Abstract: The application provides a photovoltaic inverter system, an automatic locating method of RSDs and a fault control method thereof. The automatic locating method comprises turning off all RSDs and sampling a voltage of an output end of each RSD as a first voltage before an inverter operates; turning on any one of the RSDs and sampling a voltage of the output end of each RSD as a second voltage, determining all RSDs in a photovoltaic module string to which the RSD in a turned-on state belongs according to the first voltage and the second voltage, and repeating the above control method for any one of the RSDs outside the photovoltaic module string to which the determined RSDs belong until corresponding connection relations between all RSDs and all photovoltaic module strings are determined.

Abstract: An islanding detection system and method for multiple inverters operating in parallel, wherein the multiple inverters at least comprises a first inverter and a second inverter connected in parallel. The islanding detection system comprises a current detection circuit arranged on a grid side or an AC side of the second inverter; and a controller connected to the current detection circuit and the first inverter. The controller determines whether to perform distributed islanding detection or centralized islanding detection on the first inverter and the second inverter according to a grid voltage signal and a current detection signal of the current detection circuit. By recognizing the islanding detection mode of the second inverter, matching it with typical islanding detection modes preset in a library, and determining to perform a distributed or centralized islanding detection according to matching results, the application improves the success ratio of islanding detection.

Abstract: The application discloses an automatic transfer switch and a power supply system. The automatic transfer switch includes: a first switch unit having a first end connected to a first device through a converter port, and a second end electrically connected to a power grid through a power grid port; a second switch unit having a first end connected to a second device through an electric vehicle port and a charging/discharging circuit unit, and a second end electrically connected to the second end of the first switch unit; a third switch unit, having a first end electrically connected to the power grid through the power grid port, and a second end electrically connected to a load through a load port; a sampling unit; and a control unit connected to the sampling unit.

Abstract: The application provides a photovoltaic inverter system, an automatic locating method of RSDs and a fault control method thereof. The automatic locating method comprises turning off all RSDs and sampling a voltage of an output end of each RSD as a first voltage before an inverter operates; turning on any one of the RSDs and sampling a voltage of the output end of each RSD as a second voltage, determining all RSDs in a photovoltaic module string to which the RSD in a turned-on state belongs according to the first voltage and the second voltage, and repeating the above control method for any one of the RSDs outside the photovoltaic module string to which the determined RSDs belong until corresponding connection relations between all RSDs and all photovoltaic module strings are determined.

Abstract: A photovoltaic energy storage system and a control method for the photovoltaic energy storage system are provided. The photovoltaic energy storage system includes an energy storage unit, a photovoltaic array assembly, an inverter and a rapid shutdown switch. The inverter is electrically coupled to the energy storage unit and the photovoltaic array assembly. The rapid shutdown switch is electrically coupled to the inverter, a power grid and a load. A detecting and controlling circuit of the inverter detects at least two of a first voltage, a second voltage and a third voltage, and determines whether the rapid shutdown switch is turned off according to the detected voltages and a reference value. When it is determined that the rapid shutdown switch is turned off, a connection between the inverter and the energy storage unit and a connection between the inverter and the photovoltaic array assembly are cut off.

Abstract: An islanding detection system and method for multiple inverters operating in parallel, wherein the multiple inverters at least comprises a first inverter and a second inverter connected in parallel. The islanding detection system comprises a current detection circuit arranged on a grid side or an AC side of the second inverter; and a controller connected to the current detection circuit and the first inverter. The controller determines whether to perform distributed islanding detection or centralized islanding detection on the first inverter and the second inverter according to a grid voltage signal and a current detection signal of the current detection circuit. By recognizing the islanding detection mode of the second inverter, matching it with typical islanding detection modes preset in a library, and determining to perform a distributed or centralized islanding detection according to matching results, the application improves the success ratio of islanding detection.

Abstract: The invention discloses an inverter and a soft-start method for the same. The inverter is electrically connected between a DC power supply and a grid and includes a main power circuit electrically coupled to the grid through a relay, a filter, the relay, and a controller electrically connected with the main power circuit and the relay, respectively. The soft-start method includes: sampling a grid voltage of the grid; calculating an output voltage of the controller, and calculating a virtual current based on the output voltage of the controller, the grid voltage and a virtual impedance; and performing current closed-loop control by taking the virtual current as a feedback signal and sending a relay control signal to turn on the relay when a steady state is reached. The invention enables the soft start of the inverter without increasing any hardware circuit, such as a starting resistor, or the like.

Abstract: A method for identifying type of a grid automatically and an inverter device thereof are provided. The inverter device comprises a power line L1, a power line L2, a neutral line N and a ground line electrically connectable to a first power line, a second power line, a neutral line and a ground line of the grid, respectively. The method comprises: sampling at least two of voltages between L1 and L2, between L1 to N and between L2 to N when the two neutral lines are connected, and identifying the type of the grid based on the sampling result; and sampling the voltage between L1 and L2 when the two neutral lines are not connected, sampling at least one of a voltage between L1 and GND and between L2 and GND with cooperation of a grid-connected switching unit, and identifying the type of the grid based on the sampling results.

Abstract: The invention discloses an inverter and a soft-start method for the same. The inverter is electrically connected between a DC power supply and a grid and includes a main power circuit electrically coupled to the grid through a relay, a filter, the relay, and a controller electrically connected with the main power circuit and the relay, respectively. The soft-start method includes: sampling a grid voltage of the grid; calculating an output voltage of the controller, and calculating a virtual current based on the output voltage of the controller, the grid voltage and a virtual impedance; and performing current closed-loop control by taking the virtual current as a feedback signal and sending a relay control signal to turn on the relay when a steady state is reached. The invention enables the soft start of the inverter without increasing any hardware circuit, such as a starting resistor, or the like.

Abstract: A hysteresis control method for inverter and an inverter based on hysteresis control are disclosed. The inverter is electrically connected to a power grid, and the method includes: Step S1, sampling a grid voltage Vg(z) and an output current Ig(z) of the inverter; Step S2, calculating a present period hysteresis bandwidth H(z) based on the grid voltage Vg(z) sampled in step S1; Step S3, predicting a next period hysteresis bandwidth H(z+1); Step S4, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S3, to obtain a final hysteresis bandwidth Hout(z); and Step S5, controlling an output driving signal according to the output current Ig(z) of the inverter and the final hysteresis bandwidth Hout(z) to control the operation of the inverter.

Abstract: A method of upgrading inverter software comprises: embedding a software upgrade package for software to be upgraded into an application package, and uploading the application package to a server; obtaining the application package from the server through a terminal and sending the application package to an inverter, wherein the terminal and the inverter are connected through a wireless communication; in an operating cycle, determining by the inverter whether current time is within a predetermined time window, and if the current time is within the predetermined time window, performing a next operation, and if the current time is not within the predetermined time window, entering a next operating cycle; obtaining version information of the software of the inverter to be upgraded; and if the version information of the software to be upgraded is lower than that of the application package, performing an upgrade operation.

Abstract: A method for identifying type of a grid automatically and an inverter device thereof are provided. The inverter device comprises a power line L1, a power line L2, a neutral line N and a ground line electrically connectable to a first power line, a second power line, a neutral line and a ground line of the grid, respectively. The method comprises: sampling at least two of voltages between L1 and L2, between L1 to N and between L2 to N when the two neutral lines are connected, and identifying the type of the grid based on the sampling result; and sampling the voltage between L1 and L2 when the two neutral lines are not connected, sampling at least one of a voltage between L1 and GND and between L2 and GND with cooperation of a grid-connected switching unit, and identifying the type of the grid based on the sampling results.

Abstract: A hysteresis control method for inverter and an inverter based on hysteresis control are disclosed. The inverter is electrically connected to a power grid, and the method includes: Step S1, sampling a grid voltage Vg(z) and an output current Ig(z) of the inverter; Step S2, calculating a present period hysteresis bandwidth H(z) based on the grid voltage Vg(z) sampled in step S1; Step S3, predicting a next period hysteresis bandwidth H(z+1); Step S4, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S3, to obtain a final hysteresis bandwidth Hout(z); and Step S5, controlling an output driving signal according to the output current Ig(z) of the inverter and the final hysteresis bandwidth Hout(z) to control the operation of the inverter.

Abstract: A method of upgrading inverter software comprises: embedding a software upgrade package for software to be upgraded into an application package and uploading the application package to a server; obtaining the application package from the server through a terminal; obtaining version information of the software from an inverter to be upgraded through the terminal, wherein the terminal and the inverter are connected through a wireless communication; comparing the version information of the software from the inverter to be upgraded with version information of the software upgrade package in the application upgrade package through the terminal; if the comparison result is that the version information of the software to be upgraded is lower than the version information of the software upgrade package in the application upgrade package, sending the software upgrade package to the inverter through the terminal for the inverter to perform an upgrade operation.

Abstract: Method, apparatus and system for crosstalk suppression of power line communication are provided. The method includes: receiving a joining request message; judging a matching state of the communication terminal based on a history matching record and communication terminal identifier, if matching state of the communication terminal is unmatched: sending a joining response message to the communication terminal; receiving an acknowledgment request message sent by the communication terminal after switch of the communication terminal is turned on; detecting voltage on power line between the communication terminal and an inverter corresponding to the power line communication transmitter, if voltage is within preset voltage range, sending an acknowledgment response message to the communication terminal; storing communication terminal identifier in history matching record and storing matching state of the communication terminal as successfully-matched.

Abstract: Method, apparatus and system for crosstalk suppression of power line communication are provided. The method includes: receiving a joining request message; judging a matching state of the communication terminal based on a history matching record and communication terminal identifier, if matching state of the communication terminal is unmatched: sending a joining response message to the communication terminal; receiving an acknowledgment request message sent by the communication terminal after switch of the communication terminal is turned on; detecting voltage on power line between the communication terminal and an inverter corresponding to the power line communication transmitter, if voltage is within preset voltage range, sending an acknowledgment response message to the communication terminal; storing communication terminal identifier in history matching record and storing matching state of the communication terminal as successfully-matched.

Abstract: The present disclosure provides a method and a device for arc fault detection for a photovoltaic inverter, and a photovoltaic inverter using the same. The method includes: acquiring current signals at a DC side of the photovoltaic inverter; obtaining frequency spectral characteristics of the current signal according to the current signal; judging whether the frequency spectral characteristics of the current signal have a frequency spectral characteristic of an arc; and if the frequency spectral characteristics of the current signal have a frequency spectral characteristic of an arc, shutting down the photovoltaic inverter, acquiring respectively a first input voltage when the photovoltaic inverter is shut down and a second input voltage after a predetermined time period after the shutdown, calculating a voltage drop from the first input voltage to the second input voltage, and judging whether an arc fault occurs according to the voltage drop.

Abstract: The present disclosure provides a method and a device for arc fault detection for a photovoltaic inverter, and a photovoltaic inverter using the same. The method includes: acquiring current signals at a DC side of the photovoltaic inverter; obtaining frequency spectral characteristics of the current signal according to the current signal; judging whether the frequency spectral characteristics of the current signal have a frequency spectral characteristic of an arc; and if the frequency spectral characteristics of the current signal have a frequency spectral characteristic of an arc, shutting down the photovoltaic inverter, acquiring respectively a first input voltage when the photovoltaic inverter is shut down and a second input voltage after a predetermined time period after the shutdown, calculating a voltage drop from the first input voltage to the second input voltage, and judging whether an arc fault occurs according to the voltage drop.