Power Conversion Device

Abstract

To provide a power conversion device capable of more easily checking a tendency in deterioration of a light-emitting element.SOLUTION: There is provided a power conversion device including a main circuit part performing power conversion, a control unit connected to the main circuit part via an optical signal line for communication and controlling the operation of the main circuit part by transmitting / receiving optical signals to / from the main circuit part, and a deterioration tendency confirmation part to enable confirmation of a tendency in deterioration of the main circuit part. The main circuit part includes a light-emitting element for communication to transmit optical signals. The deterioration tendency confirmation part includes a light-emitting element for confirmation to confirm a tendency in deterioration of the light-emitting element for communication of the main circuit part, and can confirm a tendency in deterioration of the light-emitting element for communication based on light output from the light-emitting element for confirmation, by allowing the light-emitting element for confirmation to perform an operation according to the operation of the light-emitting element for communication in an ambient environment according to an ambient environment of the light-emitting element for communication.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a power conversion device. [Background technology]

[0002] There is a power conversion device that includes a main circuit unit that converts power and a control device that controls the operation of the main circuit unit. In power conversion devices that handle relatively large amounts of power, optical components are used to send and receive signals between the main circuit unit and the control device for insulation. The main circuit unit and the control device communicate with each other using a light-emitting element for transmitting optical signals and a light-receiving element for receiving optical signals.

[0003] The light output of a light-emitting element decreases over time due to degradation caused by use. For this reason, power conversion devices using optical components are inspected periodically to measure the light output of the light-emitting element. Light-emitting elements with reduced light output are replaced with new ones before they cause problems in the operation of the power conversion device. This makes it possible to prevent the reduction in light output of the light-emitting element from affecting the operation of the power conversion device.

[0004] The light intensity of the light-emitting element is measured by an operator connecting a light intensity meter to the output terminal of the light-emitting element during inspection of a power conversion device. However, measuring the light intensity of the light-emitting element every time an inspection is performed to check the deterioration trend of the light-emitting element increases the time and cost required for the inspection. Furthermore, inspection requires the operation of the power conversion device to be stopped, which reduces the utilization rate of the power conversion device. For this reason, it is desirable to make it easier to check the deterioration trend of the light-emitting element in a power conversion device that uses optical components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-266662 Summary of the Invention [Problem to be solved by the invention]

[0006] The embodiments of the present invention provide a power conversion device that allows for easier confirmation of the deterioration trend of light-emitting elements. [Means for solving the problem]

[0007] According to an embodiment of the present invention, there is provided a power supply system including: a main circuit unit that converts power; a control device that is connected to the main circuit unit via an optical signal line for communication and that controls the operation of the main circuit unit by sending and receiving optical signals to and from the main circuit unit; and a deterioration tendency confirmation unit that enables confirmation of the deterioration tendency of the main circuit unit. an environment measurement unit that measures the ambient environment of the light-emitting element for communication; and a simulated space generation unit that generates a simulated space that reproduces the ambient environment of the light-emitting element for communication based on the measurement result of the environment measurement unit; the main circuit unit has a communication light emitting element for transmitting an optical signal, and the deterioration tendency checking unit has a checking light emitting element for checking the deterioration tendency of the communication light emitting element of the main circuit unit, By providing the confirmation light-emitting element in the simulated space of the simulated space generating unit, an ambient environment corresponding to the ambient environment of the communication light-emitting element is realized; A power conversion device is provided that makes it possible to check the deterioration trend of the communication light-emitting element based on the light output from the confirmation light-emitting element by making the confirmation light-emitting element operate in accordance with the operation of the communication light-emitting element. [Effects of the Invention]

[0008] A power conversion device is provided that allows the deterioration tendency of light-emitting elements to be more easily confirmed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram schematically illustrating a power conversion device according to a first embodiment. [Figure 2] FIG. 2 is a block diagram schematically illustrating a converter. [Figure 3] 3(a) and 3(b) are graphs schematically showing an example of the operation of the power conversion device according to the first embodiment. [Figure 4] FIG. 4 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. [Figure 5]FIG. 4 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. [Figure 6] FIG. 4 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. [Figure 7] FIG. 10 is a block diagram schematically illustrating a power conversion device according to a second embodiment. [Figure 8] 10 is a graph schematically illustrating an example of the operation of a simulated space generating unit.

[0010] Each embodiment will be described below with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In the present specification and the drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0011] (First embodiment) FIG. 1 is a block diagram schematically illustrating a power conversion device according to a first embodiment. 1, the power conversion device 10 includes a main circuit unit 12, a control device 14, and a deterioration tendency confirmation unit 16. The power conversion device 10 is used, for example, in a DC power transmission system. In the DC power transmission system, the power conversion device 10 is connected to an AC power system and a pair of DC transmission lines.

[0012] The main circuit unit 12 converts power. The main circuit unit 12 is connected to an AC power system, for example, via a transformer (not shown). The AC power of the AC power system is, for example, three-phase AC power. More specifically, it is symmetrical three-phase AC power. The transformer converts the three-phase AC power of the AC power system into AC power compatible with the main circuit unit 12.

[0013] The power conversion device 10 converts three-phase AC power supplied from an AC power system into DC power and supplies the converted DC power to a DC transmission line. The power conversion device 10 also converts DC power supplied from a DC transmission line into three-phase AC power and supplies the converted three-phase AC power to an AC power system. In this way, the power conversion device 10 performs AC-DC conversion from AC to DC and DC to AC.

[0014] The main circuit unit 12 is provided between the AC power system and each DC transmission line. The main circuit unit 12 converts three-phase AC power to DC power and converts DC power back to three-phase AC power. The main circuit unit 12 is, for example, a multilevel power converter having multiple converters 20 connected in series. The main circuit unit 12 is, for example, an MMC (Modular Multilevel Converter) type power converter. Each converter 20 has multiple switching elements connected in half-bridge or full-bridge configuration and a charge storage element connected in parallel to each switching element. The main circuit unit 12 converts power through the operation of the multiple converters 20. The main circuit unit 12 converts AC to DC, for example, by switching each switching element of the multiple converters 20.

[0015] The control device 14 is connected to the main circuit unit 12 via the communication optical signal lines 30 and 31. The control device 14 controls the operation of the main circuit unit 12 by sending and receiving optical signals to and from the main circuit unit 12 via the communication optical signal lines 30 and 31. The control device 14 communicates with the main circuit unit 12 via the communication optical signal lines 30 and 31, and controls the switching of each switching element of each converter 20, thereby controlling the conversion of three-phase AC power to DC power and the conversion of DC power to three-phase AC power by the main circuit unit 12.

[0016] The communication optical signal line 30 is an optical signal line for transmission from the control device 14 to the main circuit unit 12. The communication optical signal line 31 is an optical signal line for transmission from the main circuit unit 12 to the control device 14. In this way, the control device 14 communicates with the main circuit unit 12 via a pair of communication optical signal lines 30, 31. However, the control device 14 may be configured, for example, to transmit optical signals to the main circuit unit 12 and receive optical signals from the main circuit unit 12 using a single communication optical signal line. The configuration of communication between the main circuit unit 12 and the control device 14 is not limited to the above, and may be any configuration that allows optical signals to be transmitted and received between them via at least one communication optical signal line.

[0017] The deterioration tendency checking unit 16 is a device for checking the deterioration tendency of the main circuit unit 12.

[0018] The main circuit section 12 has, for example, a pair of first and second DC terminals 12p, 12n, three AC terminals (first to third) 12a to 12c, and six arms (first to sixth) 22a to 22f.

[0019] The first DC terminal 12p is connected to a high-voltage DC transmission line. The second DC terminal 12n is connected to a low-voltage DC transmission line. As a result, DC power converted by the main circuit unit 12 is supplied to the DC transmission line, and DC power supplied from the DC transmission line is input to the main circuit unit 12.

[0020] The first arm 22a is connected to the first DC terminal 12p. The second arm 22b is connected between the first arm 22a and the second DC terminal 12n. The first arm 22a and the second arm 22b are connected in series between the DC terminals 12p and 12n.

[0021] The third arm 22c is connected to the first DC terminal 12p. The fourth arm 22d is connected between the third arm 22c and the second DC terminal 12n. The third arm 22c and the fourth arm 22d are connected in parallel to the first arm 22a and the second arm 22b.

[0022] The fifth arm 22e is connected to the first DC terminal 12p. The sixth arm 22f is connected between the fifth arm 22e and the second DC terminal 12n. That is, the fifth arm 22e and the sixth arm 22f are connected in parallel to the first arm 22a and the second arm 22b, and are also connected in parallel to the third arm 22c and the fourth arm 22d.

[0023] In this example, the main circuit unit 12 is a three-phase inverter with three legs and six arms. The first arm 22a, the third arm 22c, and the fifth arm 22e are upper arms. The second arm 22b, the fourth arm 22d, and the sixth arm 22f are lower arms. In this manner, the main circuit unit 12 has a plurality of arms and a plurality of legs each formed by a plurality of switching elements. The main circuit unit 12 may be, for example, a single-phase inverter with two legs and four arms. The number of arms and legs is not limited to the above and may be any number.

[0024] Each of the arms 22a to 22f has a plurality of converters 20 connected in series. The number of converters 20 connected in series in each of the arms 22a to 22f is, for example, about 100 to 120. However, the number of converters 20 connected in series is not limited to this and may be any number.

[0025] The number of converters 20 provided in each arm 22a to 22f is substantially the same. For example, when a large number of converters 20 are connected in series, the number of converters 20 provided in each arm 22a to 22f may differ as long as it does not affect the operation of the main circuit unit 12. For example, when 100 converters 20 are connected in series in one arm, the number of converters 20 provided in another arm may differ by one or two.

[0026] In the main circuit section 12, the connection point between the first arm 22a and the second arm 22b, the connection point between the third arm 22c and the fourth arm 22d, and the connection point between the fifth arm 22e and the sixth arm 22f are AC output points.

[0027] First AC terminal 12a is connected to the connection point between first arm 22a and second arm 22b. Second AC terminal 12b is connected to the connection point between third arm 22c and fourth arm 22d. Third AC terminal 12c is connected to the connection point between fifth arm 22e and sixth arm 22f. Each of AC terminals 12a to 12c is connected to an AC power system via a transformer, for example.

[0028] The control device 14 is connected to each of the multiple converters 20 via, for example, multiple optical communication signal lines 30 and 31. The control device 14 controls the operation of each of the multiple converters 20 by communicating with the multiple converters 20 via the multiple optical communication signal lines 30 and 31. Each converter 20 inputs, for example, control signals and protection signals related to control and operational protection of the converter 20 to the control device 14 via the optical communication signal line 31.

[0029] The communication method between the control device 14 and each converter 20 is not limited to the above. For example, multiple converters 20 connected in series may be daisy-chained, and the control device 14 may communicate only with the converter 20 at one end of the daisy-chain and the converter 20 at the other end. The communication method between the control device 14 and each converter 20 may be any communication method that allows appropriate communication between the control device 14 and each converter 20.

[0030] FIG. 2 is a block diagram that schematically illustrates a converter. As shown in FIG. 2, the converter 20 includes a plurality of switching elements 41, 42, a plurality of rectifying elements 43, 44, a plurality of driving circuits 45, 46, a pair of connecting terminals 47, 48, a charge storage element 50, a power supply circuit 51, a voltage detection circuit 52, a control circuit 53, a communication light receiving element 54, and a communication light emitting element 55.

[0031] Each of the switching elements 41, 42 has, for example, a pair of main terminals and a control terminal. Each of the switching elements 41, 42 has an on state and an off state. The on state is a state in which current flows between the pair of main terminals. The off state is a state in which current flow between the pair of main terminals is blocked. Each of the switching elements 41, 42 switches between the on state and the off state depending on the voltage between the pair of main terminals and the voltage of the control terminal. Note that the off state is not limited to a state in which no current flows between the pair of main terminals, but may also be a state in which a weak current flows between the pair of main terminals within a range that does not affect the operation of the main circuit unit 12. Each of the switching elements 41, 42 is, for example, a self-excited semiconductor element such as an IGBT or a MOSFET. However, the switching elements 41, 42 are not limited to this and may be any element that can be arbitrarily switched between an on state and an off state.

[0032] A pair of main terminals of the switching element 42 is connected in series to a pair of main terminals of the switching element 41. In this example, the converter 20 has two switching elements 41 and 42 connected in series. In this example, the converter 20 is a half-bridge converter.

[0033] The rectifying element 43 is connected in anti-parallel to the pair of main terminals of the switching element 41. The forward direction of the rectifying element 43 is opposite to the direction of the current flowing between the pair of main terminals of the switching element 41. Similarly, the rectifying element 44 is connected in anti-parallel to the pair of main terminals of the switching element 42. The rectifying elements 43 and 44 are so-called freewheeling diodes.

[0034] The connection terminal 47 is connected between the switching element 41 and the switching element 42. The connection terminal 48 is connected to the main terminal of the switching element 41 opposite to the main terminal connected to the switching element 42.

[0035] The converters 20 in the same arm are connected in series via a pair of connection terminals 47, 48. Power is supplied to the converters 20 via the connection terminals 47, 48. The switching element 41 is a so-called low-side switch, and the switching element 42 is a so-called high-side switch.

[0036] The control circuit 53 communicates with the control device 14 via the communication optical signal lines 30 and 31, the communication light-receiving element 54, and the communication light-emitting element 55. The control circuit 53 is connected to the communication light-receiving element 54 and the communication light-emitting element 55. The communication light-receiving element 54 is connected to the control device 14 via the communication optical signal line 30. The communication light-receiving element 54 receives an optical signal transmitted from the control device 14, converts the received optical signal into an electrical signal, and inputs it to the control circuit 53. The communication light-emitting element 55 is connected to the control device 14 via the communication optical signal line 31. The communication light-emitting element 55 converts the electrical signal input from the control circuit 53 into an optical signal, and transmits the converted optical signal to the control device 14 via the communication optical signal line 31. This enables transmission and reception of optical signals between the control device 14 and the control circuit 53 of the converter 20.

[0037] The control device 14 transmits control signals for controlling the switching of each of the switching elements 41, 42 as optical signals to the corresponding converters 20 via the communication optical signal line 30. The communication light-receiving element 54 of the converter 20 receives the optical signals transmitted from the control device 14, converts them into control signals that are electrical signals, and inputs them to the control circuit 53. Based on the control signals input from the communication light-receiving element 54, the control circuit 53 inputs drive signals for switching each of the switching elements 41, 42 on and off to the drive circuits 45, 46.

[0038] The drive circuit 45 is connected to a control terminal of the switching element 41. The drive circuit 46 is connected to a control terminal of the switching element 42. The drive circuits 45, 46 switch the on / off of each of the switching elements 41, 42 based on a drive signal input from the control circuit 53. This controls the on / off of each of the switching elements 41, 42 in accordance with a control signal from the control device 14. The control device 14 generates a control signal for each converter 20 and controls the on / off of each of the switching elements 41, 42 of each converter 20. In this way, the control device 14 controls the power conversion by the main circuit unit 12.

[0039] The configurations of the drive circuits 45, 46 and the control circuit 53 are not limited to those described above, and may be any configuration that can control the on / off of each of the switching elements 41, 42. For example, a control signal from the control device 14 may be directly input to the drive circuits 45, 46. In this case, the control circuit 53 can be omitted.

[0040] The charge storage element 50 is connected in parallel to the switching element 41 and the switching element 42. The charge storage element 50 is, for example, a capacitor.

[0041] When switching element 41 is in the OFF state and switching element 42 is in the ON state, the voltage of charge storage element 50 appears between connection terminals 47 and 48. When switching element 41 is in the ON state and switching element 42 is in the OFF state, conduction occurs between connection terminals 47 and 48, and the voltage between connection terminals 47 and 48 becomes substantially zero.

[0042] In this way, the converter 20 switches between an output state in which the voltage of the charge storage element 50 is output between each of the connection terminals 47 and 48, a bypass state in which conduction is established between each of the connection terminals 47 and 48, and a stop state in which each of the switching elements 41 and 42 is turned off, by switching each of the switching elements 41 and 42 based on a control signal from the control device 14.

[0043] In each of the arms 22a to 22f, the total voltage of the converters 20 that are in the output state becomes the voltage of the arm 22a to 22f. The main circuit unit 12 and the control device 14 perform multi-level power conversion by controlling the number of converters 20 that are in the output state.

[0044] When both switching elements 41 and 42 are in the off state (when converter 20 is in the stopped state), the voltage between each connection terminal 47 and 48 is determined by the direction of the arm current. For example, when the arm current flows from connection terminal 48 to connection terminal 47, rectifier element 43 turns on, and the voltage between each connection terminal 47 and 48 becomes substantially zero. Conversely, when the arm current flows from connection terminal 47 to connection terminal 48, rectifier element 44 turns on, charge storage element 50 is charged, and the voltage of charge storage element 50 appears between each connection terminal 47 and 48.

[0045] The power supply circuit 51 is connected in parallel to the charge storage element 50. The power supply circuit 51 generates drive power for the drive circuits 45, 46 and the control circuit 53 based on the charge stored in the charge storage element 50, and supplies the generated drive power to the drive circuits 45, 46 and the control circuit 53. The drive circuits 45, 46 and the control circuit 53 operate in response to the supply of drive power from the power supply circuit 51.

[0046] The method of supplying power to the drive circuits 45, 46 and the control circuit 53 is not limited to the above. For example, power may be supplied to the drive circuits 45, 46 and the control circuit 53 from a power source separate from that of the charge storage element 50. The method of supplying power to the drive circuits 45, 46 and the control circuit 53 may be any method that can appropriately supply power to the drive circuits 45, 46 and the control circuit 53.

[0047] The voltage detection circuit 52 is connected in parallel to the charge storage element 50. The voltage detection circuit 52 is connected to the control circuit 53. The voltage detection circuit 52 detects the DC voltage of the charge storage element 50 and inputs the detected voltage value of the DC voltage of the charge storage element 50 to the control circuit 53.

[0048] The main circuit unit 12 has a communication light-emitting element 55 for transmitting an optical signal to the control device 14 via the communication optical signal line 31. The main circuit unit 12 has a plurality of communication light-emitting elements 55 provided corresponding to the plurality of converters 20, respectively.

[0049] The control circuit 53 of each converter 20 transmits, for example, information required for control to the control device 14 via the communication light-emitting element 55 and the communication optical signal line 31. The control circuit 53 transmits, for example, information indicating the on / off state of each switching element 41, 42, information on the DC voltage of the charge storage element 50 detected by the voltage detection circuit 52, and the like to the control device 14 as information required for control. However, the information transmitted from each converter 20 to the control device 14 is not limited to the above and may be any information. In other words, the optical signal transmitted from each converter 20 to the control device 14 may be any optical signal.

[0050] The deterioration tendency checking unit 16 has a confirmation light-emitting element 60 for checking the deterioration tendency of the communication light-emitting element 55 of the main circuit unit 12. For example, the confirmation light-emitting element 60 is an element having the same model number as the communication light-emitting element 55. For example, a laser diode or a light-emitting diode is used for the communication light-emitting element 55 and the confirmation light-emitting element 60. However, the communication light-emitting element 55 and the confirmation light-emitting element 60 are not limited to the above and may be any element capable of transmitting an optical signal. The confirmation light-emitting element 60 does not necessarily have to be an element having the same model number as the communication light-emitting element 55. The confirmation light-emitting element 60 may be any element that can check the deterioration tendency of the communication light-emitting element 55.

[0051] The deterioration tendency confirmation unit 16 makes the confirmation light-emitting element 60 perform an operation corresponding to the operation of the communication light-emitting element 55 in an ambient environment corresponding to the ambient environment of the communication light-emitting element 55, thereby enabling the deterioration tendency of the communication light-emitting element 55 to be confirmed based on the light output from the confirmation light-emitting element 60.

[0052] The deterioration tendency confirmation unit 16 is provided in the main circuit unit 12 (see FIG. 1). In other words, the deterioration tendency confirmation unit 16 is provided in the vicinity of the main circuit unit 12. The deterioration tendency confirmation unit 16 provides a confirmation light-emitting element 60 in the main circuit unit 12. In other words, the deterioration tendency confirmation unit 16 provides the confirmation light-emitting element 60 in the vicinity of the main circuit unit 12. In this way, the deterioration tendency confirmation unit 16 realizes an ambient environment for the confirmation light-emitting element 60 that corresponds to the ambient environment of the communication light-emitting element 55.

[0053] The ambient environment of the communication light-emitting element 55 includes, for example, the temperature and humidity of the surroundings of the communication light-emitting element 55. For example, the communication light-emitting element 55 and the confirmation light-emitting element 60 tend to deteriorate more easily as the ambient temperature increases. Furthermore, for example, the communication light-emitting element 55 and the confirmation light-emitting element 60 tend to deteriorate more easily as the ambient humidity increases.

[0054] As described above, by providing the confirmation light-emitting element 60 in the main circuit section 12, the temperature and humidity environment around the confirmation light-emitting element 60 can be made closer to the temperature and humidity environment around the communication light-emitting element 55. In other words, the confirmation light-emitting element 60 can be operated in an environment close to the temperature and humidity environment around the communication light-emitting element 55.

[0055] However, the ambient environment of the communication light-emitting element 55 is not limited to temperature and humidity. The ambient environment of the communication light-emitting element 55 may further include other environmental conditions that may affect the deterioration of the communication light-emitting element 55 and the confirmation light-emitting element 60, such as vibration conditions.

[0056] It is more preferable to provide the confirmation light-emitting element 60, for example, near the communication light-emitting element 55. This makes it possible to make the temperature and humidity environment around the confirmation light-emitting element 60 closer to the temperature and humidity environment around the communication light-emitting element 55.

[0057] The deterioration tendency checking unit 16 further includes, for example, a confirmation light receiving element 61 and a drive circuit 62. The confirmation light receiving element 61 is connected to the control device 14 via a confirmation optical signal line 32. The confirmation light emitting element 60 is connected to the control device 14 via a confirmation optical signal line 33. The drive circuit 62 is connected to the confirmation light emitting element 60 and the confirmation light receiving element 61.

[0058] The control device 14 transmits a control signal for controlling the operation of the confirmation light-emitting element 60 as an optical signal to the deterioration trend confirming unit 16 via the confirmation optical signal line 32. The confirmation light-receiving element 61 of the deterioration trend confirming unit 16 receives the optical signal transmitted from the control device 14, converts it into an electrical control signal, and inputs it to the drive circuit 62. The drive circuit 62 operates the confirmation light-emitting element 60 based on the control signal input from the confirmation light-receiving element 61. This allows the confirmation light-emitting element 60 to perform an operation corresponding to the operation of the communication light-emitting element 55 based on the control of the control device 14.

[0059] The operation of the communication light emitting element 55 includes, for example, operating conditions such as the light emitting period and light emitting intensity of the communication light emitting element 55. For example, the drive circuit 62 operates the confirmation light emitting element 60 under the control of the control device 14 for a light emitting period close to the light emitting period of the communication light emitting element 55 and at a light emitting intensity close to the light emitting intensity of the communication light emitting element 55. This allows the confirmation light emitting element 60 to perform an operation corresponding to the operation of the communication light emitting element 55.

[0060] In this way, the deterioration tendency checking unit 16 causes the confirmation light-emitting element 60 to perform an operation corresponding to the operation of the communication light-emitting element 55 in an ambient environment corresponding to the ambient environment of the communication light-emitting element 55. This makes it possible to make the deterioration tendency of the confirmation light-emitting element 60 closer to the deterioration tendency of the communication light-emitting element 55. Therefore, it becomes possible to check the deterioration tendency of the communication light-emitting element 55 based on the light output from the confirmation light-emitting element 60.

[0061] 1, the deterioration tendency checking unit 16 is provided in the main circuit unit 12. For example, the confirmation light receiving element 61 and the drive circuit 62 may be provided at a location away from the main circuit unit 12. In the deterioration tendency checking unit 16, it is sufficient that at least the confirmation light emitting element 60 is provided near the main circuit unit 12 so that the surrounding environment corresponds to the surrounding environment of the communication light emitting element 55.

[0062] Also, in this example, the confirmation light-emitting element 60 is caused to perform an operation corresponding to the operation of the communication light-emitting element 55 under the control of the control device 14. Without being limited to this, for example, an operation corresponding to the operation of the communication light-emitting element 55 may be stored in the drive circuit 62, and the confirmation light-emitting element 60 may be caused to perform an operation corresponding to the operation of the communication light-emitting element 55 based on the driving of the drive circuit 62. In this case, the confirmation optical signal line 32 and the confirmation light-receiving element 61 can be omitted. The confirmation optical signal line 32 and the confirmation light-receiving element 61 are provided as needed and can be omitted.

[0063] The control device 14 is connected to the confirmation light-emitting element 60 via the confirmation optical signal line 33, and checks the amount of light output from the confirmation light-emitting element 60. The control device 14 has, for example, a light-receiving element (not shown), and checks the amount of light output from the confirmation light-emitting element 60 by converting the light output from the confirmation light-emitting element 60 into an electrical signal using the light-receiving element.

[0064] The control device 14 also determines whether the confirmation light-emitting element 60 has deteriorated by, for example, setting a predetermined threshold value for the electrical signal output from the light-receiving element. For example, the control device 14 determines that the confirmation light-emitting element 60 is normal when the electrical signal is equal to or greater than the threshold value, and determines that the confirmation light-emitting element 60 has deteriorated when the electrical signal is less than the threshold value.

[0065] The control device 14 has, for example, a notification unit for notifying a manager or the like of the power conversion device 10 of the confirmation result of the light intensity of the confirmation light-emitting element 60, and notifies the confirmation result by the notification unit. The control device 14 notifies, for example, the determination result of whether or not the confirmation light-emitting element 60 has deteriorated as the confirmation result. This allows the manager or the like of the power conversion device 10 to easily recognize whether or not the confirmation light-emitting element 60 has deteriorated.

[0066] The notification unit is, for example, a display device such as a liquid crystal display. The notification unit may also be, for example, a lamp that turns on and off to notify a manager or the like that the confirmation light-emitting element 60 has deteriorated. The notification unit may be in any manner that can appropriately notify the result of confirmation of the light intensity of the confirmation light-emitting element 60. The notification unit may be any component that can appropriately provide notification.

[0067] It should be noted that the control device 14 does not necessarily have to determine whether the confirmation light-emitting element 60 has deteriorated. For example, the control device 14 may simply report the magnitude of the light intensity of the confirmation light-emitting element 60 (the magnitude of the electrical signal output from the light-receiving element), and leave the determination of whether or not there has been deterioration to an administrator or the like. Furthermore, the control device 14 may be configured to output the confirmation result of the light intensity of the confirmation light-emitting element 60 to an external device such as a higher-level controller. The control device 14 does not necessarily have to have a reporting unit.

[0068] As described above, the power conversion device 10 of this embodiment has a deterioration trend confirmation unit 16, and the deterioration trend confirmation unit 16 has a confirmation light-emitting element 60 for confirming the deterioration trend of the communication light-emitting element 55 of the main circuit unit 12, and by having the confirmation light-emitting element 60 perform an operation corresponding to the operation of the communication light-emitting element 55 in an ambient environment that corresponds to the ambient environment of the communication light-emitting element 55, it is possible to confirm the deterioration trend of the communication light-emitting element 55 based on the light output from the confirmation light-emitting element 60.

[0069] In this way, in the power conversion device 10, it is possible to easily check the deterioration trends of the confirmation light-emitting element 60 and the communication light-emitting element 55 based on the light intensity of the light output from the confirmation light-emitting element 60. This eliminates the need to measure the light intensity of the communication light-emitting element 55 every time an inspection is performed to check the deterioration trend of the communication light-emitting element 55. Only when deterioration of the communication light-emitting element 55 is confirmed based on the light intensity of the confirmation light-emitting element 60, can the light intensity of the communication light-emitting element 55 be measured.

[0070] Therefore, in the power conversion device 10 according to this embodiment, it is possible to more easily check the deterioration tendency of the communication light emitting element 55. For example, it is possible to suppress increases in the time and cost required for inspecting the power conversion device 10. In addition, for example, it is possible to shorten the downtime of the power conversion device 10 due to inspection, thereby improving the utilization rate of the power conversion device 10.

[0071] In the power conversion device 10, the deterioration tendency confirmation unit 16 provides the confirmation light-emitting element 60 in the main circuit unit 12, thereby realizing an ambient environment that corresponds to the ambient environment of the communication light-emitting element 55. As a result, in the power conversion device 10, the ambient environment of the confirmation light-emitting element 60 that corresponds to the ambient environment of the communication light-emitting element 55 can be easily realized without requiring any special equipment or the like to realize the ambient environment.

[0072] In the power conversion device 10, the control device 14 is connected to the confirmation light-emitting element 60 via the confirmation optical signal line 33, and checks the amount of light output from the confirmation light-emitting element 60. This allows the control device 14 to more easily check the deterioration tendency of the confirmation light-emitting element 60 and the communication light-emitting element 55.

[0073] In the MMC type main circuit section 12, the configuration of the converter 20 is not limited to the half-bridge circuit configuration, but may be a full-bridge circuit configuration having four full-bridge-connected switching elements.

[0074] In the above embodiment, an MMC type power converter is used in the main circuit unit 12. The main circuit unit 12 is not limited to the MMC type, and may be, for example, a power converter of another type in which a plurality of converters 20 are connected in series.

[0075] The power conversion device 10 is not limited to DC power transmission systems, but may also be applied to any other system requiring conversion from AC to DC and from DC to AC. The AC-DC conversion by the main circuit unit 12 is not limited to both AC to DC and DC to AC, but may be only AC to DC or DC to AC. The main circuit unit 12 may also be, for example, an AC-AC direct conversion circuit. The power conversion by the main circuit unit 12 may also be conversion from DC power to another DC power, etc. The power conversion by the main circuit unit 12 may be any conversion that converts power into another power.

[0076] The main circuit unit 12 may be configured, for example, with multiple arms in a star connection, delta connection, or matrix connection. The main circuit unit 12 may be, for example, a modular matrix converter. The main circuit unit 12 does not necessarily have to have multiple legs. It is sufficient that the main circuit unit 12 has at least multiple arms. The main circuit unit 12 may be configured in any way that is capable of converting power. The power conversion device may be, for example, a frequency conversion device, a DC transmission device, a reactive power compensator, or a power flow control device.

[0077] The configuration of the main circuit unit 12 is not limited to a configuration in which multiple converters 20 are connected in series, but may be a configuration of a three-phase two-level inverter, etc. The configuration of the main circuit unit 12 may be, for example, a single-phase two-level inverter, a single-phase three-level inverter, a three-phase three-level inverter, etc. The configuration of the main circuit unit 12 is not limited to the above, and may be any configuration that is capable of converting power.

[0078] For example, if the main circuit unit 12 is a three-phase two-level inverter in which six switching elements are full-bridge connected, the main circuit unit 12 has six communication light-receiving elements 54 and communication light-emitting elements 55 corresponding to the six switching elements, respectively. Alternatively, a configuration in which only one communication light-emitting element 55 transmits information required to control the six switching elements to the control device 14 may be used. In this way, the number of communication light-emitting elements 55 provided in the main circuit unit 12 may be any number depending on the configuration of the main circuit unit 12. The number of communication light-emitting elements 55 provided in the main circuit unit 12 may be one.

[0079] On the other hand, if the main circuit unit 12 has multiple converters 20 connected in series and multiple communication light-emitting elements 55 provided corresponding to each of the multiple converters 20, it may take a significant amount of time and money to inspect the multiple communication light-emitting elements 55. For this reason, a configuration such as that of the present application that allows the deterioration trend of the communication light-emitting element 55 to be confirmed based on the light output from the confirmation light-emitting element 60 is considered to be particularly useful in a main circuit unit 12 configuration that has multiple communication light-emitting elements 55. For example, it is possible to more appropriately suppress increases in the time and cost required to inspect the power conversion device 10, and further improve the utilization rate of the power conversion device 10.

[0080] Furthermore, there are cases where the main circuit unit 12 is installed in a location that is difficult to access, such as offshore. The configuration of the present application, which allows the deterioration trend of the communication light-emitting element 55 to be confirmed based on the light output from the confirmation light-emitting element 60, is considered to be particularly useful in such cases. The effect of reducing the time and cost required for inspecting the power conversion device 10 is considered to be particularly significant.

[0081] 3(a) and 3(b) are graphs schematically showing an example of the operation of the power conversion device according to the first embodiment. FIG. 3(a) shows a schematic example of the operation of the communication light emitting element 55. In FIG. FIG. 3(b) shows a schematic example of the operation of the confirmation light emitting element 60. As shown in FIG.

[0082] 3(a) and 3(b), the deterioration tendency checking unit 16 makes the light emitting period of the confirmation light emitting element 60 longer than the light emitting period of the communication light emitting element 55. As a result, the deterioration tendency checking unit 16 makes the operating conditions of the confirmation light emitting element 60 stricter than the operating conditions of the communication light emitting element 55.

[0083] In this way, by setting the operating conditions of the confirmation light emitting element 60 stricter than the operating conditions of the communication light emitting element 55, it is possible to make the deterioration of the confirmation light emitting element 60 occur more quickly than the deterioration of the communication light emitting element 55. This makes it possible to prevent, for example, the deterioration of the communication light emitting element 55 from progressing faster than the deterioration of the confirmation light emitting element 60, which could unintentionally cause malfunction of the main circuit unit 12. This makes it possible to more appropriately check the deterioration trend of the communication light emitting element 55, and more appropriately know the timing for inspection of the communication light emitting element 55 or the timing for component replacement of the communication light emitting element 55.

[0084] When the main circuit unit 12 has a plurality of communication light-emitting elements 55, the operating conditions of the confirmation light-emitting element 60 are set, for example, to be stricter than the strictest operating conditions among the operating conditions of the plurality of communication light-emitting elements 55. For example, the light-emitting period of the confirmation light-emitting element 60 is set to be longer than the longest light-emitting period among the light-emitting periods of the plurality of communication light-emitting elements 55. This makes it possible to more appropriately check the deterioration tendency of the plurality of communication light-emitting elements 55.

[0085] However, the operating conditions of the confirmation light-emitting element 60 do not necessarily have to be stricter than those of the communication light-emitting element 55. The operating conditions of the confirmation light-emitting element 60 may be the same as those of the communication light-emitting element 55.

[0086] The deterioration tendency checking unit 16 may set the operating conditions of the confirmation light-emitting element 60 stricter than those of the communication light-emitting element 55, for example, by making the light intensity of the confirmation light-emitting element 60 greater than that of the communication light-emitting element 55, without being limited to the light-emitting period. The deterioration tendency checking unit 16 sets the operating conditions of the confirmation light-emitting element 60 stricter than those of the communication light-emitting element 55, for example, by adjusting at least one of the light-emitting period and the light intensity. However, the operating conditions of the confirmation light-emitting element 60 are not limited to those described above, and may be any conditions that can be stricter than the operating conditions of the communication light-emitting element 55.

[0087] The deterioration tendency checking unit 16 sets the operating conditions of the confirmation light emitting element 60 based on, for example, a control signal transmitted from the control device 14, thereby making the operating conditions of the confirmation light emitting element 60 stricter than the operating conditions of the communication light emitting element 55. In other words, in this example, the control device 14 makes the operating conditions of the confirmation light emitting element 60 stricter than the operating conditions of the communication light emitting element 55. Without being limited to this, for example, the operating conditions of the confirmation light emitting element 60 may be set in advance in the drive circuit 62 or the like so that they are stricter than the operating conditions of the communication light emitting element 55.

[0088] FIG. 4 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. As shown in Fig. 4, the power conversion device 10a further includes a light quantity measuring device 70. Components that are substantially the same in function and configuration as those in the above embodiment are given the same reference numerals, and detailed description thereof will be omitted. Also, Fig. 4 shows only a portion of the power conversion device 10a corresponding to Fig. 2.

[0089] In the power conversion device 10a, a light quantity meter 70, rather than a control device 14, is connected to the confirmation light-emitting element 60 via a confirmation optical signal line 33. The light quantity meter 70 is connected to the confirmation light-emitting element 60 via the confirmation optical signal line 33, and measures the quantity of light output from the confirmation light-emitting element 60.

[0090] The light quantity meter 70 has, for example, a display unit 72. The light quantity meter 70 measures the quantity of light output from the confirmation light emitting element 60 and displays the measurement result on the display unit 72.

[0091] As a result, in the power conversion device 10a, the deterioration tendency of the confirmation light-emitting element 60 and the communication light-emitting element 55 can be more easily confirmed by the light quantity meter 70. In this way, confirmation of the light quantity of the confirmation light-emitting element 60 may be performed not only by the control device 14 but also by the light quantity meter 70.

[0092] The light quantity meter 70 is not limited to a configuration that displays the measurement result of the light quantity of the confirmation light-emitting element 60, but may be configured, for example, to determine whether the light quantity of the confirmation light-emitting element 60 is equal to or greater than a threshold and notify the determination result. The light quantity meter 70 may be configured to have a notification unit instead of the display unit 72. The light quantity meter 70 may be configured to output, for example, the measurement result of the light quantity of the confirmation light-emitting element 60 or the determination result of whether the light quantity is equal to or greater than a threshold to an external device such as a higher-level controller. The light quantity meter 70 does not necessarily have to have the display unit 72.

[0093] FIG. 5 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. As shown in Fig. 5, in the power electronics device 10b, the deterioration tendency checking unit 16 further includes a checking unit 63 and a communication unit 64. Note that, similar to Fig. 4, Fig. 5 illustrates only a part of the power electronics device 10b corresponding to Fig. 2.

[0094] The confirmation unit 63 confirms the amount of light output from the confirmation light-emitting element 60. For example, the confirmation unit 63 determines whether the amount of light from the confirmation light-emitting element 60 is equal to or greater than a threshold, and inputs the result of the determination to the communication unit 64 as a confirmation result. The confirmation result is, for example, a digital signal that indicates "0" when the amount of light from the confirmation light-emitting element 60 is less than the threshold, and indicates "1" when the amount of light from the confirmation light-emitting element 60 is less than the threshold.

[0095] The communication unit 64 transmits the confirmation result of the confirmation unit 63 to the outside. The communication unit 64 transmits the confirmation result of the confirmation unit 63 to the outside, for example, by wireless communication. The communication unit 64 transmits the confirmation result to the control device 14, for example. In this case, the communication unit 64 may transmit the confirmation result to the control device 14 by optical communication using an optical signal line. The communication unit 64 may transmit the confirmation result to an external device other than the control device 14, such as a higher-level controller or a mobile terminal owned by the administrator of the power conversion device 10b. The external device to which the communication unit 64 transmits the confirmation result is not limited to the above and may be any device that requires the confirmation result of the light intensity of the confirmation light-emitting element 60. The form of communication between the communication unit 64 and the external device may be any form that allows the confirmation result to be appropriately transmitted to the external device.

[0096] In this way, the confirmation of the light intensity of the confirmation light-emitting element 60 may be performed by the deterioration tendency confirmation unit 16, without being limited to an external device such as the control device 14 or the light intensity meter 70. In this case as well, by referring to the confirmation result of the light intensity of the confirmation light-emitting element 60 by the external device, the deterioration tendency of the confirmation light-emitting element 60 and the communication light-emitting element 55 can be more easily confirmed.

[0097] FIG. 6 is a block diagram schematically illustrating a modified example of the power conversion device according to the first embodiment. As shown in FIG. 6, in the power conversion device 10c, the deterioration tendency confirmation unit 16 allows the light output from the confirmation light-emitting element 60 to be visually confirmed from the outside. In this way, the light intensity of the confirmation light-emitting element 60 may be visually confirmed from the outside of the main circuit unit 12 and the deterioration tendency confirmation unit 16 by an administrator of the power conversion device 10c or the like. In this case, too, by visually confirming the light intensity of the confirmation light-emitting element 60, the deterioration tendency of the confirmation light-emitting element 60 and the communication light-emitting element 55 can be more easily confirmed. Note that, as with FIGS. 4 and 5, FIG. 6 illustrates only a portion of the power conversion device 10c corresponding to FIG. 2.

[0098] In this way, the light intensity of the confirmation light-emitting element 60 may be confirmed by the control device 14, by the deterioration tendency confirming unit 16, by the light intensity measuring device 70, or visually. The method for confirming the light intensity of the confirmation light-emitting element 60 is not limited to the above, and any method that can appropriately confirm the light intensity of the confirmation light-emitting element 60 may be used.

[0099] (Second embodiment) FIG. 7 is a block diagram schematically illustrating a power conversion device according to the second embodiment. As shown in FIG. 7, the power conversion device 10d further includes an environment measurement unit 80 and a simulated space generation unit .

[0100] The environment measuring unit 80 measures the ambient environment of the communication light emitting element 55. The environment measuring unit 80 is provided in, for example, the main circuit unit 12, and is arranged near the communication light emitting element 55 of a predetermined converter 20, thereby measuring the ambient environment of the communication light emitting element 55. The environment measuring unit 80 measures, for example, the temperature and humidity around the communication light emitting element 55. However, the measurement targets of the environment measuring unit 80 are not limited to temperature and humidity, and may further include other environmental conditions that may affect the deterioration of the communication light emitting element 55.

[0101] The environment measuring unit 80 transmits the measurement results of the environment surrounding the communication light emitting element 55 to the simulated space generating unit 82. The simulated space generating unit 82 is disposed, for example, outside the main circuit unit 12. The simulated space generating unit 82 may be disposed in any location. The environment measuring unit 80 transmits the measurement results to the simulated space generating unit 82 disposed outside the main circuit unit 12, for example, by wireless communication or optical communication. However, the form of communication between the environment measuring unit 80 and the simulated space generating unit 82 is not limited to the above and may be any form.

[0102] The simulated space generating unit 82 generates a simulated space that reproduces the ambient environment of the communication light-emitting element 55 based on the measurement results of the environment measuring unit 80. The simulated space generating unit 82 generates a simulated space that reproduces the ambient temperature and humidity environment of the communication light-emitting element 55 based on, for example, the measurement results of the environment measuring unit 80. The simulated space generating unit 82 is, for example, a thermostatic bath that can adjust the temperature and humidity inside the bath. However, the simulated space generating unit 82 is not limited to this and may be any device that can reproduce the ambient environment of the communication light-emitting element 55. The simulated space generating unit 82 may be configured with multiple devices, for example, a heater that adjusts the temperature and a humidifier that adjusts the humidity.

[0103] The simulated space generation unit 82 communicates with the environment measurement unit 80 and receives the measurement results of the environment measurement unit 80 from the environment measurement unit 80, thereby generating a simulated space according to the measurement results of the environment measurement unit 80. Without being limited to this, for example, the environment measurement unit 80 may transmit the measurement results to the control device 14, and the simulated space generation unit 82 may communicate with the control device 14 and generate a simulated space according to the measurement results of the environment measurement unit 80 under the control of the control device 14. The method of generating a simulated space according to the measurement results of the environment measurement unit 80 in the simulated space generation unit 82 is not limited to the above, and any method that can appropriately generate a simulated space may be used.

[0104] The deterioration tendency checking unit 16 provides a confirmation light-emitting element 60 in the simulated space of the simulated space generating unit 82, thereby realizing an ambient environment corresponding to the ambient environment of the communication light-emitting element 55. The deterioration tendency checking unit 16 is provided, for example, in the simulated space of the simulated space generating unit 82. However, it is not necessary that the entire deterioration tendency checking unit 16 is disposed in the simulated space, as long as at least the confirmation light-emitting element 60 is disposed in the simulated space.

[0105] The deterioration tendency confirmation unit 16, for example, communicates with the control device 14 and causes the confirmation light-emitting element 60 to perform an operation corresponding to the operation of the communication light-emitting element 55 based on the control of the control device 14. Without being limited to this, the confirmation light-emitting element 60 may also perform an operation corresponding to the operation of the communication light-emitting element 55 by storing the operation in advance.

[0106] In the power conversion device 10d, for example, the control device 14 is connected to the confirmation light-emitting element 60 via the confirmation optical signal line 33, and checks the amount of light output from the confirmation light-emitting element 60. However, similar to the first embodiment, in this example as well, the light amount of the confirmation light-emitting element 60 may be checked by the control device 14, the deterioration tendency checking unit 16, the light amount measuring device 70, or visually.

[0107] As described above, in the power conversion device 10d, the confirmation light-emitting element 60 is provided in the simulated space of the simulated space generating unit 82, thereby realizing an ambient environment that corresponds to the ambient environment of the communication light-emitting element 55. In this case, as in the first embodiment, it is possible to appropriately realize an ambient environment of the confirmation light-emitting element 60 that corresponds to the ambient environment of the communication light-emitting element 55.

[0108] In this way, the confirmation light emitting element 60 does not necessarily have to be provided in the main circuit unit 12. The confirmation light emitting element 60 may be placed in any location that can reproduce the ambient environment of the communication light emitting element 55. Note that, in this example, the main circuit unit 12 may also be configured in any way that converts power, as described in the first embodiment above.

[0109] FIG. 8 is a graph schematically showing an example of the operation of the simulated space generating unit. 8, the simulated space generating unit 82 makes the temperature of the environment surrounding the confirmation light-emitting element 60 higher than the temperature of the environment surrounding the communication light-emitting element 55. In other words, the simulated space generating unit 82 makes the temperature in the simulated space higher than the temperature of the environment surrounding the communication light-emitting element 55. In this way, the simulated space generating unit 82 makes the environment surrounding the confirmation light-emitting element 60 harsher than the environment surrounding the communication light-emitting element 55.

[0110] By providing the confirmation light-emitting element 60 in the simulated space, the deterioration tendency confirmation unit 16 makes the ambient environment of the confirmation light-emitting element 60 harsher than the ambient environment of the communication light-emitting element 55. For example, the deterioration tendency confirmation unit 16 makes the temperature of the ambient environment of the confirmation light-emitting element 60 higher than the temperature of the ambient environment of the communication light-emitting element 55.

[0111] In this way, by making the environment surrounding the confirmation light emitting element 60 more severe than the environment surrounding the communication light emitting element 55, it is possible to make the deterioration of the confirmation light emitting element 60 occur more quickly than the deterioration of the communication light emitting element 55. This makes it possible to prevent, for example, the communication light emitting element 55 from deteriorating faster than the confirmation light emitting element 60, which could unintentionally cause malfunction of the main circuit unit 12. This makes it possible to more appropriately check the deterioration trend of the communication light emitting element 55, and more appropriately know the timing for inspection of the communication light emitting element 55 or the timing for component replacement of the communication light emitting element 55.

[0112] In addition, the simulated space generating unit 82 may make the environment surrounding the confirmation light-emitting element 60 harsher than the environment surrounding the communication light-emitting element 55, for example, by making the humidity of the environment surrounding the confirmation light-emitting element 60 higher than the humidity of the environment surrounding the communication light-emitting element 55.

[0113] The method of making the environment surrounding the confirmation light-emitting element 60 harsher than that surrounding the communication light-emitting element 55 is not limited to the above, and any method may be used. For example, a heater may be provided around the confirmation light-emitting element 60 to make the temperature of the environment surrounding the confirmation light-emitting element 60 higher than that of the environment surrounding the communication light-emitting element 55, thereby making the environment surrounding the confirmation light-emitting element 60 harsher than that surrounding the communication light-emitting element 55. In this way, the method of making the environment surrounding the confirmation light-emitting element 60 harsher than that surrounding the communication light-emitting element 55 is not limited to the operation of the simulated space generating unit 82.

[0114] For example, when adjusting the surrounding environment of the confirmation light-emitting element 60 by providing a heater around the confirmation light-emitting element 60, as described in the first embodiment above, in a configuration in which the confirmation light-emitting element 60 is provided in the main circuit section 12, the surrounding environment of the confirmation light-emitting element 60 may be made harsher than the surrounding environment of the communication light-emitting element 55.

[0115] In addition, the deterioration tendency confirmation unit 16 may make the ambient environment of the confirmation light-emitting element 60 harsher than the ambient environment of the communication light-emitting element 55, and further, as described with respect to Figure 3, may make the operating conditions of the confirmation light-emitting element 60 harsher than the operating conditions of the communication light-emitting element 55.

[0116] In the above-described embodiments, an example is shown in which the deterioration trend of the communication light-emitting element 55 for transmitting an optical signal to the control device 14 via the communication optical signal line 31 is confirmed based on the light output from the confirmation light-emitting element 60. The object for which the deterioration trend is confirmed by the confirmation light-emitting element 60 is not limited to the communication light-emitting element 55 for communication with the control device 14. For example, a communication light-emitting element may be used for communication within the main circuit unit 12, such as when optical communication is performed between multiple converters 20 in the main circuit unit 12. In such a case, the deterioration trend of the communication light-emitting element used for communication within the main circuit unit 12 may be confirmed by the light output from the confirmation light-emitting element 60. The object for which the deterioration trend is confirmed by the confirmation light-emitting element 60 is not limited to the above, and may be any communication light-emitting element provided in the main circuit unit 12 that transmits an optical signal.

[0117] The present embodiment includes the following aspects. (Appendix 1) a main circuit section that converts power; a control device connected to the main circuit unit via an optical signal line for communication, and configured to control the operation of the main circuit unit by transmitting and receiving optical signals to and from the main circuit unit; a deterioration tendency confirmation unit for confirming the deterioration tendency of the main circuit unit; Equipped with the main circuit unit has a communication light emitting element for transmitting an optical signal, The deterioration trend confirmation unit has a confirmation light-emitting element for confirming the deterioration trend of the communication light-emitting element of the main circuit unit, and by having the confirmation light-emitting element perform an operation corresponding to the operation of the communication light-emitting element in an ambient environment that corresponds to the ambient environment of the communication light-emitting element, the power conversion device makes it possible to confirm the deterioration trend of the communication light-emitting element based on the light output from the confirmation light-emitting element.

[0118] (Appendix 2) The power conversion device according to claim 1, wherein the deterioration tendency confirmation unit provides the confirmation light-emitting element in the main circuit unit, thereby realizing an ambient environment corresponding to the ambient environment of the communication light-emitting element.

[0119] (Appendix 3) an environment measurement unit that measures the surrounding environment of the communication light emitting element; a simulated space generating unit that generates a simulated space that reproduces the ambient environment of the communication light-emitting element based on the measurement result of the environment measuring unit; Furthermore, The power conversion device according to claim 1, wherein the deterioration tendency confirmation unit provides the confirmation light-emitting element within the simulated space of the simulated space generation unit, thereby realizing an ambient environment corresponding to the ambient environment of the communication light-emitting element.

[0120] (Appendix 4) The power conversion device according to any one of appendices 1 to 3, further comprising a light intensity meter connected to the confirmation light-emitting element via a confirmation optical signal line and measuring the amount of light output from the confirmation light-emitting element.

[0121] (Appendix 5) The power conversion device according to any one of appendices 1 to 3, wherein the control device is connected to the confirmation light-emitting element via a confirmation optical signal line and confirms the amount of light output from the confirmation light-emitting element.

[0122] (Appendix 6) The power conversion device according to any one of appendices 1 to 3, wherein the deterioration tendency confirmation unit further includes a confirmation unit that confirms the amount of light output from the confirmation light-emitting element, and a communication unit that transmits the confirmation result of the confirmation unit to an external device.

[0123] (Appendix 7) 4. The power conversion device according to claim 1, wherein the deterioration tendency checking unit allows the light output from the checking light emitting element to be visually checked from the outside.

[0124] (Appendix 8) 8. The power conversion device according to claim 1, wherein the deterioration tendency checking unit sets stricter operating conditions for the checking light emitting element than operating conditions for the communication light emitting element.

[0125] (Appendix 9) 9. The power conversion device according to claim 1, wherein the deterioration tendency checking unit makes the ambient environment of the checking light emitting element more severe than the ambient environment of the communication light emitting element.

[0126] (Appendix 10) The power conversion device according to any one of appendices 1 to 9, wherein the main circuit unit has a plurality of converters connected in series, converts power by the operation of the plurality of converters, and has a plurality of the communication light-emitting elements provided corresponding to each of the plurality of converters.

[0127] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0128] 10, 10a to 10d... power conversion device, 12... main circuit section, 12p, 12n... DC terminal, 12a to 12c... AC terminal, 14... control device, 16... deterioration tendency confirmation section, 20... converter, 22a to 22f... arm, 30, 31... optical signal line for communication, 32, 33... optical signal line for confirmation, 41, 42... switching element, 43, 44... rectifier element, 45, 46... drive circuit, 47, 48... connection terminal, 50... charge storage element, 51... power supply circuit, 52... voltage detection circuit, 53... control circuit, 54... light receiving element for communication, 55... light emitting element for communication, 60... light emitting element for confirmation, 61... light receiving element for confirmation, 62... drive circuit, 63... confirmation section, 64... communication section, 70... light amount meter, 72...display section, 80...environment measurement section, 82...simulated space generation section

Claims

1. a main circuit section that converts power; a control device connected to the main circuit unit via an optical signal line for communication, and configured to control the operation of the main circuit unit by transmitting and receiving optical signals to and from the main circuit unit; a deterioration tendency confirmation unit for confirming the deterioration tendency of the main circuit unit; an environment measurement unit that measures the surrounding environment of the communication light emitting element; a simulated space generating unit that generates a simulated space that reproduces the ambient environment of the communication light-emitting element based on the measurement result of the environment measuring unit; Equipped with the main circuit unit has a communication light emitting element for transmitting an optical signal, The deterioration trend confirmation unit has a confirmation light-emitting element for confirming the deterioration trend of the communication light-emitting element of the main circuit unit, and by providing the confirmation light-emitting element within the simulated space of the simulated space generation unit, an ambient environment corresponding to the ambient environment of the communication light-emitting element is realized, and by having the confirmation light-emitting element perform an operation corresponding to the operation of the communication light-emitting element, the deterioration trend of the communication light-emitting element can be confirmed based on the light output from the confirmation light-emitting element, thereby forming a power conversion device.

2. a main circuit section that converts power; a control device connected to the main circuit unit via an optical signal line for communication, and configured to control the operation of the main circuit unit by transmitting and receiving optical signals to and from the main circuit unit; a deterioration tendency confirmation unit for confirming the deterioration tendency of the main circuit unit; Equipped with the main circuit unit has a communication light emitting element for transmitting an optical signal, The deterioration trend confirmation unit has a confirmation light-emitting element for confirming the deterioration trend of the communication light-emitting element of the main circuit unit, and by making the surrounding environment of the confirmation light-emitting element more severe than the surrounding environment of the communication light-emitting element and causing the confirmation light-emitting element to perform an operation corresponding to the operation of the communication light-emitting element, the power conversion device makes it possible to confirm the deterioration trend of the communication light-emitting element based on the light output from the confirmation light-emitting element.

3. 2. The power conversion device according to claim 1, further comprising a light quantity meter connected to the confirmation light emitting element via a confirmation optical signal line, for measuring the quantity of light output from the confirmation light emitting element.

4. 2. The power conversion device according to claim 1, wherein the control device is connected to the confirmation light emitting element via a confirmation optical signal line and checks the amount of light output from the confirmation light emitting element.

5. The power conversion device according to claim 1 , wherein the deterioration tendency confirmation unit further includes a confirmation unit that confirms the amount of light output from the confirmation light-emitting element, and a communication unit that transmits the confirmation result of the confirmation unit to an external device.

6. The power conversion device according to claim 1 , wherein the deterioration tendency checking unit allows the light output from the checking light emitting element to be visually checked from the outside.

7. The power conversion device according to claim 1 , wherein the deterioration tendency checking unit sets stricter operating conditions for the checking light emitting element than operating conditions for the communication light emitting element.

8. 2. The power conversion device according to claim 1, wherein the main circuit unit has a plurality of converters connected in series, converts power by operation of the plurality of converters, and has a plurality of the communication light-emitting elements provided corresponding to each of the plurality of converters.

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