High Gain Observer-Based Control for Grid-Connected PV System Under Partial Shading Effect

Abstract

This paper proposes the new high-gain observer dedicated to the SEPIC converter and the single-phase inverter. The high-gain observer is designed in order to minimize the number of sensors required, because the use of voltage and current sensors have many disadvantages. In fact, these sensors can obtain a bulky system, also, they are expensive and take up more place. Also, this paper proposes new controller able to locate and track the global maximum power point under the partial shading effect. Actually, when the partial shading occurs, the Power-Voltage curve presents more than one maximum power point, which are divided between the global maximum and the local maximums. The global maximum presents the superior one, while the local maximums present the inferior ones. The classical methods like Perturb and Observe and Incremental Conductance are no longer able to distinguish the global maximum point. So, they cause a high drop of power, which justifies the need of a controller that can solve such problems. Effectively, the proposed controller is designed for this purpose, it consists of an algorithm able to locate the global maximum power point and generate the reference input of corresponding voltage. Also, this controller consists of the sliding mode controller that is able to track the reference input by acting on the SEPIC converter's duty cycle. In addition, the SEPIC converter is connected to the grid through the single-phase inverter. However, to make this connection, it should unify the power factor and synchronize the inverter current with the grid voltage. Effectively, these two tasks are solved by designing the sliding mode controller that acts on the inverter duty-cycle to allow its current to be in the same shape and phase as the grid voltage. Also, the DC bus voltage is regulated by using the PI controller. The overall system is modelled mathematically, tested and validated under Matlab/Simulink environment to show the criteria's performances and efficiency improvement of PV panel by using the proposed Global Maximum Power Point Tracking controller. Moreover, the proposed controller is compared with the hybrid controllers: P&Osliding mode, IC-sliding mode and PSO-Backstepping controllers. The results illustrate the performance of the proposed controlled to distinguish and track rapidly (about 40ms depending on the shading pattern), and accurately the desired global maximum power point.

Q-Learning Hybrid Type-2 Fuzzy Logic Control Approach for Photovoltaic Maximum Power Point Tracking Under Varying Solar Irradiation Exposure

“…Consider Eq. (7,9) and the MOSFET being switchoff, then the relation between input and output voltage is shown in Eq. ( 10)…”

“…Hybrid strategy of PSO-SMC [5] meets high accuracy and fast transient response yet cannot dispel of power undershoot response. Some other mixed method such as ANN-Backstepping SMC and high gain observer [6], SMC and high gain observer [7], backstepping integral sliding mode controller (BISMC) [8] have been developed by researcher with accurate and fast response.…”

Backstepping Integral Sliding Mode Control Method for Maximum Power Point Tracking for Optimization of PV System Operation Based on High-Gain Observer

“…To prove more the proposed controller effectiveness under the environmental condition changes, this controller is compared with the twostage methods which are the backstepping combined with the P&O and the PSO algorithms, presented respectively in [17,18]. These results are displayed in Figs.…”

“…2 illustrates the Photovoltaic generator (PVG) model used in this work, which consists of a photocurrent source and a diode connected with series and shunt resistances. In this work SM55 PV module is adopted to achieve a necessary voltage [13].The characteristic of the Photovoltaic generator can be presented by the following equations:…”

“…International Journal of Intelligent Engineering and Systems, Vol. 13 Moreover, this controller is combined with the high-gain observer in order to minimize number of sensors required. From the simulation results, the high-gain observer proves its ability to replace some sensors of the voltage and the current.…”