Micro Inverter Network Control And Operation Based On

The development of micro-grid technologies are promoted by the utilization of renewable energy and new energy which connected to the micro-grid as a form of distributed generation in order to make it become a reliable and flexible single-controlled grid. Micro-grid includes two modes, one is networking mode, another is islanding mode, and can enhance the reliability of power supply in loads side. Micro-grid, as to be the traditional supply for transmission network, represents a new direction of the electric power development.Most of the distributed generations are connected to micro-grid by interface of power electronics, it makes the controlling of distributed generations more flexible. The controlling of micro-grid is operated by inverters. Micro-grid’s operation and controlling methods based on the inverters are mainly about P/Q-controlling, droop-controlling, V/f-controlling, etc. Contrast to all of the methods, the droop-controlling has been taken more attention for many advantages such as with no need for communicated connection, low system cost, high reliability, plug and play function, and so on.In this paper, the controlling strategy of micro-grid based on distributed generations through interface of inverters and operating characteristics of micro-grid based on the strategy was analyzed. Working principles, control methods, PWM technology and PLL technology related to controlling about inverters was analyzed in theoretically. By established mathematical models of three-phase voltage source inverters in which the LC filter and its filtering effects was considered, it discussing the strategies of micro-grid P/Q and droop-controlling. The effective of each strategy was verified by numerical examples. Meanwhile, operating characteristics of different operate condition in mode of intentional islanding was mainly analyzed. The reliability of droop-controlling strategy in different operating condition of intentional islanding mode was verified.