Delta Electronics (shanghai) Co., Ltd

Delta Electronics, Inc.

Xuancai Zhu

Bingwen Weng

Feidong Xu

Jinfa Zhang

Qin Wang

Wei Zhao

Jianming Chen

Qikang Wei

Yuxi Wang

Chengjun He

Yanlong Li

Bin Wang

Shen Chen

Kerou Wang

Jiangtao Yan

Weiyi Zheng

Zhiying Zhao

Yafeng Liao

Jiao Zhang

The present application provides a control method, an auxiliary power supply of a photovoltaic inverter, and a photovoltaic power generation system. The auxiliary power supply includes a rectifier circuit and a conversion circuit with at least one output terminal. The conversion circuit includes a voltage determining unit and a power determining unit. The conversion circuit is coupled to an output terminal of the rectifier circuit, and is configured to convert direct current power into at least one auxiliary voltage. The power determining unit and the voltage determining unit are coupled to an input terminal of the inverter circuit or an input terminal of the photovoltaic inverter, which are configured to obtain output power and an output voltage of the solar panel, respectively. When the output voltage is greater than the start-up voltage and the output power is greater than the start-up power, the auxiliary power supply starts.

Control method, auxiliary power supply of photovoltaic inverter and photovoltaic power generation system

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.

Photovoltaic inverter system, automatic locating method of rapid shutdown devices and fault control method thereof

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.

Islanding detection system and method

The disclosure discloses a photovoltaic power optimization system, comprising: a plurality of photovoltaic panels; a photovoltaic optimizing module array comprising a plurality of photovoltaic optimizing modules connected in series, each of the photovoltaic optimizing modules being electrically connected to at least one of the photovoltaic panels; an inverter electrically connected to an output terminals of the photovoltaic optimizing module array for converting a DC power into an AC power; and a data center unit communicates wirelessly with at least one of the photovoltaic optimizing modules, and also communicates with the inverter via power line.

Photovoltaic power optimization system

The present disclosure provides a rapid shutdown device for a photovoltaic system, which is connected between a photovoltaic power generation module and a photovoltaic inverter and comprises an input port and an output port. The rapid shutdown device further comprises: a first switch and a second switch; a third switch and a fourth switch; a controller coupled to control terminals of the first switch, the third switch, and the fourth switch, and configured to control on and off of the first switch, the third switch, and the fourth switch, so that the rapid shutdown device operates in a normal state, a bypass state or a shutdown state.

Rapid shutdown device for photovoltaic system and control method thereof and protection system

It is disclosed an insulation impedance detection circuit and detection method of a photovoltaic inverter system. The photovoltaic inverter system includes one or more input circuits and an inverter circuit, each of the input circuit electrically coupled to the inverter circuit through a positive bus and a negative bus, with a first equivalent impedance Rbetween the positive bus and a protective earth point and a second equivalent impedance Rbetween the negative bus and the protective earth point. The detection circuit includes: a bus voltage sampling circuit coupled to the positive bus and the negative bus for generating a first bus voltage and a second bus voltage; a protective earth voltage sampling circuit coupled to the protective earth point for generating a first protective earth voltage and a second protective earth voltage; and a controller for calculating an equivalent insulation impedance.

Insulation impedance detection circuit and insulation impedance detection method of photovoltaic inverter system

A rapid shutdown device and a photovoltaic system are provided. The photovoltaic system includes an inverter and multiple serially-connected photovoltaic elements. The rapid shutdown device includes a switching circuit, a control circuit, a communication circuit and an auxiliary power circuit. The switching circuit includes a first switch and a second switch. A first terminal of the first switch is electrically connected with the positive terminal of a first photovoltaic element. A second terminal of the first switch is electrically connected with the negative terminal of a second photovoltaic element. A first terminal of the second switch is electrically connected with the negative terminal of the first photovoltaic element. The communication circuit receives a command signal from the inverter and transmits it to the control circuit. The control circuit controls the first switch and the second switch to turn on or turn off according to the command signal.

Rapid shutdown device and photovoltaic system

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.

Inverter and soft-start method for the same

The invention discloses a photovoltaic inverter system and a method for controlling the same. The photovoltaic inverter system comprises: an optimizing module string and an inverter, wherein the optimizing module string comprises a plurality of optimizing modules each having an input port coupled to at least one photovoltaic module, output ports of the plurality of optimizing modules are connected in series, each of the optimizing modules comprises a control unit, an input port of the inverter is coupled to an output port of the optimizing module string, the inverter comprises an auxiliary detection module for auxiliary detecting an output current of the optimizing module string, and the control unit controls an output voltage of the optimizing module string based on the output current of the optimizing module string, such that the output voltage satisfies a start-up condition of the inverter.

Photovoltaic inverter system and method for controlling the same

A method for identifying type of a grid automatically and an inverter device thereof are provided. The inverter device comprises a power line L, a power line L, 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 Land L, between Lto N and between Lto 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 Land Lwhen the two neutral lines are not connected, sampling at least one of a voltage between Land GND and between Land GND with cooperation of a grid-connected switching unit, and identifying the type of the grid based on the sampling results.

Method for identifying the type of a grid automatically and inverter device thereof

The invention discloses a photovoltaic power generation system and a method for controlling the same. The photovoltaic power generation system comprises: an string of optimizing modules and an inverter, the string of optimizing modules comprises a plurality of optimizing modules each having an input port coupled to at least one photovoltaic module, output ports of the plurality of optimizing modules are connected in series, each of the optimizing modules comprises a control unit, an input port of the inverter is coupled to an output port of the string of optimizing modules, and the inverter comprises an auxiliary detection module for auxiliary detecting an output current of the string of optimizing modules, and the control unit controls an output voltage of the string of optimizing modules based on the output current of the string of optimizing modules, such that the output voltage satisfies a start-up condition of the inverter.

Photovoltaic power generation system and method for controlling the same

The present disclosure provides an optimizer for a photovoltaic system, a control method for an optimizer, and an optimizer parallel arrangement thereof. In the method, a DC bus voltage output by the optimizer is acquired; and the optimizer is controlled to switch among an MPPT mode, a limited power mode and a fast shutdown mode based on the DC bus voltage.

Optimizer, control method and parallel arrangement for photovoltaic system

An inverting apparatus comprises: a DC port; an AC port; five switches; a first capacitor coupled between the first terminal of the second switch and the second terminal of the fourth switch; and a free-wheeling element coupled between the second terminal of the third switch and the second terminal of the fifth switch; wherein the five switches are controlled so that the device can switch among a plurality of operating modes and transmit active or reactive power to a power grid.

Non-isolated inverting apparatus, control method thereof and photovoltaic system having the same

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 S, sampling a grid voltage V(z) and an output current I(z) of the inverter; Step S, calculating a present period hysteresis bandwidth H(z) based on the grid voltage V(z) sampled in step S; Step S, predicting a next period hysteresis bandwidth H(z+1); Step S, correcting the present period hysteresis bandwidth H(z) based on the next period hysteresis bandwidth H(z+1) obtained in step S, to obtain a final hysteresis bandwidth H(z); and Step S, controlling an output driving signal according to the output current I(z) of the inverter and the final hysteresis bandwidth H(z) to control the operation of the inverter.

Hysteresis control method for inverter and an inverter with hysteresis control

A detection circuit includes: a first switch, a second switch, a first detection resistor and a second detection resistor, wherein the first switch and the first detection resistor are coupled in series to form a first branch, a first end of the first branch is electrically connected with a positive bus of the photovoltaic inverter and a second end of the first branch is electrically connected with a ground; and the second switch and the second detection resistor are coupled in series to form a second branch, a first end of the second branch is electrically connected with a negative bus of the photovoltaic inverter and a second end of the second branch is electrically connected with the ground.

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Shanghai, China

Xuancai Zhu