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The main contribution of this study is to propose a new rotor position observer with the approach of model reference adaptive system (MRAS) associated with the quantity of control winding (CW) power factor of the brushless doubly-fed induction generator (BDFIG) for sensorless voltage control target in stand-alone systems. The proposed observer relies on the field-orientation scheme of power winding (PW) side. The proposed sensorless methodology does not need any computation process with integration for obtaining the flux components. In addition, the new methodology can reduce the voltage sensors required for detecting the actual CW voltage quantities to be used in the calculations process of the proposed MRAS procedure by directly realizing the CW reference stationary voltages from the input path of SVPWM. This would ensure the simplicity of the suggested procedure for detecting the rotational position of the generator. The stability confirmation of the presented estimation method is analyzed and realized with the aid of technique of hyperstability concept and aided with the criteria of Popov's analysis. Moreover, the verification of robustness for the proposed observer is studied via uncertainty issues of machine parameters. Comprehensive simulation and experimental results are carried out to verify this method

In this article, a new supertwisting sliding mode direct thrust control (NSTSM-DTC) scheme is proposed to improve the dynamic response, robustness ability of the linear induction machine, and overall drive performance. First, a NSTSM algorithm is proposed and implemented in both electromagnetic thrust and primary flux-linkage control loops. The design aspects, implementation process, and stability analysis of the NSTSM based on the DTC method are fully investigated, which can effectively achieve faster dynamic response, smaller steady state speed tracking error, lower electromagnetic thrust ripple, and increase the system robustness against load variation in comparison to those of the conventional control methods. The proposed method is fully confirmed by the comprehensive simulations and experiments based on one prototype of 3 kW arc induction machine.

A novel sliding-mode-based extended state observer (SMESO) is proposed to improve the disturbance rejection ability and enhance the dynamic performance of permanent magnet synchronous motor drive systems. First, an extended state observer based on the fast terminal sliding-mode control (FTSMC) method is developed for better comparison, which can improve the robustness against load disturbances, finite time convergence, and get effective reduction of the chattering phenomenon. The SMESO-based FTSMC is then developed by using the SMESO to estimate the system total disturbance, and input the signal to a feed-forward compensation controller to further improve the system dynamic performance. The closed-loop stability analysis is conducted by using the Lyapunov stability function. The superior effectiveness of the proposed method is confirmed by comprehensive simulation and experiments.

Standalone rural microgrid (MG) systems are considered as a sustainable and economical solutions towards rural area electrifications. Specific control schemes are necessary to adopt for reliable and economic performance of these rural MGs. This study focuses on the optimal utilization of biomass potential considering specific applications of bio generator (BG) with BG-PV-WT-BSS and BG-PV-SMES based standalone rural MG systems. In the first case of the BG-PV-WT-BSS, the optimal sizing/selection of DGs of a rural MG has been proposed using the improved-MILP (I-MILP) approach. The objectives of this study were to minimize total net present cost (TNPC), the levelized cost of energy (LCOE) and GHG emissions. In the second case of BG-PV-SMES, the simulation model of the rural microgrid consisting of a variable speed bio generator (VSBG) and photovoltaic (PV) has been developed. Afterwards, a simplified EMS has been designed for the coordinated operation control of the distributed energy resources (DERs) in the rural MGs using MATLAB/Simulink® environment. For the DGs connected via power converter, FOSMC and FCS-MPC based coordinated control has been proposed in the simplified EMS. The purpose of the FOSMC and FCS-MPC based power converter is the improvement of the system performance (for instance power quality, regulated voltage and THD) under external disturbances. Simulation analysis shows the better operation of FOSMC and FCS-MPC under less THD and improved power quality.

In order to enhance the speed control performance of the permanent magnet synchronous motor (PMSM) with internal and external disturbances, a new adaptive terminal sliding mode reaching law (ATSMRL) is proposed with continuous fast terminal sliding mode control (CFTSMC). Firstly, the ATSMRL is presented with the aim of reducing the input control efforts, which can dynamically adopt all positive aspects in terms of the finite time convergence, high tracking precision, and reduction of the chattering in the control input of the system. Secondly, an extended sliding mode disturbance observer (ESMDO) is designed to estimate the total disturbances of the system, and then the estimated disturbance has been brought for the feed-forward compensation technique, which would enhance the disturbance rejection ability of the system. Afterwards, the close loop stability is validated by the Lyapunov function. Finally the comprehensive numerical and experimental analyses have been carried out to demonstrate the superiority of the ATSMRL method than those of conventional exponential sliding mode reaching law (ESMRL) and terminal sliding mode reaching law (TSMRL).