Charging device

Abstract

The present invention provides a charging device capable of charging with either low voltage or high voltage. [Solution] The charging device A1 charges the battery 91 of an electric vehicle 9 that moves by driving an electric motor with the power of the battery 91. The charging device A1 comprises a power supply unit 2 that outputs power for charging the battery 91, a control unit 4 that controls the power supply unit 2, and a communication unit 3 that communicates with the electric vehicle 9. The control unit 4 includes an adjustment unit 43 that adjusts the charging current and charging voltage output from the power supply unit 2, and a switching unit 42 that switches between a high-voltage mode and a low-voltage mode that charge in different voltage ranges. The adjustment unit 43 temporarily reduces the charging current when switching from the low-voltage mode to the high-voltage mode. The switching unit 42 switches from the low-voltage mode to the high-voltage mode while the charging current is temporarily reduced.

Description

Technical Field

[0001] The present disclosure relates to a charging device for charging a storage battery of an electric moving body.

Background Art

[0002] In recent years, with the spread of electric moving bodies such as electric vehicles, the maintenance of charging devices for charging the storage batteries of electric moving bodies has been progressing. For example, Patent Document 1 discloses an example of a conventional charging device. The charging device (charging system for electric vehicles) described in Patent Document 1 converts AC power from an AC power source into DC power and supplies it to an electric vehicle, thereby charging the in-vehicle storage battery of the electric vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to shorten the charging time of electric vehicles, the charging device is being made to have higher output. In such a charging device with higher output, in order to suppress the charging cable from becoming thick and heavy, the charging voltage output to the storage battery may be increased. On the other hand, there are also electric vehicles that do not support high-voltage charging, and there is a need for a charging device that can perform both charging at a low charging voltage and charging at a high charging voltage.

[0005] The present disclosure has been conceived in view of the above circumstances, and its object is to provide a charging device that can perform either low-voltage or high-voltage charging.

Means for Solving the Problems

[0006] The charging device provided by this disclosure is a charging device for charging a storage battery of an electric mobile body that moves by driving an electric motor with the power of the storage battery, and comprises a power supply unit that outputs power for charging the storage battery, a control unit that controls the power supply unit, and a communication unit that communicates with the electric mobile body, wherein the control unit includes an adjustment unit that adjusts the charging current and charging voltage output from the power supply unit, and a switching unit that switches between a high-voltage mode and a low-voltage mode that charge in different voltage ranges, wherein the adjustment unit temporarily reduces the charging current when switching from the low-voltage mode to the high-voltage mode, and the switching unit switches from the low-voltage mode to the high-voltage mode while the charging current is temporarily reduced.

[0007] In a preferred embodiment of the charging device, the power supply unit includes a low-voltage circuit unit that outputs the charging voltage in the low-voltage mode and a high-voltage circuit unit that outputs the charging voltage in the high-voltage mode, and the adjustment unit switches between a state in which the charging voltage is output from the low-voltage circuit unit and a state in which the charging voltage is output from the high-voltage circuit unit when switching modes.

[0008] In a preferred embodiment of the charging device, the control unit includes a voltage monitoring unit for monitoring the charging voltage, and the switching unit automatically switches to the high-voltage mode when the charging voltage in the low-voltage mode exceeds a predetermined threshold, wherein the threshold is a value within the overlapping range where the voltage range that can be output in the low-voltage mode and the voltage range that can be output in the high-voltage mode overlap.

[0009] In a preferred embodiment of the charging device, the electric mobile body corresponds to the output control function performed by the charging device, the communication unit obtains a minimum charging current value set for the electric mobile body from the electric mobile body, and the adjustment unit reduces the charging current to the minimum charging current value when the mode is switched.

[0010] In a preferred embodiment of the charging device, the adjustment unit releases the reduction in charging current when it switches from the low-voltage mode to the high-voltage mode. [Effects of the Invention]

[0011] In the charging device of this disclosure, the control unit includes an adjustment unit that adjusts the charging current and charging voltage output from the power supply unit, and a switching unit that switches between a high-voltage mode and a low-voltage mode, which charge in different voltage ranges. With this configuration, for electric mobile devices that only support low-voltage charging, charging can be performed in the low-voltage range by setting the low-voltage mode. On the other hand, for electric mobile devices that can be charged at high voltage, charging can be performed in the high-voltage range by setting the high-voltage mode. Therefore, the charging device A1 can charge electric mobile devices at either low voltage or high voltage. [Brief explanation of the drawing]

[0012] [Figure 1] This is an external view showing a charging device according to one embodiment. [Figure 2] This is a functional block diagram showing a charging device according to one embodiment. [Figure 3] This is a flowchart showing the charging control performed by the control unit of a charging device according to one embodiment. [Figure 4] This graph shows the current and voltage changes during mode switching of a charging device according to one embodiment. [Modes for carrying out the invention]

[0013] Preferred embodiments of the charging device of this disclosure will be described below with reference to the drawings. Hereafter, identical or similar components will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0014] Figures 1 and 2 show a charging device A1 according to one embodiment. Figure 1(a) is an external view of the charging device A1 from above, and Figure 1(b) is an external view of the charging device A1 from the side. Figure 2 is a functional block diagram showing the charging device A1. The charging device A1 is equipment for charging an electric vehicle 9. The electric vehicle 9 is an automobile equipped with an electric motor as a power source and a storage battery 91 that supplies power to the electric motor, and includes not only electric vehicles that use only an electric motor as a power source, but also hybrid vehicles that have an internal combustion engine as well. The charging target of the charging device A1 may be not only automobiles, but also other electric mobile devices (for example, turret trucks and electric motorcycles) equipped with an electric motor as a power source and a storage battery that supplies power to the electric motor. The charging device A1 supplies power (hereinafter referred to as "charging power") to the electric vehicle 9 to charge the storage battery 91. The charging device A1 is installed in a parking space P1 such as a parking lot of a facility (for example, a public facility and a commercial facility). Note that the arrangement of the charging device A1 relative to the parking space P1 is not limited to the illustrated example. The charging device A1 is installed on the ground. The parking space P1 is a parking space for the electric vehicle 9.

[0015] As shown in Figures 1 and 2, the charging device A1 comprises a main body 1, a charging cable 6, and a charging connector 7. In this embodiment, the charging device A1 is described as having one set of charging cables 6 and charging connector 7 for one main body 1, but one main body 1 may have multiple sets of charging cables 6 and charging connector 7. In other words, the charging device of this disclosure is not limited to a single-plug type, but may also be a multi-plug type.

[0016] The main unit 1 is connected to the electric vehicle 9 by the charging connector 7 being connected to the plug-in connector 92 of the electric vehicle 9. The main unit 1 supplies charging power to the electric vehicle 9 by outputting a charging current and a charging voltage. This charges the battery 91 of the electric vehicle 9. The charging power is, for example, DC power. The main unit 1 communicates with the electric vehicle 9 connected via the charging cable 6.

[0017] In this embodiment, the main unit 1 (charging device A1) has a dynamic control function, and the electric vehicle 9 corresponds to the dynamic control function. The dynamic control function is a function (output control function) in which the charging device A1 controls the output of charging power, and adjusts the amount of charge to the electric vehicle 9 at the request of the charging device A1. The charging control of the electric vehicle 9 is basically performed as follows: The main unit 1 transmits an outputtable current value to the connected electric vehicle 9. The outputtable current value is the current value that can be output from the charging device A1 to the electric vehicle 9. The electric vehicle 9 generates a charging current command value within the range of the received outputtable current value and transmits the charging current command value to the main unit 1. The charging current command value is the command value of the charging current requested from the charging device A1. The main unit 1 controls the charging current to the electric vehicle 9 based on the received charging current command value. In other words, in the charging control of the electric vehicle 9, the charging device A1 outputs a charging current at the request of the electric vehicle 9. In this type of charging control, the charging device A1, which has a dynamic control function, can vary the output current value while the electric vehicle 9 is being charged. By changing this output current, the charging current command value from the electric vehicle 9 is adjusted, so the output can be increased or decreased during charging at the request of the charging device A1.

[0018] As shown in Figure 2, the main unit 1 includes a power supply unit 2, a communication unit 3, a control unit 4, and an output detection unit 5. Also as shown in Figure 2, the main unit 1 includes a communication line 13. In the main unit 1, the power supply unit 2, the communication unit 3, the control unit 4, and the output detection unit 5 communicate, for example, via the communication line 13. The standard for communication via the communication line 13 is not limited, but for example, it could be CAN (Controller Area Network) communication. Note that, unlike the illustrated example, the power supply unit 2, the communication unit 3, the control unit 4, and the output detection unit 5 may be configured to communicate one-to-one via separate communication lines. Also, as shown in Figure 2, the main unit 1 includes a main breaker 11 and a control breaker 12.

[0019] The control unit 4 is configured to control the charging device A1 and is implemented by, for example, a microcomputer or the like. The control unit 4 receives AC power from the power grid K via the control breaker 12. The control unit 4 converts the AC power input via the control breaker 12 into DC power and operates with the DC power. The control unit 4 controls the power supply unit 2. For example, the control unit 4 controls the power supply unit 2 to charge the electric vehicle 9 in constant current-constant voltage charging (CCCV charging: Constant Current-Constant Voltage charging). CCCV charging is a charging method in which charging is performed at a constant current in a region where the battery voltage of the electric vehicle 9 is low, and when approaching the maximum voltage, it switches to charging at a constant voltage and gradually reduces the charging current. In the present embodiment, the control unit 4 basically controls the power supply unit 2 in constant current-constant voltage charging, and this control is sometimes referred to as "basic control". Note that the basic control performed by the control unit 4 is not limited to constant current-constant voltage charging, and well-known charging methods can be appropriately adopted.

[0020] In charging the electric vehicle 9, the control unit 4 controls the output power (charging power) of the power supply unit 2 according to the set control mode. The control modes include a low voltage mode and a high voltage mode that perform charging in different voltage ranges. The low voltage mode is a mode in which charging is performed at a relatively low charging voltage, and the high voltage mode is a mode in which charging is performed at a relatively high charging voltage. Here, "relatively" means a comparison between the charging voltage in the low voltage mode and the charging voltage in the high voltage mode.

[0021] In addition, the control unit 4 controls the communication by the communication unit 3. The control unit 4 acquires the information or signal received by the communication unit 3. The control unit 4 transmits information or a signal via the communication unit 3. The control unit 4 acquires the information of the electric vehicle 9 by communicating with the electric vehicle 9 via the communication unit 3. The control unit 4 controls the output power of the power supply unit 2 based on various information. The various information includes information acquired by communication and information input from an operation unit (not shown).

[0022] The power supply unit 2 outputs DC power in response to a command from the control unit 4. The power supply unit 2 receives AC power from the power grid K via the main breaker 11. The power supply unit 2 converts the input AC power into DC power and outputs it. The power supply unit 2 supplies DC power (charging power) to the electric vehicle 9 via the power line 2a. The power line 2a passes through the charging cable 6 and is connected to the charging connector 7.

[0023] As shown in FIG. 2, the power supply unit 2 includes a low-voltage circuit unit 21 and a high-voltage circuit unit 22. The low-voltage circuit unit 21 and the high-voltage circuit unit 22 each include, for example, a converter and a smoothing circuit. The converter converts the AC power input from the power grid K into DC power in response to a command from the control unit 4. The converter is, for example, a PWM control type including switching elements. Note that the configuration of the converter is not limited to this. The smoothing circuit smooths and outputs the DC power output by the converter. Note that the specific configurations of the low-voltage circuit unit 21 and the high-voltage circuit unit 22 are not limited to this, as long as they can output DC power. For example, the low-voltage circuit unit 21 and the high-voltage circuit unit 22 may each include a transformer that boosts the AC voltage input from the power grid K. In the example shown in FIG. 2, power lines branch from the main breaker 11 and are connected to the low-voltage circuit unit 21 and the high-voltage circuit unit 22, respectively. Note that a switching switch may be provided at the portion where the power lines branch to switch between a state where AC power is supplied from the main breaker 11 to the low-voltage circuit unit 21 and a state where AC power is supplied from the main breaker 11 to the high-voltage circuit unit 22.

[0024] The low-voltage circuit section 21 outputs a charging voltage in low-voltage mode, and the high-voltage circuit section 22 outputs a charging voltage in high-voltage mode. The voltage range that the low-voltage circuit section 21 can output (hereinafter referred to as the "low-voltage range") may be determined by, for example, the specifications of the converter in the low-voltage circuit section 21 (e.g., withstand voltage and output voltage). The specific value of the low-voltage range is not limited in any way, but for example, it is between 150V and 550V. The voltage range that the high-voltage circuit section 22 can output (hereinafter referred to as the "high-voltage range") may be determined by the specifications of the converter in the high-voltage circuit section 22 (e.g., withstand voltage and output voltage). The specific value of the high-voltage range is not limited in any way, but for example, it is between 300V and 1000V. Note that the voltage ranges that the low-voltage circuit section 21 and the high-voltage circuit section 22 can output are not limited to these. However, the low-voltage range and the high-voltage range are set to partially overlap. The voltage range in which the low-voltage range and the high-voltage range overlap is called the "overlapping range." In the example above, the low-voltage range and the high-voltage range overlap in the range of 300V to 550V. The charging device A1 switches between low-voltage mode and high-voltage mode within this overlapping range.

[0025] In the power supply unit 2, the power supply unit 2 switches between outputting a charging voltage from the low-voltage circuit unit 21 and outputting a charging voltage from the high-voltage circuit unit 22 in response to a command from the control unit 4. For example, when the low-voltage mode is set, the control unit 4 outputs a charging voltage from the low-voltage circuit unit 21, and when the high-voltage mode is set, it outputs a charging voltage from the high-voltage circuit unit 22. If the aforementioned changeover switch is provided, the changeover switch may be switched according to the set control mode (low-voltage mode and high-voltage mode).

[0026] The communication unit 3 communicates with the electric vehicle 9, for example, via signal line 3a. Signal line 3a passes through the charging cable 6 and connects to the charging connector 7. The communication unit 3 communicates with each electric vehicle 9 according to, for example, the CAN (Controller Area Network) communication standard. The communication standard is not limited. The communication between the communication unit 3 and the electric vehicle 9 is not limited to wired communication using signal line 3a, but may also be wireless communication, for example. The communication unit 3 transmits information such as the aforementioned output current value to the electric vehicle 9. The communication unit 3 also receives information from the electric vehicle 9, such as the capacity of the battery 91, the current charge level (SoC: State of Charge), the voltage of the battery 91 (hereinafter referred to as "battery voltage"), the aforementioned charging current command value, and the minimum charging current value. The minimum charging current value is the minimum required charging current value set for the electric vehicle 9. The information transmitted and received between the communication unit 3 and the electric vehicle 9 is not limited.

[0027] The output detection unit 5 is installed on the power line 2a on the output side (charging cable 6 side) of the power supply unit 2. The output detection unit 5 detects, for example, the output current (charging current) and the output voltage (charging voltage) of the power supply unit 2. In addition, the output detection unit 5 may also detect the output power (charging power) from the output current and output voltage.

[0028] The charging cable 6 has power lines 2a and signal lines 3a inside, and a charging connector 7 is located at its end. The charging cable 6 is connected to the electric vehicle 9 when the charging connector 7 is connected to the plug-in connector 92 of the electric vehicle 9. The electric vehicle 9, to which the charging connector 7 is connected, communicates with the communication unit 3 via the signal lines 3a and the charging connector 7. The electric vehicle 9 also charges its battery 91 with power supplied from the power supply unit 2 via the power lines 2a and the charging connector 7.

[0029] As shown in Figures 1 and 2, the charging connector 7 is attached to the end of the charging cable 6. Charging power is supplied from the power supply unit 2 to the charging connector 7 via the power line 2a in the charging cable 6. The charging connector 7 comprises a body and a plug. In the charging connector 7, the aforementioned body is the part that the user grasps and has a handle formed therein. Inside the body of the charging connector 7 are power lines connected to the power line 2a in the corresponding charging cable 6, and signal lines connected to the signal line 3a in the corresponding charging cable 6. In the charging connector 7, the aforementioned plug is the part that connects to the plug-in connector 92 of the electric vehicle 9. The plug of the charging connector 7 is, for example, a cylindrical metal member located at the tip of the body. Inside the plug of the charging connector 7 are power terminals that conduct to the power line 2a in the corresponding body, and signal terminals that conduct to the signal line 3a in the corresponding body. In addition to the body and plug, the charging connector 7 comprises a mechanism for locking the charging connector 7 to the plug-in connector 92, and a button for removal. Note that the configuration of the charging connector 7 is not limited to this.

[0030] Next, a detailed configuration example of the control unit 4 will be described. As shown in Figure 2, the control unit 4 includes a monitoring unit 41, a switching unit 42, and an adjustment unit 43.

[0031] The monitoring unit 41 monitors the output voltage (charging voltage) and output current (charging current) of the power supply unit 2 using the values ​​detected by the output detection unit 5.

[0032] The switching unit 42 switches between low-voltage mode and high-voltage mode according to the charge status of the battery 91 of the electric vehicle 9. When the switching unit 42 is in low-voltage mode, if the charge voltage monitored by the monitoring unit 41 (the value of the charge voltage detected by the output detection unit 5) exceeds a predetermined switching threshold, the switching unit 42 automatically switches to high-voltage mode. The switching threshold is set within the overlapping range (the voltage range in which the high-voltage range and the low-voltage range overlap). In other words, the switching threshold is a value included in the overlapping range. For example, in an example where the low-voltage range is 150V to 550V and the high-voltage range is 300V to 1000V, the switching threshold is 520V. Note that as the charge rate of the battery 91 of the electric vehicle 9 increases, the battery voltage of the electric vehicle 9 increases. The power supply unit 2 outputs a charge voltage equivalent to the battery voltage of the electric vehicle 9. Therefore, switching the control mode (low voltage mode and high voltage mode) according to the charging voltage can be said to be switching the control mode (low voltage mode and high voltage mode) according to the charging state of the battery 91 of the electric vehicle 9. In the charging device A1, the switching unit 42 switches from the low voltage mode to the high voltage mode when constant current charging is being performed in the basic control (CCCV charging) described above.

[0033] The adjustment unit 43 adjusts the charging power (charging current and charging voltage) output from the power supply unit 2. In the basic control described above, the adjustment unit 43 controls the power supply unit 2 so that the charging current becomes the charging current command value received from the electric vehicle 9, and the charging voltage becomes the set voltage value corresponding to the battery voltage of the electric vehicle 9. In the basic control, the adjustment unit 43 sets the outputtable current value to the set current value corresponding to the basic control, thereby setting the charging current command value received from the electric vehicle 9 to a value corresponding to the set current value. In other words, in the basic control, the adjustment unit 43 adjusts the charging current to a value corresponding to the set current value in the basic control. The adjustment unit 43 controls the output from the power supply unit 2 (low-voltage circuit unit 21 or high-voltage circuit unit 22) by outputting a control signal to the power supply unit 2. For example, in low-voltage mode, the adjustment unit 43 outputs a control signal to the converter of the low-voltage circuit unit 21, causing the low-voltage circuit unit 21 to output a charging voltage, and in high-voltage mode, it outputs a control signal to the converter of the high-voltage circuit unit 22, causing the high-voltage circuit unit 22 to output a charging voltage. If the converters of the low-voltage circuit unit 21 and the high-voltage circuit unit 22 are PWM-controlled converters, the control signal is a PWM signal.

[0034] The adjustment unit 43 outputs a charging voltage from the low-voltage circuit unit 21 when the low-voltage mode is set, and outputs a charging voltage from the high-voltage circuit unit 22 when the high-voltage mode is set. Therefore, when switching control modes, the adjustment unit 43 switches between a state in which the charging voltage is output from the low-voltage circuit unit 21 and a state in which the charging voltage is output from the high-voltage circuit unit 22. For example, the adjustment unit 43 outputs a control signal to the converter of the low-voltage circuit unit 21 and does not output a control signal to the converter of the high-voltage circuit unit 22, thereby setting the system to output a charging voltage from the low-voltage circuit unit 21, or it does not output a control signal to the converter of the low-voltage circuit unit 21 and outputs a control signal to the converter of the high-voltage circuit unit 22, thereby setting the system to output a charging voltage from the high-voltage circuit unit 22. In the charging device A1, when switching between a state in which the charging voltage is output from the low-voltage circuit section 21 (low-voltage mode) and a state in which the charging voltage is output from the high-voltage circuit section 22 (high-voltage mode), there may be a predetermined switching time during which the charging current becomes 0 A (i.e., the output from the power supply section 2 stops).

[0035] The adjustment unit 43 temporarily reduces the charging current using the dynamic control function described above when switching from low-voltage mode to high-voltage mode. For example, when low-voltage mode is set, if the charging voltage exceeds the current limit threshold, the adjustment unit 43 reduces the outputable current value to the minimum charging current value. Preferably, the outputable current value is gradually changed from the set current value in the basic control to the minimum charging current value. The current limit threshold is a value slightly lower than the switching threshold; for example, in the case where the switching threshold is 520V, the current limit threshold is 515V. By setting the outputable current value to the minimum charging current value, the adjustment unit 43 makes the charging current command value from the electric vehicle 9 the minimum charging current value. Therefore, the adjustment unit 43 controls the power supply unit 2 (low-voltage circuit unit 21) so that the charging current becomes the minimum charging current value (charging current command value). In this state, when the charging voltage exceeds the switching threshold, the switching unit 42 switches from low-voltage mode to high-voltage mode, and the adjustment unit 43 stops the low-voltage circuit unit 21 and activates the high-voltage circuit unit 22. In other words, it switches from the low-voltage circuit unit 21 to the high-voltage circuit unit 22. When switching from low-voltage mode to high-voltage mode, the adjustment unit 43 returns the charging current to a preset current value (a set value in constant current control), thereby canceling the temporary drop in charging current.

[0036] As mentioned above, the charging device A1 transmits the maximum output current value of the charging device A1 to the electric vehicle 9, and the electric vehicle 9 requests a charging current command value from the charging device A1 within the range of the received maximum output current value. Some electric vehicles 9 will detect a charging error and stop charging if the charging current deviates from the charging current command value by 10% or more (maximum of 20A) of the electric vehicle 9's maximum charging current value for 1 second or more. The maximum charging current value is the maximum charging current allowed by the electric vehicle 9 and is set in the electric vehicle 9. Note that the duration for which a charging error is detected is not limited to the 1 second mentioned above and may vary depending on the vehicle model. For example, in an electric vehicle 9 with a maximum charging current value of 125A, a charging error will be detected and charging will stop if the charging current from the charging device A1 deviates from the charging current command value by ±12.5A or more for 1 second or more. Therefore, the charging device A1 performs the following processing to prevent the electric vehicle 9 from detecting a charging error even if the charging current becomes 0A when switching from the low-voltage circuit section 21 (low-voltage mode) to the high-voltage circuit section 22 (high-voltage mode). The charging device A1 (adjustment section 43) reduces the outputable current value to be transmitted to the electric vehicle 9 to the minimum charging current value of the electric vehicle 9 when switching from the low-voltage circuit section 21 (low-voltage mode) to the high-voltage circuit section 22 (high-voltage mode), and transmits it. The electric vehicle 9 then requests a charging current command value from the charging device A1 within the range of the received outputable current value (minimum charging current value of the electric vehicle 9). For example, if the minimum charging current value of the electric vehicle 9 is 10A, the electric vehicle 9 requests a charging current command value of 10A from the charging device A1. As a result, the charging current command value transmitted to the charging device A1 will be less than 10% of the maximum charging current value of the electric vehicle 9 (less than 12.5A if the maximum charging current value is 125A), thus preventing the electric vehicle 9 from detecting a charging error even if the charging current from the charging device A1 becomes 0A.

[0037] Figure 3 shows the charging control of the power supply unit 2 performed by the control unit 4. The process shown in Figure 3 is repeatedly executed, for example, while the main unit 1 and the electric vehicle 9 are connected.

[0038] First, the control unit 4 obtains battery voltage information (or SoC information) from the electric vehicle 9 and determines whether to perform charging in low-voltage mode or high-voltage mode based on the battery voltage (or SoC information) (S101). For example, if the battery voltage is within the low-voltage range, the control unit 4 sets the control mode to low-voltage mode and starts charging in low-voltage mode (S102). On the other hand, if the battery voltage is within the high-voltage range, the control unit 4 sets the control mode to high-voltage mode and starts charging in high-voltage mode (S109). If the battery voltage is within the overlapping range, charging may be started in either low-voltage mode or high-voltage mode. However, if high-voltage mode is set in the control mode and charging is started in high-voltage mode, there is no need to switch the control mode from low-voltage mode to high-voltage mode during charging.

[0039] Next, the control unit 4 determines whether or not charging of the electric vehicle 9 is complete (S103). For example, the control unit 4 determines that charging of the electric vehicle 9 is complete when the SoC of the electric vehicle 9 (storage battery 91) exceeds a preset upper limit (i.e., when charging of the electric vehicle 9 is complete), when the user of the charging device A1 performs a charging stop operation, or when a preset time has elapsed since charging started. Note that the criteria for determining the completion of charging of the electric vehicle 9 are not limited to these. If the control unit 4 determines that charging of the electric vehicle 9 is complete (S103:YES), it terminates the charging control of the connected electric vehicle 9. For example, if the electric vehicle 9 only supports low-voltage charging, charging of the electric vehicle 9 is terminated in step S103. On the other hand, if the control unit 4 determines that charging of the electric vehicle 9 is not complete (S103:NO), it proceeds to the next process (S104).

[0040] Next, the control unit 4 determines whether the charging voltage is equal to or greater than the current control threshold (S104). If the control unit 4 determines that the charging voltage is less than the current limit threshold (S104: NO), it returns to the process in step S102 and repeats the processes in steps S103 and S104 until charging of the electric vehicle 9 is completed or the charging voltage is equal to or greater than the current limit threshold. Thus, the control unit 4 continues charging in low-voltage mode. On the other hand, if the control unit 4 determines that the charging voltage is equal to or greater than the current limit threshold (S104: YES), it temporarily reduces the charging current (S105). For example, in step S105, the control unit 4 uses the dynamic control function to reduce the output current value to be transmitted to the electric vehicle 9 to the minimum charging current value set for the electric vehicle 9. As a result, the electric vehicle 9 transmits the charging current command value to the charging device A1 (via the communication unit 3 to the control unit 4), so the charging current to the electric vehicle 9 is temporarily reduced to the minimum charging current value.

[0041] Next, the control unit 4 determines whether the charging voltage is above the switching threshold (S106). If the control unit 4 determines that the charging voltage is below the switching threshold (S106: NO), it repeats the process in step S106 until the charging voltage is above the switching threshold. On the other hand, if the control unit 4 determines that the charging voltage is above the switching threshold (S106: YES), the switching unit 42 switches the control mode from low voltage mode to high voltage mode (S107). As a result, charging in low voltage mode stops and charging in high voltage mode begins. Then, the control unit 4 cancels the temporary decrease in charging current (S108). For example, in step S108, the control unit 4 returns the outputtable current value transmitted to the electric vehicle 9 to the set current value during the basic control (for example, the set current value in constant current control). As a result, the electric vehicle 9 transmits the charging current command value to the charging device A1 (via the communication unit 3 to the control unit 4) with the charging current command value below the aforementioned set current value, thus canceling the temporary decrease in charging current.

[0042] Next, the control unit 4 determines whether or not charging of the electric vehicle 9 is complete (S110). The criteria for determining whether charging of the electric vehicle 9 is complete in step S110 are the same as the criteria for determining whether charging of the electric vehicle 9 is complete in step S103. If the control unit 4 determines that charging of the electric vehicle 9 is complete (S110: YES), it terminates the charging control of the connected electric vehicle 9. For example, if only high-voltage mode charging is performed, or if charging starts in low-voltage mode and is switched to high-voltage mode midway through, charging of the electric vehicle 9 may be terminated in step S110. On the other hand, if the control unit 4 determines that charging of the electric vehicle 9 is not complete (S110: NO), it continues charging in high-voltage mode until charging of the electric vehicle 9 is complete.

[0043] Note that the charging control of the control unit 4 shown in Figure 3 is just one example and is not limited thereto.

[0044] Next, the output change of the power supply unit 2 during mode switching from low voltage mode to high voltage mode will be explained with reference to Figure 4. Figure 4(a) shows the simulation results for charging device A1 when the charging current is temporarily reduced, and Figure 4(b) shows the simulation results for a comparison charging device when the charging current is not temporarily reduced. In Figures 4(a) and (b), the solid line shows the change in charging voltage, and the dashed line shows the change in charging current. In Figures 4(a) and (b), it is assumed that charging is performed in low voltage mode at the start of the simulation. In the basic control of the simulation, it is assumed that charging is performed with a constant current of 125A.

[0045] As shown in Figure 4(a), in the charging device A1, from the start of the simulation until time t11, the charging voltage (battery voltage) gradually increases due to constant current charging. At time t11, the charging voltage exceeds the current limit threshold, so from time t11, the charging current gradually decreases to the minimum charging current value. After time t11, the charging current is still output, so the charging voltage (battery voltage) gradually increases during this time as well. At time t12, the charging voltage exceeds the switching threshold, so the system switches from low-voltage mode to high-voltage mode. When switching from low-voltage mode to high-voltage mode, the power supply unit 2 needs to switch from the low-voltage circuit unit 21 to the high-voltage circuit unit 22. For this reason, the supply of charging power (charging current and charging voltage) is stopped for a predetermined switching period Tsw. At time t13, charging in high-voltage mode begins, and the temporary decrease in charging current is released. As a result, charging is performed under basic control from time t13 onwards. In the example shown in Figure 4(a), the control unit 4 (adjustment unit 43) gradually increases the charging current to the set current value in the basic control after charging in high-voltage mode has started.

[0046] On the other hand, as shown in Figure 4(b), in the comparison charging device, from the start of the simulation until time t21, the charging voltage (battery voltage) gradually increases by constant current charging, similar to charging device A1. Then, at time t21, the charging voltage exceeds the switching threshold, so it switches from low-voltage mode to high-voltage mode. When switching from low-voltage mode to high-voltage mode, the power supply unit 2 needs to switch from the low-voltage circuit unit 21 to the high-voltage circuit unit 22. For this reason, the supply of charging power (charging current and charging voltage) is stopped for a predetermined switching period Tsw. When the supply of this charging power is stopped, the charging current and charging voltage abruptly become 0 (zero) from time t21 to time t22. Then, at time t23, charging in high-voltage mode begins, and from time t23 onward, charging is performed under basic control.

[0047] As can be seen from the simulation results in Figures 4(a) and 4(b), in the comparison charging device, as shown in Figure 4(b), when the charging voltage exceeds the switching threshold, the output of the charging current is instantaneously stopped, causing a rapid change (decrease) in the charging current. On the other hand, in charging device A1, as shown in Figure 4(a), when the charging voltage exceeds the current limiting threshold, the charging current is temporarily reduced, so even when the charging voltage exceeds the switching threshold and the output of the charging current is stopped, a rapid change (decrease) in the charging current is suppressed.

[0048] The operation and effects of the charging device A1 are as follows:

[0049] In the charging device A1, the control unit 4 includes an adjustment unit 43 that adjusts the charging current and charging voltage output from the power supply unit 2, and a switching unit 42 that switches between a high-voltage mode and a low-voltage mode, which charge in different voltage ranges. With this configuration, when an electric vehicle 9 that only supports low-voltage charging is connected, charging can be performed in the low-voltage range by setting the low-voltage mode. On the other hand, when an electric vehicle 9 that can be charged at high voltage is connected, charging can be performed in the high-voltage range by setting the high-voltage mode. Therefore, the charging device A1 can charge the electric vehicle 9 at either low voltage or high voltage.

[0050] In the charging device A1, the adjustment unit 43 temporarily reduces the charging current when switching from low-voltage mode to high-voltage mode, and the switching unit 42 switches from low-voltage mode to high-voltage mode while the charging current is temporarily reduced. With this configuration, as can be seen from the simulation results shown in Figure 4(a), abrupt changes in the charging current are suppressed when switching from low-voltage mode to high-voltage mode. Some electric vehicles 9 are configured to detect abrupt changes in current, determine it as a charging error, and forcibly stop charging. If the charging current is not temporarily reduced when switching from low-voltage mode to high-voltage mode, the charging current may change abruptly when switching control modes, as shown in Figure 4(b). For this reason, electric vehicles 9 may detect a charging error and forcibly stop charging. In contrast, the charging device A1 suppresses abrupt changes in the charging current when switching control modes by temporarily reducing the charging current when switching from low-voltage mode to high-voltage mode. Furthermore, when switching from low-voltage mode to high-voltage mode, the charging device A1 (adjustment unit 43) gradually changes the charging current to an extent that does not cause the electric vehicle 9 to detect a charging error. This suppresses the detection of a charging error by the electric vehicle 9, even if the electric vehicle 9 is configured to detect a charging error due to a sudden change in current. Therefore, the charging device A1 can prevent the electric vehicle 9 from detecting a charging error, thus preventing the charging from being forcibly stopped.

[0051] In the charging device A1, the power supply unit 2 includes a low-voltage circuit unit 21 that outputs a charging voltage in low-voltage mode and a high-voltage circuit unit 22 that outputs a charging voltage in high-voltage mode. The adjustment unit 43 switches between outputting the charging voltage from the low-voltage circuit unit 21 and outputting the charging voltage from the high-voltage circuit unit 22 when switching modes. In this configuration, it is necessary to switch the circuit that outputs the charging voltage itself, so a period of 0A of charging current is required when switching from the low-voltage circuit unit 21 to the high-voltage circuit unit 22. In other words, in a configuration that switches the circuit that outputs the charging voltage itself, a sudden change in charging current may occur when switching control modes. Therefore, in a configuration that requires switching between the low-voltage circuit unit 21 and the high-voltage circuit unit 22, temporarily reducing the charging current is effective in suppressing a sudden change in charging current when switching control modes and avoiding the detection of charging errors. In other words, the charging device A1 is a preferred configuration for preventing the electric vehicle 9 from being forcibly stopped due to the detection of a charging error.

[0052] In the charging device A1, the switching unit 42 automatically switches to high-voltage mode when the charging voltage exceeds a predetermined threshold in low-voltage mode. In this configuration, the charging device A1 automatically switches from low-voltage mode to high-voltage mode according to the charge state of the battery 91 of the electric vehicle 9. Therefore, if the charging current is not temporarily reduced when switching from low-voltage mode to high-voltage mode, charging may be stopped due to the detection of a charging error without the user of the charging device A1's knowledge. If charging is stopped, for example, when returning to the parking location of the electric vehicle 9 after shopping, the user may find out that charging has stopped, and there is a risk that the electric vehicle 9 has not been charged. Therefore, in a configuration in which the switching from low-voltage mode to high-voltage mode is performed automatically, temporarily reducing the charging current is effective in suppressing abrupt changes in the charging current when the control mode is switched, and in avoiding the detection of a charging error. In other words, the charging device A1 is a preferred configuration for suppressing the forced stopping of charging due to the detection of a charging error in the electric vehicle 9.

[0053] In the charging device A1, the electric vehicle 9 is compatible with the output control function performed by the charging device A1, and the adjustment unit 43 reduces the charging current to the minimum charging current value obtained from the electric vehicle 9. In this embodiment, the charging device A1 reduces the outputable current value transmitted to the electric vehicle 9 from the set current value in the basic control to the minimum charging current value, so that the charging current command value requested from the electric vehicle 9 becomes less than or equal to the minimum charging current value, and thus reduces the charging current to the minimum charging current value. As described above, some electric vehicles 9 detect a charging error if the charging current deviates by 10% or more from the charging current command value to the maximum charging current value of the electric vehicle 9 for more than one second. Therefore, in the charging device A1, when switching from the low voltage mode to the high voltage mode, the outputable current value is temporarily reduced to the minimum charging current value, thereby making the charging current command value from the electric vehicle 9 the minimum charging current value. As a result, for example, if the maximum charging current is 125A and the minimum charging current is 10A, when switching from low-voltage mode to high-voltage mode, the charging current will temporarily become 10A. Even if the charging current becomes 0A in this state, it will not deviate from the charging current command value by more than 10% of the maximum charging current value of the electric vehicle 9. In other words, the detection of a charging error in the electric vehicle 9 can be suppressed. Therefore, the charging device A1 can suppress forced stopping of charging by the electric vehicle 9 by reducing the charging current to the minimum charging current value when switching from low-voltage mode to high-voltage mode. If the change in the output current value by the charging device A1, from the set current value in the basic control to the minimum charging current value, is more than 10% of the maximum charging current value of the electric vehicle 9, it is preferable for the charging device A1 to gradually (or stepwise) reduce the output current value so that, for example, the change per second is less than 10% of the maximum charging current value of the electric vehicle 9.

[0054] In the charging device A1, the adjustment unit 43 releases the reduction in charging current when switching from low-voltage mode to high-voltage mode. With this configuration, when switching from low-voltage mode to high-voltage mode, the charging current returns to the current value set in the basic control. Therefore, the charging device A1 can avoid a prolonged state of reduced charging current.

[0055] In the above embodiment, the power supply unit 2 includes a low-voltage circuit unit 21 and a high-voltage circuit unit 22, and an example was shown in which the circuit switches between low-voltage mode and high-voltage mode. In contrast to this configuration, the power supply unit 2 may include a common circuit (for example, a converter and a smoothing circuit) for both low-voltage mode and high-voltage mode, and the output voltage (charging voltage) for low-voltage mode and high-voltage mode may be switched by software control of the control unit 4. In such a configuration as well, since the charging current may temporarily become 0 A due to the software switching of the control unit 4, temporarily reducing the charging current when switching from low-voltage mode to high-voltage mode can suppress the detection of charging errors.

[0056] In the above embodiment, the switching unit 42 is shown to automatically switch from low-voltage mode to high-voltage mode. In contrast to this configuration, the switching unit 42 may also be configured to switch the control mode by operating an operation unit (not shown) by a user of the charging device of this disclosure. In such a configuration as well, since the charging current may temporarily become 0 A when switching from low-voltage mode to high-voltage mode, temporarily reducing the charging current can suppress the detection of charging errors.

[0057] In the above embodiment, an example was shown in which the electric vehicle 9 supports a dynamic control function. In contrast to this configuration, the electric vehicle 9 does not have to support a dynamic control function. In this example, for example, the charging device of the present disclosure can temporarily reduce the charging current when switching from a low voltage mode to a high voltage mode by temporarily ignoring the charging current command value received from the electric vehicle 9 and reducing the charging current to a minimum charging current value.

[0058] The charging device relating to this disclosure is not limited to the embodiments described above. The specific configuration of each part of the charging device relating to this disclosure can be modified in various ways. [Explanation of Symbols]

[0059] A1: Charging device, 1: Main unit, 2: Power supply unit, 21: Low-voltage circuit unit, 22: High-voltage circuit unit, 3: Communication unit, 4: Control unit, 41: Monitoring unit (voltage monitoring unit), 42: Switching unit, 43: Adjustment unit, 5: Output detection unit, 6: Charging cable, 7: Charging connector, 9: Electric vehicle (electric mobile device), 91: Storage battery

Claims

1. A charging device for charging the battery of an electric mobile vehicle that moves by driving an electric motor with the power of the battery, A power supply unit that outputs power for charging the aforementioned storage battery, A control unit that controls the power supply unit, A communication unit that communicates with the aforementioned electric mobile device, Equipped with, The control unit includes an adjustment unit that adjusts the charging current and charging voltage output from the power supply unit, and a switching unit that switches between a high-voltage mode and a low-voltage mode that charge in different voltage ranges. The adjustment unit temporarily reduces the charging current when switching from the low-voltage mode to the high-voltage mode. The switching unit is a charging device that switches from the low-voltage mode to the high-voltage mode while the charging current is temporarily reduced.

2. The power supply unit includes a low-voltage circuit unit that outputs the charging voltage in the low-voltage mode and a high-voltage circuit unit that outputs the charging voltage in the high-voltage mode. The charging device according to claim 1, wherein the adjustment unit switches between a state in which the charging voltage is output from the low-voltage circuit unit and a state in which the charging voltage is output from the high-voltage circuit unit when the mode is switched.

3. The control unit includes a voltage monitoring unit that monitors the charging voltage, The switching unit automatically switches to the high-voltage mode when the charging voltage in the low-voltage mode exceeds a predetermined threshold. The charging device according to claim 2, wherein the threshold value is a value within the overlapping range where the voltage range that can be output in the low-voltage mode and the voltage range that can be output in the high-voltage mode overlap.

4. The aforementioned electric mobile unit corresponds to the output control function performed by the charging device, The communication unit obtains the minimum charging current value set for the electric mobile device from the electric mobile device. The charging device according to any one of claims 1 to 3, wherein the adjustment unit reduces the charging current to the minimum charging current value when the mode is switched.

5. The charging device according to any one of claims 1 to 3, wherein the adjustment unit releases the reduction in charging current when switching from the low-voltage mode to the high-voltage mode.

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