A High-Performance Adaptive Incremental Conductance MPPT Algorithm for Photovoltaic Systems

Chendi Li,Yuanrui Chen,Jun Zeng,Junfeng Liu,Dongbao Zhou

doi:10.3390/en9040288

Abstract

The output characteristics of photovoltaic (PV) arrays vary with the change of environment, and maximum power point (MPP) tracking (MPPT) techniques are thus employed to extract the peak power from PV arrays. Based on the analysis of existing MPPT methods, a novel incremental conductance (INC) MPPT algorithm is proposed with an adaptive variable step size. The proposed algorithm automatically regulates the step size to track the MPP through a step size adjustment coefficient, and a user predefined constant is unnecessary for the convergence of the MPPT method, thus simplifying the design of the PV system. A tuning method of initial step sizes is also presented, which is derived from the approximate linear relationship between the open-circuit voltage and MPP voltage. Compared with the conventional INC method, the proposed method can achieve faster dynamic response and better steady state performance simultaneously under the conditions of extreme irradiance changes. A Matlab/Simulink model and a 5 kW PV system prototype controlled by a digital signal controller (TMS320F28035) were established. Simulations and experimental results further validate the effectiveness of the proposed method.

Highlights

With the increasing problem of environmental pollution and approaching depletion of conventional fossil-fuel energy sources, solar energy, as a clean, environmentally-friendly and abundant energy source is attracting more attention
It indicates that larger step size significantly improves the response fixed step size incremental conductance (INC) method, the variable step size method partly solves the contradiction between time, but more power loss is incurred due to the steady state oscillation of the converter duty cycle
As the scaling factor N is set as 1 and the steady state; the average output power of PV array is 175.4 W at 1000 W/m2, and the the upper limit of step size ∆Vrefmax 2is set as 4.8 V in [13] and experiments show that the parameters tracking time of 300 to 1000 W/m is 0.22 s

Summary

Introduction

With the increasing problem of environmental pollution and approaching depletion of conventional fossil-fuel energy sources, solar energy, as a clean, environmentally-friendly and abundant energy source is attracting more attention. An effective way of using solar energy is photovoltaic (PV) generation; the output characteristics of PV arrays vary with the environment (cell temperature and irradiation). Fractional open-circuit voltage (FOV) [4] and fractional short-circuit current (FSC) [5] methods take advantage of the approximate linear relationship between operating voltage or current at the MPP and open-circuit voltage or short-circuit current of PV arrays; they are simple and effective ways to track the MPP. FOV [4] and FSC [5] have already been used for PV systems of street lighting, as the precise tracking is unnecessary for it.

Methods

Results

Conclusion