Capacitance requirement in a three-phase SEIG under no-load and load conditions

Selection of appropriate size of capacitance is very important to buildup voltage in a self-excited induction generator (SEIG). This paper proposes a simple method of determining the actual size of capacitance needed in a three-phase SEIG to obtain a pre-specified voltage under no-load and load conditions. The problem of determining the capacitance is formulated in a very general way so that the same set of equations and the solution technique can be used for both no-load and load conditions as well as for fixed and variable speed operations. Unlike most of the previous methods, explicit expression of the equations in terms of actual unknowns is not needed and thus the lengthy and tedious algebraic manipulations of the equations can be avoided. The formulated problem is then solved using a numerical based routine given in MATLAB. The proposed method is then tested on a three-phase, 220-V, 1.5-kW induction generator for various operating conditions. The simulation results obtained by the proposed method are also compared with the corresponding actual values found through an experimental setup and are observed to be in very good agreement.