Control Scheme for a Novel Photovoltaic Inverter

A novel photovoltaic inverter is introduced.The inverter can work in local load mode and grid-connected mode.Mathematical models of the inverter are built in the two modes.When working in local load mode,the main circuit of in-verter can be considered as a two-order system and the voltage loop control should be mainly considered.When working in grid-connected mode,the main circuit of inverter can be simplified to a one-order system and current loop control should be mainly considered.The controllers are designed and the control schemes are described respectively in the two modes.The frequency field simulation results prove the stability of the control system.A 3 kW inverter is set up in the laboratory,the loop algorithm and control are accomplished by a DSP.A good experimental result is achieved.