This paper presents an inclusive review of the cyber-physical (CP) attacks, vulnerabilities, mitigation approaches on the power electronics and the security challenges for the smart grid applications. With the rapid evolution of the physical systems in the power electronics applications for interfacing renewable energy sources that incorporate with cyber frameworks, the cyber threats have a critical impact on the smart grid performance. Due to the existence of electronic devices in the smart grid applications, which are interconnected through communication networks, these networks may be subjected to severe cyber-attacks by hackers. If this occurs, the digital controllers can be physically isolated from the control loop. Therefore, the cyber-physical systems (CPSs) in the power electronic systems employed in the smart grid need special treatment and security. In this paper, an overview of the power electronics systems security on the networked smart grid from the CP perception, as well as then emphases on prominent CP attack patterns with substantial influence on the power electronics components operation along with analogous defense solutions. Furthermore, appraisal of the CPS threats attacks mitigation approaches, and encounters along the smart grid applications are discussed. Finally, the paper concludes with upcoming trends and challenges in CP security in the smart grid applications.

This paper introduces a multifunction interactive PV system that has the ability to feed a nonlinear local load in either grid-tied topology (GTT) or off-grid topology (OGT) and transits between the two topologies are seamless. The interactive PV system utilizes a sliding Fourier transform-based phase-locked loop (SFT-PLL) as an adaptive and robust control technique for extracting the fundamental load current. Further, the SFT-PLL is also used to synchronize the inverter output voltage with the grid during the GTT. The proposed synchronization technique has a superior immunity to the weak grid problems. The SFT-PLL based control technique has a very good ability to mitigate the nonlinear load harmonics and to deliver active current to the grid with a unity power factor. Moreover, the proposed control technique is able to keep a balanced grid current when the connected load is unbalanced whether the PV source is available or not. The DC-link voltage is controlled by the controller of the voltage source inverter (VSI) during GTT. During the OGT, the AC load voltage is regulated by the VSI controller while the DC-link voltage is regulated by the boost converter controller to satisfy the power requirements of the connected load. The simulation and experimental results show the effectiveness of the proposed control technique in feeding a balanced current with THD adheres to the IEEE-519 standard at different operating conditions. The performance of the proposed method is compared with recently published adaptive filtering techniques to show its effectiveness especially when the load current has a DC-offset.

This paper presents the design and implementation of a novel low-cost speed sensorless control technique for a permanent magnet assisted synchronous reluctance motor (PMa-SynRM). A robust adaptive speed (RAS) observer is designed for estimating the rotor speed and position, respectively. The RAS observer estimates the PMa-SynRM speed and position from the back electromotive force (BEMF) space-vector determination without voltage sensors by using the reference voltages issued from the current controllers instead of the actual ones. The novelty of the proposed RAS estimation technique is the adaptation of the feedback error of the actual values. Thus, the proposed observer structure promises a high degree of robustness against PMa-SynRM parameter change in the sensitivity analysis presented in this paper. The dynamic model and experimental realizations of the proposed control technique are introduced. A 6-kW PMa-SynRM drive test setup is constructed including dSPACE 1104 as the control heart of the proposed system. The hardware-in-the-loop of Typhoon HIL 402 is used to experimentally emulate the PMa-SynRM and the voltage source inverter connected to a dSPACE MicroLabBox. The proposed RAS observer robustness is evaluated using HIL model and experimental results under different conditions. A comparative experimental analysis between the proposed RAS and Luenberger observers has been performed.

This article presents the block control (BC) approach combined with the direct torque control (DTC) through employing a model reference adaptive system (MRAS) based on the super-twisting sliding-mode (STSM) speed estimator of a six-phase induction motor (6PIM) for ship propulsion application. The BC is a robust speed controller that is employed for regulating the 6PIM speed. The closed-loop approach is designed in an αβ -reference frame as well as is based on the linearization BC approach. The flux estimator is based on the super-twisting technique that is a second-order sliding-mode approach. This observer is utilized as a reference model throughout the MRAS-based speed estimator for discarding the chattering problem of the conventional sliding-mode technique. Two STSM controllers are used for controlling the torque along with the stator flux and improving the drive system performance throughout external load disruptions. Furthermore, the STSM estimator estimates the torque and stator flux in a robust response with discarding the chattering problem. The proposed MRAS-based STSM speed estimator performance is investigated experimentally for the 750-W 6PIM as well as compared with the traditional DTC approach throughout various speed references, load disruptions, and low-speed command/low loading torque conditions.