Research On The Wave Control And Auxiliary Funcitons Of Inverter

The inverters are widerly used in many important situation, where Fast response and little distorted output voltage is required. It is needed and significative to improve the quality of output voltage. This dissertation focuses on the output voltage control and some important function of three phase inverters. The followings are the main work:Three phase inverters are multi-input multi-output coupling systems. With the introduction of the concept of voltage space vector and coordinate transformation, it is possible to let three-phase system transform among the different coordinates. Supposing load as disturbance, models in ABC three phase stator coordinate,αβtwo- phase stator coordinate and dq two-phase rotating coordinate are established. Using MATLAB, the inverter simulating model is established where dead time effect is considered.Finally the several affect output voltage reasons are analysed.To achieve high quality output voltage, diverse voltage waveform control techniques have been developed. Based on the characters of three phase systems in dq coordinate, repetitive control strategy is introduced and one repetitive controller is designed for a system.Using MATLAB,the simulation waves are got . With the mathmatics analysis and these waves ,the repetitive control faults that are slowly dynamic response and steady error are explained. one control strategy is present which is base component instantaneous feedback control model paralleling with harmonic component repetitive controller is given to solve these faults.Comparing the output voltage of repetitive controller with instantaneous feedback controller paralleling with repetitive controller, the merits of instantaneous feedback controller paralleling with repetitive controller are pointed out. In order to safely supply power to load ,the inverter functions of switching and current limiting are designed. Two inverters use the digital phase lock loop to ensure they have accord phase. The paper analyzed the main cause causing the magnetic bias and proposed a sofware method. Experimental result proves that the proposed method is very simple and practical and the system quality and reliability is improved.