Sungrow Power Supply Co., Ltd.

Lei Tao

Nianan Pan

Lin Cheng

Haiyan Zou

Jie Ding

Taotao Xu

Cheng Zhang

Zhiqiang Han

Longlin Sun

Jigui Feng

Zhicheng Wang

Ai Wang

A wire connection terminal for a photovoltaic string is provided. The wire connection terminal includes: a terminal connector, a fuse and a printed circuit board (PCB). The terminal connector is connected to a positive electrode or a negative electrode of the photovoltaic string. The fuse is configured to prevent the photovoltaic string from outputting an excessive current. The PCB is configured to sample an output current and an output voltage of the photovoltaic string, communicate with an inverter, and control the photovoltaic string to disconnect from a direct current bus and output abnormal data for display when the output current and/or the output voltage of the photovoltaic string is abnormal or a system failure occurs.

Wire connection terminal for photovoltaic string

Disclosed are a medium and high voltage grid-connected power generation system, a medium and high voltage grid-connected system, and a control circuitry thereof. The voltage of the medium and high voltage power grid is collected through the control circuitry. A power grid amplitude and a power grid phase synchronization signal are obtained, and then sent to an inverter unit through a communication line.

Medium and high voltage grid-connected power generation system, medium and high voltage grid-connected system and control unit thereof

A method and device for modulating a five-level inverter, and a photovoltaic system are provided. The method includes: acquiring a voltage command value Vcmd of a phase bridge; controlling a first and a fourth switching devices to be switched on alternately when Vcmd&#x2265;VPos+Vthrs; controlling the first and a third switching devices to be switched on alternately when VPos&#x2212;Vthrs&#x2264;Vcmd&#x3c;VPos+Vthrs; controlling the fourth and the third switching devices to be switched on alternately when 0&#x2264;Vcmd&#x3c;VPos&#x2212;Vthrs; controlling the third and a fifth switching devices to be switched on alternately when &#x2212;VNeg+Vthrs&#x2264;Vcmd&#x3c;0; controlling the third and a second switching devices to be switched on alternately when &#x2212;VNeg&#x2212;Vthrs&#x2264;Vcmd&#x3c;&#x2212;VNeg+Vthrs; controlling the fifth and the second switching devices to be switched on alternately when Vcmd&#x3c;&#x2212;VNeg&#x2212;Vthrs

Method and device for modulating a five-level inverter, and photovoltaic system

A control method and apparatus for photovoltaic inverters connected in parallel at an AC side are provided and the method includes the following steps: detecting a first direct voltage of the first inverter and a second direct voltage of the second inverter; obtaining a difference between the first direct voltage and the second direct voltage; and adjusting the direct voltages of the inverters to control the difference to be within a predetermined range and control a common-mode voltage in the common-mode loop to be within a predetermined common-mode voltage range.

Control method and system for photovoltaic inverters whose AC sides are connected in parallel

A method and device for monitoring and suppressing a resonance are provided, which are applied to a grid-connected generation system. A current sample voltage of a preset sample point of the grid-connected generation system is monitored in a real time manner; amplitudes of harmonics of the current sample voltage are acquired using a preset algorithm; it is verified whether a resonance occurs in the grid-connected generation system currently based on the acquired amplitudes of the harmonics; in a case that the resonance occurs in the grid-connected generation system, current corrections of parameters of inverters in the grid-connected generation system are acquired according to a preset rule and the parameters of the inverters are adjusted using the current corrections and a selected resonance suppressing algorithm.

Method and device for monitoring and suppressing resonance

A charging and discharging system, a charging and discharging method, and a photovoltaic power generation system are provided. The charging and discharging system includes: a unidirectional converter, a unidirectional switch, an energy storage device and a controller; where an input terminal of the unidirectional converter is connected to an output terminal of a photovoltaic device of a photovoltaic power generation system to which the charging and discharging system is applied, and an output terminal of the unidirectional converter is connected to an input terminal of the energy storage device; the unidirectional switch is connected between an output terminal of the energy storage device and an input terminal of a bidirectional inverter of the photovoltaic power generation system to which the charging and discharging system is applied; the controller is connected to the unidirectional converter, the unidirectional switch, the energy storage device and the bidirectional inverter.

Charging and discharging system and method, and photovoltaic power generation system

A method and device for switching an operation mode of a five-level inverter are provided. The method includes: determining a first three-level operation mode as a three-level operation mode to be switched to from a five-level operation mode in a case that a PV input voltage is higher than a bridge line-line voltage command value; switching, after the operation mode is switched to the first three-level operation mode, the operation mode from the first three-level operation mode to a second three-level operation mode, in a case that a junction temperature of a switching device operating in the first three-level operation mode exceeds a first preset value; and switching the operation mode from the second three-level operation mode to the first three-level operation mode in a case that the junction temperature of a switching device operating in the second three-level operation mode exceeds a second preset value.

Method and device for switching operation mode of a five-level inverter

Provided are a parallel inverter system, and a shutdown control method and a shutdown control device for the parallel inverter system. A shutdown instruction is determined and responded according to a level of the shutdown instruction. The shutdown instruction is determined to be an emergency shutdown instruction under certain emergency shutdown conditions, and a driving signal for the power switch devices of the inverter apparatus is needed to be instantly locked out. The shutdown instruction is determined to be a normal shutdown instruction under non-emergency shutdown conditions, a switch-off signal is transmitted to alternating-current switches connected to the inverter apparatus to be shut down, states of the alternating-current switches connected to the inverter apparatus to be shut down are detected, the driving signal for the power switch devices of the inverter apparatus to be shut down is instantly locked out in a case that the alternating-current switches are switched off.

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Anhui, China

Lei Tao