JP2008029091A - System interlocking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system interlocking device which can adjust load voltage to a specified voltage value quickly after opening a switch. <P>SOLUTION: This device is equipped with a shut-off control circuit 9 which outputs a shut-off control signal 9a for opening a switch 3 by detecting the abnormal state of a system power source 1, an average calculating circuit 17 which calculates an average load current value 17a in normal operation of the system power source 1, a constant voltage control circuit 16 which outputs a constant voltage control current command 16a for obtaining the constant output voltage of a power converter 4, based on the detected load voltage value 13a, and a selecting circuit which selects and outputs an output current command 6a to the power converter 4 from among a plurality of inputs. It selects the average load current value 17a calculated in normal operation of the system power source 1 as an output current command 6a for a specified period before the selecting circuit selects the constant voltage control current command 16a as the output current command 6a after the break control signal 9a is inputted from the break control circuit 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a grid interconnection device that interconnects another energy source to a grid power supply via a power converter and supplies stable power to a load when the grid power supply is abnormal.

  A conventional system interconnection in which a system power source and a load are connected via a switch, a second power source is connected to the load side of the switch via a power converter, and the second power source is linked to the system power source. The device includes a current detector that detects a load current value, and a constant voltage that outputs a constant voltage control current command for setting the output voltage of the power converter to a predetermined constant voltage based on the detected load voltage value. A control circuit; and a selector that selects and outputs an output current command for the power converter from a plurality of inputs, opens the switch when an abnormality in the system power supply is detected, and outputs the load current as an output current command. There has been proposed a method of selecting the constant voltage control current command as an output current command by selecting a value and detecting the interruption of the switch current (see, for example, Patent Document 1).

JP 2003-153450 A

  In the grid interconnection device described in Patent Literature 1, when a system power supply abnormality is detected, the switch is opened and a load current value is selected as an output current command. After that, when the switch current is detected to be interrupted, the constant voltage control current command is selected as the output current command, whereby the power converter is controlled at a constant voltage, and stable power is supplied to the load. However, when the load voltage drops after the switch is opened, the constant voltage control circuit determines that the constant voltage control current is based on a load voltage value smaller than the load voltage value before the abnormality occurs in the system power supply. There is a problem that it takes time until the load voltage recovers to a predetermined constant voltage value because the selector operates to perform constant voltage control of the power converter by this constant voltage control current command.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a grid interconnection device capable of quickly setting a load voltage to a predetermined constant voltage value after the switch is opened. It is to be.

  In the grid interconnection device according to the present invention, a system power source and a load are connected via a switch, a second power source is connected to a load side of the switch via a power converter, and the second power source is used as a system power source. In the interconnected system interconnection device, an interruption control circuit that outputs an interruption control signal that opens the switch by detecting an abnormal state of the system power supply, and an average value that calculates the average load current value when the system power supply is normal An arithmetic circuit, a constant voltage control circuit that outputs a constant voltage control current command for setting the output voltage of the power converter to a predetermined constant voltage based on the detected load voltage value, and power from a plurality of inputs A selection circuit that selects and outputs an output current command to the converter, and the selection circuit selects and outputs a constant voltage control current command as an output current command after the cutoff control signal is input from the cutoff control circuit. Before Period, as the output current command, and outputs select the average load current value calculated during normal system power source.

  The grid interconnection apparatus according to the present invention connects a system power source and a load via a switch, connects a second power source to the load side of the switch via a power converter, and connects the second power source to the system. In the grid interconnection device linked to the power supply, the abnormal state of the system power supply is detected, the cutoff control circuit that outputs the cutoff control signal for opening the switch, and the cutoff of the switch current is detected. Based on the detected load voltage value, the interruption state detection circuit that outputs the status signal, the current detector that detects the load current value, the average value calculation circuit that calculates the average load current value when the system power supply is normal, A constant voltage control circuit that outputs a constant voltage control current command for setting the output voltage of the power converter to a predetermined constant voltage, and a selection circuit that selects and outputs the output current command for the power converter from a plurality of inputs When The selection circuit is configured to select and output a load current value as an output current command when the cutoff control signal is input from the cutoff control circuit, and after the cutoff state signal is input from the cutoff state detection circuit, For a predetermined period before the constant voltage control current command is selected and output as the output current command, the average load current value calculated when the system power supply is normal is selected and output as the output current command.

  According to the present invention, the load voltage can be quickly set to a predetermined constant voltage value after the switch is opened.

  In order to explain the present invention in more detail, it will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
FIG. 1 is a block configuration diagram showing a grid interconnection device according to Embodiment 1 of the present invention. In FIG. 1, 1 is a system power supply, 2 is a load, 3 is a high-speed switch that connects the system power supply 1 and the load 2, and 4 is a power converter that is connected between the high-speed switch 3 and the load 2 and can be controlled bidirectionally. And 5 is a second power source. Reference numeral 6 denotes a current command generation circuit which generates an output current command 6a for the power converter 4, which will be described later. Reference numeral 7 denotes a current control circuit for controlling the output current of the power converter 4 to match the output current command 6a. A pulse generation circuit 9 for generating an operation command for the power converter 4 is a cutoff for opening the high-speed switch 3 by detecting a voltage abnormality on the load 2 side of the high-speed switch 3, that is, an abnormal state of the system power supply 1. This is a cutoff control circuit that outputs a control signal 9a.

  10 is a current detector that detects a current flowing from the high-speed switch 3 to the load 2 side, that is, an energization current of the high-speed switch 3 (hereinafter referred to as “switch current”), and 11 is a switch current cutoff state, By detecting that it has become 0, the shutoff state detection circuit 12 that outputs a shutoff state signal 11a indicating that the system power supply 1 is in the shutoff state, 12 is a current flowing through the load 2 (hereinafter referred to as “load current”). A current detector for detecting, a voltage detector for detecting a voltage on the load 2 side of the high-speed switch 3 (hereinafter referred to as “load voltage”), and a current detector for detecting an output current of the power converter 4. .

  The cutoff control signal 9 a output from the cutoff control circuit 9 is input to the high speed switch 3 and the current command generation circuit 6. The interruption state signal 11 a output from the interruption state detection circuit 11 is input to the current command generation circuit 6. On the other hand, the detection value of the switch current detected by the current detector 10 is supplied to the cutoff state detection circuit 11 and the detection value of the load current detected by the current detector 12 (hereinafter referred to as “load current value 12a”). The detected value of the load voltage detected by the voltage detector 13 (hereinafter referred to as “load voltage value 13a”) is supplied to the current command generating circuit 6 and the cutoff control circuit 9 by the current command generating circuit 6. The detected value of the output current of the power converter 4 detected by 14 is input to the current control circuit 7 respectively.

  Next, the configuration of the current command generation circuit 6 will be described. FIG. 2 is a block diagram showing the details of the current command generation circuit according to the first embodiment of the present invention. In FIG. 2, reference numeral 15 denotes a grid interconnection current command generation circuit that generates and outputs a grid interconnection current command 15a for setting the supply system to the load 2 to the grid power supply 1 when the grid power supply 1 is in a normal state. A constant voltage control circuit 16 generates and outputs a constant voltage control current command 16a for setting the output voltage of the power converter 4 to a predetermined constant voltage based on the load voltage value 13a input from the voltage detector 13. , 17 is an average value calculation circuit that calculates and outputs an average value of the load current value 12a input from the current detector 12 for a predetermined period (hereinafter referred to as “average load current value 17a”) when the system power supply 1 is normal. , 18 based on the cutoff control signal 9a input from the cutoff control circuit 9 and the cutoff state signal 11a input from the cutoff state detection circuit 11, the grid interconnection current command 15a and the load current value 12a input. Average load current value 17a, a selector for selecting one of a constant voltage control current command 16a, and outputs the selected one as the output current command 6a to the power converter 4 (selection circuit). That is, the current command generation circuit 6 includes a grid interconnection current command generation circuit 15, a constant voltage control circuit 16, an average value calculator 17, and a selector 18.

  Next, the operation of the grid interconnection device having the above configuration will be described. FIG. 3 is a timing chart for explaining the operation of the grid interconnection apparatus according to Embodiment 1 of the present invention. 1 to 3, when the system power supply 1 is operating normally, the power of the system power supply 1 is supplied to the load 2 via the high-speed switch 3. In the current command generation circuit 6, the grid connection current command 15 a is selected as the output current command 6 a by the selector 18 and is output to the current control circuit 7. As a result, the power converter 4 outputs a current based on the grid connection current command 15a, and the output from the second power supply 5 is connected to the grid power supply 1 and is operated in a grid connection.

  When an abnormality occurs in the system power supply 1 due to a system fault or the like, the shut-off control circuit 9 latches a drop in the load voltage, that is, a voltage abnormality based on the load voltage value 13a detected by the voltage detector 13, and the high speed A cutoff control signal 9a is output to the switch 3 and the current command generation circuit 6. In the high-speed switch 3, when the cutoff control signal 9 a is input from the cutoff control circuit 9, the internal contact is opened by a mechanical operation. Further, in the current command generation circuit 6, when the cutoff control signal 9a is input from the cutoff control circuit 9, the output current command 6a selected by the selector 18 is changed from the grid connection current command 15a to the load current value. It is switched to 12a. As a result, the power converter 4 is operated and controlled so that the output current matches the load current value 12a. In the high-speed switch 3, the arc current that continues to flow even after being opened by mechanical operation is quickly generated. It becomes 0 and the interruption is completed.

  When the switch current is cut off by the above operation, the cut-off state detection circuit 11 detects that the switch current has become 0, and the cut-off state detection circuit 11 outputs a cut-off state signal 11a to the current command generation circuit 6. The In the current command generation circuit 6, when the cutoff state signal 11a is input from the cutoff state detection circuit 11, the output current command 6a selected by the selector 18 is switched from the load current value 12a to the average load current value 17a. As a result, the power converter 4 is controlled so that the output current matches the average load current value 17a.

  In the current command generation circuit 6, the output current command 6a is further switched to the constant voltage control current command 16a after a predetermined time has elapsed since the selector 18 switched the output current command 6a to the average load current value 17a. That is, the selector 18 detects the interruption state signal 11a from the interruption state detection circuit 11, and then selects the average load current value 17a as the output current command 6a only for a predetermined time, and selects the constant voltage control current command 16a after the predetermined time has elapsed. The output current command 6a is selected. As a result, the power converter 4 is subjected to constant voltage control so that the output current matches the constant voltage control current command 16a, and supplies stable power to the load 2.

  According to the first embodiment of the present invention, the selector 18 receives the cutoff state signal 11 from the cutoff state detection circuit 11, and then selects and outputs the constant voltage control current command 16a as the output current command 6a. For a predetermined period, the average load current value 17a calculated when the system power supply 1 is normal is selected and output as the output current command 6a. As a result, even when the load voltage decreases after the high-speed switch 3 is opened and the load current decreases as a result, the power converter 4 has an average load current within a predetermined range calculated when the system power supply 1 is normal. Since the control is performed based on the value 17a, the time until the load voltage recovers to a predetermined constant voltage value can be greatly shortened.

  In the first embodiment of the present invention, the high-speed switch 3 that opens and closes the mechanical contact has been described. However, instead of the high-speed switch 3, no arc current is generated. When configured, it is possible to omit the period for selecting the load current value 12a as the output current command 6a in FIG.

It is a block block diagram which shows the grid connection apparatus in Embodiment 1 of this invention. It is a block block diagram which shows the detail of the current command generation circuit in Embodiment 1 of this invention. It is a timing chart explaining operation | movement of the grid connection apparatus in Embodiment 1 of this invention.

Explanation of symbols

1 system power supply, 2 load, 3 high-speed switch, 4 power converter,
5 Second power supply, 6 Current command generation circuit, 6a Output current command,
7 Current control circuit, 8 Pulse generation circuit, 9 Shutdown control circuit,
9a interrupting control signal, 10 current detector, 11 interrupting state detection circuit,
11a Breaking state signal, 12 Current detector, 12a Load current value,
13 voltage detector, 13a load voltage value, 14 current detector,
15 grid connection current command generation circuit, 15a grid connection current command,
16 constant voltage control circuit, 16a constant voltage control current command, 17 average value calculation circuit,
17a Average load current value, 18 selector

Claims (2)

A grid power source and a load are connected via a switch, a second power source is connected to the load side of the switch via a power converter, and the second power source is linked to the grid power source. In the system equipment,
By detecting an abnormal state of the system power supply, a cutoff control circuit that outputs a cutoff control signal for opening the switch, and
An average value calculation circuit for calculating an average load current value when the system power supply is normal;
A constant voltage control circuit that outputs a constant voltage control current command for setting the output voltage of the power converter to a predetermined constant voltage based on the detected load voltage value;
A selection circuit for selecting and outputting an output current command for the power converter from a plurality of inputs;
With
The selection circuit has a predetermined period before the constant voltage control current command is selected and output as the output current command after the cutoff control signal is input from the cutoff control circuit, and the system as the output current command. A grid interconnection device that selects and outputs the average load current value calculated when the power supply is normal. A grid power source and a load are connected via a switch, a second power source is connected to the load side of the switch via a power converter, and the second power source is linked to the grid power source. In the system equipment,
By detecting an abnormal state of the system power supply, a cutoff control circuit that outputs a cutoff control signal for opening the switch, and
An interruption state detection circuit that outputs an interruption state signal by detecting an interruption state of the switch current;
A current detector for detecting the load current value;
An average value calculation circuit for calculating an average load current value when the system power supply is normal;
A constant voltage control circuit that outputs a constant voltage control current command for setting the output voltage of the power converter to a predetermined constant voltage based on the detected load voltage value;
A selection circuit for selecting and outputting an output current command for the power converter from a plurality of inputs;
With
The selection circuit selects and outputs the load current value as the output current command when the cutoff control signal is input from the cutoff control circuit, and the cutoff state signal is input from the cutoff state detection circuit. A predetermined period before selecting and outputting the constant voltage control current command as the output current command, selecting the average load current value calculated when the system power supply is normal as the output current command. A grid interconnection device characterized by output.

Images