Sungrow Power Supply Co., Ltd.

Hefei Clt Microelectronics Co. Ltd

Lin Cheng

Nianan Pan

Lei Tao

Longlin Sun

Zhicheng Wang

Houlai Geng

Jie Ding

Jigui Feng

Menglin Cao

Xing Li

Cheng Liang

Zeguo Liu

Jingyi Yuan

Feng Wu

Guohua Xiang

The present application discloses a multi-channel grid-connected power generation system and a control method therefor, which lowers the system cost while reducing no-load losses of all step-up transformers. Multi-channel energy conversion devices in the system are each connected in parallel, by means of a step-up transformer, to the same collector line, one end of the collector line is connected to the grid by means of a switch device, and the on-off switching of the switch device is controlled by a control unit. The control unit sends a switch-off command to the switch device when same has determined that all of the energy conversion devices have entered a non-operating state. In the off state of the switch device, at least one energy conversion device, when meeting a start-up condition, starts to operate as a voltage source, and establishes an alternating-current voltage, so that the phase difference and amplitude difference of voltages at two ends of the switch device are both stable within an allowable error range. Then, the control unit sends a switch-on command to the switch device, and the other energy conversion devices start to operate as a current source to transfer energy to the grid.

Multi-channel grid-connected power generation system and control method therefor

Multiphase series capacitor DC-DC converters are provided, including: a power stage circuit configured to convert an input DC voltage into a stable DC voltage required by a load, where the power stage circuit includes inductors of two or more phases, and there is a phase difference with a preset interval between inductor currents of phases for alternately charging the load in sequence, and a bidirectional switch is provided between inductors of every two adjacent phases, where when the bidirectional switch is turned on, the inductors of the corresponding two phases charge the load simultaneously; and a load transient response circuit configured to, when a load transient positive step occurs, control one or more bidirectional switches to be turned on to make inductors of two or more corresponding phases charge the load simultaneously. Control methods of such converters are also provided, which can realize fast response to load transient changes.

Multiphase series capacitor DC-DC converter and control method

An inverter circuit control method and a device thereof are provided. In the control method, after determining a DC bus voltage and an output leakage current of a target inverter circuit, a modulation harmonic wave to be injected into a SPWM signal is adjusted according to the DC bus voltage or the output leakage current if it is determined according to the DC bus voltage that the target inverter circuit satisfies a preset modulation condition, such that total harmonic distortion of a current of the target inverter circuit is within a preset range. The DC bus voltage and the output leakage current of the target inverter circuit are used as references for adjusting the modulation harmonic wave, ensuring total harmonic distortion of the current of the target inverter circuit to be within a preset range.

Inverter circuit control method and device thereof

A method, a device, and a system for protecting parallel-connected topology units are provided. A target signal transmitted via the signal synchronization line is obtained, and the target signal is sent to other controllers based on a type of the target signal. If the target signal is a carrier synchronization signal, the current power module is controlled to perform carrier synchronization and to be in a working mode. If the target signal is a power module fault signal, the current power module is controlled to be in a shutdown mode. The signal synchronization lines between the parallel-connected topology units are shared in a time-sharing manner, where the carrier synchronization signal is transmitted if the power module works normally, and the power module fault signal is transmitted if the power module is faulty. The topology units monitor the transmitted target signal in real time for fast synchronous protection.

Method, device and system for protecting parallel-connected topology units

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 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

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

Lin Cheng