Comparing effectiveness of hybrid mppt algorithms under partial shading conditions

© 2016 IEEE. For photovoltaic (PV) systems, a key area which can affect the amount of energy harvested is the effectiveness of the Maximum Power Point Tracking (MPPT) algorithm, which dynamically locates the operating point for maximum power output. Currently, there are many MPPT algorithms proposed and in use, however, they are not without problems. For example, algorithms such as the Fractional Open Circuit method are simple and effective, but their accuracy is poor. Other algorithms such as the Perturb & Observe (P&O) approach, although more accurate, will cause oscillations around the maximum power point. It is perceived that the use of two MPPT algorithms in tandem will help to overcome the drawbacks of individual MPPT algorithms used in isolation. This paper proposes two new versions of Hybrid MPPT algorithm; one being a combination of the Fractional Open Circuit Voltage and P&O methods, and the other a combination of the Power Increment and P&O techniques. Experimental results are reported to evaluate and compare the performance of the algorithms

A more accurate analog voltage-based photovoltaic maximum power point tracking technique

© 2017 IEEE. In this paper, an analog voltage based maximum power point tracking (MPPT) algorithm for individual photovoltaic (PV) panel is proposed. The fixed voltage reference method is the simplest method for tracking, but it does not give good MPPT efficiency because the MPP voltage point changes at different solar insolation levels. A roughly linear slope is formed when connecting the MPP points measured from the highest isolation level to the lowest. Utilizing this characteristic, a bipolar junction transistor BJT is used to implement a variable voltage reference that improves the accuracy of the maximum power point voltage when the insolation changes. The proposed circuit is simple and easy to implement and it can easily track the maximum power point without the need of a digital controller or PID controller, so the cost and circuit complexity is reduced

A Reconfigurable Three-Port DC-DC Converter for Integrated PV-Battery System

In this article, a new nonisolated three-port dc-dc converter to integrate a battery storage with a photovoltaic (PV) module is proposed for off-grid solar-power applications. The proposed converter can be used to integrate the PV module with a backup battery to minimize the impacts of renewable-energy intermittency and unpredictable load demand. The proposed converter is reconfigurable and able to operate as a conventional boost converter, a buck-boost converter, or a forward converter in different modes to support several power flow combinations and achieve power conditioning and regulation among the PV module, battery, and output port, simultaneously. Nevertheless, the power stage only consists of two switches, one coupled inductor, one diode, and two capacitors. A high-voltage conversion ratio is achieved by using a coupled inductor and by combining the PV module and the battery in series. Experimental results of the proposed converter operating in the steady state and during transitions between different modes are reported