JP2009118670A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an AC power supply device that allows smooth power supply to a load, to which power supply is impossible by a single power conversion device due to a power shortage, while increasing total output by connecting a plurality of power conversion devices in parallel. <P>SOLUTION: Each AC power output device PO-1 to PO-n converts DC power from each of individual solar cells 1-i (i=1-n) into AC power and outputs the AC power. A plurality of AC power output devices are connected in parallel so as to supply power to a load by an output line P. One firstly-started AC power output device in the plurality of AC power output devices is set as a master device while the secondly and succeedingly-started AC power output devices are set as slave devices. The master device controls the slave devices so as to execute control relating to power output from the output line and transmits output data of the master device itself to a data circuit D. The slave devices receive the output data of the master device from the data circuit D so as to control power output of themselves. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply apparatus in which a plurality of power conversion apparatuses are connected in parallel to increase the total output power, and power can be supplied to a load that cannot be supplied due to power shortage alone.

  In recent years, as an AC power supply apparatus, as shown in FIG. 5, in order to convert a DC voltage from a solar cell 1 into an AC voltage by a power conversion apparatus 2 and to enable the apparatus itself to operate independently, power conversion Some devices 2 have a constant voltage power supply function capable of always outputting AC 100 V, 200 V, etc. regardless of the size of the load 3.

  On the other hand, power supply companies supply power from many power plants in parallel to large loads, and each power plant distributes the power supplied to the load according to the power supply capacity of each power plant. An AC power supply method is adopted.

Further, a power supply device is disclosed that receives power from a solar cell, operates a plurality of generators connected in parallel, and supplies power from the plurality of generators (for example, Patent Document 1). reference).
Japanese Patent No. 3534914

  When supplying power to a large load using the conventional AC power supply apparatus described above, one AC power supply apparatus can only handle a predetermined output, and when supplying power to a large load, Therefore, it is necessary to consider taking the same method as in the case of supplying power from a plurality of large power plants in parallel.

  However, when a plurality of the conventional AC power supply devices shown in FIG. 5 are connected in parallel, the values of the reference voltages held in the devices themselves are different from each other, and the output conditions affect each other. Is difficult.

  In addition, as described above, it is conceivable to apply the grid connection form in the same way as the operation of the generator of the power generation equipment by applying the power generation equipment technology of the power company. In this case, one of the power supply devices to be operated in parallel may be determined as the main device, and the grid connection operation may be performed with the other power supply device as a slave device at the output of the power supply device that has become the main device.

  However, in the operation of the power supply device, the total power of the power devices connected in parallel must be equal to the power consumed by the load. For this reason, there is a problem that the grid interconnection is difficult to control unlike the normal interconnection.

  The technique described in Patent Document 1 is to connect generators in parallel. However, when the input solar cell has a high power output, the generators are sequentially switched and output from each generator. However, this does not solve the problem of supplying power in parallel to a high load from a plurality of power supply devices.

  The present invention has been made paying attention to the above-mentioned problems, and the AC power output unit consisting of the DC power generation means and the power conversion means alone outputs AC power to a load that cannot supply power due to power shortage. It is an object of the present invention to provide a power supply device that can increase power output smoothly by connecting a plurality of devices in parallel to increase the total output.

  The power supply device according to the present invention includes a plurality of AC power output devices each including a DC power generation unit and a power conversion unit that converts and outputs DC power from the DC power generation unit into AC power. A power supply device that outputs power to the load from the output line, wherein the first activated device among the plurality of AC power output devices is set as a main device, and is activated second and later. The AC power output device set as a slave device, and the master device controls the slave device to perform control related to the power output from the output line, and the AC power output set with the master device Data transmission means for transmitting the output data of the master device itself to the slave device from the device, wherein the slave device receives the output data of the master device by the data transmission means and can output predetermined power to the slave device itself Power of To control the output, when the power supply to the load is insufficient, and performs power supply from the substation in conjunction with power supply from the main apparatus.

  In the power supply apparatus of the present invention, the DC power generation means is a generic name for devices that generate DC power based on natural energy, such as solar cells and wind power generators.

  In the power supply apparatus according to the present invention, each AC power output apparatus includes a means for determining whether or not output data exists in the data transmission means, and when the output data does not exist and does not respond, Is set as the master device, and when the output data exists and responds, the own device can be set as the slave device.

  Further, in the power supply apparatus of the present invention, the main device includes means for determining that the main device itself is down, and when the main device itself is determined to be down, the data transmission means outputs the main device itself. Stop data transmission.

  According to the present invention, a plurality of AC power output devices are connected in parallel to the output line so that power can be output from the common output line. Is set as the master device, and the second or subsequent device is set as the slave device. The slave device receives the output data from the master device and supplies power to the load together with the power supply from the master device. Since this is done, it is possible to expand the scale of the power generation facility as necessary. In addition, since parallel connection can be easily performed, no special adjustment and connection is required during installation.

  Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a block diagram showing a configuration of an AC power supply apparatus according to an embodiment of the present invention.

  The AC power supply device (AC power supply system) according to this embodiment includes individual solar cells 1-1, 1-2,..., 1-n, and these solar cells 1-1, 1-2. ,...,...,..., Power conversion circuits (power conversion means) S-1, S-2,. A plurality of AC power output devices PO-1, PO-2,..., PO-n that are individually configured with Sn are arranged in parallel.

  The power conversion circuits S-1, S-2,..., Sn are set so that any one circuit functions as a main device and the other functions as a slave device. After the setting, the slave device is always current-controlled under the control of the master device, and each power conversion circuit S-1, S-2,. Are supplied evenly.

  In the embodiment shown in FIG. 1, the case where the power conversion circuit S-1 operates as a main device is shown. The power conversion circuit S-1 includes an input voltage / current detection unit 2-1 that detects a voltage / current of a DC voltage input from the solar battery 1-1, and a DC voltage input from the solar battery 1-1. DC / AC converter 3-1 that converts AC to AC voltage, output voltage / current detection unit 4-1 that detects output voltage / current output to power output line P, power output from itself, and others And a control unit 5-1 that performs control for setting the power output from the power conversion circuit to a predetermined value. The control unit 5-1 includes a CPU 6-1 that executes control arithmetic processing, a high-speed communication unit 7-1 connected to the data line D, and a reference voltage source 8 that inputs a reference voltage to the CPU 6-1 for comparison control. -1.

Similarly to the power conversion circuit S-1, the power conversion circuits S-2,..., Sn operating as slave devices are also input voltage / current detection units 2-2,. DC / AC converters 3-2,..., 3-n, output voltage / current detection units 4-2,..., 4-n, control units 5-2,. n.
The control units 5-1, 5-2,..., 5-n of the power conversion circuits S-1, S-2,. The power conversion circuit of the device that has the same control program (software) including that for the slave device and the slave device and that has started the operation first among the plurality of AC power supply devices PO-1 to PO-n Then, it sets itself as a master device using a master / slave setting program, and then executes the program for the master device. The power conversion circuit of the other AC power supply device executes the main / slave setting program at the start of operation, and sets itself as a slave device when the master device is already set. Run the program.

  Next, the processing operation of the AC power supply apparatus according to this embodiment will be described. First, in the case where none of the power conversion circuits S-1, S-2,..., Sn is set as the main device, the power conversion circuit S-1 first starts operating. This will be described with reference to the flowchart shown in FIG.

  First, when the operation start switch is turned on and the operation starts, it is determined whether or not the operation in step ST1 is started, and then the process proceeds to step ST2. In step ST2, line data is taken from line D via high-speed communication unit 7-1. Subsequently, the process proceeds to step ST3.

  In step ST3, it is determined whether or not there is line data. As will be described later, when any of the power conversion circuits S-1, S-2,..., Sn is already set in the main device, the power conversion that is the main device is applied to the line D. Power is supplied from the circuit to the load, and the output power data is output through the high-speed communication unit 7-i (i = 1 to n). On the other hand, when the main apparatus has not been set, no output power data exists on the line D.

  In step ST3, the determination is made when the main apparatus has not yet been set, and there is no communication data (output data) on the line D. Therefore, the determination is NO, and the process proceeds to step ST4. In step ST4, since no main device has been set yet, the power conversion circuit S-1 is set as the main device in its own device. Thereafter, the process proceeds to a normal power output process shown in FIG.

  On the other hand, assuming that any other power conversion circuit is already set as the main device, the determination of whether or not the line data is present in step ST3 is YES in the processing when the operation start switch shown in FIG. 2 is ON. The process moves to step ST5. In step ST5, since the main device is already set in another power conversion circuit, the own device is set as a slave device. Thereafter, the process proceeds to the power output process of the normal slave device shown in FIG.

  Next, the power output processing operation of the main apparatus will be described with reference to the flowchart shown in FIG. When this processing routine is entered, first, in step ST11, DC power from the solar cell 1-1 is received and converted to AC, and output to the power output line P is started.

  Next, in step ST12, the output voltage of the output line P is held at a constant voltage (for example, 60 Hz, AC 100 V). Subsequently, the process proceeds to step ST13.

  In step ST13, its own output as the main device is sent to the line D via the high-speed communication unit 7-1. The output data of the master device is used for processing judgment of output power control in the slave device. Next, the process proceeds to step ST14.

  In step ST14, the output power output to the output line P is detected by the output voltage / current detection unit 4-1. If the load connected to the power output line P consumes power, the voltage of the power line P temporarily decreases. Further, as will be described later, when there is power output from the slave devices S-2,..., Sn connected to the grid in addition to the main device S-1, the output line P is temporarily output. The voltage of P becomes large. In order to detect these, the output voltage is detected by the output voltage / current detector 4-1 in step ST14.

  Next, the process proceeds to step ST15. In step ST15, it is determined whether there is an output change based on the detected output of the output line P. Subsequently, in step ST16, it is determined whether the output is decreasing.

  Here, if the load connected to the output line P consumes power as described above, the voltage of the output line P temporarily decreases. In this case, the determination in step ST16 is YES, and the process proceeds to step ST17. To do.

  In step ST17, control is performed so as to increase the output voltage of the main device S-1 and maintain the output voltage of the main device S-1 at a constant value.

  Further, when the own output of the master device S-1 becomes a predetermined value or more, the slave device S-2 (S-3,..., Sn) uses the own output data sent to the line D to Receives and starts grid connection operation. As a result, power is also output from the slave device S-2 to the output line P, and the power of the output line P temporarily becomes excessive (voltage increases). In such a case, the determination in step ST16 is NO due to the increase in output. By this determination, the process proceeds to step ST18.

  In step ST18, in order to decrease the output increased by the slave device and return it to a constant value, main device S-1 reduces its own output. Next, the process proceeds to step ST19. In step ST19, the own output increased in step ST17 or decreased in step ST18 is sent to line D.

  Next, the power output processing operation of the slave device S-2 will be described with reference to the flowchart shown in FIG. A normal control operation is entered, and in step ST21, it is determined whether or not the slave device S-2 is connected in parallel. Since only the main device S-1 outputs power to the load at the beginning of the operation, the determination is NO and the process proceeds to step ST22.

  In step ST22, the high-speed communication unit 7-2 receives the output data (main output data) of the main device S-1 from the line D. Subsequently, the process proceeds to step ST23. In step ST23, it is determined whether or not the main output data is larger than a predetermined reference value K1 (for example, 50 W).

  The reference value K1 is a reference value of the output data of the master device that is used as a criterion for determining whether or not the slave device S-2 (S-3,..., Sn) is to be grid-connected. If the main output data is less than or equal to the reference value K1, the determination returns in step ST23, and the process returns without shifting to grid interconnection. If the main output data is greater than K1, the determination in step ST23 is YES, and the process proceeds to step ST24, where the slave device S-2 starts output by grid connection. That is, the parallel connection operation is started. Then return.

  Thereafter, in step ST21, since the slave device S-2 has already entered the parallel connection operation, the determination is YES, and the process proceeds to step ST25. In step ST25, the main output data from the line D is received by the high-speed communication unit 7-2. Then, the process proceeds to step ST26. In step ST26, it is determined whether or not the main output data is smaller than a reference value K2 (for example, 20W: K1 >> K2). When the power consumption of the load is small, the power supply to the load is sufficient only by the main output of the main device S-1, and when the main output data is smaller than the reference value K2 so that grid connection is not necessary, Thus, the process proceeds to step ST30, and the slave device S-2 is disconnected from the parallel connection. On the other hand, if the main output data is greater than or equal to the reference value K2, the process proceeds to step ST27.

  In step ST27, it is determined whether main output data = own output data. In the case of determination YES, the outputs of the slave device S-2 and the master device S-1 are equalized, and it is not necessary to control the output of the slave device any more, so the process proceeds to step ST29, and the output of itself is not changed. Return in a stable state. In the case of determination NO in step ST27, the process proceeds to step ST28, and the output control of the own device is performed so that the own output data becomes equal to the main output data.

  In the AC power supply apparatus according to the above embodiment, the transition from the main apparatus S-1 alone to the parallel connection operation with the slave apparatus S-2 will be described using a specific example. Initially, when 100 W of electric power is supplied from only the main device S-1 to a 100 W load, the main output data sent from the main device S-1 to the line D is 100 W. In S-2, when a parallel connection operation is started and 30 W is output to the output line P, the outputs of the main device and the slave device are combined and the output line P is instantaneously 130 W, and the output is excessive with respect to the load 100 W. When the main device detects this excessive output and lowers its output to, for example, 70 W so as to obtain a predetermined output voltage, this 70 W is sent to the line D as main output data.

  The main output data 70W at this time is larger than the own output data 30W of the slave device S-2, and the slave device S-2 further increases its own output and outputs, for example, 50 W to the output line P. As a result, the voltage of the output of the output line P rises instantaneously to 120 W, for example, and exceeds the load 100 W.

  In the main device S-1, this excessive output is detected, and the output of the own device is further lowered to a predetermined output voltage, for example, 50 W. When the main output data 50W from the master device S-1 is taken into the slave device S-2, the master output data and the slave device output data at this time become equal. Thereafter, both the master device and the slave device are output. Without changing the output, the output 50 W is maintained as it is (100 W for both). As described above, when the slave device S-2 having the same rating is operated in parallel to the main device S-1, the load is stably supplied to the load 100W at 50W and 50W with an equal divided output. Next, when the slave device S-3 having the same rating is also operated in parallel, the load 100 is equally divided and output at 33.3W, 33.3W, and 33.3W.

  In the AC power supply apparatus according to this embodiment, for example, when the AC power output apparatus PO-1 is set as the main apparatus and is operated in parallel, the power conversion of the AC power output apparatus PO-1 as the main apparatus is performed. When the circuit S-1 is down, the power conversion circuit S-1 itself detects down and the main output data output to the line D from the high-speed communication unit 7-1 is set to 0. By executing the process, the master device is set to itself, and when the down device (original master device) recovers, it is returned as a slave device.

  In this way, when the main device goes down, the main device can be changed to another device, and the power supply by the parallel processing as before can be continued.

It is a block diagram which shows the circuit structure of the alternating current power supply device which is one Embodiment of this invention. . It is a flowchart explaining the setting process of the main apparatus at the time of the operation | movement start in each power conversion circuit of the same embodiment AC power supply apparatus, and a subordinate apparatus. It is a flowchart explaining the power output control process in the power converter circuit set with the main apparatus of the alternating current power supply apparatus of the embodiment. It is a flowchart explaining the power output control process in the power converter circuit set as the slave apparatus of the alternating current power supply apparatus of the embodiment. It is a schematic block diagram which shows the structure of the conventional common AC power supply apparatus.

Explanation of symbols

S-1, S-2,..., Sn power conversion circuit 1-1, 1-2,..., 1-n solar cell 2-1, 2-2,. Input voltage / current detection unit 3-1, 3-2,..., 3-n DC / AC converter 4-1, 4-2,..., 4-n Output voltage / current detection unit 5-1, 5-2,..., 5-n control unit 6-1, 6-2,.
7-1, 7-2, ..., 7-n High-speed communication unit 8-1, 8-2, ..., 8-n Reference voltage source P Power output line D Data line PO-1, PO-2 ..., PO-n AC power output device

Claims (3)

A plurality of AC power output devices comprising DC power generation means and power conversion means for converting and outputting DC power from the DC power generation means to AC power, are connected in parallel to the output line and are connected to the load from the output line. A power supply device that outputs power,
One of the plurality of AC power output devices that is activated first is set as a master device, the AC power output device that is activated second or later is set as a slave device, and the master device is a slave device. To control the power output from the output line,
From the AC power output device set with the master device, comprising data transmission means for transmitting output data of the master device itself to the slave device,
The slave device receives the output data of the master device from the data transmission means, controls the power output of the slave device itself so that predetermined power can be output, and when the power supply to the load is insufficient, the slave device A power supply device that supplies power from the slave device together with power supply from the device.     Each of the AC power output devices includes means for determining whether or not output data exists in the data transmission means, and when the output data does not exist and does not respond, sets the own device as the main device, and outputs data The power supply apparatus according to claim 1, wherein when there exists and responds, the apparatus is set as a slave apparatus.     The main device includes means for determining that the main device itself is down, and when the main device itself is determined to be down, the data transmission means stops transmission of output data of the main device itself. The power supply device according to claim 1 or 2.