A hybrid renewable energy source (HRES) consists of two or more renewable energy sources, suchas wind turbines and photovoltaic systems, utilized together to provide increased system efficiency and improved stability in energy supply to a certain degree. The objective of this study is to present a comprehensive review of wind-solar HRES from the perspectives of power architectures, mathematical modeling, power electronic converter topologies, and design optimization algorithms. Since the uncertainty of HRES can be reduced further by including an energy storage system, this paper presents several hybrid energy storage system coupling technologies, highlighting their major advantages and disadvantages. Various HRES power converters and control strategies from the state-of-the-art have been discussed. Different types of energy source combinations, modeling, power converter architectures, sizing, and optimization techniques used in the existing HRES are reviewed in this work, which intends to serve as a comprehensive reference for researchers, engineers, and policymakers in this field. This article also discusses the technical challenges associated with HRES as well as the scope of future advances and research on HRES.

Global transportation has shifted toward electromobility to achieve net-zero emission, and in the next few decades, commercial electric aircraft is likely to become a reality. This transition has embarked on through the existing more electric aircraft (MEA), and the ultimate goal will be potentially achieved by hybrid-electric and all-electric airliners, along with green fuels, such as green hydrogen or supercritical CO2 (sCO2) and its potential Gg CO2 equivalent elimination—with or without combustion. Electric propulsion replaces conventional jet propulsors with electric fans powered by electric generators rotated by an engine, a combination of generators and energy storage, or just energy storage. An appealing idea is to distribute the electric fans along the aircraft wings or tails to improve aerodynamics, boost energy efficiency, and reduce carbon emissions and acoustic noise. Focusing on distributed electric propulsion (DEP) systems, this article reviews the state-of-the-art advancements in aircraft electrification. Three major DEP categories, i.e., turboelectric, hybrid-electric, and all-electric propulsion technologies, are investigated. Although all of them utilize electric fans as propulsors, their system structures and power generation stages are different. Hence, comprehensive considerations are required to optimize the DEP system designs. Starting with the multifarious electrical system architectures proposed in the literature, a thorough review is conducted including the system parametric specifications, design considerations of power converters, the power electronics devices’ characteristics in cryogenic conditions, and various energy storage systems. This review aims to provide a reference to researchers, engineers, and policy-makers in aviation to accelerate the progress toward future net-zero emissions.

Hybrid-electric propulsion system is an enabling technology to make the aircrafts more fuel-saving, quieter, and lower carbide emission. In this paper, a megawatt (MW) scale power inverter based on a three-level active neutral-point-clamped (3L-ANPC) topology will be developed. To achieve high efficiency, the switching devices operating at carrier frequency in the power converter are configured by the emerging Silicon Carbide (SiC) Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs), while the conventional Silicon (Si) Insulated-Gate Bipolar Transistors (IGBTs) are selected for switches operating at the fundamental output frequency. To obtain high power density, dc-bus voltage is increased from the conventional 270V to medium voltage of 2.4 kV to reduce cable weight. Also, unlike the traditional 400 Hz dominated aircraft ac systems, the rated fundamental output frequency here is boosted to 1.4 kHz to drive the high-speed motor, which helps further reduce the motor weight. Main hardware development and control modulation strategies are presented. Experimental results are presented to verify the performance of this MW-scale medium-voltage “SiC+Si” hybrid 3L-ANPC inverter. It is shown that the 1-MW 3L-ANPC inverter can achieve a high efficiency of 99% and high power density of 12 kVA/kg.

Aiming at tolerating common electric faults of multiphase motor drives comprehensively and minimizing the adverse impacts from the remedial scheme itself, a diagnosis-free self-healing scheme is put forward for the open-circuit faults of dual three-phase permanent-magnet synchronous motor (PMSM) drives. Firstly, the self-healing mechanisms of dual three-phase PMSM drives are analyzed in detail. On the basis of theoretical analysis, the repressed self-healing capability of the dual three-phase PMSM drives is fully released by optimizing the current references on harmonic subspace. Since the diagnosis process is not required in the proposed self-healing scheme, the misdiagnosis problem and the prolonged damage caused by the additional time cost of diagnosis can be fundamentally avoided. The proposed self-healing scheme can be generally applied to open-switch faults, single open-phase faults and multiple open-phase faults in the multiphase motor drives. No change is required for the machine model, modulation strategy or control framework under different open-circuit faults. Thus, the complex transition strategies among different fault-tolerant control methods for different faults can be avoided, and the adverse impacts from the remedial scheme itself can be minimized. Experimental verification is presented to prove the validity of the proposed self-healing scheme.

In this paper, diagnosis and tolerant control schemes have been studied for common electrical faults in T-type three-level inverter fed dual-three phase permanent magnet synchronous motor (PMSM) drives for safety-critical applications. Based on vector space decomposition and double three-phase space vector modulation, diagnostic and tolerant control methods have been developed comprehensively for open-phase faults, open-switch faults and short-switch faults in T-type three-level inverter fed dual-three phase PMSM drives, in such way that misdiagnosis of different faults sharing similar faulty features can be avoided. In particular, a two-step diagnostic scheme is proposed in order to simplify the diagnostic process: The first step is to identify faulty phase and fault category by analyzing current trajectories on harmonic subspace, and the second step is to determine the specific fault type in a small fault-searching area obtained from the first step. In the aspect of fault-tolerant control, a novel current compensation method is proposed for open-phase fault without changing the machine model, space vector diagram and the control framework. Open-switch faults and short-switch faults are tolerated by making full use of the remaining vectors after faults. The validity of the proposed fault diagnosis and tolerance schemes have been verified by experiments.

This paper presents the operation principle and benefits of a novel power converter topology named three-level two-stage decoupled active neutral point clamped (3L-TDANPC) converter, which is implemented based on a hybrid utilization of silicon (Si) insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) metal-oxide semiconductor field-effect transistors (mosfets). The 3L-TDANPC converter can achieve high efficiency with limited number of SiC mosfet modules while keeping balanced loss distribution among the switching devices, which helps increase the converter power ratings. In addition, in this 3L-TDANPC converter, the SiC mosfet has a potential to ride through short-circuit fault because of the presence of Si IGBTs. The key challenges that are associated with system resonant current are investigated and the methods to damp such resonant current are proposed and explained in detail. The simulation and experimental results based on a 1-MW 3L-TDANPC converter prototype confirm the expected benefits of this proposed converter and the effectiveness of the proposed resonant current damping methods.