WO2024047710A1

WO2024047710A1 - Electric power conversion control device, electric power conversion device, and protection method

Info

Publication number: WO2024047710A1
Application number: PCT/JP2022/032446
Authority: WO
Inventors: 久貴手塚; 裕介石田
Original assignee: 東芝三菱電機産業システム株式会社
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2024-03-07

Abstract

This electric power conversion control device comprises: an optical fiber; an optical detection part; and a protection control part. The optical fiber is formed to guide light taken in through the side surface of an extending light guide part in the extension direction and to output the light from an end of the light guide part. The optical detection part detects the light guided to the end of the light guide part. When the optical detection part has detected light resulting from an accident accompanied by arc flash, the protection control part halts electric power conversion carried out by an electric power converter relating to the optical fiber.

Description

Power conversion control device, power conversion device and protection method

Embodiments of the present invention relate to a power conversion control device, a power conversion device, and a protection method.

Arc flash may occur due to accidents such as short circuits and insulation breakdown in the circuits that make up the power converter. Even if a protection circuit (protection device) is provided to detect a fault current caused by an accident involving an arc flash and cut off the fault current, it may not be possible to prevent secondary failures due to this fault. There has been a desire for a power conversion control device that can prevent secondary failures caused by accidents that cause arc flash.

Japanese Patent Publication No. 2000-065887

The problem to be solved by the present invention is to provide a power conversion control device, a power conversion device, and a protection method that can easily prevent the occurrence of secondary failures caused by accidents that cause arc flash. It is to provide.

The power conversion control device of the embodiment includes an optical fiber, a light detection section, and a protection control section. The optical fiber is formed so as to guide the light taken in by the side surface of the extending light guide part in the extending direction, and output it from the end of the light guide part. The light detection section detects the light guided to the end of the light guide section. The protection control unit interrupts power conversion by a power converter related to the optical fiber when light caused by an accident involving an arc flash is detected by the light detection unit.

FIG. 1 is a schematic configuration diagram of a power conversion device according to an embodiment. FIG. 1 is a configuration diagram of a power conversion control device according to an embodiment. FIG. 1 is a cross-sectional view of an optical fiber according to an embodiment. FIG. 3 is a cross-sectional view of an optical fiber in a section arranged in a straight line. A secondary cross-sectional view of optical fibers arranged in an arc. A secondary cross-sectional view of optical fibers arranged in an arc. FIG. 1 is a cross-sectional view showing the arrangement of optical fibers according to an embodiment. FIG. 3 is a plan view showing the arrangement of optical fibers according to the embodiment. FIG. 3 is a diagram for explaining protection control when arc flash occurs according to the embodiment. FIG. 3 is a cross-sectional view showing the arrangement of optical fibers in a first modification of the embodiment. FIG. 7 is a plan view showing the arrangement of optical fibers in a first modified example of the embodiment. FIG. 2 is a schematic configuration diagram of a power conversion control device according to a first modification of the embodiment. FIG. 7 is a cross-sectional view showing the arrangement of optical fibers in a second modification of the embodiment. FIG. 7 is a plan view showing the arrangement of optical fibers in a second modification of the embodiment. FIG. 7 is a schematic configuration diagram of a power conversion control device according to a second modification of the embodiment.

Hereinafter, a power conversion control device, a power conversion device, and a protection method according to an embodiment will be described. Note that the term "connection" used in this specification is not limited to a physical connection, but also includes an electrical connection. In the specification, "based on XX" means "based on at least XX," and includes cases where it is based on another element in addition to XX. Furthermore, "based on XX" is not limited to the case where XX is used directly, but also includes the case where it is based on calculations and processing performed on XX. "XX" is an arbitrary element (for example, arbitrary information). In addition, components having the same or similar functions are given the same reference numerals.

First, a power conversion device 1 according to an embodiment will be described.
FIG. 1 is a schematic configuration diagram of a power conversion device 1 according to an embodiment.
Power conversion device 1 shown in FIG. 1 includes a rectifier 110, a reactance 120, a first capacitor 130, an inverter 150, and a control device 20. The rectifier 110 and inverter 150 described above form a main circuit 190 of the power converter 1.

The rectifier 110 rectifies AC power. The input terminal of the rectifier 110 is connected to an AC power system PS via a transformer T, and the output terminal of the rectifier 110 is connected to an inverter 150 via a DC link 180. For example, the rectifier 110 is formed as a three-level type. In this case, the rectifier 110 includes a positive bridge circuit 110P and a negative bridge circuit 110N. The DC link 180 includes a positive bus line PBL, a neutral line N, and a negative bus line NBL. The positive bridge circuit 110P and the negative bridge circuit 110N perform full-wave rectification on the power supplied from the AC power system PS via the transformer T, and supply the rectified power to the positive bus PBL and the negative bus NBL. Note that the rectifier 110 is an example of a converter (diode converter) that does not have a regeneration circuit. The power supply line connecting the rectifier 110 and the transformer T may be provided with a fuse and a transformer.

The first capacitor 130 (not shown) is a capacitor for smoothing the voltage of the DC link 180. For example, the first capacitor 130 includes a positive first capacitor 130P and a negative first capacitor 130N. The first capacitor 130P on the positive side is connected to the positive bus line PBL and the neutral line N of the DC link 180. The negative first capacitor 130N is connected to the negative bus NBL and the neutral line N of the DC link 180. The set of rectifier 110 and first capacitor 130 described above is an example of a power source that supplies power to inverter 150, which will be described later. Note that the positive-side first capacitor 130P is provided with a parallel circuit PCP for discharging, and the negative-side regeneration amount adjustment section 210N is provided with a parallel circuit PCN for discharging.

The inverter 150 is also formed of a three-level type, for example. The inverter 150 converts the power supplied from the rectifier 110 via the DC link 180 under the control of the control device 20 to generate AC power. The electric motor 2 is connected to the output terminal of the inverter 150. Inverter 150 supplies the converted AC power to electric motor 2. The inverter 150 and the electric motor 2 are, for example, a three-phase AC type having U-phase, V-phase, and W-phase, but are not limited thereto, and may be a single-phase AC type, or a multi-phase AC type with other numbers of phases. It's okay. The electric motor 2 is, for example, an induction motor, but is not limited thereto. Note that the electric motor 2 is an example of a load.

For example, the inverter 150 includes a plurality of semiconductor switching elements for each of the U-phase, V-phase, and W-phase, and is formed in a full-bridge type. Each of the plurality of semiconductor switching elements described above is provided with a flywheel diode. In order to simplify the explanation below, detailed explanation of the freewheel diode will be omitted.

More specifically, the inverter 150 includes switches QU1 to QU4 as U-phase semiconductor switching elements, switches QV1 to QV4 as V-phase semiconductor switching elements, and switch QW1 as a W-phase semiconductor switching element. Equipped with QW4.
The semiconductor switching elements of each phase described above are, for example, IGBTs (Insulated Gate Bipolar Transistors), and are cascade-connected as shown in the figure. The type of semiconductor switching element is not limited and may be a power MOSFET or the like.

Protection circuits (150UP, 150UN, 150VP, 150VN, 150WP, 150WN) are provided between the semiconductor switching elements of each phase of the inverter 150 and the DC link 180 to protect the circuits from overcurrent. For example, these protection circuits each include a fuse that blows due to an overcurrent exceeding a predetermined current capacity, and are formed as "fuses with alarm contacts" whose contacts close in response to the blowing of the fuse. Each protection circuit can indicate to the outside world that it is in an alarm condition by closing an alarm contact when the fuse blows.

The inverter 150 is provided with an optical fiber 26 connected to the control device 20. The optical fiber 26 is configured separately from other optical fibers for controlling the inverter 150. Details regarding this will be described later.

With reference to FIG. 2, the control device 20 of the embodiment will be described.
FIG. 2 is a configuration diagram of the control device 20 of the embodiment. Control device 20 is an example of a power conversion control device. Control device 20 monitors and controls the state of inverter 150.

As shown in FIG. 2, the control device 20 is connected to the inverter 150. The semiconductor switching elements of each phase of the inverter 150 are controlled to be turned on or off by a gate pulse (GP3) supplied from the control device 20. In the configuration shown in FIG. 2, a gate pulse of an optical signal is supplied from the control device 20 via an optical fiber, and the OE unit of the inverter 150 converts the optical signal into a gate pulse GP3. The gate pulse GP3 is supplied to the gates of the semiconductor switching elements of each phase via a driver circuit.

The control device 20 may include a processor such as a CPU, for example. The control device 20 may be realized at least in part by a software function unit that functions when a processor such as a CPU executes a program, or may be entirely realized by a hardware function unit such as an LSI. There is no limit to the number of processors, and they may be divided as appropriate.

The control device 20 includes an inverter control section 21, a GB unit 22 (protection control section), an EO unit 23, an analysis unit 24, and an OE unit 25 (light detection section).
An optical fiber 26 used as a sensor is connected to the control device 20. The control device 20 may include an optical fiber 26 or may be provided separately.

The inverter control unit 21 controls the inverter 150 based on the detection results of the transformer HCT, protection circuit, etc. provided in the inverter 150. As a control method for the inverter 150, PWM (Pulse Width Modulation) control, vector control, etc. may be selected as appropriate. When a failure is detected from the detection result of a protection circuit provided in the inverter 150, the inverter control unit 21 may stop power conversion of the inverter 150 for protection.

For example, in a normal situation, the inverter control unit 21 generates a gate pulse GP1 for controlling on/off of the semiconductor switching elements of each phase of the inverter 150, and supplies it to the GB unit 22.

In order to bring the inverter 150 into a non-operating state, the inverter control unit 21 supplies the GB unit 22 with a gate block signal GB1 for instructing the inverter 150 to stop operating, thereby restricting the supply of gate pulses to the inverter 150. .

The GB unit 22 acquires the gate pulse GP1 and the gate block signals GB1, GB2, and GB3, and generates the gate pulse GP2. For example, the GB unit 22 determines the output of the gate pulse GP2 according to the signal state of the gate pulse GP1. At this time, the GB unit 22 may limit the supply of gate pulses to the inverter 150 based on the states of the gate block signals GB1, GB2, and GB3. The GB unit 22 limits the output of the gate pulse GP2 when any of the gate block signals GB1, GB2, and GB3 is in a significant state, regardless of the signal state of the gate pulse GP1 supplied from the inverter control unit 21. so that no pulses are output. For example, the GB unit 22 interrupts the power conversion by the inverter 150 by controlling the semiconductor switching elements related to the power conversion of the inverter 150 to an off state using the light detection result by the OE unit 25, which will be described later. It is configured as follows.

The EO unit 23 generates a light pulse according to the state of the gate pulse GP2 supplied from the GB unit 22. The EO unit 23 supplies the generated optical pulses to the inverter 150 via a light-shielding optical fiber.

The analysis unit 24 receives signals indicating the operating state of the inverter 150 and analyzes the operating state of the inverter 150 based on these signals. For example, the analysis unit 24 includes the output currents Iu, Iv, and Iw of the inverter 150, the output voltages Vu, Vv, and Vw of the inverter 150, and the state OC1 of the protection circuit.

The OE unit 25 (photodetection section) includes a photoelectric conversion section such as a photodiode and a phototransistor, and generates an electric signal according to the amount of detected light. The OE unit 25 uses the electrical signal to identify that there is light exceeding a predetermined amount of light. For example, the OE unit 25 detects the light guided to the end 261PA (FIGS. 3A, 3B) of the light guide section 261 (FIGS. 3A, 3B) of the optical fiber 26, and detects light exceeding a predetermined amount of light. When this occurs, the gate block signal GB3 is output.

The GB unit 22 (protection control section) limits the output of the gate pulse GP2 when the OE unit 25 detects light exceeding a predetermined amount of light and generates the gate block signal GB3 as described above. Then, by controlling the semiconductor switching elements of inverter 150 to be in an off state, power conversion by inverter 150 is interrupted.

The optical fiber 26 of the embodiment will be described with reference to FIGS. 3A to 3D.
FIG. 3A is a cross-sectional view of the optical fiber 26 of the embodiment. FIG. 3B is a cross-sectional view of the optical fiber 26 in a linearly arranged section. 3C and 3D are cross-sectional views of optical fibers 26 arranged in an arc. The arrows shown in FIGS. 3A to 3D indicate an example of the path of external light irradiated onto the optical fiber 26 from a point light source. The position of the point light source shown in FIG. 3C is outside the arc of the arcing optical fiber 26. The position of the point light source shown in FIG. 3D is inside the arc of the arcing optical fiber 26.

The optical fiber 26 includes, for example, a light guide section 261.
The light guide section 261 extends in the direction in which the optical fiber 26 extends.
The light guide portion 261 includes end portions 161PA, 161PB, and a side surface 261SS.

The light guide section 261 is made of resin (plastic), quartz glass, or both.

For example, the light guide section 261 is formed into a core and a cladding, like an optical fiber for communication. The core and cladding are arranged concentrically with respect to a common axis as shown in the cross-sectional view. In a first example of the light guide section 261, both the core and the cladding are made of resin. A second example of the light guide section 261 has a core made of quartz glass and a cladding made of resin. In a third example of the light guide section 261, both the core and the cladding are made of quartz glass.

The first example can be applied if the distance from the detection position by the optical fiber to the end on the OE unit 25 side is relatively short. In this case, the optical fiber may be formed into a multimode step-index type by making the core diameter of the light guiding portion 261 relatively large.

The optical fiber 26 is formed so as to guide the light taken in by the side surface 261SS of the light guide section 261 in the extending direction, and output it from the ends 161PA and 161PB of the light guide section 261, for example. In this embodiment, for example, it is assumed that light output from one of the end portions 161PA and 161PB is detected.

A shielding member is not provided on the side surface 261SS of the light guide section 261 of the optical fiber 26. At least in the portion where the optical fiber 26 is used as a sensor, no shielding member is provided on the side surface 261SS of the light guide section 261. The shielding member is, for example, a film having a light-shielding property or a cable covering having a light-shielding property. The optical fiber 26 takes in light from outside the light guide section 261 in a portion where a shielding member is not provided.

For example, as shown in FIGS. 3A and 3B, when light from a light source (point light source) is irradiated onto the optical fiber 26, it is taken into the light guide section 261 of the optical fiber 26. Depending on the angle of incidence on the side surface 261SS of the light guide section 261, the light taken into the light guide section 261 is guided in the extending direction of the light guide section 261 through the light guide section 261, or passes through the light guide section 261. The light is then radiated to the outside from the side surface 261SS of the optical fiber 26. The above-mentioned incident angle when the light can be guided in the extending direction of the light guide portion 261 may be determined geometrically according to Snell's law, for example, or may be determined by the characteristics of the surface treatment of the side surface 261SS. The side surface 261SS may be provided with a coating film or a coating film having a low reflection coefficient as its surface treatment, and may have a property of diffusing transmitted light. The larger the incident angle, the more the light can be guided in the extending direction of the light guide section 261. Therefore, it is easier to take in light when the point light source is located outside the arc as shown in FIG. 3C than when the point light source is located inside the arc as shown in FIG. 3D.

The optical fiber 26 formed in this way is an example of one that is formed so as to take in light from an arc flash generated in the vicinity thereof. By arranging the optical fiber 26 near a semiconductor switching element forming the inverter 150 (power converter) or a conductor section for passing current through the semiconductor switching element, the optical fiber 26 can be connected to the semiconductor switching element or the conductor section. Can capture light from arc flash.

An example of the arrangement of the optical fibers 26 in the inverter 150 and detection of arc flash will be described with reference to FIGS. 4A, 4B, and 5.
FIG. 4A is a cross-sectional view showing the arrangement of the optical fibers 26 of the embodiment. FIG. 4B is a plan view showing the arrangement of optical fibers according to the embodiment. FIG. 5 is a diagram for explaining protection control when an arc flash occurs according to the embodiment. Omit cross-sectional hatching.

FIGS. 4A and 4B show examples of the arrangement of semiconductor switching elements for each phase of the inverter 150. On the plane of the heat sink, switches QU1 to QU4 related to the U phase are arranged at appropriate distances. Each of the switches QU1 to QU4 is configured as a module. A bus bar (not shown) or the like is used for electrical connection between modules. For example, terminals provided at the top of the switches QU1 to QU4 are connected by a bus bar. The switches QV1 to QV4 related to the V phase and the switches QW1 to QW4 related to the W phase are the same as the switches QU1 to QU4 related to the U phase.

The optical fiber 26 is placed near the position where each of the above modules is placed. For example, the optical fiber 26 is held near the semiconductor switching elements of each phase so as to extend in an arc. For example, it is preferable that the optical fibers 26 are wound a plurality of times to form a bundle, and the bundled portion is placed near each module. Instead of gathering them into a bundle, they may be drawn in a meandering arc, or may be formed into a U-shape in which a straight section and this section are combined.

The optical fiber 26 arranged as described above is in a position where the light generated due to the accident inside the inverter 150 can be taken in with its side surface 261SS. When arranged in this way, the light that can be taken in by the optical fiber 26 includes the light from the switches QU1 to QU4 of the inverter 150. Switches QU1 to QU4 of inverter 150 are examples of semiconductor switching elements of a power converter. The V phase and the W phase may also be configured in the same manner as the U phase. In this case, bundles of optical fibers 26 are provided separately for each phase, but each bundle is composed of a common optical fiber 26.

For example, the semiconductor switching element of the power converter and the conductor portion of the power converter are placed together with the optical fiber 26 in a housing surrounded by a light-shielding member. For example, the housing 150B accommodates a range indicated by the reference numeral 150.
More specifically, the switches QU1 to QU4 of the inverter 150 and the conductor portion of the inverter 150 are arranged together with the optical fiber 26 in a housing surrounded by a light-shielding member.
In this case, it is desirable that no light-shielding member be provided between the switches QU1 to QU4 of the inverter 150 and the optical fiber 26 or between the conductor portion of the inverter 150 and the optical fiber 26.
If the brightness around the optical fiber during normal times is relatively dark, more specifically, if there is no light due to arc flash or the like during normal times, the amount of light detected by the OE unit 25 will be the same as that caused by arc flash. The amount of light is much smaller than the amount of light when it was generated. This lack of influence from other light makes it easier to detect the occurrence of arc flash.

The optical fiber 26 arranged as described above extends in an arc with a curvature larger than a predetermined curvature. The predetermined curvature is defined using, for example, a "minimum radius of curvature" from the viewpoint of the strength, transmission loss, etc. of the optical fiber 26.

The optical fiber 26 is preferably arranged so that it can receive light from outside the arc. This arrangement position relationship may be defined as follows.

For example, when the optical fiber 26 is arranged as shown in FIGS. 4A and 4B, the position of the arc and the position of each semiconductor switching element such as the switches QU1 to QU4 of the inverter 150 are determined with respect to the plane F corresponding to the arc. On the plane F, images projected from each semiconductor switching element on the outside of the arc are placed on the plane F.
Note that the above-mentioned arrangement relationship is an example of an arrangement that makes it easier to detect light due to arc flash, and is not limited to this, and can be changed as appropriate.

With reference to FIG. 5, protection control when an arc flash occurs according to the embodiment will be described.
FIG. 5 is a diagram for explaining protection control when an arc flash occurs according to the embodiment. For example, protection control is implemented in the following situations.

(1) A plurality of semiconductor switching elements are connected in cascade for each phase.
For example, as shown in FIG. 1 described above, in the U phase, switches QU1 and QU2 form a positive side arm, and switches QU3 and QU4 form a negative side arm. In the V phase, switches QV1 and QV2 form a positive arm, and switches QV3 and QV4 form a negative arm. In the W phase, switches QW1 and QW2 form a positive arm, and switches QW3 and QW4 form a negative arm.
For example, if any of the semiconductor switching elements in the U-phase switches QU1 to QU4 is short-circuited, there is a risk that the positive and negative arms of the U-phase will short-circuit, resulting in short-circuit damage to the U-phase. . Hereinafter, a case where the U phase is used as the accident phase will be explained as an example.

(2) Due to a short-circuit failure in the U phase, a fault current flows through the positive and negative arms of the U phase, causing the U phase conductor (bus) or any of the switches QU1 to QU4 to melt, causing an arc flash. There are cases where The V phase and W phase at this stage are healthy phases.
For example, until one of the fuses 150UP and 150UN shown in FIG. 2 responds to the fault current and stops the fault current, the fault current continues to flow and an arc flash can occur in the U phase.

(3) In the above situation, when an arc flash occurs in the U phase, the amount of light taken into the optical fiber 26 increases. Accordingly, the amount of light reaching the OE unit 25 via the optical fiber 26 increases. OE unit 25 detects this and outputs gate block signal GB3.

(4) The GB unit 22 (FIG. 2) detects the gate block signal GB3 and limits the output of the gate pulse GP2 of all phases. As a result, the gate pulse (GP3) supplied to the inverter 150 disappears.

(5) The semiconductor switching elements of all phases of the inverter 150 are controlled to be turned off. As a result, the current flowing through each semiconductor switching element is cut off by each semiconductor switching element not only in the fault phase U phase but also in the healthy phase V phase and W phase.

Note that the protection circuit may cut off the fault current before the state (5) above is reached. In this case, since the accident point has already been isolated, the risk of the accident spreading is low. When the protection circuit responds and interrupts the fault current, the analysis unit 24 detects that the news has blown out from the state OC1 of the protection circuit and outputs a gate block signal GB2.

Even if the protection circuit of the fault phase is unable to cut off the fault current due to response delay, etc., if the above condition (5) occurs, the operation related to power conversion in the inverter 150 cannot be stopped. can. As a result, at least the semiconductor switching element in the healthy phase is not controlled to be turned on, and it is possible to prevent abnormal current from flowing in the healthy phase.

According to the above procedure, the gate block signal GB3 is generated before the gate block signal GB2. The GB unit 22 detects the gate block signal GB2, but continues to limit the output of gate pulses of all phases, which has already been set based on the gate block signal GB3.

In this embodiment, by using the gate block signal GB3, it is possible to limit the output of gate pulses of all phases at an earlier stage than starting to limit the output of gate pulses of all phases according to the state OC1 of the protection circuit. .

According to the above embodiment, the optical fiber 26 according to the control device 20 guides the light taken in by the side surface 261SS of the extending light guide section 261 in the extending direction, and outputs it from the ends 261PA and 261PB of the light guide section 261. is formed. The OE unit 25 detects the light guided to either end 261PA or 261PB of the light guide section 261. The GB unit 22 interrupts power conversion by the inverter 150 when the OE unit 25 detects light resulting from an accident involving an arc flash. Thereby, the occurrence of secondary failures due to accidents that cause arc flash can be prevented with a simple method.

Further, the power conversion device 1 including the inverter 150 includes the control device 20 and the inverter 150. The GB unit 22 may use the light detection result by the OE unit 25 to control a semiconductor switching element related to power conversion of the inverter 150 to an OFF state, thereby interrupting the power conversion by the inverter 150.

(First modification of the embodiment)
A first modification will be described with reference to FIGS. 6A, 6B, and 7. In the embodiment described above, a case has been described in which one optical fiber 26 is used to collectively monitor and control three phases. In this modification, a case will be described in which three phases are collectively monitored and controlled using a pair of optical fibers 26A1 and 26A2.

FIG. 7 is a configuration diagram of a control device 20A according to a first modification of the embodiment.
The control device 20A includes a GB unit 22A (protection control section) and an OE unit 25A (light detection section) in place of the GB unit 22 and OE unit 25 of the control device 20.

The GB unit 22A further acquires the gate block signal GB4 and uses it in the same way as the gate block signal GB3. For example, when any of the gate block signals GB1, GB2, GB3, and GB4 is in a significant state, the GB unit 22A uses the gate pulse GP2 regardless of the signal state of the gate pulse GP1 supplied from the inverter control unit 21. Limits the output so that there are no pulses to output.

The OE unit 25A corresponds to a configuration including two systems of OE units 25. The OE unit 25A detects the light guided from the first optical fiber 26A1, and outputs a gate pulse GP3 indicating significance when detecting light exceeding a predetermined amount of light. The OE unit 25B detects the light guided from the second optical fiber 26A2, and outputs a gate pulse GP4 indicating significance when detecting light exceeding a predetermined amount of light.

FIG. 6A is a cross-sectional view showing the arrangement of optical fibers 26A1 and 26A2 in a first modification of the embodiment. FIG. 6B is a plan view showing the arrangement of optical fibers 26A1 and 26A2 in a first modification of the embodiment.
As shown in FIG. 6A, the optical fibers 26A1 and 26A2 were shifted in the normal direction of the plane FS and arranged so that their projected images onto the plane FS overlapped. Thereby, the optical fibers 26A1 and 26A2 can each take in the light of the arc flash.

As a result, in addition to producing the same effects as the embodiment, the arc flash detection system can be made redundant with a simple configuration.

(Second modification of embodiment)
A second modification will be described with reference to FIGS. 8A, 8B, and 9. In the embodiment described above, a case has been described in which one optical fiber 26 is used to collectively monitor and control three phases. In this modification, a case will be described in which the optical fibers 26B1, 26B2, and 26B3 are used to monitor each of the three phases and control the three phases collectively.

FIG. 9 is a configuration diagram of a control device 20B according to a second modification of the embodiment.
The control device 20B includes a GB unit 22B (protection control section) and an OE unit 25B (light detection section) in place of the GB unit 22 and OE unit 25 of the control device 20.

The GB unit 22B further acquires gate block signals GB4 and GB5 and uses them in the same way as gate block signal GB3. For example, when any of the gate block signals GB1, GB2, GB3, GB4, and GB5 is in a significant state, the GB unit 22B controls the gate block signal regardless of the signal state of the gate pulse GP1 supplied from the inverter control unit 21. The output of pulse GP2 is limited to a state where no pulse is output.

The OE unit 25B corresponds to a configuration including three systems of OE units 25. The OE unit 25B detects the light guided from the first optical fiber 26B1 corresponding to the U phase, and outputs a gate pulse GP3 indicating significance when detecting light exceeding a predetermined amount of light. The OE unit 25B detects the light guided from the second optical fiber 26B2 corresponding to the V phase, and outputs a gate pulse GP4 indicating significance when detecting light exceeding a predetermined amount of light. The OE unit 25B detects the light guided from the third optical fiber 26B3 corresponding to the W phase, and outputs a gate pulse GP5 indicating significance when detecting light exceeding a predetermined amount of light.

FIG. 8A is a cross-sectional view showing the arrangement of optical fibers 26B1, 26B2, and 26B3 in a second modification of the embodiment. FIG. 8B is a plan view showing the arrangement of optical fibers 26B1, 26B2, and 26B3 in a second modification of the embodiment.
As shown in FIG. 9, optical fibers 26B1, 26B2, and 26B3 were arranged in each phase. Thereby, the optical fibers 26B1, 26B2, and 26B3 can take in the light of the arc flash generated in each phase.

As a result, in addition to producing the same effects as the embodiment, the arc flash detection system can be configured separately for each phase with a simple configuration.

According to at least one embodiment described above, the power conversion control device includes an optical fiber, a light detection section, and a protection control section. The optical fiber is formed so that the light taken in by the side surface of the extending light guide section is guided in the extending direction, and is output from the end of the light guide section. The light detection section detects the light guided to the end of the light guide section. The protection control unit uses a protection method that interrupts power conversion by the power converter related to the optical fiber when the light detection unit detects light caused by an accident involving an arc flash. The occurrence of secondary failures caused by accidents can be prevented by a simple method.

According to at least one embodiment, the power conversion device includes a power conversion control device and a power converter. The protection control unit uses the light detection result to control a semiconductor switching element related to power conversion of the power converter to an OFF state, thereby interrupting power conversion by the power converter related to the optical fiber. Thereby, the power conversion device can prevent the occurrence of secondary failures due to accidents that cause arc flash using a simple method.

Several embodiments of the present invention have been described above, but 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 changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the claimed invention and its equivalents. Further, each of the embodiments described above can be implemented in combination with each other.

According to the above embodiment, it is preferable that the optical fiber for supplying the gate pulse to the inverter 150 has a light-shielding side surface.

1 Power conversion device, 20 Control device (power conversion control device), 21 Inverter control section, 22 GB unit (protection control section), 23 EO unit, 24 Analysis unit, 25 OE unit (light detection section), 26 Optical fiber, 150 inverter

Claims

an optical fiber formed so as to guide light taken in by a side surface of a stretching light guide in the stretching direction and output from an end of the light guide;
a light detection section that detects the light guided to the end of the light guide section;
a protection control unit that interrupts power conversion by a power converter related to the optical fiber when light caused by an accident involving an arc flash is detected by the light detection unit;
A power conversion control device comprising:
The optical fiber is
Taking in light outside the light guide in a portion where a shielding member is not provided on a side surface of the light guide;
The power conversion control device according to claim 1.
The optical fiber is
disposed at a position where light generated due to an accident within the power converter can be taken in on a side surface of the light guide section;
The power conversion control device according to claim 1.
The optical fiber is
The stretching draws an arc with a curvature larger than a predetermined curvature,
A projected image obtained by projecting the position of the arc and the position of the semiconductor switching element of the power converter in the normal direction of the plane onto a plane corresponding to the arc is a projection image of the semiconductor switching element on the outside of the arc on the plane. An image projected from the switching element is arranged.
The power conversion control device according to claim 3.
The optical fiber is
It is formed to capture light due to an arc flash generated from a semiconductor switching element of the power converter or a conductor portion for causing current to flow through the semiconductor switching element.
The power conversion control device according to claim 1.
The power conversion control device according to claim 4 or claim 5,
a power converter related to the optical fiber;
Equipped with
The protection control section includes:
using the light detection result to control a semiconductor switching element related to power conversion of the power converter to an OFF state to interrupt power conversion by the power converter;
Power converter.
The protection control section includes:
Based on the light detection result, suspending power conversion by the power converter with priority over control of an on/off state of a semiconductor switching element of the power converter related to continued operation;
The power conversion device according to claim 6.
A casing that houses the semiconductor switching element of the power converter, the conductor part of the power converter, and the optical fiber,
The power conversion device according to claim 6, wherein the casing is formed of a light-shielding member.
A method for protecting a power conversion device, the method comprising:
an optical fiber formed to guide light taken in by a side surface of a stretching light guide in the stretching direction and output from an end of the light guide;
a light detection section that detects the light guided to the end of the light guide section;
detecting light around the optical fiber using a
a step of interrupting power conversion by a power converter associated with the optical fiber when light caused by an accident involving an arc flash is detected by the light detection unit;
Protection methods including.