Power conversion device

Abstract

To provide a power conversion device capable of easily detecting abnormality in a transmission path before allowing a main circuit part to operate power conversion.SOLUTION: Provided is a power conversion device comprising: a main circuit part for converting power; and a control device connected to the main circuit part via a transmission path to control operation of the main circuit part by transmitting an instruction signal to the main circuit part via the transmission path and receiving a response signal transmitted from the main circuit part as a response to the instruction signal via the transmission path. The control device has: a signal generation unit for generating a simulated instruction signal corresponding to the instruction signal when the main circuit part stops an operation of power conversion, and transmitting the simulated instruction signal to the main circuit part via the transmission path; and a detection circuit for detecting abnormality of the transmission path if a response signal corresponding to the simulated instruction signal is not transmitted from the main circuit part when the simulated instruction signal is transmitted to the main circuit part.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. The control device is connected to the main circuit unit via a transmission path and controls the operation of the main circuit unit by transmitting command signals such as control command signals and protection command signals to the main circuit unit via the transmission path.

[0003] In such a power conversion device, if the main circuit unit is operated when there is an abnormality in the transmission path, it may become impossible to control the operation of the main circuit unit normally, which could lead to a malfunction of the main circuit unit.

[0004] For example, if an abnormality occurs in the transmission path of a protection command signal that causes the main circuit section to perform a protection operation, even if some abnormality occurs in the device and an attempt is made to cause the main circuit section to perform a protection operation, the main circuit section will not be able to perform the protection operation properly, and there is a concern that an extensive failure will occur in the main circuit section.

[0005] Furthermore, for example, if an abnormality occurs in the transmission path of the control command signal for controlling the power conversion operation of the main circuit section, the power conversion operation of the main circuit section cannot be controlled properly, and there is a concern that components such as switching elements used in the main circuit section may be damaged.

[0006] Although it is possible to have workers inspect the transmission path, inspecting the path every time the power conversion operation of the main circuit is stopped is time-consuming for the workers. For this reason, it is desirable for a power conversion device to be able to easily detect abnormalities in the transmission path before the main circuit performs power conversion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-254017 Summary of the Invention [Problem to be solved by the invention]

[0008] An embodiment of the present invention provides a power conversion device that can easily detect an abnormality in a transmission path before causing a main circuit unit to perform a power conversion operation. [Means for solving the problem]

[0009] According to an embodiment of the present invention, there is provided a power conversion device comprising: a main circuit section that converts power; and a control device connected to the main circuit section via a transmission path, that transmits a command signal to the main circuit section via the transmission path, and that controls operation of the main circuit section by receiving, via the transmission path, a response signal transmitted from the main circuit section in response to the command signal, wherein the control device has: a signal generation section that generates a simulated command signal corresponding to the command signal when the main circuit section has stopped its power conversion operation, and transmits the simulated command signal to the main circuit section via the transmission path; and a detection circuit that detects an abnormality in the transmission path when the response signal corresponding to the simulated command signal is not transmitted from the main circuit section even when the simulated command signal is transmitted to the main circuit section. [Effects of the Invention]

[0010] A power conversion device is provided that can easily detect an abnormality in a transmission path before causing a main circuit section to perform a power conversion operation. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram schematically illustrating a power conversion device according to an embodiment. [Figure 2] FIG. 2 is a block diagram schematically illustrating a part of a control device according to an embodiment. [Figure 3]FIG. 2 is a block diagram schematically illustrating a part of a control device according to an embodiment. [Figure 4] FIG. 10 is a block diagram schematically illustrating a modified example of the power conversion device according to the embodiment.

[0012] 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.

[0013] FIG. 1 is a block diagram schematically illustrating a power conversion device according to an embodiment. As shown in FIG. 1, the power conversion device 10 includes a main circuit unit 12 and a control device 14.

[0014] The main circuit unit 12 converts power. The main circuit unit 12 has, for example, multiple switching elements and converts power by switching the multiple switching elements. The main circuit unit 12 converts, for example, at least one of DC power to AC power and AC power to DC power. The power conversion by the main circuit unit 12 may be conversion from DC power to another DC power, or conversion from AC power to another AC power, etc. The power conversion operation by the main circuit unit 12 may be any operation that converts power into another power. The main circuit unit 12 may be configured in any way that can appropriately convert power.

[0015] The control device 14 controls the operation of the main circuit unit 12. The control device 14 is connected to the main circuit unit 12 via a pair of control transmission paths 16a, 16b and a pair of protection transmission paths 18a, 18b. The control device 14 transmits a control command signal for controlling the power conversion operation of the main circuit unit 12 to the main circuit unit 12 via the control transmission path 16a. The control device 14 also transmits a protection command signal for causing the main circuit unit 12 to perform a protection operation to the main circuit unit 12 via the protection transmission path 18a.

[0016] The main circuit unit 12 converts power based on a control command signal transmitted from the control device 14. The control command signal is, for example, a pulse signal for switching between the on state and the off state of a switching element in the main circuit unit 12. The control command signal may also be called, for example, a gate command.

[0017] In this way, when the control command signal is a pulse signal for switching the on state and off state of a switching element, a pair of control transmission paths 16a, 16b is provided, for example, for each of the multiple switching elements of the main circuit unit 12. The control device 14, for example, generates multiple control command signals corresponding to each of the multiple switching elements of the main circuit unit 12, and transmits the generated multiple control command signals to the main circuit unit 12 via the multiple control transmission paths 16a.

[0018] The control command signal may be, for example, a command value indicating the magnitude of power to be output from the main circuit unit 12. The pulse signal may be generated on the main circuit unit 12 side based on, for example, a command value input from the control device 14. In this case, the number of control transmission paths 16a, 16b may be one each. The configuration of the control device 14 and the pair of control transmission paths 16a, 16b may be any configuration that can appropriately control the power conversion operation by the main circuit unit 12.

[0019] The main circuit unit 12 converts the power based on the control command signal transmitted from the control device 14, and then transmits a control response signal to the control device 14 via the control transmission path 16b in response to the control command signal.

[0020] The control response signal is, for example, a signal that indicates the state of operation of power conversion based on the control command signal. In other words, the control response signal is a state signal that indicates the state of operation of the main circuit unit 12. For example, if the control command signal is a pulse signal for switching the on state and off state of a switching element, the control response signal is a signal that indicates the on state and off state of the switching element.

[0021] This allows the control device 14 to determine whether the main circuit unit 12 is operating normally. For example, if the control response signal indicates that the switching element is on when the control command signal has set the switching element to the off state, the control device 14 can determine that the switching element has a short-circuit failure. In this case, the control device 14, for example, stops the power conversion operation of the main circuit unit 12.

[0022] Furthermore, for example, if the control command signal is a command value indicating the magnitude of power, the control response signal may be a signal indicating that the control command signal has been received. The control response signal is not limited to the above, and may be any signal that responds to the reception of a control command signal.

[0023] The main circuit unit 12 performs a protection operation based on a protection command signal transmitted from the control device 14. The protection operation is, for example, an operation to stop the operation of power conversion. The protection operation may also be, for example, an operation to cause a protection device that protects the equipment of the main circuit unit 12 to protect the equipment. The protection device is, for example, an overvoltage suppression device that suppresses overvoltage of switching elements, charge storage elements, etc. The protection operation is not limited to the above and may be any operation related to the protection of the main circuit unit 12.

[0024] The main circuit unit 12 performs a protection operation based on the protection command signal transmitted from the control device 14, and then transmits a protection response signal to the control device 14 via the protection transmission path 18b in response to the protection command signal.

[0025] The protection response signal is, for example, a signal indicating the stop of the power conversion operation based on the protection command signal. In other words, the protection response signal is a stop signal indicating the stop of the power conversion operation of the main circuit unit 12. This allows the control device 14 to know whether or not the main circuit unit 12 has performed a protection operation.

[0026] The protection response signal may be, for example, a signal indicating the operation of a protection device. The protection response signal may be, for example, a signal indicating that a protection command signal has been received. The protection response signal is not limited to the above and may be any signal that responds to the reception of a protection command signal.

[0027] In this way, the control device 14 is connected to the main circuit unit 12 via transmission paths such as the control transmission paths 16a and 16b and the protection transmission paths 18a and 18b, and controls the operation of the main circuit unit 12 by transmitting command signals such as control command signals and protection command signals to the main circuit unit 12 via the transmission paths and receiving response signals such as control response signals and protection response signals transmitted from the main circuit unit 12 in response to the command signals via the transmission paths. The control device 14 controls the operation of the main circuit unit 12, for example, by generating the next command signal in response to the transmitted response signal.

[0028] The command signal is not limited to a control command signal and a protection command signal, but may be any command signal for controlling the operation of the main circuit unit 12. The response signal is not limited to a control response signal and a protection response signal, but may be any response signal transmitted from the main circuit unit 12 to the control device 14 in response to a command signal. The response signal may also be called, for example, an answerback signal. The pair of transmission paths is not limited to the control transmission paths 16a, 16b and the protection transmission paths 18a, 18b, but may be any transmission path used for transmitting any command signal and any response signal. The number of transmission paths may be any number. The number of transmission paths may be set appropriately depending on the number of command signals and response signals to be transmitted. For example, if one transmission path can be commonly used for transmitting command signals and response signals, the number of transmission paths may be one.

[0029] Transmission paths such as the control transmission paths 16a, 16b and the protection transmission paths 18a, 18b are configured, for example, by a communication device on the control device 14 side that transmits and receives signals, a communication device on the main circuit unit 12 side that transmits and receives signals, and a signal line connecting the communication devices. The transmission paths may transmit, for example, electrical signals. The transmission paths may also transmit, for example, optical signals. The signal lines may be optical signal lines such as optical fibers. Each communication device may be configured, for example, to convert between electrical signals and optical signals. In this way, transmitting optical signals can ensure insulation between the main circuit unit 12 and the control device 14 and enable high-speed signal transmission and reception between the main circuit unit 12 and the control device 14. Furthermore, the transmission paths may include, for example, wireless communication in part. The transmission paths may be configured in any manner that enables the transmission of command signals and response signals between the main circuit unit 12 and the control device 14.

[0030] The transmission path transmits the command signal and the response signal by switching between, for example, a first state in which the voltage is low and a second state in which the voltage is higher than the first state. In other words, the transmission path transmits the command signal and the response signal by digital communication. The first state is, for example, a low state, and the second state is, for example, a high state. In the case of optical communication, the first state is, for example, an off state, and the second state is, for example, an on state.

[0031] The control command signal, for example, sets the off state of the switching element as a first state and the on state of the switching element as a second state. As a result, the main circuit unit 12 can switch the on state and off state of the switching element based on the control command signal. The protection command signal, for example, switches from the first state to the second state when a protection operation is to be performed. As a result, the main circuit unit 12 can perform a protection operation in response to the protection command signal switching from the first state to the second state. However, the modes of the command signal and the response signal are not limited to those described above and may be any mode that allows the content of the signal to be transmitted appropriately.

[0032] FIG. 2 is a block diagram schematically illustrating a part of the control device according to the embodiment. As shown in FIG. 2, the control device 14 includes an actual signal generating unit 30, a simulation signal generating unit 32, an OR circuit 34, and a detection circuit 36.

[0033] The actual signal generating unit 30 generates an actual protection command signal while the main circuit unit 12 is performing a power conversion operation. The actual signal generating unit 30 generates the actual protection command signal based on, for example, a control response signal transmitted from the main circuit unit 12 or a command from a higher-level controller. For example, when the actual signal generating unit 30 detects a short-circuit fault in a switching element based on the control response signal or when it receives a command to stop the main circuit unit 12 from a higher-level controller or operation panel, the actual signal generating unit 30 generates the actual protection command signal by switching the output voltage from a voltage corresponding to a first state of the protection command signal to a voltage corresponding to a second state. The actual signal generating unit 30 is connected to an OR circuit 34 and inputs the generated actual protection command signal to the OR circuit 34.

[0034] The simulation signal generating unit 32 generates a simulated protection command signal corresponding to an actual protection command signal when the main circuit unit 12 stops power conversion operation. For example, when starting up the main circuit unit 12, the simulation signal generating unit 32 generates a simulated protection command signal by switching the output voltage from a voltage corresponding to a first state of the protection command signal to a voltage corresponding to a second state before starting up the main circuit unit 12. The time to start up the main circuit unit 12 is, more specifically, when switching the main circuit unit 12 from a state in which power conversion operation is stopped to a state in which power conversion operation is performed.

[0035] The simulation signal generating unit 32 may, for example, constantly generate a simulated protection command signal when the power conversion operation of the main circuit unit 12 is stopped by switching the output voltage from a voltage corresponding to the first state of the protection command signal to a voltage corresponding to the second state when the power conversion operation of the main circuit unit 12 is stopped.

[0036] The simulation signal generating unit 32 may periodically generate a simulated protection command signal when the power conversion operation of the main circuit unit 12 is stopped, for example, by periodically switching the output voltage between a voltage corresponding to the first state of the protection command signal and a voltage corresponding to the second state when the power conversion operation of the main circuit unit 12 is stopped.

[0037] The simulation signal generating unit 32 may, for example, receive an input of an external signal, and when the power conversion operation of the main circuit unit 12 stops, generate a simulated protection command signal based on the input of the external signal by switching the output voltage from a voltage corresponding to the first state of the protection command signal to a voltage corresponding to the second state based on the input of the external signal.

[0038] The external signal is input to the simulation signal generating unit 32, for example, from an operation unit connected to the simulation signal generating unit 32. That is, the simulation signal generating unit 32 may be configured so that the timing for generating a simulated protection command signal can be manually set by an administrator of the power conversion device 10 or the like operating the operation unit.

[0039] Furthermore, the external signal may be input to the simulation signal generator 32 from an external device by, for example, communicating with the external device. The external device may be, for example, a higher-level controller or a terminal of an administrator of the power conversion device 10. That is, the simulation signal generator 32 may generate a simulated protection command signal based on the control of or operation of the external device.

[0040] The simulation signal generating unit 32 is connected to the OR circuit 34 and inputs the generated simulation protection command signal to the OR circuit 34.

[0041] The OR circuit 34 is connected to the protection transmission path 18a and the detection circuit 36. The OR circuit 34 transmits the input actual protection command signal or simulated protection command signal to the main circuit unit 12 via the protection transmission path 18a, and also inputs the signal to the detection circuit 36.

[0042] When the actual protection command signal is generated by the actual signal generating unit 30, the control device 14 transmits the actual protection command signal to the main circuit unit 12 and, for example, executes protection interlocking processing. The protection interlocking processing is, for example, processing to notify a higher-level controller or the like of the execution of a protection operation, or to open a switch on the input side or output side of the main circuit unit 12. On the other hand, when the control device 14 generates a simulated protection command signal by the simulated signal generating unit 32, the control device 14 does not execute protection interlocking processing. This makes it possible to prevent, for example, the simulated protection command signal from being transmitted to a higher-level controller or the like, which then executes a protection operation.

[0043] In this way, the control device 14 is provided with the actual signal generating unit 30, the simulated signal generating unit 32, and the OR circuit 34 so that the protection linkage process is performed only when an actual protection command signal is generated. However, the configuration of the control device 14 is not limited to this, and may be configured such that a single signal generating unit generates an actual protection command signal and a simulated protection command signal. The configuration of the control device 14 may be any configuration that can appropriately generate an actual protection command signal and a simulated protection command signal. The OR circuit 34 and the like are provided as needed and can be omitted.

[0044] The main circuit unit 12 performs a protection operation in response to input of an actual protection command signal or a simulated protection command signal, and transmits a protection response signal to the control device 14 via the protection transmission path 18b. For example, the main circuit unit 12 may be configured to determine whether the signal is an actual protection command signal or a simulated protection command signal. For example, when the main circuit unit 12 receives a simulated protection command signal, the main circuit unit 12 may not perform a protection operation, but may transmit a simulated protection response signal equivalent to a case in which a protection operation is performed to the control device 14 via the protection transmission path 18b.

[0045] The detection circuit 36 ​​receives an input of the simulated protection command signal from the OR circuit 34, and also receives an input of the protection response signal (including the simulated protection response signal) transmitted from the main circuit unit 12. The detection circuit 36 ​​detects an abnormality in the protected transmission paths 18a, 18b based on the input simulated protection command signal and protection response signal.

[0046] The detection circuit 36 ​​detects an abnormality in the protection transmission paths 18a, 18b when a protection response signal corresponding to the simulated protection command signal is not transmitted from the main circuit unit 12 even when the simulated protection command signal is transmitted to the main circuit unit 12. The detection circuit 36 ​​detects an abnormality in the protection transmission paths 18a, 18b, for example, when the protection response signal does not become a state indicating that the protection operation has been performed (for example, a high voltage state) even when the simulated protection command signal becomes a state instructing the execution of a protection operation (for example, a high voltage state). In other words, the detection circuit 36 ​​detects an abnormality in the protection transmission paths 18a, 18b when a mismatch occurs between the state of the simulated protection command signal and the state of the protection response signal.

[0047] FIG. 3 is a block diagram schematically illustrating a part of the control device according to the embodiment. As shown in FIG. 3, the control device 14 further includes a signal generating unit 40 and a detection circuit 42.

[0048] The signal generating unit 40 generates an actual control command signal when the main circuit unit 12 is performing power conversion operation, and also generates a simulated control command signal corresponding to the actual control command signal when the main circuit unit 12 is stopping its power conversion operation.

[0049] The signal generating unit 40 generates actual control command signals based on commands from a higher-level controller while the main circuit unit 12 is performing power conversion. As described above, the control command signals include pulse signals for switching the on and off states of the switching elements of the main circuit unit 12, command values ​​representing the magnitude of the power to be output from the main circuit unit 12, and the like.

[0050] The simulated control command signal may be a pulse signal for switching the on and off states of the switching elements of the main circuit unit 12, or may be a signal of a command value indicating the magnitude of the power output from the main circuit unit 12. The simulated control command signal may be any signal corresponding to an actual control command signal.

[0051] Similar to the simulation signal generation unit 32, the signal generation unit 40 generates a simulated control command signal, for example, when starting up the main circuit unit 12 and before starting up the main circuit unit 12. Similar to the simulation signal generation unit 32, the signal generation unit 40 may generate a simulated control command signal constantly when the power conversion operation of the main circuit unit 12 is stopped, may generate a simulated control command signal periodically, or may generate a simulated control command signal based on the input of an external signal.

[0052] The signal generating unit 40 transmits the generated actual control command signal or simulated control command signal to the main circuit unit 12 via the control transmission path 16a, and also inputs the signal to the detection circuit 42.

[0053] The main circuit unit 12 includes a switching element 50 and a drive circuit 52. The switching element 50 has a pair of main terminals and a control terminal, and has an ON state in which a current flows between the pair of main terminals, and an OFF state in which the current flowing between the pair of main terminals is interrupted. The switching element 50 may be, for example, an IGBT or a MOSFET. The drive circuit 52 switches the ON state and OFF state of the switching element 50 based on a control command signal transmitted from the control device 14.

[0054] The main circuit unit 12 has, for example, a plurality of switching elements 50 and a plurality of drive circuits 52, and switches the on and off states of each switching element 50 based on a control command signal transmitted from the control device 14. As a result, the main circuit unit 12 performs a power conversion operation so as to output power of a magnitude corresponding to the control command signal, for example.

[0055] Furthermore, the drive circuit 52 switches the on / off state of the switching element 50 based on the control command signal transmitted from the control device 14, generates a control response signal, and transmits the generated control response signal to the control device 14 via the control transmission path 16b. The drive circuit 52 generates a control response signal that indicates, for example, the on / off state of the switching element. However, as described above, the control response signal is not limited to this and may be any signal that responds to the reception of a control command signal.

[0056] The detection circuit 42 receives the simulated control command signal from the signal generation unit 40 and also receives the control response signal transmitted from the main circuit unit 12. The detection circuit 42 detects abnormalities in the control transmission paths 16a and 16b based on the input simulated control command signal and control response signal.

[0057] The detection circuit 42 detects an abnormality in the control transmission paths 16a, 16b when a simulated control command signal is transmitted to the main circuit unit 12 but a control response signal corresponding to the simulated control command signal is not transmitted from the main circuit unit 12. The detection circuit 42 detects an abnormality in the control transmission paths 16a, 16b, for example, when the simulated control command signal is in a state that switches the switching element 50 to the on state (for example, a high voltage state) but the control response signal is not in a state that indicates that the switching element 50 has been switched to the on state (for example, a high voltage state). In other words, the detection circuit 42 detects an abnormality in the control transmission paths 16a, 16b when a mismatch occurs between the state of the simulated control command signal and the state of the control response signal.

[0058] When the detection circuit 36 ​​detects an abnormality in the protection transmission paths 18a, 18b, and when the detection circuit 42 detects an abnormality in the control transmission paths 16a, 16b, the control device 14 outputs, for example, a detection of an abnormality.

[0059] The control device 14 causes the notification unit to issue a notification regarding the detection of an abnormality, for example, by outputting a detection of an abnormality to the notification unit. The notification unit may be, for example, a display device that issues a notification by displaying characters or patterns, a speaker that issues a notification by outputting sound, or an indicator light that issues a notification by emitting light, etc. However, the configuration of the notification unit is not limited to the above, and any configuration that can appropriately issue a notification of the detection of an abnormality may be used.

[0060] The control device 14 may output a signal indicating the detection of an abnormality to an external device, such as a higher-level controller or a terminal of a manager of the power conversion device 10. By outputting the detection of an abnormality to a notification unit or an external device in this way, it is possible to notify the higher-level controller, the manager of the power conversion device 10, or the like of the occurrence of an abnormality in the control transmission paths 16a, 16b or the protection transmission paths 18a, 18b.

[0061] As described above, in the control device 14 of the power conversion device 10 according to this embodiment, the simulated signal generating unit 32 generates a simulated protection command signal when the main circuit unit 12 stops power conversion operation, and the detection circuit 36 ​​detects an abnormality in the protection transmission paths 18a, 18b for transmitting the protection command signal based on the input simulated protection command signal and protection response signal.

[0062] As a result, the power conversion device 10 according to this embodiment can detect an abnormality in the protection transmission paths 18a, 18b before causing the main circuit unit 12 to perform power conversion. Therefore, for example, when some abnormality occurs in the device and the main circuit unit 12 is actually caused to perform a protection operation, it is possible to prevent the main circuit unit 12 from properly performing the protection operation due to an abnormality in the protection transmission paths 18a, 18b, and prevent an expanded failure from occurring in the main circuit unit 12.

[0063] Furthermore, in the control device 14 of the power conversion device 10 according to this embodiment, the signal generating unit 40 generates a simulated control command signal when the main circuit unit 12 stops power conversion operation, and the detection circuit 42 detects abnormalities in the control transmission paths 16a, 16b for transmitting the control command signal based on the input simulated control command signal and control response signal.

[0064] As a result, the power conversion device 10 according to this embodiment can detect an abnormality in the control transmission paths 16a and 16b before causing the main circuit unit 12 to perform power conversion. Therefore, for example, it is possible to prevent an abnormality in the control transmission paths 16a and 16b from making it impossible to appropriately control the power conversion operation of the main circuit unit 12, thereby preventing breakdowns in components such as the switching element 50 used in the main circuit unit 12.

[0065] In the power conversion device 10 according to this embodiment, there is no need for an operator to inspect the transmission paths every time the power conversion operation of the main circuit unit 12 is stopped. Therefore, in the power conversion device 10 according to this embodiment, abnormalities in the control transmission paths 16a, 16b and the protection transmission paths 18a, 18b can be easily detected before the main circuit unit 12 is caused to perform power conversion operation.

[0066] In addition, when the power conversion device 10 has multiple transmission paths such as the control transmission paths 16a and 16b and the protection transmission paths 18a and 18b, it is not necessary to detect abnormalities in each of the multiple transmission paths. For example, the power conversion device 10 may detect abnormalities only in the control transmission paths 16a and 16b, or only in the protection transmission paths 18a and 18b. When the power conversion device 10 has multiple transmission paths, it may be configured to detect abnormalities in at least one of the transmission paths.

[0067] Furthermore, the transmission paths for detecting abnormalities are not limited to the control transmission paths 16a, 16b and the protection transmission paths 18a, 18b, but may be any transmission path between the main circuit unit 12 and the control device 14. The control device 14 may be configured in any manner that includes at least a signal generating unit that generates a simulated command signal when the main circuit unit 12 stops power conversion operation and transmits the generated simulated command signal to the main circuit unit 12 via the transmission path, and a detection circuit that detects an abnormality in the transmission path when a response signal corresponding to the simulated command signal is not transmitted from the main circuit unit 12 even when the simulated command signal is transmitted to the main circuit unit 12.

[0068] FIG. 4 is a block diagram schematically illustrating a modified example of the power conversion device according to the embodiment. 4, the power conversion device 10a further includes a host control device 60. Note that components that are substantially the same in function and configuration as those described in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0069] The upper control device 60 is connected to the control device 14 via separate transmission paths 62a and 62b. In this example, the power conversion device 10a includes a plurality of main circuit units 12 and a plurality of control devices 14 provided corresponding to the plurality of main circuit units 12, respectively. The upper control device 60 is connected to each of the plurality of control devices 14 via separate transmission paths 62a and 62b, for example. The upper control device 60 transmits control signals related to the control of the main circuit units 12 to each control device 14 via the separate transmission paths 62a and 62b.

[0070] Each control device 14 generates a command signal, such as a control command signal or a protection command signal, based on a control signal transmitted from the upper control device 60. The control signal is, for example, a command value representing the magnitude of power output from each main circuit unit 12. Each control device 14 generates, for example, a pulse signal for switching a switching element between an ON state and an OFF state as a control command signal based on the control signal transmitted from the upper control device 60. However, the control signal is not limited to the above and may be any signal related to the control of the main circuit unit 12. In other words, the control signal may be any signal required to generate a command signal. The upper control device 60 communicates with, for example, a higher-level controller and transmits control signals to each control device 14 based on commands from the higher-level controller. The number of transmission paths 62a, 62b provided between the upper control device 60 and the control device 14 is not limited to one each, and may be multiple. For example, the upper control device 60 may transmit multiple control signals to the control device 14 via multiple transmission paths.

[0071] When the main circuit unit 12 stops power conversion operation, the upper control device 60 transmits a simulated control signal corresponding to the control signal to each control device 14 via another transmission path 62a, 62b, and detects an abnormality in the other transmission path 62a, 62b if a response signal corresponding to the simulated control signal is not transmitted from the control device 14 even when the simulated control signal is transmitted to each control device 14. When the upper control device 60 detects an abnormality in the other transmission path 62a, 62b, for example, it outputs a signal indicating the detection of the abnormality.

[0072] Each control device 14 and the upper control device 60 may also be called, for example, a control panel. In a power conversion device, the operation of the main circuit unit 12 may be controlled by a plurality of control devices arranged hierarchically in this manner. In such a case, as described above, the upper control device 60 is caused to detect abnormalities in the transmission paths 62a, 62b between the control device 14. This makes it possible to easily detect abnormalities in the transmission paths 62a, 62b before causing the main circuit unit 12 to perform power conversion operations, without requiring the efforts of workers or the like. This makes it possible to further improve the reliability of the power conversion device 10a, for example.

[0073] In this way, the transmission path for detecting an abnormality is not limited to the transmission path between the main circuit unit 12 and the control device 14, but may also be a transmission path between the control device 14 and another control device. For example, two control devices 14 may be provided for one main circuit unit 12, one of the two control devices 14 being an operating system and the other being a standby system, and when an abnormality occurs in the control device 14 of the operating system, the control device 14 is switched to the standby system control device 14. In this case, an abnormality may be detected in the transmission path between the control device 14 of the operating system and the control device 14 of the standby system. In this case, the abnormality may be detected in both the control devices 14 of the operating system and the standby system, or may be detected only in the control device 14 of the operating system. This makes it possible to prevent, for example, when an abnormality occurs in the control device 14 of the operating system, from being unable to appropriately switch operation to the standby system control device 14 due to an abnormality in the transmission path.

[0074] 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 a transmission path, transmitting a command signal to the main circuit unit via the transmission path, and receiving a response signal transmitted from the main circuit unit in response to the command signal via the transmission path, thereby controlling an operation of the main circuit unit; Equipped with The control device a signal generating unit that generates a simulated command signal corresponding to the command signal when the main circuit unit stops power conversion operation and transmits the simulated command signal to the main circuit unit via the transmission path; a detection circuit that detects an abnormality in the transmission path when the response signal corresponding to the simulated command signal is not transmitted from the main circuit unit even when the simulated command signal is transmitted to the main circuit unit; A power conversion device having:

[0075] (Appendix 2) the control device transmits a protection command signal to the main circuit section via the transmission path as the command signal for causing the main circuit section to perform a protection operation; the signal generating unit generates a simulated protection command signal corresponding to the protection command signal as the simulated command signal, and transmits the simulated protection command signal to the main circuit unit via the transmission path; The power conversion device according to claim 1, wherein the detection circuit detects an abnormality in the transmission path for transmitting the protection command signal when the response signal corresponding to the simulated protection command signal is not transmitted from the main circuit unit even when the simulated protection command signal is transmitted to the main circuit unit.

[0076] (Appendix 3) the control device transmits a control command signal for controlling the power conversion operation of the main circuit section as the command signal to the main circuit section via the transmission path; the signal generating unit generates a simulated control command signal corresponding to the control command signal as the simulated command signal, and transmits the simulated control command signal to the main circuit unit via the transmission path; 3. The power conversion device according to claim 1, wherein the detection circuit detects an abnormality in the transmission path for transmitting the control command signal when the response signal corresponding to the simulated control command signal is not transmitted from the main circuit unit even when the simulated control command signal is transmitted to the main circuit unit.

[0077] (Appendix 4) 4. The power conversion device according to claim 1, wherein the signal generating unit generates the simulated command signal when starting up the main circuit unit and before starting up the main circuit unit.

[0078] (Appendix 5) 4. The power conversion device according to claim 1, wherein the signal generation unit constantly generates the simulated command signal when the power conversion operation of the main circuit unit is stopped.

[0079] (Appendix 6) 4. The power conversion device according to claim 1, wherein the signal generation unit periodically generates the simulated command signal when the power conversion operation of the main circuit unit is stopped.

[0080] (Appendix 7) The power conversion device according to any one of appendices 1 to 3, wherein the signal generating unit receives an input of an external signal and generates the simulated command signal based on the input of the external signal when the power conversion operation of the main circuit unit is stopped.

[0081] (Appendix 8) a host control device connected to the control device via another transmission path and transmitting a control signal related to control of the main circuit unit to the control device via the other transmission path; The power conversion device according to any one of appendices 1 to 7, wherein the upper control device transmits a simulated control signal corresponding to the control signal to the control device via the other transmission path when the main circuit unit stops power conversion operation, and detects an abnormality in the other transmission path if a response signal corresponding to the simulated control signal is not transmitted from the control device even when the simulated control signal is transmitted to the control device.

[0082] 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]

[0083] REFERENCE SIGNS LIST 10, 10a...power conversion device, 12...main circuit section, 14...control device, 16a, 16b...control transmission path, 18a, 18b...protection transmission path, 30...actual signal generation section, 32...simulation signal generation section, 34...OR circuit, 36...detection circuit, 40...signal generation section, 42...detection circuit, 50...switching element, 52...drive circuit, 60...host control device, 62a, 62b...transmission path

Claims

1. a main circuit section that converts power; a control device connected to the main circuit unit via a transmission path, transmitting a command signal to the main circuit unit via the transmission path, and receiving a response signal transmitted from the main circuit unit in response to the command signal via the transmission path, thereby controlling an operation of the main circuit unit; Equipped with The control device a signal generating unit that generates a simulated command signal corresponding to the command signal when the main circuit unit stops power conversion operation and transmits the simulated command signal to the main circuit unit via the transmission path; a detection circuit that detects an abnormality in the transmission path when the response signal corresponding to the simulated command signal is not transmitted from the main circuit unit even when the simulated command signal is transmitted to the main circuit unit; A power conversion device having:

2. the control device transmits a protection command signal to the main circuit section via the transmission path as the command signal for causing the main circuit section to perform a protection operation; the signal generating unit generates a simulated protection command signal corresponding to the protection command signal as the simulated command signal, and transmits the simulated protection command signal to the main circuit unit via the transmission path; 2. The power conversion device according to claim 1, wherein the detection circuit detects an abnormality in the transmission path for transmitting the protection command signal when the response signal corresponding to the simulated protection command signal is not transmitted from the main circuit unit even when the simulated protection command signal is transmitted to the main circuit unit.

3. the control device transmits a control command signal for controlling the power conversion operation of the main circuit section as the command signal to the main circuit section via the transmission path; the signal generating unit generates a simulated control command signal corresponding to the control command signal as the simulated command signal, and transmits the simulated control command signal to the main circuit unit via the transmission path; 2. The power conversion device according to claim 1, wherein the detection circuit detects an abnormality in the transmission path for transmitting the control command signal when the response signal corresponding to the simulated control command signal is not transmitted from the main circuit unit even when the simulated control command signal is transmitted to the main circuit unit.

4. The power conversion device according to claim 1 , wherein the signal generating unit generates the simulated command signal when starting up the main circuit unit and before starting up the main circuit unit.

5. The power conversion device according to claim 1 , wherein the signal generating section constantly generates the simulated command signal when the power conversion operation of the main circuit section is stopped.

6. The power conversion device according to claim 1 , wherein the signal generating unit periodically generates the simulated command signal when the power conversion operation of the main circuit unit is stopped.

7. The power conversion device according to claim 1 , wherein the signal generating unit receives an input of an external signal, and generates the simulated command signal based on the input of the external signal when the power conversion operation of the main circuit unit is stopped.

8. a host control device connected to the control device via another transmission path and transmitting a control signal related to control of the main circuit unit to the control device via the other transmission path; The power conversion device according to claim 1, wherein the upper control device transmits a simulated control signal corresponding to the control signal to the control device via the other transmission path when the main circuit unit stops power conversion operation, and detects an abnormality in the other transmission path if, even when the simulated control signal is transmitted to the control device, a response signal corresponding to the simulated control signal is not transmitted from the control device.

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