A Novel High-Gain Soft-Switching DC-DC Converter With Improved P&amp;O MPPT for Photovoltaic Applications

Chaoping Rao,Mohamed Sharaf,Mohamed A Mohamed,Mohammed A El-Meligy,Ali Hajjiah,Ahmed T Soliman

doi:10.1109/access.2021.3072972

Abstract

This paper proposes a novel high voltage gain structure of DC-DC converter with soft-switching ability for photovoltaic (PV) applications. A small size coupled inductor with one magnet core is utilized to improve the voltage conversion ratio in the proposed converter. The converter has one active MOSFET with low conducting resistance ( $R_{DS}-_{ON}$ ), which in turn reduces the conduction losses and complexity of the control section. Due to the low input current ripple, the lifetime of the input PV panel is increased, and the maximum power point (MPP) of the PV panel can be easily tracked. The MOSFET’s zero-voltage and zero-current switching and diodes are the other countenance of the proposed converter, which improve its efficiency. Additionally, an improved Perturb and Observe MPP tracking (IP&O MPPT) algorithm is introduced to boost the extracted power of the input PV sources. To validate the performance of this converter, the operation modes principle, steady-state and efficiency survey, and comparison results with other same family converters are carried out. Finally, an experiential prototype is built with 20 V input, 200 V output, power rate of 200 W, and 50 kHz operating frequency to validate the mathematical analysis and effectiveness of the proposed structure. The efficiency of the proposed converter was estimated by over 95% at various power levels.

Highlights

Researchers are focusing on solving the problems associated with Photovoltaic (PV) systems for DC distribution such as low voltage level, low reliability, and low efficiency [1, 2]
The usage of power electronic converters such as DC-DC converters is increased in some important applications, like uninterruptible power supplies (UPS) and electric vehicles (EV) [3]
The PV systems play a prominent role in the integration of hybrid renewable energy systems. These systems pose many challenges that should be addressed to make them more efficient and reliable [57]. One of such challenges is to locate the position of maximum power point (MPP) which changes instantaneously due to the non-linear characteristics of current-voltage (I-V) and powervoltage (P-V) that vary with varying climatic conditions

Summary

Introduction

Researchers are focusing on solving the problems associated with Photovoltaic (PV) systems for DC distribution such as low voltage level, low reliability, and low efficiency [1, 2]. These systems pose many challenges that should be addressed to make them more efficient and reliable [57] One of such challenges is to locate the position of maximum power point (MPP) which changes instantaneously due to the non-linear characteristics of current-voltage (I-V) and powervoltage (P-V) that vary with varying climatic conditions (i.e., temperature and irradiance). The conventional boost DC-DC converters are the simplest choice for increasing the output voltage level and have advantages of simple design, control, and implementation [12, 13] They have the drawbacks of high maximum potential stress across the diode and the power switch, and low potential conversion ratio at low duty cycles [14]. These converters can be categorized into bidirectional/unidirectional, isolate/nonisolated, hard switched/soft switched (ZVS and ZCS), and current fed/voltage fed structures [16]

Methods

Results

Conclusion