| The control technology of grid-connected inverter, as the key technology in renewable energy generation system, have been attracted more and more attentions. The frequency of switching is slower in the high power grid-connected inverter. Compared with tradition type L or type LC, output filter and output current's THD of type LCL are all smaller. In this paper, a control method based on virtual resistor concept is designed in order to resolve output shake of grid-connected inverter.Merits and demerits of several typical grid-connected control methods are discussed. A type of LCL filter and LCL control method's mode are designed. Current forward feed is added in order to raise the speed of response of control current. Because resonance exists in the type LCL filter, if the resistance is addition to the capacitance, the stabilization of system is increased but loss is produced. In this paper a controlling strategy based on virtual resistor concept is presented to make controlling arithmetic replacing function of damping resistor .This way, not only can raise the stabilization of system but also can decrease the power loss. The inverter can only be operated in grid-connected mode or stand-alone mode, this plan is carried on the theoretical analysis and is carried on the simulation with the Matlab software.The result has proven this control programme feasibility.The driving and main circuit are designed in the paper, with TMS320LF2407A DSP control system.The experiments of grid-connected are carried on used the numerical control and the experiment results are achieved and the LCL inverter can operate not only in grid-connected mode but also in stand-alone mode. The important waveforms are analyzed and some questions are discussed.
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