Selection of capacitors to regulate voltage of a short-shunt induction generator
A self-excited induction generator (SEIG) has poor voltage regulation and that restricts wide applicability of the generator. A simple method of selecting the values of fixed and switched capacitors in a short-shunt SEIG driven by a regulated prime mover to maintain the load voltage within the upper and lower acceptable limits is proposed. The values of the capacitors are selected very carefully to minimise the number of switched capacitors needed to satisfy the above voltage criterion, and that would minimise the cost and complexity of the voltage regulator. This requires evaluating the generator characteristics under constant voltage operation. The equations needed to obtain such characteristics are also derived and solved using a numerical based routine ‘fsolve’ given in MATLAB. The proposed method of selecting the capacitor values is then tested on a three-phase, 1.5 kW induction generator operating in a short-shunt configuration. 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.
