Relay failure detection system

Abstract

To provide a relay failure detection system that enables charging to be started or ended accurately at a date and time desired by a user.SOLUTION: In a relay failure detection system housed in charging equipment for an electric vehicle and mounted on a power switching module, a relay is arranged in a power switching module on a power line between the AC input and the outlet output to the electric vehicle, and the relay failure detection system includes a conversion unit that switches between outputting a HIGH signal or a LOW signal when the absolute value of the relay output that is output to the outlet output is greater than or equal to a predetermined threshold value or less than the threshold value depending on the open / closed state of the relay, and a determination unit that determines whether the operation of the relay is normal or abnormal on the basis of an opening / closing command signal to the relay and the output signal of the conversion unit.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a relay failure detection system for detecting whether a relay is operating normally or abnormally. [Background technology]

[0002] Conventionally, there is known a device for diagnosing a fault in a relay that can switch the power supply from a power source from on to off or from off to on. An example of a relay fault is a fault that makes the above switching impossible. In addition, the above device can be applied to, for example, the drive control of a vehicle (see Patent Documents 1 to 3, for example).

[0003] In recent years, in order to popularize electric vehicles (EVs), basic charging has been developed to allow EVs to be charged in places where EVs usually stay for long periods of time, such as parking lots. When starting or ending charging, a relay included in a module in the charging device is controlled to be turned on or off, and at this time, it is desirable for the relay to be switched on or off accurately as desired by the user. In other words, it is required that the relay be accurately turned on and off to supply power to the storage battery in the EV according to the charging time specified by the user. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5018081 [Patent Document 2] Patent No. 5434388 [Patent Document 3] Patent No. 7028135 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology disclosed herein has been made to solve the above problems, and its purpose is to provide a technology that can detect relay failure with greater accuracy, so as to enable charging to be started or ended accurately at the date and time desired by the user. [Means for solving the problem]

[0006] The present disclosure for solving the above problems provides a relay failure detection system that is installed in a power switching module that is housed in a charging facility for an electric vehicle and has a function of switching power supplied to the electric vehicle, measuring the power, and communicating with an external device, the relay failure detection system comprising: a relay is disposed in the power line between the AC input and the outlet output to the electric vehicle in the power switching module; a conversion unit that switches between a HIGH signal and a LOW signal depending on whether the absolute value of the relay output output to the outlet is equal to or greater than a predetermined threshold value or is less than the threshold value; a determination unit that determines whether the operation of the relay is normal or abnormal based on an opening / closing command signal to the relay and an output signal from the conversion unit; The present invention includes a relay failure detection system comprising:

[0007] In this disclosure, it is assumed that the power switching module is housed in a charging facility installed in a location where basic charging is possible, such as a parking lot of an apartment building. By applying the power switching module to charging an EV and using a relay failure detection system, it is possible to charge the EV as planned by the user. An example of a specific flow is as follows. First, the user connects the EV to the outlet output and sets the charging schedule for the EV using a terminal such as a smartphone. This completes the charging reservation, and when the date and time for charging to start arrives, the control unit issues a command to turn on the relay (close command). Similarly, when the date and time for charging to end arrives, the control unit issues a command to turn off the relay (open command).

[0008] At this time, the user can know whether the relay is operating normally or abnormally by checking the output signal of the conversion unit in response to the determination unit issuing a command to turn the relay on or off. If the relay is operating abnormally, the user can know that an abnormality has occurred in that the EV is not being charged during the time period set for charging, or that the EV is still being charged after the date and time set for charging to end has passed. In this way, by using the relay failure detection system according to the present disclosure and checking the instruction from the control unit to the relay and the output signal from the conversion unit, it is possible to detect whether the relay is operating normally or abnormally. This makes it possible to accurately start or end charging the EV at the date and time desired by the user, and as a result, it is possible to prevent undercharging and overcharging. In addition to the above-mentioned EV, the electric vehicle in this disclosure also includes an electrically assisted bicycle, an electric kickboard, an electric wheelchair, a robotic lawnmower, and the like.

[0009] In the present disclosure, the determination unit may determine that the operation of the relay is normal if the output signal of the conversion unit is a pulse train signal with a predetermined cycle when the open / close command signal of the relay is a close command. In the present disclosure, the determination unit may determine that the operation of the relay is abnormal if the output signal of the conversion unit continues to be a HIGH signal or a LOW signal for a predetermined period longer than the predetermined cycle when the open / close command signal of the relay is a close command. This makes it possible to determine whether the operation of the relay is normal / abnormal through easier processing. The output signal may also be transmitted to a user's terminal, and this allows the user to easily and instantly know whether the operation of the relay is normal or abnormal when the open / close command signal of the relay is a close command.

[0010] In the present disclosure, the determination unit may determine that the operation of the relay is abnormal if the output signal of the conversion unit is a pulse train signal with a predetermined cycle when the switching command signal of the relay is an open command. In the present disclosure, the determination unit may determine that the operation of the relay is normal if the output signal of the conversion unit continues to be a HIGH signal or a LOW signal for a predetermined period longer than the predetermined cycle when the switching command signal of the relay is an open command. This also makes it possible to determine whether the operation of the relay is normal / abnormal by easier processing. And, even when the switching command signal of the relay is an open command, the user can easily and instantly know whether the operation of the relay is normal or abnormal.

[0011] In the present disclosure, the conversion unit may include a photocoupler having a light source that emits light according to the outlet output and a switching element that turns on when the amount of light from the light source is equal to or greater than a predetermined amount. The photocoupler is an element that can transmit an electrical signal while electrically isolating two systems of power lines driven by independent power sources, and this makes it possible to insulate and separate the power circuit related to the power line from the AC input to the EV from the digital circuit including the judgment unit and the like, thereby making it possible to reduce the risk of electric shock and the like during maintenance of the digital circuit side.

[0012] In addition, in the present disclosure, when the operation of the relay is abnormal, a signal indicating the abnormality may be transmitted to the external device by the communication function. For example, the device may be a management device (or management system) for the entire charging control of an EV. In this way, measures can be taken quickly to maintain normal charging control, such as replacing relays or power switching modules.

[0013] In the present disclosure, the power switching module may include a plurality of relays, and when an operation of any one of the relays is determined to be abnormal, the switching command signal of the other relays may be set as an open command, thereby making it possible to stop the power supply via the other relays.

[0014] The above means for solving the problems can be used in combination with each other whenever possible. Effect of the Invention

[0015] According to the technology disclosed herein, it is possible to more accurately detect relay failures in a power switching module of an electric vehicle charging facility. As a result, it is possible to accurately start or end charging according to a user's request, and it is possible to maintain the normal functioning of the electric vehicle charging facility. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram illustrating an example in which a relay failure detection system according to an embodiment is applied to charging an EV. [Diagram 2] FIG. 2 is a schematic diagram illustrating a configuration of a relay failure detection system according to an embodiment. [Diagram 3] 3A to 3C are diagrams illustrating the relationship between the presence or absence of an electrical signal transmitted to the MCU according to the embodiment and the presence or absence of a square wave output to the MCU. [Figure 4] Fig. 4A is a schematic diagram showing a state in which power is supplied to an EV from a charging facility (pole) that houses a power switching module provided in a relay failure detection system according to an embodiment. Fig. 4B is a perspective view showing a portion surrounded by a dashed line in Fig. 4A in a see-through manner. Fig. 4C is a diagram showing a state in which the power switching module according to an embodiment is installed on a wall. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] [Application example] An outline of an application example of the present disclosure will be described below with reference to some of the drawings. FIG. 1 is a block diagram showing an example in which a relay failure detection system 1 according to this application example is applied to charging an EV 2. The relay failure detection system 1 according to this application example is mounted on a power switching module 10, which is a module involved in managing charging power in a charging device. In addition to the relay failure detection system 1, the power switching module 10 is configured to include a relay 100, a part of a control unit 101 (the control unit 101 has a part that is included as part of the relay failure detection system 1), a power measurement unit 102, and the like.

[0018] The relay 100 is connected to an AC power source 11 such as a commercial power supply system. In addition, the relay 100 switches from an ON (closed state) to an OFF (open state) or from an OFF (open state) to an ON (closed state) state upon receiving a command signal from a control unit 101. When an AC current is input from the AC power source 11 to the relay 100 in the ON state, the AC current is output to the EV charging outlet 12 via a power measurement unit 102 that measures power. This allows the EV 2 to be charged by connecting the charging cable of the EV 2 to the EV charging outlet 12. The state in which power is supplied from the power switching module 10 to the EV is shown in FIG. 4A, which will be described later.

[0019] 2 is a schematic diagram showing the configuration of the relay failure detection system 1 according to this application example. One end of the capacitor 13 is connected to the relay 100 through which an AC current flows from the relay 100 to the EV charging outlet 12. The AC power source 11 is connected to a power line, and a part of this AC current passes through the capacitor 13 and resistor R1 and reaches the photocoupler 14. The capacitor 13 has insulating properties and meets a predetermined safety standard. The photocoupler 14 has two parallel LEDs (light-emitting diodes) 141 and a photodiode 142, and the AC signal from the AC power source 11 causes the LED 141 to emit light whether it is positive or negative with respect to a PE (Protective Earth: security ground), and turns on the photodiode 142 when the amount of light is equal to or greater than a threshold. As a result, a pulse train signal (rectangular wave) having a frequency twice that of the AC power source 11 is output from the photocoupler 14. Here, the LED 141 corresponds to a light source in this disclosure, and the photodiode 142 corresponds to a switching element in this disclosure.

[0020] The AC electrical signal is transmitted to an MCU (Micro Controller Unit) 16, and a square wave is applied to a port (not shown) of the MCU 16. The MCU 16 determines whether the relay 100 is normal or abnormal based on the relationship between a command signal provided to the relay 100 from the control unit 101 and the output signal of the photocoupler 14. Details will be described later with reference to Figures 3A to 3C.

[0021] [Example] Hereinafter, a relay failure detection system 1 according to an embodiment of the present disclosure will be described in more detail with reference to the drawings (including the drawings once described in the above application example). Note that the relay failure detection system 1 according to the embodiment of the present disclosure is not intended to be limited to the following configuration.

[0022] <Configuration> Returning now to the explanation of Fig. 1, as described above, the power switching module 10 according to this embodiment has a function of switching AC power by the relay 100, a function of measuring AC power by the power measuring unit 102, and a wireless communication function by the control unit 101.

[0023] The control unit 101 uses a wireless communication function to send information required for charge management to the upper charge management system 3. The control unit 101 also uses the wireless communication function to receive instructions from the charge management system 3, and sends a command signal for opening and closing control to the relay 100 in response to the instructions. The control unit 101 also calculates the amount of power usage based on the power measured by the power measurement unit 102.

[0024] The above functions enable the user to charge the EV 2 during a desired time period. The dashed arrows in FIG. 1 indicate the flow of data via wireless communication by LTE (Long Term Evolution). The wireless communication allows only specific users to access the charging management system 3 and also enables data communication between a specific control unit 101 and the charging management system 3, thereby improving the security of the charging management system 3. The wireless communication function may be exercised even when the user charges the EV 2 without inputting a charging schedule.

[0025] 1 shows a single relay 100 for simplicity, but in this embodiment, a plurality of relays 100 may be arranged in the power switching module 10. Then, as described later, when it is determined that the operation of any one of the relays 100 is abnormal, the control unit 101 may transmit a command signal so that the other relays 100 are turned off. This makes it possible to stop the power supply via the other relays when an abnormality occurs in some of the relays.

[0026] In the relay failure detection system 1 according to the present embodiment, one EV charging outlet 12 In contrast, the above-mentioned function of switching AC power, function of measuring AC power, and wireless communication function are packaged together as a power switching module 10. Therefore, for example, if an abnormality is found in the relay 100, it is possible to easily manage these functions for each EV charging outlet 12 by replacing the entire power switching module 10.

[0027] In addition, in this embodiment, the battery of the EV2 is exemplified as the object to be charged, but the object to be charged in the present disclosure is not limited to this, and may be, for example, other electric vehicles such as an electrically assisted bicycle, an electric kick scooter, an electric wheelchair, a robotic lawnmower, etc. Furthermore, rechargeable electrical products other than electric vehicles may be the object to be charged.

[0028] Returning to the explanation of Fig. 2, in the circuit system shown in Fig. 2, relay 100 and capacitor 13 may be used that have life spans as close as possible. This makes it possible to replace capacitor 13 together with a new relay included in the new power switching module when replacing power switching module 10 with a new one, thereby suppressing the inefficiency of using each element separately.

[0029] In addition, the photocoupler 14 has a property of electrically insulating two different power lines, and therefore can electrically isolate a circuit portion that handles large power from the AC power source 11 to the EV charging outlet 12 from a circuit portion related to the MCU 16. This can reduce the risk of electric shock when performing maintenance on the MCU 16, etc. Here, the photocoupler 14 is one of the components of the conversion unit in this disclosure. Also, the MCU 16 is included in the control unit 101. In this embodiment, the power supply voltage of the constant voltage power supply 15 connected to the resistors R2 and R3 may be 3.3 V.

[0030] Next, a process for detecting whether the operation of the relay 100 is normal or abnormal will be described with reference to Fig. 3A to Fig. 3C. Each of Fig. 3A to Fig. 3C shows the relationship between the ON state (closed state) or OFF state (open state) of the relay 100 and the output of the photocoupler 14. When the operation of the relay 100 is normal, as shown in Fig. 3A, no square wave is output from the photocoupler 14 while the command signal to the relay 100 is in the LOW state (open command), and when the command signal to the relay 100 becomes the HIGH state (close command), a square wave of a constant frequency is output. This is because, as described above, when the relay is in the normal state and becomes in the closed state in accordance with the command signal, an AC signal from the AC power source 11 is input to the photocoupler 14, and a pulse train signal is output from the photocoupler 14.

[0031] 3B and 3C show the relationship between the command signal of the relay 100 and the output of the photocoupler 14 when an abnormality occurs in the operation of the relay 100. In FIG. 3B, a square wave of a constant frequency is output while the command signal to the relay 100 is in a HIGH state, and the operation of the relay 100 is normal. However, even if the command signal to the relay 100 is in a LOW state, the square wave continues to be output, and this state can be used to determine that the operation of the relay 100 is abnormal. Note that this abnormality occurs because the contact surface of the relay 100 melts and adheres, causing the relay 100 to maintain an ON state, even though the control unit 101 controls the relay 100 to be in an OFF state. Also, in FIG. 3C, while the command signal to the relay 100 is in a LOW state, no square wave is output, and the operation of the relay 100 is normal. However, even if the command signal to the relay 100 is in a HIGH state, no square wave is output, and this state can be used to determine that the operation of the relay 100 is abnormal. That is, this abnormality occurs because the relay 100 maintains its OFF state even though the control unit 101 controls the relay 100 to be ON. Whether the command signal of the relay 100 is in the HIGH state or the LOW state is determined by the magnitude relationship between the absolute value of the output of the relay 100 and a predetermined threshold value. Also, whether the operation of the relay 100 is normal or abnormal is determined by the absolute value of the output of the relay 100 and a predetermined threshold value. The determination as to whether the state is normal is performed by a determination unit in the present disclosure, which is included in the control unit 101.

[0032] The determination of whether the output of the photocoupler 14 is a square wave or not is based on whether the output of the photocoupler 14 continues to be in a HIGH or LOW state for a period that is sufficiently long with respect to the period of the square wave. Since the period of the square wave in this embodiment is about 10 msec as described later, in this embodiment, for example, when the sampling time of the output signal is 1 msec, it is determined whether the output of the photocoupler 14 is in a HIGH state for 30 msec or more. If the output of the photocoupler 14 is in a HIGH state for 30 msec or more, it is determined that the relay 100 is in an OFF state (open state) in the circuit shown in FIG. 2. If the output of the photocoupler 14 does not continue to be in a HIGH state for 30 msec, it is determined that the output of the photocoupler 14 is a square wave and the relay 100 is in an ON state (closed state) in the circuit shown in FIG. 2. Depending on the circuit configuration shown in FIG. 2, it goes without saying that the logic of HIGH and LOW of the output of the photocoupler 14 may be reversed in determining whether the output of the photocoupler 14 is a square wave or not.

[0033] 3B and 3C, when an abnormality occurs in the operation of the relay 100, a signal indicating the abnormality may be transmitted to the charge management system 3 using the communication function of the control unit 101. This enables the entire system to quickly take measures such as replacing the relay 100 or the power switching module 10.

[0034] Next, an example of the input specifications of the MCU 16 shown in FIG. 3A in this embodiment will be described. In this embodiment, the low pulse width LW, which is the period from the end of output of one pulse in a square wave to the start of output of the next pulse, is 2 msec or more. The high pulse width HW, which is the period from the start of output of one pulse in a square wave to the start of output of the next pulse, is 10 msec (converted to a frequency of 100 Hz) when the frequency of the AC power supply 11 is 50 Hz, and is 8.3 msec (converted to a frequency of 120 Hz) when the frequency of the AC power supply 11 is 60 Hz. The width of the square wave corresponds to the difference between HW and LW. In addition, the height of the square wave is 3.3 V, which is the power supply voltage of the constant voltage power supply 15. The same applies to the input specifications of the MCU 16 shown in FIG. 3B.

[0035] FIG. 4A is a schematic diagram showing a state in which power is supplied to an EV2 from a charging facility (pole) that houses a power switching module 10 provided in a relay failure detection system 1 according to this embodiment. In this embodiment, power is supplied to an EV2 from a power switching module 10 housed inside a pole in, for example, a parking lot of an apartment building. This charging method corresponds to basic charging, which charges the EV2 during times when the EV2 is not in use, and since charging can be done over a long period of time, it is possible to reduce the load on the battery of the EV2. In addition, since each person charges the EV2 by connecting a cord to an EV charging outlet 12, it is possible to charge only when necessary. In addition, the cost of installing the power switching module 10 for basic charging is relatively low.

[0036] In this embodiment, basic charging is exemplified as the charging method, but even if other charging methods are used, it is possible to introduce the power switching module 10 and supply power to the EV 2. Other charging methods include destination charging, in which charging is performed at a facility at the destination, and route charging, in which charging is performed on the way to the destination.

[0037] Fig. 4B is a perspective view showing the part surrounded by the dashed line in Fig. 4A in a see-through manner. Specifically, it is a diagram showing the power switching module 10 housed inside a pole. Since it is housed inside a pole, the power switching module 10 itself does not need to be waterproof or weatherproof.

[0038] The power switching module 10 may be mounted not only inside the pole but also in any other place as shown in FIG. As shown in the figure, the relay failure detection system 1 may be housed inside a wall-mounted pool box and installed on a wall. In this way, by expanding the locations where the power switching module 10 is installed, it is possible to increase the penetration rate of the power switching module 10, and it becomes possible to apply the relay failure detection system 1 in various fields.

[0039] In addition, in order to make it possible to compare the constituent elements of the present disclosure with the configurations of the examples, the constituent elements of the present disclosure will be described below with the reference numerals in the drawings.

[0040] <Appendix 1> A relay failure detection system (1) is mounted on a power switching module (10) that is housed in a charging facility for an electric vehicle (2) and has a function of switching power supplied to the electric vehicle, measuring the power, and communicating with an external device (3), a relay (100) is disposed in the power line between an AC input and a power outlet output (12) to the electric vehicle in the power switching module; a conversion unit (14) that switches between a HIGH signal and a LOW signal depending on whether the absolute value of the relay output output to the outlet output is equal to or greater than a predetermined threshold value or is less than the threshold value in response to an open / closed state of the relay; a determination unit that determines whether the operation of the relay is normal or abnormal based on an opening / closing command signal to the relay and an output signal from the conversion unit; A relay failure detection system (1) comprising: [Explanation of symbols]

[0041] 1. Relay failure detection system 10....Power switching module 100···Relay 101...Control section 102 Power measurement unit 11...AC power supply 12. EV charging outlet 13. Capacitor 14 Photocoupler 141 LED 142 Photodiode 15 Constant voltage power supply 16...MCU 2. EV 3. Charging management system

Claims

1. A relay failure detection system that is installed in a power switching module that is housed in a charging facility for an electric vehicle and has a function of switching power supplied to the electric vehicle, measuring the power, and communicating with an external device, comprising: a relay is disposed in the power line between the AC input and the outlet output to the electric vehicle in the power switching module; a conversion unit that switches between a HIGH signal and a LOW signal depending on whether an absolute value of a relay output output to the outlet output is equal to or greater than a predetermined threshold value or is less than the threshold value in response to an open / closed state of the relay; a determination unit that determines whether the operation of the relay is normal or abnormal based on an opening / closing command signal to the relay and an output signal from the conversion unit; A relay failure detection system comprising:

2. 2. The relay failure detection system according to claim 1, wherein the determination unit determines that the operation of the relay is normal if the output signal of the conversion unit is a pulse train signal having a predetermined period when the opening / closing command signal of the relay is a closing command.

3. 2. The relay failure detection system according to claim 1, wherein the determination unit determines that the operation of the relay is abnormal if the output signal of the conversion unit continues to be a HIGH signal or a LOW signal for a predetermined period longer than the predetermined cycle when an opening / closing command signal for the relay is a closing command.

4. 2. The relay failure detection system according to claim 1, wherein the determination unit determines that the operation of the relay is abnormal if the output signal of the conversion unit is a pulse train signal having a predetermined period when the opening / closing command signal of the relay is an opening command.

5. 2. The relay failure detection system according to claim 1, wherein the determination unit determines that the operation of the relay is normal if the output signal of the conversion unit continues to be a HIGH signal or a LOW signal for a predetermined period longer than the predetermined cycle when an opening / closing command signal for the relay is an opening command.

6. 2. The relay failure detection system according to claim 1, wherein the conversion unit includes a photocoupler having a light source that emits light in response to the outlet output and a switching element that is turned on when the amount of light from the light source is equal to or greater than a predetermined amount.

7. 2. The relay failure detection system according to claim 1, wherein, when an operation of the relay is abnormal, a signal indicating that the operation of the relay is abnormal is transmitted to the external device by the communication function.

8. 2. The relay failure detection system according to claim 1, wherein a plurality of the relays are arranged in the power switching module, and when it is determined that the operation of any one of the relays is abnormal, the switching command signal of the other relays is set as an open command.

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