JP2010213439A - System-cooperative inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system-cooperative inverter device improved in safety at the time of repair or replacement. <P>SOLUTION: The system-cooperative inverter device at least includes a boosting converter 104 converting a DC input voltage to a predetermined high voltage, an inverter 106 converting a DC output to an AC output, a smoothing capacitor 105 connecting the boosting converter 104 and the inverter 106, a disconnection means 108 disconnecting the output from the inverter 106 from a commercial AC 102, and a filter 107 comprising a reactor 113 connecting the disconnection means 108 and the inverter 106 and an output capacitor 117, and further includes a discharging means discharging the power stored in the smoothing capacitor 105. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a grid-connected inverter device that converts DC power, such as a fuel cell or a solar cell, into AC power and outputs the AC power linked to commercial AC.

  Conventionally, this type of grid-connected inverter device disconnects the grid-connected inverter device from commercial AC when the fuel cell, which is the DC input source, does not generate power or when an abnormality occurs in the grid-connected inverter device. (For example, refer to Patent Document 1).

  Below, the grid connection inverter apparatus described in patent document 1 is demonstrated using figures.

  FIG. 6 is a circuit block diagram of a conventional grid-connected inverter device.

  As shown in FIG. 6, the grid-connected inverter device 1 is connected to a commercial load 2 and connected to a domestic load 3 such as an air conditioner or a refrigerator. At this time, the commercial AC 2 and the grid-connected inverter device 1 are connected by a single-phase three-wire (UOW phase) AC 200V. The home load 3 is generally connected by a single-phase two-wire, and connection methods include AC 100V between U and O, AC 100V between W and O, and AC 200V between U and W.

  The grid-connected inverter device 1 includes at least a boost converter 4, a smoothing capacitor 5, an inverter 6, a filter 7, and a disconnecting relay 8. Here, the boost converter 4 includes an input capacitor 12 for smoothing an input voltage of the fuel cell 11, etc., an energy storage reactor 13, a boost converter switching element 14, and a boost diode 15, and the input voltage is derived from the system voltage. Boost to a high predetermined voltage.

  Further, the smoothing capacitor 5 smoothes and temporarily stores the boosted voltage. Further, the inverter 6 is constituted by a full bridge circuit using four switching elements Q1 to Q4, and outputs the electric power stored in the smoothing capacitor 5 as an AC sine wave synchronized with the commercial AC 2. The filter 7 includes a high frequency noise removing reactor 16 and an output capacitor 17 and removes high frequency noise superimposed on the output of the inverter 6.

  At this time, step-up converter switching element 14 and switching elements Q <b> 1 to Q <b> 4 operate based on the drive signal of control circuit 10. The disconnect relay 8 interconnects / disconnects the grid-connected inverter device 1 with the commercial AC 2.

  In general, the state connected to the commercial AC 2 is referred to as interconnection, and the disconnected state is referred to as disconnection.

  Further, an overvoltage detection circuit 9 is provided between the filter 7 and the disconnection relay 8 to detect line overvoltage between U-O and W-O. The disconnect relay 8 is driven by a signal from the control circuit 10 and a signal from the overvoltage detection circuit 9.

  Below, the operation | movement of the grid connection inverter apparatus in case both the fuel cell 11 and the commercial alternating current 2 are supplying electric power to the household load 3 is demonstrated concretely.

  First, as the input voltage of the inverter 6, when the voltage of the commercial alternating current 2 is AC 200V, the peak of the voltage reaches 283V, so that an input voltage higher than that is required. Specifically, in consideration of fluctuations in the voltage of the commercial alternating current 2, an input voltage of about DC350V is usually required.

  At this time, for example, when the fuel cell 11 having a rated output of about 40 V is used as an input power source, a boost of about 9 times is required. Therefore, the control circuit 10 turns on the boost converter switching element 14 to accumulate energy in the reactor 13, and the energy stored in the reactor 13 when the boost converter switching element 14 is turned off passes through the boost diode 15. It is stored in the smoothing capacitor 5 as electric power.

  By repeating the above operation at a high frequency, the voltage on the input side of the inverter 6 is boosted to about DC 350 V and maintained constant.

  Next, the inverter 6 outputs the electric power temporarily stored in the smoothing capacitor 5 as a substantially sine wave by causing the control circuit 10 to switch the four stone switching elements Q1 to Q4 at a high frequency. This substantially sine wave output current contains a high frequency component, but is smoothed by the high frequency noise removing reactor 16 and the output capacitor 17 of the filter 7 to be a smooth sine wave, which is kept closed by the control circuit 10. It is supplied to the home load 3 via the disconnection relay 8.

  When the fuel cell 11 finishes power generation, the disconnect relay 8 is held open by the control circuit 10, and the grid-connected inverter device 1 is disconnected from the commercial AC 2 and disconnected from the domestic load 3. It is. At this time, the boost converter switching element 14 and the switching elements Q1 to Q4 are all turned OFF, and the boost converter 4 and the inverter 6 stop operating.

Further, even when an abnormality occurs in the commercial AC 2 or the grid-connected inverter device 1 during the output of the grid-connected inverter device 1, it is disconnected from the commercial AC 2 and the household load 3 in the same manner as at the end of power generation. It is. For example, when an overvoltage occurs between U and O of the commercial AC 2, the overvoltage detection circuit 9 sends an overvoltage detection signal to the disconnecting relay 8 and the control circuit 10 when the voltage between U and O exceeds a certain threshold. . Upon receipt of the signal, disconnection relay 8 is held open, and boost converter 4 and inverter 6 are held stopped.
Japanese Patent Laid-Open No. 9-215025

  However, in the above-described conventional configuration, when the power generation of the fuel cell 11 ends or when the grid-connected inverter device 1 stops output due to some abnormality, the disconnect relay 8 is opened, It will be cut off. Therefore, the electric power stored in the smoothing capacitor 5 and the output capacitor 17 is held without being consumed. In particular, the smoothing capacitor 5 is in a state of being charged with a high voltage of about DC 350 V, and there is a problem that there is a possibility of electric shock when the grid-connected inverter device 1 is repaired and replaced.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a grid-connected inverter device with improved safety during repair / replacement work.

  In order to solve the above-described conventional problems, a grid-connected inverter device of the present invention includes a boost converter that converts a DC input voltage into a predetermined high voltage, an inverter that converts a DC output into an AC output, and the boost converter. A smoothing capacitor provided between the output side and the input side of the inverter for smoothing the output voltage of the boost converter; a disconnecting means for disconnecting the AC output of the inverter from commercial AC; and a reactor and an output capacitor And at least a filter provided between the disconnecting means and the inverter, and a discharging means for discharging the electric power stored in the smoothing capacitor.

  As a result, even when the disconnecting means is in an open state and the domestic load is disconnected from commercial AC, the power stored in the smoothing capacitor is consumed by the discharging means, thereby improving safety and reliability. System inverter device can be realized.

  The grid-connected inverter device of the present invention can consume the electric power stored in the smoothing capacitor by the internal discharging means even in the state disconnected from the load connected to the commercial AC. Therefore, even when power generation ends or when an abnormality occurs, the power stored in the smoothing capacitor can be reliably discharged even after the disconnecting means is opened and disconnected from the household load. As a result, it is possible to reduce the possibility of electric shock when repairing or replacing the grid-connected inverter device incorporated in the fuel cell power generation device or the like.

  A first invention is provided between a boost converter that converts a DC input voltage into a predetermined high voltage, an inverter that converts a DC output into an AC output, and an output side of the boost converter and an input side of the inverter. A smoothing capacitor for smoothing the output voltage of the boost converter, a disconnecting means for disconnecting the AC output of the inverter from commercial AC, a reactor and an output capacitor, and provided between the disconnecting means and the inverter. A grid-connected inverter device having a structure including at least a discharging unit that discharges the electric power stored in the smoothing capacitor.

  With this configuration, the power stored in the smoothing capacitor inside the grid-connected inverter device can be discharged even after the disconnecting means is opened and disconnected from the commercial AC. As a result, it is possible to realize a grid-connected inverter device with improved safety and reliability that reduces the possibility of electric shock in the repair / replacement of the grid-connected inverter device incorporated in a fuel cell power generator or the like.

  According to a second invention, in the first invention, there is provided prohibiting means for prohibiting the operation of the discharging means during the output operation of the inverter. As a result, when the grid-connected inverter device is linked to commercial AC and outputs power to a household load, the power consumption of the smoothing capacitor can be suppressed and the efficiency of the grid-connected inverter device can be improved. .

  According to a third invention, in the second invention, the prohibiting means is insulated from the discharging means. As a result, the prohibiting means can prevent the influence of commercial AC noise and the like and realize a stable circuit operation.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, there is provided an informing means for informing when the voltage of the smoothing capacitor is equal to or higher than a predetermined voltage. As a result, the operator can easily recognize that the smoothing capacitor is charged, and can be alerted to an electric shock or the like when repairing or replacing.

  According to a fifth invention, in the fourth invention, the notifying means is a light-emitting element whose luminance decreases as the voltage of the smoothing capacitor decreases. As a result, the voltage state of the smoothing capacitor can be reliably recognized, and the safety and workability during repair / replacement work of the grid-connected inverter device can be improved.

  According to a sixth invention, in the fourth or fifth invention, the boost converter is provided on a first substrate, the inverter is provided on a second substrate, and the notification means is provided on the first substrate. Thereby, even if the harness etc. which connect between 1st board | substrate and 2nd board | substrates are disconnected, it can alert | report that a smoothing capacitor is a charge state. As a result, the possibility of electric shock can be more reliably alerted to the repair / replacement operator of the grid-connected inverter device.

  In a seventh aspect based on any one of the first to sixth aspects, the boost converter is provided on the first substrate, the inverter is provided on the second substrate, and the discharging means is provided on the first substrate. Is. Thereby, even when the harness etc. which connect between 1st board | substrate and 2nd board | substrates are disconnected, the voltage of a smoothing capacitor can be discharged reliably. As a result, the risk of electric shock during repair / replacement work of the grid-connected inverter device can be more reliably reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the same components as those of the above-described embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
Below, the grid connection inverter apparatus in Embodiment 1 of this invention is demonstrated using figures.

  FIG. 1 is a circuit block diagram of a grid-connected inverter device according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram illustrating a discharge circuit to which the grid-connected inverter device according to Embodiment 1 of the present invention is connected.

  As shown in FIG. 1, the grid interconnection inverter device 101 includes at least a boost converter 104, a smoothing capacitor 105, an inverter 106, a filter 107, a disconnecting relay 108 that is a disconnecting means 108, and a discharge circuit 109. And in this Embodiment, the discharge circuit 109 is comprised by discharge resistance which is a discharge means, and discharge LED which is an alerting | reporting means. In the following description, the disconnecting means is described as the disconnect relay 108.

  Here, the boost converter 104 includes an input capacitor 112 for smoothing a DC input voltage such as the fuel cell 111, an energy storage reactor 113, a boost converter switching element 114, and a boost diode 115, and the input voltage is used as a system voltage. Boost to a higher predetermined voltage. The smoothing capacitor 105 smoothes and temporarily stores the boosted voltage.

  Inverter 106 is constituted by a full bridge circuit using four switching elements Q101 to Q104, and outputs the electric power stored in smoothing capacitor 105 as an AC sine wave synchronized with commercial AC 102. The filter 107 includes a high frequency noise removing reactor 116 and an output capacitor 117, and removes high frequency noise superimposed on the output of the inverter 106.

  At this time, boost converter switching element 114 and switching elements Q <b> 1 to Q <b> 4 operate based on the drive signal of control circuit 110. Further, the disconnect relay 108 interconnects / disconnects the grid interconnection inverter device 101 with the commercial AC 102.

  Further, a discharge circuit 109 is connected to the smoothing capacitor 105 in parallel with the inverter 106. At this time, as shown in FIG. 2, the discharge circuit 109 is composed of a discharge resistor 118 which is a discharge means connected in series and a discharge LED 119 which is a notification means. Then, when the household load 103 is disconnected from the commercial AC 102, the discharge circuit 109 discharges the electric power charged in the smoothing capacitor 105 as described below.

  And the grid connection inverter apparatus 101 of this Embodiment is connected with the household load 103, such as an air conditioner and a refrigerator, for example, in connection with the commercial alternating current 102. At this time, the commercial AC 102 and the grid-connected inverter device 101 are connected by a single-phase three-wire (UOW phase) AC 200V. In general, the household load 103 is connected by a single-phase two-wire, and connection methods include AC 100V between U and O, AC 100V between W and O, and AC 200V between U and W.

  The operation and action of the grid-connected inverter device 101 having the above configuration will be described in detail below.

  First, the operation when the fuel cell 111 supplies power to the household load 103 together with the commercial AC 102 will be described.

  First, when the voltage of the commercial alternating current 102 is AC 200V, the voltage peak is about 283V, and considering the fluctuation of the commercial alternating current 102, the voltage on the input side of the inverter 106 usually requires a voltage of about DC 350V. . Therefore, for example, when the fuel cell 111 is used as an input power source, when the rated output of the fuel cell 111 is, for example, about 40 V, it is necessary to increase the pressure about nine times.

  Specifically, first, the control circuit 110 turns on the step-up converter switching element 114 to accumulate energy in the reactor 113. When the boost converter switching element 114 is turned off, the energy stored in the reactor 113 is stored as electric power in the smoothing capacitor 105 via the boost diode 115.

  Further, by repeating the ON / OFF operation of the boost converter switching element 114 at a high frequency and storing power in the smoothing capacitor 105, the voltage on the input side of the inverter 106 is boosted to about DC 350 V and is made constant by the control circuit 110. Controlled to maintain.

  Next, the inverter 106 performs switching operation of the four stone switching elements Q101 to Q104 at a high frequency by the control circuit 110, and outputs the electric power temporarily stored in the smoothing capacitor 105 as a substantially sine wave. At this time, the high frequency component included in the substantially sine wave output current is smoothed by the filter 107 including the high frequency noise removing reactor 116 and the output capacitor 117 to become a smooth sine wave. Then, the smoothed sine wave is supplied to the home load 103 via the disconnecting relay 108 maintained in the closed state by the control circuit 110.

  The operation when power generation by the fuel cell 111 is completed will be described below.

  First, the control circuit 110 opens the disconnect relay 108. Thereby, the grid interconnection inverter device 101 is disconnected from the commercial AC 102 and the fuel cell 111 is disconnected from the domestic load 103.

  Then, boost converter switching element 114 and switching elements Q101 to Q104 are all turned OFF, and operation of boost converter 104 and inverter 106 is stopped. At this time, immediately after the grid-connected inverter device 101 is stopped, the smoothing capacitor 105 is charged with a voltage of about DC 350V.

  However, in the present embodiment, the electric power charged in the smoothing capacitor 105 can be discharged through the discharge resistor 118 of the discharge circuit 109. At this time, since a current flows through the discharge LED 119 via the discharge resistor 118, while the voltage remains in the smoothing capacitor 105, the discharge LED 119 emits light, which can be notified to an operator or the like.

  As the resistance value of the discharge resistor 118, a smaller value is preferable because the discharge time becomes shorter. However, since it also serves as a current limit of the discharge LED 119, it is set to about 35 kΩ, for example. Specifically, when the voltage of the smoothing capacitor 105 is DC 350 V, a current of 10 mA flows, and if the discharge progresses and the voltage decreases, the current value decreases in proportion thereto.

  At this time, as the voltage of the smoothing capacitor 105 decreases, the brightness of the discharge LED 119 decreases. When the voltage of the smoothing capacitor 105 decreases below the forward voltage of the discharge LED 119, for example, DC 1.5V, the light is turned off.

  Further, immediately after the grid-connected inverter device 101 is disconnected and stopped, power is stored not only in the smoothing capacitor 105 but also in the output capacitor 117, and a high voltage is maintained. Note that, during the output operation of the grid-connected inverter device 101, an AC voltage is applied to the output capacitor 117. Therefore, the voltage differs at each moment depending on the stop timing. For example, when the commercial AC 102 is AC 200 V, the voltage across the output capacitor 117 is about 0 to 283 V as an absolute value.

  At this time, the voltage of the output capacitor 117 can also be discharged by the discharge circuit 109 via the commutation diodes D101 and D104 of the switching elements Q101 and Q104, or via the commutation diodes D102 and D103 of the switching elements Q102 and Q103. Thereby, similarly to the smoothing capacitor 105, the voltage of the output capacitor 117 can also be reduced.

  As described above, according to the present embodiment, the electric power of the smoothing capacitor 105 and the output capacitor 117 is discharged from the discharge circuit 109 even when the household load 103 is disconnected from the commercial AC 102. It can be discharged through the resistor 118. As a result, it is possible to realize a grid-connected inverter device excellent in reliability and safety that reduces the possibility of electric shock when the grid-connected inverter device 101 is repaired or replaced.

  Further, according to the present embodiment, when the smoothing capacitor 105 and the output capacitor 117 are charged to DC 1.5V or more which is the forward voltage of the discharge LED 119, the discharge LED 119 is lit. As a result, by displaying and notifying that the smoothing capacitor 105 and the output capacitor 117 are at a high voltage, it is possible to alert the operator that there is a risk of electric shock.

  Further, according to the present embodiment, the luminance of the discharge LED 119 decreases as the voltage of the smoothing capacitor 105 and the output capacitor 117 decreases. As a result, it is possible to easily recognize the voltage drop condition, and thus a grid-connected inverter device with improved safety and workability at the time of repair and replacement can be realized.

(Embodiment 2)
Below, the grid connection inverter apparatus in Embodiment 2 of this invention is demonstrated using figures.

  FIG. 3 is a circuit block diagram of the grid-connected inverter device according to the second embodiment of the present invention. FIG. 4 is a circuit block diagram of discharge circuit 109 in the second embodiment of the present invention.

  That is, as shown in FIG. 3, in the present embodiment, the drive signal of the control circuit 110 is transmitted to the boost converter switching element 114, the switching elements Q101 to Q104, and the disconnecting relay 108 via the photocouplers PC101 to PC103. This is different from the first embodiment.

  Further, as shown in FIG. 4, a field effect transistor (FET) 120 is provided in the discharge circuit 109 as a switch for turning on / off the discharge resistor 118 and the discharge LED 119, and the control circuit 110 and the photocoupler are electrically used. It differs from the first embodiment in that it is insulated. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  Also in this embodiment, the discharge circuit 109 will be described with an example in which the discharge resistor 109 is a discharge unit and a discharge LED is a notification unit. Hereinafter, the field effect transistor 120 will be described as FET 120.

  As shown in FIG. 4, the voltage divided by the smoothing capacitor 105 by the voltage dividing resistors R122 and R123 is input to the gate terminal of the FET 120 of the discharge circuit 109. The collector terminal of the output transistor 125 of the inhibition signal photocoupler 124 is connected to the gate terminal of the FET 120.

  At this time, the anode side of the input side light emitting diode 126 of the prohibition signal photocoupler 124 is connected to the power line via the current limiting resistor 127, and the signal line of the control circuit 110 is connected to the cathode side.

  The operation and action of the grid-connected inverter device 101 having the above configuration will be described in detail below. Since the AC output operation of the grid-connected inverter device 101 is the same as that of the first embodiment, the operation of the different discharge circuit 109 will be mainly described.

  First, when the grid-connected inverter device 101 outputs in conjunction with the commercial AC 102, the control circuit 110 causes the input side light emitting diode 126 of the prohibition signal photocoupler 124 to emit light.

  As a result, the output transistor 125 is turned on, the potential difference between the gate terminal and the source terminal of the FET 120 of the discharge circuit 109 is forced to be zero, and the FET 120 is turned off. As a result, no current flows through the discharge resistor 118 of the discharge circuit 109, and the discharge LED 119 is not lit.

  On the other hand, when the grid-connected inverter device 101 is disconnected or stopped, the control circuit 110 turns off the input side light emitting diode 126.

  As a result, the output transistor 125 is turned OFF, and a voltage defined by the ratio of the voltage dividing resistors R122 and R123 is applied between the gate terminal and the source terminal of the FET 120 of the discharge circuit 109.

  Specifically, for example, R122: R123 = 1: 4. The values of the voltage dividing resistors R122 and R123 are preferably set to relatively large constants from the viewpoint of suppressing power consumption, for example, R122 = 1 MΩ and R123 = 4 MΩ. Hereinafter, this resistance value will be described as an example.

  At this time, immediately after the grid-connected inverter device 101 is stopped, the smoothing capacitor 105 stores electric power for maintaining a voltage of DC 350V. Therefore, a voltage of 70 V (= 350 V × 1/5) is applied to the gate terminal of the FET 120 according to the voltage dividing resistance ratio of R122 and R123. As a result, the FET 120 of the discharge circuit 109 is turned ON, and the charged smoothing capacitor 105 is discharged through the discharge resistor 118.

  Then, when the voltage of the smoothing capacitor 105 gradually decreases and the gate voltage of the FET 120 falls below the cut-off voltage, the FET 120 is turned off and the discharge by the discharge resistor 118 is finished. Specifically, for example, when the cut-off voltage is 4V, the voltage of the smoothing capacitor 105 is 20V (= 4V × 5).

  As described above, according to the present embodiment, discharging of the smoothing capacitor 105 via the discharge resistor 118 can be prohibited during the output operation of the inverter 106 of the grid interconnection inverter device 101. As a result, wasteful power consumption can be prevented, and a highly efficient grid-connected inverter device 101 can be realized.

  Further, according to the present embodiment, the control circuit 110 and the commercial AC 102 are electrically insulated by transmitting a signal for controlling ON / OFF of the FET 120 of the discharge circuit 109 via the prohibition signal photocoupler 124. it can. Similarly, control circuit 110, step-up converter switching element 114, switching elements Q101 to Q104, and disconnecting relay 108 can be electrically insulated and controlled by photocouplers PC101 to PC103. As a result, the control circuit 110 can realize a grid-connected inverter device that operates stably without being affected by the noise of the commercial AC 102 or the like.

  Further, according to the present embodiment, the voltage at which the smoothing capacitor is discharged via the discharge resistor 118 and the voltage at which the discharge LED 119 is extinguished can be arbitrarily set by the voltage dividing resistors R122 and R123.

  Alternatively, the discharge resistor 118 and the discharge LED 119 may be turned on and off by independent FETs, and the voltage for terminating the discharge and the voltage for turning off the discharge LED 119 may be set individually. Thereby, the grid connection inverter apparatus with a high design freedom is realizable.

(Embodiment 3)
Below, the grid connection inverter apparatus in Embodiment 3 of this invention is demonstrated using figures.

  FIG. 5 is a circuit block diagram of the grid-connected inverter device in the third embodiment of the present invention.

  The present embodiment is different from the first embodiment in that the boost converter, the inverter, and the control board are formed of different boards.

  That is, as shown in FIG. 5, the grid-connected inverter device of the present embodiment includes a boost converter 104, a smoothing capacitor 105, and a discharge circuit 109 on a first board 128, and an inverter 106, a filter 107, and a second board 129. The disconnecting relay 108 is configured by mounting a control circuit 110 on a control board 130.

  The first board 128 and the second board 129 are connected by a power harness 131, and the control board 130, the first board 128, and the second board 129 are connected by a signal harness 132. Note that the power harness 131 and the signal harness 132 are indicated by dotted lines in the drawing.

  According to the present embodiment, the discharge circuit 109 including the smoothing capacitor 105, the discharge resistor 118 serving as a discharge unit, and the discharge LED 119 serving as a notification unit is mounted on the same first substrate 128 as the boost converter 104.

  Therefore, for example, even when the power harness 131 is disconnected or not inserted into the connector of the power harness 131, the discharge of the smoothing capacitor charged by the discharge resistor 118 of the discharge circuit 109 and the discharge LED of the charging voltage of the smoothing capacitor Display can be performed reliably. As a result, a grid-connected inverter device with improved safety and workability during repair and replacement can be realized.

  In each of the above embodiments, the discharge circuit in which the discharge means using the discharge resistance and the notification means using the discharge LED are integrated has been described as an example. However, the present invention is not limited to this. For example, the discharging unit and the notification unit may be configured independently, and the same effect can be obtained. Furthermore, you may comprise a discharge circuit only with a discharge means. Thereby, the grid connection inverter apparatus which improved the safety | security and workability | operativity at the time of repair and replacement | exchange with the simplified structure is realizable.

  Moreover, in each said embodiment, although the brightness | luminance of discharge LED which is an alerting | reporting means demonstrated with the fall of a voltage, the example demonstrated, it is not restricted to this. For example, the number of lighting of the plurality of discharge LEDs may be changed according to the voltage level. Furthermore, you may change the color which discharge LED turns on with the fall of a voltage.

  The grid-connected inverter device according to the present invention can reduce the possibility of electric shock during repair / replacement by forcibly discharging the high voltage stored in the internal capacitor. Therefore, it is useful in technical fields such as gas engine power generators, solar power generators, and home-installed power generators such as electric water heaters that require local repair and replacement.

The circuit block diagram of the grid connection inverter apparatus in Embodiment 1 of this invention The block diagram explaining the discharge circuit connected to the grid connection inverter apparatus in Embodiment 1 of this invention The circuit block diagram of the grid connection inverter apparatus in Embodiment 2 of this invention Circuit block diagram of the discharge circuit in Embodiment 2 of the present invention The circuit block diagram of the grid connection inverter apparatus in Embodiment 3 of this invention Circuit block diagram of conventional grid-connected inverter device

DESCRIPTION OF SYMBOLS 101 Grid connection inverter apparatus 102 Commercial alternating current 104 Boost converter 105 Smoothing capacitor 106 Inverter 107 Filter 108 Disconnection relay (disconnection means)
109 Discharge Circuit 116 High Frequency Noise Reactor 117 Output Capacitor 118 Discharge Resistance (Discharge Means)
119 Discharge LED (notification means)
120 FET (Field Effect Transistor)
124 Photocoupler for prohibition signal 128 First substrate 129 Second substrate

Claims (7)

A boost converter that converts a DC input voltage to a predetermined high voltage, an inverter that converts a DC output to an AC output, and an output voltage of the boost converter provided between the output side of the boost converter and the input side of the inverter A smoothing capacitor that smoothes the AC output, a disconnection unit that disconnects the AC output of the inverter from a commercial AC, and a filter that includes a reactor and an output capacitor and is provided between the disconnection unit and the inverter. A grid-connected inverter device comprising discharge means for discharging the electric power stored in the smoothing capacitor. The grid interconnection inverter device according to claim 1, further comprising a prohibiting unit that prohibits the operation of the discharging unit during an output operation of the inverter. The grid interconnection inverter apparatus according to claim 2, wherein the prohibiting unit is insulated from the discharging unit. The grid interconnection inverter apparatus of any one of Claim 1 to 3 provided with the alerting | reporting means to alert | report when the voltage of the said smoothing capacitor is more than predetermined voltage. The grid-connected inverter device according to claim 4, wherein the notification means is a light emitting element whose luminance decreases as the voltage of the smoothing capacitor decreases. 6. The grid-connected inverter device according to claim 4, wherein the boost converter is provided on a first substrate, the inverter is provided on a second substrate, and the notification unit is provided on the first substrate. The grid interconnection inverter device according to any one of claims 1 to 6, wherein the boost converter is provided on a first substrate, the inverter is provided on a second substrate, and the discharging means is provided on the first substrate.

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