Vehicle control system
A control device employing a battery voltage sensor and periodic updates addresses the inaccuracies of current sensors, ensuring accurate charging determination and preventing charge loss in vehicles with external power sources.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-01-11
- Publication Date
- 2026-05-19
AI Technical Summary
Existing battery current sensors in vehicles with rechargeable batteries powered by external power sources have large errors, making it difficult to accurately determine whether charging is occurring normally, leading to potential misjudgments about the state of charge (SOC) and unnecessary charging stoppages.
A control device using a battery voltage sensor to detect and store the starting voltage during charging, updating it at predetermined intervals, and stopping charging if the detected voltage drops below a predetermined value, while using machine learning for processing to ensure accurate determination of normal charging.
Accurately determines whether charging is proceeding normally, preventing unnecessary charge decreases and misjudgments, even during low-power charging, by utilizing a battery voltage sensor and periodic updates to the starting voltage.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a control device applied to a vehicle equipped with a rechargeable battery powered by an external power source.
Background Art
[0002] Patent Document 1 discloses a device for calculating the state of charge (SOC) of a battery. In this calculation device, the state of charge is calculated using a current sensor that detects the charge and discharge current of the battery and a voltage sensor that detects the voltage between the terminals of the battery.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a vehicle equipped with a rechargeable battery powered by an external power source, it is required to accurately determine during charging that the charging of the battery is being performed normally. Here, the battery current sensor used to detect the charge and discharge current of the battery generally has a large error and is not suitable for determining whether charging is being performed normally.
[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a control device for a vehicle that can accurately determine whether charging is being performed normally by using a battery voltage sensor.
Means for Solving the Problems
[0006] The vehicle control device described herein is applicable to a vehicle equipped with a battery that can be charged by power from an external power source. The control device comprises a battery voltage sensor for detecting the battery voltage of the battery, a processor, and a memory device. The processor stores the detected battery voltage value, which is detected by the battery voltage sensor at the start of charging from the external power source, as the starting voltage in the memory device. If the detected battery voltage value acquired at predetermined intervals after the start of charging is higher than the current starting voltage, the processor updates the starting voltage with the detected value and stores the updated starting voltage in the memory device. The processor then stops charging if the detected battery voltage value acquired at predetermined intervals is lower than the current starting voltage by a predetermined value or more. In addition, machine learning may be used for processing by the control device described herein. [Effects of the Invention]
[0007] According to this disclosure, it will be possible to accurately determine whether charging is proceeding normally by using a battery voltage sensor. [Brief explanation of the drawing]
[0008] [Figure 1] This diagram schematically shows an example of the configuration of a vehicle to which the control device according to the embodiment is applied. [Figure 2] This diagram illustrates the processing flow during charging according to the embodiment. [Figure 3] This is a time chart showing an example of the operations associated with the charging process according to the embodiment. [Modes for carrying out the invention]
[0009] Embodiments of this disclosure will be described with reference to the attached drawings.
[0010] 1. Vehicle configuration Figure 1 is a schematic diagram showing an example of the configuration of a vehicle 1 to which the control device according to the embodiment is applied. Vehicle 1 is a vehicle that can be charged by power from an external power source. For example, vehicle 1 is a battery electric vehicle (BEV). Alternatively, vehicle 1 may be a plug-in hybrid electric vehicle (PHEV).
[0011] Vehicle 1 is equipped with a drive system 10 that drives the wheels 2. The drive system 10 comprises an electric motor 12, an inverter 14, a storage battery 16, a DC / DC converter 18, a system main relay (SMR) 20, an AC charger 22, a charging relay (CHR) 24, and an electronic control unit (ECU) 30.
[0012] The electric motor 12 is configured, for example, as a synchronous regenerative motor and is connected to the wheel 2. The inverter 14 is used to drive the electric motor 12 and is connected to the first power line 26. The rotation of the electric motor 12 is controlled by the inverter 14, which is controlled according to commands from the ECU 30.
[0013] The battery 16 is, for example, a lithium-ion battery or a nickel-metal hydride battery and is connected to the first power line 26. The DC / DC converter 18 is connected to the first power line 26 and the second power line 28. The DC / DC converter 18 is controlled by the ECU 30 to step down the voltage of the first power line 26 and supply it to the second power line 28. The SMR 20 is installed between the battery 16 and the inverter 14 and the DC / DC converter 18 in the first power line 26. The SMR 20 is controlled by the ECU 30 to connect and disconnect the battery 16 and the inverter 14 and the DC / DC converter 18.
[0014] When connected to an external power source (AC power source), the AC charger 22 charges the battery 16 using power from the external power source. The AC charger 22 is connected, for example, to the inverter 14 and DC / DC converter 18 and the SMR 20 in the first power line 26 via the CHR 24.
[0015] The ECU 30 is a computer that controls the drive system 10 and corresponds to an example of a "vehicle control device" according to this disclosure. The ECU 30 includes a processor 32 and a storage device 34. The processor 32 performs various processes. These processes include, for example, the charging process of the battery 16, which will be described later. The storage device 34 stores various information necessary for the processing by the processor 32. The various processes performed by the ECU 30 are realized when the processor 32 executes a computer program. The computer program is stored in the storage device 34. Alternatively, the computer program may be recorded on a computer-readable recording medium. Furthermore, the various processes performed by the processor may be realized by hardware processing using dedicated electronic circuits. The ECU 30 may be configured by combining multiple ECUs. Also, some of the charging processes described later may be performed by an external system to the vehicle 1, such as a cloud server.
[0016] The ECU 30 receives signals from the battery sensor 36. The battery sensor 36 is a set of sensors that detect the state of the storage battery 16. Specifically, the battery sensor 36 includes, for example, a battery voltage sensor and a battery current sensor. The battery voltage sensor detects the battery voltage of the storage battery 16 (more specifically, the terminal voltage). The battery current sensor detects the current (battery current) flowing through the storage battery 16.
[0017] Vehicle 1 is equipped with auxiliary equipment (power-consuming devices) 38. Auxiliary equipment 38 is connected to the second power line 28. More specifically, auxiliary equipment 38 is connected to the DC / DC converter 18 via, for example, an auxiliary battery (not shown). Therefore, auxiliary equipment 38 can be operated by power from the storage battery 16. Also, when My Room mode, which is an example of operation mode M described later, is selected, auxiliary equipment 38 can also be operated by power supplied from an external power source via the storage battery 16. Auxiliary equipment 38 is, for example, a power supply device (e.g., AC 100V power supply) for supplying power to various electrical components such as air conditioning and audio equipment, and / or appliances such as home appliances.
[0018] 2. Processing during charging During battery charging (e.g., AC charging), it is necessary to be able to accurately determine whether the charging is proceeding normally. However, battery current sensors used to detect the battery current (charge / discharge current) generally have large errors and are not suitable for determining whether charging is proceeding normally. Therefore, it is desirable to be able to accurately determine whether charging is proceeding normally using a battery voltage sensor that detects the battery voltage (terminal voltage) VB of the battery.
[0019] More specifically, when using a battery current sensor to determine if charging is proceeding normally, especially during low-power charging such as 100V-6A, the presence of detection errors in the battery current sensor can lead to the following problems: Specifically, the system may incorrectly determine that charging is occurring when the battery is actually discharging, causing the battery's State of Charge (SOC) to decrease. To avoid this problem, one could consider employing a logic that stops charging when an extremely low power output (e.g., 250W or less) is detected, making it impossible to determine whether charging or discharging is occurring due to the battery current sensor's errors. However, in configurations where the charger is located directly below the SMR, as in the example drive system 10 shown in Figure 1, resulting in high power consumption of auxiliary equipment during charging, the above logic could lead to frequent charging stoppages.
[0020] In view of the above problems, in order to accurately determine whether charging is being performed normally by using a battery voltage sensor, in the present embodiment, when AC charging (AC charging) using an AC charger 22 is performed, the following processing is executed by an ECU 30.
[0021] That is, the ECU 30 (processor 32) stores, as a starting voltage, the detected value of the voltage (battery voltage VB) detected by the battery voltage sensor (battery sensor 36) at the start of AC charging in the storage device 34. Then, after the start of the AC charging, the ECU 30 acquires the detected value of the battery voltage VB every predetermined period T.
[0022] As an example, the predetermined period T corresponds to the execution cycle of the offset learning (zero-point learning) of the battery current sensor repeatedly executed during AC charging. In the offset learning, the process of learning the zero point of the battery current sensor is executed while temporarily stopping the AC charging. Note that the specific process of the offset learning is known as described in, for example, Japanese Patent Laid-Open No. 2012-217234, and thus a detailed description thereof is omitted.
[0023] Each time a predetermined period T elapses after the start of AC charging, the ECU 30 determines whether the detected value of the battery voltage VB is higher than the current value of the starting voltage. As a result, when the detected value is higher than the current value of the starting voltage, the ECU 30 updates the starting voltage with the detected value and stores the updated starting voltage in the storage device 34. On the other hand, when the detected value is lower than the current value of the starting voltage by a predetermined value ΔVB or more, the ECU 30 stops the AC charging.
[0024] Furthermore, if operation mode M is selected during AC charging, the ECU 30 continues AC charging while erasing the starting voltage stored in the memory device 34. Operation mode M refers to a mode in which a decrease in the state of charge (SOC) of the storage battery 16 is expected during charging. The My Room mode provided by the vehicle 1 is an example of operation mode M. My Room mode is a mode in which the auxiliary equipment 38 is operated by power supplied from an external power source via the storage battery 16 while AC charging continues. Operation modes M, such as My Room mode, are selected and executed, for example, by the user of the vehicle 1 through the operation of HMI (Human Machine Interface) equipment (not shown).
[0025] Next, the charging process will be explained in more detail with reference to Figures 2 and 3. Figure 2 is a diagram showing the flow of the charging process according to the embodiment. Figure 3 is a time chart showing an example of the operations associated with the charging process according to the embodiment.
[0026] In Figure 2, AC charging is started in step S100 (time t0 in Figure 3). Once AC charging starts, in step S102, the ECU 30 stores the detected battery voltage VB at the start of AC charging in the memory device 34 as the starting voltage. More specifically, as shown in Figure 3, the ECU 30 acquires the detected battery voltage VB at the first offset learning execution timing that occurs immediately after the start of AC charging (time t1 in Figure 3), and stores the acquired detected value in the memory device 34 as the starting voltage.
[0027] Subsequently, the ECU 30 acquires the detected value of the battery voltage VB at predetermined intervals T (i.e., each time the offset learning execution cycle arrives) and compares the acquired detected value with the current value of the starting voltage (i.e., the latest value stored in the memory device 34). If the acquired detected value of the battery voltage VB is greater than the current value of the starting voltage, the process proceeds to step S104.
[0028] In step S104, the ECU 30 updates the starting voltage based on the acquired detection value and stores the updated starting voltage in the memory device 34. If the starting voltage is updated in this way, and the relationship that the detected value is greater than the current starting voltage is satisfied after the next predetermined period T has elapsed, the process proceeds to step S106. As a result, the starting voltage is updated with the newly acquired detection value. More specifically, if the above relationship is satisfied each time the predetermined period T has elapsed, the process in step S106 is repeatedly executed. Figure 3 shows an example in which the battery voltage VB increases at each of the three offset learning timings that occur after the start of storing the starting voltage, and the starting voltage is updated accordingly. The predetermined period T is, for example, 30 minutes. Also, as the battery voltage VB increases, the remaining charge of the storage battery 16 increases.
[0029] On the other hand, if My Room mode (operating mode M) is selected and started during AC charging (for example, at time t2 in Figure 3), the process proceeds to step S108. In step S108d, the ECU 30 continues AC charging while erasing the starting voltage stored in the memory device 34. Additionally, if the power consumed by the auxiliary equipment 38 is greater than the power supplied to the battery 16 from the external power source (charging power) during My Room mode, the battery voltage VB will decrease as shown in Figure 3, and consequently, the remaining charge (SOC) of the battery 16 will decrease. Thus, when My Room mode is selected, a decrease in the remaining charge of the battery 16 is expected during AC operation (in other words, a decrease in the remaining charge is acceptable).
[0030] When My Room mode is deselected and My Room mode ends during AC charging (for example, at time t3 in Figure 3), the comparison between the detected value and the starting voltage, which is performed during the offset learning execution cycle, is resumed. Specifically, as shown in Figure 3, when the timing for offset learning (time t4 in Figure 3) arrives after the end of My Room mode, the ECU 30 acquires the detected value of the battery voltage VB in step S106 and stores the acquired detected value as the starting voltage in the memory device 34. Figure 3 shows an example in which the battery voltage VB increases and the starting voltage is updated accordingly at each of the three offset learning timings that arrive after the resumption of starting voltage storage at time t4.
[0031] After the processing in step S106, if the relationship that the detected value is greater than the current value of the starting voltage is satisfied each time a predetermined period T has elapsed, the process proceeds to step S110, and the starting voltage is updated with the newly acquired detected value. Furthermore, if this relationship is continuously satisfied, the process in step S110 is repeatedly executed until AC charging is complete. On the other hand, once AC charging is complete (step S112), the process shown in Figure 2 ends.
[0032] Furthermore, if the detected battery voltage VB acquired at the time when the next predetermined period T has elapsed after the processing of step S106 (time t5 in Figure 3) is less than or equal to the current value of the starting voltage, the ECU 30 does not update the starting voltage using the detected value. For this reason, the detected value is not stored in the storage device 34. Also, at time t5, the difference between the current value of the starting voltage (value at time t4) and the detected value at time t5 is less than a predetermined value ΔVB. This predetermined value ΔVB is, for example, the crossover of the battery voltage sensor (for example, 20mV).
[0033] In the example shown in Figure 3, the detected battery voltage VB continues to decrease even after the predetermined period T following time t5 has elapsed to time t6. Furthermore, the difference between the current value of the starting voltage (value at time t4) and the detected value at time t6 is still less than the predetermined value ΔVB.
[0034] On the other hand, at time t7, after the predetermined period T following time t6, the difference between the current value of the starting voltage (the value at time t4) and the detected value at time t7 exceeds the predetermined value ΔVB. That is, at time t7, the detected value of the battery voltage VB is lower than the current value of the starting voltage by the predetermined value ΔVB or more. In this case, the ECU 30 stops AC charging in step S114. Then, the process shown in Figure 2 is completed.
[0035] 3. Effects As explained above, according to the processing of this embodiment, the detected value of the battery voltage VB at the start of AC charging is stored in the storage device 34 as the starting voltage. However, if the starting voltage is fixed at a value determined initially in this way, it would allow the battery 16's state of charge (SOC) to decrease after it has risen. In this regard, according to the processing of this embodiment, if the detected value of the battery voltage VB acquired at predetermined intervals T after the start of AC charging is higher than the current value of the starting voltage, the starting voltage is updated by the detected value, and the updated starting voltage is stored in the storage device 34. As a result, unless the starting voltage is erased by the processing in step S108, the maximum value of the battery voltage VB during the charging trip from the start to the end of AC charging is always set as the starting voltage. Furthermore, if the detected value of the battery voltage VB acquired at predetermined intervals T is lower than the current value of the starting voltage by a predetermined value ΔVB or more, AC charging is stopped. Thus, according to the processing of this embodiment, it is possible to monitor whether the battery voltage VB is continuously rising during AC charging. For this reason, it becomes possible to accurately determine whether AC charging is being performed normally using the battery voltage sensor.
[0036] Furthermore, according to the processing of this embodiment, even if discharge occurs during AC charging due to some abnormality, AC charging can be appropriately stopped, preventing unnecessary decreases in the remaining charge (SOC). Also, since a battery voltage sensor is used instead of a battery current sensor, which has a large sensor error, it becomes possible to appropriately determine when to stop AC charging even during low-power charging.
[0037] Furthermore, according to this embodiment, if an operating mode M is selected during AC charging in which a decrease in the remaining charge (SOC) of the storage battery 16, such as My Room mode, is expected, the starting voltage stored in the storage device 34 is erased while AC charging continues. In this way, by erasing the starting voltage without updating it in situations where a decrease in remaining charge is clear, it is possible to suppress misjudgments regarding whether AC charging is being performed normally. More specifically, in the example shown in Figure 3, if the starting voltage updated and stored immediately before the start of My Room mode at time t2 is not erased and remains, then at time t4 after the end of My Room mode, even though the battery voltage VB has actually increased due to the resumption of AC charging, it will be mistakenly judged that the battery voltage VB has decreased. In contrast, the processing of this embodiment can prevent such misjudgments.
[0038] Furthermore, according to this embodiment, the predetermined period T corresponds to the execution cycle of offset learning of the battery current sensor. This allows the starting voltage to be identified and stored in a stable state where AC charging is temporarily stopped, rather than in a state where the battery voltage VB is unstable due to AC charging. This makes it possible to determine more accurately whether AC charging is being performed normally.
[0039] Furthermore, in this embodiment, the tolerance of the battery voltage sensor is used as a predetermined value ΔVB used to determine whether or not to stop AC charging based on a comparison of the detected battery voltage VB with the starting voltage. This makes it possible to detect the discharge situation more accurately. [Explanation of symbols]
[0040] 1 vehicle, 10 drive systems, 16 batteries, 22 AC chargers, 30 electronic control units (ECUs), 32 processors, 34 memory devices, 36 battery sensors
Claims
1. A control device applicable to a vehicle equipped with a battery that can be charged by power from an external power source, A battery voltage sensor for detecting the battery voltage of the aforementioned storage battery, Processor and Memory device and Equipped with, The aforementioned processor, The detected value of the battery voltage, which is detected by the battery voltage sensor when charging by the external power supply begins, is stored in the storage device as the starting voltage. If the detected battery voltage, acquired at predetermined intervals after the start of charging, is higher than the current starting voltage, the starting voltage is updated using the detected value, and the updated starting voltage is stored in the memory device. If the detected battery voltage, acquired at predetermined intervals, is lower than the current starting voltage by a predetermined value or more, the charging is stopped. The vehicle is equipped with an operating mode in which a decrease in the remaining charge of the storage battery is expected during the execution of the charging, If the operating mode is selected during the execution of the charging, the processor continues the charging while erasing the starting voltage stored in the memory device. Vehicle control system.
2. A control device applicable to a vehicle equipped with a battery that can be charged by power from an external power source, A battery voltage sensor for detecting the battery voltage of the aforementioned storage battery, Processor and Memory device and Equipped with, The aforementioned processor, The detected value of the battery voltage, which is detected by the battery voltage sensor when charging by the external power supply begins, is stored in the storage device as the starting voltage. If the detected battery voltage, acquired at predetermined intervals after the start of charging, is higher than the current starting voltage, the starting voltage is updated using the detected value, and the updated starting voltage is stored in the memory device. If the detected battery voltage, acquired at predetermined intervals, is lower than the current value of the previous starting voltage by a predetermined value or more, the charging is stopped. The vehicle further includes a battery current sensor for detecting the battery current of the storage battery, The predetermined period corresponds to the execution cycle of offset learning, in which the charging is temporarily stopped during the charging process while the zero point of the battery current sensor is learned. Vehicle control system.
3. The vehicle further includes a battery current sensor for detecting the battery current of the storage battery, The predetermined period corresponds to the execution cycle of offset learning, in which the charging is temporarily stopped during the charging process while the zero point of the battery current sensor is learned. A vehicle control device according to claim 1.
4. The aforementioned vehicle is equipped with auxiliary equipment, The aforementioned operating mode is a mode in which the auxiliary equipment is operated by power supplied from the external power source via the storage battery while continuing the charging process. A vehicle control device according to claim 1.
5. The predetermined value is the tolerance of the battery voltage sensor. A vehicle control device according to claim 1.