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A fast and parameter-intensive maximum power point tracking (MPPT) technique is presented for a photovoltaic (PV) water pumping system, driven by the brushless dc motor (BLDCM). The technique is based on the application of “ripple correlation control”. As an advantage, rather than artificial signal injection, the proposed technique employs the inherent perturbations introduced due to phase commutation and nonsinusoidal back-EMF of BLDCM to determine the maximum power points of the PV system. The technique can be simply employed for different configurations of BLDCM-based PV water pumping systems. Experiments are performed to demonstrate the effectiveness of the proposed technique.

Balanced current sharing and output voltage control of paralleled DC–DC converter modules are essential requirements for enhanced reliability and power capacity. These control goals are challenging due to the load, supply voltage, line impedance uncertainties, inter-couplings of the converters, and open circuit faults. To achieve these goals, this paper proposes two novel adaptive fuzzy backstepping control methods for two sets of paralleled DC–DC converters. The proposed controllers are exercised in a master–slave architecture. First, a master–slave adaptive fuzzy backstepping controller is suggested for a set of paralleled buck converters to deal with matched and mismatched uncertainties, and to ensure balanced current sharing. To counteract uncertainties, as well as interactions among the converters, adaptive fuzzy estimators are employed. However, the suggested control strategy is not applicable to the paralleled boost converters due to their non-minimum-phase nature. Therefore, a novel master–slave adaptive fuzzy backstepping controller with a conventional proportional-integral reference current generator is proposed to encompass paralleled boost converters. Moreover, a simple fault-tolerant structure is suggested to detect the open circuit faults and re-share the inductor currents. The stability of the proposed controllers is guaranteed through the Lyapunov stability theorem. The proposed adaptive fuzzy backstepping control strategies offer good output voltage quality and current sharing, despite the uncertainties, inter-couplings, and open circuit faults. Comparative simulations are carried out on sets of three paralleled buck and boost converters to demonstrate the effectiveness and performance of the new control methods.

•In the proposed PV-DFIG hybrid system by employing a novel control scheme for PV-DFIG-BESS system and removing the BESS voltage control loop, the charge/discharge control system has become uncomplicate and cost effective.•In comparison with the conventional hybrid systems, by considering a battery energy storage and optimal control of converters in the proposed system, installing a PV system with the capacity more than the related converter is provided.•The proposed system provides an economical solution for combining PV and grid. In this configuration, by removing the PV converter, the number of system converters is reduced.•The PV-DFIG hybrid system is able to operate at its MPP in spite of [6] and therefore the DC-link voltage is kept in the nominal value continuously, even during the adverse condition (high wind speed and irradiation intensity).

This paper proposes a control strategy for important transients of a single-stage, three-phase, PV system that is connected to a distribution network. The proposed control strategy adopts an inner current-control loop and an outer DC-link voltage control loop. The current-control mechanism renders the PV system protected against external faults, enables control of the DC-link voltage and, therefore, controls/maximizes the PV system power output. The paper also proposes a feed-forward compensation strategy for the DC-link voltage control loop to mitigate the impact of the nonlinear characteristic of the PV array on the closed-loop stability, and to permit design and optimization of the DC-link voltage controller for a wide range of operating conditions. A mathematical model and a control design methodology are presented for the PV system, and it is shown that under the proposed control, the PV system fulfills the operational requirements of a grid-connected PV system. The effectiveness of the proposed control strategy and the most important transients of the PV system are evaluated through simulation studies conducted on a detailed switched model of the PV system in the PSCAD/EMTDC software environment.

This paper proposes a control strategy for important transients of a single-stage, three-phase, PV system that is connected to a distribution network. The proposed control strategy adopts an inner current-control loop and an outer DC-link voltage control loop. The current-control mechanism renders the PV system protected against external faults, enables control of the DC-link voltage and, therefore, controls/maximizes the PV system power output. The paper also proposes a feed-forward compensation strategy for the DC-link voltage control loop to mitigate the impact of the nonlinear characteristic of the PV array on the closed-loop stability, and to permit design and optimization of the DC-link voltage controller for a wide range of operating conditions. A mathematical model and a control design methodology are presented for the PV system, and it is shown that under the proposed control, the PV system fulfills the operational requirements of a grid-connected PV system. The effectiveness of the proposed control strategy and the most important transients of the PV system are evaluated through simulation studies conducted on a detailed switched model of the PV system in the PSCAD/EMTDC software environment.