(US20180224816) PHOTOVOLTAIC INVERTER HAVING AN IMPROVED COMMUNICATION ARRANGEMENT WITH A REMOTE COMPUTERISED SYSTEM

The present invention relates to the field of photovoltaic plants for electric power generation.
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As is known, photovoltaic inverters are power electronic apparatuses widely used in photovoltaic electric power generation plants for performing power conversion of DC power received by one or more photovoltaic panels into AC power to be delivered to local electric loads and/or to an electric power distribution grid, according to the needs.
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In many photovoltaic plants, performances of installed photovoltaic inverters are continuously monitored to collect on-the-field data (e.g. including measurement data and other useful data related to the operation of the photovoltaic panels or inverters) to be analyzed and aggregated to provide structured information related to operation of said installations. To this aim, the photovoltaic inverters are typically linked through wired or wireless wide-band communication lines to a common gateway (e.g. a data logger). This latter is linked through further wired or wireless wide-band communication lines to a remote communication system (e.g. a remote server portal).
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In order to solve the above-mentioned problems, the photovoltaic inverters are often configured to locally store given on-the-field data of interest when a failure in communication with the remote computerised system occurs. Said on-the-field data are then transmitted to the remote computerised system as soon as the communication with this latter is restored.
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For the above illustrated reasons, in the state of the art, it is quite felt the need for simple and inexpensive solutions that ensure a given level of continuity in the monitoring activity of installed photovoltaic inverters and, at the same time, that allow collecting useful information for reacting to possible failures of the wide-band communication network linking said photovoltaic inverters to a remote computerised system.
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The photovoltaic inverter 1 has a DC port 11 intended to be electrically connected with DC electric lines (not shown) transmitting DC electric power generated by the photovoltaic panels of the photovoltaic plant and an AC port 12 intended to be electrically connected with AC electric lines (not shown) transmitting AC electric power to local electric loads and/or to an electric power distribution grid (not shown).
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The main communication port 21 may be of the wired type, for example of the RS485, CAN, Ethernet type or the like, or of the wireless type, for example IEEE 802.15.4, ZigBee, Bluetooth, Wi-Fi, GSM, GRPS, UMTS, 3G, 4G, 5G type or the like, and it may employ a variety of communication protocols, such as TCP/IP, MODBUS, or other open or proprietary communication protocols.
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The main communication channel 35 may be of the wired type, for example of the RS485, CAN, Ethernet type or the like, or of the wireless type, for example IEEE 802.15.4, ZigBee, Bluetooth, Wi-Fi, GSM, GRPS, UMTS, 3G, 4G, 5G type or the like, and it may employ a variety of communication protocols, such as TCP/IP, MODBUS, or other open or proprietary communication protocols.
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As an example, the first portion 351 of the communication channel 35 may be of the RS485, CAN, Ethernet, IEEE 802.15.4 RF, ZigBee, Bluetooth type whereas the second portion 352 of the communication channel 35 may be of the Wi-Fi, GSM, GRPS, UMTS, 3G, 4G, 5G type. The portions 351, 352 of the main communication channel 35 may also employ different communication protocols.
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In this case, the remote computerized system may employ a single computerized unit or of several computerized units connectable to the Internet and interacting one with another, for example to implement a cloud computing architecture. As an example, such computerized units may be equipped with operating systems for devices with “server” type functionalities, for example Windows Server, Windows Azure, Mac OS Server or the like.
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The auxiliary communication port 22 is controlled by the control unit 2, which can suitably activate or deactivate it according to the needs. Obviously, when the auxiliary communication port 22 is deactivated for some reasons the communication with external devices is prevented. The auxiliary communication port 22 may be of wired or wireless type, according to the needs.
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Preferably, in operation, the control unit 2 activates the auxiliary communication port 22 on a periodic time-base to transmit one or more first data-sets D1, which include first predefined information related the operation status of said inverter or of said plant, through said auxiliary communication port.
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As an example, the control unit 2 may activate the auxiliary communication port 22 once a day to transmit basic information related the operation status of said inverter or of said plant, such as information related to the overall energy produced by the photovoltaic plant and information on the current functional state of said plant. Other information may include alarm messages, warning messages, event messages, measurement data, and the like.
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Preferably, if it does not receive instructions within the predefined time interval T W1, the control unit 2 deactivates the auxiliary communication port 22. In this case, preferably, the control unit 2 will again activate the auxiliary communication port 22, according to the predefined schedule time-base mentioned above.
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As an example, in response to the instructions received within the predefined time interval T W1, the control unit 2 may immediately transmit the second data-sets D 2 through the auxiliary communication port 22. After the transmission of the second data-sets D 2 the control unit 2 may wait for further instructions or deactivate the communication port 2 waiting for the next activation that will be carried out according to the predefined schedule time-base mentioned above.
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The second data-sets D 2 may include further information related to the power conversion process, for example information related to active and reactive power set-points of the photovoltaic inverter, the operative parameters or the photovoltaic inverter, alarms related to the photovoltaic inverter or the photovoltaic plant, and the like. Other information may include data related to the residual available traffic through mobile communication channels (3G, 4G, 5G, and so on) in case of prepaid services.
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The second data-sets D 2 may further include information related to the operative status of the control unit 2, such as information related to absence of connectivity through the main communication port 21, unavailability of the main communication channel 35, changes in the communication parameters with the main communication channel 35, amount of stored on-the field data in case of absence of connectivity through the main communication port 21, and the like.
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As an example, in response to the instructions received within the predefined time interval T W1, the control unit 2 may immediately deactivate the communication port 2 and then again activate the communication port 2 at the requested time to receive further instructions from the computerised system30 or 40 (call-back functionality).
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As an example, in response to the instructions received within the predefined time interval T W1, the control unit 2 may activate, deactivate, lock or unlock the main communication port 21 or provide specific control signals to the power conversion section 13 of the photovoltaic inverter to set-up the operation of said power conversion section.
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For each photovoltaic inverter, the computerised platform 100 comprises a narrow-band auxiliary communication port 22 of said inverter and a narrow-band auxiliary communication channel 45 linking the auxiliary communication port 22 of the photovoltaic inverters 1 and the remote computerised system30.
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The auxiliary communication port 22 may be used as an emergency communication port to be used to acquire some information related to the operative status of the photovoltaic inverter, more related to the operative status of the main communication port 21 and of the main communication channel 35 linked thereto, when the photovoltaic inverter 1 cannot communicate, for same reasons, with the computerized system 30 through the main communication port 21.
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This feature allows collecting information to properly react to a fault in the main communication network linking the photovoltaic inverter 1 with the computerized system 30. The auxiliary communication port 22 may also be used for implementing some specific functionalities in managing the operation of the photovoltaic inverter, such as controlling the access to the photovoltaic inverter 1 through the main communication port 21.
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Claims |
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1. A photovoltaic inverter for a photovoltaic electric power generation plant, said photovoltaic inverter comprising:
a control unit for controlling the operation of said photovoltaic inverter and a main communication port for communication with a remote computerised system through a main communication channel which comprises an auxiliary communication port for communication with a remote computerised system through an auxiliary communication channel, said auxiliary communication port having a narrow band so that said control unit can transmit or receive only small-size data-sets through said auxiliary communication port.
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2. The photovoltaic inverter, according to claim 1, wherein said control unit is configured to transmit small-size data-sets including information related the operation status of said inverter or of said plant through said auxiliary communication port.
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3. The photovoltaic inverter, according to claim 1, wherein said control unit is configured to normally maintain deactivated said auxiliary communication port and to activate said auxiliary communication port for finite time intervals only.
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4. The photovoltaic inverter, according to claim 3, wherein said control unit is configured to activate said auxiliary communication port on a periodic time-base to transmit one or more first data-sets, which include first predefined information related the operation status of said inverter or of said plant, through said auxiliary communication port.
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5. The photovoltaic inverter, according to claim 4, wherein said control unit is configured to maintain said auxiliary communication port active for a predefined time interval (T W1) after the transmission of said one or more first data-sets.
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6. The photovoltaic inverter, according to claim 5, wherein said control unit is configured to deactivate said auxiliary communication port if no instructions are received within said predefined time interval (T W1).
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7. The photovoltaic inverter, according to claim 5, wherein said control unit is configured to carry out one or more requested tasks in response to instructions received within said predefined time interval (T W1).
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8. The photovoltaic inverter, according to claim 7, wherein said requested tasks include the immediate or delayed transmission of one or more second data-sets, which include second information related the operation status of said inverter or of said plant, through said auxiliary communication port.
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9. The photovoltaic inverter, according to claim 7, wherein said requested tasks include the activation of said auxiliary communication port at a requested time and for a further predefined time interval (T W2) to receive further instructions through said auxiliary communication port.
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10. The photovoltaic inverter, according to claim 7, wherein said requested tasks include control tasks related to the management of the operation of said control unit and/or said inverter.
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11. The photovoltaic inverter, according to claim 1, wherein said main communication port is a wide-band communication port.
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12. The photovoltaic inverter, according to claim 1, wherein said auxiliary communication port is an ultra-narrow-band communication port.
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13. A computerised platform for monitoring the operation of one or more photovoltaic inverters ( 1 A, 1 N), according to claim 1, wherein it comprises:
a remote computerised system;
one or more control units comprised in said photovoltaic inverters to control the operation of said photovoltaic inverters;
for each photovoltaic inverter, a main communication port of said photovoltaic inverter and a main communication channel linking said main communication port and said remote computerised system;
for each photovoltaic inverter, a narrow-band auxiliary communication port of said photovoltaic inverter and a narrow-band auxiliary communication channel linking said auxiliary communication port and said remote computerised system.
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14. The photovoltaic inverter, according to claim 2, wherein said control unit is configured to normally maintain deactivated said auxiliary communication port and to activate said auxiliary communication port for finite time intervals only.
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15. The photovoltaic inverter, according to claim 14, wherein said control unit is configured to activate said auxiliary communication port on a periodic time-base to transmit one or more first data-sets, which include first predefined information related the operation status of said inverter or of said plant, through said auxiliary communication port.
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16. The photovoltaic inverter, according to claim 14, wherein said control unit is configured to maintain said auxiliary communication port active for a predefined time interval (T W1) after the transmission of said one or more first data-sets (D 1).
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17. The photovoltaic inverter, according to claim 16, wherein said control unit is configured to deactivate said auxiliary communication port if no instructions are received within said predefined time interval (T W1).
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18. The photovoltaic inverter, according to claim 16, wherein said control unit is configured to carry out one or more requested tasks in response to instructions received within said predefined time interval (T W1).
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19. The photovoltaic inverter, according to claim 18, wherein said requested tasks include the immediate or delayed transmission of one or more second data-sets (D 2), which include second information related the operation status of said inverter or of said plant, through said auxiliary communication port.
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20. The photovoltaic inverter, according to claim 8, wherein said requested tasks include the activation of said auxiliary communication port at a requested time and for a further predefined time interval (T W2) to receive further instructions through said auxiliary communication port.
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