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Input harmonic and power factor (PF) regulations necessitate the use of front end active PF correction (APFC) circuit for power electronic converters. In recent times, the VIENNA rectifier has become a popular choice for three-phase APFC applications. The converter is a fifth-order system and results in a highly complex model. This calls for a complex control design procedure and involves enormous computation requiring the use of a high end digital signal processor (DSP). This can be simplified if the order of system is reduced. In this study, it is proposed to decouple and analyse the converter as three independent single phase units operating in parallel with current mode control, thereby reducing the order to two, simplifying the analysis and control design. The transfer function of the proposed small-signal model is derived and its Bode plot is drawn. A high bandwidth inner average current controller and a low bandwidth outer voltage controller are designed to obtain a 60°phase margin. With the proposed design, a 10 kW prototype VIENNA rectifier is developed with a low cost analogue integrated circuit (IC) and validated. The results obtained prove the accuracy of the proposed model and effectiveness of the control. Single phase operation is also made feasible with the proposed technique.

The performance of the solar photovoltaic system is affected by the unpredictable phenomenon of partial shading. This causes the mismatch losses that suppress the power generation of healthy PV modules in it. The objective of the proposed work in this paper is to bring out the maximum power from each PV module in the PV array by reducing the mismatch losses. A new array configuration method is proposed in this paper, which follows the screw pattern in the row formation. Each PV row is created with distinct PV modules from the rows of the conventional array configuration. This proposed work allows the PV system to operate with minimum mismatch losses by even shade dispersion over the PV array. The proper mathematical expression with all necessary constraints was derived for the array formation of the proposed work. The output analysis is been validated in the simulation of the 9X9 PV array in MATLAB/Simulink®. The mismatch loss generation and output power enhancement are measured and compared with the various conventional array configuration methods under six kinds of partial shading patterns. The proposed array configuration is 40% more efficient than the conventional series-parallel array configuration and also performs better than the total cross-tied and sudoku puzzle pattern methods. The shade dispersion rate of the proposed array configuration has highly reduced the mismatch losses in the PV system and hence, it improves the power output.

Power conversion efficiency is the most important factor to be considered in PV systems because it is affected by various environmental conditions. The effect of partial shading is the most influenced factor in the reduction of power output. Various research schemes like Maximum Power Point Tracking (MPPT), array configuration scheme, reconfiguration, etc., work on the PV system to reduce the impact of partial shading. This paper presents a new kind of array configuration scheme that forms the PV array based on the moves of the Knight coin in the chess game. This arrangement creates the squared PV array of rows with distinct PV modules which is capable of evenly dispersing the shading in the partially shaded PV array. Also, this scheme is applicable for the non-squared PV arrays to create PV rows with the PV modules from a distinct location or from the same row with optimized distance to disperse the maximum level of shading. The proposed method has been discussed with the proper mathematical formulation with all necessary constraints and also it been validated with the hardware arrangements and MATLAB/Simulink ® model.

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