JP4606887B2 - Inverter operation method - Google Patents

Description

  The present invention relates to a power supply system that converts a direct current output from a direct current power source such as a solar battery into an alternating current output by a plurality of inverter devices and supplies the power to a system power source. The present invention relates to a technique for switching a master inverter device.

  FIG. 5 is a block diagram of a conventional power supply system. In the figure, the power supply system includes a direct current power source DC composed of solar cells, and a first inverter device PS1 to an nth inverter device PSn that are connected in parallel to the direct current power source DC and convert a direct current output into an alternating current output by an inverter. And a power detector DS that detects an output power value from the DC power source DC, and switches SW1 to SWn that open and close the inverter devices connected to the DC power source DC.

  In FIG. 5, the first inverter device PS1 is formed by a first inverter control circuit CW1 and a first inverter circuit PC1, and the second inverter device PS2 is formed by a second inverter control circuit CW2 and a second inverter circuit PC2. The n-th inverter device PSn is formed of an n-th inverter control circuit CWn and an n-th inverter circuit PCn.

  In the power supply system, based on a predetermined rule (for example, an inverter device having a small integrated power value), the first inverter device PS1 is a master inverter device, and the second inverter device PS2 to the nth inverter device PSn are slave inverter devices. Subsequently, the first inverter control circuit CW1 of the first inverter device PS1, which is the master inverter device, determines the number of inverter devices to be activated according to the output power value for each predetermined period from the DC power source DC. Next-cycle activation candidate slave inverters are selected from the slave inverter devices in the descending order of the integrated power value of each slave inverter device for the number of next-cycle activation units.

  Subsequently, the inverter control circuit of each selected slave inverter device performs activation of the inverter circuit and closing of the switch according to the selection.

  Next, the switching operation of the master inverter device will be described with reference to the master inverter device switching timing chart shown in FIG. At time t = t1 shown in FIG. 6, the master inverter device detects the output power value from the DC power source DC and determines that the solar radiation starts when the output power value exceeds a predetermined reference power value, and every period from the DC power source DC. The number of inverter devices to be started is determined according to the output power value of each of the slave inverter devices, and the next cycle start candidate slave inverter is started from the number of all the slave inverter devices in the descending order of the integrated power value of each slave inverter device. To do. Next, at time t = t2, when the output power value from the DC power source DC is detected and falls below the reference power value, it is determined that the solar radiation has ended, and the master inverter device stops starting each selected slave inverter device. Of all the slave inverter devices, the one with the smallest integrated power value is selected as the next master inverter device.

  At time t = t3, the next master inverter device selected at the time t2 detects the output power value from the DC power source DC and determines that the solar radiation starts again when the output power value exceeds the reference power value, and the next master inverter device Determines the number of inverter devices to be activated according to the output power value for each cycle from the DC power source DC, and from among the slave inverter devices, the number of units activated for the next cycle in ascending order of the integrated power value of each slave inverter device. Only the next cycle start candidate slave inverter is started. Next, at time t = t4, when the output power value from the DC power source DC is detected and becomes equal to or less than the reference power value, it is determined that the solar radiation has ended, and the master inverter device stops starting each selected slave inverter device. Of all the slave inverter devices, the one with the smallest integrated power value is selected as the next master inverter device. Thereafter, the same processing as above is repeated.

  In the above description, when an overvoltage or overcurrent abnormality occurs in the system power supply during the daytime period shown in FIG. 6, the master inverter device opens the first switch SW1 to the nth switch SWn shown in FIG. The supply of output power from all inverter devices of is stopped. Subsequently, when the abnormality of the system power supply is canceled, all the inverter devices perform self-diagnosis, exchange the self-diagnosis result by the data communication means, and minimize the communication address rank unique among normal inverter devices (for example, 1 No.) is determined as the master inverter device.

  Patent Document 1 discloses a technique for switching the master inverter device in units of one day as described above.

  Further, Patent Document 2 discloses a technique in which each inverter device performs self-diagnosis in response to an abnormality in a system power supply or the like, and determines a master inverter device based on a unique communication address among normal inverter devices. .

JP 2000-305633 A JP 2004-173388 A

  In a power supply system that supplies power to a system power supply by converting direct current output from a direct current power source such as a solar cell into alternating current output by a plurality of inverter devices, the number of inverter devices started according to the output power value for each predetermined period If the master inverter device that determines the failure fails, the master function cannot be transferred to the next master inverter candidate, and the startup number of inverter devices cannot be determined according to the output power value for each cycle, so that stable power supply to the system power supply Can not be.

  Also, if an overvoltage or overcurrent abnormality occurs in the system power supply, the supply of output power from all the inverter devices that are running is stopped, and when the above system power supply abnormality is released, each inverter device performs self-diagnosis, The self-diagnosis result is exchanged by the data communication means, and among the normal inverter devices, the minimum unique communication address rank is set as the master inverter device. However, when the master inverter device is selected with the unique communication address, the same inverter device is selected as the master inverter device after the abnormality of the system power supply is canceled, so the startup time is uniform between other inverter devices. There is no progress. Then, this invention is providing the operating method of the inverter apparatus which can solve the subject mentioned above.

  In order to solve the above-described problem, the first invention is configured such that a plurality of inverter devices are connected in parallel to a DC power source, and an output power value of the DC power source is selected from the plurality of inverter devices at predetermined intervals. The n-th cycle master inverter device determines the number of next-cycle start devices according to the output power value, and the number of inverter devices among all the inverter devices is determined. The next cycle start candidate inverters are selected as the next cycle start candidate inverters in ascending order of the combination value of at least one of the integrated power value, the total number of start times, and the total start time, and randomly selected from the next cycle start candidate inverters. A periodic master inverter candidate is selected, and at the start of the (n + 1) th period, the master inverter device of the nth period In the operation method of the inverter device in which the master function is transferred to the next master inverter candidate after starting the data and the operation is repeated thereafter, the master inverter device in the nth cycle is selected when the next cycle master inverter candidate is selected. A master inverter order is randomly assigned to the periodic start candidate inverters, and the one with the smallest master inverter order is selected as the next period master inverter candidate. When the master inverter device in the (n + 1) th period fails, In the inverter apparatus, the inverter apparatus having the lowest master inverter rank is transferred to the master inverter apparatus.

  According to a second aspect of the present invention, when the master function is transferred from the n-th cycle master inverter device to the next cycle master inverter candidate, the overvoltage or When an overcurrent abnormality occurs, one or both of the master inverter devices stop supplying output power from all of the activated inverter devices, and then the abnormality of the system power supply is released. One master inverter device is determined from the two master inverter devices based on a predetermined rule, and the determined master inverter device starts supply of output power from the stopped inverter device. An operation method for an inverter device according to Item 1.

  According to a third aspect of the invention, in the method of operating an inverter device according to claim 2, wherein the master inverter device determined by the predetermined rule is a next cycle master inverter candidate selected in the nth cycle. is there.

  According to a fourth aspect of the present invention, the master inverter device determined by the predetermined rule has a minimum communication address order unique to the next cycle start candidate inverter selected in the nth cycle. It is a driving | running method of the described inverter apparatus.

  According to the first aspect of the invention, even if the master inverter device fails, the master inverter device having the lowest master inverter rank among the inverter devices that are being activated is transferred to the master inverter device. The functions can be transferred, the number of inverter devices to be activated can be determined according to the output power value for each cycle, and stable power supply to the system power supply is possible.

  According to the second invention, when the master function is transferred from the master inverter device to the next period master inverter device, an overvoltage and overcurrent abnormality occurs in the system power supply, and then the abnormality of the system power supply is released. Even if two master inverter devices are juxtaposed, one master inverter device is determined based on a predetermined rule, so that the juxtaposition of two master inverter devices can be prevented, and the system power supply Stable power supply is possible.

  According to the third invention, since the master inverter device selects the next master inverter device determined before the occurrence of the abnormality, it is possible to make the startup time uniform between the master inverter device and the other inverter devices. Become.

  According to the fourth aspect of the present invention, in order to select the minimum of the communication address rank inherent in the next cycle start candidate inverter determined before the occurrence of abnormality in the master inverter device as the next master inverter device, the master inverter device and other inverters It is possible to make the startup time uniform with the apparatus.

[Embodiment 1]
FIG. 1 is a block diagram of a power supply system according to an embodiment of the present invention. In the figure, the same reference numerals as those in the block diagram of the prior art power supply system shown in FIG.

  In FIG. 1, the power supply system includes a direct current power source DC composed of solar cells, and a first inverter device PS1 to an nth inverter device PSn that are connected in parallel to the direct current power source DC and convert a direct current output into an alternating current output by an inverter. And a power detection unit DS that detects an output power value from the DC power source DC, and switches SW1 to SWn that open and close each inverter device connected to the DC power source DC.

  The first inverter device PS1 is formed by a first inverter main control circuit CO1 and a first inverter circuit PC1, and the second inverter device PS2 is formed by a second inverter main control circuit CO2 and a second inverter circuit PC2. The nth inverter device PSn is formed of an nth inverter main control circuit CON and an nth inverter circuit PCn.

  The first inverter main control circuit CO1 shown in FIG. 1 is formed by the output power calculation circuit PA, the main control circuit MA, and the transmission / reception circuit TC shown in FIG. 2, and the second inverter main control circuit CO2 to the nth inverter main control. The circuit CON is also formed of the same circuit as described above.

  For example, if the first inverter device PS1 is a master inverter device, the output power calculation circuit PA of the first inverter main control circuit CO1 calculates the output power value from the DC power source DC for each predetermined period to determine the number of units to be started. decide. Next, the main control circuit MA performs the next cycle by the number of the next cycle starting units in ascending order of the integrated power value, the integrated starting number, and the integrated starting time of the first inverter device PS1 to the nth inverter device PSn as all inverter devices. A slave inverter device that is a start candidate is selected, and then a next cycle master inverter device is randomly selected from each slave inverter device that is a next cycle start candidate, and each slave inverter device that is the next cycle start candidate Is randomly assigned a master inverter rank. The transmission / reception circuit TC of the master inverter device transmits the next cycle activation candidate selection signal from the main control circuit MA to each slave inverter device and receives the next cycle activation candidate reception signal sent from each slave inverter device, Transmit to the main control circuit MA.

  Next cycle start candidate selection signal and next cycle master inverter candidate select signal are transmitted from the first inverter device PS1 which is the master inverter device to each slave inverter device which is the next cycle start candidate. After the slave inverter device is activated, for example, if the next period master inverter device is the second inverter device PS2, the second inverter device PS2 receives the received signal to which the master function is transferred, and the first inverter device PS1 is the master inverter device. To a slave inverter device.

  When power is supplied to the system power supply and the first inverter device PS1, which is the master inverter device, fails, the slave inverter device having the lowest master inverter rank among the active slave inverter devices is turned into the master inverter device. .

  Next, the operation of the present invention will be described with reference to the flowchart shown in FIG.

  In step 10 shown in FIG. 3, among the inverter devices connected in parallel to a plurality of units, a predetermined inverter device is a master inverter device, for example, the first inverter device PS1 is a master inverter device. The first inverter device PS1, which is the master inverter device, determines the number of units to be activated in the next cycle according to the output power value in the nth cycle, and from among all the inverter devices, the accumulated power value, the accumulated number of activations, and the accumulated number of each inverter device The next cycle start candidate inverters are selected by the number corresponding to the number of the next cycle start in ascending order of at least one combination value of start times.

  In Step 20, the first inverter device PS1 that is the master inverter device randomly selects the master inverter device of the next cycle from among the slave inverter devices that are candidates for the next cycle activation selected in the nth cycle (for example, The second inverter device PS2 is set as the next master inverter device), and the master inverter ranking is randomly given to each slave inverter device that is a candidate for the next period activation.

  In step 30, the next cycle activation candidate selection signal and the next cycle master inverter candidate selection signal are transmitted from the first inverter device PS1 which is the nth cycle master inverter device to each slave inverter device which is the next cycle activation candidate. to start.

  In step 40, at the start of the (n + 1) -th cycle, a selection signal is transmitted from the first inverter device PS1, which is the master inverter device in the n-th cycle, to each slave inverter device that is the next cycle start candidate, and each of the slave inverter devices described above After starting, the second inverter device PS2 transfers the master function, and the first inverter device PS1 changes from the master inverter device to the slave inverter device.

  Subsequently, the second inverter device PS2 determines the number of slave inverter devices to be activated in the (n + 2) cycle in accordance with the output power value in the (n + 1) cycle, and integrates each inverter device from all the inverter devices. Each of the selected slaves is selected as the start candidate inverter of the (n + 2) period in the order of the combination number of at least one of the power value, the number of times of integrated start, and the integrated start time in the order of the number of the start of the (n + 2) period. A master inverter ranking of the (n + 2) -th cycle is randomly assigned to the inverter device. Thereafter, the same operation as described above is repeated to update the master inverter device sequentially.

  If the master inverter device fails during the process of the flowchart shown in FIG. 3 described above, the process of the flowchart shown in FIG. 4 is started.

  In step 100 shown in FIG. 4, each selected slave inverter device confirms whether its own mode is the master inverter device or the slave inverter device, and confirms the master inverter order set in each slave inverter device.

  In step 200, it is determined whether or not there are two master inverter devices among the selected slave inverter devices. If YES, the process proceeds to step 300, and if NO, the process proceeds to step 600.

  In step 600, it is determined whether or not there is a master inverter device. If YES, it is determined that there is one master inverter device, and the process returns to the operation of the flowchart shown in FIG. In the case of NO, it is determined that there is no master inverter device (failure), and the process proceeds to Step 700.

  In step 700, the master inverter rank set in the activated slave inverter apparatus is confirmed, and the slave inverter apparatus having the lowest rank (for example, No. 1) is selected and transferred to the master inverter apparatus.

  In step 800, the failed master inverter device is changed to a slave inverter device.

  When the above processing is completed and a new master inverter device is set, the operation returns to the flowchart shown in FIG.

[Embodiment 2]
The operation of the second embodiment of the present invention will be described using the flowchart shown in FIG. 4 of the first embodiment.

  When an overvoltage or overcurrent abnormality occurs in the system power supply during a period in which the two master inverter devices are momentarily aligned when transferring the master function to the nth cycle master inverter device or the next cycle master inverter candidate When one or both of the master inverter devices stop supplying the output power from all the active inverter devices, and the abnormality of the system power supply is subsequently released, the processing of the flowchart shown in FIG. To start.

  In step 100 shown in FIG. 4, each selected slave inverter device confirms whether its own mode is the master inverter device or the slave inverter device, and confirms the master inverter order set in each slave inverter device.

  In step 200, it is determined whether or not there are two master inverter devices among the selected slave inverter devices. If YES, the process proceeds to step 300, and if NO, the process proceeds to step 600.

  In step 300, if the number of master inverter devices is determined to be two, the process proceeds to step 400. In the case of one unit, the process ends, and the operation returns to the operation of the flowchart shown in FIG.

  In step 400, one master inverter device is determined from the two master inverter devices based on a predetermined rule. The master inverter device determined by the predetermined rule is the next cycle master inverter candidate selected in the nth cycle, or the next cycle start candidate inverter selected in the nth cycle is unique. This is the inverter device with the lowest communication address order.

  In step 500, the remaining one master inverter device that has not been selected is turned into a slave inverter device.

  When the above processing is completed and a new master inverter device is set, the operation returns to the flowchart shown in FIG.

It is a block diagram of the power supply system of the solar cell which concerns on Embodiment 1 of this invention. FIG. 2 is a detailed diagram of a first inverter main control circuit shown in FIG. 1. It is a 1/2 flowchart explaining operation | movement of embodiment of this invention. It is a 2/2 flowchart explaining operation | movement of embodiment of this invention. It is a block diagram of the power supply system of the solar cell of a prior art. It is a switching timing diagram of a master inverter device.

Explanation of symbols

AC AC system CO1 First inverter main control circuit CO2 Second inverter main control circuit CON nth inverter main control circuit CW1 first inverter control circuit CW2 second inverter control circuit CWn nth inverter control circuit DC DC power supply (solar cell)
DS power detection unit MA main control circuit PA output power calculation circuit PC1 first inverter circuit PC2 second inverter circuit PCn nth inverter circuit PS1 first inverter device PS2 second inverter device PSn nth inverter device SW1 first switch SW2 first 2 switch SW3 3rd switch SW4 4th switch SWn-1 n-1 switch SWn nth switch TC transmission / reception circuit

Claims (4)

  A method of operating an inverter device in which a plurality of inverter devices are connected in parallel to a DC power source, and a number corresponding to the output power value of the DC power source is started from the plurality of inverter devices at predetermined intervals. The master inverter device in the nth cycle determines the number of units to be activated in the next cycle according to the output power value, and at least one of the integrated power value, the integrated activation number, and the integrated activation time of each inverter device among all the inverter devices. The next cycle start candidate inverters are selected as the next cycle start candidate inverters in ascending order of the combination value, and the next cycle master inverter candidates are selected at random from the next cycle start candidate inverters, and the (n + 1) th cycle start Sometimes, the master inverter device of the nth period starts the next master start inverter after starting the next period start candidate inverter. In the method of operating an inverter device in which a master function is transferred to a candidate and the operation is repeated thereafter, the master inverter device in the nth cycle randomly selects the next cycle start candidate inverter when selecting the next cycle master inverter candidate. An inverter ranking is given and the master inverter ranking with the smallest master inverter ranking is selected as a candidate for the next cycle master inverter, and when the master inverter device in the (n + 1) th cycle fails, the master inverter ranking is set among the inverter devices being activated. A method for operating an inverter device, wherein the smallest one is transformed into a master inverter device.   When transferring the master function from the n-th cycle master inverter device to the next cycle master inverter candidate, an overvoltage or overcurrent abnormality occurs in the system power supply during the period in which the two master inverter devices are instantaneously arranged side by side Then, one or both of the master inverter devices stop supplying the output power from all the inverter devices that are running, and when the abnormality of the system power supply is subsequently released, based on a predetermined rule 2. The inverter device according to claim 1, wherein one master inverter device is determined from the both master inverter devices, and the determined master inverter device starts supply of output power from the stopped inverter device. Driving method.   The method of operating an inverter device according to claim 2, wherein the master inverter device determined by the predetermined rule is a next cycle master inverter candidate selected in the nth cycle. 3. The operation of the inverter device according to claim 2, wherein the master inverter device determined by the predetermined rule has a minimum communication address rank unique to the next cycle start candidate inverter selected in the nth cycle. Method.

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