The hybrid neutral-point-clamped (NPC) dual-active-bridge (DAB) topology aims to mitigate the excessive voltage and current stresses experienced by semiconductor devices in high-power applications. The hybrid duty ratio phase-shift modulation (PSM) achieves improved efficiency performance. However, previous studies have not extensively explored the intricacies of the switching characteristics. In this paper, a comprehensive analysis of the switching behavior is given, particularly focusing on the turn-off loss of Si IGBTs, based on relevant formulas and switching waveforms. To enhance clarity, a comparative analysis is conducted, contrasting the obtained results with those obtained from the triple-phase-shift (TPS) modulation method. Simulations and experiments are conducted for validation of the theoretical analysis.

The common-mode (CM) choke is critical integral part of an electromagnetic interference (EMI) filter. An accurate electrical model of the CM choke is crucial to simulate and evaluate the EMI filter performance with confidence. Numerical simulation has emerged as a feasible solution to realize the above-mentioned objectives without the presence of physical products, and thus reducing the trial-and-error process and achieving the choke design speedups. This paper proposes a comprehensive process for the characterization and modeling of single-phase CM chokes based on finite-element analysis (FEA). By extracting the transmission parameters through 3-D model of choke, both impedance magnitudes and phases of its CM or differential-mode (DM) can be collected. These impedances will then be used to derive the behavioral model. The results are validated experimentally with good agreement up to 100 MHz.

Single-phase common-mode chokes (CMCs) are key components in electromagnetic interference (EMI) filters to mitigate conducted emissions caused by the switching power converters. Finite-element analysis (FEA) has been adopted as one of the simulation tools to model a CMC for the extraction of its impedance frequency response. Most literatures focus on the extraction of impedance magnitude, but few explore the analysis of the impedance phase information. This article investigates the phase sensitivity of FEA modelled single-phase CMCs, which reveals the impact of various design parameters on simulation results at frequencies up to 100 MHz.

In order to enhance the diagnosis of turn-to-turn short circuit (TTSC) fault based on machine learning (ML), a novel method to decouple the demagnetization characteristics due to TTSC fault effect on magnet to improve the data integrity is presented in this article. The updated knee point of the magnet based on magnet temperature is obtained in real-time and a fault indicator indicative of the initialization of irreversible demagnetization is used to decouple the influence of rotor MMF from the magnetic field energy stored in the air-gap. An extensive set of data is obtained from analytical modelling of permanent magnet synchronous machine (PMSM) with TTSC fault based on winding function approach. The model fidelity is increased by incorporating the TTSC fault effect on magnet as a look-up-table obtained from finite element analysis. In addition to the simulation data, experimental data of PMSM with TTSC fault are used to train the machine learning algorithms. The results confirm that data integrity is improved and time-domain signal analysis are sufficient for training and diagnosis of TTSC fault based on ML algorithms.

Marine electrification offers an excellent solution towards curbing the emission of greenhouse gases. This work proposes a single-phase self-regulated switched capacitor multilevel (SCML) voltage source inverter (VSI) for maritime electrification. The proposed SCML-VSI utilizes 18 power electronic switches (PESs), 4 capacitors and 2 DC voltage sources for generating a 49-Level output voltage. The proposed SCML-VSI topology requires only 10 driver circuits as 16 PESs operate in complementary fashion. The Nearest level control strategy is utilized for the generation of switching pulses. The proposed 49-Level SCML-VSI can be extended for a higher number of output voltage levels through cascading of ternary units. Performance of the proposed SCML-VSI is realized through simulation studies using MATLAB® Simulink platform under different operating conditions.

This paper introduces a novel physics-informed pattern recognition (PIPR) method for open-circuit fault detection in inverters. The proposed method unfolds in three stages: model analysis, offline training, and online validation. In the first stage, we construct an analytical model of power converters. This model is subsequently used to derive fault diagnosis variables. This step is followed by the collection of training samples via simulations. The gathered samples are then fed into pattern recognition neural networks, a process enabled by the prior extraction of model information. This architecture allows for efficient training of the neural network with fewer neurons and samples. The final stage involves the detection and diagnosis of faults by a well-trained online classifier. The robustness of the proposed PIPR method in dealing with unexpected conditions in classification problems shows its potential across diverse conditions.

This research paper focuses on coordinated operation scheduling of the condition-based maintenance and energy management of an all-electric ship (AES). The condition-based maintenance comprises of risk assessments, short-duration main-tenance, and condition monitoring of the critical components. The main objective of the proposed strategy is to minimize the fuel, emission, and maintenance cost of the generation and storage units by optimally scheduling the voyage, generation, and risk assessment periods while incorporating the additional information obtained from the condition monitoring equipment. The problem is formulated as a mixed-integer linear programming problem and the non-linear constraints are linearized to improve the computational efficiency. Based on the criticality and risk assessment of the affected units, the operation schedules are continuously updated. The proposed method is validated through a simulation study, and the results demonstrate the applicability and effectiveness of the proposed strategy for the future AES.

This paper proposes a coordinated energy dispatch of the multi-energy ship microgrid with the consideration of the thermal energy requirements of the refrigerated container system (reefer). The proposed combined electricity, cooling, and heating network consists of multiple energy sources (diesel generators, auxiliary electric boiler, auxiliary electric chiller, and gas turbine) and energy storage units (electrical and thermal storage). It aims to minimize the emission cost, the storage operating cost, and startup/shutdown cost of the generation units while maximizing their efficiency. With the help of the piece-wise linearization technique, the coordinated multi-energy dispatch model is formulated as a goal-based multi-objective mixed-integer linear programming problem that can be effectively solved by the commercial solvers. Goal programming (Priori approach) does not require the mapping of the Pareto-front or the solution space and hence saving additional computational power requirements. A case study is carried out to evaluate the effectiveness of the proposed dispatching scheme and the result indicates the improvement in dispatch flexibility by coordinating the electrical power generation with cooling and heating requirements.

The drive for more electric aircraft (MEA) architecture has resulted in the introduction of high power density electric machines for aircraft propulsion applications. The reliability of the electrical machines in such harsh environments is a challenge that is seldom addressed. The paper proposes, through simulation, the use of aging model to accurately estimate the lifetime of a machine with turn-to-turn short-circuit (TTSC) condition. The proposed aging model considers all the aging factors due to electrical, mechanical and thermal phenomena. The paper also puts forth a cumulative stress curve for various loading & environmental constraints and uses the stress curve with winding temperature to create an aging model to accurately predict and estimate the lifetime of the machine. A bottom-up approach through the developed model can be used to estimate the lifetime of the machine in real-time.

A coupled-inductor-based bidirectional Z-source breaker topology is introduced in this paper, which has the ability to detect and isolate the faulty section of the dc power system. Compared to existing topologies, the proposed topology utilizes a lower number of components and the coupled inductors reduce the footprint of the breaker. Analytical design equations are derived for the sizing of inductors and capacitor. Fault condition is analyzed to compute the essential criteria for the breaker to operate. Operation under step load and fault conditions are validated by simulation in both SPICE and MATLAB/Simulink environment.

The Vienna rectifier is an attractive converter solution due to the three-level voltage generation and its simple structure. When the Vienna rectifier operates with nonunity power factor, the reference voltage and the input current have different signs during some intervals around the current zero crossings. This creates low-frequency distortion in the current waveforms. One of the preferable methods to reduce this distortion is the zero sequence injection which, however, risks the converter entering into overmodulation. This paper analyses the above distortion and introduces the operation of the Vienna rectifier in two modes, which includes injecting a proper zero sequence and reactive power compensation. This allows the converter to operate in a wide range of power factors without constraining the modulation index. The required reactive current is obtained analytically from the instantaneous values of the converter at any operating point.

Dual active bridge (DAB) converter has become a promising solution to integrate batteries and renewable energies into DC microgrids (MG), which can reduce the number of power conversions. To improve the stability and robustness of DC microgrid, a particle swarm optimization based active disturbance rejection control (PSO-ADRC) approach is proposed and validated in a single-phase DAB topology. PSO method is employed as an automatic tune mechanism to update the parameters of the ADRC controller in real-time. The simulations show that the control method is robust against parameter variations and external disturbance.

This paper proposes a four-phase mutually coupled switched reluctance machine (MCSRM) arrangement with single pulse current control strategy, targeting performance improvements of both the machine and the power converter. Previously published works on MCSRM have focused only on machine performance while neglecting the power converters. Designs and comparative studies have been carried out among conventional switched reluctance machine (CSRM), full pitch MCSRM, short pitch MCSRM and single pulse MCSRM with practical specifications. Coupled finite element analysis and circuit simulations have been employed to evaluate performance indices including torque ripple, machine iron/copper loss, power factor, winding current density, power converter losses and power densities. The machine-converter system level investigations have confirmed that in the proposed four-phase MCSRM under single pulse control, improved machine performances can be obtained with reduced power converter loss.

The Flux Switching Machine is one of the novel topologies within the hybrid machine class. It has many advantages such as flux focusing effect, compatibility with simple power converters, high fault tolerance with independent concentrated armature windings, mechanical robustness due to its simple salient pole rotor and high power density. With such attributes the machine is a promising candidate for high speed, high power density applications. It includes toothed rotor with permanent magnet excitation and segmented rotor with field coil excitation. This article reports on comparative studies into the mechanical stress, magnetic flux, back EMF, D axis, Q axis inductance and saliency ratio, loss distribution, efficiency and power density for these topologies via finite element analysis under open circuit and various load conditions. Quantitative simulation results reveal that the segmented rotor with field coil excitation topologies exhibit better electromagnetic performance, among which the 12/7 combination of stator pole and rotor segments exhibits superior EM performances than those of other combinations. Parametric analysis with respect to the aspect ratio and rotor segment arc angle are also performed on 12/7 topology to investigate their relationship with the torque, efficiency and power density.

Insulated gate bipolar transistor (IGBT) devices have gained leading position in traction and aerospace applications. The failure of these switches (IGBT) can reduce the efficiency of the system. Two most dominated failure mechanisms of IGBTs are solder fatigue and bond wire lift off. One of the major effects which influence these failure mechanisms is thermal impedance characteristics, which depends on the heat dissipation in the junction. In traction or aerospace application, the operational loads are not always constant. It results in the temperature cyclic in power converter, meaning that change in the device junction temperature. This change in temperature degrades the transient thermal resistance, and induces a mechanical stress especially at contacting surfaces of materials with different coefficient of thermal expansion. This may lead to degradation or complete failure of these components. The aim of this paper is to identify thermal impedance variation due to power cycling and thermal cycling. More importantly which temperature cyclic nature causes degradation in the thermal impedance, and its relation to semiconductor module failure mechanism.

It can be seen presently widespread electrification of high power vehicular systems such as more electric aircrafts and electric ships. To further improve the efficiency, flexibility and reliability of such systems, zonal DC electric distribution technology is proposed. In most cases, the zonal DC bus is fed by front-end AC/DC voltage source rectifiers and is responsible for supporting many onboard loads with complex dynamic characteristics. Due to the small-signal constant power nature of tightly regulated power electronic loads and the large-signal load variations, stability of the zonal DC bus becomes a major concern. It is clear that conventional PI controllers stabilize the system in a small-signal sense. However, they are ineffective under some large-signal disturbances and load changes. Passivity based control method is known to provides global stability under passive loads, such as resistive loads. Nonetheless, the global stability of voltage regulation with nonlinear loads has not been discussed. This paper proposes a cascaded sliding mode control method with global stability and online observation of load power. Moreover, system stability limit constrained by catastrophic bifurcation is also discussed. Simulation results are provided to verify the proposed method.