High and Low Voltage Ride Through Technology Research Review of Energy Storage Inverter
This paper briefly introduces the energy storage inverter. The domestic and foreign standards of photovoltaic power generation system and wind power generation system are respectively explained. This paper introduces several key technologies of photovoltaic generation system and wind power generation system, such as low voltage ride through and high voltage ride through, it points out the problems of high and low voltage ride through technology of energy storage inverter. Introduction At present, more and more countries, including China, grid connected inverters are required to keep running on the grid when the grid voltage drops to 20% of normal value or even 0. Chinese State Grid Corporation in 2009 also introduced "wind farm access power grid technical requirements" and "photovoltaic power plant access grid technical requirements", which provide our own low voltage ride through technical requirements. Energy storage inverter also needs to have the function of low voltage through. At the same time, because of its stable DC side, we will be able to better achieve LVRT function. Compared with the low voltage ride through technology, the high voltage ride through technology is not paid much attention by the researchers in the early stage of the low voltage ride through technology. In recent years, people have gradually noticed the importance of high voltage through technology, launched a series of studies. Many countries begin to pay attention to the high voltage through technology of wind turbine, combine the high, low voltage through of the wind turbine into the fault crossing, and began to develop the corresponding grid guideline. Therefore, the energy storage inverter also needs to have the function of high voltage through. Energy Storage Inverter Introduction Energy storage inverter is a kind of the three-phase converter, being suitable for smart grid construction, applying in the energy storage link, basing on space voltage vector pulse width modulation (SVPWM) mode control, putting bi-directional inverter as the basic characteristics, having two operation modes: connection and islanding. When the power grid is relatively adequate, and at this time the electricity is in the trough, the converter works in the state of rectification, and it charges the energy storage battery through the power grid and store the energy. When power grid lacks of electricity, during the peak time, the bi-directional converter operates in the inverter state, and the power is fed back from the storage battery to the large power grid. At this point the inverter is used as a current source relative to the grid. But when the fault occurs in the power grid, the microgrid is in the state of isolated network, it can play a role of emergency independent inverter. At this point, the inverter can be used as a network power supply, and it is responsible for regulating the voltage and frequency of the microgrid. The controlled focus is outputting voltage waveform quality, and at this time, the energy storage inverter is used as a voltage source relative to the micro grid.