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Power generation for renewable energy sources increased rapidly during last few years. Similarly, the high gain dc–dc boost choppers are taking place of conventional power converters used for photovoltaic (PV) appliances. Researchers are developing different methods in order to provide high voltage gain, low ripple, reduced switch stress, low converter costs, and minimized variations of PV operating points. This study proposes a two-stage converter for a freestanding water pumping motor drive power by solar PV system. According to the proposed system, at first, a high gain (HG) cell and a DC-to-DC boost converter are combined to increase the PV voltage to high levels. Later on, the resulting dc voltage feds a three-phase synchronous reluctance motor drive that operates centrifugal pump load. The perturb and observe approach is utilized to get the maximum power out of the solar PV module. Moreover, indirect field-oriented control is implemented to accomplish smooth starting of synchronous reluctance motor. In order to validate the effectiveness of proposed technique, a MATLAB/Simulink environment-based simulation setup along with an experimental prototype is developed. Additionally, various cases are considered based on different operating conditions and irradiance levels to collect and analyse the results. [ABSTRACT FROM AUTHOR]

The use of certain electrical equipment connected to conventional power systems has raised concerns regarding the quality of the power system. Some equipment has been perceived to be unequipped to sustain the surges, faults, and distortions in traditional distribution systems. Common voltage issues exist, such as imbalance, harmonic distortion, sag, and swell. Such issues are usually contained using a dynamic voltage restorer (DVR). In this study, the determination of voltage references for DVR based on a robust and simple detection method of positive and negative sequence components is analyzed. This method detects the components in real time. With the proposed method, either the reference load voltages can be generated, or the reference DVR voltages can be generated, depending on which voltages are controlled. Moreover, contrary to other methods, the proposed technique avoids the use of phase-locked loop (PLL) and vector transformation. The voltage compensation technique controls the DVR in real time to prevent steady-state and disturbance conditions at the load side. The proposed system is evaluated by simulation and experimentation under several steady-state and transient cases. Finally, the proposed control is compared with common control methods. [ABSTRACT FROM AUTHOR]

The propagation of nonlinear loads and distributed power generation systems can cause power quality problems such as harmonic distortion, system imbalance, and resonance problems. Shunt active power filters are used to eliminate these power quality problems. A recently proposed control scheme for a shunt active power filter utilized a time-domain transformation to extract positive and negative sequence components of the system voltages and currents. These components are used in a modified version of instantaneous reactive power theory to calculate the reference currents for a three-phase inverter. Changes in the system operating conditions can cause the system frequency to vary, which can impact the performance of the time-domain transformation. Proposed in this paper is a frequency adaptive control scheme to compensate for frequency variations. Several simulation and experimental tests have been performed to validate the operation of the proposed frequency adaptive control scheme. [ABSTRACT FROM AUTHOR]

This paper proposes a three-phase power factor correction (PFC) for a three-phase induction motor (IM) drive under normal and abnormal supply voltage conditions. A new technique of PFC based on a positive sequence components method is introduced. The PFC circuit uses a SEPIC converter with a single switch, which needs only one control signal. The PFC control method with the proposed technique provides nearly sinusoidal supply currents maintaining a high power factor under different supply voltage conditions. Furthermore, the PFC method maintains DC bus voltage at the desired value. The regulated DC voltage feeds a four-switch inverter of the three-phase IM drive system. Mathematical analysis of the equivalent circuits based on operation modes of the SEPIC converter is introduced. The performance of the proposed technique is evaluated under ideal and non-ideal supply voltage conditions. The results are analyzed in terms of reduction in the THD of supply currents and improvement of power factor. System validation performed in simulation and experiment has shown the effectiveness of the proposed system under different supply voltage conditions. [ABSTRACT FROM AUTHOR]