In this paper, the cyber-security of smart microgrids is thoroughly discussed. In smart grids, the cyber system and physical process are tightly coupled. Due to the cyber system’s vulnerabilities, any cyber incidents can have economic and physical impacts on their operations. In power electronics-intensive smart microgrids, cyber-attacks can have much more harmful and devastating effects on their operation and stability due to low inertia, especially in islanded operation. In this paper, the cyber–physical systems in smart microgrids are briefly studied. Then, the cyber-attacks on data availability, integrity, and confidentiality are discussed. Since a false data injection (FDI) attack that compromises the data integrity in the cyber/communication network is one of the most challenging threats for smart microgrids, it is investigated in detail in this paper. Such FDI attacks can target state estimation, voltage and frequency control, and smart microgrids’ protection systems. The economic and physical/technical impacts of the FDI attacks on smart microgrids are also reviewed in this paper. The defensive strategies against FDI attacks are classified into protection strategies, in which selected meter measurements are protected, and detection/mitigation strategies, based on either static or dynamic detection. In this paper, implementation examples of FDI attacks’ construction and detection/mitigation in smart microgrids are provided. Samples of recent cyber-security projects in the world, and critical cyber-security standards of smart grids, are presented. Finally, future trends of cyber-security in smart microgrids are discussed.

This paper presents a unified control strategy for parallel LCC-VSCs interlinking converters (IC)s in hybrid AC/DC grids. The parallel LCC-VSCs configuration takes advantage of the low cost of the LCC system as well as the bidirectional power flow capability of VSCs and offers an excellent option for lowering system costs with high performance. Moreover, drawbacks of the LCCs such as low power quality, reactive power consumption, and commutation failure can be addressed by using the parallel LCC-VSCs configuration with proper control and coordination. The proposed unified control system is developed by modifying the LCC's V-I graph to create a droop equivalent along with droop-based control of the VSCs. As a result, it provides voltage/frequency support for the AC and voltage support for the DC sub-grids in various operating conditions. In this paper, the performance of the proposed control strategy under different operation conditions is investigated. Case study results, with a realtime simulator, are provided to verify the effectiveness of the proposed control strategy.

This work presents a harmonics compensation control scheme for parallel LCC-VSCs interlinking converters (ICs) in a hybrid AC/DC network. The proposed technique addresses the harmonic issue of the LCC unit with higher performance and lower cost by taking advantage of parallel LCC-VSCs configuration. It is important to note that system stability and power quality are fundamental aspects of such a system. The mitigation method is designed for medium/high voltage converters with a low switching frequency, a common environment for the LCC-based units. The harmonics mitigation technique is designed to avoid any interference with the normal operation of the parallel LCC and VSCs in a hybrid AC/DC network. Furthermore, the reactive power consumption issue of the LCCs is also addressed. The proposed system is modelled in detail, and stability studies are conducted. Also, the controlling parameters design procedure is explained thoroughly, assuming proper stability is achieved. The peak current capacity of the VSCs for the anticipated harmonic orders and reactive power compensation is calculated. Eventually, the performance of the proposed control strategy under different operation conditions is investigated. Case study results with MATLAB Simulink and an experimental platform are provided to verify the effectiveness of the proposed control strategy.

This paper proposes a control scheme for line commutated converters (LCCs) to operate in parallel with voltage source converters (VSCs) in an AC/DC network. The proposed control strategy uses a droop equivalent control and precautionary measures for the LCC to work along with droop controlled VSCs. The paralleling VSCs with LCCs improves the LCC’s operation region beyond its conventional (V-I) graph mode. Also, the LCC’s resilience to commutation failure is enhanced. Improving the LCC’s control scheme leads to a unified control scheme, in which the AC sub-grid’s voltage and frequency and DC sub-grid’s voltage can be supported in all operating conditions. The operation principles and the system response to the AC and DC sub-grids’ disturbances are investigated. The fault response measures of the proposed system show increased stability and power quality. In the proposed control scheme, proper solutions for the operation limits, such as commutation failure and reactive power compensation are provided. The performance of the proposed control scheme is tested with realtime simulator in different operating conditions, and its stability and accuracy are verified.

While both line commutated converters (LCCs) and voltage source converters (VSCs) have been adopted in AC/DC grids, they are mostly used individually despite some point-to-point DC transmission. The combination of both technologies as a single interlinking converter (IC) unit in an AC/DC grid can bring advantages such as capacity expansion, bidirectional power flow, reactive power support and harmonics compensation. For such a parallel LCC-VSC unit, a suitable control scheme and careful control parameters design are important to ensure the system can maintain the above advantages in different operation modes. In this paper, the control scheme and parameter design for a parallel LCC-VSC unit for use in an AC/DC grid is conducted with a focus on capacity expansion scenario, where a unified control scheme that reserves most of the original LCC terminal’s control while also smoothly incorporates the VSC operation is considered. The operation states of a hybrid AC/DC network are modelled. The proposed unified control scheme is considered for each state for the stability study. Then, a set of control parameters for the unified control scheme suitable for all operation states with good dynamics and stability is designed. Real-time simulations and experiments are conducted to verify the design and study.

This study presents a mixed-integer nonlinear programming (MINLP) framework to optimize the allocation of electric vehicle charging stations (EVCSs) in existing indoor parking facilities. The model minimizes total life-cycle cost by jointly determining charger types and placements while accounting for spatial feasibility and investment constraints. A hybrid search method that combines complete enumeration with dynamic programming is applied to identify the least-cost configuration within geometric and electrical limitations. The results show that configurations combining dual- and quad-port chargers outperform single-port layouts by reducing redundant electrical and installation costs. The analysis confirms that integrating life-cycle costing with spatial feasibility yields a practical decision-support tool for property owners seeking to expand charging capacity within existing facilities. Overall, the framework demonstrates that cost-efficient retrofitting of EV charging infrastructure can be achieved without additional land development, supporting broader sustainability objectives and promoting low-carbon mobility. Future research will extend the model to multiple facility layouts and incorporate sensitivity and uncertainty analyses to evaluate robustness under varying geometric and economic conditions. The findings of this paper provide a practical foundation for future planning studies and demonstrate how cost-optimized retrofit strategies can support the scalable expansion of EV charging infrastructure in existing facilities.