Research on an Improved Method for Maximum Power Point Tracking of Photovoltaic - Advanced Research on Computer Education, Simulation and Modeling - page 298

Research on an Improved Method for Maximum Power
Point Tracking of Photovoltaic
Bin Wang 1,2 , Chunfu Gao 2 ,Xinsheng He 2 , and Zhiyong Luo 1,2
1 School of Mechanical and Electronics Engineering, Lanzhou Jiaotong University
730070 Lanzhou, China
2 College of Engineering, Zhe Jiang Normal University
321004 Jinhua, China
{computerwangbin,onliday}@163.com,
{cfgao2007,xsh}@zjnu.cn
Abstract. In order to improve the efficiency of photovoltaic, it is necessary to
track the maximum power point(MPP) all the time. After studying various algo-
rithms, a new algorithm was presented based on online short-circuit current,
open-circuit voltage, and variable step of perturbation and observation method.
This algorithm could track MPP change rapidly and accurately without the dis-
turbance of photovoltaic system, and also can reduce the power oscillation
around MPP and the light mutation of the false judgement phenomenon. The
simulation results show that the algorithm has a good dynamic and steady-state
performance.
Keywords: MPPT, short-circuit current, open-circuit voltage, perturbation and
observation method, variable step.
1 Introduction
The output of photovoltaic (PV) has obvious characteristics of non-linear, which is
effected by the external environment. In order to make the power output of PV maxi-
mize, the output of PV requires the maximum power point tracking (MPPT). There
are many techniques that have been proposed for tracking the MPP of PV: open-
circuit voltage method, short-circuit current method, perturbation and observation
(P&O) method, incremental conductance (INC) method, and fuzzy control method
[1]. Open-circuit voltage and short-circuit current method offer a simple and low-
priced way to acquire the maximum power. Nevertheless, they have a larger steady-
state error and low energy conversion efficiency. P&O method is widely applied in
the MPPT controller due to its simplicity and easy implementation, but its accuracy in
steady-state is low and when the insolation is changed rapidly, the P&O method
probably failed to track MPP. INC method has the advantage of fast tracking and
dynamic stability, but which is difficult to determine the appropriate steps. Fuzzy
control method does not need to study the specific characteristics of PV, but deter-
mining the shape of membership functions needs more experienced designers [2].
According to the characteristics of PV and various control algorithms, a new MPPT