Implementation Of Average Model Of Inverter Using Transient Simulation Techniques

Within the last decade, there have been rapid changes in technology. Power electronics have played a vital role in the technological developments. Inverters are extensively used in power electronic applications for converting DC (Direct Current) to AC (Alternating current). The applications of inverters range from uninterrupted power supplies used in home appliances control to HVDC power transmission. Inverter circuits are quite complex and modelling of inverters have been studied extensively by researchers. In [1], the authors present a generalized state space averaging model of inverter, by taking dead time into consideration. The proposed model guarantees accuracy in fundamental components of voltage and current. The model proves to work well in controller design of parallel connection of inverters. An average inverter model working in two complementary modes like the current controlled mode and the voltage controlled modes is discussed in [2].The proposed model takes into consideration the the nonlinear behavior of the switches, delays in the control loops, and the practical constraints. The authors were able to simulate active and reactive power controls of the inverter in two different ways and also to estimate the low order harmonics of the output current, using the proposed model. Most of the existing inverter models are valid for a specific topology under study and models adopt a balance assumption among input variables, which limit their application ranges. A new-formed model which is a general one and more suitable for computer simulation is presented in [3]. The proposed model makes no extra assumptions and the equation are formed using KVL (kirchhoff voltage law) and KCL (kirchhoff current law).The model is a general one and can be applied to type of source/load voltages. A functional simulation model for the voltage-source inverter (VSI) using the switching function concept is proposed and implemented in [4]. With the functional model, the simplification of the static power circuits can be achieved and also need for forming the state equations describing the power circuits in MATLAB is not required. This paper presents the implantation of an average model of the three phase inverter using transient simulation methods. Section II gives the average model of the three phase inverter. Section III gives the transient simulation implementation of the inverter average model. Section IV gives the simulation and results.