JP2004177208A - Failure detection system of voltage detection circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely determine the presence or absence of any failure on a voltage detection circuit while inhibiting that device configuration is complicated. <P>SOLUTION: When it is determined that a cell voltage of any capacitor cell exceeds a prescribed regenerative limit voltage VR, a control unit 17 anticipates the total voltage (release determination voltage SVL) when the cell voltage of the capacitor cell reaches a prescribed determination voltage VT below the regenerative limit voltage VR, based on a detected total voltage detection value SVE. When it is detected that the detection value SVE is below the voltage SVL in the state that it is continued that a cell voltage of any capacitor cell exceeds a prescribed voltage VR, a control unit 17 determines that the detection value of the cell voltage of the capacitor cell is abnormal, and determines that failure is generated in a cell voltage detection circuit of a protective device 16. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a failure detection device for a voltage detection circuit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a battery pack (battery) formed by connecting a plurality of unit cells including, for example, a secondary battery in series, a cell voltage detection circuit and a bypass circuit connected in parallel to each unit cell are provided. It is determined whether each unit cell is in a fully charged state according to a voltage between terminals detected by a circuit, and a charging current for a cell determined to be in a fully charged state is supplied to a bypass circuit to allow each unit cell to be charged. There is known a battery charger that adjusts the variation of the inter-terminal voltage and sets the charging current to each unit cell according to the detected inter-terminal voltage (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. Hei 4-29932
[Problems to be solved by the invention]
By the way, in the battery charger according to the example of the related art, when determining whether each unit cell is in a fully charged state according to a terminal voltage detected by a cell voltage detection circuit, the cell voltage detection circuit If a failure occurs, there arises a problem that accurate determination becomes difficult.
The present invention has been made in view of the above circumstances. For example, it is possible to accurately determine the presence or absence of a failure in a voltage detection circuit while suppressing the complexity of the device configuration by newly providing a failure detection device or the like. It is an object of the present invention to provide a failure detection device for a voltage detection circuit that can perform the detection.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, a failure detection device for a voltage detection circuit according to the present invention includes a plurality of cells (for example, capacitor cells in the embodiments) connected in series. Failure detection of a voltage detection circuit including cell voltage detection means (for example, a cell voltage detection circuit in the embodiment) for detecting a voltage between terminals of each of the cells of the power storage device (for example, the capacitor 13 in the embodiment). A total voltage detecting means (for example, the voltage sensor 22 in the embodiment) for detecting a total voltage which is a sum of voltages between terminals of the plurality of cells; and a terminal of any one of the plurality of cells. A cell voltage determination unit (for example, step S02 in the embodiment) for determining that the inter-voltage has exceeded a predetermined voltage (for example, the regeneration limit voltage VR in the embodiment); When the inter-terminal voltage of any of the cells exceeds the predetermined voltage, a release determination voltage (for example, a release determination voltage SVL in the embodiment) is set based on the total voltage detected by the total voltage detection means. And the voltage between terminals of the cell determined to have exceeded the predetermined voltage is determined by the total voltage detection value detected by the total voltage detection means. When the voltage is lower than the release determination voltage (for example, “NO” side in step S10 in the embodiment), when the state in which the voltage exceeds the predetermined voltage continues (for example, in step S02 in the embodiment). YES)), and a failure determination unit (for example, step S07 in the embodiment) that determines that the voltage detection circuit has a failure.
[0006]
According to the failure detection device for a voltage detection circuit having the above-described configuration, the cell voltage determination unit determines whether or not the voltage between the terminals of any of the cells performs a predetermined voltage, for example, whether or not to discharge a cell that may be overcharged. It is determined that the judgment value or the like has been exceeded. The release determination voltage setting means determines that the release determination voltage, for example, exceeds a predetermined voltage, based on the total voltage detected by the total voltage detection means when the voltage between the terminals of any of the cells exceeds a predetermined voltage. A predicted value of the total voltage when the voltage between the terminals of the cell reaches the determination value for canceling the discharge processing of the cell, and the like are set.
The failure determination means is configured to determine that the voltage between the terminals of the cells determined to exceed the predetermined voltage is equal to or higher than the predetermined voltage even when the detected value of the total voltage detected by the total voltage detection means falls below the release determination voltage. Is determined to be abnormal, it is determined that a failure has occurred in the voltage detection circuit.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a failure detection device for a voltage detection circuit according to an embodiment of the present invention will be described with reference to the accompanying drawings.
A failure detection device 10 for a voltage detection circuit according to the present embodiment is mounted on a vehicle such as a fuel cell vehicle or a hybrid vehicle, and for example, as shown in FIG. 1, a fuel cell 11 and a current / voltage controller 12 , A capacitor 13, an output controller 14, a traveling motor 15, a protection device 16, a control device 17, a current sensor 21, a voltage sensor 22, a capacitor temperature sensor 23, and an accelerator opening sensor 31. The fuel cell vehicle including the brake switch 32 and the IG switch 33 includes, for example, the protection device 16, the control device 17, and the voltage sensor 22.
[0008]
The fuel cell 11 sandwiches a solid polymer electrolyte membrane composed of a cation exchange membrane or the like between a fuel electrode (anode) composed of an anode catalyst and a gas diffusion layer and an oxygen electrode (cathode) composed of a cathode catalyst and a gas diffusion layer. The fuel cell is formed by laminating a large number of fuel cells each having the above-mentioned electrolyte electrode structure sandwiched between a pair of separators.
A fuel gas (reaction gas) composed of hydrogen is supplied to the anode of the fuel cell 11 from a high-pressure hydrogen tank, and hydrogen ionized by a catalytic reaction on the anode catalyst of the anode is converted into a moderately humidified solid polymer electrolyte. The electrons move to the cathode via the membrane, and electrons generated by the movement are taken out to an external circuit and used as DC electric energy. Air, which is an oxidizing gas containing oxygen (reactive gas), is supplied to the cathode by an air compressor. At the cathode, hydrogen ions, electrons, and oxygen react to generate water.
[0009]
The generated current taken out of the fuel cell 11 is input to a current / voltage controller 12, and the current / voltage controller 12 includes a capacitor 13 that constitutes a power storage device, such as an electric double layer capacitor or an electrolytic capacitor. It is connected.
The fuel cell 11 and the capacitor 13 are connected in parallel to a traveling motor 15 as an electric load via an output controller 14.
The current / voltage controller 12 includes, for example, a DC-DC chopper and the like. The current / voltage controller 12 generates electric power extracted from the fuel cell 11 based on a current command value output from the control device 17, that is, a power generation command for the fuel cell 11. Controls the current value of the current.
[0010]
The output controller 14 includes, for example, a PWM inverter based on pulse width modulation (PWM), and controls the driving and the regenerative operation of the traveling motor 15 according to a control command output from the control device 17. For example, at the time of driving the traveling motor 15, the DC power output from the current / voltage controller 12 and the capacitor 13 is converted into three-phase AC power based on the torque command output from the control device 17 to the traveling motor 15. Supply. On the other hand, during regeneration of the traveling motor 15, the three-phase AC power output from the traveling motor 15 is converted into DC power, and the capacitor 13 is charged.
The traveling motor 15 is, for example, a permanent magnet type three-phase AC synchronous motor using a permanent magnet as a field, and is driven and controlled by three-phase AC power supplied from the output controller 14. When the driving force is transmitted from the driving wheels to the traveling motor 15 when the vehicle decelerates, the traveling motor 15 functions as a generator to generate a so-called regenerative braking force, and recovers the kinetic energy of the vehicle body as electric energy. I do.
[0011]
The capacitor 13 is configured by connecting a plurality of capacitor cells, such as an electric double layer capacitor and an electrolytic capacitor, in series, and the capacitor 13 is connected to a voltage detection line connected to the input / output terminal of each capacitor cell. The protection device 16 is connected.
The protection device 16 includes, for example, a cell voltage detection circuit that detects a terminal voltage (cell voltage) of each capacitor cell, and a bypass circuit that can bypass a charging current that flows through each capacitor cell and discharge each capacitor cell. , A bypass control unit, and a cell voltage determination unit. The cell voltage detection circuit and the bypass circuit are connected in parallel to each capacitor cell via a voltage detection line.
[0012]
The bypass circuit includes, for example, a bypass resistor and a switching element capable of switching on / off of energization to the bypass resistor.
The bypass control unit controls the on / off operation of the switching element of the bypass circuit, and controls the control command output from the control device 17 or the cell voltage of the capacitor cell to a predetermined regenerative limiting voltage VR (for example, VR = 2). .5V), and outputs a logic "high" level ON signal for setting the switching element to the ON state in accordance with the determination result indicating that the switching element has exceeded the threshold value. Thereby, the corresponding capacitor cell is discharged via the bypass resistor, and the charging current supplied to the capacitor cell is bypassed to the bypass resistor.
The cell voltage determination unit determines that each cell voltage has a predetermined regenerative limit voltage VR (for example, VR = 2.5 V) or a regenerative inhibition voltage VU having a value larger than the regenerative limit voltage VR (for example, VU = 2.7 V). It is determined whether or not each determination value such as the above has been exceeded, and each determination result is output to the bypass control unit and the control device 17.
[0013]
The control device 17 may control, for example, the operating state of the vehicle, the concentration of hydrogen contained in the reaction gas supplied to the anode of the fuel cell 11, the concentration of hydrogen contained in the exhaust gas discharged from the anode of the fuel cell 11, and the like. The flow rate of each reaction gas supplied from the air compressor and the hydrogen tank to the fuel cell 11 based on the power generation state of the fuel cell 11, for example, the output voltage of each of the plurality of fuel cells, the power generation current extracted from the fuel cell 11, and the like. And outputs a command value to the current / voltage controller 12 to control the power generation state of the fuel cell 11, and controls the current value of the power generation current extracted from the fuel cell 11.
[0014]
In addition, the control device 17 controls the power conversion operation of the PWM inverter provided in the output controller 14, and for example, when the driving motor 15 is driven, the control device 17 relates to the amount of depression of the accelerator pedal by the driver. A torque command is calculated based on the accelerator opening signal. Then, the controller 17 inputs this torque command to the output controller 14, whereby a pulse width modulation signal corresponding to the torque command is input to the PWM inverter, and each phase current for generating the requested torque is generated. It is output to each phase of the traveling motor 15.
Further, the control device 17 detects the state of the capacitor 13, for example, the detection result of the cell voltage of each capacitor cell output from each cell voltage detection circuit of the protection device 16, the temperature of the capacitor 13, the cell of a plurality of capacitor cells, and the like. The regenerative operation of the traveling motor 15 is controlled based on the detected value of the total voltage which is the sum of the voltages.
For this reason, the control device 17 includes, for example, a detection signal output from a current sensor 21 for detecting a current value of a generated current extracted from the fuel cell 11 and a voltage sensor 22 for detecting a total voltage which is a sum of cell voltages. , A detection signal output from a capacitor temperature sensor 23 that detects the temperature of the capacitor 13, a detection signal output from an accelerator opening sensor 31, and the presence or absence of a brake operation by the driver. A signal output from the brake switch 32 and a signal output from the IG switch 33 instructing the operation of the vehicle are input.
[0015]
Further, the control device 17 determines whether each determination result output from the cell voltage determination unit of the protection device 16, that is, whether each cell voltage has exceeded each determination value such as a predetermined regenerative limit voltage VR or a regenerative inhibition voltage VU. And the state of the capacitor 13, for example, the temperature of the capacitor 13, and the detected value of the total voltage which is the sum of the cell voltages of the plurality of capacitor cells (total voltage detection value SVE), the regenerative operation of the traveling motor 15. Control.
Further, as will be described later, when it is determined that the cell voltage of any one of the capacitor cells has exceeded the predetermined regenerative limit voltage VR, the control device 17 sets the cell voltage of the capacitor cell to the regenerative limit voltage VR or lower. The total voltage (that is, the release determination voltage SVL) when reaching the predetermined determination voltage VT is predicted. The control device 17 determines that the total voltage detection value SVE detected is lower than the release determination voltage SVL in a state where the state in which the cell voltage of any one of the capacitor cells has exceeded the predetermined regenerative limit voltage VR is continued. Is detected, it is determined that the detected value of the cell voltage of the capacitor cell is abnormal, and it is determined that a failure has occurred in the cell voltage detection circuit of the protection device 16.
[0016]
The failure detection device 10 of the voltage detection circuit according to the present embodiment has the above-described configuration. Next, the operation of the failure detection device 10 of the voltage detection circuit will be described with reference to the accompanying drawings.
[0017]
First, for example, in step S01 shown in FIG. 2, the cell voltage of each capacitor cell of the capacitor 13 is detected.
Next, in step S02, it is determined whether or not any of the cell voltages has exceeded a predetermined regeneration limit voltage VR (for example, VR = 2.5V).
If this determination is "YES", the flow proceeds to step S05 described later.
On the other hand, if the result of this determination is "NO", the flow proceeds to step S03.
In step S03, the flag value of the flag F indicating that the release determination voltage SVL has been set after any one of the cell voltages has exceeded the predetermined regeneration limiting voltage VR is set to zero, and the flag F is reset.
Then, in step S04, it is determined that the cell voltage detection circuit of the protection device 16 is normal, and a series of processing ends.
[0018]
In step S05, it is determined whether the flag value of the flag F is zero.
If the result of this determination is "NO", the flow proceeds to step S10 described later.
On the other hand, when the result of this determination is “YES”, the flow proceeds to step S06.
[0019]
In step S06, it is determined whether or not total voltage detection value SVE is greater than a predetermined total voltage determination value. Here, the predetermined total voltage determination value is, for example, a detection of a total voltage detection value SVE detected when any cell voltage exceeds a predetermined regenerative limit voltage VR (for example, VR = 2.5 V). It is a lower limit value or the like.
If the result of this determination is “NO”, the flow proceeds to step S07, where it is determined that the detected value of the cell voltage of the capacitor cell is abnormal, and it is determined that a failure has occurred in the cell voltage detection circuit of the protection device 16. Then, a series of processing ends.
On the other hand, when the result of this determination is “YES”, the flow proceeds to step S08.
In step S08, the release determination voltage SVL is set.
Here, for example, the cell voltage of the capacitor cell that has exceeded the predetermined regenerative limit voltage VR is equal to or lower than the regenerative limit voltage VR (for example, VR = 2.5 V) and is equal to or less than the predetermined determination voltage VT (for example, VT = 2.4 V, etc.). ) Is predicted, and this predicted value is set as the release determination voltage SVL. For example, the sum ((VR−VT) × N) of the difference between the regeneration limit voltage VR and the determination voltage VT for the number N of capacitor cells is subtracted from the total voltage detection value SVE of the capacitor 13 detected at this time. The obtained value is set as the release determination voltage SVL.
[0020]
Then, in step S09, the flag value of the flag F indicating that the release determination voltage SVL has been set after any one of the cell voltages exceeds the predetermined regenerative limit voltage VR is set to 1, and the process proceeds to step S10.
Then, in step S10, it is determined whether the total voltage detection value SVE is higher than the release determination voltage SVL.
If the result of this determination is "NO", the flow proceeds to step S07 described above, where it is determined that the detected value of the cell voltage of the capacitor cell is abnormal, and that a failure has occurred in the cell voltage detection circuit of the protection device 16. After making the determination, the series of processing is terminated.
On the other hand, if the result of this determination is "YES", the flow proceeds to step S04 described above, where it is determined that the cell voltage detection circuit of the protection device 16 is normal, and a series of processing ends.
[0021]
As described above, according to the failure detection device 10 of the voltage detection circuit according to the present embodiment, for example, a dedicated inspection device or the like is newly added based on the detected value of the cell voltage of each capacitor cell and the total detected voltage value SVE. , It is possible to easily and accurately determine whether or not the voltage detection circuit for detecting the cell voltage has a failure.
[0022]
In the above-described embodiment, the power storage device that exchanges electric energy with the traveling motor 15 is the capacitor 13. However, the present invention is not limited to this. For example, a plurality of cells including a secondary battery such as a lithium ion battery may be used. May be connected in series.
[0023]
【The invention's effect】
As described above, according to the voltage detection circuit failure detection device of the present invention described in claim 1, for example, it is easy to accurately determine whether or not a failure has occurred in the voltage detection circuit while suppressing the device configuration from becoming complicated. Can be determined.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a failure detection device for a voltage detection circuit according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation of the failure detection device for the voltage detection circuit shown in FIG.
[Explanation of symbols]
10 Voltage detection circuit failure detection device 13 Capacitor (power storage device)
22 Voltage sensor (voltage detection means)
Step S02 Cell voltage determination means Step S08 Release determination voltage setting means Step S07 Failure determination means

Claims (1)

A failure detection device for a voltage detection circuit including cell voltage detection means for detecting a voltage between terminals of each of the cells of the power storage device in which a plurality of cells are connected in series,
Total voltage detection means for detecting a total voltage of the power storage device, which is a sum of voltages between terminals of the plurality of cells,
Cell voltage determining means for determining that the voltage between terminals of any of the plurality of cells has exceeded a predetermined voltage,
When the voltage between the terminals of any of the cells exceeds the predetermined voltage, a release determination voltage setting unit that sets a release determination voltage based on the total voltage detected by the total voltage detection unit,
When the inter-terminal voltage of the cell determined to have exceeded the predetermined voltage is lower than the release determination voltage when the detected value of the total voltage detected by the total voltage detecting means is lower than the predetermined voltage, A failure detection device for a voltage detection circuit, comprising: failure determination means for determining that a failure has occurred in the voltage detection circuit when the voltage detection circuit continues.

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