Analysis of High-Efficiency Transformerless Inverter for a Grid-Tied PV Power System with Reactive Power Control

Abstract

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 (V α and V ß ). 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 P ref 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.

Key findings

• ▸The proposed Fuzzy gain scheduling controller outperforms conventional PI controller based active and reactive power controllers.
• ▸The HETL inverter with Fuzzy gain scheduling controller meets the reactive power control requirements of VDE-AR-N4105 standard.
• ▸The proposed scheme improves the power factor and efficiency of the grid-tied PV system.

Keywords

Identifiers

DOI

10.2174/2213275911666190320161342

Journal

Recent Advances in Computer Science and Communications

Year

2021