JP2018137910A - Electric current cut-off circuit and power conversion unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a cut-off relay part that cuts off a cable way in both a case when an electrical leakage state is generated and a case when an abnormal state other than the electrical leakage state is generated.SOLUTION: A first switching element 161 is connected to a second connection point 192, is subjected to on-off control by an electrical leakage detection circuit 150, and turns off a first opening-and-closing part 111 when detecting the electrical leakage of an electric power converter 200. A second switching element 162 is connected to the second connection point 192, is subjected to on-off control by the electric power converter 200, and turns off the first opening-and-closing part 111 when the electric power converter 200 is subjected to parallel off from a system 400. A first anode 171a is connected to a secondary side part 132. A first cathode 171c is connected to a first connection point 191. A second anode 172a is connected to a control power supply 250 of the electric power converter 200. A second cathode 172c is connected to the first connection point 191.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a current interrupt circuit and a power conversion unit.

  An interruption relay unit for interrupting an electric circuit when electric leakage occurs is known. Patent Document 1 describes an example of such a cut-off relay unit.

JP 59-6718

  There are other electrical anomalies besides electrical leakage. Even when an abnormality other than leakage occurs, there are cases where the electric circuit should be interrupted. However, if the interrupting relay part for interrupting the electric circuit when an electric leakage occurs and the interrupting relay part for interrupting the electric circuit when an abnormality other than the electric leakage occurs are provided separately, the circuit scale increases. In addition, if these relay units are provided separately, costs increase.

  Therefore, an object of the present disclosure is to realize a cut-off relay unit that cuts off an electric circuit both when a leakage occurs and when an abnormality other than a leakage occurs.

This disclosure
A current interruption circuit of a power conversion device linked to a grid,
A first opening / closing unit that detachably connects the system and the power converter, and a first control unit that is connected between a first connection point and a second connection point and drives the first opening / closing unit. A first interrupting relay unit;
An insulated power supply including a primary side portion to which an AC voltage is applied by the system, and a secondary side portion that operates at a reference potential of the power converter;
An electric leakage detection circuit that is supplied with electric power from the secondary side portion, operates at the reference potential, and detects electric leakage of the power conversion device;
A first switching element that is connected to the second connection point, is on / off controlled by the leakage detection circuit, and turns off the first opening / closing unit in cooperation with the first control unit when leakage detection of the power converter is performed;
Second connected to the second connection point, controlled to be turned on / off by the power converter, and turned off the first opening / closing part in cooperation with the first controller when the power converter is disconnected from the grid. A switching element;
A first backflow prevention diode including a first anode and a first cathode, wherein the first anode is connected to the secondary portion, and the first cathode is connected to the first connection point;
A second backflow prevention diode including a second anode and a second cathode, wherein the second anode is connected to a control power source of the power converter, and the second cathode is connected to the first connection point. In addition, a current interruption circuit is provided.

  According to the technology according to the present disclosure, it is possible to realize a cut-off relay unit that cuts off an electric circuit both when a leakage occurs and when an abnormality other than a leakage occurs.

FIG. 1 is a diagram for explaining a configuration of a current interrupt circuit according to the embodiment. FIG. 2 is a diagram for explaining the operation of the current interrupt circuit of FIG. FIG. 3 is a diagram for explaining the operation of the current interrupt circuit of FIG. FIG. 4 is a diagram for explaining the operation of the current interrupt circuit of FIG. FIG. 5 is a diagram for explaining a configuration of a current interrupt circuit according to a comparative embodiment.

The first aspect of the present disclosure is:
A current interruption circuit of a power conversion device linked to a grid,
A first opening / closing unit that detachably connects the system and the power converter, and a first control unit that is connected between a first connection point and a second connection point and drives the first opening / closing unit. A first interrupting relay unit;
An insulated power supply including a primary side portion to which an AC voltage is applied by the system, and a secondary side portion that operates at a reference potential of the power converter;
An electric leakage detection circuit that is supplied with electric power from the secondary side portion, operates at the reference potential, and detects electric leakage of the power conversion device;
A first switching element that is connected to the second connection point, is on / off controlled by the leakage detection circuit, and turns off the first opening / closing unit in cooperation with the first control unit when leakage detection of the power converter is performed;
Second connected to the second connection point, controlled to be turned on / off by the power converter, and turned off the first opening / closing part in cooperation with the first controller when the power converter is disconnected from the grid. A switching element;
A first backflow prevention diode including a first anode and a first cathode, wherein the first anode is connected to the secondary portion, and the first cathode is connected to the first connection point;
A second backflow prevention diode including a second anode and a second cathode, wherein the second anode is connected to a control power source of the power converter, and the second cathode is connected to the first connection point. In addition, a current interruption circuit is provided.

  According to the technique according to the first aspect, it is possible to realize a cutoff relay unit that cuts off the electric circuit both when an electric leakage occurs and when an abnormality other than the electric leakage occurs.

The second aspect of the present disclosure includes, in addition to the first aspect,
The system is a single-phase three-wire system,
The primary side portion is provided with a current interruption circuit to which an AC voltage between the U phase and the W phase of the system is applied.

  From the viewpoint of the system, the insulated power source is a load. In a 2nd aspect, the alternating voltage between the U phase of a system | strain and a W phase is applied to the primary side part of an insulated power supply. If it does in this way, it will be easy to balance the load between each phase of a system. This makes it easy to meet grid connection requirements.

The third aspect of the present disclosure, in addition to the first aspect or the second aspect,
The isolated power supply provides a current interrupt circuit including an isolation transformer and a rectifier circuit.

  According to the insulated power supply of a 3rd aspect, the direct current voltage used for the drive of a 1st interruption | blocking relay part and a leakage detection circuit can be easily produced | generated from the alternating voltage of a system | strain.

  When an AC voltage between the U phase and W phase of the system is applied to the primary side portion as in the second mode, a high voltage is applied to the primary side portion. However, according to the insulation transformer of the third aspect, a high voltage can be converted to a low voltage. For this reason, parts with high pressure resistance can be reduced or eliminated. This leads to cost reduction of the current interrupt circuit.

  Further, the current required for driving the first interrupting relay unit and the leakage detection circuit is small. For this reason, the insulation transformer itself can be configured at low cost.

The fourth aspect of the present disclosure includes, in addition to the first to third aspects,
Equipped with a zero-phase current transformer,
The leakage detection circuit provides a current interruption circuit that detects leakage of the power converter in cooperation with the zero-phase current transformer.

  If the zero-phase current transformer of the fourth aspect is used, the leakage detection can be suitably performed.

The fifth aspect of the present disclosure is:
Provided is a power conversion unit including any one of the current interrupting circuits according to the first to fourth aspects and the power conversion device.

  According to the 5th aspect, the power conversion unit which utilized the electric current interruption circuit of the 1st-4th aspect can be provided.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

  FIG. 1 shows a power conversion unit 300 of the present embodiment. The power conversion unit 300 includes a power conversion device 200. The power conversion device 200 is connected to the system 400. The power conversion unit 300 includes a current interrupt circuit 100.

[System 400]
In the present embodiment, the system 400 is a single-phase three-wire system. The system 400 has a U phase, a W phase, and an O phase. The U phase and the W phase are non-grounded phases. The O phase is a ground phase.

  The voltage between the U phase and the O phase is the first AC voltage. The voltage between the W phase and the O phase is the second AC voltage. The voltage between the U phase and the W phase is a third AC voltage applied. The first AC voltage and the second AC voltage are voltages with opposite phases. The effective value of the third AC voltage is twice the effective value of the first AC voltage and twice the effective value of the second AC voltage. Typically, the effective value of the first AC voltage and the second AC voltage is 100V. The effective value of the third AC voltage is 200V.

[Power Converter 200]
In the present embodiment, the power conversion device 200 is connected to a DC power source (not shown). The power conversion device 200 converts the DC power of the DC power source into AC power. The direct current power source is, for example, a fuel cell.

In the present embodiment, the power conversion device 200 includes a switching circuit 210. A DC voltage V _dc1 is applied to the power converter 200 from the control power source 250. The switching circuit 210 performs the power conversion using the DC voltage V _dc1 .

  Any power source can be used as the control power source 250. The control power source 250 can be realized using, for example, a fuel cell or a storage battery.

  In the present embodiment, the power conversion device 200 includes a power failure detection circuit 220. The power failure detection circuit 220 detects a power failure in the system 400 using a detection value of a sensor (not shown).

  The specific mode of power failure detection by the power failure detection circuit 220 is not particularly limited. In one example, a voltage sensor detects a voltage between two phases selected from the U phase, W phase, and O phase of the system 400. The power failure detection circuit 220 detects a zero cross point from the detection value of the voltage sensor. When the next zero cross point cannot be detected for a predetermined time or more after the zero cross point is detected at a certain time, the power failure detection circuit 220 determines that a power failure has occurred. In another example, it is determined whether or not a power failure has occurred based on the magnitude of the voltage obtained from the detected value.

  In the present embodiment, the power conversion device 200 is connected to the system 400 by an AC electrical path 401. Specifically, the AC circuit 401 is a three-phase circuit, and includes a U-phase circuit 401U, a W-phase circuit 401W, and an O-phase circuit 401O. A first AC voltage is applied between the U-phase electric circuit 401U and the O-phase electric circuit 401O. A second AC voltage is applied between the W-phase electric circuit 401W and the O-phase electric circuit 401O. A third AC voltage is applied between the U-phase circuit 401U and the W-phase circuit 401W.

[Current interrupting circuit 100]
In the present embodiment, the current interrupt circuit 100 includes a first interrupt relay unit 110, a second interrupt relay unit 120, an insulated power source 130, a zero-phase current transformer 140, a leakage detection circuit 150, and a first switching element. 161, a second switching element 162, a third switching element 163, a first backflow prevention diode 171, and a second backflow prevention diode 172.

(First cutoff relay unit 110)
In the present embodiment, the first cutoff relay unit 110 includes a U-phase relay 110U, a W-phase relay 110W, and an O-phase relay 110O. Relays 110U, 110W and 110O are mechanical relays. Relays 110U, 110W and 110O are normally closed relays.

  U-phase relay 110U includes U-phase switch 111U and U-phase controller 112U. W-phase relay 110W includes a W-phase switch 111W and a W-phase controller 112W. The O-phase relay 110O includes an O-phase switch 111O and an O-phase controller 112O.

  The U-phase switch 111U connects the system 400 and the power conversion device 200 in a detachable manner in the U-phase electric circuit 401U. W-phase switch 111W connects system 400 and power conversion device 200 in a detachable manner in W-phase electric circuit 401W. The O-phase switch 111O connects the system 400 and the power converter 200 so as to be detachable in the O-phase electric circuit 401O.

  The U-phase controller 112U is connected between the first connection point 191 and the second connection point 192. The W-phase controller 112W is connected between the first connection point 191 and the second connection point 192. The O-phase controller 112O is connected between the first connection point 191 and the second connection point 192. The controllers 112U, 112W and 112O are connected in parallel between the first connection point 191 and the second connection point 192.

  U-phase controller 112U drives U-phase switch 111U. W-phase controller 112W drives W-phase switch 111W. The O-phase controller 112O drives the O-phase switch 111O.

  Hereinafter, the U-phase switch 111U, the W-phase switch 111W, and the O-phase switch 111O may be collectively referred to as the first switch 111. The U-phase controller 112U, the W-phase controller 112W, and the O-phase controller 112O may be collectively referred to as the first controller 112.

  When collectively referred to as described above, the first interrupting relay unit 110 can be expressed as having the first opening / closing unit 111 and the first control unit 112. The first opening / closing unit 111 can be expressed as the system 400 and the power conversion device 200 being detachably connected. The first control unit 112 can be expressed as being connected between the first connection point 191 and the second connection point 192. The first control unit 112 can be expressed as driving the first opening / closing unit 111.

(Second interruption relay unit 120)
In the present embodiment, the second cutoff relay unit 120 includes a U-phase relay 120U, a W-phase relay 120W, and an O-phase relay 120O. Relays 120U, 120W and 120O are mechanical relays. Relays 120U, 120W and 120O are normally closed relays.

  U-phase relay 120U includes U-phase switch 121U and U-phase controller 122U. W-phase relay 120W includes a W-phase switch 121W and a W-phase controller 122W. O-phase relay 120O includes an O-phase switch 121O and an O-phase controller 122O.

  The U-phase switch 121U connects the system 400 and the power conversion device 200 in a detachable manner in the U-phase electric circuit 401U. W-phase switch 121W connects system 400 and power conversion device 200 in a detachable manner in W-phase electric circuit 401W. The O-phase switch 121O connects the system 400 and the power conversion device 200 so as to be detachable in the O-phase electric circuit 401O.

  The U-phase controller 122U is connected between the third connection point 193 and the fourth connection point 194. The W-phase controller 122W is connected between the third connection point 193 and the fourth connection point 194. The O-phase controller 122O is connected between the third connection point 193 and the fourth connection point 194. The controllers 122U, 122W and 122O are connected in parallel between the third connection point 193 and the fourth connection point 194.

  U-phase controller 122U drives U-phase switch 121U. W-phase controller 122W drives W-phase switch 121W. The O-phase controller 122O drives the O-phase switch 121O.

  Hereinafter, the U-phase switch 121U, the W-phase switch 121W, and the O-phase switch 121O may be collectively referred to as the second switch 121. The U-phase controller 122U, the W-phase controller 122W, and the O-phase controller 122O may be collectively referred to as the second control unit 122.

  When generically referred to as described above, the second cutoff relay unit 120 can be expressed as having the second opening / closing unit 121 and the second control unit 122. The 2nd opening-and-closing part 121 can be expressed as connecting system 400 and power converter 200 so that separation is possible. The second control unit 122 can be expressed as being connected between the third connection point 193 and the fourth connection point 194. The second control unit 122 can be expressed as driving the second opening / closing unit 121.

(Insulated power supply 130)
The insulated power supply 130 includes a primary side portion 131 and a secondary side portion 132. The primary side portion 131 is a so-called charging unit. The secondary part 132 is a so-called non-charging part. The primary side part 131 and the secondary side part 132 are insulated from each other.

The primary side part 131 is connected to the alternating current circuit 401. Specifically, the primary side portion 131 is connected to a U-phase electric circuit 401U and a W-phase electric circuit 401W. An AC voltage is applied to the primary side portion 131 by the system 400. Specifically, an AC voltage V _ac1 between the U phase and the W phase of the system 400 is applied to the primary side portion 131. The AC voltage V _ac1 is the third AC voltage described above.

  The secondary side portion 132 operates at the reference potential of the power conversion device 200. Note that the reference potential may not be the ground potential.

In the present embodiment, the insulated power supply 130 includes an insulating transformer 133 and a rectifier circuit 135. The insulating transformer 133 includes a primary side winding 133a and a secondary side winding 133b. An AC voltage V _ac1 is applied to the primary winding 133a. Isolation transformer 133 steps down the AC voltage V _ac1 to the AC voltage V _ac2. The AC voltage V _ac2 is output to the secondary winding 133b. The rectifier circuit 135 converts the AC voltage V _ac2 into a DC voltage V _dc1 .

In the present embodiment, the rectifier circuit 135 includes a diode 137 and a capacitor 138. The diode 137 has an anode 137a and a cathode 137c. The secondary winding 133b, the anode 137a, the cathode 137c, and the capacitor 138 are arranged in this order. The diode 137 rectifies the AC voltage V _ac2 . Capacitor 138 smoothes the output voltage from diode 137. As a result, a DC voltage V _dc1 appears between one end 138m and the other end 138n of the capacitor 138. In short, the diode 137 and the capacitor 138 generate a DC voltage V _dc1 by half-wave rectification.

(Zero phase current transformer 140)
In the present embodiment, the zero-phase current transformer 140 is located at a position between the first cutoff relay unit 110 and the power conversion device 200 in the AC circuit 401, specifically, the first cutoff relay unit 110 and the second cutoff relay. It is provided at a position between the parts 120. More specifically, at this position, three electric circuits 401U, 401W and 401O of U phase, W phase and O phase are inserted into the annular core of the zero-phase current transformer 140.

(Leakage detection circuit 150)
The leakage detection circuit 150 detects a leakage of the power conversion device 200. The leakage detection circuit 150 is connected to the secondary side portion 132. The leakage detection circuit 150 is supplied with electric power and a DC voltage V _dc1 from the secondary side portion 132. The leakage detection circuit 150 operates at the reference potential of the power conversion device 200. In the present embodiment, the leakage detection circuit 150 detects a leakage of the power conversion device 200 in cooperation with the zero-phase current transformer 140. Specifically, leakage detection circuit 150 detects a leakage of power conversion device 200 using the detected value of zero-phase current transformer 140.

(First switching element 161)
In the present embodiment, the first switching element 161 is connected to the leakage detection circuit 150 and the second connection point 192. Specifically, the control terminal 161 c of the first switching element 161 is connected to the leakage detection circuit 150. The high voltage side terminal 161 a of the first switching element 161 is connected to the second connection point 192.

  The first switching element 161 is ON / OFF controlled by the leakage detection circuit 150. The first switching element 161 turns off the first opening / closing unit 111 in cooperation with the first control unit 112 when the electric leakage of the power conversion device 200 is detected. As described above, this leakage detection can be performed using the detected value of the zero-phase current transformer 140 in the leakage detection circuit 150.

  Specifically, the first switching element 161 cooperates with the U-phase controller 112U to turn off the U-phase switch 111U and cooperates with the W-phase controller 112W when the power converter 200 detects a leakage. The W-phase switch 111W is turned off, and the O-phase switch 111O is turned off in cooperation with the O-phase controller 112O.

  A known element can be used as the first switching element 161. In the present embodiment, the first switching element 161 is a MOSFET (Metal-Oxide-Semiconductor-Field-Effect-Transistor), specifically an N-channel MOSFET. The high voltage side terminal 161a is a drain terminal. The low voltage side terminal 161b is a source terminal. The control terminal 161c is a gate terminal. Another example of the first switching element 161 is a bipolar transistor.

(Second switching element 162)
In the present embodiment, the second switching element 162 is connected to the power conversion device 200 and the second connection point 192. Specifically, the control terminal 162 c of the second switching element 162 is connected to the power conversion device 200. The high-voltage side terminal 162 a of the second switching element 162 is connected to the second connection point 192.

  The second switching element 162 is on / off controlled by the power converter 200. The second switching element 162 turns off the first opening / closing unit 111 in cooperation with the first control unit 112 when the power conversion device 200 is disconnected from the system 400.

  Specifically, when the power converter 200 is disconnected from the system 400, the second switching element 162 cooperates with the U-phase controller 112U to turn off the U-phase switch 111U, and the W-phase controller 112W. The W-phase switch 111W is turned off in cooperation with the O-phase switch, and the O-phase switch 111O is turned off in cooperation with the O-phase controller 112O.

  In the present embodiment, the second switching element 162 disconnects the power conversion device 200 from the system 400 when a power failure is detected. As described above, this power failure detection can be performed using a detection value of a voltage sensor (not shown) in the power failure detection circuit 220.

  A known element can be used as the second switching element 162. In the present embodiment, the second switching element 162 is a MOSFET, specifically, an N-channel MOSFET. The high voltage side terminal 162a is a drain terminal. The low voltage side terminal 162b is a source terminal. The control terminal 162c is a gate terminal. Another example of the second switching element 162 is a bipolar transistor.

(Third switching element 163)
In the present embodiment, the third switching element 163 is connected to the power conversion device 200 and the fourth connection point 194. Specifically, the control terminal 163 c of the third switching element 163 is connected to the power conversion device 200. The high-voltage side terminal 163 a of the third switching element 163 is connected to the fourth connection point 194.

  The third switching element 163 is on / off controlled by the power conversion device 200. The third switching element 163 cooperates with the second control unit 122 to turn off the second opening / closing unit 121 when the power conversion device 200 is disconnected from the system 400.

  Specifically, the third switching element 163 turns off the U-phase switch 121U in cooperation with the U-phase controller 122U when the power conversion device 200 is disconnected from the system 400, and the W-phase controller 122W. The W-phase switch 121W is turned off in cooperation with the O-phase switch, and the O-phase switch 121O is turned off in cooperation with the O-phase controller 122O.

  In the present embodiment, the third switching element 163 disconnects the power conversion device 200 from the system 400 when a power failure is detected.

  A known element can be used as the third switching element 163. In the present embodiment, the third switching element 163 is a MOSFET, specifically, an N-channel MOSFET. The high voltage side terminal 163a is a drain terminal. The low voltage side terminal 163b is a source terminal. The control terminal 163c is a gate terminal. Another example of the third switching element 163 is a bipolar transistor.

(Backflow prevention diodes 171 and 172)
The first backflow prevention diode 171 includes a first anode 171a and a first cathode 171c. The first anode 171 a is connected to the secondary side portion 132. The first cathode 171 c is connected to the first connection point 191.

  The second backflow prevention diode 172 includes a second anode 172a and a second cathode 172c. The second anode 172 a is connected to the control power source 250 of the power conversion device 200. The second cathode 172c is connected to the first connection point 191.

[Element connection]
In the present embodiment, the cathode 137c of the diode 137, the one end 138m of the capacitor 138, the one end 150m of the leakage detection circuit 150, and the first anode 171a of the first backflow prevention diode 171 are connected to the same potential. The first cathode 171c and the second cathode 172c are connected to the same potential. However, if necessary, other elements may be interposed between the illustrated elements.

  In the present embodiment, the other end 138n of the capacitor 138, the other end 150n of the leakage detection circuit 150, the low voltage side terminal 161b of the first switching element 161, the low voltage side terminal 162b of the second switching element 162, and the low voltage of the third switching element 163. The side terminal 163b is connected to the reference potential of the power conversion device 200.

[Operation of current interrupt circuit 100]
Hereinafter, the operation of the current interrupt circuit 100 will be described with reference to FIGS. In a part of FIGS. 3 and 4, a part drawn by a thin line in FIG. 2 is thickened. The thickened portion is a portion where current flows.

(When there is no power failure or leakage)
FIG. 2 shows the power conversion unit 300 when the system 400 is not out of power and no power leakage occurs in the power conversion device 200.

  In this case, a signal (ON signal) for turning on the first switching element 161 is not supplied to the control terminal 161c. A signal (ON signal) for turning on the second switching element 162 is not supplied to the control terminal 162c. Further, the control terminal 163c is not supplied with a signal for turning on the third switching element 163 (ON signal). In the present embodiment, the ON signal is a voltage wave that makes the inter-terminal voltage between the control terminal and the low-voltage side terminal larger than the threshold value.

  Since the on signal is not supplied, the switching elements 161, 162 and 163 are off. Therefore, no current flows through the control units 112 and 122. Specifically, no current flows through the controllers 112U, 112W, 112O, 122U, 122W and 122O.

  Since no current flows through the control units 112 and 122, the open / close units 111 and 121 are on. Specifically, the switches 111U, 111W, 111O, 121U, 121W and 121O are on. For this reason, the electrical connection of the system | strain 400 and the power converter device 200 is maintained.

(When power failure occurs)
FIG. 3 shows the power conversion unit 300 in a case where the system 400 has a power failure and no power leakage has occurred in the power conversion device 200.

  In this case, a signal (ON signal) for turning on the second switching element 162 is supplied from the power conversion device 200 to the control terminal 162c. Further, a signal (ON signal) for turning on the third switching element 163 is supplied from the power conversion device 200 to the control terminal 163c.

  Since the on signal is supplied, the switching elements 162 and 163 are on. Therefore, a current flows through the control units 112 and 122. Specifically, a current flows through the controllers 112U, 112W, 112O, 122U, 122W and 122O. The control power 250, the third connection point 193, the second anode 172a, the second cathode 172c, the first connection point 191, the first control unit 112, the second connection point 192, the high voltage side terminal 162a and the low voltage side terminal 162b. It flows in the order. The current flows in the order of the control power supply 250, the third connection point 193, the second control unit 122, the fourth connection point 194, the high-voltage side terminal 163a, and the low-voltage side terminal 163b.

  Since current flows through the control units 112 and 122, the open / close units 111 and 121 are turned off. Specifically, the switches 111U, 111W, 111O, 121U, 121W and 121O are turned off. For this reason, the electrical connection of the system | strain 400 and the power converter device 200 is interrupted | blocked.

(When electric leakage occurs)
FIG. 4 shows the power conversion unit 300 in a case where the grid 400 is not out of power and a power leak occurs in the power conversion device 200.

  In this case, a signal (ON signal) for turning on the first switching element 161 is supplied to the control terminal 161c.

  Since the on signal is supplied, the first switching element 161 is on. Accordingly, a current flows through the first control unit 112. Specifically, a current flows through the controllers 112U, 112W and 112O. The current flows in the order of the system 400, the insulated power supply 130, the first anode 171a, the first cathode 171c, the first connection point 191, the first control unit 112, the second connection point 192, the high-voltage side terminal 161a, and the low-voltage side terminal 161b. .

  Since a current flows through the first control unit 112, the first opening / closing unit 111 is turned off. Specifically, the switches 111U, 111W, and 111O are turned off. For this reason, the electrical connection of the system | strain 400 and the power converter device 200 is interrupted | blocked.

[Advantages of the current interrupt circuit 100 over the current interrupt circuit 500]
FIG. 5 shows a current interrupt circuit 500 according to a comparative embodiment. Hereinafter, advantages of the current interrupt circuit 100 over the current interrupt circuit 500 will be described.

  Similar to the current interrupt circuit 100, in the current interrupt circuit 500, the first interrupt relay unit 110 interrupts the electric circuit 401 when the system 400 fails. However, unlike the current interrupting circuit 100, in the current interrupting circuit 500, when an electric leakage occurs in the power conversion device 200, the interrupting relay unit 510, not the first interrupting relay unit 110, interrupts the electric circuit 401. In the current interrupt circuit 500, the number of the interrupt relay units is larger than the current interrupt circuit 100 by the number of the interrupt relay units 510. Conversely, the current interrupt circuit 100 has fewer interrupt relay units than the current interrupt circuit 500. This means that the current interrupt circuit 100 is more advantageous than the current interrupt circuit 500 in terms of cost.

In the current interrupt circuit 500, the AC voltage V _ac1 between the U phase and the W phase of the system 400 is used to obtain electric power necessary for driving the leakage detection circuit 150 and the interrupt relay unit 510. In this way, it is easy to balance the loads between the phases of the system 400. However, in the current interruption circuit 500, the element group 530 generates a DC voltage to be supplied to the leakage detection circuit 150 and the interruption relay unit 510 from the AC voltage V _ac1 . Since the AC voltage V _ac1 is large, it is necessary to consider the withstand voltage and withstand power of the element group 530. In the example of FIG. 5, in the element group 530, the diode 535, the thyristor 536, and the capacitor 537 are high breakdown voltage elements. Resistors 531 and 532 are high power-resistant elements. The presence of the high withstand voltage element and the high withstand voltage element increases the cost of the current interrupt circuit 500. On the other hand, in the current interruption circuit 100, since a current required for driving the leakage detection circuit 150 and the first interruption relay unit 110 is small, an inexpensive transformer can be used as the insulating transformer 133. The rectifier circuit 135 can also be realized at a low cost. For this reason, according to the technology according to the present embodiment, the current interrupt circuit 100 can be realized at low cost while balancing the loads between the phases of the system 400 by using the AC voltage V _ac1 .

  In the current interrupt circuit 500, power loss occurs in the resistors 531 and 532 and the Zener diodes 533, 534U, 534W, and 534O. On the other hand, the current interrupt circuit 100 does not have elements corresponding to these elements. For this reason, the current interruption circuit 100 is more advantageous than the current interruption circuit 500 from the viewpoint of power loss suppression.

  Note that the power conversion unit 300 may be configured to disconnect the power conversion device 200 from the system 400 when another abnormality occurs instead of during the power failure of the system 400. For example, the power conversion unit 300 may be configured to disconnect the power conversion device 200 from the system 400 when an accident such as a short circuit or a disconnection occurs in the system 400. Such an accident can be detected by, for example, providing a current sensor in the AC circuit 401 to detect an overcurrent.

100 Current interrupt circuit 110, 120 Interrupt relay unit 110U, 110W, 110O, 120U, 120W, 120O Relay 111, 121 Switch unit 111U, 111W, 111O, 121U, 121W, 121O Switch 112, 122 Control unit 112U, 112W, 112O , 122U, 122W, 122O Controller 130 Insulation power supply 131 Primary side part 132 Secondary side part 133 Insulation transformer 133a, 133b Winding 135 Rectifier circuit 137, 171, 172 Diodes 137a, 171a, 172a Anode 137c, 171c, 172c Cathode 138 Capacitors 138m, 150m One end 138n, 150n The other end 140 Sensor 150 Leakage detection circuit 161, 162, 163 Switching element 161a, 162a, 163a High voltage side terminal 16 b, 162b, 163b Low voltage side terminals 161c, 162c, 163c Control terminals 191, 192, 193, 194 Connection point 200 Power conversion device 210 Switching circuit 220 Power failure detection circuit 250 Control power supply 300 Power conversion unit 400 System 401 Electric circuit 500 Current interruption circuit 510 Interrupting Relay Unit 530 Element Group 531, 532 Resistor 533, 534 U, 534 W, 534 O Zener Diode 535 Diode 536 Thyristor 537 Capacitor

Claims (5)

A current interruption circuit of a power conversion device linked to a grid,
A first opening / closing unit that detachably connects the system and the power converter, and a first control unit that is connected between a first connection point and a second connection point and drives the first opening / closing unit. A first interrupting relay unit;
An insulated power supply including a primary side portion to which an AC voltage is applied by the system, and a secondary side portion that operates at a reference potential of the power converter;
An electric leakage detection circuit that is supplied with electric power from the secondary side portion, operates at the reference potential, and detects electric leakage of the power conversion device;
A first switching element that is connected to the second connection point, is on / off controlled by the leakage detection circuit, and turns off the first opening / closing unit in cooperation with the first control unit when leakage detection of the power converter is performed;
Second connected to the second connection point, controlled to be turned on / off by the power converter, and turned off the first opening / closing part in cooperation with the first controller when the power converter is disconnected from the grid. A switching element;
A first backflow prevention diode including a first anode and a first cathode, wherein the first anode is connected to the secondary portion, and the first cathode is connected to the first connection point;
A second backflow prevention diode including a second anode and a second cathode, wherein the second anode is connected to a control power source of the power converter, and the second cathode is connected to the first connection point. Current interrupt circuit. The system is a single-phase three-wire system,
The current interrupt circuit according to claim 1, wherein an alternating voltage between a U phase and a W phase of the system is applied to the primary side portion.   The current interrupt circuit according to claim 1, wherein the insulated power source includes an insulating transformer and a rectifier circuit. Equipped with a zero-phase current transformer,
The current leakage detection circuit according to any one of claims 1 to 3, wherein the leakage detection circuit detects a leakage of the power converter in cooperation with the zero-phase current transformer.   The power conversion unit provided with the electric current interruption circuit as described in any one of Claims 1-4, and the said power converter device.

Images