Power conversion system and system switching control method

Abstract

This invention provides a power conversion system and a system switching control method that can improve the responsiveness of system switching control for power conversion devices with standby redundancy configurations. [Solution] In a standby redundant power conversion system, the first circuit breaker disconnects the connection between the output of the first power converter and the load. The second circuit breaker disconnects the connection between the output of the second power converter and the load. The first control device controls the first main circuit, the first circuit breaker and the second circuit breaker based on a first diagnostic result obtained by combining the result of a first self-diagnosis and the result of a second self-diagnosis obtained from the second control device, so that both the first and second circuit breakers do not become conductive. The second control device controls the second main circuit, the first circuit breaker and the second circuit breaker based on a second diagnostic result obtained by combining the result of a second self-diagnosis and the result of a first self-diagnosis obtained from the first control device, thereby controlling the first and second control devices.

Description

Technical Field

[0001] The present invention relates to a power conversion system and a system switching control method.

Background Art

[0002] There is a standby redundant power conversion system including two inverters. It has been desired to improve the responsiveness of system switching in a standby redundant configuration.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a power conversion system and a system switching control method capable of improving the responsiveness of system switching control for a power conversion device of a standby redundant configuration.

Means for Solving the Problems

[0005] The power conversion system of this embodiment is a power conversion system configured as a standby redundant type. The power conversion system comprises a first power converter, a second power converter, a first circuit breaker, and a second circuit breaker. The first power converter includes a set of a first main circuit and a first control device. The second power converter includes a set of a second main circuit and a second control device. The first control device performs a first self-diagnosis based on the state of the first main circuit. The second control device performs a second self-diagnosis based on the state of the second main circuit. The first control device controls the first main circuit, the first circuit breaker and the second circuit breaker based on a first diagnostic result obtained by combining the result of the first self-diagnosis and the result of the second self-diagnosis obtained from the second control device, so that both the first circuit breaker and the second circuit breaker do not enter a conductive state. The second control device controls the second main circuit, the first circuit breaker and the second circuit breaker based on a second diagnostic result obtained by combining the result of the second self-diagnosis and the result of the first self-diagnosis obtained from the first control device, thereby controlling the first control device and the second control device. [Brief explanation of the drawing]

[0006] [Figure 1] A schematic diagram of the power conversion system according to the embodiment. [Figure 2] A flowchart of the process related to system switching control in the embodiment. [Figure 3] A diagram illustrating the system switching control of the power conversion system 1 of the embodiment. [Modes for carrying out the invention]

[0007] The power conversion system and system switching control method of the embodiment will be described below with reference to the drawings. In the following explanation, components with the same or similar functions will be denoted by the same reference numeral. Furthermore, redundant explanations of these components may be omitted. Note that the term "connected" may be used to simply refer to an electrical connection.

[0008] (First embodiment) Referring to Figure 1, the power conversion system 1 of the embodiment will be described. Figure 1 is a schematic diagram of the power conversion system 1 of the embodiment. The connections between the devices are shown in a single-line diagram.

[0009] The power conversion system 1 drives the motor 30. The motor 30 is an example of an AC motor. The motor 30 may be, for example, a three-phase AC motor.

[0010] The power conversion system 1 includes, for example, a single-system inverter 10, a second-system inverter 20, and circuit breakers CB1 (first circuit breaker) and CB2 (second circuit breaker). The power conversion system 1 is configured as an active-standby type with a redundant configuration of the single-system inverter 10 and the second-system inverter 20.

[0011] The AC output terminal Tb10 of the 1-system inverter 10 is connected to the motor 30 via the first AC bus BUS1. The first AC bus BUS1 is equipped with a circuit breaker CB1. The circuit breaker CB1 controls the connection between the AC output terminal Tb10 of the 1-system inverter 10 and the motor 30.

[0012] The AC output terminal Tb20 of the 2-system inverter 20 is connected to the motor 30 via the second AC bus BUS2. A circuit breaker CB2 is provided on the second AC bus BUS2. The circuit breaker CB2 controls the connection between the AC output terminal Tb20 of the 2-system inverter 20 and the motor 30.

[0013] Let me explain the 1-series inverter 10 in more detail. The single-system inverter 10 includes, for example, a single-system main circuit 11 and a single-system control circuit 12. The combination of the first main circuit 11 and the first control circuit 12 is an example of a combination of the first main circuit and the first control device. The main circuit 11 of system 1 includes multiple semiconductor switches configured in a full-bridge type. The single-system control circuit 12 sends control signals to each semiconductor switch in the single-system main circuit 11, and by switching each of them, converts DC power into AC power, which is used to drive the motor 30. The single-system control circuit 12 detects the state of the single-system main circuit 11. For example, when a fault occurs in the single-system main circuit 11, the single-system control circuit 12 receives a fault signal and identifies that a fault has occurred.

[0014] Let me explain the 2-series inverter 20 in more detail. The dual inverter 20 includes, for example, a dual main circuit 21 and a dual control circuit 22. The combination of the two-system main circuit 21 and the two-system control circuit 22 is an example of a combination of a second main circuit and a second control device. The two-system main circuit 21 includes multiple semiconductor switches configured in a full-bridge configuration. The two-system control circuit 22 sends control signals to each semiconductor switch in the two-system main circuit 21, and by switching each of them, converts DC power into AC power, which is used to drive the motor 30. The two-system control circuit 22 detects the state of the two-system main circuit 21. For example, when a fault occurs in the two-system main circuit 21, the two-system control circuit 22 receives a fault signal and identifies that a fault has occurred.

[0015] The control circuit 12 and the control circuit 22 of system 1 can share their diagnostic results with each other by notifying the other system of their own diagnostic results. This notification may be made using communication messages or contact signals. A suitable method may be selected from among the well-known methods.

[0016] Furthermore, the control circuit 12 for system 1 and the control circuit 22 for system 2 switch between the active system and the standby system using each other's diagnostic results. For example, the System 1 control circuit 12 obtains a first diagnostic result by combining the result of a first self-diagnosis related to the System 1 main circuit 11 and the result of a second self-diagnosis obtained from the System 2 control circuit 22. Based on the first diagnostic result, the System 1 control circuit 12 controls the System 1 main circuit 11 and circuit breakers CB1 and CB2. The 2-system control circuit 22 obtains a second diagnosis result by combining the result of the second self-diagnosis related to the 2-system main circuit 21 and the result of the first self-diagnosis acquired from the 1-system control circuit 12. The 2-system control circuit 22 controls the 2-system main circuit 21, the circuit breaker CB1, and the circuit breaker CB2 based on the second diagnosis result.

[0017] A more specific example of system switching control will be described with reference to FIG. 2 and FIG. 3. FIG. 2 is a flowchart of processing related to system switching control according to the embodiment.

[0018] The 1-system control circuit 12 and the 2-system control circuit 22 perform processing of the same procedure. Here, the processing of the 1-system control circuit 12 will be described as an example, but the same processing can be applied to the 2-system control circuit 22.

[0019] The 1-system control circuit 12 detects a failure in the 1-system main circuit 11 (S11). The 1-system control circuit 12 refers to the setting information of the operation mode to determine whether or not the own system (the 1-system in this case) is the active system (operating system) (S12). For example, the setting information of the operation mode is binary information based on data in the storage unit or a state held in the state holding circuit. The 1-system control circuit 12 reads the data in the storage unit or the state held in the state holding circuit to identify the current state.

[0020] If the own system is not the active system (operating system), the 1-system control circuit 12 holds the state and continues the current operation (S13).

[0021] When the own system is the active system (operating system), the 1-system control circuit 12 determines whether or not the other system is in a normal state (S14).

[0022] The System 1 control circuit 12 performs a system switchover (S16) if its own system is the active system (operating system) and the other system is in a normal state. For example, the System 1 control circuit 12 stops the operation of the System 1 main circuit 11, opens the circuit breaker CB1, and updates the operating mode setting information referenced by the System 1 control circuit 12 to standby mode. Subsequently, the System 1 control circuit 12 notifies the System 2 control circuit 22 that a fault has occurred in its own system and closes the circuit breaker CB2. Upon receiving the above notification, the System 2 control circuit 22 updates the operating mode setting information it references to the operating mode and starts operation with System 2 as the active system (operating system).

[0023] In contrast, if the system 1 control circuit 12 is the active system (operating system) and the other system is not in a normal state, it stops the operation of its own system without performing a system switchover (S15). In this case, system 2, which the system 1 control circuit 12 considers to be the other system, is already stopped, and when system 1 stops, the power conversion of the power conversion system 1 is stopped.

[0024] The above process enables the system switching control of power conversion system 1. Thus, the system switching control of the power conversion system 1 is achieved by controlling the system 1 control circuit 12 and the system 2 control circuit 22 respectively, without receiving a system switching command from a higher-level device.

[0025] Referring to Figure 3, the system switching control of the power conversion system 1 of the embodiment will be described. Figure 3 is a diagram illustrating the system switching control of the power conversion system 1 of the embodiment. The system switching control of power conversion system 1 switches between five states: ST0, ST1, ST2, ST10, and ST20.

[0026] [Power conversion system 1 is stopped] When the power conversion system 1 is in state ST0, the power conversion system 1 is in a paused (stopped) state.

[0027] [Power conversion system 1 standby redundant operation state] State ST1 is the state in which system 1 is operated as the active system and system 2 is set to standby. When power conversion system 1 is in state ST1, power conversion system 1 operates system 1 as the active system and controls system 2 to standby. State ST2 is the state in which system 2 is operated as the active system and system 1 is set to standby. When power conversion system 1 is in state ST2, power conversion system 1 operates system 2 as the active system and controls system 1 to standby.

[0028] [Operating conditions when a single fault occurs in power conversion system 1] A single fault may occur during the operation of power conversion system 1. The following conditions are available to address this. State ST10 indicates a failure in system 2 of power conversion system 1. When power conversion system 1 is in state ST10, power conversion system 1 operates system 1 as the primary system and shuts down system 2. State ST20 indicates a failure in one system of power conversion system 1. When power conversion system 1 is in state ST20, it operates system 2 as the primary system and shuts down system 1.

[0029] The transitions from one of these states to another can be defined as follows:

[0030] As described above, when the status information is in state ST0, the operating modes of the System 1 control circuit 12 and the System 2 control circuit 22 are both stopped.

[0031] When the status information is in state ST0, and both the System 1 control circuit 12 and the System 2 control circuit 22 receive a system start command from a higher-level device, both the System 1 control circuit 12 and the System 2 control circuit 22 update their respective status information to state ST1. Accordingly, the System 1 control circuit 12 updates its operating mode to the active system, and the System 2 control circuit 22 updates its operating mode to the standby system. The System 1 control circuit 12 starts operation in the active system operating mode, and the System 2 control circuit 22 starts operation in the standby system operating mode.

[0032] When the status information is in state ST1, the system 1 control circuit 12 detects a fault in its own system and updates the status information it holds to state ST20. Consequently, the system 1 control circuit 12 notifies the system 2 control circuit 22 that a fault has occurred in its own system. In response, the system 2 control circuit 22 updates the status information it holds from state ST1 to state ST20. As a result, the system 1 control circuit 12 puts its own system into a stop operation mode, and the system 2 control circuit 22 starts operating its own system in the active system operation mode.

[0033] When the status information is in state ST1, the system 2 control circuit 22 detects a fault in its own system and updates the status information it holds to state ST10. The system 2 control circuit 22 notifies the system 1 control circuit 12 that a fault has occurred in its own system. In response, the system 1 control circuit 12 updates the status information it holds from state ST1 to state ST10. As a result, the system 1 control circuit 12 maintains the operating mode of the active system, and the system 2 control circuit 22 enters the stopped operating mode.

[0034] Thus, when the status information is in state ST1, it is updated to either state ST10 or state ST20 depending on whether a fault is detected. Even in state ST10 or state ST20, where a single fault has occurred, the function of operating the power conversion system 1 using the active system is maintained.

[0035] [If two failures occur in power conversion system 1] Next, we will explain the case where two failures occur. If the status information is ST10, it means that a single fault has already occurred in system 2 and it has stopped, and system 1 is operating as the primary system. In this situation, the redundancy function cannot be used. In this state, if a failure occurs in the active system 1, the power conversion system 1 cannot be used continuously and will be shut down to prevent secondary damage. In this case, when the System 1 control circuit 12 detects a fault in its own system, it updates the state information it holds to state ST0. The System 1 control circuit 12 notifies the System 2 control circuit 22 that a fault has occurred in its own system. In response, the System 2 control circuit 22 updates the state information it holds from state ST10 to state ST0. As a result, the System 1 control circuit 12 puts its own system into a stop operation mode. The System 2 control circuit 22 is already in a stop operation mode, so both systems are stopped.

[0036] If the status information is ST20, it means that a single fault has already occurred in system 1 and it has stopped, while system 2 is operating as the primary system. In this situation, the redundancy function cannot be used. In this state, if a failure occurs in the two active systems, the power conversion system 1 cannot be used continuously and will be shut down to prevent secondary damage. In this case, when the System 2 control circuit 22 detects a fault in its own system, it updates the state information it holds to state ST0. The System 2 control circuit 22 notifies the System 1 control circuit 12 that a fault has occurred in its own system. In response, the System 1 control circuit 12 updates the state information it holds from state ST20 to state ST0. As a result, the System 2 control circuit 22 puts its own system into a stop operation mode. Since the System 1 control circuit 12 is already in a stop operation mode, both systems are stopped.

[0037] [Recovery from an operating condition where a single fault occurred in power conversion system 1] A single problem may be resolved. For example, if the system's status information is in state ST10, and the system's fault condition has been resolved, the system's control circuit 22 updates its status information to state ST1. The system's control circuit 22 then notifies the system's control circuit 12 that its fault condition has been resolved. In response, the system's control circuit 12 updates its status information to state ST1. Alternatively, if the system's status information is status ST20 and the fault condition of system 1 is detected to have been resolved, the system 1 control circuit 12 updates the status information it holds to status ST2. The system 1 control circuit 12 notifies the system 2 control circuit 22 that the fault condition of its own system has been resolved. In response, the system 2 control circuit 22 updates the status information it holds to status ST2. By defining this state ST2, it becomes possible to control the system so that a system switchover does not occur even when the fault condition of system 1 is resolved and the system returns to an operational state.

[0038] Furthermore, if a fault condition in system 2 is detected while the status information is in state ST2, the system 2 control circuit 22 updates the status information it holds to state ST10. This triggers a system switchover. However, by defining this state ST2, it becomes possible to control the system so that unnecessary system switching does not occur if the fault condition of system 1 is resolved while waiting for a state transition.

[0039] The power conversion system 1 in the above embodiment controls the system so as not to short-circuit the outputs of both the first inverter 10 and the second inverter 20, that is, so as not to cause both circuit breakers CB1 and CB2 to become conductive. This improves the responsiveness of the system switching control of the inverters (power converters) in a standby redundant configuration.

[0040] For example, if the first control unit (system 1 control circuit 12) detects a fault in its own system's main circuit (first main circuit), and if its own system is not the active system, it will continue operating with another system as the active system. Alternatively, if the system is the active system, the circuit breaker CB1 (first circuit breaker) is tripped, and the normality of the other system is determined based on the diagnostic result (second diagnostic result) from the two-system control circuit 22. If the other system is normal based on this determination, information is sent to the two-system control circuit 22 prompting it to switch the other system to the active system. If the other system is not normal, it is advisable to at least shut down the system itself.

[0041] Furthermore, after detecting a fault in its own system's main circuit (second main circuit), the second control unit (system 2 control circuit 22) will continue operating with the other system as the active system if its own system is not the active system. Alternatively, if the system is the active system, the circuit breaker CB2 (second circuit breaker) is tripped, and the normality of the other system is determined based on the diagnostic result (first diagnostic result) from the system 1 control circuit 12. If the other system is normal based on this determination, information is sent to the system 1 control circuit 12 prompting it to switch the other system to the active system. If the other system is not normal, it is advisable to at least shut down the system itself.

[0042] (Comparison with comparative example) In a comparative example, there is a power conversion system with an active / standby redundant configuration in which a higher-level device (main unit) is responsible for functions such as system switching control to assign active / standby systems and monitoring operating status. In such a comparative example, commands are generated based on the operating status information collected by the higher-level device (main unit). Each part of the redundant configuration controls the state of its own system based on these commands, resulting in a delay between the occurrence of a condition requiring system switching control and the actual completion of the system switching. In this embodiment, the higher-level device (main circuit breaker) of the power conversion system 1 does not have a system switching control function. Even if the higher-level device (main circuit breaker) does not have a system switching control function, this embodiment can shorten the time required for system switching (response time) compared to the comparative example.

[0043] According to at least one embodiment described above, the power conversion system is a power conversion system configured in a standby redundant manner. The power conversion system comprises a first power converter, a second power converter, a first circuit breaker, and a second circuit breaker. The first power converter includes a set of a first main circuit and a first control device. The second power converter includes a set of a second main circuit and a second control device. The first circuit breaker disconnects the connection between the output of the first power converter and the load. The second circuit breaker disconnects the connection between the output of the second power converter and the load. The first control device performs a first self-diagnosis based on the state of the first main circuit. The second control device performs a second self-diagnosis based on the state of the second main circuit. The first control device controls the first main circuit, the first circuit breaker and the second circuit breaker based on a first diagnostic result obtained by combining the result of the first self-diagnosis and the result of the second self-diagnosis obtained from the second control device, so that both the first circuit breaker and the second circuit breaker do not enter a conductive state. The second control device controls the second main circuit, the first circuit breaker and the second circuit breaker based on a second diagnostic result obtained by combining the result of the second self-diagnosis and the result of the first self-diagnosis obtained from the first control device, thereby controlling the first control device and the second control device. This improves the responsiveness of system switching control for power converters in a standby redundant configuration.

[0044] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented 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 variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. [Explanation of Symbols]

[0045] 1. Power Conversion System 10-1 type inverter 11 1 system main circuit 12. Control circuit for system 1 20 2-series inverter 21 2 system main circuit 22 2-system control circuit CB1, CB2 circuit breakers

Claims

1. A power conversion system configured as a standby redundant type, A first power converter including a set of a first main circuit and a first control device, A second power converter including a second main circuit and a second control device, A first circuit breaker that disconnects the connection between the output of the first power converter and the load, A second circuit breaker that disconnects the connection between the output of the second power converter and the load, Equipped with, The first control device performs a first self-diagnosis based on the state of the first main circuit. The second control device performs a second self-diagnosis based on the state of the second main circuit. In order that both the first circuit breaker and the second circuit breaker do not become conductive, The first control device controls the first main circuit, the first circuit breaker, and the second circuit breaker based on a first diagnostic result obtained by combining the result of the first self-diagnosis and the result of the second self-diagnosis obtained from the second control device. The second control device controls the second main circuit, the first circuit breaker, and the second circuit breaker based on a second diagnostic result obtained by combining the result of the second self-diagnosis and the result of the first self-diagnosis acquired from the first control device. Power conversion system.

2. The first control device is After detecting a fault in the first main circuit of the system, If the aforementioned system is not the active system, the operating state will continue with another system as the active system. If the aforementioned system is the currently operating system, the first circuit breaker is tripped, and the normality of the other system is determined based on the second diagnostic result. If the other system is functioning normally, the second control device is sent information prompting it to switch the other system to the active system. If the other system is not functioning normally, at least the system itself will be shut down. The power conversion system according to claim 1.

3. The second control device is After detecting a fault in the second main circuit of the system, If the aforementioned system is not the active system, the operating state will continue with another system as the active system. If the aforementioned system is the currently operating system, the second circuit breaker is tripped, and the normality of the other system is determined based on the first diagnostic result. If the other system is functioning normally, the first control device is sent information prompting it to switch the other system to the active system. If the other system is not functioning normally, at least the system itself will be shut down. The power conversion system according to claim 2.

4. A method for controlling the system switching of a power conversion system configured in a standby redundant type, The aforementioned power conversion system, A first power converter including a set of a first main circuit and a first control device, A second power converter including a second main circuit and a second control device, A first circuit breaker that disconnects the connection between the output of the first power converter and the load, A second circuit breaker that disconnects the connection between the output of the second power converter and the load, Equipped with, The first control device performs a first self-diagnosis based on the state of the first main circuit. The second control device performs a second self-diagnosis based on the state of the second main circuit. In order that both the first circuit breaker and the second circuit breaker do not become conductive, The first control device controls the first main circuit, the first circuit breaker, and the second circuit breaker based on a first diagnostic result obtained by combining the result of the first self-diagnosis and the result of the second self-diagnosis obtained from the second control device. The second control device controls the second main circuit, the first circuit breaker, and the second circuit breaker based on a second diagnostic result obtained by combining the result of the second self-diagnosis and the result of the first self-diagnosis obtained from the first control device. A system switching control method that includes this.

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