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This article presents a multiobjective control scheme for a bidirectional interlinking converter (ILC) of renewable energy based ac–dc hybrid microgrid. The prime focus of the power management algorithm is to feed the ac loads, and dc loads from ac source, and photovoltaic battery energy storage (BES), respectively. The second objective is to utilize the solar power to maximum capacity, by feeding it to dc load, BES, and ac load, in the given order of priority. The ac and dc subgrids operate independently, while supporting each other in case of overloading/underloading, thus reducing the amount of power reserve required in each, and eliminating the need of dump loads. The ANFIS-MN-based power quality control is integrated in order to ensure the total harmonics distortion of ac source current remains below 5% as per IEEE 519 standard, irrespective of the nature of load connected. In addition, the ILC control prevents any negative sequence currents from entering the ac source, even if there is any open circuit fault leading to unbalanced loading on the three phases. The performance of ANFIS-MN-based ILC control is demonstrated to be superior when compared with the conventional and contemporary techniques under different scenarios. [ABSTRACT FROM AUTHOR]

Developing a robust and reliable high-voltage (HV) pulse power system (PPS) is essential for the characterization and testing of microwave tubes and industrial applications. This paper presents the design, simulation, and implementation of a modular and versatile high-voltage pulse power supply used in microwave device characterization and testing. A microcontroller-based digitally controlled pulse generation unit is also developed to generate the trigger pulses for high-voltage switching modules to control the turn-ON and turn-OFF of the switching devices. The digitally controlled pulse generation unit provides better resolution of pulse width, pulse repetition frequency, and system protection over the entire range of operations. The pulse generation and control circuit controls the pulse repetition frequency (PRF) and pulse wide (PW). The PRF and PW can be varied from 100 to 1000 Hz and 10 to 100 µs, respectively. The experimental prototype with ten series-connected high-voltage modules is connected to achieve a 25 kV pulsed output voltage. The experimental results of HV-PPS on a resistive dummy load and 5 GHz klystron tube are presented in this work. [ABSTRACT FROM AUTHOR]

In this article, islanding detection, control, grid synchronization, and power share techniques have been considered for the seamless operation of ac microgrid in grid-connected mode, islanded mode, and during the transition between both modes. A master–slave organization coordinates the power distribution among microgrid sources. The control scheme of each source is designed with a nested loop robust linear quadratic regulator and mixed $H_{2}/H_{\infty }$ optimal controller. The islanding detection algorithm is developed with synchro-extraction transform and optimal support vector machine (OSVM). An optimal linear Kalman filter-based synchronous reference frame phase locked loop (OLKF-SRFPLL) method is considered for the reconnecting of the microgrid to the utility grid. For optimal parameter tuning in the OSVM and LKF-SRFPLL methods, a particle swarm optimization technique is used. The seamless operation of the proposed ac microgrid system is verified in MATLAB/SIMULINK, and the practical feasibility is verified with an experimental photo-type setup and dSPACE 1202 control kit. Simulation and experimental results are presented to illustrate the seamless operation of the proposed ac microgrid system. [ABSTRACT FROM AUTHOR]

In this article, multiple parallel photovoltaic (PV) inverters based microgrid is developed to enhance the reliability and accessibility of electricity in remote areas. A self-adaptive control strategy is presented for a microgrid to ensure a seamless transition between the islanded mode (IAM) and grid-connected mode (GCM) of operation with a proportional power sharing. This microgrid consists of two solar PV inverters based on local distributed generation (DG) units. Each PV-inverter unit feeds an active power to support local loads and the power demand of each local load is shared between respective DG units and microgrid. The PV-battery-interfaced main unit with a self-adaptive control strategy in parallel with a PV array supported unit-2 is considered to operate in the IAM and GCM of operation. The control strategy achieves transient free operation during load disturbances, power variation at the PV array side, and off-grid operation. Moreover, the microgrid ensures high-quality performance at the point of common coupling and provides the seamless transition between GCM and IAM to guarantee a continuous power to critical loads. The microgrid simulation and experimental results are presented under various operating conditions, such as load variation, intermittent power generation, and automated mode transition between GCM and IAM. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) is a primitive evolutionary mechanism developed to escape incorporation of foreign genetic material. siRNA has been instrumental in achieving the therapeutic potential of RNAi by theoretically silencing any gene of interest in a reversible and sequence‐specific manner. Extrinsically administered siRNA generally needs a delivery vehicle to span across different physiological barriers and load into the RISC complex in the cytoplasm in its functional form to show its efficacy. This review discusses the designing principles and examples of different classes of delivery vehicles that have proved to be efficient in RNAi therapeutics. We also briefly discuss the role of RNAi therapeutics in genetic and rare diseases, epigenetic modifications, immunomodulation and combination modality to inch closer in creating a personalized therapy for metastatic cancer. At the end, we present, strategies and look into the opportunities to develop efficient delivery vehicles for RNAi which can be translated into clinics. [ABSTRACT FROM AUTHOR]

Nanotherapy has emerged as an improved anticancer therapeutic strategy to circumvent the harmful side effects of chemotherapy. It has been proven to be beneficial to offer multiple advantages, including their capacity to carry different therapeutic agents, longer circulation time and increased therapeutic index with reduced toxicity. Over time, nanotherapy evolved in terms of their designing strategies like geometry, size, composition or chemistry to circumvent the biological barriers. Multifunctional nanoscale materials are widely used as molecular transporter for delivering therapeutics and imaging agents. Nanomedicine involving multi-component chemotherapeutic drug-based combination therapy has been found to be an improved promising approach to increase the efficacy of cancer treatment. Next-generation nanomedicine has also utilized and combined immunotherapy to increase its therapeutic efficacy. It helps in targeting tumor immune response sparing the healthy systemic immune function. In this review, we have summarized the progress of nanotechnology in terms of nanoparticle designing and targeting cancer. We have also discussed its further applications in combination therapy and cancer immunotherapy. Integrating patient-specific proteomics and biomarker based information and harnessing clinically safe nanotechnology, the development of precision nanomedicine could revolutionize the effective cancer therapy. [ABSTRACT FROM AUTHOR]

With increased penetration of renewable power and the nonlinear loads in the distributed generation (DG) systems, increased power quality concerns are exhibited in the active distribution networks, especially the challenges associated with the current and voltage harmonics in the system. Various conventional harmonic compensation techniques are developed for voltage-controlled DG inverters in past, majority involve either multiple proportional-integral (PI) or proportional-resonant (PR) controllers in eliminating grid current harmonics. The current-controlled inverters, on the other hand, are not preferred in industrial applications, accounting to their wide variations in the switching frequency. A novel and adaptive harmonic voltage control is developed here, for voltage-controlled DG inverters, which neither uses any PI regulators nor imposes stability issues associated with nonideal implementation of infinite gains of PR controllers. Interestingly, the developed control logic can be used for DG inverters, both in grid-connected and off-grid operational modes. Furthermore, this strategy allows a network operator to use this as an additional supplement that can be enabled/disabled as per the network requirement. The control logic exploits the property of an optimal-switching-vector controller, i.e., accurate output voltage tracking. Simulations results demonstrate the effectiveness of the controller, to suppress grid current harmonics and load voltage harmonics in grid-interfaced (GI) and off-grid modes, respectively, ultimately satisfying the mandatory IEEE standard-1547. Experimental results verify the viability of the controller for practical applications. [ABSTRACT FROM AUTHOR]

This article presents an enhanced power quality solar photovoltaic (PV) inverter enabling common-mode leakage current elimination. A three-phase transformerless solar energy conversion system is considered here, which, along with peak active-power production from PV array, ensures different power quality improvement capabilities such as grid current harmonics mitigation, grid currents balancing while also offering the grid reactive power support. Unlike conventional power quality inverters, this strategy is robust with respect to abnormalities in grid voltages at far radial ends, and does not compromise with the leakage currents caused by parasitic capacitance of PV array with ground. Common practice in the PV inverter power quality control is to neglect the PV leakage currents; however, they considerably affect the system performance by deteriorating the power quality and causing the safety issues of operating personnel. The standards VDE-00126 and NB/T-32004, therefore, compel the transformerless PV systems to operate with leakage current under 300 mA range. Various simulation and test results show the satisfactory performance of the presented strategy, even under various grid-side abnormalities. The comparative analysis with the state-of-the-art techniques shows the effectiveness of the strategy. Under all test conditions, the harmonics in grid currents are observed within limits as per the IEEE-519 and IEC-61727 standards, whereas the PV leakage currents are maintained well within the range recommended by VDE-00126 standard. [ABSTRACT FROM AUTHOR]

This paper uses the recently proposed H[infinity]-learning method, for updating the parameter of the radial basis function neural network (RBFNN) used as a control scheme for the unified power flow controller (UPFC) to improve the transient stability performance of a multimachine power system. The RBFNN uses a single neuron architecture whose input is proportional to the difference in error and the updating of its parameters is carried via a proportional value of the error. Also, the coefficients of the difference of error, error, and auxiliary signal used for improving damping performance are depicted by a genetic algorithm. The performance of the newly designed controller is evaluated in a four-machine power system subjected to different types of disturbances. The newly designed single-neuron RBFNN-based UPFC exhibits better damping performance compared to the conventional PID as well as the extended Kalman filter (EKF) updating-based RBFNN scheme, making the unstable cases stable. Its simple architecture reduces the computational burden, thereby making it attractive for real-time implementation. Also, all the machines are being equipped with the conventional power system stabilizer (PSS) to study the coordinated effect of UPFC and PSS in the system. Index Terms--Controller, neural network, power system, transient stability, unified power flow controller (UPFC).

This article aims to develop a solar- battery energy storage (BES) based system, which ensures an uninterruptable supply to loads irrespective of availability of the grid. This system comprises of a solar photovoltaic (PV) array, a BES, the grid and local residential loads. A new control is implemented such that the active power demand of residential loads, is fed from the PV array, a BES unit and the utility grid. In this system, the power control operates in different power modes, which delivers the benefits to the end users with an integration of BES and an excess of PV array power, which is sold back to the grid. For this, an effective control logic is developed for the grid tied voltage source converter. Moreover, this system deals with the issue of an integrating power quality enhancement along with the power generation from the solar PV source. The cascaded delayed signal cancellation based phase locked loop is implemented for grid synchronization during the grid voltage distortion. The developed control is easily implemented in a real time controller (dSPACE-1202). Test results validate the performance of the implemented control in different operating conditions such as varying solar power generation, load variations and unavailability of the grid. [ABSTRACT FROM AUTHOR]

The dual active bridge (DAB) converters have the capability of handling high power in compact form and it is one of the key elements for interconnecting different dc microgrid clusters. A DAB also offers bidirectional power transfer with galvanic isolation between two power buses of similar or different voltage levels, i.e., low voltage and high voltage buses. In microgrid applications, bus voltage regulation is necessary for an uninterrupted power flow and reliable operation of dc microgrids. Due to the galvanic isolation and modularity nature of a DAB, the output can be easily interconnected for efficient and reliable power sharing. In this article, taking the advantage of modularity property of the DAB, an efficient and improved power sharing scheme is developed to stabilize the bus voltage in microgrid applications. A robust bidirectional power sharing control strategy is developed between DABs from different high voltage buses to low voltage buses that improves the voltage stability. An advanced supervisory controller is designed by considering the nonlinearity and uncertainty that ensures stable dc bus voltage and reliable power sharing among DABs under different operating conditions. The controller is validated theoretically and a small-scale laboratory prototype is developed. The concept is verified experimentally at different possible scenarios. From theoretical and experimental results, it is found that the proposed DAB control provides excellent performance in terms of power sharing, dc-bus voltage regulation and power quality. [ABSTRACT FROM AUTHOR]

DC microgrids (DCMGs) are evolving into cyber-physical systems with advanced communication networks and computational methodologies, making them sensitive to cyber-attacks. These attacks can threaten the safe operation of a system. In this article, a virtual sensor-based framework is proposed for continuously monitoring and detecting malicious activities at the hardware level of a DCMG system. An adaptive state observer with a low computational burden is designed to estimate the voltage and current of a dc–dc converter. The proposed method considers the effects of cyber-attacks by injecting false data (FD) at targeted nodes in an attempt to affect the voltage regulation and current sharing by modifying the onboard voltage and current sensors. In the presented strategy, first, a DCMG is operated and controlled without any false data injecting attacks with different load conditions. Next, the DCMG is exposed to various cyber-attacks, and the output voltages and currents of dc–dc converters are estimated. Based on the error between the estimated and actual sensed signals, the cyber-attack is detected and corrected with the proposed framework. The proposed scheme is simple in design, efficient in operation, and easily implemented in a distributed control system. The effectiveness and robustness of the proposed method are illustrated by implementing it in real-time hardware using the LabView test bench by considering four dc systems (including a solar photovoltaic system) connected in a ringlike manner communicated via an ethernet-based local area network. [ABSTRACT FROM AUTHOR]

A time domain dynamic model of impedance has been developed in this work for online estimation of Thevenin’s equivalent impedance of a network seen from a bus. Although the time domain impedance (ratio of instantaneous AC voltage and current) is undefined in a period, a zone of definition and workability has been defined. Using the zone of definition, an observable dynamic model has been constructed. An algorithm is developed which uses the model along with a Kalman filter to estimate the Thevenin’s impedance. The algorithm takes the time domain instantaneous voltage and current of the bus as its input. Simulation bus data has been generated by EMTP/PSCAD and the algorithm has been developed in MATLAB. The model helps to successfully estimate the network Thevenin’s equivalent with better steady state and transient tracking ability than the frequency domain based DFT algorithm. The algorithm has been implemented in hardware using Opal-RT systems. [ABSTRACT FROM AUTHOR]

A reduced-order model of a converter-dominated microgrid system may not resemble its full-order system associated with uncertainties. This paper aims to provide a singular perturbation-based contraction framework for model order reduction in converter-dominated uncertain microgrid systems. For this purpose, the concerned microgrid system is modeled as a generalized multi-timescale system, and certain sufficient conditions are derived such that convergence between the trajectories of the uncertain full-order and the corresponding reduced-order model can be guaranteed. The contraction theory-based strategy also provides explicit parameter-dependent expressions for quantifying discrepancies. The derived results are utilized to analyze the inverter-based microgrid system’s convergence behavior and obtain uncertainty bounds on its parameters. Further, the effects of modeling uncertainties and different loading conditions on the reduced-order model’s validity are also discussed. It is observed that for any uncertainty associated with the microgrid parameters that are within the bounds of checkable conditions, the states of the reduced-order microgrid model converge to that of the uncertain full-order system. Further, it is also shown that the obtained discrepancy expressions are more precise than state of the art. [ABSTRACT FROM AUTHOR]

The increase in the numbers of electric vehicles (EVs) is seen as an upgrading of the existing vehicles for various reasons. This calls for an in‐depth analysis of the heart of these vehicles—the motor. A motor in an electric vehicle propulsion system is a crucial component that has the ability to affect the efficiency, weight, cost, reliability, power output and performance. Hence a detailed comparative study, that compares the existing types and topologies of various motors, is the need of the hour. The various motors that can be used in electric traction, namely DC, induction, switched reluctance, permanent magnet brushless AC motors and permanent magnet brushless DC motors, are reviewed in view of their capabilities with respect to EV propulsion. A detailed review is presented of existing motors and the application of power electronic techniques to EVs, and recommendations for some new designs of brushless DC motors. These include permanent magnet hybrid motors, permanent magnet spoke motors and permanent magnet inset motors. [ABSTRACT FROM AUTHOR]

This article proposes a computationally simple strategy by using a three-sample-based technique for a grid-connected inverter in a single-phase active distribution system. The proposed control is to improve the performance during varying grid conditions such as voltage sag, swell, and frequency swing. A comparative analysis between the proposed controller and the conventional second-order generalized integrator phase-locked loop (PLL) based controller for dynamic grid conditions in weak-grid scenario has been presented. Additionally, a frequency domain analysis via describing function method is used to model the dynamics of nonlinear hysteresis current controller to analyze the closed-loop stability of the system. Further validation of the proposed control algorithm is simulated in MATLAB/SIMULINK environment for various scenarios. To establish the effectiveness of the proposed approach in real time, the proposed control strategy is tested in a 1 kVA based experimental setup. [ABSTRACT FROM AUTHOR]

In this paper we propose a one-dimensional convolutional neural network (CNN)-based state of charge estimation algorithm for electric vehicles. The CNN is trained using two publicly available battery datasets. The influence of different types of noises on the estimation capabilities of the CNN model has been studied. Moreover, a transfer learning mechanism is proposed in order to make the developed algorithm generalize better and estimate with an acceptable accuracy when a battery with different chemical characteristics than the one used for training the model, is used. It has been observed that using transfer learning, the model can learn sufficiently well with significantly less amount of battery data. The proposed method fares well in terms of estimation accuracy, learning speed and generalization capability. [ABSTRACT FROM AUTHOR]