A Single Phase to Three Phase Buck-Boost Converter cum Voltage Regulator suitable for Wind Power

Abstract

In this paper the output of the single phase wind generator, common for low power application, is converted efficiently into a three phase power. A control system for impedance(z)-source inverter is designed for this wind power conversion. The variable single phase ac output of wind generator due to unpredictable variation in wind speed is suitably controlled through a closed loop system employing the buck-boost capability of z-source inverter. The z-source PWM in- verter replacing the conventional PWM inverter provides the unique output voltage regulation by making an appropriate choice of boost factor under both variable generator voltage and variable load conditions. The closed loop controller carefully monitors the wind generator voltage and controls the shoot-through and non-shoot through duty cycles of the inverter to develop a three phase steady boosting voltage, which is not possible by conventional PWM control. The whole system is designed and verified through simulation and hardware arrangement. The system is simulated under arbitrary generator output condition both in surge and sag states and results steady three phase voltage across load. Similar steady output is also observed in case of variable load condition. The proposed closed loop system, therefore, can be used for smooth and effective dynamic and steady state control maintaining the level of three phase output at a desired level.