We review the most common topology of multi-level inverters. As is known, the conventional inverters are utilized to create an alternating current (AC) source from a direct current (DC) source. The two-level inverter provides various output voltages [(Vdc/2) and (−Vdc/2)] of the load. It is a successive method, but it makes the harmonic distortion of the output side, Electromagnetic interference (EMI), and high dv/dt. We solve this problem by constructing the sinusoidal voltage waveform. This is achieved by a “multilevel inverter” (MLI). The multilevel inverter creates the output voltage with multiple DC voltages as inputs. Many voltage levels are combined to produce a smoother waveform. During the last decade, the multilevel inverter has become very popular in medium and high-power applications with some advantages, such as the reduced power dissipation of switching elements, low harmonics, and low EMIs. We introduce the information about several multilevel inverters such as the diode-clamped multilevel inverter (DC-MLI), cascaded H-bridge multilevel inverter (CHB-MLI), and flying-capacitor multilevel inverter (FC-MLI) with Power systems CAD (PSCAD) simulation. It is shown that THD is 28.88% in three level FC-MLI while THD is 18.56% in five level topology. Therefore, we can decrease the total harmonic distortion adopting the higher-level topology.

The modular multilevel converter (MMC) has been prominently used in medium- and high-power applications. This paper presents the control of output and circulating current of MMC using sliding mode control (SMC). The design of the proposed controller and the relation between control parameters and validity condition are based on the system dynamics. The proposed designed controller enables the system to track its reference values. The controller is designed to control both output current and circulating current along with suppression of second harmonics contents in circulating current. Furthermore, the capacitor voltage and energy of the converter are also regulated. The control of output current is carried out in $dq$ -axis as well as in $\alpha \beta -axis$ with first-order switching law. However, a second-order switching law-based super twisting algorithm is used for controlling circulating current and suppression of its second harmonics contents. The stability of the controlled system is numerically calculated and verified by Lyapunov stability conditions. Moreover, the simulation results of the proposed controller are critically compared with the conventional proportional resonant (PR) controller to verify the effectiveness of the proposed control strategy. The proposed controller attains faster dynamic response and minimizes steady-state error comparatively. The simulation of the MMC model is carried out in MATLAB/Simulink.

This paper explores the potential of Digital Twin (DT) technology for Permanent Magnet Synchronous Motors (PMSMs) and establishes a foundation for its modeling and applications. While DTs have been widely applied in complex systems and simulation software, their use in electric motors, especially PMSMs, remains limited. This study examines physics-based, data-driven, and hybrid modeling approaches and evaluates their feasibility for real-time simulation, fault detection, and predictive maintenance. It also identifies key challenges such as computational demands, data integration, and the lack of standardized frameworks. By assessing current developments and outlining future directions, this work provides insights into how DTs can be implemented for PMSMs and drive advancements in industrial applications.

In sustainable energy applications, standalone solar power systems are mostly preferred for self-powered energy zones. In all standalone renewable power systems, batteries are still preferred as the common energy storage device. On the other hand, batteries are not applicable for high peak power demand applications because of their low power density. A supercapacitor is a preferable high-power density energy storage device for high peak power applications. A 2 kW, 50 kHz digital control dual active bridge isolated bi-directional dc-dc converter (DAB-IBDC) was developed for interfacing the supercapacitor bank in standalone solar power system. This paper proposes a blended SPS-ESPS digital control algorithm for a DAB-IBDC converter instead of using a traditional single-phase shift (SPS) control algorithm, which is commonly used for large input to output voltage varying applications. This proposed blended SPS-ESPS control algorithm achieved high power conversion efficiency during a large input to output voltage variation, over a traditional phase shift control algorithm by reducing the back-power flow and current stress in a circuit. This system also achieved maximum power point for solar modules and enhanced rapid charging-discharging for a supercapacitor bank. Both SPS and the blended SPS-ESPS control algorithms were verified experimentally using 2 kW DAB-IBDC topology implemented with standalone power system that combination of 2000 W input solar module and 158 Wh supercapacitor bank.

Interior permanent magnet synchronous motors (IPMSMs) are widely utilized due to their high power density. However, noise and vibration issues are often encountered in these motors. While researchers have extensively investigated individual aspects such as noise, vibration, and heat generation in PMSMs, there has been a lack of comprehensive studies examining the interrelationships among these factors. In this paper, a novel approach is proposed for predicting vibration by considering the radial force in the air gap as the exciting force, while also accounting for the changes in the permanent magnet (PM) characteristics caused by heat generation during motor operation. The method involves decomposing and identifying vibration components associated with each vibration mode and predicting noise based on the sound radiation efficiency of each mode. By constructing a vibration map based on current and temperature at a specific frequency, the components most affected by current variations and PM characteristics can be identified. This allows for the proposal of design improvements aimed at reducing vibration. Furthermore, by comparing the vibration map with the noise map, it is confirmed that vibration serves as a source of noise and influences its generation. However, it is found that vibration and noise are not strictly proportional. Overall, a comprehensive analysis of the correlations between vibration, noise, and other factors in IPMSMs is presented in this study. The proposed method and findings contribute to the understanding of the complex dynamics involved and provide valuable insights for the design of quieter and more efficient motor systems.

This paper discusses systematic efficiency considering the efficiency of both a motor and airflow in an inverter-driven single-phase brushless direct-current (BLDC) motor with two different lamination designs for a cordless vacuum cleaner. In other words, multi-physical lamination design has to be conducted, and hence, the shape and placement of a whole electromagnetic structure are investigated in terms of a tradeoff between the electrical and mechanical efficiencies. In this paper, a single-phase BLDC motor for cordless vacuum cleaners is designed to satisfy starting and continuous torques by means of asymmetric air gap, and fluid analysis is performed to determine which shape of a single-phase BLDC motor has better system efficiency. The prototype of a single-phase BLDC motor has been tested, and the speed of the operation is ranged from 84468 r/min up to the rated speed of 100020 r/min. The motor efficiency of 94.7% has been measured to verify a good match with the estimated efficiency of 94.5%.