JP2006187196A - System interconnection inverter arrangement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress power consumption from a system side in a stand-by condition. <P>SOLUTION: When voltage Vp of a solar battery 1 exceeds stop voltage Vc, a control power source part 4 is started to supply electric power as a drive source to a control circuit 3. The control circuit 3, when the voltage Vp of the solar battery 1 is sufficient and the satisfaction of inverter start conditions, other than system conditions are confirmed, closes a system voltage detection relay 10, a commercial system 7 is connected to the control circuit 3 via an insulating transformer 5 for a monitor. The control circuit 3, when the system condition is confirmed as having satisfied the inverter start conditions, starts an inverter main circuit 2. Even if during the operation of the inverter main circuit 2, when the voltage Vp of the solar battery 1 becomes insufficient, the system voltage detection relay 10 is opened, to separate the commercial system 7 from the insulating transformer 5 for the monitor and a load connected to its secondary side, and the consumption of system electric power in these transformers and load is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a grid-connected inverter device that obtains power from a power supply source such as a DC power source or a generator, and more particularly to a power saving technique in a standby state.

  A solar power generation system converts DC power generated from a solar cell into AC power at a commercial frequency by a grid-connected inverter, supplies this AC power to a household load connected to the commercial system, and uses surplus power for commercial use. It is a system that flows backward to the grid side.

  FIG. 8 is a block diagram showing an electrical configuration of a grid-connected inverter device disclosed in Patent Document 1 as a conventional technique. In this case, the DC power of the solar cell 1 is converted into AC power by the interconnection inverter 2 ′, and this AC power is connected to the interconnection protection device 15 and the load 17 via the insulation transformer 12 and the switch 13. The interconnection protection device 15 is further connected to the commercial system 7. Power for driving is supplied from the commercial system 7 to the interconnection protection device 15 via the switch 14. Although not shown in the figure, the commercial power supply 7 supplies power for driving to the interconnection inverter 2 '. The switches 13 and 14 are controlled to open and close at a predetermined time set by the time setting means 16. Electric power is also supplied from the commercial system 7 to both the switches 13 and 14 and the time setting means 16. If the setting of the opening / closing time in the time setting means 16 is matched with the sunrise time or sunset time, and the opening / closing control of the switches 13 and 14 is performed at that time, in the time zone from the sunset time to the sunrise time, The power supply to the inverter 2 ', the insulation transformer 12, and the interconnection protection device 15 is cut off, and standby power is saved.

  In the case of the grid-connected inverter device configured as shown in FIG. 8, the power consumption supplied from the commercial system 7 in the standby state is large as described above. In the operating state, power loss in the isolation transformer 12 is also large. For these reasons, the system shown in FIG. 8 has hardly been adopted in recent grid-connected inverters. Instead, a transformerless system or a high-frequency insulation system has become the mainstream.

  The above is an introduction of the development of the technology, and is not about the prior art itself for the present invention. Hereinafter, the description of the prior art for the present invention proceeds. The grid-connected inverter device shown in FIG. 7 is a prior art for the present invention. The DC power of the solar cell 1 is converted into AC power having a commercial frequency by the grid interconnection inverter 8 and connected to the commercial system 7. The grid interconnection inverter 8 includes an inverter main circuit 2 that converts the DC power of the solar cell 1 into AC power having a commercial frequency, and a grid relay 6 that opens and closes the connection between the AC output terminal of the inverter main circuit 2 and the commercial system 7. A control circuit 3 that performs gate control of switching elements in the inverter main circuit 2, a control power supply unit 4 that receives DC power from the solar cell 1 and supplies constant-voltage power to the control circuit 3, and a commercial system 7. The monitor insulating transformer 5 is provided between the control circuit 3 and the control circuit 3. The control circuit 9 and the monitor insulating transformer 5 constitute a control unit 9.

  The control power supply unit 4 is activated by receiving DC power from the solar cell 1 and supplies driving power to the control circuit 3. In the control unit 9, the control circuit 3 inputs the voltage of the solar cell 1 to check whether or not there is a necessary voltage, and inputs the system voltage from the commercial system 7 via the monitor insulating transformer 5. After confirming that there is no abnormality in the system voltage and system frequency, the interconnection relay 6 is closed and the inverter main circuit 2 is started. The control circuit 3 performs synchronous control of the output current from the inverter main circuit 2 and the system voltage by controlling the gate of the switching element of the inverter main circuit 2. In addition to this control, the control circuit 3 performs automatic start / stop of the grid interconnection inverter 8 and various interconnection protection controls.

  Since it is necessary to detect the system voltage before closing the interconnection relay 6 in this way, the primary side of the monitoring insulation transformer 5 is connected to the commercial system 7 on the system side from the interconnection relay 6. There is.

  In the configuration of FIG. 7, the input power of the control power supply unit 4 is supplied from the solar cell 1, but there is a method of supplying from the commercial system 7.

  In the case of the grid-connected inverter device having the configuration of FIG. 7, the control power supply unit 4 that supplies power to the control circuit 3 for driving and controlling the inverter main circuit 2 receives DC power from the solar cell 1. Thus, the power from the commercial system 7 is not consumed in these portions, not limited to day and night.

Under the circumstances as described above, at present, the grid-connected inverter device of the system shown in FIG. 7 in which the grid-connected inverter 8 has a built-in grid protection function is the mainstream.
JP-A-6-197455

  In the conventional grid-connected inverter device shown in FIG. 7, for the reasons described above, the monitor insulating transformer 5 must be connected to the commercial system 7 on the grid side with respect to the grid relay 6. Therefore, in a standby state where power is not supplied from the solar cell 1 at night or in cloudy weather, a commercial system is caused by a load (not shown) connected to the secondary side of the monitor insulating transformer 5 or iron loss of the monitor insulating transformer 5. 7 is consumed, and this is the power consumption from the commercial system 7 of the grid-connected inverter device in the standby state.

  The present invention was created to solve the above-described problems, and aims to minimize power consumption from the system side in a standby state.

  The grid-connected inverter device according to the first aspect of the present invention which attempts to solve the above-described problems has the following configuration. That is, an inverter main circuit that converts DC power from a power supply source into AC power and connects to the power system, and a control that controls the inverter main circuit by inputting the state of the power supply source and the state of the power system A circuit, a control power supply unit that supplies driving power to the control circuit using the DC power as a driving source, and an opening / closing means interposed in a path that inputs the state of the power system to the control circuit, The power supply source is configured to close the switching means when a required condition such as having a voltage higher than a required level suitable for driving the inverter main circuit is satisfied, and to open the switching means when the condition is not satisfied. It is. This configuration has the following effects. In other words, due to circumstances such as nighttime or cloudy weather, the power supply source does not meet the required conditions such as not having a voltage higher than the required level suitable for driving the inverter main circuit. When opening / closing means is opened, power for monitoring is not supplied from the power system to the control circuit, so the monitoring system such as the monitoring transformer and the load connected to it consumes system power as standby power more than necessary. There is nothing to do.

  The grid-connected inverter device according to the second aspect of the present invention is configured as follows in the first aspect of the present invention. That is, when the voltage Vp of the power supply source is smaller than the closing reference value V1 of the opening / closing means set higher than the stop reference voltage Vs of the inverter main circuit and lower than the starting reference voltage Vo, the opening / closing means is opened. When the voltage Vp of the power supply source is equal to or higher than the closing reference value V1, the opening / closing means is closed. This configuration has the following effects. That is, even when the control circuit inputs the DC power of the power supply source as the drive source, the inverter main circuit cannot perform the interconnection operation when the voltage Vp of the power supply source is smaller than the closed reference value V1. In this situation, the switching means is opened, and the monitoring power is not supplied from the system to the control circuit. The time during which no power is consumed as standby power is lengthened, and further energy saving is achieved. If the closing reference value V1 of the opening / closing means is set equal to the starting reference voltage Vo of the inverter main circuit, the grid-connected inverter device starts up quickly.

  The grid-connected inverter device of the third invention according to the present invention is configured as follows in the first and second inventions of the present invention. That is, when the voltage Vp of the power supply source becomes equal to or lower than the open reference value V2 of the switching means set to be equal to or lower than the stop reference voltage Vs of the inverter main circuit, or the inverter main circuit shifts from the operating state to the stopped state. Sometimes it is configured to open the opening and closing means. This configuration has the following effects. That is, even when the control circuit is inputting the DC power of the power supply source as the drive source, if the voltage Vp of the power supply source is equal to or lower than the open reference value V2, the inverter main circuit cannot perform the interconnection operation. Although the inverter has stopped, the inverter main circuit may be stopped for some reason. In such a situation, the switching means is opened and monitoring power is not supplied from the system to the control circuit. Therefore, the time during which the system power is not consumed as standby power by the monitoring system such as the insulating transformer for monitoring and the load connected thereto is lengthened, thereby further saving energy. If the open reference value V2 of the opening / closing means is set equal to the stop reference voltage Vs of the inverter main circuit, the opening / closing means is opened simultaneously with the stop of the inverter main circuit, thereby further saving energy.

  In addition, since a drop is provided between the closing reference value V1 and the opening reference value V2 of the opening / closing means, chattering does not occur in the opening / closing operation of the opening / closing means, and the life of the opening / closing means is improved.

  A grid-connected inverter device according to a fourth aspect of the present invention is configured as follows in the first to third aspects of the present invention. That is, the control circuit is configured to close the opening / closing means when an inverter start condition other than the system state is satisfied, and to start the inverter main circuit when the system state satisfies the inverter start condition. . This configuration has the following effects. In other words, when the inverter start condition is not met and the standby state is set, the switching means is opened, and the system is also connected with the control circuit inputting the DC power of the power supply source as the drive source. Since no monitoring power is supplied from the control circuit to the control circuit, the time during which the system power is not consumed as standby power by the monitoring system such as the monitoring insulating transformer and the load connected thereto becomes longer, thereby further saving energy.

  The grid interconnection inverter device according to the fifth aspect of the present invention has the following configuration in the first to third aspects of the present invention. That is, the control circuit closes the opening / closing means when confirming that the inverter start condition other than the system state is satisfied, and further starts the inverter main circuit when the system state satisfies the inverter start condition, When the state does not satisfy the inverter start condition, the switching means is opened, and after a predetermined time interval, it is reconfirmed whether the inverter start condition other than the system state is satisfied. This configuration has the following effects. In other words, even if the switching means is once closed, if the system state does not satisfy the inverter start condition, the switching means is opened again. Therefore, the system power is set as standby power by the monitor system such as the monitor insulation transformer and the load connected thereto. The time when it is not consumed is further prolonged, and further energy saving is achieved. Furthermore, since an interval is set before reconfirmation, chattering does not occur in the opening / closing operation of the opening / closing means, and the life of the opening / closing means is improved.

  The grid-connected inverter device according to the sixth aspect of the present invention has the following configuration in the first aspect of the present invention. That is, the power supply source has a means for detecting the power Pp, and the power supply source Pp is set to be higher than the stop reference power Ps of the inverter main circuit and lower than the start reference power Po. The opening / closing means is opened when it is smaller than the closing reference value P1, and the opening / closing means is closed when the power Pp of the power supply source is equal to or greater than the closing reference value P1. According to this configuration, when the power supply source is a power detection type, by detecting the power Pp of the power supply source, when the power Pp is smaller than the closed reference value P1, the opening / closing means is opened and the commercial system Since the control circuit is disconnected, the standby power of the control circuit is not consumed.

  The grid-connected inverter device according to the seventh aspect of the present invention is configured as follows in the sixth aspect of the present invention. That is, the switching means is opened when the power (Pp) of the power supply source is equal to or less than the open reference value (P2) of the opening / closing means set to be equal to or less than the stop reference power (Ps) of the inverter main circuit. It is configured. According to this configuration, when the power supply source is a power detection type, the power Pp of the power supply source is detected, whereby the power Pp is set to be equal to or lower than the stop reference power Ps of the inverter main circuit. When the value is less than or equal to the value P2, since the opening / closing means is open and the commercial system is disconnected from the control circuit, standby power consumption of the control circuit is not performed.

In addition to the first to seventh inventions related to the present invention, other possible inventions will be described below.
Other grid-connected inverter devices according to the first aspect of the present invention are configured as follows in the first to fifth aspects of the present invention. That is, the opening / closing means is configured as a transfer contact system, one contact is connected to the system, and the other contact is connected to a relay test terminal. This configuration has the following effects. That is, the relay test terminal is a terminal for testing whether or not the inverter interconnection protection function is operating normally when installing the grid interconnection inverter device. The relay test terminal is not used in the operational state after the test is completed. By configuring the switching means to be a transfer contact system, both the monitoring system contact and the relay test terminal contact can be used together, and cost reduction and space saving can be achieved by reducing the number of parts. As a result, the opening / closing means is configured as a transfer contact method, and both the monitor system contact and the relay test terminal contact are used, so that cost reduction and space saving can be achieved by reducing the number of components.

  Further, the grid-connected inverter device of another invention 2 has the following configuration in the first to fifth inventions or the other invention 1 according to the present invention. That is, the power supply source requires fuel to generate power, and has means for detecting the remaining fuel amount Mf of the power supply source, and the remaining fuel amount Mf is lower than the remaining amount lower limit value M1. When it is small, the opening / closing means is opened, and when the remaining amount Mf is equal to or more than the remaining amount lower limit M1, the opening / closing means is closed. According to this configuration, when the remaining amount of the power supply source becomes smaller than the lower limit value, the opening / closing means is opened and the commercial system and the control circuit are disconnected, so that the standby power of the control circuit is not consumed. Thereby, when the remaining amount of the power supply source becomes smaller than the lower limit value, the switching means is opened and the commercial system and the control circuit are disconnected, so that the standby power of the control circuit is not consumed.

  Further, the grid-connected inverter device of another invention 3 has the following configuration in the first to seventh inventions or the other invention 1 or 2 according to the present invention. That is, it has an open / close mode switching means for switching the open / close mode of the open / close means to manual open / close or automatic open / close. According to this configuration, since the opening / closing control of the opening / closing means can be separated from the command of the control circuit by the opening / closing mode switching means, the opening / closing means can be switched manually. As a result, the opening / closing means can be manually opened / closed. For example, when performing maintenance and inspection of the apparatus, the monitor system such as the insulation transformer for the monitor and the load connected thereto are completely inspected in a state of being completely disconnected from the commercial system. be able to.

  The above-described constituent elements of the present invention can be interpreted as follows. The “system” is usually a commercial system, but it is not necessary to limit to the commercial system. The “state of the power supply source” is generally the electric power or voltage or current generated in the power supply source or other electrical quantity or a physical quantity related thereto. The same applies to the “system state”. The “opening / closing means” may be any device that switches between a state of transmitting electricity and a state of blocking, such as a mechanical, electrical or electronic relay, switch, switch. The symbols Vp, Vo, Vs, V1, V2, Vc, Mf, M1, Pp, Po, Ps, P1, and P2 are the same as those in the embodiments described later. It is not necessary to be bound by the specific numerical values shown, and can be interpreted within a reasonable range. Further, the term “characteristic” in the description of the claims is merely for convenience of explanation, and the actual configuration of the grid-connected inverter device targeted by the present invention has a special configuration. It should not be interpreted only as meaning that it appears prominently. It should be noted that the terminology is used for convenience of explanation in comparison with the prior art.

  According to the first aspect of the invention relating to the grid-connected inverter device, when an opening / closing means is inserted in the path for monitoring and inputting the status of the grid to the control circuit, and the status of the power supply source does not satisfy the required condition Since the opening / closing means is configured to open, the state of the power supply source is insufficient to drive the inverter main circuit due to circumstances such as nighttime or cloudy weather, and the standby state is entered. When it is, the monitor system and the load connected thereto do not consume more system power than necessary, and energy can be saved.

  According to the second aspect of the present invention, as long as the voltage Vp of the power supply source does not reach the closing reference value V1 of the opening / closing means, the opening / closing means is opened, and monitoring power is supplied from the system to the control circuit. Therefore, even when the control circuit inputs the DC power of the power supply source as a drive source, the monitor system such as the monitor insulation transformer and the load connected to it will not spend system power as standby power for a long time. Further energy saving can be achieved.

  According to the third invention of the present invention, when the voltage Vp of the power supply source is less than or equal to the open reference value V2, and when the inverter main circuit is stopped for some reason, the opening / closing means is opened, Since power for monitoring is not supplied from the system to the control circuit, even when the control circuit is inputting the DC power of the power supply source as the drive source, the monitor system such as the monitor insulation transformer and The time during which the system power is not consumed as standby power by the load becomes longer, and further energy saving can be achieved.

  According to the fourth aspect of the present invention, when the inverter start condition is not satisfied and the apparatus is in the standby state, the switching means is opened and the monitoring power is not supplied from the system to the control circuit. Therefore, even when the control circuit inputs the DC power of the power supply source as the drive source, the time during which the system power is not consumed as standby power by the monitor system and the load connected thereto becomes longer, and further energy saving is achieved. Can do.

  According to the fifth invention of the present invention, even if the switching means is once closed, if the system state does not satisfy the inverter starting condition, the switching means is opened again. The time during which no standby power is consumed is further increased, and further energy saving can be achieved. Furthermore, since an interval is set before reconfirmation, chattering does not occur in the opening / closing operation of the opening / closing means, and the life of the opening / closing means can be improved.

  According to the sixth aspect of the present invention, when the power supply source is a power detection type, the opening / closing means is opened unless the power Pp reaches the closed reference value P1 by detecting the power Pp of the power supply source. Therefore, since the commercial system and the control circuit are separated, the standby power of the control circuit is not consumed.

  According to the seventh aspect of the present invention, when the power supply source is a power detection type, the power Pp is set to be equal to or lower than the stop reference power Ps of the inverter main circuit by detecting the power Pp of the power supply source. When the open / close means is below the open reference value P2, the open / close means is open and the commercial system is disconnected from the control circuit, so that no standby power is consumed by the control circuit.

Embodiments of a grid-connected inverter device according to the present invention will be described below in detail with reference to the drawings.

[Embodiment 1]
FIG. 1 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the first embodiment. As shown in FIG. 1, the grid interconnection inverter 8 includes an inverter main circuit 2, a control circuit 3, a control power supply unit 4, a grid relay 6, a monitor insulation transformer 5, and a newly added grid voltage detection relay. 10. A control unit 9 is constituted by the control circuit 3 and the monitor insulating transformer 5. The output terminal of the solar cell 1 is connected to the input terminals of the inverter main circuit 2, the control circuit 3, and the control power supply unit 4 in the grid interconnection inverter 8. The control power supply unit 4 receives DC power from the solar cell 1 to generate a constant voltage, and supplies the constant voltage to the control circuit 3 as a drive source. A load (not shown) is connected to the secondary side of the monitor insulating transformer 5.

  The control circuit 3 is configured to be controlled by a microcomputer, a DSP (digital signal processor), or the like. Here, the microcomputer is used. When the control circuit 3 receives a constant voltage as a drive source from the control power supply unit 4, the control circuit 3 starts the microcomputer. The control circuit 3 determines the voltage Vp of the solar cell 1. In principle, the control circuit 3 is configured to close the system voltage detection relay 10 and start the inverter main circuit 2 when the voltage Vp of the solar cell 1 is equal to or higher than the closed reference value V1 of the system voltage detection relay 10. ing. The control circuit 3 is also configured to stop the inverter main circuit 2 and open the system voltage detection relay 10 in principle when the voltage Vp of the solar cell 1 is equal to or lower than the stop reference voltage Vs of the inverter main circuit 2. ing. This point will be described in detail later. The control circuit 3 also performs various interconnection protection controls for the grid interconnection inverter 8. The control circuit 3 drives the inverter main circuit 2 by performing gate control of the switching elements in the inverter main circuit 2.

  The inverter main circuit 2 converts the DC power from the solar cell 1 into AC power having a commercial frequency. The output terminal of the inverter main circuit 2 is connected to the commercial system 7 via the interconnection relay 6. The middle of the connection line between the commercial system 7 and the interconnection relay 6 and the primary side of the monitoring insulating transformer 5 in the control unit 9 are connected via a newly added system voltage detection relay 10. The secondary side of the monitor insulating transformer 5 is connected to the control circuit 3 and connected to a load (not shown).

  The interconnection relay 6 is controlled to open and close based on a control signal from the control circuit 3. The system voltage detection relay 10 is controlled to open and close based on a control signal from the control circuit 3.

  The system voltage of the commercial system 7 is input to the control circuit 3 via the system voltage detection relay 10 and the monitor isolation transformer 5, and the control circuit 3 calculates the output current of the inverter main circuit 2 and the system voltage based on the system voltage. It is configured to perform synchronous control or to perform interconnection protection control.

  Next, the operation of the grid-connected inverter device of the first embodiment configured as described above will be described.

  In the normal state, the inverter main circuit 2 is in a stopped state, and the system voltage detection relay 10 is normally open. When the output voltage Vp of the solar cell 1 reaches a predetermined value (exceeds the stop voltage Vc), the control power supply unit 4 is activated and starts supplying a constant voltage to the control circuit 3. The microcomputer in the control circuit 3 starts operation upon receiving a constant voltage power supply from the control power supply unit 4, and when the inverter main circuit 2 is activated outside the system that there is sufficient power in the solar cell 1. The system voltage detection relay 10 is closed by confirming that there is no abnormality, that is, that the inverter starting conditions other than the system state are satisfied and energizing the relay coil of the system voltage detection relay 10. Then, by closing the system voltage detection relay 10, the system voltage is input from the commercial system 7 side, and it is confirmed that there is no abnormality in the system voltage and system frequency, that is, the system state satisfies the inverter starting condition. Then, the inverter main circuit 2 is started.

  Next, details of the above operation will be described with reference to the flowchart of FIG. Before the description, the starting reference voltage Vo and the stopping reference voltage Vs of the inverter main circuit 2, the closing reference value V1 and the opening reference value V2 of the system voltage detection relay 10, and the stopping voltage Vc of the control power supply unit 4 are large and small. Describe the relationship. The start reference voltage Vo is higher than the stop reference voltage Vs. The closed reference value V1 of the system voltage detection relay 10 is equal to or lower than the starting reference voltage Vo of the inverter main circuit 2, but here it is assumed that V1 = Vo. Further, the open reference value V2 of the system voltage detection relay 10 is equal to or lower than the stop reference voltage Vs of the inverter main circuit 2 and higher than the stop voltage Vc of the control power supply unit 4. Here, V2 = Vs. Examples of numerical values include V1 = Vo = 160V, V2 = Vs = 130V, and Vc = 80V. However, it is needless to say that such numerical values are merely examples, and may be appropriately changed according to specifications.

  A CPU (central processing unit) in the microcomputer determines whether or not the voltage Vp of the solar cell 1 read in step S101 is equal to or higher than the detection relay closing reference value V1. When Vp <V1, the process proceeds to step S201. When Vp ≧ V1, the process proceeds to step S102, and it is determined whether or not there is any abnormality in the inverter activation conditions other than the system state. For example, in the grid interconnection inverter 8, it is determined whether there is an abnormality in the internal temperature or whether there is a failure such as a fuse blown. If an abnormality is recognized in the determination, the process proceeds to step S201. If there is no abnormality, the process proceeds to step S103, and the control voltage is supplied from the control circuit 3 to the system voltage detection relay 10, thereby providing a system voltage detection relay. 10 is closed. As a result, the system voltage of the commercial system 7 is brought into the control circuit 3 via the system voltage detection relay 10 and the monitor insulating transformer 5.

  Next, the process proceeds to step S104 to read the captured system voltage waveform, and determine whether there is no abnormality in the effective voltage or frequency, that is, whether the system state satisfies the inverter start condition. If there is an abnormality, the process proceeds to step S201. If there is no abnormality, the process proceeds to step S105, where the control circuit 3 applies a closing control signal to the interconnection relay 6 to close the interconnection relay 6. Next, the process proceeds to step S106 to start the inverter main circuit 2.

  When the determination in step S102 or the determination in step S104 is negative, the process proceeds to step S201. This step S201 is a step to be processed immediately after the inverter main circuit 2 is stopped. That is, when the voltage Vp of the solar cell 1 becomes equal to or lower than the stop reference voltage Vs of the inverter main circuit 2, the inverter main circuit 2 is stopped and the interconnection relay 6 is opened, but immediately thereafter, the process proceeds to step S201. ing.

  In step S201, it is determined whether or not the read voltage Vp of the solar cell 1 is equal to or lower than the detection relay open reference value V2. When Vp> V2, the process proceeds to step S101, but when Vp ≦ V2, the process proceeds to step S202 to open the system voltage detection relay 10 by giving an open control signal to the system voltage detection relay 10 from the control circuit 3. . When V2 = Vs is set and the voltage Vp of the solar cell 1 is equal to or lower than the stop reference voltage Vs, the voltage Vp is also equal to or lower than the detection relay open reference value V2, and the control circuit 3 stops the inverter main circuit 2 At the same time, the system voltage detection relay 10 is also opened, and system power consumption at the load connected to the monitoring insulating transformer 5 and its secondary side is minimized.

  It should be noted that when the inverter main circuit 2 is stopped and the interconnection relay 6 is opened, it is also possible to proceed to step S202 immediately without making the determination of step S201 and to always open the system voltage detection relay 10. .

  According to the above configuration, the voltage Vp of the solar cell 1 reaches the detection relay closing reference value V1 even when the control circuit 3 inputs the DC power of the solar cell 1 as a drive source via the control power supply unit 4. As long as the inverter main circuit 2 does not perform the interconnection operation, the inverter main circuit 2 is stopped, but in such a situation, the grid voltage detection relay 10 is opened, and the power for monitoring from the commercial grid 7 to the control circuit 3 is reduced. Since the supply is not performed, the time during which the system power is not consumed as standby power in the monitor insulating transformer 5 and the load connected to the secondary side of the monitoring transformer 5 is increased, thereby saving energy.

  Similarly to the above, the voltage Vp of the solar cell 1 is not more than the detection relay open reference value V2 even when the control circuit 3 inputs the DC power of the solar cell 1 as a drive source via the control power supply unit 4. In this case, the inverter main circuit 2 is stopped without performing the interconnection operation, and the inverter main circuit 2 may be stopped due to some factors. In such a situation, the system voltage detection relay 10 is opened, the time during which the system power is not consumed as standby power in the load connected to the monitoring insulating transformer 5 and the secondary side thereof becomes longer, and energy saving is achieved.

  Further, if V1 = Vo is set, the voltage Vp of the solar cell 1 reaches the detection relay closing reference value V1 or more and the operation of closing the system voltage detection relay 10 and the inverter main circuit 2 are set as long as there is no abnormality. Start-up can be performed simultaneously, and the inverter main circuit 2 rises to a stable state quickly. If V2 = Vs is set, the inverter main circuit 2 can be stopped and the system voltage detection relay 10 can be opened at the same time, and the monitoring insulating transformer 5 and the load connected to the secondary side thereof are connected. It is possible to minimize the power consumption of the system.

  However, the present invention need not be limited to this, and Vo> V1 may be set, or Vs> V2 may be set.

  Further, since a drop is provided between the detection relay closing reference value V1 and the detection relay opening reference value V2, chattering does not occur in the open / close operation of the system voltage detection relay 10, and the life of the system voltage detection relay 10 is improved. To do.

  Moreover, it can also be set as a structure shown in FIG. 13 so that the system voltage detection relay 10 can be opened and closed manually. In the inverter device shown in FIG. 1, an open / close mode switching means 21 for newly switching the open / close mode of the system voltage detection relay 10 to automatic open / close or manual open / close is provided. Normally, the open / close mode switching means 21 sets the open / close mode of the system voltage detection relay 10 to the automatic open / close mode, and the open / close mode of the system voltage detection relay 10 is controlled according to a command from the control circuit. For example, when it is necessary to forcibly disconnect from the commercial system for maintenance and inspection of the inverter device, the system voltage detection is manually performed by switching the open / close mode of the system voltage detection relay 10 to the manual open / close mode by the open / close mode switching means 21. The relay 10 can be opened and closed.

[Embodiment 2]
The configuration of the grid-connected inverter device of the second embodiment is the same as that of FIG. 1 in the first embodiment, and the sequence of the control circuit 3 by the microcomputer is changed.

  The sequence is shown in the flowchart of FIG. The sequence of FIG. 3 differs from the sequence of FIG. 2 in the following points. That is, it proceeds to step S104, reads the waveform of the system voltage taken in, determines whether there is any abnormality in the effective voltage or frequency, that is, confirms that the system state satisfies the inverter start condition, If so, the process proceeds to step S107, and the system voltage detection relay 10 closed in the previous step S103 is opened again. Then, after proceeding to step S108 and performing standby (idling) for a predetermined time, the process returns to step S101.

  The significance of the sequence of FIG. 3 will be described. In the case of the sequence of FIG. 2, even if the system voltage or system frequency is abnormal in step S104, if the voltage Vp of the solar cell 1 does not become the detection relay open reference value V2 or less, the system voltage detection relay 10 Do not open. Therefore, even when there is an abnormality, the system voltage is supplied to the monitor insulation transformer 5 via the system voltage detection relay 10, and the power consumption of the system power at the load connected to the monitor insulation transformer 5 and its secondary side is consumed. Will continue.

  On the other hand, according to the sequence of FIG. 3, when the inverter starting condition other than the system state is satisfied, the system voltage detection relay 10 is once closed and the monitoring power is taken into the control circuit 3 from the commercial system 7. The system is determined. As a result, when it is determined that the system voltage or system frequency is abnormal and the system state does not satisfy the inverter starting condition, the once-closed system voltage detection relay 10 is immediately opened again. As a result, the time during which the system power is not consumed as standby power in the monitor isolation transformer 5 and the load connected to the secondary side of the monitor transformer 5 becomes longer, thereby further saving energy.

  Since an interval of a predetermined time is set before reconfirmation in step S101 due to idling in step S108, chattering does not occur in the open / close operation of the system voltage detection relay 10, and the life of the system voltage detection relay 10 is improved.

[Embodiment 3]
In the third embodiment, the position of the system voltage detection relay 10 is changed. FIG. 4 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the third embodiment. The same reference numerals as in FIG. 1 for the first embodiment also indicate the same components in FIG. 4 for the third embodiment. Briefly, 1 is a solar cell, 2 is an inverter main circuit, 3 is a control circuit, 4 is a control power supply unit, 5 is an insulating transformer for monitoring, 6 is an interconnection relay, 7 is a commercial system, 8 is a system interconnection inverter, 9 is a control unit, and their coupling relationship is also particularly Since it is as described above unless otherwise stated, detailed description is omitted here. Further, items described in the first embodiment and not described in the present embodiment are also applicable to the present embodiment as they are, and detailed description thereof is omitted. The configuration of the third embodiment is different from that of the first embodiment as follows.

  That is, the system voltage detection relay 10 is inserted in a common line portion between the connection line between the commercial system 7 and the interconnection relay 6 and the connection line between the commercial system 7 and the primary side of the monitoring insulating transformer 5.

  In the third embodiment, the microcomputer sequence in the control circuit 3 can be used as it is. Further, the sequence of FIG. 3 may be used as it is.

  The operation of the grid-connected inverter device of the third embodiment is the same as that of the first embodiment when the sequence of FIG. 2 is used, and the second embodiment when the sequence of FIG. 3 is used. Since this is the same as the case of, the description is omitted. The same effects are obtained.

[Embodiment 4]
FIG. 5 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the fourth embodiment. In the fourth embodiment, in comparison with the first embodiment in FIG. 1, the control power source unit 4 is used instead of the control circuit 3 as a source for controlling the system voltage detection relay 10. The same reference numerals as those in FIG. 1 for the first embodiment also indicate the same components in FIG. 5 for the fourth embodiment, and as described above, unless the relationship between them is particularly specified. Therefore, detailed description is omitted here. Further, items described in the first embodiment and not described in the present embodiment are also applicable to the present embodiment as they are, and detailed description thereof is omitted. The configuration of the fourth embodiment is different from that of the first embodiment as follows.

  That is, the control power supply unit 4 is configured to send a control signal for opening and closing the system voltage detection relay 10 to the system voltage detection relay 10. The system voltage detection relay 10 is interposed between the commercial system 7 and the primary side of the monitoring insulating transformer 5. When the solar battery 1 reaches a predetermined voltage or higher, the control power supply unit 4 supplies the control circuit 3 with DC power of a constant voltage as a drive source. At this time, the control power supply unit 4 controls the relay coil in the system voltage detection relay 10 to be closed. A signal is given and the system voltage detection relay 10 is closed. Further, when the voltage of the solar cell 1 becomes lower than the predetermined voltage, the supply of DC power to the control circuit 3 is stopped. At this time, the system voltage detection relay 10 is opened at the same time.

  According to the fourth embodiment, it is not necessary to control the opening / closing of the system voltage detection relay 10 under various conditions by the sequence processing in the microcomputer as in the first to third embodiments. Since the operation is extremely simple, the configuration can be simplified.

  Since other operations are the same as those in the first embodiment, description thereof is omitted. The same effects are obtained.

[Embodiment 5]
FIG. 6 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the fifth embodiment. In the fifth embodiment, the system voltage detection relay 10 is changed to the transfer contact method (two-contact method) in comparison with the first embodiment shown in FIG. The same reference numerals as those in FIG. 1 for the first embodiment also indicate the same components in FIG. 6 for the fifth embodiment, and their connection relations are as described above unless otherwise specified. Therefore, detailed description is omitted here. Further, items described in the first embodiment and not described in the present embodiment are also applicable to the present embodiment as they are, and detailed description thereof is omitted. The configuration of the fifth embodiment is different from that of the first embodiment as follows.

  That is, a transfer contact type (two-contact type) is used as the system voltage detection relay 10 interposed between the commercial system 7 and the primary side of the monitor insulating transformer 5. The c contact (common terminal) is connected to the primary side of the insulating transformer 5 for monitoring, the a contact is connected to the commercial system 7 side, and the b contact is connected to the relay test terminal 11 side.

  The relay test terminal 11 is a terminal for testing whether or not the inverter interconnection protection function is operating normally when installing the grid interconnection inverter device. As the interconnection protection function, for example, there is a function that opens the interconnection relay 6 when a system overvoltage, a system voltage shortage, a system frequency increase or decrease occurs, and the like. In the test, a simulated voltage is applied to the relay test terminal 11 from the control circuit 3 via the monitoring insulation transformer 5 and the b contact of the transfer contact type system voltage detection relay 10.

  In the actual operation state after the grid-connected inverter device is installed and the test is completed, a simulated voltage is not applied from the control circuit 3 to the relay test terminal 11. Regarding the operation of the grid-connected inverter device in the actual operation state, when the control circuit 3 gives a closed control signal to the grid voltage detection relay 10, the grid voltage detection relay 10 is connected to the a contact side, The commercial system 7 is connected to the primary side of the monitoring insulating transformer 5 via the system voltage detection relay 10. Further, when the control circuit 3 gives an open control signal to the system voltage detection relay 10, the system voltage detection relay 10 is connected to the b contact side, but no special operation occurs.

  In the fifth embodiment, the control circuit 3 can use the microcomputer sequence as it is as the microcomputer sequence. Further, the sequence of FIG. 3 may be used as it is. The operation of the grid interconnection inverter device of the fifth embodiment is the same as that of the first embodiment when the sequence of FIG. 2 is used, and the second embodiment when the sequence of FIG. 3 is used. Since this is the same as the case of, the description is omitted. The same effects are obtained.

  Furthermore, in the fifth embodiment, by configuring the system voltage detection relay 10 to be a transfer contact system, switch means for switching the connection between the commercial system 7 and the monitor insulating transformer 5, and a relay test terminal 11 is also used as a switch means when operating 11, the cost can be reduced and the space can be saved by reducing the number of parts.

[Embodiment 6]
FIG. 9 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the sixth embodiment. In the sixth embodiment, the remaining amount of fuel detection means 19 is newly provided by replacing the solar cell 1 with the fuel cell 18 in comparison with the first embodiment of FIG. The same reference numerals as those in FIG. 1 for the first embodiment also indicate the same components in FIG. 9 for the sixth embodiment, and their connection relationships are as described above unless otherwise specified. Therefore, detailed description is omitted here. Further, items described in the first embodiment and not described in the present embodiment are also applicable to the present embodiment as they are, and detailed description thereof is omitted. The configuration of the sixth embodiment is different from that of the first embodiment as follows.

  That is, the DC power of the fuel cell 18 is converted into AC power having a commercial frequency by the grid interconnection inverter 8 and connected to the commercial grid 7. The remaining fuel amount detection means 19 detects the remaining fuel amount of the fuel cell 18 and sends the detected value to the control circuit 3. The control circuit 3 inputs the voltage of the fuel cell 18 so that the inverter has sufficient power for the grid interconnection operation, the fuel remaining amount detection value is equal to or greater than a predetermined value, and the system In addition to this, it is confirmed that there is no abnormality in starting the inverter, and the system voltage detection relay 10 is closed.

  For example, the control circuit 3 controls the opening and closing of the system voltage detection relay 10 according to the sequence shown in the flowchart of FIG. The control circuit receives power from the control power supply 4 and the microcomputer starts to start. At this time, in the initial state, the system voltage detection relay 10 is in an opened state, and the inverter is in a stopped state. When the microcomputer is activated, it first executes step S301, reads the fuel remaining amount value Mf of the fuel cell, and compares it with the fuel lower limit value M1. If Mf <M1, the process proceeds to step S402. If Mf ≧ M1, the process proceeds to step S302, where the fuel cell voltage Vp is read and compared with the system voltage detection relay closing reference value V1. Here, the setting of the closed reference value V1 is the same as in the first embodiment. If Vp <V1, the process proceeds to step S401. If Vp ≧ V1, the process proceeds to step S303, and inverter activation conditions other than system conditions are confirmed. If there is an abnormality, the process proceeds to step S401. If there is no abnormality, the system voltage detection relay 10 is closed in step S304, and the process proceeds to step S305. In step S305, the system voltage waveform is read via the system voltage detection relay 10, and it is confirmed whether the effective voltage and frequency are within the normal range. If there is an abnormality, the process proceeds to step S401. Then, the interconnection relay 6 is closed and the inverter is started in step S307.

  Next, when the inverter is stopped, step S401 is executed. In step S401, the fuel cell voltage Vp is read and compared with the system voltage detection relay open reference value V2. Here, the setting of the open reference value V2 is the same as in the first embodiment. If Vp ≦ V2, the process proceeds to step S402, a signal for opening the system voltage detection relay 10 is output, and the process returns to step S401. On the other hand, if Vp> V2, the process proceeds to step S301. Also, as in the first embodiment, it is a good method to always open the system voltage detection relay 10 when the inverter shifts from the operating state to the stopped state.

  Similarly to the sequence of FIG. 3 of the first embodiment, when an abnormality is detected in the system state in step S305 of the flowchart of FIG. 10, the system voltage detection relay 10 is immediately opened and a predetermined time is waited to return to step S301. , The power consumption from the grid can be further reduced.

  Furthermore, as in FIG. 4 of the third embodiment, the following changes can be added to the configuration of FIG. 9 of the sixth embodiment. That is, the system voltage detection relay 10 is installed between the interconnection relay 6 and the commercial system 7, and the system line between the interconnection relay 6 and the system voltage detection relay 10 is connected to the transformer 5 in the control unit 9. It is also possible.

  Further, as in FIG. 5 of the fourth embodiment, the following changes can be added to the configuration of FIG. 9 of the sixth embodiment. In other words, the control power supply 4 opens and closes the system voltage detection relay 10. The control power supply 4 starts supplying power to the control circuit 3 when the fuel cell 18 has a predetermined voltage or higher. At this time, a voltage is also applied to the relay coil of the system voltage detection relay 10, and the system voltage detection relay 10 is turned on. close. Further, when the voltage of the fuel cell 18 becomes equal to or lower than a predetermined voltage, power supply to the control circuit 3 and the system voltage detection relay 10 is stopped.

  In addition, as in FIG. 6 of the fifth embodiment, the following changes can be added to the configuration of FIG. 9 of the sixth embodiment. That is, the system voltage detection relay 10 is a two-contact (a, b) changeover switch, and the contact a is connected to the commercial system 7 and the contact b is connected to the relay test terminal 11. In the description of the sixth embodiment, when the system voltage detection relay 10 is closed, it is connected to the contact a, and when the system voltage detection relay 10 is opened, it is connected to the contact b.

[Embodiment 7]
FIG. 11 is a block circuit diagram showing an electrical configuration of the grid-connected inverter device of the seventh embodiment. In the seventh embodiment, power detection means 20 is provided between the solar cell 1 and the inverter circuit 2 in comparison with the first embodiment of FIG. The same reference numerals as those in FIG. 1 for the first embodiment indicate the same constituent elements in FIG. 11 for the seventh embodiment, and their connection relations are as described above unless otherwise specified. Therefore, detailed description is omitted here. Further, items described in the first embodiment and not described in the present embodiment are also applicable to the present embodiment as they are, and detailed description thereof is omitted. The configuration of the seventh embodiment is different from that of the first embodiment as follows.

  That is, the control circuit 3 detects the generated power of the solar cell 1 through the power detection means 20, and the solar cell 1 has sufficient power for the grid interconnection operation, and the inverter other than the grid After confirming that there is no abnormality in starting the system, the system voltage detection relay 10 is closed. For example, as a method of power detection during a period when the inverter is not performing grid connection operation, a resistor is connected to the solar cell 1 only during the period, a current value flowing through the resistor is detected by a current sensor, and a solar cell output There is a method of calculating the solar cell power by taking the product with the voltage. During the period in which the inverter is connected to the grid, the resistance power detection leads to a decrease in the inverter efficiency. Therefore, the current value flowing from the solar cell 1 to the inverter circuit 2 is detected by disconnecting the resistance, and the power is similarly supplied. calculate.

  For example, the control circuit 3 controls the opening and closing of the system voltage detection relay 10 according to the sequence shown in the flowchart of FIG. This is obtained by changing only the determination conditions of step S101 and step S201 in the flowchart of FIG. 2R> 2 in the first embodiment. In the initial state, the system voltage detection relay 10 is open, and the inverter is in a stopped state. When the microcomputer is activated by receiving power supply from the control power supply 4, the control circuit 3 first executes step S501, reads the power Pp of the solar cell, and compares it with the system voltage detection relay closed reference value P1. The closed reference value P1 is set to a value that is equal to or less than the start reference power Po of the inverter and greater than the stop reference power Ps. Here, P1 = Po. As a result of the comparison, if the solar cell power Pp is low, the process proceeds to step S502, and the subsequent processing is the same as in the first embodiment. When the inverter is stopped, step S502 is executed. In step S502, the solar cell power Pp is compared with the system voltage detection relay open reference value P2. The open reference value P2 is set to a value that is equal to or less than the inverter stop reference power Ps and higher than the stop power Pc of the control power supply 4. However, in order to reduce power consumption from the system as much as possible, set P2 = Ps. The system voltage detection relay 10 is opened simultaneously with the inverter stop. The processes after step S502 are the same as those in the first embodiment.

Although several embodiments have been described above, the present invention may include those configured as follows.
(1) As a modification of the third embodiment (FIG. 4), a grid-connected inverter device having a circuit configuration in which the grid relay 6 is omitted may be used.
(2) As a modification of the fourth embodiment (FIG. 5), the arrangement position of the system voltage detection relay 10 may be the same as that of the third embodiment (FIG. 4).
(3) As a modification of the fifth embodiment (FIG. 6), the arrangement position of the system voltage detection relay 10 is the same as that of the third embodiment (FIG. 4). It is good also as a structure which inserted the system voltage detection relay 10 of the transfer contact system in the common line part of the connection line of this, and the connection line of the commercial system 7 and the primary side of the insulation transformer 5 for a monitor.
(4) Following the system of the fourth embodiment (FIG. 5), the system voltage detection relay is connected from the control power supply unit 4 regardless of the insertion position of the system voltage detection relay 10 of the transfer contact system. 10 may be configured to be controlled to open and close.
(5) Other arbitrary matters that are not directly related to the gist of the present invention may be any known ones, and other than the publicly known ones may be applied without departing from the gist of the present invention. Needless to say, this is applicable.

  The above (1) to (5) are items independent of each other, and any number of these items may be appropriately combined.

  In the specification (especially, the detailed description of the invention and the claims) or the drawings relating to the present invention, any matter described (including any element or any combination or combination of elements) Reserve the possibility of omission. Furthermore, there is a possibility of addition to the scope of claims for any matter not described in the scope of claims but described in the detailed description of the invention or in the drawings, and possibility of change of explanation accompanying the addition. Reserve.

It is a block circuit diagram which shows the electric constitution of the grid connection inverter apparatus of Embodiment 1 of this invention. 4 is a flowchart for explaining the operation of the grid-connected inverter device of the first embodiment. 7 is a flowchart for explaining the operation of the grid-connected inverter device of the second embodiment. FIG. 6 is a block circuit diagram illustrating an electrical configuration of a grid-connected inverter device according to a third embodiment. FIG. 6 is a block circuit diagram showing an electrical configuration of a grid-connected inverter device of a fourth embodiment. FIG. 10 is a block circuit diagram showing an electrical configuration of a grid-connected inverter device of a fifth embodiment. It is a block circuit diagram which shows the electric constitution of the grid connection inverter apparatus of a prior art. It is a block diagram which shows the electric constitution of the grid connection inverter apparatus of the old type. FIG. 10 is a block circuit diagram showing an electrical configuration of a grid-connected inverter device of a sixth embodiment. 10 is a flowchart for explaining the operation of the grid-connected inverter device of the sixth embodiment. FIG. 10 is a block circuit diagram showing an electrical configuration of a grid-connected inverter device of a seventh embodiment. 18 is a flowchart for explaining the operation of the grid-connected inverter device of the seventh embodiment. It is a block circuit diagram which shows the electric constitution of another grid connection inverter apparatus of Embodiment 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Solar cell, 2 inverter main circuit, 3 control circuit, 4 control power supply part, 5 monitor insulation transformer, 6 connection relay, 7 commercial system, 8 system connection inverter, 9 control part, 10 system voltage detection relay, 11 Relay test terminal, 18 fuel cell, 19 fuel remaining amount detecting means, 20 power detecting means, 21 open / close mode switching means.

Claims (7)

An inverter main circuit for converting DC power from the power supply source into AC power and connecting it to the power system;
A control circuit for controlling the inverter main circuit by inputting the state of the power supply source and the state of the power system;
A control power supply for supplying driving power to the control circuit using the DC power as a driving source;
Opening and closing means inserted in a path for inputting the state of the power system to the control circuit,
The grid-connected inverter device is configured to close the opening / closing means when the state of the power supply source satisfies a required condition, and to open the opening / closing means when the state is not satisfied.   When the voltage (Vp) of the power supply source is smaller than the closing reference value (V1) of the switching means set higher than the stop reference voltage (Vs) of the inverter main circuit and lower than the starting reference voltage (Vo), The opening / closing means is opened, and the opening / closing means is closed when the voltage (Vp) of the power supply source is equal to or higher than the closing reference value (V1). Grid-connected inverter device.   When the voltage (Vp) of the power supply source is lower than the open reference value (V2) of the opening / closing means set to be lower than the stop reference voltage (Vs) of the inverter main circuit, or the inverter main circuit is stopped from the operating state The system interconnection inverter device according to claim 1 or 2, wherein the switching means is configured to open when shifting to a state.   The control circuit is configured to close the opening / closing means when an inverter start condition other than the system state is satisfied, and to start the inverter main circuit when the system state satisfies the inverter start condition. The grid interconnection inverter device according to any one of claims 1 to 3, wherein the grid interconnection inverter device is provided. The control circuit closes the opening / closing means when confirming that the inverter start condition other than the system state is satisfied, and further starts the inverter main circuit when the system state satisfies the inverter start condition, and the system state is When the inverter start condition is not satisfied, the switching means is opened, and after a predetermined time interval, it is configured to reconfirm whether the inverter start condition other than the system state is satisfied. The grid interconnection inverter device according to any one of claims 1 to 3.   Means for detecting the power (Pp) of the power supply source, wherein the power (Pp) of the power supply source is set to be higher than the stop reference power (Ps) of the inverter main circuit and lower than the start reference power (Po) When the opening / closing means is smaller than the closing reference value (P1), the opening / closing means is opened. When the power (Pp) of the power supply source is equal to or higher than the closing reference value (P1), the opening / closing means is closed. The grid interconnection inverter device according to claim 1, wherein the grid interconnection inverter device is configured as described above.   The opening / closing means is opened when the power (Pp) of the power supply source is equal to or less than the open reference value (P2) of the opening / closing means set to be equal to or less than the stop reference power (Ps) of the inverter main circuit. The grid interconnection inverter device according to claim 6, wherein the grid interconnection inverter device is provided.

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