Charging device

Abstract

In a charging device having a first switch capable of interconnecting the outputs of a plurality of power converters, welding of the first switch can be detected without providing a dedicated mechanism. [Solution] The charging device of the present invention comprises a plurality of power converters, a first switch capable of interconnecting the outputs of a pair of the plurality of power converters, a plurality of second switches connected respectively between the output of each of the plurality of power converters and each of a plurality of charging ports, a voltage sensor detecting the voltage values ​​of a plurality of voltage lines connecting the outputs of the plurality of power converters and the plurality of second switches, and a fault detection unit that detects a welding fault in the first switch when the difference in voltage values ​​of a pair of voltage lines connected to the outputs of the pair of power converters detected by the voltage sensor is greater than a threshold value when the outputs of a pair of power converters outputting DC voltage are connected to each other by the first switch.

Description

[Technical Field]

[0001] The present invention relates to a charging device. [Background technology]

[0002] Patent Document 1 discloses a quick charger that has multiple power conversion units that generate DC voltage and multiple switches that can connect the outputs of the multiple power conversion units to one or more of multiple power supply connectors, and that can simultaneously charge the batteries of multiple electric vehicles.The quick charger in Patent Document 1 connects multiple auxiliary contacts in parallel, each corresponding to a different one of the switches, and detects welding of any of the switches by recognizing that any of the auxiliary contacts is on. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-180549 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 has a problem of high cost because it requires multiple auxiliary contacts to detect welding of any of multiple switches and a dedicated welding detection mechanism that includes signal lines connected to the multiple auxiliary contacts.

[0005] An object of the present invention is to detect welding of a first switch in a charging device having a first switch capable of interconnecting the outputs of a plurality of power converters, without providing a dedicated mechanism. [Means for solving the problem]

[0006] The charging device of the present invention includes a plurality of power converters that each converts AC voltage to DC voltage, a first switch that can connect the outputs of a pair of the plurality of power converters to each other, a plurality of second switches that are respectively connected between the output of each of the plurality of power converters and each of a plurality of charging ports to which a device to be charged can be connected, a voltage sensor that detects the voltage values ​​of a plurality of voltage lines that respectively connect the outputs of the plurality of power converters to the plurality of second switches, and a fault detection unit that detects a welding fault of the first switch when the difference in voltage values ​​of the pair of voltage lines connected to the outputs of the pair of power converters, detected by the voltage sensor, is greater than a threshold value when the outputs of the pair of power converters that output DC voltage are connected to each other by the first switch. [Effects of the Invention]

[0007] According to the present invention, in a charging device having a first switch capable of interconnecting the outputs of a plurality of power converters, welding of the first switch can be detected without providing a dedicated mechanism. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a circuit block diagram illustrating an example of a charging device according to an embodiment of the present invention. [Figure 2] 10 is a flowchart showing an example of an operation performed by the charge control unit of FIG. 1 to determine whether or not there is a welding fault in the selector switch SW1. [Figure 3] 10 is a flowchart showing an example of an operation performed by the charge control unit of FIG. 1 to determine whether or not another fault has occurred in the selector switch SW1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted. Reference numerals indicating voltages are also used to indicate voltage lines.

[0010] Fig. 1 is a circuit block diagram showing an example of a charging device according to an embodiment of the present invention. The charging device 100 shown in Fig. 1 includes a plurality of AC / DC converters 110a, 110b, voltage sensors 120a, 120b, a charging control unit 130 including a fault detection unit 132, a changeover switch SW1, and a plurality of changeover switches SW2a, SW2b. The AC / DC converters 110a, 110b are an example of a power converter. The changeover switch SW1 is an example of a first switch. The changeover switches SW2a, SW2b are an example of a second switch.

[0011] The charging device 100 has a function of outputting a DC voltage to one or both of the multiple charging ports 200a, 200b. For example, the charging device 100 can simultaneously charge the batteries of multiple vehicles 300a, 300b, such as electric vehicles, connected to the charging ports 200a, 200b. The vehicles 300a, 300b are examples of devices to be charged. In the following description, when the charging ports 200a, 200b are described without distinction, they are also referred to as charging port 200. When the vehicles 300a, 300b are described without distinction, they are also referred to as vehicle 300.

[0012] The AC / DC converters 110a and 110b convert AC voltage from an AC power supply AC into DC voltages DCa and DCb, respectively. The changeover switch SW1 can interconnect the output of the AC / DC converter 110a and the output of the AC / DC converter 110b. One end of the changeover switch SW2a is connected to the output of the AC / DC converter 110a via a voltage line DCa, and the other end of the changeover switch SW2a is connected to the charging port 200a. One end of the changeover switch SW2b is connected to the output of the AC / DC converter 110b via a voltage line DCb, and the other end of the changeover switch SW2b is connected to the charging port 200b.

[0013] Voltage sensor 120a detects a voltage value VDCa of DC voltage DCa and outputs the detected voltage value VDCa to fault detection unit 132. Voltage sensor 120b detects a voltage value VDCb of DC voltage DCb and outputs the detected voltage value VDCb to fault detection unit 132. Fault detection unit 132 detects a fault in selector switch SW1 based on the voltage values ​​VDCa and VDCb received from voltage sensors 120a and 120b. An example of the operation of fault detection unit 132 will be described with reference to FIGS. 2 and 3. Note that charging control unit 130 uses the DC voltage values ​​VDCa and VDCb detected by voltage sensors 120a and 120b to control charging of vehicle 300.

[0014] When the fault detection unit 132 detects a fault in the selector switch SW1, the charging control unit 130 may display the details of the fault and a warning message to the user, etc. on a display unit (not shown) provided in the charging device 100. Furthermore, when the fault detection unit 132 detects a fault in the selector switch SW1, the charging control unit 130 may output a sound from a speaker (not shown) provided in the charging device 100 indicating the details of the fault and a warning message to the user, etc.

[0015] For example, charging control unit 130 may be realized by a processor such as a CPU (Central Processing Unit) mounted in charging control unit 130 executing a charging control program. Charging control unit 130 outputs control signals to AC / DC converters 110a and 110b, respectively, for controlling the operation / stop of AC / DC converters 110a and 110b. Charging control unit 130 outputs control signals to selector switches SW1, SW2a, and SW2b, respectively, for controlling the on / off of selector switches SW1, SW2a, and SW2b.

[0016] 1 shows an example in which selector switches SW1 and SW2b are turned on and selector switch SW2a is turned off, and AC / DC converters 110a and 110b are operated in parallel, allowing charging device 100 to rapidly charge vehicle 300b connected to charging port 200b using charging currents Ia+Ib from both AC / DC converters 110a and 110b.

[0017] Fig. 2 is a flowchart showing an example of an operation performed by the charging control unit 130 in Fig. 1 to determine whether or not there is a welding fault in the selector switch SW1. The operation of determining whether or not there is a welding fault in the selector switch SW1 shown in Fig. 2 is performed when a plurality of AC / DC converters 110a, 110b are used to output charging current to one charging port 200a (or 200b). That is, the charging control unit 130 can determine whether or not there is a welding fault in the selector switch SW1 while charging the vehicle 300.

[0018] First, in S10, charging control unit 130 turns on selector switch SW1 and turns on one of selector switches SW2a and SW2b. As a result, voltage lines DCa and DCb are connected to each other, and the outputs of AC / DC converters 110a and 110b are connected to one of charging ports 200. Furthermore, charging control unit 130 causes AC / DC converter 110a to output DC voltage DCa, causes AC / DC converter 110b to output DC voltage DCb, and supplies charging current Ia+Ib to one of the charging ports.

[0019] Next, in S11, the fault detection unit 132 determines the difference between the voltage values ​​VDCa and VDCb from the voltage sensors 120a and 120b while the voltage lines DCa and DCb are connected to each other. The fault detection unit 132 determines whether the determined difference is greater than a preset threshold. If the difference between the voltage values ​​VDCa and VDCb is equal to or less than the threshold, the fault detection unit 132 determines that the on-resistance of the selector switch SW1 is low, and executes S12. If the difference between the voltage values ​​VDCa and VDCb is greater than the threshold, the fault detection unit 132 determines that the on-resistance of the selector switch SW1 is high, and executes S13.

[0020] In S12, the failure detection unit 132 determines that there is no welding failure of the selector switch SW1, ends the determination process in Fig. 2, and continues charging the vehicle 300. In S13, the failure detection unit 132 determines that there is a welding failure of the selector switch SW1, and executes S14.

[0021] In S14, the charging control unit 130 displays the details of the malfunction and a warning message to the user, etc. on the display unit of the charging device 100, and ends the determination process of Fig. 2. Alternatively, the charging control unit 130 outputs a sound from the speaker of the charging device 100 to the details of the malfunction and a warning message to the user, etc., and ends the determination process of Fig. 2. The user, etc., who is charging the vehicle 300 using the charging device 100 can stop the charging operation based on the warning from the charging device 100.

[0022] If a welding failure of the selector switch SW1 is detected in S13, the charging control unit 130 may stop charging of the vehicle 300. After S13, the charging control unit 130 may end the determination process in Fig. 2 without performing S14. In this case, the charging control unit 130 may voluntarily stop the charging operation.

[0023] Fig. 3 is a flowchart showing an example of an operation of determining whether or not another fault has occurred in the selector switch SW1 by the charging control unit 130 in Fig. 1. For example, the operation of determining whether or not another fault has occurred in the selector switch SW1 shown in Fig. 3 is performed before the vehicle 300 is charged using the charging device 100.

[0024] First, in S20, charging control unit 130 turns off changeover switch SW1 and causes AC / DC converter 110a to output direct current voltage DCa.

[0025] Next, in S21, fault detection unit 132 determines whether voltage sensor 120a detects voltage value VDCa and whether voltage sensor 120b detects voltage value VDCb. If voltage value VDCa is detected and voltage value VDCb is not detected (for example, 0 V), fault detection unit 132 performs S22. If both voltage values ​​VDCa and VDCb are detected, fault detection unit 132 performs S26.

[0026] In S22, charging control unit 130 turns on selector switch SW1 to cause AC / DC converter 110a to output direct current voltage DCa.

[0027] Next, in S23, fault detection unit 132 determines whether voltage value VDCa detected by voltage sensor 120a and voltage value VDCb detected by voltage sensor 120b are equal. If voltage value VDCa and voltage value VDCb are equal, fault detection unit 132 performs S24, and if voltage value VDCa and voltage value VDCb are not equal, performs S25.

[0028] In S24, the failure detection unit 132 determines that the changeover switch SW1 is normal, and ends the determination process of FIG.

[0029] In S25, the fault detection unit 132 detects an open fault in the selector switch SW1, and executes S27. When the fault detection unit 132 detects an open fault in the selector switch SW1, the charging control unit 130 prohibits the power sharing operation that operates both of the AC / DC converters 110a and 110b to charge the vehicle 300 with the charging current Ia+Ib.

[0030] Meanwhile, in S26, the fault detection unit 132 detects a short fault in the selector switch SW1, and executes S27. If the fault detection unit 132 detects a short fault in the selector switch SW1, the charging control unit 130 prohibits the simultaneous use of multiple charging ports 200. The simultaneous use of multiple charging ports 200 is an operation in which multiple charging ports 200 are used simultaneously to charge multiple vehicles 300 simultaneously.

[0031] In S27, the charging control unit 130 displays the details of the malfunction and a warning message to the user on the display unit of the charging device 100, and ends the determination process of Fig. 3. Alternatively, the charging control unit 130 outputs the details of the malfunction and a warning message to the user from a speaker of the charging device 100, and ends the determination process of Fig. 3. A user who is charging the vehicle 300 using the charging device 100 can recognize an unavailable charging mode among the multiple charging modes of the charging device 100. Note that the charging control unit 130 may end the determination process of Fig. 3 after S25 and S26 without performing S27.

[0032] In FIG. 3, even if the symbols DCa of S20 and S22 are changed to DCb and the symbols VDCa and VDCb of S21 and S23 are swapped, open circuit failures and short circuit failures of the changeover switch SW1 can still be detected.

[0033] As described above, in this embodiment, in charging device 100 having changeover switch SW1 that can interconnect the outputs of multiple AC / DC converters 110a, 110b, it is possible to detect whether changeover switch SW1 is welded without providing a dedicated mechanism. At this time, charging control unit 130 can determine whether changeover switch SW1 has a welded fault while charging vehicle 300.

[0034] 1 illustrates an example in which charging device 100 has two AC / DC converters 110a and 110b and is connected to two charging ports 200a and 200b. However, charging device 100 may have three or more AC / DC converters and be connected to three or more charging ports.

[0035] Although not shown, for example, assume that the charging device 100 has three AC / DC converters 110a, 110b, and 110c, which are connected to three charging ports 200a, 200b, and 200c. In this case, two changeover switches SW1 are disposed between the outputs of each pair of AC / DC converters. The charging device 100 also has three changeover switches SW2a, SW2b, and SW2c connected to the outputs of the three AC / DC converters 110a, 110b, and 110c, respectively. The charging device 100 also has three voltage sensors 120a, 120b, and 120c connected to the outputs of the three AC / DC converters 110a, 110b, and 110c, respectively.

[0036] 2 twice, for example, by sequentially using two of the voltage values ​​VDCa, VDCb, and VDCc detected by the three voltage sensors 120a, 120b, and 120c, thereby enabling the fault detection unit 132 to determine whether or not there is a welding fault in each of the two selector switches SW1.

[0037] 3 twice, sequentially using two of the voltage values ​​VDCa, VDCb, and VDCc detected by the three voltage sensors 120a, 120b, and 120c. This allows the fault detection unit 132 to determine whether or not an open circuit fault and a short circuit fault have occurred in the two selector switches SW1. When the voltage values ​​VDCb and VDCc are used, the symbols DCa and VDCa in the flows of FIGS. 2 and 3 are replaced with DCc and VDCc.

[0038] Although the embodiments for carrying out the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and improvements are possible within the scope that does not depart from the gist of the present invention. [Explanation of symbols]

[0039] 100 Charging device 110a, 110b AC / DC converters 120a, 120b voltage sensors 130 Charging control unit 132 Fault detection unit 200a, 200b charging port 300a, 300b vehicles AC alternating current power supply DCa, DCb DC voltage Ia, Ib charging current SW1, SW2a, SW2b selector switches VDCa, VDCb voltage values

Claims

[Claim 1] a plurality of power converters each converting an AC voltage into a DC voltage; a first switch capable of connecting outputs of a pair of power converters among the plurality of power converters to each other; a plurality of second switches respectively connected between outputs of the plurality of power converters and a plurality of charging ports to which devices to be charged can be respectively connected; a voltage sensor that detects voltage values ​​of a plurality of voltage lines that connect the outputs of the plurality of power converters to the plurality of second switches, respectively; a fault detection unit that detects a welding fault of the first switch when a difference in voltage values ​​of a pair of voltage lines connected to the outputs of the pair of power converters, the voltage values ​​detected by the voltage sensor, is greater than a threshold value, in a state in which the outputs of the pair of power converters outputting DC voltages are connected to each other by the first switch; A charging device comprising:

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