In this research work, a diode based circuit and an algorithm are proposed to detect, classify & localize faults in small or medium scale photovoltaic (PV) array with blocking diodes. Using a single voltage sensor for the whole PV array, the proposed method can detect line-to-line (L-L) & line-to-ground (L-G) faults and find the approximate number of faulty modules. In addition, the proposed circuit uses one voltage sensor to classify faults and one to detect the exact faulty string. Alongside, the proposed algorithm is capable of detecting low & high impedance faults. In contrast to complicated strategies, easy circuit analysis is done to examine the behavior of PV arrays in the event of faults. The proposed algorithm & circuit has been thoroughly tested through hardware prototype.

In this study, analysis of photovoltaic (PV) string currents is performed to understand the behavior of the PV array under faults. The whole analysis is summed up in just two simple statements, and an algorithm is devised on the basis of these statements. The proposed algorithm can detect, classify and localize line-to-ground (L-G) & line-to-line (L-L) faults in the PV array. The proposed method can detect faults of any mismatch level and size of the PV array by using only one current sensor per string. It is also capable of working with finite fault-resistance as well as in the presence/absence of blocking diodes. To check the accuracy of the algorithm, it has been thoroughly tested through experimental setup.

Small-signal models of dc-dc converters are often designed using a state-space averaging approach. This design can help discuss and derive the control-oriented and other frequency-domain attributes, such as input or output impedance parameters. This paper aims to model the dc-dc converters for PV application by employing a capacitor on the input side. The modeling, design, and analysis of the dc-dc converters regarding the input capacitor is limited in the literature. Five dc-dc converters, including buck, boost, buck-boost, ĆUK, and SEPIC converters, are designed and implemented using the state-space average modeling approach in MATLAB/Simulink. The circuit topology of each converter and the state-space matrices are derived considering every constraint. A rigorous and compelling analysis of the dc-dc converters is carried out to compare system stability and, ultimately, the dynamic performance. The output of the resulting small-signal models has been demonstrated in the time-domain against topology simulations. All the converters are exposed to unpredictable weather conditions and the simulations are carried out in the PSIM software. The perturb and observe (P&O) maximum power point tracking (MPPT) algorithm is applied in all the converters to ensure maximum power point (MPP) achievement. The results showcase that the boost converter outperforms all other converters in terms of stability, settling time, and overshoot.

Photovoltaic (P.V.) systems have become an emerging field for power generation by using renewable energy (RE) sources to overcome the usage of conventional combustible fuels and the massive release of dangerous gases. The efficient operation of the PV system is vital to extracting the maximum power from the PV source. For this, a maximum power point tracking (MPPT) algorithm works with a DC–DC converter to extract maximum power from the P.V. system. Two main issues may arise with the involvement of a converter: (1) to locate M.P.P and (2) the performance of the PV model in varying weather conditions. Therefore, designing any converter gain has the utmost significance; thus, the proposed work is on non-isolated boost converters. To calculate the values of specific parameters such as input capacitor, output capacitor, and inductor, the averaging state-space modeling typically uses governing equations. In this research, the formula of the input capacitor is derived through the average state-space modeling of the boost converter, which signifies the relation between input and output capacitors. From the results, it has been proven that the input capacitor efficiently performs when the input capacitor is half of the output capacitor. At an irradiance level of 1000 W/m², the system shows stable behavior with a fast convergence speed of 0.00745 s until the irradiance falls to a value of 400 W/m². The system is less stable during the morning and the evening when irradiance falls are very low.

Sliding mode controller (SMC) based MPPT systems are less effective due to input LC_in tank of boost converter. The LC_in tank at PV node creates the sinusoidal waves of V_pv/I_pv, due to which phase angle (φ) occurs between triangular wave of inductor current (I_L) and sinusoidal V_pv. This creates the adverse effects on SMC operation. In this research work, a series capacitor based boost converter is developed without using the parallel LC_in circuit. Consequently, V_pv/I_pv becomes triangular (pure/semi) and φ factor between V_pv and triangular I_L is minimized. The proposed setup ensures a high frequency operation and better voltage regulation of SMC. Through theoretical, mathematical and experimental studies, the response of PV source with conventional converter and proposed converter have been analyzed. Finally, extensive simulation studies and experimental evidences are presented, which highlights the superior dynamic and steady efficiencies of PV system with proposed topology as opposed to conventional converter and other recently developed MPPT systems.