Aoran Xu

Research and Design for a New Storage Type Converter

In the micro-grid, power storage converter is played as a interface between the battery pack and grid electricity storage device, to achieve a two- way exchange of energy. In this paper, the research and development of power storage converter can realize multiple sets of independent control of the battery, flexible configuration of the system capacity and flexible cutting of the battery pack. Structural design uses multi-level topology. It contains 15 non-isolated half-bridge parallel bi-directional DC / DC converter. Control strategy designed to be grid inverter adopts SVPWM control technology. DC / DC converter designed to improve the droop control strategy based on environmental design. The high-power energy storage converter product this paper designed have completed the charge and discharge related droop control and Full power grid experiment.

Crowbar circuit in wind power grid low voltage ride through

The principle of DFIG wind power generation system is analyzed and the mathematic model is developed. The function of the active Crowbar in LVRT is studied and the parameters of the active Crowbar are given. The simulation result shows that the DFIG system with active crowbar can protect converter against overvoltage and over current. Finally, main power circuit and driving circuit of the active Crowbar is designed. A VSG (Voltage Sag Generation) based on resistor is built. The corresponding experiment is done on the 90kWDFIG experimental platform. The LVRT scheme based on the active Crowbar is studied through experimentation. The experiment result shows that Crowbar is necessary for improving LVRT capability of DFIG wind power generation system and LVRT scheme based on the active Crowbar is effective.