KR102421368B1 - Apparatus and method for diagnosing current sensor error - Google Patents

Abstract

A current sensor error diagnosis apparatus and method are disclosed. The apparatus for diagnosing a current sensor error according to the present invention, at each of a plurality of predetermined sampling time points, sets a first current value measured by the first current sensor and a second current value measured by the second current sensor at the same timing a current value sampling unit for sampling; a first determination unit for determining whether a difference between the two current values exceeds a predetermined reference value for each of the plurality of first and second current values sampled at the same timing; A first frequency is calculated by accumulating the number of times it is determined that the magnitude of the difference value does not exceed the reference value, and calculating a second frequency by accumulating the number of times it is determined that the magnitude of the difference value exceeds the reference value. wealth; and calculating an error determination ratio corresponding to a ratio of the first frequency to the sum of the first and second frequencies, and comparing the calculated error determination ratio with a predetermined reference ratio to determine whether an error occurs By including the 2 determination unit, it can be applied to various systems in the same way regardless of the type of current source or voltage characteristics, and errors in the case of a measurement error occurring in the current value due to a decrease in the response speed of the current sensor or a phase delay, etc. In addition to being able to diagnose, it has strong characteristics against instantaneous current changes or frequency changes, and improves the accuracy and reliability of error diagnosis.

Description

Apparatus and method for diagnosing current sensor error

The present invention relates to an apparatus and method for diagnosing a current sensor error, and to an apparatus and method for diagnosing a current sensor error using a relative relationship between two current sensors configured to measure a current value of the same current.

In general, a current sensor refers to a sensor that senses a direct current or an alternating current using a Hall sensor or a sense resistor. Recently, as the use of secondary battery cells has been expanded to fields such as electric vehicles (EVs, HEVs, PHEVs) and large-capacity power storage devices (ESS), as well as mobile devices such as mobile phones and tablet PCs, secondary battery cells Interest and requests for technology for accurately diagnosing whether an error occurs in a current sensor that detects the charge/discharge current of the device are rapidly increasing.

However, as disclosed in Korean Patent Application Laid-Open No. 10-2010-0099461, the prior art measures the voltage and current of the battery pack for a predetermined time and compares the voltage change and current change amount with the voltage reference value and the current reference value, respectively. In order to diagnose an error, completely different reference values must be used depending on the type of system using the current sensor, the type of current source, voltage characteristics, etc., and there is a problem in that it is difficult to apply to various systems.

In addition, as disclosed in Japanese Patent Application Laid-Open No. 1997-023501, the prior art diagnoses that an error has occurred when the output of the current sensor is maintained in the 0 state for a predetermined time, so the error occurs when the current sensor does not operate at all. However, there is a problem that errors cannot be diagnosed when a measurement error occurs in the current value due to a decrease in response speed or a phase delay of the current sensor.

The present invention was devised under the background of the prior art as described above, and can be applied to the error diagnosis of the current sensor in the same way regardless of the type of system using the current sensor, the type of current source or voltage characteristics, etc., and the response speed of the current sensor It can accurately diagnose errors in the case of measurement errors occurring in the current value due to degradation or phase delay, as well as having strong characteristics against instantaneous current changes or frequency changes, and can improve the accuracy and reliability of error diagnosis. An object of the present invention is to provide an apparatus and method for diagnosing a current sensor error.

A current sensor error diagnosis apparatus according to the present invention for achieving the above technical problem receives the current values of the first current sensor and the second current sensor configured to measure the current value of the same current, the first current sensor and the second current sensor 2 a control unit that determines whether an error occurs in the current sensor; and a storage unit configured to receive and store the determination result of the control unit, wherein the control unit includes a first current value measured by the first current sensor and a second current sensor at each predetermined sampling time point. a current value sampling unit for sampling a second current value measured through ? at the same timing; a first determination unit for determining whether a difference between the two current values exceeds a predetermined reference value for each of the plurality of first and second current values sampled at the same timing; A first frequency is calculated by accumulating the number of times it is determined that the magnitude of the difference value does not exceed the reference value, and calculating a second frequency by accumulating the number of times it is determined that the magnitude of the difference value exceeds the reference value. wealth; and calculating an error determination ratio corresponding to a ratio of the first frequency to the sum of the first and second frequencies, and comparing the calculated error determination ratio with a predetermined reference ratio to determine whether an error occurs 2 includes a judging unit.

In an embodiment, when the calculated error determination ratio is equal to or greater than the reference ratio, the second determination unit determines that an error does not occur in the first current sensor and the second current sensor, and the calculated error determination ratio When this ratio is less than the reference ratio, it may be configured to determine that an error has occurred in at least one of the first current sensor and the second current sensor.

In an embodiment, the frequency calculator is configured to reset the first frequency and the second frequency to 0 after the second determination unit determines that an error does not occur in the first current sensor and the second current sensor. The current value sampling unit may be configured to resume sampling the current values for the first current sensor and the second current sensor when a next predetermined diagnosis time arrives.

In one embodiment, when the second determination unit determines that an error has occurred in at least one of the first current sensor and the second current sensor, the control unit is configured to generate a DTC (Diagnostic Trouble Code) indicating a current sensor error. It may further include an error information processing unit to generate and store in the storage unit.

In an embodiment, the apparatus further comprises an output unit for outputting visual information, wherein the error information processing unit includes an error in at least one of the first current sensor and the second current sensor, wherein the second determination unit has an error. When it is determined that a current sensor error has occurred, error information indicating that a current sensor error has occurred may be output as visual information through the output unit.

In an embodiment, the apparatus further includes a communication unit for performing wired communication or wireless communication, wherein the error information processing unit includes the second determination unit at least one of the first current sensor and the second current sensor. When it is determined that an error has occurred, it may be configured to transmit error information informing that a current sensor error has occurred to another device through the communication unit.

A battery management system according to the present invention for achieving the above technical problem includes the above-described current sensor error diagnosis apparatus.

In one embodiment, the error information processing unit, when the second determination unit determines that an error occurs in at least one of the first current sensor and the second current sensor, the first current sensor or the second current sensor The SOC estimation unit for estimating the state of charge (SOC) of the secondary battery cell by measuring the current value through .

A current sensor error diagnosis method according to the present invention for achieving the above technical problem is a method of diagnosing errors of a plurality of current sensors, wherein a processor of a battery management system (BMS) is configured to measure the current of the same secondary battery cell, ( a) At each of a plurality of predetermined sampling points, a first current value measured by a first current sensor among the plurality of current sensors and a second current value measured by a second current sensor among the plurality of current sensors are set at the same timing sampling to; (b) determining whether the magnitude of the difference between the two current values exceeds a predetermined reference value for each of the plurality of first and second current values sampled at the same timing; (c) calculating the first frequency by accumulating the number of times it is determined that the magnitude of the difference value exceeds the reference value, and calculating the second frequency by accumulating the number of times it is determined that the magnitude of the difference value does not exceed the reference value to do; and (d) calculating an error determination ratio corresponding to a ratio of the first frequency to the sum of the first and second frequencies, and comparing the calculated ratio with a predetermined reference ratio to determine whether an error occurs may include steps.

In an embodiment, in the step (d), when the calculated error determination ratio is equal to or greater than the reference ratio, it is determined that no errors have occurred in the first current sensor and the second current sensor, and the calculated error determination is performed. The method may include determining that an error has occurred in at least one of the first current sensor and the second current sensor when the ratio is less than the reference ratio.

In one embodiment, the method resets the first frequency and the second frequency to 0 after determining that errors do not occur in the first current sensor and the second current sensor in step (d); , may be configured to repeat the steps (a) to (d) when the next predetermined diagnosis time arrives.

In one embodiment, the method includes (e) when it is determined that an error has occurred in at least one of the first current sensor and the second current sensor in the step (d), DTC (Diagnostic Trouble) indicating a current sensor error Code) may be generated and stored in the storage unit of the BMS.

In one embodiment, in the method, (f) when it is determined that an error has occurred in at least one of the first current sensor and the second current sensor in step (d), error information notifying the fact that a current sensor error has occurred The method may further include outputting as visual information through the output unit of the BMS.

In one embodiment, in the method, (g) when it is determined that an error has occurred in at least one of the first current sensor and the second current sensor in step (d), error information notifying the occurrence of a current sensor error The method may further include transmitting to another device through the communication unit of the BMS.

In one embodiment, in the method, (h) when it is determined that an error occurs in at least one of the first current sensor and the second current sensor in step (d), the first current sensor or the second The method may further include requesting to stop estimating the SOC to the SOC estimating unit of the BMS that estimates the state of charge (SOC) of the secondary battery cell by using the current value of the current sensor.

According to the present invention, by diagnosing the errors of the current sensors using only the current values of the two current sensors, the errors of the current sensors are diagnosed in the same way regardless of the type of system using the current sensor, the type of the current source or the voltage characteristics, etc. and can be easily applied to various systems including a plurality of current sensors. The system may determine an average value of current values measured through a plurality of current sensors as a current measurement value, and at the same time reliably diagnose an error of the current sensor.

In addition, by comparing the current values measured by the two current sensors at the same time to determine whether an error occurs in the current sensor, the current value according to the error in case the current sensor does not operate at all, as well as the response speed decrease or phase delay of the current sensor Errors in the case of measurement errors can also be accurately diagnosed.

In particular, based on the difference between the current values actually measured by the two current sensors, it is repeatedly determined whether an error has occurred in the current sensor to accumulate the judgment results, and after calculating the frequency for each judgment result through the accumulated judgment results, By probabilistically determining whether or not a final error occurs again through the frequency of each determination result, it has a robust characteristic against instantaneous current or frequency change, and the accuracy and reliability of error diagnosis can be improved. In addition, when a high-frequency current is input, it is possible to fundamentally prevent a phenomenon in which a difference is generated between measured current values according to a cut-off frequency difference between the current sensors, so that the current sensor is misdiagnosed as an error.

Furthermore, those of ordinary skill in the art to which the present invention pertains will clearly understand from the following description that various embodiments according to the present invention can solve various technical problems not mentioned above.

The following drawings attached to this specification illustrate one embodiment of the present invention, and together with the detailed description to be described later serve to further understand the technical spirit of the present invention, the present invention is limited only to the matters described in such drawings should not be interpreted as
1 is a block diagram illustrating an apparatus for diagnosing a current sensor error according to an embodiment of the present invention.
2 is a block diagram showing an example of a control unit applied to the present invention.
FIG. 3 is a diagram illustrating a range of current values determined as a normal state and an error state in a rectangular coordinate system when a provisional error is determined according to a current difference value between two current sensors.
4 is a flowchart illustrating a method for diagnosing a current sensor error according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his or her application. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only one embodiment of the present invention and do not represent all the technical spirit of the present invention, so various equivalents that can be substituted for them at the time of the present invention It should be understood that there may be variations and examples.

In the embodiments described below, a secondary battery cell described as a current source of a current sensor is a generic term for secondary battery cells using a current sensor for SOC estimation and the like.

In addition, in the present invention, the secondary battery cell according to the type of positive electrode material, negative electrode material, electrolyte or separator used in the secondary battery cell, the type of packaging material used to package the secondary battery, the internal and external structure of the secondary battery cell, etc. Even if the name of is changed, all the corresponding cells may be included in the secondary battery cells.

In addition, the present invention provides a current sensor that not only diagnoses an error of a current sensor that measures the current of a secondary battery cell, but also measures the current of a battery pack realizing a high voltage by connecting a plurality of secondary battery cells in series; It should be clarified in advance that it can be applied to diagnosing errors such as a current sensor that measures the current of an electric motor of a hybrid vehicle.

1 is a block diagram illustrating an apparatus 100 for diagnosing a current sensor error according to an embodiment of the present invention.

Referring to FIG. 1 , an apparatus 100 for diagnosing a current sensor error according to the present invention is an apparatus for diagnosing an error occurring in at least one current sensor among a plurality of current sensors 12a and 12b configured to measure the same current, the BMS It may be configured as a device included in the (Battery Management System) 10 . According to an embodiment, the current sensor error diagnosis apparatus 100 may be configured as a separate device interworking with the BMS 10 . In this case, the current sensor error diagnosis apparatus 100 may be connected to the BMS 10 through a communication interface or an I/O interface, and may transmit error diagnosis information of the current sensor to the BMS 10 side.

The BMS 10 periodically measures and monitors the charge/discharge current, voltage, temperature, etc. of the secondary battery cell 20 , and estimates the SOC (State of Charge) of the secondary battery cell 20 , according to the estimation result. This is a battery management system that performs overall management of the secondary battery cells 20 , such as charging the secondary battery cells 20 through the charging unit 30 . To this end, the BMS 10 may include a plurality of current sensors 12a and 12b, a voltage sensor 14 , a temperature sensor 16 , an SOC estimation unit 18 , and the like.

The plurality of current sensors 12a and 12b measure the charging current or the discharging current of the secondary battery cell 20 at regular intervals. The plurality of current sensors 12a and 12b are configured to measure the same current. For example, a series circuit in which the plurality of current sensors 12a and 12b are connected in series may be configured to be connected in series on a line through which the charge/discharge current of the secondary battery cell 20 flows. As another example, if the plurality of current sensors 12a and 12b are all designed to have the same equivalent resistance, a parallel circuit connecting the plurality of current sensors 12a and 12b in parallel with each other is the charge of the secondary battery cell 20 . · It may be configured to be connected in series on a line through which a discharge current flows.

In one embodiment, when the BMS 10 measures current using a plurality of current sensors 12a and 12b connected in series with each other, the BMS 10 is measured through the plurality of current sensors 12a and 12b. The average value of the current values can be determined as the current measurement value, and at the same time, the error of the current sensor can be reliably diagnosed.

In another embodiment, when the BMS 10 measures current using a plurality of current sensors 12a and 12b connected in parallel, the BMS 10 is measured through a plurality of current sensors 12a and 12b. The sum of the current values may be determined as the measured value of the current.

The current measurement timing of the plurality of current sensors 12a and 12b may be controlled by the SOC estimation unit 18 while the SOC estimation process is in progress, and the current sensor error diagnosis apparatus ( It can be controlled by the control unit 110 of 100). As will be described again below, the control unit 110 of the current sensor error diagnosis apparatus 100 may be configured to include the SOC estimation unit 18 .

When the current measurement timing of the plurality of current sensors 12a and 12b is controlled by the control unit 110 in the current sensor error diagnosis process, each of the current sensors 12a and 12b transmits and receives an electrical signal through a conductive line It is electrically coupled to the control unit 110 through the. Each of the current sensors 12a and 12b measures the size of the charging current or the discharging current of the secondary battery cell 20 at the same timing every predetermined period under the control of the control unit 110 and indicates the size of the measured current. A signal may be output to the control unit 110 . The control unit 110 may determine a magnitude of a current according to a signal output from each current sensor and store the determined current value by itself or in the storage unit 120 .

Each of the current sensors 12a and 12b may be configured as a Hall sensor or sense resistor commonly used in the art. The Hall sensor or the sense resistor may be installed in a line through which a charging current or a discharging current flows. The control unit 110 may measure a voltage signal output from the Hall sensor or a voltage applied between both terminals of the sense resistor, and determine the magnitude of the charging current or the discharging current using the voltage signal or the measured voltage. The control unit 110 may include an analog-to-digital converter (ADC) to convert a voltage signal output from the Hall sensor or a voltage applied to both terminals of the sense resistor into a digital value.

A technique for measuring the size of the charging current or the discharging current of the secondary battery cell 20 using the Hall sensor or the sense resistor is obvious to those skilled in the art, and thus a detailed description thereof will be omitted.

On the other hand, the voltage sensor 14 and the temperature sensor 16 are mainly sensors used for SOC estimation or other management of the secondary battery cell 20 .

The voltage sensor 14 measures the voltage of the secondary battery cell 20 . To this end, the voltage sensor 14 is electrically coupled to the SOC estimation unit 18 so as to be able to send and receive electrical signals. The voltage sensor 14 measures the voltage applied between the positive electrode and the negative electrode of the secondary battery cell 20 at regular intervals under the control of the SOC estimation unit 18 and transmits a signal indicating the magnitude of the measured voltage to the SOC estimation unit ( 18) can be printed. The SOC estimation unit 18 may determine a voltage according to a signal output from the voltage sensor 14 and store the determined voltage value by itself or in the storage unit 120 of the BMS 10 .

The voltage sensor 14 may be configured with a voltage measuring circuit commonly used in the art. For example, the voltage measuring circuit may include a differential amplifier. Since the circuit configuration of the voltage sensor 14 for measuring the voltage of the secondary battery cell is obvious to those skilled in the art, a detailed description thereof will be omitted.

The temperature sensor 16 measures the temperature of the secondary battery cell 20 . The temperature measurement timing is controlled by the SOC estimation unit 18 . To this end, the temperature sensor 16 is electrically coupled to the SOC estimation unit 18 so as to be able to send and receive electrical signals. The temperature sensor 16 may repeatedly measure the temperature of the secondary battery cell 20 at regular intervals under the control of the SOC estimation unit 18 and output a signal indicating the magnitude of the measured temperature to the SOC estimation unit 18 . have. The SOC estimation unit 18 may determine the temperature of the secondary battery cell 20 according to a signal output from the temperature sensor 16 and store the determined temperature value by itself or in the storage unit 120 of the BMS 10 . .

The temperature sensor 16 may be configured as a thermocouple commonly used in the art. Since the circuit configuration of the temperature sensor 16 for measuring the temperature of the secondary battery cell is obvious to those skilled in the art, a detailed description thereof will be omitted.

The SOC estimation unit 18 performs SOC estimation for the secondary battery cell 20 . The SOC estimating unit 18 accumulates the charging current or the discharging current of the secondary battery cell 20 stored in the storage unit 120 of the BMS 10 or self-stored while the secondary battery cell 20 is being charged or discharged, and the secondary battery cell 20 is charged or discharged. The SOC of the battery cell 20 may be measured.

The initial value of the SOC may be generally determined by measuring the open circuit voltage of the secondary battery cell 20 before charging or discharging of the secondary battery cell starts, and referring to a lookup table in which the SOC is defined for each open circuit voltage.

According to an embodiment, the SOC estimation unit 18 may calculate the SOC of the secondary battery cell 20 using an extended Kalman filter. The extended Kalman filter refers to a mathematical algorithm for adaptively estimating the state of charge of a battery cell by using the voltage, current, and temperature of the battery cell.

Estimation of the state of charge using the extended Kalman filter is, as an example, Gregory L. Plett's paper "Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs Parts 1, 2 and 3" (Journal of Power Source 134, 2004, 252-261) may be referred to, and the above papers may be incorporated as a part of this specification.

The SOC of the secondary battery cell 20 can be determined by other known methods that can estimate the state of charge by selectively utilizing the voltage, temperature, and current of the secondary battery cell 20 in addition to the above-described current integration method or the extended Kalman filter. have.

The calculated SOC value may be stored in the SOC estimation unit 18 or may be stored in the storage unit 120 included in the BMS 10 .

The charging unit 30 may generally control charging and discharging of the secondary battery cell 20 with reference to the SOC value stored in the SOC estimation unit 18 or the storage unit 120 of the BMS 10 . For example, the charging unit 30 may control the charging output or the discharging output of the secondary battery cell 20 by referring to a lookup table in which the output is defined according to the SOC. Also, the charging unit 30 may end charging when the SOC of the secondary battery cell 20 reaches 100%, and stop discharging when the SOC reaches 0%. Of course, the SOC % at which charging and discharging are terminated may be set lower than 100% and greater than 0%. The lookup table may be stored in advance in the SOC estimation unit 18 or the storage unit 120 included in the BMS 10 .

1 , a current source for supplying a charging current to the secondary battery cell 20 and a load to which a discharge current of the secondary battery cell 20 is supplied are not shown.

The current source may be a commercial power source or a generator coupled with an engine of an electric or hybrid vehicle, or a regenerative charging device coupled with a brake. The load is a device that consumes discharge power of the secondary battery cells 20 and may be a power conversion circuit such as a bidirectional inverter coupled to a motor of a vehicle or supplying power required by various electronic devices.

In an embodiment, the above-described SOC estimation unit 18 may be integrated with the control unit 110 of the current sensor error diagnosis apparatus 100 . That is, the control unit 110 may perform the function of the SOC estimation unit 18 described above.

Meanwhile, the current sensor error diagnosis apparatus 100 according to an embodiment of the present invention includes a control unit 110 and a storage unit 120 , and an output unit 130 and a communication unit 140 according to an embodiment. and the like.

The control unit 110 periodically receives current values of the first current sensor 12a and the second current sensor 12b configured to measure a current value of the same current, and uses the received current values to determine the first It is determined whether an error occurs in the current sensor 12a and the second current sensor 12b.

The storage unit 120 receives and stores the determination result of the control unit 110 and the like. The storage unit 120 is not particularly limited in its type as long as it is a storage medium capable of recording and erasing information. For example, the storage unit 120 may be a RAM, a ROM, an EEPROM, a register, a flash memory, a hard disk, an optical recording medium, or a magnetic recording medium.

In addition, the storage unit 120 may be electrically connected to the control unit 110 through a data bus, for example, so that the control unit 110 can access it. Through this connection, the storage unit 120 stores and/or updates and/or erases a program including various control logic executed by the control unit 110, and/or data generated when the control logic is executed. / or can be transmitted. The storage unit 120 may be logically divided into two or more, and some or all of them may be included in the control unit 110 .

The output unit 130 outputs visual information according to the control signal of the control unit 110 . The output unit 130 may be electrically connected to the control unit 110 to receive a control signal from the control unit 110 . The output unit 130 is not particularly limited in its type as long as it can output visual information. For example, the output unit 130 is composed of an LED (Light-Emitting Diode) that outputs an optical signal, or an LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode), or AMOLED (Active Matrix Organic Light-) that displays an image. It may be composed of a display unit including an emitting diode).

The communication unit 140 performs wired communication or wireless communication with an external communication device according to a control signal of the control unit 110 . The communication unit 140 receives the control signal and transmission data of the control unit 110 and transmits it to an external communication device, or transmits the data received from the external communication device to the control unit 110 with the control unit 110 and can be electrically connected. The communication unit 140 is not particularly limited in its type as long as it can perform data communication with an external communication device.

The communication unit 140 may be configured to include a communication port to which a communication cable terminal of an external communication device is connected, a communication interface, and the like. In addition, the communication unit 140 is a near field communication (NFC) communication module or a radio frequency identification (RFID) communication module to transmit data of the control unit 110 or the storage unit 120 to an external communication device by a tag method. or a Bluetooth communication module, a WiFi communication module, or a ZigBee communication module to perform wireless data communication with a peripheral communication device.

As mentioned above, the control unit 110 periodically receives the current values of the first current sensor 12a and the second current sensor 12b configured to measure the current value of the same current, and sets the received current values. It is determined whether an error occurs in the first current sensor 12a and the second current sensor 12b using the

2 is a block diagram showing an example of a control unit 110 applied to the present invention.

Referring to FIG. 2 , the control unit 110 includes a current value sampling unit 111 , a first determination unit 112 , a frequency calculation unit 113 , and a second determination unit 114 , and according to an embodiment, It may further include an error information processing unit 115 and the like.

The components illustrated in FIG. 2 may be components constituting a program module executed by the control unit 110 . The program module may be pre-recorded in the storage unit 120 and then executed by the control unit 110 . One component may be integrated with another component. Also, one component may be divided into two or more sub-components. Data generated by one component may be stored in the storage unit 120 and then referenced by another component, even if not otherwise stated.

The current value sampling unit 111 may include a first current value measured through the first current sensor 12a and a second current value measured through the second current sensor 12b at each of a plurality of preset sampling times. is sampled at the same timing, and the first current value and the second current value sampled at the same timing are transmitted to the first determination unit 112 . In an embodiment of the present invention, the number of sampling times of the first and second current values may be preset to N times. The first determination unit 112 determines whether the magnitude of the difference between the two current values exceeds a predetermined reference value each time the first current value and the second current value sampled at the same timing are received. In this case, the first determination unit 112 may determine whether the magnitude of the difference between the first current value and the second current value sampled at the same timing exceeds a predetermined reference value, for example, 17 [A]. Since the reference value is an example, it may be freely changed to another value.

The first determination unit 112 is, as shown in Equation 1 below, when the magnitude of the difference between the first current value and the second current value does not exceed the reference value 17 [A], the first current sensor 12a and It may be determined that the second current sensor 12b is in a normal state.

[Equation 1]

｜First Current Value - Second Current Value｜ ≤ 17 [A]

On the other hand, the first determination unit 112, as shown in Equation 2 below, when the magnitude of the difference between the first current value and the second current value exceeds the reference value 17 [A], the first determination unit 112 is provisionally As a result, it may be determined that at least one of the first current sensor 12a and the second current sensor 12b is in an error state.

[Equation 2]

｜First current value - second current value｜ > 17 [A]

Preferably, the first determination unit 112 transmits the error occurrence determination result of the current sensor to the frequency calculation unit 113 over N times.

In FIG. 3 , ranges of current values determined as a normal state and an error state when a provisional error is determined according to a current difference value between two current sensors are shown in a rectangular coordinate system.

In the Cartesian coordinate system of FIG. 3 , the X-axis represents the first current value, and the Y-axis represents the second current value. A positive value is assigned to a current value measured when the secondary battery cell 20 is being charged, and a negative value is assigned to a current value measured when the secondary battery cell 20 is being discharged.

Referring to FIG. 3 , when the magnitude of the difference between the first current value and the second current value does not exceed the reference value 17 [A], that is, the first current value and the second current value sampled at the same timing are X and When the point serving as the Y coordinate belongs to the region D1 between the dotted line L1 and the dotted line L2, it may be tentatively determined that the first current sensor 12a and the second current sensor 12b are in a normal state.

From a theoretical point of view, since the first current sensor 12a and the second current sensor 12b measure the same current, the points representing the first current value and the second current value should be located on a straight line with a slope of 1. It can be judged to be in a normal state. However, if points corresponding to the first current value and the second current value belong to the D1 region in consideration of the allowable error of the current sensors, the corresponding current sensors 12a and 12b may be determined to be in a normal state.

On the other hand, the first determination unit 112, when the magnitude of the difference between the first current value and the second current value exceeds the reference value 17 [A], that is, points corresponding to the first current value and the second current value are indicated by a dotted line When it belongs to the region D2 outside the L1 and the dotted line L2, it may be tentatively determined that at least one of the first current sensor 12a and the second current sensor 12b is in an error state.

Referring back to FIG. 2 , the frequency calculation unit 113 sequentially receives the determination results of the first determination unit 112 N times, and the magnitude of the difference between the first voltage value and the second voltage value exceeds the reference value. A first frequency is calculated by accumulating the number of times determined not to have been performed, and a second frequency is calculated by accumulating the number of times it is determined that the difference value exceeds a reference value. In this case, the first frequency may mean a frequency that is tentatively determined to be a normal state, and the second frequency can be considered to mean a frequency that is temporarily determined to be an error state. When the integration of the first frequency and the second frequency over N times is completed, the frequency calculating unit 113 transmits the first frequency and the second frequency to the second determining unit 114 .

The second determination unit 114, when receiving the first frequency and the second frequency from the first determination unit 112, receives the first frequency and the second frequency from the first determination unit 112, the first frequency and An error determination ratio corresponding to the ratio of the first frequency to the sum of the second frequencies is calculated, and the calculated error determination ratio is compared with a predetermined reference ratio to determine whether an error occurs in the current sensor.

The second determination unit 114 may calculate the error determination ratio R as shown in Equation 3 below.

[Equation 3]

R = [first frequency / (first frequency + second frequency)] × 100 [%]

The second determination unit 112 determines that an error does not occur in the first current sensor 12a and the second current sensor 12b when the error determination ratio R is equal to or greater than the reference ratio. On the other hand, when the error determination ratio R is less than the reference ratio, the second determination unit 114 determines that an error has occurred in at least one of the first current sensor 12a and the second current sensor 12b. For example, the second determination unit 114 determines that an error does not occur in the first current sensor 12a and the second current sensor 12b when the error determination ratio R is greater than or equal to 95% of the reference ratio, and the reference ratio If it is less than 95%, it may be determined that an error has occurred in at least one of the first current sensor 12a and the second current sensor 12b. Preferably, the second determination unit 114 transmits error determination information about the current sensor to the error information processing unit 115 .

The error information processing unit 115, when the error determination information received from the second determination unit 114 indicates that an error has occurred in the current sensor, generates a DTC (Diagnostic Trouble Code) indicating the current sensor error and stores the unit It is stored in (120). DTC represents each system error with a unique code. The DTC stored in the storage unit 120 may be transmitted to an external device through the communication unit 140 .

That is, the error information processing unit 115 generates a DTC indicating the current sensor error and stores it in the storage unit 120 , and externally transmits error information indicating the occurrence of the current sensor error through the communication unit 140 together with the DTC. can be sent to the device. In this case, the external device may be a device that reads a diagnosis result of a current sensor, or an ECU that overall manages the operation of a battery device of the vehicle when the secondary battery cell 20 is mounted in an electric vehicle or a hybrid vehicle.

In an embodiment, the error information processing unit 115 may output error information informing that a current sensor error has occurred as visual information through the output unit 130 . In this case, the output unit 130 may light an LED or output an error occurrence notification message through the display unit.

In addition, when the error determination information received from the second determination unit 114 indicates that an error has occurred in the current sensor, the error information processing unit 115 may request the SOC estimation unit 18 to stop the SOC estimation. . The SOC estimation unit 18 receiving the stop request may stop the SOC estimation and transmit a stop completion signal to the control unit 110 or to the upper control system of the BMS 10 through a communication interface.

Meanwhile, the frequency calculation unit 113 transmits the first frequency and the second frequency accumulated over N times to the second determination unit 114 , and then resets the first frequency and the second frequency to 0 . In addition, the current value sampling unit 111 resumes sampling the current values for the first current sensor 12a and the second current sensor 12b when the next periodic diagnosis time comes.

4 is a flowchart illustrating a method for diagnosing a current sensor error according to an embodiment of the present invention. Hereinafter, operations performed by the current sensor error diagnosis apparatus 100 will be described in time series with reference to FIG. 4 .

Referring to FIG. 4 , the control unit 110 of the current sensor error diagnosis apparatus 100 sets current values of the first current sensor 12a and the second current sensor 12b configured to measure the current value of the same current. It is received at every point in time, and it is determined whether an error occurs in the first current sensor 12a and the second current sensor 12b using the received current values.

The control unit 110 may set the sampling number n to 1 as an initial value before the start of sampling the current value, and set the first frequency and the second frequency to 0, respectively.

The current value sampling unit 111 of the control unit 110, for each of a plurality of predetermined sampling time points tn, the first current value I1n and the second current measured by the first current sensor 12a The second current value I2n measured by the sensor 12b is sampled at the same timing, and the first current value and the second current values I1n and I2n sampled at the same timing are used by the first determination unit 112 . It transmits (S410).

Then, the first determination unit 112 of the control unit 110, with respect to the first current value and the second current value sampled at the same timing, the difference value between the two current values, |I1n - I2n| It is determined whether a predetermined reference value, for example, 17 [A] has been exceeded (S420).

When the magnitude of the difference value |I1n - I2n| between the first current value and the second current value does not exceed the reference value 17[A], the first determination unit 112 of the control unit 110 temporarily transmits the first current sensor It is determined that (12a) and the second current sensor 12b are in a normal state, and the determination result is transmitted to the frequency calculation unit 113 .

Then, the frequency calculation unit 113 of the control unit 110 accumulates the first frequency by adding 1 to the first frequency indicating the number of times determined to be in the normal state, and stores it in the storage unit 120 (S430) ).

On the other hand, when the magnitude of the difference between the first current value and the second current value |I1n - I2n| exceeds the reference value 17[A], the first determination unit 112 of the control unit 110 temporarily controls the first current It is determined that at least one of the sensor 12a and the second current sensor 12b is in an error state, and the determination result is transmitted to the frequency calculator 113 .

Then, the frequency calculating unit 113 of the control unit 110 adds 1 to the second frequency indicating the number of times determined to be an error state, and cumulatively calculates the second frequency and stores it in the storage unit 120 (S440) ).

The control unit 110 repeats the above-described processes (S410 to S440) for a predetermined number of sampling times (N) (S450 and S455).

When the first frequency and the second frequency are cumulatively calculated for the error diagnosis result of the current sensor over N times, the frequency calculating unit 113 calculates the accumulated first and second frequencies as the second frequency of the control unit 110 . It is transmitted to the determination unit 114 .

The second determination unit 114 of the control unit 110 calculates an error determination ratio R corresponding to the ratio of the first frequency to the sum of the first frequency and the second frequency as in Equation 3 above, (S460), it is determined whether an error occurs in the current sensor by comparing the calculated error determination ratio R with a predetermined reference ratio, for example, 95% (S470).

When the calculated error determination ratio R is greater than or equal to 95% of the reference ratio, the second determination unit 112 finally determines that no errors have occurred in the first current sensor 12a and the second current sensor 12b. Also, when the next predetermined diagnosis cycle arrives, the control unit 110 may repeat the above-described processes ( S400 to S470 ) ( S480 ). The frequency calculating unit 113 of the control unit 110 resets the first and second frequencies to 0 after transmitting the first and second frequencies accumulated over N times to the second determining unit 114 . do. The current value sampling unit 111 of the control unit 110 resumes sampling the current values for the first current sensor 12a and the second current sensor 12b when the next predetermined diagnosis time arrives.

On the other hand, when the calculated error determination ratio R is less than 95% of the reference ratio, the second determination unit 112 finally has an error in any one of the first current sensor 12a and the second current sensor 12b. It is determined that it has occurred, and the error diagnosis information of the current sensor is transmitted to the error information processing unit 115 .

Then, the error information processing unit 115 of the control unit 110 generates a DTC (Diagnostic Trouble Code) indicating the current sensor error and stores it in the storage unit 120 (S490).

Optionally, the error information processing unit 115 generates and stores the DTC indicating the current sensor error in the storage unit 120, and then transmits the error information indicating the fact that the current sensor error has occurred to the communication unit 140 together with the DTC. can be transmitted to an external device.

In an embodiment, the error information processing unit 115 may output error information informing that a current sensor error has occurred as visual information through the output unit 130 . In this case, the output unit 130 may light an LED or output an error occurrence notification message through the display unit.

In addition, the error information processing unit 115 may request the SOC estimation unit 18 to stop estimating the SOC when the error diagnosis information of the current sensor transmitted from the second determination unit 114 indicates that an error has occurred in the current sensor. have. The SOC estimation unit 18 receiving the stop request may stop the SOC estimation and transmit a stop completion signal to the control unit 110 or to the upper control system of the BMS 10 through a communication interface.

In the present invention, the control unit 110 is a processor, application-specific integrated circuit (ASIC), other chipsets, logic circuits, registers, communication modems, data processing devices, etc. known in the art to execute the various control logics described above. may optionally be included. In addition, when the control logic is implemented in software, the control unit 110 may be implemented as a set of program modules. In this case, the program module may be stored in the memory and executed by the processor. The memory may be internal or external to the processor, and may be connected to the processor by various well-known computer components. In addition, the memory may be included in the storage unit 120 of the present invention. In addition, the memory is a generic term for devices in which information is stored regardless of the type of device, and does not refer to a specific memory device.

In addition, at least one or more of the various control logics of the control unit 110 may be combined, and the combined control logics may be written in a computer-readable code system and recorded in a computer-readable recording medium. The type of the recording medium is not particularly limited as long as it can be accessed by a processor included in the computer. As an example, the recording medium includes at least one selected from the group consisting of ROM, RAM, EEPROM, registers, flash memory, CD-ROM, magnetic tape, hard disk, floppy disk, and an optical data recording device. In addition, the code system may be distributed, stored, and executed in computers connected to a network. In addition, functional programs, codes, and code segments for implementing the combined control logics can be easily inferred by programmers in the art to which the present invention pertains.

In the present invention, a secondary battery cell may indicate one unit cell, or may indicate an aggregate of unit cells in which a plurality of unit cells are connected in series and/or in parallel. An assembly of unit cells may be referred to as a battery module or a battery pack, and the present invention is not limited by the number and connection method of the unit cells.

As described above, according to the present invention, by diagnosing the errors of the current sensors using only the current values of the two current sensors, the current in the same way regardless of the type of system using the current sensor, the type of current source, or voltage characteristics, etc. The error of the sensor can be diagnosed, and in particular, it can be easily applied to various systems including two current sensors. The system can determine the average value of the current values measured through the two current sensors as the current measurement value, and at the same time can reliably diagnose the error of the current sensor.

In addition, the present invention compares the current values measured by the two current sensors at the same time to determine whether an error occurs in the current sensor, so that an error in case the current sensor does not work at all, as well as a decrease in response speed or phase delay of the current sensor, etc. Accordingly, errors in the case of measurement errors occurring in the current value can also be accurately diagnosed.

In addition, the present invention repeatedly determines whether an error occurs in the current sensor based on the difference between the current values actually measured by the two current sensors, accumulates the determination results, and calculates the frequency for each determination result through the accumulated determination results. Then, by probabilistically determining whether or not a final error occurs again through the frequency of each determination result, it has a strong characteristic against instantaneous current change or frequency change, and the accuracy and reliability of error diagnosis can be improved.

In addition, the present invention can fundamentally prevent a phenomenon in which a difference is generated between measured current values according to a cutoff frequency difference between current sensors when a high-frequency current is input, so that the current sensor is misdiagnosed as an error.

It goes without saying that the embodiments according to the present invention can solve various technical problems other than those mentioned herein in the related technical field as well as the related technical field.

In describing various embodiments of the present invention, components named '~ unit' or '~ unit' should be understood as functionally distinct elements rather than physically distinct elements. Accordingly, each component may be selectively integrated with other components or each component may be divided into sub-components for efficient execution of control logic(s). It is apparent to those skilled in the art that even if the components are integrated or divided, if the same function can be recognized, the integrated or divided components should also be interpreted as being within the scope of the present invention.

In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the scope of equivalents of the claims.

100: current sensor error diagnosis device 110: control unit
111: current value sampling unit 112: first determination unit
113: frequency calculation unit 114: second determination unit
115: error information processing unit 120: storage unit
130: output unit 140: communication unit

Claims (15)

In the current sensor error diagnosis apparatus for diagnosing errors of a plurality of current sensors,
a control unit configured to receive current values of a first current sensor and a second current sensor configured to measure a current value of the same current, and determine whether an error occurs in the first current sensor and the second current sensor; and
a storage unit for receiving and storing the determination result of the control unit;
The control unit is
a current value sampling unit for sampling a first current value measured by the first current sensor and a second current value measured by the second current sensor at the same timing at each predetermined sampling time;
a first determination unit for determining whether a difference value between two current values exceeds a predetermined reference value for each of a plurality of first and second current values sampled at the same timing;
A first frequency is calculated by accumulating the number of times it is determined that the magnitude of the difference value does not exceed the reference value, and calculating a second frequency by accumulating the number of times it is determined that the magnitude of the difference value exceeds the reference value. wealth; and
A second method for calculating an error determination ratio corresponding to a ratio of the first frequency to the sum of the first and second frequencies, and comparing the calculated error determination ratio with a predetermined reference ratio to determine whether an error has occurred including a judging unit;
The second determination unit, when the calculated error determination ratio is equal to or greater than the reference ratio, determines that no errors have occurred in the first current sensor and the second current sensor, and when the calculated error determination ratio is less than the reference ratio Current sensor error diagnosis apparatus, characterized in that configured to determine that an error has occurred in at least one of the first current sensor and the second current sensor.
delete According to claim 1,
The frequency calculation unit is configured to reset the first frequency and the second frequency to 0 after the second determination unit determines that an error does not occur in the first current sensor and the second current sensor,
and the current value sampling unit is configured to resume sampling the current values for the first current sensor and the second current sensor when a next predetermined diagnosis time arrives.
According to claim 1,
The control unit, when the second determination unit determines that an error has occurred in at least one of the first current sensor and the second current sensor, generates a DTC (Diagnostic Trouble Code) indicating a current sensor error and sends it to the storage unit. Current sensor error diagnosis apparatus, characterized in that it further comprises an error information processing unit to store.
5. The method of claim 4,
The device further comprises an output unit for outputting visual information,
The error information processing unit may include, when the second determination unit determines that an error has occurred in at least one of the first current sensor and the second current sensor, transmits error information notifying the occurrence of a current sensor error as visual information through the output unit Current sensor error diagnosis device, characterized in that configured to output as.
5. The method of claim 4,
The device further comprises a communication unit for performing wired communication or wireless communication,
The error information processing unit, when the second determination unit determines that an error has occurred in at least one of the first current sensor and the second current sensor, transmits error information informing that a current sensor error has occurred to another device through the communication unit Current sensor error diagnosis device, characterized in that configured to transmit to.
A battery management system comprising the device for diagnosing a current sensor error according to claim 1 .
8. The method of claim 7,
When the second determination unit determines that an error occurs in at least one of the first current sensor and the second current sensor, the control unit measures a current value through the first current sensor or the second current sensor, The battery management system according to claim 1, further comprising an error information processing unit requesting to stop estimating the SOC as an SOC estimating unit for estimating a state of charge (SOC) of the secondary battery cell.
In the method for diagnosing errors of a plurality of current sensors configured to measure the current of the same secondary battery cell by a processor of a Battery Management System (BMS),
(a) at each predetermined sampling time point, a first current value measured by a first current sensor among the plurality of current sensors and a second current value measured by a second current sensor among the plurality of current sensors are identical sampling in timing;
(b) determining whether the magnitude of the difference between the two current values exceeds a predetermined reference value for each of the plurality of first and second current values sampled at the same timing;
(c) calculating the first frequency by accumulating the number of times it is determined that the magnitude of the difference value exceeds the reference value, and calculating the second frequency by accumulating the number of times it is determined that the magnitude of the difference value does not exceed the reference value to do; and
(d) calculating an error determination ratio corresponding to the ratio of the first frequency to the sum of the first and second frequencies, and comparing the calculated ratio with a predetermined reference ratio to determine whether an error occurs including,
In step (d), when the calculated error determination ratio is equal to or greater than the reference ratio, it is determined that no errors have occurred in the first current sensor and the second current sensor, and the calculated error determination ratio is less than the reference ratio. and determining that an error has occurred in at least one of the first current sensor and the second current sensor.
delete 10. The method of claim 9,
After determining that no errors have occurred in the first current sensor and the second current sensor in step (d), the first frequency and the second frequency are reset to 0, and when the next predetermined diagnosis time arrives, the A method for diagnosing a current sensor error, comprising repeating steps (a) to (d).
10. The method of claim 9,
(e) when it is determined that an error has occurred in at least one of the first current sensor and the second current sensor in step (d), a DTC (Diagnostic Trouble Code) indicating the current sensor error is generated and the storage unit of the BMS Current sensor error diagnosis method, characterized in that it further comprises the step of storing in.
10. The method of claim 9,
(f) when it is determined that an error has occurred in at least one of the first current sensor and the second current sensor in step (d), error information informing that the current sensor error has occurred is displayed as visual information through the output unit of the BMS Current sensor error diagnosis method, characterized in that it further comprises the step of outputting.
10. The method of claim 9,
(g) when it is determined in step (d) that an error has occurred in at least one of the first current sensor and the second current sensor, error information informing that the current sensor error has occurred is transmitted to another device through the communication unit of the BMS Current sensor error diagnosis method, characterized in that it further comprises the step of transmitting to.
10. The method of claim 9,
(h) when it is determined in step (d) that an error has occurred in at least one of the first current sensor and the second current sensor, the secondary battery using the current value of the first current sensor or the second current sensor The method for diagnosing a current sensor error according to claim 1, further comprising the step of requesting to stop estimating the SOC to the SOC estimating unit of the BMS for estimating the state of charge (SOC) of the cell.

Images