, the specified voltage Vth is set to a low voltage (fixed value) that is assumed to be impossible when the terminal voltage of the high-voltage battery 10 is normal, but the present invention is not limited to this. For example, the specified voltage Vth may be variably set according to the charging rate of the high voltage battery 10.

  Further, when the relay drive signal line Ll is disconnected during the charging process of the high voltage battery 10, and the relays SMRa and SMRc are opened, the detected value of the total voltage Vb increases. For this reason, in the process of step S12 shown in FIG. 3, the process of comparing with the threshold voltage for determining whether or not the total voltage Vb is excessively high may be performed. In this case, when the total voltage Vb is excessively high, it can be diagnosed that the relay drive signal line Ll is broken, and when the total voltage Vb is equal to or lower than the specified voltage Vth, it can be diagnosed that the total voltage detection line Ld is broken.

About the diagnosis execution period
It is not limited to the period in which relays SMRa and SMRc are closed. For example, the precharge process may be performed by closing relay SMRb. However, in this case, it is desirable that the specified voltage Vth is increased by increasing the elapsed time from the start timing of the precharge process. Alternatively, the diagnosis execution start timing may be after a predetermined time has elapsed after the start of the precharge process.

"About fail-safe treatment"
As described above in the section of “abnormality diagnosis means”, when an affirmative determination is made in step S12 of FIG. 3, the disconnection of the total voltage detection line Ld and the relay drive signal line Ll based on the decrease rate of the total voltage Vb If the total voltage detection line Ld is disconnected, the relays SMRa and SMRc need not be opened. However, in this case, since the function of diagnosing the presence or absence of abnormality of the monitoring unit Ui is lost, it is desirable to limit the output of the high voltage battery 10 more than normal.

"About the energization circuit"
The circuit configuration is not limited to the drive unit DUa shown in FIG. For example, if the drive control switching element 24 opens and closes between the coil 21 and the ground, the potential fixing resistor 22 is connected in parallel to the drive control switching element 24 so that the coil 21 and the drive control are connected. The potential between the switching elements 24 may be pulled down.

"About open / close diagnostic means"
The means for diagnosing the presence / absence of an abnormality based on the potential Vd between the coil 21 and the drive control switching element 24 is not limited to the means provided with the switching elements 32, 36 and the like. For example, a comparator that compares the potential Vd between the coil 21 and the drive control switching element 24 with a predetermined potential may be provided. Further, the CPU 50 may be used. That is, the potential Vd between the coil 21 and the drive control switching element 24 may be converted into digital data in the CPU, and the presence or absence of abnormality may be diagnosed based on the value.

About identification means
The fact that the identification means for identifying the disconnection of the relay drive signal line Ll and the disconnection of the total voltage detection line Ld using the input signal Din is not essential is as described in the section “Regarding the abnormality diagnosis means”.

About the board
The present invention is not limited to a single substrate 60 on which terminal voltage detection means (analog / digital converter 44), opening / closing operation means (CPU 50), and abnormality diagnosis means (CPU 50) are formed. For example, the substrates on which the terminal voltage detection means (analog / digital converter 44), the abnormality diagnosis means (CPU 50) and the opening / closing operation means (CPU 50) are formed may be different substrates. Even in this case, it is still easy to replace the abnormal part by providing the identification means.

"About storage means"
Regardless of whether power is supplied or not, the present invention is not limited to a memory (nonvolatile memory 52) that stores and holds data. For example, it may be a so-called backup RAM that maintains the power supply state regardless of whether the CPU 50 or the like is activated.

About power storage devices
For example, a fuel cell may be used. Moreover, it is not restricted to what is installed in a house, For example, a vehicle-mounted storage battery may be sufficient. However, in this case, it is desirable to enable the limp home process instead of the fail safe process in which the relays SMRa and SMRc are opened immediately after an affirmative determination is made in step S12 of FIG. For example, in a hybrid vehicle including an engine and a motor as an in-vehicle main machine, when the relay drive signal line Ll is disconnected, the engine travel is selected, and when the total voltage detection line Ld is disconnected, the motor is selected. This can be realized as a process for selecting motor travel while restricting the output.

  10. High voltage battery (one embodiment of power storage device), SMRa, SMRb, SMRc ... relay (one embodiment of opening / closing means).

Claims (6)

Open / close means (SMRa, SMRb, SMRc) for opening / closing between the power storage device (10) and the power conversion circuit (14);
An opening / closing operation means (50) for opening / closing the opening / closing means;
Terminal voltage detection means (40, 42, 44) connected between the opening / closing means and the power conversion circuit for detecting a terminal voltage of the power storage device;
In the situation where the opening / closing means is closed by the opening / closing operation means, an abnormality occurs in either the opening / closing means or the terminal voltage detecting means based on the detection value of the terminal voltage detecting means being out of a predetermined range. An abnormality diagnosis means (50) for diagnosing the effect;
A power supply control device comprising:   2. The power supply control device according to claim 1, wherein the opening / closing operation means includes a fail-safe processing means for opening / closing the opening / closing means when the abnormality diagnosis means diagnoses that any abnormality has occurred. . A drive control switching element (24) for opening and closing a loop circuit including the switching means and the power source (20), and an energization circuit including a potential fixing resistor (22) connected in parallel to the drive control switching element;
Open / close diagnosis means (28, 30, 32, 34, 36) for diagnosing the presence / absence of abnormality of the open / close means based on the potential between the potential fixing resistor and the open / close means;
With
The opening and closing means is a normally open type,
The opening / closing operation means opens and closes the opening / closing means by an on / off operation of the drive control switching element,
The abnormality diagnosing means determines which of the opening / closing means and the terminal voltage detecting means is abnormal based on a diagnosis result by the opening / closing diagnosis means when the opening / closing means is opened by the fail safe processing means. The power supply control device according to claim 2, further comprising identification means for identifying.   The power supply control device according to claim 3, further comprising storage means (52) for storing an identification result obtained by the identification means. Each of the opening / closing operation means, the terminal voltage detection means, and the abnormality diagnosis means is formed on a substrate (60),
The electrical path connecting the open / close operation means and the open / close means, and the electrical path connecting the terminal voltage detection means and the power storage device are all wires (Ld, Ll) externally attached to the substrate. The power supply control device according to claim 3, further comprising:   The said electrical storage apparatus is an assembled battery as a serial connection body of a battery cell (Cij: i = 1-n, j = 1-m), The any one of Claims 1-5 characterized by the above-mentioned. Power control device.

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