Power supply device with diagnostic function

Abstract

To provide a power supply device with a diagnostic function which can diagnose presence / absence of a failure of a bypass circuit while maintaining power supply to a load.SOLUTION: A power supply device 100 with a diagnostic function comprises: a power supply circuit 10; a bypass circuit 20 one end of which is connected with an input side of the power supply circuit 10, the other end of which is connected with an output side of the power supply circuit 10, and which has an opening / closing switch SW3 for diagnosis, a first voltage detection unit 21, and switches 25, SW4 for bypass operation connected in series; and a control unit 30. The control unit 30 diagnoses connection of the bypass circuit 20 by turning the switches 25, SW4 for bypass operation on in a state of turning the switch SW3 for diagnosis off to measure output side voltage of the power supply circuit 10 by the first voltage detection unit 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply device with a diagnostic function.

Background Art

[0002] In a power supply device, a power supply device capable of performing maintenance of a power supply circuit while maintaining power supply to a load is known.

[0003] For example, Patent Document 1 discloses a power supply device including a power supply circuit, a bypass circuit, and a switching switch that automatically switches between the power supply circuit and the bypass circuit. With such a configuration, it is possible to perform maintenance of the power supply circuit while supplying power to the load via the bypass circuit.

[0004] Also, for example, Patent Document 2 discloses a power supply device including a power supply circuit, a bypass circuit, a switching switch that automatically switches between the power supply circuit and the bypass circuit, and a failure diagnosis function for detecting a failure of the switching switch. With such a configuration, it is possible to supply power to the load via the bypass circuit when the switching switch is in a normal state.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the above power supply device has a problem that it cannot diagnose the presence or absence of a failure such as a disconnection of the bypass circuit while maintaining power supply to the load.

[0007] Therefore, the present invention aims to provide a power supply device with a diagnostic function that can diagnose whether or not there is a fault in the bypass circuit and identify the location of the fault while maintaining power supply to the load. [Means for solving the problem]

[0008] A power supply device with diagnostic function according to one aspect of the present invention is: Power supply circuit and A bypass circuit having a diagnostic switch, a first voltage detection unit, and a bypass operation switch, with one end connected to the input side of the power supply circuit and the other end connected to the output side of the power supply circuit, is connected in series. Control unit and Equipped with, The control unit is characterized by turning on the bypass operation switch while the diagnostic switch is off, and measuring the output voltage of the power supply circuit with the first voltage detection unit to diagnose the connection state of the bypass circuit.

[0009] A power supply device with diagnostic function relating to another aspect of the present invention is: Power supply circuit and A bypass circuit having a diagnostic switch and a bypass switch connected in series, with one end connected to the input side of the power supply circuit and the other end connected to the output side of the power supply circuit, Control unit and Equipped with, The control unit, With all switches except the one being diagnosed turned off, the target switch is turned off and on repeatedly to determine if it has any abnormalities. This process is repeated for all switches. If it is determined that the switch being diagnosed cannot be turned on, the diagnostic process will continue. The diagnostic process is characterized by stopping if it is determined that the switch being diagnosed cannot be turned off due to an abnormality. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a power supply device with a diagnostic function that can diagnose whether or not there is a fault in the bypass circuit and identify the location of the fault while maintaining power supply to the load. [Brief explanation of the drawing]

[0011] [Figure 1] This is a circuit diagram of a power supply device with diagnostic function according to the first embodiment of the present invention. [Figure 2] This is a circuit diagram of a power supply device with diagnostic function according to a second embodiment of the present invention. [Figure 3] This is a flowchart for fault diagnosis of the bypass circuit of the power supply device with diagnostic function according to the first and second embodiments. [Figure 4] This is a flowchart for fault diagnosis of the bypass circuit of the power supply device with diagnostic function according to the third embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. For the sake of clarity, the description of components having the same reference numeral as those already described in the description of the embodiments will be omitted. Furthermore, the dimensions of the components shown in these drawings may differ from the actual dimensions of the components for the sake of clarity.

[0013] (First Embodiment) Figure 1 is a circuit diagram of a power supply device 100 with diagnostic function according to the first embodiment of the present invention. As shown in Figure 1, the power supply device 100 with diagnostic function includes a power supply circuit 10, a bypass circuit 20, a control unit 30, an operation display unit 40, an input terminal T1, and an output terminal T2.

[0014] The power supply circuit 10 is a circuit that converts the AC power input from the AC power source 300 into electrical power and supplies it to the load 400. The power supply circuit 10 includes an input-side switch SW1, a rectifier section 11, a battery 12, an inverter section 13, and an output-side switch SW2. The input-side switch SW1, the rectifier section 11, the inverter section 13, and the output-side switch SW2 are connected in series with each other. The battery 12 is connected to the output node of the rectifier section 11 and the input node of the inverter section 13.

[0015] As shown in FIG. 1, when the input-side switch SW1 is in the ON state, AC power is input from the AC power supply 300 to the rectifier section 11 via the input terminal T1. The rectifier section 11 is composed of a half-wave rectifier circuit, a full-wave rectifier circuit, a smoothing circuit, etc., and converts the input AC power into DC power. During normal operation, the rectifier section 11 supplies DC power to the battery 12 and the inverter section 13. During a power outage, since no AC power is input from the AC power supply 300, the battery 12 supplies DC power to the inverter section 13. The inverter section 13 converts the DC power supplied from the rectifier section 11 or the battery 12 into commercial-frequency AC power. When the output-side switch SW2 is in the ON state, the inverter section 13 supplies AC power to the load 400 via the output terminal T2.

[0016] The bypass circuit 20 is a circuit for supplying the AC power input from the AC power supply 300 to the load 400 by bypassing the power supply circuit 10 when a failure or the like occurs in the power supply circuit 10. By providing the bypass circuit 20, the power supply device 100 with a diagnostic function functions as a non-insulated uninterruptible power supply device.

[0017] The bypass circuit 20 is connected in parallel with the power supply circuit 10, and includes a diagnostic on-off switch SW3, a first bypass operation switch (ACSW) 25, a second bypass operation switch SW4, a first voltage detection unit 21, a second voltage detection unit 22, and a third voltage detection unit 24 (hereinafter, the first voltage detection unit 21, the second voltage detection unit 22, and the third voltage detection unit 24 are also collectively referred to as the voltage detection unit). The diagnostic on-off switch SW3 and the first bypass operation switch 25 are connected in series with each other, and the second bypass operation switch SW4 is connected in parallel with the first bypass operation switch 25. Furthermore, the diagnostic on / off switch SW3 and the second bypass operation switch SW4 may be equipped with auxiliary contacts. Also, the first bypass operation switch 25 is, for example, a semiconductor switch, and the second bypass operation switch SW4 is, for example, a mechanically driven switch, and the two switches operate on different principles.

[0018] The diagnostic switch SW3 is used to diagnose the connection of the bypass circuit 20. The first bypass operation switch 25 and the second bypass operation switch SW4 are switches that allow AC power input from the AC power supply 300 to be supplied to the load 400 via the bypass circuit 20.

[0019] The first bypass switch 25 is controlled on / off by an electrical signal. Therefore, it has a fast response speed but is prone to generating heat. The second bypass switch SW4 is controlled mechanically. Therefore, it has a slow response speed but is less prone to generating heat.

[0020] Using the two switches described above, the control unit 30 switches the path of the AC power input from the AC power supply 300 from the power supply circuit 10 to the bypass circuit 20. Specifically, the control unit 30 first simultaneously sends control signals to the first bypass operation switch 25 and the second bypass operation switch SW4 to turn them ON. As a result, the first bypass operation switch 25 turns ON first, followed by the second bypass operation switch SW4. Once the second bypass operation switch SW4 is ON, the control unit 30 sends a control signal to turn the first bypass operation switch 25 OFF. By controlling the two switches in this procedure, it is possible to prevent the first bypass operation switch 25 from failing due to overheating and to instantly switch the path of the AC power input from the AC power supply 300 from the power supply circuit 10 to the bypass circuit 20.

[0021] The first voltage detection unit 21 is positioned between the diagnostic on / off switch SW3 and the first bypass operation switch 25 and the second bypass operation switch SW4, and measures the voltages on the input and output sides of the power supply circuit 10. The third voltage detection unit 24 is positioned on the output side of the power supply circuit 10, further than the first bypass operation switch 25 and the second bypass operation switch SW4, and measures the voltage on the output side of the power supply circuit 10. The second voltage detection unit 22 is positioned on the input side of the power supply circuit 10, further than the diagnostic on / off switch SW3, and measures the voltage on the input side of the power supply circuit 10.

[0022] As shown in Figure 1, when the diagnostic switch SW3 is ON, AC power is input from the AC power supply 300 to the bypass circuit 20 via the input terminal T1. When the first bypass operation switch 25 or the second bypass operation switch SW4 is ON, the bypass circuit 20 supplies AC power to the load 400 via the output terminal T2.

[0023] As shown in Figure 1, the control unit 30 controls the input switch SW1, rectifier unit 11, inverter unit 13, and output switch SW2 of the power supply circuit 10, as well as the diagnostic on / off switch SW3, first bypass operation switch 25, and second bypass operation switch SW4 of the bypass circuit 20, and measures the voltages of the first voltage detection unit 21, second voltage detection unit 22, and third voltage detection unit 24.

[0024] Specifically, during normal operation other than maintenance of the power supply circuit 10, the control unit 30 turns on the input switch SW1 and the output switch SW2, turns on the diagnostic switch SW3, and turns off the first bypass operation switch 25 and the second bypass operation switch SW4. As a result, the AC power input from the AC power supply 300 is converted into power in the power supply circuit 10 and supplied to the load 400. In the event of a power outage, the control unit 30 turns off the input switch SW1, turns on the output switch SW2, turns off the diagnostic switch SW3, and turns off the first bypass operation switch 25 and the second bypass operation switch SW4. As a result, the DC power input from the battery 12 is converted into power in the power supply circuit 10 and supplied to the load 400.

[0025] Furthermore, when diagnosing the connection of the bypass circuit 20 during normal operation, the diagnostic switch SW3 is turned off, and the first bypass operation switch 25 or the second bypass operation switch SW4 is turned on. The first voltage detection unit 21 measures the voltage on the output side of the power supply circuit 10, and the connection from the first voltage detection unit 21 to the output side of the power supply circuit 10 is confirmed. This allows for diagnosis of whether there are any faults, such as in the connection of the bypass circuit 20, while maintaining power supply to the load 400.

[0026] Furthermore, during maintenance operation, the control unit 30 turns on the diagnostic on / off switch SW3 and the first bypass operation switch 25 or the second bypass operation switch SW4, while turning off the input switch SW1 and the output switch SW2. As a result, the AC power input from the AC power supply 300 is supplied to the load 400 via the bypass circuit 20 without passing through the power supply circuit 10. Therefore, maintenance such as replacing parts of the power supply circuit 10 can be performed.

[0027] The operation display unit 40 receives commands from the user, such as the operating mode, and displays the current operating mode of the diagnostic power supply device 100 and the results of the bypass circuit connection diagnosis. This allows the user to easily understand whether the diagnostic power supply device 100 is operating normally.

[0028] (Second embodiment) Figure 2 is a circuit diagram of a power supply device 200 with diagnostic function according to a second embodiment of the present invention. The power supply device 200 has a configuration in which a maintenance bypass circuit 50 and a changeover switch SW5 are added to the power supply device 100 with diagnostic function according to a first embodiment of the present invention.

[0029] The maintenance bypass circuit 50 is a circuit that supplies AC power input from the AC power supply 300 to the load 400 during maintenance of the bypass circuit 20. By providing the maintenance bypass circuit 50, it is possible to maintain the bypass circuit 20 while maintaining power supply to the load 400.

[0030] The maintenance bypass circuit 50 is connected in parallel with the power supply circuit 10 and the bypass circuit 20, and has a connection switch SW6.

[0031] The changeover switch SW5 is located between the maintenance bypass circuit 50 and the power supply circuit 10 and the bypass circuit 20.

[0032] As shown in Figure 2, the user operates the connection switch SW6 and the changeover switch SW5 of the maintenance bypass circuit 50.

[0033] Specifically, when the bypass circuit 20 is not being maintained (including during maintenance of the power supply circuit 10 and during power outages), the user turns off the connection switch SW6 and turns on the changeover switch SW5. As a result, the AC power input from the AC power supply 300 is converted into power in the power supply circuit 10 or supplied to the load 400 via the bypass circuit 20.

[0034] Furthermore, during maintenance, the user turns on the connection switch SW6 and off the changeover switch SW5. As a result, the AC power input from the AC power supply 300 is supplied to the load 400 via the maintenance bypass circuit 50, without passing through the power supply circuit 10 and the bypass circuit 20, thus allowing maintenance such as replacing parts in the bypass circuit 20 to be performed.

[0035] Furthermore, when diagnosing the connection of the bypass circuit 20 during maintenance operation, the diagnostic switch SW3 is turned off, and the first bypass operation switch 25 or the second bypass operation switch SW4 is turned on. The first voltage detection unit 21 measures the voltage on the output side of the maintenance bypass circuit 50, and the connection from the first voltage detection unit 21 to the output side of the maintenance bypass circuit 50 is confirmed. This allows for diagnosis of any faults, such as connection problems, in the bypass circuit 20 while maintaining power supply to the load 400.

[0036] The configuration and control method of the input-side switch SW1, rectifier unit 11, inverter unit 13, and output-side switch SW2 of the power supply circuit 10, and the diagnostic on / off switch SW3, first bypass operation switch 25, second bypass operation switch SW4, first voltage detection unit 21, second voltage detection unit 22, and third voltage detection unit 24 of the bypass circuit 20, are the same as those of the power supply device with diagnostic function 100 according to the first embodiment of the present invention, so a description will be omitted. (Troubleshooting process flow)

[0037] Figure 3 is a flowchart of fault diagnosis for the bypass circuits of the power supply devices 100 and 200 with diagnostic functions according to the first and second embodiments. First, the control unit 30 determines whether the conditions for starting fault diagnosis are met (S100). Here, the conditions for starting fault diagnosis are that power is being supplied to the load 400 by the power supply circuit 10, the power supply circuit 10 is not in an overload state, the diagnostic on / off switch SW3 is in the ON state, and the second bypass operation switch SW4 and the first bypass operation switch 25 are in the OFF state. In the case of the power supply device with diagnostic function 200 according to the second embodiment, the condition for starting fault diagnosis is also that the connection switch SW6 is in the ON state.

[0038] If the conditions for starting fault diagnosis are met (Yes in S100), the control unit 30 displays on the operation display unit 40 that fault diagnosis can be started (S101) and accepts a command from the user to start the diagnosis (S102). When the user inputs a command to start the diagnosis into the operation display unit 40 (Yes in S102), the control unit 30 executes the diagnostic process from step S103 onwards.

[0039] The control unit 30 turns off the diagnostic on / off switch SW3 (S103). The control unit 30 also measures the voltage using the first voltage detection unit 21 and determines whether the measured voltage is below a predetermined value (S104). If the measured voltage exceeds the predetermined value (No in S104), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is malfunctioning (S118). If the measured voltage is below the predetermined value (Yes in S104), the system proceeds to the next step S105.

[0040] The control unit 30 turns on the diagnostic switch SW3 (S105). The control unit 30 also measures the voltage using the first voltage detection unit 21 and determines whether the measured voltage is above a predetermined value (S106). If the measured voltage is below the predetermined value (No in S106), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is abnormal (S118) and ends the fault diagnosis. If the measured voltage is above the predetermined value (Yes in S106), the control unit 30 turns off the diagnostic switch SW3 (S107) and proceeds to the next step S108.

[0041] The processes from step S103 to step S106 described above allow you to diagnose whether the diagnostic switch SW3 is operating correctly in the on / off state.

[0042] Next, the control unit 30 turns on the second bypass operation switch SW4 (S108). The first voltage detection unit 21 measures the voltage and determines whether the measured voltage is above a predetermined value (S109). If the measured voltage is below the predetermined value (No in S109), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is abnormal (S118) and terminates the fault diagnosis. If the measured voltage is above the predetermined value (Yes in S109), the system proceeds to the next step S110.

[0043] The control unit 30 turns off the second bypass operation switch SW4 (S110). The first voltage detection unit 21 measures the voltage and determines whether the measured voltage is below a predetermined value (S111). If the measured voltage exceeds the predetermined value (No in S111), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is abnormal (S118) and terminates the fault diagnosis. If the measured voltage is below the predetermined value (Yes in S111), the process proceeds to the next step S112.

[0044] The processes from step S108 to step S111 described above allow us to diagnose whether the on / off operation of the second bypass switch SW4 is working correctly.

[0045] Next, the control unit 30 turns on the first bypass operation switch 25 (S112). The first voltage detection unit 21 measures the voltage and determines whether the measured voltage is above a predetermined value (S113). If the measured voltage is below the predetermined value (No in S113), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is abnormal (S118) and terminates the fault diagnosis. If the measured voltage is above the predetermined value (Yes in S113), the system proceeds to the next step S114.

[0046] The control unit 30 turns off the first bypass operation switch 25 (S114). The first voltage detection unit 21 measures the voltage and determines whether the measured voltage is below a predetermined value (S115). If the measured voltage exceeds the predetermined value (No in S115), the control unit 30 displays on the operation display unit 40 that the power supply device with diagnostic function is abnormal (S118) and ends the fault diagnosis. If the measured voltage is below the predetermined value (Yes in S115), the diagnostic on / off switch SW3 is turned on (S116), and on the operation display unit 40 displays that the power supply device with disconnection function is normal (S117) and ends the fault diagnosis.

[0047] The processes from step S112 to step S115 described above allow for diagnosis of whether the on / off operation of the first bypass switch 25 is functioning correctly.

[0048] In this way, with the power supply circuit 10 running, the on / off operation of the diagnostic switch SW3, the first bypass operation switch 25, and the second bypass operation switch SW4, as well as the connections within the bypass circuit 20, can be diagnosed. In other words, it is possible to diagnose whether or not there is a fault in the bypass circuit while maintaining power supply to the load.

[0049] (Third embodiment) Next, we will describe a power supply device 100' with a diagnostic function according to a third embodiment of the present invention. The power supply device 100' with a diagnostic function has the same configuration as the power supply device 100 with a diagnostic function according to the first embodiment of the present invention shown in Figure 1. The fault diagnosis processing flow described below differs from the fault diagnosis processing flow of the first embodiment shown in Figure 3. (Troubleshooting process flow)

[0050] Figure 4 is a flowchart for diagnosing a bypass circuit failure. Steps S200-S206, S208-S210, S212-S215, and S217-S219 in Figure 4 are the same processes as steps S100-S116 in Figure 3, so their explanation is omitted.

[0051] In the third embodiment, in step S206, the control unit 30 determines whether the voltage measured by the first voltage detection unit 21 is equal to or greater than a predetermined value. If the measured voltage is less than the predetermined value (No. in S206), it records an abnormal result that the diagnostic switch SW3 cannot be turned on (S207). After that, the process continues from step S208 without ending the fault diagnosis. This allows the system to diagnose whether the second bypass switch SW4 and the first bypass switch 25 are operating normally, even if an abnormality is detected in the ON operation of the diagnostic switch SW3 (No. in S206).

[0052] Similarly, in step S210, the control unit 30 determines whether the voltage measured by the first voltage detection unit 21 is equal to or greater than a predetermined value. If the measured voltage is less than the predetermined value (No. in S210), it records an abnormal result that the second bypass operation switch SW4 cannot be turned on (S211). After that, the process continues from step S212 onward without ending the fault diagnosis. This allows for diagnosis of whether the second bypass switch SW4 is functioning correctly when it is determined that there is an abnormality in the ON operation (No. in S210), as well as whether the OFF operation of the second bypass switch SW4 and the ON / OFF operation of the first bypass switch 25 are functioning correctly (S213, S215, S218).

[0053] Similarly, in step S215, the control unit 30 determines whether the voltage measured by the first voltage detection unit 21 is equal to or greater than a predetermined value. If the measured voltage is less than the predetermined value (No. in S215), it records an abnormal result that the first bypass operation switch 25 cannot be turned on (S216). After that, the process continues from step S217 onwards without ending the fault diagnosis. This allows for diagnosis (S218) whether the first bypass switch 25 is functioning correctly even if an abnormality is detected in the ON operation of the first bypass switch 25 (No. in S215).

[0054] Furthermore, in step S219, after turning on the diagnostic switch SW3, the control unit 30 determines whether an abnormal result of being unable to turn on each switch has been recorded (S220). If no abnormal result has been recorded (No in S220), the operation display unit 40 displays that the power supply device with diagnostic function is normal (S221). If an abnormal result has been recorded (Yes in S220), the recorded abnormal result is displayed on the operation display unit 40 (S222). Also, in steps S204, S213, and S218, if the measured voltage exceeds a predetermined value (No in S204, S213, and S218), the control unit 30 displays on the operation display unit 40 that one of the diagnostic switch SW3, the second bypass operation switch SW4, or the first bypass operation switch 25 is abnormal (S223). After that, the fault diagnosis is terminated.

[0055] In this manner, the control unit 30 sequentially diagnoses all switches by turning them off and on while all other switches are turned off, and then checking for any abnormalities in the switch being diagnosed. If it determines that the switch being diagnosed cannot be turned on, the diagnostic process continues. If it determines that the switch being diagnosed cannot be turned off, the diagnostic process is terminated. This allows the system to diagnose the on / off operation of the diagnostic switch SW3, the first bypass operation switch 25, and the second bypass operation switch SW4, as well as the connections within the bypass circuit 20, while the power supply circuit 10 is running. If a switch malfunction is detected, the fault location can be identified. In other words, the system can diagnose whether there is a fault in the bypass circuit and identify the fault location while maintaining power supply to the load.

[0056] Although embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be interpreted as being limited by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and the scope of its equivalents.

[0057] For example, as the power supply device with diagnostic function 200' according to the fourth embodiment of the present invention, the fault diagnosis processing flow shown in Figure 4 may be performed with the same configuration as the power supply device with diagnostic function 200 according to the second embodiment of the present invention shown in Figure 2. In this case as well, it is possible to diagnose whether or not there is a fault in the bypass circuit and identify the location of the fault while maintaining power supply to the load.

[0058] Furthermore, in the embodiment of the present invention, the abnormality of the switch to be diagnosed is determined by the voltage detected by the voltage detection unit. However, the abnormality of the switch to be diagnosed may also be determined by the difference in voltages detected by the voltage detection unit (for example, the difference in voltages detected by the first voltage detection unit 21 and the second voltage detection unit 22), or by the state of the auxiliary contacts provided by the diagnostic switching switch SW3 and the second bypass operation switch SW4. [Explanation of Symbols]

[0059] 10 Power supply circuit 11 Rectifier 12 batteries 13. Inverter section 20 Bypass Circuit 21 First voltage detection unit 22 Second voltage detection unit 24 Third voltage detection unit 25. First Bypass Operation Switch (ACSW) 30 Control Unit 40 Operation display section 100, 200, 100', 200' Power supply unit with diagnostic function 300 AC power supply 400 load SW1 Input switch SW2 Output switch SW3 Diagnostic On / Off Switch SW4 Second bypass operation switch SW5 Changeover Switch SW6 Connection Switch T1 Input Terminal T2 Output Terminal

Claims

1. A power supply device with diagnostic functions, A power supply circuit connected to an AC power source, having a battery and an inverter circuit, which outputs AC power to a load, A bypass circuit is provided in parallel with the power supply circuit and outputs the AC power of the AC power supply to the load, bypassing the power supply circuit. Control unit and Equipped with, The bypass circuit has a diagnostic switch, a first voltage detection unit, and a bypass operation switch, all connected in series, with one end connected to the input side of the power supply circuit and the other end connected to the output side of the power supply circuit. The power supply device with a diagnostic function is characterized in that the control unit turns on the bypass operation switch with the diagnostic switch turned off, and measures the output voltage of the power supply circuit with the first voltage detection unit to diagnose the connection state of the bypass circuit.

2. The aforementioned power supply device with diagnostic function is It also features a maintenance bypass circuit. The maintenance bypass circuit has a changeover switch that switches between the power supply circuit and the maintenance bypass circuit. The power supply device with diagnostic function according to claim 1, wherein the control unit switches the changeover switch to the maintenance bypass circuit, turns on the bypass operation switch with the diagnostic on / off switch off, and measures the output voltage of the maintenance bypass circuit with the first voltage detection unit to diagnose the connection state of the bypass circuit.

3. The bypass circuit is A second voltage detection unit is located on the input side of the power supply circuit, which is positioned above the diagnostic switch; The system further includes a third voltage detection unit positioned on the output side of the power supply circuit, which is located further than the bypass switch. The control unit, The power supply device with a diagnostic function according to claim 1, wherein the connection state of the bypass circuit is diagnosed by turning on the bypass operation switch with the diagnostic switch turned off, measuring the difference between the output voltage measured by the third voltage detection unit and the voltage measured by the first voltage detection unit, and turning on the diagnostic switch with the bypass operation switch turned off, measuring the difference between the input voltage measured by the second voltage detection unit and the voltage measured by the first voltage detection unit.

4. A power supply device with diagnostic functions, Power supply circuit and A bypass circuit having a diagnostic switch and a bypass switch connected in series, with one end connected to the input side of the power supply circuit and the other end connected to the output side of the power supply circuit, Control unit and Equipped with, The control unit, With all switches except the one being diagnosed turned off, the target switch is turned off and on repeatedly to determine if it has any abnormalities. This process is repeated for all switches. If it is determined that the switch being diagnosed cannot be turned on, the diagnostic process will continue. A power supply device with a diagnostic function, characterized in that it terminates the diagnostic process if it determines that the switch to be diagnosed cannot be turned off due to an abnormality.

5. The power supply device with diagnostic function according to claim 4, wherein the bypass operation switch is composed of a first bypass operation switch and a second bypass operation switch, each with a different operating principle.

6. The bypass circuit is Voltage detection unit, It further possesses, The voltage detection unit is A first voltage detection unit is positioned between the diagnostic switch and the bypass switch. A second voltage detection unit is located on the input side of the power supply circuit, which is positioned above the diagnostic switch; A third voltage detection unit is located on the output side of the power supply circuit, which is positioned above the bypass switch. Composed of, The power supply device with a diagnostic function according to claim 5, wherein an abnormality in the switch to be diagnosed is determined by the voltage detected by the voltage detection unit, the difference in voltages detected by the voltage detection unit, or the state of the auxiliary contacts provided by the diagnostic switch and the second bypass operation switch.

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