J. Fallah Ardashir, M. Sabahi, S. H. Hosseini, E. Babaei, G. B. Gharehpetian,
Volume 13, Issue 2 (June 2017)
Abstract
This paper proposes a new single phase transformerless Photovoltaic (PV) inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC) technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.
Amir Gallaj, Jaber Fallah Ardashir, Mojtaba Beiraghi,
Volume 18, Issue 4 (December 2022)
Abstract
This work proposes a high step-up interleaved dc/dc topology utilizing a VM (voltage multiplier) cell suitable for PV applications. The VM cells D/C (Diode/Cap.) are cascaded among the phases to approach a high voltage gain. Besides, the voltage converting ratio of the presented structure can be improved by extending the VM cells and it also leads to drop in the normalized voltage stress throughout the switches and some diodes. Therefore, by utilizing a semiconductor (Switch/Diode) with a lower rating leads to a decline in system losses. Also, the efficiency of the suggested topology will be considerable and the overall cost can be decreased. To elaborate on the main benefits of the proposed topology, a comparison has been made across other literature regarding the efficiency, peak voltage throughout the semiconductors and voltage ratio of the converter. To prove the accuracy principle of operation of the suggested converter, two prototypes (for n=1, 2 stages) were built and tested at 350 W and 453 W with an operating frequency of about 40 kHz performed.
