A Method for Power Conditioning with Harmonic Reduction in Microgrids

Abstract

This paper presents a control method ofRenewable Energy Sources (RES) to reduce the harmonic content of the distribution system to which are connected, such as a Microgrid. By this method the RES is acting as a Power Conditioner and its supplying system consists of a buck-boost converter connected back-to-back to a polarity swapping inverter. A RES or a Distributed Generator (DG) such as a microturbine is synchronized to the distribution system, which is assumed to be distorted by a high-order voltage harmonic. Utilizing the proposed method, the RES not only exports its output power to the grid, but also reduces the existing harmonic distortion, improving voltage quality at the Point of Common Coupling (PCC). Simulations in Matlab/Simulink platform have been performed in order to verify the effectiveness of the suggested approach to reduce harmonic content.

Multipurpose Power Converter for Non-Grid-Connected Microsystems

“…Furthermore, methods based on selective harmonic elimination suppress harmonics caused only by the operation of the converter itself. Our method, tackles the harmonic content of the output, no matter if it is created by the converter, the source, the isolated loads or microgrid [12].…”

“…4624-4632], [12]. The harmonic content of the output is calculated with a fast Fourier transformation (FFT).…”

“…1082-1093]. Electric appliances for non-grid connected or mobile households do not always follow the standard 110 or 230 V ac supply requirement, but may require one of the various dc voltage levels (12,24 or even 48 V). Thus, up to now, the industry produces different types of converters in order to properly interface those sources with loads.…”

Current Harmonics Compensation in Microgrids Exploiting the Power Electronics Interfaces of Renewable Energy Sources

“…Therefore it is suitable either for simple current harmonic reduction or as a self-healing mechanism. Having in mind [16], it can be concluded that the proposed topology can provide both voltage and current harmonic reduction in microgrids (or generally in distribution systems), depending on which kind of distortion exists. Finally, the above mentioned theory and simulation results were experimentally confirmed.…”

“…The converter configuration proposed in [15] and already used in [16] has been used in this work in order to reduce the current harmonic content of the grid, so that the Total Harmonic Distortion (THD) index is decreased to below acceptable limits. It consists of a dc/dc buck-boost converter connected to the grid through a simple polarity changing inverter.…”