Voltage quality and power quality factor improvement using active power line conditioner

摘要

This project describes an improvement method of power quality using shunt active power line conditioner (APLC) for a distorted three phase supply system feeding three phase unbalanced non-linear load. A control algorithm is presented for an APLC to compensate harmonics and unbalance factor. Sensing load currents, dc bus voltages compute reference currents of APLC. APLC driving signals are produced with the reference signals via a hysteresis band current controller. The case of distorted supply voltage condition has been considered. The p-q theory based active power line conditioner degrades in case of non-ideal source voltage condition. The use of self-tuning filter (STF) is proposed in order to improve the harmonic suppression efficiency of APLC. MATLAB/simulink power system toolbox is used to simulate the proposed system. The proposed method restricts both THD and unbalance factor of input currents and a power quality factor is designated which integrally reflects the two quality aspects (i.e., harmonic and unbalance factor) before and after compensation. Power quality factor improvement with the proposed shunt APLC has been verified by the simulation results.