2026-03-01
A. Nayli, S. Guizani, F. Ben Ammar
Introduction . The machine-converter system is a prevalent and essential configuration, widely used not only in variable-speed industrial drive applications, but also in high-tech transportation and power fields. Problem. Conventional drive systems, particularly those supplied by standard 2-level inverters, face major challenges regarding the enhancement of their dynamic performance and drive availability. To overcome these limitations, a solution involves utilizing the open-end stator winding induction machine associated with cascaded 2-level inverter topologies. The goal of this work is to improve the availability of the drive system by increasing its degrees of freedom through the association of an open-end winding induction machine by two cascaded 2-level inverters. Methodology. The mathematical modeling of this machine is presented and validated using MATLAB/Simulink. To evaluate the machine’s performance, it is first powered by two cascaded 2-level inverters and subsequently by three cascaded 2-level inverters. Following this initial evaluation, the machine is then fed by two cascaded 2-level inverters operating in degraded mode. This analysis features different failure configurations, and the specific operational conditions that must be respected. Results. This topology enhances dynamic performances and enables effective power segmentation as well as a degraded mode operation. These benefits are confirmed by the simulation results . The scientific novelty is based on demonstrating the effectiveness of degraded mode control, which gives the machine-cascaded inverters topology a superior advantage in terms of reliability and performances . Practical value. This topology provides a highly reliable and fault-tolerant drive solution, ensuring better performance during normal operation and better availability after an inverter failure. References 15, tables 1, figures 24.
2026-03-01
I. I. Alnaib, A. N. Alsammak
Problem. Electrical distribution networks are plagued by power quality problems, which have a negative impact on sensitive electrical loads. These problems include reactive current, low power factor on the load side, and voltage harmonics, voltage sags and voltage swells on the grid voltage side. To address these issues, a unified power quality conditioner (UPQC) that combines shunt and series compensators is suggested . The goal of the work is to implement a UPQC integrated with a photovoltaic (PV) system to mitigate power quality problems in the power system, and boosting the grid supply through power injection from the PV system. Methodology. One of the less complex and effective ways to improve the grid’s voltage quality is by using the unit vector template generation (UVTG) strategy as the composition technique (UPQC-P) through the UPQC series compensator. The synchronous reference frame (SRF) strategy through the UPQC shunt compensator to improve the current quality on the load side is used. To further optimize the SRF strategy, it is used the snake optimization (SO) to find the optimal values for the PI controller’s parameters . Results. The UPQC-PV is used to mitigation the power quality issues in the grid and loads by UVTG and SRF techniques in series and shunt compensators, respectively. Scientific novelty . The composition technique (UPQC-P) through a series compensator and uses the SO for tuning the PI controller in the shunt compensator. Practical value. This study reduces the total harmonic distortion (THD) in the load voltage to 0.57 %, while the THD in the grid voltage remains at 10 %. It restores the load voltage to its reference value of 230 V during voltage sags (down to 161 V) and swells (up to 300 V) in the grid. Additionally, it mitigates the low power factor on the load side (0.707 lagging) to achieve a unity power factor in grid current, balances the unbalanced load current to a balanced grid current, and enhances grid stability by injecting power from the PV system into the grid . References 33, table 3, figures 7.
2026-03-01
M. Kamal, M. F. Ullah, N. Anwar, A. I. Hussein
Introduction. This study applies hybrid metaheuristic optimization techniques to intelligently schedule household loads, ensuring a balance between cost reduction, comfort and grid stability in smart homes. Problem. The growing gap between energy demand and supply leads to high electricity costs, increased appliance waiting times, a higher peak-to-average ratio (PAR) and reduced user comfort. Efficient management of residential energy consumption remains a major challenge for sustainable smart grid operation. Goal. This study aims to minimize electricity costs, reduce PAR and enhance user comfort by optimally scheduling household appliances and shifting loads from peak hours to off-peak hours. Methodology. A demand-side management approach is implemented using 5 metaheuristic optimization algorithms: harmony search algorithm (HSA), flower pollination algorithm (FPA), hybrid harmony flower pollination algorithm (HFPA), multiverse optimization algorithm (MVO) and cuckoo search algorithm (CSA). Real-time pricing is employed as the pricing model. MATLAB simulations were conducted for 10, 30 and 50 smart homes, each comprising 15 residential loads categorized as controllable or base appliances. Results. Simulation results demonstrate that the proposed HFPA consistently outperforms HSA, FPA, MVO and CSA across all tested scenarios, achieving notable reductions in electricity cost and PAR while minimizing appliance waiting times. Scientific novelty . The hybrid HFPA effectively combines the strengths of HSA and FPA, balancing exploration and exploitation to deliver superior performance in multi-objective optimization for home energy management systems. Practical value. The proposed HFPA achieved up to 19.86 % reduction in electricity cost and 81.03 % minimization in PAR, significantly enhancing user comfort and operational efficiency. The method can be further extended for integration with renewable energy sources and machine learning-based predictive control systems. References 32, tables 6, figures 5.
2026-03-01
A. N. Patel, T. H. Panchal
Introduction. Cogging torque deteriorates the torque quality of surface permanent magnet brushless DC (PMBLDC) motors. Problem. Reducing cogging torque is indispensable for performance upgradation of PMBLDC motors; hence, it is an important issue for motor designers. Goal. This paper presents a slot opening shift approach to reduce the cogging torque of radial flux surface PMBLDC motors. Methodology. A 200 W, 1000 rpm radial flux surface PMBLDC motor is first designed based on different assumed design variables and is treated as a reference model. The parallel stator teeth are uniformly distributed along the stator periphery, and the slot opening is considered in the middle position in the reference design. The cogging torque of the reference design is obtained from simulation and electromagnetic analysis. Results. A series of finite element simulations are performed to examine the impact of design upgradation on the cogging torque of the surface PMBLDC motor. It is observed that the peak-to-peak cogging torque is reduced by 44.5 %. Scientific novelty. The design is enhanced by applying slot opening shift to stator slots. The slot opening is shifted in an anticlockwise direction, and subsequently, the cogging torque waveform is determined for the upgraded motor from finite element modelling and analysis. Practical value . Research has revealed that this technique is effective in reducing cogging torque, and it can also be applied to other topologies of permanent magnet motors. References 23, tables 2, figures 12.