Background: In recent days grid-tied PV power systems play a vital role in the entire energy
system. In a grid –tied PV system Transformerless Inverter (TI) topologies are preferred for its
reduced price, improved efficiency, lightweight etc. Therefore many transformerless topologies have
been proposed and verified with real power injection only. Recently, almost every international
standard has imposed that a specified amount of reactive power should be handled by the grid-tied
PV inverter. According to the standard VDE-AR-N4105, grid-tied PV inverter of power rating below
3.68kVA, should attain Power Factor (PF) from 0.95 leading to 0.95 lagging.
Objective: To address this issue of grid-tied PV system with reactive power control, in this paper
Fuzzy gain scheduling controller is proposed as a power controller for High Efficiency Transformeless
(HETL) inverter. The performance of the proposed scheme is analyzed and validated with the
comparison of a conventional PI controller based active and reactive power controllers.
Methods: This paper is with the intention of improvement in the performance of the system, the
FGS controller is anticipated as active and reactive power controllers. In conventional PI controller
gains are constant for any value of the error, which makes error and delay in optimum value of voltage
(Vα and Vß). Hence in this analysis FGS controller tunes PI controller gain with respect to
change in active and reactive power error.
Results: Comparative performance of PI and FGS based HETL inverter is presented in this paper. It
is noted that for any cases either Pref is constant or variable the FGS reduces ripple than PI based
HETL inverter system. Compare to constant reference power case variable reference case produces
more ripples in both systems.
Conclusion: From the analysis FGS based HETL inverter in a grid-tied PV based power system
produces the best performance in all aspects such as voltage, active power and reactive power.