Research On Dual Buck Inverter With Stand-alone And Grid-connection Operation Modes

The developments of renewable energy and distributed power generation have been attracted more and more attentions because of the lack of energy, pollution and shortage of concentrative power generation. The inverter system is an important part of distributed power generation. Grid-connection and stand-alone two operation mode inverter which has the merits of flexibility, high reliability and economy has been thought much of. A dual buck inverter (DBI) based on hysteresis current control is proposed, which has concise main circuit configuration, freedom from shoot-though problems and capacity to realize the optimum design of all power devises. The operation principle of DBI in voltage mode and current mode are analysed. The voltage controlled inverter is applied to stand-alone mode and the current controlled inverter is applied to grid-connection mode. To improve the reliability of inverter, the switching process between stand-alone and grid-connection is analysised and compare the merits or shortages of different methods. Some solutions are proposed and a kind of control algorithm for seamless transfer of DBI between stand-alone and grid-connection mode is presented. The scheme is adopted to design a dual mode inverter. A 500VA prototype converter is built to verify the effectiveness of the control algorithm, and the experimental results are also included in this paper.