This work proposes the design and experimental investigation of fuzzy precompensated hybrid proportional-integral (PI) controller for permanent magnet synchronous motor (PMSM) driven standalone solar water pumping system. Conventional proportional integral (PI) controller usually has fixed gains, which makes them quite sensitive to the parameter variations. In order to improve its performance, both during dynamic and steady state conditions, the presented controller introduces a fuzzy logic controller (FLC), which processes the speed error. The speed along with the processed output is inputted to the PI controller for speed control of PMSM. This topology uses a solar photovoltaic (PV) array to convert the solar power into electrical power. The energy obtained is utilized to rotate the PMSM using a 3-φ voltage source inverter. The PMSM is coupled to a pump, which performs the water pumping. An intermediate stage DC – DC converter is utilized to maximize the power output using an incremental conductance algorithm. A PV feed-forward term is incorporated to provide an accelerated performance. This topology is modelled and its response is manifested through simulation studies using MATLAB/Simulink under different atmospheric conditions. A hardware validation of it is also carried out using a digital signal processor controller (dSPACE DS-1004) on a developed laboratory prototype.

This paper deals with an effective power transfer scheme between the a solar photovoltaic (PV) array and single-phase grid, feeding a field-oriented controlled (FOC) permanent magnet synchronous motor (PMSM) drive applied to a water pumping system (WPS). Owing to the intermittency associated with solar (PV) system, the requirement of constant water supply is not possible with standalone system. In order to mitigate this, a grid intergraded WPS is proposed here. The grid integration enables the consumer an uninterrupted operation of water pump irrespective of solar insolation level. Moreover, the PV power can be fed to utility grid when water pumping is not required. To make it possible one voltage source converter (VSC) and one voltage source inverter (VSI) connected to a common DC link, are used for utility grid and PMSM control, respectively. The unit vector template theory is utilized to generate switching pulses for VSC to control the bidirectional power flow between the solar PV system and utility grid through the common DC link. A sensor-less FOC is used to drive the PMSM coupled to water pump. An intermediate stage boost converter is used for extracting optimum power from solar PV array under variable insolation. A perturb and observe algorithm is used for generating the duty ratio for maximum power point (MPP) operation. The proposed system is simulated in MATLAB/Simulink environment with SIM Power system toolbox and validated on a prototype developed in the laboratory. The system prototype is tested under variable solar insolation and grid abnormalities such as voltage sag and voltage swell.

Ensuring electrification of remote locations continues to be a major challenge for power engineers. To deal with the effect of intermittent nature of wind, this paper presents the design and implementation of a composite sliding mode controller (CSMC) for a battery energy storage (BES) supported solar photovoltaic (PV)–wind hybrid system in a remote location. This control technique comprises of a soft-switching sliding-mode observer (SS-SMO) and a nonsingular terminal sliding mode controller (NTSMC). The SS-SMO is used to observe the disturbances, whereas the NTSMC is used as a speed controller. The chattering problem caused by the conventional sliding mode controller is alleviated by replacing the conventional signum switching function with the smooth hyperbolic tangent function in disturbance observer loop. The fast and finite time convergence NTSMC based speed controller along with the SS-SMO based disturbance rejection unit, serves the benefits of CSMC. This technique exhibits robustness against model uncertainties and external disturbances. Moreover, the complexity of the system is reduced by replacing the mechanical speed and position sensors with parameter estimation. A double-stage configuration using a dc/dc boost converter is adopted for a PV system. A comparative analysis is presented between the proposed and conventional techniques. A prototype of the hybrid system is developed in the laboratory with permanent magnet synchronous generator. The CSMC-based controller with disturbance rejection ability is implemented to harvest peak wind power. A perturb and observe maximum power point tracking technique is adopted to harvest peak solar power. A voltage control technique is adopted to maintain the voltage at the point of common coupling.

This work proposes a microgrid (μ-grid) integrating wind and solar photovoltaic (PV) resources, along with the battery energy storage (BES) to the three phase grid feeding the nonlinear load. The μ-grid disconcerted by probabilistic nonlinear time dependent parameters and their effects are compensated by cohesive controllers used for utility grid side voltage source converter (GVSC) and machine side VSC (MVSC). The switching controls and the reconfigurability of the μ-grid are addressed on imperative aspects of improving power quality (PQ), power reliability, nonlinear load compensation and economic utilization of resources. The nonlinear load compensation and PQ enhancement are achieved by executing modified version of the adaptive filtering technique including “momentum” based least mean square (MLMS) control technique, utilized for providing the switching control signals to the GVSC. It utilizes two preceding gradient weights for obtaining updated weight thereby improving the convergence rate and overcoming the limitation of conventional control of the same family. The MVSC acquires its switching signals from conventional vector control scheme and the encoderless estimation of speed and rotor position of the synchronous generator (SG) driven by wind turbine through back electromotive force control technique. The external environmental disturbances are overcome by utilizing perturb and observe (P&O) maximum power point (MPP) for wind optimal power extraction and adaptive P&O with variable perturbation step size for solar MPP estimation. Test results are obtained from the laboratory prototype under steady state and dynamic conditions including altering wind speed, intermittent solar insolation and variable load conditions. The PQ issues are addressed and investigated successfully.

The energy poverty in rural areas is due to the intermittent power supply from the existing utility. The proposed remotely located wind- solar photovoltaic (PV) array and battery energy storage (BES) supported microgrid, intends to overcome the uncertainty of the renewable power generation by compensating power quality (PQ) disturbances at the point of common coupling (PCC). Robust normalized mixed norm (RNMN) adaptive algorithm filters the load current component to remove the harmonics pertaining due to nonlinear load currents and improves the voltage profile at PCC. It allows the connection of sensitive loads without affecting their life and applicability at PCC. RNMN algorithm provides enhanced convergence rate as well as it reduces the steady state error effectively. BES controlled by a bidirectional DC-DC converter (BDC), ensures power supply to the critical loads during scarce generation by renewables resources. Proportional resonant (PR) controller provides superior performance over conventional proportional integral (PI) controller while dealing with the sinusoidal signals. Rejection of DC offset with effective harmonics elimination, is provided by the improved second order generalized integrator-phase locked loop (ISOGI-PLL). The speed regulation of the synchronous generator (SG) driven by a wind turbine is achieved by sensorless field oriented control (FOC) technique. The maximum power point (MPP) of each renewable resource, is attained by individual implementation of perturb and observe (P&O) scheme. The power sustainability is provided to the limited reach microgrid while overcoming the issues of load curtailment and PQ. Test results obtained on a developed prototype, demonstrate the applicability of the control algorithms promising solution in controlling the intermittency and fluctuations related complex issues faced by the remotely located microgrid.

A new topology comprising of wind turbine driven synchronous generator (SG) and solar photovoltaic (PV) array for renewable energy harvesting, is proposed in this work. The stochastic inputs for proposed system, are agitated by the nonlinear time dependent parameters such as variable wind speed and changing solar insolation. The speed variations are absorbed using back to back interfaced power electronic converters (PECs) namely synchronous generator side converter (SGC) and utility grid side converter (UGC) with a common DC link where solar PV array is tied directly. The power injection into the utility grid, is levelled by the optimal utilization of PECs. The SGC uses vector control (VC) for speed control of SG and maintains unity power factor (UPF) at stator terminals. UGC acquires its switching pulses with proper application of least mean mixed norm (LMMN) control technique. The new application of LMMN control scheme is used for harmonics compensation and fundamental load component extraction. The DC link voltage is regulated using proportional integral (PI) controller. A prototype is developed and tested under different conditions of sudden changes in load, wind velocity variations as well as under varying solar PV insolation. The power sharing scheme proves to be effective. The power quality (PQ) issues are also addressed and mitigated effectively. The performance is exhibited for the validation of the proposed system and its control.